2. D. Delen MSIS 5653 – Advanced Systems Development Midterm Exam Statistics

3. CHAPTER 7: Determining System Requirements 1.1 MSIS 5653 Advanced Systems Development Dursun Delen, Ph.D. Department of Management Oklahoma State University

4. D. Delen MSIS 5653 – Advanced Systems Development Learning Objectives Learn the classical and modern approaches to Requirements Determination Describe options for designing and conducting interviews and develop a plan for conducting an interview to determine system requirements Design, distribute, and analyze questionnaires to determine system requirements Explain advantages and pitfalls of observing workers and analyzing business documents to determine requirements 7.3

5. D. Delen MSIS 5653 – Advanced Systems Development Learning Objectives Explain how computing can provide support for requirements determination (GSS) Learn about Joint Application Design (JAD) Use prototyping during requirements determination Select the appropriate methods to discover system requirements Apply requirements determination to Internet applications 7.4

6. D. Delen MSIS 5653 – Advanced Systems Development Determining System Requirements in SDLC

7. D. Delen MSIS 5653 – Advanced Systems Development Performing Requirements Determination Organizational needs derive the requirements Gather information on what system should do from many sources People Reports Forms Procedures 7.6

8. D. Delen MSIS 5653 – Advanced Systems Development Performing Requirements Determination Characteristics for gathering requirements Impertinence  Question everything Impartiality  Find the best organizational solution Relaxation of constraints Attention to detail Reframing  View the organization in new ways 7.7

9. D. Delen MSIS 5653 – Advanced Systems Development Deliverables and Outcomes Types of deliverables: Information collected from users Existing documents and files Computer-based information Understanding of organizational components  Business objective  Information needs  Rules of data processing  Key events with respect to changes on the data values 7.8

10. D. Delen MSIS 5653 – Advanced Systems Development Traditional Methods for Determining Requirements Interviewing and Listening Gather facts, opinions and speculations Observe body language and emotions Guidelines  Plan Checklist Appointment  Be neutral  Listen  Seek a diverse view 7.9

11. D. Delen MSIS 5653 – Advanced Systems Development Traditional Methods for Determining Requirements Interviewing (Continued) Interview Questions  Open-Ended No pre-specified answers  Close-Ended Respondent is asked to choose from a set of specified responses T/F, M/C, Rating, and Ranking Additional Guidelines  Do not phrase questions in ways that imply a wrong or right answer  Listen very carefully to what is being said  Type up notes within 48 hours  Do not set expectations about the new system  Seek a variety of perspectives 7.10

12. D. Delen MSIS 5653 – Advanced Systems Development Traditional Methods for Determining Requirements Administering Questionnaires More cost-effective than interviews Choosing respondents  Should be representative of all users  Types of sampling methods Convenient Random sample Purposeful sample Stratified sample Design  Mostly closed-ended questions  Can be administered over the phone or in person 7.11

13. D. Delen MSIS 5653 – Advanced Systems Development Traditional Methods for Determining Requirements Questionnaires vs. Interviews 7.12

14. D. Delen MSIS 5653 – Advanced Systems Development Traditional Methods for Determining Requirements Interviewing Groups Advantages  More effective use of time  Enables people to hear opinions of others and to agree or disagree Disadvantages  Difficulty in scheduling Nominal Group Technique  Facilitated process to support idea generation by groups  Individuals work alone to generate ideas which are pooled under guidance of a trained facilitator 7.13

15. D. Delen MSIS 5653 – Advanced Systems Development Traditional Methods for Determining Requirements Directly Observing Users Serves as a good method to supplement interviews Often difficult to obtain unbiased data  People often work differently when being observed  Time and motion study? 7.14

16. D. Delen MSIS 5653 – Advanced Systems Development Traditional Methods for Determining Requirements Analyzing Procedures and Other Documents Types of information to be discovered:  Problems with existing system  Opportunity to meet new need  Organizational direction  Names of key individuals  Values of organization  Special information processing circumstances  Reasons for current system design  Rules for processing data 7.15

