Service-Oriented Symbolic Computations

Author(s):  
Dana Petcu ◽  
Georgiana Macariu ◽  
Alexandru Cârstea ◽  
Marc Frîncu

Service-oriented computing is an interesting paradigm not only for building business applications but also for scientific applications requiring a loosely-coupled communication system between its components. In particular, scientific applications involving symbolic computations that are both computational and data intensive have proved in the last years to be adequate for implementation in service-oriented architectures, mainly due to the standards promoted for communications or service discovery. This chapter discusses the main issues and problems encountered in the transition from the classical symbolic computations based on stand-alone computer algebra systems towards service-oriented symbolic computations, such as building services from legacy codes, discover, compose and orchestrate services, standardize the exchange data formats. Moreover, several new approaches to solve at least partially these transition problems have been recently implemented, tested and are revealed in this chapter.

Author(s):  
Anton Michlmayr ◽  
Philipp Leitner ◽  
Florian Rosenberg ◽  
Schahram Dustdar

Service-oriented Architectures (SOA) and Web services have received a lot of attention from both industry and academia. Services as the core entities of every SOA are changing regularly based on various reasons. This poses a clear problem in distributed environments since service providers and consumers are generally loosely coupled. Using the publish/subscribe style of communication service consumers can be notified when such changes occur. In this chapter, we present an approach that leverages event processing mechanisms for Web service runtime environments based on a rich event model and different event visibilities. Our approach covers the full service lifecycle, including runtime information concerning service discovery and service invocation, as well as Quality of Service attributes. Furthermore, besides subscribing to events of interest, users can also search in historical event data. We show how this event notification support was integrated into our service runtime environment VRESCo and give some usage examples in an application context.


Author(s):  
Dimka Karastoyanova ◽  
Frank Leymann

The current trend in Service Oriented Computing (SOC) is to enable support for new delivery models of software and applications. These endeavours impose requirements on the resources and services used, on the way applications are created and on the QoS characteristics of the applications and the supporting infrastructure. Scientific applications on the other hand require improved robustness and reliability of the supporting Grid infrastructures where resources appear and disappear constantly. Enabling business model like Software as a Service (SaaS), Infrastructure as a Service (IaaS), and guaranteeing reliability of Grid infrastructures are requirements that both business and scientific application nowadays impose. The convergence of existing approaches from SOC and Grid Computing is therefore an obvious need. In this work we give an overview of the state-of-the-art of the overlapping research done in the area of SOC and Grid computing with respect to meeting the requirements of the applications in these two areas. We show that the requirements of business applications that already exploit service-oriented architectures (SOA) and the scientific application utilizing Grid infrastructures overlap. Due to the limited extent of cooperation between the two research communities the research results are either overlapping or diverging in spite of the similarities in requirements. Notably, some of the techniques developed in each area are needed but still missing in the other area and vice versa. We argue therefore that in order to enable an enterprise-strength service-oriented infrastructure one needs to combine and leverage the existing Grid and Service middleware in terms of architectures and implementations. We call such an infrastructure the Business Grid. Based on the Business Grid vision we focus in this work on presenting how reliability and robustness of the Business Grid can be improved by employing approaches for flexibility of service compositions. An overview and assessment of these approaches are presented together with recommendations for use. Based on the assumption that Grid services are Web services, these approaches can be utilized to improve the reliability of the scientific applications thus drawing on the advantages flexible workflows provide. This way we improve the robustness of scientific applications by making them flexible and hence improve the features of business applications that employ Grid resources and Grid service compositions to realize the SaaS, IaaS etc. delivery models.


