the internet encyclopedia volume phần 8 pptx

VOICE OVER INTERNET PROTOCOL VOIP literally refers to the transmission of a digitizedvoice signal using digital packets, routed using the In-ternet protocol or IP.. On the other hand, us

comes long enough.

All of these deficiencies of a transmission channel have

the effect of reducing the channel capacity, or, throughput,

of a transmission link Channel capacity refers to the

the-oretical upper limit on how much information, in terms

of bits per second, can be transmitted through a channel

(Wozencraft & Jacobs, 1965)

Circuit-Switched Connections of a Call

in a Conventional Telephony Network

VOIP networks must interoperate with conventional

circuit-switched networks, in particular the ubiquitous

public switched telephone network or PSTN A VOIP

network that cannot interoperate with, and therefore

ex-change calls with, the PSTN would be of little value to

most telephone users A network’s value increases as it

can be used to reach more users

Like other networks, the PSTN uses a hub and spoke

architecture of transmission links and switches (Bell

Lab-oratories, 1977, 1983) Each user’s telephone is typically

connected by an individual circuit (usually referred to as

local loop) to a central office switching hub In a small

town, there may be only one central office, whereas in

a large major metropolitan area, there could be several

dozen central offices

In each central office hub, there is usually at least one

switch The switches used in traditional telephony are

called circuit switches A circuit switch will route a call

over a dedicated path from one transmission link to

an-other for at least the duration of the call See Figure 4

As will be described more fully below, this contrasts with

the packet switching used in the Internet, which does

not maintain a dedicated path connecting network links,

but instead passes information along shared paths on a

packet-by-packet demand basis

Dedicated Path Created for Call Duration

Figure 4: Circuit switched connection between

two links

Originating the Call

As Figure 5 shows, when a caller picks up a telephone

to make a call, the local switch in the caller’s local tral office (Node A) provides a dial tone that the callerhears through the telephone That dial tone indicates tothe caller that the local telephone switch has seized his orher local telephone line and is ready to receive the digits

cen-of the telephone number that he or she wishes to dial Theprocesses of seizing the telephone line and returning dialtone are types of supervisory signaling

The caller then enters, or dials, the telephone ber of the called telephone If the calling telephone isenabled with touch-tone signaling, the calling telephonesignals to the local switch the digits dialed by using dif-ferent combination of two touch-tones for each digit di-aled Such transmitting of routing information is calledaddress signaling The caller’s local switch Node A detectsthese tone combinations and, in turn, determines the tele-phone number the caller is trying to call

num-Circuit Switching to the Call’s Destination

Each circuit switch has a routing look-up table for mining how to handle a call based on some or all of thecalling and called numbers If the local switch does nothave adequate information in its routing tables to make arouting decision, most modern switches will hold the call

deter-Link Link

Interoffice Transmission Link

Interoffice Transmission Link

Interoffice Transmission Link

Calling Telephone

Called Telephone Office"

"Central Node A

Node B

"Toll Office"

SS7 Packet Switch

SMS Database

Node C

"Central Office"

Figure 5: Conventional circuit switched telephony network.

V OICE OVER I NTERNET P ROTOCOL 653

and launch a packet data message to an external database

(called a service management system or SMS) That

mes-sage is routed from the switch to the SMS over a

par-allel data network called a Signaling System 7 (or SS7)

packet network The SMS returns routing instructions,

via the SS7 packet network, to the switch that originated

the routing query The SS7 signaling standard came out

of the conventional telephony industry

If the local switch determines that the call needs to beconnected to a local loop attached directly to that local

switch, the switch will ring the local loop of the called

telephone At the same time, the switch returns a ringing

sound signal to the calling party On the other hand, if the

local switch determines that the called party’s telephone

is busy, the local switch returns a slow busy signal to the

calling party

As soon as the called party picks up its phone, the localswitch creates a circuit-switched dedicated audio commu-

nications path between the calling party’s local loop and

the called party’s local loop, thus completing a dedicated

audio transmission path between the calling telephone

and the called telephone For the call’s duration, that

ded-icated audio path is available for the transmission of voice

signals, in both directions, between the calling and called

party’s telephones If one or more of the links used to

co-nstruct that path are digital, a CODEC in the connecting

switch or other connecting device will make the

neces-sary analog-to-digital conversion so that the voice signal

may seamlessly traverse the boundaries between the

ana-log and digital links

If the called telephone’s local loop is not directly nected to the calling telephone’s local switch, the local

con-switch must establish a connection to the called telephone

through another switch or switches For most modern

PSTN switches, this requires that the originating switch

launch an SS7 message, over the SS7 network, to reserve

a path through other switches in the network for

complet-ing the desired communications path to the call’s

destina-tion If the far end switch where the called party is located

determines that the called party’s line is busy, no circuit

connections will be made, the path reservation for the

con-necting links is dropped, and the originating switch will

return a slow busy signal to the calling party However, if

the reason the call cannot be completed is network

con-gestion, the originating switch will return a fast busy to

the calling party

If the called party’s line is not busy and a complete path

to the called party’s line can be established, the called

party’s local switch rings the called party’s telephone

While the called party’s phone is ringing, the calling party’s

local switch is returning an audible ringing signal to the

calling party When and if the called party answers, the

switches instantly circuit-switch together the links along

the reserved path in order to complete a dedicated path

between the calling and called telephones

Finally, it should be noted that some switches nicate interoffice signaling information using non-SS7 in-

commu-teroffice signaling arrangements, such as in-band

signal-ing Regardless of the supervisory and address signaling

arrangement used, the net result of establishing a

commu-nications path between the calling and called telephone

will be the same

VOICE OVER INTERNET PROTOCOL

VOIP literally refers to the transmission of a digitizedvoice signal using digital packets, routed using the In-ternet protocol or IP The driving forces for using VOIPare beliefs in its cost savings, flexibility, and the growingdesire to combine voice and data transmission on one net-work See, e.g., Morris (1998), Cisco VOIP Primer (2002),Matthew (2002)

How VOIP Transmission Works

Because a VOIP call is transmitted digitally, it begins with

a digitization process similar to that used in conventionaltelephony First, the voice signal is sampled at a rategreater than the Nyquist sampling rate, and those sam-ples are digitized Whereas conventional circuit switchedtelephony transmits the digitized samples in a constantstream of synchronized (i.e., equally spaced in time) digi-tal samples, VOIP transmits the digitized voice communi-cations samples in asynchronous (i.e., unequally spaced

in time), sequentially numbered packets of data Eachpacket (which may contain many voice samples) containsits own IP formatted address information, which allows it

to be routed over an IP network Unlike conventional phony, where each sample follows the path of the samplebefore it, each of the IP packets containing several sam-ples of voice data may take an independent path (which

tele-is shared with other data packets) to its destination Witheach packet potentially taking a different route, the pack-ets often can arrive at their destination out of order (orsometimes not at all) At the far end, the IP and other rout-ing information is stripped from the packet, the voice sam-ples are temporarily collected in a buffer and reordered

as required, and then, if all goes well, the original voicesignal is reconstructed, albeit, slightly delayed For VOIPtechnology to have the functionality and flexibility of con-ventional telecommunications, some form of call control,

in the form of supervisory and address signaling, is quired

re-Figure 6 shows the basic VOIP transmission scheme

VOIP Signaling

VOIP signaling refers to signaling that can be used over

an IP network to establish a VOIP call It provides theneeded functionality of supervisory and address signaling.VOIP call signaling comes in two predominant compet-ing schemes: H.323 and Session Initiation Protocol (SIP).Each must satisfy the generic needs of telephonic calling.Specifically, each must provide for the following:

The calling phone to address and signal to the called phone,

tele-The called telephone signaling its availability for receivingcalls,

Establishing a transmission path between the calling andcalled telephone,

The called or calling telephone signaling to the otherphone it has hung up, and

The tearing down the transmission path once the call isover

Figure 6: VOIP network.

Figure 7 shows a generic signaling progression for

es-tablishing a VOIP call that might occur using H.323-type

centralized call control arrangement First, the calling

telephone dials the called telephone’s number (1) The

call-ing phone forwards the dialed telephone number (address

signaling) to a VOIP call controller—which is a special

purpose server That call controller does a lookup (2) in

a database for determining the IP address to reach the

called telephone If the called telephone is on the IP

net-work, a call setup signal is routed to the called telephone

to ring the called telephone (4)

While the called telephone is ringing, a ringing signal

is sent back to the calling telephone (3), which telephone,

in turn, generates a ringing sound in the caller’s earpiece

When and if the called party answers the telephone, a

se-ries of signals to set up the channel path are returned to

the calling and called telephones (5, 6, 7)

A UDP/IP communications path is then set up betweenthe calling and called telephone (8) The digitized voice

is transported using the user datagram protocol (or UDP)

in the transport layer, with two protocols, RTP (real timeprotocol) and RTCP (real time control protocol), ratherthan TCP—which is often used by non-voice data UDP

is connectionless (e.g., packets can take different routes)and can transport data packets without acknowledgingtheir receipt UDP is nonstop with less address informa-tion overhead The tradeoff of using a UDP path is lowerreliability than TCP UDP packets may be dropped or ar-rive out of order, but if they do arrive they do with lessdelay This is a good tradeoff for voice communications,which is highly tolerant to dropped packets, but relativelyintolerant to delay

RTP over UDP provides packet sequence numbering,

so out-of-order and/or missing packets are detectable at

Calling Telephone

Called Telephone

IP Network

IP Router

Call Control

Gateway

1 Dial

2 Look Up Dialed #

3 Generate Audible Ring

4 Ring

5 Hook

Off-7 Open Channel

6 Open Channel

8 RTP (Voice Stream)

IP Packets

Voice Mail

Figure 7: VOIP H.323-type signaling system using central call control.

V OICE OVER I NTERNET P ROTOCOL 655

Calling Telephone

Called Telephone

IP Network

IP Router

Call Control

Gateway

1 Dial

2 Look Up Dialed #

3 Generate

4 Ring

5 Hook

Off-7 Open Channel

6 Open Channel

8 RTP (Voice Stream)

IP Packets

Voice Mail

5 Called Phone Does Not Answer Audible Ring

Figure 8: Called telephone unavailable with reroute to voice mail with H.323-type signaling.

the far end RTCP provides a separate signaling

chan-nel between the end devices (e.g., telephones) to allow

exchange of information about packet loss, packet jitter,

and packet delays, as well as additional information, such

as the source’s name, e-mail, phone, and identification

(Real-Time Transport Protocol [RTP], 2001, August), and

(Streaming Video Over the Internet, 2002)

Additional requirements for a commercial VOIP tem include being able to produce information for billing

sys-and/or accounting for calls Similarly, today’s users

de-mand that it provide other features, such as Caller ID and

voicemail These capabilities may reside in the call

con-troller, IP telephones, and/or other devices in the IP

net-work Figure 8 shows how voicemail can be provided with

H.232

H.323 vs SIP

In addition to H.323, SIP is the major competing standard

for VOIP signaling They have both evolved to offer very

similar feature capabilities

H.323 takes a more telecommunications-oriented proach than SIP SIP takes an Internet-oriented approach

ap-H.323 is the older of the two (Doron, 2001; Paketizer,

2002) It was developed under the International

Telecom-munications Union (ITU), a telecomTelecom-munications

stan-dards group, and has gone through various revisions

(ITU-T, Recommendation H.323, 2000) The latest version

of H.323 standard (H.323 v3) is very robust in that it

cov-ers many possible implementations However, H.323 is

considered more difficult to implement than SIP due to

its use of binary encoded signaling commands

H.323 v.3 can be implemented with or without a callcontrol server Thus, an H.323 v.3 end device (e.g., a tele-

phone) can be designed to either set up a call through a

call control server, or set it up directly with another end

device without using an intervening call control server

An H.323 v.3 call control server can be set up to relay the

communications stream during the call, or the end devicescan directly establish the communications RTP streamingchannel between themselves The call control server can

be either stateless (i.e., not track a transaction or a sessionstate) or stateful (i.e., track a transaction and/or call ses-sion state) The significance of this is that in the statefulconfiguration, H.323 v.3 is not as scalable Finally, H.323v.3 employs signaling protocols that can easily be mappedthrough a gateway for routing calls between the VOIP net-work and the public switched network

SIP is a Web-based architecture that was developedunder the Internet Engineering Task Force (IETF) LikeURLs and Web e-mail, SIP’s messages are in ASCII textformat that follow the HTTP programming model, i.e.,using a grammar similar to that used to create basic Webpages—resulting in slightly lower efficiency in transmit-ting signaling information, as compared to the more ef-ficiently encoded binary H.323 signaling messages Also,SIP is very extensible, leading many vendors to implementvariations that may be somewhat incompatible (IETF, SIP,2003; IETF, SIP RFC2543bis, 2002)

An address used for routing a SIP messages is of theform SIPAddress@xyz.com As shown in Figure 9, when

a phone wishes to originate a call, it transmits an ASCIISIP “INVITE” message (1) addressed to the SIP address ofthe called phone (e.g., sales@xyz.com., where “xyz.com”

is the domain name of the SIP proxy server for the calledphone) Using conventional domain name server (DNS)lookup, the internet routes this e-mail-type message tothe SIP call control server, which may act as either aproxy server or a redirect server for the domain of thedialed called telephone address (here, xyz.com) In order

to determine where the telephone is located, the proxyserver or redirect server will query a location server (2),which will return the routing directions What happensnext depends upon whether the call controller is act-ing as a proxy server or a redirect server for the calledtelephone

Calling Telephone

Called Telephone

6 OK to Caller@SIP.COM

8 ACK to

IP of xyz

9 RTP (Voice Stream)

IP Packets

xyz@195.37.78.173 Caller@SIP.COM

4 RING to Caller@SIP.COM

1 INVITE to abc@xyz.com

3 INVITE to xyz@195.37.78.173

Figure 9: VOIP call routed using SIP signaling.

For a proxy server, the location server will return the

IP address for the called telephone Using that IP address,

the SIP INVITE message will be directed to the called

tele-phone (3) along with the calling teletele-phone’s IP address

The called telephone will then return a “RING” message

to the proxy server (4), which then forwards that RING

message to the originating telephone (5) When the called

phone answers, an OK message is returned (6, 7), which

includes the called telephone’s IP address Finally, the

originating telephone (which now knows the IP address

of the destination phone from the INVITE/OK message

exchange) sends an “ACK” message to the IP address of

the called telephone (8) The originating telephone then

establishes an RTP communications link with the called

telephone (9)

For a redirect server, the location server will

re-turn the redirected (i.e., forwarding) e-mail-style SIP

ad-dress of the called telephone (e.g., sales@home.com, or

joe@home.com) The redirect server will then forward the

INVITE request to the proxy or redirect server associated

with that redirected address, and then the steps

enumer-ated above will take place

Each location server must track the IP address of each

of the telephones in its SIP domain Thus, each SIP

tele-phone must register with its domain’s location server via

a registration server of its telephone service provider An

individual telephone can be registered with any

registra-tion server with which the user has a service arrangement

Registration binds each SIP telephone’s IP address to its

SIP address in its service provider’s domain

Note that a SIP call control server’s primary purpose

is to handle the routing of initial supervisory and

ad-dress signaling information Also note that, after the

ini-tial exchange of supervisory and address information, SIP

end devices establish and maintain the communications

channel without involvement of the SIP call control server.Like H.323 v.3, the SIP packets that carry the signalingmessages almost always follow a different path from thepath taken by the communications data Finally, with SIPmost of the intelligence resides in the end devices, as com-pared to being in the network, as is the case with conven-tional telephone networks and with H.323

Because SIP proxy and redirect servers typically donot track a call’s status after the call is set up, SIP is of-ten viewed as being more scalable than H.323 When acall control server is configured to track call status, its re-sources must bear the added burden of such monitoring.SIP’s ASCII encoding is considered more extensibleand open than the binary encoded signaling of H.323 v.3.SIP uses a very generic syntax for messages, which can

be customized to fit the needs of different applicationsresident on end devices For analysis of the various (andsomewhat controversial) comparisons of SIP and H.323,see Dalgica and Fang (1999)

Integrating VOIP Into Conventional Circuit-Switched Telephony Networks

As previously noted, the value of a telephony network is

a direct function of how many telephones are directly orindirectly connected to it; thus a VOIP network must beable to exchange calls (i.e., internetwork) with the PSTNsuch that a VOIP user can originate telephone calls toand receive telephone calls from a telephone user who isconnected to the PSTN In addition, for conventional tele-phone providers to deploy VOIP technology inside theirnetworks, VOIP technology’s presence must be impercep-tible to their existing base of telephone users

Figure 10 illustrates how a VOIP call can make a nection from a phone connected to an IP network to

con-V OICE OVER I NTERNET P ROTOCOL 657

Calling Telephone

Called Telephone

IP Network

IP Router

or Switch

Call Control

Gateway

2 Look Up Dialed #

4 Generate

4 Call

4b Hook

Off-5 Open

6 Open Channel

8 RTP (Voice Stream)

IP Packets

Voice Mail

* SS7 connection if Gateway

Is Carrier Provided

7.Call Setup

1 Dial

Figure 10: VOIP signaling internetworking with public switched network (PSTN).

a phone on a PSTN network A device, called a

gate-way, is used to translate signaling messages across the

VOIP/PSTN network boundary and to transform the

jit-tery voice packets on the IP side of the gateway into a

synchronous stream of voice data information (if there is

a digital voice circuit on the other PSTN side of the

gate-way) or an analog voice signal (if there is an analog voice

circuit on the PSTN side of the gateway)

On the IP side, the VOIP signaling to the gateway looksmuch the same as the signaling that would be done to

another end device on the IP network

ENUM, the Fully Interoperable

Numbering Plan

ENUM is a new standard for numbering plans that

would allow seamless telephone number addressing

be-tween conventional and VOIP telephony See, e.g., Neustar

(2003) and IETF, Telephone Number Mapping (ENUM)

(2003) It unifies Internet and conventional telephone

ad-dressing schemes by mapping E.164 (i.e., conventional

telephone) numbers to a URL Internet (and SIP)-friendly

format With ENUM, a single global digital identifier

sys-tem can serve equally subscribers attached to the PSTN

or the Internet The same identifier can be used to identify

multiple devices, such as plain telephones, fax, voicemail,

and data services, regardless of whether they are on the

PSTN or public Internet, thus conserving scarce E.164

numbers and domain name resources

As an example, a telephone number 1-305-599-1234would map onto the URL 4.3.2.1.9.9.5.5.0.3.1.E164.arpa

A DNS query on this domain name would return a number

of records, each listing a specific service registered to theowner of the E.164 number Devices and services attachedanywhere on the public Internet or PSTN could be regis-tered to this universal, fully portable, single number iden-tifier of their registered owner, allowing mobility aroundboth the PSTN and the public Internet

The ENUM standards raise new issues of privacy, curity, and administration Also, final agreement betweenInternet and traditional telecom industry represented bythe ITU is still pending

se-Quality of Service Issues

Transmission and routing can introduce effects that grade the quality of VOIP VOIP signals are not immune

de-to the deficiencies of the facilities that transport and routethem These deficiencies can cause packet loss, jitter, anddelay

