The challenge of optimally selecting services from a set of functionally appropriate ones under Quality of Service (QoS) constraints – the Service Selection Problem – has been extensively addressed... Show More

The challenge of optimally selecting services from a set of functionally appropriate ones under Quality of Service (QoS) constraints – the Service Selection Problem – has been extensively addressed in the literature based on deterministic parameters. In practice, however, Quality of Service QoS parameters rather follow a stochastic distribution. In the work at hand, we present an integrated approach which addresses the Service Selection Problem for complex structured as well as unstructured workflows in conjunction with stochastic Quality of Service parameters. Accounting for penalty cost which accrue due to Quality of Service violations, we perform a worst-case analysis as opposed to an average-case analysis aiming at avoiding additional penalties. Although considering conservative computations, QoS violations due to stochastic QoS behavior still may occur resulting in potentially severe penalties. Our proposed approach reduces this impact of stochastic QoS behavior on total cost significantly.

In spite of the widely recognized benefits of applying Service Oriented Architecture (SOA) to design enterprise-scale software systems, its actual application practice is not always a success. One... Show More

In spite of the widely recognized benefits of applying Service Oriented Architecture (SOA) to design enterprise-scale software systems, its actual application practice is not always a success. One major reason is the lack of a systematic engineering process and tool supported by reusable architectural artifacts. Toward this ultimate goal, this paper proposes a new method of architectural building blocks (ABB)-based SOA solution design and it is applicable to any layered or tiered infrastructure. The authors present the modeling of solution-level architectural artifacts and their relationships, whose formalization enables event-based variation notification and propagation analysis. The goal is to provide architecture-level support for configuration and re-configuration of architectural artifacts based on industry practices. Their method also supports solution-level project variation management for the process of updating and maintaining architectural artifacts. The authors report a prototype tool that they have developed and describe how they extend the Unified Modeling Language (UML) mechanism to implement the system and enable solution-level enforcement as an example. The prototype has been applied in real projects as an SOA solution modeling tool.

In this paper, we propose a bounded model-checking based approach for the verification of declarative Web services composition processes using satisfiability solving (SAT). The need for the bounded... Show More

In this paper, we propose a bounded model-checking based approach for the verification of declarative Web services composition processes using satisfiability solving (SAT). The need for the bounded model-checking approach stems from the nature of declarative processes as they are defined by only specifying the constraints that mark the boundary of the solution to the composition process. The proposed approach relies on using Event Calculus (EC) as the modeling formalism with a sound and complete EC to SAT encoding process. The use of EC as the modeling also formalism allows for a highly expressive approach for both the specification of composition model and for the specification of verification properties. Furthermore, as the conflict clauses returned by the SAT solver can be significantly large for complex processes and verification requirements, we propose a filtering criterion and defined patterns for identifying the clauses of interest for process verification.

With the rapid development of Web2.0 and its related technologies, Mashup services (i.e., Web applications created by combining two or more Web APIs) are becoming a hot research topic. The explosion... Show More

With the rapid development of Web2.0 and its related technologies, Mashup services (i.e., Web applications created by combining two or more Web APIs) are becoming a hot research topic. The explosion of Mashup services, especially the functionally similar or equivalent services, however, make services discovery more difficult than ever. In this paper, we present an approach to recommend Mashup services to users based on usage history and service network. This approach firstly extracts users' interests from their Mashup service usage history and builds a service network based on social relationships information among Mashup services, Web application programming interfaces (APIs) and their tags. The approach then leverages the target user's interest and the service social relationship to perform Mashup service recommendation. Large-scale experiments based on a real-world Mashup service dataset show that the authors' proposed approach can effectively recommend Mashup services to users with excellent performance. Moreover, a Mashup service recommendation prototype system is developed.