• 재활복지공학회논문지
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• 제4권1호
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• pp.43-51
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• 2010

본 논문에서는 사용자의 훈련효과 향상을 위한 세계공인 전자호구 시스템에 기반한 디지털 태권도 트레이너 시스템을 개발하였다. 본 시스템은 전자호구용 모듈을 확장한 타격감지 모듈과 타격목표 지정을 위한 LED 인디케이터를 포함한 E-Kick Bag, 훈련 설정 및 훈련 관련 제어와 사용자의 훈련정보 및 통계 등을 분석하는 태권도 트레이너 프로그램, 그리고 E-Kick Bag과 트레이너 프로그램을 유/무선으로 연결하는 수신기로 구성된다. 태권도 트레이너 시스템은 사용자에게 6개의 LED 인디케이터를 이용하여 타격목표를 지정해 줌으로써 타격정확도 및 반응속도 등의 운동기능 및 훈련효과를 향상시키는 장점을 가진다. 트레이너 시스템은 또한 훈련결과로부터 사용자의 타격강도 및 정확도 분석을 통한 타격 패턴 및 장/단점을 파악하여 제공할 수 있다는 특징을 가진다. 본 논문에서는 시스템의 효율성을 판단하기 위해 국가대표선수를 포함한 다양한 체급, 나이, 성별의 선수 8명을 대상으로 임상 실전 평가를 실시하였고, 시스템의 만족도 및 가치를 설문조사하였다.

• Computers and Concrete
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• 제20권4호
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• pp.391-407
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• 2017

Fiber reinforced polymer (FRP) bars have been recently used to reinforce concrete members in flexure due to their high tensile strength and especially in corrosive environments to improve the durability of concrete structures. However, FRPs have a low modulus of elasticity and a linear elastic behavior up to rupture, thus reinforced concrete (RC) components with such materials would exhibit a less ductility in comparison with steel reinforcement at the similar members. There were several studies showed the behavior of concrete beams with the hybrid combination of steel and FRP longitudinal reinforcement by adopting the experimental and numerical programs. The current study presents a numerical and analytical investigation based on the data of previous researches. Three-dimensional (3D) finite element (FE) models of beams by using ANSYS are built and investigated. In addition, this study also discusses on the design methods for hybrid FRP-steel beams in terms of ultimate moment capacity, load-deflection response, crack width, and ductility. The effects of the reinforcement ratio, concrete compressive strength, arrangement of reinforcement, and the length of FRP bars on the mechanical performance of hybrid beams are considered as a parametric study by means of FE method. The results obtained from this study are compared and verified with the experimental and numerical data of the literature. This study provides insight into the mechanical performances of hybrid FRP-steel RC beams, builds the reliable FE models which can be used to predict the structural behavior of hybrid RC beams, offers a rational design method together with an useful database to evaluate the ductility for concrete beams with the combination of FRP and steel reinforcement, and motivates the further development in the future research by applying parametric study.

• Journal of Biosystems Engineering
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• 제26권5호
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• pp.423-430
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• 2001

The purpose of this study is to develop high-speed rotary tillage system for a power tiller by improving the rotary blade and the power train of transmission. Mechanical structure of gear train of rotary drive of conventional power tiller was simplified so that power can be transmitted directly from second shaft to tilling speed change shaft by rotating freely the transfer gear which changes the direction of rotation of shafts using needle bearing installed into middle shaft. A new gear train suitable for the single-edged rotary blade and high-speed rotary drive was developed with the rotational speed of rotary shaft faster than 7.5% at 1st-speed and 1.4% at 2nd-speed the one of conventional system by changing the numbers of teeth of gears of middle shaft, tilling speed change shaft and PTO shaft. Using the developed gear train for high-speed rotary drive, field tests were performed to compare tillage performances by the developed single-edged blade and by the conventional double-edged blade. The results showed that the performances by the single-edged blade compared with the one by the double-edged blade was improved about 18% in field capacity, about 34% in fuel consumption, and 9.4% in soil crushing ratio. Therefore, it may be concluded that tillage performance by the single-edged blade was improved compared to the one by the conventional blade. Evaluation of the developed system consisting of single-edged blade and gear train for high-speed rotary drive in field revealed that tillage performance of the developed system was similar to the one of field test conducted using the system consisting of single-edged blade and gear train for rotary drive of conventional power tiller However, considering the higher cone index of the upland field where evaluation was carried out compare to the one of the ordinary paddy field, it may be concluded that tillage performance of the developed rotary tilling system better than the one of conventional system.

• 한국군사과학기술학회지
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• 제17권1호
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• pp.90-95
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• 2014

The system design and the system performance analysis of 3D imaging laser radar system for the mapping purpose is addressed in this article. For the mapping, a push-bloom scanning method is utilized. The pulsed fiber laser with high pulse energy and high pulse repetition rate is used for the light source of laser radar system. The high sensitive linear mode InGaAs avalanche photo-diode is used for the laser receiver module. The time-of-flight of laser pulse from the laser to the receiver is calculated by using high speed FPGA based signal processing board. To reduce the walk error of laser pulse regardless of the intensity differences between pulses, the time of flight is measured from peak to peak of laser pulses. To get 3D image with a single pixel detector, Risley scanner which stirs the laser beam in an ellipsoidal pattern is used. The system laser energy budget characteristics is modeled using LADAR equation, from which the system performances such as the pulse detection probability, false alarm and etc. are analyzed and predicted. The test results of the system performances are acquired and compared with the predicted system performance. According to test results, all the system requirements are satisfied. The 3D image which was acquired by using the laser radar system is also presented in this article.

