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Chapter 1

System Development Environment

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Learning Objectives

Define information systems analysis and design

Describe the organizational roles involved in information systems development

1.21.2

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Learning Objectives

Describe four types of information systems: Transaction Processing Systems (TPS) Management Information Systems (MIS) Decision Support Systems (DSS) Expert Systems (ES)

Describe the information systems development life cycle (SDLC)

1.31.3

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Learning Objectives

Discuss alternatives to the systems development life cycle

Discuss the role of computer-aided software engineering (CASE) tools in systems development

Discuss project management (PM)

1.41.4

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Introduction What is a system ?

System is a set of components that work together in an environment for a specific function in order to achieve certain objectives.

What is information? Information is data that has been

processed or worked for a specific objective.

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Introduction Information System

An Information System (IS) is an organization of data, processes, interfaces, networks, people, and technology which are related and support daily business operations (Data Processing) or support management in problem solving and decision making (Information Services).

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Introduction

Information Systems Analysis and Design Complex process whereby computer-

based information systems are developed and maintained

Application Software Result of system analysis and design Designed to support specific

organizational functions or processes

1.51.5

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Introduction

Systems Analyst Organizational role most responsible

for analysis and design of information systems

Systems Analyst performs analysis and design based upon: Understanding of organization’s

objectives, structure and processes Knowledge of how to exploit

information technology for advantage

1.81.8

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Software Engineering Process Software engineering processes have been

developed to assist in analysis and design Consists of:

Methodologies A sequence of step-by-step approaches that

help develop the information system Techniques

Processes that the analyst follows to ensure thorough, complete and comprehensive analysis and design

Tools Computer programs that aid in applying

techniques1.111.11

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Organizational Responsibilities in Systems Development

IS Manager May have a direct role in systems

development if the project is small Typically involved in allocating

resources to and overseeing system development projects

Systems Analyst Key individuals in the systems

development process

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Organizational Responsibilities in Systems Development

Skills of a Successful Systems Analyst Analytical

Understanding of organizations Problem solving skills System thinking

• Ability to see organizations and information systems as systems Technical

Understanding of potential and limitations of technology Management

Ability to manage projects, resources, risk and change Interpersonal

Effective written and oral communication skills

1.111.11

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Organizational Responsibilities in Systems Development

Programmers Convert specifications into instructions that

the computer understands Write documentation and testing programs

Business Managers Have power to fund projects and allocate

resources Set general requirements and constraints for

projects

1.121.12

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Organizational Responsibilities in Systems Development

Other IS Managers/Technicians Database Administrator

Involved in design, development and maintenance of databases

Network and telecommunications experts Develop systems involving data and/or voice

communications Human Factors Specialists

Involved in training users and writing documentation

Internal Auditors Ensure that required controls are built into the

system1.131.13

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Users Users, also known as end users, are

persons who are working with the system in terms of data entry, reading reports and making decisions based on the information produced by the system.

Users are normally involved in determining requirements of the system during the IS system development process.

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Management

Management is responsible for endorsing and providing project allocation for IS development in the organization.

They are also responsible for supervising and driving the SD team in order to achieve organization objectives as well as enforcing the usage of system to all members of the organization.

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Types of IS and Systems Development

Transaction Processing Systems (TPS) Automate handling of data about business

activities (transactions) Management Information Systems (MIS)

Converts raw data from transaction processing system into meaningful form

Decision Support Systems (DSS) Designed to help decision makers Provides interactive environment for decision

making

1.161.16

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Types of IS and Systems Development

Expert Systems (ES) Replicates decision making process Knowledge representation describes

the way an expert would approach the problem

1.171.17

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Developing Information Systems and the SDLC System Development Methodology

Standard process followed in an organization

Consists of: Analysis Design Implementation Maintenance

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Systems Development Life Cycle

Traditional methodology for developing, maintaining, and replacing information systems

Consists of five phases: Planning Analysis Design Implementation Maintenance

1.191.19

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Systems Development Life Cycle

Phases are not necessarily sequential Each phase has a specific outcome

and deliverable Individual companies use customized

life cycles

1.201.20

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Phases of the Systems Development Life Cycle

Planning: Project Identification and Selection

Two Main Activities• Identification of need• Prioritization and translation of need into a development

schedule Helps organization to determine whether or not resources

should be dedicated to a project Project Initiation and Planning

Two Activities• Formal preliminary investigation of the problem at hand• Presentation of reasons why system should or should not be

developed by the organization

1.211.21

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Systems Development Life Cycle

Analysis Study of current procedures and

information systems Determine requirements

• Study current system• Structure requirements and eliminate

redundancies Generate alternative designs Compare alternatives Recommend best alternative

1.221.22

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Systems Development Life Cycle

Design Logical Design

Concentrates on business aspects of the system

Physical Design Technical specifications

Implementation Hardware and software installation Programming User Training Documentation

1.231.23

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Systems Development Life Cycle

Maintenance System changed to reflect changing

conditions System obsolescence

1.241.24

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Different Approaches to Software Development

