• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 ITC-CSCC -1
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• pp.441-445
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• 2000

This study is to segment white matter, gray matter, and cerebrospinal fluid(CSF) on a brain MR image of coronal section and to calculate the volume of each. First, we segmented the whole region of a brain from a black colored background, a skull and a fat layer. Then, we calculated the partial volume of each component, which was present in scanning finite thickness, with the arithmetical analysis of gray value from the internal region of a brain showing the blurring effects on the basis of the MR image forming principle. Calculated partial volumes of white matter, gray matter and CSF were used to determine the threshold for the segmentation of each component on a brain MR image showing the blurring effects. Finally, the volumes of segmented white matter, gray matter, and CSF were calculated. The result of this study can be used as the objective diagnostic method to determine the degree of brain atrophy of patients who have neurodegenertive diseases such as Alzheimer’s disease and cerebral palsy.

• 한국통신학회논문지
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• 제29권12B호
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• pp.1037-1041
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• 2004

본 논문에서 위성신호를 매개로 원격지의 로컬클럭이 기준신호에 동기되는 새로운 개념의 슬레이브를럭 시스템을 제안하였으며 이 방식에 의한 실용화 가능성을 확인하였다. 새로이 제시하는 방식은 단계적인 물리계층에 의해 동기되던 기존의 방식에 비해 모든 슬레이브 국소들이 동일한 계위의 품질로 유지될 수 있는 등의 여러 가지 구조적인 장점을 지니고 있다. 슬레이브클럭 시스템의 측정결과 10-12 수준의 주파수정확도를 유지하였으며 ITU-T의 권고(G.811)를 만족하는 MTIE 특성을 보여주었다. 현재 전체적으로 자동화기능을 갖는 초기모델이 구현되었으며 가까운 시일 내에 상용화연구를 통해 통신망 동기용 노드클릭으로 사용될 수 있으리라 기대한다.

• 한국전산유체공학회지
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• 제12권4호
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• pp.68-73
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• 2007

Computational Fluid Dynamics (CFD) approach is now playing an important role in the engineering process in these days. Generating proper grid system in time for the region of interest is prerequisite for the efficient numerical calculation of flow physics using CFD approach. Grid generation is, however, usually considered as a major obstacle for a routine and successful application of numerical approaches in the engineering process. CFD approach based on the unstructured grid system is gaining popularity due to its simplicity and efficiency for generating grid system compared to the structured grid approaches, especially for complex geometries. In this paper an automated triangular surface grid generation using CAD(Computer Aided Design) surface data is proposed. According to the present method, the CAD surface data imported in the STL(Stereo-lithography) format is processed to identify feature edges defining the topology and geometry of the surface shape first. When the feature edges are identified, node points along the edges are distributed. The initial fronts which connect those feature edge nodes are constructed and then they are advanced along the CAD surface data inward until the surface is fully covered by triangular surface grid cells using Advancing Front Method. It is found that this approach can be implemented in an automated way successfully saving man-hours and reducing human-errors in generating triangular surface grid system.

• 전기전자학회논문지
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• 제15권4호
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• pp.261-266
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• 2011

본 논문에서는 LED 가로등의 소비 전력을 줄이고 수명 및 LED 모듈의 열효율을 높이기 위한 효율적인 새로운 조명기기 LED 점등제어 시스템을 제안한다. 제안된 새로운 조명기기 점등제어 시스템은 조도를 측정하여 주변 조도에 따라 4단계로 구분하고 자동 패턴 조명 알고리즘을 적용한다. 그리고 단계검사를 통해 완전대칭을 형성하는 마방진 패턴에 교차점등 알고리즘을 적용하여 설정된 시간동안 점등을 하게 된다. 실험분석 결과, 기존의 조명 시스템과 비교하여 발열량과 소비전력이 최대 30%이상 감소되었고 LED의 수명이 최대 60%이상 향상되었기 때문에 LED 가로등에 적용할 경우 안정적이고 높은 에너지 효율성을 얻을 수 있다.

• Journal of Computational Design and Engineering
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• 제1권1호
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• pp.13-26
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• 2014

Recently, renovations of plant equipment have been more frequent because of the shortened lifespans of the products, and as-built models from large-scale laser-scanned data is expected to streamline rebuilding processes. However, the laser-scanned data of an existing plant has an enormous amount of points, captures intricate objects, and includes a high noise level, so the manual reconstruction of a 3D model is very time-consuming and costly. Among plant equipment, piping systems account for the greatest proportion. Therefore, the purpose of this research was to propose an algorithm which could automatically recognize a piping system from the terrestrial laser-scanned data of plant equipment. The straight portion of pipes, connecting parts, and connection relationship of the piping system can be recognized in this algorithm. Normal-based region growing and cylinder surface fitting can extract all possible locations of pipes, including straight pipes, elbows, and junctions. Tracing the axes of a piping system enables the recognition of the positions of these elements and their connection relationship. Using only point clouds, the recognition algorithm can be performed in a fully automatic way. The algorithm was applied to large-scale scanned data of an oil rig and a chemical plant. Recognition rates of about 86%, 88%, and 71% were achieved straight pipes, elbows, and junctions, respectively.

