• 한국지능정보시스템학회:학술대회논문집
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• 한국지능정보시스템학회 2001년도 The Pacific Aisan Confrence On Intelligent Systems 2001
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• pp.441-447
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• 2001

The problem of query rewriting using views has interested in the context of data integration where source data is described by the views on global relations. When the query and views are of the form of conjunctive queries, the rewriting is a union of conjunctive queries each of which is contained in the original query and consists of only views. Most previous methods for query rewriting using views are 2-step algorithms. In the first step, they identify the views that are useful in rewriting and in the second step they construct all correct rewritings by combining the views that gained in the first step. The larger the number of selected views in the first step, the larger the number of candidate rewritings in the second step. We want to minimize the number of selected views in the first step by defining stringent conditions for a view to be participated in rewritings. In this paper, first we offer a necessary condition for the existence of a rewriting that includes a view. For the common case that predicate repetitions are not allowed in the bodies of views, we show that our algorithm for testing the condition is done in a polynomial-time. Second, we offer an algorithm to construct contained rewritings using the view instances that are computed in the first step. The exponential containment-mapping test in the second step is not needed in our algorithm.

• 한국정보통신학회논문지
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• 제6권8호
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• pp.1336-1345
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• 2002

데이터웨어하우스에서 실체뷰는 사용자의 정보처리 요구에 신속하게 응답하기 위한 주요한 수단이다. 데이터웨어하우스내에 실체뷰의 개수가 많을수록 사용자의 질의요구를 실체뷰내에서 처리할 수 있는 확률이 높아지므로 신속한 응답이 가능하다. 데이터웨어하우스내에 유지할 수 있는 실체뷰의 개수에 대한 주요 제약은 기본릴레이션의 변화에 기인하는 실체뷰 갱신시간이다. 본 논문에서는 MIN/MAX 함수를 포함하는 실체뷰에 대해서 기본릴레이션의 MIN/MAX값의 변화가 빈번할 경우에도 실체뷰 갱신시간을 절약할 수 있는 효율적인 실체뷰 갱신정책을 제안한다. 기본릴레이션의 MIN/MAX값의 변경을 삽입/삭제연산으로 구분하여 실체뷰를 갱신하면 실체뷰의 MIN/MAX값 갱신을 위하여 기본릴레이션에 접근해야 할 횟수가 줄어든다.

• Asia pacific journal of information systems
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• 제13권4호
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• pp.191-206
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• 2003

More views in data warehouse, can respond to the users more rapidly because the user's requests might be processed by accessing only the materialized views with higher probabilities rather than accessing base relations. But, the update duration for maintaining materialized views limits the number of materialized views in data warehouse. In this paper, we propose the algorithm for reducing update duration of materialized views, of which aggregation functions are maintained by self-maintenance. We also implement the proposed algorithm and evaluate the performance of the algorithm.

• 산업공학
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• 제16권2호
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• pp.229-239
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• 2003

The On-Line Analytical Processing (OLAP) tools access data from the data warehouse for complex data analysis, such as multidimensional data analysis, and decision support activities. Current research has lead to new developments in all aspects of data warehousing, however, there are still a number of problems that need to be solved for making data warehousing effective. View maintenance, one of them, is to maintain view in response to updates in source data. Keeping the view consistent with updates to the base relations, however, can be expensive, since it may involve querying external sources where the base relations reside. In order to reduce maintenance costs, it is possible to maintain the views using information that is strictly local to the data warehouse. This process is usually referred to as "self-maintenance of views". A number of algorithm have been proposed for self maintenance of views where they keep some additional information in data warehouse in the form of auxiliary views. But those algorithms did not consider a consistency of materialized views using view self-maintenance. The purpose of this paper is to research consistency problem when self-maintenance of views is implemented. The proposed "conveyor algorithm" will resolved a complete consistency of materialized view using self-maintenance with considering network delay. The rationale for conveyor algorithm and performance characteristics are described in detail.

• 한국엔터테인먼트산업학회논문지
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• 제14권8호
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• pp.63-75
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• 2020

이 연구는 유튜브 케이팝 뮤직 비디오의 조회수와 시각적 연출 특성 간의 관계에 대해서 연구한다. 2012년 '강남스타일'의 국제적인 주목을 시작으로 현재까지 전 세계로부터 관심받고 있는 케이팝 뮤직 비디오를 중심으로 분석한다. 직관적으로 드러나지 않는 뮤직 비디오 조회수에 관련한 요소의 실재 여부와 조회수에 영향을 주는 구체적인 요소의 발견 가능성에 대해 의문을 제기한다. 이전 연구는 조회수와 관련된 뮤직 비디오의 요소를 알아내는 데에 있어서 소수의 작품을 중심으로 뮤직 비디오들을 비교하는 연구방법을 선택했기 때문에 중심이 되는 작품에 편향된 결과가 나온다는 한계가 있었다. 따라서, 이 연구는 조회수에 따라 9개의 뮤직 비디오를 3개의 그룹으로 나누고 시각적 연출 특성을 기준으로 분석하여 3개의 그룹 간 차이점 및 각 그룹의 특징을 찾는 것을 목표로 한다. 이 연구는 조회수라는 요소가 주목받고 있는 유튜브 시장 내 뮤직 비디오 분야의 발전에 기여할 것으로 기대된다.

