INTRO TO INFORMATION SYSTEMS DEVELOPMENT

IS 340

BY

CHANDRA S. AMARAVADI

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OVERVIEW

IntroductionSystem definedCharacteristics of systemsGood systems System development methodologies

The Software development life cycleMethods of AnalysisDesignDesign principles

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INTRODUCTION

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INTRODUCTION..

Information systems development is primarilyconcerned with the process of developing the softwarecomponent of the system.

e.g. payroll, inventory, web-based ordering etc.

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IMPORTANCE OF IS DEVELOPMENT

Five million programmers

IS needed for business operations

One bank has 40,000 programs

In many cases, IS -> competitive advantage

Most important part of the economy

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System: any set of related elements (which are under consideration) working together towards the common purpose of transforming inputs into outputs

Examples: transportation network, education, building...

In the IS context: a system is any part (or whole) of the organization which satisfies the definition above

Examples:?

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system can be open or closedhave inputs, processes and outputshave a boundaryhave subsystems (subsystems share the same characteristics)have a life cycle

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How would you view a bank as a system?

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Prototyping - developing an initial version (model) of the system using quick & dirty techniques and modifying it later.

Traditional - go through a structured process of identifying requirements etc.

Object oriented – identifies objects and methods. The analysis focusses on identifying object relationships and programming the methods. (not discussed further)

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SYSTEM DEVELOPMENT METHODOLOGIES

Requirements

System

User

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PROTYPING

THE CONVENTIONAL METHOD

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THE SOFTWARE DEVELOPMENT LIFE CYCLE

PLANNING

ANALYSIS

DESIGN

IMPLEMENTATION

MAINTENANCE/SUPPORT

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Systems go through a structured process of development

Traditional

Planning/feasibility study - scope and feasibility of the system

Analysis - identify & document the requirements

Design - develop program/data/user interface structure to meet the requirements

Implementation - coding/testing/installation of the program; hiring of programmers/get HW/SW

Maintenance/support - keep the system up to date with changes (business [e.g. new accounting methods, new products]; HW/SW; bugs, etc.)

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PLANNING

Interview Employees from top down

Identify processes and information classesProcess – group of related activities

Information class -- collection of information

Develop process vs. info class matrix

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Student Info Faculty Course Info …HousingParkingTranscriptsRegistrationCourse schedulePayroll

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ANOTHER EA MATRIX

Adapted from [http://dlnt20.fsa.usda.gov/scdm/model.htm]

County Activity Tract Parcel Owner Unit

Land use X

Rds & Bldgs X

Taxation X X

Waste disp.

Water supply

Cons. programs

Gives a broad understanding of processing Gives a broad understanding of processing

requirementsrequirements

Can be used as a basis for database designCan be used as a basis for database design

ENTERPRISE ANALYSIS..

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METHODS OF ANALYSIS

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TECHNIQUES OF ANALYSIS:

Data Flow Diagramming (DFD) Data modelling

Key Performance Indicators (a.k.a. CSFs)

ANALYSIS METHODS

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Cust.

Invoice

Vendor

1.0 Processorder

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process

file

data flow

external entity

FOR DISCUSSIONClassify each of the following as process, external entitydata store or information flow:

Review inventoryA directory of manufacturersThe securities and exchange commission Production planA p.o. forwarded to a managerVerify a P.O.A transcriptSending a loan applicationCourse schedulePrepare balance sheet

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DFD GUIDELINES

Connect processes first and add other details later

Process names must be V+N No restriction on naming of files/external

entities

Sub-systems must be separate Sub-systems are numbered using the Dewey

system (e.g. 1.1, 1.2, 1.3; 1.1.1, 1.1.2…)The total # of inputs and outputs of the

subsystem must match with those of its immediate parent

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BALANCE A RVLE

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1.0

1.1 1.2

A technique for identifying information requirements of executivesKPIs are critical to the success of the firmKPIs are a.k.a Critical Success Factors (CSFs)

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KEY PERFORMANCE INDICATORS

Identify KPIskey profit & loss items key resources critical processes

Identify information measures

Note: KPIs are also known as Critical Success Factors

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KPIs FOR A COMPANY LIKE CATERPILLAR

key profit & loss items: #orders, order quantities, raw material inventory, finished goods inventory

key resources: raw materials, senior engineers

critical processes:engineering design; sales & marketing

DISCUSSION

With what type of systems are KPIs associated with?

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DESIGN

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The purpose of design is to identify a program / interface / data structure to meet the requirements

The design technique is referred to as “Transform Analysis”

What are the inputs to design?

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Identify Central Transform (C-T)Dangle DFD from C-TResult is a structure chart

a

b

c

fed

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(is a design technique)

a b c

f .

e .

d

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DESIGN PRINCIPLES

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Coupling

Cohesion

To design good systems it is necessary to follow design principles

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Coupling - the extent to which two (or more) modules are interconnected

Module A

Module BModule A

Module B

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COUPLING..

Module A Module B

Call BGo back to A

Go to B

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Cohesion - the extent to which elements in a module are related

Module1read tax ratecompute taxes = tax rate * revenuemove taxes to detail linewrite detail line

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Module2write main headingswrite subheadingswrite column headingscompute taxes = tax rate * revenue

Which of the following are examples of systems?: Motivation, Accounting, Competition, Core competencyDo subsystems share the same characteristics as a system?Is KPI an analysis or a design technique?What is the design technique called?During what stage of the SDLC is coding done?What analysis technique is used to identify the information needs of top management?What are some KPIs for a computer manufacturer?What is Enterprise Analysis used for?What sort of benefits can you expect from a good information system?

DISCUSSION QUESTIONS

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