• Title/Summary/Keyword: 김영기

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A Study on Lifting Problem of Hydrofoil Using Robin Boundary Condition (혼합경계조건에 의한 수중익 해석에 관한 연구)

  • I.S. Moon;C.S. Lee;Y.G. Kim
    • Journal of the Society of Naval Architects of Korea
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    • v.30 no.3
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    • pp.41-50
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    • 1993
  • This paper compares various potential based panel methods for the analysis of two-dimensional hydrofoil. The strength of singularity on each panel is assumed to be constant or linear. Robin boundary condition as well as Neumann and Dirichlet boundary conditions are applied to various formulations to evaluate the accuracies of the methods. Pressures and lifts are computed for various two-dimensional hydrofoil geometries and are compared with the analytic solutions. Extensive studies are performed on the local errors near the trailing edge, known to be sensitive to the foil geometry with sharp trailing edge and high camber. Robin boundary condition with the perturbation velocity potential formulation shows the best accuracy and convergence rate.

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A study on the Population and Public Health Policies in East European Countries (동구 제국의 인구 및 보건의료정책에 관한 종합적 연구)

  • 안계춘;김영기
    • Korea journal of population studies
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    • v.11 no.1
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    • pp.117-130
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    • 1988
  • Though most of East European coutries seem to hold a pronatalist policy, they approve of family planning and provide contraceptive services. One of the most popular contraceptive method has traditionally been the coitus interruptus in these countries. One of the major reasons for adopting family planning is to decrease the incidence of induced abortion has been closely related to the popular use of coitus interruptus in these countries. Most of the East European countries liberalized induce abortion legally mainly to neutralize the wide practice of illegal abortion. However, the practice of induced abortion is under the strict control of the public health authorities in these countries. Migration and redistribution of population of population are mostly under the control of the state in these socialist countries. Policies on migration and redistribution are usually carried out to achieve the general goal of socio-economic development plan of the states. Both incentive measures and control measures are mobilized to affect the internal migration and redistribution of population. With respect to public health East European countries are characterized by the socialized medicine following the Soviet model. Public health measures and medical practice are controlled by the state and highly centralized in many countries except Yugoslavia. They place much emphasis on preventive medicine, primary health care, occupatinal and industrial medicine, and health education. Private sectors in medical practice do not exist in these countries of Eastern Europe.

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A Research on Development of Applique Armor Kit for Design of Manufacturing Technology based on the Reverse Engineering (역설계 기반 제조기술 설계를 통한 방탄용 부가장갑킷트 개발에 관한 연구)

  • Ko, Dong Hyeon;Moon, Tae Sang;Kim, Young Ki
    • Journal of Korean Society for Quality Management
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    • v.49 no.3
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    • pp.233-243
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    • 2021
  • Purpose: The study focused on localization of the enhanced applique armor kit (EAAK), which are applied to Korea Assault Amphibious Vehicle (KAAV). Methods: For this propose, we developed the manufacturing technology by analyzing the original products. Considering the conditions used in the military, we made the test evaluation criteria. Results: In results, The EAAK developed through this research performs equivalent performance compared to Rafael, Co. Thus, It is possible not only stably supply a parts of EAAK for maintenance, but also to reduce costs due to import substitution effect. Conclusion: It is expected that the manufacturing technology and test evaluation criteria accumulated through this study can be used in the localization of similar parts.

Influential Factors on Teaching Evaluation Scores in Engineering Subjects: Participating in CTL Program and Making of CQI (공학 교과목의 강의평점에 영향을 미치는 요인: CTL 프로그램 참여와 CQI 작성을 중심으로)

  • Kim, Youngki;Hur, Youngju
    • Journal of Engineering Education Research
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    • v.22 no.3
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    • pp.59-67
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    • 2019
  • The purpose of this study is to analyze that hours for participating in CTL program and whether or not make of CQI have a effect on the student evaluation about teaching of engineering professor. This inquiry have done a multiple regression analysis that student evaluation grade of teaching on 2018-1st semester of 240 engineering subjects of N University in Chungcheongnam-do as dependent variable, and background factors and work factors as independent variable. Research results is follows. First, employment type haven't a effect on teaching evaluation scores. And subject type, student' concentration of class, teaching evaluation pre-scores have a positive effect on teaching evaluation rating, but student number have a negative effect. Second, hours for participating in CTL program haven't a effect on teaching evaluation scores, but to make of CQI report have a positive effect on teaching evaluation scores. And I suggested to make CQI for improve teaching evaluation scores and manage the quality of education.