• 패션비즈니스
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• 제24권1호
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• pp.75-87
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• 2020

The purpose of this study is to find trends in new media fashion content by analyzing the fashion content of the official Instagram accounts of domestic fashion magazines that are being transformed by digital media. The framework for these analysis of fashion content type and methods of production is based on one used in an earlier research project. Empirical analysis is conducted on Vogue Korea's official Instagram accounts, using the highest number of major views as the secondary measure of interest. After screening for fashion content in posts on the Vogue Korea account for four months, 291 short video postings were extracted to analyze the number of views the postings received. The results were categorized as 'star', 'show/exhibition', 'product', 'shop', 'fashion film', 'designer', or 'event', included in the data are the number of postings by type and the number of views by post. Based on the characteristics of the creator and the editing, the posts were classified into 'professional production highlight', 'professional production private', 'UCC' or 'GIF' videos, the number of views per post were also collected. The research results show different levels of interest depending on the type of fashion content, and also on the way the videos were produced. The study also investigated how the combination of these two factors affects interest. When producing a new media fashion content, combining a 'star' type post with 'professional production private' video content was most popular. The selection of production method is therefore important even given the same type of content.

• ETRI Journal
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• 제38권6호
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• pp.1114-1123
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• 2016

Multi-view video plus depth (MVD) has been widely used owing to its effectiveness in three-dimensional data representation. Using MVD, color videos with only a limited number of real viewpoints are compressed and transmitted along with captured or estimated depth videos. Because the synthesized views are generated from decoded real views, their original reference views do not exist at either the transmitter or receiver. Therefore, it is challenging to define an efficient metric to evaluate the quality of synthesized images. We propose a novel metric-the reduced-reference quality metric. First, the effects of depth distortion on the quality of synthesized images are analyzed. We then employ the high correlation between the local depth distortions and local color characteristics of the decoded depth and color images, respectively, to achieve an efficient depth quality metric for each real view. Finally, the objective quality metric of the synthesized views is obtained by combining all the depth quality metrics obtained from the decoded real views. The experimental results show that the proposed quality metric correlates very well with full reference image and video quality metrics.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.276-276
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• 2000

This paper presents the efficient algorithms for the pose determination of a circular object with and without a priori knowledge of the object radius. The developed algorithms valid for a circular object are the result of the elaboration of Ma's work [2], which determines the pose of a conic object from two perspective views. First, the geometric constraint of a circular object and its projection on the image plane of a camera is described. The number of perspective views required for the object pose determination with and without a priori knowledge of the object radius is also discussed. Second, with a priori knowledge of the object radius, the pose of a circular object is determined from a single perspective view. The object pose information, expressed by two surface normal vectors and one position vector, is given in a closed form and with no ambiguity. Third, without a priori knowledge of the object radius, the pose of a circular object is determined from two perspective views. While the surface normal vectors are obtained from the first view, the position vector is obtained from the two views.

• International Journal of Computer Science & Network Security
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• 제22권2호
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• pp.304-310
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• 2022

This research examines the views of teachers and parents of special schools in Saudi Arabia, exploring the schools' strengths and disadvantages, as well as their impact on teachers, parents, and students with disabilities. The respondents' key views of the schools are identified, including the areas of consensus and conflict, and recommendations are made for the future, based on the findings. This research concerns a specific special education school in Saudi Arabia, and focuses on the understanding of special education in the country. The approach to the study is targeted and qualitative, with the six participants, three teachers and three parents, intentionally selected. The data collection is conducted via semi-structured interviews that explore the participants' views of special education in Saudi Arabia. A number of issues emerge from the results, and one raised by all three teachers is the need to improve school facilities. Although all three parents report that their children clearly benefited from attending a special school, two felt that the offering was insufficient, in terms of the teaching methods, and of supporting cognitive skills.

• 한국통신학회논문지
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• 제38C권10호
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• pp.903-910
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• 2013

무안경방식 스테레오스코픽 3D 디스플레이 시스템은 수평, 깊이방향에 대한 관찰자유도가 안경방식에 비해 매우 좁다. 본 논문에서는 분할된 3중의 기울어진 시차장벽(TS-SPB)을 사용하여 무안경방식에서 수평방향의 시점수를 유지하면서도 깊이방향의 시역폭을 증가시키는 혁신적인 방법을 제안한다. 본 논의의 당위성은 실제와 유사한 환경에서의 전산모사를 통하여 검증되었다. 결과적으로 색분산이 없는 수평방향의 가용 최대 시점수는 $2^n$이며, 깊이방향의 시역폭은 단일 시차장벽(SPB)의 경우와 비교하여 3.36배 증가하였다.