{"title":"Resolution-Based Model Construction for PLTL","authors":"Michel Ludwig, U. Hustadt","doi":"10.1109/TIME.2009.11","DOIUrl":"https://doi.org/10.1109/TIME.2009.11","url":null,"abstract":"With tableaux-based reasoning approaches or model checking techniques for propositional linear-time temporal logics, PLTL, it is easily possible to construct counter examples for formulae that are not valid. In contrast, only the information that a formula is satisfiable is usually available in resolution-based inference systems. In this paper we present a resolution-based approach for constructing models for satisfiable PLTL formulae. Our approach is based on using the standard model construction for sets of propositional clauses saturated under ordered resolution in the different time points of a temporal model. The temporal model construction procedure is also designed in such a way that it can be easily implemented in existing theorem rovers for PLTL.","PeriodicalId":163298,"journal":{"name":"2009 16th International Symposium on Temporal Representation and Reasoning","volume":"76 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128008918","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}
Daniele Riboni, L. Pareschi, C. Bettini, S. Jajodia
{"title":"Preserving Anonymity of Recurrent Location-Based Queries","authors":"Daniele Riboni, L. Pareschi, C. Bettini, S. Jajodia","doi":"10.1109/TIME.2009.8","DOIUrl":"https://doi.org/10.1109/TIME.2009.8","url":null,"abstract":"The anonymization of location based queries through the generalization of spatio-temporal information has been proposed as a privacy preserving technique. We show that the presence of multiple concurrent requests, the repetition of similar requests by the same issuers, and the distribution of different service parameters in the requests can significantly affect the level of privacy obtained by current anonymity-based techniques. We provide a formal model of the privacy threat, and we propose an incremental defense technique based on a combination of anonymity and obfuscation. We show the effectiveness of this technique by means of an extensive experimental evaluation.","PeriodicalId":163298,"journal":{"name":"2009 16th International Symposium on Temporal Representation and Reasoning","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114546290","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}
J. McCabe-Dansted, T. French, M. Reynolds, S. Pinchinat
{"title":"On the Expressivity of RoCTL*","authors":"J. McCabe-Dansted, T. French, M. Reynolds, S. Pinchinat","doi":"10.1109/TIME.2009.13","DOIUrl":"https://doi.org/10.1109/TIME.2009.13","url":null,"abstract":"RoCTL* was proposed to model robustness in concurrent systems. RoCTL* extended CTL* with the addition of Obligatory and Robustly operators, which quantify over failure-free paths and paths with one more failure respectively. Whether RoCTL* is more expressive than CTL* has remained an open problem since the RoCTL* logic was proposed. We use the equivalence of LTL to counter-free automata to show that RoCTL* is expressively equivalent to CTL*; the translation to CTL* provides the first model checking procedure for RoCTL*. However, we show that RoCTL* is relatively succinct as all satisfaction preserving translations into CTL* are non-elementary in length.","PeriodicalId":163298,"journal":{"name":"2009 16th International Symposium on Temporal Representation and Reasoning","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116839477","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}
{"title":"Classical and Fuzzy Neighborhood Relations of the Temporal Qualitative Algebra","authors":"S. Badaloni, M. Falda","doi":"10.1109/TIME.2009.10","DOIUrl":"https://doi.org/10.1109/TIME.2009.10","url":null,"abstract":"In this paper we study the problem of representing different forms of imperfect temporal knowledge. Imperfection in knowledge can be present in the forms of coarse knowledge about temporal events or even in the form of incomplete, imprecise, vague or uncertain temporal information. The two orthogonal notions of coarseness and fuzziness seem to be quite adequate to manage these two kinds of temporal ignorance and they can be combined to develop a more general model. The first part of the present study is dedicated to the definition of a new Neighborhood Temporal Qualitative Algebra nQA starting from Freksa's work about Allen's Algebra neighborhood relations. Freksa's Algebra is merged with the Convex Point Algebra and all the neighborhood relations needed to close the nQA Algebra are computed automatically. The Algebra nQA is tractable. In the second part of the paper, the fuzziness notion is considered and combined with that of conceptual neighborhood. The algebra nQAfuz is defined as a fuzzy extension of the algebra nQA, and the conditions of its tractability are studied.","PeriodicalId":163298,"journal":{"name":"2009 16th International Symposium on Temporal Representation and Reasoning","volume":"155 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116905148","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}
{"title":"On First-Order Query Rewriting for Incomplete Database Histories","authors":"V. Bruyère, Alexandre Decan, J. Wijsen","doi":"10.1109/TIME.2009.17","DOIUrl":"https://doi.org/10.1109/TIME.2009.17","url":null,"abstract":"Multiwords are defined as words in which single symbols can be replaced by nonempty sets of symbols. Such a set of symbols captures uncertainty about the exact symbol. Words are obtained from multiwords by selecting a single symbol from every set. A pattern is certain in a multiword W if it occurs in every word that can be obtained from W. For a given pattern, we are interested in finding a logic formula that recognizes the multiwords in which that pattern is certain. This problem can be seen as a special case of consistent query answering (CQA).We show how our results can be applied in CQA on database histories under primary key constraints.","PeriodicalId":163298,"journal":{"name":"2009 16th International Symposium on Temporal Representation and Reasoning","volume":"216 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130107264","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}
