Results 1 - 10
of
739
Dbpedia spotlight: Shedding light on the web of documents
- In Proceedings of the 7th International Conference on Semantic Systems (I-Semantics
, 2011
"... Interlinking text documents with Linked Open Data enables the Web of Data to be used as background knowledge within document-oriented applications such as search and faceted browsing. As a step towards interconnecting the Web of Documents with the Web of Data, we developed DBpedia Spotlight, a syste ..."
Abstract
-
Cited by 174 (5 self)
- Add to MetaCart
(Show Context)
Interlinking text documents with Linked Open Data enables the Web of Data to be used as background knowledge within document-oriented applications such as search and faceted browsing. As a step towards interconnecting the Web of Documents with the Web of Data, we developed DBpedia Spotlight, a system for automatically annotating text documents with DBpedia URIs. DBpedia Spotlight allows users to configure the annotations to their specific needs through the DBpedia Ontology and quality measures such as prominence, topical pertinence, contextual ambiguity and disambiguation confidence. We compare our approach with the state of the art in disambiguation, and evaluate our results in light of three baselines and six publicly available annotation systems, demonstrating the competitiveness of our system. DBpedia Spotlight is shared as open source and deployed as a Web Service freely available for public use.
Executing SPARQL queries over the web of linked data
, 2009
"... Abstract. The Web of Linked Data forms a single, globally distributed dataspace. Due to the openness of this dataspace, it is not possible to know in advance all data sources that might be relevant for query answering. This openness poses a new challenge that is not addressed by traditional research ..."
Abstract
-
Cited by 104 (10 self)
- Add to MetaCart
(Show Context)
Abstract. The Web of Linked Data forms a single, globally distributed dataspace. Due to the openness of this dataspace, it is not possible to know in advance all data sources that might be relevant for query answering. This openness poses a new challenge that is not addressed by traditional research on federated query processing. In this paper we present an approach to execute SPARQL queries over the Web of Linked Data. The main idea of our approach is to discover data that might be relevant for answering a query during the query execution itself. This discovery is driven by following RDF links between data sources based on URIs in the query and in partial results. The URIs are resolved over the HTTP protocol into RDF data which is continuously added to the queried dataset. This paper describes concepts and algorithms to implement our approach using an iterator-based pipeline. We introduce a formalization of the pipelining approach and show that classical iterators may cause blocking due to the latency of HTTP requests. To avoid blocking, we propose an extension of the iterator paradigm. The evaluation of our approach shows its strengths as well as the still existing challenges. 1
Discovering and maintaining links on the web of data
- In The Semantic Web – ISWC 2009: 8th International Semantic Web Conference
, 2009
"... Abstract. The Web of Data is built upon two simple ideas: Employ the RDF data model to publish structured data on the Web and to create explicit data links between entities within different data sources. This pa-per presents the Silk – Linking Framework, a toolkit for discovering and maintaining dat ..."
Abstract
-
Cited by 88 (3 self)
- Add to MetaCart
(Show Context)
Abstract. The Web of Data is built upon two simple ideas: Employ the RDF data model to publish structured data on the Web and to create explicit data links between entities within different data sources. This pa-per presents the Silk – Linking Framework, a toolkit for discovering and maintaining data links between Web data sources. Silk consists of three components: 1. A link discovery engine, which computes links between data sources based on a declarative specification of the conditions that entities must fulfill in order to be interlinked; 2. A tool for evaluating the generated data links in order to fine-tune the linking specification; 3. A protocol for maintaining data links between continuously changing data sources. The protocol allows data sources to exchange both linksets as well as detailed change information and enables continuous link recom-putation. The interplay of all the components is demonstrated within a life science use case. Key words: Linked data, web of data, link discovery, link maintenance, record linkage, duplicate detection 1
A native and adaptive approach for unified processing of linked streams and linked data
, 2011
"... In this paper we address the problem of scalable, native and adaptive query processing over Linked Stream Data integrated with Linked Data. Linked Stream Data consists of data generated by stream sources, e.g., sensors, enriched with semantic descriptions, following the standards proposed for Linke ..."
Abstract
-
Cited by 63 (16 self)
- Add to MetaCart
(Show Context)
In this paper we address the problem of scalable, native and adaptive query processing over Linked Stream Data integrated with Linked Data. Linked Stream Data consists of data generated by stream sources, e.g., sensors, enriched with semantic descriptions, following the standards proposed for Linked Data. This enables the integration of stream data with Linked Data collections and facilitates a wide range of novel applications. Currently available systems use a “black box ” approach which delegates the processing to other engines such as stream/event processing engines and SPARQL query processors by translating to their provided languages. As the experimental results described in this paper show, the need for query translation and data transformation, as well as the lack of full control over the query execution, pose major drawbacks in terms of efficiency. To remedy these drawbacks, we present CQELS (Continuous Query Evaluation over Linked Streams), a native and adaptive query processor for unified query processing over Linked Stream Data and Linked Data. In contrast to the existing systems, CQELS uses a “white box” approach and implements the required query operators natively to avoid the overhead and limitations of closed system regimes. CQELS provides
A Reasonable Semantic Web
, 2010
"... The realization of Semantic Web reasoning is central to substantiating the Semantic Web vision. However, current mainstream research on this topic faces serious challenges, which forces us to question established lines of re-search and to rethink the underlying approaches. We argue that reasoning f ..."
