• Title/Summary/Keyword: Semantic class

검색결과 153건 처리시간 0.034초

Investigating Good Teaching and Learning Experiences in the Perspectives of University Students through Social Network Analysis

  • OH, Suna;LYU, Jeonghee;YUN, Heoncheol
    • Educational Technology International
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    • 제21권2호
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    • pp.193-216
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    • 2020
  • This study investigated university students' perspectives on good class and instructional practices through social network analysis. The subjects were 321 students in the third and fourth academic years in a Korean university. The subjects completed four open-ended questions, asking about experience of good class, good instructors' teaching practice, and their feelings and attitudes when participating in good class. As social network analysis, KrKwic (Korea Key Words in Context) was used to compute word frequencies and analyze semantic network structures and Ucinet Netdraw to assess centrality in the social network, consisting of degree centrality, closeness centrality, and between centrality. The results are as follows. First, students showed 5 keywords to depict what good class is, including 'understanding', 'example', 'video', 'interest', and 'communication'. Second, the characteristics of teaching methods by professors who practice good class indicate 'assignments', 'questions', 'understanding', 'example', and 'feedback'. Third, the top 5 keywords of students' attitudes as participating in good class are 'active', 'participation', 'focus', 'listening', and 'asking'. Last, keywords depicting desirable class that students most wanted to take next time are 'assignments', 'rewards', 'understanding', 'difficulty', and 'interest'. The findings from this study include the meanings of the semantic network structures of words in the text making up messages. Also this study can provide empirical evidence for educators and educational practitioners in higher education to create effective learning environments.

DA-Res2Net: a novel Densely connected residual Attention network for image semantic segmentation

  • Zhao, Xiaopin;Liu, Weibin;Xing, Weiwei;Wei, Xiang
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제14권11호
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    • pp.4426-4442
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    • 2020
  • Since scene segmentation is becoming a hot topic in the field of autonomous driving and medical image analysis, researchers are actively trying new methods to improve segmentation accuracy. At present, the main issues in image semantic segmentation are intra-class inconsistency and inter-class indistinction. From our analysis, the lack of global information as well as macroscopic discrimination on the object are the two main reasons. In this paper, we propose a Densely connected residual Attention network (DA-Res2Net) which consists of a dense residual network and channel attention guidance module to deal with these problems and improve the accuracy of image segmentation. Specifically, in order to make the extracted features equipped with stronger multi-scale characteristics, a densely connected residual network is proposed as a feature extractor. Furthermore, to improve the representativeness of each channel feature, we design a Channel-Attention-Guide module to make the model focusing on the high-level semantic features and low-level location features simultaneously. Experimental results show that the method achieves significant performance on various datasets. Compared to other state-of-the-art methods, the proposed method reaches the mean IOU accuracy of 83.2% on PASCAL VOC 2012 and 79.7% on Cityscapes dataset, respectively.

Support Vector Machine Learning for Region-Based Image Retrieval with Relevance Feedback

  • Kim, Deok-Hwan;Song, Jae-Won;Lee, Ju-Hong;Choi, Bum-Ghi
    • ETRI Journal
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    • 제29권5호
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    • pp.700-702
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    • 2007
  • We present a relevance feedback approach based on multi-class support vector machine (SVM) learning and cluster-merging which can significantly improve the retrieval performance in region-based image retrieval. Semantically relevant images may exhibit various visual characteristics and may be scattered in several classes in the feature space due to the semantic gap between low-level features and high-level semantics in the user's mind. To find the semantic classes through relevance feedback, the proposed method reduces the burden of completely re-clustering the classes at iterations and classifies multiple classes. Experimental results show that the proposed method is more effective and efficient than the two-class SVM and multi-class relevance feedback methods.

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분류된 영역 병합에 의한 객체 원형을 보존하는 영상 분할 (Image segmentation preserving semantic object contours by classified region merging)

  • 박현상;나종범
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 1998년도 하계종합학술대회논문집
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    • pp.661-664
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    • 1998
  • Since the region segmentation at high resolution contains most of viable semantic object contours in an image, the bottom-up approach for image segmentation is appropriate for the application such as MPEG-4 which needs to preserve semantic object contours. However, the conventioal region merging methods, that follow the region segmentation, have poor performance in keeping low-contrast semantic object contours. In this paper, we propose an image segmentation algorithm based on classified region merging. The algorithm pre-segments an image with a large number of small regions, and also classifies it into several classes having similar gradient characteristics. Then regions only in the same class are merged according to the boundary weakness or statisticsal similarity. The simulation result shows that the proposed image segmentation preserves semantic object contours very well even with a small number of regions.

