Caribbean Secondary Education Certificate - Information Technology/Applications and Implications of I.C.T
Contents
Applications and Implications of I.C.T
What is Data Communications?
The distance over which data moves within a computer may vary from a few thousandths of an inch, as is the case within a single IC chip, to as much as several feet along the backplane of the main circuit board. Over such small distances, digital data may be transmitted as direct, two-level electrical signals over simple copper conductors. Except for the fastest computers, circuit designers are not very concerned about the shape of the conductor or the analog characteristics of signal transmission.
Frequently, however, data must be sent beyond the local circuitry that constitutes a computer. In many cases, the distances involved may be enormous. Unfortunately, as the distance between the source of a message and its destination increases, accurate transmission becomes increasingly difficult. This results from the electrical distortion of signals traveling through long conductors, and from noise added to the signal as it propagates through a transmission medium. Although some precautions must be taken for data exchange within a computer, the biggest problems occur when data is transferred to devices outside the computer's circuitry. In this case, distortion and noise can become so severe that information is lost.
Data Communications concerns the transmission of digital messages to devices external to the message source. "External" devices are generally thought of as being independently powered circuitry that exists beyond the chassis of a computer or other digital message source. As a rule, the maximum permissible transmission rate of a message is directly proportional to signal power, and inversely proportional to channel noise. It is the aim of any communications system to provide the highest possible transmission rate at the lowest possible power and with the least possible noise.
Communications Channels
A communications channel is a pathway over which information can be conveyed. It may be defined by a physical wire that connects communicating devices, or by a radio, laser, or other radiated energy source that has no obvious physical presence. Information sent through a communications channel has a source from which the information originates, and a destination to which the information is delivered. Although information originates from a single source, there may be more than one destination, depending upon how many receive stations are linked to the channel and how much energy the transmitted signal possesses.
In a digital communications channel, the information is represented by individual data bits, which may be encapsulated into multibit message units. A byte, which consists of eight bits, is an example of a message unit that may be conveyed through a digital communications channel. A collection of bytes may itself be grouped into a frame or other higher-level message unit. Such multiple levels of encapsulation facilitate the handling of messages in a complex data communications network.
The message source is the transmitter, and the destination is the receiver. A channel whose direction of transmission is unchanging is referred to as a simplex channel. For example, a radio station is a simplex channel because it always transmits the signal to its listeners and never allows them to transmit back.
A half-duplex channel is a single physical channel in which the direction may be reversed. Messages may flow in two directions, but never at the same time, in a half-duplex system. In a telephone call, one party speaks while the other listens. After a pause, the other party speaks and the first party listens. Speaking simultaneously results in garbled sound that cannot be understood.
A full-duplex channel allows simultaneous message exchange in both directions. It really consists of two simplex channels, a forward channel and a reverse channel, linking the same points. The transmission rate of the reverse channel may be slower if it is used only for flow control of the forward channel.
Information Systems
The characteristics of an information system are:
- The Organisation of data into information:
For data to be made meaningful it must have a purpose. The purpose of the stored data should reflect the purpose and type of the information system. Data needs to be processed and organised before it becomes information. Organising the data will most likely involve the processes of sorting and filtering (classifying) before it can be analysed and stored for later retrieval. Data dictionaries are used to help organise the data.
- Ability to Analyse the Information:
Once the data has become information it needs to be analysed to make the most of the information stored. Analysis of databases is done through the tools of queries and reports.
The purposes (Functions) of an Information System are:
- Processing Transactions:
A transaction processing system (tps) collects, stores, modifies and retrieves the transactions of an organization. Examples of such systems are automatic telling machines (ATMs), electronic funds transfer at point of sale (EFTPOS – also referred to as POS). There are two types of transaction of processing:
- Batch processing:
where all of the transactions are collected and processed as one group or batch at a later stage.
- Real-time processing:where the transaction is processed immediately.
- Provide Users with Information About an Organisation:
This information system provides information to managers about the performance of their organisation. It may involve information about payroll, an inventory, stock list or budgets and would require the printing of information in the form of reports normally based on queries. Examples of this kind of system are management information systems (MIS) and executive information systems (EIS).
- Help Decision-making:
This type of system is also referred to as a decision support system (DSS). A decision support system will assist people to make decisions by providing tools to analyse the information stored in a system. A DSS will provide a mathematical model of the variables affecting the decision and then point directions for actions that should be taken. One such example is the system that used by stockbrokers, which chart fluctuations in price and then make buy or sell recommendations dependant upon the parameters predefined by the stockbroker. Many DSS will allow managers to ask “what if” style questions and then see what would happen. This is particularly useful when the variables are limited and predictions can be safely based on what is known. A DSS is only as accurate as the mathematical model used.
