MANAGEMENT INFORMATION SYSTEM

Chapter 7Systems Development

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OVERVIEW System approach The Software Development Life Cycle Traditional SDLC Prototyping Rapid Application Development (RAD) Phased Development Business Process Redesign (BPR) Strategic Initiation of BPR Projects Reverse Engineering Reengineering System Development Tools Process Modeling, DFD, Use Cases

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THE SYSTEMS APPROACH

John Dewey identified three series of judgments involved in resolving a controversy:

• Recognize the controversy.• Weigh alternative claims.• Form a judgment.

Systems approacha series of problem-solving steps that

ensure the problem is first understood, alternative solutions are considered, and the selected solution works.

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SERIES OF STEPS Preparation effort

prepares the problem solver by providing a systems orientation.

Business areas, level of management, resource flows

Definition effort consists of identifying the problem to be solved

and then understanding it. Solution effort

involves identifying alternative solutions, evaluating them, selecting the one that appears best, implementing that solution, and following up to ensure that the problem is solved.

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PHASES AND STEPS OF SYSTEMS APPROACH

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EACH BUSINESS AREA IS A SYSTEM

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DEFINITION EFFORT TERMINOLOGY

Problem trigger is a signal that things are going better or worse

than planned. Symptom

is a condition that is produced by the problem and is usually more obvious than the root cause of the problem.

Problem is a condition or event that is harmful or

potentially or beneficial or potentially beneficial to the firm.

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EACH PART OF THE SYSTEM IS ANALYZED IN SEQUENCE

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SELECT THE BEST SOLUTION

Analysisa systematic evaluation of options.

Judgmentthe mental process of a single

manager.Bargaining

negotiations between several managers.

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SYSTEMS DEVELOPMENT LIFE CYCLE

SDLCis an application of the systems approach

to the development of an information system.

Traditional SDLC stages are:PlanningAnalysisDesign ImplementationUse

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THE CIRCULAR PATTERN OF THE SYSTEM LIFE CYCLE

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PROTOTYPING Prototype

is a version of a potential system that provides the developers and future users with an idea of how the system in its completed form will function.

Prototyping is the process of producing a prototype.Best suited for small systems–reflecting

the prototyping influence.

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EVOLUTIONARY PROTOTYPE Evolutionary prototype

is continually refined until it contains all of the functionality that users require of the new system.

The steps involved are: Identify user needs.Develop prototype.

Integrated application developer Prototyping toolkit

Determine if the prototype is acceptable.Use the prototype.

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DEVELOPMENT OF AN EVOLUTIONARY PROTOTYPE

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REQUIREMENTS PROTOTYPE Requirements prototype

is developed as a way to define the functional requirements of the new system when users are unable to articulate exactly what they want.

Begin with the Evolutionary Prototype steps, then the next steps are: Code the new system; Test the new system; Determine if the new system is acceptable; Put the new system into production.

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DEVELOPMENT OF A REQUIREMENTS PROTOTYPE

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ATTRACTION OF PROTOTYPING Communications between the

developer and user are improved. The developer can do a better job of

determining the users’ needs. The user plays a more active role in

system development. The developers and the user spend

less time and effort developing the system.

Implementation is much easier because the user knows what to expect.

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POTENTIAL PITFALLS OF PROTOTYPING The haste to deliver the prototype may

produce shortcuts in problem definition, alternative evaluation, and documentation. The shortcut produces a “quick & dirty” effort.

The user may get overly excited about the prototype, leading to unrealistic expectations regarding the production system.

Evolutionary prototypes may not be very efficient.

The computer-human interface provided by certain prototyping tools may not reflect good design techniques.

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RAPID APPLICATION DEVELOPMENT RAD

is a term coined by James Martin. It refers to a development life cycle intended to produce systems quickly without sacrificing quality.

Information engineering (IE) is the name that Martin gives to his

overall approach to system development, which treats it as a firm-wide activity.

Enterprise is used to describe the entire firm.Essential to RAD is management, people,

methodologies, and tools.Best suited for large systems.

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PHASED DEVELOPMENT Phased development

is an approach for developing information systems that consists of six stages:

Preliminary investigationAnalysisDesignPreliminary constructionFinal constructionSystem test Installation.Best suited for systems of all sizes.

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THE STAGES OF THE PHASED DEVELOPMENT METHODOLOGY

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MODULE PHASES

System is subdivided into major modules such as:Report writer;Database;Web interface.

Number of modules varies with the system from one to a dozen or so.

Stages are performed separately for each module.

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ANALYSIS, DESIGN, AND PRELIMINARY CONSTRUCTION ARE PERFORMED ON EACH SYSTEM MODULE

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BUSINESS PROCESS REDESIGN Reengineering or Business process redesign

(BPR) is the process of reworking the systems. Systems include both those that process the

firm’s data and those that perform basic functions such as drilling for oil.