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Towards a Ubiquitous Robotic Companion: Design and Implementation of Ubiquitous Robotic Service Framework

  • Ha, Young-Guk;Sohn, Joo-Chan;Cho, Young-Jo;Yoon, Hyun-Soo
    • ETRI Journal
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    • 제27권6호
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    • pp.666-676
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    • 2005
  • In recent years, motivated by the emergence of ubiquitous computing technologies, a new class of networked robots, ubiquitous robots, has been introduced. The Ubiquitous Robotic Companion (URC) is our conceptual vision of ubiquitous service robots that provide users with the services they need, anytime and anywhere in ubiquitous computing environments. To realize the vision of URC, one of the essential requirements for robotic systems is to support ubiquity of services: that is, a robot service must be always available even though there are changes in the service environments. Specifically robotic systems need to be automatically interoperable with sensors and devices in current service environments, rather than statically preprogrammed for them. In this paper, the design and implementation of a semantic-based ubiquitous robotic space (SemanticURS) is presented. SemanticURS enables automated integration of networked robots into ubiquitous computing environments exploiting Semantic Web Services and AI-based planning technologies.

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온톨로지 기반 대학정보 검색 시스템의 설계 및 구현 (Implementation and Design of College Information Retrieval System Based On Ontology)

  • 박종훈;김철원
    • 한국정보통신학회논문지
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    • 제16권2호
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    • pp.296-301
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    • 2012
  • 오늘날 효과적인 정보검색을 위해 지능형 검색에 대한 다양한 기법들을 사용하고 있다. 이중에서 효과적인 검색 방법은 온톨로지 기술을 적용하는 것이다. 온톨로지는 시맨틱웹에서의 핵심기술이라 할 수 있다. 시맨틱웹에서 온톨로지 기술은 간단하면서 정확하게 추론엔진을 통하여 관련 정보를 검색하는데 사용될 수 있다. 본 논문에서는 대학, 대학원, 구성원을 중심으로 정보를 검색할 수 있는 온톨로지 기반 대학정보검색 시스템을 설계 및 구현을 하고자 한다. 대학, 대학원, 구성원 정보들의 계층구조를 수집하였으며, 온톨로지 개발도구인 protege 에디터를 이용하였다. 대학정보를 온톨로지로 설계하기 위해 설계된 대학정보 온톨로지를 protege 에디터의 추론기능을 이용하여 검증하였으며, 검증된 온톨로지는 지나 추론엔진을 적용하여 웹서비스 할 수 있도록 대학정보검색 시스템을 구현하였다.

시맨틱 브로커 기반 시맨틱 서비스 조합 (Semantic Service Composition Based on Semantic Broker)

  • 정한민;이미경;류범종
    • 한국콘텐츠학회:학술대회논문집
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    • 한국콘텐츠학회 2009년도 춘계 종합학술대회 논문집
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    • pp.283-288
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    • 2009
  • 시맨틱 서비스는 온톨로지 기반으로 검색 API 또는 추론 API를 제공하는 서비스로 정의할 수 있는데, 웹 서비스 등의 대화 방식을 이용하며 웹상에서 공개된다. 온톨로지 기반이므로 URI (Uniform Resource Identifier)를 지원하며 온톨로지 스키마에 정의된 클래스와 속성 (Property)을 사용하여 미리 정의된 작업을 수행한다. 시맨틱 서비스는 입력 인자가 온톨로지에 정의된 클래스들로 구성되므로 시맨틱 서비스 조합 시에 온톨로지를 반드시 참조할 필요가 있다. 본 연구는 사용자 제시 조건을 입력받아 시맨틱 브로커를 이용하여 시맨틱 서비스 관리 서버에 등록된 시맨틱 서비스들 내의 온톨로지 정보와 관리 정보를 참조하여 조건에 맞는 시맨틱 서비스를 조합하는 방법을 제시한다. 사용자 제시 조건으로는 입력 인스턴스, 출력 클래스, 시각화 유형 (Visualization Type), 시맨틱 서비스명, 속성명 등이 있다. 시맨틱 서비스 조합은 사용자 제시 조건을 기반으로 동적으로 이루어지며, 그 결과는 복합 시맨틱 서비스를 포함하는 시맨틱 서비스 파이프라인들로서 사용자에게 순위화되어 제시된다. 사용자는 시맨틱 브로커에 의해 제시된 시맨틱 서비스 파이프라인들을 실행해 봄으로써 원하는 시맨틱 서비스 조합을 찾을 수 있다. 결국, 본 연구를 통해 개발된 도구는 다양한 곳에서 개발된 시맨틱 서비스들을 동적으로 연계하여 새로운 시맨틱 서비스를 개발하고자 하는 서비스 기획자를 지원하데 도움을 준다.

