• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.33 no.4
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• pp.287-296
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• 2015

Recent navigation systems provide quick guide services, based on processing real-time traffic information and past traffic information by applying predictable pattern for traffic information. However, the current pattern for traffic information predicts traffic information by processing past information that it presents an inaccuracy problem in particular circumstances(accidents and weather). So, this study presented a more precise predictive traffic information system than historical traffic data first by analyzing route search data which the drivers ask in real time for the quickest way then by grasping traffic congestion levels of the route in which future drivers are supposed to locate. First results of this study, the congested route from Yang Jae to Mapo, the analysis result shows that the accuracy of the weighted value of speed of existing commonly congested road registered an error rate of 3km/h to 18km/h, however, after applying the real predictive traffic information of this study the error rate registered only 1km/h to 5km/h. Second, in terms of quality of route as compared to the existing route which allowed for an earlier arrival to the destination up to a maximum of 9 minutes and an average of up to 3 minutes that the reliability of predictable results has been secured. Third, new method allows for the prediction of congested levels and deduces results of route searches that avoid possibly congested routes and to reflect accurate real-time data in comparison with existing route searches. Therefore, this study enabled not only the predictable gathering of information regarding traffic density through route searches, but it also made real-time quick route searches based on this mechanism that convinced that this new method will contribute to diffusing future traffic flow.

• Proceedings of the Korean Information Science Society Conference
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• 2012.06b
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• pp.132-134
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• 2012

웹 서비스 제품은 그 특성상 패치와 릴리즈가 잦고, 개발주기도 아주 짧다. 따라서 한정된 자원으로 많은 양의 품질 보증 활동이 요구되지만, 실시간으로 이루어지는 TTM(Time to market)을 맞추려면 신속하면서도 높은 수준의 품질을 보증하기 어렵다. 본 논문에서는 탐색적 테스팅 기법과 위험기반 테스팅 기법을 간소화하여, 리스크 분석 시 탐색적 기법으로 판단하여 바로 우선순위를 매기고 테스트를 진행한다. 여기서 리스크 Matrix에 리스크 분석 테이블을 적용하여 테스트 우선순위를 판단한다. 검증의 방법은 적용 전/후 프로젝트 수 대비 TTM 준수율 및 품질을 기준으로 한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.1C
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• pp.34-42
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• 2007

The sphere decoder (SD) has recently been proposed to perform maximum likelihood (ML) decoding for multi-input multi-output systems. Employing a 'breadth-first' searching algorithm for closet points in a lattice, we propose a novel ML decoding scheme for multi-input multi-output systems. Simulation results show that the proposed scheme has the same bit error rate performance as the conventional ML decoders while allowing significantly lower computational burden than the SD.

• Journal of the Korean Society for Library and Information Science
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• v.38 no.1
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• pp.35-50
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• 2004

This study evaluated the applicability of the static hierarchic clustering model to clustering query results in OPAC. Two clustering methods(Between Average Linkage(BAL) and Complete Linkage(CL)) and two similarity coefficients(Dice and Jaccard) were tested on the query results retrieved from 16 title-based keyword searchings. The precision of optimal dusters was improved more than 100% compared with title-word searching. There was no difference between similarity coefficients but clustering methods in optimal cluster effectiveness. CL method is better in precision ratio but BAL is better in recall ratio at the optimal top-level and bottom-level clusters. However the differences are not significant except higher recall ratio of BAL at the top-level duster. Small number of clusters and long chain of hierarchy for optimal cluster resulted from BAL could not be desirable and efficient.

