TY - GEN
T1 - Mitigating the obsolescence of quality specifications models in service-based systems
AU - Torres, Romina
AU - Bencomo, Nelly
AU - Astudillo, Hernan
PY - 2012
Y1 - 2012
N2 - 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.
AB - 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.
KW - Quality of Service
KW - Requirements-awareness
KW - dynamically adaptive systems
KW - model@runtime
KW - requirements model
KW - service-based systems
UR - http://www.scopus.com/inward/record.url?scp=84871562021&partnerID=8YFLogxK
U2 - 10.1109/MoDRE.2012.6360076
DO - 10.1109/MoDRE.2012.6360076
M3 - Conference contribution
AN - SCOPUS:84871562021
SN - 9781467343893
T3 - 2012 2nd IEEE International Workshop on Model-Driven Requirements Engineering, MoDRE 2012 - Proceedings
SP - 68
EP - 76
BT - 2012 2nd IEEE International Workshop on Model-Driven Requirements Engineering, MoDRE 2012 - Proceedings
T2 - 2012 2nd IEEE International Workshop on Model-Driven Requirements Engineering, MoDRE 2012
Y2 - 24 September 2012 through 24 September 2012
ER -