• Title/Summary/Keyword: RDF Knowledge Base

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A Global-Interdependence Pairwise Approach to Entity Linking Using RDF Knowledge Graph (개체 링킹을 위한 RDF 지식그래프 기반의 포괄적 상호의존성 짝 연결 접근법)

  • Shim, Yongsun;Yang, Sungkwon;Kim, Hong-Gee
    • KIPS Transactions on Software and Data Engineering
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    • v.8 no.3
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    • pp.129-136
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    • 2019
  • There are a variety of entities in natural language such as people, organizations, places, and products. These entities can have many various meanings. The ambiguity of entity is a very challenging task in the field of natural language processing. Entity Linking(EL) is the task of linking the entity in the text to the appropriate entity in the knowledge base. Pairwise based approach, which is a representative method for solving the EL, is a method of solving the EL by using the association between two entities in a sentence. This method considers only the interdependence between entities appearing in the same sentence, and thus has a limitation of global interdependence. In this paper, we developed an Entity2vec model that uses Word2vec based on knowledge base of RDF type in order to solve the EL. And we applied the algorithms using the generated model and ranked each entity. In this paper, to overcome the limitations of a pairwise approach, we devised a pairwise approach based on comprehensive interdependency and compared it.

Design of Mapping Structure and Implementation to transform Object-Oriented Thesaurus into RDF Schema (객체지향 시소러스를 RDF Schema로 변환하기 위한 매핑 구조의 설계 및 구현)

  • 양경아;방선이;양재동
    • Proceedings of the Korean Information Science Society Conference
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    • 2002.10d
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    • pp.289-291
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    • 2002
  • 본 논문에서는 객체지향 패러다임의 구조적 특성을 적용하여 만든 시소러스를 이용하여 웹 자원의 의미적 연관성을 RDF 형식으로 표현할 수 있는 RDF 문서 자동 생성기를 소개한다. 객체지향 시소러스를 RDF 형식으로 나타내기 위해 시소러스에 사용된 객체와 관계의 내용을 명세한 네임 스페이스를 정의하여 시맨틱 웹에서 메타데이타를 기술하는 표준이 되는 RDF와 RDF Schema 형식으로 매핑할 수 있다. 이러한 연구를 통해 객체지향 시소러스의 내용을 RDF 형식으로 표현함으로써 지식베이스(KnowledgeBase)라 불리는 온톨로지를 생성할 수 있으며, 구축된 온톨로지는 시맨틱 웹 상의 에이전트나 다른 어플리케이션에 응용될 수 있다.

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RDF 지식 베이스의 자원 중요도 계산 알고리즘에 대한 연구

  • No, Sang-Gyu;Park, Hyeon-Jeong;Park, Jin-Su
    • Proceedings of the Korea Inteligent Information System Society Conference
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    • 2007.05a
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    • pp.123-137
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    • 2007
  • The information space of semantic web comprised of various resources, properties, and relationships is more complex than that of WWW comprised of just documents and hyperlinks. Therefore, ranking methods in the semantic web should be modified to reflect the complexity of the information space. In this paper we propose a method of ranking query results from RDF(Resource Description Framework) knowledge bases. The ranking criterion is the importance of a resource computed based on the link structure of the RDF graph. Our method is expected to solve a few problems in the prior research including the Tightly-Knit Community Effect. We illustrate our methods using examples and discuss directions for future research.

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Efficient Change Detection between RDF Models Using Backward Chaining Strategy (후방향 전진 추론을 이용한 RDF 모델의 효율적인 변경 탐지)

  • Im, Dong-Hyuk;Kim, Hyoung-Joo
    • Journal of KIISE:Computing Practices and Letters
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    • v.15 no.2
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    • pp.125-133
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    • 2009
  • RDF is widely used as the ontology language for representing metadata on the semantic web. Since ontology models the real-world, ontology changes overtime. Thus, it is very important to detect and analyze changes in knowledge base system. Earlier studies on detecting changes between RDF models focused on the structural differences. Some techniques which reduce the size of the delta by considering the RDFS entailment rules have been introduced. However, inferencing with RDF models increases data size and upload time. In this paper, we propose a new change detection using RDF reasoning that only computes a small part of the implied triples using backward chaining strategy. We show that our approach efficiently detects changes through experiments with real-life RDF datasets.

A Study of Dynamic Web Ontology for Comparison-shopping Agent based on Semantic Web (시멘틱 웹 기반의 비교구매 에이전트를 위한 동적 웹 온톨로지에 대한 연구)

  • Kim, Su-Kyoung;Ahn, Ki-Hong
    • Journal of Intelligence and Information Systems
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    • v.11 no.2
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    • pp.31-45
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    • 2005
  • In this paper, convert in RDF triple and a RDF document through RDF document converters and design metadata schema about a digital camcorder after use Wrapper technology, and acquiring commodity information of a HTML page about the digital camcorder which these papers are defined so as to be different by electronic commerce stores, and is expressed. Save in digital camcorder domain ontology storage that implemented to relational database to DCC knowledge base ontology as convert to OWL Web ontology based on designed metadata schema. Through compare with rdf and DCCKBO, mapping, and inference process, provide to buyers by DCC information of the store that had the commodity purchasing information which is the best, and proposed a dynamic Web ontology guessed to contents of the best commodity purchasing information, and to define domain ontology saved in DCCKBO.

