Requirements as Goals and Commitments Too

Abstract

In traditional software engineering research and practice, requirements are classified either as functional or non-functional. Functional requirements consist of all functions the system-to-be ought to support, and have been modeled in terms of box-and-arrow diagrams in the spirit of SADT. Non-functional requirements include desired software qualities for the system-to-be and have been described either in natural language or in terms of metrics. This orthodoxy was challenged in the mid-90s by a host of proposals that had a common theme: all requirements are initially stakeholder goals and ought to be elicited, modeled and analyzed as such. Through systematic processes, these goals can be refined into specifications of functions the system-to-be needs to deliver, while actions assigned to external actors need to be executed. This view is dominating Requirements Engineering (RE) research and is beginning to have an impact on RE practice. We propose a next step along this line of research, by adopting the concept of conditional commitment as companion concept to that of goal. Goals are intentional entities that capture the needs and wants of stakeholders. Commitments, on the other hand, are social concepts that define the willingness and capability of an actor A to fulfill a predicate ϕ for the benefit of actor B, provided B (in return) fulfills predicate ψ for the benefit of actor A. In our conceptualization, goals are mapped to collections of commitments rather than functions, qualities, or actor assignments. We motivate the importance of the concept of commitment for RE through examples and discussion. We also contrast our proposal with state-of-theart requirements modeling and analysis frameworks, such as KAOS, MAP, i* and Tropos.

Exploring alternative designs for sociotechnical systems

“…As shown in [5], [8], traditional goal models need to be extended to adequately represent STSs that consist of autonomous actors. In particular, social dependencies, as used in i* and Tropos, do not capture the reciprocal nature of most social dependencies between a depender and a dependee.…”

“…The benefits of integrating commitments into goal models are discussed in [5], [8]. [8] proposes a shift in goal-oriented requirements engineering which we follow and use as a basis for our research.…”

“…[8] proposes a shift in goal-oriented requirements engineering which we follow and use as a basis for our research. [5] focuses on a different problem than ourswhether a specific agent's goals are supported.…”

Modeling Approach for Integration and Evolution of Information System Conceptualizations

“…Communication actions in this diagram are interpreted as triggering events: Submit, AppointReviewers, ReturnReview, Accept and Reject. The main problem with this diagram is that it does not represent how state transitions are related to service commitments between actors (Chopra et al, 2010). Interactions and states are necessary to describe behavior fully.…”

“…It does not mean that a reviewer must always accept to review every paper, which is appointed by the PC chair. But if the reviewer accepts the Appoint Reviewers action, then he enters into a commitment (Chopra et al, 2010) to Return Review into the opposite direction (see Figure 6). Sending of the review flow (see figure 7) by Reviewer to PC chair can be triggered by Return Review communication action, which is represented by the following interaction dependency: ReturnReview(Reviewer •••▸PC chair).…”