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Chapter 10:Chapter 10:Selecting the Best Alternative Selecting the Best Alternative

Design StrategyDesign Strategy

Object-Oriented Systems Analysis and Design

Joey F. George, Dinesh Batra,

Joseph S. Valacich, Jeffrey A. Hoffer

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Chapter ObjectivesChapter Objectives

After studying this chapter you should be able to:– Describe the different sources of

software.– Assemble the various pieces of an

alternative design strategy.– Generate at least three alternative design

strategies for an information system.

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Chapter Objectives Chapter Objectives (Continued)(Continued)

After studying this chapter you should be able to:– Select the best design strategy using

qualitative and quantitative methods.– Update a Baseline Project Plan (BPP)

based on the results of the analysis phase.

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Deliverables for Design Deliverables for Design Strategy SelectionStrategy Selection

Why three? One for high-functionality high-cost solution, one for minimum functionality low-cost solution, and one for middle-of-the-road

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Features are determined from requirements.

Constraints pertain to limitations on development efforts.

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Generating a Design StrategyGenerating a Design Strategy

Divide requirements (obtained during requirements gathering and structuring) into sets of capabilities, categorized by level of necessity

Enumerate different potential implementation environments (hardware and system software platforms)

Propose different sourcing possibilities for obtaining the necessary software

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What Is Outsourcing?What Is Outsourcing?

The practice of turning over responsibility of some or all of an organization’s information systems applications and operations to an outside firm

Can produce cost savings for the client, by leveraging the outsourcer’s economies of scale

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What Is an RFP?What Is an RFP?

Request for Proposal – a document provided to vendors to ask them to propose hardware and/or software products or services that will meet the requirements of an organization’s new information system

Based on vendor bids, analyst selects best candidates

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Main Sources of SoftwareMain Sources of Software

– Hardware Manufacturers– Prepackaged Software Producers– Custom Software Producers– Enterprise Solutions Software– In-house Development

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Hardware ManufacturersHardware Manufacturers

IBM is the leader in software sales and services

Hardware manufacturers tend to focus on system software and utilities

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Prepackaged SoftwarePrepackaged Software

Microsoft is the leader in prepackaged software production.

Prepackaged software is off-the-shelf software.

Often, prepackaged software is turnkey software (i.e., not customizable) .

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Many factors go into selection of off-the-shelf software, many of which are relevant for other software purchases.

Vendor support and viability are always among the most important criteria.

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Custom Software ProducersCustom Software Producers

Firms like Accenture and EDS are leading custom software producers.

Consulting firms that develop software to meet the client’s specific requirements

Consulting firms are usually called when the client company does not have in-house expertise or manpower available to develop the system.

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Enterprise Solutions SoftwareEnterprise Solutions Software

Enterprise Resource Planning (ERP) software – integrates individual traditional business functions modules enabling a single seamless transaction cut across functional boundaries

SAP AG is the leading vendor of ERP systems

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In-house DevelopmentIn-house Development

If sufficient system development expertise with the chosen platform exists in-house, then some or all of the system can be developed by the organization’s own staff

Often, there are a variety of sources that are used, with in-house staff playing a role as well as consultants or ERP vendors

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Validating Purchased Software Validating Purchased Software InformationInformation

Use a variety of information sources:– Vendor’s proposal– Running software through a series of tests– Feedback from other users of the vendor’s

product– Independent software testing services– Articles in trade publications

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Hardware and System Software Hardware and System Software IssuesIssues

Reasons to stay with old platform– Lower cost installation– Familiarity of IS staff– Ease of integration with existing applications– Less need for data and software conversions

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Hardware and System Software Hardware and System Software Issues (Continued)Issues (Continued)

Reasons to change to new platform– New components may not be compatible with

old platform– New platform provides opportunity for

organization to improve its technology holdings– New platform serves as impetus for significant

business process changes

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Example: Pine Valley FurnitureExample: Pine Valley Furniture

• System requirements categorized into mandatory, essential, and desired capabilities

• Constraints established

• Low-end, high-end, and moderate design strategies are generated

• Weighted approach used to compare alternative design strategies

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Application Server/Object Framework is the highest scoring alternative

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3-Tier architecture is scalable, and consists of a Web server providing the interface to the Internet in the 1st tier, an application server running the business rules of the application in the 2nd tier, and the corporate databases in the 3rd tier

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BPP goes through significant update as a result of design strategy generation and selection.

The System Description section is changed the most, and all sections are refined and altered.

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Cost-benefit analysis goes through significant update and revision after selecting a design strategy.

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Schedule estimation goes through significant update and revision after selecting a design strategy.

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RecapRecap

After studying this chapter we learned to:– Describe software sources.– Assemble design strategies.– Generate three alternative design strategies.– Select the best design strategy qualitatively and

quantitatively.– Update a baseline project plan.