Many enterprises nowadays use business processes, based on the BPEL standard, to achieve their goals. These are complex, often distributed, processes. Monitoring the execution of such processes for interesting patterns is critical for enforcing business policies and meeting efficiency and reliability goals. BP-Mon (Business Processes Monitoring) is a novel query language for monitoring business processes, that allows users to visually define monitoring tasks and associated reports, using a simple intuitive interface, similar to those used for designing BPEL processes. We describe here the BP-Mon language and its underlying formal model. We also present the language implementation and describe our novel optimization techniques. An important feature of the implementation is thatBP-Mon queries are translated to BPEL processes that run on the same execution engine as the monitored processes. Our experiments indicate that this approach incurs very minimal overhead, hence is a practical and efficient approach to monitoring. 1.

Abstract — Current approaches to service composition In this paper, we first describe and compare these range from industrial standards (like BPEL and OWL-S) to formal methods (like Petri nets and process algebras). In this paper, we survey a number of such approaches and compare them with respect to a carefully selected set of characteristics (like exception handling and quality approaches to service composition w.r.t. a selected set of main characteristics to assess their quality, much in the style of [49]. We then survey the increasing use of formal methods (mainly state-action models like Petri of services). We conclude that formal methods, often nets or process models like the π-calculus) to formally including tool support, are ideal to assist designers and developers because their use leads to increased confidence in the obtained compositions. specify, compose and verify service compositions, and also compare these w.r.t. the selected set of characteristics. Finally, we discuss the expected advantage of using

Abstract. Conversations provide an intuitive and simple model for analyzing interactions among composite web services. A conversation is the global sequence of messages exchanged among the peers participating to a composite web service. Interactions in a composite web service can be analyzed by investigating the temporal properties of its conversations. Conversations can be specified in a top-down or bottom-up manner. In a top-down conversation specification, the set of conversations is specified first, without specifying the individual behaviors of the peers. In a bottom-up conversation specification, on the other hand, behavior of each peer is specified separately and the conversation set is defined implicitly as the set of conversations generated by these peers. For both top-down and bottom-up specification approaches we are interested in the following: 1) Automatically verifying properties of conversations, and 2) Investigating the effect of asynchronous communication on the conversation behavior. These two issues are closely related since asynchronous

Choreography analysis has been a crucial problem in service oriented computing. Interactions among services involve message exchanges across organizational boundaries in a distributed computing environment, and in order to build such systems in a reliable manner, it is necessary to develop techniques for analyzing such interactions. Choreography conformance involves verifying that a set of services behave according to a given choreography specification that characterizes their interactions. Unfortunately this is an undecidable problem when services interact with asynchronous communication. In this paper we present techniques that identify if the interaction behavior for a set of services remain the same when asynchronous communication is replaced with synchronous communication. This is called the synchronizability problem and determining the synchronizability of a set of services has been an open problem for several years. We solve this problem in this paper. Our results can be used to identify synchronizable services for which choreography conformance can be checked efficiently. Our results on synchronizability are applicable to any software infrastructure that supports message-based interactions.

Abstract: Service oriented architectures foster evolution of enterprise information systems by supporting loose coupling and easy composition of services. Unfortunately, current approaches to service composition are inapplicable to services that share subservices or data. In this paper, we define overlapping orchestrations, analyse the problems that they pose to existing composition approaches and propose orchestration merging, a novel, interactive approach to composition of overlapping orchestrations based on their semantic. 1

Abstract. Interoperability has been broadly conceptualized as the ability of agents to work together. In open systems, the interoperability of agents is an important concern. A common way of achieving interoperability is by requiring agents to follow prescribed protocols in their interactions with others. In existing systems, agents must follow any protocol to the letter; in other words, they should exchange messages exactly as prescribed by the protocol. This is an overly restrictive constraint; it results in rigid, fragile implementations and curbs the autonomy of agents. For example, a customer agent may send a reminder to a merchant agent to deliver the promised goods. However, if reminders are not supported explicitly in the protocol they are enacting, then the reminder would be considered illegal and the transaction may potentially fail. This paper studies the interoperation of agents, dealing with their autonomy and heterogeneity in computational terms. 1

The new paradigm for distributed computing over the Internet is that of Web services. The goal of Web services is to achieve universal interoperability between applications by using standardized protocols and languages. One of the key ideas of the Web service paradigm is the ability of building complex and value-added service-based applications by composing preexisting services. For a service-based application, in addition to its functional requirements, Quality of service (QoS) requirements are important and deserve a special attention. In this paper, we introduce a discrete-event modeling approach for service-based application. This approach is oriented towards QoS assurance through discrete-event simulation. considered as an example of service aggregators [4]. Multiple and different services such as calling services (e.g., call forwarding and call barring), messaging services (e.g., text messaging and video messaging), and internet services (e.g., chat and e-mail) are brought together and offered via telephone. For an SBA, in addition to its functional requirements, Quality of Service (QoS) requirements are important and deserve a special attention. QoS requirements for SBAs include response time, throughput, availability and security [4, 5]. Being able to characterize SBAs based on QoS has three distinct advantages [6]: Keywords: Web Services, Service-based applications, QoS assurance, Discrete-event simulation.

Abstract. Communication is an essential aspect of services. Services do not only realize simple request-response scenarios, but increasingly implement complex and stateful communication protocols. Such a protocol specifies the order in which messages are sent and received by a service and is an essential part of a service description. Services are usually not executed in isolation, but as a collaboration which is composed of several services. The behavior of such a collaboration is not only determined by the communication protocol of each participating service, but also by the way messages are exchanged. A communication model specifies the properties of the message channels between the services and defines the way how messages are sent and received. This paper studies and classifies several dimensions of communication models and describes their impact to the behavior of service compositions. 1

Quality related aspects relevant for service-based applications cover a broad field of research, including work on quality modeling, QoS and SLA negotiation, as well as constructive and analytical quality assurance (like testing, monitoring and static analysis). This deliverable provides a survey of this broad field of “service quality ” and identifies the key areas where research contributions are currently available. Based on this survey of the state of the art, important and emerging research challenges are identified that could be pursued in the future in order to close several of the gaps which emerge from the current state of the art on “service quality”. Copyright © 2008 by the S-Cube consortium – All rights reserved.

One of the key ideas behind the Web service technology is the ability to compose pre-existing services and systems into new distributed business processes and applications. The quality and the correctness of the composition requires continuous analysis of its behavior and validation of various requirements of the stakeholders, introducing new challenges that are peculiar to the Service-Oriented Architecture. In this work we present a formal analysis framework that allows for the verification of Web service composition facing these challenges in a rigorous and structured way.