• 대한원격탐사학회지
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• 제11권1호
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• pp.47-64
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• 1995

In this paper, an algorithm that finds man-made structures in a praylevel aerial images is proposed to perform stereo matching. An extracted contour of buildings must have a high accuracy in order to get a good feature-based stereo matching result. Therefore this study focuses on the use of edge following in the original image rather than use of ordinary edge filters. The Algorithm is composed of two main categories; one is to find candidate regions in the whole image and the other is to extract exact contours of each building which each candidate region.. The region growing method using the centroid linkage method of variance value is used to find candidate regions of building and the contour line tracing algorithm based on an adge following method is used to extract exact contours. The result shows that the almost contours of building composed of line segments are extracted.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1988년도 전기.전자공학 학술대회 논문집
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• pp.628-631
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• 1988

This paper describes a fingerprint classification on the basis of feature points(whorl, core) and feature vector and uses a syntactic approach to identify the shape of flow line around the core. Fingerprint image is divided into 8 by 8 subregions and fingerprint region is separated from background. For each subregion of fingerprint region, the dominant ridge direction is obtained to use the slit window quantized in 8 direction and relaxation is performed to correct ridge direction code. Feature points(whorl, core, delta) are found from the ridge direction code. First classification procedure divides the types of fingerprint into 4 class based on whorl and cores. The shape of flow line around the core is obtained by tracing for the fingerprint which has one core or two core and is represented as string. If the string is acceptable by LR(1) parser, feature vector is obtained from feature points(whorl, core, delta) and the shape of flow line around the core. Feature vector is used hierarchically and linearly to classify fingerprint again. The experiment resulted in 97.3 percentages of sucessful classification for 71 fingerprint impressions.

• Journal of Astronomy and Space Sciences
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• 제24권1호
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• pp.69-78
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• 2007

Earth-Sun-Heliosphere Interactions Experiments(EARTHSHINE) 미션의 주 탑재체인 Albedo Monitor and Radiometer(Amon-Ra) 광학계는 최초로 제1 라그랑제 지점(Lagrange point 1) 주위의 혜일로(Halo) 궤도에 위치하여 태양 복사 활동 및 지구 반사율 변화를 1% 정확도 이내로 측정함으로서 현존하는 지구 반사율 추이의 모순을 해결할 수 있는 과학적 측정 자료를 제시하는데 그 목적을 가지고 있다. 이에 이미 개발된 광학 성능 검증용 Amon-Ra 광학계의 가시광채널 시험 모델 및 광선 추적 기법을 이용한 통합적 광선 추적 end-to-end 과학 임무 성능 평가 수치 모사 기법을 확립하였으며, 개발된 기법을 이용하여 실제 제작된 Amon-Ra 광학계를 제1라그랑제 지점에 위치시키고 태양과 지구 밝기를 다양하게 변화시킨 후 광학계에 입사되는 에너지 복사량을 수치 모사로 측정하였다. 관측된 지구 및 태양 밝기로부터 지구 반사율 변환을 위하여 각 분포 모델(GLobal Angular Distribution Model, ADM)을 이용하였으며 수치 모사에 의한 지구 반사율 측정 결과를 Amon-Ra 광학계의 측정 오차 범위인 ${\pm}0.28%$와 비교함으로서 개발된 end-to-end 성능 검증 기법의 계산 정밀도를 확인하였다. 이는 기존의 광학계 성능 검증법의 한계를 뛰어넘어 광학계 성능 평가를 실시간으로 검증할 수 있다는 점에서 큰 의의를 지닌다.

• 천문학회보
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• 제40권2호
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• pp.54.1-54.1
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• 2015

We observed 38 Planck Cold Clumps (PCCs) in the $850{\mu}m$ dust continuum emission using the JCMT/SCUBA-2, and detected the emission in 15 clumps containing dense cores. In this poster we present the preliminary results. The PCCs are cold, dense, and thus, they are considered as objects in the early evolutionary stages of star formation. The sources in our sample were selected based on the Purple Mountain Observatory (PMO) 13CO (1-0) integrated intensity maps. In order to examine whether these cores detected in $850{\mu}m$ continuum have potential to be prestellar cores, we compare each core mass estimated from the $850{\mu}m$ continuum with the Virial mass and Bonnor-Ebert (BE) mass calculated from the 13CO (1-0) or C18O (1-0) spectra. By comparing the two column densities from the dust continuum and the 13CO (1-0) or C18O (1-0) line, we also derive the CO depletion factor, which could be an indicator of core evolution. The moment maps of the 13CO (1-0) line are used to study the physical properties (e.g. kinematics, turbulence) of PCCs. We investigate difference between the sources with and without detectable $850{\mu}m$ emission to study the formation conditions of dense cores.

• 한국멀티미디어학회논문지
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• 제7권4호
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• pp.579-591
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• 2004

본 논문에서는 직선과 곡선으로 구성된 단순한 도면으로부터 곡선을 검출한 다음에 곡선을 원형 아크로 분할하는 방법을 제안한다. 본 논문의 방법에서는 먼저 선의 중심점을 찾은 다음에 연결된 중심점을 추적하여 선분을 검출한다. 그 다음에는 선분의 양 끝에서 선분의 방향을 이용하여 이웃한 선분을 검출하여 선분을 확장해 나간다. 선분을 확장한 다음에는 직선을 제거하고 곡선만 남긴 다음에 재귀적 분할 방법을 이용하여 곡선을 아크들의 집합으로 분할한다. 본 논문에서는 기존의 벡터화 소프트웨어와 벡터 기반 아크 분할 방법과 비교 실험을 수행하였다. 실험 결과에 의하면 본 논문에서 제안된 방법이 기존의 방법에 비하여 교차점을 가지는 곡선에 대하여 보다 정확하게 아크로 분할하였다.