17. D. Delen MSIS 5653 – Advanced Systems Development Traditional Methods for Determining Requirements Analyzing Procedures and Other Documents Four types of useful documents  Written work procedures Describes how a job is performed Includes data and information used and created in the process of performing the job or task  Business form Explicitly indicate data flow in or out of a system  Report Enables the analyst to work backwards from the report to the data that generated it  Description of current information system 7.16

18. D. Delen MSIS 5653 – Advanced Systems Development Example: Business Forms and Reports

19. D. Delen MSIS 5653 – Advanced Systems Development Modern Methods for Determining Requirements Joint Application Design (JAD) Brings together key users, managers and systems analysts Purpose: collect system requirements simultaneously from key people Conducted off-site Prototyping Repetitive process Rudimentary version of system is built Replaces or augments SDLC Goal: to develop concrete specifications for ultimate system 4.18

20. D. Delen MSIS 5653 – Advanced Systems Development Joint Application Design (JAD) Participants Session Leader Users Managers Sponsor Systems Analysts Scribe IS Staff 4.19

21. D. Delen MSIS 5653 – Advanced Systems Development Joint Application Design (JAD) End Result Documentation detailing existing system Features of proposed system CASE Tools During JAD Upper CASE tools are used Enables analysts to enter system models directly into CASE during the JAD session Screen designs and prototyping can be done during JAD and shown to users 4.20

22. D. Delen MSIS 5653 – Advanced Systems Development Joint Application Design (JAD) Supporting JAD with GSS Group support systems (GSS) can be used to enable more participation by group members in JAD Members type their answers into the computer All members of the group see what other members have been typing 7.21

23. D. Delen MSIS 5653 – Advanced Systems Development Prototyping Quickly converts requirements to working version of system Once the user sees requirements converted to system, will ask for modifications or will generate additional requests Most useful when: User requests are not clear Few users are involved in the system Designs are complex and require concrete form History of communication problems between analysts and users Tools are readily available to build prototype 7.22

24. D. Delen MSIS 5653 – Advanced Systems Development Prototyping Drawbacks Tendency to avoid formal documentation Difficult to adapt to more general user audience Sharing data with other systems is often not considered Systems Development Life Cycle (SDLC) checks are often bypassed 7.23

25. D. Delen MSIS 5653 – Advanced Systems Development Business Process Reengineering (BPR) Search for and implementation of radical change in business processes to achieve breakthrough improvements in products and services Goals Reorganize complete flow of data in major sections of an organization Eliminate unnecessary steps Combine steps Become more responsive to future change 7.24

26. D. Delen MSIS 5653 – Advanced Systems Development Business Process Reengineering (BPR) Identification of processes to reengineer Key business processes  Set of activities designed to produce specific output for a particular customer or market  Focused on customers and outcome  Same techniques are used as were used for requirements determination Disruptive technologies Technologies that enable the breaking of long-held business rules that inhibit organizations from making radical business changes >>> 7.25

27. D. Delen MSIS 5653 – Advanced Systems Development Business Process Reengineering (BPR) 7.26

28. D. Delen MSIS 5653 – Advanced Systems Development Summary Interviews Open-ended and close-ended questions Preparation is key Questionnaires Must be carefully designed Can contain close-ended as well as open-ended questions Other means of gather requirements Observing workers Analyzing business documents Joint Application Design (JAD) Prototyping Business Process Reengineering (BPR) 7.27

29. CHAPTER 8: Structuring Systems Requirements: Process Modeling 2.28

30. D. Delen MSIS 5653 – Advanced Systems Development Learning Objectives Understand the logical modeling of processes through studying data flow diagrams How to draw data flow diagrams using rules and guidelines How to decompose data flow diagrams into lower-level diagrams Balancing of data flow diagrams 8.2

31. D. Delen MSIS 5653 – Advanced Systems Development Learning Objectives Explain the differences among four types of DFDs: current physical, current logical, new physical and new logical Discuss the use of data flow diagrams as analysis tools Compare and contrast data flow diagrams with Oracle’s process modeling tool and with functional hierarchy diagrams Discuss process modeling for Internet applications 8.30

