IS312: information systems theory and applications

LECTURE 1:SYSTEMS THEORY AND MAIN CONCEPTS

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Outlines• What is a system?• Information systems definition.• System Elements (Components).• System Concepts

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Definition - Example

GlassSteel

RubberPlasticCopper

aluminum

CAR

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A system could be defined as: “A set of interrelated components, with a

clearly defined boundary, working together to achieve a common set of objectives by accepting inputs and producing outputs in an organized transformation process.”

“An organised assembly of components with special relationships between the components.”

What is a System?

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What is a System? The system does something, i.e. it exhibits a type of

behavior unique to the system or has a specific objective or purpose.

Each component contributes specifically towards the behavior of the system and is affected by being in the system. If a component is removed, it will change the system behavior.

Examples:1. The biological system of the human body.2. The Electrical system of your house.

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Information systems (IS) Definition

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A combination of hardware, software, infrastructure and trained personnel organized to facilitate planning,  controlling, coordinating and decision making in an organization.

A system that gathers and transforms data in order to produce information for its end_users.

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Information System Resources

InformationSystem Resources

People

Hardware

NetworksSoftware

Data

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Recognizing Information Systems• Business professionals should be able to look

at an information system and identify… The people, hardware, software, data, and network

resources they use. The type of information products they produce. The way they perform input, processing, output,

storage, and control activities.

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System Elements

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INPUTS OUTPUTS

BOUNDARY

TRANSFORMATIONPROCESS

The basic elements of a system

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Environment and Boundary

A boundary: what is inside the boundary belongs to the system, everything outside the boundary is not part of the system. Systems, or their components, inter-act with the world outside their boundary.

The system’s Environment: The part of the outside world with which the system interacts.

System Elements

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System Elements

Inputs, Transformation Process and OutputsThe interactions of a system with its environment can take the form of inputs or outputs. Inputs take the form of material objects, energy and/or information flowing from the environment into the system. Outputs are released or sent from the system back into its environment. This output can either be useful or waste. Within the system, the inputs usually undergo some specific Transformation process at the system boundary, so that the outputs are different from the inputs. The system components responsible for these transformations are called the Interfaces.

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Basic Functions of a System

Input

Capturing and assembling

elements that enter the

system to be processed

(Ex: raw materials,Data, students…)

Processing

Transforma-tion process

converts input into output

(Ex: manufacturing process, Breathing

process…)

Output

Transferring transformed elements to

their ultimate destination

(Ex: finished product, human

services…)

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System Elements

Components and Subsystems

A system consists of various Components which, taken together, make up the system.

The interaction between the system components is responsible for processing the inputs into outputs. Although components can also interact directly with elements from the environment across the system boundary, most of their interactions will be with other components within the same system.

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System Elements

Components themselves can be viewed as smaller systems on their own: they are Subsystems of the system under consideration. The motor car, for instance, has an electrical sub-system and an air-conditioning sub-system.

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System Elements

Components and Subsystems

In the case of an information system, the basic components that interact are:-

The hardware or physical equipment used to process and store data. The software and procedures used to transform and extract information. The data that represents the activities of the business. The network that permits the sharing of resources between computers. The people who develop, maintain and use the system.

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System Elements Objectives, Control

Systems have a function, goal or purpose. This goal can be internalized e.g. the desired room temperature for a central heating thermostat device or the profit motive in a commercial business enterprise. This goal can also be imposed from the outside e.g. when we use a motor car to drive from our home to the shop.

In order for the system to achieve its goal(s), it needs to be able to modify its behavior. Control is the mechanism whereby special control signals or, control inputs coming from outside the system, modify the processes and activities which occur within the system.

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System Elements

Objectives, Control

The Controller is the component or (sub-)system which exercises the control and can be part of or outside the system under consideration. The controller observes the behavior of the system, typically by comparing certain system outputs to the desired state or objective.

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Systems Concepts

Open vs Closed system(Greater degree with the environments vs. self sufficient (independent))

Open system : a system that interacts with its environment.

There is in reality no such thing as a closed system, which would have no inputs or outputs and therefore, in a sense, no environment.

Some systems are mainly self-sufficient while other, more open systems have a much greater degree of interaction with their environment. Information Systems

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Systems Concepts

Dynamic vs Static

(the more dynamic the system more flexibility between components function in different ways as activities change).

A dynamic system: is a system that has at least one (and usually many) activity or process. A static system: has no activity, whatsoever.

There are very few completely static systems.

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Systems Concepts

Continuous vs Discrete A continuous system is a system where inputs (and outputs) can be varied by extremely small amounts or quantities.

A traffic light (robot) is a discrete traffic signaling system because its three lights (green, amber or red) are either on or off.

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Systems Concepts

Continuous vs Discrete

Discrete systems are systems where the inputs or outputs can take on only certain discrete or distinct values.

A mercury-based thermometer, is a continuous system as the level of mercury rises or falls gradually along with imperceptible fluctuations in the environment’s temperature.

Many electronic systems are a combination of both e.g. a digital thermometer has a sensor that records temperature as a continuous input but displays a temperature reading which has been rounded to the nearest degree.

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Systems Concepts

Structure and Hierarchy The interactions between the various sub-systems

and components of a system display some pattern or regularity. In this sense the observer can identify certain relationships, which contribute to the overall behavior of the system. The entire set of relationships is referred to as the structure of the system.

Structure:The physical or symbolic arrangement of the elements

of a system refers to the formalized hierarchy or responsibilities and roles of the individuals therein and can also refer to the geographic distribution of inanimate elements at any given time.

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Systems Concepts

Structure and Hierarchy System hierarchy o System within system within system

o Subsystem Any component or element that belongs to a system that has a level lower than that of the system itself, for example, an organelle is a subsystem of a cell.

o Suprasystem The system that has a level just higher than a given system. e.g. physical universe (galaxies -> solar

system -> planets -> Earth -> all livings -> etc.)

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Questions ..

Thank you for listening

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To understand faster!!!

Please Read Section IV: IS Management of Book(1) Discovering Information systems, Page No. from 120 to 133 for further reading.

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“A good system shortens the road

to the goal.”

Orison Marden