{"title":"Event-Oriented Data Models and Temporal Queries in Transaction-Time Databases","authors":"C. Zaniolo","doi":"10.1109/TIME.2009.26","DOIUrl":"https://doi.org/10.1109/TIME.2009.26","url":null,"abstract":"Past research on temporal databases has primarily focused on state-based representations and on relational query language extensions for such representations. This led to many different proposals that had did not succeed in making a significant impact on SQL-compliant DBMS.More recently however, there has been significant interest and progress on event sequences,leading to vendor-proposed extensions of SQL standards for pattern queries based on Kleene-closure expressions.In this paper, we first outline these extensions and their uses in dealing with sequence of events, and then show that they can also be used effectively to express more traditional temporal queries, such as coalescing and joins, on state-based representations.Thus, we propose an approach that takes full advantage of the fact that every state-based representation also has a dual representation based on its start-event and its end-event.","PeriodicalId":163298,"journal":{"name":"2009 16th International Symposium on Temporal Representation and Reasoning","volume":"165 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127557250","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}
{"title":"Positive and Negative Results on the Decidability of the Model-Checking Problem for an Epistemic Extension of Timed CTL","authors":"C. Dima","doi":"10.1109/TIME.2009.21","DOIUrl":"https://doi.org/10.1109/TIME.2009.21","url":null,"abstract":"We present TCTLK, a continuous-time variant of the Computational Tree Logic with knowledge operators, generalizing both TCTL, the continuous-time variant of CTL, and CTLK, the epistemic generalization of CTL.Formulas are interpreted over timed automata, with a synchronous and perfect recall semantics,and the observability relation requires one to specify what clocks are visible for an agent.We show that, in general, the model-checking problem for TCTLK is undecidable, even if formulas do not use any clocks --and hence CTLK has an undecidable model-checking problem when interpreted over timed automata.On the other hand, we show that, when each agent can see all clock values,model-checking becomes decidable.","PeriodicalId":163298,"journal":{"name":"2009 16th International Symposium on Temporal Representation and Reasoning","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126361809","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}
Olaf Beyersdorff, A. Meier, M. Mundhenk, Thomas Schneider, Michael Thomas, H. Vollmer
{"title":"Model Checking CTL is Almost Always Inherently Sequential","authors":"Olaf Beyersdorff, A. Meier, M. Mundhenk, Thomas Schneider, Michael Thomas, H. Vollmer","doi":"10.2168/LMCS-7(2:12)2011","DOIUrl":"https://doi.org/10.2168/LMCS-7(2:12)2011","url":null,"abstract":"The model checking problem for CTL is known to be P-complete (Clarke, Emerson, and Sistla (1986), see Schnoebelen (2002)). We consider fragments of CTL obtained by restricting the use of temporal modalities or the use of negations---restrictions already studied for LTL by Sistla and Clarke (1985) and Markey (2004).For all these fragments, except for the trivial case without any temporal operator, we systematically prove model checking to be either inherently sequential (P-complete) or very efficiently parallelizable (LOGCFL-complete). For most fragments, however, model checking for CTL is already P-complete. Hence our results indicate that in most applications, approaching CTL model checking by parallelism will not result in the desired speed up. We also completely determine the complexity of the model checking problem for all fragments of the extensions ECTL, CTL+, and ECTL+.","PeriodicalId":163298,"journal":{"name":"2009 16th International Symposium on Temporal Representation and Reasoning","volume":"121 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125903370","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}
{"title":"Temporal Relations with Signals: The Case of Italian Temporal Prepositions","authors":"Tommaso Caselli, F. Dell’Orletta, I. Prodanof","doi":"10.1109/TIME.2009.23","DOIUrl":"https://doi.org/10.1109/TIME.2009.23","url":null,"abstract":"This paper presents a Maximum Entropy tagger for the identification of intra-sentential temporal relations between temporal expressions and eventualities mediated by temporal signals in constructions of the kind \"eventuality + signal + temporal relation\". The tagger reports an accuracy rate of 90.8%, outperforming the baseline (81.8%). One of the main results of this work is represented by the identification of a set of robust features which may be automatically obtained with a relative computational effort.","PeriodicalId":163298,"journal":{"name":"2009 16th International Symposium on Temporal Representation and Reasoning","volume":"157 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121679116","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}
{"title":"Simple Algorithm for Simple Timed Games","authors":"Yasmina Abdeddaïm, E. Asarin, M. Sighireanu","doi":"10.1109/TIME.2009.14","DOIUrl":"https://doi.org/10.1109/TIME.2009.14","url":null,"abstract":"We propose a subclass of timed game automata(TGA), called Task TGA, representing networks of communicating tasks where the system can choose when to start the task and the environment can choose the duration of the task. We search to solve finite-horizon reachability games on Task TGA by building strategies in the form of Simple Temporal Networks with Uncertainty (STNU). Such strategies have the advantage of being very succinct due to the partial order reduction of independent tasks.We show that the existence of such strategies is an NP-complete problem. A practical consequence of this result is a fully forward algorithm for building STNU strategies.Potential applications of this work are planning and scheduling under temporal uncertainty.","PeriodicalId":163298,"journal":{"name":"2009 16th International Symposium on Temporal Representation and Reasoning","volume":"37 8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125734207","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}