1. Ondřej Přibyl L4: SAD Methodologies page 1 Lecture 4: System Analysis and Design Methodologies Telematics systems and their design Doc.Ing. Ondřej Přibyl, Ph.D. Department of applied mathematics Faculty of Transportation sciences, CTU

2. Ondřej Přibyl L4: SAD Methodologies page 2 Faculty of Transportation Sciences, CTU Telematics systems and their design Scope of this lecture Part I - Overview of methodologies Part II - Recommendation to ITS

3. Ondřej Přibyl L4: SAD Methodologies page 3 PART I Systems Development Methodologies

4. Ondřej Přibyl L4: SAD Methodologies page 4 Faculty of Transportation Sciences, CTU Telematics systems and their design Discussion What does actually mean the term „Methodology“?

5. Ondřej Přibyl L4: SAD Methodologies page 5 Faculty of Transportation Sciences, CTU Telematics systems and their design A methodology is a formalized approach to implementing the SDLC. The methodology will vary depending on whether the emphasis is on businesses processes or on the data that supports the business. Remember it has nothing to do with UML!

6. Ondřej Přibyl L4: SAD Methodologies page 6 Faculty of Transportation Sciences, CTU Telematics systems and their design Classification of Methodologies Process-centered Methodologies –the focus is on defining the activities associated with the system. –The concentration is on representing the system as a set of processes with information flowing into and out of the processes. Data-centered Methodologies –focuses on defining the content of the data storage containers and how they are organized. –Data-centered methodologies utilize data models as the core of the system. Object-oriented Methodologies –balances the focus between processes and data. –The Unified Modeling Language (UML) is used to describe the system as a collection of objects incorporating both data and processes.

7. Ondřej Přibyl L4: SAD Methodologies page 7 Overview of System Development Methodologies

8. Ondřej Přibyl L4: SAD Methodologies page 8 Category I of the System Development Methodology: Structured Design Adopts a formal step-by-step approach to the SDLC that moves logically from one phase to the next. Introduces the use of formal modeling or diagramming techniques to describe a system ’ s basic business processes and follows a basic approach of two structured design categories.

9. Ondřej Přibyl L4: SAD Methodologies page 9 Waterfall Development

10. Ondřej Přibyl L4: SAD Methodologies page 10 Faculty of Transportation Sciences, CTU Telematics systems and their design Waterfall Development With waterfall development- based methodologies, the analysts and users proceed sequentially from one phase to the next.

11. Ondřej Přibyl L4: SAD Methodologies page 11 Faculty of Transportation Sciences, CTU Telematics systems and their design Waterfall Development Advantages: –The system requirements are identified long before programming begins. –Changes to the requirements are minimized as the project proceeds. Disadvantages: –The design must be completely specified before programming begins. –A long time elapses between the completion of the system proposal in the analysis phase and the delivery of the system.

12. Ondřej Přibyl L4: SAD Methodologies page 12 Parallel Development This methodology attempts to address the long time interval between the analysis phase and the delivery of the system in case of a waterfall model.

13. Ondřej Přibyl L4: SAD Methodologies page 13 Faculty of Transportation Sciences, CTU Telematics systems and their design Parallel Development

14. Ondřej Přibyl L4: SAD Methodologies page 14 Category II of the System Development Methodology: Rapid Application Development (RAD) This methodology breaks the overall system into a series of versions that are developed sequentially.

15. Ondřej Přibyl L4: SAD Methodologies page 15 Faculty of Transportation Sciences, CTU Telematics systems and their design Rapid Application Development (RAD) RAD-based methodologies adjust the SDLC phases to get some part of system developed quickly and into the hands of the users. A system development strategy that emphasizes speed of development through extensive user involvement in the rapid, iterative, and incremental construction of series of functioning prototypes of a system that eventually evolves into the final system. One possible subtle problem (disadvantage) with RAD-based methodologies is managing user expectations. –Prototype – a small-scale, representative, or working model of the users’ requirements or a proposed design for an information system. –Time box – the imposition of a nonextendable period of time, usually 60- 90 days, by which the first (or next) version of a system must be delivered into operation.

