Exploiting Time-based Synonyms in Searching Document Archives - PowerPoint PPT Presentation

Outline Exploiting Time-based Synonyms in Searching Document Archives Nattiya Kanhabua and Kjetil Nørvåg Database System Group Norwegian University of Science and Technology Trondheim, Norway JCDL ’2010, June 21 - 25, Gold Coast, Australia Kanhabua and Nørvåg Exploiting Time-based Synonyms in Search

Outline Outline 1 Introduction Problem Statement Contributions 2 Synonym Detection Entity Recognition and Synonym Extraction Improving the Accuracy of Time Query Expansion 3 Time-based Synonyms Ranking Time-independent Synonyms Ranking Time-dependent Synonyms 4 Evaluation Experiment Setting Experimental Results 5 Conclusions Conclusions and Future Work Kanhabua and Nørvåg Exploiting Time-based Synonyms in Search

Outline Outline 1 Introduction Problem Statement Contributions 2 Synonym Detection Entity Recognition and Synonym Extraction Improving the Accuracy of Time Query Expansion 3 Time-based Synonyms Ranking Time-independent Synonyms Ranking Time-dependent Synonyms 4 Evaluation Experiment Setting Experimental Results 5 Conclusions Conclusions and Future Work Kanhabua and Nørvåg Exploiting Time-based Synonyms in Search

Outline Outline 1 Introduction Problem Statement Contributions 2 Synonym Detection Entity Recognition and Synonym Extraction Improving the Accuracy of Time Query Expansion 3 Time-based Synonyms Ranking Time-independent Synonyms Ranking Time-dependent Synonyms 4 Evaluation Experiment Setting Experimental Results 5 Conclusions Conclusions and Future Work Kanhabua and Nørvåg Exploiting Time-based Synonyms in Search

Outline Outline 1 Introduction Problem Statement Contributions 2 Synonym Detection Entity Recognition and Synonym Extraction Improving the Accuracy of Time Query Expansion 3 Time-based Synonyms Ranking Time-independent Synonyms Ranking Time-dependent Synonyms 4 Evaluation Experiment Setting Experimental Results 5 Conclusions Conclusions and Future Work Kanhabua and Nørvåg Exploiting Time-based Synonyms in Search

Outline Outline 1 Introduction Problem Statement Contributions 2 Synonym Detection Entity Recognition and Synonym Extraction Improving the Accuracy of Time Query Expansion 3 Time-based Synonyms Ranking Time-independent Synonyms Ranking Time-dependent Synonyms 4 Evaluation Experiment Setting Experimental Results 5 Conclusions Conclusions and Future Work Kanhabua and Nørvåg Exploiting Time-based Synonyms in Search

Introduction Synonym Detection Problem Statement Query Expansion Contributions Evaluation Conclusions Outline 1 Introduction Problem Statement Contributions 2 Synonym Detection Entity Recognition and Synonym Extraction Improving the Accuracy of Time Query Expansion 3 Time-based Synonyms Ranking Time-independent Synonyms Ranking Time-dependent Synonyms 4 Evaluation Experiment Setting Experimental Results 5 Conclusions Conclusions and Future Work Kanhabua and Nørvåg Exploiting Time-based Synonyms in Search

Introduction Synonym Detection Problem Statement Query Expansion Contributions Evaluation Conclusions Problem statement In recent years, document archives are publicly available E.g., Internet Archive, digital libraries and news archives Searching in such resources is not straightforward Contents in these resources are strongly time-dependent Query “Pope Benedict XVI” and dates “before 2005” Unable to retrieve documents about “Joseph Alois Ratzinger” To improve the retrieval effectiveness, query expansion using synonyms wrt. time can be employed Kanhabua and Nørvåg Exploiting Time-based Synonyms in Search

Introduction Synonym Detection Problem Statement Query Expansion Contributions Evaluation Conclusions Problem statement In recent years, document archives are publicly available E.g., Internet Archive, digital libraries and news archives Searching in such resources is not straightforward Contents in these resources are strongly time-dependent Query “Pope Benedict XVI” and dates “before 2005” Unable to retrieve documents about “Joseph Alois Ratzinger” To improve the retrieval effectiveness, query expansion using synonyms wrt. time can be employed Kanhabua and Nørvåg Exploiting Time-based Synonyms in Search

