2 Information System Development

8/13/2019 2 Information System Development

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Objectives Overview

Define system developmentand list the system

development phases

Identify the guidelines for

system development

Discuss the importance ofproject management,

feasibility assessment,

documentation, and data

and information gathering

techniques

Explain the activities

performed in the planningphase

Discuss the purpose of the

activities performed in theanalysis phase

Describe the various toolsused in process modeling

Discovering Computers 2010: Living in a Digital World

Chapter 12

1See Page 619

for Detailed Objectives


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Objectives Overview

Describe the various

tools used in object

modeling

Explain the activities

performed in the

design phase

Recognize the develop

programs activity is

part of systemdevelopment

Discuss the activities

performed in theimplementation phase

Discuss the purpose of

the activities

performed in theoperation, support, and

security phase


Chapter 12

2See Page 619

for Detailed Objectives


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What is System Development?

System developmentis a set of activities

used to build an information system

A systemis a set of

components that

interact to achieve a

common goal

An informationsystem (IS) is a

collection of

hardware, software,

data, people, and

procedures that work

together to produce

quality information

System development

activities are grouped

into phases, and is

called the system

development life

cycle(SDLC)


Chapter 12

3Page 620


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Chapter 12

4Pages 620621

Figure 12-1


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System development should follow three general

guidelines:


Chapter 12

5Page 621

Group activities or tasks into phases

Involve users

Define standards


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System development should involve representatives from each

department in which the proposed system will be used


Chapter 12

6Page 622

Figure 12-2


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Project managementis the process of planning,

scheduling, and then controlling the activities during

system development

To plan and schedule a project efficiently, the projectleader identifies:


Chapter 12

7Page 623

Project scopeRequired

activities

Time estimates

for each activity

Cost estimates

for each activity

Order of

activities

Activities that

can take place at

the same time


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Chapter 12

8Page 623

Figure 12-3a

Click to view Web Link,click Chapter 12, Click WebLink from left navigation,then click Gantt Charts belowChapter 12

A popular tool

used to plan

and schedule

the time

relationships

among project

activities is a

Gantt chart
http://www.scsite.com/dc2010cp/ch12/weblink/


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Chapter 12

9Page 624

Figure 12-3b

Click to view Web Link,click Chapter 12, Click WebLink from left navigation,then click PERT Charts belowChapter 12

A PERT chart

also can beused for

planning and

scheduling time


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Feasibilityis a measure of how suitable the

development of a system will be to the

organization


Chapter 12

10Pages 624 - 625

Operational

feasibility

Schedule

feasibility

Technical

feasibility

Economic

feasibility


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Documentationis the collection and

summarization of data and information

A project notebook contains all documentation for a

single project

Users and IT professionals refer to existing

documentation when working with and modifying

current systems


Chapter 12

11Page 625


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During system development, members of the project

team gather data and information using several

techniques


Chapter 12

12Pages 625626

Figure 12-4

Review

documentationObserve Survey

Interview JAD Sessions Research


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Who Initiates a System

Development Project?

A user may request a new or modified system

Organizations may want to improve hardware, software, or other

technology

Situations beyond an organizations control might require a change

Management might mandate a change

A user may request a new or modified information system using a request

for system services or a project request


Chapter 12

13Page 626


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Who Initiates a System

Development Project?


Chapter 12

14Page 627

Figure 12-5


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Planning Phase

The planning phasefor a project begins when the

steering committee receives a project request

Four major activities are performed:


Chapter 12

15Page 628

Review and

approve theproject requests

Prioritize the

project requests

Allocate

resources

Form a project

developmentteam


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Analysis Phase

The analysis phaseconsists of two major

activities:


Chapter 12

16Pages 629 - 631

Conduct a preliminary

investigation

Determines and

defines the exact

nature of the problem

or improvement

Interview the user who

submitted the request

Perform detailed

analysis

Study how the current

system works

Determine the userswants, needs, and

requirements

Recommend a solution


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Analysis Phase


Chapter 12

17Pages 629630

Figure 12-6

Click to view Web Link,click Chapter 12, Click WebLink from left navigation,then click Feasibility Studybelow Chapter 12


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Analysis Phase

Process modeling(structured analysis and design) is an

analysis and design technique that describes processes

that transform inputs into outputs


Chapter 12

18Page 631

Entity-

relationship

diagrams

Data flow

diagrams

Project

dictionaryClick to view Web Link,click Chapter 12, Click WebLink from left navigation,then click Process Modelingbelow Chapter 12


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Analysis Phase

An entity-relationship

diagram(ERD) is a tool

that graphically shows

the connections amongentities in a system

Entities are objects in

the system that have

data


Chapter 12

19Page 632

Figure 12-7


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Analysis Phase

A data flow diagram

(DFD) is a tool that

graphically shows the

flow of data in a system Data flows

Processes

Data stores

Sources


Chapter 12

20Page 632

Figure 12-8


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Analysis Phase

A decision tableis a table that

lists a variety of conditions

and the actions that

correspond to each condition

A decision tree also shows

conditions and actions, but it

shows them graphically


Chapter 12

22Page 633


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Analysis Phase

The data dictionarystores the data items name,

description, and other details about each data

item


Chapter 12

24Page 634

Figure 12-12


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Analysis Phase

Object modelingcombines the data with the processes

that act on that data into a single unit, called an object

UML(Unified Modeling Language) has been adopted as a

standard notation for object modeling and development UML includes 13 different diagrams

