SYSTEM ENGINEERING ((((SSADSSADSSAD) ))) - Ajay … · · 2011-04-04B. H. GardiCollege of Engineering & Technology, RAJKOT Department of Master of Computer Application Prepared

B. H. Gardi College of Engineering & Technology, RAJKOTDepartment of Master of Computer Application

Prepared By : Ajay A. Ardeshana Email : [email protected]

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Prepared By :-

Mr. Ajay A. ArdeshanaMCA LecturerAt GARDI VIDYAPITHRAJKOT.Email :- [email protected] :- + 91 – 95588 20298

Prepared By: Ajay A. Ardeshana Email: ajay.240219 [email protected] Mobile: 9558820298 27 February 2011

SYSTEM SYSTEM SYSTEM SYSTEM

ENGINEERINGENGINEERINGENGINEERINGENGINEERING

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Chap5er - 6



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System Concepts

� System provide a meaningful framework for describing andunderstanding the features and functions of the subjects.

� Definition :-� System is defined as a set of elements in an orderly manner toaccomplish an objective.

� System is a set of elements that are together to perform thefunctionalities or set of task for particular subject.

� A system is not a randomly arranged set. It is arranged withsome logic governed by rules , regulations , principles andpolicies .


� Examples of System :-

Systems Elements Objectives

Computer Input, Process and Output Devices.Operating Systems, Compilers, Packages.

Process the data and provide the information.

Accounting Financial Transactions, Accounting Principles and Rules, Transaction Processing Method of Accounting

Process the transaction and produce the monthly books of accounts and the information for financial management.

Business Organization

People, Plant and Machinery, Product and services, Communications, Transport, Materials.

Produce goods and services to achieve the business objectives of services, turnover and profits.



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� For Example :-� If a computer system is designed to perform a commercial data processing,then the elements will be a data entry devices, a CPU, a disk, a memory, anapplication programs and a printer.

� Any system has three basic parts, which are organized in orderlymanner. These three parts can be represented as :

� System may have single input and multiple outputs or may haveseveral inputs and outputs.

� If additional objective is to be introduced in the system, it may bepossible as the new objective may fall outside the boundaries or thescope of the system.

� For example a computer designed for processing the commercialdata can not achieve the objectives of design and drafting.

Input Process Output


� The environment influences the choice of inputs, the method ofprocessing, and the nature and the content of the outputs.

� Since the systems are design for specific objectives/outputs, thedesigner provides a filter around the system to control the influenceon the system.

� For example take the manufacture system, where the objective is toproduced products of desired quality. Since the row material and thedesign processes are selected with the objective, the quality controlsystems exercise a control on a quality of row material and keep acontinuous watch on process parameter to keep the desire quality.


Filter

Environment



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System Control

Comparison Unit

Control System Model


Sensor

Standard

Corrective Unit

Channels

Of Feedback


� Since the systems are design to achieve the specific objectives, ensuring theachievement of an objective, becomes an integral part of a system.

� The control calls the measurement of an output in some terms.� Sensor :-

� The that measures the output is called a Sensor.

� Sensor measure the output and compare it with the standards.

� If the measure output compares well with the standards, the system providethe feedback to continue the operation.

� Comparison Unit :-� If the measure output compares well with the standards, the system providethe feedback to continue the operation.

� If the measured output does not compare well with the standard, then thefeedback provides to the system to stop the operation.

� The process of comparison of a measured output with the standard is done bya unit called Comparison Unit.

� Feedback Mechanism :-� The mechanism, which provides a signal to the system, about the quality ofperformance, is called a Feedback Mechanism.



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� Corrective Unit :-� Many a ties system may not have an appropriate mechanism to act on thesignal which it receive. It is, therefore, necessary to provide an in-builtmechanism, which will decide based on the feedback to stop, regulate orcontinue the system operations.

� Such a mechanism is called a Corrective Unit and is responsible for ensuringthe system performance.

� The process of measuring the output, comparing with the standard, sending thesignal to the corrective unit an the corrective unit active upon it, is called acontrol .

� The concept of control is based on the condition of feedback .� If the feedback is positive means the measure of the output comparesfavorably with the standards or norm, the control will keep the systemoperating in the same condition.

� If the feedback is negative means the measure of output is unfavorablewhen compare to the standard or norms, the control will act on the input orprocess back to bring back the system to the state of equilibrium.


� the concept of the control system model is applied to data processingwhere all the features are used in the programs of the dataprocessing.

Input DataUse of Program for Processing

Computed Result

Summary of Result

Compare Result V/s Target

Decision Control

Feedback Positive or Negative

Target Results

Change the Program if Necessary

Control System Model for Data Processing



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Action to correct the Process of Manufacturing

Feedback Through Plotting of Weights

MIS Model of Quality Assurance

Weight

One Measure of Quality

Quality Assurance Manager

Corrective Unit

RowMaterial

Data on Measures of Quality

Manufacturing Process

Analysis of Quality Data

Weight, Size, Color, Quality

Designated Measures of Quality

Weight Control Chart

Tools to Compare

Upper & Lower Limits

Quality Control Limits


Types of System

� A system is an arrangement of smaller systems in a logical order. When manysmaller system together make a large system the smaller systems are calleda subsystems of a large system.

� A large system can be split or decomposed into smaller subsystems up to acertain levels. Decomposition of a system into subsystems can be in aserial form or it could be in matrix from .

� In serial system processing the output of one subsystem is the input of nextsubsystem and so on.

Subsystem1

Manufacturing

Subsystem2

Quality Control

Subsystem3

Marketing

Subsystem in Serial Order



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� We say that the process is transparent to us when we are ableto understand the system. But if the process of inputtransformation is not visible and understandable then we saythat the system is a Black Box System and the process is nottransparent.

Subsystem1

Manufacturing

Subsystem2

Marketing

Subsystem3

Quality Control

Subsystem4

Accounting

Subsystem operating in Matrix Order

� In matrix arrangement thedifferent outputs goes tothe different subsystems.

Inputs Outputs

Black Box System


� Breaking the system in a hierarchical manner provide a way tostructured system analysis. It gives a clear understanding of thecontribution of each subsystem in terms of data flow and decisions andits interface to the other subsystem.

Hierarchical Structure of the System



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� The system can be classified based on the predictability of its output andthe degree of information exchange with the environment.

� A system is called Deterministic when the inputs, the process and theoutputs are known with certainty. (e.g. Accounting System)

� A system is called Probabilistic when the output can only be predictedin probabilistic terms. (e.g. Demand Forecasting)

� If a system is functioning in isolation from the environment, then thesystem does not have any exchange with the environment nor it isaffected by the environment changes. Such a system is called a ClosedSystem . Most of the systems based on the rules and principles areclosed system.

� If the system has exchange with the environment and is affected by theenvironment changes is called Open System . The systems which arerequired to respond to changes in the environment, such as Marketing,Communication and forecasting are Open System.


Handling System Complexity

� Information is relatively complex compare to the physicalsystem, and therefore they should be handle properly.

� To handle the complexity, the system can be viewed as anassembly of subsystems each with the clear definition ofboundary, interface and their connectivity. The subsystemsthen put in hierarchical order to provide a structural view.This process is called Factorization .

� Another method of handling the complexity is to resort tosimplification by clustering the subsystems together.



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�Handling all the subsystem together with theirinterconnection is difficult. Each interconnection actsas a channel for the input-output communication.

�The process of simplification provides a way tohandle this interconnection and reduce thecomplexity.

� The method of simplification is as follows :1. Identify the subsystems which have to be together for thefunctional.

2. Form a cluster of these subsystems and identify interconnectionbetween these clusters.

3. Form cluster of the remaining subsystems.

4. Connect the cluster with an interface.


� For Example :- Material Management System Divided into 7different subsystems as follows :

A. Procurement System.

B. Purchase Order Follow up system.

C. Receipt Accounting System.

D. Material Receipt Planning System.

E. Material Issue Requisition System.

F. Bill Passing and Payment System.

G. Inventory Control System.

B A

E C

G

D

F

Step-2 Subsystem with Interconnections



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� The subsystems can be clustered in number of ways. In theexample we have clustered the system I base on the managementfunctional such as purchase account and planning.

