|
10/5/2009
|
| Information on these pages copyright of Ian Dufour | If you use this Encyclopedia regularly please make a donation to Tearfund |
| Numbers |
U
Skip down to Us
Where an individual user can utilise, at the same time, several computing platforms through which all the necessary information can be accessed whenever or wherever required. As well as the computing platforms, wireless and mobile technologies are also key enablers. See also wearable computing, body area networks, personal area networks, ad-hoc networks.
A wireless system that uses very wide bandwidth (typically in hundreds or thousands of MHz) and very low power spectral density (PSD). It transmits and receives extremely short pulses with a controlled duration, typically from a few tens of picoseconds up to a few nanoseconds. It has many uses outside telecommunications, including imaging, security and medical applications as well as military aspects such as radar (including 'seeing' through walls). It has potential uses in telecommunications for short-range (a few metres) high data-rate transmissions, such as automotive or body area networks or home area networks. Civilian communications uses are covered by the IEEE 802.15 series of standards.
See Ultra Wideband and its Capabilities (BTTJ, Vol 21 No3).
The ability to upgrade plant or a service to add capability or features at a later stage.
Can apply to the local-loop or to services. Local-loop unbundling (LLU) refers to a commercial structure, invariably supervised by a Regulator, whereby a dominant telecommunications operator will share the local-loop infrastructure with other operators using pre-determined fees and conditions. It can operate at various levels of sharing of service and infrastructure. An unbundled service is one where it is independent of other services and is the opposite of bundled services where several services are combined into a single service package.
Generally applied to a transmission path where the signal can pass in one direction only.
Uniform Resource Locator (URL) - Sometimes known as Universal Resource Locator
A Uniform Resource Locator (URL) is a compact and more easily remembered representation of the location and access to a resource available via the Internet - such as a web-page. It is one of the basic building-blocks of the world-wide web (Internet). The syntax and semantics were originally proposed by Tim Berners Lee et al in IETF RFC 1738 in 1994,varied and issued later by others as RFC 1808.
A URL is one kind of Uniform Resource Identifier (URI), which is a more generic description of various names and numbers on the Internet.
A URL is most widely known in the form http://www.bt.com/bttj but there are many variants of which a few are covered here. The part before the colon is called the scheme and would typically be http or ftp or a small range of lesser known ones. The // indicates the start of the network location and parts after a / (which may or may not be present and of which there are several variants) indicate the location at the destination. The network location or domain name will always comprise at least two parts separated by a "." . The last part will be of the form .com, .net, .biz etc.
The convenient names used by most URLs actually have to be translated into an IP address in the form 132.146.100.100 where each of the four numbers are in the range 0 - 255. This translation is carried out by a domain name server (DNS) - one of many computers somewhere in the Internet that maps the URL name to the IP address and then directs the request to the right computer. This latter function is not unlike an Intelligent Network number translation.
URL and IP addressing is much more complex than this simple explanation and a number of variants are exploited for spam and fraud. For example it is permitted to put username:password in front of the network location followed by the "@" symbol. If the site concerned does not actually need the user name and password then everything between the // and @ is ignored. This can be exploited by sending someone an e-mail with a response URL using, for example, mybank.com in between the // and @ to make people think that they are responding to their bank and trick them into giving away account details. Similar tricks are used to get people to click on links to sites which will download viruses.
The opportunities for fraud and deception are further exploited by the ability of most browsers to handle a variety of representations of the address. Thus most can handle the URL, the IP address in xxx:xxx:xxx:xxx format and also in 4 other formats: octal (base 8); hexadecimal (base 16); dword (two binary words of 16 bits expressed in decimal); and any mixture of them.
A computer operating system supporting multi-users and multi-tasking and written in the C language. Originally developed by Bell Telephone Laboratories for telephone exchange processing applications it found the majority of its applications in the computer industry. It is a predominantly open system that can be improved or enhanced by anyone but this has led to some developments being proprietary. There are therefore numerous variants many of them commercially available (e.g Sun Solaris, Macintosh OS X) and it has formed the basis of other open code initiatives, notably Linux.
This is an intermediate stage between network functions and the means of billing and the functions performed in the area are:
- Interfacing with network and application platform components to collect usage information. (Telephony switch vendors often use proprietary protocols for transfer of this data).
- Conversion of the usage data into the form required by those systems which are to subsequently receive the data. This can include correlation of separate usage records from the network to generate a single record for the receiving systems, or enhancement of the data by inclusion of data from another source (eg enhancing a telephony call record by including a customer account number, based on look-up of the phone number in a customer database).
- Optionally, the mediation system can perform archiving of usage records, or expediting certain types of usage records through it (eg for ‘hot billing’).
Interfacing to systems receiving the data. Primarily the mediation platform will interface to the billing system, but may also have interfaces to systems performing statistical analysis (eg for marketing or fraud analysis).
A general description of the look and feel of the interface between a human and an object, often a machine. Sometimes known as an HMI (human machine interface) or a MMI (man machine interface). The book or screen you are viewing this from is a user interface, as is part of the software that lies behind any screen-based display. Where the screen-display includes graphics rather than only characters it is referred to as a graphical user interface or GUI often pronounced "gooey".
Utilisation (of plant: cables, switching equipment etc)
A measure of the amount of plant that is in use for service provision compared to the total capacity. The remainder is spare plant. It is applied to cable capacity, switching capacity, power plants etc. It can also apply to the proportion of the time of people booked to project work - usually revenue generating.
END