Phase 2 Systems Analysis. Dr. Feng-Jen Yang

Transcription

1 Phase 2 Systems Analysis Dr. Feng-Jen Yang

2 Phase Description Systems analysis is the 2nd phase in the systems development life cycle (SDLC) Use requirements modeling, data and process modeling, and object modeling techniques to represent the new system Consider various development strategies for the new system, and plan for the transition to systems design phase Dr. Feng-Jen Yang 2

3 Chapter 4 Requirement Modeling Part One Dr. Feng-Jen Yang

4 Objectives Describe systems analysis phase activities and the end product of the systems analysis phase Explain joint application development (JAD), rapid application development (RAD), and agile methods Understand how systems analysts use a functional decomposition diagram (FDD) Dr. Feng-Jen Yang 4

5 Objectives cont. Describe the Unified Modeling Language (UML) and explain use case diagrams and sequence diagrams List and describe system requirements, including outputs, inputs, processes, performance, and controls Explain the concept of scalability Dr. Feng-Jen Yang 5

6 Objectives cont. 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 Dr. Feng-Jen Yang 6

7 Introduction This chapter Describe requirements modeling techniques and teambased methods To visualize and document new systems Discuss system requirements and fact-finding techniques Include interview, documentation review, observation, surveys and questionnaires, sampling, and research Dr. Feng-Jen Yang 7

8 Systems Analysis Phase Overview The overall objective is to Understand the proposed project Ensure that it will support business requirements Build a solid foundation for system development Use models and other documentation tools To visualize and describe the proposed system Dr. Feng-Jen Yang 8

9 System Analysis Activities Dr. Feng-Jen Yang 9

10 System Analysis Activities cont. Requirements modeling Outputs Electronic or printed information produced by the system Inputs Necessary data that enters the system either manually or automatically Processes The logical rules to transform the data into meaningful information Dr. Feng-Jen Yang 10

11 System Analysis Activities cont. Performance System characteristics such as speed, volume, capacity, availability, and reliability Security Hardware, software, and procedural controls that safeguard and protect the system and its data Dr. Feng-Jen Yang 11

12 System Analysis Activities cont. Data and process modeling Graphically represent system data and processes using traditional structured analysis Identifies that data flowing into a process The business rules that transform the data The resulting output data flow Dr. Feng-Jen Yang 12

13 System Analysis Activities cont. Object Modeling Combine data and its processes into objects Represent actual people, things, transactions, and events Development Strategies Consider various development options Prepare for the transition to the systems design phase The deliverable of the systems analysis phase System requirements document Dr. Feng-Jen Yang 13

14 System Analysis Skills Analytical skills Identify a problem Evaluate the key elements Develop a useful solution Interpersonal skills Work with people at all organizational level Balance conflicting needs of users, and communicate effectively Dr. Feng-Jen Yang 14

15 Team-Oriented Methods and Techniques Joint application development (JAD) Rapid application development (RAD) Agile methods Dr. Feng-Jen Yang 15

16 Joint Application Development A popular fact-finding technique Bring users into the development process as active participants User involvement Users have a vital stake in an information system Should participate fully Successful systems must be user-oriented Users need to be involved Dr. Feng-Jen Yang 16

17 Joint Application Development cont. A JAD team approach involves a task force of Users, managers and IT professionals Work together to gather information, discuss business needs, and define the new systems requirements Dr. Feng-Jen Yang 17

18 Joint Application Development cont. Participant Project leader Top manager Managers Users Systems analysis and other IT staff members Recorder Role Develops an agenda, acts as a facilitator, and leads the JAD session Provides enterprise-level authorization and support for the project Provide department-level support of the project and understanding of how the project must support business functions and requirements Provide operation-level input on current operations, desired changes, input and output requirements, user interface issues, and how the project will support day-to-day tasks Provide technical assistance and resources for JAD team members on issues such as security, backup, hardware, software, and network capability Documents results of JAD sessions and works with systems analysts to build system models and develop CASE tool documentation Typical JAD Participants and Roles Dr. Feng-Jen Yang 18

19 Joint Application Development cont. Project leader Top manager Project leader Open discussion session, moderated by the project leader JAD team members working in smaller group sessions, supported by IT staff Group leaders Open discussion session, moderated by project leader Project leader Introduce all JAD team member Discuss ground rules, goals and objectives for the JAD sessions Explain methods of documentation and use of CASE tools, if any Explain the reason for the project and express top management authorization and support Provide overview of the current system and proposed project scope and constraints Present outline of specific topics and issues to be investigated Review the main business processes, tasks, user roles, input, and output Discuss and document all system requirements Develop models and prototypes Report on results and assigned tasks and topics Present issues that should be addressed by the overall JAD team Review reports from small group sessions Reach consensus on main issues Document all topics Present overall recap of JAD session Prepare report that will be sent to JAD team member Typical Agenda for a JAD Session Dr. Feng-Jen Yang 19

20 Joint Application Development cont. Disadvantages More expensive and can be cumbersome If the group is too large relative to the size of the project Advantages Allows key users to participate effectively When properly used can result in A more accurate statement of system requirements A better understanding of common goals A stronger commitment to the success of the new system Dr. Feng-Jen Yang 20

21 Rapid Application Development A team-based technique Speed up information systems development Produce a functioning information systems The end product A new system Dr. Feng-Jen Yang 21

22 Rapid Application Development cont. RAD Phases and Activities Dr. Feng-Jen Yang 22

23 Rapid Application Development cont. RAD Objectives To cut development time and expense By involving the users in every phase of systems development Successful RAD team must have IT resources, skills, and management support Helps a development team To design a system that requires a highly interactive or complex user interface Dr. Feng-Jen Yang 23

24 Rapid Application Development cont. Advantages Systems can be developed more quickly with significant cost savings Disadvantages Might allow less time to develop quality, consistency, and design standards RAD stresses the mechanics of the system itself and does not emphasize the company s strategic business needs Dr. Feng-Jen Yang 24

25 Agile Methods Attempt to develop a system incrementally By building a series of prototypes and constantly adjusting them to user requirement A large community of agile-related software and services has evolved For example, the Agilian offered by Visual Paradigm Include a set of agile modeling tools Support many modeling tools such as unified modeling language, enter-relationship diagrams, data flow diagrams and business process modeling Dr. Feng-Jen Yang 25

26 Agile Methods cont. Some agile developers prefer not to use CASE tools at all Rely on whiteboard displays and arrangements of movable sticky notes Dr. Feng-Jen Yang 26

27 Agile Methods cont. Advantages Are very flexible and efficient in dealing with change Frequent deliverables constantly validate the project and reduce risk Disadvantages Team members need a high level of technical and interpersonal skills May be subject to significant change in scope Dr. Feng-Jen Yang 27