Mahdi Sargolzaei

Orchestrating web services using Reo: from circuits and behaviors to automatically generated code

We present a compositional construction of web services, using Reo and constraint automata as the main “glue” ingredients. Reo is a graphical and exogenous coordination language based on channels. We propose a framework that, taking as input the behavioral description of services (as constraint automata), their WSDL interfaces, and the description of their interaction in Reo, generates all the necessary Java code to orchestrate the services in practice. For each web service, we automatically generate a proxy that manages the communication between this service and the Reo circuit. Although we focus on web services, we can compose different kinds of service-oriented and component technologies at the same time (e.g., CORBA, RPC, WCF), by generating different proxies and connecting them to the same coordinator.

Semi-automated software service integration in virtual organisations

To enhance their business opportunities, organisations involved in many service industries are increasingly active in pursuit of both online provision of their business services (BSs) and collaborating with others. Collaborative Networks (CNs) in service industry sector, however, face many challenges related to sharing and integration of their collection of provided BSs and their corresponding software services. Therefore, the topic of service interoperability for which this article introduces a framework is gaining momentum in research for supporting CNs. It contributes to generation of formal machine readable specification for business processes, aimed at providing their unambiguous definitions, as needed for developing their equivalent software services. The framework provides a model and implementation architecture for discovery and composition of shared services, to support the semi-automated development of integrated value-added services. In support of service discovery, a main contribution of this research is the formal representation of services’ behaviour and applying desired service behaviour specified by users for automated matchmaking with other existing services. Furthermore, to support service integration, mechanisms are developed for automated selection of the most suitable service(s) according to a number of service quality aspects. Two scenario cases are presented, which exemplify several specific features related to service discovery and service integration aspects.

A framework for automated service composition in collaborative networks

This paper proposes a novel framework for automated software service composition that can significantly support and enhance collaboration among enterprises in service provision industry, such as in tourism insurance and e-commerce collaborative networks (CNs). Our proposed framework is founded on service oriented architecture (SOA) paradigm, in which software services implementing on-line business services that are provided by different enterprises, will be formally defined, using an extended BPMN notation to capture their semantics and behavior, as well as the WSDL notation to capture their syntax. Furthermore, with registering the syntax, semantics and behavior of these software services in a service repository at the CN, the task of service discovery in this framework can go far beyond the current practice, which comprise of service search by name, to the possibility of discovering by service behavior. The paper addresses enhancement of automated software service integration in CNs, through the application of the Reo coordination language, which is used to formalize interaction among the composed services. The main reason for using Reo in this context is that it supports separating the computations needed by software components in an integrated system from their interactions. The suggested framework provides more flexibility, adaptability, as well as cost-effectiveness in service composition, when supported in collaborative networks.

A Coopetition Space for Complex Product Specification

Due to peculiarities and complexities embedded in complex service-enhanced products, e.g. automated buildings, these products are one-of-a-kind, largely customized, and may involve a large number of competitive / cooperative multi-stakeholders. Life cycle of complex products typically includes a substantially long creation phase, followed by its operation and evolution phases that last over decades. Although, the majority of complex product components (e.g. equipment and services) are specified gradually and by varied stakeholders during its creation stage, further specifications are also provided later on to support its evolution. This paper addresses challenges in both specification of varied and numerous components, and managing these specifications thought-out the complex product life cycle. We address reusability, modularity, and federated sharing requirements in the coopetition space of complex product specification, and within the context of Virtual organizations Breeding Environments (VBEs). Our developed product specification system, which is already alpha tested, addresses these identified requirements, and is described and exemplified.

On service-enhanced product recommendation guiding users through complex product specification

Complex service-enhanced products such as solar power plants and intelligent buildings are one-of-a-kind and highly customized by nature. As such on one hand the specification of their sub-products and services involve a wide variety of competitive/cooperative stakeholders and on the other hand through different stages of their long life cycle, these specification are generated in different sessions and go through many iterations. These characteristics of complex products make the process of specifying their components difficult and time-consuming. We have previously defined the tools for specification of both sub-products and their enhancing services related to complex products [1], [2]. In this paper we introduce an approach for the use of a recommender system to assist designers of sub-products with reusing the existing specifications, as well as for recommending business services that can enhance the defined sub-products. Considering that multitudinous (hundreds to thousands) components present in complex products, their specifications cannot be accomplished without proper reuse of related existing specifications in the system, shared by different stakeholders. The introduced recommender system assists designers with their specification of new components, using the previously specified components in the system, and discovers/ranks those similar components, while matching the preferences and requirements set by the users.

C3Q: A Specification Model for Web Services Within Virtual Organizations

Generic representation of web services is targeted, in order to generate machine readable specification of business processes that run at each partner organization within the virtual organization (VO). A holistic and formal service specification model is defined that can then be used unambiguously for discovery of business services, i.e. for finding a suitable service available at the VO to perform a given task. Especially, the proposed model, called C3Q, augments the description of service by its behavioral specification. A light extension of the WSDL documents is represented to specify all aspects of C3Q. Finally, a GUI is implemented to assist users with the behavioral description of the VO services.

Service Oriented Collaborative Network Architecture

A service-oriented collaborative network (SOCN) supports collaboration among a network of organizations through their shared business services. SOCN in comparison with traditional collaborative networks, promotes and simplifies reusability and interconnection of shared software services, in a distributed manner. Our work contributes to comprehensive support of software service oriented collaboration among networked organizations enabling semi-automated service discovery, selection, and composition in collaborative environments. With the help of an organizational monitoring tool, we improve the accuracy of claimed characteristics based on non-functional criteria of services. The reference framework and implementation architecture are defined in this paper to support implementing SOCN.

A Tool for Behaviour-Based Discovery of Approximately Matching Web Services

We present a tool that is able to discover stateful Web Services in a database, and to rank the results according to a similarity score expressing the affinities between each of them and a user-submitted query. To determine these affinities, we take behaviour into account, both of the user’s query and of the services. The names of service operations, their order of invocation, and their parameters may differ from those required by the actual user, which necessitates using similarity scores, and hence the notion of soft constraints. The final tool is based on Soft Constraint Automata and an approximate bisimulation among them, modeled and solved as a Constraint Optimisation Problem.