Dynamic configuration techniques such as DVFS (Dynamic Voltage and Frequency Scaling) and turning on/off computers are well known ways to promote energy consumption reduction in web server clusters. this paper demonst...
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this paper describes a new fault-tolerant routing algorithm for the k-ary n-cube using the concept of "probability vectors". To compute these vectors, a node determines first its faulty set, which contains a...
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ISBN:
(纸本)9781581134452
this paper describes a new fault-tolerant routing algorithm for the k-ary n-cube using the concept of "probability vectors". To compute these vectors, a node determines first its faulty set, which contains all its neighbouring nodes that are faulty or unreachable due to faulty nodes or links. Each node then calculates a probability vector, where the i-th element represents the probability that a destination node at distance i cannot be reached using a minimal path due to a faulty node or link. the probability vectors are used by all the nodes to achieve an efficient fault-tolerant routing in the network. Results from a performance analysis presented below show that the new algorithm exhibits good fault-tolerance properties in terms of the achieved percentage of reachability and routing distances.
Opportunistic grids are a class of computational grids that can leverage the idle processing and storage capacity of shared workstations in laboratories, companies, and universities to perform useful computation. OppS...
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ISBN:
(纸本)9781605581668
Opportunistic grids are a class of computational grids that can leverage the idle processing and storage capacity of shared workstations in laboratories, companies, and universities to perform useful computation. OppStore is a middleware that allows using the free disk space of machines from an opportunistic grid for the distributed storage of application data. But when machines depart from the grid, it is necessary to reconstruct the fragments that were stored in that machines. Depending on the amount of stored data and the rate of machine departures, the generated traffic may make the distributed storage of data infeasible. In this work we present and evaluate a fragment recovery mechanism that makes viable to achieve redundancy and large data scale in a dynamic environment. Copyright 2009 acm.
A mobile replicated database is comprised of several mobile and fixed servers and clients interconnected through a wireless network. In order to ensure data consistency in mobile replicated databases, several replicat...
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Meta-communication can be defined as all exchanges of information that are related to the conceptual model of the system, including the communication that takes place in order to clarify or overcome problems during th...
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the proceedings contain 407 papers. the topics discussed include: network protocol interoperability testing based on contextual signatures and passive testing;practical distributed voter-verifiable secret ballot syste...
ISBN:
(纸本)9781605581668
the proceedings contain 407 papers. the topics discussed include: network protocol interoperability testing based on contextual signatures and passive testing;practical distributed voter-verifiable secret ballot system;using geo-spatial session tagging for smart multicast session discovery;a holistic mechanism against file pollution in peer-to-peer networks;robust scheduler for grid networks;NECTAR: a DTN routing protocol based on neighborhood contact history;DoSTRACK: a system for defending against DoS attacks;secure routing in peer-to-peer distributed hash tables;BPR: a bit-level packet recovery in wireless sensor networks;multi-step attack modeling and simulation (MsAMS) framework based on mobile ambients;quality of service management in GMPLS-based grid OBS networks;new content-aware request distribution policies in web clusters providing multiple services;securing key issuing in peer-to-peer networks;preservation of ordering in a network of brokers;and developing and evaluating web multimodal interfaces a case study with usability principles.
For distributed software systems, ensuring their availability under intentional attacks is critical. Traffic analysis, conducted by the attacker, could reveal the protocol being carried out by the components. Furtherm...
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Mobile systems characterize by dynamic environments, thus requiring adaptive and context aware mechanisms to perceive changes in the execution context and to dynamically adapt to them. We propose a framework for devel...
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ISBN:
(纸本)9781605581668
Mobile systems characterize by dynamic environments, thus requiring adaptive and context aware mechanisms to perceive changes in the execution context and to dynamically adapt to them. We propose a framework for developing adaptive context aware applications which employs aspect-oriented techniques and dynamic composition to modularize the adaptive behavior and to keep apart the application logic from this behavior. Copyright 2009 acm.
When running workflows in the cloud it is appealing to use spot instances that can be acquired at a fraction of the cost of on-demand instances. Unfortunately, spot instances can be revoked at any time, creating uncer...
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ISBN:
(纸本)9781450359337
When running workflows in the cloud it is appealing to use spot instances that can be acquired at a fraction of the cost of on-demand instances. Unfortunately, spot instances can be revoked at any time, creating uncertainty about task completion times, which is an impairment for workflows with timeliness requirements. While workflow scheduling has been subject to extensive research, the problem of optimally scheduling deadline-constraint workflows in the cloud while dealing withthe uncertainty caused by spot instance revocations has not been fully addressed. In this paper, we plan the execution of workflows in cloud environments to minimize the monetary cost while being subject to timeliness constraints. Our approach constructs a Markov Decision Process (MDP) of the workflow execution and looks up for the optimal policy taking into account the user preferences in time and cost. the optimal solution is generated offline and actions selected on-the-fly, depending on the occurrence of failures due to instance revocations. Experimental results with a real-world scientific workflow application demonstrate that, in comparison to approaches that rely on simple heuristics to schedule tasks, our planning-based approach is able to generate reliable solutions that are cheaper and able to meet deadlines.
Population protocols are a model of computation in which an arbitrary number of indistinguishable finite-state agents interact in pairs. the goal of the agents is to decide by stable consensus whether their initial gl...
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ISBN:
(纸本)9781450385480
Population protocols are a model of computation in which an arbitrary number of indistinguishable finite-state agents interact in pairs. the goal of the agents is to decide by stable consensus whether their initial global configuration satisfies a given property, specified as a predicate on the set of configurations. the state complexity of a predicate is the number of states of a smallest protocol that computes it. Previous work by Blondin et al. has shown that the counting predicates x >= eta have state complexity O(log eta) for leaderless protocols and O(log log eta) for protocols with leaders. We obtain the first non-trivial lower bounds: the state complexity of x >= eta is Omega(log log log eta) for leaderless protocols, and the inverse of a non-elementary function for protocols with leaders.
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