Database theory-- ICDT : International Conference ... proceedings. International Conference on Database Theory最新文献_第9页

Front Matter, Table of Contents, Preface, Conference Organization 前文，目录，序言，会议组织

Database theory-- ICDT : International Conference ... proceedings. International Conference on Database Theory Pub Date : 2018-01-01 DOI: 10.4230/LIPIcs.ICDT.2018.0

B. Kimelfeld, Yael Amsterdamer

引用次数: 0

Preserving Constraints with the Stable Chase 用稳定追逐保持约束

Database theory-- ICDT : International Conference ... proceedings. International Conference on Database Theory Pub Date : 2018-01-01 DOI: 10.4230/LIPIcs.ICDT.2018.12

David Carral, M. Krötzsch, Maximilian Marx, A. Ozaki, S. Rudolph

{"title":"Preserving Constraints with the Stable Chase","authors":"David Carral, M. Krötzsch, Maximilian Marx, A. Ozaki, S. Rudolph","doi":"10.4230/LIPIcs.ICDT.2018.12","DOIUrl":"https://doi.org/10.4230/LIPIcs.ICDT.2018.12","url":null,"abstract":"Conjunctive query answering over databases with constraints â€“ also known as (tuple-generating) dependencies â€“ is considered a central database task. To this end, several versions of a construction called chase have been described. Given a set Sigma of dependencies, it is interesting to ask which constraints not contained in Sigma that are initially satisfied in a given database instance are preserved when computing a chase over Sigma. Such constraints are an example for the more general class of incidental constraints, which when added to Sigma as new dependencies do not affect certain answers and might even speed up query answering. After formally introducing incidental constraints, we show that deciding incidentality is undecidable for tuple-generating dependencies, even in cases for which query entailment is decidable. For dependency sets with a finite universal model, the core chase can be used to decide incidentality. For the infinite case, we propose the stable chase, which generalises the core chase, and study its relation to incidental constraints.","PeriodicalId":90482,"journal":{"name":"Database theory-- ICDT : International Conference ... proceedings. International Conference on Database Theory","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81806570","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: 8

Querying the Unary Negation Fragment with Regular Path Expressions 使用正则路径表达式查询一元反分段

Database theory-- ICDT : International Conference ... proceedings. International Conference on Database Theory Pub Date : 2018-01-01 DOI: 10.4230/LIPIcs.ICDT.2018.15

J. C. Jung, C. Lutz, M. Martel, Thomas Schneider

{"title":"Querying the Unary Negation Fragment with Regular Path Expressions","authors":"J. C. Jung, C. Lutz, M. Martel, Thomas Schneider","doi":"10.4230/LIPIcs.ICDT.2018.15","DOIUrl":"https://doi.org/10.4230/LIPIcs.ICDT.2018.15","url":null,"abstract":"The unary negation fragment of first-order logic (UNFO) has recently been proposed as a generalization of modal logic that shares many of its good computational and model-theoretic properties. It is attractive from the perspective of database theory because it can express conjunctive queries (CQs) and ontologies formulated in many description logics (DLs). Both are relevant for ontology-mediated querying and, in fact, CQ evaluation under UNFO ontologies (and thus also under DL ontologies) can be `expressed' in UNFO as a satisfiability problem. In this paper, we consider the natural extension of UNFO with regular expressions on binary relations. The resulting logic UNFOreg can express (unions of) conjunctive two-way regular path queries (C2RPQs) and ontologies formulated in DLs that include transitive roles and regular expressions on roles. Our main results are that evaluating C2RPQs under UNFOreg ontologies is decidable, 2ExpTime-complete in combined complexity, and coNP-complete in data complexity, and that satisfiability in UNFOreg is 2ExpTime-complete, thus not harder than in UNFO.","PeriodicalId":90482,"journal":{"name":"Database theory-- ICDT : International Conference ... proceedings. International Conference on Database Theory","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84801887","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

Connecting Width and Structure in Knowledge Compilation 知识汇编中的连接宽度与结构

Database theory-- ICDT : International Conference ... proceedings. International Conference on Database Theory Pub Date : 2017-09-18 DOI: 10.4230/LIPIcs.ICDT.2018.6