2012 ◽  
pp. 799-820
Author(s):  
Dimka Karastoyanova ◽  
Frank Leymann

The current trend in Service Oriented Computing (SOC) is to enable support for new delivery models of software and applications. These endeavours impose requirements on the resources and services used, on the way applications are created and on the QoS characteristics of the applications and the supporting infrastructure. Scientific applications on the other hand require improved robustness and reliability of the supporting Grid infrastructures where resources appear and disappear constantly. Enabling business model like Software as a Service (SaaS), Infrastructure as a Service (IaaS), and guaranteeing reliability of Grid infrastructures are requirements that both business and scientific application nowadays impose. The convergence of existing approaches from SOC and Grid Computing is therefore an obvious need. In this work we give an overview of the state-of-the-art of the overlapping research done in the area of SOC and Grid computing with respect to meeting the requirements of the applications in these two areas. We show that the requirements of business applications that already exploit service-oriented architectures (SOA) and the scientific application utilizing Grid infrastructures overlap. Due to the limited extent of cooperation between the two research communities the research results are either overlapping or diverging in spite of the similarities in requirements. Notably, some of the techniques developed in each area are needed but still missing in the other area and vice versa. We argue therefore that in order to enable an enterprise-strength service-oriented infrastructure one needs to combine and leverage the existing Grid and Service middleware in terms of architectures and implementations. We call such an infrastructure the Business Grid. Based on the Business Grid vision we focus in this work on presenting how reliability and robustness of the Business Grid can be improved by employing approaches for flexibility of service compositions. An overview and assessment of these approaches are presented together with recommendations for use. Based on the assumption that Grid services are Web services, these approaches can be utilized to improve the reliability of the scientific applications thus drawing on the advantages flexible workflows provide. This way we improve the robustness of scientific applications by making them flexible and hence improve the features of business applications that employ Grid resources and Grid service compositions to realize the SaaS, IaaS etc. delivery models.


Author(s):  
Sonia Ben Mokhtar ◽  
Pierre-Guillaume Raverdy ◽  
Aitor Urbieta ◽  
Roberto Speicys Cardoso

The inherent heterogeneity of ambient computing environments and their constant evolution requires middleware platforms to manage networked components designed, developed, and deployed independently. Such management must also be efficient to cater for resource-constrained devices and highly dynamic situations due to the spontaneous appearance and disappearance of networked resources. For service discovery protocols (SDP), one of the main functions of service-oriented architectures (SOA), the efficiency of the matching of syntactic service descriptions is most often opposed to the fullness of the semantic approach. As part of the PLASTIC middleware, the authors present an interoperable discovery platform that features an efficient matching and ranking algorithm able to process service descriptions and discovery requests from both semantic and syntactic SDPs. To that end, the paper defines a generic, modular description language able to record service functional properties, potentially extended with semantic annotations. The proposed discovery platform leverages the advanced communication capabilities provided by the PLASTIC middleware to discover services in multi-network environments. An evaluation of the prototype implementation demonstrates that multi-protocols service matching supporting various levels of expressiveness can be achieved in ambient computing environments.


Author(s):  
Gerhard Austaller

The chapter “Ubiquitous Services and Business Processes” discussed the benefits for real time enterprises of service oriented architectures (SOA) in terms of reusability and flexibility. Web services are one incarnation of SOA. This chapter gives a brief introduction to SOA. It discusses the attributes that define SOA, the roles of the participants in a service oriented environment. The essence of SOA is that clients use services offered by a service provider to get a task done. For the moment we simplify service to “a software component with network connection”. Services are offered with a description at wellknown “places” (also called registries, repositories), where clients choose services according to their needs. The chapter discusses several approaches to describe services and to look for them. Moreover, some well-known systems, and also current research, are discussed.


Author(s):  
Giuseppe Di Modica ◽  
Orazio Tomarchio ◽  
Lorenzo Vita

Resource and service discovery in SOAs: A P2P oriented semantic approachAn intense standardization process is favouring the convergence of grids and Service Oriented Architectures (SOAs). One of the benefits of such technological convergence is that grid resources and applications can be virtualized by services and offered through the SOA paradigm. In the broad and interoperable scenarios enabled by the SOA, involving the participation of several grid infrastructures across many administrative domains, service discovery can be a serious issue. In this paper we present a P2P-based infrastructure that leverages semantic technologies to support a scalable and accurate service discovery process. The key concept of the presented idea is the creation of an overlay network organized in several semantic groups of peers, each specialized in answering queries pertaining to specific applicative domains. Groups are formed by clustering together peers offering services that are semantically related. The architecture details of the proposed solution are presented. A system prototype has also been implemented and validated through a case study deployed on the PlanetLab testbed.


