Consensus is one of the most fundamental distributedcomputing problems. In particular, it serves as a building block in many replication based fault-tolerant systems and in particular in multiple recent blockchain so...
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ISBN:
(纸本)9781450377515
Consensus is one of the most fundamental distributedcomputing problems. In particular, it serves as a building block in many replication based fault-tolerant systems and in particular in multiple recent blockchain solutions. Depending on its exact variant and other environmental assumptions, solving consensus requires multiple communication rounds. Yet, there are known optimistic protocols that guarantee termination in a single communication round under favorable conditions. In this paper we present a generic optimizer that can turn any consensus protocol into an optimized protocol that terminates in a single communication round whenever all nodes start with the same predetermined value and no Byzantine failures occur (although node crashes are allowed). This is regardless of the network timing assumptions and additional oracle capabilities assumed by the base consensus protocol being optimized. In the case of benign failures, our optimizer works whenever the number of faulty nodes f < n/2. For Byzantine behavior, our optimizer's resiliency depends on the validity variant sought. In the case of classical validity, it can accommodate f < n/4 Byzantine failures. With the more recent external validity function assumption, it works whenever f < n/3. Either way, our optimizer only relies on oral messages, thereby imposing very light-weight crypto requirements.
In this paper, we present GRAPHTM, an efficient and scalable framework for processing transactions in a distributed environment. The distributed environment is modeled as a graph where each node of the graph is a proc...
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ISBN:
(纸本)9781450377515
In this paper, we present GRAPHTM, an efficient and scalable framework for processing transactions in a distributed environment. The distributed environment is modeled as a graph where each node of the graph is a processing node that issues transactions. The objects that transactions use to execute are also on the graph nodes (the initial placement may be arbitrary). The transactions execute on the nodes which issue them after collecting all the objects that they need following the data-flow model of computation. This collection is done by issuing the requests for the objects as soon as transaction starts and wait until all required objects for the transaction come to the requesting node. The challenge is on how to schedule the transactions so that two crucial performance metrics, namely (i) total execution time to commit all the transactions, and (ii) total communication cost involved in moving the objects to the requesting nodes, are minimized. We implemented GRAPHTM in Java and assessed its performance through 3 micro-benchmarks and 5 complex benchmarks from STAMP benchmark suite on 5 different network topologies, namely, clique, line, grid, cluster, and star, that make an underlying communication network for a representative set of distributed systems commonly used in practice. The results show the efficiency and scalability of our approach.
The MCS lock was the first mutual exclusion lock to support an arbitrary number of processes with unknown identities such that each process can acquire and release the lock in a constant number of RMRs on both Cache-C...
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ISBN:
(纸本)9781450377515
The MCS lock was the first mutual exclusion lock to support an arbitrary number of processes with unknown identities such that each process can acquire and release the lock in a constant number of RMRs on both Cache-Coherent and distributed Shared Memory multiprocessors. The MCS algorithm, however, has a shortcoming: its Exit section is not bounded. The algorithm also requires hardware support for more than one special instruction, namely, Fetch&Store and Compare&Swap. Many MCS-style algorithms were subsequently designed to overcome these shortcomings, but to the best of our knowledge they either lack some desirable property of the MCS lock or introduce a new shortcoming. In this paper we present a new MCS-style algorithm that has all of the desirable properties and no ostensible shortcoming. We also provide a rigorous, invariant-based proof of correctness. To realize a bounded Exit section, all prior MCS-style algorithms use either the "node-switching" or the "node-toggling" strategy. Our work unifies these two strategies: we present a single algorithm which, when appropriately instantiated, yields both a node-switching and a node-toggling algorithm. Moreover, the two algorithms so derived are the simplest in their respective classes among all known MCS-style algorithms.
The proceedings contain 6 papers. The topics discussed include: computational strategies to increase ef?ciency of Gaussian-process-driven autonomous experiments;scientific image restoration anywhere;distributed global...
ISBN:
(纸本)9781728159836
The proceedings contain 6 papers. The topics discussed include: computational strategies to increase ef?ciency of Gaussian-process-driven autonomous experiments;scientific image restoration anywhere;distributed global digital volume correlation by optimal transport;sparse data management in HDF5;Balsam: near real-time experimental data analysis on supercomputers;and data processing at the linac coherent light source.
The purpose of this study is to analyze the influence of word of mouth effect on Koreans' overseas travel destination decisions. The tourist group was divided into package travelers and free travelers, and various...
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The purpose of this study is to analyze the influence of word of mouth effect on Koreans' overseas travel destination decisions. The tourist group was divided into package travelers and free travelers, and various influencing factors were included as independent variables. As a result of the analysis, we found that package travelers tend to supply information to social media after travel, while free travelers collect information from social media before travel and use it for decision-making. Economic variables, which have been claimed as a major factor in previous studies, have relatively low influence, and in particular, economic indicators of Korea are not significant.
