Journal of Computer and System Sciences最新文献

{"title":"Online computation with untrusted advice","authors":"Spyros Angelopoulos ,&nbsp;Christoph Dürr ,&nbsp;Shendan Jin ,&nbsp;Shahin Kamali ,&nbsp;Marc Renault","doi":"10.1016/j.jcss.2024.103545","DOIUrl":"10.1016/j.jcss.2024.103545","url":null,"abstract":"<div><p>We study a generalization of the advice complexity model of online computation in which the advice is provided by an untrusted source. Our objective is to quantify the impact of untrusted advice so as to design and analyze online algorithms that are robust if the advice is adversarial, and efficient is the advice is foolproof. We focus on four well-studied online problems, namely ski rental, online bidding, bin packing and list update. For ski rental and online bidding, we show how to obtain algorithms that are Pareto-optimal with respect to the competitive ratios achieved, whereas for bin packing and list update, we give online algorithms with worst-case tradeoffs in their competitiveness, depending on whether the advice is trusted or adversarial. More importantly, we demonstrate how to prove lower bounds, within this model, on the tradeoff between the number of advice bits and the competitiveness of any online algorithm.</p></div>","PeriodicalId":50224,"journal":{"name":"Journal of Computer and System Sciences","volume":"144 ","pages":"Article 103545"},"PeriodicalIF":1.1,"publicationDate":"2024-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140800465","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":"Decentralized deadlock-free enforcement of message orderings in message-based systems","authors":"Mahboubeh Samadi,&nbsp;Fatemeh Ghassemi,&nbsp;Ramtin Khosravi","doi":"10.1016/j.jcss.2024.103544","DOIUrl":"https://doi.org/10.1016/j.jcss.2024.103544","url":null,"abstract":"<div><p>Message-based systems usually consist of distributed components that communicate using asynchronous message passing. In such systems, particular message orderings may violate some required properties. Given an automata-based specification of unwanted message sequences, we propose a decentralized deadlock-free runtime enforcement algorithm to prevent the formation of such sequences. In our approach, components are equipped with monitors executed concurrently. A component is only blocked before sending or receiving the last message of a sequence, until its associated monitor checks that such a message does not complete an unwanted sequence. According to the specification of unwanted sequences, some blocked components may suffer from a deadlock. Our deadlock-free algorithm guarantees that monitors detect and resolve such deadlocks by improving the existing deadlock detection algorithms. We evaluate the efficiency and scalability of our approach in terms of the communication overhead, the prevention latency, and the overhead of deadlock detection through simulation.</p></div>","PeriodicalId":50224,"journal":{"name":"Journal of Computer and System Sciences","volume":"144 ","pages":"Article 103544"},"PeriodicalIF":1.1,"publicationDate":"2024-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140645928","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":"Labeled sample compression schemes for complexes of oriented matroids","authors":"Victor Chepoi ,&nbsp;Kolja Knauer ,&nbsp;Manon Philibert","doi":"10.1016/j.jcss.2024.103543","DOIUrl":"https://doi.org/10.1016/j.jcss.2024.103543","url":null,"abstract":"<div><p>We show that the topes of a complex of oriented matroids (abbreviated COM) of VC-dimension <em>d</em> admit a proper labeled sample compression scheme of size <em>d</em>. This considerably extends results of Moran and Warmuth on ample classes, of Ben-David and Litman on affine arrangements of hyperplanes, and of the authors on complexes of uniform oriented matroids, and is a step towards the sample compression conjecture – one of the oldest open problems in computational learning theory. On the one hand, our approach exploits the rich combinatorial cell structure of COMs via oriented matroid theory. On the other hand, viewing tope graphs of COMs as partial cubes creates a fruitful link to metric graph theory.