Video RAM (VRAM) means in general all forms of random access memory (RAM) used to store image data for a computer display. All types of video RAM are special arrangements of dynamic RAM (DRAM). Video RAM is really a buffer between the computer processor and the display and is often called the frame buffer. When images are to be sent to the display, they are first read by the processor as data from some form of main (non-video) RAM and then written to video RAM. From video RAM (the frame buffer), the data is converted by a RAM digital-to-analog converter (RAMDAC) into analog signals that are sent to the display presentation mechanism such as a cathode ray tube (CRT). Usually, video RAM comes in a 1 or 2 megabyte package and is located on the video adapter card in the computer. Most forms of video RAM are dual-ported, which means that while the processor is writing a new image to video RAM, the display is reading from video RAM to refresh its current display content. The dual-port design is the main difference between main RAM and video RAM.
An entity relationship model, also called an entity-relationship (ER) diagram, is a graphical representation of entities and their relationships to each other, typically used in computing in regard to the organization of data within databases or information systems. An entity is a piece of data-an object or concept about which data is stored.'
SDLC MODEL:
Sensor based network:
A wireless sensor network is a group of specialized transducers with a communications infrastructure for monitoring and recording conditions at diverse locations. Commonly monitored parameters are temperature, humidity, pressure, wind direction and speed, illumination intensity, vibration intensity, sound intensity, power-line voltage, chemical concentrations, pollutant levels and vital body functions.
A sensor network consists of multiple detection stations called sensor nodes, each of which is small, lightweight and portable. Every sensor node is equipped with a transducer, microcomputer, transceiver and power source. The transducer generates electrical signals based on sensed physical effects and phenomena. The microcomputer processes and stores the sensor output. The transceiver receives commands from a central computer and transmits data to that computer. The power for each sensor node is derived from a battery.