Information Processing Letters
Decidable optimization problems for database logic programs
STOC '88 Proceedings of the twentieth annual ACM symposium on Theory of computing
Logic programming and databases
Logic programming and databases
Handbook of theoretical computer science (vol. B)
Graph rewriting: an algebraic and logic approach
Handbook of theoretical computer science (vol. B)
PODS '97 Proceedings of the sixteenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Handbook of formal languages, vol. 1
Handbook of formal languages, vol. 3
Languages, automata, and logic
Handbook of formal languages, vol. 3
Managing semistructured data with florid: a deductive object-oriented perspective
Information Systems - Special issue on semistructured data
Computational problems related to the design of normal form relational schemas
ACM Transactions on Database Systems (TODS)
The theory of joins in relational databases
ACM Transactions on Database Systems (TODS)
Testing implications of data dependencies
ACM Transactions on Database Systems (TODS)
Regular path queries with constraints
Journal of Computer and System Sciences
Expressive and efficient pattern languages for tree-structured data (extended abstract)
PODS '00 Proceedings of the nineteenth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Building intelligent web applications using lightweight wrappers
Data & Knowledge Engineering - Special issue on heterogeneous information resources need semantic access
Datalog LITE: a deductive query language with linear time model checking
ACM Transactions on Computational Logic (TOCL)
Expressiveness of structured document query languages based on attribute grammars
Journal of the ACM (JACM)
On the power of walking for querying tree-structured data
Proceedings of the twenty-first ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Foundations of Databases: The Logical Level
Foundations of Databases: The Logical Level
Query automata over finite trees
Theoretical Computer Science
Introduction To Automata Theory, Languages, And Computation
Introduction To Automata Theory, Languages, And Computation
DEByE - Date extraction by example
Data & Knowledge Engineering
A Query Translation Scheme for Rapid Implementation of Wrappers
DOOD '95 Proceedings of the Fourth International Conference on Deductive and Object-Oriented Databases
Monadic Queries over Tree-Structured Data
LICS '02 Proceedings of the 17th Annual IEEE Symposium on Logic in Computer Science
The Complexity of First-Order and Monadic Second-Order Logic Revisited
LICS '02 Proceedings of the 17th Annual IEEE Symposium on Logic in Computer Science
Characterizing Regular Languages with Polynomial Densities
MFCS '92 Proceedings of the 17th International Symposium on Mathematical Foundations of Computer Science
Visual Web Information Extraction with Lixto
Proceedings of the 27th International Conference on Very Large Data Bases
XPath Containment in the Presence of Disjunction, DTDs, and Variables
ICDT '03 Proceedings of the 9th International Conference on Database Theory
Query Evaluation on Compressed Trees (Extended Abstract)
LICS '03 Proceedings of the 18th Annual IEEE Symposium on Logic in Computer Science
XWRAP: An XML-Enabled Wrapper Construction System for Web Information Sources
ICDE '00 Proceedings of the 16th International Conference on Data Engineering
Containment and equivalence for a fragment of XPath
Journal of the ACM (JACM)
Efficient algorithms for processing XPath queries
VLDB '02 Proceedings of the 28th international conference on Very Large Data Bases
Logic-based web information extraction
ACM SIGMOD Record
The Lixto data extraction project: back and forth between theory and practice
PODS '04 Proceedings of the twenty-third ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Conjunctive queries over trees
PODS '04 Proceedings of the twenty-third ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
ACM Transactions on Database Systems (TODS) - Special Issue: SIGMOD/PODS 2004
Conjunctive queries over trees
Journal of the ACM (JACM)
On the expressive power of monadic least fixed point logic
Theoretical Computer Science - Automata, languages and programming: Logic and semantics (ICALP-B 2004)
Processing queries on tree-structured data efficiently
Proceedings of the twenty-fifth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Forward node-selecting queries over trees
ACM Transactions on Database Systems (TODS)
Journal of Computer and System Sciences
Tight lower bounds for query processing on streaming and external memory data
Theoretical Computer Science
Monadic datalog over finite structures with bounded treewidth
Proceedings of the twenty-sixth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
XCentric: logic programming for XML processing
Proceedings of the 9th annual ACM international workshop on Web information and data management
Theoretical Computer Science
Generating Specialized Rules and Programs for Demand-Driven Analysis
AMAST 2008 Proceedings of the 12th international conference on Algebraic Methodology and Software Technology
ACM Computing Surveys (CSUR)
Reasoning about XML with Temporal Logics and Automata
LPAR '08 Proceedings of the 15th International Conference on Logic for Programming, Artificial Intelligence, and Reasoning
Monadic Datalog Tree Transducers
LATA '09 Proceedings of the 3rd International Conference on Language and Automata Theory and Applications
The finite model theory toolbox of a database theoretician
