We present a model for distributed network formation with cost expressing robustness in an adversary model. There are n players, each representing a vertex. Players may establish links to other players, building a link incurs a cost α. Individual cost comprises this building cost plus an indirect cost. After the network is built, an adversary deletes one link. The adversary is modeled by a random experiment, specified by a probability distribution on the links. Players know this distribution. Indirect cost for player v is the expected number of players to which v will become disconnected when the adversary strikes. We can prove an O(1) bound on the price of anarchy for two different adversaries under unilateral link formation. Under bilateral link formation, we can prove an O(1+√n/α) bound for one adversary, and for the other an asymptotically tight Ω(n) bound if α = Θ(1).
{"title":"Brief announcement: the price of anarchy for distributed network formation in an adversary model","authors":"Lasse Kliemann","doi":"10.1145/1835698.1835749","DOIUrl":"https://doi.org/10.1145/1835698.1835749","url":null,"abstract":"We present a model for distributed network formation with cost expressing robustness in an adversary model. There are n players, each representing a vertex. Players may establish links to other players, building a link incurs a cost α. Individual cost comprises this building cost plus an indirect cost. After the network is built, an adversary deletes one link. The adversary is modeled by a random experiment, specified by a probability distribution on the links. Players know this distribution. Indirect cost for player v is the expected number of players to which v will become disconnected when the adversary strikes. We can prove an O(1) bound on the price of anarchy for two different adversaries under unilateral link formation. Under bilateral link formation, we can prove an O(1+√n/α) bound for one adversary, and for the other an asymptotically tight Ω(n) bound if α = Θ(1).","PeriodicalId":447863,"journal":{"name":"Proceedings of the 29th ACM SIGACT-SIGOPS symposium on Principles of distributed computing","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128488361","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":"Session details: Regular papers","authors":"F. Petit","doi":"10.1145/3258218","DOIUrl":"https://doi.org/10.1145/3258218","url":null,"abstract":"","PeriodicalId":447863,"journal":{"name":"Proceedings of the 29th ACM SIGACT-SIGOPS symposium on Principles of distributed computing","volume":"145 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122413743","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}
We present and analyze simple distributed contention resolution protocols for wireless networks. In our setting, one is given n pairs of senders and receivers located in a metric space. Each sender wants to transmit a signal to its receiver at a prespecified power level, e.g., all senders use the same, uniform power level as it is typically implemented in practice. Our analysis is based on the physical model in which the success of a transmission depends on the Signal-to-Interference-plus-Noise-Ratio (SINR). The objective is to minimize the number of time slots until all signals are successfully transmitted. Our main technical contribution is the introduction of a measure called maximum average affectance enabling us to analyze random contention-resolution algorithms in which each packet is transmitted in each step with a fixed probability depending on the maximum average affectance. We prove that the schedule generated this way is only an O(log2 n) factor longer than the optimal one, provided that the prespecified power levels satisfy natural monontonicity properties. By modifying the algorithm, senders need not to know the maximum average affectance in advance but only static information about the network. In addition, we extend our approach to multi-hop communication achieving the same appoximation factor.
{"title":"Brief announcement: distributed contention resolution in wireless networks","authors":"Thomas Kesselheim, Berthold Vöcking","doi":"10.1145/1835698.1835731","DOIUrl":"https://doi.org/10.1145/1835698.1835731","url":null,"abstract":"We present and analyze simple distributed contention resolution protocols for wireless networks. In our setting, one is given n pairs of senders and receivers located in a metric space. Each sender wants to transmit a signal to its receiver at a prespecified power level, e.g., all senders use the same, uniform power level as it is typically implemented in practice. Our analysis is based on the physical model in which the success of a transmission depends on the Signal-to-Interference-plus-Noise-Ratio (SINR). The objective is to minimize the number of time slots until all signals are successfully transmitted. Our main technical contribution is the introduction of a measure called maximum average affectance enabling us to analyze random contention-resolution algorithms in which each packet is transmitted in each step with a fixed probability depending on the maximum average affectance. We prove that the schedule generated this way is only an O(log2 n) factor longer than the optimal one, provided that the prespecified power levels satisfy natural monontonicity properties. By modifying the algorithm, senders need not to know the maximum average affectance in advance but only static information about the network. In addition, we extend our approach to multi-hop communication achieving the same appoximation factor.","PeriodicalId":447863,"journal":{"name":"Proceedings of the 29th ACM SIGACT-SIGOPS symposium on Principles of distributed computing","volume":"356 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124201188","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}
This paper deals with pipelined queries over services. The execution plan of such queries defines an order in which the services are called. We present the theoretical underpinnings of a newly proposed algorithm that produces the optimal linear ordering corresponding to a query being executed in a decentralized manner, i.e., when the services communicate directly with each other. The optimality is defined in terms of query response time, which is determined by the bottleneck service in the plan. The properties discussed in this work allow a branch-and-bound approach to be very efficient.
