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Meijuan zeng

The University of Sydney/John F. Kennedy School at Harvard University, Postgraduate, Graduate Student

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Bachelor of Media Studies from the University of Adelaide, Australia.
Master of Media Studies from the University of Sydney, Australia. Currently also a host for a TV station (but now working behind the scenes).
Phone: +16287892020

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Philippe Lamarre

INSA Lyon

Université Claude Bernard Lyon 1

Nabila Benharkat

INSA Lyon

Frank Le Bourgeois

INSA Lyon

Université Claude Bernard Lyon 1

Université Rennes 2

INSA Lyon

University of East London

Gwen Robbins Schug

University of North Carolina at Greensboro

Gabriel Gutierrez-Alonso

University of Salamanca

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Papers by Meijuan zeng

Exploring Semantic Web Datasets with VisiNav

Database techniques for linked data management

Proceedings of the 2012 international conference on Management of Data - SIGMOD '12, 2012

Linked Data refers to data published in accordance with a number of principles rooted in web stan... more Linked Data refers to data published in accordance with a number of principles rooted in web standards. In the past few years we have witnessed a tremendous growth in Linked Data publishing on the web, leading to tens of billions of data items published online. Querying the data is a key functionality required to make use of the wealth of rich interlinked data. The goal of the tutorial is to introduce, motivate, and detail techniques for querying heterogeneous structured data from across the web. Our tutorial aims to introduce database researchers and practitioners to the new publishing paradigm on the web, and show how the abundance of data published as Linked Data can serve as fertile ground for database research and experimentation. As such, the tutorial focuses on applying database techniques to processing Linked Data, such as optimized indexing and query processing methods in the centralized setting as well as distributed approaches for querying. At the same time, we make the connection from Linked Data best practices to established technologies in distributed databases and the concept of Dataspaces and show differences as well as commonalities between the fields.

Searching and Browsing Linked Data with SWSE: the Semantic Web Search Engine

Web Semantics Science Services and Agents on the World Wide Web, Nov 1, 2012

In this paper, we discuss the architecture and implementation of the Semantic Web Search Engine (... more In this paper, we discuss the architecture and implementation of the Semantic Web Search Engine (SWSE). Following traditional search engine architecture, SWSE consists of crawling, data enhancing, indexing and a user interface for search, browsing and retrieval of information; unlike traditional search engines, SWSE operates over RDF Web dataloosely also known as Linked Data -which implies unique challenges for the system design, architecture, algorithms, implementation and user interface. In particular, many challenges exist in adopting Semantic Web technologies for Web data: the unique challenges of the Web -in terms of scale, unreliability, inconsistency and noise -are largely overlooked by the current Semantic Web standards. Herein, we describe the current SWSE system, initially detailing the architecture and later elaborating upon the function, design, implementation and performance of each individual component. In so doing, we also give an insight into how current Semantic Web standards can be tailored, in a besteffort manner, for use on Web data. Throughout, we offer evaluation and complementary argumentation to support our design choices, and also offer discussion on future directions and open research questions. Later, we also provide candid discussion relating to the difficulties currently faced in bringing such a search engine into the mainstream, and lessons learnt from roughly six years working on the Semantic Web Search Engine project.

On Lightweight Data Summaries for Optimised Query Processing over Linked Data

Typical approaches for querying structured Web Data collect (crawl) and pre-process (index) large... more Typical approaches for querying structured Web Data collect (crawl) and pre-process (index) large amounts of data in a central data repository before allowing for query answering. This time-consuming pre-processing phase however leverages the benefits of Linked Data -where structured data is accessible live and up-to-date at distributed Web resources that may change constantly -only to a limited degree, as query results can never be up-to-date. An ideal query answering system for Linked Data should return current answers in a reasonable amount of time, even on corpora as large as the Web. Query processors evaluating queries directly on the live sources require knowledge of the contents of data sources. In this paper, we develop and evaluate an approximate index structure summarising graph-structured content of sources adhering to Linked Data principles, provide an algorithm for answering conjunctive queries over Linked Data on the Web exploiting the source summary, and evaluate the system using synthetically generated queries. The experimental results show that our lightweight index structure enables complete and up-to-date query results over Linked Data, while keeping the overhead for querying low and providing a satisfying source ranking "for free".

