Proceedings of the 2019 ACM Symposium on Principles of Distributed Computing最新文献

{"title":"Efficient Multiparty Interactive Coding for Insertions, Deletions, and Substitutions","authors":"R. Gelles, Y. Kalai, Govind Ramnarayan","doi":"10.1145/3293611.3331621","DOIUrl":"https://doi.org/10.1145/3293611.3331621","url":null,"abstract":"In the field of interactive coding, two or more parties wish to carry out a distributed computation over a communication network that may be noisy. The ultimate goal is to develop efficient coding schemes that can tolerate a high level of noise while increasing the communication by only a constant factor (i.e., constant rate). In this work we consider synchronous communication networks over an arbitrary topology, in the powerful adversarial insertion-deletion noise model. Namely, the noisy channel may adversarially alter the content of any transmitted symbol, as well as completely remove a transmitted symbol or inject a new symbol into the channel. We provide efficient, constant rate schemes that successfully conduct any computation with high probability as long as the adversary corrupts at most ε over m fraction of the total communication, where m is the number of links in the network and ε is a small constant. This scheme assumes an oblivious adversary which is independent of the parties' inputs and randomness. We can remove this assumption and resist a worst-case adversary at the price of being resilient to ε over m log m errors. While previous work considered the insertion-deletion noise model in the two-party setting, to the best of our knowledge, our scheme is the first multiparty scheme that is resilient to insertions and deletions. Furthermore, our scheme is the first computationally efficient scheme in the multiparty setting that is resilient to adversarial noise.","PeriodicalId":153766,"journal":{"name":"Proceedings of the 2019 ACM Symposium on Principles of Distributed Computing","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123272369","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Logarithmic Expected-Time Leader Election in Population Protocol Model","authors":"Y. Sudo, Fukuhito Ooshita, Taisuke Izumi, H. Kakugawa, T. Masuzawa","doi":"10.1145/3293611.3331585","DOIUrl":"https://doi.org/10.1145/3293611.3331585","url":null,"abstract":"In this paper, we present a leader election protocol in the population protocol model that stabilizes within O(log n) parallel time in expectation with O(log n) states per agent, where n is the number of agents. Given a rough knowledge m of the population size n such that m ≥ = log2 n and m=O(log n), this protocol guarantees that exactly one leader is elected and the unique leader is kept forever thereafter.","PeriodicalId":153766,"journal":{"name":"Proceedings of the 2019 ACM Symposium on Principles of Distributed Computing","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128361940","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Trivial Yet Optimal Solution to Vertex Fault Tolerant Spanners","authors":"Gregory Bodwin, Shyamal Patel","doi":"10.1145/3293611.3331588","DOIUrl":"https://doi.org/10.1145/3293611.3331588","url":null,"abstract":"We give a short and easy upper bound on the worst-case size of fault tolerant spanners, which improves on all prior work and is fully optimal at least in the setting of vertex faults.","PeriodicalId":153766,"journal":{"name":"Proceedings of the 2019 ACM Symposium on Principles of Distributed Computing","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116300766","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Weighted Matchings via Unweighted Augmentations","authors":"Buddhima Gamlath, S. Kale, Slobodan Mitrovic, O. Svensson","doi":"10.1145/3293611.3331603","DOIUrl":"https://doi.org/10.1145/3293611.3331603","url":null,"abstract":"We design a generic method to reduce the task of finding weighted matchings to that of finding short augmenting paths in unweighted graphs. This method enables us to provide efficient implementations for approximating weighted matchings in the massively parallel computation (MPC) model and in the streaming model. For the MPC and the multi-pass streaming model, we show that any algorithm computing a (1-δ)-approximate unweighted matching in bipartite graphs can be translated into an algorithm that computes a (1-(ε(δ))-approximate maximum weighted matching. Furthermore, this translation incurs only a constant factor (that depends on ε > 0) overhead in the complexity. Instantiating this with the current best MPC algorithm for unweighted matching yields a (1 - ε)-approximation algorithm for maximum weighted matching that uses Oε(log log n) rounds, O(m/n) machines per round, and O(npoly(logn)) memory per machine. This improves upon the previous best approximation guarantee of (1/2-ε) for weighted graphs. In the context of single-pass streaming with random edge arrivals, our techniques yield a (1/2+c)-approximation algorithm thus breaking the natural barrier of 1/2.","PeriodicalId":153766,"journal":{"name":"Proceedings of the 2019 ACM Symposium on Principles of Distributed Computing","volume":"132 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130895420","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hardness of Minimal Symmetry Breaking in Distributed