E learning tools and technologies phần 2 ppt

E-learning Tools and Technologies X Hardware for e-learning X 45 4 Hardware for e-learning these items, but without adequate video memory, a learner may not be able to have high resolution, high color depth, and a high refresh rate at the same time. Acceleration Graphics cards boost the speed of display operations. This acceleration benefits complex video display operations such as rendering 3-D models or computing visibility of overlapping, translucent objects. (Yes, we mean games.) Most e-learning gets by just fine without acceleration. If you use a lot of complex animation, virtual- reality worlds, or other simulation programs, however, acceleration improves the smoothness of the visual display. Multimedia authors who create and edit multilayered graphics or three-dimensional models will greatly benefit from an accelerated video card because they will have to wait less time while their monitor display redraws. (For some applications, this can be quite time- consuming.) Multiple monitor support From its third model on, Macintosh computers allowed users to connect multiple monitors. Windows has recently added this capability. Now, users who need more screen space can just attach more monitors—provided they add extra display cards or their display card supports multiple monitors. Though not necessary for e-learners, multiple monitors can be a boon for developers who use one monitor to edit their creations and another to view them the way learners will. Recommendations For e-learners, you need to take three factors into consideration: resolution, color depth, and refresh rate. To view e-learning and conduct other day-to-day activities, a resolution of 1,024 x 768 is a safe choice. Specify a color-depth of at least 16 bits. This ensures that color graphics appear as intended, with little or no color banding. Finally, make sure that the video card can display the specified resolution and color depth and still achieve a refresh rate of 75 Hz for a CRT monitor or 60 Hz for a LCD monitor. To achieve all these requirements at once requires adequate video memory. Authors of e-learning require a minimum resolution of 1,280 x 1,024. Many of the authoring tools used today display many windows simultaneously—all of which the author may need to see to be productive. Specify a color depth of at least 16 bits to ensure adequate color fidelity. If the producer will be editing photographs, then specify a color depth of at least 24 bits. Specify a refresh rate of 75 Hz for a CRT Giving authors faster displays will just desensitize them to how their creations appear to learners. Wiley Publishing, Inc. 46 W Hardware for e-learning W E-learning Tools and Technologies monitor. And, you will need graphics acceleration if authors will be editing large, multilayered graphics, animations with transparencies, or three-dimensional models. A 4X rate of acceleration should be adequate. Video monitor A well-chosen monitor can make e-learning pleasant. A poorly chosen monitor can make it painful and frustrating. The video monitor displays what the video card sends it. The characteristics of the monitor parallel those for the video card. You obviously need a monitor that is matched to the capabilities of the video card and vice- versa; otherwise you are wasting money on capabilities nobody will ever see. Physical size The size of the monitor determines the area of the display in inches or centimeters. Size is usually measured from corner to corner diagonally across the display area. For office work, a 17-inch (approx. 43 cm) monitor is typical. For multimedia authoring, a 21-inch (approx. 53 cm) monitor is common. Keep in mind that the physical size does not itself determine how many pixels are displayed. It only determines the amount of space available to display pixels. The number of pixels displayed in that space (the resolution of the video card) depends on the relationship between the dot pitch of the monitor and its physical size. Dot pitch Dot pitch refers to the spacing of dots on the monitor. Dot pitch is usually stated in fractions of a millimeter. For example, a dot pitch of .25 mm displays 4 dots per millimeter. The higher the number, the more widely spaced the dots. A lower number (more closely spaced dots) displays smoother edges and lines. It also crowds more information into a smaller area. If the dot pitch is too low, text may not be legible and objects may appear too small to be recognized. Thus, the dot pitch must be small enough to fit the resolution output by the video card onto the physical size of the monitor, yet large enough to be legible. For those taking e-learning, a moderate dot pitch of 0.27 mm is usually adequate. Those authoring e-learning may need a denser display and want a dot pitch of 0.24 mm. Display can make or break