Filters








631 Hits in 4.5 sec

An Approach for Normalizing Fuzzy Relational Databases Based on Join Dependency
English

Deepa S
2014 International Journal of Computer Trends and Technology  
Fuzziness in databases is used to denote uncertain or incomplete data. Relational Databases stress on the nature of the data to be certain.  ...  As join dependency implies an multivalued dependency by symmetry the proof of join dependency based normalization is stated from the perspective of multivalued dependency based normalization on fuzzy relational  ...  Examining the nature of fuzziness needs to analyze the possibility of functional dependency and Multivalued Dependency(MVD) existent in the relation schema.  ... 
doi:10.14445/22312803/ijctt-v9p101 fatcat:s7uxlcneqjabfcztjm5wrwhj3e

Fuzzy Subset Dependencies

Jyothi Singaraju
2010 International Journal of Computer Applications  
These multivalued dependencies hold in a projection of a relation but not necessarily in the relation itself.  ...  Similar to classical relational database, a full utilization of fuzzy multivalued dependencies in the design of fuzzy relational databases requires that fuzzy embedded multivalued dependencies(fEmvd) and  ...  Similar to classical relational database [15] , a full utilization of fuzzy multivalued dependencies in the design of fuzzy relational databases requires that fuzzy embedded multivalued dependencies(fEmvds  ... 
doi:10.5120/1305-1646 fatcat:4ghrm6s36ferngr5h64jhph5cq

Page 3191 of Mathematical Reviews Vol. , Issue 88f [page]

1988 Mathematical Reviews  
A. (1-MA) Multivalued dependencies in relational databases and Boolean algebras. Libertas Math. 6 (1986), 183-192. Introduction: “In a previous paper [H. Jurgensen and the author, Inform.  ...  Simovici, Dan A. (1-MAB) Towards an abstract theory of dependency constraints in relational databases.  ... 

Data dependencies in extended possibility-based fuzzy relational databases

Z. M. Ma, W. J. Zhang, W. Y. Ma, F. Mili
2002 International Journal of Intelligent Systems  
Based on the semantic equivalence degree the formal definitions of fuzzy functional dependencies (FFDs) and fuzzy multivalued dependencies (FMVDs) are first introduced to the fuzzy relational databases  ...  , where fuzziness of data appears in attribute values in the form of possibility attributions, as well as resemblance relations in attribute domain elements, called extended possibility-based fuzzy relational  ...  In classic relational databases, multivalued dependencies can be defined as follows. DEFINITION 6.  ... 
doi:10.1002/int.10024 fatcat:2eejfo4sarfa7jfdyif75um4nm

Discovery of multivalued dependencies from relations

Iztok Savnik, Peter A. Flach
2000 Intelligent Data Analysis  
Discovery of multivalued dependencies from database relations is viewed as a search in a hypothesis space de ned according to the generalisation relationship among multivalued dependencies.  ...  Two algorithms for the discovery of multivalued dependencies from relations are presented.  ...  Acknowledgements This work was partially supported by the Esprit Long Term Research Project 20237 (Inductive Logic Programming 2) and the INCO-Copernicus Network of Excellence ILPnet2.  ... 
doi:10.3233/ida-2000-43-403 fatcat:nslzm4mppbd6rkufyglvcej7nq

On learning multivalued dependencies with queries

Víctor Lavín Puente
2011 Theoretical Computer Science  
Data dependencies play an important role in the design of relational databases. There is a strong connection between dependencies and some fragments of the propositional logic.  ...  In particular, functional dependencies are closely related to Horn formulas. Also, multivalued dependencies are characterized in terms of multivalued formulas.  ...  Also, we would like to thank the referees for helping us to improve the paper, particularly, the complexity bounds of the learning algorithms.  ... 
doi:10.1016/j.tcs.2011.01.011 fatcat:rct3xiq5cvchzeewouv76tende

Two-Step Heterogeneous Finite Mixture Model Clustering for Mining Healthcare Databases

Ahmed Najjar, Christian Gagne, Daniel Reinharz
2015 2015 IEEE International Conference on Data Mining  
We are proposing in this paper a methodology for exploring and analyzing such databases, with an application in the specific domain of healthcare data analytics.  ...  This approach is evaluated on a realworld application, the clustering of administrative healthcare databases from Québec, with results illustrating the good performances of the proposed method.  ...  ACKNOWLEDGMENTS This work was funded through grants from the CIHR Institute of Genetics (Canada), CIHR Institute of Health Services Research (Canada), NSERC (Canada), and APOGEE-Net/CanGèneTest.  ... 
doi:10.1109/icdm.2015.70 dblp:conf/icdm/NajjarGR15 fatcat:gq7vigydazeflcinehgmov55qe

