• 한국멀티미디어학회논문지
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• 제20권8호
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• pp.1447-1455
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• 2017

In a trawl-net simulation, it is very important to process the physical phenomenons resulting from real collisions between a net and fishes. However, because it is very difficult to reconstruct the surface with mass points, many researchers have generally detect the collision using an approximation model employing a sphere, a cube or a cylinder. These approaches occur often result in inaccurate movements of a fish due to the difference between a real-net and a designed-net. So, many systems have manually adjusted a net surface based on actual measurements of mass points. These methods are very inefficient because it needs much times in an adjustment and also causes more incorrect inputs according to a rapid increment in the number of points. Therefore, in this paper, we propose a reconstruction method that it semi-automatically reconstructed trawl-net surfaces using the equation of motion at each mass point in a mass-spring model. To get an easy start in a beginning step of the spread, it enables users to get interactive adjustment on each mass point. We had designed a trawl-net model using geometrical structures of trawl-net and then automatically reconstructed the trawl-net surface using scale-space meshing techniques. Last, we improve the accuracy of reconstructed result by correction user interaction.

• 한국융합학회논문지
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• 제9권1호
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• pp.241-251
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• 2018

본 연구는 지역사회와의 융합을 위해 학교를 기반으로 고위험 문제행동을 보이는 초등학생을 대상으로 실시한 구조화된 인지행동 중재 프로그램의 효과에 관한 예비연구이다. 개발한 프로그램은 준전문가를 통해 실시하여 효과를 검증하였다. 고위험군 선별을 위해 도농복합지역의 한 초등학교 3학년 전체 102명을 대상으로 한국판 아동행동평가척도(K-CBCL)를 실시하였고 문제행동증후군 척도의 T점수가 60점 이상인 고위험군 학생 32명을 선정하여 개입집단과 대조집단으로 나누었다. 인지행동치료를 기반으로 9회기의 구조화된 집단 프로그램을 개발하였고, 심리상담 전공의 대학원생 및 대학생이 전문가의 지도를 받아 개입집단에게 프로그램을 실시하였다. 개입 후 내재화 집단은 내재화 문제, 불안 및 우울증상이 유의하게 감소되었으며 외현화 집단은 외현화 문제, 공격행동에 유의미한 감소를 보였지만, 혼합형 집단에서는 유의미한 변화가 관찰되지 않았다. 질적인 분석을 통해 점수의 의미를 추가적으로 살펴보았다. 결과에 대한 시사점과 연구의 제한점 그리고 후속연구에 대해 제언하였다.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제7권2호
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• pp.75-81
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• 2003

Compact schemes are shown to be effective for a class of problems including convection-diffusion equations when combined with multigrid algorithms [7, 8] and V-cycle convergence is proved[5]. We apply the multigrid algorithm for an semianalytic finite difference scheme, which is desinged to preserve high order accuracy despite of singularities.

• ETRI Journal
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• 제37권4호
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• pp.752-765
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• 2015

We propose a novel post-processing algorithm and its very-large-scale integration architecture that simultaneously uses the passive and active stereo vision information to improve the reliability of the three-dimensional disparity in a hybrid stereo vision system. The proposed architecture consists of four steps - left-right consistency checking, semi-2D hole filling, a tiny adaptive variance checking, and a 2D weighted median filter. The experimental results show that the error rate of the proposed algorithm (5.77%) is less than that of a raw disparity (10.12%) for a real-world camera image having a $1,280{\times}720$ resolution and maximum disparity of 256. Moreover, for the famous Middlebury stereo image sets, the proposed algorithm's error rate (8.30%) is also less than that of the raw disparity (13.7%). The proposed architecture is implemented on a single commercial field-programmable gate array using only 13.01% of slice resources, which achieves a rate of 60 fps for $1,280{\times}720$ stereo images with a disparity range of 256.

• 융복합기술연구소 논문집
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• 제5권2호
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• pp.27-32
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• 2015

Air intakes are an essential component of aircraft engines. They are mainly used to offer uniform airflows to engine faces. Fighter aircraft have to mask the engine face inside the fuselage in order to reduce the Radar Cross Section(RCS). Therefore, offset intakes like a S-Duct are one of promising components for this purpose. During a fight, it is unavoidable that the flow will enter the intakes at some face angles other than zero. In this case, the performance of the aircraft engine will be influenced to the angle of incidence. In this study, the CFD analysis of the semi-circular S-Duct with AR(0.5,0) is performed to investigate the influence of the angle of incidence on the performance of the S-Duct using a distortion coefficient. To consider the adverse pressure gradient, a $k-{\omega}$ SST turbulence model is employed. The secondary flow and flow separation are observed for all computational cases. It is found that the positive incidence angle produces the best performances.

• 한국산업융합학회 논문집
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• 제2권1호
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• pp.35-43
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• 1999

The purpose of this study is to derive the optimal methodology estimating the changes of fluvial hydraulic characteristics due to semi-covering work of urban stream. First, after collecting the data of the daily maximum rainfall of Chungju gaging station, the frequency analysis was carried out with frequency factor method, which includes normal, two-parameter and three-parameter lognormal, Gumbel-Chow, pearson type III, log-pearson type III distribution, and the goodness of fit test was executed by $x^2$-test and Kormogorov-Smimov test. Using the SCS method, the effective rainfall was estimated and the peak flow was calculated by the area-routing method. The HEC-2 model was applied to calculate water surface profiles for steady, gradually varied flow at Kyohyun river system in Chungju city. The model was applied to floodplain and riverbed management to evaluate flood way encroachments and to delineate flood hazard by riverside roadway construction. The model also was used to evaluate effects on water surface profiles of river improvement and levees as well as the presence of bridges or other hydraulic structures in the floodplain.

• 한국산업융합학회 논문집
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• 제23권4_1호
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• pp.541-547
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• 2020

This paper relates a rheo die casting using electromagnetic force, which is one of the representative semi-solid methods for aluminum. The most important factors in electromagnetic stirring would be the melt temperature, sleeve temperature, electromagnetic force, and input time. The effect of the temperature of molten alloy on the direct rheo-casting is assessed in this study. The temperature of the molten alloy is set to 590 ℃ with a solidification of 40%, 600 ℃ with 30%, and 610℃ with less than 20%. Under the condition of 590 ℃ with a solidification of 40%, the whole molten alloy is solidified, causing non-forming during forming process. Meanwhile, under the condition of 600 ℃, where the solidification was 30%, appropriate amount of molten alloy is solidified, filled well into the mold, resulting in good forming, while at 610 ℃ with the solidification of 20%, the molten alloy is not sufficiently solidified and scattered away. The investigation of the defects inside the product with the help of the X-ray equipment shows that the electromagnetic stirring at 590 ℃ with a solidification of 30% produces many air-pores inside the product.

• 융합보안논문지
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• 제16권3_2호
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• pp.25-32
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• 2016

Drone은 원격조정장치에 의한 무인비행 시스템을 말한다. 즉 조종사가 비행체에 직접 탑승하지 않고 지상에서 원격조종(remote piloted)하거나 사전 프로그램 경로에 따라 자동(auto-piloted) 또는 반자동(semi auto-piloted)형식으로 자율 비행하는 시스템이다. 이러한 드론은 초창기에 군사적 목적으로 개발되어 이용되어 왔으나 현재에는 물류 및 재난 지역의 구호품 배송, 무선인터넷 연결 방송, 영상 촬영, 재해 관측, 범죄자 추적 등 다양한 영역에서 활용이 되고 있다. 민간시큐리티 분야에서의 드론의 사용은 많은 장점과 방범의 효율성을 기대할 수 있다. 특정지역의 감시나 정찰, 세밀 탐색, 고공촬영 등 범죄예방에 효과적으로 대처할 수 있고, 범죄자 추적에 대해서도 시시각각 정보를 제공함으로서 범죄자 체포에 용이하게 사용 될 수 있다. 특히 야간의 경우 적외선 카메라를 사용하여 침입자나 사람의 움직임을 찾아낼 수 있고, 재난 현장에서의 수색이나 구조 등의 활동에도 적극 이용될 수 있다.

• 디지털정책학회지
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• 제2권4호
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• pp.17-23
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• 2023

본 논문에서는 중소 규모의 정밀 가공 기업에 대한 생산 가공의 개선을 위하여 기존 공정 방식에 제조 실행 시스템을 적용하고 정밀가공의 데이터를 통합하였다. 이에 따른 기업 내 공정 관리 시스템의 강화, 장비 운용 효율의 증대, 불량률 감소를 통한 생산성 향상 및 작업 공수 감소에 따른 원가 절감률의 차이를 비교 분석하였다. 그 결과 제조 실행 시스템 도입으로 인해 생산 업무 생산성이 7.0% 향상되었고, 제품 불량률은 0.1%p 개선되었다. 제조원가 절감은 10.0%, 납기 준수율은 1.1% 개선되었음을 확인하였다. 추후 본 연구에서 제안한 제조 실행 시스템을 기반으로 추가적인 스마트팩토리 기술을 적용하는 경우 PQCD 지표의 상승으로 인한 가공 산업의 매출 및 이익 증대가 예상된다.

• Journal of applied mathematics & informatics
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• 제5권2호
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• pp.433-448
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• 1998

In this study we use inexact Newton-like methods to find solutions of nonlinear operator equations on Banach spaces with a convergence structure. Our technique involves the introduction of a generalized norm as an operator from a linear space into a par-tially ordered Banach space. In this way the metric properties of the examined problem can be analyzed more precisely. Moreover this approach allows us to derive from the same theorem on the one hand semi-local results of kantorovich-type and on the other hand 2global results based on monotonicity considerations. By imposing very general Lipschitz-like conditions on the operators involved on the other hand by choosing our operators appropriately we can find sharper error bounds on the distances involved than before. Furthermore we show that special cases of our results reduce to the corresponding ones already in the literature. Finally our results are used to solve integral equations that cannot be solved with existing methods.