Data summaries for on-demand queries over linked data

Proceedings of the 19th international conference on World wide web - WWW '10, 2010

Typical approaches for querying structured Web Data collect (crawl) and pre-process (index) large... more Typical approaches for querying structured Web Data collect (crawl) and pre-process (index) large amounts of data in a central data repository before allowing for query answering. However, this time-consuming pre-processing phase however leverages the benefits of Linked Data -where structured data is accessible live and up-to-date at distributed Web resources that may change constantly -only to a limited degree, as query results can never be current. An ideal query answering system for Linked Data should return current answers in a reasonable amount of time, even on corpora as large as the Web. Query processors evaluating queries directly on the live sources require knowledge of the contents of data sources. In this paper, we develop and evaluate an approximate index structure summarising graph-structured content of sources adhering to Linked Data principles, provide an algorithm for answering conjunctive queries over Linked Data on the Web exploiting the source summary, and evaluate the system using synthetically generated queries. The experimental results show that our lightweight index structure enables complete and up-to-date query results over Linked Data, while keeping the overhead for querying low and providing a satisfying source ranking at no additional cost.

Linking Semantically-Enabled Online Community Sites

Online community sites have replaced the traditional means of keeping a community informed via li... more Online community sites have replaced the traditional means of keeping a community informed via libraries and publishing. At present, online communities are islands that are not interlinked. We describe different types of online communities and tools that are currently used to build and support such communities. Ontologies and semantic web technologies offer an upgrade path to providing more complex services. Fusing information and inferring links between the various applications and types of information provides relevant insights that make the available information on the Internet more valuable. We present the SIOC ontology which combines terms from vocabularies that already exist with new terms needed to describe the relationships between concepts in the realm of online community sites.

Comparing data summaries for processing live queries over Linked Data

World Wide Web, 2011

A growing amount of Linked Data-graph-structured data accessible at sources distributed across th... more A growing amount of Linked Data-graph-structured data accessible at sources distributed across the Web-enables advanced data integration and decisionmaking applications. Typical systems operating on Linked Data collect (crawl) and pre-process (index) large amounts of data, and evaluate queries against a centralised repository. Given that crawling and indexing are time-consuming operations, the data in the centralised index may be out of date at query execution time. An ideal query answering system for querying Linked Data live should return current answers in a reasonable amount of time, even on corpora as large as the Web. In such a live query system source selection-determining which sources contribute answers to a query-is a crucial step. In this article we propose to use lightweight data summaries for determining relevant sources during query evaluation. We compare several data structures and hash functions with respect to their suitability for building such summaries, stressing benefits for queries that contain joins and require ranking of results and sources. We elaborate on join variants, join ordering and ranking. We analyse the different approaches theoretically and provide results of an extensive experimental evaluation.

On Searching and Displaying RDF Data from the Web

Comparing Major Web Service Paradigms

Challenges Ahead for Converging Financial Data

Future Challenges for Linked APIs

SWSE: Objects before documents!

Web search engines are immensly useful for locating documents online. However, with more and more... more Web search engines are immensly useful for locating documents online. However, with more and more structured data being published online, the restriction to the hyperdocument model impairs the usefulness for searching and browsing. In contrast, an object-orientated model provides means to firstly integrate data about the same object from multiple sources, and secondly enable expressive queries over the integrated information space. We present SWSE, a search engine over 1.1 billion statements published on the Semantic Web. The system provides an easy-to-use end-user interface through which users can find and navigate an object-orientated information space. In addtion, the system exposes the data via a full SPARQL REST service which is open for application developers to query and integrate data in own applications.

D6.1.4 Evaluation of NeOn Components Against Requirements

On-the-fly Integration of Static and Dynamic Sources

Analysing Dependency Dynamics in Web Data

A language-independent method for the extraction of RDF verbalization templates

With the rise of the Semantic Web more and more data become available encoded using the Semantic ... more With the rise of the Semantic Web more and more data become available encoded using the Semantic Web standard RDF. RDF is faced towards machines: designed to be easily processable by machines it is difficult to understand by casual users. Transforming RDF data into human-comprehensible text would facilitate non-experts to assess this information. In this paper we present a languageindependent method for extracting RDF verbalization templates from a parallel corpus of text and data. Our method is based on distant-supervised simultaneous multi relation learning and frequent maximal subgraph pattern mining. We demonstrate the feasibility of our method on a parallel corpus of Wikipedia articles and DBpedia data for English and German.

Searching and browsing Linked Data with SWSE

Web search engines such as Google, Yahoo! MSN/Bing, and Ask are far from the consummate Web searc... more Web search engines such as Google, Yahoo! MSN/Bing, and Ask are far from the consummate Web search solution: they do not typically produce direct answers to queries but instead typically recommend a selection of related documents from the Web. We note that in more recent years, search engines have begun to provide direct answers to prose queries matching certain common templates—for example,“population of china” or “12 euro in dollars”—but again, such functionality is limited to a small subset of popular user ...

