Discovering Computers 2011

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Living in a Digital World

Discovering

Computers 2011

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Objectives Overview

Define system development and list the system development phases Identify the guidelines for system development

Discuss the importance of project management, feasibility assessment, documentation, and data and information gathering techniques Explain the activities performed in the planning phase

Discuss the purpose of the activities performed in the analysis phase Describe the various tools used in process modeling

Discovering Computers 2011: Living in a Digital World Chapter 12

See Page 619 2

for Detailed Objectives

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Objectives Overview

Describe the various tools used in object modeling Explain

Recognize Discuss

Discuss the purpose of the activities performed in the operation, support, and security phase

See Page 619 3

for Detailed Objectives

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What is System Development?

System development

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What is System Development?

Pages 620 – 621 5 Figure 12-1

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What is System Development?

• System development should follow three general guidelines:

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What is System Development?

• System development should involve representatives from each department in which the proposed system will be used

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What is System Development?

• Project management is the process of planning,

scheduling, and then controlling the activities during system development

• To plan and schedule a project efficiently, the project leader identifies:

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Project scope

Required 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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What is System Development?

Page 623 9 Figure 12-3a

Click to view Web Link,

click Chapter 12, Click Web Link from left

navigation, then click Gantt Charts below Chapter 12

A popular tool used to plan and schedule

the time relationships among project

activities is a

Gantt chart

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What is System Development?

Page 624 10 Figure 12-3b

navigation,

then click PERT Charts below Chapter 12

A PERT chart also can be

used for

planning and

scheduling time

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What is System Development?

• Feasibility is a measure of how suitable the development of a system will be to the

organization

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What is System Development?

• Documentation is 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

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What is System Development?

• During system development, members of the project team gather data and information using several

techniques

Pages 625 – 626 13 Figure 12-4

Review documentation Observe

Survey

Interview

JAD Sessions

Research

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Who Initiates a System Development Project?

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Who Initiates a System Development Project?

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Planning Phase

• The planning phase for a project begins when the steering committee receives a project request

• Four major activities are performed:

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Analysis Phase

• The analysis phase consists of two major activities:

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Conduct a

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Analysis Phase

Pages 629 – 630 18 Figure 12-6

navigation,

then click Feasibility Study below 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

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Entity-relationship diagrams Data flow diagrams

Project dictionary

navigation,

then click Process Modeling below Chapter 12

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Analysis Phase

• An entity-relationship diagram (ERD) is a tool that graphically shows the connections among entities in a system

• Entities are objects in the system that have data

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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

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Analysis Phase

• The project dictionary contains all the

documentation and deliverables of a project

• Structured English is a style of writing that describes the steps in a process

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Analysis Phase

A

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Analysis Phase

Decision table Decision tree

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Figures 12-10 – 12-11

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Analysis Phase

• The data dictionary stores the data item’s name, description, and other details about each data item

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Analysis Phase

• Object modeling combines 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:

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Use case diagram Class diagram

navigation, then click UML below Chapter 12

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Analysis Phase

• A use case diagram graphically shows how actors (users) interact with the information system

• Diagrams are

considered easy to understand

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Analysis Phase

• A class diagram graphically shows

classes and subclasses in a system

• Each class can have one or more subclasses

• Subclasses use

inheritance to inherit methods and attributes of higher levels

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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

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Packaged software Custom software Outsourcing

navigation,

then click Vertical Market Software below Chapter 12

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Design Phase

• The design phase consists of two major activities

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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:

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Use research techniques such as Use research techniques such as

navigation,

then click E-Zines below Chapter 12

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Design Phase

• The next step is to develop detailed design specifications

– Sometimes called a physical design

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Database design

Input and output design

Program design

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Design Phase

• Systems analysts typically develop two types of designs for each input and output

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Figures 12-18 – 12-19

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

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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:

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Project repository Graphics

Prototyping

Quality assurance Code generator Housekeeping

navigation,

then click CASE Tools below Chapter 12

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Design Phase

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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

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Implementation Phase

• The purpose of the implementation phase is to construct the new or modified system and then deliver it

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Implementation Phase

• The program development life cycle follows these steps:

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1

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Implementation Phase

• Various tests should be performed on the new system

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Unit test

Integration test

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Implementation Phase

• Training involves 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

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Implementation Phase

• One or more of four conversion strategies can be used to change from the old system to the new system

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Operation, Support, and Security Phase

• The purpose of the operation, support, and

security phase is to provide ongoing assistance for an information system and its users after the

system is implemented

Pages 645 - 646 43

navigation, then click Chief

Security Officer below Chapter 12

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Operation, Support, and Security Phase

• A computer security plan should do the following:

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Video: Create a Hidden Operating System

45

CLICK TO START

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Summary

System development phases

Guidelines for system development

Activities that occur during system development

Activities performed during each system development phase

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