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Systems Analysis

Systems Analysis. Lecture 5 Requirements Investigation and Analysis. BTEC HNC Systems Support Castle College 2007/8. 1. Lecture Objectives. Systems analysis phase activities The need for user involvement in requirements modeling

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Systems Analysis

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  1. Systems Analysis Lecture 5 Requirements Investigation and Analysis BTEC HNC Systems Support Castle College 2007/8 1

  2. Lecture Objectives • Systems analysis phase activities • The need for user involvement in requirements modeling • Explore the initial fact finding stage and the steps involved BTEC HNC Systems Support Castle College 2007/8 2

  3. BTEC HNC Systems Support Castle College 2007/8 3

  4. Systems Analysis Phase Major Activities Requirements Data and Process Modeling Modeling Development Strategies BTEC HNC Systems Support Castle College 2007/8 4

  5. Requirements Modeling To describe and identify the requirements of a new system we need to first gather the facts: • Required inputs/required outputs • Processes • Performance • Security BTEC HNC Systems Support Castle College 2007/8 5

  6. Definitions • Outputs refer to electronic or printed information produced by the system • Inputs refers to the necessary data that enters the system – either manually or in an automated manner • Processes refer to the logical rules that are applied to transform the data BTEC HNC Systems Support Castle College 2007/8 6

  7. Definitions (cont.) • Performance refers to system characteristics such as speed, volume, capacity, availability and reliability • Security refers to hardware, software and procedural controls that safeguard and protect a system and its data from both internal and external threats BTEC HNC Systems Support Castle College 2007/8 7

  8. Other areas to consider • Batch v Real Time • Basic Architecture • Backup and Recovery • User Support BTEC HNC Systems Support Castle College 2007/8 8

  9. Perform Fact finding Fact finding involves various techniques and may consume several hours, days or weeks Fact finding involves the following: • examining organisational charts, • conducting interviews, • reviewing documentation, • observing operations, and • conduct a user survey. BTEC HNC Systems Support Castle College 2007/8 9

  10. SQIRO One way to remember fact finding methods is the pneumonic ‘SQIRO’ • Sampling – (examination of results) • Questionnaires (conduct a survey) • Interviews (with key personnel) • Research (Reading) • Observation –(of operations performed) BTEC HNC Systems Support Castle College 2007/8 10

  11. Info gathering  model building Understandnewsystem’s: Questionnaires Procedures Interviews Develop requirements and models Constraints Sampling Observation Functions Research BTEC HNC Systems Support Castle College 2007/8 11

  12. Organisational Charts • An analyst will study an organisational chart in order to understand how the department(s) function • This means that you can identify those people you wish to interview • Organisational charts show formal reporting relationships between staff members BTEC HNC Systems Support Castle College 2007/8 12

  13. Conduct Interviews The interview process involves the following steps: • Determine the people to interview • Establish objectives for the Interview • Develop interview questions • Prepare for the interview • Conduct and then document the interview • Evaluate the interview BTEC HNC Systems Support Castle College 2007/8 13

  14. An interview is the primary method of obtaining information(Shelley et al p69) BTEC HNC Systems Support Castle College 2007/8 14

  15. Review Documentation • The analyst will also want to revue the current documentation • The documentation describes the processes and situation with/of the present system BTEC HNC Systems Support Castle College 2007/8 15

  16. Observe Operation Another fact finding method is to observe the current system in operation • This will show how workers carry out a particular task • It could include Sampling the inputs or outputs of the system BTEC HNC Systems Support Castle College 2007/8 16

  17. Conduct a user survey • Less time consuming than interviews • Information can be obtained from a larger group of users • Surveys involve a questionnaire (form that users complete) • Less expensive and can include a cross section of people BTEC HNC Systems Support Castle College 2007/8 17

  18. Evaluate Feasibility • Economic Feasibilities (Cost/benefit analysis; current cash flow) • Technical Feasibilities (Risk – new technology; lack of expertise) • Operational Feasibilities (Cultural) (Longstanding work procedures; Shift in power; Fear – change, technology, loss of employment, loss of control) BTEC HNC Systems Support Castle College 2007/8 18

  19. Evaluate Feasibility (cont.) • Schedule Feasibilities (Develop schedule; high risk – assumptions and estimates, end date) • Resource Feasibilities (Skilled team members at right time, computer resources, physical facilities, support staff) BTEC HNC Systems Support Castle College 2007/8 19

  20. 2 – Data Process Modeling • Data and process modeling continues the modeling process by representing graphically (or conceptually) data and processes • There are various methods for doing this, which we will learn about in later lectures and through practical case studies, e.g. Use case models, data flow diagrams, etc BTEC HNC Systems Support Castle College 2007/8 20

  21. 3 – Development Strategies This phase is concerned with software trends, acquisition and development alternatives for the new system “The development strategies phase, considers various development options and prepares for the transition to the Systems Design Phase of the SDLC” (paraphrased from Shelley et al p92) BTEC HNC Systems Support Castle College 2007/8 21

  22. Methodologies and Options • Also called Development strategies • During project planning, it is necessary to choose from a range of methods • Each methodology (development strategy) uses different techniques to achieve the objectives of the new system requirements BTEC HNC Systems Support Castle College 2007/8 22

  23. Methodology 1 – Structured Analysis • Often called the ‘Traditional method’ and used extensively in the early days of IT development • Structured Systems Analysis and Design Methodology (SSADM) • This methodology treats processes and data as separate entities • Techniques used include Data flow diagrams BTEC HNC Systems Support Castle College 2007/8 23

  24. Alternatives to ‘Traditional’ • IT professionals now recognise that successful systems must be USER ORIENTED • Users need to be involved formally or informally at every stage of the system development BTEC HNC Systems Support Castle College 2007/8 24

  25. Result: Team orientated methods and techniques “Top managers expect the IT Department to deliver the best possible information system at the lowest possible cost in the shortest possible time” (p93 Shelley et al) To fulfill these expectations many IT managers have tried to increase user participation BTEC HNC Systems Support Castle College 2007/8 25

  26. Activity Consider the 3 stages we have just examined: Write one or two sentences to explain what your stage is and what the analyst needs to do at that stage Requirements modeling – A students Data and Process modeling – B students Development strategies – C students BTEC HNC Systems Support Castle College 2007/8 26

  27. Defining the ‘Deliverable’ • System Requirements Document • This is an overall requirements definition for the new system • Project management • Is now needed to co-ordinate people, tasks, timetables and budgets BTEC HNC Systems Support Castle College 2007/8 27

  28. Requirements Specification(s) • Clear, professional, thorough • Easy to understand and follow • Use diagrams / charts where possible • From highest level, drill down to more detail • Within Project Vision • Include Recommendations BTEC HNC Systems Support Castle College 2007/8 28

  29. Project Management • The system requirements document provides the ‘blueprint’ of what is needed for the new system • The Project management team then decide upon the best methods to achieve these requirements • There are a number of Methodologies from which to choose BTEC HNC Systems Support Castle College 2007/8 29

  30. Present results and recommendations • The final task in the Preliminary investigation is to prepare a report for management and possibly deliver a presentation • This feedback includes an estimate of the costs and benefits of the proposals and recommendations • Good oral and written communications are essential at this stage… BTEC HNC Systems Support Castle College 2007/8 30

  31. Oral presentations are often required allowing for questions and answers BTEC HNC Systems Support Castle College 2007/8 31

  32. In Conclusion • Systems analysis phase activities • User involvement • Requirements modeling • Examined the steps in initial fact finding BTEC HNC Systems Support Castle College 2007/8 32

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