• 대한의용생체공학회:의공학회지
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• 제14권2호
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• pp.163-167
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• 1993

We developed a ventricular assist device(VAD) to be used as a bridge to heart transplantation or a circulatory assist device for patients with end-stage heart disease or poor myocardial function after cardiac surgery. It is a pneumatic and diaphragm-type VAD and its stroke volume is 90 cc. The upper housing and diaphragm is made of a segmented polyurethane and the lower back plate is made of a polycarbonate. Two Carbomedics$^R$ mechanical valves are used as inlet and outlet valves. It was tested in vitro and the cardiac output of the VAD was 7 L/min at a heart rate of 70 bpm. The line pressure from a pressure transducer inserted in the pneumatic line was recorded and compared with the ideal pressure tracing.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권10호
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• pp.4698-4716
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• 2017

Wireless signal transmission is influenced by environmental effects. These effects have also been challenging for Vehicular Ad hoc Network (VANET) in real-time communication. More specifically, in an urban environment, with high mobility among vehicles, a vehicle's status from the transmitter can instantly trigger from line of sight to non-line of sight, which may cause loss of real-time communication. In order to overcome this, a deterministic signal propagation model is required, which has less complexity and more feasibility of implementation. Hence, we propose a realistic path loss model which adopts ray tracing technique for VANET in a grid urban environment with less computational complexity. To evaluate the model, it is applied to a vehicular simulation scenario. The results obtained are compared with different path loss models in the same scenario based on path loss value and application layer performance analysis. The proposed path loss model provides higher loss value in dB compared to other models. Nevertheless, the performance of vehicle-vehicle communication, which is evaluated by the packet delivery ratio with different vehicle transmitter density verifies improvement in real-time vehicle-vehicle communication. In conclusion, we present a realistic path loss model that improves vehicle-vehicle wireless real-time communication in the grid urban environment.

• 통상정보연구
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• 제8권2호
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• pp.141-162
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• 2006

This paper focuses on the phenomenon that international payment system is essential as reverse action of delivery or supply of digital goods in global transactions. In order to impose the customs duties on imported goods in global on-line transactions, the imposition of tariff by tracing the payment process when business transaction is occurring is recommended. The purpose of this study is to review the countermeasures for effective tariff imposition system by using the model of the main payment tools in global transactions. Some models reviewed in this paper are as follows : i) a model of withholding taxes at the source by the credit company ii) a model of self declaration by the importer iii)a model of registering by overseas company iv) a model of negotiating after the taxation at the export country This study is different from existing preceding research at the point of view of presenting 4 models and doing appraisal by each model. It should be done more in depth and various study on the model of the tariff imposition system about the models reviewed at this paper. Systematic and reasonable alternatives which are actually adoptable at the system should also be studied and examined carefully. Because it is required that tariff imposition system on the digital goods should be harmonized with that of traditional business in order to obtain effectiveness and rightfulness, and especially, in order to get justness for the imposition a tariff on digital goods, the process of tax imposition should be predictable and be sure to get the fairness by enhancing the equilibrium, impartiality and transparency.

• 대한조선학회논문집
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• 제49권3호
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• pp.254-263
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• 2012

The survivability of warship is assessed by susceptibility, vulnerability and recoverability. Essentially, a vulnerability assessment is a measure of the effectiveness of a warship to resist hostile weapon effects. Considering the shot line and its penetration effect on the warship, present study introduces the procedural aspects of vulnerability assessments of warship. Present study also considers the prediction of penetration damage to a target caused by the impact of projectiles. It reflects the interaction between the weapon and the target from a perspective of vulnerable area method and COVART model. The shotline and tracing calculation have been directly integrated into the vulnerability assessment method based on the penetration equation empirically obtained. A simplified geometric description of the desired target and specification of a threat type is incorporated with the penetration effect. This study describes how to expand the vulnerable area assessment method to the penetration effect. Finally, an example shows that the proposed method can provide the vulnerability parameters of the warship or its component under threat being hit through tracing the shotline path thereby enabling the vulnerability calculation. In addition, the proposed procedure enabling the calculation of the component's multi-hit vulnerability introduces a propulsion system in dealing with redundant Non-overlapping components.

• 한국항공우주학회지
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• 제48권7호
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• pp.497-504
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• 2020

초음속 비행으로 인해 발생하는 소닉붐을 해석하여 소닉붐의 소음 강도와 대기 전파 특성에 예측할 수 있는 기법을 개발하였다. 소닉붐은 환경 문제를 유발하므로 지상에서 계측되는 소음 강도가 매우 중요한데 본 연구에서는 개략 분석 기법을 이용하여 비행체의 물리량과 비행 정보로부터 계측지 거리에 따른 음압을 산출하였다. 소닉붐의 지상 계측을 위해 비행체에서 발산되는 충격파의 대기 전파 특성을 예측해야하며 이를 위해 시선벡터법과 음선추적기법을 이용하였고, 대기 밀도의 고도별 분포에 따른 굴절을 고려하였다. 개발된 기법을 이용하여 실제 초음속 비행체의 소닉붐을 예측하였고 측정결과와 잘 일치하였다.