Journal of Computer and System Sciences最新文献

{"title":"Blackout-tolerant temporal spanners","authors":"Davide Bilò ,&nbsp;Gianlorenzo D'Angelo ,&nbsp;Luciano Gualà ,&nbsp;Stefano Leucci ,&nbsp;Mirko Rossi","doi":"10.1016/j.jcss.2023.103495","DOIUrl":"10.1016/j.jcss.2023.103495","url":null,"abstract":"<div><p>We introduce the notions of <em>blackout-tolerant</em> temporal <em>α</em>-spanner of a temporal graph <em>G</em> which is a subgraph of <em>G</em> that preserves the distances between pairs of vertices of interest in <em>G</em> up to a multiplicative factor of <em>α</em>, even when the graph edges at a single time-instant become unavailable. In particular, we consider the <em>single-source</em>, <em>single-pair</em>, and <em>all-pairs</em> cases and, for each case we look at three quality requirements: <em>exact</em> distances (i.e., <span><math><mi>α</mi><mo>=</mo><mn>1</mn></math></span>), <em>almost-exact</em> distances (i.e., <span><math><mi>α</mi><mo>=</mo><mn>1</mn><mo>+</mo><mi>ε</mi></math></span> for an arbitrarily small constant <span><math><mi>ε</mi><mo>&gt;</mo><mn>0</mn></math></span>), and <em>connectivity</em> (i.e., unbounded <em>α</em>). We provide almost tight bounds on the <em>size</em> of such spanners for <em>general</em> temporal graphs and for <em>temporal cliques</em>, showing that they are either very sparse (i.e., they have <span><math><mover><mrow><mi>O</mi></mrow><mrow><mo>˜</mo></mrow></mover><mo>(</mo><mi>n</mi><mo>)</mo></math></span> edges) or they must have size <span><math><mi>Ω</mi><mo>(</mo><msup><mrow><mi>n</mi></mrow><mrow><mn>2</mn></mrow></msup><mo>)</mo></math></span> in the worst case, where <em>n</em> is the number of vertices of <em>G</em>. We also investigate multiple blackouts and <em>k-edge fault-tolerant temporal spanners</em>.</p></div>","PeriodicalId":50224,"journal":{"name":"Journal of Computer and System Sciences","volume":"141 ","pages":"Article 103495"},"PeriodicalIF":1.1,"publicationDate":"2023-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0022000023001009/pdfft?md5=35a28914507288d7957b1fcfa27d6087&pid=1-s2.0-S0022000023001009-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138493942","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Lifting query complexity to time-space complexity for two-way finite automata","authors":"Shenggen Zheng ,&nbsp;Yaqiao Li ,&nbsp;Minghua Pan ,&nbsp;Jozef Gruska ,&nbsp;Lvzhou Li","doi":"10.1016/j.jcss.2023.103494","DOIUrl":"10.1016/j.jcss.2023.103494","url":null,"abstract":"<div><p><span><span>Time-space tradeoff has been studied in a variety of models, such as Turing machines, branching programs, and </span>finite automata, etc. While communication complexity as a technique has been applied to study finite automata, it seems it has not been used to study time-space tradeoffs of finite automata. We design a new technique showing that separations of query complexity can be lifted, via communication complexity, to separations of time-space complexity of two-way finite automata. As an application, one of our main results exhibits the first example of a language </span><em>L</em> such that the time-space complexity of two-way probabilistic finite automata with a bounded error (2PFA) is <span><math><mover><mrow><mi>Ω</mi></mrow><mrow><mo>˜</mo></mrow></mover><mo>(</mo><msup><mrow><mi>n</mi></mrow><mrow><mn>2</mn></mrow></msup><mo>)</mo></math></span>, while of exact two-way quantum finite automata with classical states (2QCFA) is <span><math><mover><mrow><mi>O</mi></mrow><mrow><mo>˜</mo></mrow></mover><mo>(</mo><msup><mrow><mi>n</mi></mrow><mrow><mn>5</mn><mo>/</mo><mn>3</mn></mrow></msup><mo>)</mo></math></span><span>, that is, we demonstrate for the first time that exact quantum computing has an advantage in time-space complexity comparing to classical computing.</span></p></div>","PeriodicalId":50224,"journal":{"name":"Journal of Computer and System Sciences","volume":"141 ","pages":"Article 103494"},"PeriodicalIF":1.1,"publicationDate":"2023-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138493943","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Corrigendum to “Prediction, learning, uniform convergence, and scale-sensitive dimensions” [J. Comput. Syst. Sci. 56 (2) (1998) 174–190]","authors":"Peter L. Bartlett ,&nbsp;Philip M. Long","doi":"10.1016/j.jcss.2023.103465","DOIUrl":"https://doi.org/10.1016/j.jcss.2023.103465","url":null,"abstract":"","PeriodicalId":50224,"journal":{"name":"Journal of Computer and System