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Harry S. Truman College

Harry S. Truman College. Prof. Mohammad Moizuddin Class CIS 250 Fall 2013. Systems Analysis and Design 10 th Edition. Chapter 4 Requirements Modeling. Chapter Objectives. Describe systems analysis phase activities

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Harry S. Truman College

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  1. Harry S. Truman College Prof. Mohammad Moizuddin Class CIS 250 Fall 2013

  2. Systems Analysis and Design 10th Edition Chapter 4 Requirements Modeling

  3. Chapter Objectives • Describe systems analysis phase activities • Explain joint application development (JAD), rapid application development (RAD), and agile methods • Use a functional decomposition diagram (FDD) to model business functions and processes • Describe the Unified Modeling Language (UML) and examples of UML diagrams

  4. Chapter Objectives (Cont.) • List and describe system requirements, including outputs, inputs, processes, performance, and controls • Explain the concept of scalability • Use fact-finding techniques, including interviews, documentation review, observation, questionnaires, sampling, and research • Define total cost of ownership (TCO) • Conduct a successful interview • Develop effective documentation methods to use during systems development

  5. Systems Analysis Phase Overview • Systems Analysis Phase Overview • Understand the proposed project • Ensure that it supports business requirements • Build a solid foundation for system development • Systems Analysis Activities • Requirements Modeling • Data and Process Modeling • Object Modeling • Development Strategies

  6. Systems Analysis Phase Overview (Cont.) • Requirements Modeling • Fact-finding to describe the current system • Requirements for new system • Data and Process Modeling • Graphically represent system data and processes • Object Modeling • Create objects to represent things, transactions and events • Development Strategies • Software trends, development alternatives, outsourcing, etc. FIGURE 4-2 The systems analysis phase consists of requirements modeling, data and process modeling, object modeling, and consideration of development strategies. Notice that the systems analysis tasks are interactive, even though the waterfall model generally depicts sequential development

  7. Systems Analysis Phase Overview (Cont.) • Systems Analysis Skills • Strong analytical skills • Interpersonal skills • Team-Based Techniques: JAD, RAD, and Agile Methods • Object is to deliver the best possible system at the lowest possible cost in the shortest possible time • Joint application development brings users into the design process • Rapid application development uses a condensed version of the system development life cycle • Agile methods stress intense interaction between developers and users

  8. Joint Application Development • Brings users into the development process as active participants • User Involvement (formally or informally) created a successful system • JAD Participants and Roles • Project leader and one or more members • Participants insulated from distractions of day-to-day operations

  9. Joint Application Development (Cont.) FIGURE 4-3 Typical JAD participants and roles

  10. Joint Application Development (Cont.) FIGURE 4-4 Typical agenda for a JAD session

  11. Joint Application Development (Cont.) JAD Disadvantages • JAD is more expensive than traditional methods • Can be cumbersome if group is too large JAD Advantages • JAD allows key users to participate effectively • Users more likely to feel a sense of ownership • Produces a more accurate statement of system requirements

  12. Rapid Application Development • Uses a group approach like JAD • JAD produces a requirements model, RAD produces a new system • Complete methodology • Four-phase life cycle that parallels the traditional SDLC • Reduces cost and development time • Increases the probability of success • Relies on prototyping and user involvement • Prototypes modified based on user input

  13. Rapid Application Development (Cont.) FIGURE 4-5 The four phases of the RAD model are requirements planning, user design, construction, and cutover. Notice the continuous interaction between the user design and construction phases RADPhases and Activities

  14. Rapid Application Development (Cont.) • Requirements Planning • Team agrees on business needs, project scope, constraints, and system requirements • Management authorization to continue is obtained • User Design • Users interact with analysts to develop models and prototypes • A combination of JAD and CASE tools are used • Users understand, modify, and approve a working model

  15. Rapid Application Development (Cont.) • Construction • Program and application development • Users can suggest changes as screens or reports are developed • Cutover • Includes data conversion, testing, changeover to the new system, and user training

  16. Rapid Application Development (Cont.) • RAD Objectives • Cut development time and expenses by involving users in every phase of systems development • Allow the development team to make necessary modifications quickly, as the design evolves • RAD Advantages • Systems developed more quickly with significant cost savings • RAD Disadvantages • Does not emphasize strategic business needs (system might work well in short term but miss long-term objectives) • Less time to develop quality, consistency, and design standards

  17. Agile Methods • Agile methods attempt to develop a system incrementally, by building a series of prototypes and constantly adjusting them to user requirements • Developers revise, extend, and merge earlier versions into the final product • Emphasizes continuous feedback, and each incremental step is affected by what was learned in the prior steps

  18. Agile Methods (Cont.) FIGURE 4-6 Agilian supports various modeling tools, such as the Unified Modeling Language, use cases, and business process modeling, among others