</p></div>","PeriodicalId":50224,"journal":{"name":"Journal of Computer and System Sciences","volume":"144 ","pages":"Article 103543"},"PeriodicalIF":1.1,"publicationDate":"2024-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140605005","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":"On the parameterized complexity of interval scheduling with eligible machine sets","authors":"Danny Hermelin ,&nbsp;Yuval Itzhaki ,&nbsp;Hendrik Molter ,&nbsp;Dvir Shabtay","doi":"10.1016/j.jcss.2024.103533","DOIUrl":"10.1016/j.jcss.2024.103533","url":null,"abstract":"<div><p>We provide new parameterized complexity results for <span>Interval Scheduling on Eligible Machines</span>. In this problem, a set of <em>n</em> jobs is given to be processed non-preemptively on a set of <em>m</em> machines. Each job has a <em>processing time</em>, a <em>deadline</em>, a <em>weight</em>, and a set of <em>eligible machines</em> that can process it. The goal is to find a maximum weight subset of jobs that can each be processed on one of its eligible machines such that it completes exactly at its deadline. We focus on two parameters: The number <em>m</em> of machines, and the largest processing time <span><math><msub><mrow><mi>p</mi></mrow><mrow><mi>max</mi></mrow></msub></math></span>. Our main contribution is showing <span>W[1]</span>-hardness when parameterized by <em>m</em>. This answers Open Problem 8 of Mnich and van Bevern's list of 15 open problems in parameterized complexity of scheduling problems [Computers &amp; Operations Research, 2018]. Furthermore, we show <span>NP</span>-hardness even when <span><math><msub><mrow><mi>p</mi></mrow><mrow><mi>max</mi></mrow></msub><mo>=</mo><mi>O</mi><mo>(</mo><mn>1</mn><mo>)</mo></math></span> and present an <span>FPT</span>-algorithm with for the combined parameter <span><math><mi>m</mi><mo>+</mo><msub><mrow><mi>p</mi></mrow><mrow><mi>max</mi></mrow></msub></math></span>.</p></div>","PeriodicalId":50224,"journal":{"name":"Journal of Computer and System Sciences","volume":"144 ","pages":"Article 103533"},"PeriodicalIF":1.1,"publicationDate":"2024-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140402533","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":"Preprocessing to reduce the search space: Antler structures for feedback vertex set","authors":"Huib Donkers,&nbsp;Bart M.P. Jansen","doi":"10.1016/j.jcss.2024.103532","DOIUrl":"https://doi.org/10.1016/j.jcss.2024.103532","url":null,"abstract":"<div><p>The goal of this paper is to open up a new research direction aimed at understanding the power of preprocessing in speeding up algorithms that solve NP-hard problems exactly. We explore this direction for the classic <span>Feedback Vertex Set</span> problem on undirected graphs, leading to a new type of graph structure called <em>antler decomposition</em>, which identifies vertices that belong to an optimal solution. It is an analogue of the celebrated <em>crown decomposition</em> which has been used for <span>Vertex Cover</span>. We develop the graph structure theory around such decompositions and develop fixed-parameter tractable algorithms to find them, parameterized by the number of vertices for which they witness presence in an optimal solution. This reduces the search space of fixed-parameter tractable algorithms parameterized by the solution size that solve <span>Feedback Vertex Set</span>.</p></div>","PeriodicalId":50224,"journal":{"name":"Journal of Computer and System Sciences","volume":"144 ","pages":"Article 103532"},"PeriodicalIF":1.1,"publicationDate":"2024-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0022000024000278/pdfft?md5=2d8e7a91708f0a0fee2cda8d00eb9d75&pid=1-s2.0-S0022000024000278-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140543243","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":"A cop and robber game on edge-periodic temporal graphs","authors":"Thomas Erlebach ,&nbsp;Nils Morawietz ,&nbsp;Jakob T. Spooner ,&nbsp;Petra Wolf","doi":"10.1016/j.jcss.2024.103534","DOIUrl":"10.1016/j.jcss.2024.103534","url":null,"abstract":"<div><p>We introduce a cops and robbers game with one cop and one robber on a special type of time-varying graphs (TVGs), namely edge-periodic graphs. These are TVGs in which, for each edge <em>e</em>, a binary string <span><math><mi>τ</mi><mo>(</mo><mi>e</mi><mo>)</mo></math></span> is given such that the