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Join operations in temporal databases

Dengfeng Gao, Christian S. Jensen, Richard T. Snodgrass, Michael D. Soo
2005 The VLDB journal  
First, conventional techniques are designed for the evaluation of joins with equality predicates rather than the inequality predicates prevalent in valid-time queries.  ...  In a temporal database, the problem is more acute for two reasons.  ...  We also thank Wei Li and Joseph Dunn for their help in implementing the temporal join algorithms.  ... 
doi:10.1007/s00778-003-0111-3 fatcat:lgdvkgkftzglbodt3jlx5jtrra

Schema Vacuuming in Temporal Databases

J.F. Roddick
2009 IEEE Transactions on Knowledge and Data Engineering  
Because data are never deleted, only superceded, temporal databases are inherently append-only, resulting, over time, in a large historical sequence of database states.  ...  Temporal databases facilitate the support of historical information by providing functions for indicating the intervals during which a tuple was applicable (along one or more temporal dimensions).  ...  ACKNOWLEDGMENTS The author would like to thank his colleagues with the School of Computer Science, Engineering and Mathematics, Flinders University, for discussions on this topic over a long period of  ... 
doi:10.1109/tkde.2008.201 fatcat:dprk2giwwvbrffg6mjua3zuclm

On periodicity in temporal databases

Alexander Tuzhilin, James Clifford
1995 Information Systems  
in the literature of temporal databases.  ...  The issue of periodicity is generally understood to be a desirable property of temporal data that should be supported by temporal database models and their query languages.  ...  Acknowledgments The authors would like to thank the reviewers for their valuable comments which have helped to improve the presentation of this paper.  ... 
doi:10.1016/0306-4379(95)00034-8 fatcat:rmnfyr34ybgcjeabssq2wxjwuu

Representation of temporal indeterminacy in clinical databases

M J O'Connor, S W Tu, M A Musen
2000 Proceedings. AMIA Symposium  
Temporal indeterminancy is common in clinical medicine because the time of many clinical events is frequently not precisely known.  ...  We have implemented a temporal query system called Tzolkin that provides extensive support for the temporal indeterminancies found in clinical medicine, and have integrated this support with our temporal  ...  Acknowledgements This work has been supported, in part, by grant LM05708 from the National Library of Medicine, and by a grant FastTrack Systems, Inc.  ... 
pmid:11079957 pmcid:PMC2243750 fatcat:rkfspvw6tvcgtbx44hpewhloh4

Supporting temporal text-containment queries in temporal document databases

Kjetil Nørvåg
2004 Data & Knowledge Engineering  
Three of the alternatives have been implemented in the V2 temporal document database system, and the performance of the index structures is studied using temporal web data.  ...  The results show that even a very simple time-indexing approach can reduce query cost by up to three orders of magnitude.  ...  Acknowledgments Many of the basic ideas of this paper were developed during the 9 months the author spent as an ERCIM fellow in the Verso group at INRIA, France, in 2001.  ... 
doi:10.1016/j.datak.2003.08.006 fatcat:r3fvfsyjxrf2fkkej3jyak2ikm

Discovering during-temporal patterns (DTPs) in large temporal databases☆

L ZHANG, G CHEN, T BRIJS, X ZHANG
2008 Expert systems with applications  
Large temporal Databases (TDBs) usually contain a wealth of data about temporal events.  ...  Results from synthetic reveal that the algorithm is efficient and linearly scalable with regard to the number of temporal events.  ...  On the other hand, both Rainsford [3] and Hoppner [6] have recently discussed the issues of finding temporal relationships between time-interval-based events using temporal comparison predicates [  ... 
doi:10.1016/j.eswa.2006.12.024 fatcat:htbmofa5rfhtvdlhlw5dzknwba

Support of Temporal Data in Database Systems

Dušan Petković
2016 International Journal of Computer Applications  
The time is generally a challenging task. All issues in relation to time can be better supported using temporal data models.  ...  Almost all enterprise database systems have implemented temporal data, partly according to the model specified in the SQL:2011 standard and partly according to other, older temporal models.  ...  Transaction time concerns the time when an event was present in the database as stored data. Therefore, transaction time of an event presents the correct database image of the modelled world.  ... 
doi:10.5120/ijca2016911786 fatcat:7b5gn7qv3fee7okbi7yndgumq4

Implementing Temporal Databases in Object-Oriented Systems

A. Steiner, M. C. Norrie
1997 Database Systems for Advanced Applications '97  
A comparison of the two resulting systems highlights the current limitations to the notions of extensibility supported in existing OODBMS.  ...  We then show how equivalent temporal constructs and operations could be provided in existing object-oriented database management systems (OODBMS) and describe how we did this in the 02 system.  ...  To store valid time data, two additional attributes of a type Date, The same can be done for transaction time. In this paper, we concentrate on how to extend data structures with valid time.  ... 
doi:10.1142/9789812819536_0040 fatcat:vwxiclhkkrayndd24ddjn5jkyy

