Time-Dependent QoS Aware Best Service Combination Selection

International audienceService Oriented Architecture allows developing complex business applications from existing services.Given that many services are available with the same functionality and with different Quality of Service(QoS) attributes, one common challenge is to select the best service combination regarding user’srequirements. Existing solutions often consider static QoS values for candidate services. Nevertheless, inreal world applications, QoS values can change during time. In addition, besides structural constraints,several QoS and temporal constraints can also be specified at the business level. Considering timedependentQoS values associated with business level constraints makes the selection process a verycomplex and time consuming decision problem given the large number of service combinations to becompared. To deal with this issue, in this paper, we propose a novel service selection approach based onQoS and temporal pruning techniques to reduce the number of candidate services. The proposed approachallows pruning uninteresting services based on a set of local thresholds. These latter are measured usingconstraint optimization models while dealing with general flow structures including sequential, parallel,choice and loop patterns and different types of QoS and temporal constraints. Experimental studies showthe benefits of the proposed approach in particular in terms of computational time