Design and Implementation of Object Detector based on IoMT Standard (IoMT 표준 기반 Object Detection 서비스 제공을 위한 미디어 분석 서비스 운용 기술)

  • Kum, Seung Woo;Moon, Jaewon;Kim, Youngkee
    • Proceedings of the Korean Society of Broadcast Engineers Conference
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    • 2019.06a
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    • pp.296-297
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    • 2019
  • 최근의 IoT 기술의 발전은 다양한 형상, 네트워크 특징 및 서비스 아키텍쳐를 가지는 IoT 기기, 서비스 및 단말을 활용한 서비스의 발전을 가져오고 있다. 특히 OneM2M, OCF 등의 표준기구등은 다양한 IoT 기기 및 서비스 아키텍쳐에 대한 정의를 최근 수년간 진행해 오고 있으며, 이러한 IoT 서비스는 단순히 기기의 원격 상태 확인 및 제어 뿐만 아니라, 클라우드 및 AI 기술과의 연계를 통하여 그 서비스 영역을 지속적으로 확장 중에 있다. 이 중 Internet of Media Things 표준은 다양한 미디어 기반 서비스를 Thing으로 표현하여 다양한 Thing과의 연계 방안을 제시하고 있다. 본 논문에서는 기존에 다양한 기법을 통하여 연구 및 구현되고 있는 영상 기반 서비스를 Internet of Media Things 표준 기반으로 구현하기 위한 방법을 제시한다. 기존 영상 분석 기술은 대부분 정확도의 향상에 그 목적을 가지고 있어 서비스 형태로 제공하고 타 기기와의 연계성을 제공하기 위한 추가적인 기술간 연계가 필요하다. 본 논문에서는 Yolo v3 기반의 Face Detection 기술에 대하여, 해당 기술을 Internet of Media Things 표준으로 표출하기 위한 요구사항을 파악하고 실제 구현하기 위한 방안에 대하여 검토한다.

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A Study on Deriving an Optimal Route for Foreign Tourists through the Analysis of Big Data (빅데이터 분석을 통한 외국인 관광객을 위한 최적 경로 도출)

  • Park, Seong-Taek;Kim, Young-Ki
    • Journal of Convergence for Information Technology
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    • v.9 no.10
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    • pp.56-63
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    • 2019
  • The purpose of this paper is to derive an optimal route for foreign tourists in Korea. To that end, the data gained from domestic tourist portal sites was analyzed with a big data analytics tool R. The destinations most visited by inbound foreign tourists, the shortest route and the most economical route were derived from the analysis results. The findings suggest original Korean culture is the factor for successful tourist destinations and relevant products, and will serve as some reference data conducive to planning the tourist products in practice.

Effect of Culture Medium Vitamin Concentration of Culture Medium on Ethanol Production in Syngas Fermentation (합성가스 발효에서 배지 내 Vitamin 농도의 에탄올 생산에 대한 영향)

  • Im, Hongrae;An, Taegwang;Park, Soeun;Kim, Young-Kee
    • New & Renewable Energy
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    • v.17 no.3
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    • pp.8-15
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    • 2021
  • In this study, we assessed the effect of vitamin components (such as biotin, thiamine-HCl, and folic acid) on microorganism microbial growth and ethanol production was examined to enhance increase the ethanol concentration in the Clostridium autoethanogenum culture process using syngas as a sole carbon source. Biotin and folic acid concentrations of 0.2, 2, 20, and 100 ㎍/L were used in the culture experiments at 0.2, 2, 20, and 100 ㎍/L concentrations. The maximum ethanol concentrations of 2.81 g/L and 3.12 g/L were obtained by adding at 0.2 ㎍/L biotin and folic acid, respectively. Moreover, Thiaminethiamine--HCl at concentrations of 0.5, 5, 50, and 250 ㎍/L were was examined evaluated to in the culture experiments. The maximum ethanol concentration of 2.84 g/L was observed at 0.5 ㎍/L of thiamine--HCl. As a resultThus, the optimized concentrations of biotin, thiamine--HCl, and folic acid were determined at 0.2, 0.5, and 0.2 ㎍/L, respectively, for enhancing increasing the ethanol production. In conclusion, the maximum ethanol production was obtained by adding the minimal concentration of vitamins in C. autoethanogenum culture.

