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On the complexity of join dependencies

Marc Gyssens
1986 ACM Transactions on Database Systems  
In [IO] a method is proposed for decomposing join dependencies (jds) in a relational database using the notion of a hinge. This method was subsequently studied in [ll] and [El.  ...  As a consequence, consistency checking can be performed in polynomial time if we restrict aurselves to n-cyclic jds, for a tired value of n, not necessarily equal t" 2.  ...  As a consequence, checking e decomposed database for global consistency can be done in polynomial time if one allows only n-cyclic join dependencies, for a fixed level of cyclicity n, which may be greater  ... 
doi:10.1145/5236.5237 fatcat:6kociyzrpjhuziagi4baselj4y

On the implication problem for probabilistic conditional independency

S.K.M. Wong, C.J. Butz, D. Wu
2000 IEEE transactions on systems, man and cybernetics. Part A. Systems and humans  
Index Terms-Bayesian networks, embedded multivalued dependency, implication problem, probabilistic conditional independence, relational databases.  ...  The implication problem is to test whether a given set of independencies logically implies another independency. This problem is crucial in the design of a probabilistic reasoning system.  ...  We say that a relation satisfies the acyclic join dependency (AJD), if: That is, decomposes losslessly onto . We also write as .  ... 
doi:10.1109/3468.895901 fatcat:c4mshemp35bfhjgfqc5dueohcq

Efficient and optimal query answering on independent schemes

Paolo Atzeni, Edward P.F. Chan
1990 Theoretical Computer Science  
For the class of independent SC .hpmzs, :.x &rive an &cient algorithm ihat generates opiimai unions of simple chase join expressions that computp the total projections with respect to a set of embedded  ...  The total projections of the representative instance have recently been proposed as the basis to generate answers for queries in systems using the Universal Relation Interface.  ...  Sagiv [2l] studied query evaluation in independent schemes when the set of constraints is the union of the full join dependency IN and an embedded cover E The queries are represented as tableaux and are  ... 
doi:10.1016/0304-3975(90)90172-e fatcat:fbtsvpnfundqfnmudjs6vubthm

A Case Study Implementing Features Using AspectJ

Christian Kastner, Sven Apel, Don Batory
2007 11th International Software Product Line Conference (SPLC 2007)  
As the number of aspects in a feature grows, there is a noticeable decrease in code readability and maintainability. Most of the unique and powerful features of AspectJ were not needed.  ...  We evaluate the suitability of AspectJ with respect to this task by a case study that refactors the embedded database system Berkeley DB into 38 features.  ...  We thank Roberto Lopez-Herrejon and Maximilian Störzer for their helpful comments on earlier drafts of the paper. This paper is a condensation of the master's thesis of C. Kästner.  ... 
doi:10.1109/spline.2007.4339271 fatcat:hjvqfmdmwbayrejfncrjiqksse

A Case Study Implementing Features Using AspectJ

Christian Kastner, Sven Apel, Don Batory
2007 11th International Software Product Line Conference (SPLC 2007)  
As the number of aspects in a feature grows, there is a noticeable decrease in code readability and maintainability. Most of the unique and powerful features of AspectJ were not needed.  ...  We evaluate the suitability of AspectJ with respect to this task by a case study that refactors the embedded database system Berkeley DB into 38 features.  ...  We thank Roberto Lopez-Herrejon and Maximilian Störzer for their helpful comments on earlier drafts of the paper. This paper is a condensation of the master's thesis of C. Kästner.  ... 
doi:10.1109/spline.2007.12 dblp:conf/splc/KastnerAB07 fatcat:o5fcd3ar6nb4hfaorpfn6kkwd4

A simplied universal relation assumption and its properties

Ronald Fagin, Alberto O. Mendelzon, Jeffrey D. Ullman
1982 ACM Transactions on Database Systems  
dependencies that includes embedded multivalued dependencies.  ...  We propose a simpler method of describing the real world, where constraints are given by functional dependencies and a single join dependency.  ...  ACKNOWLEDGMENTS The authors are grateful to Catriel Beeri, Maria Klawe, David Maier, and Moshe Vardi for useful suggestions.  ... 
doi:10.1145/319732.319735 fatcat:ixuyssaaq5f7zfw7sqyuopjpie

Algebraic aspects of relational database decomposition

Stephen J. Hegner
1983 Proceedings of the 2nd ACM SIGACT-SIGMOD symposium on Principles of database systems - PODS '83  
An algebraic framework for investigating the problem of decomposing a relational database schema into components is developed.  ...  It is argued that the views of a relational schema which are to be the components of a decomposition should form a finite atomic Boolean algebra. The unit of the  ...  ~~z)AT~(x)AT~(w) =a R(u,y,w)l As we shall see this is the "true" Join dependency which we want for decomposition This modified schema 1s almost what we want for a decomposition For further discussion of  ... 
doi:10.1145/588058.588106 dblp:conf/pods/Hegner83 fatcat:xdy5af2fqzeihalnyzyv3y2goy

Hash-Based Structural Join Algorithms [chapter]

