SOCA (2016) 10:111–133 DOI 10.1007/s11761-014-0167-5 ORIGINAL RESEARCH PAPER Generalized semantic Web service composition Srividya Bansal · Ajay Bansal · Gopal Gupta · M. Brian Blake Received: 29 January 2014 / Revised: 31 August 2014 / Accepted: 23 October 2014 / Published online: 8 November 2014 © Springer-Verlag London 2014 Abstract With the increasing popularity of Web Services and Service-Oriented Architecture, we need infrastructure to discover and compose Web services. In this paper, we present a generalized semantics-based technique for auto- matic service composition that combines the rigor of process- oriented composition with the descriptiveness of semantics. Our generalized approach presented in this paper introduces the use of a conditional directed acyclic graph where complex interactions, containing control flow, information flow, and pre-/post-conditions are effectively represented. Composi- tion solution obtained is represented semantically as OWL-S documents. Web service composition will gain wider accep- tance only when users know that the solutions obtained are comprised of trustworthy services. We present a framework that not only uses functional and non-functional attributes provided by the Web service description document but also filters and ranks solutions based on their trust rating that is computed using Centrality Measure of Social Networks. Our contributions are applied for automatic workflow generation in context of the currently important bioinformatics domain. We evaluate our engine for automatic workflow generation of a phylogenetic inference task. We also evaluate our engine S. Bansal (B ) · A. Bansal Arizona State University, Mesa, AZ, USA e-mail: srividya.bansal@asu.edu A. Bansal e-mail: ajay.bansal@asu.edu G. Gupta The University of Texas at Dallas, Richardson, TX, USA e-mail: gupta@utdallas.edu M. B. Blake University of Miami, Miami, FL, USA e-mail: m.brian.blake@miami.edu for automated discovery and composition on repositories of different sizes and present the results. Keywords Service composition · Service discovery · Semantic Web · Ontology · Workflow generation 1 Introduction The next milestone in the evolution of the World Wide Web is making services ubiquitously available. As automation increases, Web services will be accessed directly by the appli- cations themselves rather than by humans [1, 2]. In this con- text, a Web service can be regarded as a “programmatic inter- face” that makes application-to-application communication possible. To make services ubiquitously available, we need infrastructure that applications can use to automatically dis- cover, deploy, compose, and synthesize services. A Web ser- vice is an autonomous, platform-independent program acces- sible over the web that may affect some action or change in the world. Sample of Web services include common plane, hotel, rental car reservation services or device controls like sensors or satellites. A Web service can be regarded as a “pro- grammatic interface” that makes application-to-application communication possible. Informally, a service is character- ized by its input parameters, the outputs it produces, and the actions that it initiates. The input parameter may be further subject to some pre-conditions, and likewise, the outputs pro- duced may have to satisfy certain post-conditions. In order to make Web services more practical, we need an infrastruc- ture that allows users to discover, deploy, synthesize, and compose services automatically. To make services ubiqui- tously available, we need a semantics-based approach such that applications can reason about a service’s capability to a level of detail that permits their discovery, composition, 123