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27th IEEE Computer Security Foundations Symposium (CSF)

作者： Culnane, Chris Schneider, Steve Univ Surrey Dept Comp Guildford GU2 5XH Surrey England

ISBN: (纸本)9781479942909

The Secure Web Bulletin Board (WBB) is a key component of verifiable election systems. However, there is very little in the literature on their specification, design and implementation, and there are no formally analysed designs. The WBB is used in the context of election verification to publish evidence of voting and tallying that voters and officials can check, and where challenges can be launched in the event of malfeasance. In practice, the election authority has responsibility for implementing the web bulletin board correctly and reliably, and will wish to ensure that it behaves correctly even in the presence of failures and attacks. To ensure robustness, an implementation will typically use a number of peers to be able to provide a correct service even when some peers go down or behave dishonestly. In this paper we propose a new protocol to implement such a Web Bulletin Board, motivated by the needs of the vVote verifiable voting system. Using a distributed algorithm increases the complexity of the protocol and requires careful reasoning in order to establish correctness. Here we use the Event-B modelling and refinement approach to establish correctness of the peered design against an idealised specification of the bulletin board behaviour. In particular we have shown that for n peers, a threshold of t > 2n/3 peers behaving correctly is sufficient to ensure correct behaviour of the bulletin board distributed design. The algorithm also behaves correctly even if honest or dishonest peers temporarily drop out of the protocol and then return. The verification approach also establishes that the protocols used within the bulletin board do not interfere with each other. This is the first time a peered secure web bulletin board suite of protocols has been formally verified.

关键词： cryptographic protocols distributed algorithms electronic mail Event-B modelling bulletin board behaviour specification bulletin board distributed design dishonest peers distributed algorithm election authority election verification honest peers peered bulletin board refinement approach secure WBB secure Web bulletin board vVote verifiable voting system verifiable election systems vote tallying voting evidence Context Cryptography Databases Nominations and elections Protocols Publishing Robustness Event-B Formal Modelling Secure Web Bulletin Board Verifiable Voting Protocols Verification Bulletin boards distributed algorithms cryptographic protocols protocols electronic mail cryptography Publishing Verification Peers Robustness Database vote system

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Accurate and Efficient Counting in Dynamic Networks 33

Accurate and Efficient Counting in Dynamic Networks

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IEEE 33rd International Symposium on Reliable distributed Systems

作者： Yang, Zhiwei Wu, Weigang Chen, Yishun Lin, Xiaola Sun Yat Sen Univ Dept Comp Sci Guangzhou 510006 Guangdong Peoples R China Zhongkai Univ Agr & Engn Coll Computat Sci Guangzhou 510006 Guangdong Peoples R China SYSU CMU Shunde Int Joint Res Inst Shunde Peoples R China

ISBN: (纸本)9781479955848

Dynamic network is the abstraction of networks with frequent topology changes arising from node mobility or other reasons. With the model of dynamic network, fundamental distributed computing problems can be formally studied with rigorous correctness. In this work, we study the counting problem, which plays a significant role in many applications, such as all-to-all information dissemination. Existing counting algorithms for dynamic networks are mostly estimation based and randomized, and cannot achieve accurate results deterministically. To address this problem, we adopt the diffusing computation approach in this paper. Although this approach has been widely used to solve different distributed computing problems, due to dynamic topology changes, existing diffusing computation algorithms cannot work under dynamic network models. To address such challenge, we firstly define a new dynamicity model, named (Q, S)-distance, which is used to describe dynamic changes of information propagation time. Based on (Q, S)-distance, we design two different counting algorithms. The first algorithm focuses on extending typical diffusing computation approach by handling topology changes. Different from existing algorithms, which have two phases, our algorithms contain three phases and the new phase is used to determine and notify the termination of tree growing, which the major challenge is caused by topology dynamicity. The second algorithm further extends the first one by incorporating a cluster-based hierarchy to reduce communication cost. The correctness of both the algorithms is formally proved and their performances in time cost and communication cost are analyzed.

关键词： counting dynamic network diffusing computation distributed algorithm cluster

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Mutual Exclusion algorithms in the Shared Queue Model

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15th International Conference on distributed Computing and Networking (ICDCN)

作者： Wang, Junxing Wang, Zhengyu Tsinghua Univ ITCS Inst Interdisciplinary Informat Sci Beijing 100084 Peoples R China

ISBN: (纸本)9783642452482;9783642452499

Resource sharing for asynchronous processors with mutual exclusion property is a fundamental task in distributed computing. We investigate the problem in a natural setting: for the communications between processors, they only share several queues supporting enqueue and dequeue operations. It is well-known that there is a very simple algorithm using only one queue when the queue also supports the peek operation, but it is still open whether we could implement mutual exclusion distributed system without the peek operation. In this paper, we propose two mutual exclusion starvation-free algorithms for this more restricted setting. The first algorithm is a protocol for arbitrary number of processors which share 2 queues;the second one is a protocol for 2 processors sharing only one queue.