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Efficient Ontology Object Model for Semantic Web (시맨틱웹을 위한 효율적인 온톨로지 객체 모델)

  • Yun Bo-Hyun;Seo Chang-Ho
    • Journal of the Korea Society of Computer and Information
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    • v.11 no.2 s.40
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    • pp.7-13
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    • 2006
  • The advent of Semantic Web has generated several methods that can access the data on the web. Thus, it is necessary to handle the data by accessing the current web ontology as well as the existing knowledge base system. Web ontology languages are RDF(Resource Description Framework), DAML-OIL, OWL(Web Ontology Language), and so on. This paper presents the creation and the method of the ontology object model that can access, represent, and process the web ontology and the existing knowledge base. Unlike the existing access approach of web ontology using the model on memory constructed by each parser, we divide the model of web ontology into three layers such as frame-based ontology layer, generic ontology layer, and functional ontology layer. Generic ontology layer represents the common vocabulary among several domains and functional ontology layer contains the dependent vocabulary to each ontology respectively. Our model gets rid of the redundancy of the representation and enhances the reusability. Moreover, it can provide the easy representation of knowledge and the fast access of the model in the application.

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Comparison Between OWL and Topic Maps Using Ontology Development Tool (온톨로지 저작도구를 이용한 OWL과 토픽맵의 비교)

  • Park Soo-Min;Kim Hoon-Min;Yang Jung-Jin
    • Proceedings of the Korean Information Science Society Conference
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    • 2006.06b
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    • pp.211-213
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    • 2006
  • 시맨틱 웹과 에이전트 시스템을 위한 지식 기반(Knowledge Base)을 구축하기 위해 W3C의 RDF와 ISO의 토픽맵(Topic Maps)이 사용되고 있다. 이 두 표준은 표현력 상에서 중복되는 부분이 많음에도 불구하고 서로 다른 방면을 추구하였지만, 최근 W3C에서는 Task Force 팀을 구성하여 둘 사이의 상호운용성을 확보하려는 시도를 보이고 있다. 이에 따라 단순히 자원에 대한 메타 데이터를 구축하는 RDF에 semantic을 부여하는 RDF Vocabulary인 OWL과 토픽맵 간의 상호운용도 관심을 받기 시작하였다. 본 논문에서는 이러한 OWL과 토픽맵의 상호운용 가능성을 확인하기 위해 두 표준을 지원하는 각 저작 도구를 활용하여 표현력과 기능적 비교를 수행하고 이를 통하여 둘 사이에 어떠한 차이점이 있는가와 기능적인 극복을 위한 대안을 제시한다.

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A Study on Developing an Adaptive R&D Information Service Portal (연구 활동 지원을 위한 적응형 연구정보 지원 포털 구축에 관한 연구)

  • Choi, Sung-Pil;Cho, Hyun-Yang
    • Journal of the Korean Society for Library and Information Science
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    • v.41 no.4
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    • pp.229-250
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    • 2007
  • This paper suggested a way to solve the problems by using domain experts who are already in the significant level of knowledge in those fields. For the purpose of achieving our goal, a very simple and efficient approach to construct the knowledge-base which can play an important role in providing researchers with essential information in need was proposed. In addition, the Adaptive R&D Information Service Portal with a new schema structure and a construction method of representing expert's knowledge efficiently was developed. With the simplicity and expandability of the proposed system it can be a good model for a similar system to be developed.

SSQUSAR : A Large-Scale Qualitative Spatial Reasoner Using Apache Spark SQL (SSQUSAR : Apache Spark SQL을 이용한 대용량 정성 공간 추론기)

  • Kim, Jonghoon;Kim, Incheol
    • KIPS Transactions on Software and Data Engineering
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    • v.6 no.2
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    • pp.103-116
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    • 2017
  • In this paper, we present the design and implementation of a large-scale qualitative spatial reasoner, which can derive new qualitative spatial knowledge representing both topological and directional relationships between two arbitrary spatial objects in efficient way using Aparch Spark SQL. Apache Spark SQL is well known as a distributed parallel programming environment which provides both efficient join operations and query processing functions over a variety of data in Hadoop cluster computer systems. In our spatial reasoner, the overall reasoning process is divided into 6 jobs such as knowledge encoding, inverse reasoning, equal reasoning, transitive reasoning, relation refining, knowledge decoding, and then the execution order over the reasoning jobs is determined in consideration of both logical causal relationships and computational efficiency. The knowledge encoding job reduces the size of knowledge base to reason over by transforming the input knowledge of XML/RDF form into one of more precise form. Repeat of the transitive reasoning job and the relation refining job usually consumes most of computational time and storage for the overall reasoning process. In order to improve the jobs, our reasoner finds out the minimal disjunctive relations for qualitative spatial reasoning, and then, based upon them, it not only reduces the composition table to be used for the transitive reasoning job, but also optimizes the relation refining job. Through experiments using a large-scale benchmarking spatial knowledge base, the proposed reasoner showed high performance and scalability.