Packet loss refers to the loss of packets containing some

of the voice samples during transmission The loss might

be caused by high bit error rates in the UDP transmissionchannel, misrouted packets, and/or congestion causingintermediate routing devices to drop packets Becausevoice transmission is very sensitive to delay, the reassem-bly of the voice signal at the receiving end of the callcannot typically wait for the retransmission of erroneous

or misrouted packets However, voice transmission has

a high tolerance for packet loss—mainly because the timate receiver of the signal (the human ear and/or in-tervening CODEC) does a good job of interpolating (i.e.,filling in the gap) where a packet has been lost There is alimit to how much packet loss can be tolerated That limit

ul-out redundancy, some CODECs that use data compression

algorithms are not able to recover from the loss of as few

as two packets in a row

Jitter can also contribute to lower quality With IP

traffic often taking multiple routes and/or mixed in with

bursty IP packet traffic, the interarrival times of the

pack-ets at the receiving end may be irregular and/or the

packets arrive out of order Jitter can be overcome by

buffering the packets—i.e., temporarily storing them long

enough to reorder them before forwarding them to the

de-coder However, buffering has the negative consequence

of adding more delay

Delay in the transmission of voice packets can be

mini-mized in several ways One is overbuilding the IP network,

i.e., ensuring that there is always excess capacity in the IP

network for all traffic, including during peak traffic

peri-ods Alternatively, priority routing can be afforded to voice

traffic, at the expense of lower priority data traffic—which

is more tolerant of delays Separate treatment of voice

from data can be done by virtual segregation or physical

segregation from lower priority traffic The former can be

done at either the network or data link layer For

exam-ple, segregation can be done at the data link layer by using

separate ATM channels for voice and data traffic and then

assigning ATM-based priority treatment to the ATM

chan-nels carrying voice traffic Where voice and data are mixed

on the IP network, identifiers can be used to indicate to the

intermediate network components (such as routers) that

designated traffic (such as voice traffic) should be given

priority

An example of this last method is RSVP, the Resource

Reservation Protocol RSVP allows a VOIP application to

request end-to-end QoS guarantee from a network (Cisco,

VoIP Call Admission Control Using RSVP, 2003) If the

guarantee cannot be provided, the call will not be

al-lowed to go through Where the guarantee cannot be

se-cured, the traffic might be redirected to an alternate

net-work or blocked (resulting in VOIP users receiving an

“equipment busy” signal) At the current time, priority

schemes such RSVP typically do not work over the public

Internet (with a large “I”) This is because, among other

reasons, the economic incentives are not there for

inter-mediate Internet providers to honor any type of

priori-tization routing scheme, given that their reimbursement

is the same for all traffic—regardless of its priority

desig-nation Therefore the current market structure for public

Internet backbone routing prevents the realization of a

higher quality of service for VOIP traffic over the public

Internet

To differentiate themselves, some Internet backbone

providers are introducing prioritization schemes such as

MPLS-based networks, which are ATM-like in their

at-tributes, but operate at a mixture of layer 2 and 3

proto-cols in pure IP environments As competition intensifies,

public networks are expected to become friendlier to

real-time services such as VOIP Quality of service is discussed

in detail elsewhere

However, such efficiencies will tend to be most cant to private networks and/or network providers whosetransmission networks are capacity-constrained

signifi-A second source of VOIP’s cost savings is lower capitalcost per call using lower cost switching devices (i.e., In-ternet routers and switches) Again, networks with sunkinvestments in conventional technology with excess ca-pacity would derive little benefit from such savings

A third source of VOIP’s savings is lower costs of ministration, particularly in enterprise environments Agood deal of administrative cost is incurred in enterprises

ad-to accommodate the movement of telephone users withinthe enterprise Each time a user moves to another office

or enters or leaves the firm, the routing tables and tory of a conventional telephone system must be updated,often manually VOIP’s self-registration feature eliminatesthese administrative costs

direc-A fourth source of VOIP’s savings comes from the

“economies of scope” that VOIP can achieve by its ability

to intermingle with other traffic on data networks, inating the need to segregate voice and data traffic, as isoften done with conventional telephony These savings aremost easily exploited in the LAN and WAN enterprise envi-ronment or by data-centric carriers who wish to combinetheir voice and data traffic Administrative savings alsocome from eliminating the conventional regime of sepa-rate administrative staffs for voice and data

elim-Finally, VOIP traffic on a data network looks like anyother data on that network This allows some carriers andenterprise users to avoid some of the economically dis-torting taxes that local, federal, and foreign regulatoryregimes place on pure voice traffic, but not on data traffic

It is important to remember that the realization of thesesavings are application-specific and may not be realized inevery situation See, e.g., Morris (1998) and “Cisco SeeksBigger Role in Phone Networks” (March 15, 2003)

Security Issues for VOIP

Security is a concern with VOIP, particularly because ofthe distributed nature of the call control, much of which ishandled between end devices (Cisco, SAFE: IP TelephonySecurity in Depth, 2002) Some of the things that makeVOIP attractive, e.g., self-registration of end devices andsoftware-controlled PCs acting as end devices, are alsothe sources of VOIP’s vulnerability Security issues includefour categories: (1) eavesdropping, (2) toll fraud, (3) iden-tity spoofing, and (4) IP spoofing

Eavesdropping refers to an unauthorized party tening” to the packets and, in turn, being able to listen

“lis-to the voice conversation This problem exists with bothVOIP and conventional analog/digital voice communi-cations In both cases, the simplest method of prevent-ing this problem is to encrypt the digital signal at itssource, the originating telephone The problem encryp-tion brings is overhead and computational load, whichcan introduce delay Also, encryption can create problems

R EFERENCES 659

for law enforcement agencies where they have a warrant

to wiretap a telephone conversation

Toll fraud is the problem of unauthorized persons ing telephone calls over the network This can be caused

mak-by unauthorized users originating calls on the IP network

either on legitimate phones or over illegitimate phones As

with conventional telephony, this can be combated with

security codes and other authentication methods

Identity spoofing refers to a hacker tricking a remoteuser into believing he or she are talking to the person he

or she dialed on the IP network, when, in fact, he or she

is talking to the hacker Again, security codes and other

authorization methods are helpful here

IP spoofing refers to theft of IP identity, where one enddevice is able to convince the IP network that its IP ad-

dress is the same as a legitimate device’s IP address This

allows the device with the fraudulent IP address to

inter-cept calls and/or perform toll fraud using that IP address

Spoofing the IP address of a gateway allows

eavesdrop-ping on telephone calls

Some generally accepted recommendations for imizing many of these security problems are to disable

min-self-registration of VOIP end devices after initial network

installation, to segregate voice from data traffic at level 2

or 3, and to use a stateful firewall at the PSTN gateway

As noted above, segregating data from voice services also

provides the added benefit of maintaining different

qual-ity of service for data and voice

CONCLUSION

VOIP holds great promise where the convergence of data

and voice can occur Internetworking and overcoming

QOS issues remain some of the biggest challenges

GLOSSARY

Analog signal A continuous signal that, at any point in

time, can have an infinite number of possible valuesand that is typically analogous in some characteristic

to another signal or physical phenomenon

Asynchronous transfer mode (ATM) A network

trans-fer method, employed at the data link layer (Level 2),for high-speed switched packet routing, which can es-tablish virtual channels with a specified QoS

Channel capacity The theoretical upper rate limit, in

bits per second, at which information can be ted over a transmission channel

transmit-Circuit switch A switch that makes a temporary or

permanent dedicated transmission path between twotransmission links that are attached to that switch,based on signaling information received prior to es-tablishing the dedicated path

Digital encoding Encoding a signal in the form of a

string of 1s and 0s

Digital transmission Transmission of information

en-coded as 1s and 0s

Internet A global public network based on the

“Inter-net protocol,” connecting millions of hosts worldwide,and for which users often pay a flat fee to access, withlittle or no charge for transmitting each packet of in-formation (Outside the U.S., Internet access is often

measured and charged on a usage basis, e.g., minutes

or units of data.)

Internet protocol (small “i”) or IP A packet ing protocol used for routing packets over and betweenand private networks that is “connectionless” (i.e., eachpacket making up the same message may take a differ-ent route to reach the ultimate destination)

switch-Node A point of connection between transmission links,which may contain switches, and/or may contain con-verters to interconnect transmission links with differ-ing modalities (e.g., for connecting wire links to wire-less links, non-digitally encoded links to digitally en-coded links, or fiber links to copper wire links)

Packet router A type of packet switching device thattypically routes based on Level 3 network address in-formation (such as an IP address) and typically has theability to choose optimal routing based on dynamicallychanging criteria and routing tables

Packet switch A type of packet switching device thatroutes packets of data between links based on addressinformation associated with each packet A Level 3switch uses network addresses, such as IP addresses,

to route packets of data Level 2 switches uses data linklayer addresses (which are typically local and/or hard-coded) for routing

Public switched telephone network (PSTN) A switched network that is provided by regulated com-mon carriers who offer their voice telephone services

circuit-to the general public

Quality of Service (QoS) A set of performance eters or criteria, such a bandwidth, jitter, packet loss,and delay, prespecified for a service

param-Transmission The movement of information (whether

or not digitally encoded) from one point to another via

a signal carried over a physical medium, such as wires,fiber, radio, or light

Transducer A device actuated by signal power from onesystem and supplying signal power in another form

to a second system (e.g., a telephone receiver earpieceactuated by electric power of a received transmissionsignal and supplying acoustic signal power to the sur-rounding air, which the telephone user can hear, or atelephone microphone that has a quartz crystal thatproduces electrical signal power for transmission overwires from the mechanical acoustic power originatingfrom the telephone user’s voice)

Transmission link A transmission path connecting twonodes

Voice communication The transmission of tion contained in a voice signal

informa-CROSS REFERENCES

See Circuit, Message, and Packet Switching; Digital

Com-munication; Internet Literacy; Public Networks; TCP/IP Suite; Web Quality of Service; Wide Area and Metropolitan Area Networks.

REFERENCES

ASCII Table Retrieved March 23, 2003, from http://web.cs.mun.ca/∼michael/c/ascii-table.html

Cisco, VoIP call admission control using RSVP (2003).

Retrieved March 25, 2003, from http://www.cisco.com/

univercd/cc/td/doc/product/software/ios121/121newft/

121t/121t5/dt4trsvp.htm

Cisco, VOIP primer (2002) Retrieved March 25, 2003,

from http://www.cisco.com/univercd/cc/td/doc/product/

access/acs mod/1700/1751/1751 swg/intro.htm

Cisco, Understanding codecs: Complexity, hardware

support, MOS, and negotiation (2002) Retrieved

March 25, 2003, from http://www.cisco.com/warp/

public/788/voip/codec complexity.pdf

Cisco, SAFE: IP telephony security in depth (2002)

Re-trieved March 25, 2003, from http://www.cisco.com/

warp/public/cc/so/cuso/epso/sqfr/safip wp.htm

Dalgic, I., & Fang, H (1999) Comparison of H.323

and SIP for IP telephony signaling Retrieved

March 25, 2003, from http://216.239.57.100/cobrand

univ?q=cache:PNnMM0MUWcsC:www.cs.columbia

edu/∼hgs/papers/others/Dalg9909 Comparison.pdf+

dalgic&hl=en&ie=UTF-8

Doron, E (2001) SIP and H.323 for voice/video over

IP—Complement, don’t compete! Internet Telephony.

Retrieved March 25, 2003, from http://www.tmcnet

com/it/0801/0801radv.htm

Internet Engineering Task Force (IETF) SIP (2003)

Retrived March 25, 2003, from http://www.ietf.org/

html.charters/sip-charter.html

Internet Engineering Task Force (IETF) Telephone

num-ber mapping (ENUM) (2003) Retrieved March 25,

2003, from

http://www.ietf.org/html.charters/enum-charter.html

March 25, 2003, from http://www.itu.int/rec/recommendation.asp?type=items&lang=E&parent=T-REC-H.323-200011-I

Morris, R L (1998) Voice over IP telephony: Sizzle orsteak? Retrieved March 25, 2003, from http://members.aol.com/ ht a/roym11/LoopCo/VOIP.html

Neustar (2003) Retrieved March 25, 2003, from http://www enum.org

Newton, H (1998) Newton’s telecom dictionary (14th

ex-panded ed.) New York: Flatiron Publishing

Cisco seeks bigger role in phone networks (2003,

Ma-rch 3) New York Times Retrieved MaMa-rch 25, 2003,

from http://www.nytimes.com/2003/03/03/technology/03CISC.html?tntemail1=&pagewanted=print&position

=topPacketizer, T M (2002) Comparisons between H.323and SIP Retrieved March 25, 2003, from http://www.packetizer.com/iptel/h323 vs sip/complist.htmlReal-Time Transport Protocol (RTP) (2001, August) Re-trieved March 25, 2003, from http://www.cs.columbia.edu/∼hgs/teaching/ais/slides/rtp.pdf

Sanford (1999) Packet voice technology: Cheap talk?Retrieved March 25, 2003, from http://www.applied-research.com/articles/99/ARTicle10Sanford.htm

Truxal, J G (1990) The age of electronic messages.

Cambridge, MA: MIT Press

Streaming video over the Internet (2002) RetrievedMarch 25, 2003, from http://www.streamdemon.co.uk/tranproto.html

Wozencraft, R., & Jacobs, M (1965) Principles of

commu-nications theory New York: Wiley.

W Web-Based Training

Patrick J Fahy, Athabasca University

Web-Based Training (WBT): Background 661

Training Principles and Technological

As part of corporate health, even survival, companies and

training institutions globally have recognized the need

to provide relevant and flexible training Professional

de-velopment (PD) in the form of upgrading, re-training,

and various educational opportunities is seen as

enhanc-ing the skills of valued employees, helpenhanc-ing organizations

maintain their competitive advantage by developing (and

thereby retaining) experienced people

Well-designed Web-based training (WBT) can offervaluable advantages over other types of training deliv-

ery in a wide variety of public and private environments:

training time and travel can be reduced, even eliminated,

lowering costs; materials stored on central servers can be

continually revised and updated, assuring currency and

enhancing quality; training content is more consistent,

supporting higher standards; greater efficiency (chiefly

the result of individualization) can increase trainee

learn-ing and satisfaction, improvlearn-ing motivation; and

produc-tion and delivery of training programs may be more

sys-tematic, improving the cost-effectiveness of development

At the same time, using the World Wide Web (WWW)for training presents some challenges: existing training

materials must usually be redesigned, sometimes

exten-sively; bandwidth limitations (often at the user’s end, in

the “last five feet” of the communications chain) may

re-strict or even prohibit use of multimedia by some trainees;

all participants (trainees and instructors) must learn new

skills to use WBT effectively; and an initial investment

(sometimes substantial) in equipment and expertise may

be needed Other factors in the structure or culture of a

training organization may also need to change to make

WBT feasible Dropout rates (admittedly often a problem

in WBT) may indicate the health of WBT programs: high

rates may mean a mismatch between trainees’

expecta-tions and the instructional design of the training material,

or may reveal a lack of leadership or management support(Frankola, 2001)

In this chapter, WBT will be discussed from theoreticaland practical perspectives: important training principlesare reviewed briefly, including basic concepts now com-mon in WBT; practical problems in WBT are considered,

as well as the strengths and weaknesses of this mode oftraining delivery; and finally the prospects for the future

of WBT, and some of the pedagogic, technical, and nomic assumptions on which the optimistic predictionsdepend, are considered

eco-Training Principles and Technological Developments Supporting WBTPioneering Ideas in Training

In the first half of the 20th century, pioneering researcherssuch as Thorndike (1971), Dewey (1938), Skinner (1971),and Keller (1968) conducted research that began identi-fying fundamental learning principles (While these fig-ures wrote and researched in the fields of psychologyand education, their theories have evolved so that theyare now used in the design of effective teaching andtraining of all kinds, including WBT.) Thorndike’s threefundamental behavioral laws were among the first dis-coveries: (1) repetition strengthens any new behavior;(2) pleasure or reward associated with a particular behav-ior increases the likelihood the behavior will be repeated,while pain or lack of reward may diminish the likelihood;and (3) an individual’s personal readiness is crucial to theperformance of any new skill or behavior (Saettler, 1990).Dewey added that individual trainee differences werecrucial in the success of training Dewey and Piaget(1952) both recognized the importance of each individ-ual learner’s personal background, and advocated thattrainees’ experiences and previous learning be considered

661

1960s By describing the teacher or trainer as “the

manager of the contingencies of reinforcement” in the

learning process, Skinner helped found the fields of

educa-tional technology and information processing psychology

Besides a new role for the instructor, Skinner’s work

illustrated points vital to the subsequent development

of technology-based training, including the value of “the

program over the hardware,” and the critical importance

of the learning materials and the organization of the

lear-ning environment (Saettler, 1990)

Keller’s Individually Programmed Instruction (IPI)

model applied Skinner’s discoveries about the importance

of instructional design The IPI model (often called the

Keller Plan) emphasized individual differences in

instruc-tion and evaluainstruc-tion IPI stressed such principles, later

core to WBT, as self-pacing, mastery before advancement,

high-quality materials, tutoring help, prompt feedback,

and practice testing (Fox, 2002) Experiments in teaching

Morse code to World War II recruits demonstrated

con-vincingly that these principles could dramatically increase

the efficiency of training

Innovations such as IPI were impressive, but they

encountered resistance for several significant reasons

relevant to WBT:

rAs innovations, technology-based training models

of-ten make new demands upon institutions, trainers, and

trainees In particular, technology-based training

deliv-ery increases the responsibility of trainees for their own

learning, while reducing instructors’ “platform

behav-ior,” serious flaws in the eyes of some trainers (and some

trainees)

rTechnological innovations may initially result in a

judg-ment of “no significant difference” in performance when

evaluated Time may be needed to reveal their true value

rTepid managerial support may doom a technological

innovation, especially if time and funds are needed to

prove its actual potential

rIndividualized training models usually require more

ad-vance planning and preparation, while (at least initially)

increasing workloads on instructors and administrators,

and possibly destabilizing programs while adjustments

are occurring Participants must be aware of these, and

must be prepared to work through them

rWhen granted responsibility for managing their own

learning, some trainees may respond with demands for

more individual treatment, including access to records

of personal achievement, and remedial and accelerated

options Overall, in individualized programs trainees

ex-pect their individual performance, needs, and

prefer-ences to be acknowledged

In the 1960s and 1970s, developments in

instruc-tional design, cognitive and behavioral psychology, and

organizational analysis converged to produce new tools

and approaches for the design and delivery of

train-ing, which would quickly impact the emerging field of

Gagne and Leslie Briggs (1979), Leslie Briggs and WalterWager (1981), and Walter Dick and Lou Carey (1978).There were certainly others, but these individuals led theway

The Internet as a Training Platform

The earliest forms of the Internet emerged as training wasbeing transformed by a new understanding of learningitself The fact that the Internet today supports a stag-gering array of commercial and educational enterprisesand utilities (browsers, search engines and indexes, mediaplayers and plug-ins, mark-up languages and authoringtools, etc.) is due in part to the commitment to opennessand accessibility, and recognition of the importance of in-teraction as a learning support, made in the early days

of its development The validity of the vision of the earlydevelopers of the Internet of an infrastructure of open,flexible protocols and common standards can be seen inthe fact that the Internet’s first “killer app” was electronicmail (e-mail), still the most used tool on the Internet today.The early developers’ commitment to cooperation andcollaboration reflected in the modern Web’s friendlinessand durability helps make it a powerful tool for (amongmyriad other things) delivering accessible training (Leiner

de-tially, CBT systems such as PLATO (Programmed Logic

for Automated Teaching Operations) and TICCIT shared, Interactive, Computer-Controlled Information Tele- vision) were costly, experimental, and rudimentary: text

(Time-was the mode of presentation, using only occasional ple line drawings or diagrams, with minimal or no anima-tion, sound, or color

sim-Technical milestones passed quickly in CBT over thenext two decades: IBM mainframes were programmed

to teach binary arithmetic; mainframe PLATO andTICCIT were used in college teaching (TICCIT was lateradopted by the U.S Navy); authoring languages such as