{"title":"Brief announcement: on the quest of optimal service ordering in decentralized queries","authors":"Efthymia Tsamoura, A. Gounaris, Y. Manolopoulos","doi":"10.1145/1835698.1835763","DOIUrl":"https://doi.org/10.1145/1835698.1835763","url":null,"abstract":"This paper deals with pipelined queries over services. The execution plan of such queries defines an order in which the services are called. We present the theoretical underpinnings of a newly proposed algorithm that produces the optimal linear ordering corresponding to a query being executed in a decentralized manner, i.e., when the services communicate directly with each other. The optimality is defined in terms of query response time, which is determined by the bottleneck service in the plan. The properties discussed in this work allow a branch-and-bound approach to be very efficient.","PeriodicalId":447863,"journal":{"name":"Proceedings of the 29th ACM SIGACT-SIGOPS symposium on Principles of distributed computing","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128941251","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}
In this paper, we develop an analytical framework to explain the appearance of bimodal degree distribution in existing popular superpeer networks like Gnutella. The framework leads to several interesting and important inferences related to network topology and node/link dynamics. Beyond the simulation based study, we validate our framework through almost exact matching of the topological structure of Gnutella network constructed from real data.
{"title":"Brief announcement: superpeer formation amidst churn and rewiring","authors":"Bivas Mitra, S. Ghose, Niloy Ganguly","doi":"10.1145/1835698.1835733","DOIUrl":"https://doi.org/10.1145/1835698.1835733","url":null,"abstract":"In this paper, we develop an analytical framework to explain the appearance of bimodal degree distribution in existing popular superpeer networks like Gnutella. The framework leads to several interesting and important inferences related to network topology and node/link dynamics. Beyond the simulation based study, we validate our framework through almost exact matching of the topological structure of Gnutella network constructed from real data.","PeriodicalId":447863,"journal":{"name":"Proceedings of the 29th ACM SIGACT-SIGOPS symposium on Principles of distributed computing","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129023656","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}
F. Kuhn, N. Lynch, Calvin C. Newport, R. Oshman, A. Richa
Practitioners agree that unreliable links, which sometimes deliver messages and sometime do not, are an important characteristic of wireless networks. In contrast, most theoretical models of radio networks fix a static set of links and assume that these links are reliable. This gap between theory and practice motivates us to investigate how unreliable links affect theoretical bounds on broadcast in radio networks. To that end we consider a model that includes two types of links: reliable links, which always deliver messages, and unreliable links, which sometimes fail to deliver messages. We assume that the reliable links induce a connected graph, and that unreliable links are controlled by a worst-case adversary. In the new model we show an Ω(n log n) lower bound on deterministic broadcast in undirected graphs, even when all processes are initially awake and have collision detection, and an Ω(n) lower bound on randomized broadcast in undirected networks of constant diameter. This separates the new model from the classical, reliable model. On the positive side, we give two algorithms that tolerate unreliability: an O(n3/2 √log n)-time deterministic algorithm and a randomized algorithm which terminates in O(n log2 n) rounds with high probability.