On a problem of Fagin concerning multivalued dependencies in relational databases

Sven Hartmann, Sebastian Link
2006 Theoretical Computer Science  
Multivalued dependencies (MVDs) are an important class of relational constraints that is fundamental to relational database design.  ...  The positive solution to this problem gives further insight into the difference between the notions of functional and multivalued dependencies.  ...  Dependencies restrict the set of possible instances of a database schema to those which are considered meaningful for the application in mind.  ... 
doi:10.1016/j.tcs.2005.08.036 fatcat:blloadgce5cn5gfi4deeonsvdi

Axiomatisation of fuzzy rnultivalued dependencies in a fuzzy relational data model

Hồ Thuần, Hồ Cẩm Hà, Huỳnh Văn Nam
2013 Journal of Computer Science and Cybernetics  
The idea of extension of multivalued dependency on fuzzy relational database in [I] is the extension of the equal relation '=' to the relation o-equivalent.  ...  In "Axiomatisation of fuzzy multivalued dependencies in a fuzzy relational data model" [1) , Bhattacharjee and Mazumdar have introduced an extension of classical multivalued dependencies for fuzzy relational  ...  We would like to propose a proof for FMVD5 in general case, by using only the definition of FMVD. FMVD5 Transitivity Proof.  ... 
doi:10.15625/1813-9663/16/4/2915 fatcat:pocp6xv3rnhk7p4fmaaurke6oq

Conceptual Modeling of Geographic Information System Applications [chapter]

Adnan Yazici, Kemal Akkaya
2000 Studies in Fuzziness and Soft Computing  
The types of uncertainty that we mainly focus in this paper are fuzzy, null, and incomplete information related to objects and their properties, classes, and relationships among objects and classes of  ...  that have been difficult to integrate cohesively in simple database models.  ...  Acknowledgements We thank to the anonymous reviewers of this paper for their helpful input.  ... 
doi:10.1007/978-3-7908-1845-1_7 fatcat:wh4mxifhwvd6znucyfe3kw564m

Page 3930 of Mathematical Reviews Vol. , Issue 93g [page]

1993 Mathematical Reviews  
Summary: “This paper deals with the concept of translation of relational schemes for a set of functional, multivalued and join dependencies.  ...  Summary: “A lattice-theoretic approach is developed to study the properties of functional dependencies in relational databases.  ... 

Page 281 of Mathematical Reviews Vol. , Issue 81A [page]

1981 Mathematical Reviews  
S. 81a:68025 “Possiblemembership of a multivalued dependency in a relational database. Inform. Process. Lett. 9 (1979), no. 2, 80-83.  ...  Author’s introduction: “The membership problem of dependencies in relational databases is to determine whether a dependency in a database relation can be derived from a given set of dependencies.  ... 

Page 3738 of Mathematical Reviews Vol. , Issue 81I [page]

1981 Mathematical Reviews  
Hagihara, Kenichi; Ito, Minoru; Taniguchi, Kenichi; Kasami, Tadao Membership problem for multivalued dependencies in relational databases. 811:68033 Systems-Comput.  ...  a relational database and a multivalued dependency set M on the attribute set U, determines whether or not an arbitrarily given multivalued dependency d cap be derived from F U M by a complete set of  ... 

Adequacy of decompositions of relational databases

David Maier, Alberto O. Mendelzon, Fereidoon Sadri, Jeffrey Dullman
1980 Journal of computer and system sciences (Print)  
We show that these notions are equivalent in the case that all constraints in the database are functional dependencies. This result solves an open problem of Rissanen.  ...  The database scheme representing the real world is a collection of (nondisjoint) subsets of the * RELATIONAL DATABASES 369 univesal relation scheme R; each of these subsets is called a relation scheme.  ...  If we are given a set of functional and/or multivalued dependencies D, then we let SAT(D) be the set of relations that satisfy all the dependencies in D, and we take L = SAT(D).  ... 
doi:10.1016/0022-0000(80)90029-x fatcat:zqudsscbuvatrapyabo2hrkc5e

Page 7762 of Mathematical Reviews Vol. , Issue 96m [page]

1996 Mathematical Reviews  
Multivalued database dependencies (mvd’s) have been introduced as a weaker variant of functional dependencies (fd’s).  ...  Embedded multivalued dependencies (emvd’s) are mvd’s on a projection and are a special case of projected join dependencies.  ... 
« Previous Showing results 1 — 15 out of 631 results