A Ranking Algorithm for Semantic Web Resources: A Class-oriented Approach (시맨틱 웹 자원의 랭킹을 위한 알고리즘: 클래스중심 접근방법)

  • Rho, Sang-Kyu;Park, Hyun-Jung;Park, Jin-Soo
    • Asia pacific journal of information systems
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    • v.17 no.4
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    • pp.31-59
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    • 2007
  • We frequently use search engines to find relevant information in the Web but still end up with too much information. In order to solve this problem of information overload, ranking algorithms have been applied to various domains. As more information will be available in the future, effectively and efficiently ranking search results will become more critical. In this paper, we propose a ranking algorithm for the Semantic Web resources, specifically RDF resources. Traditionally, the importance of a particular Web page is estimated based on the number of key words found in the page, which is subject to manipulation. In contrast, link analysis methods such as Google's PageRank capitalize on the information which is inherent in the link structure of the Web graph. PageRank considers a certain page highly important if it is referred to by many other pages. The degree of the importance also increases if the importance of the referring pages is high. Kleinberg's algorithm is another link-structure based ranking algorithm for Web pages. Unlike PageRank, Kleinberg's algorithm utilizes two kinds of scores: the authority score and the hub score. If a page has a high authority score, it is an authority on a given topic and many pages refer to it. A page with a high hub score links to many authoritative pages. As mentioned above, the link-structure based ranking method has been playing an essential role in World Wide Web(WWW), and nowadays, many people recognize the effectiveness and efficiency of it. On the other hand, as Resource Description Framework(RDF) data model forms the foundation of the Semantic Web, any information in the Semantic Web can be expressed with RDF graph, making the ranking algorithm for RDF knowledge bases greatly important. The RDF graph consists of nodes and directional links similar to the Web graph. As a result, the link-structure based ranking method seems to be highly applicable to ranking the Semantic Web resources. However, the information space of the Semantic Web is more complex than that of WWW. For instance, WWW can be considered as one huge class, i.e., a collection of Web pages, which has only a recursive property, i.e., a 'refers to' property corresponding to the hyperlinks. However, the Semantic Web encompasses various kinds of classes and properties, and consequently, ranking methods used in WWW should be modified to reflect the complexity of the information space in the Semantic Web. Previous research addressed the ranking problem of query results retrieved from RDF knowledge bases. Mukherjea and Bamba modified Kleinberg's algorithm in order to apply their algorithm to rank the Semantic Web resources. They defined the objectivity score and the subjectivity score of a resource, which correspond to the authority score and the hub score of Kleinberg's, respectively. They concentrated on the diversity of properties and introduced property weights to control the influence of a resource on another resource depending on the characteristic of the property linking the two resources. A node with a high objectivity score becomes the object of many RDF triples, and a node with a high subjectivity score becomes the subject of many RDF triples. They developed several kinds of Semantic Web systems in order to validate their technique and showed some experimental results verifying the applicability of their method to the Semantic Web. Despite their efforts, however, there remained some limitations which they reported in their paper. First, their algorithm is useful only when a Semantic Web system represents most of the knowledge pertaining to a certain domain. In other words, the ratio of links to nodes should be high, or overall resources should be described in detail, to a certain degree for their algorithm to properly work. Second, a Tightly-Knit Community(TKC) effect, the phenomenon that pages which are less important but yet densely connected have higher scores than the ones that are more important but sparsely connected, remains as problematic. Third, a resource may have a high score, not because it is actually important, but simply because it is very common and as a consequence it has many links pointing to it. In this paper, we examine such ranking problems from a novel perspective and propose a new algorithm which can solve the problems under the previous studies. Our proposed method is based on a class-oriented approach. In contrast to the predicate-oriented approach entertained by the previous research, a user, under our approach, determines the weights of a property by comparing its relative significance to the other properties when evaluating the importance of resources in a specific class. This approach stems from the idea that most queries are supposed to find resources belonging to the same class in the Semantic Web, which consists of many heterogeneous classes in RDF Schema. This approach closely reflects the way that people, in the real world, evaluate something, and will turn out to be superior to the predicate-oriented approach for the Semantic Web. Our proposed algorithm can resolve the TKC(Tightly Knit Community) effect, and further can shed lights on other limitations posed by the previous research. In addition, we propose two ways to incorporate data-type properties which have not been employed even in the case when they have some significance on the resource importance. We designed an experiment to show the effectiveness of our proposed algorithm and the validity of ranking results, which was not tried ever in previous research. We also conducted a comprehensive mathematical analysis, which was overlooked in previous research. The mathematical analysis enabled us to simplify the calculation procedure. Finally, we summarize our experimental results and discuss further research issues.