Author(s):  
A. Vani Vathsala ◽  
Hrushikesha Mohanty

The success of the Internet and the ongoing globalization led to a demand for new solutions to meet the requirements for ITsystems. The paradigm of service-oriented and event-driven architecture with fine grained and loosely coupled services tries to cope with those needs. Service Oriented Architecture (SOA) and Event Driven Architecture (EDA) are two acknowledged architectures for the development of business applications and information systems, which have evolved separately over the years. Today both architectures are acknowledged, but their synergy is not. There are numerous benefits of having an architecture that supports coexistence between operations and events, and composition of services based on operation invocation and event triggering. As part of our ongoing research work, we have tried to analyze in this paper, the basic design of Event based systems, issues that have to be addressed when event based approach is used for composing and coordinating web services. Then we have specified the techniques available that handle these issues, and gave a comparative study on these techniques. Finally we have attempted to sort out the unhandled/ partially handled issues that could be addressed as part of our research.


Author(s):  
Arun Kumar ◽  
Vikas Agarwal

Distributed Systems of today have evolved from tightly coupled architectures such as CORBA and DCOM to loosely coupled service-oriented architectures such as Web Services. The success of such architectures depends upon availability of supporting functions such as security, systems management, service level agreements and development environments with associated tooling. An important management component of such an infrastructure is the metering and accounting for service usage which is essential for successful deployments in commercial environments. This paper explores the problem space and presents an architecture that addresses this need. We start by defining taxonomy of services from the perspective of usage metering, charging and business models. We discuss how service usage can be measured, aggregated and communicated in a uniform way. Finally, we report on a prototype design and implementation.


2010 ◽  
Vol 2 (4) ◽  
pp. 13-32 ◽  
Author(s):  
Sonia Ben Mokhtar ◽  
Pierre-Guillaume Raverdy ◽  
Aitor Urbieta ◽  
Roberto Speicys Cardoso

The inherent heterogeneity of ambient computing environments and their constant evolution requires middleware platforms to manage networked components designed, developed, and deployed independently. Such management must also be efficient to cater for resource-constrained devices and highly dynamic situations due to the spontaneous appearance and disappearance of networked resources. For service discovery protocols (SDP), one of the main functions of service-oriented architectures (SOA), the efficiency of the matching of syntactic service descriptions is most often opposed to the fullness of the semantic approach. As part of the PLASTIC middleware, the authors present an interoperable discovery platform that features an efficient matching and ranking algorithm able to process service descriptions and discovery requests from both semantic and syntactic SDPs. To that end, the paper defines a generic, modular description language able to record service functional properties, potentially extended with semantic annotations. The proposed discovery platform leverages the advanced communication capabilities provided by the PLASTIC middleware to discover services in multi-network environments. An evaluation of the prototype implementation demonstrates that multi-protocols service matching supporting various levels of expressiveness can be achieved in ambient computing environments.


2011 ◽  
Vol 8 (1) ◽  
pp. 21-40 ◽  
Author(s):  
Karin Becker ◽  
Jim Pruyne ◽  
Sharad Singhal ◽  
Andre Lopes ◽  
Dejan Milojicic

A major advantage of Service-Oriented Architectures (SOA) is composition and coordination of loosely coupled services. Because the development lifecycles of services and clients are de-coupled, multiple service versions must be maintained to support older clients. Typically versions are managed within the SOA by updating service descriptions using conventions on version numbers and namespaces. In all cases, the compatibility among services descriptions must be evaluated, which can be hard, error-prone and costly if performed manually, particularly for complex descriptions. In this paper, the authors describe a method to automatically determine when two service descriptions are backward compatible. The authors describe a case study to illustrate version compatibility information in a SOA environment and present initial performance overheads. By automatically exploring compatibility information, a) service developers can assess the impact of proposed changes; b) proper versioning requirements can be put in client implementations guaranteeing that incompatibilities will not occur during run-time; and c) messages exchanged in the SOA can be validated to ensure that only expected messages or compatible ones are exchanged.


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