Article Structure
Abstract
As information extraction (IE) becomes more central to enterprise applications, rule-based IE engines have become increasingly important.
Introduction
In recent years, enterprises have seen the emergence of important text analytics applications like compliance and data redaction.
Grammar-based Systems and CPSL
A cascading grammar consists of a sequence of phases, each of which consists of one or more rules.
SystemT
SystemT is a declarative IE system based on an algebraic framework.
Grammar vs. Algebra
Having described both the traditional cascading grammar approach and the declarative approach
Experimental Evaluation
In this section we present an extensive comparison study between SystemT and implementations of expanded CPSL grammar in terms of quality, runtime performance and resource requirements.
Conclusion
In this paper, we described SystemT, a declarative IE system based on an algebraic framework.
Topics
regular expression
- Figure 3: Regular Expression Extraction OperatorPage 3, “Grammar-based Systems and CPSL”
- 3 illustrates the regular expression extraction operator in the algebra, which performs character-level regular expression matching.Page 3, “SystemT”
- 0 The Extract operator (5) performs character-level operations such as regular expression and dictionary matching over text, creating a tuple for each match.Page 3, “SystemT”
- Character-Level Regular Expression CPSL cannot specify character-level regular expressions that span multiple tokens.Page 6, “Grammar vs. Algebra”
- (b) Example operations supported in AQL that cannot be expressed in expanded code-free CPSL grammars include (i) character-level regular expressions spanning multiple tokens, (ii) counting the number of annotations occurring within a given bounded window and (iii) deleting annotations if they overlap with other annotations starting later in the document.Page 7, “Grammar vs. Algebra”
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NER
- 0 NER : named-entity recognition for Person, Organization, Location, Address, PhoneNumber, EmaiIAddress, URL and DateTime.Page 7, “Experimental Evaluation”
- We chose NER primarily because named-entity recognition is a well-studied problem and standard datasets are available for evaluation.Page 7, “Experimental Evaluation”
- 3To the best of our knowledge, ANNIE (Cunningham et al., 2002) is the only publicly available NER library implemented in a grammar-based system (JAPE in GATE).Page 7, “Experimental Evaluation”
- For this purpose, we have configured both ANNIE and T-NE to identify only the same eight types of entities listed for NER task.Page 8, “Experimental Evaluation”
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rule-based
- As information extraction (IE) becomes more central to enterprise applications, rule-based IE engines have become increasingly important.Page 1, “Abstract”
- In this paper, we describe SystemT, a rule-based IE system whose basic design removes the expressivity and performance limitations of current systems based on cascading grammars.Page 1, “Abstract”
- In recent years, these systemic requirements have led to renewed interest in rule-based IE systems (Doan et al., 2008; SAP, 2010; IBM, 2010; SAS, 2010).Page 1, “Introduction”
- Until recently, rule-based IE systems (Cunningham et al., 2000; Boguraev, 2003; Drozdzynski et al., 2004) were predominantly based on the cascading grammar formalism exemplified by thePage 1, “Introduction”
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