1. Towards a Model-based COTS-Aware Requirements Engineering Approach Lawrence Chung and Kendra Cooper MBRE ‘01

2. Today... zIntroduction (Why CARE?) zOur Preliminary CARE Approach zCurrent State of the CARE Research zConclusions zFuture Work

3. Introduction - Why CARE? zStandard COTS Approach (e.g. RUP) yDevelop Requirements yDevelop Architecture yDevelop Detailed Design and Consider COTS xHere, COTS Components Must Meet Functional & Non-functional Requirements AND Fit With the Architecture zDetailed Design Phase Is Too Late yDifficult to Find COTS Components  Consider COTS in the Requirements Phase

4. An Ideal CARE Approach zCustomer “Satisficing” yFlexibility of Customer Requirements yMatching and Selecting COTS Components yGoal-oriented zMethod (or Process) Based zKnowledge-Based zShould Consider the Impact on Entire SDLC

5. Our Preliminary CARE Approach Baselined System Goals (with COTS) RE Initial Goals Corrections to System Requirements Corrections to Refined Requirements Define System Agents 1 RE Define Hardware Requirements 5 RE Define Interface Requirements 6 Agents Define System Goals 2 RE Define System Requirements 3 RE Foreign Goals Foreign Requirements Initial System Concept Define Software Requirements 4 RE Baselined System Req. (with COTS) Updated Foreign Goals Updated Foreign Reqs. IDEF0

6. Our Preliminary CARE Approach z Methodology y Select Information System Example x Digital Library System y Develop a System Level Specification y Use a Middle Out Strategy x Start With Step “Define System Requirements” * y Use Small Examples From the Library System x Define and Validate the Process x Define the Knowledge-Base (repository) yUse i*, NFR, and IDEF0 notations * Subsequent Steps: Define System Goals, Define System Agents Define Software, Interface, and Hardware Requirements

7. Preliminary CARE Approach Within Schedule Within Budget High Quality Validate System Create Baselined System Reqs with COTS … … Legend Decomposition Dependency Create System Strategic Rational and Dependency Models for CARE … Create Baselined System Goals with COTS Create Baselined Software Reqs. with COTS Create System Planning Artifacts Create System Goals Create System Requirements Create Software Requirements Customer Requirements Engineer Create System Product Artifacts i*

8. Preliminary CARE Approach i* Create Baselined System Requirements (with COTS) Legend Decomposition Create Baselined System Reqs. (with COTS) Elicit System Reqs. Analyze System Reqs. Correct System Reqs. Define COTS Reqs. Verify System Reqs. Baseline System Reqs. Component Repository System Requirementsss Component Repository Select Candidate Reqs. Prelim. Search of Repository Select Component Detailed Search of Repository Component Repository Detailed Match of Components Prelim. Match of Components Request Change to Component Request Change to Req. Maintain Components Component Repository Trace System Reqs.

9. Preliminary CARE Approach zExample (Digital Library System) zDefine System Goals yElicit Initial System Goal xDigital Library Should Comply With Current Standards yRefine System Goal x Digital Library Should Comply With ANSI/NISO Z39.50- 1995 (version 3) y Baseline System Goals

10. Preliminary CARE Approach zDefine System Requirements (with COTS) yElicit Initial System Requirements y Select Candidate System Requirements y Preliminary Search, Preliminary Match y Detailed Search, Detailed Match x MatchBlue Angel, Metastar Gateway & Server Components Z39.50 version 3 y Select Component y Correct System Requirements y Baseline System Requirements

11. Current State of CARE zAddresses COTS at “Define System Goals” Step yValidation Uses Another Example From the Digital Library System yThe Example Is More complex: Conflicting Set of Functional and Non-functional Goals xConfigurability of CHI, Performance, Cost,...

12. Current State of CARE Goal N … System Requirement N … Interface Requirement N Hardware Requirement N Software Requirement N Softgoal N Goals F System Requirements F Component 2 Goals F System Requirements F Component n Goals F System Requirements F Component 1 System Under Development (Native Goals, Native Requirements) Component Repository (Foreign Goals, Foreign Requirements) Mapping Native Goals and Requirements to Foreign Goals and Requirements Mapping Native Goals to Foreign Goals Mapping Native System Requirements to Foreign System Requirements Legend Agent

13. Current State of CARE Relationships Among Native Goals and Softgoals Librarians, Borrowers, System Administrators, Managers of Librarians and System Administrators Procurement Office System Administrators, Librarians, Borrowers (novice) - 2d 3a 4a - 5a - 2a - 2b 2c + -- - - Librarians, Borrowers, System Administrators, Managers of Librarians and System Administrators Librarians, Borrowers, System Administrators, Managers of Librarians and System Administrators System Administrators, Librarians, Borrowers (expert) Legend Goal Softgoal Relationship between Goals/Softgoals Relationship between Agents and Goals/Softgoals - Negative Relationship + Positive Relationship Agent Librarians, Borrowers, System Administrators, Managers of Librarians and System Administrators

14. Conclusions zUse of COTS Components is a Complex Problem yRequires a Systematic Approach yOur Methodology Seems to be Working zPreliminary CARE Approach is Serving as a Foundation yCARE Approach is Being Elaborated, Refined, and Validated

15. Future Work zContinue the Definition and Validation of the CARE Approach yFormal Representation and Reasoning of Goal Conflicts yBuild Knowledge-Base (repository) yTrade-off Analysis for Possible Configurations yInvestigate the Impact of CARE on System Architecture, Development Costs, Maintenance,...