The virtual region-based P2P architecture was provided in this paper, which extended the proximity concept in overlay network. By virtual region it meant various related factors should be integrated into the design of...
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ISBN:
(纸本)3540380914
The virtual region-based P2P architecture was provided in this paper, which extended the proximity concept in overlay network. By virtual region it meant various related factors should be integrated into the design of P2P topology, such as peer interest, peer locality, and heterogeneity in peer capacity etc. But, the shared contents in P2P are vast and miscellaneous, it is very difficult to recognize the interest similarity among peers, dynamically form the interest region and direct peer to appropriate interest region. In this paper, the Jensen-Shannon Divergence (JSD) was used to characterize interest/semantic similarity among peers, and the interest region formation and location mechanism based on Dynamic Interest Landmark (DIL) was offered to facilitate to dynamically guide peers to join the appropriate interest region corresponding to peers' content semantic. Considering that interest region is composed of geographically sporadic peers, each interest region was organized according to peer proximity in underlying infrastructure. The theoretical and simulated results illustrated that our architecture can significantly reduce the query overhead, and improve the search performance.
QoS management has been extensively studied in network-based multimedia applications. However, its application to Web services is very recent In this paper, we present WS-QoSM, it Web services QoS management architect...
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ISBN:
(纸本)9781424406739
QoS management has been extensively studied in network-based multimedia applications. However, its application to Web services is very recent In this paper, we present WS-QoSM, it Web services QoS management architecture capable of supporting at runtime the QoS management operations, QoS provisioning and assurance in delivering Web services. Our proposed architecture is based on the commonly used notion of QoS brokerage service to mediate between service requesters and service providers. Its responsibilities include performance monitoring of Web services, implementation of Web service selection policies, and negotiation of QoS. Besides, we present a server-oriented scheme for load distribution based on the sender-initiated and receiver-initiated strategies previously used in general distributedsystems.
Nowadays, the prevalence of multimedia applications mandates that wireless networks provide higher throughput and increased spatial efficiency. Aimed primarily at achieving this goal, the first ieee 802.11n draft was ...
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ISBN:
(纸本)1595935193
Nowadays, the prevalence of multimedia applications mandates that wireless networks provide higher throughput and increased spatial efficiency. Aimed primarily at achieving this goal, the first ieee 802.11n draft was recently approved. In the draft, MIMO and frame aggregation are utilized to improve the PHY and MAC layers in single-hop WLANs by achieving high raw rates and goodput. However, in the context of multi-hop wireless ad hoc networks, the hidden terminal, exposed terminal, and deafness problems remain unsolved by ieee 802.11n. Consequently, this greatly degrades the MAC efficiency in multi-hop wireless ad hoc networks, even in the presence of frame aggregation. In this paper, we propose a novel MAC scheme that utilizes MIMO distributed spatial multiplexing to solve all the aforementioned problems, resulting in high throughput and fairness in multi-hop wireless ad hoc networks. Moreover, our scheme can be integrated with frame aggregation to further enhance the network performance. Copyright 2006 ACM.
Failing down is going to be a crucial problem to an elder today. In many countries, unintentional injury was being one of the leading causes of death in persons over age 65 years. As the society now, there are more an...
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ISBN:
(纸本)9728865597
Failing down is going to be a crucial problem to an elder today. In many countries, unintentional injury was being one of the leading causes of death in persons over age 65 years. As the society now, there are more and more solitary elders of life alone and because of the isolation, it is necessary to design an intelligent and sensitive falling detector for the elderly people. In this paper, we present an intelligent and portable fall detection device based on artificial neural network technology. This fall detector consists of two main components: accelerometer and microprocessor. The tri-axis accelerometer is used to continuously measure the variation of elder's 3 ways acceleration. The microprocessor reads the signals from the accelerometer and performs the fall activity recognition through a back-propagation neural network model. This device is integrated in a small box which can be holding on the belt for elder.
There is ongoing research and development in the field of hybrid position and force control of the assembly robots at the Department of Automation and Applied Informatics and the Department of Control Engineering and ...
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ISBN:
(纸本)9728865600
There is ongoing research and development in the field of hybrid position and force control of the assembly robots at the Department of Automation and Applied Informatics and the Department of Control Engineering and Information Technology, Budapest University of Technology and Economics. As result, an Experimental Robot Controller was built for the special needs of the project. Both the hardware and the software system of the controller are under continuous development. The most recent achievement is, a built in six-component force-torque sensor. The development of the software system is currently dealing with the extension of the programming environment with force-torque control possibilities. There are numerous industrial applications for force and torque control (i.e. screw driver, welder), but a flexible equipment can provide much more than just the possibility of solving a single task. This paper presents an overview of the robot controller hardware, separately detailing the force-torque sensor interface. The second part of this paper overviews the software system of the controller and the possibilities of its extensions for force control tasks.