Christian Mathis, Theo Härder
2006 Lecture Notes in Computer Science  
Algorithms for processing Structural Joins embody essential building blocks for XML query evaluation.  ...  Therefore, it is not possible to design the structural join algorithm.  ...  Depending on how a result tuple is constructed, the operators can be assigned to one of the six classes: Full*Join operators return a sequence of joined result tuples just as earlier proposals for structural  ... 
doi:10.1007/11896548_14 fatcat:f6mqon3zbza2jlamagypeqilba

STR2RTS: Refactored StreamIT Benchmarks into Statically Analyzable Parallel Benchmarks for WCET Estimation & Real-Time Scheduling

Benjamin Rouxel, Isabelle Puaut, Marc Herbstritt
2017 Worst-Case Execution Time Analysis  
Each benchmark can be integrated in a full end-to-end empirical method validation protocol on multi-core architecture.  ...  We all had quite a time to find non-proprietary architecture-independent exploitable parallel benchmarks for Worst-Case Execution Time (WCET) estimation and real-time scheduling.  ...  Other studies prefer task set generators for validation, but cannot be used for a full end-to-end experimental validation as they lack source code.  ... 
doi:10.4230/oasics.wcet.2017.1 dblp:conf/wcet/RouxelP17 fatcat:g6gf4xa47zguzb5dntes3ugjwi

On the Desirability of Acyclic Database Schemes

Catriel Beeri, Ronald Fagin, David Maier, Mihalis Yannakakis
1983 Journal of the ACM  
Also given are several eqmvalent characterizations of those sets M of multivalued dependencies such that M is the set of muRlvalued dependencies that are the consequences of a given join dependency.  ...  Several characterizations for a conflict-free (in the sense of Lien) set of muluvalued dependencies are provided.  ...  The authors are grateful to Marc Graham, Maria Klawe, Jeff Ullman, Moshe Vardi, and Carlo Zaniolo for helpful comments.  ... 
doi:10.1145/2402.322389 fatcat:fohuzs2gv5gztpewfyrbyshfy4

Scalable semantic querying of text

Xiaolan Wang, Aaron Feng, Behzad Golshan, Alon Halevy, George Mihaila, Hidekazu Oiwa, Wang-Chiew Tan
2018 Proceedings of the VLDB Endowment  
KOKO is novel in that its extraction language simultaneously supports conditions on the surface of the text and on the structure of the dependency parse tree of sentences, thereby allowing for more refined  ...  To scale up, KOKO exploits a multi-indexing scheme and heuristics for efficient extractions. We extensively evaluate KOKO over publicly available text corpora.  ...  Because rule-based systems do not require training data, they are applicable more broadly and can also be used as a tool for obtaining an initial annotated corpus for weak supervision.  ... 
doi:10.14778/3213880.3213887 fatcat:zdjit73vznaexne7wqf6rmnzum

Graceful database schema evolution

Carlo A. Curino, Hyun J. Moon, Carlo Zaniolo
2008 Proceedings of the VLDB Endowment  
Our PRISM system takes a big first step toward addressing this pressing need by providing: (i) a language of Schema Modification Operators to express concisely complex schema changes, (ii) tools that allow  ...  Wikipedia and its 170+ schema versions provided an invaluable testbed for validating PRISM tools and their ability to support legacy queries.  ...  Acknowledgements The authors would like to thank Alin Deutsch and Letizia Tanca for the numerous in-depth discussions, MyungWon Ham for the support on the experiments, Julie Nguyen and the reviewers for  ... 
doi:10.14778/1453856.1453939 fatcat:3inn5farenhzxl2wmu7ff2eguu

Part-of-Speech Tagging Using Multiview Learning

KyungTae Lim, Jungyeul Park
2020 IEEE Access  
Let us call a word-based character model a method that generates a representation based on a word (i.e., not the full sentence).  ...  For example, given a sentence the fox jumps, a successful POS tagger can predict the as a determiner, fox as a noun, and jumps as a verb.  ... 
doi:10.1109/access.2020.3033979 fatcat:lfso5kfveffk5ncuneitaigwkq

Decision Procedures over Sophisticated Fractional Permissions [chapter]

Xuan Bach Le, Cristian Gherghina, Aquinas Hobor
2012 Lecture Notes in Computer Science  
We develop a set decision procedures over equations drawn from the sophisticated boolean binary tree fractional permission model developed by Dockins et al. [4].  ...  We show how entailment checkers for separation logic with fractional permissions can extract equation systems over fractional shares.  ...  We have developed a solver for the equation systems and proven that the associated problems are decidable.  ... 
doi:10.1007/978-3-642-35182-2_26 fatcat:4hgcbmznwfcr3bkqzrkwifdbum

Modeling structured event streams in system level performance analysis

Simon Perathoner, Tobias Rein, Lothar Thiele, Kai Lampka, Jonas Rox
2010 SIGPLAN notices  
For example, one may first merge a set of given event streams, then process them jointly and finally decompose them into separate streams again.  ...  The proposed technique is strictly compositional, hence highly suited for being embedded into well known performance evaluation frameworks such as Symta/S and MPA (Modular Performance Analysis).  ...  (b) Fork operator for decomposing a structured event stream into n sub-streams.  ... 
doi:10.1145/1755951.1755895 fatcat:cd4vckaxcbaybnaz7jsktexgka
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