Pre-Joined Semantic Indexing Graph for QoS-Aware Service Composition

Abstract

Cloud computing users may obtain great flexibility with low cost by outsourcing their data and services to the cloud. Services are composed together as a solution when no individual services meet the goal. Unfortunately, searching an optimal composition requires significant time due to the high number of available services in the cloud. In this paper, we develop an approach that solves the composition problem with a graph database. This approach uses the shortest bidirectional breadth-first and Dijkstra algorithms to find solutions with either fewest services or the optimal QoS values. Firstly, we preprocess service compositions and store them as paths in a directed bipartite graph in graph database. Compared with using a relational database, the join operator can be avoided and the search speed increases. Secondly, this approach utilize existing resources and can be easily migrated to a cloud database. Correctness and feasibility of this system are verified with experimental results, which shows this system leads to good performance in finding users' satisfying solutions.