Management Information Systems Charles Parker 2nd Edition Chapter 3: System & Models Prepared By: Hamad Raza (Lecturer GCUF)

Systems A system is made up of a number of parts combined in a particular way to do something useful. We think of the combined parts as a single thing and we give it a name. Wheels, axles, pedals, gears, chain, seat and handlebars are combined to form a single whole we call a bicycle. A bike is a system when all the parts are connected correctly because it allows the rider to move from one place to another more easily.

Systems A system is a set of integrated elements that collectively work together to achieve some common purpose or goal. For Example: A football games is played according to the system that is composed of such elements as teams, stadiums, equipment, referees and rules. A CBIS is a collection of people, hardware, software, data & procedures that interact to provide timely data and information, both internally and externally to authorized people who need it.

Components of a System A system component / element can be tangible object such as a car or a person, an abstract concept such as data or information, or an event such as March 23 or “groundbreaking ceremony”. Tangible objects of course are those objects that we can touch or measure. Abstract concepts & events are intangible.

Components of a System When classifying systems, we frequently differentiate between a system’s logical description & physical description. Logical description of a system is a representation that specifies essential system elements in broad, often abstract terms. A physical description of the same system would be much more precise about how it is actually implemented.

System Environment All systems function within some sort of environment. The environment, like the system, is a collection of elements. These elements surround the system and often interact with it. Systems are normally delimited by a boundary, which separates them from their environment. Anything within the boundary is part of the system; Anything outside is a part of the environment.

Open Versus Closed Systems Systems are often classified as open or closed. A closed system is self-contained and does not interact or make exchanges across its boundaries with its environment. In other words, a closed system is one that has no interaction with any element not contained in it. An open system is one that interacts and makes exchanges with its environment. Most of the systems that occur naturally in business are open systems, and they interact with such environmental elements as consumers, suppliers, competitors, government and foreign countries.

Systems Models When studying system, it is often convenient to represent them in the form of a model. What is a Model? A Presentation of a real world elements and the relationship among them. For Example: 777 is a physical model of plane. The equation “Area = Length * Width” is a math model for calculating the internal area of rectangle. Porter’s five forces Model, Management level’s Model etc. Why we need Models The field of MIS uses many Models. Because management information system are often complex, it help to have a few models that simplify and clarify them.

General Versus Specific Models Models can be classified in many ways. One way concerns how general or specific the models are: General models are models that can be applied to wide variety of settings. Specific models are those that apply to a specific situation. For Example: Many of the graphical models Like Management Hierarchy Chart is a general model that can represent virtually any type of organization.

Types of Models Models can be classified in several other ways. These are: Graphical Models are models generally use such symbols as icons, boxes and lines to represent real-world elements and the relationships among them.

Types of Models Graphical Models (Cont.) Data flow diagrams (DFD) are widely used by systems analysts to graphically illustrate information systems. These graphical models show how data or information move from one process to another in an organizational system. These are useful for showing how systems work and are often used by systems analysts both to design systems & to clarify to users, programmers and other system analysts how components of a system fit together.

Types of Models Graphical Models (Cont.) Data flow diagrams (DFD)

Types of Models Mathematical Models A mathematical model is used to express quantifiable phenomena in mathematical terms. Q = economic order quantity of specific product D = annual usage of the product S = the cost of placing an individual order P = Price for the product H = Unit cost of carrying items in inventory

Types of Models Narrative Models A Narrative models describes system without trying to illustrate it in a formula or graph. For Example: A written description of a worker’s job duties. Physical Models A physical model is usually a three-dimensional representation that can be held or touched. For Example: System prototype is a physical model. A prototype is a small “pilot” model of a hardware or software system that is used to guide the systems analyst in building a larger system.

Who is responsible for Developing Models? Graphical & Narrative models of CBIS are usually constructed by system analysts. Whereas Mathematical models are commonly created by the operations research or management science staff, who are specially trained in building mathematical models.