The composition of Web-based services is a process that usually requires advanced programming skills and vast knowledge about specific technologies. One such modern technology is Web services. In this work, we propose a framework for the smooth composition of Web services that are targeted to provide particular government services that usually require interaction between several agencies. The goal is to allow government agencies to smoothly register simple services or create new ones based on other already registered simple or composed services. Our work has the additional goal of reducing the overhead involved in the execution of composite services by providing efficient mapping schemes to bypass intermediary composed services and allowing direct invocation of the basic services in the composition.

Abstract We consider the problem of transferring a set of files from their given locations in a fully connected network to their respective target locations in minimum time. We show that this problem is NP‐hard even with the restriction that no file uses more than two edges in its route. We present an efficient algorithm to solve this problem in the case when there is only one source and one or more destinations. For the general case, we propose a two‐phase approach to find two‐edge schedules that are optimal or close‐to‐optimal. In Phase I, two‐edge routes are assigned to files; in Phase II, a schedule is determined for the use of the links in these routes. For Phase I, we present an exact solution that is based on integer programming formulation and also give theoretical bounds for approximate solution. We also propose a route assignment algorithm that attempts to assign routes of minimum congestion. For Phase II, we present an efficient algorithm that constructs a schedule from the solution obtained in the first phase.

In a distributed database system there is a need for periodic changes in data distribution due to such factors as changes in query patterns and network topology. A proper redistribution of data is necessary to provide acceptable system performance, as measured by the average execution time of transactions. The problem of properly scheduling data transfers in order to complete this redistribution process in minimum possible time is investigated. This problem takes into account the constraints on communication resources of the system. The complexity of the problem is discussed, and a useful upper bound for optimal solutions is presented. Also given are procedures for finding optimal and approximate solutions to this problem.>