Results 11 - 20 of 6,107

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
equally well to represent sets and tuples. Such structures allow great flexibility in data representation What query language is appropriate for such structures? Here we propose a simple language UnQL for querying data organized as a rooted, edge-labeled graph. In this model, relational data may

Open information extraction from the web

by Michele Banko, Michael J Cafarella, Stephen Soderland, Matt Broadhead, Oren Etzioni - IN IJCAI , 2007
"... Traditionally, Information Extraction (IE) has focused on satisfying precise, narrow, pre-specified requests from small homogeneous corpora (e.g., extract the location and time of seminars from a set of announcements). Shifting to a new domain requires the user to name the target relations and to ma ..."
Abstract - Cited by 373 (39 self) - Add to MetaCart
of relational tuples without requiring any human input. The paper also introduces TEXTRUNNER, a fully implemented, highly scalable OIE system where the tuples are assigned a probability and indexed to support efficient extraction and exploration via user queries. We report on experiments over a 9,000,000 Web

A Refinement Calculus for Tuple Spaces

by Laura Semini, Carlo Montangero, Laura Semini, Carlo Montangero - Science of Computer Programming , 1999
"... It is fairly accepted that the realization of complex systems must be accomplished step by step from the initial specification, through a sequence of intermediate phases, to the final program. These development steps, linking a preliminary version, or description, of the program to a more detaile ..."
Abstract - Cited by 3 (2 self) - Add to MetaCart
relation between intermediate descriptions, and the rules to check whether the relation is satisfied. Tuple space languages are concurrent languages, that foster the definition of autonomous entities of computation (the processes), and offer mechanisms for their synchronization and communication

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
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

Index Structures for Path Expressions

by Tova Milo, Dan Suciu , 1997
"... In recent years there has been an increased interest in managing data which does not conform to traditional data models, like the relational or object oriented model. The reasons for this non-conformance are diverse. One one hand, data may not conform to such models at the physical level: it may be ..."
Abstract - Cited by 333 (7 self) - Add to MetaCart
and edges to attributes or values. Figure 1 illustrates a semistructured database providing information about a city. Relational databases are traditionally queried with associative queries, retrieving tuples based on the value of some attributes. To answer such queries efciently, database management

Keyword searching and browsing in databases using BANKS

by Gaurav Bhalotia, Arvind Hulgeri, Charuta Nakhe, Soumen Chakrabarti, S. Sudarshan - In ICDE , 2002
"... With the growth of the Web, there has been a rapid increase in the number of users who need to access online databases without having a detailed knowledge of the schema or of query languages; even relatively simple query languages designed for non-experts are too complicated for them. We describe BA ..."
Abstract - Cited by 321 (14 self) - Add to MetaCart
With the growth of the Web, there has been a rapid increase in the number of users who need to access online databases without having a detailed knowledge of the schema or of query languages; even relatively simple query languages designed for non-experts are too complicated for them. We describe

Subtyping recursive types

by Roberto M. Amadio, Luca Cardelli - ACM TRANSACTIONS ON PROGRAMMING LANGUAGES AND SYSTEMS , 1993
"... We investigate the interactions of subtyping and recursive types, in a simply typed λ-calculus. The two fundamental questions here are whether two (recursive) types are in the subtype relation, and whether a term has a type. To address the first question, we relate various definitions of type equiva ..."
Abstract - Cited by 320 (9 self) - Add to MetaCart
We investigate the interactions of subtyping and recursive types, in a simply typed λ-calculus. The two fundamental questions here are whether two (recursive) types are in the subtype relation, and whether a term has a type. To address the first question, we relate various definitions of type

The Revised Report on the Syntactic Theories of Sequential Control and State

by Matthias Felleisen, Robert Hieb - THEORETICAL COMPUTER SCIENCE , 1992
"... The syntactic theories of control and state are conservative extensions of the v -calculus for equational reasoning about imperative programming facilities in higher-order languages. Unlike the simple v -calculus, the extended theories are mixtures of equivalence relations and compatible congruen ..."
Abstract - Cited by 292 (36 self) - Add to MetaCart
The syntactic theories of control and state are conservative extensions of the v -calculus for equational reasoning about imperative programming facilities in higher-order languages. Unlike the simple v -calculus, the extended theories are mixtures of equivalence relations and compatible

A STEP Towards Realizing Codd’s Vision of Rendezvous with the Casual User

by Michael J. Minock , 2007
"... This demonstration showcases the STEP system for natural language access to relational databases. In STEP an administrator authors a highly structured semantic grammar through coupling phrasal patterns to elementary expressions within a decidable fragment of tuple relational calculus. The resulting ..."
Abstract - Cited by 6 (3 self) - Add to MetaCart
This demonstration showcases the STEP system for natural language access to relational databases. In STEP an administrator authors a highly structured semantic grammar through coupling phrasal patterns to elementary expressions within a decidable fragment of tuple relational calculus. The resulting

The logic of constraint satisfaction

by Alan K. Mackworth , 1992
"... The constraint satisfaction problem (CSP) formalization has been a productive tool within Artificial Intelligence and related areas. The finite CSP (FCSP) framework is presented here as a restricted logical calculus within a space of logical representation and reasoning systems. FCSP is formulated i ..."
Abstract - Cited by 265 (5 self) - Add to MetaCart
The constraint satisfaction problem (CSP) formalization has been a productive tool within Artificial Intelligence and related areas. The finite CSP (FCSP) framework is presented here as a restricted logical calculus within a space of logical representation and reasoning systems. FCSP is formulated
Results 11 - 20 of 6,107