Coursewriter and PILOT permitted instructors to

pro-duce instructional and testing materials for mainframedelivery and, later, for PCs (Rutherford, Patrick, Prindle,

& Donaldson, 1997); and multimedia platforms usinglaserdisc and, later, CD-ROM were perfected for storageand portability

The personal computer revolutionized and gave a hugeboost to CBT Apple, IBM, and IBM “clone” personalcomputers (PCs) became increasingly powerful As pricesdropped, the appeal of desktop technology grew; asauthoring capabilities increased, enthusiastic individualsspent money, time, and energy on CBT programmingprojects (sometimes duplicating the efforts of others, and,

U SING THE W EB FOR T RAINING 663

due to the lack of careful instructional design, frequently

producing materials of marginal training value) The

need was clear for a way to link desktop computers for

delivery of CBT, in order to increase access to quality

information and training resources, reduce needless

duplication and unnecessary competition, and facilitate

the fundamental goals of collaboration and cooperation

among developers and users

Computer-Based Communications

While specialized uses of proprietary CBT systems were

expanding and the lack of effective communications

among users was creating obvious training inefficiencies,

promising first steps toward use of computers in an open,

publicly accessible network were being made, initially, in

1962, with the U.S military’s ARPANET initiative ARPA

(Advanced Research Project Agency) proposed an online

research network to link defense contractors and

aca-demics with the military, and with each other

Attemp-ting to use the computers of the time as interactive

communications devices to promote collaboration was

considered novel, and was questioned technically as well

as practically by those who still saw the computer as only

“an arithmetic engine” (Hauben, 1994) However, in 1972,

by the time the final ARPANET report was produced, the

feasibility and usefulness of computer-based networked

communications was established Legacies of ARPANET,

including tools such as file transfer protocol (FTP) and

TCP/IP (transfer control protocol/Internet protocol, a

re-liable packet-addressing, flow-control, and loss-recovery

tool), were available and were subsequently incorporated

in the first Web browser, Gofer, in the early 1990s, and

in the first true graphical browser, Mosaic, in 1993 Even

more importantly, the principles of free communication

and interaction were also reflected in the open and

unreg-ulated architecture of the early commercial Internet

USING THE WEB FOR TRAINING

Strengths

The early Internet, with its ease of access and openness,

appealed to trainers who were previously forced to rely

upon standalone CBT, or pay high costs to access

pro-prietary online training networks However, previous

ex-perience with CBT had shown that a networked training

system would need to include certain features to be

max-imally effective, such as a common interface and

deliv-ery format, interoperability among different desktop and

server systems, and aids to communication and

collab-oration, to make development and production processes

more efficient, in the form of flexible and robust

inter-active capabilities The Web, because of its

fundamen-tal openness and flexibility, from the beginning proved

impressively capable of accommodating these and many

other functions

A Common Training Platform

The Web had evolved to commercial viability by 1995

(In August of that year, Netscape went public with a

hugely successful IPO on NASDAQ.) It was obvious that

for the Web’s widespread adoption, the PC would be the

key technology: when networked, the computer would

be the critical convergence device for this new means of

communication and collaboration With access to the ternet via a properly equipped computer, anyone, includ-ing training providers and their clients, could share theWeb’s growing “super-network” of services and resources,including training, from virtually anywhere in the world

In-Interoperability

Previously, the costs and complexity of developing onlinematerials were greatly inflated by the need to produce ver-sions meeting the specific requirements of hardware plat-forms, configurations, and operating systems The Web,using cross-platform “mark-up” (as opposed to program-

ming) languages such as HTML (hypertext markup

lan-guage), SGML (standard general markup lanlan-guage), and the

powerful XML (extensible markup language), made

hard-ware and operating system characteristics largely vant to Web access

irrele-Although markup languages and the Web’s erability capabilities eliminated many barriers to accessarising from system differences, issues still persist to-day because the Web grants users great freedom in theirchoices and configurations of software and hardware.Issues arise from, for example, differences in display hard-ware (monitors) and screen resolutions, Internet connec-tion speeds (still considered the greatest limitation toaccess of new, multimedia material), and user settings forfonts, background colors, display resolutions, etc., whichcan dramatically change the appearance and effectiveness

interop-of training materials (Jones & Farquhar, 1997) Problemsmay also arise with new versions or updates of commonbrowsers, plug-ins, and other required software, whichoccasionally fail to perform as well as previous versions,and may even contain fatal bugs To address these poten-tial problems, training programs often publish suggestedstandards for hardware and software (including version

or “build” numbers and any required patches or servicereleases for software), to guide trainees in upgrading theirsystems for full compatibility

Training Efficiency

Though costs of initial development were high, it wassoon clear that properly designed WBT could deliver im-pressive results, especially for the highly motivated andwherever cutbacks threatened to affect the quality offace-to-face programs (due to larger training group sizes,limited modes of content presentation, declining oppor-tunities for remediation or individual tutoring, reducedinteraction generally, etc) Some advantages favoringquality WBT over typical site-based face-to-face deliveryincluded self-pacing and individualization; greater em-phasis on learning, less on instruction (seen in the empha-sis on high-quality materials); learner control and auton-omy in the training process; more flexible and convenientremote access to training opportunities; quicker and morepersonalized feedback; peer-to-peer social interaction;and timely, on-demand access to preparation, remedi-ation, review, and outside resources These advantageswere observed early, and led some observers to claim thatWBT could be superior in quality to even well-designedand properly conducted face-to-face training, especiallywhen training group sizes grew larger (Harapniuk, Mont-gomerie, & Torgerson, 1998; Kaye, 1989; Wagner, 1994)

designed to take full advantage of the Web’s potential

ef-ficiencies and conveniences As bandwidth increased, a

progressively more “media-rich” experience could

poten-tially be delivered to trainees almost anywhere (Ironically,

although asynchronous training provided maximum

con-venience and lower direct delivery costs, the temptation to

use rich multimedia-based synchronous [same-time]

ses-sions, more feasible as bandwidth increased and became

cheaper, created some of the same problems of

inflexi-bility and inconvenience as face-to-face training formerly

did for users who lacked access to high-bandwidth

Inter-net services.)

Weaknesses

Some basic weaknesses were soon evident in Web-based

training, too: unless developers employed instructional

design principles skillfully and conscientiously, the

qual-ity and integrqual-ity of materials were sometimes uneven;

navigation among linked sites could become a nightmare

for the unwary or inexperienced; and users needed to

possess and consistently practice self-discipline to avoid

being side-tracked by online distractions

Quality

Quality continues to be a problem on the Web, because the

public Internet by definition is a loosely coordinated (not

controlled) network of networks No one is accountable

for the quality of what is found anywhere on the Web, or

for maintaining functionality: anyone may post

informa-tion (or misinformainforma-tion), so points of view masquerading

as fact are common (Warren, Brunner, Maier, & Barnett,

1996), and important links may simply fail to connect if

not updated frequently For these reasons, the provenance

of any Internet-based information must always be

ques-tioned, and linking to Internet materials for training is

risky as there is nothing to prevent content from

chang-ing, or links from disappearing altogether Increased

se-curity of access and control over content are arguments

for intranet delivery of training.

Structure and Navigation

Just as no one oversees the quality of materials on the

Web, no one assures that Web pages articulate clearly

Retracing one’s steps can be a challenge, even for

ex-perienced users The Internet is like a library where all

the books have lost their identification codes, and some

their bindings The unwary may quickly become lost in

cyberspace

User Control and Orientation

A strength of the Web—the freedom to explore freely—

can be a major weakness for some The lack of

restric-tions and navigation guides forces users to make their

own choices from a huge number of Web offerings; the

inexperienced, immature, impulsive, easily distracted, or

learning disabled may be challenged, even overwhelmed

At the same time, the opportunity to seek out related but

peripheral information, to pursue an interesting detail,

WBT’S CHALLENGES

Web-based training, as an innovation, presents lenges: different roles and responsibilities for instructorsand trainees; changes in teaching methods; the impor-tance of provision for individual differences; and newfinancial and economic realities

chal-New Roles

Web-based training creates changes in the ways traineesconnect with the trainer, the content, and the learningsystem As described below, because WBT allows shift-ing of place and pace of learning, roles change; the fo-cus is on the trainees’ skill development, and the tutor

or trainer consequently becomes less the “sage on thestage” and more a “guide on the side” (Burge & Roberts,1993) Similarly, if permitted, equipped, and disposed to

do so, trainees may assume more responsibility for theirown learning, including accessing outside materials andcommunicating as needed with the trainer and with othertrainees Overall, successful WBT changes trainees’ expe-riences, providing greater individualization, making fea-sible conveniences such as self-pacing, on-demand review,acceleration, and practice testing, and providing readylinkages to other people and resources

As the early pioneers of technology-based trainingfound, the quality and completeness of the learning mate-rials are critically important, as are the appeal, intuitive-ness, and stability of the delivery system Team develop-ment, combining subject-matter experts (SMEs), graphicsartists, learning specialists, designers, programmers, andmanagers, should make the development process moreefficient and productive This view assumes awareness ofanother lesson taught by the pioneers: that technologyper se does not automatically change the trainees’ experi-ences, but careful instructional design, quality materials,flexible delivery, timely tutor help, and convenient com-munications systems may

Because of these differences, trainers in Web-based vironments may find their duties and priorities changed

en-A study (National Education en-Association, 2000) of U.S.college instructors in a variety of institutions found thefollowing:

rMost reported Web-based teaching was more personally

rewarding than traditional methods: distance methodswere seen as giving trainees better access to informa-tion, better quality materials, more help in masteringthe subject matter, and more allowance for individualneeds

rMost instructors had at least some one-on-one contact

with learners, and those who had reported higher levels

of satisfaction in their teaching

rTeaching at a distance required more instructor time;

unfortunately, most training organizations did not mally recognize this fact

for-WBT’ S C HALLENGES 665

rDespite lack of organizational recognition of the greater

time required, almost three-quarters of the surveyrespondents held positive feelings about distance teac-hing (only 14% reported negative feelings)

The WBT Environment

As noted, if designed to do so, and if the trainer supports

the shifts implied, WBT can change the basic relationship

between the trainee and the tutor, and can alter

funda-mental characteristics of the training environment:

out-side information resources and a wider range of human

contacts can be accessed; there are more choices and

op-tions for trainees (but trainees need greater maturity to

exercise them wisely); and WBT environments can

em-phasize collaboration over competition (Relan & Gillani,

1997) Materials design, instructional methods, and “best”

teaching practices are also affected in WBT

environ-ments

Materials and Instructional Activities

In traditional face-to-face teaching, instructional

mate-rials may be prepared at the last minute, or even

sim-ply dispensed with (trainees being required to take notes

from the comments and often random chalkboard

mus-ings of the instructor) In WBT, materials preparation is

a major stage in program development Complete WBT

materials are self-contained, including organizers and

in-structions, with guidance and feedback provided through

embedded questions and other self-evaluation activities

Support and orientation are available for any technologies

used

In well-designed and -managed WBT, instructional tivities and materials may employ some or all of the fol-

ac-lowing principles:

Typically, a wider range of resources, some from outside

the local environment, is used

Training may incorporate experiential learning and

sim-ulations, accessed via Web links

Collaboration replaces competition

The instructor is more a guide and coach than a dispenser

of information

Problem- or case-based learning is more common,

some-times increasing the training’s realism and ity (Students are permitted, even required, to clarifyand refine questions themselves, without constant re-liance on the trainer.)

authentic-Personal knowledge and experience are valued and

in-cluded in problem-solving activities (Newby, Stepich,Lehman, & Russell, 2000)

“Best Practices” in WBT

Instructors in well-planned WBT adopt specific

ing strategies known to enhance learning One

train-ing model recommends trainers strive for a balance

be-tween interpersonal rapport and intellectual excitement,

requiring the trainer to be interpersonally warm, open,

predictable, and learner-centered, while also being clear

and enthusiastic about the training content (Lowman,

1994)

Another well-respected model of best practices mends these training behaviors (Chickering & Gamson,1989):

recom-Encourage contacts between trainees and instructors.Develop reciprocity and cooperation among trainees.Use active learning techniques

Give proper and timely feedback

Emphasize time-on-task

Communicate high expectations

Respect diverse talents and ways of learning

Bloom’s (1984) classic description of the “alterablevariables” of learning also provides guidance for Web-based trainers Research in mastery learning showedthat the following variables, when emphasized, producedlearning outcomes similar to what could be achieved un-der ideal training conditions (one-to-one tutorial):Provide well-designed tutorial instruction

Give timely reinforcement

Give appropriate and sensitive corrective feedback.Provide cues and explanations, as needed

Encourage learner classroom participation

Assure trainees make effective use of time on task.Help trainees improve reading and study skills, as re-quired

Individual Differences

One of the major differences between Web-based andmore traditional forms of training is WBT’s capacity foraccommodating the individual expectations and prefer-ences of trainees This feature can be particularly valu-able in meeting “special” needs, or those based upon adult

trainees’ personal and situational variables Personal

vari-ables include age, maturity, personal health, time ability (and management skills), motivation, previouslearning, financial circumstances, and life and develop-mental stages Situational variables include factors such

avail-as location (related to the location of any required based training), admission and training program require-ments, availability of counseling and advisement services,and personal issues such as transportation, health, andchild-care (Cross, 1981)

site-WBT’s capacity to accommodate differences effectivelypartially depends upon the trainees’ capacity and will-ingness to exercise independence, autonomy, and self-direction Even if trainees are adults or mature adoles-cents, the presence of the needed skills and maturity forself-directed learning cannot always be assumed Traineesmust be willing to exercise self-direction and indepen-dence in learning

Problems arise in WBT situations when there is a match between the self-direction the learning system per-mits and the expectations of the trainees Mismatches

mis-between teaching or training style and learning style can

result in dissatisfaction with the learning experience, orworse (dropout, failure) Programs are more success-ful if aligned with the developmental stages of individ-ual learners Trainee readiness may range from nearly

align with trainees’ expectations for support, interaction,

or recognition may be one of the principal reasons for

unacceptably high dropout rates in some WBT programs,

a problem which, though hard to describe on a national

basis, has been identified as a serious one for some online

training (Frankola, 2001)

Economic Factors

The economics of WBT, though changing rapidly in the

details, continue to directly impact training providers and

consumers

For Providers

Costs of development of WBT vary dramatically

Text-based WBT, involving conversion of existing material and

using one of the many authoring tools available, may

be economically accomplished by a subject-matter expert

(SME) with basic instructional design skills On the other

hand, development of an hour of computer-assisted

learn-ing (CAL) uslearn-ing high-level authorlearn-ing languages might

re-quire 40 to 150 hours (Szabo, 1998), and one complex 4- to

6-hour multiunit module in weather forecasting,

incorpo-rating multimedia and simulation effects, reportedly

re-quired a year, involved a team of instructional design and

subject matter specialists, and ultimately cost $250,000

(Johnson, 2000) Financial considerations are primary in

most WBT implementations: if an organization cannot

af-ford the attendant costs (especially the often heavy initial

investment in development), it may not be able to make

the transition to WBT, even if the need is clear and the

organization willing

The financial case for WBT depends largely upon the

relation of fixed to variable costs of development and

de-livery Fixed costs are those incurred whether the training

materials serve a handful or thousands of users Fixed

costs include staff salaries, equipment, and other

capi-tal costs directly related to development, including rent

and other overhead costs Variable costs are those that

increase in relation to demand, such as printing,

materi-als reproduction, and shipping; wages of section lecturers

or lab demonstrators hired in response to registrations;

additional clerical assistance; costs for licenses or

copy-right based on usage; and equipment for training delivery,

which might have to be acquired to serve increasing

de-mand In WBT development projects, financial viability

often depends upon fixed costs being kept to a minimum,

and as many costs as possible remaining variable

(depen-dent upon, and thus paid for, by demand)

Providers of WBT must promote their programs and

services without overselling them While WBT offers

the potential for substantial convenience increases and

improvements in efficiency (including reduced training

costs), it is important to acknowledge that WBT results

cannot be guaranteed to be uniformly or automatically

better for all users This is due to interactions among

economic, technical, and organizational factors, and

be-cause of the importance of the design to the quality of

to achieve economic benefits from technology mentations, while others made impressive gains, mainlythrough enhanced performance compared to the compe-tition (Fahy, 1998) Nevertheless, where design convergesadvantageously with needs, opportunities, and a willingcorporate culture, WBT has been proven successful (Vaas,2001; Welsch, 2002)

imple-For Consumers (Trainees)

WBT trainees have come to expect that they will have cess to timely, economical, high-quality, self-paced train-ing, virtually anytime and anywhere (Vaas, 2001) The

ac-keys to meeting these expectations are the cost and

acces-sibility of the WBT technologies used (Bates, 2000), and

relevance of WBT’s interaction capabilities to specific userneeds (Fischer, 1997)

For trainees with “special” learning needs, WBT’s teraction capabilities can provide important advantages.The mobility-handicapped, those with learning disabili-ties (LDs), or attention-deficit disorders (ADDs), includingADDults (Keller, 1999), often find an environment withmore learner controls, such as is typically found in WBT,helpful Two core features of WBT directly applicable tospecial needs trainees include

in-rStructure—Advance organizers; clearly stated

objec-tives, schedules, and timelines; embedded sion checks; integrated media under learner control;multimodal presentations; user-accessible performancerecords and reports; and communication links with thetrainer and other support resources

comprehen-rFlexibility—Any place, any pace access.