Reputation systems for e-commerce uses past behaviors as a predictor of future behaviors. Reputation systems must meet the challenge on how to differentiate honest feedbacks from dishonest ones in order to reduce the ...
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Reputation systems for e-commerce uses past behaviors as a predictor of future behaviors. Reputation systems must meet the challenge on how to differentiate honest feedbacks from dishonest ones in order to reduce the system vulnerability due to malicious attacks. To address this issue, we propose a distributed reputation and trust management broker framework, called DIRECT, for dishonesty prevention. In DIRECT, malicious attacks are monitored and detected by local and cross-broker check mechanisms using statistical distribution test technologies. In the presence of dishonest feedbacks, DIRECT effectively classifies users into the green (good) and red (bad) groups. It saves the correct reputation information provided by the green group, and reduces the impact of dishonest feedbacks from the red group. The performance study shows that the DIRECT sanity check mechanism works effectively in the presence of dishonest and malicious feedbacks
The success and widespread use of Web service technology is bound to the availability of tools for rapidly discovering services and for composing their operations. We present a system for service discovery and composi...
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The success and widespread use of Web service technology is bound to the availability of tools for rapidly discovering services and for composing their operations. We present a system for service discovery and composition based on syntactic and semantic matching of the published service interfaces. The system relies on accurate preprocessing of the available services, that is, on the indexing time of the services' descriptions. The composition task is performed by index lookup and an efficient heuristic for graph traversing. The presented system is the VitaLab entry for the syntactic and semantic WS-challenge 2006
Tracking mobile targets is an important application of wireless sensor networks. However, mobility of the target brings new challenges to designing energy-efficient and scalable data collection schemes. A novel dynami...
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Tracking mobile targets is an important application of wireless sensor networks. However, mobility of the target brings new challenges to designing energy-efficient and scalable data collection schemes. A novel dynamic grid-based tracking (DGT) scheme for tracking mobile target is proposed in this paper. This scheme is distributed in nature, and can be adaptive to the mobility of the target. The underlying idea of embedding a virtual grid structure and restricting mobility-related choices to grid nodes can be generally applied to other wireless sensor networks applications, where mobility is an important consideration during protocol design
The P2P service-oriented environment presents new opportunities and challenges for distributedcomputing and resource sharing. In this paper, we present a middleware infrastructure, called CCSD, for decentralized serv...
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The P2P service-oriented environment presents new opportunities and challenges for distributedcomputing and resource sharing. In this paper, we present a middleware infrastructure, called CCSD, for decentralized service discovery in a wide-area ad hoc P2P service-oriented environment. Two of the key ideas of a CCSD P2P network are: 1) the concept of context awareness is extended to the awareness of service capacities of P2P peers, by which peers are able to understand and compare each other's service capacities; and 2) a peer's capacity context description is replicated in several designated peers in addition to the peer itself. Using a hash table, the description of the most suitable capacity context for a service request can be located quickly and the service request is forwarded to and served at the peer associated with that capacity context. CCSD, designed to satisfy the dynamic and constrained nature of the ad hoc P2P environments, benefits service users in the environments by providing the most suitable service capacity transparently
Our paper presents an agent-based simulation environment for task scheduling in distributed computer systems (grid). The scheduler enables the simultaneous allocation of bundles comprising resources such as CPU time, ...
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Our paper presents an agent-based simulation environment for task scheduling in distributed computer systems (grid). The scheduler enables the simultaneous allocation of bundles comprising resources such as CPU time, communication bandwidth, volatile, and non-volatile memory. The resources are allocated by an iterative combinatorial auction with proxy-bidding agents trying to acquire their desired resource allocation profiles. In order to support an efficient bidding process, the auctioneer provides resource price information to the bidding agents. Due to the complementarities and substitutionalities of the bid bundles in the proposed setting, the calculation of these prices is computationally expensive. This article proposes two different price approximation mechanisms: one scarcity based-scheme and a second approach using shadow prices based on the dual formulation of the relaxed linear program of the allocation problem. The stability of both allocation mechanisms is compared in the context of a closed grid system (economy) where agents buy and sell production capacity. The objective of each agent is to acquire complementary resource capacity to increase his productivity. The system's pricing and the agents' bidding behavior is evaluated based on both measures in situations of gradually increasing resource failure to test the stability of the allocation mechanism
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