Sciences","volume":"140 ","pages":"Article 103465"},"PeriodicalIF":1.1,"publicationDate":"2023-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0022000023000703/pdfft?md5=5fea357eab14a31f7d2bb2a0d38598ad&pid=1-s2.0-S0022000023000703-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"92122518","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Solving problems on generalized convex graphs via mim-width","authors":"Flavia Bonomo-Braberman ,&nbsp;Nick Brettell ,&nbsp;Andrea Munaro ,&nbsp;Daniël Paulusma","doi":"10.1016/j.jcss.2023.103493","DOIUrl":"https://doi.org/10.1016/j.jcss.2023.103493","url":null,"abstract":"<div><p>A bipartite graph <span><math><mi>G</mi><mo>=</mo><mo>(</mo><mi>A</mi><mo>,</mo><mi>B</mi><mo>,</mo><mi>E</mi><mo>)</mo></math></span> is <span><math><mi>H</mi></math></span>-convex for some family of graphs <span><math><mi>H</mi></math></span> if there exists a graph <span><math><mi>H</mi><mo>∈</mo><mi>H</mi></math></span> with <span><math><mi>V</mi><mo>(</mo><mi>H</mi><mo>)</mo><mo>=</mo><mi>A</mi></math></span> such that the neighbours in <em>A</em> of each <span><math><mi>b</mi><mo>∈</mo><mi>B</mi></math></span> induce a connected subgraph of <em>H</em>. Many <span><math><mi>NP</mi></math></span>-complete problems are polynomial-time solvable for <span><math><mi>H</mi></math></span>-convex graphs when <span><math><mi>H</mi></math></span> is the set of paths. The underlying reason is that the class has bounded mim-width. We extend this result to families of <span><math><mi>H</mi></math></span>-convex graphs where <span><math><mi>H</mi></math></span> is the set of cycles, or <span><math><mi>H</mi></math></span> is the set of trees with bounded maximum degree and a bounded number of vertices of degree at least 3. As a consequence, we strengthen many known results via one general and short proof. We also show that the mim-width of <span><math><mi>H</mi></math></span>-convex graphs is unbounded if <span><math><mi>H</mi></math></span> is the set of trees with arbitrarily large maximum degree or an arbitrarily large number of vertices of degree at least 3.</p></div>","PeriodicalId":50224,"journal":{"name":"Journal of Computer and System Sciences","volume":"140 ","pages":"Article 103493"},"PeriodicalIF":1.1,"publicationDate":"2023-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0022000023000983/pdfft?md5=fde8f2dacccba7a95013faa87b835770&pid=1-s2.0-S0022000023000983-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134656790","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Bounded incentives in manipulating the probabilistic serial rule","authors":"Haoqiang Huang ,&nbsp;Zihe Wang ,&nbsp;Zhide Wei ,&nbsp;Jie Zhang","doi":"10.1016/j.jcss.2023.103491","DOIUrl":"https://doi.org/10.1016/j.jcss.2023.103491","url":null,"abstract":"<div><p>The Probabilistic Serial mechanism is valued for its fairness and efficiency in addressing the random assignment problem. However, it lacks truthfulness, meaning it works well only when agents' stated preferences match their true ones. Significant utility gains from strategic actions may lead self-interested agents to manipulate the mechanism, undermining its practical adoption. To gauge the potential for manipulation, we explore an extreme scenario where a manipulator has complete knowledge of other agents' reports and unlimited computational resources to find their best strategy. We establish tight incentive ratio bounds of the mechanism. Furthermore, we complement these worst-case guarantees by conducting experiments to assess an agent's average utility gain through manipulation. The findings reveal that the incentive for manipulation is very small. These results offer insights into the mechanism's resilience against strategic manipulation, moving beyond the recognition of its lack of incentive compatibility.</p></div>","PeriodicalId":50224,"journal":{"name":"Journal of Computer and System Sciences","volume":"140 ","pages":"Article 103491"},"PeriodicalIF":1.1,"publicationDate":"2023-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134656791","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Performance modeling and analysis for randomly walking mobile users with Markov chains","authors":"Keqin Li","doi":"10.1016/j.jcss.2023.103492","DOIUrl":"https://doi.org/10.1016/j.jcss.2023.103492","url":null,"abstract":"<div><p>We treat user equipments (UEs) and mobile edge clouds (MECs) as M/G/1 queueing systems, which are the most suitable, powerful, and manageable models. We propose a