For the physically handicapped or mobility impaired,the following features and characteristics of WBT can be

of value:

rDistributed—Available in accessible locations.

rInterruptible—Trainees can take breaks when needed.

rModular—Single or multiple skills can be addressed.

rMultisensory—Sight, sound, and tactile cues can be

in-corporated

rNonlinear—Presentation sequence can be varied.

rPortable—Easily moved or transferred.

rResponsive—Adoption time is relatively short.

rTransferable—Crosses cultural, language, situational,

physical, and geographic barriers (Gerofsky, 1998).Those working with special needs audiences havethe capability to monitor progress regularly (includingadministering testing as needed), communicating withtrainees easily, allowing trainees to communicate witheach other (socialize), and helping coordinate and sup-port training components (including the efforts of helpersand support staff)

Trainees without special needs can benefit from WBT,too; many of the above features can assist most trainees

T HE F UTURE OF WBT 667

to complete their training with more satisfaction or

less stress, by reducing potential conflicts with trainees’

careers and personal lives Experience has shown that

training may precipitate problems among trainees in

gen-eral, which skillful use of WBT’s own communications

capabilities may help solve, such as

rFeelings of inadequacy at the sheer amount of material

to be covered;

rDelays in receiving feedback or answers to questions;

rKeeping up with the variety of discussions and

interac-tion often present in online (computer-mediated munications, CMC) discussions;

com-rAdjusting to the absence of visual clues in group

rela-tions; and

rFatigue and health problems arising from reliance on

unfamiliar technologies (eye-strain or posture problems

at the computer, for example)

THE FUTURE OF WBT

While WBT has proven its potential value for training

delivery, there are barriers that may restrict or slow its

expansion, chiefly bandwidth availability, security and

privacy issues, and user access to required technologies

Bandwidth and Security

Present “POTS” Systems

Today, most home Web users still access the Internet

us-ing POTS (plain old telephone system) dial-up modems

While common, cheap, and reliable, the transfer speeds

available with this technology are a limiting factor in the

evolution of multimedia-based WBT

Typical POTS Internet connections move data ically; actual rates are always lower) at 56 Kbps (kilobits

(theoret-per second); at the higher end of the bandwidth

spec-trum are speeds of 1,000 to 1,500 Kbps (cable, DSL, ISDN,

T-1), and some that exceed 2,500 Kbps (RADSL, T-3) To

compare these speeds with actual requirements of a

com-mon medium, TV graphics (depending upon the screen

resolution of the receiver) require throughput of from

1,800 to over 110,000 kilobits of data per second None of

the current POTS- or cable-based transmission methods

are capable of more than a small percentage of that rate

Considerably less than full TV-quality video could beadequate for many WBT applications However, training

organizations appear to be ignoring this fact: a survey of

the intentions of U.S colleges and universities showed

that, between 1995 and 1998, 2-way video use grew 22%,

while many of those institutions that had not yet

commit-ted to it were planning to do so within 3 years On the other

hand, use of audio-only delivery (in the forms of one-way

audiotapes, or two-way teleconferencing or VOIP [Voice

over Internet Protocol; Internet audio] connections),

po-tentially very powerful and relatively low-cost media,

re-mained virtually unchanged at about 10% of institutions

(U.S Department of Education, 1999) A similar focus on

high-bandwidth applications was found in the private

sec-tor: a 2001 survey showed that “live video” was expected

to grow from 7% to 31% in the next year (“Real-time help,”

2001)

Satellite Systems

Satellites provide a powerful alternative to ground-baseddata transmission in WBT systems: satellite-based signalscan be broadcast over a much wider area than broad-cast tower-based or independent wire/cable transmission.All the usual production costs apply to satellite-based de-livery; in fact, production costs may be higher, since thegreater potential audience may warrant the highest pro-duction values In addition to the costs of developing andlaunching the satellite the potential for equipment failure

is significant, given the inconvenience of service calls

At present, broadcast delivery systems, including lite, are federally regulated in North America, but if dereg-ulation of these services occurs, cable TV and telephonesystems will be able to compete to deliver each other’sservices (as they already do in other parts of the world).The impetus for deregulation is the fact that video andaudio signals, when digitized, are simply data, which can

satel-in prsatel-inciple (if not yet satel-in law) be delivered by anyone withdata transmission capabilities

Wireless Systems

Wireless technologies (other than satellites) are alsochanging rapidly, with direct implications for training.The cost of installing “fixed” wireless capabilities (theshort-range 802.11 protocols) in existing buildings hasfallen below the cost of wiring (or rewiring) Besides costsavings, wireless technologies are quick to install, and arehighly portable, so they can be readily moved as opportu-nities or demands change Portability also permits culti-vation of users by making equipment and services quicklyavailable to those best prepared to make good use of them(McKenzie, 1999) In late 2001, 7% of colleges and uni-versities in the United States had campus-wide wirelessinstallations, and 51% of institutions reported some wire-less capabilities, up from 30% in 2000 (Campus Comput-ing Project, 2001) The cost and availability of other types

of wireless technologies with much wider coverage areas,such as cell phones and IM (instant messaging) devices,are also dropping, though the training capabilities of thesetechnologies have not yet been widely tested

Despite cost reductions, wireless systems in traininghave some major disadvantages: transmission speeds aretypically slower; interference may lead to transmission er-rors, further reducing speed, especially if other electronicsoperate in the same environment; range depends upon thesite layout and configuration of the network; and (as dis-cussed later) wireless systems are much more vulnerable

Income was also associated with Web access: families

with annual incomes over $75,000 were three times

more likely to be online than those with incomes

be-low $24,000

Urban access rates were more than 12% higher than

non-metropolitan rates

The presence of a child in the family increased the

like-lihood of both computer ownership (by almost 22%)

and Internet access (by over 16%)

Age was a major factor: the group most likely to own a

computer and be connected to the Internet was aged

25 to 44 (ownership, 61.0%; Internet, 50.2%), followed

by the cohort aged 45 to 64 (56.9% and 46.7%,

respec-tively); least likely was the 65 and older group (at 24.3%

and 17.7%) In Canada, similar patterns were found

(“Getting connected,” 1999)

Gender has historically been an issue in Web access,

though experience with WBT appears to considerably

re-duce, and may even be reversing, former access patterns

(Wark, e-mail, September 26, 1999) Traditionally, men

have been more engaged generally with all aspects of

com-puter use than women; women have reported finding CMC

less personal and online environments less comfortable

than face-to-face interaction, and have consequently been

more reluctant to enroll in computer courses (Blocher,

1997; Kirkpatrick & Cuban, 1998)

The Internet may be about to change that pattern: since

May 2000, trends have shown that women as a group

ex-ceeded the number of men online, so that by June 2001

women comprised 40.9 of Internet users and men 39.8%

Interestingly, in relation to the question of the

feasibil-ity of the Internet for the training of older workers and

women, the largest increase in usage was among

indi-viduals over age 35, including women in that age group

Even women who were mothers increased their Internet

use: mothers who were online averaged 16 hours 52

min-utes per week, more even than online teens (who averaged

just over 12 hours weekly) Another fact with training

im-plications: mothers who might be expected to have the

least free time (single mothers and those with 3 or more

children) were online the most, averaging about 20 hours

per week, 20% more than the overall average (Saunders,

2002) While women as a group were increasing usage

sig-nificantly, men continued to lead women in frequency and

intensity of Internet use: when online, men averaged 16%

more time online than women, viewed 31% more pages,

and logged-on 11% more often (Pastore, 2001)

Assuring Security and Privacy

WBT systems may be victimized from the outside by

viruses, unauthorized intrusions, sabotage, or fraud It is

sobering that 75% of security breaches in the private

sec-tor (incidents of sabotage, hacking, or data theft) are

com-mitted by the institution’s own personnel (unauthorized

present employees or former staff) Wireless operations

ubiquitous and are expected to grow in number By oneestimate, in 2001 viruses were found in 1 of every 300e-mail messages; at the current rate of proliferation, by

2008 the ratio will be 1 in 10, and by 2013 it will be 1 in

2 (“Outbreak,” 2001) “Virus” is the generic name for allmalicious programs, including worms and Trojan horses;

the term malware has been suggested for all these

mali-cious forms of code (Seltzer, 2002) Worms and Trojansare special forms of malware, in that they programmed tospread by themselves without human intervention (usu-ally by e-mail), while simple viruses require individuals todeliberately share files for the viruses to be able to movefrom machine to machine The magnitude of the threatfrom malware has led most organizations to install pro-tection in the form of virus detectors and firewalls As well

as preventing unauthorized intrusions from the outside,the latter restrict the access of those behind the firewall

to outside people and materials (for example, VOIP may

be impossible, or severely limited) While protecting thesecurity of those behind them, firewalls can constitute amajor barrier to WBT generally

Confirming the identity of trainees is also a potentialproblem in WBT, especially if trainees do not routinelymeet face-to-face with instructors Just as failure of sys-tem security might expose a training organization to em-barrassment, expensive down-time, or even litigation, fail-ure of an organization’s screening and monitoring systemsleading to a fraudulent registration, award of credit, orgranting of a credential might be disastrous for its rep-utation Fortunately, technologies exist and are becom-ing more economical to help with trainee identificationand authentication: biometric devices such as voiceprintand fingerprint identifiers, and remote cameras, have re-cently become available for economically checking iden-tities of trainees and supervising remote testing events(Miller, 2001)

Implementing WBT

In order to produce high-quality WBT results, rating flexibility, efficiency, and individualization, train-ing organizations must assure that certain elements arepresent Among these are a conducive social learning envi-ronment and institutional collaboration to assure efficientprovision of courses and transfer of credit, including priorlearning assessment

incorpo-Cohort Learning and Socialization

All group learning is social WBT technologies provide theoption for interaction and collaboration, which should inturn increase “social presence” (Garrison, 2000) and re-duce “transactional distance” among participants (Moore,1991)

Cohort-based WBT provides a supportive social work, especially for adult trainees who may lack confi-dence or who may face hurdles in returning to formallearning Cohort-based programming uses more active,

net-T HE F UTURE OF WBT 669

cooperative, and collaborative learning strategies than

more traditional methods The cohort structure consists

of a group of trainees who enter and complete the program

together in a predetermined and prescheduled series of

common training experiences Trainees may meet

face-to-face occasionally, even in primarily distance programs, to

initiate social interaction that technology-based

interac-tion can then sustain The resulting training, though

lock-step, appears to be successful in creating trust,

empower-ment, and support, while reducing adjustment problems

and drop-out, especially among older trainees (Saltiel &

Russo, 2001, p vii)

The communications capabilities of WBT technologiescan also reduce isolation, and increase motivation and

social interaction Computer-mediated communications

includes one-on-one interaction (e-mail), one-to-many

connections (conferencing, list-servs), data sharing (file

attachments), and information access (via the Web’s

links) Computer conferencing is a potentially powerful

means of creating community in WBT programs CMC

may increase comprehension of training objectives by

promoting peer-to-peer interaction, but basic

ground-rules enforced by a conscientious moderator are required

to assure that the resulting CMC interaction is effective,

and to help avoid asocial outcomes such as “social

loafing.” (Other forms of asocial interaction, such as

rudeness or “flaming,” are rare in moderated training

interactions, but may occur in public nonmoderated

environments such as list-servs.)

Institutional Collaboration

WBT assists trainers to address the globally recognized

need for more efficient and flexible training delivery,

in-cluding transnational standards, increased quality

assur-ance (based on competency-based curricula), multiskill

training, and the appropriate adoption of electronic

tech-nologies to increase trainee success Driving this is the

fact that employers have historically not been very

satis-fied with what they perceive as the public school system’s

inflexibility, and apparent inability to prepare its young

graduates better for employment

Employers expect graduates to be capable of work, creativity, problem solving, and adaptability To

team-counter the lack of flexibility in institutional training,

some employers advocate training-on-the-job (TOJ)

pro-grams TOJ is seen as providing a better training

experi-ence overall, especially if linked with WBT opportunities

The combination has been regarded as better addressing

employees’ convenience and privacy, while allowing

em-ployers to monitor relevance, and permitting the

involve-ment of experienced employees in the training of novices

(Conference Board of Canada, 2001)

Prior learning assessment (PLA), like transfer credit,benefits trainees who have accumulated credits over time,

perhaps from a variety of sources, without ever

complet-ing a credential PLA recognizes that learncomplet-ing may

ap-pear to be haphazard, while yet equipping the trainee

with skills and knowledge worthy of formal recognition

(especially if accompanied by relevant work experience)

WBT may help a trainee integrate and complete a

pro-gram based on PLA credits, a process sometimes called

Figure 1: Diagram attributed to Coldeway by

Simon-son, Smaldino, Albright, & Zvacek (2000, p 7) A similartypology is also found in Johansen, Martin, Mittman, Saffo,Sibbet, & Benson (1991, p 17.)

Media and the Future

Some technologies require broadband (simulations, motion video, high-quality audio); on the other hand,some technologies are useful only for relatively limitedtraining purposes (text on paper is ideal for informationtransmittal, but lectures and collaborative group sessionsare poor vehicles for this purpose) Research has demon-strated that the impact of technologies on training out-comes depends upon specific media characteristics, andthat technologies differ in respect to their cost, accessibil-ity, teaching implications and impacts, interactivity, user-friendliness and control, organizational impact, novelty tousers, and speed of adoption and adaptation (Bates, 2000).Knowing this, WBT programmers can make betterdecisions about the “right” technology for a particularapplication on the basis of the amount of separation (the

full-“distances”) between trainees and elements of their WBTprograms Figure 1 illustrates how time and place of train-ing can vary in WBT

Differences in the time and place of training can impacttrainees, and affect the flexibility of the training, in severalways:

Quadrant 1 (“same time, same place”) Training in this

quadrant is synchronous (same time) and site-bound

(a classroom or lab is set aside for it) Participants

in the same place at the same time may still ence “distances”—psychological, interpersonal, socio-cultural, linguistic, philosophical, etc.—which maycreate barriers to communication and learning, requir-ing timely trainer intervention

experi-Quadrant 2 (“same place, different time”) Training is based, but permits asynchronous access in the form ofcorrespondence modules or packages at a training orlearning center Regular attendance at the designatedtraining site is often required so progress can be mon-itored

site-“any pace, any place” training Requires the

train-ing institution to provide materials, support,

interac-tion opportunities, and administrative arrangements

at the trainees’ convenience Trainees require

appro-priate remote-access technologies

The Evolution of Present Media

Training media are changing as bandwidth improves, and

as they do, new forms of familiar technologies are

present-ing WBT designers with options and capabilities

previ-ously unavailable or not cost-effective Examples include

the previously mentioned VOIP, and reusable learning

ob-jects, with (for those capable of accessing it) multimedia

VOIP technology permits use of computers for voice

communications, either as person-to-person private

con-versations or in multipoint group sessions Users

com-monly require no more than normal dial-up access to

the Web, plus a sound card, microphone, and

speak-ers For video, VOIP typically provides a 2× 3display,

with a refresh rate dependent upon bandwidth (IP video

is presently not of full-motion quality; its jerkiness and

grainy nature lead some users to switch it off completely,

relying upon audio alone.) The quality of IP audio is

usu-ally adequate to good VOIP services are very cheap or

even free, and the quality and reliability are improving

rapidly

Standards and Reusable Learning Objects (RLOs)

Training materials are increasingly designed to be reused

(“repurposed”), as standards are developed by

organi-zations such as the Aviation Industry CBT Committee

(AICC), the Instructional Management Systems (IMS)

Global Learning Consortium, the Institute of Electrical

and Electronics Engineers (IEEE), and the Advanced

Dis-tributed Learning (ADL) Initiative of the Department of

Defense (developer of the Shareable Courseware Object

Reference Model [SCORM]) (Hodgins & Conner, 2000)

WBT instructional materials developed under RLO

stan-dards are portable, for maximum present and future

(re)use Metadata tagging of RLOs attempts to assure

sev-eral outcomes relevant to potential WBT uses:

rFlexibility—Material is designed to be used in multiple

contexts and to be easily reused in other applications

rEase of update, search, and content management—

Metadata tags allow quick updating, searching, and

management of content through sophisticated filtering

and selecting capabilities

rCustomization—Modular learning objects enable more

rapid program development or revision

rInteroperability—RLOs are designed to operate on a

wide range of training hardware and operating systems

rCompetency-based training—Competency-based

ap-proaches to training are promoted by RLOs; materials

are tagged to competencies, rather than subjects,

disci-plines, or grade levels

(Longmire, 2000) Multimedia RLOs must be used ingly, if at all, in training intended for home use, however:while in late 2001 92% of U.S businesses with 1,000 em-ployees or more reportedly had broadband connections(T1, T3, DSL, cable, ATM, frame-relay or faster), fewerthan 20% of home users had these capacities (Metz, 2001)

spar-The “New” Internets

Worldwide growth in commercial use of the public Webhas resulted in ongoing efforts to replace it with a versionreserved for academic and military use In North America,new Internet developments include the United States’Internet2, the Information Technology Research andDevelopment (ITR&D) Program, and Canada’s CA∗netsystem

Internet2 is a collaborative effort of more than 120 U.S.universities, partnering with industry and government(through the National Science Foundation) to create anenvironment that “is not clogged with music, commercialentities and porn” (Rupley, 2002) As with Canada’s CA∗net

II, CA∗net 3, and CA∗net 4 (launched in mid-2002), search and education are the focus (Networking, 2002b)

re-In mid-2001, the first implementations of re-Internet2 inU.S K–12 schools had commenced (Branigan, 2001), withpublic access available in early 2002

The Information Technology R&D Program ues and broadens the agenda of the NGI (Next Genera-tion Internet; NGI, 2001) project, a multiagency, feder-ally sponsored research and development program that,

contin-by the time it concluded in 2001, had helped achieve jor advances in networking speeds The ITR&D programincludes the collaborations of 12 very high profile agen-cies (for example, the National Science Foundation [NSF],NASA, the Defense Advanced Research Projects Agency[DARPA], the National Institutes of Health [NIH], and theEnvironmental Protection Agency [EPA], among others).The ITR&D program conducts research and development

ma-in various “program component areas” (PCAs), ma-ing cutting-edge projects in high-end computing, scalableinformation infrastructure, large-scale networking R&D,and high-confidence software and systems The commit-ment is significant: the budget requested for 2002 was al-most $2 billion (Furlani, 2002)

includ-The California Institute of Telecommunications andInformation Technology (http://www.calit2.net) consor-

tium plans to build a high-speed wireless network that is

cheap, always on, and accessible through a variety of nologies “Tether-free” online technologies are currentlyrepresented by palm-size computing and cell phone-typecommunications devices The evolutionary potential fortraining applications of these highly portable technolo-gies is seen as tremendous, assuming concurrent advances

tech-in AI (artificial tech-intelligence) systems and voice commandcapabilities Public funding for this project reached $300million in mid-2001 (Chapman, 2001)

CA∗net II, Canada’s first “next generation” Internet tiative, demonstrated that a dedicated, noncommercial

ini-G LOSSARY 671

research Internet was feasible and needed by Canadian

academics Although initially established as a public

en-terprise CA∗net II was privatized in 1993, then coming

under the direction and control of CANARIE (the

Cana-dian Network for the Advancement of Research, Industry

and Education), a consortium of private Canadian

orga-nizations and academic institutions

The purpose of the CA∗net program was to upgradeCanada’s research and development infrastructure, espe-

cially networking and communications capabilities, and

to permit joint ventures and collaborations to promote

the involvement of Canadian business and industry in

the knowledge-based economy Like the United States’

NGI and Internet2 systems, CA∗net uses “special access

points” in each Canadian province to provide access to

the system’s high-capacity, high-speed communications

link called the vBNS (very high-speed Broadband

Net-work Service), which in turn connects to the netNet-work’s

backbone

Canada’s CA∗net II system, the world’s first nation-widenetwork of its sort, was succeeded by CA∗net 3 (“Hooked to

all high-capacity networking systems, CA∗net uses

differ-ent wavelengths (colors) of light and fiber optics to

per-mit dozens of different transmission “channels” (CA∗net

II had only one) CA∗net 3 was some 20 times faster than

CA∗net II, and 50,000 times faster than present

commer-cial Internet services; CA∗net 4 is expected to continue this

evolution in high-speed networking, improving the

poten-tial for quality WBT (Networking, 2002a, 2002b)

CONCLUSION

Predicting the future for WBT is, on one hand, simple: it

will expand, grow, and become central to more forms of

future training worldwide That prediction is safe, both

because so much has already been invested in the

Inter-net delivery infrastructure and because the Web has

al-ready proven to be so effective in reducing direct training

costs, increasing access, and addressing serious skills

defi-ciencies in an increasingly competitive and technological

world

On the other hand, no one can predict, even a shorttime into the future, specific details of the training ad-

vances WBT will help make possible in the future Greater

usage does not imply standard use; more investment may

not result in quality increases; reliance on WBT does not

guarantee enthusiasm or success by specific groups of

trainees Experience with other forms of training

deliv-ery have demonstrated that instructional design, perhaps

even more than the medium, makes training effective, and

trainee support and overall relevance of the content make

it satisfying to users

While WBT cannot guarantee that future training willnot be pedestrian or inefficient, its potential strengths may

suggest how training of all kinds might be improved The

core elements of the Web as a training device—ubiquity,

accessibility, stability, supportiveness, redundancy, and

friendliness—are common to other successful teaching

environments For WBT to expand, developers, trainers,

trainees, and employers must see these aspects of the

Web as potential assets for their training programs If

the inherent features of the Web are seen as important

to training, continued growth and expansion of WBT arecertain to occur

GLOSSARYAsynchronous “Different time” (and often differentplace, i.e., the trainees’ workplace or home) trainingand communications interactions, made possible bytechnologies that collect messages and make themavailable at the convenience of the reader Examplesinclude e-mail, CMC, and list-servs

Attention deficit disorder (ADD) A form of learningdisability that, in children, results in short attentionspan and lack of focus, sometimes accompanied byhyperactivity; ADDults, adults with ADD

Bandwidth The capacity of a channel (for example, atelephone line or a coaxial cable) to carry data Highbandwidth permits multimedia (audio, video, anima-tion), while low bandwidth limits users to text or sim-ple graphics, and may preclude VOIP and other newinteraction tools

Computer-mediated communications (CMC) based, asynchronous communications, usually re-stricted by password to a designated group such as aclass or training cohort, and moderated to assure thatthe discussion stays on topic and is civil

Text-Internet The public network of linked computers sible by anyone with a Web browser

acces-Intranets Private computer networks that may or maynot also provide Web access, providing security andcontrol not available on the public Internet by limitingaccess and controlling the content available to users

Malware Any form of malicious code intended to infect

a computer or a network, including viruses, worms,and Trojan horse programs (Seltzer, 2002)

Metadata The identifying material added to RLOs topermit easy reuse or “repurposing.”