Abstract
-
Cited by 51 (9 self)
- Add to MetaCart
The realization of Semantic Web reasoning is central to substantiating the Semantic Web vision. However, current mainstream research on this topic faces serious challenges, which forces us to question established lines of re-search and to rethink the underlying approaches. We argue that reasoning for the Semantic Web should be understood as "shared inference," which is not necessarily based on deductive methods. Model-theoretic semantics (and sound and complete reasoning based on it) functions as a gold standard, but applications dealing with large-scale and noisy data usu-ally cannot afford the required runtimes. Approximate methods, including deductive ones, but also approaches based on entirely different methods like machine learning or nature-inspired computing need to be investigated, while quality assurance needs to be done in terms of precision and recall val-
Searching and Browsing Linked Data with SWSE: the Semantic Web Search Engine
, 2011
"... 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 sea ..."
Abstract
-
Cited by 49 (15 self)
- Add to MetaCart
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 data – loosely 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.
Linked Data is Merely More Data
- IN: AAAI SPRING SYMPOSIUM ’LINKED DATA MEETS ARTIFICIAL INTELLIGENCE’, AAAI
, 2010
"... In this position paper, we argue that the Linked Open Data (LoD) Cloud, in its current form, is only of limited value for furthering the Semantic Web vision. Being merely a weakly linked “triple collection,” it will only be of very limited benefit for the AI or Semantic Web communities. We describe ..."
Abstract
-
Cited by 49 (18 self)
- Add to MetaCart
In this position paper, we argue that the Linked Open Data (LoD) Cloud, in its current form, is only of limited value for furthering the Semantic Web vision. Being merely a weakly linked “triple collection,” it will only be of very limited benefit for the AI or Semantic Web communities. We describe the corresponding problems with the LoD Cloud and give directions for research to remedy the situation.
LIMES -- A Time-Efficient Approach for Large-Scale Link Discovery on the Web of Data
, 2011
"... The Linked Data paradigm has evolved into a powerful enabler for the transition from the document-oriented Web into the Semantic Web. While the amount of data published as Linked Data grows steadily and has surpassed 25 billion triples, less than 5 % of these triples are links between knowledge base ..."
Abstract
-
Cited by 48 (8 self)
- Add to MetaCart
The Linked Data paradigm has evolved into a powerful enabler for the transition from the document-oriented Web into the Semantic Web. While the amount of data published as Linked Data grows steadily and has surpassed 25 billion triples, less than 5 % of these triples are links between knowledge bases. Link discovery frameworks provide the functionality necessary to discover missing links between knowledge bases in a semi-automatic fashion. Yet, the task of linking knowledge bases requires a significant amount of time, especially when it is carried out on large data sets. This paper presents and evaluates LIMES- a novel timeefficient approach for link discovery in metric spaces. Our approach utilizes the mathematical characteristics of metric spaces to compute estimates of the similarity between instances. These estimates are then used to filter out a large amount of those instance pairs that do not suffice the mapping conditions. Thus, LIMES can reduce the number of comparisons needed during the mapping process by several orders of magnitude. We present the mathematical foundation and the core algorithms employed in the implementation. We evaluate LIMES with synthetic data to elucidate its behavior on small and large data sets with different configurations and show that our approach can significantly reduce the time complexity of a mapping task. In addition, we compare the runtime of our framework with a state-ofthe-art link discovery tool. We show that LIMES is more than 60 times faster when mapping large knowledge bases.
Publishing and Consuming Provenance Metadata on the Web of Linked Data
- In: Proc. of 3rd Int. Provenance and Annotation Workshop
, 2010
"... Abstract. The World Wide Web evolves into a Web of Data, a huge, globally distributed dataspace that contains a rich body of machineprocessable information from a virtually unbound set of providers covering a wide range of topics. However, due to the openness of the Web little is known about who cre ..."
Abstract
-
Cited by 44 (4 self)
- Add to MetaCart
(Show Context)
Abstract. The World Wide Web evolves into a Web of Data, a huge, globally distributed dataspace that contains a rich body of machineprocessable information from a virtually unbound set of providers covering a wide range of topics. However, due to the openness of the Web little is known about who created the data and how. The fact that a large amount of the data on the Web is derived by replication, query processing, modification, or merging raises concerns of information quality. Poor quality data may propagate quickly and contaminate the Web of Data. Provenance information about who created and published the data and how, provides the means for quality assessment. This paper takes a first step towards creating a quality-aware Web of Data: we present approaches to integrate provenance information into the Web of Data and we illustrate how this information can be consumed. In particular, we introduce a vocabulary to describe provenance of Web data as metadata and we discuss possibilities to make such provenance metadata accessible as part of the Web of Data. Furthermore, we describe how this metadata can be queried and consumed to identify outdated information. 1
Using web data provenance for quality assessment
- In: Proc. of the Workshop on Semantic Web and Provenance Management at ISWC
, 2009
"... Abstract—The Web of Data cannot be a trustworthy data source unless an approach for evaluating the quality of data on the Web is established and integrated as part of the data publication and access process. In this paper, we propose an approach of using provenance information about the data on the ..."
Abstract
-
Cited by 43 (3 self)
- Add to MetaCart
(Show Context)
Abstract—The Web of Data cannot be a trustworthy data source unless an approach for evaluating the quality of data on the Web is established and integrated as part of the data publication and access process. In this paper, we propose an approach of using provenance information about the data on the Web to assess their quality and trustworthiness. Our contributions include a model for Web data provenance and an assessment method that can be adapted for specific quality criteria. We demonstrate how this method can be used to evaluate the timeliness of data on the Web, to reflect how up-to-date the data is. We also propose a possible solution to deal with missing provenance information by associating certainty values with calculated quality values. I.
