Mitigating the obsolescence of quality specifications models in service-based systems

Romina Torres, Nelly Bencomo, Hernan Astudillo

Research output: Chapter in Book/Published conference outputConference publication


Requirements-aware systems address the need to reason about uncertainty at runtime to support adaptation decisions, by representing quality of services (QoS) requirements for service-based systems (SBS) with precise values in run-time queryable model specification. However, current approaches do not support updating of the specification to reflect changes in the service market, like newly available services or improved QoS of existing ones. Thus, even if the specification models reflect design-time acceptable requirements they may become obsolete and miss opportunities for system improvement by self-adaptation. This articles proposes to distinguish "abstract" and "concrete" specification models: the former consists of linguistic variables (e.g. "fast") agreed upon at design time, and the latter consists of precise numeric values (e.g. "2ms") that are dynamically calculated at run-time, thus incorporating up-to-date QoS information. If and when freshly calculated concrete specifications are not satisfied anymore by the current service configuration, an adaptation is triggered. The approach was validated using four simulated SBS that use services from a previously published, real-world dataset; in all cases, the system was able to detect unsatisfied requirements at run-time and trigger suitable adaptations. Ongoing work focuses on policies to determine recalculation of specifications. This approach will allow engineers to build SBS that can be protected against market-caused obsolescence of their requirements specifications.
Original languageEnglish
Title of host publicationMmodel-driven requirements engineering workshop (MoDRE), 2012 IEEE
Number of pages9
ISBN (Electronic)978-1-4673-4388-6
ISBN (Print)978-1-4673-4387-9, 978-1-4673-4389-3
Publication statusPublished - 2012
Event2nd IEEE international workshop on model-driven requirements engineering - Chicago, IL, United States
Duration: 24 Sept 2012 → …


Workshop2nd IEEE international workshop on model-driven requirements engineering
Abbreviated titleMoDRE 2012
Country/TerritoryUnited States
CityChicago, IL
Period24/09/12 → …

Bibliographical note

© 2012 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.


  • requirements-awareness
  • quality of service
  • service-based systems
  • dynamically adaptive systems
  • requirements model
  • model@runtime


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