Bulletin of the Society of Sea Water Science, Japan最新文献_第6页

Bulletin of the Society of Sea Water Science, Japan Pub Date : 2021-01-01 DOI: 10.4230/LIPIcs.SEA.2021.12

S. Puglisi, Bella Zhukova

{"title":"Document Retrieval Hacks","authors":"S. Puglisi, Bella Zhukova","doi":"10.4230/LIPIcs.SEA.2021.12","DOIUrl":"https://doi.org/10.4230/LIPIcs.SEA.2021.12","url":null,"abstract":"Given a collection of strings, document listing refers to the problem of finding all the strings (or documents) where a given query string (or pattern) appears. Index data structures that support efficient document listing for string collections have been the focus of intense research in the last decade, with dozens of papers published describing exotic and elegant compressed data structures. The problem is now quite well understood in theory and many of the solutions have been implemented and evaluated experimentally. A particular recent focus has been on highly repetitive document collections, which have become prevalent in many areas (such as version control systems and genomics – to name just two very different sources). The aim of this paper is to describe simple and efficient document listing algorithms that can be used in combination with more sophisticated techniques, or as baselines against which the performance of new document listing indexes can be measured. Our approaches are based on simple combinations of scanning and hashing, which we show to combine very well with dictionary compression to achieve small space usage. Our experiments show these methods to be often much faster and less space consuming than the best specialized indexes for the problem.","PeriodicalId":9448,"journal":{"name":"Bulletin of the Society of Sea Water Science, Japan","volume":"65 1","pages":"12:1-12:12"},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82812154","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}

引用次数: 5

How to Find the Exit from a 3-Dimensional Maze 如何从三维迷宫中找到出口

Bulletin of the Society of Sea Water Science, Japan Pub Date : 2021-01-01 DOI: 10.4230/LIPIcs.SEA.2021.21

M. Hermann

引用次数: 0

An Experimental Study of External Memory Algorithms for Connected Components 连接元件外部存储算法的实验研究

Bulletin of the Society of Sea Water Science, Japan Pub Date : 2021-01-01 DOI: 10.4230/LIPIcs.SEA.2021.23

G. Brodal, Rolf Fagerberg, David Hammer, U. Meyer, M. Penschuck, Hung Tran

{"title":"An Experimental Study of External Memory Algorithms for Connected Components","authors":"G. Brodal, Rolf Fagerberg, David Hammer, U. Meyer, M. Penschuck, Hung Tran","doi":"10.4230/LIPIcs.SEA.2021.23","DOIUrl":"https://doi.org/10.4230/LIPIcs.SEA.2021.23","url":null,"abstract":"We empirically investigate algorithms for solving Connected Components in the external memory model. In particular, we study whether the randomized O(Sort(E)) algorithm by Karger, Klein, and Tarjan can be implemented to compete with practically promising and simpler algorithms having only slightly worse theoretical cost, namely Borůvka’s algorithm and the algorithm by Sibeyn and collaborators. For all algorithms, we develop and test a number of tuning options. Our experiments are executed on a large set of different graph classes including random graphs, grids, geometric graphs, and hyperbolic graphs. Among our findings are: The Sibeyn algorithm is a very strong contender due to its simplicity and due to an added degree of freedom in its internal workings when used in the Connected Components setting. With the right tunings, the Karger-Klein-Tarjan algorithm can be implemented to be competitive in many cases. Higher graph density seems to benefit Karger-Klein-Tarjan relative to Sibeyn. Borůvka’s algorithm is not competitive with the two others. 2012 ACM Subject Classification Mathematics of computing → Paths and connectivity problems; Theory of computation → Graph algorithms analysis","PeriodicalId":9448,"journal":{"name":"Bulletin of the Society of Sea Water Science, Japan","volume":"75 1","pages":"23:1-23:23"},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91029855","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}

引用次数: 2

Space and Time Trade-Off for the k Shortest Simple Paths Problem k个最短简单路径问题的时空权衡

Bulletin of the Society of Sea Water Science, Japan Pub Date : 2020-06-16 DOI: 10.4230/LIPICS.SEA.2020.18