32. D. Delen MSIS 5653 – Advanced Systems Development 8.31 Requirement Structuring: Process Modeling in SDLC

33. D. Delen MSIS 5653 – Advanced Systems Development Process Modeling Graphically represent the processes that capture, manipulate, store and distribute data between a system and its environment and among system components Data flow diagrams (DFD) Graphically illustrate movement of data between external entities and the processes and data stores within a system 8.32

34. D. Delen MSIS 5653 – Advanced Systems Development Process Modeling Modeling a system’s process Utilize information gathered during requirements determination Structure of the data is also modeled in addition to the processes Deliverables and Outcomes Set of coherent, interrelated data flow diagrams >>> 8.33

35. D. Delen MSIS 5653 – Advanced Systems Development Process Modeling Deliverables and outcomes (Continued…) Context data flow diagram (DFD)  Scope of system DFDs of current system  Enables analysts to understand current system DFDs of new logical system  Technology independent  Show data flows, structure and functional requirements of new system Project dictionary and CASE repository 8.34

36. D. Delen MSIS 5653 – Advanced Systems Development Data Flow Diagramming Mechanics Four symbols are used… 8.35

37. D. Delen MSIS 5653 – Advanced Systems Development Data Flow Diagramming Mechanics Data Flow Depicts data that are in motion and moving as a unit from one place to another in the system. Drawn as an arrow Select a meaningful name to represent the data 8.36

38. D. Delen MSIS 5653 – Advanced Systems Development Data Flow Diagramming Mechanics Data Store Depicts data at rest May represent data in  File folder  Computer-based file  Notebook The name of the store as well as the number are recorded in between lines 8.37

39. D. Delen MSIS 5653 – Advanced Systems Development Data Flow Diagramming Mechanics Process Depicts work or action performed on data so that they are transformed, stored or distributed Number of process as well as name are recorded Name is a verb phrase 8.38

40. D. Delen MSIS 5653 – Advanced Systems Development Data Flow Diagramming Mechanics Source/Sink Depicts the origin and/or destination of the data Sometimes referred to as an external entity Drawn as a square symbol Name states what the external agent is Because they are external, many characteristics are not of interest to us  Interactions that occur between sources and sinks  What they do with the information internally  How to control or redesign them  How to provide them with direct access to data stores 8.39

41. D. Delen MSIS 5653 – Advanced Systems Development Data Flow Diagramming Definitions Context Diagram A data flow diagram (DFD) of the scope of an organizational system that shows the system boundaries, external entities that interact with the system and the major information flows between the entities and the system Level-0 Diagram A data flow diagram (DFD) that represents a system’s major processes, data flows and data stores at a high level of detail 8.40

42. D. Delen MSIS 5653 – Advanced Systems Development Developing DFDs: An Example Hoosier Burger’s automated food ordering system Context Diagram (Figure 8-4) contains no data stores Next step is to expand the context diagram to show the breakdown of processes (Figure 8-5) 8.41

43. D. Delen MSIS 5653 – Advanced Systems Development Figure 8-4 Context diagram of Hoosier Burger’s food ordering system 8.42

44. D. Delen MSIS 5653 – Advanced Systems Development Figure 8-5 Level-0 DFD of Hoosier Burger’s food ordering system 8.43

45. D. Delen MSIS 5653 – Advanced Systems Development Data Flow Diagramming Rules Basic rules that apply to all DFDs Inputs to a process are always different than outputs Objects always have a unique name  In order to keep the diagram uncluttered, you can repeat data stores and sources/sinks on a diagram 8.44

46. D. Delen MSIS 5653 – Advanced Systems Development Data Flow Diagramming Rules Process A.No process can have only outputs (a miracle) B.No process can have only inputs (black hole) C.A process has a verb phrase label Data Store D.Data cannot be moved directly from one store to another E.Data cannot move directly from an outside source to a data store F.Data cannot move directly from a data store to a data sink G.Data store has a noun phrase label 8.45