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

  • 노상규;박현정;박진수
    • Asia pacific journal of information systems
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    • 제17권4호
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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.

한국어 의미 표지 부착 말뭉치 구축을 위한 자동 술어-논항 분석기 개발 (A Development of the Automatic Predicate-Argument Analyzer for Construction of Semantically Tagged Korean Corpus)

  • 조정현;정현기;김유섭
    • 정보처리학회논문지B
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    • 제19B권1호
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    • pp.43-52
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    • 2012
  • 의미 역 결정 (Semantic Role Labeling)은 문장의 각 요소들의 의미 관계를 파악하는 연구 분야로써 어휘 중의성 해소와 더불어 자연언어처리에서의 의미 분석에서 매우 중요한 위치를 차지하고 있다. 그러나 한국어의 경우에는 의미 역 결정에 필요한 언어 자원이 구축되지 못하여 연구의 진행이 매우 미진한 상황이다. 본 논문에서는 의미 역 결정에 필요한 언어 자원 중에서 가장 널리 사용되고 있는 PropBank의 한국어 버전의 구축을 위한 시작 단계로써 자동 술어-논항 분석기를 개발하였다. 자동 술어-논항 분석기는 크게 의미 어휘 사전과 자동 술어-논항 추출기로 구성된다. 의미 어휘 사전은 한국어 동사의 격틀 정보를 구축한 사전이며 자동 술어-논항 추출기는 구문 표지 부착된 말뭉치로부터 특정 술어와 관련있는 논항의 의미 부류를 결정하는 모듈이다. 본 논문에서 개발된 자동 술어-논항 분석기는 향후 한국어 PropBank의 구축을 용이하게 할 것이며, 궁극적으로는 한국어 의미 역 결정에 큰 역할을 할 것이다.

언어 네트워크 분석을 활용한 중학생들의 과학 교사에 대한 수업 상황별 선호, 기피 이미지 분석 (Analysis of Images of Middle School Students' Preference and Avoidance of Science Teachers by Class Situation Using Semantic Network Analysis)

  • 조윤정;김영신;임수민
    • 과학교육연구지
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    • 제45권1호
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    • pp.55-68
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    • 2021
  • 현대 사회는 빠르게 변화되고 있으며, 이에 따라 요구되는 교사상도 변하고 있다. 중학생은 신체적, 정신적으로 큰 변화를 겪는 미성숙한 시기로 교사의 영향력이 매우 크다. 학생들이 교사를 어떻게 인지하는가는 교사와 학생 간의 관계를 좌우한다. 이에 학생이 교사에게 바라는 것이 무엇인지를 파악할 필요가 있다. 본 연구의 목적은 중학생이 인지하는 수업 상황별 선호, 기피하는 과학 교사 이미지에 대해 분석하고자 하는 것이다. 이를 위하여 중학생 502명을 대상으로 수업 상황을 수업 형태, 수업 자료 제시 방법, 교과 지도 방법, 교과 내용 설명 방식, 수업 분위기 조성의 5가지로 나누어 선호, 기피하는 과학 교사의 이미지를 개방형으로 기술하도록 하였다. 중학생들에 의해 제시된 개념들은 언어 네트워크 분석법을 통해 분석하였다. 본 연구의 결론은 다음과 같다. 첫째, 중학생들이 과학에 흥미를 느끼게 하기 위해서는 탐구 중심의 실험 수업이 이루어져야 한다. 둘째, 과학 교사에 의한 수업의 변화가 선호하는 과학 수업으로 변화시킬 수 있다. 셋째, 학생이 이해할 수 있도록 수준에 맞는 학생 중심의 수업이 이루어져야 한다. 마지막으로 과학 교사와 학생, 학생과 학생 사이의 소통을 통해 과학 교사는 지속적으로 노력하며, 이를 통한 과학 수업의 변화가 있길 기대한다.