Introduction Synonym Detection Problem Statement Query Expansion Contributions Evaluation Conclusions Problem statement In recent years, document archives are publicly available E.g., Internet Archive, digital libraries and news archives Searching in such resources is not straightforward Contents in these resources are strongly time-dependent Query “Pope Benedict XVI” and dates “before 2005” Unable to retrieve documents about “Joseph Alois Ratzinger” To improve the retrieval effectiveness, query expansion using synonyms wrt. time can be employed Kanhabua and Nørvåg Exploiting Time-based Synonyms in Search

Introduction Synonym Detection Problem Statement Query Expansion Contributions Evaluation Conclusions Observation Named entities (people, organization, location, etc.) constitute a major fraction of queries [Sanderson SIGIR’2008] Very dynamic in appearance, i.e., relationships between terms changes over time E.g. changes of roles, name alterations, or semantic shift Synonyms are different words with similar meanings In our context, synonyms are terms used as name variants (other names, titles, or roles) of a named entity E.g., “Cardinal Joseph Ratzinger” is a synonym of “Pope Benedict XVI” before 2005 Kanhabua and Nørvåg Exploiting Time-based Synonyms in Search

Introduction Synonym Detection Problem Statement Query Expansion Contributions Evaluation Conclusions Observation Named entities (people, organization, location, etc.) constitute a major fraction of queries [Sanderson SIGIR’2008] Very dynamic in appearance, i.e., relationships between terms changes over time E.g. changes of roles, name alterations, or semantic shift Synonyms are different words with similar meanings In our context, synonyms are terms used as name variants (other names, titles, or roles) of a named entity E.g., “Cardinal Joseph Ratzinger” is a synonym of “Pope Benedict XVI” before 2005 Kanhabua and Nørvåg Exploiting Time-based Synonyms in Search

Introduction Synonym Detection Problem Statement Query Expansion Contributions Evaluation Conclusions Observation Named entities (people, organization, location, etc.) constitute a major fraction of queries [Sanderson SIGIR’2008] Very dynamic in appearance, i.e., relationships between terms changes over time E.g. changes of roles, name alterations, or semantic shift Synonyms are different words with similar meanings In our context, synonyms are terms used as name variants (other names, titles, or roles) of a named entity E.g., “Cardinal Joseph Ratzinger” is a synonym of “Pope Benedict XVI” before 2005 Kanhabua and Nørvåg Exploiting Time-based Synonyms in Search

Introduction Synonym Detection Problem Statement Query Expansion Contributions Evaluation Conclusions What are time-based synonyms? Time-independent synonyms are invariant to time Time-dependent synonyms are relevant to a particular time period, i.e., entity-synonym relationships change over time Kanhabua and Nørvåg Exploiting Time-based Synonyms in Search

Introduction Synonym Detection Problem Statement Query Expansion Contributions Evaluation Conclusions Application News archive search Search terms are named entities Publication dates of documents are temporal criteria Kanhabua and Nørvåg Exploiting Time-based Synonyms in Search

Introduction Synonym Detection Problem Statement Query Expansion Contributions Evaluation Conclusions Application News archive search Search terms are named entities Publication dates of documents are temporal criteria Scenario 1 Query: “Pope Benedict XVI” and written before 2005 Documents about “Joseph Alois Ratzinger” are relevant Kanhabua and Nørvåg Exploiting Time-based Synonyms in Search

Introduction Synonym Detection Problem Statement Query Expansion Contributions Evaluation Conclusions Application News archive search Search terms are named entities Publication dates of documents are temporal criteria Scenario 2 Query: “Hillary R. Clinton” and written from 1997 to 2002 Documents about “New York Senator” and “First Lady of the United States” are relevant Kanhabua and Nørvåg Exploiting Time-based Synonyms in Search

Introduction Synonym Detection Problem Statement Query Expansion Contributions Evaluation Conclusions Application News archive search Search terms are named entities Publication dates of documents are temporal criteria Challenge Semantic gaps in searching archives, or a lack of knowledge about a query and synonyms at particular time Kanhabua and Nørvåg Exploiting Time-based Synonyms in Search

Introduction Synonym Detection Problem Statement Query Expansion Contributions Evaluation Conclusions Outline 1 Introduction Problem Statement Contributions 2 Synonym Detection Entity Recognition and Synonym Extraction Improving the Accuracy of Time Query Expansion 3 Time-based Synonyms Ranking Time-independent Synonyms Ranking Time-dependent Synonyms 4 Evaluation Experiment Setting Experimental Results 5 Conclusions Conclusions and Future Work Kanhabua and Nørvåg Exploiting Time-based Synonyms in Search