• Journal of the Korea Society of Computer and Information
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• v.8 no.4
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• pp.13-20
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• 2003

Based on the studies on the motion vector distributions estimated on the image sequences, we proposed constrained diamond search (DS) algorithm for fast block-matching motion estimation. By considering the fact that motion vectors are searched within the 2 pixels distance in vertically and horizontally on average, we confirmed that DS algorithm achieves close performance on error ratio and requires less computation compared with new three-step search (NTSS) algorithm. Also, by applying displaced frame difference (DFD) to DS algorithm, we reduced the computational loads needed to estimate the motion vectors within the stable block that do not have motions. And we reduced the possibilities falling into the local minima in the course of estimation of motion vectors by applying DFD to DS algorithm. So, we knew that proposed constrained DS algorithm achieved enhanced results as aspects of error ratio and the number of search points to be necessary compared with conventional DS algorithm, four step search (FSS) algorithm, and block-based gradient-descent search algorithm

• Journal of the Korean Society of Radiology
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• v.8 no.1
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• pp.19-26
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• 2014

This paper suggests techniques to enhance coding time which is a problem in traditional fractal compression and to improve fidelity of reconstructed images by determining fractal coefficient through adaptive selection of block approximation formula. First, to reduce coding time, we construct a linear list of domain blocks of which characteristics is given by their luminance and variance and then we control block searching time according to the first permissible threshold value. Next, when employing three-level block partition, if a range block of minimum partition level cannot find a domain block which has a satisfying approximation error, we choose new approximation coefficients using a non-linear approximation of luminance term. This boosts the fidelity. Our experiment employing the above methods shows enhancement in the coding time more than two times over traditional coding methods and shows improvement in PSNR value by about 1-3dB at the same compression rate.

• Journal of the Korean Society for Library and Information Science
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• v.32 no.1
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• pp.169-187
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• 1998

The primary purpose of this study is to compare printed index and abstract user's behaviours with digital index and abstract user's behaviours, and to verify of structured characteristics of a printed index and abstract. The major findings are as follows: (1) When the research topic is not specified enough, users tend to rely on printed indexes and abstracts search, whereas they utilize digital form in order to do retrospective search in the stage of research when the topic is determined. (2) Printed index and abstract users are expecting small number of literatures in search, whereas digital index and abstract users are expecting large number of literatures to be found The former are more satisfied with the result of search than the latter. (3) Digital index and abstract users experience more search failure than printed Index and abstract users. When they fail to find wanted materials, both users turn to the other form of indexes and abstracts. (4) Printed index and abstract users shows significantly less knowledge on online searching than digital index and abstract users.

• Journal of Korea Multimedia Society
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• v.12 no.10
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• pp.1486-1498
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• 2009

Modem efforts on digitizing electronic books focus on preserving authentic image representation of the original sources. Unlike the text-based format, it is difficult to recognize the information in the image, so the new format requires new tools to help users to access, process, and make sense of digital information. This paper presents an approach which assists users of these image sources by giving them a combination of annotation and social navigation support. Especially in the education domain, the proposed technique improves the usability of online education system. This approach is currently fully implemented and under evaluation in a classroom study.

• Journal of Internet Computing and Services
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• v.11 no.1
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• pp.59-69
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• 2010

With the growing number of web services, there arise issues of finding suitable services. But, the traditional keyword search method is insufficient for two reasons: (1) this does not capture the underlying semantics of web services. (2) this does not suffice for accurately specifying users' information needs. In order to overcome limitations of this keyword search method, we propose a novel syntactic analysis and ontology learning method. The syntactic analysis method gives us a breadth of coverage for common terms, while the ontology learning method gives a depth of coverage by providing relationships. By combining these two methods, we hope to improve both the recall and the precision. We describe an experimental study on a collection of 508 web services that shows the high recall and precision of our method.

• KSCI Review
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• v.2 no.1
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• pp.130-139
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• 1995

This paper suggests the method to shorten the search area by using edge detection and subimage partition. For the purpose reduce encoding time, The Domain areas are reduced 1/64 by partitioning original image to subimage, and classified them into edge area and shade area so that detect only the area in the same class. for achieving an encoding with good fidelity, tried to differ the search method as the threshold value of edge which is included in subimage, and compared the compression rate and fidelity when set the size of range block as $4{\times}4$ and $8{\times}8$.