Online Training that includes potential for synchronous

or asynchronous electronic (often Internet-based) teraction between the trainee and the trainer, the train-ing materials, and other trainees

in-Prior learning assessment (PLA) A process intended

to result in the granting of credit toward a credential for

a trainee’s accumulated formal and nonformal ing experiences; recognizes and rewards the learning

learn-of individuals who have not been able to complete acredential at one institution in the normal way, due tocareer or personal reasons

(Reusable) learning objects (RLOs) Materials larized, packaged, and labeled to encourage catalogu-ing, access, and reuse in multiple contexts

modu-Synchronous “Same time” and (often) same place ing or communication interactions, e.g., face-to-facetraining

train-Training Instruction in psychomotor skills and edge primarily for practical purposes and relativelyimmediate application

knowl-Voice over Internet protocol (VOIP) The capability

of Internet-based programs to provide voice to-point or point-to-multipoint connections to any-one with a browser, a sound card, microphone, and

point-pus technical training, and elements of training or

professional development (PD) conducted primarily

face-to-face, but including some online components,

with the Internet or an intranet as the access/delivery

vehicle

CROSS REFERENCES

See Distance Learning (Virtual Learning); Internet Literacy;

Voice over Internet Protocol (IP).

REFERENCES

Bates, A W (2000) Managing Technological Change San

Francisco: Jossey-Bass

Blocher, M (1997) Self-regulation of strategies and

mo-tivation to enhance interaction and social presence

in computer-mediated communication Unpublished

Ph.D dissertation, Arizona State University

Bloom, B S (1984, June–July) The 2 sigma problem: The

search for methods of group instruction as effective as

one-to-one tutoring Educational Researcher, 4–16.

Branigan, C (2001, April 16) Five states are first to

of-fer Internet2 to schools eSchool News Online

Re-trieved June 2001 from http://www.eschoolnews.com/

showstory.cfm?ArticleID=2535

Briggs, L., & Wager, W (1981) Handbook of procedures

for the design of instruction (2nd ed.) Englewood Cliffs,

NJ: Educational Technology

Burge, E J., & Roberts, J M (1993) Classrooms with a

difference: A practical guide to the use of conferencing

technologies Toronto: University of Toronto (OISE),

Distance Learning Office

Campus Computing Project (2001) The 2001 National

Survey of Information Technology in US Higher

Education Retrieved May 2002 from http://www.

campuscomputing.net/summaries/2001

Chapman, G (2001) Consortium sets sights on a “new

Internet.” Digital Nation [online article and column,

Los Angeles Times, April 5] Available by listserv from

chapman@lists.cc.utexas.edu

Chickering, A., & Gamson, Z (1989, March) Seven

prin-ciples for good practice in undergraduate education

AAHE Bulletin, 3–7.

Conference Board of Canada (2001) Performance and

Potential 2001–02 Retrieved May 2002 from http://

Dick, W., & Carey, L (1978) The systematic design of

in-struction Dallas: Scott, Foresman & Co.

Fahy, P J (1998) Reflections on the productivity paradox

and distance education technology Journal of Distance

Education, 13(2), 66–73.

stitute and State University Retrieved May 2002 fromhttp://ei.cs.vt.edu/∼mm/

Frankola, K (2001) Why online learners drop out

Work-force Retrieved July 2002 from http://www.workWork-force.

com/archive/feature/22/26/22/index.phpFurlani, C M (2002) National IT R&D Program Retri-eved May 2002 from http://www.itrd.gov/about/presentations nco/2002/furlani nhpcc 20020403/index.php

Gagne, R., & Briggs, L (1979) Principles of

instruc-tional design (2nd ed.) New York: Holt, Reinhart and

Winston

Garrison, R (2000) Theoretical challenges for distanceeducation in the twenty-first century: a shift from

structural to transactional issues International Review

of Research and Open and Distance Learning (1)1.

Retrieved September 2000 from http://www.icaap.org/iuicode?149.1.1.2

Gerofsky, G (1998, May) An Athabasca challenge: ing for disabled learners at a distance Paper presented

Provid-at the 14th Annual CADE Conference, Banff, Canada

Getting connected, staying unplugged (1999)

In-novation Analysis Bulletin, 1, 4 Statistics Canada–

Catalogue No 88-003-XIE Retrieved March 2000 fromhttp://www.statcan.ca:80/english/freepub/88-003-XIE/free.htm

Glaser, R (Ed.) (1978) Advances in instructional

psychol-ogy Hillsdale, NJ: Lawrence Erlbaum.

Grow, G (1991) Teaching learners to be self-directed

Adult Education Quarterly, 41, 125–149.

Harapniuk, D., Montgomerie, T C., & Torgerson, C.(1998) Costs of developing and delivering a Web-based

instruction course In Proceedings of WebNet 98—World

Conference of the WWW, Internet, and Intranet

Char-lottesville, VA: Association for the Advancement ofComputing in Education Retrieved July 2002 fromhttp://www.quasar.ualberta.ca/IT/research/nethowto/costs/costs.html

Hauben, M (1994) History of ARPANET Retrieved April

2002 from http://www.dei.isep.ipp.pt/docs/arpa.htmlHodgins, W., & Conner, M (2000, Fall) Everythingyou always wanted to know about learning stan-

dards but were afraid to ask LiNE Zine Retrieved

June 2001 from http://www.linezine.com/2.1/features/wheyewtkls.htm

Hooked to CA∗net 3 (2000, March) University Affairs, 27.

Johansen, R., Martin, A., Mittman, R., Saffo, P., Sibbet,

D., & Benson, S (1991) Leading business teams Don

Mills, Ontario, Canada: Addison-Wesley

Johnson, V (2000, June) Using technology to train

weather forecasters T.H.E Journal Online

Re-trieved March 2002 from http://www.thejournal.com/magazine/vault/articleprintversion.cfm?aid=2880Jones, M., & Farquhar, J (1997) User interface design for

web-based instruction In B Khan (Ed.), Web-based

in-struction (pp 239–244) Englewood Cliffs, NJ:

Educa-tional Technology

R EFERENCES 673

Kaye, A (1989) Computer mediated communication

and distance education In R Mason & A Kaye

(Eds.), Mindweave (pp 3–21) Toronto: Pergamon

Press

Keller, F S (1968) Goodbye, teacher! Journal of Applied

Behavioral Analysis, 1(1), 79–89.

Keller, V (1999) Adaptation and application of a

tran-script analysis tool to analyze a computer-mediated communication (CMC) distance education course tran- script Unpublished master’s thesis, Athabasca Univer-

sity, Athabasca, Alberta, Canada

Kirkpatrick, H., & Cuban, L (1998, July–August) Should

we be worried? What the research says about der differences in access, use, attitudes, and achieve-

gen-ment with computers Educational Technology, 56–

61

Leiner, B., Cerf, V., Clark, D., Kahn, R., Kleinrock, L.,

Lynch, D C., Postel, J., Roberts, L G., & Wolf, S (2002)

A brief history of the Internet Retrieved May 2002 from

http://www.isoc.org/internet/history/index.shtmlLongmire, W (2000, March) A primer on learning ob-

jects Learning Circuits Retrieved June 2001 from

http://www.learningcircuits.com/mar2000/primer.htmlLowman, J (1994) What constitutes masterful teaching

In K Feldman and M Paulsen, Teaching and learning in

MA: Simon & Schuster

Mager, R (1975) Preparing instructional objectives (2nd

ed.) Belmont, CA: Fearon

McKenzie, J (1999) Strategic deployment of hardware

to maximize readiness, staff use and student

achieve-ment From Now On, 8(8) Retrieved August 2000 from

Moore, M G (1991) Editorial: Distance education theory

American Journal of Distance Education, 5, 1–6.

National Education Association (2000) A survey of

tradi-tional and distance learning higher education bers Washington, DC Retrieved August 2000 fromhttp://www.nea.org/he/abouthe/distance.html

mem-Networking (2002a) $100 million in federal budget

for CA∗net 4 Networking, 6 (1) Retrieved May 2002

from http://www.thenode.org/networking/january2002/

briefs.html#1Networking (2002b) CA∗net 4 coming down the pipe Net-

working, 6(5) Retrieved July 2002 from http://www.

thenode.org/networking/may2002/briefs.html#1Newby, T., Stepich, D., Lehman, J., & Russell, J (2000)

Instructional technology for teaching and learning (2nd

ed.) Upper Saddle River, NJ: Merrill

NGI (2001) Next Generation Internet (NGI)

Initia-tive Retrieved March 2003 from http://www.ngi.gov/

sc99/fast facts.html

Outbreak (2001) PC Magazine, 20(21), 30.

Pastore, M (2001) Women maintain lead in Internet

use Retrieved July 2002 from http://cyberatlas

internet.com/big picture/demographics/article/0,,5901786791,00.html

Piaget, J (1952) The origins of intelligence in children

(trans.) New York: International Universities Press

Real-time help (2001) PC Magazine, 20(6), 73.

Relan, A., & Gillani, B (1997) Web-based instruction andthe traditional classroom: similarities and differences

In B Khan (Ed.), Web-based instruction (pp 41–46).

Englewood Cliffs, NJ: Educational Technology

Rupley, S (2002) I2, near you PC Magazine, 21(4), 21.

Rutherford, S., Patrick, J., Prindle, L, & Donaldson, S.(1997) Computer-managed learning (CML), an intro-duction Edmonton, Canada: Grant MacEwan Com-munity College and Northern Alberta Institute ofTechnology

Saettler, P (1990) The evolution of American educational

technology Englewood, CO: Libraries Unlimited.

Saltiel, I M., & Russo, C S (2001) Cohort programming

and learning Malabar, FL: Krieger.

Saunders, C (2002) Moms, Hispanics increasingweb use Retrieved July 2002 from http://cyberatlas.internet.com/big picture/demographics/article/0,,59011041581,00.html

Seltzer, L (2002) Personal antivirus PC Magazine,

21(11), 96–103.

Simonson, M., Smaldino, S., Albright, M., & Zvacek, S

(2000) Teaching and learning at a distance Upper

Sad-dle River, NJ: Merrill

Skinner, B F (1971) Beyond freedom and dignity New

York: Bantam Books

Suppes, P (1978) The role of global psychological

mod-els in instructional technology In R Glaser (Ed.),

Ad-vances in instructional technology (Vol 1, pp 229–259).

Hillsdale, NJ: Lawrence Erlbaum

Szabo, M (1998) Survey of educational technology

research The Educational Technology Professional

Development Project (ETPDP) Series Edmonton,Alberta, Canada: Grant MacEwan Community Collegeand Northern Alberta Institute of Technology

Thorndike, R L (Ed.) (1971) Educational measurement.

Washington, DC: American Council on Education

U.S Census Bureau (2001) Home computers and

Inter-net use in the United States: August 2000 Retrieved

July 2002 from http://www.census.gov/prod/2001pubs/p23–207.pdf

U.S Department of Education, Office of Educational

Re-search and Improvement (1999) Distance education

at postsecondary education institutions Retrieved April

2002 from http://nces.ed.gov/pubs2000/2000013.pdf

Vaas, L (2001) The e-training of America PC Magazine,

20 (22), ibiz1–ibiz4.

Wagner, E (1994) In support of a functional definition of

interaction American Journal of Distance Education, 8,

6–29

Warren, A., Brunner, D., Maier, P., & Barnett, L (1996)

Technology in teaching and learning London: Kogan

Page

Welsch, E (2002) Cautious steps ahead Online Learning,

6, 20–24.

Introduction 674

Reasons for Using Webcasting and

Significance of Webcasting to the Internet

Technical Standards and Protocols

State of the Radio Webcasting Industry 682

State of the Television Webcasting Industry 682

Major Players in the Webcasting Industry 683

Problems and Issues in Webcasting 683Cost of Digital Content and Copyright Issues 683Competition for Audience with Offline

Webcasting is the delivery of media contents and any

digi-tal information in various formats such as texts, graphics,

and audio and video files on the World Wide Web to

In-ternet users This definition states the two characteristics

of webcasting:

(1) The recipients of webcasts must have Internet access

to receive the content

(2) The content of webcasts can range from simple text to

rich media files with multimedia capabilities

Webcasting includes unicast (which serves a multimedia

file in real time to a single user) and multicast (which

al-lows many users to receive the Internet data streams at the

same time with special software and hardware installed

at different connections on the Internet)

There are many other terms commonly used to refer

to webcasting as well For example, cybercasting is

synonymous with webcasting Another common term is

Internet radio or Web radio However, Web radio refers

to one type of webcasting that uses a radio station format

and provides primarily audio files Some of the Web radio

stations only broadcast on the Internet, while others

broadcast content from their offline radio station

counter-parts Apart from audio content, Internet radio stations

display texts and visuals such as photos of the show hosts

and the playlist of the show Several sites such as Yahoo!’s

Launch (http://launch.yahoo.com/), flip2it.com (http://

www.flip2it.com/schedule.asp?webcaster), Angelfire

Ra-dio (http://www.angelfireradio.com/search.html), and

Classical Live Online Radio (http://www.classicalwebcast

com/start.htm) provide listings of Internet-only webcasts

Reasons for Using Webcasting and Significance of Webcasting to the Internet and E-commerce World

Webcasting offers many benefits to individuals and nizations that need to disseminate information and con-tent The interactivity of computers allows the personal-ization and customization of information to consumerswith great ease Webcasting can deliver contents to themass audience via the Internet and also to targeted audi-ence via an intranet, an extranet, or on a subscription ba-sis on the Internet In addition, the Internet can transmitcontents instantly to anywhere with Internet access, and

orga-if only nonmultimedia content is being webcast, the cost

of webcasting is generally lower than the cost of a sion or radio broadcast Video webcasting, however, can

televi-be an expensive proposition televi-because of the large serverspace and bandwidth required The program length, au-dience number, and transmission speed determine howmuch server space and bandwidth are needed The cost ofdelivering one 30-minute video webcast to 100,000 peoplecan run from US$12,500 for a live webcast and US$9,500monthly for an on-demand webcast This price does notinclude the costs of overhead, production, promotion, andmarketing involved to make a webcast successful.Mass media, businesses, and individuals who want tohave voices on certain issues and provide electronic mediacontent to a geographically diverse audience use webcast-ing as an alternative content delivery medium To estab-lished media such as broadcast and cable TV networks,webcasting means opening the battlefront to another newmedium against competitors and increasing the value oftheir media content Webcasting also means less reliance

on intermediaries such as cable system operators or localbroadcast TV stations (Ha and Chan-Olmsted, 2001) To

674

E XAMPLES OF W EBCASTING 675

radio stations and broadcast TV stations, which are

ba-sically local operations, webcasting means the

disappear-ance of geographic coverage barriers To newspapers and

other print media, their provision of webcasting

trans-forms their status to a multimedia content provider

To companies, webcasting opens new doors to howtraining is conducted and information is shared Instead

of restricting the training to a particular time at a

partic-ular location, employees can retrieve training materials

such as demonstration videos and conference sessions at

their own office or home at a convenient time Current

and prospective customers can retrieve product

demon-stration videos, virtual company tours, and other

interac-tive multimedia content about a company and its products

or services at their fingertips As more and more

compa-nies use an intranet (internal Web sites) to transmit their

webcasts, the reliability of the service greatly improves

The Yankee Group, a research firm, projected that

com-panies will spend up to $5.9 billion on online videos by

2005 (Vonder Haar, 2002) The primary function of online

videos is for advertising and marketing purposes (53%)

Corporate communications, employee training, and sales

training are other business functions of online videos

Financial services companies also use webcasting tocommunicate with investment advisors For example,

Safeco, a Seattle-based mutual fund, produces 40

web-casts a year for 5,000 investment advisors who

rec-ommend Safeco funds and portfolios to clients These

webcasts feature interviews with portfolio fund managers

every quarter to explain the different Safeco funds’

in-vestment strategies (Vonder Haar, 2002) Webcasts can

become an important customer relation management tool

that will substitute for meetings and conferences that are

complex to arrange and cost much more

Webcasting is also a means for international nonprofitorganizations to disseminate information to developing

countries For example, the World Bank Institute recently

launched B-SPAN, an Internet-based broadcasting

initia-tive B-SPAN will provide regular broadcasts of World

Bank events through webcasts over the Internet The

web-casts feature some of the world’s leading experts and

prac-titioners in the financial, poverty, health, education, legal,

environmental, and energy fields on the latest

develop-ments in their sectors

To individuals who would like to create media contentsand establish their own voices in the society, webcasting is

an ideal medium Not only is there no license requirement

for the content provider, the cost of distribution to a

geo-graphically diverse audience is much lower than any

tra-ditional mass media, making the dissemination of media

content for special interest and small audiences

afford-able In addition, there is no censorship of media content

on the Web (with the exception of some countries such as

China) and the reach of the Internet can be global

Dis-sidents and minorities will find the Web the best place to

broadcast views suppressed by the mainstream media

Webcasters have four strategic business revenuesources:

(1) The subscription and pay per service model, which

provides access to previously aired content or live tent;

con-(2) The broadcast advertising sponsorship broadcastmodel, which offers companion content to supple-ment current on-air programming and displays adver-tising during the webcast;

(3) The e-commerce model, which sells products andcomplementary items on the Web; and

(4) The syndication model, which creates and distributesoriginal digital media content to other webcasters

Webcasters must choose one or a combination of revenuesources above to sustain or make profits from their web-casts

EXAMPLES OF WEBCASTING

American Broadcasting Company (ABC), one of the bigthree U.S broadcast TV networks, is webcasting part of itsnews content on its ABCNEWS.com site ABCNEWS.comdistributes both daily TV news content and past ABC Newscoverage on the Web via Virage’s Internet Video Applica-tion Platform and Syndication Manager It indexes and

publishes searchable video clips from Nightline and World

News Tonight and on ABCNEWS.com Its news clips are

also distributed to affiliates, news agencies, schools, and

any other applicable Web sites (Digital TV, 2001) Its

busi-ness model is primary a subscription model Access to thebasic Web page is free However, additional news videoand interview clips are served as premium content, whichrequires a monthly subscription fee of $4.95 It also part-ners with Real Network’s RealOne SuperPass package asone of the program services offered to the package sub-scribers

Real Network’s RealOne SuperPass (Figure 1) is an ample of a successful webcasting business model usingsubscription as the source of income (Schlender, 2002).According to Lisa Amore, the spokesperson for Real Net-works, it has attracted 750,000 subscribers at the time

ex-of writing (personal communication, August 9, 2002) Itsservice is similar to a cable TV system’s carriage andcharges customers by subscription The basic level sub-scribers pay a monthly subscription fee of $9.95 to re-ceive 15 channels of news, sports, popular culture, andweather; 51 commercial-free radio stations; and an ad-ditional $10 to get legal digital music download service.The RealOne service provides a multimedia user interfacefor the Web In one window, it delivers exclusive stream-ing audio and video content from its content providerssuch as Cable News Network (CNN) and Fox Sports; inadjacent windows, RealOne displays information of com-panion Web sites and other explanatory materials Thecontent providers share the revenue of the subscriptionwith Real Network

A webcasting service based on the broadcast tising sponsorship model is OurMaine.com (Figure 2).This webcasting is a collaborative effort between WPXT-

adver-TV of Portland and WPME-adver-TV Visitors to the site canopen streaming video clips with the news of the day.Some streaming content is picked up from other Fox Net-work affiliates to supplement locally produced materials.The station sends its video via FTP to its Web host Pageviews at the site exceed 500,000 per month and the station

Figure 1: Real One SuperPass.

