What is the Contextual Awareness.....?
Now it is necessary to determine how something can be aware of such context we have declared.The first context-aware implementations were developed by collected locational information to improve efficiency of systems. For instance: a telephone system which patches through a call directly into a room where a requested person currently is. Since then, there have been many attemps to use and react to contextual information.
Also, One challenge of mobile distributed computing is to exploit the changing environment with a new class of applications that are aware of the context in which they are run. Such context-aware software adapts according to the location of use, the collection of nearby people, hosts, and accessible devices, as well as to changes to such things over time. A system with these capabilities can examine the computing environment and react to changes to the environment. Three important aspects of context are: where you are, who you are with, and what resources are nearby. Context encompasses more than just the user’s location, because other things of interest are also mobile and changing. Context includes lighting, noise level, network connectivity, communication costs, communication bandwidth, and even the social situation.whether you are with your manager or with a co-worker. We are investigating these kinds of applications using the PARCTAB, a small hand held device which uses an infrared-based cellular network for communication. The tab acts as a graphics terminal, and most applications run on remote hosts. This design exploits remote processing power to achieve a smaller and cheaper device. For input, the tab has three finger-operated buttons on the grip, and a touch sensitive screen. For output, the tab has a 128x64 pixel display and a piezo electric speaker. When wired with an infrared transceiver, a room becomes a cell in the infrared network. The bandwidth available for all tabs in a cell is 19,200 bps. The combination of room-sized cells, and tabs that periodically send an identifying packet (Beacon), permits accurate location monitoring even when the device is not being used. The system notifies applications of location changes, and also provides location information to a public service that collects and redistributes information about objects and their locations . Other systems might learn about location by other means: for example, by using global positioning (GPS) or dead-reckoning, or simply by monitoring workstation interactions. An alternative to the tab system’s locating scheme – where the mobile devices beacon – is a scheme where stationary devices broadcast a message identifying their fixed location. Mobile computers can listen to these broadcasts to determine their own locations.
