Results 1 - 10 of 1,951

An Expressive Language for Linear Spatial Database Queries (Extended Abstract)

by Luc Vandeurzen, et al.
"... We exhibit a coordinate-based language, called PFOL, which is sound for the linear queries computable in first-order logic over the reals and extends the latter's restriction to linear arithmetic. To evaluate its expressive power, we first consider PFOL-fin, the PFOL queries that compute finite ..."
Abstract - Cited by 12 (1 self) - Add to MetaCart
and the decoding. This result is used (i) to identify a broad, natural class of linear queries expressible in PFOL, highlighting the richness of general PFOL, and (ii) to establish a general theorem about lifting query languages on finite databases to query languages on arbitrary linear databases. This theorem

Querying object-oriented databases

by Michael Kifer, Won Kim, Yehoshua Sagiv - ACM SIGMOD INTERNATIONAL CONFERENCE ON MANAGEMENT OF DATA , 1992
"... We present a novel language for querying object-oriented databases. The language is built around the idea of extended path expressions that substantially generalize [ZAN83], and on an adaptation of the first-order formalization of object-oriented languages from [KW89, KLW90, KW92]. The language inco ..."
Abstract - Cited by 492 (6 self) - Add to MetaCart
We present a novel language for querying object-oriented databases. The language is built around the idea of extended path expressions that substantially generalize [ZAN83], and on an adaptation of the first-order formalization of object-oriented languages from [KW89, KLW90, KW92]. The language

Constraint Query Languages

by Paris C. Kanellakis , Gabriel M. Kuper, Peter Z. Revesz , 1992
"... We investigate the relationship between programming with constraints and database query languages. We show that efficient, declarative database programming can be combined with efficient constraint solving. The key intuition is that the generalization of a ground fact, or tuple, is a conjunction ..."
Abstract - Cited by 372 (43 self) - Add to MetaCart
We investigate the relationship between programming with constraints and database query languages. We show that efficient, declarative database programming can be combined with efficient constraint solving. The key intuition is that the generalization of a ground fact, or tuple, is a conjunction

Access path selection in a relational database management system

by P. Griffiths Selinger, M. M. Astrahan, D. D. Chamberlin, It. A. Lorie, T. G. Price , 1979
"... ABSTRACT: In a high level query and data manipulation language such as SQL, requests are stated non-procedurally, without reference to access paths. This paper describes how System R chooses access paths for both simple (single relation) and complex queries (such as joins), given a user specificatio ..."
Abstract - Cited by 587 (1 self) - Add to MetaCart
ABSTRACT: In a high level query and data manipulation language such as SQL, requests are stated non-procedurally, without reference to access paths. This paper describes how System R chooses access paths for both simple (single relation) and complex queries (such as joins), given a user

A Query Language and Optimization Techniques for Unstructured Data

by Peter Buneman, Susan Davidson, Gerd Hillebrand, Dan Suciu , 1996
"... A new kind of data model has recently emerged in which the database is not constrained by a conventional schema. Systems like ACeDB, which has become very popular with biologists, and the recent Tsimmis proposal for data integration organize data in tree-like structures whose components can be used ..."
Abstract - Cited by 407 (35 self) - Add to MetaCart
be represented as fixed-depth trees, and on such trees UnQL is equivalent to the relational algebra. The novelty of UnQL consists in its programming constructs for arbitrarily deep data and for cyclic structures. While strictly more powerful than query languages with path expressions like XSQL, UnQL can still

Dynamic Queries for Information Exploration: An Implementation and Evaluation

by Christopher Ahlberg, Christopher Williamson, Ben Shneiderman , 1992
"... We designed, implemented and evaluated a new concept for direct manipulation of databases, called dynamic queries, that allows users to formulate queries with graphical widgets, such as sliders. By providing a graphical visualization of the database and search results, users can find trends and exce ..."
Abstract - Cited by 328 (22 self) - Add to MetaCart
to expore the periodic table of elements and search on their properties. 1. INTRODUCTION Mostdatabasesystems require the user to create andformulate a complex query, whichpresumes that the user is familiar with the logical structure of the database [4]. The queries on a database are usually expressed

Relational Queries Computable in Polynomial Time

by Neil Immerman - Information and Control , 1986
"... We characterize the polynomial time computable queries as those expressible in relational calculus plus a least fixed point operator and a total ordering on the universe. We also show that even without the ordering one application of fixed point suffices to express any query expressible with several ..."
Abstract - Cited by 318 (17 self) - Add to MetaCart
Query languages for relational databases have received considerable attention. In 1972 Codd showed that two natural languages for queries -- one algebraic and the other a version of first order predicate calculus -- have identical powers of expressibility, [Cod72]. Query languages which

On the Expressiveness of Linear-Constraint Query Languages for Spatial Databases

by Luc Vandeurzen , Marc Gyssens, Dirk Van Gucht , 1996
"... ..."
Abstract - Cited by 4 (0 self) - Add to MetaCart
Abstract not found

An Introduction to Spatial Database Systems

by Ralf Hartmut Güting - THE VLDB JOURNAL , 1994
"... We propose a definition of a spatial database system as a database system that offers spatial data types in its data model and query language, and supports ..."
Abstract - Cited by 214 (9 self) - Add to MetaCart
We propose a definition of a spatial database system as a database system that offers spatial data types in its data model and query language, and supports

Face recognition by independent component analysis

by Marian Stewart Bartlett, Javier R. Movellan, Terrence J. Sejnowski - IEEE Transactions on Neural Networks , 2002
"... Abstract—A number of current face recognition algorithms use face representations found by unsupervised statistical methods. Typically these methods find a set of basis images and represent faces as a linear combination of those images. Principal component analysis (PCA) is a popular example of such ..."
Abstract - Cited by 348 (5 self) - Add to MetaCart
database under two different architectures, one which treated the images as random variables and the pixels as outcomes, and a second which treated the pixels as random variables and the images as outcomes. The first architecture found spatially local basis images for the faces. The second architecture
Results 1 - 10 of 1,951