computation offloading strategy which can satisfy all UEs served by an MEC and develop an efficient method to find such a strategy. We use discrete-time Markov chains, continuous-time Markov chains, and semi-Markov processes to characterize the mobility of UEs, and calculate the joint probability distribution of the locations of UEs at any time. We extend our Markov chains to incorporate mobility cost into consideration, and are able to obtain the average response time of a UE with location change penalty. We can algorithmically predict the overall average response time of tasks generated on a UE and also demonstrate numerical data and examples. We consider the power constrained MEC speed setting problem and develop an algorithm to solve the problem for two power consumption models.</p></div>","PeriodicalId":50224,"journal":{"name":"Journal of Computer and System Sciences","volume":"140 ","pages":"Article 103492"},"PeriodicalIF":1.1,"publicationDate":"2023-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91987534","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Orienting undirected phylogenetic networks","authors":"Katharina T. Huber ,&nbsp;Leo van Iersel ,&nbsp;Remie Janssen ,&nbsp;Mark Jones ,&nbsp;Vincent Moulton ,&nbsp;Yukihiro Murakami ,&nbsp;Charles Semple","doi":"10.1016/j.jcss.2023.103480","DOIUrl":"https://doi.org/10.1016/j.jcss.2023.103480","url":null,"abstract":"<div><p>This paper studies the relationship between undirected (unrooted) and directed (rooted) phylogenetic networks. We describe a polynomial-time algorithm for deciding whether an undirected nonbinary phylogenetic network, given the locations of the root and reticulation vertices, can be oriented as a directed nonbinary phylogenetic network. Moreover, we characterize when this is possible and show that, in such instances, the resulting directed nonbinary phylogenetic network is unique. In addition, without being given the location of the root and the reticulation vertices, we describe an algorithm for deciding whether an undirected binary phylogenetic network <em>N</em> can be oriented as a directed binary phylogenetic network of a certain class. The algorithm is fixed-parameter tractable (FPT) when the parameter is the level of <em>N</em> and is applicable to classes of directed phylogenetic networks that satisfy certain conditions. As an example, we show that the well-studied class of binary tree-child networks satisfies these conditions.</p></div>","PeriodicalId":50224,"journal":{"name":"Journal of Computer and System Sciences","volume":"140 ","pages":"Article 103480"},"PeriodicalIF":1.1,"publicationDate":"2023-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49738295","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fast and succinct population protocols for Presburger arithmetic","authors":"Philipp Czerner,&nbsp;Roland Guttenberg,&nbsp;Martin Helfrich,&nbsp;Javier Esparza","doi":"10.1016/j.jcss.2023.103481","DOIUrl":"https://doi.org/10.1016/j.jcss.2023.103481","url":null,"abstract":"<div><p><span>In their 2006 seminal paper in Distributed Computing, Angluin et al. present a construction that, given any Presburger predicate, outputs a leaderless population protocol that decides the predicate. The protocol for a predicate of size </span><em>m</em> runs in <span><math><mi>O</mi><mo>(</mo><mi>m</mi><mo>⋅</mo><msup><mrow><mi>n</mi></mrow><mrow><mn>2</mn></mrow></msup><mi>log</mi><mo>⁡</mo><mi>n</mi><mo>)</mo></math></span> expected number of interactions, which is almost optimal in <em>n</em>, the number of interacting agents. However, the number of states is exponential in <em>m</em>. Blondin et al. presented at STACS 2020 another construction that produces protocols with a polynomial number of states, but exponential expected number of interactions. We present a construction that produces protocols with <span><math><mi>O</mi><mo>(</mo><mi>m</mi><mo>)</mo></math></span> states that run in expected <span><math><mi>O</mi><mo>(</mo><msup><mrow><mi>m</mi></mrow><mrow><mn>7</mn></mrow></msup><mo>⋅</mo><msup><mrow><mi>n</mi></mrow><mrow><mn>2</mn></mrow></msup><mo>)</mo></math></span> interactions, optimal in <em>n</em>, for all inputs of size <span><math><mi>Ω</mi><mo>(</mo><mi>m</mi><mo>)</mo></math></span>. For this, we introduce population computers, a generalization of population protocols, and show that our computers for Presburger predicates can be translated into fast and succinct population protocols.