关键词： Mutual Exclusion Starvation Free Queue distributed algorithm

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FlashTrack: A Fast, In-network Tracking System for Sensor Networks

FlashTrack: A Fast, In-network Tracking System for Sensor Ne...

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9th IEEE International Conference on distributed Computing in Sensor Systems (DCOSS)

作者： Jiang, Hao Zhai, Jiannan Hallstrom, Jason O. Clemson Univ Sch Comp Clemson SC 29631 USA

ISBN: (纸本)9781479946181

We revisit the classic object tracking problem with a novel and effective, yet straightforward distributed solution for resource-lean devices. The difficulty of object tracking lies in the mismatch between the limited computational capacity of typical sensor nodes and the processing requirements of typical tracking algorithms. In this paper, we introduce an in-network system for tracking mobile objects using resource-lean sensors. The system is based on a distributed, dynamically-scoped tracking algorithm which alters the event detection region and reporting rate based on object speed. A leader node records the detected samples across the event region and estimates the object's location in situ. We study the performance of our tracking implementation on an 80-node testbed. The results show that it achieves high performance, even for very fast objects, and is readily implemented on resource-lean sensors. While the area is well-studied, the unique combination of algorithmic features represents a significant addition to the literature.

关键词： distributed algorithm Network Protocol Object Tracking Wireless Sensor Networks Network protocols distributed algorithms tracking objects Wireless sensor networks TRACKING SYSTEM Sensor networks tracking Sensors

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Access-efficient QoS-aware data replication to maximize user satisfaction in cloud computing environments 15

Access-efficient QoS-aware data replication to maximize user...

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15th International Conference on Parallel and distributed Computing, Applications and Technologies (PDCAT)

作者： Shorfuzzaman, Mohammad Taif Univ Dept Comp Sci At Taif Saudi Arabia

ISBN: (纸本)9781479983346

Cloud computing infrastructures capable of providing scalable storage and computing resources can efficiently be used for big data storage and processing. There are growing trends in developing data-intensive (big data) applications in this computing environment that need to access massive datasets. Hence, effective data management such as data availability and efficient accesses has become critical requirements in these applications. This can be achieved by using data replication, which offers reduced data access latency, higher data availability and improved system load balancing. Moreover, different applications may have different quality-of-service (QoS) requirements. To continuously support the QoS requirement of an application, we propose a highly distributed QoS-aware replication technique that computes the optimal data center locations for the replicas so that the overall replication cost is minimized. Further, the replication strategy aims at maximizing QoS satisfaction to improve data availability and reduce access latency. The problem is formulated using dynamic programming. Finally, simulation experiments are performed using widely observed data access patterns to demonstrate the effectiveness of the proposed technique.

关键词： Cloud computing data replication availability access latency dynamic programming QoS requirement distributed algorithm

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Belief Propagation for Spatial Spectrum Access Games 14

Belief Propagation for Spatial Spectrum Access Games

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15th ACM International Symposium on Mobile Ad Hoc Networking and Computing

作者： Wang, Yi-Kai Yin, Yitong Zhong, Sheng Nanjing Univ State Key Lab Novel Software Technol Nanjing 210046 Peoples R China

ISBN: (纸本)9781450326209

Consider a wireless network in which selfish users compete with each other for usage of spectrum. We view this competition as a spatial spectrum access game. There are two fundamental questions regarding this game: how to converge to the optimal Nash equilibrium, and how to converge fast. To answer these two questions, we apply a technique called Belief Propagation to design algorithms for users in this game, which can guarantee fast convergence to an optimal or nearly optimal pure strategy Nash equilibrium. Specifically, when the interference graph is an undirected tree or a directed acyclic graph, our algorithms can find the optimal Nash equilibrium in linear time. For general undirected interference graph, our algorithm converges fast as long as the game is potential (which is the case for many typical scenarios). For some other typical spatial spectrum access games, our algorithms can provide a good approximation to the optimal Nash equilibrium.

关键词： Wireless Network distributed algorithm Game Theory Belief Propagation

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A Parallel algorithm for the Best k-mismatches Alignment Problem

A Parallel Algorithm for the Best <i>k</i>-mismatches Alignm...

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22nd Euromicro International Conference on Parallel, distributed, and Network-Based Processing (PDP)

作者： Del Fabbro, Cristian Tardivo, Fabio Policriti, Alberto Inst Appl Genom Udine Italy Univ Udine I-33100 Udine Italy

ISBN: (纸本)9781479927289

We propose a parallel algorithm that solves the best k-mismatches alignment problem against a genomic reference using the "one sequence/multiple processes" paradigm and distributed memory. Our proposal is designed to take advantage of a computing cluster using MPI (Message Passing Interface) for communication. Our solution distributes the reference among different nodes and each sequence is processed concurrently by different nodes. When a (putative) best solution is found, the successful process propagates the information to other nodes, reducing search space and saving computation time. The distributed algorithm was developed in C++ and optimized for the PLX and FERMI supercomputers, but it is compatible with every OpenMPI-based cluster. It was included in the ERNE (Extended Randomized Numerical alignEr) package, whose aim is to provide an all-inclusive set of tools for short reads alignment and cleaning. ERNE is free software, distributed under the Open Source License (GPL V3) and can be downloaded at: http://***. The algorithm described in this work is implemented in the ERNE-PMAP and ERNE-PBS5 programs, the former designed to align DNA and RNA sequences, while the latter is optimized for bisulphite-treated sequences.

