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IS 421 Information Systems Analysis James Nowotarski 4 November 2002.

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Presentation on theme: "IS 421 Information Systems Analysis James Nowotarski 4 November 2002."— Presentation transcript:

1 IS 421 Information Systems Analysis James Nowotarski 4 November 2002

2 Recap data flow diagramming Understand steps required for creating a work plan Discuss Assignment 5 Today’s Objectives

3 Course Map Contents 1. Introduction Planning Phase 2. Project Initiation 3. Project Management Analysis Phase 4. Systems Analysis 5. Gathering Information 6. Process Modeling 7. Data Modeling 1234678910115 Assignments Quizzes Final Week Core Exam Review

4 Topic Duration Prof. Burns30 minutes DFD Recap30 minutes Quiz45 minutes *** Break15 minutes Project management45 minutes Assignment 5 Intro15 minutes Today’s agenda

5 Topic Duration Prof. Burns30 minutes DFD Recap30 minutes Quiz45 minutes *** Break15 minutes Project management45 minutes Assignment 5 Intro15 minutes Today’s agenda

6 Process modeling Prepare use cases use case reports Create DFDs Users data flow diagrams business process info Easier for users to work with than DFDs Info gathered through interviews, JAD, etc. To Design

7 DFD Balancing 0 System Name Input A Entity 1 Entity 2 Input B Output C Entity 3

8 DFD Balancing Input A 1 General Process AAA Entity 1 Entity 2 Output C Entity 3 Input B 3 General Process CCC 2 General Process BBB 4 General Process DDD Data Flow B D1 Data Store 1 D2 Data Store 2 Data Flow D Data Flow A Data Flow C

9 Which is best? Customer Change address 1 Address change info D1 Customer Information Address change info Customer Change address 1 Address change info D1 Customer Information Address change info Customer Change address 1 Address info D1 Customer Information Address change info Scenario: A customer notifies a magazine publisher of a change of address. “For clarity, it is better practice to draw two separate data flows” (p. 149)

10 Manual vs. Automated processes Chronological order Can same external entity be shown more than once (yes, to avoid crossing lines) DFD Issues

11 DFD Step-by-Step (8) Grades are reported back to students via a course web page created from the spreadsheet.

12 Topic Duration Prof. Burns30 minutes DFD Recap30 minutes Quiz45 minutes *** Break15 minutes Project management45 minutes Assignment 5 Intro15 minutes Today’s agenda

13 Topic Duration Prof. Burns30 minutes DFD Recap30 minutes Quiz45 minutes *** Break15 minutes Project management45 minutes Assignment 5 Intro15 minutes Today’s agenda

14 Project Management

15 Key Definitions Project management is the process of planning and controlling the development of a system within a specified timeframe at a minimum cost with the right functionality.

16 Management Challenges in Analysis Political difficulties –Especially in larger projects, where the new system will serve several, possibly conflicting, interest groups Communication problems –People of different backgrounds, vocabularies being asked to work together –Users in particular may struggle to understand the technical-looking outputs of the Analysis phase Scope management Analysis paralysis –Easy to become mired in detail, not know when to finish “Prematurely physical”

17 Project Management (50K foot view) Create Work plan Staff the project Control project work

18 Create the work plan Users requirements 1 Negotiate reqts negotiated requirements 2 Decom- pose work breakdown structure 4 Estimate resources workmonths 3 Estimate size deliverable size 5 Develop schedule Iterate as necessary

19 Estimating a Project Based on Industry Information Planning Analysis Design Implementation Industry Standard For Web15% 20% 35% 30% Applications Time Required 4 5.33 9.33 8 in Person Months

20 Some Courses at DePaul SE 468: Software Measurement and Estimation –Software metrics. Productivity, effort and defect models. Software cost estimation. PREREQUISTE(S):CSC 423 and either SE 430 or CSC 315 or consent SE 477: Software and System Project Management –Planning, controlling, organizing, staffing and directing software development activities or information systems projects. Theories, techniques and tools for scheduling, feasibility study, cost-benefit analysis. Measurement and evaluation of quality and productivity. PREREQUISTE(S):SE 465 or CSC 315

21 Estimation Trade-offs Time –Months Effort –Person-months Size –Function points –Lines of code

22 Getting the Right Numbers for Estimation Prior projects –Past experience –Industry standards Detailed analysis

23 Estimating Schedule Time Rule of thumb for estimation Schedule Time (months) = 3.0 * person-months 1/3

24 Timeboxing Fixed deadline Reduced functionality, if necessary Fewer “finishing touches”

25 Timeboxing Steps Set delivery date –Deadline should not be impossible –Should be set by development group Prioritize features by importance Build the system core Postpone unfinished functionality Deliver the system with core functionality Repeat steps 3-5 to add refinements and enhancements

26 Margins of Error in Cost and Time Estimates Typical margins of Error for Well-done Estimates PhaseDeliverableCost (%)time (%) PlanningSystem Request40060 Project Plan10025 AnalysisSystem Proposal5015 DesignSystem Specification2510 Source: Boehm et al. (1995)

27 Relative Cost to Fix an Error It costs 50x more to fix an error discovered in production than in Analysis phase Phase in which error detected AnalysisDesignCodeUnit testAcceptance test Production 0.1 0.2 0.5 1 2 5 10 20 50 Relative cost to fix

28 Tracking Tasks Using Gantt Chart Action Week 2 3 4 5 6 7 8 9 10 11 12 13

29 CASE Tools Initiation Analysis Design Implementation Upper CASELower CASE Integrated CASE (I-CASE)

30 Procedural Metadata Logic DiagramsScreen Designs CASE Repository CASE Components

31 Standards Examples –Formal rules for naming files –Forms indicating goals reached (see page 75) –Programming guidelines

32 Documentation Project binder Table of contents Continual updating

33 Classic Mistakes Overly optimistic schedule Failing to monitor schedule Failing to update schedule Adding people to a late project Scope creep Lack of change control

34 Topic Duration Prof. Burns30 minutes DFD Recap30 minutes Quiz45 minutes *** Break15 minutes Project management45 minutes Assignment 5 Intro15 minutes Today’s agenda

35 End of slides


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