Computing","authors":"A. Balliu, J. Hirvonen, D. Olivetti, J. Suomela","doi":"10.1145/3293611.3331605","DOIUrl":"https://doi.org/10.1145/3293611.3331605","url":null,"abstract":"A graph is weakly 2-colored if the nodes are labeled with colors black and white such that each black node is adjacent to at least one white node and vice versa. In this work we study the distributed computational complexity of weak 2-coloring in the standard łocal model of distributed computing, and how it is related to the distributed computational complexity of other graph problems. First, we show that weak 2-coloring is a minimal distributed symmetry-breaking problem for regular even-degree trees and high-girth graphs: if there is any non-trivial locally checkable labeling problem that is solvable in o(log⋅ n) rounds with a distributed graph algorithm in the middle of a regular even-degree tree, then weak 2-coloring is also solvable in o(log⋅ n) rounds there. Second, we prove a tight lower bound of Ω(log ⋅ n) for the distributed computational complexity of weak 2-coloring in regular trees; previously only a lower bound of Ω n(log log⋅ n) was known. By minimality, the same lower bound holds for any non-trivial locally checkable problem inside regular even-degree trees.","PeriodicalId":153766,"journal":{"name":"Proceedings of the 2019 ACM Symposium on Principles of Distributed Computing","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130902087","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Complexity of (Δ+1) Coloring in Congested Clique, Massively Parallel Computation, and Centralized Local Computation","authors":"Yi-Jun Chang, Manuela Fischer, M. Ghaffari, Jara Uitto, Yufan Zheng","doi":"10.1145/3293611.3331607","DOIUrl":"https://doi.org/10.1145/3293611.3331607","url":null,"abstract":"In this paper, we present new randomized algorithms that improve the complexity of the classic (Δ+1)-coloring problem, and its generalization (Δ+1)-list-coloring, in three well-studied models of distributed, parallel, and centralized computation: Distributed Congested Clique: We present an O(1)-round randomized algorithm for (Δ + 1)-list-coloring in the congested clique model of distributed computing. This settles the asymptotic complexity of this problem. It moreover improves upon the O(log* Δ)-round randomized algorithms of Parter and Su [DISC'18] and O((log log Δ)⋅ log* Δ)-round randomized algorithm of Parter [ICALP'18]. Massively Parallel Computation: We present a randomized (Δ + 1)-list-coloring algorithm with round complexity O(√ log log n ) in the Massively Parallel Computation (MPC) model with strongly sublinear memory per machine. This algorithm uses a memory of O(nα) per machine, for any desirable constant α > 0, and a total memory of Õ (m), where m is the number of edges in the graph. Notably, this is the first coloring algorithm with sublogarithmic round complexity, in the sublinear memory regime of MPC. For the quasilinear memory regime of MPC, an O(1)-round algorithm was given very recently by Assadi et al. [SODA'19]. Centralized Local Computation: We show that (Δ + 1)-list-coloring can be solved by a randomized algorithm with query complexity Δ O(1) … O(log n), in the centralized local computation model. The previous state of the art for (Δ+1)-list-coloring in the centralized local computation model are based on simulation of known LOCAL algorithms. The deterministic O(√ Δ poly log Δ + log* n)-round LOCAL algorithm of Fraigniaud et al. [FOCS'16] can be implemented in the centralized local computation model with query complexity ΔO(√ Δ poly log Δ) … O(log* n); the randomized O(log* Δ) + 2^O(√ log log n)-round LOCAL algorithm of Chang et al. [STOC'18] can be implemented in the centralized local computation model with query complexity ΔO(log* Δ) … O(log n).","PeriodicalId":153766,"journal":{"name":"Proceedings of the 2019 ACM Symposium on Principles of Distributed Computing","volume":"76 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134222706","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Distributed Complexity of Locally Checkable Problems on Paths is Decidable","authors":"A. Balliu, S. Brandt, Yi-Jun Chang, D. Olivetti, M. Rabie, J. Suomela","doi":"10.1145/3293611.3331606","DOIUrl":"https://doi.org/10.1145/3293611.3331606","url":null,"abstract":"Consider a computer network that consists of a path with n nodes. The nodes are labeled with inputs from a constant-sized set, and the task is to find output labels from a constant-sized set subject to some local constraints---more formally, we have an LCL (locally checkable labeling) problem. How many communication rounds are needed (in the standard LOCAL model of computing) to solve this problem? It is well known that the answer is always either O(1) rounds, or Θ(log⋅ n) rounds, or Θ(n) rounds. In this work we show that this question is decidable (albeit PSPACE-hard): we present an algorithm that, given any LCL problem defined on a path, outputs the distributed computational complexity of this problem and the corresponding asymptotically optimal algorithm.","PeriodicalId":153766,"journal":{"name":"Proceedings of the 2019 ACM Symposium on Principles of Distributed Computing","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132421101","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optimal Memory-Anonymous Symmetric Deadlock-Free Mutual Exclusion","authors":"Zahra Aghazadeh, Damien Imbs, M. Raynal, G. Taubenfeld, Philipp