管理信息系统Session Four.ppt

1、Management Information System,Presented by Jie Jiang ,Management Information System,Information systems are developed and used in the business organizations. In previous sessions, we learned that managers can be found on all levels and in all business areas and business operation of the firm. The ba

2、sic business areas of the firm are finance, human resources, information services, manufacturing, and marketing.,Management Information System,General System Model of the Firm,Management Information System,Information Systems Support for the Organization Information systems have been developed to su

3、pport the entire organization, executives, and the business areas. The MIS is intended to meet the general information needs of managers throughout the firm; the executive information system is designed for use by the firms strategic level managers; and the five information systems on the lower leve

4、l of the figure address the unique information needs f those business areas.,Management Information System,Information Systems Are Developed to Support Organizational levels and Areas,Management Information System,An organizational structure for a firms Centralized Information Service Unit,Managemen

5、t Information System,A Network Model of Information Systems Organization,Management Information System,These information systems are tailored to the physical organization, that is, the way that the physical resources (human, material, machine, and money) are allocated to the various physical areas o

6、f the firm global subsidiaries, divisions, regions, districts, branches, and so on. Innovations in information technology have made it possible for many of the firms activities to be conducted without the constraints of physical location. Such an organizational structure is called the virtual organi

7、zation.,Management Information System,System Development The traditional waterfall model The Waterfall model outlines the series of steps that should occur when building a MIS. These steps usually occur in a predefined order with a review at the end of each stage before the next can be started. The

8、purpose of the waterfall model of systems development is to divide the development process up into a series of manageable parts that relate to each other in an organized way. In addition, some tasks will have to be completed before others can commence. For example, it will not be possible for a prog

9、rammer to start writing a program until the design specification for that program is complete,Management Information System,System Development The traditional waterfall model The waterfall model is a simple representation of what actually happens during a systems development project, but it provides

10、 a good framework for introducing information systems development, since all of the activities that are identified in the model occur in a typical project.,Management Information System,System Development System development lifecycle (SDLC) Whatever their scope and objectives, new information system

11、s are an outgrowth of a process of organizational problem solving. A new information system is built as a solution to some type of problem or set of problems the organization perceives it is facing. The activities that go into producing an information systems solution to an organizational problems o

12、r opportunity. Systems development is a structured kind of problem solving with distinct activities. These activities consist of systems analysis, systems design, programming, testing, conversion, and production and maintenance.,Management Information System,System Development System development lif

13、ecycle (SDLC) The SDLC approach recognises that systems are developed in a series of steps or phases and that each phase needs to be completed before the next one commences. Recognition is also given to the fact that the programming activity (part of the build phase) should only commence once user r

14、equirements have been determined and the system design produced.,Management Information System,System development lifecycle,Management Information System,System Development System development lifecycle (SDLC) System analysis The analysis of a problem that the organization will try to solve with an i

15、nformation system. It consists of defining the problem, identifying its causes, specifying the solution, and identifying the information requirements that must be met by a system solution. Systems analysis can also be used to identify new opportunities for using information technology.,Management In

16、formation System,System Development System development lifecycle (SDLC) Feasibility Study As part of the systems analysis process, the way to determine whether the solution is achievable, given the organizations resources and constrains. Technical feasibility Determines whether a proposed solution c

17、ab be implemented with the available hardware, software, and technical resources. Economic feasibility Determine whether the benefits of a proposed solution outweigh the costs,Management Information System,System Development System development lifecycle (SDLC) Feasibility Study Normally the systems

18、analysis process will identify several alternative solutions that can be pursued by the organization. The process will then assess the feasibility of each. Three basic solution alternatives exist for every systems problems: To do nothing, leaving the existing situation unchanged. To modify or enhanc

19、e existing systems To develop a new system,Management Information System,System Development System development lifecycle (SDLC) Establishing Information Requirements A detailed statement of the information needs that a new system must satisfy; identifies who needs what information, and when, where,

20、and how the information is needed. Requirements analysis carefully defines the objectives of the new or modified system and develops a detailed description of the functions that the new system must perform. Requirements must consider economic, technical, and time constraints, as well as the goals, p

21、rocedures, and decision processes of the organization.,Management Information System,System Development System development lifecycle (SDLC) Establishing Information Requirements Developing requirements specifications may involve considerable research and revision. To derive information systems requi