47. D. Delen MSIS 5653 – Advanced Systems Development Data Flow Diagramming Rules Source/Sink H.Data cannot move directly from a source to a sink I.A source/sink has a noun phrase label Data Flow J.A data flow has only one direction of flow between symbols K.A fork means that exactly the same data goes from a common location to two or more processes, data stores or sources/sinks Continues >>> 8.46

48. D. Delen MSIS 5653 – Advanced Systems Development Data Flow Diagramming Rules 8.47 Data Flow (Continued…) L.A join means that exactly the same data comes from any two or more different processes, data stores or sources/sinks to a common location M.A data flow cannot go directly back to the same process it leaves N.A data flow to a data store means update O.A data flow from a data store means retrieve or use P.A data flow has a noun phrase label

49. D. Delen MSIS 5653 – Advanced Systems Development Decomposition of DFDs Functional decomposition Iterative process of breaking the description of a system/process down into finer and finer detail Repetitive procedure that creates hierarchically related set of diagrams representing the system Lowest level is called a primitive DFD Level-N Diagrams A DFD that is the result of n nested decompositions of a series of sub-processes from a process on a level-0 diagram 8.48

50. D. Delen MSIS 5653 – Advanced Systems Development Figure 8-7: Level-1 DFD showing the decomposition of Process 1.0 from the Level-0 diagram for Hoosier Burger’s food ordering system 8.49 Process Numbering 0 1.0, 2.0, … 1.1, 1.2, … 1.1.1, 1.1.2, …

51. D. Delen MSIS 5653 – Advanced Systems Development Balancing DFDs When decomposing a DFD, you must conserve inputs to and outputs from a process at the next level of decomposition This is called balancing Example: Hoosier Burgers In Figure 8-4, notice that there is one input to the system, the customer order Three outputs:  Customer receipt  Food order  Management reports 8.50

52. D. Delen MSIS 5653 – Advanced Systems Development Balancing DFDs Example (Continued) Notice Figure 8-5. We have the same inputs and outputs No new inputs or outputs have been introduced We can say that the context diagram and level-0 DFD are balanced 8.51

53. D. Delen MSIS 5653 – Advanced Systems Development Balancing DFDs An unbalanced example Figure 8-10 In context diagram, we have one input to the system, A and one output, B Level-0 diagram has one additional data flow, C These DFDs are not balanced 8.52

54. D. Delen MSIS 5653 – Advanced Systems Development Figure 8-10 An unbalanced set of data flow diagrams (a) Context diagram, (b) Level-0 diagram 8.53 (a) (b)

55. D. Delen MSIS 5653 – Advanced Systems Development Balancing DFDs We can split a data flow into separate data flows on a lower level diagram 8.54 (a) (b)

56. D. Delen MSIS 5653 – Advanced Systems Development Balancing DFDs Balancing leads to four additional advanced rules 8.55

57. D. Delen MSIS 5653 – Advanced Systems Development Four Different Types of DFDs Current Physical Process label includes an identification of the technology (people or systems) used to process the data Data flows and data stores are labeled with the actual name of the physical media on which data flow or in which data are stored Current Logical Physical aspects of system are removed as much as possible Current system is reduced to data and processes that transform them 8.56

58. D. Delen MSIS 5653 – Advanced Systems Development Current Physical DFD HB Inventory Control System

59. D. Delen MSIS 5653 – Advanced Systems Development Current Logical DFD HB Inventory Control System

60. D. Delen MSIS 5653 – Advanced Systems Development Four Different Types of DFDS New Logical Includes additional functions Obsolete functions are removed Inefficient data flows are reorganized New Physical Represents the physical implementation of the new system 8.59

61. D. Delen MSIS 5653 – Advanced Systems Development New Logical DFD HB Inventory Control System

62. D. Delen MSIS 5653 – Advanced Systems Development DFD Development Process Main Steps Determine the processes by making a list of all relevant business activities. Create the context diagram, including all external entities and the major data flow to or from them. Create Level-0 Diagram by analyzing the major activities within the context process. Include the external entities and major data stores. Create a child diagram for each complex process on Level-0 Diagram. Include local data stores and detailed processes. Detailed data flow diagrams may be developed by Analyzing what happens to an input data flow from an external entity and what is necessary to create an output data flow to an external entity Examining the data flow to or from a data store

