• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권6호
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• pp.2730-2747
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• 2016

Due to the limitation of the bandwidth resource and capture resolution of depth cameras, low resolution depth maps should be up-sampled to high resolution so that they can correspond to their texture images. In this paper, a novel depth map up-sampling algorithm is proposed by exploiting the fractal internal self-referential feature. Fractal parameters which are extracted from a depth map, describe the internal self-referential feature of the depth map, do not introduce inherent scale and just retain the relational information of the depth map, i.e., fractal transforms provide a resolution-independent description for depth maps and could up-sample depth maps to an arbitrary high resolution. Then, an enhancement method is also proposed to further improve the performance of the up-sampled depth map. The experimental results demonstrate that better quality of synthesized views is achieved both on objective and subjective performance. Most important of all, arbitrary resolution depth maps can be obtained with the aid of the proposed scheme.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2005년도 Proceedings of ISRS 2005
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• pp.763-765
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• 2005

In the area of remote sensing, an immense number of images are continuously generated by various remote sensing systems. These images must then be managed by a database system efficient storage and retrieval. There are many types of image database systems, among which the content-based image retrieval (CBIR) system is the most advanced. CBIR utilizes the metadata of images including the feature data for indexing and searching images. Therefore, the performance of image retrieval is significantly affected by the storage method of the image metadata. There are many features of images such as color, texture, and shape. We mainly consider the shape feature because shape can be identified in any remote sensing while color does not always necessarily appear in some remote sensing. In this paper, we propose a metadata representation and storage method for image search based on shape features. First, we extend MPEG-7 to describe the shape features which are not defined in the MPEG-7 standard. Second, we design a storage schema for storing images and their metadata in a relational database system. Then, we propose an efficient storage method for managing the shape feature data using a Wavelet technique. Finally, we provide the performance results of our proposed storage method.

• 한국컴퓨터산업학회논문지
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• 제2권2호
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• pp.203-210
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• 2001

이진 트리 검색에 관한 관계 모형들을 추정하고 이론 가설들을 검정하기 위하여 중복되지 않는 자연수들을 자료로 하는 3개 이상 7개 이하의 노드를 가진 모든 가능한 이진 검색 트리 들을 생성하였다. 노드 개수 별로 높이 및 균형도 에 따른 이진 검색 트리 생성 확률들을 추정하였으며 노드 개수와 트리의 높이, 검색에 필요한 비교 횟수의 관계를 나타내는 회귀 모형이 구축되었고 이진 검색 트리의 O(1g(n)) 이론이 적합도 검정 절차에 의하여 실험적으로 채택되었다. 이진 검색 트리의 균형에 따른 검색 성능의 유의적 차이들을 통계적으로 증명하기 위하여 균형도에 따라 확률적으로 생성된 이진 검색 트리들을 세 그룹으로 그룹화하고 그룹간의 검색 비교 횟수를 분산 분석 모형에 의하여 비교 분석하였다.

• 한국IT서비스학회지
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• 제12권3호
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• pp.253-271
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• 2013

Innovation becomes norm rather than exception in today's business, and accordingly firms are working on how to make their employees to work smarter using information systems and technologies. Smart work demands virtual collaboration and cooperation among team members in different places and different time. Sharing of knowledge among team members in these innovative activities are critical in every sense for the successful performance. This study explores the antecedents of knowledge sharing among team members in team-based innovation activities. Five factors (pleasure of knowledge sharing, self-efficacy, management support, rewards, and system usage) are identified through extant review of literature and an instrument is adopted and validated from previous studies. The instrument is adminitered against 138 individuals in and across 54 teams in a telecommunication firm. Except self efficacy, all the paths in the proposed research model is confirmed with different levels of relational coefficients towards the levels of knowledge sharing and innovation activities in teams. Surprisingly, findings indicate that intrinsic pleasure of sharing is most critical than management support, organizational rewards or system usage. This study fills the research gap in team management. Findings provide important implications for managing teams in coming virtual and smart environment.

• 한국정보과학회논문지:데이타베이스
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• 제31권1호
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• pp.72-81
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• 2004

오늘날 인터넷 상의 많은 데이타들은 XML의 여러 장점들로 인하여 XML을 이용하여 표현되고 있다. 이렇게 XML 데이타가 늘어가는 것에 비례하여 XML 문서상에서 유용한 정보를 검색하기 위하여 다양한 질의를 빠르고 효율적으로 지원할 수 있는 질의 처리 기법이 요구되고 있다. 그러나 현재까지는 XML 데이타를 위한 질의 최적화 연구는 정규 경로 표현을 다루는 방법론에 국한되어 있다. 본 논문은 새로운 족보 기반 인덱싱 기법을 개발하여 정규 경로 표현뿐 아니라, 단순 경로 표현과 다른 엘리먼트를 참조하고 있는 경로 표현과 같은 다양한 질의 처리를 해결하였다. 또한 이 인덱싱 기법을 객체-관계형 모델에 적용하여 여러 종류의 문서와 다양한 질의 종류에 대해 성능을 평가하였고, 다른 저장 기법과 비교하여 성능의 우수성을 입증하였다.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회 1996년도 추계학술대회발표논문집; 고려대학교, 서울; 26 Oct. 1996
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• pp.78-88
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• 1996