16. Ondřej Přibyl L4: SAD Methodologies page 16 Faculty of Transportation Sciences, CTU Telematics systems and their design Rapid Application Development focuses on building applications in a very short amount of time; traditionally with compromises in usability, features and/or execution speed. generically describes applications that can be designed and developed within 60-90 days.

17. Ondřej Přibyl L4: SAD Methodologies page 17 Faculty of Transportation Sciences, CTU Telematics systems and their design Rapid Application Development Strategy

18. Ondřej Přibyl L4: SAD Methodologies page 18 Phased Development

19. Ondřej Přibyl L4: SAD Methodologies page 19 Faculty of Transportation Sciences, CTU Telematics systems and their design Phased development The team categorizes the requirements into a series of versions, then the most important and fundamental requirements are bundled into the first version of the system. The analysis phase then leads into design and implementation; however, only with the set of requirements identified for version 1. As each version is completed, the team begins work on a new version.

20. Ondřej Přibyl L4: SAD Methodologies page 20 Faculty of Transportation Sciences, CTU Telematics systems and their design Phased development

21. Ondřej Přibyl L4: SAD Methodologies page 21 A prototype is a smaller version of the system with a minimal amount of features. Prototyping-based methodologies perform the analysis, design and implementation phases concurrently. All three phases are performed repeatedly in a cycle until the system is completed. Prototyping-based Methodology

22. Ondřej Přibyl L4: SAD Methodologies page 22 Faculty of Transportation Sciences, CTU Telematics systems and their design Prototyping-based Methodology

23. Ondřej Přibyl L4: SAD Methodologies page 23 Faculty of Transportation Sciences, CTU Telematics systems and their design Prototyping-based Methodology Advantage: –Provides a system for the users to interact with, even if it is not initially ready for use. –Helps to capture real user requirements Disadvantage: –Often the prototype undergoes such significant changes that many initial design decisions prove to be poor ones.

24. Ondřej Přibyl L4: SAD Methodologies page 24 Throwaway Prototyping-based Methodology

25. Ondřej Přibyl L4: SAD Methodologies page 25 Faculty of Transportation Sciences, CTU Telematics systems and their design Throwaway Prototyping-based Methodology Throwaway prototyping methodologies are similar to prototyping based methodologies. The main difference is that throwaway prototyping IS completed during a different point in the SDLC. Has relatively thorough analysis phase.

26. Ondřej Přibyl L4: SAD Methodologies page 26 Faculty of Transportation Sciences, CTU Telematics systems and their design Throwaway Prototyping-based Methodology Throwaway or Rapid Prototyping refers to the creation of a model that will eventually be discarded rather than becoming part of the final software. After preliminary requirements gathering, a simple working model of the system is constructed to visually show the users what their requirements may look like when they are implemented into a finished system. Advatages –it can be done quickly. If the users can get quick feedback on their requirements, they may be able to refine them early in the development of the software. –ability to construct interfaces that the users can test.

27. Ondřej Přibyl L4: SAD Methodologies page 27 Category III of the System Development Methodology: Agile Development Focuses on streamlining the SDLC by eliminating much of the modeling and documentation overhead and the time spent on those tasks. Projects emphasize simple, iterative application development.

28. Ondřej Přibyl L4: SAD Methodologies page 28 Faculty of Transportation Sciences, CTU Telematics systems and their design Agile Methods Agile methods have much in common with the Rapid Application DevelopmentRapid Application Development Agile methods break tasks into small increments with minimal planning and do not directly involve long-term planning. Iterations are short time frames that typically last from one to four weeks. Each iteration involves a cross functional team working in all functions: –planning, requirements analysis, design, coding, unit testing, and acceptance testing.requirements analysisdesigncodingunit testingacceptance testing At the end of the iteration a working product is demonstrated to stakeholders. This minimizes overall risk and allows the project to adapt to changes quickly.