Figure 2: OurMaine.com.

e-on demand free to users with an e-online store of over

3000 gift items (Figure 3) The shows available to visitors

range from comedy, horror/science-fiction, popular

inter-est, technology, to health Each show has one or more

episodes and visitors can choose to view any version

de-pending on their own connection speed

WebFN is a financial news network that is a jointventure between Chicago-based Weigel Broadcasting and

New York-based Bridge Information systems Its

webcast-ing works on syndication as the primary source of revenue

(although it currently uses the broadcast model while it

builds its syndication business) At the time of writing,

it streams 12 hours of live video and data each business

day over the Web and also on two Midwest TV stations

Programs are produced for use simultaneously on the

Web and on television The WebFN.com Web site also

of-fers around-the-clock video on-demand service (Figure 4)

Its trademarked “Viewcaster” presents a streaming video

window and below it a window with interactive charts and

graphs that are updated according to the in-stream news

content The webcast is presented in a “program wheel”

format, rotating the featured segments at regular

inter-vals during the hour plus five-program sector

reports—-“Markets in a Minute,” “CEO:FYI,” “Ask an Expert,” “Bull

Session,” and “WebFN University.” WebFN is working onsyndicating their content to other financial Web sites such

as Fidelity They are also developing content partners inEurope and Asia in order to eventually offer a 4-hour live

global webcast (Digital TV, 2001).

TYPES OF WEBCASTING

There are three types of webcasting based on the ogy that webcasters use to deliver the content or informa-tion to the Internet audience: (1) push, (2) on-demand,and (3) live streaming (Miles, 1998) Webcasting can bestreamed live or be downloaded and stored on the serverfor later retrieval by the users Table 1 compares the differ-ences between the three types of webcasting technologiesbased on consumers’ effort and revenue sources

technol-Push Technology

Push technologies are computer programs that deliverthe media content or information to the audience’s com-puter screen automatically without specific request eachtime The information may pop up as an alert, wallpa-per, or screensaver on a person’s computer, as electronicprogram guides on a TV screen, or as other displays onmobile devices or cellular phones How the webcasterknows what content to push to the computer screen ofthe consumers is based on some level of intelligence such

as the customer’s needs or interests, previous information

Figure 4: WebFN.

requests, or an affiliation or portal site registration such

as Yahoo!

One of the earliest companies that successfully employ

the push technology on the Internet for webcasting was

PointCast Founded in 1992 to deliver news and other

information over Internet connections, PointCast’s

flag-ship product PointCast Network sent customized news to

users’ desktops PointCast Network was free to consumers

and supported by advertising To use it, one needed to

download the PointCast client program, which was

avail-able from PointCast’s Web site and other affiliated sites

The user provided preferences for customized

informa-tion, which was delivered by Pointcast as screensavers

The company was acquired by EntryPoint in 1999 and

is now defunct, its push service discontinued shortly

af-ter the acquisition The pioneering push technology and

proprietary software that Pointcast used encounteredmany technical difficulties such as slow service to cus-tomers, causing traffic jams on corporate networks OtherWeb sites such as Yahoo! and Excite offered similar cus-tomized information services only when consumers usedthose sites Consumers preferred this model over Point-cast’s push model, leading to the termination of Point-cast’s service (Bicknell, 2000) The failure of Pointcastdoes not mean that push technology is not a success-ful model of webcasting; it underscores the importance

of bandwidth limitation in the use of pushing ogy Electronic mail software companies successfully andwidely use the push technology to disseminate informa-tion to their users Software companies push product up-dates and downloads to the users such as the latest version

technol-of McAfee antivirus programs, Eudora, Internet Explorer,

Table 1 Comparison of Three Types of Webcasting Technologies

Consumers’ effort None/Automatic High (must locate where the content is Moderate (must know the

available and know what content webcast schedule)

to ask for)Business model Advertising and E-commerce, pay per service, and Advertising, pay per service,

T YPES OF W EBCASTING 679

and Netscape Audio, graphics, and Web pages are sent

automatically to the users’ e-mail boxes

The push and pull technologies work together to vide consumers effortless access to information of inter-

pro-est to them Pull technologies use software to pull

infor-mation for the consumer from the Internet Consumers

can set up their own selections, or the intelligent software

agents can search out information that consumers would

be interested in Amazon.com, for example, has pull

tech-nologies that remembers the products consumers have

purchased in the prior visits and pull information of

sim-ilar products to the user on the next visit

The greatest benefits of using the push technologies

is that consumers can download programs, receive news

updates, and interact with the webcaster in different

for-mats such as audio, video, text, and graphics without

ac-tively searching for the information It brings “intelligence

and efficiency to the distribution of all kinds of

informa-tion, giving webcasters more control over what users see

and when” (Miles, 1998, p 24) Push technologies

pro-vide effortless reception of materials with little consumer

knowledge requirement and save consumers the time to

find information on the Internet

The latest development in push technologies is tobecome more interactive and automatic Webcasters in-

creasingly provide information based on users’ past

behaviors and their response to previous information

Editors are seldom used to sort or filter content Some

inherent problems of push technology surround how

much information should be provided to the audience and

the potential invasion of Internet users’ privacy by pulling

intelligence from users’ past choice and preferences

without their explicit consent Users are increasingly

in-tolerant of unsolicited materials that webcasters send

without permission They will tune out these materials

and the effectiveness of pushing materials is thus greatly

diminished

On-Demand

On-demand webcasting refers to the webcasting of

content based on the request of the consumer at the time

of use The webcaster supplies the media contents in a

catalog or playlist for consumers to choose The term

on-demand refers to the ability of the user to control the

scheduling and appearance of the webcast The audience,

instead of the webcaster, chooses when and what to view

In many on-demand webcasts, additional features are

provided, such as instant replay; no waiting for rewind or

fast forward during live events; interactive devices such as

question and answer, chat rooms, product or service order

forms, multiple camera angles, and zooming in and out

the picture On-demand webcasting’s greatest attractions

are the convenience to the consumer and the audience’s

ability to retrieve information or content that has been

missed There are both business and consumer uses of

on-demand webcasting Business and governments are

already making use of on-demand webcasting to provide

training and product information for employees, suppliers,

and customers Intel, for example, frequently uses

web-casts to provide live seminars to prospective customers

On-demand webcasting can be downloadable or showthe content in real time If the webcast is downloadable,

compressed files are downloaded to the user’s computerand a media player is used to play back the files (alsocalled HTTP streaming) On-demand can also use real-time streaming to broadcast the content directly from aserver as selected by the user so that the user can instantlywatch or listen to it No file storage or cache is involved

in streaming (Real Networks, 2002) Users cannot store,copy, or retransmit the content because the stream nevertouched the local drive of the user and the data are dis-carded after playback Hence the content owners can pre-vent piracy of their content In addition, on-demand canextend webcasters’ reach, increase the value of their mediacontents over a long period of time, and save bandwidth

as well because not everyone connects at the same time(Mack, 2002)

Live Streaming

Streaming is an Internet data transfer technique that doesnot need to wait for the whole file to download to a user’scomputer before playback begins (Mack, 2002) It involves

three different types of software: (1) an encoder, which

converts an audio or video signal from an analog format

to a digital format and compresses the digital files for

transmission over the Internet; (2) a server, which ers data streams to audience members; and (3) a player,

deliv-which viewers use to watch or listen to the streaming dia The content of webcasts using streaming technologiescan either be live or on-demand In live streaming web-casts, the broadcast schedule is fixed so that time-sensitivecontents can be delivered instantaneously to users Usersmust follow the schedule to receive the content Live web-casts require multiple streaming servers to reduce the load

me-of each server and to minimize the chance me-of crashing aserver by too many users tuning in at the same time

In a live streaming webcast, users can also interact withthe event as it is happening such as clicking on a picture of

a car to view its details or change its color Although manyrefer “streaming” to the retransmission or repurposing oftraditional broadcast content such as television and radiosignals on the Web, streaming is not limited to retrans-mission It can also be original content transmission withintent to reach the public Webcasting using streamingtechnology can pick up viewers or listeners from areasaround the world

The ability to squeeze the audio and video into a stream

is the basis of streaming technologies These technologiesuse software to compress the signals for transmission anddecompress the signals for display on the viewer’s screen

in the correct order continuously so that the viewer canview the content almost instantly It is very important thatthe signals are reassembled in the correct order during thedecompression process Any gaps in between will makespeech and video incomprehensible For successful web-casting using streaming technology, the webcaster needs

to secure a powerful high-speed server to deliver the nal, and they need enough bandwidth to enable multipleusers to view the program

sig-Multicasting can be a method to save on bandwidthcosts for webcasters It is the ability to take one signal andsend it to lots of people through a network or over the In-ternet The one signal locates a device (e.g., a router) thatsends the signal to a number of computers or television

In U.S Population 80 millions 40 millions 20 millions

sets Multicasting is much cheaper than unicasting, which

assigns one stream to each viewer or listener When

mul-tiple users log on to the site, the unicasting webcaster will

need to send multiple streams that take up large amounts

of bandwidth One drawback of multicasting is that the

webcaster needs to enable multicast in routers and cannot

use automatic rate changing to accommodate the

differ-ent connection speeds of users (Austerberry, 2002)

Among the three technologies, on-demand and live

streaming are currently the most well-known webcasting

mode and most popularly used in consumer webcasting

of entertainment content According to the latest

Arbi-tron/Edison Internet 8 study (Rose & Rosin, 2002), nearly

80 million Americans aged 12 or above have either listened

or watched a webcast online, with about 7.2 million

hav-ing tuned to one in the past week Surprishav-ingly, webcasthav-ing

use is not limited to young people About 44% of webcast

users are older than 35 years of age Table 2 provides a

profile of webcast audiences in the United States

Three Levels of Webcasting

Webcasting can be differentiated into three levels based

on the degree of sophistication in the webcasting

tech-nologies used during the webcast An example of

low-end webcasting is pushing information by e-mails E-mail

campaigns targeted at customers, suppliers, and business

associates that have actually requested information are

a proper use of the low-end webcasting to market

prod-ucts and build customer relations The e-mails can include

Web page links and audio and video files Those

unso-licited mass mailings via e-mail, usually called spams, do

not discriminate the identity of the recipients and are sent

from sources unknown to the audience These spammers

are under the scrutiny of state antispam laws and subject

to prosecution

The mid-range webcasting is the placing of video or

audio content on a Web site and providing customers and

associates with 24 hour access to current events and

infor-mation about a company’s products or services The

web-casting can be accompanied with features that enhance

the video and audio experience These features range from

search engines or directories that help visitors to find

spe-cific information, to captioned and cued slides or

dia-grams that can be displayed along with the audio or video

High-end webcasting applications may be either push

or streaming, or a combination of the two High-end

webcasting is similar to traditional broadcasting because

of its expected large audience Nonetheless, it differs fromtraditional broadcasting by its video library accessible ondemand, 24 hr a day Businesses use high-end webcast-ing to disseminate information to remote office locations

or to reach prospective customers or investors The tertainment industry is also using high-end webcasting toenhance the viewing experience with the so-called “en-hanced TV” and to generate additional revenue sourcewith file downloading services for a fee and purchase ofvideo content online Webcasters need to lease high-speedtelephone lines, satellite delivery, and other ways of trans-mitting the live webcast signal to the Internet connection.They also need to purchase sufficient bandwidth that willmeet the demand of the large number of people loggingonto the server at the same time

en-TECHNICAL STANDARDS AND PROTOCOLS OF WEBCASTING

The Internet is a collection of computer networks that areinterconnected and communicate with each other based

on a common protocol called TCP/IP (transmission trol protocol/Internet protocol) Protocols define the way

con-in which one hardware or software component con-interactswith another with respect to specific functionality As web-casts are shown to different people with different comput-ers and Web display devices, protocols and standards areneeded to enable communication across networks Proto-cols become standards when every webcaster uses them.Several agencies set the standards for the webcasting in-dustry The governing standards agency for the Internet isthe IETF (Internet Engineering Task Force) Other orga-nizations such as the ITU (International Telecommunica-tion Union), MPEG (Motion Pictures Expert Group), andW3C (World Wide Web Consortium) also create standardsand their standards have become more important for theindustry (Miles, 1998) Figure 5 illustrates the relation-ships among the webcasting protocols that work collabo-ratively to send a transmission to a user

IETF (Internet Engineering Task Force) Standards

The IETF is an international association of network signers, operators, vendors, and researchers concerned

de-T ECHNICAL S TANDARDS AND P ROTOCOLS OF W EBCASTING 681

Webcaster,s Server

RSVP defines minimum quality

RTP enables synchronization and defines encodings

MPEG set standards compressing digital video and audio files

SMIL allows easy mixing of

media objects

Protocols

Multicast-Enabled Router

Local Area Network

Figure 5: Webcasting protocols in multicasting.

with the evolution of the Internet Four webcasting

stan-dards have been adopted by IETF:

IP multicast;

Reservation protocol (RSVP);

Real-time transport protocol (RTP) and real-time control

protocol (RTCP); andReliable multicast protocols

IP Multicast

IETF identified three ways to transmit from a source to

multiple recipients on the Internet:

(1) unicasting—point-to-point transmission;

(2) broadcasting—one-to-all transmission; and

(3) IP multicasting—one copy is sent to a group address

Unlike unicasting, IP multicasting allows small or large

amounts of digital information to be sent to large

audi-ences Only group members that should receive the

web-casts will actually receive the programs and only one copy

of the information is needed to first reach a group address,

then routed to individual recipients to allow efficient

de-livery of digital information

Reservation Protocol (RSVP)

To ensure the quality of the webcast, which includes

in-tegrity, end-to-end predictability, and efficient bandwidth

utilization of data transmission, it is necessary to specify

the minimum quality standard RSVP, the reservation

pro-tocol, is one kind of quality standards that enhances the

current Internet architecture with support requests for a

specific quality of service from the network for particular

data streams or flows This protocol is designed to allocate

network resources appropriately for the requirements of

the data being sent To optimize transmission for

partic-ular types of data such as audio and video, RSVP defines

the network traffic class and is used to control both

qual-ity of service and resource management for unicast andmulticast sessions

Real-Time Transport Protocol (RTP) and Real-Time Control Protocol (RTCP)

Because audio and video webcasts transmitted over theInternet can be lost or experience variable delays, RTP is aprotocol intended to enable synchronization and recoveryfrom loss or delays RTP also defines a format for differ-ent audio and video encodings to promote interoperabilityamong different computer platforms, operating systems,and application software products By having specific datafields that contain timestamp and sequence information,the receiving computer can use these fields to reconstructthe time-specific properties of the RTP data streams A re-lated protocol is RTCP, which checks the status of a web-cast from time to time Using the RTCP, sender and re-ceiver reports are transmitted from time to time so thatapplications using RTP can get RTCP reports on how wellRTP data are being delivered

Reliable Multicast Protocols

Reliable multicast protocols aim to offer 100% data tegrity over a network when needed Sometimes we don’tneed complete data integrity such as when watching amovie because human eyes and ears can tolerate and com-pensate for minor loss or interference in sound and pic-tures However, for transmitting databases or software,

in-no loss can be allowed, and it is necessary to use softwarethat is built in with a reliable multicast protocol

ISO (International Standards Organization) Standards

The International Standards Organization (ISO) is aworldwide organization of national standards organiza-tions from over 100 countries to promote the development

of standardization and related activities in the world Itsgoals are to facilitate the exchange of goods and servicesand to develop international cooperation in intellectual,scientific, technological, and economic activities MPEG

is a group of people who met at ISO to generate dards for digital video and audio compression MPEG-1audio compression standards is composed of three codinglevels: Layer-1 (MP1), Layer-2 (MP2), and Layer-3 (MP3).Each layer level is a higher compression ratio at equalaudio quality To reproduce CD quality audio, Layer-1 re-quires 384 Kbps, while Layer-3 only requires 112 Kbps.MP3 has now become the most popular standard fordigital encoding and transmission of audio and video.MPEG-4 is the latest standard initiated by the ISO Dif-ferent types of multimedia can be combined for differentpresentations using MPEG-4 (Mack, 2002)

stan-ITU (International Telecommunications Union) Standards

ITU (International Telecommunications Union) is an ternational organization where government and the pri-vate sector work together to coordinate global telecom-munications network and services Headquartered inGeneva, Switzerland, the ITU has played an importantrole in standardizing the videoconference industry with

in-standards for electronic program guides (EPG) that will

affect webcasting and the listing of webcast events on

the Internet and television The T120 standard contains

a series of communication and application protocols that

provide support for real-time, multipoint data

communi-cations Over 100 webcast and streaming media suppliers

such as Microsoft and Cisco Systems have already

com-mitted to implementing T120-based products

World Wide Web Consortium (W3C)

Standards

The World Wide Web Consortium (W3C) is an

interna-tional industry consortium founded in 1994 to develop

common protocols for the Web’s evolution The

consor-tium’s current efforts on synchronized multimedia and

extensible markup language (XML) are the most

signifi-cant to the webcasting industry

The synchronized multimedia project is to establish

standards that enable synchronization of different

me-dia (text, graphics, audio, video) so that the presentation

can be shown in a coordinated way As a result of the

project, W3C proposed a new markup language for use on

the Web called synchronized multimedia integration

lan-guage (SMIL) This lanlan-guage was designed to allow the

easy mixing of simple media objects in different formats

The coding would use simple tags to designate elements

on a Web page It will make it easier for people to design

and add webcasting elements to their Web pages The use

of the language will increase the accessibility of the sites

through standardization of media objects display and it

will also increase the accessibility of audio-enabled Web

sites for the visually impaired

XML is an advancement from HTML (hypertext

markup language), which has been the basis for

build-ing Web pages It is a much more flexible language than

HTML and allows designers to define their own

cus-tomized markup language, enabling the use of standard

generalized markup language (SGML) on the Web, which

can define, identify, and use the structure, style, and

con-tent of documents

Proprietary Protocols

Apart from the standards-setting agencies, several

web-casting protocols are proprietary to a software vendor,

but they are eventually submitted to the standards-setting

agencies for consideration to become a common standard

for the entire industry Two such protocols are real-time

streaming protocol (RTSP) and advanced streaming

for-mat (ASF)

Real Networks, Netscape Communications, and

Columbia University developed the real-time streaming

protocol jointly RTSP is an application-level protocol for

control over the delivery of data with real-time properties

The protocol is designed so that delivery of both live data

feeds and stored content can be brought under the control

servers, and clients of multimedia vendors store, stream,and present multimedia content in the same file, instead of

as separate audio, text, graphic, and video files Microsofthas submitted ASF for standards consideration with theISO and IETF

