Context constraint integration and validation in dynamic web service compositions

System architectures that cross organisational boundaries are usually implemented based on Web service technologies due to their inherent interoperability benets. With increasing exibility requirements, such as on-demand service provision, a dynamic approach to service architecture focussing on composition at runtime is needed. The possibility of technical faults, but also violations of functional and semantic constraints require a comprehensive notion of context that captures composition-relevant aspects. Context-aware techniques are consequently required to support constraint validation for dynamic service composition. We present techniques to respond to problems occurring during the execution of dynamically composed Web services implemented in WS-BPEL. A notion of context { covering physical and contractual faults and violations { is used to safeguard composed service executions dynamically. Our aim is to present an architectural framework from an application-oriented perspective, addressing practical considerations of a technical framework

Framework de Interoperabilidad para Sistemas de Comando y Control : FISiCO

La interoperabilidad en sistemas empresariales es un tema que se ha puesto en boga desde hace un tiempo. La necesidad de integración de sistemas legacy sigue presentando desafíos para los profesionales de sistema. Particularmente, en sistemas de comando y control (C2) para aplicaciones militares, este tema se potencia dado los requerimientos no funcionales adicionales que se presentan. Además de la interoperabilidad a nivel negocio para integrar a sistemas de software y hardware complejos que exceden a los sistemas empresariales, estos sistemas necesitan arquitecturas robustas resistentes a fallos, de alto rendimiento y con niveles de seguridad extra. FISiCO2 propone una arquitectura técnica que brinda robustez, seguridad e interoperabilidad entre sistemas complejos, dividiendo el problema en cinco capas que dan soporte a los distintos requerimientos de manera desacoplada y transparente. La línea de investigación rectora tiene como objetivo el desarrollo, despliegue y prueba de FISiCO2, para lograrlo se divide en tres sub-líneas: (1) sistemas Peer to Peer (P2P), (2) sistemas de integración empresariales orientados a servicios y (3) estándares, protocolos y arquitecturas distribuidas para las aplicaciones de negocios en sistemas de C2.Eje: Procesamiento distribuido y paraleloRed de Universidades con Carreras en Informática (RedUNCI

Framework de Interoperabilidad para Sistemas de Comando y Control : FISiCO

La interoperabilidad en sistemas empresariales es un tema que se ha puesto en boga desde hace un tiempo. La necesidad de integración de sistemas legacy sigue presentando desafíos para los profesionales de sistema. Particularmente, en sistemas de comando y control (C2) para aplicaciones militares, este tema se potencia dado los requerimientos no funcionales adicionales que se presentan. Además de la interoperabilidad a nivel negocio para integrar a sistemas de software y hardware complejos que exceden a los sistemas empresariales, estos sistemas necesitan arquitecturas robustas resistentes a fallos, de alto rendimiento y con niveles de seguridad extra. FISiCO2 propone una arquitectura técnica que brinda robustez, seguridad e interoperabilidad entre sistemas complejos, dividiendo el problema en cinco capas que dan soporte a los distintos requerimientos de manera desacoplada y transparente. La línea de investigación rectora tiene como objetivo el desarrollo, despliegue y prueba de FISiCO2, para lograrlo se divide en tres sub-líneas: (1) sistemas Peer to Peer (P2P), (2) sistemas de integración empresariales orientados a servicios y (3) estándares, protocolos y arquitecturas distribuidas para las aplicaciones de negocios en sistemas de C2.Eje: Procesamiento distribuido y paraleloRed de Universidades con Carreras en Informática (RedUNCI

A survey using constraints to decision-making for fault tolerance in Business processes

Sometimes the business processes do not work how it is expected. In these cases, a diagnosis process has to be executed to determine the responsible activity or activities of the fault in order to substitute it or them for a correct activity. The aim of this paper is describe the necessary steps to find out another service that can replace it in an efficient way. In order to automate the search and substitution of activities, we propose to describe the functionality of the tasks using constraints, making easier the determination of the possible activities that could substitute everyone faulty activities in the business process. In this paper, it is also analyzed how to adapt the communication protocol with XML messages to a behavior described using constraints.Junta de Andalucía P08-TIC-04095Ministerio de Ciencia y Tecnología TIN2009-1371

