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The word 'system' is widely used. It has become fashionable to attach the word 'system' to add a contemporary flair when referring to things or processes. People speak of exercise systems, investment systems, delivery systems and information systems. In terms of computer, in this section, we will discuss general system's concepts of analyzing and designing information systems.
The word 'system' is derived from the Greek word system, which means an organized relationship among the functioning units or components. In our daily life, we come into contact with transposition of a system, the communication system, the accounting system, the production system, the economic system and the computer system for over three decades. We are more concerned with computer systems.
A system can be categorized into the following groups.
The physical system is tangible entities that may be static or dynamic, e.g. building whereas the abstract system is conceptual entity, e.g. company.
An open system is a system which continuously interacts with its environment. The interaction can take the form of information, energy or material transfers into or out of the system boundary, depending on the discipline which defines the concept. An open system should be contrasted with the concept of an isolated system which exchanges neither energy, matter nor information with its environment.
A closed system refers to software in which the specifications and detail of implementation (typically source code) are kept secret, as opposed to open source system.
A deterministic system is a conceptual model of the philosophical doctrine of determinism, applied to a system for understanding everything that has and will occur in the system, based on the physical outcomes of causality. In a deterministic system, every action or cause, produces a reaction or effect and every reaction, in turn, becoming the cause of subsequent reactions.
A deterministic system has a single result or a set of results given a set of input parameters, while a probabilistic system will have results that vary. Often, a probabilistic system (also called stochastic model, process or system) is solved with the Monte-Carlo method. In this case, a computer program uses a pseudo-random number generator to provide values of the attributes in the system, which may vary.
The program provides an assessment of the uncertainty of results. Typically, a large number of runs (also called trials or iterations) are made. Summary statistics may include the value that occurs most frequently (mode), the mean value, and low and high range, for instance, the 10% and 90% percentile. The standard deviation and histogram of results may also be part of the summary information. There is no single standard presentation as this will depend on the application.
The alternative Monte-Carlo methods are to solve the problems using the mathematics of probability. This can be very complicated to do in some cases. Monte-Carlo method is available in Excel as functions. For example, and between () for uniform discrete distribution and rand () for uniform continuous distribution from 0.
The systems developed and engineered by human are a man-made system. In this section, we are more concerned about man-made information systems, which are further classified as:
This system defines very clearly about the workflow system, communication flow-down, and the authority. The information flows in terms of policies, goals, strategies, rules and regulations from the top level management to the bottom level of management. The information also flows from the bottom level management to the top level in terms of feedback, results of work done, etc.
The informal information system should be employee based and cater to their development and solve their work related problem. Employee co-operation and the knowledge of the informal communication should help one to get good informal information systems in place.
The third category of an information system depends mainly on the computer for handling business applications. System analysts develop several different types of information system to meet a variety of business needs. There is a class of systems collectively known as Computer Based Information Systems.
As we have different types of transportation system such as highway systems, railway systems, and airline systems; computer-based information systems are also of too many types. They are classified as:
Every system except the super system is a part of larger system. The super system contains all the other systems. Since every system is a part of larger system, it is also a subsystem of the larger system. For example, a sales department is a sub-system of an organization. In larger systems, each sub-system is interlinked and forms closed deterministic system.
The system study may be defined as a study of the operations of a set of connected elements and of the interconnections between these elements. It is a step-by-step process used to identify and then develop specific improvements in an organization's information system. It shows clearly that one cannot ignore any part or element of a system without first finding out the effect that element has on the operation of the system as a whole.
System is a collection or arrangement of entities or things, related or connected in such a way that they form a unity on the whole. In system, the entities are designed and controlled by people, the entities are generally arranged so that they interact to accomplish one or more objectives. For example, the entities of an educational system consist of students, faculty, administrators, textbooks, buildings, equipment and many other entities. The entities of the system interact (e.g. faculty teach students, students read textbooks, administrators schedule classroom facilities), and ultimately, the primary objective of the system, learning is accomplished. Anything external to the system is referred to as the environment of the system.
In any system, a number of entities are interrelated. The following transformation process exemplifies the interwoven relationships among many entities. The total transformation system is built up from these entities.
Let us see another example of an educational system. In any educational system, the students enrolled have particular characteristics. They learn in the institution or they remain an Educational System for a certain period and finally, a new type of student emerges. The student possesses new characteristics. During the study period in an Educational system , the students are linked with many entities such as faculties, textbooks, administrators, building, equipment, etc. The following diagrammatic representation table shows the overall structure of an Educational System.
The system discussed above can be classified into two categories. They are:
Khanal, R.C. Khanal, R.C. Computer Concept for XII. Pashupatigriha Marga, Thapathali, Kathmandu, Nepal: Ekta Books Distributors Pvt. Ltd., 2010. 9-13.
Adhikari,Deepak Kumar.,et.al., Computer Science XII,Asia Publication Pvt.Ltd
System can be categorized into following: