01 Isad Intro Rajon

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S. A. AHSAN RAJON

[email protected]

http://sites.google.com/site/ahsanrajon

+88-01911510286



S. A. AHSAN RAJON 2

� SAD

System Analysis and Design

� ISAD

Information System Analysis and Design



S. A. AHSAN RAJON 3

� Easy course; but uninteresting;

No math; No programming; No logic;

Simply ́ voluminousµ texts.

� Traditional learning«

� How to do well in exam?

Understand the topic«

Note down the ´Key pointsµ extracted from the texts.

Try to match with your usual ´day-to-dayµ concept.



S. A. AHSAN RAJON 4

� At LEAST THREE class tests«

If you want more; ... [ ??? ]

� Class Test Schedule

� Week will be fixed by me«.

� Dates will be SELECTED by you

� DATES are absolute; not even ask«



S. A. AHSAN RAJON 5

� BOOKS

SYSTEMS ANALYSIS AND DESIGN

� Author: Elias M. Awad

� Edition: Second Edition or Any recent

� Publisher: Galgotia Publications

Modern System analysis and Design

� Author: Jeffery A. Hoffer, Joey F. George, Joseph S. Valacich, Prabin K.

Panigrahi

� Edition: Fourth Edition or recent

� Publisher: Pearson

SYSTEM ANALYSIS AND DESIGN METHODS

� Author: Jeffery L. Whitten

� Edition: Fifth Edition or recent

� Publisher: McGraw Hill



S. A. AHSAN RAJON 6

� Reference Book

Information Systems: A Management Perspective

� Author: Steven Alter

� Edition: Third Edition or Any recent

� Publisher: Pearson Education

� OTHER RESOURCES

Should be provided

� Lecture Slides

Oops!! SAD with SAD lecture Slides«



S. A. AHSAN RAJON 7



S. A. AHSAN RAJON 8

� Systems Concepts

� System Development Life Cycle

� Role of System Analyst

� System planning

� Information gathering

� Tools for structured analysis

� Cost and benefit analysis

� System and system-component design

� Miscellaneous



S. A. AHSAN RAJON 9

� Software Systems are based on Information Systems

Development of Software requires understanding the ´existing

system set-upµ

Revealing existing set up requires you to understand the

organizational paradigm.

� How to have requirement Analysis?

Then you need data collection

�

How to collect data?

� How to record Data?

� How to get a result from that data?



S. A. AHSAN RAJON 10

� Consider

University Management System.

Employee information and Payroll management System.

Company Automation System/production control system

National ID project.

Electronic voting system.

SMS-based information management system.




� For any System

What is the current system?

How the current system works?

What are the advantages & disadvantages i.e. problems of

present system?

How Information Technology may be applied (if not applied in

the current system)?

� Or how the adopted Information Technology based System may be

enhanced?

Which advantages are obtained by applying the new systems.

� What are the limitations/disadvantages/pitfalls of new systems?

How to administer/Manage the new system?




� Derived from Greek word ´systemaµ which means

An organized relationship among functioning units or

components.

A system exists because it is designed to achieve one or

more objectives.

� A system is an orderly grouping of interdependent

components linked together according to a plan to

achieve a specific objective.




� Component may refer to

Physical parts

� engines, wings of aircraft or wheels of a car

Managerial steps

� Planning, Organizing, Directing and Controlling

Or a subsystem of multilevel structure




� Components of a system may be simple or

complex , basic or advanced .

� There may be a single computer or even be a

series of intelligent terminals linked to amainframe.

In either case, each component is part of the total system

and has to share do its share of work for the system to

achieve the intended goal.




� A system must be designed to achieve a

predefined objective.

� I

nterrelationships and interdependence mustexist among the components.

� The objectives of the organization as a whole hasa higher priority than the objectives of the

subsystem.




� Organization

� Interaction

� Interdependence

� Integration

� Central Objective




� Implies Structure and Order

� Arrangements that helps to achieve objectives

� Hierarchical Relationship

Such Arrangement portraying a system³subsystem

relationship

Defines authority structure

Specifies formal flow of communication

Formulizes the chain of command




� Refers to the manner in which each component

functions w ith other components of the system.

