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CHAPTER 8

CHAPTER 8. Decision Support Systems Development. 8.1 DSS Development Issues. How to develop a DSS DSS must usually be custom tailored The application are diverse, ranging from data-oriented DSS to model-oriented DSS in different functional areas The vendors assisted in the DSS Construction

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CHAPTER 8

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  1. CHAPTER 8 Decision Support Systems Development

  2. 8.1 DSS Development Issues • How to develop a DSS • DSS must usually be custom tailored • The application are diverse, ranging from data-oriented DSS to model-oriented DSS in different functional areas • The vendors assisted in the DSS Construction • Hardware, networking, man-machine interface and potential impact of DSS on the individual and groups. Software problem focused in this chapter • Other problem are: All Right Reserved, Zhong YAO, School of E&M, BHU

  3. 8.1 DSS Development Issues • System development life cycle (SDLC) • Prototyping • Objective-Oriented Developing Method • ROMC • Organizing and forming the development team • Complex process • Technical issues • Behavioral issues • Different approaches All Right Reserved, Zhong YAO, School of E&M, BHU

  4. 8.1 DSS Development Landscape and Framework All Right Reserved, Zhong YAO, School of E&M, BHU

  5. 8.2 DSS Development Platform • General-purpose programming language, such as COBOL or PASCAL. Little has been used in 1990s • Fourth-generation language (4GL), like a SQL. • OLAP with a data warehouse or large database • DSS integrated development tool (generator, engine), such as Excel, Lotus Domino. • Domain-specific DSS generator, such SAS, MAPLE, now Mathmatica, Matlab. • Use the CASE methodology • Integrate several of the above All Right Reserved, Zhong YAO, School of E&M, BHU

  6. 8.2 DSS Development Classification • In-house Development (Insourcing) • System Development Lifecycle (SDLC) • Rapid Application Development (RAD) • Prototyping • Buying Applications • Leasing Applications • Software-as-a-Service • Outsourcing Development Options • Outsourcing • Application Service Providers (ASP) • On-Demand Computing All Right Reserved, Zhong YAO, School of E&M, BHU

  7. 8.3 Traditional Systems Development Life Cycle (SDLC) (Waterfall) Need Planning Analysis Design Implementation System All Right Reserved, Zhong YAO, School of E&M, BHU

  8. 8.3 Traditional Systems Development Life Cycle (SDLC) • Phase A-Planning, • Phase B-Research, • Phase C-System Analysis and Conceptual Design, • Phase D-Design, • Phase E-Construction, • Phase F-Implementation, • Phase G-Maintenance and Documentation, • Phase H-Adaptation • Simplifying Into Four Phases: • Planning (Phase A, and Phase B) • Analysis (Phase C) • Design (Phase C , D, and E) • Implementation (Phase F, G, and H) All Right Reserved, Zhong YAO, School of E&M, BHU

  9. 8.3 Traditional Systems Development Life Cycle (SDLC) • Planning - Why Build the System? Minor Step Deliverable 1. Identify business value System request 2. Analyze feasibility Feasibility study 3. Develop work plan Work plan 4. Staff project Staffing plan, Project charter 5. Control and direct project Project management tools CASE tool Standards list Project binders / files Risk assessment All Right Reserved, Zhong YAO, School of E&M, BHU

  10. 8.3 Traditional Systems Development Life Cycle (SDLC) • Analysis- Who, What, When, Where? Minor Step Deliverable 6. Analyze problem Analysis plan 7. Gather information Information 8. Model process(es) Process model 9. Model data Data model All Right Reserved, Zhong YAO, School of E&M, BHU

  11. 8.3 Traditional Systems Development Life Cycle (SDLC) • Design - How Will the System Work? Minor Step Deliverable 10. Design physical system Design plan 11. Design architecture Architecture design, Infrastructure design 12. Design interface Interface design 13. Design database and files Data storage design 14. Design program(s) Program design All Right Reserved, Zhong YAO, School of E&M, BHU