It is important to understand the process of IT diffusion between organizations for meeting effectively IT progress and its changes. The previous studies provide, the process of IT diffusion between organizational members, organizational factors facilitating the assimilation of IT within the organization, and the organizational members' usage of communication channels in the IT adoption process. But they failed to provide comprehensively the diffusion process of IT between organizations. Therefore, an empirical research through a field survey has been performed to examine the diffusion process of RDB with 64 companies to overcome the limits of the previous studies. The purpose of this study is (1) to empirically examine the interaction of companies(prior adopters and potential adopters), (2) to look into the differences of the factors of organizational structure and the periods of RDB adoption process between OAE(Organizations Adopting Earlier) and OAL(Organizations Adopting Later), and the importance of communication channels used in IT planning stage and adoption stage, (3) to inquire into the difference of RDB performance between OAE and OAL. The results of this study indicate that there is no interaction between the prior adopters and the potential adopters. Also, there are great significant differences with regards to variables of CEO's age, CEO's concern on IT, formalization, centralization compensation systems, CIO's attitudes on changes, RDB adoption periods, performance of RDB. In addition, interpersonal channels have been much more used than mass communication channels in both IT planning stage and adoption stage. This study provides good guidelines to the companies and the vendors in shaping the strategies of IT adoption and IT diffusion respectively.

• 전기전자학회논문지
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• 제22권3호
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• pp.693-699
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• 2018

CNN 기반의 객체 인식 성능은 매우 우수한 것으로 보고되고 있지만 모바일 기기의 앱 GUI와 같이 일반적으로 생각하기에 잡음이 적고 분명하게 인식될 수 있을 것으로 기대되는 환경에 적용해보면 인간의 관점에서 매우 유사한 GUI 입력 위젯들이 의외로 잘 인식되지는 않는다는 문제가 발생한다. 본 논문에서는 CNN의 입력 위젯 인식 성능을 향상시키기 위하여 모바일 앱의 GUI를 구성하는 객체들의 관계를 활용하는 방법을 제안한다. 제안 방법에서는 (1) CNN 기반의 객체 인식 도구인 Faster R-CNN을 이용하여 모바일 앱을 구성하는 입력 위젯을 1차 인식한 후 (2) 위젯 인식률 향상을 위하여 객체 간의 관계를 활용하는 방법을 결합하였다. 객체 간의 관계는 표현 공간상에서의 벡터의 평행 이동을 활용하여 표현되었으며, 총 323개의 앱에서 생성한 데이터에 적용한 결과 Faster R-CNN만을 사용한 경우와 비교하여 위젯 인식률을 상당히 개선할 수 있음을 확인하였다.

• The Journal of Asian Finance, Economics and Business
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• 제7권7호
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• pp.113-121
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• 2020

Multi-criteria stock selection is a critical issue for effective investment since the improper stock investment might cause many problems affecting investors negatively. Investors need a range of financial indicators while they are choosing the optimal set of stocks to invest. This study aims to rank the stock of agriculture companies indexed on the Vietnam Stock Exchange Market. The data of 13 agriculture companies during the 2016-2019 periods was analyzed by analytical hierarchy process (AHP) integrated with grey relational analysis (GRA), multi-objective optimization ratio analysis (MOORA), and technique for order performance by similarity to ideal solution (TOPSIS). The AHP method is employed to determine the weights of the proposed financial ratios, and GRA, TOPSIS, and MOORA approaches are used to obtain final ranking. The results indicated that HSL is the top stock with the highest rank and GRA, MOORA, and TOPSIS rankings have strong correlation values between 0.78-1. The findings suggest that the integrated model could be implemented effectively to specific analysis of industries such as oil and gas, textiles, food, and electronics in future research. Further, other techniques like COPRAS, KEMIRA, and EDAS could be employed to evaluate the financial performance of other companies to solve investment problems.

• ETRI Journal
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• 제38권6호
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• pp.1197-1206
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• 2016

Performing continuous skyline queries of dynamic data sets is now more challenging as the sizes of data sets increase and as they become more volatile due to the increase in dynamic updates. Although previous work proposed support for such queries, their efficiency was restricted to small data sets or uniformly distributed data sets. In a production database with many concurrent queries, the execution of continuous skyline queries impacts query performance due to update requirements to acquire exclusive locks, possibly blocking other query threads. Thus, the computational costs increase. In order to minimize computational requirements, we propose a method based on a multi-layer grid structure. First, relational data object, elements of an initial data set, are processed to obtain the corresponding multi-layer grid structure and the skyline influence regions over the data. Then, the dynamic data are processed only when they are identified within the skyline influence regions. Therefore, a large amount of computation can be pruned by adopting the proposed multi-layer grid structure. Using a variety of datasets, the performance evaluation confirms the efficiency of the proposed method.

• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
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• 제8권1호
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• pp.9-16
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• 2002

조인 연산은 관계형 데이타베이스에서와 같이 시간 데이타베이스에서도 시스템 성능에 큰 영향을 미친다. 특히, 시간 조인은 조인 연산 단계 이전에 간격 분할의 최적화가 질의 처리 성능을 결정한다. 이 논문에서는 시간 데이타베이스의 병렬 조인 질의 처리 성능을 개선하기 위해 시간 조인 연산을 위한 시간 간격을 분할하는 최소 분할 기법을 제안하였고, 제안된 간격 분할의 최소 분할점을 결정하는 최소 간격 분할 알고리즘의 유효성은 예제 시나리오를 통해 검증하였으며, 기존 분할 알고리즘에 비해 성능 개선 효과가 있음을 확인하였다.