BitTorrent ensures cooperation among peers through its inbuilt collaborative mechanisms, however due to lack of proper incentives, significant amount of free riding is observed in it. Though in the existing literature...
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ISBN:
(纸本)9783642113215
BitTorrent ensures cooperation among peers through its inbuilt collaborative mechanisms, however due to lack of proper incentives, significant amount of free riding is observed in it. Though in the existing literature, there exists some strategies to prevent free-riding, however, in case of large swarm sizes, it can be shown that they fail to stop free riding attempts effectively. To overcome this limitation, this paper presents a novel approach based on propagating the knowledge about the existence of possible free riders in the form of reputation among the peers within the swarm. It is shown, how a possible free riding attempt on a peer is reported to others and how tins knowledge is utilized in deciding whether to upload to a particular peer or not within a Bit Torrent swarm. Simulation results demonstrate how the proposed strategy effectively punishes free riders even in large swarm sizes.
Cloud computing is an emerging paradigm to provide Infrastructure as a Service (IaaS). In this paper we present NEPTUNE-IaaS, a software system able to support the whole lifecycle of IaaS provisioning in a Virtual Clu...
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ISBN:
(纸本)9783642141218
Cloud computing is an emerging paradigm to provide Infrastructure as a Service (IaaS). In this paper we present NEPTUNE-IaaS, a software system able to support the whole lifecycle of IaaS provisioning in a Virtual Cluster environment. Our system allows interactive design of complex system topologies and their efficient mapping onto the available physical resources of a cluster. It also provides transparent VM migration features across geographically distributed datacenters, thanks to the adoption of the Service Switching paradigm. We also evaluate the effectiveness of the VM mapping procedures and compare our solution against other existing IaaS solutions.
A distributed algorithm is self-stabilizing if after faults and attacks hit the system and place it in some arbitrary global state, the system recovers from this catastrophic situation without external intervention in...
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ISBN:
(纸本)9783642113215
A distributed algorithm is self-stabilizing if after faults and attacks hit the system and place it in some arbitrary global state, the system recovers from this catastrophic situation without external intervention in finite time. Unidirectional networks preclude many common techniques in self-stabilization from being used, such as preserving local predicates. The focus of this work is on the classical vertex coloring problem, that is a basic building block for many resource allocation problems arising in wireless sensor networks. In this paper, we investigate the gain in complexity that can be obtained through randomization. We present a probabilistically self-stabilizing algorithm that uses k states per process, where k is a parameter of the algorithm. When k = Delta + 1, the algorithm recovers in expected O(Delta n) actions. When k may grow arbitrarily, the algorithm recovers in expected O(n) actions in total. Thus, our algorithm can be made optimal with respect to space or time complexity. Our case study hints that randomization could help filling the complexity gap between bidirectionnal and unidirectionnal networks.
The continuously rising energy demand of data centers has already reached the two-digit megawatt area by now. The rising energy costs force operators to search for effective methods for energy reduction. A popular, so...
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Enterprise distributed real-time and embedded (DRE) publish/subscribe (pub/sub) systems manage resources and data that are vital to users. Cloud computing-where computing resources are provisioned elastically and leas...
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ISBN:
(纸本)9783642169540
Enterprise distributed real-time and embedded (DRE) publish/subscribe (pub/sub) systems manage resources and data that are vital to users. Cloud computing-where computing resources are provisioned elastically and leased as a service-is an increasingly popular deployment paradigm. Enterprise DRE pub/sub systems can leverage cloud computing provisioning services to execute needed functionality when on-site computing resources are not available. Although cloud computing provides flexible on-demand computing and networking resources, enterprise DRE pub/sub systems often cannot accurately characterize their behavior a priori for the variety of resource configurations cloud computing supplies (e.g., CPU and network bandwidth), which makes it hard for DRE systems to leverage conventional cloud computing platforms. This paper provides two contributions to the study of how autonomic configuration of DRE pub/sub middleware can provision and use on-demand cloud resources effectively. We first describe how supervised machine learning can configure DRE pub/sub middleware services and transport protocols autonomically to support end-to-end quality-of-service (QoS) requirements based on cloud computing resources. We then present results that empirically validate how computing and networking resources affect enterprise DRE pub/sub system QoS. These results show how supervised machine learning can configure DRE pub/sub middleware adaptively in < 10 mu sec with bounded time complexity to support key QoS reliability and latency requirements.
In this paper, we present an approach to construct a built-in block-based hierarchical index structures, like Rtree, to organize data sets in one, two, or higher dimensional space and improve the query performance tow...
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With the growth of Massively Multiuser Virtual Environments (MMVEs) and increasingly interactive social networking platforms, it is widely accepted that their convergence renders today's centralized hosting approa...
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A wireless mesh network (WMN) is a self-configured and self-organized wireless network in which nodes maintain the mesh connectivity among themselves. However, in WMN, current multicast algorithms are merely deployed ...
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ISBN:
(纸本)9780889868205
A wireless mesh network (WMN) is a self-configured and self-organized wireless network in which nodes maintain the mesh connectivity among themselves. However, in WMN, current multicast algorithms are merely deployed within an intra-domain multicasting. In this paper, a novel protocol is proposed to support the inter-domain multicasting with handover. The protocol introduces the Mesh Rendezvous Point (MRP) and Mesh Entry Point (MEP) that establish an IP tunnel between each other for transmitting multicast packets towards/outwards the intradomain. The protocol is evaluated on the sceanarios without a handover situation. The validation and performance of the proposed protocol is evaluated using OMNeT++ simulator.
Networked Cyber-Physical Systems (NCPS) present many challenges that are not suitably addressed by existing distributedcomputing paradigms. They twist be reactive and maintain an overall situation awareness that emer...
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ISBN:
(纸本)9783642163548
Networked Cyber-Physical Systems (NCPS) present many challenges that are not suitably addressed by existing distributedcomputing paradigms. They twist be reactive and maintain an overall situation awareness that emerges from partial distributed knowledge. They must achieve system goals through local, asynchronous actions, using (distributed) control loops through which the environment provides essential feedback. Typical NCPS are open, dynamic, and heterogeneous in many dimensions, and often need to be rapidly instantiated and deployed for a given mission. To address these challenges, we pursue a declarative approach to provide an abstraction from the high complexity of NCPS and avoid error-prone and time-consuming low-level programming. A longer-term goal is to develop a distributed computational and logical foundation that supports a wide spectrum of system operation between autonomy and cooperation to adapt to resource constraints, in particular to limitations of computational, energy, and networking resources. Here, we present first steps toward a logical framework for NCPS that combines distributed reasoning and asynchronous control in space and time. The logical framework is based on partially ordered knowledge sharing, a distributedcomputing paradigm for loosely coupled systems that does not require continuous network connectivity. We illustrate our approach with a simulation prototype of our logical framework in the context of networked mobile robot;teams that operate in an abstract instrumented cyber-physical space with sensors.
Accurate prediction of energy consumption early in the design process is essential to efficiently optimize algorithms and protocols. However, despite energy efficiency gathering significant attention in networking res...
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