Mixed-Variable Requirements Roadmaps and their Role in the Requirements Engineering of Adaptive Systems

TL;DR

This paper introduces mixed-variable requirements roadmaps to enhance requirements engineering for adaptive systems, integrating quantitative and qualitative variables and distinguishing monitored from controlled variables to support control loops.

Contribution

It provides a new formal definition of the requirements problem for adaptive systems and proposes a proto-framework for early requirements engineering in this domain.

Findings

Formalizes the differences between traditional and adaptive requirements engineering

Defines a proto-framework for early requirements engineering of adaptive systems

Bridges gap between requirements problem definitions and adaptive system needs

Abstract

The requirements roadmap concept is introduced as a solution to the problem of the requirements engineering of adaptive systems. The concept requires a new general definition of the requirements problem which allows for quantitative (numeric) variables, together with qualitative (binary boolean) propositional variables, and distinguishes monitored from controlled variables for use in control loops. We study the consequences of these changes, and argue that the requirements roadmap concept bridges the gap between current general definitions of the requirements problem and its notion of solution, and the research into the relaxation of requirements, the evaluation of their partial satisfaction, and the monitoring and control of requirements, all topics of particular interest in the engineering of requirements for adaptive systems [Cheng et al. 2009]. From the theoretical perspective, we show clearly and formally the fundamental differences between more traditional conception of requirements engineering (e.g., Zave & Jackson [1997]) and the requirements engineering of adaptive systems (from Fickas & Feather [1995], over Letier & van Lamsweerde [2004], and up to Whittle et al. [2010] and the most recent research). From the engineering perspective, we define a proto-framework for early requirements engineering of adaptive systems, which illustrates the features needed in future requirements frameworks for this class of systems.