Design and Implementation of a Byzantine Fault Tolerance Framework for Web Services

Many Web services are expected to run with high degree of security and dependability. To achieve this goal, it is essential to use a Web services compatible framework that tolerates not only crash faults, but Byzantine faults as well, due to the untrusted communication environment in which the Web services operate. In this paper, we describe the design and implementation of such a framework, called BFT-WS. BFT-WS is designed to operate on top of the standard SOAP messaging framework for maximum interoperability. It is implemented as a pluggable module within the Axis2 architecture, as such, it requires minimum changes to the Web applications. The core fault tolerance mechanisms used in BFT-WS are based on the well-known Castro and Liskov’s BFT algorithm for optimal efficiency. Our performance measurements confirm that BFT-WS incurs only moderate runtime overhead considering the complexity of the mechanisms

Reusable and Extensible Fault Tolerance for RESTful Applications

Abstract—Despite the simplicity and scalability benefits of REST, rendering RESTful web applications fault-tolerant requires that the programmer write vast amounts of non-trivial, ad-hoc code. Network volatility, HTTP server errors, service outages—all require custom fault handling code, whose effective implementation requires considerable programming expertise and effort. To provide a systematic and principled ap-proach to handling faults in RESTful applications, we present FT-REST—an architectural framework for specifying fault tolerance functionality declaratively and then translating these specifications into platform-specific code. FT-REST encapsu-lates fault tolerance strategies in XML-based specifications and compiles them to modules that reify the requisite fault tolerance. To validate our approach, we have applied FT-REST to enhance several realistic RESTful applications to withstand the faults described in their FT-REST specifications. As REST is said to apply verbs (HTTP commands) to nouns (URIs), FT-REST enhances this conceptual model with adverbs that render REST reliable via reusable and extensible fault tolerance. Keywords-fault tolerance, web services, REST, software reusability, software extensibilit

A Light Weight Fault Tolerance Framework for Web Services

The increased usage of web services by many of the corporate industries to exchange their critical information over World Wide Web has directly impacted the need for high availability of web services. So in this work of ours we designed and developed a light weight fault tolerance framework for web services, by strictly biding ourselves to the design specifications of web services. We developed our framework by extending the open source implementation of Web services reliable messaging specifications. Our framework provides fault tolerance capability using the replication strategy, and can easily be reverted back to basic point to point reliable message specifications implementation dynamically upon availability of resources. We used a customized consensus solving algorithm to achieve and maintain consistency among the replicated systems. The message patterns that are used to exchange the data are very much bided to the message specifications of web services. Our framework does not use any proprietary protocols for transmission of messages over the network. We also carefully tuned our framework for enhanced performance by techniques like batching, and proved from our performance results that our framework is optimal and has very less run time overhea

A Light Weight Fault Tolerance Framework for Web Services

The increased usage of web services by many of the corporate industries to exchange their critical information over World Wide Web has directly impacted the need for high availability of web services. So in this work of ours we designed and developed a light weight fault tolerance framework for web services, by strictly biding ourselves to the design specifications of web services. We developed our framework by extending the open source implementation of Web services reliable messaging specifications. Our framework provides fault tolerance capability using the replication strategy, and can easily be reverted back to basic point to point reliable message specifications implementation dynamically upon availability of resources. We used a customized consensus solving algorithm to achieve and maintain consistency among the replicated systems. The message patterns that are used to exchange the data are very much bided to the message specifications of web services. Our framework does not use any proprietary protocols for transmission of messages over the network. We also carefully tuned our framework for enhanced performance by techniques like batching, and proved from our performance results that our framework is optimal and has very less run time overhea