  12. 8.3 Traditional Systems Development Life Cycle (SDLC) • Implementation--- System Delivery Minor Step Deliverable 15. Construction Test plan, Programs, Documentation 16. Installation Conversion plan, Training plan All Right Reserved, Zhong YAO, School of E&M, BHU

  13. 8.3 Traditional Systems Development Life Cycle (SDLC) • Common Implementation Headaches • No project team or management support • Hazy purpose; no defined schedule; ballooning scope • Unclear aspects of make vs. buy decisions • Few project integrations are functional out of the box • Qualitative benefits • No user buy in • Poor project management skills • No accountability (责任) / no responsibility All Right Reserved, Zhong YAO, School of E&M, BHU

  14. 8.3 Traditional Systems Development Life Cycle (SDLC) • CASE Tools Functions • Information systems for systems analysts • Can help manage system development • Upper CASE (assists in analysis) • Lower CASE (manages diagrams and code generation) • Integrated CASE (both) • Often used tools: • Oracle Enterprise Development Suite • Rational Rose • Paradigm Plus • Visible Analyst • Logic Works Suite • AxiomSys and AxiomDsn • V32 & X32 • Visual Studio All Right Reserved, Zhong YAO, School of E&M, BHU

  15. 8.3 Traditional Systems Development Life Cycle (SDLC) • Project Management (PM) • Team leader must have good PM skills • Major reason for IS development failures-bad PM skills • Only 26% of all projects surveyed (23,000) in 1998 succeeded • 28% failed, 46% challenged • Lower success rates for large companies • Better PM skills needed • Skills for Project Managers • Technology and business knowledge • Judgment • Negotiation All Right Reserved, Zhong YAO, School of E&M, BHU

  16. 8.3 Traditional Systems Development Life Cycle (SDLC) • Good communication • Organization • Implementation Failures (DW Example) • No user involvement • No clear objectives stated early • No real executive sponsorship • Not appropriate for the DSS development All Right Reserved, Zhong YAO, School of E&M, BHU

  17. 8.4 Alternative Development Methodologies • Parallel development • Rapid application development (RAD) methodologies • Phased development • Prototyping • Throwaway prototyping All Right Reserved, Zhong YAO, School of E&M, BHU

  18. 8.4 Alternative Development Methodologies • Parallel Development • Multiple copies of design and implementation phases • To develop separate subsystems • All come together in a single implementation phase • Phased Development • Break system up into versions developed sequentially • Each version has more functionality • Evolves into a final system • Users gain functionality quickly • But initial systems are incomplete All Right Reserved, Zhong YAO, School of E&M, BHU

  19. 8.4 Alternative Development Methodologies • Prototyping (also called Evolutionary Prototyping Process, iterative process, middle-out process, adaptive design, incremental design) Characteristics: • Performing analysis, design, and implementation phases concurrently, and repeatedly • Users see system functionality quickly and provide feedback • Decision maker learns about problem • But can lose gains in repetition • Aims: building a DSS in a series of short steps with immediately feedback from users to ensure that development is proceeding correctly. All Right Reserved, Zhong YAO, School of E&M, BHU

  20. 8.4 Alternative Development Methodologies • Developing processes: • Select an important sub-problem to be built first. User and the builder jointly identify a subproblem for which the initial DSS is constructed. This early joint effort sets up initial working relationships between the participants and opens the lines of communication. The subproblem should be small enough that the nature of the problem, the need for computer-based support, and the nature of the at support are clear. It should have high interest value to the decision maker even if that interest is short-live. All Right Reserved, Zhong YAO, School of E&M, BHU

  21. 8.4 Alternative Development Methodologies • Develop a small but usable system for the decision maker. No major system analysis or feasibility analysis is involved. In fact, the builder and the user go through all the steps of the system development process quickly, though on a small scale. The system should, out of necessarily, be simple. • Evaluate the system constantly. At the end of each cycle the system is evaluated by the user and builder. Evaluation is an integral part of the development process, and is the control mechanism for the entire iterative design process. The evaluation mechanism is what keeps the cost and effort of developing a DSS All Right Reserved, Zhong YAO, School of E&M, BHU