Contextually Scoped Negation for Reasoning on the Web

Scoped negation in the context of local-closed world assumption. Basically, you dene the border o... more

Interoperation between Information Spaces on the Web

Abstract. In my thesis I will address the problem of interoperation between information spaces on... more Abstract. In my thesis I will address the problem of interoperation between information spaces on the web. We explain how this problem is dieren t to traditional database integration scenarios. In particular, we focus on one issue of the information integration problem peculiar to the web environment, namely linking information across sources. We use a graph-based data model and representation format, and dene a query and rule language where queries can span multiple sources. We show how such a language can be used to relate information among,sources.

Towards Semantically-Interlinked Online

Exploring Semantic Web Datasets with VisiNav

Database techniques for linked data management

Proceedings of the 2012 international conference on Management of Data - SIGMOD '12, 2012

Linked Data refers to data published in accordance with a number of principles rooted in web stan... more Linked Data refers to data published in accordance with a number of principles rooted in web standards. In the past few years we have witnessed a tremendous growth in Linked Data publishing on the web, leading to tens of billions of data items published online. Querying the data is a key functionality required to make use of the wealth of rich interlinked data. The goal of the tutorial is to introduce, motivate, and detail techniques for querying heterogeneous structured data from across the web. Our tutorial aims to introduce database researchers and practitioners to the new publishing paradigm on the web, and show how the abundance of data published as Linked Data can serve as fertile ground for database research and experimentation. As such, the tutorial focuses on applying database techniques to processing Linked Data, such as optimized indexing and query processing methods in the centralized setting as well as distributed approaches for querying. At the same time, we make the connection from Linked Data best practices to established technologies in distributed databases and the concept of Dataspaces and show differences as well as commonalities between the fields.

Searching and Browsing Linked Data with SWSE: the Semantic Web Search Engine

Web Semantics Science Services and Agents on the World Wide Web, Nov 1, 2012

In this paper, we discuss the architecture and implementation of the Semantic Web Search Engine (... more In this paper, we discuss the architecture and implementation of the Semantic Web Search Engine (SWSE). Following traditional search engine architecture, SWSE consists of crawling, data enhancing, indexing and a user interface for search, browsing and retrieval of information; unlike traditional search engines, SWSE operates over RDF Web dataloosely also known as Linked Data -which implies unique challenges for the system design, architecture, algorithms, implementation and user interface. In particular, many challenges exist in adopting Semantic Web technologies for Web data: the unique challenges of the Web -in terms of scale, unreliability, inconsistency and noise -are largely overlooked by the current Semantic Web standards. Herein, we describe the current SWSE system, initially detailing the architecture and later elaborating upon the function, design, implementation and performance of each individual component. In so doing, we also give an insight into how current Semantic Web standards can be tailored, in a besteffort manner, for use on Web data. Throughout, we offer evaluation and complementary argumentation to support our design choices, and also offer discussion on future directions and open research questions. Later, we also provide candid discussion relating to the difficulties currently faced in bringing such a search engine into the mainstream, and lessons learnt from roughly six years working on the Semantic Web Search Engine project.

On Lightweight Data Summaries for Optimised Query Processing over Linked Data

Typical approaches for querying structured Web Data collect (crawl) and pre-process (index) large... more Typical approaches for querying structured Web Data collect (crawl) and pre-process (index) large amounts of data in a central data repository before allowing for query answering. This time-consuming pre-processing phase however leverages the benefits of Linked Data -where structured data is accessible live and up-to-date at distributed Web resources that may change constantly -only to a limited degree, as query results can never be up-to-date. An ideal query answering system for Linked Data should return current answers in a reasonable amount of time, even on corpora as large as the Web. Query processors evaluating queries directly on the live sources require knowledge of the contents of data sources. In this paper, we develop and evaluate an approximate index structure summarising graph-structured content of sources adhering to Linked Data principles, provide an algorithm for answering conjunctive queries over Linked Data on the Web exploiting the source summary, and evaluate the system using synthetically generated queries. The experimental results show that our lightweight index structure enables complete and up-to-date query results over Linked Data, while keeping the overhead for querying low and providing a satisfying source ranking "for free".

Data summaries for on-demand queries over linked data

Proceedings of the 19th international conference on World wide web - WWW '10, 2010

Typical approaches for querying structured Web Data collect (crawl) and pre-process (index) large... more Typical approaches for querying structured Web Data collect (crawl) and pre-process (index) large amounts of data in a central data repository before allowing for query answering. However, this time-consuming pre-processing phase however leverages the benefits of Linked Data -where structured data is accessible live and up-to-date at distributed Web resources that may change constantly -only to a limited degree, as query results can never be current. An ideal query answering system for Linked Data should return current answers in a reasonable amount of time, even on corpora as large as the Web. Query processors evaluating queries directly on the live sources require knowledge of the contents of data sources. In this paper, we develop and evaluate an approximate index structure summarising graph-structured content of sources adhering to Linked Data principles, provide an algorithm for answering conjunctive queries over Linked Data on the Web exploiting the source summary, and evaluate the system using synthetically generated queries. The experimental results show that our lightweight index structure enables complete and up-to-date query results over Linked Data, while keeping the overhead for querying low and providing a satisfying source ranking at no additional cost.

