• 대한기계학회논문집B
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• 제27권4호
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• pp.484-495
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• 2003

This study investigates the flow characteristics of fuel droplets between twin spray for the 4-hole injector used a 4-valve gasoline engine. The injectors for this study were the three types of 4-hole gasoline injector in which orifice diameter was 0.24mm. The spray behavior of twin spray was investigated by means of visualization employed stroboscope. A PDPA system was employed to simultaneously measure the size and velocity of fuel droplets. The 3 dimensional mean velocities. droplet size distributions, SMD and joint probability density function of velocity and droplet size are analyzed at the center of the spray and the center region of twin spray. As a result, the configurations of injector exit such as orifice interval and length of outlet, are very important factors that affect the flow characteristics of fuel droplets at the center region of twin spray.

• 한국추진공학회지
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• 제9권4호
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• pp.66-72
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• 2005

본 연구에서는 초음속 충동형 터빈의 유동특성을 알아보기 위해 소형 초음속 풍동을 설계하였으며 Single pass Schlieren system을 이용하여 유동을 가시화하였다. 실험은 2차원 초음속 노즐과 익렬을 조합하여 블레이드 앞전 형상과 노즐-익렬 간극에 따라 실시하였다. 실험을 통해 충격파를 포함한 복잡한 유동 형태와 노즐-익렬, 충격파-경계층 상호작용 등을 관찰할 수 있었다.

• 한국항공우주학회지
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• 제42권9호
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• pp.723-730
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• 2014

이차유동을 이용한 초음속 동축류 추력편향 제어기법에 대한 실험적 연구가 진행되었다. 쉴리렌 유동가시화 및 로드셀을 이용한 고정확도의 다분력 시험장치를 통하여 이차원 초음속(마하수 2.0) 유동의 추력편향 특성이 관찰되었다. 추력편향각은 부유동의 압력이 점차 커지면서 일시 감소 후 다시 증가하는 V-자형 추세를 보이고 있음이 관찰되었다. 추력편향 유동의 성능을 나타내는 성능계수들의 분석이 이루어졌으며, 보다 높은 성능지표를 나타내는 본 시스템의 운용조건이 제시되었다.

• 한국측량학회:학술대회논문집
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• 한국측량학회 2010년 춘계학술발표회 논문집
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• pp.367-369
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• 2010

The purpose of this study is to develop a campus facility management system, construct 3D graphic data and attribute data of facilities on the Kumoh National Institute of Technology and then verificate the developed system's practicability. Utilized the existing campus facility data from the existing drawings, images, cadastre records and so forth, 3D position data of underground facilities surveyed with a total station and high-resolution aerial photos, 3D realistic models were produced by means of a XD2D software and a XDWORLD Builder Professional software of GIS engines. We intend to embody not only campus guide service in virtual reality space but visualization of 3D virtual campus by providing 2D and 3D data to web space using XDWORLD server soon after. It is expected that the campus facility management system is able to contribute to the integrated management of 3D facility data service, the support of prompt decision-making related to spatial affairs, the work simplification through data holding in common between the members of the staff and so forth.

• 방송공학회논문지
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• 제13권1호
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• pp.86-91
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• 2008

네트워크 데이터 분석에 있어서 추정모델이 얼마나 모집단을 대표하느냐는 반드시 연구되어야 한다. 본 논문에서는 네트워크 데이터의 각 추출 가능한 표준 정보를 이용하여 현재 공개되어 사용하고 있는 MIT Lincoln Lab의 네트워크 데이터와 모델링 된 KDD CUP 99 데이터를 비교 분석한다. 비교, 분석에 있어서 두 데이터에 공통으로 포함되고 표준 정보인 프로토콜 정보를 이용하여 분석한다. 분석은 통계적 분석 방법인 대응 분석 방법을 이용하여 분석하고, SVD를 이용해 2차원 공간에 표현하며, 가중 유클리드 거리를 이용해 네트워크 데이터를 수량화하였다.

• 대한원격탐사학회지
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• 제8권2호
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• pp.131-145
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• 1992

A low cost personal computer and image processing S/W were empolyed to derive Digtal Elevation Model(DEM) of tidal flat from multitemporal LANDSAT TM images, and to create three-dimensional(3D) perspective views of the tidel flat on Komso bay in west coasts of Korea. The method for generation of Digital Elevation Model(DEM) in tidal flat was considered by overlapping techniques of multitemporal LANDSAT TM images and interpolations. The boundary maps of tidal flat extracted from multitemporal images with different water high were digitally combined in x, y, z space with tide in formation and used as an inputcontour data to obtain an elevation model by interpolation using spline function. Elevation errors of less than $\pm$0.1m were achived using overlapping techniques and a spline interpolation approach, respectively. The derived DEM allows for the generation of a perspective grid and drape on the satellite image values to create a realistic terrain visualization model so that the tidal flat may be viewed from and desired direction. As the result of this study, we obtained elevation model of tidal flats which contribute to characterize of topography and monitoring of morphological evolution of tidal flats. Moreover, the modal generated here can be used for simulation of innudation according to tide and support other studies as a supplementary data set.

