Andrea Zisman

A Framework for Dynamic Service Discovery

Service discovery has been recognised as an important activity for service-based systems. In this paper we describe a framework for dynamic service discovery that supports the identification of service during the execution time of service-based systems. In the framework, services are identified based on structural, behavioural, quality, and contextual characteristics of a system represented in query languages. The framework supports both pull and push modes of query execution. In the approach, a service is identified based on the computation of distances between a query and a candidate service. A prototype tool has been implemented in order to illustrate and evaluate the framework. The paper also describes the results of a set of experiments that we have conducted to evaluate the work.

Behavioral models as service descriptions

Interface descriptions, while adequate for describing relatively simple or uniform functionality, are too abstract to properly describe entities as complex as e-commerce services or feature rich telecommunications services. The web services community has partially acknowledged this, as description languages like WSCL and OWL-S have enriched interface information with additional fragments of component semantics. In this paper, we naturally extend this progression by proposing that services be described by (abstract) executable specification behavioral models instead of, or in addition to, these other descriptive formalisms. Our argument is based on the observation that at least three capabilities, service discovery, validation, and execution monitoring, are enabled or fundamentally improved by this idea. In addition to overviewing OpenModel, our distributed modeling framework, as one possible basis for this approach, we also describe case studies that support our claims, and review the limitations of existing approaches.

Architecture-Driven Service Discovery for Service Centric Systems

Service discovery has been recognized as an important aspect in the development of service-centric systems, i.e., software systems which deploy Web services. To develop such systems, it is necessary to identify services that can be combined in order to fulfill the functionality and achieve quality criteria of the system being developed. In this paper, we present a framework supporting architecture-driven service discovery (ASD)—that is the discovery of services that can provide functionalities and satisfy properties and constraints of systems as specified during the design phase of the development lifecycle based on detailed system design models. Our framework assumes an iterative design process and allows for the (re-)formulation of design models of service-centric systems based on the discovered services. The framework is composed of a query extractor, which derives queries from behavioral and structural UML design models of service-centric systems, and a query execution engine that executes these queries against service registries based on graph matching techniques. The article describes a prototype tool that we have developed to demonstrate and evaluate our framework and the results of a set of preliminary experiments that we have conducted to evaluate it.

Proactive Runtime Service Discovery

In this paper we describe a framework that supports runtime service discovery in both pull and push modes. Our framework supports service discovery based on structural and behavioural models of services and applications, as well as quality and contextual constraints. In the approach, we use a proactive push mechanism in which services are identified in parallel to the execution of the system based on subscriptions of services and queries. A prototype tool has been implemented in order to illustrate and evaluate the framework.

UML-based service discovery framework

The development of service centric systems, i.e software systems constructed as compositions of autonomous services, has been recognised as an important approach for software system development. Recently, there has been a proliferation of systems which are developed, deployed, and consumed in this way. An important aspect of service centric systems is the identification of web services that can be combined to fulfill the functionality and quality criteria of the system being developed. In this paper we present the results of the evaluation of a UML-based framework for service discovery. This framework supports the identification of services that can provide the functionality and satisfy properties and constraints of service centric systems as specified during their design. Our approach adopts an iterative design process allowing for the (re-) formulation of the design models of service centric systems based on the discovered services. A prototype tool has been developed and includes (a) a UML integration module, which derives queries from behavioural and structural UML design models and integrates the results of the queries; and (b) a query execution engine, which performs queries against service registries based on similarity analysis.

Replacement policies for service-based systems

The need to change service-based systems during their execution time has been recognized as an important challenge in service oriented computing. There are several situations that may trigger changes in service-based systems such as unavailability or malfunctioning of services; changes in the functional, quality, or contextual characteristics of the services; changes in the context of the service-based system environment; emergence of new services; or changes in the requirements of the system. However, in order to support dynamic changes in service-based systems, it is necessary to have replacement policies describing what needs to be changed, and how and when the changes should be executed. In this paper, we describe replacement policies to support dynamic changes in service-based systems. These replacement policies are used in our service discovery framework that supports proactive identification of services in parallel to the execution of the system. A prototype tool has been implemented in order to illustrate and evaluate the framework. The results of some initial evaluation are also described in the paper.

UML-based Service Discovery Tool

The development of service centric systems has been recognised as an important approach for software system development. In this paper, we present a UML-based tool to identify services that can provide the functionality and satisfy properties and constraints of service centric systems specified during the design phase of the development of these systems and allows for the (re-) formulation of the design models based on the discovered services

Consistency Management of Financial XML Documents

In the financial domain a large number of inconsistent documents are produced every day. Up to now, many of the consistency management activities are executed manually, generating significant expense and operational risks. In this paper we present an approach for consistency management of financial XML documents. The approach includes the activities of consistency checking and consistency handling. It is based on consistency rules, used to express relationships among elements and documents, and resolution actions, used to restore the documents to a consistent manner. A prototype tool has been developed to demonstrate and evaluate the approach.