� The choice of the basis for clustering will be depend in the viewtaken by the designer of the system to handle the complexity.

B

A

F

C

E

D

G

Cluster 1Purchase Function

Cluster 2Stock

Accounting Function

Cluster 3Material Planning & Control Function

� When the subsystems are clustertogether and connected, thedesigner face the problem of tightconnectivity .

� The connectivity becomes tightbecause the close coordinationrequires among the clusters in termof time and resources.

� When the systems are of open type,the environmental changes causesa lot of behavioral influences.

Step-3 Formation of Clusters


� The solution to the problem of tight connectivity is to decouple the cluster fromeach other by providing the interface between the clusters.

� The problem of tight connectivity and providing interface arises from therequirement of heaving the input information from other subsystem on time.

� So basically it the problem of synchronized communication in the informationexchange between the two clusters.

� The use of decoupling mechanism should be considered as the last alternativefor reducing the rigid requirements of a communication exchange.

B

A

F

C

E

D

G

Purchase Information

Stock Information

Interface Interface

Step-4 Decoupling of subsystem’s clusters by stock information interface.



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System Efficiency and Effectiveness

� The performance of the system can be measured by twofactors : the Efficiency and the Effectiveness

� The efficiency indicate the manner in which the inputs areused by the system. Being efficient means the system useinputs in a ‘right’ way. If the input-output ration is adverse,we say that the system is inefficient.

� The effectiveness is the measure for deciding whether thesystem provides the desired output or not. Being effective,means producing the ‘right’ output in terms of quality andquantity.


Post Implementation Problem in the System

� When the systems are allowed to run for some time, theytend to become disorganized , resulting into a inefficiency.

� The process of disorganized and its causes are called‘Entropy ’. The designer is thus call upon to introduce anegative Entropy whereby the disorganization is arrestedand the system is brought back to the state of balance.

� The process of providing the negative entropy is called thesystem maintenance .

� The negative entropy is provided as a part of the systemroutine.



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� The steps for providing the negative entropy are as follows:a) A periodical review of the system.

b) User meeting to assess the current utility of the system and the level ofsatisfaction.

c) Subjecting the system to an audit check through the test data.

d) Running the system under audit trail.

e) Bringing out system modifications.

System Indication of Entropy Negative Entropy

Human Body Loss of Weight, Headache

Medical check-up and prescribed diet and medicines.

Computer System halts, read and write errors.

Preventive maintenance and replacement of subjective components.

Data Processing

Errors and omissions in the data on increase.

Review and introduction of streamlined procedures.


� The another problem that the system designer face is that the change in goal oforganization due to the environmental changes.

� If the system is enough capable to handle the change in goal, then the systemdisorganization is not required, but the system design is inflexible, then it is notpossible to handle the changes by the system and the system disorganization isrequired.

� Problem of system disorganization arise in the organization because thebusiness environment changes, leading to a modification in the business goaland objectives.

� Such a changes in the requirement forces the changes in the MIS goal, callingmodification to the information system to meet the revised information needs.

� The designer should keep in mind that the organization is an O penSystem bound to receive new input in an unplanned and unscheduled mannerand the organization should adapt itself.

� Keys to handle the post implementation problems :� Systemmust be comprehensive and flexible.

� Associated peripheral systems should be built with a flexible design.



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Classes of Systems

� The systems performs different roles through different processes to achieve asystem goal. Though at the core they satisfy all the attributes of the system,they differ in the nature due to the goal assigned to them.

� MIS is classified in five classes as under :

1. Data Processing System (DPS)

2. Transaction Processing System (TPS)

3. Application Processing System (APS)

4. Business Function Processing System (BPS)

5. Integrated Information Processing System (IPS)

� DPS is design to capture, collect or enter the data to process in certainspecified manner to achieve the following:

� Data is complete, correct and valid.� Such a data is processed and organized in some further processing.