edge <em>e</em> is present in time step <em>t</em> if and only if <span><math><mi>τ</mi><mo>(</mo><mi>e</mi><mo>)</mo></math></span> contains a 1 at position <span><math><mi>t</mi><mspace></mspace><mrow><mi>mod</mi></mrow><mspace></mspace><mo>|</mo><mi>τ</mi><mo>(</mo><mi>e</mi><mo>)</mo><mo>|</mo></math></span>. This periodicity allows for a compact representation of infinite TVGs. We prove that even for very simple underlying graphs, i.e., directed and undirected cycles, the problem of deciding whether a cop-winning strategy exists is NP-hard and <span><math><mi>W</mi><mo>[</mo><mn>1</mn><mo>]</mo></math></span>-hard parameterized by the number of vertices. Furthermore, we show that this decision problem can be solved on general edge-periodic graphs in PSPACE. Finally, we present tight bounds on the minimum length of a directed or undirected cycle that guarantees the cycle to be robber-winning.</p></div>","PeriodicalId":50224,"journal":{"name":"Journal of Computer and System Sciences","volume":"144 ","pages":"Article 103534"},"PeriodicalIF":1.1,"publicationDate":"2024-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0022000024000291/pdfft?md5=b5026eb7f4f00c8742c1bca27d3f8d40&pid=1-s2.0-S0022000024000291-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140403344","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":"On kernels for d-path vertex cover","authors":"Radovan Červený,&nbsp;Pratibha Choudhary,&nbsp;Ondřej Suchý","doi":"10.1016/j.jcss.2024.103531","DOIUrl":"10.1016/j.jcss.2024.103531","url":null,"abstract":"<div><p>In this paper we study the kernelization of the <em>d</em>-<span>Path Vertex Cover</span> (<em>d</em>-PVC) problem. Given a graph <em>G</em>, the problem requires finding whether there exists a set of at most <em>k</em> vertices whose removal from <em>G</em> results in a graph that does not contain a path (not necessarily induced) with <em>d</em> vertices. It is known that <em>d</em>-PVC is <span>NP</span>-complete for <span><math><mi>d</mi><mo>≥</mo><mn>2</mn></math></span>. Since the problem generalizes to <em>d</em>-<span>Hitting Set</span>, it is known to admit a kernel with <span><math><mi>O</mi><mo>(</mo><mi>d</mi><msup><mrow><mi>k</mi></mrow><mrow><mi>d</mi></mrow></msup><mo>)</mo></math></span> edges. We improve on this by giving better kernels. Specifically, we give kernels with <span><math><mi>O</mi><mo>(</mo><msup><mrow><mi>k</mi></mrow><mrow><mn>2</mn></mrow></msup><mo>)</mo></math></span> vertices and edges for the cases when <span><math><mi>d</mi><mo>=</mo><mn>4</mn></math></span> and <span><math><mi>d</mi><mo>=</mo><mn>5</mn></math></span>. Further, we give a kernel with <span><math><mi>O</mi><mo>(</mo><msup><mrow><mi>k</mi></mrow><mrow><mn>4</mn></mrow></msup><msup><mrow><mi>d</mi></mrow><mrow><mn>2</mn><mi>d</mi><mo>+</mo><mn>9</mn></mrow></msup><mo>)</mo></math></span> vertices and edges for general <em>d</em>.</p></div>","PeriodicalId":50224,"journal":{"name":"Journal of Computer and System Sciences","volume":"144 ","pages":"Article 103531"},"PeriodicalIF":1.1,"publicationDate":"2024-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140323105","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":"Decidable problems in substitution shifts","authors":"Marie-Pierre Béal ,&nbsp;Dominique Perrin ,&nbsp;Antonio Restivo","doi":"10.1016/j.jcss.2024.103529","DOIUrl":"10.1016/j.jcss.2024.103529","url":null,"abstract":"<div><p>In this paper, we investigate the structure of the most general kind of substitution shifts, including non-minimal ones, and allowing erasing morphisms. We prove the decidability of many properties of these morphisms with respect to the shift space generated by iteration, such as aperiodicity, recognizability and (under an additional assumption) irreducibility, or minimality.