Ali Al Zoobi, D. Coudert, N. Nisse

{"title":"Space and Time Trade-Off for the k Shortest Simple Paths Problem","authors":"Ali Al Zoobi, D. Coudert, N. Nisse","doi":"10.4230/LIPICS.SEA.2020.18","DOIUrl":"https://doi.org/10.4230/LIPICS.SEA.2020.18","url":null,"abstract":"The k shortest simple path problem (kSSP) asks to compute a set of top-k shortest simple paths from a vertex s to a vertex t in a digraph. Yen (1971) proposed the first algorithm with the best known theoretical complexity of O(kn(m + n log n)) for a digraph with n vertices and m arcs. Since then, the problem has been widely studied from an algorithm engineering perspective, and impressive improvements have been achieved. In particular, Kurz and Mutzel (2016) proposed a sidetracks-based (SB) algorithm which is currently the fastest solution. In this work, we propose two improvements of this algorithm. We first show how to speed up the SB algorithm using dynamic updates of shortest path trees. We did experiments on some road networks of the 9th DIMAC'S challenge with up to about half a million nodes and one million arcs. Our computational results show an average speed up by a factor of 1.5 to 2 with a similar working memory consumption as SB. We then propose a second algorithm enabling to significantly reduce the working memory at the cost of an increase of the running time (up to two times slower). Our experiments on the same data set show, on average, a reduction by a factor of 1.5 to 2 of the working memory.","PeriodicalId":9448,"journal":{"name":"Bulletin of the Society of Sea Water Science, Japan","volume":"5 1","pages":"18:1-18:13"},"PeriodicalIF":0.0,"publicationDate":"2020-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76952465","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}

引用次数: 5

Probing a Set of Trajectories to Maximize Captured Information 探测一组轨迹以最大化捕获的信息

Bulletin of the Society of Sea Water Science, Japan Pub Date : 2020-04-07 DOI: 10.4230/LIPIcs.SEA.2020.5

S. Fekete, Alexander Hill, Dominik Krupke, Tyler Mayer, Joseph S. B. Mitchell, Ojas D. Parekh, C. Phillips

引用次数: 1

Variable Shift SDD: A More Succinct Sentential Decision Diagram 可变移位SDD:一个更简洁的句子决策图

Bulletin of the Society of Sea Water Science, Japan Pub Date : 2020-04-01 DOI: 10.4230/LIPIcs.SEA.2020.22

Kengo Nakamura, Shuhei Denzumi, Masaaki Nishino

引用次数: 6

Efficient Route Planning with Temporary Driving Bans, Road Closures, and Rated Parking Areas 有效的路线规划与临时驾驶禁令，道路封闭，和额定停车区

Bulletin of the Society of Sea Water Science, Japan Pub Date : 2020-04-01 DOI: 10.4230/LIPIcs.SEA.2020.17

A. Kleff, F. Schulz, Jakob Wagenblatt, Tim Zeitz

{"title":"Efficient Route Planning with Temporary Driving Bans, Road Closures, and Rated Parking Areas","authors":"A. Kleff, F. Schulz, Jakob Wagenblatt, Tim Zeitz","doi":"10.4230/LIPIcs.SEA.2020.17","DOIUrl":"https://doi.org/10.4230/LIPIcs.SEA.2020.17","url":null,"abstract":"We study the problem of planning routes in road networks when certain streets or areas are closed at certain times. For heavy vehicles, such areas may be very large since many European countries impose temporary driving bans during the night or on weekends. In this setting, feasible routes may require waiting at parking areas, and several feasible routes with different trade-offs between waiting and driving detours around closed areas may exist. We propose a novel model in which driving and waiting are assigned abstract costs, and waiting costs are location-dependent to reflect the different quality of the parking areas. Our goal is to find Pareto-optimal routes with regards to arrival time at the destination and total cost. We investigate the complexity of the model and determine a necessary constraint on the cost parameters such that the problem is solvable in polynomial time. We present a thoroughly engineered implementation and perform experiments on a production-grade real world data set. The experiments show that our implementation can answer realistic queries in around a second or less which makes it feasible for practical application.","PeriodicalId":9448,"journal":{"name":"Bulletin of the Society of Sea Water Science, Japan","volume":"268 Pt A 1","pages":"17:1-17:13"},"PeriodicalIF":0.0,"publicationDate":"2020-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90812403","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}

