1,912 Hits in 5.4 sec

A Relational Algebra as a Query Language for Temporal DATALOG [chapter]

Mehmet A. Orgun, William W. Wadge
1992 Database and Expert Systems Applications  
Users query temporal deductive databases using a temporal relational algebra (TRA), which is a pointwise extension of the relational algebra.  ...  This paper introduces a temporal relational algebra as a query language for temporal deductive databases, i.e., Temporal Datalog programs.  ...  Lee for his helpful comments on an earlier draft of this article.  ... 
doi:10.1007/978-3-7091-7557-6_48 fatcat:hnfzpzl4lzgltfds4g7jr25tr4

Incorporating an implicit time dimension into the relational model and algebra

Mehmet Ali Orgun
1996 RAIRO - Theoretical Informatics and Applications  
Thanks are also due to two anonymous référées, for their helpful comments and suggestions, and Joey Paquet for translating the abstract into French.  ...  ACKNOWLEDGEMENTS This work has been supported in part by a Macquarie University Research Grant (MURG). The work has benefited from discussions with Rajiv Bagai, Lee Flax, and Bill Wadge.  ...  As a query language for the model, we introducé a temporal (relational) algebra, which we call TRA, as a point-wise extension of the relational algebra.  ... 
doi:10.1051/ita/1996300302311 fatcat:bhdjvyi5y5b7ffa6kwecp7nc7m

Inference of active transcriptional networks by integration of gene expression kinetics modeling and multisource data

Tra Thi Vu, Jiri Vohradsky
2009 Genomics  
A recursive model of gene expression allowing for identification of active gene expression control networks with up to two regulators of one target gene is presented.  ...  A set of the most probable networks was suggested and analyzed.  ...  [30] and a newer dataset published by th hthreshold value for ChIP-on-chip data (matrix A,B). th rthreshold value for data computed using kinetic model from Eqs.  ... 
doi:10.1016/j.ygeno.2009.01.006 pmid:19442636 fatcat:m3q74kqmmffbnhqywwj3ozixhu

Temporal Logic & Historical Databases

Dov M. Gabbay, Peter McBrien
1991 Very Large Data Bases Conference  
We review attempts at defining a general extension to the relational algebra to incl udc temporal semantics, and dcfinc two temporal operators to achieve a temporal relational algebra with a close correspondence  ...  We then dcmonstratc how this temporal relational algebra may IO ;I limited extent be encoded in standard rclaticlnal algebra, and in turn show how an extcntlcd temporal SQL may be encoded in standard SQL  ...  suggestions for improvements to the final version of the paper.  ... 
dblp:conf/vldb/GabbayM91 fatcat:6dv3wnptojchrbn4fdlixy3je4

Page 5751 of Mathematical Reviews Vol. , Issue 97I [page]

1997 Mathematical Reviews  
Temporal databases are queried using a temporal relation algebra (TRA) which extends the relation algebra point-wise on the set of natural numbers.  ...  In temporal semantics, a time-varying relation is an indexed collection of ordinary rela- tions, one for each moment in time, and a temporal database is modeled by a collection of time-varying relations  ... 

Page 1188 of Mathematical Reviews Vol. , Issue 97B [page]

1997 Mathematical Reviews  
The algebraic front-end, called TRA, is a point-wise extension of the relational algebra upon the set of natural numbers.  ...  “A modular extension of Temporal Datalog is also proposed, through which temporal relations created during the evaluation of TRA expressions may be fed back to the deductive part for further manipulation  ... 

Retrieval Optimization Technique for Tuple Timestamp Historical Relation Temporal Data Model

2012 Journal of Computer Science  
Results: A technique for querying temporal database modeled by TTHR is the topic of this study.  ...  TRA is involved to help querying temporal database that is modeled using Tuple Timestamp Historical Relation (TTHR) Model.  ...  Literature Review MATERIALS AND METHODS Temporal Relational Algebra (TRA): TRA is a set of temporal specific operators which helps writing logical expressions for querying temporal database; in addition  ... 
doi:10.3844/jcssp.2012.243.250 fatcat:5ndxopi7erdjbndq5v2jg24ycy

Nonlinear differential equation model for quantification of transcriptional regulation applied to microarray data of Saccharomyces cerevisiae

Tra Thi Vu, Jiri Vohradsky
2006 Nucleic Acids Research  
This study presents a dynamic model of gene expression which allows for identification of transcriptional regulators using time series of gene expression.  ...  The goal is to apply the model to putative regulators to estimate the transcription pattern of a target gene using a least squares minimization procedure.  ...  ACKNOWLEDGEMENTS The authors wish to thank Josef Panek for useful discussions.  ... 
doi:10.1093/nar/gkl1001 pmid:17170011 pmcid:PMC1802551 fatcat:fbvnbe7cwve5ngc7yojvnhhhaq

Querying Evolving Graphs with Portal [article]