Linking Semantically-Enabled Online Community Sites

Online community sites have replaced the traditional means of keeping a community informed via li... more Online community sites have replaced the traditional means of keeping a community informed via libraries and publishing. At present, online communities are islands that are not interlinked. We describe different types of online communities and tools that are currently used to build and support such communities. Ontologies and semantic web technologies offer an upgrade path to providing more complex services. Fusing information and inferring links between the various applications and types of information provides relevant insights that make the available information on the Internet more valuable. We present the SIOC ontology which combines terms from vocabularies that already exist with new terms needed to describe the relationships between concepts in the realm of online community sites.

Comparing data summaries for processing live queries over Linked Data

World Wide Web, 2011

A growing amount of Linked Data-graph-structured data accessible at sources distributed across th... more A growing amount of Linked Data-graph-structured data accessible at sources distributed across the Web-enables advanced data integration and decisionmaking applications. Typical systems operating on Linked Data collect (crawl) and pre-process (index) large amounts of data, and evaluate queries against a centralised repository. Given that crawling and indexing are time-consuming operations, the data in the centralised index may be out of date at query execution time. An ideal query answering system for querying Linked Data live should return current answers in a reasonable amount of time, even on corpora as large as the Web. In such a live query system source selection-determining which sources contribute answers to a query-is a crucial step. In this article we propose to use lightweight data summaries for determining relevant sources during query evaluation. We compare several data structures and hash functions with respect to their suitability for building such summaries, stressing benefits for queries that contain joins and require ranking of results and sources. We elaborate on join variants, join ordering and ranking. We analyse the different approaches theoretically and provide results of an extensive experimental evaluation.

On Searching and Displaying RDF Data from the Web

Comparing Major Web Service Paradigms

Challenges Ahead for Converging Financial Data

Future Challenges for Linked APIs

SWSE: Objects before documents!

Web search engines are immensly useful for locating documents online. However, with more and more... more Web search engines are immensly useful for locating documents online. However, with more and more structured data being published online, the restriction to the hyperdocument model impairs the usefulness for searching and browsing. In contrast, an object-orientated model provides means to firstly integrate data about the same object from multiple sources, and secondly enable expressive queries over the integrated information space. We present SWSE, a search engine over 1.1 billion statements published on the Semantic Web. The system provides an easy-to-use end-user interface through which users can find and navigate an object-orientated information space. In addtion, the system exposes the data via a full SPARQL REST service which is open for application developers to query and integrate data in own applications.

D6.1.4 Evaluation of NeOn Components Against Requirements

On-the-fly Integration of Static and Dynamic Sources

Analysing Dependency Dynamics in Web Data

A language-independent method for the extraction of RDF verbalization templates

With the rise of the Semantic Web more and more data become available encoded using the Semantic ... more With the rise of the Semantic Web more and more data become available encoded using the Semantic Web standard RDF. RDF is faced towards machines: designed to be easily processable by machines it is difficult to understand by casual users. Transforming RDF data into human-comprehensible text would facilitate non-experts to assess this information. In this paper we present a languageindependent method for extracting RDF verbalization templates from a parallel corpus of text and data. Our method is based on distant-supervised simultaneous multi relation learning and frequent maximal subgraph pattern mining. We demonstrate the feasibility of our method on a parallel corpus of Wikipedia articles and DBpedia data for English and German.

Searching and browsing Linked Data with SWSE

Web search engines such as Google, Yahoo! MSN/Bing, and Ask are far from the consummate Web searc... more Web search engines such as Google, Yahoo! MSN/Bing, and Ask are far from the consummate Web search solution: they do not typically produce direct answers to queries but instead typically recommend a selection of related documents from the Web. We note that in more recent years, search engines have begun to provide direct answers to prose queries matching certain common templates—for example,“population of china” or “12 euro in dollars”—but again, such functionality is limited to a small subset of popular user ...

Contextually Scoped Negation for Reasoning on the Web

Scoped negation in the context of local-closed world assumption. Basically, you dene the border o... more

Interoperation between Information Spaces on the Web

Abstract. In my thesis I will address the problem of interoperation between information spaces on... more Abstract. In my thesis I will address the problem of interoperation between information spaces on the web. We explain how this problem is dieren t to traditional database integration scenarios. In particular, we focus on one issue of the information integration problem peculiar to the web environment, namely linking information across sources. We use a graph-based data model and representation format, and dene a query and rule language where queries can span multiple sources. We show how such a language can be used to relate information among,sources.

Towards Semantically-Interlinked Online