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This paper reports our practical experience of benchmarking a complex System Biology Web Service, and investigates the instability of its behaviour and the delays induced by the communication medium. We present the results of our ...
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This paper reports our practical experience of benchmarking a complex System Biology Web Service, and investigates the instability of its behaviour and the delays induced by the communication medium. We present the results of our statistical data analysis and the distributions, describing and predicting the response time instability typical of Service-Oriented Architectures (SOAs) built over the Internet. Our experiment has shown that the request processing time of the target e-science Web Service has a higher instability than the network round trip time. It was found that the request processing time can be represented better than the network round trip time using a particular theoretical distribution, moreover the probability distribution series of the round trip time have characteristics make it really difficult to describe them theoretically. The paper concludes with discussing the lessons learnt about the analysis techniques to be used in such experiments, the validity of the data, the main causes of uncertainty and possible remedial action.
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The Service-Oriented Architecture (SOA) paradigm has been chosen by NC3B as the recommended method to achieve interoperability at the information infrastructure level within NATO. Current technologies to implement SOA were designe...
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The Service-Oriented Architecture (SOA) paradigm has been chosen by NC3B as the recommended method to achieve interoperability at the information infrastructure level within NATO. Current technologies to implement SOA were designed for civilian use over robust, high-bandwidth networks and consequently not designed to work over the disadvantaged grids that are employed at the military tactical level. This makes it hard to achieve interoperability among the Nations in the battle space. The disadvantaged grids that IST-090 considered are mobile ad-hoc networks that are characterized by line-of-sight connections, low bandwidth, intermittent availability, etcetera. IST-090 identified improvements to make SOA work while using disadvantaged grids and built demonstrations that show how the challenges that arise because of the use of disadvantaged grids in near-real-time, as is the case at the tactical level in military operations, can be mitigated. IST-090 used a concrete military scenario as a global context for the study. Areas of research included: efficient communication frameworks, mechanisms to reduce needed bandwidth and mechanisms to improve reliability. IST-090 specifically considered the following technologies: Web Services and Service Discovery, Data Distribution Services, Common Distributed Databases and Cross-layer design. The results demonstrated that SOA can be applied at lower levels than previously thought.
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To increase combat effectiveness by networking the warfighter and to easily modify and expand its existing network architecture, the United States Navy requires shipboard computer systems that are network-centric and service- base...
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To increase combat effectiveness by networking the warfighter and to easily modify and expand its existing network architecture, the United States Navy requires shipboard computer systems that are network-centric and service- based and that support open architectures. However, they are limited by the radio frequency bandwidth that is available for shipboard communications. As a result, some network applications must take priority over others. The current Navy prioritization scheme was not designed with the needs of the warfighter as the primary focus nor does it allow for dynamically changing priorities based on changing threats. A prioritization scheme is proposed that optimizes network performance based on warfighter needs. The scheme is developed using the Capabilities-Based Competency Assessment process introduced by Suttie and Potter (2008) applied to an air detect-to-engage scenario for a carrier strike group underway. A comparison is made between the proposed prioritization scheme and traditional Navy schemes using simulation. Results show our prioritization scheme consistently reduced latency and increased throughput for mission relevant applications. These improvements translate directly to more relevant information getting to decision-makers sooner, which leads to information superiority, ultimately enhancing warfighting capability.
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Web Services is a strong candidate to carry out the Service Oriented Architecture, SOA, which has been established for the future Command and Control System for the Swedish Armed Forces. A successful progress of the Web Services c...
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Web Services is a strong candidate to carry out the Service Oriented Architecture, SOA, which has been established for the future Command and Control System for the Swedish Armed Forces. A successful progress of the Web Services concept demands flexible ways for Web Services to cooperate and to jointly fulfill a task that is requested by a client. In some applications, the execution of the task is not completely specified beforehand, but could rather be referred to as 'best effort'. One example is information searches. To achieve trust in the outcome of the task, it is essential that the identities of the cooperating Web Services can be tracked in a secure way. This report describes an approach to securely track identities of the cooperating Web Services, subsequently invoked by chains of one-way messages. The model is based on a message structure, which the requesting client can use to iteratively build a hierarchic tree. The model facilitates flexibility and robustness. The main parts of the model have been implemented to verify its usefulness. The conclusion is that the model is readily implemented, but that prefabricated Web Services platforms are not the best choice for implementation.
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Achieving high dependability and fault-tolerance in service-oriented architecture (SOA) is an open problem. Exception handling is one of the powerful means for improving the quality of SOA. The paper discusses the results of exper...
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Achieving high dependability and fault-tolerance in service-oriented architecture (SOA) is an open problem. Exception handling is one of the powerful means for improving the quality of SOA. The paper discusses the results of experimental analysis of the SOA-specific exceptions and factors affecting availability and faulttolerance of Web Services, implemented using two development kits: JAX-RPC implementation at Sun Microsystems and IBM WebSphere Software Developer Kit for Web Services. We specifically focus on the results of exception propagation and performance analysis. Finally, applications of different error recovery strategies including backward, forward and enhanced forward error recovery, in the context of SOA are briefly discussed.
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This paper is concerned with providing the user with an efficient way to find information, specifically weather effects products within a Service Oriented Architecture. The work outlined in this paper pertains to searching and ran...
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This paper is concerned with providing the user with an efficient way to find information, specifically weather effects products within a Service Oriented Architecture. The work outlined in this paper pertains to searching and ranking weather effects products from the EVIS (Environmental Visualization) data provider. EVIS was a data provider to a Federated Search engine in the NCES (Network Centric Enterprise Services) ECB (Early Capabilities Baseline). Several off the shelf search solutions are examined and a custom search/relevance algorithm is discussed. This algorithm is based on the idea that searching weather products is more akin to a database search. The paper concludes with at a look at cross provider relevance and the complications that arise with a larger scale, growing SOA.
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Development of modern critical software requires stringent processes that are scalable, automated and support traceability between various artifacts. It is important that the processes ensure that all the development steps are ful...
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Development of modern critical software requires stringent processes that are scalable, automated and support traceability between various artifacts. It is important that the processes ensure that all the development steps are fully documented. This paper proposes a software engineering architecture that supports the development of critical software by enacting the development activities from a centralized cloud-based service, by storing all the development artifacts produced at all steps in a dedicated repository and by providing a general mechanism for supporting a repository of typical development steps (including, the ones supported by verification and analysis tools packaged as services). This extendable architecture makes use of all benefits the cloud technologies provide, including elasticity and per-demand cost, to help all system developers work together on a project and share processes, tools and artifacts. The paper introduces the general architecture, describes all its components, presents a proof-of-concept implementation, and briefly outlines a simple delegation example in which two organizations are involved in development to demonstrate how the implementation operates.
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NASA's Goddard Mission Services Evolution Center (GMSEC) ground system architecture has been in development since late 2001, has successfully supported eight orbiting satellites and is being applied to many of NASA's future missio...
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NASA's Goddard Mission Services Evolution Center (GMSEC) ground system architecture has been in development since late 2001, has successfully supported eight orbiting satellites and is being applied to many of NASA's future missions. GMSEC can be considered an event-driven service-oriented architecture built around a publish/subscribe message bus middleware. This paper briefly discusses the GMSEC technical approaches which have led to significant cost savings and risk reduction for NASA missions operated at the Goddard Space Flight Center (GSFC). The paper then focuses on the development and operational impacts of extending the architecture across multiple mission operations facilities.
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