Woelfel","doi":"10.1145/3293611.3331594","DOIUrl":"https://doi.org/10.1145/3293611.3331594","url":null,"abstract":"The notion of an anonymous shared memory, introduced by Taubenfeld in PODC 2017, considers that processes use different names for the same memory location. As an example, a location name A used by a process p and a location name B ≠ A used by another process q can correspond to the very same memory location X, and similarly for the names B used by p and A used by q which may (or may not) correspond to the same memory location Y ≠ X. In this context, the PODC paper presented a 2-process symmetric deadlock-free mutual exclusion (mutex) algorithm and a necessary condition on the size m of the anonymous memory for the existence of such an n-process algorithm. This condition states that m must be belongs to M(n) {1} where M(n)= {m: ∀ ℓ: (1) < ℓ ≤ n: gcd(ℓ,m)=1). Symmetric means here that,process identities define a specific data type which allows a process to check only if two identities are equal or not. The present paper presents two optimal deadlock-free symmetric mutual exclusion algorithms for n-process systems where communication is through m registers. The first algorithm, which considers anonymous read/write registers, works for any m which is ≥ n and belongs to the set M(n). It follows that this condition on m is both necessary and sufficient for symmetric deadlock-free mutual exclusion in this anonymity context, and this algorithm is optimal with respect to m The second algorithm, which considers anonymous read/modify/write atomic registers, works for any m∈ M(n), which is shown to be necessary and sufficient for anonymous read/modify/write registers. It follows that, when m > 1, m ∈ M(n) is a tight characterization of the size of the anonymous shared memory needed to solve deadlock-free mutex, be the registers read/write or read/modify/write.","PeriodicalId":153766,"journal":{"name":"Proceedings of the 2019 ACM Symposium on Principles of Distributed Computing","volume":"77 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132059568","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Efficient Size Estimation and Impossibility of Termination in Uniform Dense Population Protocols","authors":"David Doty, Mahsa Eftekhari","doi":"10.1145/3293611.3331627","DOIUrl":"https://doi.org/10.1145/3293611.3331627","url":null,"abstract":"We study uniform population protocols: networks of anonymous agents whose pairwise interactions are chosen at random, where each agent uses an identical transition algorithm that does not depend on the population size n. Many existing polylog(n) time protocols for leader election and majority computation are nonuniform: to operate correctly, they require all agents to be initialized with an approximate estimate of n (specifically, the value łfloorłog nrfloor). Our first main result is a uniform protocol for calculating łog(n) pm O(1) with high probability in O(łog^2 n) time and O(łog^4 n) states (O(łog łog n) bits of memory). The protocol is not terminating : it does not signal when the estimate is close to the true value of łog n. If it could be made terminating with high probability, this would allow composition with protocols requiring a size estimate initially. We do show how our main protocol can be indirectly composed with others in a simple and elegant way, based on leaderless phase clocks, demonstrating that those protocols can in fact be made uniform. However, our second main result implies that the protocol cannot be made terminating, a consequence of a much stronger result: a uniform protocol for any task requiring more than constant time cannot be terminating even with probability bounded above 0, if infinitely many initial configurations are dense : any state present initially occupies Ømega(n) agents. (In particular no leader is allowed.) Crucially, the result holds no matter the memory or time permitted.","PeriodicalId":153766,"journal":{"name":"Proceedings of the 2019 ACM Symposium on Principles of Distributed Computing","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115825736","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Implementing Mediators with Asynchronous Cheap Talk","authors":"Ittai Abraham, D. Dolev, I. Geffner, Joseph Y. Halpern","doi":"10.1145/3293611.3331623","DOIUrl":"https://doi.org/10.1145/3293611.3331623","url":null,"abstract":"A mediator can help non-cooperative agents obtain an equilibrium that may otherwise not be possible. We study the ability of players to obtain the same equilibrium without a mediator, using only cheap talk, that is, nonbinding pre-play communication. Previous work has considered this problem in a synchronous setting. Here we consider the effect of asynchrony on the problem, and provide upper bounds for implementing mediators. Considering asynchronous environments introduces new subtleties, including exactly what solution concept is most appropriate and determining what move is played if the cheap talk goes on forever. Different results are obtained depending on whether the move after such \"infinite play'' is under the control of the players or part of the description of the game.","PeriodicalId":153766,"journal":{"name":"Proceedings of the 2019 ACM Symposium on Principles of Distributed Computing","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128645617","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}