Querying Mobile Objects in Spatio-Temporal Databases [chapter]

Kriengkrai Porkaew, Iosif Lazaridis, Sharad Mehrotra
2001 Lecture Notes in Computer Science  
In dynamic spatio-temporal environments where objects may continuously move in space, maintaining consistent information about the location of objects and processing motion-specific queries is a challenging  ...  In this paper, we focus on indexing and query processing techniques for mobile objects.  ...  [O.t s , O.t e ] represents the valid time interval of the motion.  ... 
doi:10.1007/3-540-47724-1_4 fatcat:cgu3t7r3rbeyjlz36bkod3c6ri

Approximate entity extraction in temporal databases

Wei Lu, Gabriel Pui Cheong Fung, Xiaoyong Du, Xiaofang Zhou, Lijiang Chen, Ke Deng
2011 World wide web (Bussum)  
How to properly define the similarity of each entity in the temporal .cn issues a search query for an entity, he or she is prone to mix up information of the same entity at different time points.  ...  We study the problem of efficiently extracting K entities, in a temporal database, which are most similar to a given search query.  ...  entity extraction in temporal databases.  ... 
doi:10.1007/s11280-011-0109-5 fatcat:4lhee52wnfc7tgc6wugfjriuhq

Temporal semantic assumptions and their use in databases

C. Bettini, X.S. Wang, S. Jajodia
1998 IEEE Transactions on Knowledge and Data Engineering  
Temporal data explicitly stored in a temporal database are often associated with certain semantic assumptions.  ...  Rather than leaving the task of deriving possibly in nite implicit data to application programs, as is the case currently, it is desirable that this be handled by the database management systems.  ...  Here and in the rest of the paper timestamps represent valid time; extensions to include transaction time and other temporal dimensions are not considered.  ... 
doi:10.1109/69.683757 fatcat:gwz72tzievgbbjqxdywzi237ie

Time-parameterized queries in spatio-temporal databases

Yufei Tao, Dimitris Papadias
2002 Proceedings of the 2002 ACM SIGMOD international conference on Management of data - SIGMOD '02  
Time-parameterized queries (TP queries for short) retrieve (i) the actual result at the time that the query is issued, (ii) the validity period of the result given the current motion of the query and the  ...  database objects, and (iii) the change that causes the expiration of the result.  ...  A major difference from continuous queries in the context of traditional databases, is that in case of spatio-temporal databases, the object's dynamic behavior does not necessarily require updates, but  ... 
doi:10.1145/564691.564730 dblp:conf/sigmod/TaoP02 fatcat:h7uf4hpbqfanvolo45kdnjpteq

Time-parameterized queries in spatio-temporal databases

Yufei Tao, Dimitris Papadias
2002 Proceedings of the 2002 ACM SIGMOD international conference on Management of data - SIGMOD '02  
Time-parameterized queries (TP queries for short) retrieve (i) the actual result at the time that the query is issued, (ii) the validity period of the result given the current motion of the query and the  ...  database objects, and (iii) the change that causes the expiration of the result.  ...  A major difference from continuous queries in the context of traditional databases, is that in case of spatio-temporal databases, the object's dynamic behavior does not necessarily require updates, but  ... 
doi:10.1145/564728.564730 fatcat:rkdumy7nzrbj3gj6iax4njfksi

Granularity reduction in temporal document databases

Kjetil Nørvåg
2006 Information Systems  
Three of the strategies have been implemented in the V2 temporal document database system, and in this context we discuss the cost of applying the strategies.  ...  In temporal document databases on the other hand, it is often more appropriate to remove intermediate versions instead of removing the oldest versions. We call this operation granularity reduction.  ...  Acknowledgments This work was done when the author visited Athens University of Economics and Business in 2002, and Aalborg University in 2003, supported by grant #145196/432 from the Norwegian Research  ... 
doi:10.1016/j.is.2004.10.002 fatcat:wawm6wd5kzbefmdsao4xehssne

Aspects of Dealing with Imperfect Data in Temporal Databases [chapter]

José Pons, Christophe Billiet, Olga Pons, Guy De Tré
2013 Studies in Computational Intelligence  
Modelling these kinds of objects or concepts in a (relational) database schema is possible, but time-variant and time-related attributes have an impact on the consistency of the entire database.  ...  In this chapter, an overview is given, concerning the basic concepts and issues related to the modelling of time as such or in (relational) database models and the imperfections that may arise during or  ...  Acknowledgements Part of this research is supported by the grant BES-2009-013805 within the research project TIN2008-02066: Fuzzy Temporal Information treatment in relational DBMS.  ... 
doi:10.1007/978-3-319-00954-4_9 fatcat:fefzey5i45gf7kcgzgzil25yyu
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