Simple resource specification, resource selection, and effective binding are critical capabilities for Grid middleware. We describe the Virtual Grid, an abstraction for providing these capabilities complex resource environments. Elements of the Virtual Grid include a novel resource description language (vgDL) and a resource selection and binding component (vgFAB), which accepts a vgDL specification and returns a Virtual Grid, that is, a set of selected and bound resources. The goals of vgFAB are efficiency, scalability, robustness to high resource contention, and the ability to produce results with quantifiable high quality. We present the design of vgDL, showing how it captures application-level resource abstractions using resource aggregates and connectivity amongst them. We present and evaluate a prototype implementation of vgFAB. Our results show that resource selection and binding for virtual grids of 10,000’s of resources can scale up to grids with millions of resources, identifying good matches in less than one second. Further, these matches have quantifiable quality, enabling applications to have high confidence in the results. We demonstrate the effectiveness of our combined selection and binding approach in the presence of resource contention, showing that robust selection and binding can be achieved at moderate cost. 1.

Abstract — Service composition allows future multimedia services to be automatically composed from atomic service components based on user’s dynamic service requirements. Previous work falls short for distributed multimedia service composition in terms of scalability, flexibility and qualityof-service (QoS) management. In this paper, we present a fully decentralized service composition framework, called SpiderNet, to address the challenges. SpiderNet provides statistical multi-constrained QoS assurances and load balancing for service composition. SpiderNet supports directed acyclic graph composition topologies and exchangeable composition orders. We have implemented a prototype of SpiderNet and conducted experiments on both wide-area networks and simulation testbed. Our experimental results show the feasibility and efficiency of the SpiderNet service composition framework.

In this paper we study the problem of multimedia streaming and transcoding in P2P systems. We propose a multimedia streaming architecture in which transcoding services coordinate to transform the streaming data into different formats and adapt to both the QoS requirements of the applications and to the availability of the system resources. Our techniques are entirely distributed, use only local knowledge and scale well with the size of the system. Extensive simulation results validate the performance of our approach.

Abstract. Many emerging on-line data analysis applications require applying continuous query operations such as correlation, aggregation, and filtering to data streams in real-time. Distributed stream processing systems allow in-network stream processing to achieve better scalability and quality-of-service (QoS) provision. In this paper we present Synergy, a distributed stream processing middleware that provides sharing-aware component composition. Synergy enables efficient reuse of both data streams and processing components, while composing distributed stream processing applications with QoS demands. Synergy provides a set of fully distributed algorithms to discover and evaluate the reusability of available data streams and processing components when instantiating new stream applications. For QoS provision, Synergy performs QoS impact projection to examine whether the shared processing can cause QoS violations on currently running applications. We have implemented a prototype of the Synergy middleware and evaluated its performance on both PlanetLab and simulation testbeds. The experimental results show that Synergy can achieve much better resource utilization and QoS provision than previously proposed schemes, by judiciously sharing streams and processing components during application composition.

Discovering and acquiring appropriate, complex resource collections in large-scale distributed computing environments is a fundamental challenge and is critical to application performance. This paper presents a new formulation of the resource selection problem and a new solution to the resource selection and binding problem called integrated selection and binding. Composition operators in our resource description language and efficient data organization enable our approach to allocate complex resource collections efficiently and effectively even in the presence of competition for resources. Our empirical evaluation shows that the integrated approach can produce solutions of significantly higher quality at higher success rate and lower cost than the traditional separate approach. The success rate of the integrated approach can tolerate as much as 15%-60 % lower resource availability than the separate approach. Moreover, most requests have at least the 98 th percentile rank and can be served in 6 seconds with a population of 1 million hosts. 1.

Context aware applications respond and adapt to changes in the computing environment. For example, they may react when the location of the user or the capabilities of the device used change. Despite the increasing importance and popularity of such applications, advances in application models to support their development have not kept up. Legacy application design models, which embed contextual dependencies in the form of if-then rules specifying how applications should react to context changes, are still widely used. Such models are impractical to accommodate the large variety of possibly even unanticipated context types and their values. This dissertation proposes a new application model for building context aware applications, considering them as dynamically composed sequences of calls to services, software components that perform well-defined computational operations and export open interfaces through which they can be invoked. This work employs goal-oriented inferencing from planning technologies for selecting the services and assembling the sequence of their execution, allowing different compositions

Abstract — This paper describes Service Clouds, a distributed infrastructure designed to facilitate rapid prototyping and deployment of services that enhance communication performance, robustness, and security. The infrastructure combines adaptive middleware functionality with an overlay network substrate in order to support dynamic instantiation and reconfiguration of services. The Service Clouds architecture includes a collection of lowlevel facilities that can be either invoked directly by applications or used to compose more complex services. After describing the Service Clouds architecture, we present results of two experimental case studies conducted on the PlanetLab Internet testbed, the first to improve throughput of bulk data transfer, and the second to enhance the robustness of multimedia streaming. I.

In pervasive computing, devices or peers may implement or compose services using services from other devices or peers, and may use components from various sources. A composition trust binding is a prescriptive set of rules which defines the combination of allowable components for a particular service or application. Composition trust bindings can be used to protect both the service invocation path as well as the content handling path. The subsidiary relationships addressed by a composition trust binding are typically transparent today, but represent potential security exposure in pervasive computing systems because the subsidiary services or components may have security vulnerabilities. We define the composition trust binding and illustrate its use in the context of rights management and distributed search in personal content publishing. We compare this approach to existing authentication and authorization methods in service composition. 1.

Abstract. We recently introduced Service Clouds, a distributed infrastructure designed to facilitate rapid prototyping and deployment of autonomic communication services. In this paper, we propose a model that extends Service Clouds to the wireless edge of the Internet. This model, called Mobile Service Clouds, enables dynamic instantiation, composition, configuration, and reconfiguration of services on an overlay network to support mobile computing. We have implemented a prototype of this model and applied it to the problem of dynamically instantiating and migrating proxy services for mobile hosts. We conducted a case study involving data streaming across a combination of PlanetLab nodes, local proxies, and wireless hosts. Results are presented demonstrating the effectiveness of the prototype in establishing new proxies and migrating their functionality in response to node failures. 1

Abstract. Multimedia Content distribution is playing an increasingly prominent role in the Internet today, with a proliferation of diverse services and delivery mechanisms. Due to this increasing heterogeneity the management of next generation content networks is becoming increasingly complex. This paper presents Juno, a configurable component-based middleware designed to address the divergent nature of modern content networking. In Juno, functionality is separated into pluggable components that can be dynamically attached, detached and deployed, allowing the middleware to be specialised and adapted for different applications and environments. To demonstrate how functionality from (existing) content distribution networks can be realised through the middleware, an application operating over BitTorrent and Pastry has been developed using Juno. Through this, Juno is evaluated by looking at functional, non-functional and performance aspects of the framework.