{"title":"Broadcasting in unreliable radio networks","authors":"F. Kuhn, N. Lynch, Calvin C. Newport, R. Oshman, A. Richa","doi":"10.1145/1835698.1835779","DOIUrl":"https://doi.org/10.1145/1835698.1835779","url":null,"abstract":"Practitioners agree that unreliable links, which sometimes deliver messages and sometime do not, are an important characteristic of wireless networks. In contrast, most theoretical models of radio networks fix a static set of links and assume that these links are reliable. This gap between theory and practice motivates us to investigate how unreliable links affect theoretical bounds on broadcast in radio networks. To that end we consider a model that includes two types of links: reliable links, which always deliver messages, and unreliable links, which sometimes fail to deliver messages. We assume that the reliable links induce a connected graph, and that unreliable links are controlled by a worst-case adversary. In the new model we show an Ω(n log n) lower bound on deterministic broadcast in undirected graphs, even when all processes are initially awake and have collision detection, and an Ω(n) lower bound on randomized broadcast in undirected networks of constant diameter. This separates the new model from the classical, reliable model. On the positive side, we give two algorithms that tolerate unreliability: an O(n3/2 √log n)-time deterministic algorithm and a randomized algorithm which terminates in O(n log2 n) rounds with high probability.","PeriodicalId":447863,"journal":{"name":"Proceedings of the 29th ACM SIGACT-SIGOPS symposium on Principles of distributed computing","volume":"191 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122858829","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":"Session details: Brief announcements","authors":"C. Cachin","doi":"10.1145/3258215","DOIUrl":"https://doi.org/10.1145/3258215","url":null,"abstract":"","PeriodicalId":447863,"journal":{"name":"Proceedings of the 29th ACM SIGACT-SIGOPS symposium on Principles of distributed computing","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121429994","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}
Consider a distributed network in which events occur at arbitrary nodes and at unpredicted times. An event occurring at node u is sensed only by u which in turn may invoke a communication protocol that allows nodes to exchange messages with their neighbors. We are interested in the following threshold detection (TD) problem inherent to distributed computing: Given some threshold k, the goal of a TD protocol is to broadcast a termination signal when at least k events have occurred (throughout the network). In this paper we develop a randomized TD protocol that may fail with negligible probability but which significantly improves previous results in terms of the message complexity, namely, the total number of messages sent by all participating nodes. With the right choice of parameters our randomized protocol turns into a deterministic one that guarantees low communication burden for any node. This is a principal complexity measure in many applications of wireless networks and which, to the best of our knowledge, has not been bounded before in the context of such problems.
{"title":"Efficient threshold detection in a distributed environment: extended abstract","authors":"Y. Emek, Amos Korman","doi":"10.1145/1835698.1835742","DOIUrl":"https://doi.org/10.1145/1835698.1835742","url":null,"abstract":"Consider a distributed network in which events occur at arbitrary nodes and at unpredicted times. An event occurring at node u is sensed only by u which in turn may invoke a communication protocol that allows nodes to exchange messages with their neighbors. We are interested in the following threshold detection (TD) problem inherent to distributed computing: Given some threshold k, the goal of a TD protocol is to broadcast a termination signal when at least k events have occurred (throughout the network). In this paper we develop a randomized TD protocol that may fail with negligible probability but which significantly improves previous results in terms of the message complexity, namely, the total number of messages sent by all participating nodes. With the right choice of parameters our randomized protocol turns into a deterministic one that guarantees low communication burden for any node. This is a principal complexity measure in many applications of wireless networks and which, to the best of our knowledge, has not been bounded before in the context of such problems.","PeriodicalId":447863,"journal":{"name":"Proceedings of the 29th ACM SIGACT-SIGOPS symposium on Principles of distributed computing","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116212930","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}
We consider the rational secret sharing problem introduced by Halpern and Teague [1]. Some positive results have been derived by Kol and Naor[3] by considering that players only prefer to learn.The solution considers that players are of two types; one player is the short player and the rest of the players are long players. But their protocol is susceptible to coalitions if the short player colludes with any of the long players. We extend their protocol, and propose a completely collusion free, &3949;-Nash equilibrium protocol, when n ≥ 2m-1, where n is the number of players and m is the number of shares needed to construct the secret.
{"title":"Brief announcement: collusion free protocol for rational secret sharing","authors":"A. Shareef","doi":"10.1145/1835698.1835792","DOIUrl":"https://doi.org/10.1145/1835698.1835792","url":null,"abstract":"We consider the rational secret sharing problem introduced by Halpern and Teague [1]. Some positive results have been derived by Kol and Naor[3] by considering that players only prefer to learn.The solution considers that players are of two types; one player is the short player and the rest of the players are long players. But their protocol is susceptible to coalitions if the short player colludes with any of the long players. We extend their protocol, and propose a completely collusion free, &3949;-Nash equilibrium protocol, when n ≥ 2m-1, where n is the number of players and m is the number of shares needed to construct the secret.","PeriodicalId":447863,"journal":{"name":"Proceedings of the 29th ACM SIGACT-SIGOPS symposium on Principles of distributed computing","volume":"14 2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126118213","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":"Session details: Regular papers","authors":"Luís Rodrigues","doi":"10.1145/3258208","DOIUrl":"https://doi.org/10.1145/3258208","url":null,"abstract":"","PeriodicalId":447863,"journal":{"name":"Proceedings of the 29th ACM SIGACT-SIGOPS symposium on Principles of distributed computing","volume":"75 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124664965","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}
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