Tammo van Lessen

BPEL for semantic web services (BPEL4SWS)

In this paper we present BPEL for Semantic Web Services (BPEL4SWS) - a language that facilitates the orchestration of Semantic Web Services using a process based approach. It is based on the idea of WSDL-less BPEL and enables describing activity implementations semantically which increases the flexibility of business processes. Following an approach that uses a set of composable standards and specifications, BPEL4SWS is independent of any Semantic Web Service framework. It can be used to compose Semantic Web Services, traditional Web Services and a mix of them.

SENTINEL: a semantic business process monitoring tool

Business Activity Monitoring (BAM) aims to support the real-time analysis of business processes in order to improve the speed and effectiveness of business operations. Providing a timely, integrated high-level view on the evolution and well-being of business activities within enterprises constitutes a highly valuable analytical tool for monitoring, managing and hopefully enhancing businesses. However, the degree of automation currently achieved cannot support the level of reactivity and adaptation demanded by businesses. We argue that the fundamental problem is that moving between the business level and the IT level is insufficiently automated and suggest an extensive use of semantic technologies as a solution. In particular, we present SENTINEL a Semantic Business Process Monitoring tool that advances the state of the art in BAM by making extensive use of semantic technologies in order to support the integration and derivation of business level knowledge out of low-level audit trails generated by IT systems.

Virtualizing Services and Resources with ProBus: The WS-Policy-Aware Service and Resource Bus

A fundamental principle of service oriented architectures is the decoupling of service requesters and service providers to enable late binding of services at deployment time or even dynamic binding of services at runtime.This is important in enterprise settings, where different services that implement business functions in critical business processes are dynamically chosen based on availability or price. The same problem also applies to dynamic Grid environments where resources need to be dynamically chosen based on availability and other non-functional properties. The WS-Policy framework describes how policies for both providers and requesters are specified to allow the selection of services based on these policies. Existing approaches, using WS-Policy,have drawbacks by placing the burden of the service selection partially on the client. In this paper we present an extended enterprise service bus that allows service clients to submit policies to which service providers need to comply with together in one message with the service invocation request. We show how these policies are evaluated in the bus and how policies are defined for not only stateless services, but also stateful resources.

An Execution Engine for Semantic Business Processes

In this paper we present the architecture and design of an extended BPEL engine that implements the operational semantics of BPEL4SWS. BPEL4SWS is an extension of the BPEL language with support for Semantic Web Service concepts like mediation and semantic descriptions of activity implementations. We describe the basic communication scenarios of processes with services and the interaction between the engine components involved in the execution of BPEL4SWS processes. The presented prototype is based on the open source BPEL engine Apache ODE, features improved configurability and facilitates the definition of additional BPEL extensions with minimal development effort.

Conversational Web Services: leveraging BPELlight for expressing WSDL 2.0 message exchange patterns

Message exchange patterns provide means to define the message flow of a service and how these messages are related in an abstract and reusable manner. They are an integral part of WSDL 2.0 and allow defining operations that have a message exchange beyond request-response. They reduce the impedance mismatch between imperative programming and message orientation while emphasising the message orientated nature of Web Services. Whereas BPEL defines a flow between Web Service operations, BPELlight is an appropriate candidate to define the flow within operations since it abstracts from WSDL. In this article we use BPELlight to capture complex message exchanges. We show how its partner model can be used to not only define bilateral message exchanges but also those conversations that involve different partner types and/or multiple instances of such partners. Therefore we introduce first-class mechanisms to store, query and thus distinguish addressing information related to multiple partner instances. In addition, we increase reusability by allowing recursive definitions of such models. Thus, we enable modelling message exchange patterns that capture business logic in a reusable manner on an abstract level like for instance a request for bid scenario or a business transaction for purchase. Finally, we show how such patterns can be generically mapped to transport protocols.

Interaction Choreography Models in BPEL: Choreographies on the Enterprise Service Bus

Interactions between services may be globally captured by choreographies. We introduce BPELgold supporting modeling interaction choreography models using BPEL. We show the usage of BPELgold in an enterprise service bus to ensure an executed message exchange complies with a pre-defined choreography.

Modeling Test Cases in BPMN for Behavior-Driven Development

Testing large-scale process integration solutions is complex and cumbersome. To tackle this problem, researchers employed behavior-driven development. They used the Business Process Model and Notation language to model domain-specific test cases. These test cases can be understood by both developers and business stakeholders and can be executed automatically.

BPELscript: A Simplified Script Syntax for WS-BPEL 2.0

Business processes are usually modeled using graphical notations such as BPMN. As a first step towards execution as workflow, a business process is transformed to an abstract WS-BPEL process. Technical details required for execution are added by an IT expert. While IT experts expect Java-like syntax for programs, WS-BPEL requires processes to be expressed in XML. This paper introduces BPELscript as a new syntax for WS-BPEL aiming to reduce the barrier for IT experts to use WS-BPEL by providing a JavaScript-inspired syntax.

WSMO/X in the context of business processes: improvement recommendations

Purpose – Service‐oriented architecture (SOA) is an architecture paradigm targeting integration of applications within and across enterprise boundaries. It has gathered research and industry acceptance and has given an enormous impetus to the business process management technology. Web service (WS) technology is one implementation of the SOA paradigm. It enables seamless integration of new and legacy applications through a stack of standardized composable specifications. WS orchestration is facilitated by the Business Process Execution Language which provides a recursive service composition model. While the programming model the WS technology provides is very flexible, a major deficiency is the need to discover services implementing a particular abstract interface, whereas functional similarities of services are disregarded. The Semantic Web Service technologies, like Web Service Modelling Ontology (WSMO) and Web Ontology Language for Services have been developed with the purpose of eliminating these defi...

Composing services on the grid using BPEL4SWS

Service composition on the Grid is a challenging task as documented in existing research work. Even though there are initial attempts to use the Business Process Execution Language (BPEL) to compose services on the Grid, still there is a significant lack of flexibility and reusability needed in scientific applications. In this paper we present BPEL for Semantic Web Services (BPEL4SWS) - a language that facilitates the orchestration of Grid Services exposed as traditional Web Services or Semantic Web Services using a process-based approach. It is based on the idea of WSDL-less BPEL and incorporates semantic descriptions of process activity implementations which increases the flexibility of business workflows as well as scientific workflows. Following an approach that uses a set of composable standards and specifications, BPEL4SWS is independent of any Semantic Web Service framework and therefore can also utilize any kind of Semantic Grid services. The advantages of BPEL4SWS are: (1) compliance with standards, (2) independence on service technologies, (3) applicability for both business applications as well as scientific workflows that use Grid services, (4) improved flexibility of processes.