• Annual Conference of KIPS
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• 2009.04a
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• pp.230-233
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• 2009

본 논문은 볼륨 데이터를 입력받아 계층성을 지원하는 등밀도 표면을 재구성하는 방법을 제안한다. 제안된 방법은 먼저 입력 볼륨 데이터에서 볼륨 피라미드를 구성하고 해상도가 최저인 피라미드의 최상단 볼륨에서부터 셀경계표현 방법을 이용하여 조악한 초기 메쉬를 생성하며, 이 메쉬를 표면축소기법을 사용하여 반복적으로 변형하여 O(3)-인접성 조건하에서 추출한 등밀도점을 잘 근사할 수 있도록 한다. 제안된 방법은 생성되는 표면이 압축이나 점진적인 전송 등과 같은 다중 해상도 알고리즘에 활용될 수 있다는 장점이 있다.

• Journal of the Korean Applied Science and Technology
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• v.34 no.4
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• pp.1112-1120
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• 2017

Petroleum products are composed of various types of hydrocarbon compounds. Like other types of liquids, they presented the variation of density and volume according to temperature change. The method of measuring the density of petroleum products in a liquid phase is based on experimental data obtained mainly for each fractionally distilled petroleum product. In this study, the density and volume changes of kerosene and automotive diesel according to temperature change were measured and the property of change were analyzed. The conversion values were calculated using the density volume conversion table proposed by international standard ASTM. In addition, we analyzed the differences between the reference values and the measured values for the temperature changes specified in the domestic metering law.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.5 no.5
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• pp.167-176
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• 2015

Due to the variety of tourist attractions, many people of the world are visiting annually in Mediterranean area. In this paper, we analyze Mediterranean tourism impact by specific events such as the Arab Spring. In details, we make several density maps based on the position and time information of the geo-tagged photos extracted from Panoramio which is a representative photo sharing website. These density maps should be used to analyze how can specific events affect on Mediterranean tourism. To do this, first, a spatial database is constructed using geo-tag and time information of photo data extracted from Panoramio. Using GIS tool, then, several density maps are produced after performing density process based on spatial databases. Based on these density maps, finally, we analyze visually on Mediterranean tourism impact according to before, progress, and after of the Arab Spring.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2019.05a
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• pp.93-95
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• 2019

일반적으로 항만 내 선박 교통류 평가는 AIS 데이터를 이용하여 수행이 되어져 왔다. AIS 데이터는 선박의 위치 확인에 용이하여 항로상 선박 교통분포 분석에 용이하였다. 하지만, AIS 데이터는 VTS에 저장되어 있는 기간이 짧고, 처리할 데이터의 양이 많은 단점이 있다. 한편, PORT-MIS 선박 입출항 데이터는 10년 이상 저장이 되어 있으며, 통항로상 통계적 선박교통밀도 분석에 활용이 용이하다. 본 연구에서는 PORT-MIS 빅데이터 분석 방법과 선박 입출항 데이터를 항로상의 통항데이터로 변환하는 방법을 개발하여 제시하고자 한다.

• Information and Communications Magazine
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• v.31 no.11
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• pp.35-45
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• 2014

주성분 분석 기법(PCA)는 가장 널리 사용되는 데이터 차원 감소 (dimensionality reduction) 기법으로 알려져 있다. 하지만 데이터에 이상점 (outlier)가 존재하는 환경에서는 성능이 크게 저하된다는 단점을 가지고 있다. Rank-Sparsity(Robust PCA) 기법은 주어진 행렬을 low-rank 행렬과 저밀도(sparse)행렬의 합으로 분해하는 방식으로, 이상점이 많은 환경에서 PCA기법을 효과적으로 대체할 수 있는 알고리즘으로 알려져 있다. 본 고에서는 RPCA 기법을 간략히 소개하고, 그의 적용분야, 및 알고리즘에 관한 연구들을 대해서 알아본다.

• Proceedings of the Korean Information Science Society Conference
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• 2007.10b
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• pp.84-87
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• 2007

진화하는 IT 패러다임에 맞추어 기업의 시스템은 당면한 이슈 처리 뿐만 아니라 변화를 예측하여 비즈니스와 시스템을 진화시킬 수 있는 전략을 수립할 수 있어야 한다. 논문에서는 통신사업자의 특정 도메인인 온라인 서비스 도메인에 대해서 기술 계층과 데이터 계층의 아키텍처 참조 모델을 연구하고 연구 필요성에 대하여 기술한다. 또한 기술 밀 데이터 아키텍처를 분석, 설계하고 품질을 평가하는데 참조할 수 있는 평가 지표를 사용자 관점별로 연구한다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.1075-1076
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• 2013

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.17 no.5
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• pp.77-87
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• 2018

Traffic Density is the most important of the three primary macroscopic traffic stream parameters, because it is most directly related to traffic demand(Traffic Engineering, 2004). It is defined as the number of existing vehicles within a given distance at a certain time. However, due to weather, road conditions, and cost issues, collecting density directly on the field is difficult. This makes studies of density less actively than those of traffic volume or velocity. For these reasons, there is insufficient attempts on divers collecting methods or researches on the accuracy of measured values. In this paper, we used the 'Density Measuring System' based on the synthesise technology of several camera images as a method to measure density. The collected density value by the 'Density Mesuring System' is selected as the true value based on the density define, and this value was compared with the density calculated by the traditional measurement methods. As a result of the comparison, the density value using the fundamental equation method is the closest to the true value as RMSE shows 1.8 to 2.5. In addition, we investigated some issues that can be overlooked easily such as the collecting interval to be considered on collecting density directly by calculating the moment density and the average density. Despite the actual traffic situation of the experiment site is LOS B, it is difficult to judge the real traffic situation because the moment density values per second are observed max 16.0 (veh/km) to min 2.0 (veh/km). However, the average density measured for 15 minutes at 30-second intervals was 8.3-7.9 (veh/km) and it indicates precisely LOS B.

• Journal of the Korea Institute of Building Construction
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• v.17 no.4
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• pp.305-312
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• 2017

To evaluate the reliability of fly ash quality supplied to ready-mixed concrete plant using mass cylinder and hydrometer, in this research, the correlationship between the fly ash properties provided from certification and density measurement with suspension was evaluated. As a result, the reliability of the certification, except fineness and loss on ignition, all properties had a discord. Additionally, in the case of density, fineness, and L.O.I, the relation with the density measured using hydrometer showed high correlation, especially fineness was strongly related with the density measured using hydrometer. Furthermore, according to the comparative analysis with previous research, the fly ash used in this research was similar measurement with raw powder without any refining process, it is considered that the constant error of blaine test or using raw ash sample as a fly ash. In current standard regarding fly ash, the fineness range of class 2 can be changed from $3,000-4,500cm^2/g$ to $3,500-4,500cm^2/g$ for improved quality of fly ash in fineness aspect.

• Journal of Broadcast Engineering
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• v.25 no.5
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• pp.709-722
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• 2020

Point Cloud which is a cluster of numerous points can express 3D object beyond the 2D plane. Each point contains 3D coordinate and color data basically, reflectance or etc. additionally. Point Cloud demand research and development much higher effective compression technology. Video-based Point Cloud Compression (V-PCC) technology in development and standardization based on the established video codec. Despite its high effective compression technology, point cloud service will be limited by terminal spec and network conditions. 2D video had the same problems. To remedy this kind of problem, 2D video is using Scalable High efficiency Video Coding (SHVC), Dynamic Adaptive Streaming over HTTP (DASH) or diverse technology. This paper proposed a density scalability method using SHVC codec in V-PCC.