Interrelationship among the central processing unit,

memory and other hardware components enables the

computer system to perform.




� Interdependence means that parts of the

organization or computer system w orks together .

� They are coordinated and linked together

according to a plan.� One subsystem depends on input o f another

subsystem f or proper functioning; that is output

of one subsystem is required input of anothersubsystem.

� N o subsystem can function in isolation.




� Task interdependence in computer based systems

Userarea

System

AnalysisDesign

Programm

ing

Operatio

ns




University

Admission

Administra

tion

personnel

Finance

Courses

personnel

Employm

ent

Accounts

Safety

Miscella

neous

Benefits

Accounts

Grants

Internal

earnings

Consulta

ncy

Researc

hOutcome

Major Subsystem

Intermediate Subsystem

Minor Subsystem




� Refers to the holism of a system.

� Integration is concerned with how a system is

tied together .

� More than sharing a physical part.

� It means that parts of the system works together

within the system even though the each part

per f orms a unique function.




� Objectives may be real or stated.

� Achievement of one objective may be a must for

moving towards achievement of another one.




� An information system is an

arrangement of people, data, process, information

presentation and information technology

that interact to support an improved day-to-day operations

in a business

as well as support the problem solving and decision making

needs to management and users.

[Whitten]




� Information system may be defined as

a set of devices, procedures and operating systems

designed around user based criteria to produce information

and

communicate it to the users

for planning, control and performance




� Information technology is a contemporary term

that describes the combination of computer

technology (hardware and software) with

telecommunication technology (data, voice

networks)




� Information system analysis and design is the complex

organizational process whereby computer basedorganizational systems are developed and maintained.

� Main goal is to improve employee efficiency by applying

software solutions to key business tasks

� A structured approach must be used in order to ensure

success

[ Hoffer ]




� Types of Systems

Physical and abstract

Open or closed

Man-made information system




� PHYSICAL SYSTEMS«

T angible entities; may be static or dynamic in operation

� E.g. in computer centers, computer hardware are static,

programs stored into computers are dynamic

Data, programs, output and applications change as users·

demands

� ABSTRACT SYSTEMS

Conceptual or non-physical entities

� E.g. model; representation of real or planned systems.




� TYPES of SYSTEM MODELS

Schematic Model

� Two dimensional chart describing system elements and linkage

Flow-System Model

� Concerned with flow of information

Static system model

� Exhibits pair relationship; e.g. activity-time or cost-quantity

� Gantt chart

Dynamic System Model

� Describes ongoing consistently changing system

� Trend analysis, probabilistic model.




� Open Systems

Permits interactions across its boundaries.

Receives input from and delivers output to outside.

Information system falls into this category since it must

adapt to the changing demands of the user.

� Closed Systems

Isolated from environmental influences.

In reality completely closed system is rare.




� CHARACTERISTICS OF OPEN SYSTEMS

Input from outside

Entropy

Process, Output and Cycles

Differentiation

Equi-finality

� No matter how you reach the destination; the matter is, the

costs and outcome would be the same.




� Input from outside

Open Systems are Self adjusting and self adapting

When functioning properly Open Systems reaches into

Steady State or equilibrium

� Entropy

All dynamic systems tend to run down over time resulting

in entropy or loss of energy

Open systems resist entropy by seeking new inputs or

modifying the processes to return to a steady state.




� Process, Output and Cycles

Produce output, operate in cycles, follows continuous

processing path

� Differentiation

Have a tendency towards an increasing specialization of

functions

� Equi-finality

Implies that, goals are achieved through differing courses

of actions and a variety of paths.




� Man-Made Information systems

Recall definition of information systems.




� Types of (Man-made) Information System

Formal Information Systems

Informal Information Systems

Computer-based Information Systems




� Based on organization based on organization

represented by the organization chart

This chart is a Map of positions and their authority relationships,

indicated by boxes and connected by straight lines.

