This section offers more information on terms and technical details that could not be explained within the tutorial pages.
- HTTP Protocol
- IP Address
- (IR) Infra-Red Sensor
- Java Programming Language
- Mathematical Model
- (PIR) Passive Infra-Red Sensor
- TCP/IP Protocol
- XML Language
HTTP is an abbreviation for HyperText Transfer Protocol. This is the set of rules which determine how web pages are transmitted and interpreted by your web browser (e.g. Internet Explorer or Firefox). For example, when the user enters a web address such as www.match-project.org.uk, HTTP sends this address as a Uniform Resource Locator (URL) to the web server. The server retrieves this web page and transmits it back to you.
An IP address means Internet Protocol Address.
Every computer on a network can be identified by its unique 16 digit number combination. This combination of numbers can be thought of as the equivalent of a street address. Just as each house has a unique address within a street, a computer also has a unique address on a network.
IP addresses have a format such as '62.269.350.238'. To find out the IP address of your computer, go to www.whatsmyip.org.
IR is short for Infra-Red. This form of sensor uses a transmitter-receiver system to send an invisible infra-red light beam through the air along a set path, e.g. across a doorway. When the light beam is interrupted, e.g. someone passes through the doorway, a signal is sent to the system. This can cause some function to be activated, e.g. to trigger an alarm.
Java is a widely used programming language created by Sun Microsystems. Java is unusual in that programs are not directly translated into a code that a computer can execute. Instead they are translated into Byte Code. This is interpreted and executed by a Java Virtual Machine. The reason for this approach is that the same Java code can then run on many different types of computers.
The commonest Mathematical Models used by the MATCH Project are Hidden Markov Models.
A Hidden Markov Model is a statistical model which is designed to determine unknown numerical values from those which we do know.
Consider a corridor with a T-shaped junction at its end. A person walking down that corridor may turn either left or right, with a 50% probability of either. If, over a period of time, we record how often a person walked left or right, this will directly affect the probability values of these choices. The Hidden Markov Model can be used to guess that a user is more likely to turn left than turn right.
(PIR) Passive Infra-Red Sensor
PIR is short for Passive Infra-Red. This form of sensor is usually a small box that sits in the corner of a room. The sensor works by detecting an increase in the level of infra-red radiation within a room. Infra-red radiation is otherwise known as heat, so body heat can trigger the sensor. An example of how an alarm may go off is a warm body passing a cold wall. The sensor notices the difference between the two and an alarm will sound.
The term 'passive' means that the sensor does not emit any form of signal - it just notes changes in the enviroment.
TCP/IP means Transmission Control Protocol / Internet Protocol.
This is what is known in the computing world as a communications protocol - a standard set of rules for communicating. The set of rules dictates how to transmit data over a network. TCP/IP is a fundamental set of standards for communication over the Internet.
XML is short for Extensible Markup Language. It is a computer language which can be used to add structure to data, making it simpler to work with and understand. XML uses Tags around data to indicate what the data means.
