LECTURE 2: DR. DE-GRAFT JOHNSON AMENUVEVE DEI

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1 LECTURE 2: DR. DE-GRAFT JOHNSON AMENUVEVE DEI College of Education School of Information and Communication Department of Information 2018/2019 ACADEMIC YEAR

2 Systems Introduction Elements of a system Types of systems Information Systems Introduction Types Slide 2

3 SYSTEM CONCEPTS A system is a set of interacting or interdependent components forming an integrated whole or a set of elements (often called' components ) and relationships which are different from relationships of the set or its elements to other elements or sets. They are linked together according to a plan to achieve a specific goal". System can be defined as a set of elements joined together for a common objective. A group of interrelated or interacting elements forming a unified whole e.g., business organization as systems. A group of interrelated components working together towards a common goal by accepting input and producing output in an organized transformation process. Slide 3

5 Elements of Systems Inputs Outputs Processing or transformation Monitoring & Control Environment/surroundings Feedback Boundaries and interface Relationship Slide 5

6 Input: It involves capturing and assembling elements that enter the system to be processed. The inputs are said to be fed to the systems in order to get the output. For example, input of a 'computer system' is input unit consisting of various input devices like keyboard, mouse, joystick etc. Slide 6

7 Output: Those elements that exists in the system due to the processing of the inputs is known as output. A major objective of a system is to produce output that has value to its user. The output of the system maybe in the form of cash, information, knowledge, reports, documents etc. the system is defined as output is required from it. It is the anticipatory recognition of output that helps in defining the input of the system. For example, output of a 'computer system' is output unit consisting of various output devices like screen and printer etc. Slide 7

8 Process: The processor is the element of a system that involves the actual transformation of input into output. It is the operational component of a system. For example, processor of a 'computer system' is central processing unit that further consists of arithmetic and logic unit (ALU), control unit and memory unit etc. Slide 8

9 Control: The control element guides the system. It is the decision-making sub-system that controls the pattern of activities governing input, processing and output. It also keeps the system within the boundary set. For example, control in a 'computer system' is maintained by the control unit that controls and coordinates various units by means of passing different signals through wires. Slide 9

10 Feedback: Control in a dynamic system is achieved by feedback. Feedback measures output against a standard input in some form of cybernetic procedure that includes communication and control. The positive feedback motivates the system. The negative indicates need of an action. The feedback is a reactive form of control. Outputs from the process of the system are fed back to the control mechanism. Slide 10

11 Boundary and Interface: A system should be defined by its boundaries-the limits that identify its components, processes and interrelationships when it interfaces with another system. For example, in a 'computer system' there is boundary for number of bits, the memory size etc. that is responsible for different levels of accuracy on different machines. The interface in a 'computer system' may be CUI (Character User Interface) or GUI (Graphical User Interface). Slide 11

12 Environment: The environment is the 'super system' within which an organization operates. It excludes input, processes and outputs. It is the source of external elements that impinge on the system. For example, if the results calculated/the output generated by the 'computer system' are to be used for decisionmaking purposes in the factory, in a business concern, in an organization, in a school, in a college or in a government office then the system is same but its environment is different. Slide 12

13 Types of Systems Systems are classified in different ways: Physical Systems Abstract systems. Open System Closed systems. Computer-based information systems. Slide 13

14 Physical: They're tangible entities that may be static or dynamic in nature. These are the concrete operational systems made up of people, material, machines energy & other physical things. Can display activities or behavior. Abstract/Conceptual They re conceptual or non-physical. The abstract is conceptualization of physical situations. This system is an orderly arrangement of independent ideas. For example: tacit knowledge, ideas Slide 14

15 Open System It interacts with the environment in which it exists. It exchanges inputs and outputs with the environment. Such regular interaction with the environment makes the study of open systems difficult. For example: the library, information center, records center, computer, museum Closed System It does not interact with the environment in which it exists. It is in a state of isolation. It is completely self-contained. This is only of theoretical interest as in reality systems exhibit different degrees of openness. It has only controlled & well defined input & output. For example: Television is itself is closed system which controls its sharpness, brightness automatically with sensors. Slide 15

16 Subsystem A subsystem is a set of elements, which is a system itself, and a component of a larger system. Sub systems are the smaller systems within a system. Each system is part of a large system. The business firm is viewed as the system or total system when focus is on production, distribution of goal and sources of profit and income. The total system consists of all the objects, attributes and relationship necessary to accomplish an objective given a number of constraints. Eg. cataloging department, collection unit, reference section of a library Slide 16

17 INFORMATION SYSTEMS (Overview) The combinations of hardware, software, and telecommunications networks that people build and use to collect, create, and distribute useful data, typically in organizational settings. Interrelated components working together to collect, process, store, and disseminate information to support decision making, coordination, control, analysis, and visualization in an organization. A set of interrelated components that collect (or retrieve) process, store and distribute information to support decision making and control in an organization. In addition to supporting decision making, coordination and control, information systems may also help managers and workers analyze problems, visualize complex subjects and create new products. Slide 17

18 Types of Information System Informal, Formal: Manual or Computer based Slide 18

19 Informal Information System It represents the evolving and complex patterns of human behavior. Never formalized by the organization, but is often vital to the effectiveness of communication within the organization and hence the effectiveness of the organization itself. It exist within an organization (interpersonal networking, water cooler gossip, etc.) It is an employee based system designed to meet personnel and vocational needs and to help solve work related problems. Slide 19

20 Formal information systems They are structured; that is, they operate in conformity with predefined rules that are relatively fixed and not easily changed. They rely on procedures (established and accepted by organizational practice) for collecting, storing, manipulating, and accessing data in order to obtain information. They do not have to be computerized, but today they usually are. Formal information systems could be Manual (man-made or human-based information system Computer based information systems Slide 20

21 Manual Information System This is a class of information system comprising formalized noncomputerized procedures for the production of information within an organization. Historically, prior to computers, all organizational information systems operated in this way, with clerks processing the information. It is important when introducing technology to ensure that the development costs are balanced by business advantage/productivity gains - the company investment in specialist staff skills cannot always be replicated in a computerized system. Eg include the card catalog, indexes, yearbook, dictionaries, encyclopedia, almanac, Textbooks, Magazine articles, Book reviews, Handbooks, Statistics, Chronologies; Directories; Fact books; Guidebooks; abstracts, bibliographies; Manuals. Slide 21

22 Computer-Based Information System (CBIS) makes use of information technology Its an organized integration of hardware and software technologies and human elements designed to produce timely, integrated, accurate and useful information for decision making purposes uses computer technology to perform some or all of its intended tasks. Such a system can include as little as a personal computer and software. Or it may include several thousand computers of various sizes with hundreds of printers, plotters, and other devices, as well as communication networks (wire-line and wireless) and databases. Slide 22

23 Components of Information Systems (CBIS) 1. Resources of people: end users and IS specialists, system analyst, programmers, data administrators etc.. 2. Hardware: Physical computer equipment and associate device. 3. Software: programs and procedures. 4. Networks/Telecommunications: communications media and network support. 5. Data/Database: data and knowledge bases 6. Procedures/Protocol Slide 23

24 Slide 24

25 Functions of Information Systems All information systems carry out a series of functions that may be classified as follows: Data capture and collection. Storage. Information processing. Distribution or dissemination of information. Slide 25

STRUCTURED SYSTEM ANALYSIS AND DESIGN. System Concept and Environment

STRUCTURED SYSTEM ANALYSIS AND DESIGN Definition: - System Concept and Environment A system is an orderly grouping of independent components linked together according to plan to achieve a specific objective.