  22. 8.4 Alternative Development Methodologies • consistent with its value. At the end of the evolution a decision is made on whether to further refine the DSS, or to stop. • Refine, expand, and modify the system in cycles. Subsequent cycles expand and improve the original version of the DSS. All the analysis, design, construction, implementation, and evaluation steps are repeated in each successive refinement. • Advantages of Prototyping • Short developing time • Short user reaction time • Improve user understanding of the system, its information needs, and its capabilities. All Right Reserved, Zhong YAO, School of E&M, BHU

  23. 8.4 Alternative Development Methodologies • Low cost. • Disadvantages and Limitations • Gains maybe lost. • Gains includes: Understanding Information systems benefits and costs, a detailed description of the business’s information needs, an easy to to maintain information system design, a well-tested information system, and well-prepared users. • Combined with the critical success factor method • Depend on the DSS built by the end-user or a DSS team. All Right Reserved, Zhong YAO, School of E&M, BHU

  24. Prototyping Need Planning Analysis Design Implementation Prototype Prototype Not OK Prototype OK System All Right Reserved, Zhong YAO, School of E&M, BHU

  25. 8.4 Alternative Development Methodologies • Throwaway Prototyping • Like prototyping and SDLC • Analysis phase is thorough • Design prototypes assist in understanding the system • Example: can use Excel, then Visual Basic • Prototyping for DSS Development • Problems are semistructured or unstructured • Managers and developers may not completely understand problem • Use prototyping All Right Reserved, Zhong YAO, School of E&M, BHU

  26. Throwaway Prototyping (Figure 6.4) Need Planning Analysis Design Design Implementation Design Prototype Not OK Implementation System Design Prototype All Right Reserved, Zhong YAO, School of E&M, BHU

  27. 8.4 Alternative Development Methodologies • Why Prototyping? • Users and managers involved in every phase and iteration • Learning is part of design • Prototyping bypasses the information requirement definition • Short interval between iterations • Initial prototype must be low cost All Right Reserved, Zhong YAO, School of E&M, BHU

  28. 8.5 Team-Developed DSS • A team-Developed DSS needs: • Substantial effort. • Extensive planning and organization • Some generic activities • Group of people to build and to manage it (users, intermediaries, DSS builder, technical support experts and IS personnel) Size depends on • Effort • Tools • For example, some project needs 2-3 people, but other maybe 15-20 people. All Right Reserved, Zhong YAO, School of E&M, BHU

  29. 8.5 Team-Developed DSS • DSS development group varies: • Within the IS department • As a highly placed executive staff group • Within the finance or other functional area • Within the industrial engineering department • Within the management science group • Within the information center group • The process that a DSS team may follow depends on the specific application. The group may be temporary, created for a specific DSS, or it may be permanent, in which case the group members are assigned to specific DSS project. All Right Reserved, Zhong YAO, School of E&M, BHU

  30. 8.6 Team-Developed Versus User-Developed DSS • DSS 1970s and early 1980s were large-scale, complex systems designed primarily to provide organizational support. Therefore, these process needs team effort to complete and maintain. • Another approach is user-developed system. • Personal computers • Computer communication networks • PC-mainframe communication • Friendly development software • Reduced cost of software and hardware • Increased capabilities of personal computers • Enterprise-wide computing • Easy accessibility to data and models • Client/server architecture • Now OLAP • Balance All Right Reserved, Zhong YAO, School of E&M, BHU

  31. 8.7. End-user Computing andUser-Developed DSS • End-user Computing (end-user development): development and use of computer-based information systems by people outside the formal information systems areas. This definition includes many people, such as manager, professionals using PCs, Secretaries using Word processing tools, etc. • End-users Can be • At any level of the organization • In any functional area • Levels of computer skill vary • Growing All Right Reserved, Zhong YAO, School of E&M, BHU

