{"@context":"https:\/\/schema.org\/","@type":"PublicationVolume","@id":"#volume686","volumeNumber":8081,"name":"Dagstuhl Seminar Proceedings, Volume 8081","dateCreated":"2008-06-16","datePublished":"2008-06-16","isAccessibleForFree":true,"publisher":"Schloss Dagstuhl \u2013 Leibniz-Zentrum f\u00fcr Informatik","isPartOf":{"@type":"Periodical","@id":"#series119","name":"Dagstuhl Seminar Proceedings","issn":"1862-4405","isAccessibleForFree":true,"publisher":"Schloss Dagstuhl \u2013 Leibniz-Zentrum f\u00fcr Informatik","hasPart":"#volume686"},"hasPart":[{"@type":"ScholarlyArticle","@id":"#article2045","name":"08081 Abstracts Collection \u2013 Data Structures","abstract":"From February 17th to 22nd 2008, the Dagstuhl Seminar 08081 ``Data Structures'' was held in the International Conference and Research Center (IBFI),\r\nSchloss Dagstuhl. It brought together 49 researchers from four continents to discuss recent developments concerning data structures in terms of research but also in terms of new technologies that impact how data can be stored, updated,\r\nand retrieved.\r\nDuring the seminar a fair number of participants presented their current\r\nresearch. There was discussion of ongoing work, and in addition an open problem\r\nsession was held. This paper first describes the seminar topics and goals in general, then gives the minutes of the open problem session, and concludes with\r\nabstracts of the presentations given during the seminar. \r\nWhere appropriate and available, links to extended abstracts or full papers are provided.","keywords":["Data structures","information retrieval","complexity","algorithms","flash memory"],"author":[{"@type":"Person","name":"Arge, Lars","givenName":"Lars","familyName":"Arge"},{"@type":"Person","name":"Sedgewick, Robert","givenName":"Robert","familyName":"Sedgewick"},{"@type":"Person","name":"Seidel, Raimund","givenName":"Raimund","familyName":"Seidel"}],"position":1,"pageStart":1,"pageEnd":18,"dateCreated":"2008-06-16","datePublished":"2008-06-16","isAccessibleForFree":true,"license":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/legalcode","copyrightHolder":[{"@type":"Person","name":"Arge, Lars","givenName":"Lars","familyName":"Arge"},{"@type":"Person","name":"Sedgewick, Robert","givenName":"Robert","familyName":"Sedgewick"},{"@type":"Person","name":"Seidel, Raimund","givenName":"Raimund","familyName":"Seidel"}],"copyrightYear":"2008","accessMode":"textual","accessModeSufficient":"textual","creativeWorkStatus":"Published","inLanguage":"en-US","sameAs":"https:\/\/doi.org\/10.4230\/DagSemProc.08081.1","publisher":"Schloss Dagstuhl \u2013 Leibniz-Zentrum f\u00fcr Informatik","isPartOf":"#volume686"},{"@type":"ScholarlyArticle","@id":"#article2046","name":"Kinetic kd-Trees and Longest-Side kd-Trees","abstract":"We propose a simple variant of kd-trees, called rank-based kd-trees, for sets of points in~$Reals^d$.\r\nWe show that a rank-based kd-tree, like an ordinary kd-tree, supports range search que-ries in~$O(n^{1-1\/d}+k)$ time,\r\nwhere~$k$ is the output size. The main advantage of rank-based kd-trees is that they can be efficiently kinetized:\r\nthe KDS processes~$O(n^2)$ events in the worst case, assuming that the points follow constant-degree algebraic trajectories,\r\neach event can be handled in~$O(log n)$ time, and each point is involved in~$O(1)$ certificates.\r\n\r\nWe also propose a variant of longest-side kd-trees, called rank-based longest-side kd-trees (RBLS kd-trees, for short),\r\nfor sets of points in~$Reals^2$. RBLS kd-trees can be kinetized efficiently as well and like longest-side kd-trees,\r\nRBLS kd-trees support nearest-neighbor, farthest-neighbor, and approximate range search queries in~$O((1\/epsilon)log^2 n)$ time.\r\nThe KDS processes~$O(n^3log n)$ events in the worst case, assuming that the points follow constant-degree algebraic trajectories;\r\neach event can be handled in~$O(log^2 n)$ time, and each point is involved in~$O(log n)$ certificates.","keywords":["Kinetic data structures","kd-tree","longest-side kd-tree"],"author":[{"@type":"Person","name":"Abam, Mohammad","givenName":"Mohammad","familyName":"Abam"},{"@type":"Person","name":"de Berg, Mark","givenName":"Mark","familyName":"de Berg"},{"@type":"Person","name":"Speckmann, Bettina","givenName":"Bettina","familyName":"Speckmann"}],"position":2,"pageStart":1,"pageEnd":12,"dateCreated":"2008-06-16","datePublished":"2008-06-16","isAccessibleForFree":true,"license":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/legalcode","copyrightHolder":[{"@type":"Person","name":"Abam, Mohammad","givenName":"Mohammad","familyName":"Abam"},{"@type":"Person","name":"de Berg, Mark","givenName":"Mark","familyName":"de