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Glossary for the entire site, across all courses and subjects.


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W

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Wavelength is the physical distance spanned by one complete cycle or wave of an alternating signal as it travels through space. The term wavelength can be applied to many types of wave, e.g. audio, radio, light, etc, but is generally only applicable to a wave of a single frequency, such as the RF carrier transmitted by a mobile phone. Wavelength (l), usually measured in metres between the adjacent peaks or troughs of consecutive waves, is related to frequency (f) and propagation velocity (v) by the equation l = v / f. Note that the propagation velocity depends on the type of wave and the material through which it passes: radio waves travel at the speed of light, but audio waves at the speed of sound
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A computer programme designed to produce web pages for a web site.
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A web page or webpage is a resource on the World Wide Web
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A collection of related pages (web pages) of information, owned and maintained by the same organisation or individual, and published on the Internet. It is relatively straightforward for schools and individuals to create a web site.
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Like a conventional whiteboard, except that the images from the computer are projected onto the board and can be controlled and adjusted on screen using a stylus. Can be used in whole class teaching.
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Also known as: WAP identity module WIM (WAP identity module) is a security module that provides a more secure environment when using WAP related applications and services on a mobile device via a WAP gateway. A WIM allows the user to store certificates and digital signatures
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Also known as: WAP WAP (Wireless Application Protocol) is a common global standard, which defines the way in which Internet communications and advanced non-voice services are provided on wireless mobile devices, such as digital mobile phones and Personal Digital Assistants. The current version of this protocol is WAP 2.0, and it is fast becoming the standard way for mobile devices to access Internet services, by communicating with a server installed in the mobile phone network. A mobile device can therefore combine telephony services with the limited capacity of mobile terminal displays, and so provide the user with a microbrowser. A WAP enabled phone provides interactive access to the Internet, and to services such as online news and information, e-commerce transactions, online banking, e-mail messaging, Internet Relay Chat (IRC), and a host of new services still in development. Subscribers use WAP to access websites and pages that have been converted for WML (Wireless Markup Language), which are stripped down to their basic text format, and this is more suitable for the limited display capabilities of mobile devices. WAP works with multiple standards and is supported by most modern mobile networks, such as GSM, GPRS, and UMTS, and in the future equipment and networks that use WAP will be more compatible, regardless of the manufacturer. WAP is the mobile equivalent of HTTP (HyperText Transfer Protocol), and has been developed through the cooperation of the world's major telecommunications and software companies, their activities being co-ordinated through the WAP Forum. The WAP Forum has a website at www.wapforum.org. Some manufacturers claim that their handsets have WAP 2.0 browsers; this is often a re-branding of an XHTML-MP browser, the version number representing XHTML replacing WML for mobile content markup. An alternative system standard to WAP is i-Mode
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Wireless Phone is another name for a mobile phone. The word 'wireless' refers to the fact that the phone is actually a small radio transceiver, which communicates with the mobile telephone network by transmitting and receiving radio signals through the air without using wires. Although the various types of mobile phone, cell (cellular) phones, and car phones are all wireless devices, the cordless phones used at home are not considered wireless, as their base units are connected by wires to the network
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The ability to enter, edit, manipulate, store and print pages of text using a computer. Modern word processors have desktop publishing capability.
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The vast collection of information which has been published on the Internet in the form of web pages.
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This consists of a strap fitting around your chest that contains a radio that transmits your heartbeat to a wristwatch monitor. Heart monitors can be programmed to beep if your pulse rate moves outside your target zone.
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world wide web
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what you see is what you get
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X

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Also known as: Ymodem Y-Modem is an error-correction protocol used in the transfer of serial data files between modems. Y-Modem is based on the earlier X-Modem protocol, but has the additional feature of being able to cope with a batch transmission mode, in which a number of files can be sent with one command. For greater efficiency Y-Modem can also handle data with a variable block size of up to a maximum 1024 bytes (1 kB). During transmission, the size of text and binary files is included in the Y-Modem header, so that the exact file length will be retained after transfer. The error detection method in Y-Modem is cyclic redundancy check (CRC). A later version of Y-Modem, Y-Modem-G, transmits data in a continuous stream and does not acknowledge the blocks successfully received; it is only the blocks with detected errors that cause a negative acknowledgement (NAK), thus prompting the resending of data
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XHTML (a merger of XML and HTML) is an updated HTML standard introduced to help tidy up all the developments and additions to original HTML. Over the years, different browsers added features and offered increased functionality, which all had their own proprietary manifestation in HTML. This led to a mish mash of tags and markup that often led to web authors putting in duplicate attributes and code in order to make sure that a page looked the same in different browsers browsers. XHTML is a unifying standard from the W3C that brings the XML benefits of easy validation and troubleshooting to HTML, which not only helps developers but also makes the pages easier to read for programs such as mobile browsers. There are three variations of XHTML, the most common of which is Transitional. XHTML Transitional is a stepping stone from the deprecated HTML standardsL, and as such is fairly permissive, allowing many old and proprietary attributes, although Transitional stipulates that all tags must have both opening and a closing markup and be correctly nested. XHTML Strict is a more rigourous standard that removes all the ’chaff’ gathered by HTML not ruled out in Transitional, and is what web authors should strive toward. Finally, XHTML Frameset is similar to XHTML Transitional, but allows for the use of frames.
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extensible markup language
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Y

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Also known as: Ymodem Y-Modem is an error-correction protocol used in the transfer of serial data files between modems. Y-Modem is based on the earlier X-Modem protocol, but has the additional feature of being able to cope with a batch transmission mode, in which a number of files can be sent with one command. For greater efficiency Y-Modem can also handle data with a variable block size of up to a maximum 1024 bytes (1 kB). During transmission, the size of text and binary files is included in the Y-Modem header, so that the exact file length will be retained after transfer. The error detection method in Y-Modem is cyclic redundancy check (CRC). A later version of Y-Modem, Y-Modem-G, transmits data in a continuous stream and does not acknowledge the blocks successfully received; it is only the blocks with detected errors that cause a negative acknowledgement (NAK), thus prompting the resending of data

Z

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Also known as: Zmodem Z-Modem is an error-correction protocol used in the transfer of serial data files between modems. Z-Modem is a faster successor to Y-Modem and has better error checking capability. Modems using the Z-Modem protocol send data in 512-byte blocks or packets, and the error detection method is cyclic redundancy check (CRC). Like Y-Modem, Z-Modem has the capability of handling batch transmission (sending a number of files with one command) and variable block sizes of data. Z-Modem is also similar to Y-Modem-G, because it sends data in a continuous stream, and does not require a positive acknowledgement (ACK) for successfully transferred blocks of data. However, if an error is detected in a received block, a negative acknowledgement (NAK) is returned to the sender and the block resent. Z-Modem differs from the earlier protocols in that it is able to recover after a "crash", i.e. when a transmission is cancelled or for some other reason interrupted, the transmission may be restarted without resending the previously transferred blocks of data

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