A COTS-Aware Requirements Engineering Process: a Goal- and Agent-oriented Approach
Lawrence Chung and Kendra Cooper University of Texas at Dallas MS 31 P.O. Box 830688 Richardson, TX, USA 75083-0688 chung@utdallas.edu kcooper@utdallas.edu
Abstract. The goals of developing systems better, faster, and cheaper continue to drive software engineering practitioners and researchers to investigate software engineering methodologies. In requirements engineering, the focus has been on modeling the software engineering process and products for systems that are being built from scratch. As the size and complexity of systems continues to grow the use of commercial off the shelf (COTS) components is being viewed as a solution. Effective use of COTS components, however, requires a systematic approach that provides both a set of concepts for modeling the subject matter and a set of guidelines for using such concepts. In particular, the process needs to recognize and address the people oriented problems including the identification and resolution of conflicting goals, bridging the gaps between stated requirements and 'approximately fitting' components while still satisfying the customer. In this paper, we present a goal and agent oriented requirements engineering process model that explicitly addresses the use of COTS components. More specifically, we present (part of) our model for a COTS-Aware Requirements Engineering (CARE) process and illustrate it using a Digital Library System. INTRODUCTION The goal of developing systems better, fast, and cheaper continues to drive software engineering practitioners and researchers to investigate software engineering methodologies. In requirements engineering, the focus has been on describing the functional requirements for systems that are being built from scratch. As the size and complexity of systems continues to grow the use of commercial off the shelf (COTS) components is being viewed as a solution to this problem. Effective use of COTS components, however, requires a systematic methodology that would provide both a set of concepts for modeling the subject matter and a set of guidelines for using such concepts. In particular, the methodology needs to recognize and address the people oriented problems including the identification and resolution of conflicting goals as well as bridging the gaps between stated requirements and 'approximately fitting' components while still satisfying the customer. Our work, the COTS-Aware Requirements Engineering (CARE) approach, is focused on creating and modeling a requirements engineering approach that explicitly supports the use of commercial off the shelf (COTS) components. It is both goal oriented as in (Anton 1998, Chung 2000, van Lamsweerde 2000), and agent oriented (as in Yu 1994). The process is intended to assist the requirements engineer, not to replace their intelligence and experience. There are two models that describe the CARE approach: a process model and a product model. The process model is the focus of this work. Due to space limitations, here we present only part of the process model and demonstrate its use with a Digital Library System application. A more complete descripton is available in (Chung 2001). In related work, the Rational Unified Process (RUP) is an object oriented software engineering technique (Jacobson 1999), which is based on four phases (transition, construction, elaboration, and inception) and five core workflows (requirements, analysis, design, implementation, test), and uses the unified modeling language (UML). In UML, a COTS component is represented as a component, a physical and replaceable part of the system that provides a set of interfaces and typically represents the physical packaging of classes, interfaces, and collaborations (Krutchen 1998). The Model Based Architecting and Software Engineering (MBASE) approach considers four types of models: success, process, product and property (Boehm 1998) and is consistent for use with COTS components (Boehm 2000). MBASE uses four guiding principles to develop value-driven, sharedvision-driven, change-driven, and risk-driven requirements. The Procurement Oriented Requirements Engineering (PORE) technique supports the evaluation and selection of COTS components (Ncube 1998). The PORE process model identifies four goals that need to be performed in a thorough COTS selection process: acquiring information from the stakeholders, analyzing the information to determine if it is complete and correct, making the decision about product requirement compliance if the acquired information is sufficient, and selecting one or more candidate COTS components.

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