e-learning. Do not expect people to sit in front of a blurry, jittery, grainy display as eyestrain gives way to a migraine. Wiley Publishing, Inc. E-learning Tools and Technologies X Hardware for e-learning X 47 4 Hardware for e-learning Type of display There are two main types of monitor display units: CRTs and LCDs. CRT stands for cathode-ray tube and represents the big heavy boxes with television-like displays. LCD stands for liquid- crystal display and is found on laptops and the thin desktop monitors. Currently CRT displays (See the example shown at the left.) are less expensive, especially for larger screen sizes. And, the overall image quality may be a bit better and colors more accurate. LCD monitors are smaller, lighter, and generally brighter. Laptop computers would not be possible without them. They have a couple of other advantages: They do not flicker and their display does not get fuzzy over time. For desktop systems, LCD monitors are dropping in price and gaining favor, largely because they take up only about 10% as much desk space as an equivalent CRT monitor. A front view and a side view of an LCD monitor. For e-learning, either works fine, though cost may be an issue, especially if you need a large display area. Refresh rate The refresh rate of the monitor is the frequency at which it redraws the screen. This rate should be as fast as or faster than the refresh rate of the video card. In a CRT display, a refresh rate lower than 75 Hz leads to noticeable flicker. If possible, get a monitor with a refresh rate of 85 Hz or higher. Wiley Publishing, Inc. 48 W Hardware for e-learning W E-learning Tools and Technologies Remember that e-learners and authors of e-learning spend hours staring at a computer screen. Make this time comfortable and productive. Recommendations Pick your monitor and video card as a matched set. For those taking e-learning, a medium sized display of 16 inches (approx. 41 cm) with a moderate dot pitch of 0.27 mm should be adequate. Just make sure the monitor can support the resolution and refresh rate you specify for the video card. For those authoring e-learning, get as large a monitor as you can afford—at least 17 inches (approx. 43 cm) with a dot pitch of 0.24 mm. Again, make sure the monitor supports the resolution and refresh rate specified for the video card. If desk space is limited, opt for an LCD model. Optical drive: CD-ROM or DVD Most computers today come with a drive for reading, and perhaps writing, optical discs, such as CD-ROMs and DVDs. The physical size of these discs is standardized, but a large number of different types of discs exist, so it is important to ensure your computer can read and write the ones needed for your purposes. Since most programs come packaged on CD-ROMs, the ability to read the basic CD- ROM format is almost a requirement today. Much e-learning delivered over a network, however, does not require a CD-ROM. But a CD-ROM is handy for delivering content to those who are not always on a network or for making more media available than can be downloaded conveniently. Disc formats Here is a list of optical disc formats and how they might be used in e-learning. Format Specifications Use in taking e-learning Use in authoring e-learning CD-ROM Read-only 650 MB For media that would take too long to download For e-learning while not connected to the network Loading authoring programs CD-ROM stands for Compact Disc-Read Only Memory. DVD stands for Digital Video Disc or Digital Versatile Disc, depending on whom you ask. And CD- RW stands for Compact Disc-Rewriteable. Wiley Publishing, Inc. E-learning Tools and Technologies X Hardware for e-learning X 49 4 Hardware for e-learning Format Specifications Use in taking e-learning Use in authoring e-learning CD-A (Audio) Read-only 72 minutes For music samples in courses about music Reading in music for use in multimedia CD-R Write once and read 700 MB For submitting assignments too large to transmit by the network Backing up work files Exchanging files with other developers who are not on the network CD-RW Read, write, and rewrite 700 MB For submitting assignments too large to transmit by the network Backing up work files Exchanging files with other developers who are not on the network DVD-ROM Read-only 4.2 GB For media that would take too long to download For studying video, film, and music DVD-RW (used by most home DVD players) Read, write, and rewrite 4.2 GB For submitting assignments with video and other rich media Backing up work files Exchanging files with other developers not on the network DVD+RW (allows multi- session recording) Read, write, and rewrite 4.2 GB For submitting assignments with video and other rich media Backing up work files Exchanging files with other developers not on the network Each drive may support multiple formats. Make sure you