A generic query model for the unified discovery of heterogeneous services

In this paper, we propose Proteus, a generic query model for the discovery of operations offered by heterogeneous services. We demonstrate the need for such a model, and show how it unifies the task of service discovery through abstractions, which allow for the technology-independent formulation of service advertisements, queries, and query responses. On top of these generic elements, we build an intuitive, fuzzy-based query evaluation mechanism that supports the service matchmaking process by employing and appropriately combining existing similarity metrics. Thanks to the generality of Proteus, it is possible to seamlessly accommodate the discovery of operations provided by various types of services without the need of changing the existing service infrastructure. Thus, our approach is applicable to a variety of settings ranging from traditional web services to service-oriented grids, peer-to-peer networks, geospatial information systems, and so on. Overall, compared to the existing query models supported by standard service discovery technologies, our approach is marked by openness, flexibility, and improved performance in terms of precision and recall. The feasibility and efficiency of Proteus are verified by a series of experiments. © 2008-2012 IEEE

Semantically Enhanced Discovery of Heterogeneous Services

Abstract: Industrial application development approaches are striving for solutions that promote the rapid development of flexible and adaptable systems and the exploitation of legacy systems and resources. The Service-oriented Development (SOD) paradigm, a current trend in software development, could be beneficial to industrial application development approaches. However, the heterogeneity in existing standards and protocols for the discovery of the various service types is an obstacle for the use of SOD in industry. This paper addresses this issue by proposing a solution that supports the unified discovery of heterogeneous services and thus supporting the use of SOD in industry. The proposed solution comprises a generic service model (GeSMO), which facilitates the specification of heterogeneous services, a query language called Unified Service Query Language (USQL), based on GeSMO, which facilitates the unified discovery of heterogeneous services within heterogeneous service registries and a query engine called USQL Engine, that enables the execution of queries described in terms of the USQL, upon heterogeneous service registries

Semantically enhanced discovery of heterogeneous services

Industrial application development approaches are striving for solutions that promote the rapid development of flexible and adaptable systems and the exploitation of legacy systems and resources. The Service-oriented Development (SOD) paradigm, a current trend in software development, could be beneficial to industrial application development approaches. However, the heterogeneity in existing standards and protocols for the discovery of the various service types is an obstacle for the use of SOD in industry. This paper addresses this issue by proposing a solution that supports the unified discovery of heterogeneous services and thus supporting the use of SOD in industry. The proposed solution comprises a generic service model (GeSMO), which facilitates the specification of heterogeneous services, a query language called Unified Service Query Language (USQL), based on GeSMO, which facilitates the unified discovery of heterogeneous services within heterogeneous service registries and a query engine called USQL Engine, that enables the execution of queries described in terms of the USQL, upon heterogeneous service registries

Discovering web services and JXTA peer-to-peer services in a unified manner

Web services constitute the most prevailing instantiation of the service-oriented computing paradigm. Recently however, representatives of other computing technologies, such as peer-to-peer (p2p), have also adopted the service-oriented approach and expose functionality as services. Thus the service-oriented community could be greatly assisted, if these heterogeneous services were integrated and composed. A key towards achieving this integration is the establishment of a unified approach in service discovery. In this paper, we describe some features of a unified service query language and focus on its associated engine, which is used to discover web and p2p services in a unified manner. We exemplify how our unified approach is applied in the case of web and p2p service discovery in UDDI and JXTA, respectively. Additionally, we demonstrate how our service search engine is able to process heterogeneous service advertisements and thus to exploit the advertised syntactic, semantic, and quality-of-service properties during matchmaking. © 2006 Springer-Verlag

Decentralized enactment of BPEL processes

This article presents BPELcube, a framework comprising a scalable architecture and a set of distributed algorithms, which support the decentralized enactment of BPEL processes. In many application domains, BPEL processes are long-running, involve the exchange of voluminous data with external Web services, and are concurrently accessed by large numbers of users. In such context, centralized BPEL process execution engines pose considerable limitations in terms of scalability and performance. To overcome such problems, a scalable hypercube peer-to-peer topology is employed by BPELcube in order to organize an arbitrary number of nodes, which can then collaborate in the decentralized execution and monitoring of BPEL processes. Contrary to traditional clustering approaches, each node does not fully take charge of executing the whole process; rather, it contributes to the overall process execution by running a subset of the process activities and maintaining a subset of the process variables. Hence, the hypercube-based infrastructure acts as a single execution engine, where workload is evenly distributed among the participating nodes in a fine-grained manner. An experimental evaluation of BPELcube and a comparison with centralized and clustered BPEL engine architectures demonstrate that the decentralized approach yields improved process execution times and throughput. © 2014 IEEE

Decentralized and Energy-Efficient Workload Management in Enterprise Clouds

We present a decentralized approach towards scalable and energy-efficient management of virtual machine (VM) instances that are provisioned by large, enterprise clouds. In our approach, the computation resources of the data center are effectively organized into a hypercube structure. The hypercube seamlessly scales up and down as resources are either added or removed in response to changes in the number of provisioned VM instances. Without supervision from any central components, each compute node operates autonomously and manages its own workload by applying a set of distributed load balancing rules and algorithms. On one hand, underutilized nodes attempt to shift their workload to their hypercube neighbors and switch off. On the other, overutilized nodes attempt to migrate a subset of their VM instances so as to reduce their power consumption and prevent degradation of their own resources, which in turn may lead to SLA violations. In both cases, the compute nodes in our approach do not overload their counterparts in order to improve their own energy footprint. An evaluation and comparative study of the proposed approach provides evidence of its merits in terms of elasticity, energy efficiency, and scalability, as well as of its feasibility in the presence of high workload rates. © 2013 IEEE

Interoperability among heterogeneous services: The case of integration of P2P services with web services

Service-oriented computing (SOC) has been marked as the technology trend that caters for interoperability among the components of a distributed system. However, the emergence of various incompatible instantiations of the SOC paradigm, e.g. Web or peer-to-peer services (P2P), and the divergences encountered within each of these instantiations state clearly that interoperability is still an open issue, mainly due to its multi-dimensional nature. In this paper we address the interoperability problem by first presenting its multiple dimensions and then by describing a conceptual model called generic service model (GeSMO), which can be used as a basis for the development of languages, tools and mechanisms that support interoperability. We then illustrate how GeSMO has been utilized for the provision of a P2P service description language and a P2P invocation mechanism which leverages interoperability between heterogeneous P2P services and between P2P services and Web services. Copyright © 2008, IGI Global

Quantified matchmaking of heterogeneous services

As the service-oriented computing paradigm and its related technologies mature, it is expected that electronic services will continue to grow in numbers. In such a setting, the course of service discovery could yield many alternative yet heterogeneous services which, by all means, may be of different type and moreover distinguished by their quality characteristics. To come through such situations and ease the task of service selection, service search engines need to be powered by an efficient matchmaking mechanism, which will abstract requesters from service heterogeneity and provide them with the means for choosing the service that best fits their requirements, among a wide set of services with similar functionally. In this paper, we present an efficient service matchmaking algorithm, which facilitates the task of heterogeneous service selection, whilst combining and exploiting the syntactic, semantic, and Quality-of-Service (QoS) properties contained in service advertisements. © Springer-Verlag Berlin Heidelberg 2006