29. Ondřej Přibyl L4: SAD Methodologies page 29 Faculty of Transportation Sciences, CTU Telematics systems and their design http://commons.wikimedia.org/wiki/File:Agile_Sof tware_Development_methodology.jpg

30. Ondřej Přibyl L4: SAD Methodologies page 30 An Extreme Programming-based Methodology

31. Ondřej Přibyl L4: SAD Methodologies page 31 Faculty of Transportation Sciences, CTU Telematics systems and their design eXtreme Programming (XP) was founded on four core values: –Communication –Simplicity –Feedback –Courage Key principles of XP include: –Continuous testing –Simple coding –Close interaction with the end users to build systems very quickly –Smaller development teams An Extreme Programming-based Methodology

32. Ondřej Přibyl L4: SAD Methodologies page 32 Faculty of Transportation Sciences, CTU Telematics systems and their design An Extreme Programming-based Methodology

33. Ondřej Přibyl L4: SAD Methodologies page 33 Faculty of Transportation Sciences, CTU Telematics systems and their design SCRUM (Agile development) 33 Source: www.redletterday.ch

34. Ondřej Přibyl L4: SAD Methodologies page 34 Faculty of Transportation Sciences, CTU Telematics systems and their design Challenges of Agile methods can be inefficient in large organizations and certain types of projects Agile methods seem best for developmental and non-sequential projects Many organizations believe that agile methodologies are too extreme and adopt a hybrid approach that mixes elements of agile and plan-driven approaches It is all about communication!

35. Ondřej Přibyl L4: SAD Methodologies page 35 Selecting the Appropriate Development Methodology

36. Ondřej Přibyl L4: SAD Methodologies page 36 Faculty of Transportation Sciences, CTU Telematics systems and their design Selecting of methodology Selecting a methodology is not simple, as no one methodology is always best. Many organizations have their own standards. The next figure summarizes some important methodology selection criteria.

37. Ondřej Přibyl L4: SAD Methodologies page 37 Faculty of Transportation Sciences, CTU Telematics systems and their design Criteria for Selecting a Methodology

38. Ondřej Přibyl L4: SAD Methodologies page 38 Faculty of Transportation Sciences, CTU Telematics systems and their design Clarity of User Requirements RAD methodologies of prototyping and throwaway prototyping are usually more appropriate when user requirements are unclear as they provide prototypes for users to interact with early in the SDLC.

39. Ondřej Přibyl L4: SAD Methodologies page 39 Faculty of Transportation Sciences, CTU Telematics systems and their design Familiarity with Technology If the system is designed without some familiarity with the base technology, risks increase because the tools may not be capable of doing what is needed.

40. Ondřej Přibyl L4: SAD Methodologies page 40 Faculty of Transportation Sciences, CTU Telematics systems and their design System Complexity Complex systems require careful and detailed analysis and design. Project teams who follow phased development-based methodologies tend to devote less attention to the analysis of the complete problem domain than they might if they were using other methodologies.

41. Ondřej Přibyl L4: SAD Methodologies page 41 Faculty of Transportation Sciences, CTU Telematics systems and their design System Reliability System reliability is usually an important factor in system development. Throwaway prototyping-based methodologies are most appropriate when system reliability is a high priority. Prototyping-based methodologies are generally not a good choice as they lack careful analysis and design phases.

42. Ondřej Přibyl L4: SAD Methodologies page 42 Faculty of Transportation Sciences, CTU Telematics systems and their design Short Time Schedules RAD-based methodologies are well suited for projects with short time schedules as they increase speed. Waterfall-based methodologies are the worst choice when time is essential as they do not allow for easy schedule changes.

43. Ondřej Přibyl L4: SAD Methodologies page 43 Faculty of Transportation Sciences, CTU Telematics systems and their design RAD-based methodologies move many of the critical design decisions earlier in the project; consequently, this helps project managers recognize and address risk factors and keep expectations high. Schedule Visibility

44. Ondřej Přibyl L4: SAD Methodologies page 44 Faculty of Transportation Sciences, CTU Telematics systems and their design IT Project success Rate (Chaos report) As the methodology and project management in IT projects improves, the success rate grows How is it affected by selected methodology?