</p></div>","PeriodicalId":50224,"journal":{"name":"Journal of Computer and System Sciences","volume":"143 ","pages":"Article 103529"},"PeriodicalIF":1.1,"publicationDate":"2024-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140201967","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":"Packing arc-disjoint cycles in oriented graphs","authors":"Jasine Babu ,&nbsp;Ajay Saju Jacob ,&nbsp;R. Krithika ,&nbsp;Deepak Rajendraprasad","doi":"10.1016/j.jcss.2024.103530","DOIUrl":"10.1016/j.jcss.2024.103530","url":null,"abstract":"<div><p><span>Arc-Disjoint Cycle Packing</span> is a classical <span>NP</span>-complete problem and we study it from two perspectives: (1) by restricting the cycles in the packing to be of a fixed length, and (2) by restricting the inputs to bipartite tournaments. Focusing first on <span>Arc-Disjoint</span> <em>r</em><span>-Cycle Packing</span> (where the cycles in the packing are required to be of length <em>r</em>), we show <span>NP</span>-completeness in oriented graphs with girth <em>r</em> for each <span><math><mi>r</mi><mo>≥</mo><mn>3</mn></math></span> and study the parameterized complexity of the problem with respect to two parameterizations (solution size and vertex cover size) for <span><math><mi>r</mi><mo>=</mo><mn>4</mn></math></span> in oriented graphs. Moving on to <span>Arc-Disjoint Cycle Packing</span> in bipartite tournaments, we show that every bipartite tournament either contains <em>k</em> arc-disjoint cycles or has a feedback arc set of size at most <span><math><mn>7</mn><mo>(</mo><mi>k</mi><mo>−</mo><mn>1</mn><mo>)</mo></math></span>. This result adds to the set of Erdös-Pósa-type results known in the combinatorics literature for packing and covering problems.</p></div>","PeriodicalId":50224,"journal":{"name":"Journal of Computer and System Sciences","volume":"143 ","pages":"Article 103530"},"PeriodicalIF":1.1,"publicationDate":"2024-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140201944","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":"Monitoring the edges of a graph using distances with given girth","authors":"Chenxu Yang ,&nbsp;Gang Yang ,&nbsp;Sun-Yuan Hsieh ,&nbsp;Yaping Mao ,&nbsp;Ralf Klasing","doi":"10.1016/j.jcss.2024.103528","DOIUrl":"10.1016/j.jcss.2024.103528","url":null,"abstract":"<div><p>A set <em>M</em> of vertices of a graph <em>G</em> is a <em>distance-edge-monitoring set</em> if for every edge <span><math><mi>e</mi><mo>∈</mo><mi>G</mi></math></span>, there is a vertex <span><math><mi>x</mi><mo>∈</mo><mi>M</mi></math></span> and a vertex <span><math><mi>y</mi><mo>∈</mo><mi>G</mi></math></span> such that <em>e</em> belongs to all shortest paths between <em>x</em> and <em>y</em>. We denote by <span><math><mrow><mi>dem</mi></mrow><mo>(</mo><mi>G</mi><mo>)</mo></math></span> the smallest size of such a set in <em>G</em>. In this paper, we prove that <span><math><mi>dem</mi><mo>(</mo><mi>G</mi><mo>)</mo><mo>≤</mo><mi>n</mi><mo>−</mo><mo>⌊</mo><mi>g</mi><mo>(</mo><mi>G</mi><mo>)</mo><mo>/</mo><mn>2</mn><mo>⌋</mo></math></span> for any connected graph <em>G</em>, which is not a tree, of order <em>n</em>, where <span><math><mi>g</mi><mo>(</mo><mi>G</mi><mo>)</mo></math></span> is the length of a shortest cycle in <em>G</em>, and give the graphs with <span><math><mi>dem</mi><mo>(</mo><mi>G</mi><mo>)</mo><mo>=</mo><mi>n</mi><mo>−</mo><mo>⌊</mo><mi>g</mi><mo>(</mo><mi>G</mi><mo>)</mo><mo>/</mo><mn>2</mn><mo>⌋</mo></math></span>. We also obtain that <span><math><mo>|</mo><mi>V</mi><mo>(</mo><mi>G</mi><mo>)</mo><mo>|</mo><mo>≥</mo><mi>k</mi><mo>+</mo><mo>⌊</mo><mi>g</mi><mo>(</mo><mi>G</mi><mo>)</mo><mo>/</mo><mn>2</mn><mo>⌋</mo></math></span> for every connected graph <em>G</em> with <span><math><mrow><mi>dem</mi></mrow><mo>(</mo><mi>G</mi><mo>)</mo><mo>=</mo><mi>k</mi></math></span> and <span><math><mi>g</mi><mo>(</mo><mi>G</mi><mo>)</mo><mo>=</mo><mi>g</mi></math></span>. Furthermore, the lower bound holds if and only if <span><math><mi>g</mi><mo>=</mo><mn>3</mn></math></span> and <span><math><mi>k</mi><mo>=</mo><mi>n</mi><mo>−</mo><mn>1</mn></math></span> or <span><math><mi>g</mi><mo>=</mo><mn>4</mn></math></span> and <span><math><mi>k</mi><mo>=</mo><mn>2</mn></math></span>. We prove that <span><math><mrow><mi>dem</mi></mrow><mo>(</mo><mi>G</mi><mo>)</mo><mo>≤</mo><mn>2</mn><mi>n</mi><mo>/</mo><mn>5</mn></math></span> for <span><math><mi>g</mi><mo>(</mo><mi>G</mi><mo>)</mo><mo>≥</mo><mn>5</mn></math></span>.</p></div>","PeriodicalId":50224,"journal":{"name":"Journal of Computer and System Sciences","volume":"143 ","pages":"Article 103528"},"PeriodicalIF":1.1,"publicationDate":"2024-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140053823","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}