Requirements Evolution and Evolution Requirements with Constrained Goal Models

Abstract

Abstract. We are interested in supporting software evolution caused by changing requirements and/or changes in the operational environment of a software system. For example, users of a system may want new functionality or performance enhancements to cope with growing user population (changing requirements). Alternatively, vendors of a system may want to minimize costs in implementing requirements changes (evolution requirements). We propose to use Constrained Goal Models (CGMs) to represent the requirements of a system, and capture requirements changes in terms of incremental operations on a goal model. Evolution requirements are then represented as optimization goals that minimize implementation costs or customer value. We can then exploit reasoning techniques to derive optimal new specifications for an evolving software system. CGMs offer an expressive language for modelling goals that comes with scalable solvers that can solve hybrid constraint and optimization problems using a combination of Satisfiability Modulo Theories (SMT) and Optimization Modulo Theories (OMT) techniques. We evaluate our proposal by modeling and reasoning with a goal model for the meeting scheduling examplar.

Multi-objective reasoning with constrained goal models

“…[1] has offered a formalization of the next adaptation problem that chooses a next adaptation for an adaptive software system that minimizes the degree of failure over existing requirements. And [30] has exploited CGMs to capture evolution requirements, such as "System evolution shall minimize implementation costs" and showed how to conduct scalable reasoning over models that include such requirements.…”

Support of Justification Elicitation: Two Industrial Reports

“…Close to our work, some methods use a goal-oriented approach to support requirement elicitation and organization. Language and methodology like KAOS [17], i* [7] and globally all the Goal-oriented Requirements Languages (GRL) tackle challenges like evolution of requirements but also internal practices with a goal-oriented approach [20] and also are focused on accreditation client requirements [19]. All these goal modeling languages focus on who and what, but they do not try to capture the why.…”

OptiMathSAT: A Tool for Optimization Modulo Theories

“…Here we consider a variant of the problem of computing a lexicographically-optimum realization of a constrained goal model [60,59]. In this comparison, the three PB/MAXSMT objectives appearing in the original set of formulas are normalized so that their respective range is equal to [0, 1] and combined in a single max-min goal rather than lexicographically optimized.…”

“…Goal Models (GM) are used in Requirements Engineering to represent software requirements, objectives, and design qualities [77]. Constrained Goal Models (CGM) [59,60] are a novel, formal version of GM, representing AND/OR goal decomposition graphs which are enriched with constraints so that to handle preferences, numerical attributes and resources (e.g., scores, financial cost, workforce, etc. ).…”

“…OPTIMATHSAT is freely available for research and evaluation purposes [7], and it is currently used in some innovative projects [76,59,60,19].…”