STATE OF THE RADIO WEBCASTING INDUSTRY

Radio is the most common form of webcast tuned in byU.S Internet users mostly during work hours (Measure-cast, 2002) The latest Arbitron/Edison Internet 8 study(Rose & Rosin, 2002) shows that 25% of Americans aged

12 or above have listened to a radio station on the net, although weekly listening was composed of only 4%

Inter-of online radio listeners Only 45% Inter-of the online radio teners listened to local radio stations most often The restmost often listened to stations from other parts of (41%)

lis-or outside the United States (9%)

The audience size of individual radio webcast is stillsmall Among the top 10 radio webcasts, none of themhave a monthly cumulative measured audience (CUME)

of more than 400,000 listeners, according to cast, Inc., the company that provides next-day audi-ence reports for advertisers and Internet broadcasters(http://www.measurecast.com) MusicMatch, which pro-vides an Internet-only radio webcast, charging a subscrip-tion of $3.33 a month, topped with a CUME radio webcastaudience of 365,783 in September 2002 Virgin Radio ofLondon, which has the highest CUME, only had a CUME

Measure-of 264,788 in September 2002 The U.S.-based radio tion that had the highest CUME during that same periodwas WQXR-FM, a New York-based classical music sta-tion Its monthly CUME is only 83,550

sta-According to BRS Media’s study in April 2000, 9,321radio stations had Web sites, of which 5,945 wereU.S./Canadian radio stations The top 10 features of radioWeb sites, according to Arbitron/Edison Media Research,are DJ info/pictures, community events, links to advertis-ers, cool links, station information, contest entry forms,program schedules, concert information, e-mail contact,and station listening link (Gunzerath, 2000)

Levi’s (2000) white paper presented to the NAB dio show reported that 37% of all radio stations of-fer streamed audio, and there are a growing number ofInternet radio stations that only operate exclusively onthe Web for Internet audiences Because most Web radiooriginates from terrestrial broadcast radio stations, theresulting Web radio stations base much of their content

ra-on their terrestrial broadcast radio statira-on counterparts

STATE OF THE TELEVISION WEBCASTING INDUSTRY

Compared to the radio webcasting industry, the TV bcasting industry received much less attention from the

we-P ROBLEMS AND I SSUES IN W EBCASTING 683

press Nitschke (1999) conducted a survey regarding TV

stations’ Internet operations, which found about 70%

maintain their own Internet operations with an in-house

staff Among those 37 stations who answered the survey,

about 30% have streaming media services providing audio

and video files Only 14% have chat rooms and 27% have a

listserv for e-mail broadcast Some TV companies, such as

NBC and the Hearst-Argyle television station group,

sub-contract the webcasting operation to special webcasting

service companies such as the Internet Broadcasting

Sys-tems (IBS) IBS develops and hosts the sites, hires and

manages the Web editorial staff, and builds revenues for

the stations All its sites serve archived and streaming

videos and have a similar design to that of members of

the IBS network Chan-Olmsted and Ha’s (in press)

re-cent survey of TV station managers show that customer

relation management and collection of audience

intelli-gence are the main goals for TV stations to establish their

online presence The revenue stream that most broadcast

stations expect from their webcast is advertising (76%)

Barter (24%) and e-commerce (19%) are a distant second

and third

Transferring their domination on television, the jor national TV networks’ webcasts are the most popular

ma-among TV webcasts CNN, MSNBC, and CBS News are

the forerunners in TV webcasts, according to the DFC

Intelligence Research Study (Miles & Sakai, 2001) With

the high demand of bandwidth for video streaming, it

is not surprising that TV webcasting is used much less

than radio webcasting Arbitron/Edison’s Internet 8 study

(Rose & Rosin, 2002) revealed that only 7% of Internet

users watch a video webcast, which is three and a half

times less than radio webcast numbers The major

obsta-cle of video webcast is the requirement of a high-speed

Internet connection for Internet users to watch a video

webcast

MAJOR PLAYERS IN THE

WEBCASTING INDUSTRY

Seattle-based software companies such as Microsoft and

Real Networks are important players in the webcasting

in-dustry According to the Arbitron/Edison’s Internet 8 study

(Rose & Rosin, 2002), the top four streaming media

ser-vice providers to consumers are Real Network’s Real.com,

Yahoo Radio, MSN Music, and Radio@AOL Microsoft’s

Windows Media Player and Real Network’s RealPlayer are

the most frequently downloaded streaming video players

According to the January 2002 Nielsen/Netratings, Real

Player is used by 32.9 million U.S households while

Win-dows Media Player is used by 14.2 million households

Apple Quicktime, as a latecomer to the webcasting

indus-try, is now a popular multimedia player among people

un-der 21 with 8.1 million home users (Miles & Sakai, 2001;

Olsen, 2002) Real Networks recently launched the

Univer-sal RealOne Player, a multiplatform media player that can

play and cache all media types including Apple Quicktime

and Windows Media

The International Webcasting Association (IWA) isthe largest worldwide nonprofit trade organization rep-

resenting companies, organizations, and individuals

active or interested in the delivery of multimedia (http://www.webcasters.org) The IWA is headquartered in Wash-ington, DC, and serves members throughout the UnitedStates, Europe, Asia, Canada, and Australia

PROBLEMS AND ISSUES

IN WEBCASTING

The webcasting industry is facing several problems Thefirst problem is the cost of the digital content and copy-right issues They have to protect the content from be-ing stolen or reproduced by other webcasters and userswhile securing contents with reasonable fees Secondly,webcasters compete for audiences with offline mediasuch as television and radio Thirdly, webcasting qualityand delivery efficiency depend on the degree of broad-band Internet access penetration of the market Fourthly,webcasting content development needs to take into ac-count the bandwidth requirement and downloading time

to users Lastly, the regulations of the Internet and

on the freedom of speech can greatly affect webcastcontents

Cost of Digital Content and Copyright Issues

The cost of digital content and copyright protection arecurrently the larger issues concerning webcasters espe-cially Web radio, which broadcasts music on the In-ternet The report of the Copyright Arbitration RoyaltyPanel (CARP) recognizes the sound recording and musicalwork performance rights of the sound recording industryand recommends that webcasters pay the high royaltiescharged by the sound recording companies Specifically,webcasters must pay for each performance by the num-ber of listeners After the Library of Congress revised theroyalty rates, webcasting companies with or without anoffline radio station will pay the same rate of $0.07 perperson This rate is nearly 10 times higher than the ratesuggested by webcasters and approximately 35% of theroyalty fee requested by the Recording Industry Associa-tion of America (RIAA) Both the National Association ofBroadcasters and the International Webcasting Associa-tion protested against the CARP recommendations (IWA).Many Web radio stations have shut down to protest thedecision and avoid being fined In a survey of readers

of Streaming Magazine, who mostly are webcasters and

streaming technology suppliers, 80% think that the suggested royalty rates will kill the Internet radio business(Jeffrey, 2002)

CARP-The Small Webcaster Settlement Act (HR5469) wasintroduced and passed in the U.S Congress recently inNovember 2002 to help small webcasters The bill offers alower royalty rate to small commercial webcasters by onlycharging 8% of the gross revenue or 5% of the webcasters’expenses for the royalty fee for the retroactive periodbefore December 2002 Now webcasters with less thanUS$50,000 in gross revenue will pay a minimum annualfee of $2,000 Other webcasters will pay a 10% royalty feeout of the gross revenue for the first $250,000 and 12%

of the gross revenue when the revenue exceeds $250,000;

or 7% of the operating expenses, whichever is greater.However, the bill does not apply to college webcasters so

as the original and to retrieve and store digital content

on the Web, webcasters must protect their own copyright

for original content The U.S Congress enacted the

Digi-tal Performance Right in Sound Recordings Act of 1995

This act only applies to digital audio retransmission and

requires webcasters to obtain a performance license from

the owners of the sound recording rights In addition,

the Digital Millennium Copyright Act (DMCA), written

in 1998 under the treaties by the United Nation’s agency

World Intellectual Property Organization, provides for a

simplified but statutory licensing system for digital

per-formance of sound recordings on the Internet and via

satellite Its provisions include a programming restriction

called the “Sound Recording Performance Complement”

(SRPC) The restriction includes no more than three songs

from a particular album, no more than four songs by a

par-ticular artist, and no more than three consecutively in a

three-hour period and no advance song or artist playlist

announcement may be published The current

contro-versy over the Copyright Arbitration Royalty Panel’s

re-port and recommendation is a result of that Act

Competition for Audience

with Offline Media

Although some have argued that webcasting serves a

to-tally different type of audience from other traditional or

offline media such as television and radio with its

inter-active capabilities and niche programming, it is still a

medium that competes with offline media for both

adver-tising dollars and audiences The growth of webcasting

will result in more audience fragmentation, as thousands

of webcasts are available on the Internet Nevertheless,

webcasting also brings in new audiences—audiences at

work and audiences not served by niche programming or

limited by local programming in the past In order to win

the competition for audiences, both webcast media and

other offline media must work even harder to understand

and discover an audience’s unmet needs and provide the

service that meets those needs

On-demand webcasters may have a tough time in

com-peting with digital cable TV’s videos-on-demand service,

which offers consumers the choice to watch programs on

TV in digital quality whenever they want The interactive

services provided on digital cable can be comparable to

the interactive devices in a webcast In addition, the

in-creasing penetration of personal video recorders (PVRs)

that allow live recording and skipping of commercials on

television is another potential competitor to on-demand

webcasting to consumers Consumers can shift their TV

viewing schedule and select the content they want easily

with PVRs, making webcasting a less appealing viewing

option The advent of satellite radio may reduce the

attrac-tiveness of Web radio because satellite radio can provide

radio service with digital sound quality on the road on a

national basis without commercial interruptions The

ma-jor selling point of webcasting is its transcendence of

ge-for the growth in the use of webcasting because theconnection speed of dial-up modems is too slow to pro-vide acceptable audio and video quality for entertainmentuse Currently, about 30% of Internet users in the UnitedStates are broadband users (i.e., 33.6 million) according

to Nielsen/Netratings (January 2003) To users withoutbroadband access, viewing video is not only inefficient but

a frustrating experience because the gaps between ing data transmission created garbled and incomprehen-sible images and audio sounds The increase in broadbanduse results in an increase in webcasting usage Nielsenestimated that about 12.7 million broadband Internetsurfers consumed streaming media content at home Thebandwidth requirement for a large number of audiences

stream-in webcaststream-ing is also a big hurdle for many webcasterswhen the public Internet system is used For example,when Madonna’s live concert in London was webcasted

in November 2000, nine million streams were served tothe Internet audience MSN produced the show to gen-erate publicity However, the webcast cost MSN so muchthat MSN could not afford to pay Madonna the concertrights

Development of Webcasting Content

The development of webcasting content must take intoconsideration the bandwidth requirement and transmis-sion quality Videos, for example, take up a large amount

of bandwidth, and should therefore be used very tively Short video clips and interactive features are muchmore effective than full-length video in webcasting Ani-mation and showing images in a sequence ensure the re-ception quality to the user because the loading time forimages and visuals is much less than a video They can be

selec-as effective selec-as a video in many instances

Navigation design is another important issue in oping webcasting content Webcasters need to organizethe content offering into separate categories and displaythe approximate playing time by the modem speed of theuser A user-friendly menu will enable the user to quicklylocate the webcast content to be played and control thepace of the webcast If the contents have been used inother offline media, a reference to the original aired dateswill be of high reference value to the users Digital copy-right management is another important aspect in webcastcontent development

devel-Regulatory Issues in Webcasting

Apart from copyright protection, there are several latory issues pertinent to webcasting: (1) extension of theright of publicity online (state laws prohibiting the unau-thorized taking of an individual’s name, likeness, voice

regu-or other elements and using them fregu-or commercial poses); (2) invasion of privacy by the Internet’s ability tocollect data and customize information; (3) libels in bul-letin boards and chat rooms; and (4) freedom of speech

pur-G LOSSARY 685

on the Internet and censorship issues The

Communica-tion Decency Act of 1996 was ruled unconstituCommunica-tional by

the Supreme Court, which established that the Internet

enjoys the same First Amendment rights as other print

media formats Essentially, the access and cost to use

In-ternet services determine how many will be able to use

webcast

WEBCASTING AROUND THE GLOBE

The United States is taking the lead in the webcasting

market development by promoting private investment for

universal Internet access Europe is lagging behind in

we-bcasting market development because of the charge per

use rate structure of local phone service and the high price

of leased lines and dedicated circuits Asia is also

gener-ally underdeveloped in consumer webcasting because of

limited press freedom in most Asian countries

Neverthe-less, the high broadband adoption rate in the Four Little

Dragons in Asia (Hong Kong, Singapore, South Korea,

and Taiwan) and the vibrant business environment

fos-ter a fertile ground for business-to-business webcasting

B2BCast is a webcasting company based in Asia

provid-ing business-to-business webcastprovid-ing It focuses on

pro-viding business executives on-demand access to business

events and conferences 24 hr a day, such as the Asian

Cor-porate Branding Symposium The Hong Kong Trade

De-velopment Council’s web site features business webcasts

with eight different channels (http://www.tdctrade.com).

Consumer webcasting is blossoming in Taiwan with the

encouragement of the government on broadband

devel-opment For instance, HiNet, a Taiwan broadband

In-ternet service provider (http://www.hichannel.hinet.net),

provides its subscribers live webcasts of swimsuit model

shows every evening and celebrity interviews Latin

Amer-ica’s webcasting industry is hampered by its low Internet

usage rate Brazil, Argentina, Chile, and Mexico are the

most highly developed Internet markets in Latin America

However, less than 5% of their population uses the

Inter-net (Cyberatlas, 2002)

CONCLUSION

Webcasting is still an infant industry with many small

entrepreneurs and large enterprises experimenting their

way A liberal regulatory climate and broadband Internet

access adoption are key environmental factors to foster

the growth of this industry Either willingly or

unwill-ingly, traditional broadcast media such as radio and

tele-vision have participated in the brave new world of

we-bcasting Does webcasting pose a threat to traditional

broadcast media or will its presence further strengthen

the value of the traditional media? Media history

repeat-edly shows that each medium will modify itself to adapt

to the changes in the environment, find its own niche, and

survive the threat of new media, unless the new media can

completely substitute for the functions of the traditional

medium such as the replacement of vinyl records by

com-pact discs and cassettes Just as television was unable to

displace radio, and radio was unable to displace

newspa-pers, the Web will not displace television or radio Instead,

audiences are given more choices with webcasting

De-livering of multimedia content is much easier now thanbefore with the different webcasting technologies and ad-vancement in webcasting protocols By integrating the lat-est technology on the Web and the traditional media con-tent, broadcasters may find higher value in their mediacontent and a much larger audience in the workplace andhome and around the world The interactive capability ofthe Web opens the door for a variety of revenue streamsfor the most creative broadcasters/webcasters who bestserve the needs of consumers and know how to maximizethe value of their content

GLOSSARYCUME (cumulative measured audience) The num-ber of different or unduplicated homes/people exposed

to a program at least once across a stated period oftime

Extranet An external Web site created by an tion to provide information and support services withrestricted access, such as passwords or security codes,

organiza-to its cusorganiza-tomers, clients, suppliers, or members

FTP (file transfer protocol) The Internet application

of moving files across the Internet using the TCP/IPprotocol by either uploading a file to a computer server

or downloading a file to a user’s local computer drive

Intranet An internal Web site created by an tion to provide information and communication for itsemployees, its purpose being primarily for business us-age but also to be used as an internal corporate com-munication tool

organiza-NAB (National Association of Broadcasters) A cast industry association representing the interests offree, over-the-air radio and television broadcasters

broad-Pull The process of using software to find information

on the Web for the consumer to view through a browser

or e-mail; can be initiated by the consumer or ically processed by the Web site server

automat-Push The delivery of information by a company to auser’s computer on a regular basis, ranging from sim-ply sending regular e-mails to providing customizedinformation in multimedia format based on either theuser’s request or automatic intelligence agents that de-termine the user’s tastes and preferences

Real time The delivery of media content, data, audio, orvideo at almost the same moment it originates on theWeb; equivalent to a “live” broadcast on the computerscreen

Repurpose The media content management strategy ofusing the same text, audio, or graphics content again

in other media channels by the copyright owner of thecontent, the term originating from content created forone purpose (a TV newscast) being used for another(a webcast), which can be longer or shorter than theoriginal content or exactly identical Also the mediacontent is still considered the same and under the pro-tection of copyright law even though the distributionmedia have changed

RTP (real-time transport protocol) An Internet col that provides a timestamp and sequence number tofacilitate the data transport timing and to control themedia server so that the video stream is served at the

proto-Currently, service providers such as XM and Sirius

provide satellite radio services in the United States on

a subscription basis

Streaming The technology of sending a continuous

data signal through the Internet with special software;

enables the user’s computer to decode a signal as soon

as it is received and play it almost immediately in

the correct order Unlike downloading, which requires

the storage of the data in the user’s local hard drive

be-fore playback, streaming data are not cached (stored)

in the user’s local computer drive and play back the

data at almost the same time as they are transmitted

CROSS REFERENCES

See Copyright Law; Extranets; Intranets; Video Streaming.

REFERENCES

Austerberry, D (2002) The technology of video and audio

streaming Woburn, MA: Focal Press.

Bicknell, C (2000, May 29) Pointcast coffin about to shut

Wired Retrieved October 31, 2002, from http://www.

wired.com/news/business/0,1367,35208,00.html

Chan-Olmsted, S., & Ha, L (in press) Internet business

models of broadcasters Journal of Broadcasting and

Electronic Media.

Cyberatlas (2002) The world’s online population

Re-trieved November 20, 2002, from http://cyberatlas

internet.com/big picture/geographics/article/0,1323,

5911 151151,00.html

Digital TV (2001, February) Webcasting 45–50.

Gunzerath, D (2000) Radio and the Internet

Retri-eved May 13, 2002, from http://www.nab.org/Research/

topic.asp#INTERNET

Ha, L., & Chan-Olmsted, S (2001) Enhanced TV as brand

extension: TV viewers’ perception of enhanced TV

fea-tures and TV commerce on broadcast networks’ Web

Mack, S (2002) Streaming media bible New York: Wiley.

Measurecast, Inc (2002) Measurecast reports tian music format popular with Internet radio lis-teners Retrieved August 28, 2002, from http://www.measurecast.com/news/pr/2002/pr20020827.html

Chris-Miles, P (1998) Internet World guide to webcasting: The

complete guide to broadcasting on the Web New York:

Wiley

Miles, P., & Sakai, D (2001) Internet age broadcaster (2nd

ed.) Washington, DC: National Association of casters

Broad-Nielsen NetRatings (2003, January) Broadband accessgrows 59 percent, while narrowband use declines, ac-cording to Nielsen/Netratings Retrieved April 14, 2003,from http://netratings.com/pr/pr 030115.pdf

Nitschke, A (1999) Station Internet activities report.Retrieved May 10, 2002, from http://www.nab.org/Research/Reports/TvstationInternetActivity.aspOlsen, S (2002, June 19) Apple: We told you QuickTime

was #1! CNET News.com Retrieved April 14, 2003,

from http://zdnet.com.com/2100-1105-937379.html.Real Networks (2002) Streaming media F.A.Q Re-trieved August 5, 2002, from http://www.realnetworks.com/resources/startingout/get started faq.htmlRose, B., & Robin, L (2002) Internet 8: Advertising

vs subscription—Which streaming model will win?Arbitron Inc and Edison Media Research RetrievedAugust 7, 2002, from http://www.arbitron.com/home/content.stm

Schlender, B (2002, March 4) The real deal Fortune,

215–220

Vonder Haar, S V (2002, July) Streaming media gets

se-rious Baseline, 83.