引用次数: 4

An Algorithm for the Exact Treedepth Problem 精确树深问题的一种算法

Bulletin of the Society of Sea Water Science, Japan Pub Date : 2020-04-01 DOI: 10.4230/LIPICS.SEA.2020.19

James Trimble

引用次数: 5

Crystal Structure Prediction via Oblivious Local Search 基于遗忘局部搜索的晶体结构预测

Bulletin of the Society of Sea Water Science, Japan Pub Date : 2020-03-20 DOI: 10.4230/LIPIcs.SEA.2020.21

Dmytro Antypov, Argyrios Deligkas, V. Gusev, M. Rosseinsky, P. Spirakis, Michail Theofilatos

{"title":"Crystal Structure Prediction via Oblivious Local Search","authors":"Dmytro Antypov, Argyrios Deligkas, V. Gusev, M. Rosseinsky, P. Spirakis, Michail Theofilatos","doi":"10.4230/LIPIcs.SEA.2020.21","DOIUrl":"https://doi.org/10.4230/LIPIcs.SEA.2020.21","url":null,"abstract":"We study Crystal Structure Prediction, one of the major problems in computational chemistry. This is essentially a continuous optimization problem, where many different, simple and sophisticated, methods have been proposed and applied. The simple searching techniques are easy to understand, usually easy to implement, but they can be slow in practice. On the other hand, the more sophisticated approaches perform well in general, however almost all of them have a large number of parameters that require fine tuning and, in the majority of the cases, chemical expertise is needed in order to properly set them up. In addition, due to the chemical expertise involved in the parameter-tuning, these approaches can be {em biased} towards previously-known crystal structures. Our contribution is twofold. Firstly, we formalize the Crystal Structure Prediction problem, alongside several other intermediate problems, from a theoretical computer science perspective. Secondly, we propose an oblivious algorithm for Crystal Structure Prediction that is based on local search. Oblivious means that our algorithm requires minimal knowledge about the composition we are trying to compute a crystal structure for. In addition, our algorithm can be used as an intermediate step by {em any} method. Our experiments show that our algorithms outperform the standard basin hopping, a well studied algorithm for the problem.","PeriodicalId":9448,"journal":{"name":"Bulletin of the Society of Sea Water Science, Japan","volume":"15 1","pages":"21:1-21:14"},"PeriodicalIF":0.0,"publicationDate":"2020-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74939231","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}

引用次数: 4

Faster Fully Dynamic Transitive Closure in Practice 更快的全动态传递闭包

Bulletin of the Society of Sea Water Science, Japan Pub Date : 2020-02-03 DOI: 10.4230/LIPIcs.SEA.2020.14

Kathrin Hanauer, M. Henzinger, Christian Schulz

{"title":"Faster Fully Dynamic Transitive Closure in Practice","authors":"Kathrin Hanauer, M. Henzinger, Christian Schulz","doi":"10.4230/LIPIcs.SEA.2020.14","DOIUrl":"https://doi.org/10.4230/LIPIcs.SEA.2020.14","url":null,"abstract":"The fully dynamic transitive closure problem asks to maintain reachability information in a directed graph between arbitrary pairs of vertices, while the graph undergoes a sequence of edge insertions and deletions. The problem has been thoroughly investigated in theory and many specialized algorithms for solving it have been proposed in the last decades. In two large studies [Frigioni ea, 2001; Krommidas and Zaroliagis, 2008], a number of these algorithms have been evaluated experimentally against simple static algorithms for graph traversal, showing the competitiveness and even superiority of the simple algorithms in practice, except for very dense random graphs or very high ratios of queries. A major drawback of those studies is that only small and mostly randomly generated graphs are considered. \u0000In this paper, we engineer new algorithms to maintain all-pairs reachability information which are simple and space-efficient. Moreover, we perform an extensive experimental evaluation on both generated and real-world instances that are several orders of magnitude larger than those in the previous studies. Our results indicate that our new algorithms outperform all state-of-the-art algorithms on all types of input considerably in practice.","PeriodicalId":9448,"journal":{"name":"Bulletin of the Society of Sea Water Science, Japan","volume":"43 1","pages":"14:1-14:14"},"PeriodicalIF":0.0,"publicationDate":"2020-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81435471","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}

引用次数: 11