know which it can read and write. Also consider the cost of blank recordable and rewriteable discs. Speed CD-ROM drives often specify speed as 24X, 32X, or something else X. These represent multiples of the basic speed at which a CD-audio disc is read; however, the numbers provide only an approximate indicator of actual performance reading data from the disc. For e-learning, any rating over about 12X should suffice. For those writing (burning) discs, the speed ratings can make a difference in how long it takes to record an entire disc of data. Obviously recording at 12X will take less time Burning a disc means recording on it, not throwing it in the fireplace, though that might be the fate it deserves. Wiley Publishing, Inc. 50 W Hardware for e-learning W E-learning Tools and Technologies than at 8X. For those authoring e-learning, you may want to invest in a disc that writes at a fast speed, so you don’t waste hours waiting to back up your day’s work or send test files to a client. Obviously if you work in video, the need for speed is even greater. Recommendations For those taking e-learning, get a CD-ROM drive. Period. For the near future, a CD- ROM drive is essential equipment. The speed of standard CD-ROM drives is more than adequate for anything learners might do, including accessing audio and video. For those authoring e-learning, specify a drive that also supports writeable discs (CD- R or CD-RW). If video is a big part of your efforts, splurge on a DVD+RW drive. Pay attention to the speeds at which these drives write, rewrite, and read data. For a CD-R or CD-RW, a write speed of 24X, a rewrite speed of 10X, and a read speed of 40X are adequate. DVD-RW and DVD+RW drives often read, write, and rewrite CD-R and CD-RW discs. Until DVD formats become more common and standardized, make sure others can read the discs you create. Audio Although text and graphics are sufficient for some forms of e-learning, more and more e-learning incorporates elements of sound, music, and voice. The quality of sound heard by learners is a product of the internal circuitry that converts digital data to analog sound signals and the external speakers that play that sound. Here is a view from the back of a computer. The boxed area shows the sound-out port for headphones and speakers, the line-in port for powered microphones, and the port for unpowered microphones. For simple uses of audio, the standard audio capabilities built into even low-cost computers are sufficient for most e-learning. All that is needed are inexpensive speakers. Advanced uses of audio, such as for language or music instruction, may require advanced sound capabilities and sophisticated speakers. Let’s look at some of the factors to consider. Wiley Publishing, Inc. E-learning Tools and Technologies X Hardware for e-learning X 51 4 Hardware for e-learning Number of speakers Sound systems produce three-dimensional images of sound by playing slightly different sounds through speakers at different locations near the listener. The first breakthrough in three-dimensional sound occurred as two-channel stereophonic music became popular in the 1960s. Most computer systems today play stereo sound, but other configurations are possible. f 2.1 Channels – combines a subwoofer with the standard left and right speakers. The subwoofer plays very low frequencies. Because human hearing cannot easily detect the direction of low-frequency sounds, the placement of the subwoofer is not critical. f 4 Channels – surrounds the listener with left and right speakers in front and left and right speakers behind. f 4.1 Channels – adds a subwoofer to the four surrounding channels. f 5.1 Channels – adds a subwoofer and a front-center channel to the standard 4-channel setup. These configurations are more common for home entertainment and gaming systems than for e-learning. In general, the standard two-channel stereo sound setup is adequate for e-learning. Some exceptions may occur. For teaching music or for sound effects, a 2.1 channel setup may give higher fidelity reproduction. If the subject matter is film, a 5.1 channel setup may be useful to duplicate the theater sound experience. Immersive, real-time simulations can also benefit from one of the 4+ channel setups that surround the listener. Power Most computer sound systems output a signal just powerful enough to play through headphones. For freestanding speakers, the sound must be amplified. That’s why most computer speaker sets include an amplifier. The power of the amplifier is customarily rated in watts. These ratings are notoriously unreliable and frequently exaggerated by disreputable vendors. Quality speakers that claim a 20-watt power rating may sound better than lesser speakers that claim a 50-watt rating. Unless you are teaching rock guitar (which needs to be loud) or classical violin (which needs minimal distortion), a modest power rating should be sufficient. Wiley Publishing, Inc. 52 W Hardware for e-learning W E-learning Tools and Technologies Headphones Most people taking e-learning prefer to do so privately. They don’t want to share the experience with the whole office. Their cubicle neighbors likewise appreciate the experience not being shared. If sound is part of e-learning, consider providing learners with headphones on which to listen. Consider two types of headphones: high- quality and lightweight. f High-quality headphones (pictured) typically feature full ear-muffs that surround the ears. They are more comfortable and block surrounding noise better; however, they are more expensive than lightweight headphones, ranging from $50 to $150 USD. f Lightweight headphones, such as those popularized by the Sony Walkman, provide excellent sound quality and fit easily in a briefcase with a laptop. They are quite inexpensive, about $25 USD. Unless your subject is sound or music, lightweight headphones are adequate for taking e-learning. For creating and editing voice, music, and sound effects, splurge on a good set of high-quality earphones. Microphones To capture voice and other sounds, you need a good quality microphone. This should be a simple decision, but often it is complicated by the different kinds of audio-in plugs found on computers. Type plug Type microphone required Line-in Powered microphone Microphone Unpowered microphone USB USB microphone Some corporate e-learners object to wearing headphones, fearing that managers and co- workers will think they are just listening to music. To solve this problem, one training department distributed headphones with a banner that draped across the back of the head, saying “Don’t bother me. I’m e-learning.” Wiley Publishing, Inc. E-learning Tools and Technologies X Hardware for e-learning X 53 4 Hardware for e-learning A second decision concerns the physical form of the microphone. Common forms of microphones used in e-learning include: Form of microphone Use Hand-held For high quality recording, especially when fixed to a stand rather than held in the hand. Headset Where both headphones and microphone are needed in one package. Especially convenient when the speaker moves about and uses hands. Also good for reducing ambient noise by keeping the microphone positioned close to the mouth. Lavaliere (pictured below) For unobtrusively recording the voice of a presenter or interviewee. For those taking e-learning, the standard sound capabilities of standard computers are adequate. Just provide inexpensive, lightweight headphones. There are several exceptions. If the subject is music, film, video, sound, or another subject where the quality of sound is crucial, upgrade the audio system to match that required for the subject. Microphones are not usually needed unless learners are studying a foreign language where they need to record phrases for playback and comparison. For those authoring e-learning, the audio system should be as good as that required by students. In addition, be sure to provide high-quality headphones. USB headphone/microphone combo and attached digitizing unit Line-in, powered, lavaliere microphone Wiley Publishing, Inc. 54 W Hardware for e-learning W E-learning Tools and Technologies If authors will be recording small segments of narration, a USB headphone/micro- phone combination is a good choice. These combos have a digitizing unit at the end of the USB cable where the audio from the microphone is processed directly before being captured by the computer. Because the USB unit processes the sound input, the quality of the sound is not dependent on the computer’s own audio circuitry. Network interface Computers hooked to a local area network need circuitry to communicate with the network. Such circuitry is called a network interface card (NIC). As a network connection is crucial for e-learning, this is a must-have component for computers not connecting via a modem. Most enterprise local area networks are Ethernet-based, where users connect by one of these NICs: f 10Base-T – communicates at 10 megabits per second f 100Base-T – communicates at 100 megabits per second (Fast Ethernet) f 10/100Base-T – communicates at 10 or 100 megabits per second depending on the speed of the network f Gigabit Ethernet – communicates at 1000 megabits per second If a NIC is not included with a computer, you can add an inexpensive 10/100Base-T card. The boxed area shows an RJ45 network connector on the back of a computer. The RJ45 plug is the most common type of Ethernet network connector. Another local area network technology is Token Ring. It requires a special Token Ring NIC. On laptops, the NIC may be built into the computer. Otherwise, the most common NIC for laptops is contained in a PCMCIA card (those business card-sized units) which fits into the laptop’s PCMCIA slot. If megas and bits are new to you, see appendix A. Wiley Publishing, Inc. [...]