45. Ondřej Přibyl L4: SAD Methodologies page 45 Faculty of Transportation Sciences, CTU Telematics systems and their design Project success rates Source: Dr. Dobbs IT Survey 2010 http://www.ddj.com/security/226500046http://www.ddj.com/security/226500046

46. Ondřej Přibyl L4: SAD Methodologies page 46 Faculty of Transportation Sciences, CTU Telematics systems and their design Agile projects are 3 times more successful http://www.controlchaos.com/storage/S3D%20First%20Chapter.pdf

47. Ondřej Přibyl L4: SAD Methodologies page 47 Faculty of Transportation Sciences, CTU Telematics systems and their design Effectiveness of development Paradigms

48. Ondřej Přibyl L4: SAD Methodologies page 48 PART II Methodology recommended for ITS 1.SEMP Framework (FHWA for ITS) 2.Methodology to design ITS (CZ)

49. Ondřej Přibyl L4: SAD Methodologies page 49 Faculty of Transportation Sciences, CTU Telematics systems and their design SEMP Framework (http://www.fhwa.dot.gov/cadiv/segb/index.htm)

50. Ondřej Přibyl L4: SAD Methodologies page 50 Faculty of Transportation Sciences, CTU Telematics systems and their design 1. System Engineering Management Plan (SEMP)

51. Ondřej Přibyl L4: SAD Methodologies page 51 Faculty of Transportation Sciences, CTU Telematics systems and their design 1. System Engineering Process – Main features –Based on common Vee development model Consists of the following major phases: » System decomposition (Step 1 – 5) » System implementation (Step 6) » System composition (Step 7 – 10) » System operation (Step 11) –Unified Modeling Language (UML) is used to cover the steps in the model (concept, requirements design, test cases, etc.) –Defines –Major steps, –Deliverables, and –Responsibilities.

52. Ondřej Přibyl L4: SAD Methodologies page 52 Faculty of Transportation Sciences, CTU Telematics systems and their design Described in “ Methodology to design ITS ” (CTU, In Czech, 2009) Based on SSADM (Structured System Analysis and Design Methodology) –Analysis of the current system Feasibility stage –Outline business specification Concept preparation –Detailed business specification Requirements specification stage –Logical data design In this stage, technically feasible options are described –Logical process design logical designs and processes are updated –Physical design to specify the physical data and process design 2. Methodology recommended for ITS Systems

53. Ondřej Přibyl L4: SAD Methodologies page 53 Faculty of Transportation Sciences, CTU Telematics systems and their design ITS process – an overview Part 1 Part 2 Part 3 Part 4 Part 5

54. Ondřej Přibyl L4: SAD Methodologies page 54 Faculty of Transportation Sciences, CTU Telematics systems and their design Analysis and Design of ITS Systems (Part 1) System concept –Based on ITS architecture –Includes current state analysis –Includes definition of objectives Define actors –See lecture notes Define User needs –RFP and other user documents –Based on ITS architecture –Based on system concept

55. Ondřej Přibyl L4: SAD Methodologies page 55 Faculty of Transportation Sciences, CTU Telematics systems and their design Analysis and Design of ITS Systems (Part 2) System Requirements Specification (SRS) –Based on user needs –Based on standards –Based on state of the art know-how

56. Ondřej Přibyl L4: SAD Methodologies page 56 Faculty of Transportation Sciences, CTU Telematics systems and their design Analysis and Design of ITS Systems (Part 3) Use case diagram Behavior description / processes –Textual process / Activity diagram / interaction diagram

57. Ondřej Přibyl L4: SAD Methodologies page 57 Faculty of Transportation Sciences, CTU Telematics systems and their design Analysis and Design of ITS Systems (Part 4) Physical model –HW components –Interactions among components –Communication architecture –Interface specification –Assignement of functions (use cases) to HW Data model (Structures) –ER Model

58. Ondřej Přibyl L4: SAD Methodologies page 58 Faculty of Transportation Sciences, CTU Telematics systems and their design Analysis and Design of ITS Systems (Part 5)

59. Ondřej Přibyl L4: SAD Methodologies page 59 Faculty of Transportation Sciences, CTU Telematics systems and their design Summary of major steps and deliverables 1.Preparing system concept 2.Requirement analysis –Specify User needs –Define Requirements on the system 3.Functionality analysis –Define actors in the system –Define use cases and assign them to particular actors –Define exact functionality for each use case 4.Data model Creating of an entity-relationship (E-R) model Definition of all tables and their relationships 5.Component design/physical design Major physical components Assignment of functions (use cases) to physical components Interface definition System concept Requirements specification Functional architecture Physical architecture Database design