disadvantages of using a wireless network

... spoken. One of the main reasons for special interest of foreign language educators in distance learning is that technology makes it Advantages and disadvantages of using computer network Tạp ... such as multimedia, email, electronic journals, databases, World Wide Web, chat, audio and video conferencing etc. This paper will investigate both advantages and disadvantages of incorporating ... learn vocabulary while reading. In addition, quite a few authentic language journals such as The Modern Language Journal, The Internet TESL Journal etc. are available on the net and databases....

Ngày tải lên: 05/03/2014, 12:20

... facilitates tracking and battery drain at- tacks. Although activation signals are very simple, they can convey a minimal amount of bits. Thus, using a long packet format with encryption and authentication ... to get a match rate of more than P = 1%. We note that this calculation is based on the unrealis- tic assumption that all 38 billion cars are co-located, and are using the same modulation and coding ... determine how many cars R can be on the road in the US with a guarantee that there is a less than P chance of any two or more cars having the same ID-set, is a classical birthday problem calculation: R...

Ngày tải lên: 23/03/2014, 10:20

... retransmissions and thereby increase the perfor- mance of TCP over wireless networks. List of Abbreviations ACL: accuracy of congestion loss; ARL: accuracy of random loss; APR: accuracy of packet ... timestamp based available bandwidth esti- mation (TABE) and congestion warning scheme. To estimate the available bandwidth, TCP Jersey follows the same idea of TCP Westwood’s rate estimator to ... especially in the case of packet reordering rather than using an algorithm that samples one RTT p er window of data. The reason is, in the presence of spurious fast retransmits, TCP is likely to have...

Ngày tải lên: 21/06/2014, 02:20

... Service as a Network Systems Engineer bringing his knowledge of the desktop platform and a general understanding of a broad range of technologies in areas such as remote access, ATM, frame relay, and ... central location so that someone awaiting a delivery can log into the Web site and get accurate information regarding the status of a package. Using Wireless for Public Safety Public safety applications got ... 25 Modulating a Radio Signal 27 Propagating a Strong Radio Signal 34 Understanding Signal Power and Signal-to-Noise Ratio 35 Attenuation 36 Rain Attenuation 39 Bouncing 39 Refracting 41 Line of Sight...

Ngày tải lên: 16/10/2013, 13:15

Ngày tải lên: 18/10/2013, 12:15

Ngày tải lên: 18/02/2014, 04:20

... generation table in the paper) associated with each station. Basically, each station is assigned a special label, and it is selected as a forwarding node if its label is a prefix of the label of ... P (Parking state) are stations that are synchronized with the master but are not participating in any data exchange. Independent piconets that have overlapping coverage areas may form a scatternet. ... that either a shared multicast tree be used for all sources or that a separate multicast tree be established for each source. Using a shared multicast tree has the disadvantage that packets are...

Ngày tải lên: 03/06/2014, 01:08

... Waves 24 Anatomy of a Waveform 25 Modulating a Radio Signal 27 Propagating a Strong Radio Signal 34 Understanding Signal Power and Signal-to-Noise Ratio 35 Attenuation 36 Rain Attenuation 39 Bouncing ... generator. Faraday’s initial findings still serve as the basis of modern electromagnetic technology. Around the same time that Faraday worked with electromagnetism, an American professor named ... of the desktop platform and a general understanding of a broad range of technologies in areas such as remote access, ATM, frame relay, and wireless. In addition, his background includes con- sulting...

Ngày tải lên: 14/08/2014, 14:20

... the signal cannot penetrate metal. Assume you have a metal sphere. As an EM wave hits the leading edge of the sphere, it acts like an antenna, and the wave induces a voltage in the metal.This voltage ... but remember, a wireless network typically is not a stand- alone network. For example, a wireless local area network (LAN) is composed of access points, antennas, and wireless PC cards.The only connection ... metal among the materials. Metal is a special case for penetration of EM waves. Let’s first consider how an antenna works. At the transmitting end, a cable is hooked to an antenna.The signal travels...

Ngày tải lên: 14/08/2014, 14:20

... mounted flat on a wall, yet still have the proper- ties and gain of a directional antenna. Figure 2.17 shows a planar array antenna. www.syngress.com Figure 2.17 Planar Array Antenna and Associated ... antennas. Planar Array Antennas Planar array antennas are similar in concept to Yagi antennas except all elements, both active and parasitic, lie in the same plane.This results in a flat antenna that can be mounted ... Directional Beam Pattern Side View Planar Phased Array Antenna Direction of Beam Antenna G Directional Beam Multiple Antenna Elements Shown with Dipole Antennas Top View Steerable Beam Planar Array...

Ngày tải lên: 14/08/2014, 14:20

... necessary to obtain a range. In North America, South America, the Caribbean, and sub-Saharan Africa, the organization responsible is the Address Registry for Internet Numbers (ARIN), which can be ... the organization is the Asia/Pacific Network Information Centre (APNIC), which can be found at www.apnic.net. Q: When using PAT, how can I accommodate all the necessary ports? A: Approximately ... A dynamically routed network is capable of facilitating these types of changes. How is an algorithm aware that the network has changed? Remember that an algorithm is just one component of a routing pro- tocol.There...

Ngày tải lên: 14/08/2014, 14:20

... checked against a database of allowed MACs located on the wired network. This typically provides a good level of security, and is best used with small WLAN networks.With larger WLAN networks, administering ... supporting hardware and software that you have called for in your network design.Although this may be an exhila- rating time, where concept enters the realm of reality, it is vital that you manage this ... device wants to access the Internet, it first needs to access a WAP gateway.This gateway, which is actually a piece of software and not a physical device, optimizes the content for wireless applications....

Ngày tải lên: 14/08/2014, 14:20

... often their greatest weaknesses.The same can be said when examining the attributes of a wireless network. Both mobility and ease of access are touted as some of the greatest characteristics available ... landscape perspective, we can easily see how physical obstructions may affect signal quality and overall throughput.As such, placement of antennas, angles of reception, antenna gain and distance ... distinct channels within that wireless topology. Similarly, adja- cent channel spacing and active channel separation play an important role when planning and deploying a wireless network. These aspects refer...

Ngày tải lên: 14/08/2014, 14:20

... Buildings Elevators Mechanical Room Communications Room Conference Room Office Office Office Office Office Office Office Office Office Office Office Office Office Office Office Break Room AP AP 152_wan_06 6/21/01 3:24 PM Page 219 Designing a Wireless Enterprise ... clothing departments, a shoe department, a baseball/soccer department, a golf department, a sea- sonal department, and a sunglasses department. Generally, the most active of all the first-floor departments ... the network development phases of planning and design. Obtaining a Physical Map The physical map contains information about the placement of the dif- ferent areas of the store, information about...

Ngày tải lên: 14/08/2014, 14:20

... athletic, and academic areas of the campus. At this time, only three academic areas are addressed.The planned network must be easy to adapt as these areas of study increase or change. For example, ... Athletic department may have functional groups of coaches, players, and the press.The Administrative department may designate a Financial functional group, as well as Student Records and Management ... as encryption and password allocation to ensure the concept of fair play and remain within NCAA rules and guidelines. Both teams must have equal capabil- ities to meet NCAA rules.Visiting coaching...

Ngày tải lên: 14/08/2014, 14:20

Ngày tải lên: 14/08/2014, 14:20

Ngày tải lên: 14/08/2014, 14:20

Ngày tải lên: 14/08/2014, 18:22

Ngày tải lên: 14/08/2014, 18:22