Topic 3: Information System

Information Systems are sets of elements or components such as inputs, processing mechanism, outputs and feedback. A computer-based information system is software-based solution that is used to gather and analyse information.

There are five (5) types of Computer-based Information System, those are:

1.       Transaction Processing System- is an information processing system for business transactions involving the collection, modification and retrieval of all transaction data. Characteristics of a TPS include performance, reliability and consistency.

 2.       Decision Support System- an interactive computerized system that gathers and presents data from a    wide range of sources, typically for business purposes. DSS applications are systems and subsystems that    help people make decisions based on data that is culled from a wide range of sources.

3.       Expert System- a computer program that simulates the judgement and behaviour of a human or an organization that has expert knowledge and experience in a particular field.

4.       Management Information System-is a general term for the computer systems in an enterprise that provide information about its business operations. It's also used to refer to the people who manage these systems. Typically, in a large corporation, "MIS" or the "MIS department" refers to a central or centrally-coordinated system of computer expertise and management, often including mainframe systems but also including by extension the corporation's entire network of computer resources.

5.       Executive Support System- is software that allows users to transform enterprise data into quickly accessible and executive-level reports, such as those used by billing, accounting and staffing departments. An ESS enhances decision making for executives.

    Components of CBIS

     ü  Procedure

     ü  Telecommunication

     ü  Database

     ü  Software

     ü  Hardware

     ü  People

Information System Development Methodologies

      What is an Information System Development?

-          is the process of defining, designing, testing, and implementing a new software application or program.

A methodology is a collection of tools, procedures and documentation aids which helps the system         developers to implement a new information system. The system development can be initiated when there       is a problem existing in the system and when the organization wants to produce a new information                 system.

   The participants in system development are as follows:

1             Project Manager

2                   Stakeholders

3                   Users

4                   Programmer

5                   System Analyst

                    Support Personnel

       There are steps in Information System Development Planning:

Strategic Plan

Develop Objectives

Identify IS project

Analyse resource

Set schedule and deadlines

Develop IS

Methodology

          -is a combination of procedures, techniques (methods) and tools for developing a system.

      Elements of Methodology

      Procedures: the sequence or the well-defined steps

      Methods: technical for building software/program/system

     Tools: provide automated/semi-automated support for process and techniques/methods

     Characters of Information System Development Methodologies

-                   Work breakdown structure that provides guidance on what to do and when to do.

-                   Techniques on how to do and what needs to be done.

     The importance of Methodology in an organization:

1.       Ensure system development process is systematic

2.       Allows system development to be managed to ensure high quality assurance

3.       To achieve effectiveness and efficiency in organization

4.        To meet user requirement

      Types of Methodologies

1.                  Structured Approach (SDLC)- it is a comprehensive method that covers activities such as understanding       why the system should be built, studying the project feasibility, analysing problems, choosing the system         design and architecture, implementing and testing it, up to delivering the system as product to the users. It       is characterized by a chronological approach and the users get to see the system late in the development.

2.                   Prototyping- is a system development methodology that uses a trial-and-error approach for discovering          how a system should operate. Its main aim is to enhance the quality of the requirement specification. It is        useful when the desired system needs to have a lot of interaction with the end users.

        Gane and Sarsons (STRADIS)- it focuses on the Data Flow diagram, which is used to describe the              processes of the system, and how the processes transform data.