Analysis of Quality Dependencies in the Composition of Software Architectures

Abstract

A dependable system has to meet some quality criteria in order to provide certain reliance on its operation. The quality of a system depends on the complex composition of the quality of its subsystems. Specications of non-functional properties are commonly used to describe provided quality, required quality, resource usage and resource availability. Enclosing these specifications along with architectural models allows performing preliminary quality assessments (design-phase analysis). We allow configuration choices for quality specifications to represent design choices, deployment choices, or component adaptability. We focus on a composition study that answers to: is it possible to meet system and subsystem requirements given provided qualities? and, which configuration allows satisfying the requirements? The contributions of this work are: i) to formalize the composition based on quality levels and constraints, ii) to analyze existing quality dependencies in such a composition, iii) to show how we represent and evaluate dependencies in a model driven environment.