Proceedings of the twenty-eighth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Compact Representation for Answer Sets of n-ary Regular Queries
CIAA '09 Proceedings of the 14th International Conference on Implementation and Application of Automata
The mathematical morpho-logical view on reasoning about space
IJCAI'07 Proceedings of the 20th international joint conference on Artifical intelligence
A multiagent knowledge and information network approach for managing research assets
Expert Systems with Applications: An International Journal
Efficient and expressive tree filters
FSTTCS'07 Proceedings of the 27th international conference on Foundations of software technology and theoretical computer science
Monadic datalog over finite structures of bounded treewidth
ACM Transactions on Computational Logic (TOCL)
Compact representation for answer sets of n-ary regular queries
Theoretical Computer Science
Probabilistic XML via Markov Chains
Proceedings of the VLDB Endowment
On the equivalence of distributed systems with queries and communication
Proceedings of the 14th International Conference on Database Theory
The OXPath to success in the deep web
Proceedings of the 20th international conference companion on World wide web
The model checking problem for prefix classes of second-order logic: a survey
Fields of logic and computation
FroCoS'11 Proceedings of the 8th international conference on Frontiers of combining systems
A logical toolbox for ontological reasoning
ACM SIGMOD Record
Combining temporal logics for querying XML documents
ICDT'07 Proceedings of the 11th international conference on Database Theory
Integrating semi-structured data into business applications: a web intelligence example
WM'05 Proceedings of the Third Biennial conference on Professional Knowledge Management
Matching with regular constraints
LPAR'05 Proceedings of the 12th international conference on Logic for Programming, Artificial Intelligence, and Reasoning
Logics for unranked trees: an overview
ICALP'05 Proceedings of the 32nd international conference on Automata, Languages and Programming
Tight lower bounds for query processing on streaming and external memory data
ICALP'05 Proceedings of the 32nd international conference on Automata, Languages and Programming
A formal comparison of visual web wrapper generators
SOFSEM'06 Proceedings of the 32nd conference on Current Trends in Theory and Practice of Computer Science
OTM'06 Proceedings of the 2006 international conference on On the Move to Meaningful Internet Systems: AWeSOMe, CAMS, COMINF, IS, KSinBIT, MIOS-CIAO, MONET - Volume Part I
Web and semantic web query languages: a survey
Proceedings of the First international conference on Reasoning Web
XSym'05 Proceedings of the Third international conference on Database and XML Technologies
Logic wrappers and XSLT transformations for tuples extraction from HTML
XSym'05 Proceedings of the Third international conference on Database and XML Technologies
The lixto project: exploring new frontiers of web data extraction
BNCOD'06 Proceedings of the 23rd British National Conference on Databases, conference on Flexible and Efficient Information Handling
Chapter 6: web data extraction for service creation
Search Computing
Exploiting bounded treewidth with datalog (a survey)
Datalog'10 Proceedings of the First international conference on Datalog Reloaded
Datalog-Related aspects in lixto visual developer
Datalog'10 Proceedings of the First international conference on Datalog Reloaded
Datalog relaunched: simulation unification and value invention
Datalog'10 Proceedings of the First international conference on Datalog Reloaded
Datalog+/-: a family of languages for ontology querying
Datalog'10 Proceedings of the First international conference on Datalog Reloaded
Deciding twig-definability of node selecting tree automata
Proceedings of the 15th International Conference on Database Theory
Proceedings of the VLDB Endowment
Recursive queries on trees and data trees
Proceedings of the 16th International Conference on Database Theory
Trial for RDF: adapting graph query languages for RDF data
Proceedings of the 32nd symposium on Principles of database systems
Flag & check: data access with monadically defined queries
Proceedings of the 32nd symposium on Principles of database systems
On the equivalence of distributed systems with queries and communication
Journal of Computer and System Sciences
Hi-index | 0.01 |
Research on information extraction from Web pages (wrapping) has seen much activity recently (particularly systems implementations), but little work has been done on formally studying the expressiveness of the formalisms proposed or on the theoretical foundations of wrapping. In this paper, we first study monadic datalog over trees as a wrapping language. We show that this simple language is equivalent to monadic second order logic (MSO) in its ability to specify wrappers. We believe that MSO has the right expressiveness required for Web information extraction and propose MSO as a yardstick for evaluating and comparing wrappers. Along the way, several other results on the complexity of query evaluation and query containment for monadic datalog over trees are established, and a simple normal form for this language is presented. Using the above results, we subsequently study the kernel fragment Elog− of the Elog wrapping language used in the Lixto system (a visual wrapper generator). Curiously, Elog− exactly captures MSO, yet is easier to use. Indeed, programs in this language can be entirely visually specified.