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Information SystemsCS-507

Lecture 08

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A system is a group of elements that areintegrated with the common purpose ofachieving an objective.

Examples

Purchases System

Sales System

What are Systems?

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Input Elements:Raw data input to the computer system

Processing:

Computation, analysis

Output Elements:

Results of computation or analysis

Components of a System

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Control mechanism:Comparison of actual with expected

Feedback system:

Corrective action

Objectives:

Expected / Ideal output

Components of a System

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Open loop system

Closed loop system

Open system

Closed system

Types of System

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Systems

Every system that is constructed isexpected to generate some sort of outputbased upon the information fed into it.

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Systems

The output is expected to be used to

Evaluate system performance whetherthe output complies with stated objectives

of the system Generate instructions for changes and

improvements

Either in the output, or

In the plans, or

In the objectives

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Types of System

Examples.

Book Store

open system any and everyone is allowed to

view and purchase the books available. School Library

Closed system entry to the library is restrictedto the students only.

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Types of System

In an open system we refer to the connectionit has to its environment by means ofinflows and outflows of resources between

the environment and organization.

A closed system is a system that isdependant on internal resources and data fordecision making rather than externalenvironment.

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Types of System

THE BOOK STORE may have:

An Open loop if customer feedback isnot taken for the purchase of books for the

store

OR

A Closed loop if Customer

feedback/interest is taken into accountwhen selecting the books to be purchasedand displayed in the store.

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Types of System

The SCHOOL LIBRARY may have:

An Open loopif students feedback isnot taken for the kind of books to be

stocked in the library.

OR

A Closed loop if students interest is the

determinant criteria for the kind of booksthat are to be carried out in the library.

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Open Loop System

Business decisions made by management havean impact on the marketplace, and the impact ofthat decision is measured only indirectly by thecompany's computer systems.

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Open Loop System

By measuring the response within the open-loop architecture, the marketplace response isquantified.

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Open Loop System

The impact of the corporate decision is feltindirectly through the reactions of themarketplace and is measured indirectly by thecomputer systems that are used by the

company.

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Open Loop System

Such interactions between the decision processand the measurement of the effectiveness of thedecisions made can be called an open-loop

decision environment.

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Open Loop System

There may be factors other than thedecision made by corporate managementaffecting the results achieved in the

marketplace.

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Feedback is an integral part of the closedloop system.

The corrective action as a response to theoutput requires two other components

Control Mechanism Variance Analysis

Objectives Predefined expected output from

the system

Closed Loop System

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Closed Loop is a system where part of theoutput is fed back to the system to initiatecontrol to change

either the activities of the system, or

input of the system

Closed Loop System

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Closed Loop System

In a closed-loop decision environment, theimpact of decisions can be measured veryprecisely.

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Closed Loop System

In a closed-loop decision environment,management takes a decision, the computersystem singles out exactly to whom the decisionapplies and a direct action is taken as a result of

that decision. The response to the action canthen be measured on a case-by-case basis. Theresults of the management decision can bemeasured quickly and directly.

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Closed Loop System

With a closed-loop decision environment,there is the possibility of having very quickand very accurate feedback on the

decision process. The ability to make thisassessment is very valuable.

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Information Systems

CS-507Lecture 08