Prototyping Building a scaled-down working version of the

system Advantages:

Users are involved in design Captures requirements in concrete form

Rapid Application Development (RAD) Utilizes prototyping to delay producing

system design until after user requirements are clear

1.251.25

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Different Approaches to Software Development

Joint Application Design (JAD) Users, Managers and Analysts work

together for several days System requirements are reviewed Structured meetings

1.261.26

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Improving IS Development Productivity

Computer-aided software engineering (CASE) tools Facilitate creation of a central

repository for system descriptions and specifications

1.271.27

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Importance of Project Management Project management may be the most

important aspect of systems development

Effective PM helps in Meeting customer expectations Satisfying budget and time constraints

PM skills are difficult and important to learn

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Managing the Information Systems Project Project

A planned undertaking of related activities to reach an objective that has a beginning and an end

Project management A controlled process of initiating,

planning, executing, and closing down a project

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Managing the Information Systems Project (cont.) Project manager

Systems analyst with management and leadership skills responsible for leading project initiation, planning, execution, and closedown

Deliverable The end product of an SDLC phase

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Phases of Project Management Process Phase 1: Initiation

Assess size, scope and complexity, and establish procedures

Phase 2: Planning Phase 3: Execution

Plans created in prior phases are put into action

Phase 4: Closedown Bring the project to an end

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PM Phase 2: Project Planning Define clear, discrete activities and the work needed

to complete each activity Tasks

Define project scope, alternatives, feasibility Divide project into tasks Estimate resource requirements Develop preliminary schedule Develop communication plan Determine standards and procedures Risk identification and assessment Create preliminary budget Develop a statement of work Set baseline project plan

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Some Components of Project Planning Statement of Work (SOW)

“Contract” between the IS staff and the customer regarding deliverables and time estimates for a system development project

The Baseline Project Plan (BPP) Contains estimates of scope, benefits,

schedules, costs, risks, and resource requirements

Preliminary Budget Cost-benefit analysis outlining planned

expenses and revenues

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Some Components of Project Planning (cont.) Work Breakdown Structure (WBS)

Division of project into manageable and logically ordered tasks and subtasks

Scheduling Diagrams Gantt chart: horizontal bars represent

task durations Network diagram: boxes and links

represent task dependencies

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Scheduling Diagrams:Gantt Chart

Special-purpose project management software is available for this.

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Scheduling Diagrams:Network Diagram

Special-purpose project management software is available for this.

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Monitoring Progress with a Gantt Chart

Red bars indicate critical path, lines through bars indicate percent complete.

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Representing and Scheduling Project Plans Gantt Charts Network Diagrams PERT Calculations Critical Path Scheduling

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Gantt Charts vs. Network Diagrams Gantt charts

Show task durations Show time overlap Show slack time in duration

Network diagrams Show task dependencies Do not show time overlap, but show

parallelism Show slack time in boxes

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Gantt Charts vs. Network Diagrams (cont.)

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Estimating Task Duration

PERT: Program Evaluation Review Technique

Technique that uses optimistic (o), pessimistic (p), and realistic (r) time estimates to determine expected task duration

Formula for Estimated Time: ET = (o + 4r + p)/6

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Example PERT Analysis

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Critical Path Scheduling

A scheduling technique whose order and duration of a sequence of task activities directly affects the completion date of a project

Critical path: the shortest time in which a project can be completed

Slack time: the time an activity can be delayed without delaying the project

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Critical Path Example(dependencies between tasks)

PRECEDING ACTIVITIES indicate the activities that must be completed before the specified activity can begin (see Fig. 3.19 for time estimates).

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Network diagram provides graphical illustration of dependencies between activities (see previous slide).

Critical Path Example

Network diagram shows dependencies

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Determining the Critical Path

Calculate the earliest possible completion time for each activity by summing the activity times in the longest path to the activity. This gives total expected project time.

Calculate the latest possible completion time for each activity by subtracting the activity times in the path following the activity from the total expected time. This gives slack time for activities.

Critical path – contains no activities with slack time.

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Critical Path Calculation

Early and late time calculations are determined and critical path established. (Note: Activity #5 can begin late without affecting project completion time).

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Critical Path Calculation (cont.)

Note the slack time in Activity #5.

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Summary

Information systems analysis and design Process of developing and maintaining an

information system

Four types of information systems Transaction Processing (TPS) Management Information Systems (MIS) Decision Support (DSS) Expert Systems (ES)

1.491.49

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Summary

Systems Development Life Cycle (SDLC) Planning Analysis Design Implementation Maintenance

1.501.50

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Summary

Alternatives to Systems Development Life Cycle Prototyping Rapid Application Development (RAD) Joint Application Design (JAD)

Computer-aided software engineering (CASE) tools

1.511.51

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Summary In this chapter you learned how to:

Explain the process of managing an information systems project.

Describe the skills required to be an effective project manager.

Explain critical path scheduling, Gantt charts, and Network diagrams.