• 대한수의학회지
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• 제59권2호
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• pp.55-58
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• 2019

This study was performed to examine the visualization and anatomical variants of the hepatic artery with dual-phase computed tomography (CT) angiography and three-dimensional volume rendering imaging analysis in clinically normal dogs. Seven healthy beagle dogs were enrolled and underwent dual CT angiography. Arterial phase images could be obtained with multi-detector CT angiography using the fixed-scan method in these dogs. Contrast enhancement of the hepatic parenchyma was quite minimal because of the unique blood supply system of the liver. In most dogs, the main hepatic arterial branches were the right lateral branch, left branch, and right medial branch. Although hepatic arterial variation appears to be common in dogs, only one dog in this study had the caudate lobar branch as the first branch of the hepatic artery. Further study on a larger number of dogs with CT images will be needed to identify and classify the pattern of hepatic arterial variations.

• 한국분무공학회지
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• 제24권2호
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• pp.51-57
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• 2019

In this study, the spray atomization characteristics of urea injector used in SCR system for construction machinery was analyzed, and the uniformity index at the front of mixer and NOx conversion efficiency were evaluated through numerical analysis. Spray visualization and droplet size/velocity measurement were performed and the measured results were used to verify the spray analysis model to calculate the uniformity index in the exhaust gas after-treatment system. For the flow analysis, STAR-CCM, a three-dimensional CFD, was used and the uniformity index of the SCR system at the front of the mixer was calculated using the droplet dissociation model and the wall collision model. Finally, the DeNOx performance for the average condition of the NRTC driving mode was calculated to understand the NOx conversion efficiency reflecting the exhaust gas temperature. The simulation results show that the uniformity index at the front of mixer was calculated as 0.862 and DeNOx efficiency was 75.9%.

• 한국의류학회지
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• 제47권1호
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• pp.123-136
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• 2023

To develop smart sportswear capable of measuring biometric data, we created a close-fitting pattern using two- and three-dimensional (2D and 3D, respectively) methods. After 3D virtual fitting, the tightness of each pattern was evaluated using image processing of contact points, mesh deviation, and cross-sectional shapes. In contact-point analysis, the 3D pattern showed high rates of contact with the body (84.6% and 93.1% for shirts and pants, respectively). Compared with the 2D pattern, the 3D pattern demonstrated closer contact at the lower chest, upper arm, and thigh regions, where electrocardiography and electromyography were primarily carried out. The overall average gap was also lower in the 3D pattern (5.27 and 4.66 mm in shirts and pants, respectively). In the underbust, waist, thigh circumference, and mid-thigh circumference, the cross-section distance between clothing and body was showed a statistically significant difference and evenly distributed in the 3D pattern, exhibiting more closeness. The tightness and fit of the 3D smart sportswear sensor pattern were successfully evaluated. We believe that this study is critical, as it facilitates the comparison of different patterns through visualization and digitization through 3D virtual fitting.

• 한국컴퓨터정보학회:학술대회논문집
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• 한국컴퓨터정보학회 2022년도 제65차 동계학술대회논문집 30권1호
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• pp.13-16
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• 2022

LSTM과 같은 딥러닝 기법을 이용해 언어모델을 얻는 과정에서 일종의 부산물로 학습 대상인 말뭉치를 구성하는 어휘의 단어벡터를 얻을 수 있다. 단어벡터의 차원을 2차원으로 감소시킨 후 이를 평면에 도시하면 대상 문장/문서의 핵심 어휘 사이의 상대적인 거리와 각도 등을 직관적으로 확인할 수 있다. 본 연구에서는 기형도의 시(詩)을 중심으로 특정 작품을 선정한 후 시를 구성하는 핵심 어휘들의 차원 감소된 단어벡터를 2D 평면에 도시하여, 단어벡터를 얻기 위한 텍스트 전처리 방식에 따라 그 거리/각도가 달라지는 양상을 분석해 보았다. 어휘 사이의 거리에 의해 군집/분류의 결과가 달라질 수 있고, 각도에 의해 유사도/유추 연산의 결과가 달라질 수 있으므로, 평면상에서 핵심 어휘들의 상대적인 거리/각도의 직관적 확인을 통해 군집/분류작업과 유사도 추천/유추 등의 작업 결과의 양상 변화를 확인할 수 있었다. 이상의 결과를 통해, 영화 추천/리뷰나 문학작품과 같이 단어 하나하나의 배치에 따라 그 분위기와 정동이 달라지는 분야의 경우 텍스트 전처리에 따른 거리/각도 변화를 미리 직관적으로 확인한다면 분류/유사도 추천과 같은 작업을 좀 더 정밀하게 수행할 수 있을 것으로 판단된다.