5

2Object-Oriented Analysis and Design with the Unified Process Objectives  Describe the activities of the requirements discipline  Describe the difference between functional and nonfunctional system requirements  Describe the kind of information that is required to develop system requirements  Explain the many reasons for creating information system models

3Object-Oriented Analysis and Design with the Unified Process Objectives (continued)  Determine system requirements through review of documentation, interviews, observation, prototypes, questionnaires, vendor research, and joint application design sessions  Discuss the need for validation of system requirements to ensure accuracy and completeness and the use of a structured walkthrough  Discuss the need for validation of system requirements and the use of a structured walkthrough

4Object-Oriented Analysis and Design with the Unified Process Activities of the requirements discipline

5Object-Oriented Analysis and Design with the Unified Process Gather Detailed Information  Analysts need to dialog with users of new system  Analysts should dialog with users of similar systems  Analysts must read documentation on existing system  Develop expertise in business area system will support  Other technical information should be collected  Computer usage, work locations, system interfaces, and software packages

6Object-Oriented Analysis and Design with the Unified Process Define Requirements  Models record/communicate functional requirements  Modeling continues while information is gathered  Process of refining is source of learning for analyst  Specific models built depend on developing system

7Object-Oriented Analysis and Design with the Unified Process Prioritize Requirements  Users tend to request sizeable number of functions  Why required?  Resources are always limited  Analyst must always be prepared to justify the scope of the system  Minimal cost and time

8Object-Oriented Analysis and Design with the Unified Process Develop User Interface Dialogs  Users familiar with functionality of interface  User feedback on new interface is reliable  Interface dialogs  Validate interface requirements  May be paper storyboards or prototype  Can be expanded to become a fully completed version of system

9Object-Oriented Analysis and Design with the Unified Process System Requirements  Define the functions to be provided by a system  System requirements fall into two categories  Functional : describes an activity or process that the system must perform ◘Directly related to use cases ◘Documented in graphical and textual models  Nonfunctional : characteristic of the system ◘Performance, technical, usability, reliability, and security ◘Documented in narrative descriptions to models

10Object-Oriented Analysis and Design with the Unified Process Models and Modeling  Analyst needs a collection of models to understand system requirements  Models are great communicators  Leverage visual cues to convey information  Reduce complexity of components to essentials  Models - show problem and solution  UML activity diagram is one type of model  Focuses on both user and system activities

11Object-Oriented Analysis and Design with the Unified Process The Purpose of Models

12Object-Oriented Analysis and Design with the Unified Process Types of Models  Models chosen based on nature of information  Selection process begins with categorization  Mathematical models  Descriptive models  Graphical models

13Object-Oriented Analysis and Design with the Unified Process Mathematical Models  Series of formulas describing technical aspects  Scientific, engineering, and business applications depend on mathematical models  Specific examples  Equations representing network throughput  Function expressing query response time

14Object-Oriented Analysis and Design with the Unified Process Descriptive Models  Narrative description, memos, reports, or lists  Provide high-level views  Usually incorporated into graphical schemes

15Object-Oriented Analysis and Design with the Unified Process Some descriptive models: Example

16Object-Oriented Analysis and Design with the Unified Process Graphical Models  Representations of some aspect of a system  Graphical models provide instant information  Unified Modeling Language (UML)  Provides standards for object-oriented models

17Object-Oriented Analysis and Design with the Unified Process Overview of Models Used in Requirements and Design

18Object-Oriented Analysis and Design with the Unified Process Additional models used in Requirements and Design

19Object-Oriented Analysis and Design with the Unified Process Techniques for Information Gathering  a. Question themes:  Questions center around three themes  What are business processes? E.g: What do you do?  How is the business process performed? E.g: How do you do it? What steps do you follow?  What information is required? E.g: What information do you use?

20Object-Oriented Analysis and Design with the Unified Process Techniques for Information Gathering (continued)  b. Review existing reports, forms and procedure descriptions, example:

21Object-Oriented Analysis and Design with the Unified Process Techniques for Information Gathering (continued)  c. Conduct interviews and discussions with the users

22Object-Oriented Analysis and Design with the Unified Process Techniques for Information Gathering (continued)  d. Observe business processes  e. Building effective prototypes  Discovery : to verify a concept  Evolving : grows and changes –become part of a system  Mock-up : for viewing only NOT executable  f. Distribute and Collect Questionnaires

23Object-Oriented Analysis and Design with the Unified Process Techniques for Information Gathering (continued)  g. Conduct Joint Application Design Sessions (JAD)  Includes JAD Session Leader, users, technical staff, project team members

24Object-Oriented Analysis and Design with the Unified Process Validating the Requirements  Two basic approaches to validating requirements  Predictive development ◘Requirements assumed stable and feasible ◘Requirements specified and validated beforehand  Adaptive development (embodied in UP) ◘Requirements are assumed difficult to document ◘Requirements subject to change ◘System prototypes used in validation process

25Object-Oriented Analysis and Design with the Unified Process Validating the Requirements (continued)  Structured walkthrough  Reviews findings  Reviews models based on findings  Objective: find errors and problems  Purpose: ensure that model is correct  Conducting structured walkthrough  Preparation  Execution  Follow-up

26Object-Oriented Analysis and Design with the Unified Process Summary  System requirements: functional and nonfunctional  Discipline activities: information gathering, definition, prioritization, and evaluation of requirements, and the development of user interface dialogs.  Models: reduce complexity and promote learning  Model types: mathematical, descriptive, graphical  UML: standard modeling notation  Seven primary techniques for gathering information  Joint application design (JAD): comprehensive information gathering technique  Validate by testing prototypes or completing structured walkthroughs