Vera Zaychik Moffitt, Julia Stoyanovich
2016 arXiv   pre-print
We present a compositional temporal graph algebra TGA, and show a reduction of TGA to temporal relational algebra with graph-specific primitives.  ...  This paper proposes a logical model of an evolving graph called a TGraph, which captures evolution of graph topology and of its vertex and edge attributes.  ...  Our data model is based on the temporal relational model, and our algebra corresponds to temporal relational algebra, but is designed specifically for evolving graphs.  ... 
arXiv:1602.00773v2 fatcat:m7wtcfastbhdjjyh67drfttwcu

Table of Contents

2012 Journal of Computer Science and Cybernetics  
A new method for solving the fuzzy model problem base on hedge algebra.  ...  . , Dȃ . ng Vȃn Dú . c -Mô hình da . i số quan hê . cu 'a hê . thống hu .ó. ng dối tu . o . . ng. A relational algebraical model of object oriented systems.  ... 
doi:10.15625/1813-9663/21/3/1252 fatcat:6zdz6c36izek5px2i2y4cjsen4

Navigational XPath

Balder ten Cate, Maarten Marx
2007 SIGMOD record  
We survey expressivity results for navigational fragments of XPath 1.0 and 2.0, as well as Regular XPath ≈ . We also investigate algebras for these fragments.  ...  We are grateful to Loredana Afanasiev and Tadeusz Litak for helpful comments. Balder ten Cate is supported by NWO research grant 639.021.508.  ...  8 binary relations corresponding to the different axes, as well a "unary" relation for each of the different tag names), the situation is a bit different: on this restricted class of models TRA and CRA  ... 
doi:10.1145/1328854.1328858 fatcat:kjouhgo2pnhftj26aj5vzovxhe

On completeness of historical relational query languages

James Clifford, Albert Croker, Alexander Tuzhilin
1994 ACM Transactions on Database Systems  
In Section 3 we examine the temporally ungrouped models, and define three different languages for them: a temporal logic, a logic with explicit reference to time, and a temporal algebra.  ...  For the ungrouped models we define three different languages, a temporal logic, a logic with explicit reference to time, and a temporal algebra, and show that under certain assumptions all three are equivalent  ...  The Because TRA is equivalent to standard relational algebra, the question of its completeness, as in the case of TRDM, is reduced to the question of the completeness of relational algebra.  ... 
doi:10.1145/174638.174642 fatcat:vqxh3ucj2vefphtbaz5wyjlcxa

Symbolic Computation of Maximal Probabilisti Reachability [chapter]

Marta Kwiatkowska, Gethin Norman, Jeremy Sproston
2001 Lecture Notes in Computer Science  
to obtain a model for an infinite-state probabilistic system called a symbolic probabilistic system.  ...  We extend the framework of symbolic transition systems, which equips an infinite-state system with an algebra of symbolic operators on its state space, with a symbolic encoding of probabilistic transitions  ...  Now let be a binary relation on the state space S of P such that s t implies, for all aTra and s ∈ δ a (s), there exists t ∈ δ a (t) such that s t . We call such a relation a typed simulation.  ... 
doi:10.1007/3-540-44685-0_12 fatcat:pwmnsjbtnzc4venxbjbceqoxae

Completeness results for two-sorted metric temporal logics [chapter]

Angelo Montanari, Maarten Rijke
1995 Lecture Notes in Computer Science  
Temporal logic has been successfully used for modeling and analyzing the behavior of reactive and concurrent systems.  ...  This is overcome by metric temporal logics which offer a uniform logical framework in which both qualitative and quantitative timing properties can be expressed by making use of a parameterized operator  ...  We turn a two-sorted frame ~ into a two-sorted model by adding an interpretation for our algebraic terms, and a valuation for atomic temporal formulae.  ... 
doi:10.1007/3-540-60043-4_66 fatcat:hsr3ats2izawdhx6zjil4bn4zq

Energy efficiency in an integrated agro-ecosystem within an acidic soil area of the Mekong Delta, Vietnam

Nguyen Thi Thu Thao, Tra Van Tung, Nguyen Thi Phuong Thao, Son Le Thanh, Sibylle Braunegg, Gerhart Braunegg, Hans Schnitzer, Le Thanh Hai
2020 Energy, Sustainability and Society  
For development of an integrated ecological system aiming towards zero emissions, the analytical methods of material cycles and energy flows utilized a set of indicators of resource efficiency in a sustainable  ...  Background Both exergy and energy analysis methodologies are used for analysing energy efficiencies in various processes, including agriculture.  ...  TVT and a group of coworkers at IER were the site engineers who brought the system into application in a household farm at Long An province, Mekong Delta area, VN.  ... 
doi:10.1186/s13705-020-00265-2 fatcat:tx3ym7rg6veivc2eek7ro7fska
« Previous Showing results 1 — 15 out of 1,912 results