Development of Humanoid Robot HUMIC and Reinforcement Learning-based Robot Behavior Intelligence using Gazebo Simulator (휴머노이드 로봇 HUMIC 개발 및 Gazebo 시뮬레이터를 이용한 강화학습 기반 로봇 행동 지능 연구)

  • Kim, Young-Gi;Han, Ji-Hyeong
    • The Journal of Korea Robotics Society
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    • v.16 no.3
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    • pp.260-269
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    • 2021
  • To verify performance or conduct experiments using actual robots, a lot of costs are needed such as robot hardware, experimental space, and time. Therefore, a simulation environment is an essential tool in robotics research. In this paper, we develop the HUMIC simulator using ROS and Gazebo. HUMIC is a humanoid robot, which is developed by HCIR Lab., for human-robot interaction and an upper body of HUMIC is similar to humans with a head, body, waist, arms, and hands. The Gazebo is an open-source three-dimensional robot simulator that provides the ability to simulate robots accurately and efficiently along with simulated indoor and outdoor environments. We develop a GUI for users to easily simulate and manipulate the HUMIC simulator. Moreover, we open the developed HUMIC simulator and GUI for other robotics researchers to use. We test the developed HUMIC simulator for object detection and reinforcement learning-based navigation tasks successfully. As a further study, we plan to develop robot behavior intelligence based on reinforcement learning algorithms using the developed simulator, and then apply it to the real robot.

Prediction of Steady Performance of a Propeller by Using a Potential-Based Panel Method (포텐셜을 기저로한 패널법에 의한 프로펠러의 정상 성능 해석)

  • Kim, Young-Gi;Lee, Jin-Tae;Lee, Chang-Sup;Suh, Jung-Chun
    • Journal of the Society of Naval Architects of Korea
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    • v.30 no.1
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    • pp.73-86
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    • 1993
  • This paper describes a potential-based panel method for the prediction of steday performance of a marine propeller operating in a uniform oncoming flow. An integral equation with unknown dipole strengths is formulated by distributing the normal dipoles and/or sources on the blade and hub surfaces and the wake sheet, and is solved numerically upon discretization. A hyperboloidal panel has been adopted to compute the potential induced by a normal dipole on a non-planar quadrilateral panel. The Kutta condition is satisfied by iteratively annulling the pressure jumps at the trailing edge. Extensive convergence tests are carried out, and the influence of the wake model upon performance is studied. Predicted performance is shown to correlate well with the experiments.

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Salient Video Frames Sampling Method Using the Mean of Deep Features for Efficient Model Training (효율적인 모델 학습을 위한 심층 특징의 평균값을 활용한 의미 있는 비디오 프레임 추출 기법)

  • Yoon, Hyeok;Kim, Young-Gi;Han, Ji-Hyeong
    • Proceedings of the Korean Society of Broadcast Engineers Conference
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    • 2021.06a
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    • pp.318-321
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    • 2021
  • 최근 정보통신의 발달과 함께 인터넷에 접속하는 사용자 수와 그에 따른 비디오 데이터의 전송량이 늘어나는 추세이다. 이렇게 늘어나는 많은 비디오 데이터를 관리하고 분석하기 위해서 최근에는 딥 러닝 기법을 많이 활용하게 된다. 일반적으로 비디오 데이터에 딥 러닝 모델을 학습할 때 컴퓨터 자원의 한계로 인해 전체 비디오 프레임에서 균등한 간격 또는 무작위로 프레임을 선택하는 방법을 많이 사용한다. 하지만 학습에 사용되는 비디오 데이터는 항상 시간 축에 따라 같은 문맥을 담고 있는 Trimmed 비디오라고 가정할 수가 없다. 만약 같지 않은 문맥을 지닌 Untrimmed 비디오에서 균등한 간격 또는 무작위로 프레임을 선택해서 사용하게 된다면 비디오의 범주와 관련이 없는 프레임이 샘플링 될 가능성이 있기 때문에 모델의 학습 및 최적화에 전혀 도움이 되지 않는다. 이를 해결하기 위해 우리는 각 비디오 프레임에서 심층 특징을 추출하여 평균값을 계산하고 이와 각 추출된 심층특징들과 코사인 유사도를 계산해서 얻은 유사도 점수를 바탕으로 Untrimmed 비디오에서 의미 있는 비디오 프레임을 추출하는 기법을 제안한다. 그리고 Untrimmed 비디오로 구성된 데이터셋으로 유명한 ActivityNet 데이터셋에 대해서 대표적인 2가지 프레임 샘플링 방식(균등한 간격, 무작위)과 비교하여 우리가 제안하는 기법이 Untrimmed 비디오에서 효과적으로 비디오의 범주에 해당하는 의미 있는 프레임 추출이 가능함을 보일 것이다. 우리가 실험에 사용한 코드는 https://github.com/titania7777/VideoFrameSampler에서 확인할 수 있다.

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