Berg"},{"@type":"Person","name":"Speckmann, Bettina","givenName":"Bettina","familyName":"Speckmann"}],"copyrightYear":"2008","accessMode":"textual","accessModeSufficient":"textual","creativeWorkStatus":"Published","inLanguage":"en-US","sameAs":"https:\/\/doi.org\/10.4230\/DagSemProc.08081.2","publisher":"Schloss Dagstuhl \u2013 Leibniz-Zentrum f\u00fcr Informatik","isPartOf":"#volume686"},{"@type":"ScholarlyArticle","@id":"#article2047","name":"Optimal Speedup on a Low-Degree Multi-Core Parallel Architecture (LoPRAM)","abstract":"We propose a new model with small degreee of parallelism that reflects current and future multicore architectures in practice. The model is based on the PRAM architecture and hence it inherits many of its interesting theoretical properties. The key observations and differences are that the degree of parallelism (i.e. number of processors or cores) is bounded by O(log n), the synchronization model is looser and the use of parallelism is at a higher level unless explicitly specified otherwise. Surprisingly, these three rather minor variants result in a model in which obtaining work optimal algorithms is significantly easier than for the PRAM. \r\n\r\nThe new model is called Low-degree PRAM or LoPRAM for short. Lastly we observe that there are thresholds in complexity of programming at p=O(log n) and p=O(sqrt(n)) and provide references for specific problems for which this threshold has been formally proven.","keywords":["PRAM","multicore architectures","parallelism","algorithms","dynamic programming","divide and conquer"],"author":[{"@type":"Person","name":"Lopez-Ortiz, Alejandro","givenName":"Alejandro","familyName":"Lopez-Ortiz"},{"@type":"Person","name":"Dorrigiv, Reza","givenName":"Reza","familyName":"Dorrigiv"},{"@type":"Person","name":"Salinger, Alejandro","givenName":"Alejandro","familyName":"Salinger"}],"position":3,"pageStart":1,"pageEnd":13,"dateCreated":"2008-06-16","datePublished":"2008-06-16","isAccessibleForFree":true,"license":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/legalcode","copyrightHolder":[{"@type":"Person","name":"Lopez-Ortiz, Alejandro","givenName":"Alejandro","familyName":"Lopez-Ortiz"},{"@type":"Person","name":"Dorrigiv, Reza","givenName":"Reza","familyName":"Dorrigiv"},{"@type":"Person","name":"Salinger, Alejandro","givenName":"Alejandro","familyName":"Salinger"}],"copyrightYear":"2008","accessMode":"textual","accessModeSufficient":"textual","creativeWorkStatus":"Published","inLanguage":"en-US","sameAs":"https:\/\/doi.org\/10.4230\/DagSemProc.08081.3","publisher":"Schloss Dagstuhl \u2013 Leibniz-Zentrum f\u00fcr Informatik","isPartOf":"#volume686"},{"@type":"ScholarlyArticle","@id":"#article2048","name":"Sources of Superlinearity in Davenport-Schinzel Sequences","abstract":"A {em generalized} Davenport-Schinzel sequence is one over a finite alphabet\r\nthat contains no subsequences isomorphic to a fixed {em forbidden subsequence}.\r\nOne of the fundamental problems in this area is bounding (asymptotically) \r\nthe maximum length of such sequences.\r\nFollowing Klazar, let $Ex(sigma,n)$ be the maximum length of a sequence over an alphabet\r\nof size $n$ avoiding subsequences isomorphic to $sigma$.\r\nIt has been proved that for every $sigma$,\r\n$Ex(sigma,n)$ is either linear or very close to linear; in particular it is \r\n$O(n2^{alpha(n)^{O(1)}})$, where $alpha$ is the inverse-Ackermann function and $O(1)$\r\ndepends on $sigma$. However, very little is known about the properties\r\nof $sigma$ that induce superlinearity of $Ex(sigma,n)$.\r\n\r\nIn this paper we exhibit an infinite family of independent superlinear forbidden subsequences.\r\nTo be specific, we show that there are 17 {em prototypical} superlinear forbidden \r\nsubsequences, some of which can be made arbitrarily long \r\nthrough a simple padding operation.\r\nPerhaps the most novel part of our constructions is a new succinct code for\r\nrepresenting superlinear forbidden subsequences.","keywords":["Davenport-Schinzel Sequences","lower envelopes","splay trees"],"author":{"@type":"Person","name":"Pettie, Seth","givenName":"Seth","familyName":"Pettie"},"position":4,"pageStart":1,"pageEnd":14,"dateCreated":"2008-06-16","datePublished":"2008-06-16","isAccessibleForFree":true,"license":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/legalcode","copyrightHolder":{"@type":"Person","name":"Pettie, Seth","givenName":"Seth","familyName":"Pettie"},"copyrightYear":"2008","accessMode":"textual","accessModeSufficient":"textual","creativeWorkStatus":"Published","inLanguage":"en-US","sameAs":"https:\/\/doi.org\/10.4230\/DagSemProc.08081.4","publisher":"Schloss Dagstuhl \u2013 Leibniz-Zentrum f\u00fcr Informatik","isPartOf":"#volume686"}]}