Two diagrams include:


Chapter 12

25Page 634

Use case

diagramClass diagram

Click to view Web Link,click Chapter 12, Click WebLink from left navigation,then click UMLbelow Chapter 12


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Analysis Phase

A use case diagram

graphically shows how

actors (users) interact

with the informationsystem

Diagrams are

considered easy to

understand


Chapter 12

26Page 634

Figure 12-13


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Analysis Phase

A class diagramgraphically showsclasses and subclassesin a system

Each class can have oneor more subclasses

Subclasses useinheritance to inheritmethods and attributesof higher levels


Chapter 12

27Page 635

Figure 12-14


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Analysis Phase

The system proposal assesses the feasibility of

each alternative solution

The steering committee discusses the system

proposal and decides which alternative to pursue


Chapter 12

28Pages 635 - 636

Packaged

software

Custom

software Outsourcing

Click to view Web Link,click Chapter 12, Click WebLink from left navigation,then click Vertical MarketSoftware below Chapter 12


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Design Phase

The design phaseconsists of two major activities


Chapter 12

29Page 638

Acquire hardware

and software

Develop all of the

details of the new

or modified

information system


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Design Phase

To acquire the necessary hardware and software:


Chapter 12

30Pages 638 - 640

Use researchtechniques such ase-zines

Identify technical

specifications

RFQ, RFP, or RFI issent to potentialvendors or VARs

Solicit vendor

proposals Various techniquesare used todetermine the bestproposal

Test and evaluate

vendor proposals

Systems analystmakesrecommendation to

steering committee

Make a decision

Click to view Web Link,click Chapter 12, Click WebLink from left navigation,then click E-Zines belowChapter 12


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Design Phase

The next step is to develop detailed design

specifications

Sometimes called a physical design


Chapter 12

31Page 640

Database

design

Input and

outputdesign

Program

design


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Design Phase

Systems analysts typically develop two types of

designs for each input and output


Chapter 12

32Page 641

Figures 12-1812-19

Mockup Layout chart


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Design Phase

A prototype(proof of concept) is a working model

of the proposed system

Prototypes have inadequate or missing documentation

Users tend to embrace the prototype as a final system

Should not eliminate or replace activities


Chapter 12

33Pages 641 - 642


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Design Phase

Computer-aided software engineering (CASE)

tools are designed to support one or more

activities of system development

CASE tools sometimes contain the following tools:


Chapter 12

34Page 642

Project

repositoryGraphics Prototyping

Quality

assurance

Code

generatorHousekeepingClick to view Web Link,click Chapter 12, Click Web

Link from left navigation,then click CASE Toolsbelow Chapter 12


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Design Phase


Chapter 12

35Page 642

Figure 12-20


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Design Phase

Many people should review the detailed design

specifications

An inspection is a formal review of any system

development deliverable

A team examines the deliverables to identify errors


Chapter 12

36Page 642


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Implementation Phase

The purpose of the implementation phaseis to

construct the new or modified system and then

deliver it


Chapter 12

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Develop

programs

Install and

test the new

system

Train users

Convert to

the new

system


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The program development life cycle follows these

steps:


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1 Analyze the requirements

2 Design the solution

3 Validate the design

4 Implement the design

5 Test the solution

6 Document the solution


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Various tests should be performed on the new

system


Chapter 12

39Page 644

Unit test

Verifies that

each

individual

program orobject works

by itself

Systems test

Verifies that

all programs

in an

applicationwork

together

properly

Integrationtest

Verifies that

an

application

works withother

applications

Acceptancetest

Checks the

new system

to ensure

that it workswith actual

data


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Traininginvolves showing users exactly how they

will use the new hardware and software in the

system

One-on-one sessions

Classroom-style lectures

Web-based training


Chapter 12

40Page 644

Figure 12-21


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One or more of four conversion strategies can be

used to change from the old system to the new

system


Chapter 12

41Pages 644645

Figure 12-22


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Operation, Support, and Security Phase

The purpose of the operation, support, and

security phaseis to provide ongoing assistance for

an information system and its users after the

system is implemented

Discovering Computers 2010: Living in a Digital WorldChapter 12

42Page 645

Perform

maintenance

activities

Monitor

system

performance

Assess systemsecurity

Click to view Web Link,click Chapter 12, Click WebLink from left navigation,then click Chief SecurityOfficer below Chapter 12


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Operation, Support, and Security Phase

A computer security planshould do the following:


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Identify all

information

assets of an

organization

Identify all

security risks

that may cause

an information

asset loss

For each risk,identify the

safeguards that

exist to detect,

prevent, and

recover from aloss


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Summary

System

development

phases

Guidelines for

system

development

Activities that occurduring system

development

Activities

performed duringeach system

development phase


45Page 647


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Living in a Digital World

Discovering

Computers 2010

2 Information System Development

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