� Data Processing System (DPS) :-

� DPS is design to capture, collect or enter the data to process in a certain specified manner to achieve the followings :

� Data is complete correct and valid from all aspects.

� Such a data then is processed and organized in some form for processing.

� DPS may have algorithm using one or more data inputs and may produce one or more outputs.

System of Capture, Collect, Enter

System of Security, Checking, Validating

System of Result Processing

Query Processing

Master Files

Results Record File(s)Display

Reports

Model of DPS



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� Transaction Processing System (TPS) :-

� TPS is design to handle the transaction between parties. A parties could be two or more heaving designated role in TPS.

� TPS use data file, master files and transaction records to execute transaction.

� Example of TPS is Payroll system.

Model of TPS

TPS for accuracy, completeness, consistency, validity and decision for acceptance or rejection

Master Files

Processed Transaction File(s)Records

Display

Reports or Documents

Transaction Data Files

Transaction Process Algorithm OutputQuery

Processing


� Application Processing System (APS) :-

� APS id built over DPS and TPS. APS use files created by DPS and TPS and applies application –processing rules to execute the application.

� APS may have an output as a documents, report or a set of results required further in Business Function System (BFS).

Model of APS

APS for :Verification, Checking, Selecting Rules, Computing Formulas and formatting.Master

Files

Application Output Filed and Records

Display

Reports or DocumentResults

ProcessedTransaction File(s)

Application Processing Rules ReportQuery

Processing



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� Business Function Processing System (BPS) :-

� BPS aids in business function processing and help management in decision-making required within the scope of business function.

� It brings out more MIS report for business function management such as Sales,Production, Materials, Customer Relation and so on.

Model of BPS

System Processing after checking file consistency and

validity.

Transaction Output File(s)


Display

Future MIS

Reports

Application Process system Output Files

System Processing Rules Query

Processing



� Integrated Information Processing System (IPS) :-

� IPS sits on the top of the rest of the system discussed so far namely DPS, TPS, APS,BPS. IPS draws its inputs from these systems, and applies information processing rulesto bring out an output.

� IPS generally meet the requirements of top management in the area of planning,budgeting and strategic control.

Model of BPS

Reports

Function Databases

and Management

APS Output File(s).

TPS Output Files.

Knowledge Database

IPS Rules, Models, Algorithms

Use of Information Process Tools

Result Database

Spread Sheet

Application

Executive Information System

Data Warehousing System

Data mining System

Knowledge Process System



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General Model of MIS

SOURCING SYSTEM

DATA PROCESSING

TRANSACTION PROCESSING

APPLICATION PROCESSING

SYSTEM PROCESSING

INTEGRATION OF SYSTEM

BIS, DWS, DMS, SPAs

PRODUCTION SYSTEM

QUERY PROCESSING

EXCEPTION REPORTING

DATABASE, KNOWLEDGE BASE

DECISION SUPPORT SYSTEM

OPERATIONAL RESEARCH AND APPLICATION PACKAGES

EXPERT, AND ARTIFICIAL INTELLIGENCE SYSTEM

PROCESSING

MIS MODEL

General Model of Management Information System


� The MIS is the arrangement of the data processing and information system inan orderly manner to support the management in achieving the objectives.

� The MIS boundaries cross the limits of the organization and draw the data fromthe external source to the organization.

� MIS is design to provide the information which is exceptional in nature from thebusiness point of view. By nature, MIS is an open system interfacingcontinuously with the internal and external environment and is self organizing tomeet the ever increasing and changing information need of the organization.

� This is made possible by organizing the MIS in hierarchical structure.

� The performance of the MIS design starts disorganizing in the postimplementation period and it is necessary to provide the negative entropy tobring back the system to its original balance.

� Though the MIS design as an open system, its failure arise on account of thedegree of flexibility kept in the system.

� It is observed that the core systems are not required to change but theperipheral systems often undergo a change.