关键词： C++ language DNA RNA application program interfaces bioinformatics distributed memory systems message passing parallel algorithms public domain software software packages C++ programming DNA sequence alignment ERNE-PBS5 programs ERNE-PMAP programs Extended Randomized Numerical aligner package FERMI supercomputers GPL V3 MPI OpenMPI-based cluster PLX supercomputers RNA sequence alignment best k-mismatches alignment problem bisulphite-treated sequences computation time computing cluster distributed algorithm distributed memory free software message passing interface one sequence-multiple processes paradigm open source license parallel algorithm search space reduction Bioinformatics Clustering algorithms DNA Genomics Next generation networking Sequential analysis Software bs-seq erne mpi parallel sequence alignment

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What Do We Need to Know to Elect in Networks with Unknown Participants? 1

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21st International Colloquium on Structural Information and Communication Complexity (SIROCCO)

作者： Chalopin, Jeremie Godard, Emmanuel Naudin, Antoine Univ Aix Marseille LIF Marseille France

ISBN: (数字)9783319096209

ISBN: (纸本)9783319096209;9783319096193

A network with unknown participants is a communication network where the processes have very partial knowledge of the system. Nodes do not know the full set of participating nodes and some nodes do not even know the full set of nodes they can communicate directly with. It is a "contact list" like network where the initial communication is possibly asymmetric and one can communicate with an unknown neighbour only if one has been first contacted by this neighbour. This model is quite natural and of important theoretical interest. It has also proved useful for the study of bootstrapping mobile ad hoc networks. In this paper, we investigate the classical Leader Election problem in general networks with unknown participants. We give the first necessary and sufficient condition on global knowledge that nodes should be provided in order to solve Election problem. Since Election problem is a useful benchmark in distributed computability investigations, this result could lead to a complete characterisation of what is solvable in networks with unknown participants.

关键词： distributed algorithm Message Passing Leader Election distributed Computability Unknown Participants Structural Knowledge

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distributed algorithm for Dynamic Logical Topology Reconfiguration in IP over WDM Networks

Distributed Algorithm for Dynamic Logical Topology Reconfigu...

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IEEE Symposium on Computers and Communications (ISCC 2009)

作者： Tran, Phuong Nga Killat, Ulrich Tech Univ Hamburg Commun Networks Dept Hamburg Germany

ISBN: (纸本)9781424446728

In this paper, we present a novel distributed algorithm to solve the logical topology reconfiguration problem for IP over WDM networks under dynamic traffic. From the optimization model proposed in ill, we apply the Lagrangian relaxation to eliminate the capacity constraint and form a dual problem whose optimal solution is the lower bound of the original one. The dual problem is then decomposed into sub-problems, which can be solved in a distributed manner. Based on the solution of the dual problem, a heuristic algorithm is proposed to obtain a good feasible solution for the orginal reconfiguration problem. Our distributed algorithm fulfils all requirements of the reconfiguration process, such as no service disruption, load balancing in the new logical topology while allowing to add and to delete multiple lightpaths. Moreover, the distributed approach offers a high scalability. Not limited to small or medium-sized networks as the centralized model in Ill, this distributed algorithm can be applied to large networks with the computation time increasing linearly with the network size. The performance of the proposed distributed algorithm, which lends itself to a protocol implementation, is investigated and compared with the corresponding centralized approach.

关键词： IP over WDM lightpaths logical topology distributed algorithm reconfiguration integer linear programming (ILP) Lagrangian relaxation traffic engineering

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distributed Identification of the Most Critical Node for Average Consensus

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IFAC Proceedings Volumes 2014年第3期47卷 1843-1848页

作者： Hao Liu Xianghui Cao Jianping He Peng Cheng Jiming Chen Youxian Sun State Key Lab. of Industrial Control Technology Zhejiang University Hangzhou 310027 China

In present computer networks, cyber attacks, such as compromising and energy depleting attacks, can cause malfunction or even failure of nodes, and can be significantly harmful to the convergence property of the average consensus algorithms. In this paper, we aim to distributively find the most critical nodes in the sense that removing it causes the largest destruction to the converging speed of an average consensus algorithm among all the nodes. The algebraic connectivity is used to assess the destruction and thus the importance of a node. We design two methods to estimate the algebraic connectivity and analyze their bounds for the estimation error. Based on this, we propose a fully distributed algorithm for the nodes to iteratively find the most critical one. Simulation results demonstrate the effectiveness of our algorithm.

关键词： critical nodes algebraic connectivity Fiedler vector distributed algorithm

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