QoS model Sample Clauses

QoS model. There are various QoS properties in the open SOC environment. They are often treated in accordance with domain-specific semantics. Nevertheless, as long as the QoS properties are negotiable between service consumers and providers and specifiable in SLAs, they can be accommodated by XXXX. In addition, in service composition scenarios, the component services collectively fulfil the QoS requirements for the composite services. In order to evaluate the quality of a composite service, the quality of the component services need to be aggregated. Component services may have various QoS properties, some of which can be aggregated4 while others cannot. The former properties are defined as compatible properties (e.g. price and execution time) and the latter are defined as incompatible properties (e.g. colours and shapes of goods). The formal definitions are given as follows: • both services have the property; AND • the corresponding property of the combination of the two services can be attained by aggregating the properties of the two services. • one service has the property while the other does not; OR • both services have the property but the corresponding property of the combination of two services cannot be attained by aggregating the two services. We aggregate the compatible QoS of the component services to obtain the QoS of the composite service based the workflow patters [95]. For the demonstration purpose, the definitions and aggregation functions for price and execution time, which are used in the example presented in this thesis, are as follows.