  19. Agile Methods (Cont.) • Scrum • A rugby term • Pigs include the product owner, the facilitator, and the development team • Chickens include users, other stakeholders, and managers • Scrum sessions have specific guidelines that emphasize time blocks, interaction, and team-based activities that result in deliverable software FIGURE 4-7 In a rugby scrum, team members prepare to lunge at each other to achieve their objectives

  20. Agile Methods (Cont.) • Agile Method Advantages and Disadvantages • Very flexible and efficient in dealing with change • Frequent deliverables constantly validate the project and reduce risk • Team members need a high level of technical and interpersonal skills • May be subject to significant change in scope

  21. Modeling Tools and Techniques • Involves graphical methods and nontechnical language that represent the system at various stages of development • Can use various tools • Functional Decomposition Diagrams • Functional decomposition diagram (FDD) • Model business functions and show how they are organized into lower-level processes

  22. Modeling Tools and Techniques (Cont.) • Functional Decomposition Diagrams • Top-down representation of a function or process • Similar to an organization chart FIGURE 4-8 This Visible Analyst FDD shows a library system with five top-level functions. The Library Operations function includes two additional levels of processes and sub processes

  23. Modeling Tools and Techniques (Cont.) • Business Process Modeling • Business process model (BPM) • Business process modeling notation (BPMN) • Pool • Swim lanes FIGURE 4-9 Using the Visible Analyst CASE tool, an analyst can create a business process diagram. The overall diagram is called a pool, and the two separate customer areas are called swim lanes

  24. Modeling Tools and Techniques (Cont.) • Data Flow Diagrams • Data flow diagram (DFD) • show how the system stores, processes, and transforms data • Additional levels of information and detail are depicted in other, related DFDs FIGURE 4-10 This Visible Analyst DFD shows how books are added and removed in a library system

  25. Modeling Tools and Techniques (Cont.) • Use Case Diagrams • Interaction betweenusers and the system FIGURE 4-12 This table documents the credit card validation use case shown in Figure 4-11 FIGURE 4-11 This Visible Analyst use case diagram shows a sales system, where the actor is a customer and the use case is a credit card validation

  26. Modeling Tools and Techniques (Cont.) • SequenceDiagrams • Shows the timingof interactions between objects as they occur FIGURE 4-14 This Visible Analyst sequence diagram shows a credit card validation process

  27. System Requirements Checklist • Output Examples • The Web site must report online volume statistics every four hours, and hourly during peak periods • The inventory system must produce a daily report showing the part number, description, quantity on hand, quantity allocated, quantity available, and unit cost of all sorted by part number • The contact management system must generate a daily reminder list for all sales reps • The purchasing system must provide suppliers with up-to-date specifications

  28. System Requirements Checklist (Cont.) • Input Examples • Manufacturing employees must swipe their ID cards into online data collection terminals that record labor costs and calculate production efficiency • The department head must enter overtime hours on a separate screen • Student grades must be entered on machine-scannable forms prepared by the instructor • Each input form must include date, time, product code, customer number, and quantity • Data entry screens must be uniform, except for background color, which can be changed by the user • A data entry person at the medical group must input patient services into the billing system

  29. System Requirements Checklist (Cont.) • Process Examples • The student records system must calculate the GPA at the end of each semester • As the final step in year-end processing, the payroll system must update employee salaries, bonuses, and benefits and produce tax data required by the IRS • The warehouse distribution system must analyze daily orders and create a routing pattern for delivery trucks that maximizes efficiency and reduces unnecessary mileage • The human resources system must interface properly with the existing payroll system • The equipment rental system must not execute new rental transactions for customers who have overdue accounts • The prescription system must automatically generate an insurance claim form

  30. System Requirements Checklist (Cont.) • Performance Examples • The system must support 25 users online simultaneously • Response time must not exceed four seconds • The system must be operational seven days a week, 365 days a year • The accounts receivable system must prepare customer statements by the third business day of the following month • The student records system must produce class lists within five hours after the end of registration • The online inventory control system must flag all low-stock items within one hour after the quantity falls below a predetermined minimum

  31. System Requirements Checklist (Cont.) • Control Examples • The system must provide logon security at the operating system level and at the application level • An employee record must be added, changed, or deleted only by a member of the human resources department • The system must maintain separate levels of security for users and the system administrator • All transactions must have audit trails • The manager of the sales department must approve orders that exceed a customer’s credit limit • The system must create an error log file that includes the error type, description, and time

  32. Future Growth, Costs, and Benefits • Scalability • A system’s ability to handle increased business volume and transactions in the future • A scalable system offers a better return on the initial investment • To evaluate scalability, you need information about projected future volume for all outputs, inputs, and processes

  33. Future Growth, Costs, and Benefits (Cont.) • Total Cost of Ownership • Total cost of ownership (TCO) is especially important if the development team is evaluating several alternatives • One problem is that cost estimates tend to understate indirect costs • Rapid Economic Justification (REJ) FIGURE 4-15 HP urges viewers to Take the TCO Challenge. Interested viewers can download a step-by-step TCO analysis that HP created

  34. Fact Finding • Fact-Finding Overview • First, you must identify the information you need • Develop a fact-finding plan • Who, What, Where, When, How, and Why? • Difference between asking what is being done and what could or should be done

  35. Fact Finding (Cont.) • Typical questions to ask • What business functions are supported by the current system? • What strategic objectives and business requirements must be supported by the new system? • What are the benefits and TCO of the proposed system? • What transactions will the system process? • What information do users and managers need from the system? • Must the new system interface with legacy systems?

