ICT: Data & Information

ICT: Data & Information

1. Data & the quality of data

   • Encoding
     • Change the form of data but keep it's meaning
     • Uses less memory to store
     • Faster for data entry
     • Easier to validate & less likely to miss-typed on data entry
   • Improved speed of access
     • ICT offers huge improvements in speed of access to data through the use of indexed databases & fast processors.
   • Using ICT for storing data.
     • Advantages
       • Far easier to back up & restore data than in non-ICT systems.
       • Data can be viewed & explored in many different ways (see Spotfire or Google Earth)
       • Data can be stored more securely, using encryption.
     • Disadvantages
       • ICT systems have a high initial cost & are expensive to replace & maintain.
       • Hacking & viruses can destroy & corrupt data.
       • Computerised systems are often complex & require training to use.

2. Avoiding GIGO

   • Possible sources of errors.
     • Data collected onto a data capture from a questionnaire may be recorded incorrectly.
     • Forms are designed carefully using unambiguous questions & boxes for each character.
     • Data may be incorrectly entered into a computer system. (transcription errors)
     • Verification methods (double keying, visual checks) or validation methods (range checks etc) may be used.

3. Validation

   • Range check. format check. check digit. presence check. batch totals. hash totals.

4. Verification

   • Parity checks. double keying. visual checks

5. Data logging & control

   • Data logging is the process of using a computer to record measurements from a sensor(s) over a period of time. Data is recorded through the computing process.

6. Sensors - input/output devices

   • E.g.input - sound, PIR (passive infared) - to detect motion, light, infared receivers (remote control), tilt, temperature.
   • E.g.output - speakers, heaters, LCD's, actuators and printers.

7. Control & monitoring

   • Feedback systems - e.g. - temperature control in a greenhouse.
   • Non-feedback systems - moving robotic arm with no expectation of anything stopping it.

8. Programming

   • Use programming structures such as if-then-else, loops & functions.
   • Input & output bits (binary digits) are set by input devices to switch output devices on and off.
   • Examples
     • Security sensors: PIR, light (laser - point straight at light sensor), pressure (place by doors), thumb print reader, sound(speakers, bell) lights.
     • Automatic doors: light, pressure, flexibility.
     • Traffic control systems: actuators.
     • car parking systems, greenhouse control systems, robotics, simulation(e.g.flight/driving)