Anchor Link Prediction (ALP) across social networks plays a pivotal role in inter-network applications. The difficulty of anchor link prediction across social networks lies in how to consider the factors affecting nod...
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Anchor Link Prediction (ALP) across social networks plays a pivotal role in inter-network applications. The difficulty of anchor link prediction across social networks lies in how to consider the factors affecting nodes alignment comprehensively. In recent years, predicting anchor links based on network embedding has become the main trend. For social networks, previous anchor link prediction methods first integrate neighbourhood nodes associated with a user node to obtain a fusion embedding vector from global perspective, and then predict anchor links based on the similarity between fusion vectors corresponding with different user nodes. However, the social network structure contains a lot of structural noise, which is ignored by the fusion vector. To address the challenge, we propose a novel structure-noise-aware anchor link prediction framework across social networks (SNALP), which models all the edges of the node from a fine-grained perspective and evaluates the contribution of them. Then, each edge is given a different weight according to their contribution. While the trusted edges are enhanced, the effects of noisy edges are reduced. SNALP can solve the network embedding and structure-noise-aware alignment under a unified optimization framework. Extensive experiments on real social network datasets demonstrate the effectiveness and efficiency of the proposed approach compared with several state-of-the-art methods.
The communication distributed radio concept distributes the RADIO frequency transceiver (TX/RX) sensor portion and most of the processing portion of the system to the aircraft area near the antenna. The rest of the di...
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ISBN:
(纸本)9781665400718
The communication distributed radio concept distributes the RADIO frequency transceiver (TX/RX) sensor portion and most of the processing portion of the system to the aircraft area near the antenna. The rest of the digital portion of the system can be hosted on a common computing platform, such as the Integrated Modular Avionics System (IMA).
Bilateral friend queries have attracted increasing interest in social networks, as each user has a common requirement to specify a policy for the other. However, existing bilateral friend query schemes either only can...
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Bilateral friend queries have attracted increasing interest in social networks, as each user has a common requirement to specify a policy for the other. However, existing bilateral friend query schemes either only cannot support conjunctive policy matching, where the match is successful if the policy is a subset of attributes, or compromise user privacy, which reduces users' enthusiasm for friend query services. In this paper, we propose a secure bilateral friend query with conjunctive policy matching named BFQ. Specifically, the matchmaking encryption technique is utilized to achieve bilateral policy specification, where both sender and requester can specify policies for the other. Then, based on the Newton interpolation theorem, we design a novel conjunctive policy matching algorithm, where the match succeeds if and only if user authenticity holds and the policies of both parties are the subset of attributes. Otherwise, nothing is revealed except whether the match occurs or not. Security analysis proves that user authenticity and privacy, i.e., attribute privacy, policy privacy, and match privacy, are well guaranteed under the chosen-plaintext attack. We then implement a real prototype application and demonstrate that BFQ has practical efficiency through theoretical and experimental evaluation.
The advancements in computer and networking technologies created closely connected cyberspaces. Nevertheless, this also invalidated many traditional and isolated/local network solutions and introduced higher cybersecu...
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ISBN:
(数字)9781665476799
ISBN:
(纸本)9781665476805
The advancements in computer and networking technologies created closely connected cyberspaces. Nevertheless, this also invalidated many traditional and isolated/local network solutions and introduced higher cybersecurity risk. As a solution, NIST's Zero-Trust Architecture (ZTA) with “never trust, always verify” principle has been widely accepted; yet, its implementation, enforcement, and compliance-check mechanisms are still immature as the solutions are generally applied manually. In this paper, we present an autonomic computing based management engine for networking of a cyberspace, we refer as Autonomic ZTA-based Network Management Engine (AZNME), which monitors an asset's network connections, checks if these connections fulfill ZTA requirements, and evaluates trust continuously, and takes mitigation actions as needed. As a proof of concept, we implemented the AZNME focusing on active connections (e.g., IPs and ports) to enforce policies and create firewall rules based on trust evaluation.
A sensational rise of various applications and businesses has led to the rise of data being collected, it is getting harder to store this data on a single machine. It has become more feasible to manage dispersed data ...
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ISBN:
(纸本)9781665438124
A sensational rise of various applications and businesses has led to the rise of data being collected, it is getting harder to store this data on a single machine. It has become more feasible to manage dispersed data sets and organizations. That is the reason distributed data mining methods have become popular. Perhaps the main hurdle of data mining is to perform data clustering. While many clustering calculations exist for certain and uncertain data sets, there is need of productive calculations for distributed data sets. In this paper, a modified hierarchical clustering algorithm is proposed for uncertain dataset to improve timing in execution of the process.
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