• 정보통신설비학회논문지
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• 제3권2호
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• pp.11-17
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• 2004

In this paper we propose a new conceptual system for a network clock in which all node clocks are simultaneously synchronized to the national standard by intermediation parameter of satellite time. Experiments have shown the possibility of its adoption by real networks. The new proposed method has various structural benefits, in particular all node clocks can be kept at the same hierarchical quality in contrast to the existing method. The measurement results show that the accuracy of the experimental slave clock system can be kept within a few parts In 1012 and the MTIE (Maximum Time Interval Error) sufficiently meets ITU-T G.811 for the primary reference clock. A prototype system with fully automatic operational functions has been realized at present and is expected to be directly used for communication network synchronization in the near future.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.390-392
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• 2003

Video mosaicing techniques have been widely used in virtual reality environments. Especially in GIS field, video mosaics are becoming more and more common in representing urban environments. Such applications mainly use spherical or panoramic mosaics that are based on images taken from a rotating camera around its nodal point. The viewpoint, however, is limited to location within a small area. On the other hand, 2D-mosaics, which are based on images taken from a translating camera, can acquire data in wide area. The 2D-mosaics still have some problems : it can‘t be applied to images taken from a rotational camera in large angle. To compensate those problems , we proposed a novel method for creating video mosaics in 3D space. The proposed algorithm consists of 4 steps: feature -based optical flow detection, camera orientation, 2D-image projection, and image registration in 3D space. All of the processes are fully automatic and successfully implemented and tested with real images.

• 한국어교육
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• 제23권1호
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• pp.77-100
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• 2012

This study investigates issues in relation to text segmenting, in particular, line breaks in Korean language textbooks. Research on L1 and L2 reading has shown that readers process texts by chunking (grouping words into phrases or meaningful syntactic units) and, therefore, phrase-cued texts are helpful for readers whose syntactic knowledge has not yet been fully developed. In other words, it would be important for language textbooks to avoid awkward syntactic divisions at the end of a line, in particular, those textbooks for beginners and intermediate level learners. According to our analysis of a number of major Korean language textbooks for beginner-level learners, however, many textbooks were found to display line-breaks of awkward syntactic division. Moreover, some textbooks displayed frequent instances where a single word (or eojeol in the case of Korean) is split between different lines. This can hamper not only learners' learning of the rules of spaces between eojeols in Korean, but also learners' development in automatic word recognition, which is an essential part of reading processes. Based on the findings of our textbook analysis and of existing research on reading, this study suggests ways to overcome awkward line-breaks in Korean language textbooks.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2016년도 학술발표회
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• pp.190-190
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• 2016

The Water, Energy, and Food (WEF) nexus is an emerging concept for sustainable resources planning and management. The three valuable resources are inevitably interconnected, that is, it takes water to produce energy; it takes energy to extract, treat, and distribute water; and both water and energy are required to produce food. Although it is challenging to fully understand the complicated interdependency, a few studies have been devoted to interpret the concept and develop the assessment tools. The tools were mainly developed for nation-wide simulations without considering inter-basin or inter-state resources trade. This study tries to present an idea to develop and implement the WEF nexus simulation model in regional scale by advancing the existing nation-wide model with additional capability to simulate the inter-basin trade. This simulation could help local planners and engineers to determine optimal policies and infrastructure solutions to reach and ensure local demand satisfaction. The simulation model is implemented in hypothetical areas with different conditions of WEF demands and supplies. Although the inter-basin trade scenarios are simulated manually, it shows that the inter-basin resources trade could enhance the resources security for a longer time period. In future, an optimization model might be developed to provide the automatic calculation to reach optimum amount of WEF for the trade, which can be a helpful tool in decision making process.

• 대한방사성의약품학회지
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• 제5권1호
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• pp.48-53
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• 2019

A bone metastasis is an important factor for prognosis and treatment of breast or prostate cancer patients. [$^{18}F$]Sodium fluoride ([$^{18}F$]NaF) is a PET radiopharmaceutical that can detect bone metastasis. Conventional [$^{18}F$]NaF production process included radioactive metal impurities because the product was prepared by adding saline after beam irradiation to $[^{18}O]H_2O$. In this study, we apply the method of removing radionuclidic impurities. To meet the criteria prescribed by GMP in quality control, we designed the custom-made [$^{18}F$]NaF automatic module. The mean radiochemical yield was $82.1{\pm}4.4%$ (n = 32) productions for 3 years) and the total preparation time was 4 min. The final produced [$^{18}F$]NaF solution meets the USP criteria for quality control. Thus, this fully automated system is validated for clinical use.