� concerned with the pattern of authority,

communication and work flow

� Information is formally disseminated in instructions,

memos or reports from top management to the

intended users in the organizations� Also allows feedback up the chain of command for

follow-up.




� Organizational charts depict the hierarchy of

employees in an organization




� STRATEGIC INFORMATION

Refers to long range planning policies that are of direct

interest to upper management.

Information such as trends in financial investment, human

resources changes would be of top company officials who

are responsible for developing policies and determining

long range goals.

� This type of information is achieved by DECISION SUPPORT SYSTEM (DSS)




� MANAGERIAL INFORMATION

Of direct use to middle management and department

heads for implementation and control

� E.g. sales analysis, cash flow projections, financial statements

This type of information is of use in short and

intermediate range planning.

� Maintained with the aid of Management Information System

(MIS)




� OPERATIONAL INFORMATION

Short term; daily information used to operate

departments and enforce day to day rules and regulations

of the business.

� E.g. daily employee absence sheets, overdue purchase orders,

current stock available for sale

� Operational information is established by Data Processing

Systems (DPS)




Strategic

Planning Information

Management control information

Operational information

UPPER

MIDDLE

LOWER

DSS

Decision Support System

MIS

Management

Information System

DPS

Data Processing

System




� employee based system

designed to meet personal and vocational needs and to help solvework related problems.

� Knowledge about the inner working of the employee based

system is useful during the exploratory face of the

analysis. Employee co-operation and participation are crucial in training users.

� Since computer can·t provide reliable information without

user staff support, a proper interface with the informalcommunication channels could mean the difference the

between the success and the failure of the system.




� A third class of the information system realize

on the computer for handling the business

applications.

Transaction processing system (TPS)

Management Information System (MIS):

Decision Support System (DSS)




� The level of the manager in the organization is an

important factor in determining the kind of informationneeded to solve a problem.

Lower level management needs detailed internal information to make

day to day relatively structured controlled decisions higher level

management.

For whom the long range objectives are the primary concerns requires

summarized information from a variety of sources to attain goals.

� MIS is a person machine system and a highly integrated

grouping of information processing function designed to

provide management with a comprehensive picture ofspecific information of specific operations.




� The primary users of MIS are middle and top management,

operational managers and support staff.� Middle and top management use MIS for

preparing forecasts,

special request for analysis

long range plans and

periodic reports.

� Operational managers use MIS primarily for

short range planning and

periodic and exception reports.

� The support staff finds MIS useful for the

special analysis of information and

reports to help management in planning and control.




� MIS provides limited support to top level management

for decision making whereas DSS advances the capabilitiesof MIS.

It assists management in making decisions.

� Decision support system stands for ²

Decision

� emphasizes decision making in problem situation.

Support

� Requires computer added decision situation enough structure to

permit computer support.

System

� Combines the integrated nature of problem solving suggesting a

combine ¶man· , machine and decision involvement.




� DSS results from adding

external data sources,

accounting and statistical models and

interactive query capabilities.

� The outcone is a system designed to serve all

levels of management and top level

managements in particular with ´w hat i f µunstructured problem situation.







� Harvard Simon described decision making as a

three phase continuous process model.

Pro lem Recognition

Gathering

information a out a

pro lem

Calling for a decision

Develop alternative

Solutions

Evaluate Alternative

Solutions

Actual Selection of

a solution for

implementation

Intelligence Design Choice




� Expert systems are designed to analyze data and

produce a recommendation, diagnosis, or decisionbased on a set of facts and rules

Knowledge base

� Inference engine

� Knowledge engineering Expert system shell

Fuzzy logic

� A neural network uses computer circuitry to

simulate the way a brain might processinformation, learn, and remember




An expert system is

characterized y its a ility to:

Replicate the reasoning

of a human expert

Work with internal or

external data

Produce a

recommendation or

decision



S A AHSAN RAJON 53

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01 Isad Intro Rajon