... hardware? connected directly to the network Wiley Publishing, Inc E- learning Tools and Technologies Networks for e- learning 69 The main LAN technologies are Ethernet and Token Ring Token Ring and Ethernet require different cables, hubs, switches, and other equipment A Token Ring LAN can be connected to an Ethernet LAN, but components of the two types cannot be mixed on a single LAN Let’s consider the merits... merits and place of each Ethernet (also known as IEEE 8 02. 3) is the most extensively used network technology The most widely installed Ethernet systems are called 10BASE-T and provide transmission speeds up to 10 megabits per second 100BASE-T is faster and provides transmission speeds up to 100 megabits per second Even faster is Gigabit Ethernet which enables speeds up to 1000 megabits per second And, yes,... like an internal Internet within an organization Web servers are connected to the LAN and serve Web pages in the same way as Web servers serve pages on the Internet However, these Web pages are only available to computers on the LAN—unless special arrangements are made We will discuss this in the section on connecting external users Typical intranet It contains a departmental Web server connected to... a department’s hub and an enterprise Web server connected to a switch serving the whole enterprise Content on the department server is typically private to that department, while content on the enterprise server is available to all on the network Wiley Publishing, Inc 5 Networks for e- learning Routers often include the features of a firewall—especially those used at the access point to the Internet—to... Internet technology If it is possible on the Internet, it is possible on an intranet For instance, departments can have their own servers in addition to a server shared with the rest of the enterprise Employees can collaborate using tools like NetMeeting, PlaceWare, and others Enterprises can easily implement internal e- mail Intranets enable training departments to offer Web-based e- learning to teach... and Technologies multinational enterprise connected to the Internet We will also talk about mobile learners and the special issues they pose Finally, we will turn to wireless networks to see how they fit TYPES OF NETWORKS Networks come in three sizes: small, large, and literally global Each scale of network uses somewhat different technologies The three sizes are more properly called local area networks... also feed live or recorded video into the computer The video conferencing camera records a small video image adequate for use in presentations and video conferencing sessions Such cameras are relatively inexpensive A video conferencing camera connected to a computer’s USB port Wiley Publishing, Inc E- learning Tools and Technologies Hardware for e- learning 59 Camcorders record higher quality video than... connecting to the Internet To reach your ISP and gain access to the content available on the Internet, you need a telecommunications connection A connection can be as simple as a telephone line or as sophisticated as a microwave tower These connections are crucial because they determine the speed, frequency, and ease with which learners can take e- learning Let’s consider some common types of connections... workstation’s efficiency and speed As long as you add the specified kind of processor, you seldom have to be concerned about component compatibility SERVER HARDWARE This chapter, however, does not expressly cover purchasing computers to run Web servers, database servers, collaboration servers, and other server systems The needs of server machines to host e- learning are different from the needs of computers for... the Web site into the address box of a browser Testing on a Web server is essential if the e- learning content uses any server-side scripting such as Active Server Pages (ASP) or JavaServer Pages (JSP) Behind the scenes, this network exchanges data using TCP/IP, which is required by the Web server A computer lab At some point, you may need to set up a computer lab where students can come and take e- learning . on the modem where the incoming telephone line is connected. You can connect a telephone to the other port. A modem may be needed for e- learners who take e- learning from computers at home or. for e- learning W E- learning Tools and Technologies Headphones Most people taking e- learning prefer to do so privately. They don’t want to share the experience with the whole office. Their cubicle. computers to run Web servers, database servers, collaboration servers, and other server systems. The needs of server machines to host e- learning are different from the needs of computers for