The Way in Which ICT is used

Modelling Application

A simulation is the creation of a model of a real system in order to study the behaviour of the system. The model is computer generated and is based on mathematical representation.


The advantages / the benefits / the reason of using computer as simulation:

1. Less expensive.
2. It is saver to run a simulation than the real one.
3. It is nearly impossible to try out some tasks in real life because of the high risk.
4. With simulation, various scenarios can be tried out in advance.
5. It is faster to do a simulation than the real thing

The limitation:

1.  Only as good as the data used (not representing the real-life situation).
2. It can be very expensive to set up.
3. It often requires specialist software.
4. It frequently requires very fast processors/computer system.

Monitoring Application

In monitoring applications, the computer simply reviews the data from the sensors (by comparing it to data stored in memory) and updates its files and / or gives a warning signal if the values are outside given parameters.
Examples:

1. monitoring a patient's vital signs in a hospital.
2. monitoring a scientific experiment in a laboratory.
3. a burglar alarm system
4. environmental  monitoring (e.g. oxygen levels in a river)

The advantages:

• the computer will not forget to take reading.
• the reading will tend to be more accurate
• the computer's response time is much faster.
• it is done automatically.
• it can work 24 hours every day (24/7).

 Monitoring process example: monitoring a patient's vital sign in a hospital

1. Sensor read key vital signs.
2. The data from the sensors is converted into digital using an ADC.
3. The data is stored in computer's memory.
4. The computer compares the data from sensors with the value stored in its memory.
5. The results are output on a screen in the form of graphs and / or digital read-outs.
6. An alarm is activated if any of the data is outside acceptable parameters.
7. The system continues to monitor the patient until the computer is turned off.

Controlling  Application

In control application, the computer again reviews the data from sensors (by comparing it to data stored in memory). But if the values are outside the given parameters it takes action to try and get the value within acceptable ranges.
Examples:

1. controlling a chemical process.
2. controlling a nuclear reactor.
3. controlling a greenhouse environment.
4. controlling a central heating system.
5. controlling a set of traffic lights.

The advantages:

• The response time is much faster.
• It is safer, as some processes are dangerous, so it is better to control it from a distance.
• Another common advantages of using computer like more accurate, can work 24/7 or more reliable.

Control process example: a greenhouse environment
There are five different sensors could be used to control a greenhouse environment: humidity, moisture, temperature, pH and light sensors. The following process is based on humidity sensor.

1. The humidity sensor sends a signal to an ADC. 
2. The ADC sends a digital signal to the computer.
3. This compares the input with stored values and decides what action needs to be taken.
4. If humidity is too high, the computer sends a signal to a DAC to operate the motors to open windows thus reducing the humidity.
5. If it is too low, the computer sends a signal to open valves to spray water into the air. 

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