</p></div>","PeriodicalId":50224,"journal":{"name":"Journal of Computer and System Sciences","volume":"140 ","pages":"Article 103481"},"PeriodicalIF":1.1,"publicationDate":"2023-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"92122519","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A near-linear kernel for bounded-state parsimony distance","authors":"Elise Deen ,&nbsp;Leo van Iersel ,&nbsp;Remie Janssen ,&nbsp;Mark Jones ,&nbsp;Yukihiro Murakami ,&nbsp;Norbert Zeh","doi":"10.1016/j.jcss.2023.103477","DOIUrl":"https://doi.org/10.1016/j.jcss.2023.103477","url":null,"abstract":"<div><p>The maximum parsimony distance <span><math><msub><mrow><mi>d</mi></mrow><mrow><mtext>MP</mtext></mrow></msub><mo>(</mo><msub><mrow><mi>T</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>,</mo><msub><mrow><mi>T</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>)</mo></math></span> and the bounded-state maximum parsimony distance <span><math><msubsup><mrow><mi>d</mi></mrow><mrow><mtext>MP</mtext></mrow><mrow><mi>t</mi></mrow></msubsup><mo>(</mo><msub><mrow><mi>T</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>,</mo><msub><mrow><mi>T</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>)</mo></math></span> measure the difference between two phylogenetic trees <span><math><msub><mrow><mi>T</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>,</mo><msub><mrow><mi>T</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> in terms of the maximum difference between their parsimony scores for any character (with <em>t</em> a bound on the number of states in the character, in the case of <span><math><msubsup><mrow><mi>d</mi></mrow><mrow><mtext>MP</mtext></mrow><mrow><mi>t</mi></mrow></msubsup><mo>(</mo><msub><mrow><mi>T</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>,</mo><msub><mrow><mi>T</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>)</mo></math></span>). While computing <span><math><msub><mrow><mi>d</mi></mrow><mrow><mtext>MP</mtext></mrow></msub><mo>(</mo><msub><mrow><mi>T</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>,</mo><msub><mrow><mi>T</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>)</mo></math></span> was previously shown to be fixed-parameter tractable with a linear kernel, no such result was known for <span><math><msubsup><mrow><mi>d</mi></mrow><mrow><mtext>MP</mtext></mrow><mrow><mi>t</mi></mrow></msubsup><mo>(</mo><msub><mrow><mi>T</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>,</mo><msub><mrow><mi>T</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>)</mo></math></span>. In this paper, we prove that computing <span><math><msubsup><mrow><mi>d</mi></mrow><mrow><mtext>MP</mtext></mrow><mrow><mi>t</mi></mrow></msubsup><mo>(</mo><msub><mrow><mi>T</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>,</mo><msub><mrow><mi>T</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>)</mo></math></span> is fixed-parameter tractable for all <em>t</em>. Specifically, we prove that this problem has a kernel of size <span><math><mi>O</mi><mo>(</mo><mi>k</mi><mi>lg</mi><mo>⁡</mo><mi>k</mi><mo>)</mo></math></span>, where <span><math><mi>k</mi><mo>=</mo><msubsup><mrow><mi>d</mi></mrow><mrow><mtext>MP</mtext></mrow><mrow><mi>t</mi></mrow></msubsup><mo>(</mo><msub><mrow><mi>T</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>,</mo><msub><mrow><mi>T</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>)</mo></math></span>. As the primary analysis tool, we introduce the concept of leg-disjoint incompatible quartets, which may be of independent interest.</p></div>","PeriodicalId":50224,"journal":{"name":"Journal of Computer and System Sciences","volume":"140 ","pages":"Article 103477"},"PeriodicalIF":1.1,"publicationDate":"2023-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49726020","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The satisfiability problem for a quantitative fragment of PCTL","authors":"Miroslav Chodil,&nbsp;Antonín Kučera","doi":"10.1016/j.jcss.2023.103478","DOIUrl":"https://doi.org/10.1016/j.jcss.2023.103478","url":null,"abstract":"<div><p>We propose a generic method for proving the decidability of the finite satisfiability problem for PCTL fragments and demonstrate its applicability in several non-trivial examples.</p></div>","PeriodicalId":50224,"journal":{"name":"Journal of Computer and System Sciences","volume":"139 ","pages":"Article 103478"},"PeriodicalIF":1.1,"publicationDate":"2023-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49725834","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}