63. D. Delen MSIS 5653 – Advanced Systems Development Guidelines for Drawing DFDs 8.62 Completeness DFD must include all components necessary for the system Each component must be fully described in the project dictionary or CASE repository

64. D. Delen MSIS 5653 – Advanced Systems Development Guidelines for Drawing DFDs Consistency The extent to which information contained on one level of a set of nested DFDs is also included on other levels  Missing Level-0 diagram, missing and/or mismatched I/O Timing Time is not represented well on DFDs Best to draw DFDs as if the system has never started and will never stop. Iterative Development Analyst should expect to redraw diagram several times before reaching the closest approximation to the system being modeled 8.63

65. D. Delen MSIS 5653 – Advanced Systems Development Guidelines for Drawing DFDs Primitive DFDs Lowest logical level of decomposition Decision has to be made when to stop decomposition Rules for stopping decomposition  When each process has been reduced to a single decision, calculation or database operation  When each data store represents data about a single entity  When the system user does not care to see any more detail  >>> 8.64

66. D. Delen MSIS 5653 – Advanced Systems Development Guidelines for Drawing DFDs Rules for stopping decomposition (continued) When every data flow does not need to be split further to show that data are handled in various ways When you believe that you have shown each business form or transaction, on-line display and report as a single data flow When you believe that there is a separate process for each choice on all lowest-level menu options 8.65

67. D. Delen MSIS 5653 – Advanced Systems Development Using DFDs as Analysis Tools Gap Analysis The process of discovering discrepancies between two or more sets of data flow diagrams or discrepancies within a single DFD Simulation and/or Activity Based Costing Inefficiencies in a system can often be identified through DFDs 8.66

68. D. Delen MSIS 5653 – Advanced Systems Development Using DFDs in Business Process Reengineering Example: IBM Credit 8.67 As-Is Avg.: 6 Days

69. D. Delen MSIS 5653 – Advanced Systems Development Using DFDs in Business Process Reengineering Example: IBM Credit (Continued…) 8.68 To-Be Avg.: 4 Hrs

70. D. Delen MSIS 5653 – Advanced Systems Development Using DFDs in Business Process Reengineering Example: IBM Credit (Continued…) After the reengineering effort  IBM was able to process 100 times the number of transactions in the same amount of time 8.69

71. D. Delen MSIS 5653 – Advanced Systems Development Oracle’s Process Modeler and Functional Hierarchy Diagrams Process Modeler Unique to Oracle Similar to DFDs but outputs and methods differ in several ways. 8.70

72. D. Delen MSIS 5653 – Advanced Systems Development Oracle’s Process Modeler 8.71

73. D. Delen MSIS 5653 – Advanced Systems Development Oracle’s Process Modeler and Functional Hierarchy Diagrams Functional Hierarchy Diagrams 8.72  Picture of various tasks performed in a business and how they are hierarchically related  Similar to IDEF0 Function Diagrams  Does not include data flows

74. D. Delen MSIS 5653 – Advanced Systems Development Summary Data flow diagrams (DFD) Symbols Rules for creating Decomposition Balancing Four different kinds of DFDs Current Physical Current Logical New Logical New Physical DFDs for Analysis and BPR Oracle’s Process Modeler and Functional Hierarchy Diagrams 8.73

75. D. Delen MSIS 5653 – Advanced Systems Development Figure 8.26 – Page 273

76. D. Delen MSIS 5653 – Advanced Systems Development Figure 8.27 – Page 274 D1

77. D. Delen MSIS 5653 – Advanced Systems Development Problem and Exercises #1 Scenario: Retail clothing store in a mall 1.List all relevant sources/sinks, processes, data stores and data flows 2.Draw a context diagram 3.Draw a level-0 diagram

78. D. Delen MSIS 5653 – Advanced Systems Development Scenario: Retail clothing store in a mall Level-0 Diagram