  32. 8.7. End-user Computing andUser-Developed DSS • End-User Developed DSS Advantages • Short delivery time • Eliminate extensive and formal user requirements specifications • Reduce some DSS implementation problems • Low cost • End-User Developed DSS Risks • Poor Quality • Quality Risks • Substandard or inappropriate tools and facilities • Development process risks • Data management risks • Increased Security Risks • Problems from Lack of Documentation and Maintenance Procedures All Right Reserved, Zhong YAO, School of E&M, BHU

  33. 8.7. End-user Computing andUser-Developed DSS • Issues in Reducing End-User Computing Risks • Error detection • Use of auditing techniques • Determine the proper amount of controls • Investigate the reasons for the errors • Solutions • Spreadsheet errors • Should use same controls as normal IS All Right Reserved, Zhong YAO, School of E&M, BHU

  34. Application Type Developer Attributes Spreadsheet Database Others Age Gender Computer Confidence Domain Experience Application Expertise Development Expertise Math anxiety Cognitive style End-user development Application Outcomes Reliability Ease of use Maintainability Auditability Cost Problem/process Char. Problem Complexity Time Pressure Existence of Review Other Developer Configuration Developer Approach Singles Pairs 3+ Ad Doc Structured All Right Reserved, Zhong YAO, School of E&M, BHU

  35. 8.8. Objective-Oriented Developing Methods For DSS • Evolution of Objective-Oriented Technology • Simula Language for replacing Simulation Language • Use of auditing techniques (1967) • Ada and Midula-2 for information hiding, (70s) • Smalltalk, Xerox PARC, 1980 • C++, AT and T, 1981 • Visual Basic, Power Builder, Delphi etc. since 1994 • Java, C#, etc. 2000s All Right Reserved, Zhong YAO, School of E&M, BHU

  36. 8.8. Objective-Oriented Developing Methods For DSS • Main Concept of Objective-Oriented Technology • To analyze and resolve the problems, the initial views of the OOT is according to human being recognizing objective world and thinking ways • Objective world consists of many concrete things or events, abstract concept, planning etc. • Therefore, to study the problem of objective world, we can abstract them as objects. In OOT, the objects are basic elements. It is a core of analyzing problem. • What is Object? • Is of independent operations and behaviors program. • Object vs. procedure. All Right Reserved, Zhong YAO, School of E&M, BHU

  37. 8.8. Objective-Oriented Developing Methods For DSS • What is Object? • Actions executed by messages transferred between objects. • Each object possesses itself data structure and style for storing data • Each object possesses independent interface for accessing by other objects Object 1 User demand Object 2 Object 3 Object 4 Object 5 Object 6 All Right Reserved, Zhong YAO, School of E&M, BHU

  38. 8.8. Objective-Oriented Developing Methods For DSS • Object Class • If a object having same structure, operation, and the following same constraint rules • A class include: (1) name, (2) external interface, (3) internal presentation and (4) realization. • Characteristics: • Class Specification---interface • Realization--- each function how to do • Hierarchy (Lattice)---farther class, sub-class, sub-sub-class etc. • High level: generalization and commonality • Low level: specials and details All Right Reserved, Zhong YAO, School of E&M, BHU

  39. 8.8. Objective-Oriented Developing Methods For DSS • Characteristics of Objective-Oriented Technology • Abstraction: Any thing can be presented, structured and unstructured. For example, table, chair, graph, sound, rule, concept etc. But similar things will be abstracted into same class for their similar operations, structures, and limits) • Encapsulation: structure and procedure encapsulated into one whole class. This can be used for data hiding. Data in a class only can be accessed by its (this class) internal functions or data. • Inheritance: subclass can inherit partial or whole properties of its mother class. The subclass can extend some special properties that the mother class don’t have. • Polymorphism: one function can be used by different arguments. All Right Reserved, Zhong YAO, School of E&M, BHU

