Method for automatic wrapper repair

• US 7,440,974 B2
• Filed: 12/05/2005
• Issued: 10/21/2008
• Est. Priority Date: 07/18/2002
• Status: Expired due to Fees

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Chidlovskii, Boris
• Primary Examiner(s): ALAM, SHAHID AL
• Application Number:
  US11/295,367
• Publication Number:
  US 20060085468A1
• Time in Patent Office: 1,051 Days
• Field of Search: 707/4, 707/10, 707/102, 707/103.R, 707/2, 707/101, 707/104.1, 707/201, 715/234
• US Class Current: 1/1
• CPC Class Codes: G06F 16/972 Access to data in other repository systems, e.g. legacy data or dynamic Web page generation
• CPC Class Codes: Y10S 707/99931 Database or file accessing
• CPC Class Codes: Y10S 707/99932 Access augmentation or optimizing
• CPC Class Codes: Y10S 707/99942 Manipulating data structure, e.g. compression, compaction, compilation
• CPC Class Codes: Y10S 707/99945 Object-oriented database structure processing
• CPC Class Codes: Y10S 707/99948 Application of database or data structure, e.g. distributed, multimedia, or image

Abstract

A method of information extraction from a Web page using an initial wrapper which has become partially inoperative, wherein the initial wrapper comprises an initial set of rules for extracting information and for assigning labels from a wrapper set of labels to the extracted information, includes using the initial set of rules to extract strings from the Web page parsed in forward direction; analyzing the extracted strings according to the initial set of rules for assigning labels associated with the wrapper; assigning labels to those strings which satisfy the label rules; using the initial set of rules to extract strings from the Web page in backward/(opposite) direction; analyzing the extracted strings according to the set of rules for assigning labels associated with the wrappers; and assigning labels to those unlabeled strings from which satisfy the label rules.

Claims

1. A method of information extraction from a Web page using an initial wrapper which has become partially inoperative, comprising:

wherein the initial wrapper comprises an initial set of rules for extracting information and for assigning labels from a wrapper set of labels to the extracted information;

extracting strings from the Web page parsed in forward direction using the initial set of rules;

analyzing the extracted strings according to the initial set of rules for assigning labels associated with the wrapper;

assigning labels to those strings which satisfy the label rules;

extracting strings from the Web page in backward/(opposite) direction using the initial set of rules;

analyzing the extracted strings according to the set of rules for assigning labels associated with the wrappers; and

assigning labels to those unlabeled strings from which satisfy the label rules;

wherein the initial wrapper W comprises a triple (T, L, R), where T is an input tokenizer, L is a semantic label set and R is a set of extraction rules R={n}, where each rule n, is a triple (p,s,l), where p ε

S^l and s ε

S^u are prefix and suffix, and ε

L.

2. The method of claim 1, further comprising:

classifying the extracted strings based on content features of the labeled extracted strings from the forward direction; and

validating those labeled extracted strings which satisfy the label rules within some first threshold value.

3. The method of claim 2, further comprising:

classifying the extracted strings based on content features of the labeled extracted strings from the backward direction; and

validating those labeled extracted strings which satisfy the label rules within some second threshold value.

4. The method of claim 1, wherein wrapper W parses the Web page from the beginning to the end;

wherein the extraction rules in R comprise;

for a current textual token t, a labeled prefix P of t contains all tokens from the beginning until t, with all previous textual tokens labeled, and S is suffix of t, E=PtS, P ε

Shu l, S ε

S^u, and a Pair (P,S) forms the full context of token t;

comparing P and S to prefixes and suffixes in the extraction rules such that a Pair (P,S) matches a prefix-suffix pair (p,s) of a rule r=(p,s,l), if p is a suffix of P, P =up, and s is a prefix of S=sv, for some labeled u and unlabeled v;

if a match is found, string t is labeled with label l in the rule; and

if no exact rule is found for P and S the wrapper results in an error.