22、rements, analysts may be forced to work and rework requirements statements in cooperation with users.,Management Information System,System Development System development lifecycle (SDLC) System design Details how a system will meet the information requirements as determined by the system analysis. L

23、ogical design Lays out the components of the information system and their relationship to each other as they would appear to users. It shows what the system solution will do as opposed to how it is actually implemented physically. It describes inputs and outputs, processing functions to be performed

24、, business procedures data models, and control.,Management Information System,System Development System development lifecycle (SDLC) Physical design The process of translating the abstract logical model into the specific technical design of the new system. It produces the actual specifications for h

25、ardware, software, physical databases, input/output media, manual procedures, and specific controls. The role of end-users User information requirements drive the entire systems-building effort. Users must have sufficient control over the design process to ensure that the system reflects their busin

26、ess priorities and information needs, not the biases of the technical staff. (Hunton and Beeler, 1997).,Management Information System,System Development System development lifecycle (SDLC) Programming The process of translating the system specifications prepared during the design stage into program

27、code. Testing The exhaustive and thorough process that determines whether the system produces the desired results under known conditions. Unit testing System testing Acceptance testing,Management Information System,System Development System development lifecycle (SDLC) Testing plan Prepared by the d

28、evelopment team in conjunction with the users, it includes the preparations for the series of tests to be performed on the system. Conversion Conversion is the process of changing from the old system to the new system. Four main conversion strategies can be employed; the parallel strategy, the direc

29、t customer strategy, the pilot study strategy, and the phased approach strategy.,Management Information System,System Development System development lifecycle (SDLC) Conversion strategy Parallel strategy A safe and conservative conversion approach in which both the old system and its potential repla

30、cement are run to gather for a time until everyone is assured that the new system functions correctly. Direct cutover strategy A risky conversion approach in which the new system completely replaces the old one on an appointed day.,Management Information System,System Development System development

31、lifecycle (SDLC) Conversion strategy Pilot study strategy A strategy to introduce the new system to a limited area of the organization until it is proven to be fully functional; only then can the conversion to the new system across the entire organization take place. Phased approach strategy Introdu

32、ces the new system in stages either by functions or by organizational units.,Management Information System,System Development System development lifecycle (SDLC) Conversion plan Provides a schedule of all activities required to install a new system. The most time-consuming activity in many cases is

33、the conversion of data. Documentation Descriptions of how an information system works from both a technical and end-user standpoint.,Management Information System,System Development System development lifecycle (SDLC) Production The stage after the new system is installed and the conversion is compl

34、ete; during this time the system is reviewed by users and technical specialists to determine how well it has met its original goals. Maintenance Changes in hardware, software, documentation, or procedures to a production system to correct error, meet new requirements, or improve processing efficienc

35、y.,Management Information System,Limitations of the Lifecycle Approach The system lifecycle approach is costly, time-consuming, and inflexible. Volumes of new documents must be generated and steps repeated if requirements and specifications need to be revised. Formal specification of requirements ma

36、y inhibit system-builders from exploring and discovering the problem structure (Fraser et al., 1994). the lifecycle approach is not suitable for many small desktop systems, which tend to be less structured and more individualized.,Management Information System,Prototyping Prototyping The process of

37、building an experimental system quickly and inexpensively for demonstration and evaluation so that users can better determine information requirements. Prototype The preliminary working version of an information system for demonstration and evaluation purposes.,Management Information System,Prototyp

38、ing The prototype is a working version of an information system or part of the system, but it is meant to be only a preliminary model. Once operational, the prototype will be further fined until it conforms precisely to users requirements. Once the design has been finalized, the prototype can be con

39、verted t a polished production system. Steps in Prototyping Step 1: identify the users basic requirements. The system designer (usually an information systems specialist) works with the user only long enough to capture his or her basic information needs.,Management Information System,Step 2: develop

40、 an initial prototype. The system designer creates a working prototype quickly, most likely using the fourth-generation software tools that speed application development. Some features of computer-aided software engineering (CASE) tools can be used for prototyping as can multimedia software tools th

41、at present users with interactive storyboards that sketch out the tasks of the proposed system for evaluation and modification (Madsen and Aiken, 1993). (See Fig-2 The prototyping process). Step 3 Use the prototype. The user is encouraged to work with the system in order to determine how well the pr