Another kind of DSS is an expert system. Expert systems are designed to help make decisions that would involve someone highly qualified an experienced in that field. An example of an expert system is one used by doctors to help diagnose patients or prescribe drugs.
- Manage Information used Within an Organisation:
This system is designed to provide an efficient way of dealing with information within an office environment. Another name for this an office automation system. This will include word processors, spreadsheets, databases and email. An example of an office automation system is Microsoft Office.
- Examples of Database Information Systems
Most Information systems store data in a database and are referred to as Database management Systems. Examples referred to in the syllabus include:
A school database holding information on teachers, subjects, classrooms and students
The Roads and Traffic authority holding information on automobiles and holders of driver’s licences
Video stores holding information on borrowers and videos.
Components of Information Systems
The components of an information system are:
- People
There are many roles for people in information systems. Common ones include:
- Systems Analyst
- Programmer
- Technician
- Engineer
- Network Manager
- MIS (Manager of Information Systems)
- Data entry operator
- Equipment
When you think "equipment", immediately think "Hardware AND Software"
- Procedures
A procedure is a series of documented actions taken to achieve something. A procedure is more than a single simple task. A procedure can be quite complex and involved, such as performing a backup, shutting down a system, patching software.
- Data
The raw, unorganised, discrete (separate, isolated) potentially-useful facts and figures that are later processed (manipulated) to produce information.
Types of Information Systems
Information systems are constantly changing and evolving as technology continues to grow. Very importantly the information systems described below are not mutually exclusive and some (especially Expert Systems, Management Information Systems and Executive Information Systems are can be seen as a subset of Decision Support Systems). However these examples are not the only overlaps and the divions of these information systems will change over time.
At present there are five main types:
- Transaction Processing Systems (TPS)
- Decision Support Systems (DSS)
- Expert Information Systems (EIS)
- Management Information Systems (MIS
- Office Automation Systems (OAS)
Transaction Processing System
A transaction processing system (tps) collects, stores, modifies and retrieves the transactions of an organization. Examples of such systems are automatic telling machines (ATMs), electronic funds transfer at point of sale (EFTPOS – also referred to as POS). There are two types of transaction of processing:
- Batch processing: where all of the transactions are collected and processed as one group or batch at a later stage.
- Real-time processing: where the transaction is processed immediately
Decision Support Systems
Decision Support Systems are created to help people make decisions by providing access to information and analysis tools. many stockbrokers now use programs that will automatically put in requests to sell shares once they reach a certain price (either high or low). A DSS creates a mathematical model of the system which helps decison making about actions affecting a person organisation. Another example of a decision support system is the simple analysis tools that banks use to help formulate loans for prospective customers. A DSS allows the users to pose what-if questions and by changing a number of variables and then find out what the outcomes would be. In the home loan DSS customers can analyse how paying off more each pay would affect their loans, how a different type of loan may make it easier to make ends meet and by so doing tailor the loan to suit the customer.
A DSS depends upon the accuracy of the maths involved in creating the model and the ability of the user to accurately interpret the resulting data.
Example
Computer-driven trade has significantly affected the stock exchange. The Australian stock exchange uses a system called SEATS (Stock Exchange Automated Trading System). Computer and telecommunications technology, besides opening a wide market in over the counter dealings, has also given rise to trading on an international level. Personal computers and modems allow trading to occur around the clock, and the securities trading on one major stock exchange can now significantly affect the trading on others.
Expert Systems
Expert systems help to guide users to find solutions to problems that would otherwise need expert advice. They are useful in diagnosing, monitoring, selecting, designing, predicting and training. An expert system will ask the user to answer series of questions after which it will provide a suggested course of action. Expert systems will not take over but requires the user to make the final decision. Expert systems will advise. Some examples of expert systems are programs which help Doctors to diagnose a patient. In fact there are some web sites that will even diagnose patients. Another example of an expert system might be a program where a person puts in all of the vital statistics and then the program helps to advise about a fitness program which that person can then follow.
Management Information Systems
Management Information Systems provide information to managers of an organisation. This relates to reports, statistics, stock inventories, payroll details, budgets or any other details that assist managers with running an organisation. An EIS, executive Information System is a form of MIS designed for upper management and provides information which might help them make decisions ona strategic level about future directions or issues concerning managers.
MIS and EIS are really specialist examples of Decision Support Systems (DSS)
Office Automation Systems
Office Automation Systems are software packages such as MS Office which include word processors, spreadsheets, databases, presentation software, email, internet, desktop publishing programs and project management software. In office automation much work is processed electronically with the aim of saving space, being more efficient, and reducing paper usage. In reality, since office automation began in the mid 1980s, paper usage has soared as more people demand hard copies purely because they are easier to produce. Also as a function of the ease with which documents are produced compared to type writers higher standards of presentation are now expected.
