Applications of Computer Systems

Some computer applications are safety-related, such as automatic pilot systems, and systems that control the operation of nuclear devices. The software in these systems requires a high degree of dependability, as human life will very often rely on the accurate and reliable operation of these systems. The development of this software is a very specialised field, where thorough testing is vital, and the resulting software is highly complex, with many inputs, and has to work in real-time.

Industrial, technical and scientific

Examples in this area are weather forecasting, computer aided design and manufacture, robotics and the use of computer generated graphics including animation. Features of these systems are that they usually involve complex mathematical calculations which have a large number of inputs and require fast processing speeds. The systems are very large, and therefore take up a large amount of backing storage. Robotics can be included under this heading. Robots can work 24/7, to a consistent standard without having breaks. They are more accurate than a human worker, but they lack the intelligence and versatility of a human. They can be put to work in areas which are dangerous to employees, but conversely, there may be cases when people do not trust the robot – safety critical systems. Although the initial cost of purchase is high, they will be relatively cheap to run as there are no salary costs, no cost for keeping them comfortable (heating and lighting), but they could be expensive to re-set for a new task. Most control systems will require real time processing.

Control systems

These include domestic, industrial and scientific applications. Feedback is an important issue here, where the output from a system will affect the next input and further stages in the processing. Sensors are used to measure physical properties such as pressure, rate of flow, temperature or humidity, and when processed, the data from the sensors will be used to operate actuators, which are devices that can be operated by signals from a computer or control system, e.g. open a pressure release valve. Automation is the use of a computer to carry out repetitive or intricate tasks normally done by people. Robotics are widely used in automation.

Expert systems/Artificial Intelligence

An expert system is an application program that attempts to carry out human reasoning in a specialised field, e.g. an “on line doctor”. An expert system is made up of three main parts: • The knowledge base – a bank of information of human expertise.

• a set of rules and facts – used to compare information entered with the knowledge base.

• A user interface – the communication between user and the system.

There would be a question and answer session, from which a likely outcome would be produced, and this would be followed by suggestions for solutions. e.g. With an on line medical system, users would be able to access a doctor without leaving the house, or without having to consult with a doctor over an embarrassing problem. A very large source of medical information (the knowledge base) could be accessed which would include diagram or pictures which could help with the self diagnosis. It could provide a second opinion for a patient, and be available 24/7. However drawbacks could include mis-diagnosis, fear of security issues, or an unreliable internet connection. The site would also be costly to set up and maintain, and there would need to be careful control over the information given out in order to avoid legal action. The use of these systems could also lead to the reduction in the number of doctors being employed.

Internet

The internet is a very useful tool, but has to be carefully used. It has a very wide range of information, but as there is no control over what is actually posted on the different web sites, any information downloaded and used needs to be verified against another source to ensure its validity. A search engine is an application accessed over the internet, that keeps indexes of web pages, and is used to search the World Wide Web for items of interest, using key words or phrases entered by the user, e.g. history students searching for specific dates in history. Some common applications of the internet include a web log – a personal diary kept on the web, and accessible to any web user, e.g. an actor could keep a weblog and post (make) entries so that his fans/followers could keep up to date with his current film or recording work. Features of a good web log are:

• Easy to navigate using hyperlinks.

• All links must be correct.

• Comply with established web standards.

• Accessible to a wide range of users, including those with physical or visual impairments.

• Based on sensible use of colour, fonts, graphics, etc.

• Instant messaging – allows real-time exchange of messages; users must be connected to the internet at the same time.

• VLEs - A virtual learning environment (VLE) is a software system or intranet designed to help teachers in the management of educational material for their students. A teacher might put teaching notes and exercises in the VLE. He/she might also encourage students to use the VLE for on-line discussions. • eCommerce – buying and selling on line, business transactions over networks.

• Music downloads – both legal and illegal sites on the internet for the downloading of music.

• On-line auctions – people are able to place bids on a website to purchase goods.

• On-line banking – users with access to the internet can check their balances, make payments and transfer money between accounts.

• On-line shopping – very useful for customers who cannot get out of the house.

Intranet

An intranet is a communication system providing similar services to the internet but entirely within a particular company. The main purpose of an intranet is to share company information, procedures and knowledge confidentially with employees. Some organisations will have both an internet site, and an intranet, and the information on these two sites will be very different, e.g. the information on the internet site will be for everyone to view, whereas the information on the intranet will be confidential. For example, with the college internet site, there is general information on campuses (contact details, opening times), term dates and courses, whereas the intranet site will have information only for current staff and students, such as contact details of staff, details for examination entries and so on.

Extranet

Some organisations may want part of their intranet site to be available to some authorised users. This part of the company’s intranet that is made available to outside users is called an “extranet”. The extranet forms an extension of a company’s intranet out onto the internet, to allow customers, suppliers and teleworkers to access the company’s private data and applications via the internet. Such facilities require very careful monitoring of security, and some may only allow read only access to data to help prevent accidental or malicious damage to the company data.

Computer Science


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