BPR affects the firm’s IT operations in two ways: Aids in the redesign of old information systems

(legacy systems); Applies to the redesign of information systems

to support major operations. Usually initiated at strategic management

level

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TOP-DOWN INITIATION OF BPR PROJECTS

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STRATEGIC INITIATION OF BPR Reverse engineering

is the process of analyzing an existing system to:

Identify its elements and their interrelationships;

Create documentation at a higher level of abstraction than currently exists.

Functionality is the job that it performs. Reengineering

is the complete redesign of a system with the objective of changing its functionality.

Forward engineering is given to the process of following the SDLC

in the normal manner while engaging in BPR.

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BPR COMPONENTS

BPR components can be applied separately or in combination.

Functional quality is a measure of what the system does.

Technical quality is a measure of how well it does it.

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BPR COMPONENT SELECTION IS BASED ON BOTH FUNCTIONAL AND TECHNICAL QUALITY

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METHODOLOGIES IN PERSPECTIVE Traditional SDLC

is an application of the systems approach to the problem of system development; contains all elements.

Prototyping is an abbreviated form focusing on the definition

and satisfaction of user needs. RAD

is an alternative approach to the design and implementation phases of SDLC.

Phased development uses traditional SDLC and applies it in a modular

fashion.

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SYSTEM DEVELOPMENT TOOLS Process modeling was first done with

flowcharts. ISO standardsUse of 20+ symbols

Data flow diagrams (DFD) is a graphic representation of a system

that uses four symbol shapes to illustrate how data flows through interconnected processes.

DFDs are excellent for modeling processes at a summary level.

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DATA FLOW DIAGRAM SYMBOLS Terminator

describes an environmental element, such as a person, organization, or another system.

Environmental elements exist outside the boundary of the system.

Process is something than transforms input into output.

Data flow consists of a group of logically related data elements

that travel from one point or process to another; can diverge and converge.

Data storage is a repository of data.

Connector contains the number of the process that provides the

data flow.

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A DFD OF A SALES COMMISSION SYSTEM

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LEVELED DATA FLOW DIAGRAMS Leveled DFDs is used to describe the hierarchy

of diagrams, ranging from context to lowest-level n diagram.

Diagram identifies the major processes of a system. Use additional DFDs to achieve documentation at both

a more summarized and a more detailed level. Context diagram is a diagram that documents

the system at a more summarized level. Positions the system in an environmental context.

Figure n diagram is a diagram that provides more detail. n represents the # of processes on the next higher

level. Documents a single process of a DFD in greater detail

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A CONTEXT DIAGRAM OF A SALES COMMISSION SYSTEM

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A FIGURE 4 DIAGRAM OF A SALES COMMISSION SYSTEM

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USE CASES Use case

is a narrative description in an outline form of the dialog that occurs between a primary and secondary system.

Continuous narrative format with each action numbered sequentially.

Ping-pong format consists of two narratives and the

numbering indicates how the tasks alternate between the primary and secondary systems.

Alternative events are actions that are not normally expected to occur; alphabetic letters are appended to step numbers.

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USE CASE

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USE CASE GUIDELINES

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PROJECT MANAGEMENTSteering committee

is a committee with the purpose of providing ongoing guidance, direction, and control of all systems projects.

MIS steering committee purpose is directing the use of the

firm’s computing resources. It establishes policies. It provides fiscal control. It resolves conflict.

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MANAGERS OF A SYSTEM LIFE CYCLE ARRANGED IN A HIERARCHY

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PROJECT LEADERSHIP

Project team includes all of the persons who participate

in the development of an information system.

Team leader (project leader) provides direction throughout the life of

the project.

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PROJECT MANAGEMENT MECHANISM Basis for project management is the

project plan. Gantt chart

is a horizontal bar chart that includes a bar for each task to be performed; bars arranged in time sequence.

Network diagram (CPM diagram, PERT chart) is a drawing that identifies activities and

links them with arrows to show the sequence in which they are to be performed.

Narrative reports are in the form of weekly written reports by project leader, communicates project information to MIS steering committee.

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A GANTT CHART

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A NETWORK DIAGRAM

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PROJECT COST ESTIMATING Cost-estimating inputs

Work breakdown structure (WBS) Resource requirements, resource rates Activity duration estimates Historical information

Cost-estimating tools and techniques Bottom-up estimating Computerized tools Mathematical models

Cost-estimating outputs Supporting details Cost-management plan

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COMPONENTS OF COST-ESTIMATING PROCESS

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EXAMPLE OF PROJECT COST