  36. Fact Finding (Cont.) • Typical questions to ask • What procedures could be eliminated by business process reengineering? • What security issues exist? • What risks are acceptable? • What budget and timetable constraints will affect system development?

  37. Fact Finding (Cont.) • Who, What, Where, When, How, and Why? • Who performs each of the procedures within the system? Why? Are the correct people performing the activity? Could other people perform the tasks more effectively? • What is being done? What procedures are being followed? Why is that process necessary? Often, procedures are followed for many years and no one knows why. You should question why a procedure is being followed at all • Where are operations being performed? Why? Where could they be performed? Could they be performed more efficiently elsewhere? • When is a procedure performed? Why is it being performed at this time? Is this the best time? • How is a procedure performed? Why is it performed in that manner? Could it be performed better, more efficiently, or less expensively in some other manner?

  38. Fact Finding (Cont.) FIGURE 4-17 Sample questions during requirements modeling as the focus shifts from the current system to the proposed system

  39. Fact Finding (Cont.) • The Zachman Framework • Zachman Framework for Enterprise Architecture • Helps managers and users understand the model and assures that overall business goals translate into successful IT projects FIGURE 4-18 Visible Analyst uses the Zachman Framework for Enterprise Architecture. The Zachman concept presents traditional fact-finding questions in a systems development context

  40. Interviews • Step1.Determine the people to interview • Step 2. Establish objectives for the interview • Step 3. Develop interview questions • Step 4. Prepare for the interview • Step 5. Conduct the interview • Step 6. Document the interview • Step 7. Evaluate the interview

  41. Interviews (Cont.) • Step1: Determine the people to interview • Select the right people and ask the right questions • Don’t rely on just an organization chart • Decide on group and/or individual interviews • Step 2. Establish objectives for the interview • Determine the areas to be discussed • List the facts you need to gather • Upper management provides the big picture • Users can give you specific details

  42. Interviews (Cont.) • Step 3. Develop interview questions • Decide what to ask and how to phrase the question • The same question to different people - for comparison • Open ended questions encourage spontaneous and unstructured responses • What are users saying about the new system? • How is this task performed? • Close ended questions limit the response - used to verify facts • How many personal computers do you have in this department? • Do you review the reports before they are sent out? • Range of response questions limit the response – uses a scale • On a scale of 1 to 10, with 1 the lowest and 10 the highest, how effective was your training? • How would you rate the severity of the problem: low, medium, or high?

  43. Interviews (Cont.) • Step 4. Prepare for the interview • Careful preparation is essential because an interview is an important meeting and not just a casual chat • Limit the interview to no more than one hour • Verify time, place, length, and topics via e-mail • Ask the interviewee to have samples available

  44. Interviews (Cont.) FIGURE 4-20 Sample message to a department head about interviews

  45. Interviews (Cont.) FIGURE 4-21 Sample message to confirm an interview

  46. Interviews (Cont.) • Step 5. Conduct the interview • Develop a specific plan for the meeting • Begin by introducing yourself, describing the project, and explaining your interview objectives • Engaged listening • Allow the person enough time to think about the question • After an interview, you should summarize the session and seek a confirmation

  47. Interviews (Cont.) • Step 6. Document the interview • Note taking should be kept to a minimum • After conducting the interview, you must record the information quickly • After the interview, send memo to the interviewee expressing your appreciation • Note date, time, location, purpose of the interview, and the main points you discussed so the interviewee has a written summary and can offer additions or corrections

  48. Interviews (Cont.) • Step 7. Evaluate the interview • In addition to recording the facts obtained in an interview, try to identify any possible biases • Unsuccessful Interviews • No matter how well you prepare for interviews, some are not successful • Misunderstanding or personality conflict could affect the interview negatively, or the interviewee might be afraid that the new system will eliminate or change his or her job

  49. Other Fact-Finding Techniques • Document Review • Review old and current forms and documentation • Observation • Seeing the system in action gives you additional perspective and a better understanding of the system procedures • Plan your observations in advance • Consider the Hawthorne Effect Study • Productivity seemed to improve whenever workers knew they were being observed

  50. Other Fact-Finding Techniques (Cont.) • Questionnaires and Surveys • When designing a questionnaire, the most important rule of all is to make sure that your questions collect the right data in a form that you can use to further your fact-finding • Fill-in form FIGURE 4-23 Online version of a sample questionnaire. Does it follow the suggested guidelines?

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