Antoine Amarilli, Mikaël Monet, P. Senellart

{"title":"Connecting Width and Structure in Knowledge Compilation","authors":"Antoine Amarilli, Mikaël Monet, P. Senellart","doi":"10.4230/LIPIcs.ICDT.2018.6","DOIUrl":"https://doi.org/10.4230/LIPIcs.ICDT.2018.6","url":null,"abstract":"Several query evaluation tasks can be done via knowledge compilation: the query result is compiled as a lineage circuit from which the answer can be determined. For such tasks, it is important to leverage some width parameters of the circuit, such as bounded treewidth or pathwidth, to convert the circuit to structured classes, e.g., deterministic structured NNFs (d-SDNNFs) or OBDDs. In this work, we show how to connect the width of circuits to the size of their structured representation, through upper and lower bounds. For the upper bound, we show how bounded-treewidth circuits can be converted to a d-SDNNF, in time linear in the circuit size. Our bound, unlike existing results, is constructive and only singly exponential in the treewidth. We show a related lower bound on monotone DNF or CNF formulas, assuming a constant bound on the arity (size of clauses) and degree (number of occurrences of each variable). Specifically, any d-SDNNF (resp., SDNNF) for such a DNF (resp., CNF) must be of exponential size in its treewidth; and the same holds for pathwidth when compiling to OBDDs. Our lower bounds, in contrast with most previous work, apply to any formula of this class, not just a well-chosen family. Hence, for our language of DNF and CNF, pathwidth and treewidth respectively characterize the efficiency of compiling to OBDDs and (d-)SDNNFs, that is, compilation is singly exponential in the width parameter. We conclude by applying our lower bound results to the task of query evaluation.","PeriodicalId":90482,"journal":{"name":"Database theory-- ICDT : International Conference ... proceedings. International Conference on Database Theory","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89962915","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: 9

Constant Delay Enumeration for FO Queries over Databases with Local Bounded Expansion 局部有界扩展数据库上FO查询的常延迟枚举

Database theory-- ICDT : International Conference ... proceedings. International Conference on Database Theory Pub Date : 2017-03-15 DOI: 10.4230/LIPIcs.ICDT.2017.20

L. Segoufin, Alexandre Vigny

引用次数: 26

Top-k Querying of Unknown Values under Order Constraints (Extended Version) 序约束下未知值的Top-k查询(扩展版)

Database theory-- ICDT : International Conference ... proceedings. International Conference on Database Theory Pub Date : 2017-01-10 DOI: 10.4230/LIPIcs.ICDT.2017.5

Antoine Amarilli, Yael Amsterdamer, T. Milo, P. Senellart

引用次数: 4

The Smart Crowd - Learning from the Ones Who Know (Invited Talk) 聪明人群-向知者学习(特邀演讲)

Database theory-- ICDT : International Conference ... proceedings. International Conference on Database Theory Pub Date : 2017-01-01 DOI: 10.4230/LIPIcs.ICDT.2017.3

T. Milo

{"title":"The Smart Crowd - Learning from the Ones Who Know (Invited Talk)","authors":"T. Milo","doi":"10.4230/LIPIcs.ICDT.2017.3","DOIUrl":"https://doi.org/10.4230/LIPIcs.ICDT.2017.3","url":null,"abstract":"One of the foremost challenges for information technology over the last few years has been to explore, understand, and extract useful information from large amounts of data. Some particular tasks such as annotating data or matching entities have been outsourced to human workers for many years. But the last few years have seen the rise of a new research field called crowdsourcing that aims at delegating a wide range of tasks to human workers, building formal frameworks, and improving the efficiency of these processes. In order to provide sound scientific foundations for crowdsourcing and support the development of efficient crowd sourcing processes, adequate formal models and algorithms must be defined. In particular, the models must formalize unique characteristics of crowd-based settings, such as the knowledge of the crowd and crowd-provided data; the interaction with crowd members; the inherent inaccuracies and disagreements in crowd answers; and evaluation metrics that capture the cost and effort of the crowd. Clearly, what may be achieved with the help of the crowd depends heavily on the properties and knowledge of the given crowd. In this talk we will focus on knowledgeable crowds. We will examine the use of such crowds, and in particular domain experts, for assisting solving data management problems. Specifically we will consider three dimensions of the problem: (1) How domain experts can help in improving the data itself, e.g. by gathering missing data and improving the quality of existing data, (2) How they can assist in gathering meta-data that facilitate improved data processing, and (3) How can we find and identify the most relevant crowd for a given data management task.","PeriodicalId":90482,"journal":{"name":"Database theory-- ICDT : International Conference ... proceedings. International Conference on Database Theory","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74726617","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: 1

Detecting Ambiguity in Prioritized Database Repairing 优先数据库修复中的歧义检测

Database theory-- ICDT : International Conference ... proceedings. International Conference on Database Theory Pub Date : 2017-01-01 DOI: 10.4230/LIPIcs.ICDT.2017.17