  40. 8.9. UML Technology for DSS • Resources: Universal Modeling Language • UML origins Booch Method91, 93; OMT-1 and –2 and OOSE (use case) • 1994, Rational Software Corporation, combining Booch, OMT and OOSE into UML. • Concept of UML • Core view: 4+1; • 4: Logical + Implementation + Process + Deployment • 1: Use Case • Figure presents with All Right Reserved, Zhong YAO, School of E&M, BHU

  41. Logical View Process View Deployment View 8.9. UML Technology for DSS End Users Functionality Programmers Software Management Implementation View Analysts/Testers Behavior Use Case View System Engineering System Topology, Delivery Installation, Communication System Integrators Performance, Scalability, Throughput All Right Reserved, Zhong YAO, School of E&M, BHU

  42. 8.9. UML Technology for DSS • 9 standard Diagrams • Static Views • Use Case Diagram • Class Diagram • Object Diagram • Component Diagram • Deployment Diagram • Dynamic Views • Sequence Diagram • Collaboration Diagram • State Chart • Activity diagram All Right Reserved, Zhong YAO, School of E&M, BHU

  43. 8.9. UML Technology for DSS • UML module • UML is Specifying(规范化), Visualization(可视化), Documentation(文档化), and Constructing(结构化) software module language, its focus is on becoming a standard modeling language not on standard program language. • Common metamodel(元模型) and Notation • UML is best for: • OOT development • Component-based development • Higher Visualization Requirement • Components Reuse • Assisting Evaluation, statistical operating flows • Easy implementation All Right Reserved, Zhong YAO, School of E&M, BHU

  44. 8.10. Developing DSS: Putting the System Together • Development tools and generators • Use of highly automated tools • Use of prefabricated pieces • Both increase the developer’s productivity • DSS Development System Includes • Request (query) handler • System analysis and design facility • Dialog management system • Report generator • Graphics generator All Right Reserved, Zhong YAO, School of E&M, BHU

  45. 8.10. Developing DSS: Putting the System Together • Source code manager • Model base management system • Knowledge-base (management) system • Object-oriented tools • Standard statistical and management science tools • Special modeling tools • Programming languages • Document imaging tools • DSS Development System Components • Some may be integrated into a DSS generator • Others may be added as needed All Right Reserved, Zhong YAO, School of E&M, BHU

  46. 8.10. Developing DSS: Putting the System Together • Components used to build a new DSS • Core of system includes development language or DSS generator • Construction by combining programming modules • Windows environment handles the interface All Right Reserved, Zhong YAO, School of E&M, BHU

  47. 8.11 Hardware & Software Selection • Hardware Selection • PCs • Unix workstations • Network of Unix workstations • Web servers • Mainframes • Typically use existing hardware • Software Selection (Complex because) • At start, information requirements, etc. are unknown • Hundreds of packages • Software updated rapidly • Price changes All Right Reserved, Zhong YAO, School of E&M, BHU

  48. 8.11 Hardware & Software Selection • Many people involved in decision • Language capability problems • Different tools might be needed • Many criteria • Technical, functional, end-user, and managerial issues • Inaccurate published software reviews • Might prefer a single vendor • Maybe use the AHP!!! All Right Reserved, Zhong YAO, School of E&M, BHU

  49. 8.12 DSS Technology Levels and Tools • Three Levels of DSS Technology • Specific DSS [the application] • DSS integrated tools (generators) [Excel] • DSS primary tools [programming languages] • Plus • DSS integrated tools • Now all with Web hooks and easy GUI interfaces • Relationships among the three levels (Figure 6.5) All Right Reserved, Zhong YAO, School of E&M, BHU

  50. 8.12 DSS Technology Levels and Tools Specific DSS DSS Generators (Spreadsheets, …) DSS Tools (Languages, …) All Right Reserved, Zhong YAO, School of E&M, BHU

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