Optimization of Multiple-Objective Web Service Selection Using Fractional Programming

The Service Oriented Approach (SOA) is based on the idea that distributed applications can be flexibly composed by integrating independently developed component services. Due to the fact that a large number of available services offer similar functionality, when choosing actual services to be included in the composition their non-functional (Quality of Service – QoS) properties must also be taken into account. On the other hand certain constraints regarding the required performances (i.e. the required QoS levels) may also be given. Therefore, web service selection presents a multiple-objective multiple constraint problem and in this paper we model it as a discrete multiple-objective linear fractional programming (MOLFP) problem. In order to solve this problem we use a previously published technique for generating strongly efficient solutions to a continuous MOLFP problem to the discrete case. We present a complete methodology for solving the multiple criteria web service selection problem and report the experimental results obtained by testing it on 50 random instances generated by varying the input parameters.