B. Kimelfeld, Ester Livshits, L. Peterfreund

{"title":"Detecting Ambiguity in Prioritized Database Repairing","authors":"B. Kimelfeld, Ester Livshits, L. Peterfreund","doi":"10.4230/LIPIcs.ICDT.2017.17","DOIUrl":"https://doi.org/10.4230/LIPIcs.ICDT.2017.17","url":null,"abstract":"In its traditional definition, a repair of an inconsistent database is a consistent database that differs from the inconsistent one in a \"minimal way.\" Often, repairs are not equally legitimate, as it is desired to prefer one over another; for example, one fact is regarded more reliable than another, or a more recent fact should be preferred to an earlier one. Motivated by these considerations, researchers have introduced and investigated the framework of preferred repairs, in the context of denial constraints and subset repairs. There, a priority relation between facts is lifted towards a priority relation between consistent databases, and repairs are restricted to the ones that are optimal in the lifted sense. Three notions of lifting (and optimal repairs) have been proposed: Pareto, global, and completion. In this paper we investigate the complexity of deciding whether the priority relation suffices to clean the database unambiguously, or in other words, whether there is exactly one optimal repair. We show that the different lifting semantics entail highly different complexities. Under Pareto optimality, the problem is coNP-complete, in data complexity, for every set of functional dependencies (FDs), except for the tractable case of (equivalence to) one FD per relation. Under global optimality, one FD per relation is still tractable, but we establish Pi-2-p-completeness for a relation with two FDs. In contrast, under completion optimality the problem is solvable in polynomial time for every set of FDs. In fact, we present a polynomial-time algorithm for arbitrary conflict hypergraphs. We further show that under a general assumption of transitivity, this algorithm solves the problem even for global optimality. The algorithm is extremely simple, but its proof of correctness is quite intricate.","PeriodicalId":90482,"journal":{"name":"Database theory-- ICDT : International Conference ... proceedings. International Conference on Database Theory","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84810643","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: 17

Graphs, Hypergraphs, and the Complexity of Conjunctive Database Queries (Invited Talk) 图、超图和连接数据库查询的复杂性(特邀演讲)

Database theory-- ICDT : International Conference ... proceedings. International Conference on Database Theory Pub Date : 2017-01-01 DOI: 10.4230/LIPIcs.ICDT.2017.2

D. Marx

引用次数: 1

Distributed Query Monitoring through Convex Analysis: Towards Composable Safe Zones 基于凸分析的分布式查询监控:迈向可组合安全区域

Database theory-- ICDT : International Conference ... proceedings. International Conference on Database Theory Pub Date : 2017-01-01 DOI: 10.4230/LIPIcs.ICDT.2017.14

M. Garofalakis, V. Samoladas

{"title":"Distributed Query Monitoring through Convex Analysis: Towards Composable Safe Zones","authors":"M. Garofalakis, V. Samoladas","doi":"10.4230/LIPIcs.ICDT.2017.14","DOIUrl":"https://doi.org/10.4230/LIPIcs.ICDT.2017.14","url":null,"abstract":"Continuous tracking of complex data analytics queries over high-speed distributed streams is becoming increasingly important. Query tracking can be reduced to continuous monitoring of a condition over the global stream. Communication-efficient monitoring relies on locally processing stream data at the sites where it is generated, by deriving site-local conditions which collectively guarantee the global condition. Recently proposed geometric techniques offer a generic approach for splitting an arbitrary global condition into local geometric monitoring constraints (known as “Safe Zones”); still, their application to various problem domains has so far been based on heuristics and lacking a principled, compositional methodology. In this paper, we present the first known formal results on the difficult problem of effective Safe Zone (SZ) design for complex query monitoring over distributed streams. Exploiting tools from convex analysis, our approach relies on an algebraic representation of SZs which allows us to: (1) Formally define the notion of a “good” SZ for distributed monitoring problems; and, most importantly, (2) Tackle and solve the important problem of systematically composing SZs for monitored conditions expressed as Boolean formulas over simpler conditions (for which SZs are known); furthermore, we prove that, under broad assumptions, the composed SZ is good if the component SZs are good. Our results are, therefore, a first step towards a principled compositional solution to SZ design for distributed query monitoring. Finally, we discuss a number of important applications for our SZ design algorithms, also demonstrating how earlier geometric techniques can be seen as special cases of our framework. 1998 ACM Subject Classification H.2.m [Database Management] Miscellaneous, C.2.4 [Computer-Communication Networks] Distributed Systems","PeriodicalId":90482,"journal":{"name":"Database theory-- ICDT : International Conference ... proceedings. International Conference on Database Theory","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78644655","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: 7