Web Content Management

Jian Qin, Syracuse University

Version Control and Collaborative Authoring 689

Content Representation and Organization 690

Web content management is a process in which

con-tent management solutions are used to create, store,

pub-lish, update, and repurpose content to be communicated

through an organization’s Web site The content may

ap-pear in the form of HTML, XML, image, audio/video,

plain text, or database The management of these assets

is achieved through using templates, workflow tracking

features, publishing systems, and storage of content

ob-jects in database or file indexing systems Web content

is rapidly becoming one of the primary components of

the competitive advantage for all types of organizations

Whether an organization’s Web site can attract and retain

users plays an important role in an organization’s

suc-cess, especially for e-businesses The increasing

impor-tance of Web content demands better and more

respon-sive methods and technologies that produce and provide

access to it

Web pages of the early days were created mainlythrough manual HTML coding and the content contained

in these pages was static As the number and types of files

composing a Web site grew rapidly, manual coding and

linking became time-consuming and error-prone The

sit-uation could worsen when more than one person worked

on the same Web project The need for effective and

dy-namic publication of data and link creation on the Web

prompted a new generation of the Web The early dynamic

generations of Web content primarily used programming

interfaces and languages such as the common gateway

interface (CGI) and Perl Later, other programming

lan-guages, e.g VBScript, JavaScript, and JavaServer Pages

(JSP), became popular By using computer programs and

stylesheets, data stored in databases could be browsed or

retrieved and displayed on the fly in a predefined style

Although dynamic presentation of data on the Web was

accomplished by utilizing information technology, new

challenges emerged One such challenge was version

con-trol In the case of a large team working on a Web site

that contains hundreds or thousands of files, poor

coor-dination and lack of version control can cause

unneces-sary damages to the work being done Another problem is

the workflow management As maintaining a Web site comes part of the daily life of an organization, tasks such

be-as creating, editing, testing, approving, and publishingwill involve many people at different levels and in differentspecialization areas A lack of rules and procedures cancreate bottlenecks or blockages of the workflow These twoexample problems demonstrate that creating and main-taining a Web site, particularly a large one, is no longer

a simple matter of assembling a group of HTML pagesand programs More sophisticated systems are requiredfor the production and delivery of Web content Thesesystems are expected to solve problems such as contentcreation, representation and organization, asset manage-ment, access management, production content delivery,version control, and scheduling

Web content management becomes the term referring

to a system that performs all these tasks, as well as thepractice that uses the system to produce, deliver, and man-age Web content It is therefore used to mean both pro-cesses and the technology involved This chapter will dis-cuss Web content management primarily following theprocesses from content creation to delivery Key technolo-gies will be mentioned when necessary, but vendors forparticular products will not since they are not the focus

of this chapter

WEB CONTENT LIFE CYCLE

Components in a Web content life cycle are given ferent names depending on how developers view andbuild the content management system Latham (2002)proposes a six-phase life cycle for more general contentmanagement They are creation/acquisition, review, ag-gregation/management, distribution, archiving, and de-struction, all in the context of workflow and integration.IBM defines a Web content life cycle as having four majorelements: content creation, content management, con-tent access management, and production content deliv-ery (IBM, 2002a) Content-wire.com (http://www.content-wire.com) includes 11 columns in a content life cycle:accessibility and usability, audiovisual, billing, content

dif-687

Content deployment

Browse Search Create new content

Export Publish Transformation

Web WAP Email Catalog Portals

Figure 1: Web content life cycle.

delivery, content management, creation, digital copyright,

syndication, taxonomies, unwired, and vertical content

No matter how content management systems and

prac-tices vary, Web content must go through the processes of

creation, management, and deployment (Figure 1)

Con-tent creation includes new conCon-tent creation and existing

content conversion such as data from databases and/or

legacy content Content management embraces many

as-pects such as

(1) asset management, i.e., managing all pictures and files

to avoid data redundancies and easily handle media

files;

(2) access management, which integrates user

manage-ment and the permission systems;

(3) template management, which involves using dynamic

page rendering mechanisms to allow a uniform

pre-sentation of content; and

(4) content representation and organization, which

gen-erates metadata and structured content

Content deployment is the transfer of Web assets from

the staging server to the production server Current

tech-nology allows content on the production server to be

broadcast not only to an organization’s Web site, but

also on other application devices Because Web content

is structured and organized in a way that can be reused,

the system can render the same content into a variety of

formats such as Web pages, wireless hand-held devices,

e-mails, and catalogs, besides desktop browsers Such

content should also provide easier but more powerful

browse and search capabilities for the front-end users

CONTENT CREATION

AND AUTHORING

Web content results from business processes such as

plan-ning, design, and implementation and falls into a

num-ber of large categories—depending on which criterion is

used to categorize the content For example, commonly

seen content types include information on products,

pro-cedures and guidelines, reports from research or

devel-opment projects or business transactions, presentations,

and white papers to the public While these content types

serve different purposes in business processes, their

cre-ators may work at various positions (e.g., managers,

pro-creation and authoring includes design, version control,collaborative authoring, and document management.These components work together to provide an infrastruc-ture on which Web site functions and services are built

Content Design

The general principles for content creation are to keepdocuments small, to build a modular system, to reuse con-tent and definitions as much as possible, and to createpowerful metadata (Gabriel, 2001) The size of display ar-eas is limited on computer screens and smaller devices.Keeping documents small increases the displaying flexi-bility, but more importantly, smaller documents and doc-ument components increase the chance for them to berestructured and reused It also makes it easier to framethe smaller documents into new technologies such as theextensible markup language (XML) (W3C, 2000) The sec-ond principle of modularization has been used success-fully in building business and information systems Forlarge Web sites, modularizing means dividing Web con-tent into modular systems based on certain criteria, e.g.,

by functional unit A large site may have modules for search and development, customer service, and sales andmarketing Although different types of documents andcontent often bear different elements and structure, it isalso quite common that some of them share the same def-initions An example would be news releases—each func-tional unit’s Web site has a news section Therefore, thedocument definition for news articles can be defined onceand reused in all units’ Web sites Content and documentdefinition reuse can save not only time and effort butalso keep similar content in a consistent format Meta-data is information about data and documents Title, au-thor, key words, abstract, and content category are themost common elements for document type of content Fordatabase content, metadata includes, among other things,table name, field name, and data type Metadata containselements underpinning the functions of browsing, search-ing, and displaying

re-When designing Web content, one needs to considerboth its internal and external structures The internalstructure refers to the organization and arrangement ofcontent components For example, an online technicalmanual may be structured as chapters, sections, and para-graphs; within each of the paragraphs there may be still

or interactive illustrations with text annotation An tant design feature for such an online manual would bethat no matter where users are inside the manual, therewould be navigational indictors for them to move backand forth or up and down, even jump from one place

impor-to another Another example is the navigation systemwithin a Web site, which enables “relational” browsingand searching; i.e., similar products, technical support,and promotional plans pertaining to a particular productare related to that product’s description The role of in-ternal structure design is to define Web content types and

C ONTENT C REATION AND A UTHORING 689

structures and map out relationships among components

of Web content

The external structure of Web content refers to the waythat Web content is presented to the front-end users It

defines which data components make up a Web page and

how they will be arranged on the screen: dynamic posting,

JavaScript-enabled interaction, or a drop-down menu

Ex-ternal structure design should also be compliant with the

accessibility guidelines proposed by the World Wide Web

Consortium (W3C) Nonetheless, these guidelines can also

be applied to general external structure design W3C

rec-ommends to

rSeparate (internal) structure from presentation;

rProvide text so that text can be rendered in ways that are

available to almost all browsing devices and accessible

to almost all users;

rCreate documents that work even if the user cannot see

and/or hear; and

rCreate documents that do not rely on one type of

hard-ware (W3C, 1999a)

High-quality content requires planning and decisions

on the sources, formats, and versions of content before it

is created Generally, Web content can be divided into four

broad categories based on its source: internally created

and owned, owned outright (e.g., commissioned artwork),

acquired externally through leasing or subscription, or

linked to external sources but not owned nor leased The

internally created and owned content includes a wide

variety of documents as results of planning, analysis,

designing, briefing, and many other organizational

activ-ities These documents may be in the form of memos,

re-ports, press releases, product catalogs, online transaction

logs, white papers, or technical specifications and created

as HTML or files in other formats (e.g., sound and

im-ages captured in audio/videos, or recorded as data sets)

Some of them are currently active, i.e., being written or

revised, while others may be inactive and eventually

re-moved from the system Some content such as planning

and technical documents often involve collaborative

cre-ation and reviewing; hence the content may be privileged

and need version and access control to ensure the

effi-ciency, consistency, and confidentiality of the content

un-der development Both types of content—internally

cre-ated and owned outright—are assets of an organization,

though the organization does not have the right to revise

or change the commissioned content Content acquired

externally usually comes in a package such as a database

with its own user interfaces, whereas linked content can

be anything and beyond the control of the Web content

management system

Version Control and Collaborative Authoring

The term “version control” has long existed before the

Web It was originally used to manage versions of source

code in programming projects (Fogel, 2001) Version

con-trol software allows a developer or a group of developers

to keep track of versions of program files that

modifica-tions have been made to If a bug emerged after the new

version was implemented, the developer can reinstate theearlier version into the system If several developers areworking on the same source code, the system can detectthe changes and differences and automatically merge dif-ferent versions into one copy Version control in Web con-tent creation and authoring essentially works the sameway as a version control system It records the history in-formation about a file or directory, including things such

as creation date, who created it, and the version number orlabel The version control system allows authorized users

to check out or check in files or directories While a file

or directory is checked out of the system, the user canlock it to prevent other users from accessing the same file

or directory After the updates are done, the user unlocksthe file or directory by checking it back into the system

If a piece of content needs to be removed or added forany reason—or simply an earlier version of the Web site

is preferred—the version control system can be used torestore the entire site to any previous state, rolling backmultiple variations and edits by all authors until a satis-factory site can be put back in place (Dreilinger, 1999).The concurrent versions system was implemented in

a UNIX environment and intended for computer sionals In the Web development environment, versioncontrol is as important as it is in software development.However, Web authors often are not computer profession-als and come with various levels of computer skill Be-sides, the content that Web authors create does not al-ways fall into the category of program source code Theversion control system must be compatible with variousplatforms and authoring tools If a large team of Web de-velopers works on the same Web project, “[t]he assets thatcompose a Web site must be factored in a way that allowsmany members of the Web team to make changes concur-rently” (Nakano, 2002) The nature of Web content cre-ation and authoring calls for user-friendlier version con-trol and authoring tools

profes-Collaborative authoring is so tightly intertwined withconcurrent version control that it is difficult to discussone without mentioning the other The concept of collab-orative authoring encompasses a larger domain than ver-sion control In addition to varied skill levels, Web contentauthors in a distributed environment often use differentauthoring tools on various platforms When they work onthe same project and need to share the same documents,the version control system needs to be interoperable be-sides accommodating different skill levels To support col-laborative authoring, the system needs to meet the re-quirements of equal support for all content types, concur-rency control support, support for metadata, support forcontent-type independent links, retrieval of unprocessedsource for editing, namespace manipulation, and supportfor collections (Whitehead, & Goland, 1999) In address-ing these challenges, the Web Distributed Authoring andVersioning (WebDAV) working group of the Internet En-gineering Task Force (IETF) developed the WebDAV pro-tocol in support of the remote collaborative authoring

on the Web (Goland, Whitehead, Faizi, Carter, & Jensen,1999) Figure 2 demonstrates how authors in different lo-cations using different authoring tools can edit the sameset of documents with WebDAV server’s version controlfunctions

WebDAV protocol

WebDAV protocol

WebDAV server

PhotoShop 7

Concurrent versions control

Project Web site /project

(shared documents)

/html /images WebDAV protocol

Figure 2: Collaborative authoring in three different locations

and each Web author uses a different set of authoring tools

Content authoring with concurrency control can make

content creation efficient and ensure its consistency and

quality Authoring tools allow content creators to set

tem-plates and create consistent content structures for easy

deployment There is a wide variety of authoring tools

available on the market, ranging from HTML to XML

editors, many of which have capabilities of facilitating

collaborative authoring

Document Management Systems

Managing documents—e-mail messages, spreadsheets,

image files, media files, or textual material—traditionally

uses file systems in which documents are organized by

location in hierarchies The hierarchical structure of

fold-ers maps out the semantic structure of the file system

However, the hierarchical file system is not without a

problem For instance, documents can appear only in one

place in the structure, even though they may play different

roles and be relevant to other activities As Dourish et al

(2000) described, the ideal document management system

is the kind that provides a logical structure for document

storage (meeting the needs of the system) while

support-ing document interaction (meetsupport-ing the needs of users)

Many commercial document management systems are

built based on document properties, rather than

docu-ment locations, because docudocu-ment properties are “the

primary, uniform means for organizing, grouping,

man-aging, controlling, and retrieving documents” (Dourish

et al., 2000, p 142)

A document management system may be a collection

of roughly related systems that perform one or more of

several functions, or a system consisting of a number

of functional modules Typical document management

systems perform the following functions, though no one

system performs them all:

rFile naming: allowing long, descriptive file names;

rIndexing: assigning or extracting keywords and

compil-ing them into lists;

rMultifile document control: presenting an electronic

document consisting of multiple files in various formats

to users as if it were a single entity;

ural or human disasters;

rWorkflow management: coordinating tasks, data, and

content creators and developers to make the processmore efficient and effective; and

rPresentation/distribution services: deciding the form

and manner in which users view and interact with thecontent (Cleveland, 1997)

Increasingly, content developers use conceptual ing methods to design the structure and relationships for

model-a dommodel-ain, in which dmodel-atmodel-a, documents, model-and model-applicmodel-ations model-areplanned together in a systematic manner These concep-tual models sometimes are called “ontologies.” Content-encoding schemas and application programs are then de-veloped based on the conceptual models Such schemasapply XML syntax and in some cases, the resource de-scription framework (RDF) syntax (W3C, 1999b), whichpermits some inference or reasoning to allow intelligentagent applications

CONTENT REPRESENTATION AND ORGANIZATION

Many Web sites today use representation and tion schemes of some sort Yahoo! has its own categorylist that lets users browse its collection of Web sites hi-erarchically Amazon.com uses a patented algorithm torecommend books or other goods based on the query auser entered for searching Without a proper represen-tation and organization of data and documents, it wouldhave been impossible to provide these functions Thus, thepurpose of managing Web content is not simply to createsome data and documents and make them available on the

organiza-Web; more importantly, it is to create organized content

so users can interact with it more effectively tion and organization needs to begin with content designand creation and follow through to the presentation (in-terface) on the Web As Web content becomes increasinglycomplex and large in scope, several research communitiessuch as library and information science and computer sci-ence have been actively studying how to represent andorganize content to make it “machine-understandable”(W3C, 1999b) “Semantic Web” is a term describing theactivities in this area, which includes a series of stan-

Representa-dards under development such as Resource Description

Framework (RDF) Schema Language (W3C, 1999b) and Requirements for a Web Ontology Language (W3C, 2002a).

Semantic Web is the abstract representation of data onthe World Wide Web, based on the RDF standards andother standards to be defined According to Berners-Lee

et al (2001), Semantic Web is “an extension of the currentweb in which information is given well-defined meaning,better enabling computers and people to work in coop-eration.” It is being developed by the W3C, in collabora-tion with a large number of researchers and industrialpartners

C ONTENT R EPRESENTATION AND O RGANIZATION 691

Content representation and organization refers to theprocess in which data and document models are created

and relationships are mapped out as the architecture for

templates and interfaces Subsequently, such models are

converted into logic designs and implemented into the

sys-tem Creation of representation and organization schemes

and vocabularies requires methodologies from computer

science, linguistics, library and information science, and

other allied disciplines There are two kinds of tools in

content representation and organization: (1) metadata

schemes that contain data elements describing various

types of data sets and documents and (2) controlled

vo-cabularies that are used to assign subject categories and

indexing terms to documents

Metadata Schemes

A metadata scheme defines a set of properties about data

or documents In the digital library community, there

have been several proposals: the Dublin Core metadata

sets (Weibel, Kunze, Logoze, & Wolf, 1998), the

War-wick Framework (Lagoze, 1996), and the IEEE LOM/IMS

metadata set for learning objects (IEEE/LTSC, 2002; IMS,

2002) The main purpose of metadata schemes is to

pro-vide a consistent way to record data about data sets

or documents and to encode such data in a

computer-understandable manner The most common metadata

elements include authors, titles, dates of creation/

publication, owner/publisher, description, and category/

subject terms Some metadata schemes provide

coarse-grained metadata elements to allow quick generation or

creation of a metadata repository Dublin Core is an

exam-ple of this kind With a structure containing three

pack-ages of content, intellectual property, and instantiation,

it includes 15 elements and their subelements (Table 1)

This set enumerates the very general yet essential data

el-ements necessary for identifying and locating documents

Metadata schemes may also include finer-grained dataelements to describe documents in greater detail For ex-

ample, Dublin Core’s educational extension, DC-ED,

em-ploys a set of elements designed specifically for describing

the grade level, audience, pedagogy, and other details for

a learning resource on the Web In this sense, metadata

schemes are the data models for collecting information

about documents on the Web Such information is used

to search, browse, and locate documents on a topic over

the Web Another use of metadata schemes is to design

them as templates to capture content directly from the

Table 1 Elements in Dublin Core Content Intellectual property Instantiation

Description Contributor Format

LanguageRelationCoverage

Web An example is Web-based forms, which have beenwidely used to capture customer data, survey data, salesorders, and best practices, to name a few

Sometimes no standard metadata scheme is suitablefor representing the types of data and documents beingcreated In such circumstances, a customized metadatascheme(s) is needed The customized scheme may be cre-ated based on a standard such as Dublin Core, with a set

of extended elements It may also be created from scratchwithout using any existing standard However, for inter-operability, a metadata standard should be adopted when-ever possible Since metadata schemes are the data mod-els for collecting information about data and documents,they often need to be embedded in content authoring tools

so that content authors can create metadata while theyare creating documents In either case, i.e., creating an ex-tended metadata scheme or a scheme for capturing data in

a distributed environment, careful design is necessary toguarantee a sound representation of the data to allow easyretrieval and browsing of the content Designing metadataschemes usually involves a data modeling process.Modeling is a process of synthetic analysis and abstrac-tion, in which system developers “construct an abstractdescription of a system in order to explain or predict cer-tain system properties or phenomena” (Schreiber, Akker-mans, Anjewierden, Hoog, Shadbolt, & Wielinga, 2000, p.128) The result of this process is a model in which classes

of objects in the real world are specified as having a parent and one-to-one correspondence to an object in themodel Figure 3 is an example of the data model for an ex-perience factory in the domain of workforce development.The model in Figure 3 provides a high-level view ofmain classes and the relations among the classes In thedomain of workforce development, participating classesinclude the government who sponsors workforce pro-grams such as “Welfare-to-work” and “Study-to-career,”workforce organizations that initiate projects to executeprograms, people in organizations who prepare docu-ments describing and disseminating project informationand results, and knowledge captured for sharing promis-ing practices and lessons learned A data model such asthis serves as a communication tool for users of the Webcontent It shows what kinds of content there will be onthe Web site and how each class is related to one another.Before a data model reaches its acceptable version, discus-sions are often held with constituents to solicit feedback

trans-As with any system development process, this discussion–revision process is iterative

Cases that worked

Lessons learned

Workforce programs Projects

Document

refers-to describes

example-of

is-related-to includes

Figure 3: A sample conceptual model for the workforce

ser-vices domain