42、ototype meets his or her needs and to make suggestion for improving the prototype.,Management Information System,Step 4: Revise and enhance the prototype The system builder notes all changes requested by the user and refines the prototype accordingly. After the prototype has been revised, the cycle

43、returns to step 3. Advantages and Disadvantages of Prototyping Prototyping is most useful when there is some uncertainty about requirements or design solutions. Prototyping is especially valuable for the design of the end-user interface of an information system (the part of the system that end users

44、 interact with, such as on-line display and data-entry screens, reports, or Web pages) The prototype enable users to react immediately to the parts of the system with which they will be dealing. (See Fig-2),Management Information System,Prototyping encourages intense end-user involvement throughout

45、the systems development lifecycle (Cerveny et al., 1986). Prototyping is more likely to produce systems that fulfill user requirements. Prototyping is better suited for smaller applications. Large systems would have to be subdivided so that prototypes could be built one part at a time (Alavi, 1984),

46、 which may not be possible without a thorough requirements analysis using the conventional approach. Rapid prototyping can gloss over essential steps in systems development. Once finished, I the prototype works reasonably well, management may not see the need for reprogramming, redesign, or full doc

47、umentation and testing. Successful prototyping requires management and mechanisms for defining expectations, assigning resources, signaling problems, and measuring progress (Baskerville and Stage, 1996).,Management Information System,Prototyping Potential Pitfalls of Prototyping The haste to deliver

48、 the prototype may produce shortcuts in problem definition, alternative evaluation, and documentation. The shortcuts produce a “quick and dirty” effort. The user may get overly excited about the prototype, leading to unrealistic expectations regarding the productions system. Evolutionary prototypes

49、may not be very efficient. The computer-human interface provided by certain prototyping tools may not reflect good design techniques.,Management Information System,Prototyping Potential Pitfalls of Prototyping Both users and developers should be aware of these potential pitfalls when they elect to p

50、ursue the prototyping approach. However, on balance, prototyping has proven to be one of the most successful SDLC methodologies. It would be difficult to find a development project that did not incorporate prototyping to some degree.,Management Information System,Rapid Application Development A meth

51、odology that has the same objective of speedy response to user needs as does prototyping but is broader in scope is RAD. The RAD, for rapid application development, was coined by computer consultant and author James Martin, and it refers to a development life cycle that is intended to produce system

52、s quickly without sacrificing quality.,Management Information System,Rapid Application Development (RAD) RAD is an integrated set of strategies, methodologies, and tools that exists within a framework called information engineering. Information engineering (IE) is the name that Martin gives t his ov

53、erall approach t system development, which he treats as a firmwide activity. The term enterprise is used to describe the entire firm.,Management Information System,Management Information System,Rapid Application Development (RAD) The above figure illustrates the RAD life cycle according to Martin, s

54、howing the amount of effort expended by both users and information specialists. The name of Martins life cycle stages differ somewhat from those we have used for the traditional SDLC, but the same sequence of work is involved. In the traditional life cycle, representatives from the information syste

55、ms department do the majority of work, with users only gaining momentum during cutover. The opposite is true in the RAD life cycle illustrated in the above figure where users play the major role except during construction. Martins underlying logic was that greater user involvement, especially during

56、 early Of than in the traditional life cycle.,Management Information System,Rapid Application Development (RAD) The Essential Ingredients of RAD RAD requires four essential ingredients: management, people, methodologies, and tools: Management, especially top management, should be experimenters who l

57、ike to do things a new way or early adapters who quickly learn how to use new methodologies.,Management Information System,Rapid Application Development (RAD) The Essential Ingredients of RAD Rather than utilize a single team t perform all of the SDLC activities, RAD recognizes the efficiencies that

58、 can be achieved through the use of specialized teams. Members of these teams are masters of the methodologies and tools that are required to perform their specialized tasks. Martin uses the term SWAT team, with SWAT standing for “skilled with advanced tools.”,Management Information System,Rapid App

59、lication Development (RAD) The Essential Ingredients of RAD The basic RAD methodology is the RAD life cycle. RAD tools consist mainly of fourth-generation languages and computer-aided software engineering (CASE) tools that facilitate prototyping and code generation. CASE tools use the computer to pr

60、epare documentation that can be transformed into operational software and databases.,Management Information System,Rapid Application Development (RAD) The Essential Ingredients of RAD Of all the components of information engineering, RAD has probably enjoyed the greatest support. Although it may not