• 대한원격탐사학회지
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• 제25권2호
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• pp.133-143
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• 2009

이 논문은 엄격한 물리적 센서 모델인 궤도 자세각 모델이 위성체의 자세제어 방식이 다른 두 위성 영상에 적용한 경우 나타나는 성능의 차이를 기술한다. 영상 취득 시 Spot 위성은 거울 회전(mirror-tilt) 방식을 채택하고 있으며 Kompsat-2 위성은 몸통 회전(body-tilt) 방식을 채택하고 있다. 이 논문은 선행 연구에서 이미 우수한 성능이 검증된 궤도 자세각 모델로 연구의 범위를 제한하며 미지수 조합에 따른 센서 모델 정확도 및 3차원 좌표 산출 정확도를 통해 두 영상에서 나타나는 모델 성능의 차이를 비교한다. 실험 결과는 동일한 궤도 자세각 모델이 두 영상에 대해 다른 성능이 나타남을 보여주고 있으며 Spot 위성의 경우에는 자세 각 미지수가 포함된 모델을, Kompsat-2 영상의 경우에는 많은 개수의 미지수를 갖는 모델을 사용하는 것이 효율적임을 제안한다. 이는 동일한 모델이라 하더라도 센서의 영상 취득 방식과 그로 인한 자세 추정의 정확도에 따라 다르게 적용되는 것이 효과적일 수 있음을 나타낸다. 이러한 차이를 이해하는 것은 향후 모델 정확도 개선과 새로운 영상에 대한 모델 적용을 위한 중요한 토대가 될 것이다.

• 한국해양공학회지
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• 제33권1호
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• pp.68-75
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• 2019

A low-crested structure (LCS) is an excellent feature not only because it provides shore protection but also because it is fully submerged. However, in order to properly control waves, it is necessary to maintain a certain range of crest height and width in consideration of the wave dimensions at the installation area. According to previous studies, an LCS has some wave breaking effect when the crest width is more than a fourth of the incident wavelength and the crest depth is less than a third of the incident wave height. In other words, if the crest width of the LCS is small or the crest depth is large, it cannot control the wave. Therefore, when an LCS is installed in a large sea area with a great tidal range in consideration of the landscape, waves cannot be blocked at high tide. In this study, the hydraulic performances of a typical trapezoidal LCS with a constant crest height and a low-crested structure with an adjustable crest height, which was called a tide-adapting low-crested structure (TA-LCS) in this study, were compared and evaluated under various wave conditions through hydraulic experiments. It was found that the wave transmission coefficients of the TA-LCS at high tide were lower than the values for the typical LCS based on empirical formulas. In addition, the hydraulic performances of the TA-LCS for wave reflection control were 12.9?30.4% lower than that of the typical LCS. Therefore, the TA-LCS is expected to be highly effective in controlling the energy of incoming waves during high tide even in a macro-tidal area.

• 한국멀티미디어학회논문지
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• 제25권10호
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• pp.1375-1385
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• 2022

In this paper, we propose a semi-supervised domain adaptation solution to deal with practical face recognition (FR) scenarios where a single face image for each target identity (to be recognized) is only available in the training phase. Main goal of the proposed method is to reduce the discrepancy between the target and the source domain face images, which ultimately improves FR performances. The proposed method is based on the Domain Adatation network (DAN) using an MMD loss function to reduce the discrepancy between domains. In order to train more effectively, we develop a novel loss function learning strategy in which MMD loss and cross-entropy loss functions are adopted by using different weights according to the progress of each epoch during the learning. The proposed weight adoptation focuses on the training of the source domain in the initial learning phase to learn facial feature information such as eyes, nose, and mouth. After the initial learning is completed, the resulting feature information is used to training a deep network using the target domain images. To evaluate the effectiveness of the proposed method, FR performances were evaluated with pretrained model trained only with CASIA-webface (source images) and fine-tuned model trained only with FERET's gallery (target images) under the same FR scenarios. The experimental results showed that the proposed semi-supervised domain adaptation can be improved by 24.78% compared to the pre-trained model and 28.42% compared to the fine-tuned model. In addition, the proposed method outperformed other state-of-the-arts domain adaptation approaches by 9.41%.

• 중소기업연구
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• 제43권3호
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• pp.21-42
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• 2021

소기업의 성장과 경쟁력 강화를 위한 연구개발(R&D) 활동이 점점 중요해지고 있으며, 정부의 R&D 지원금도 증가하고 있다. 본 연구는 소기업의 R&D 성과를 제고하기 위해, 자원기반론적 관점에서 소기업의 R&D 성과에 영향을 미치는 요인과 필요한 역량을 파악하였다. 정부 R&D 지원사업에 참여하여 R&D 프로젝트를 완료한 소기업 3,636개사를 대상으로 설문 조사를 수행하였으며, 다중회귀분석을 실시하였다. 소기업의 기술혁신역량과 기술사업화역량은 조직 역량에 유의한 정(+)의 영향을 미치며, 그 관계를 기업가정신이 조절하는 것으로 나타났다. 또한 소기업의 R&D 역량은 R&D 사업화 성과에 직접 유의한 영향을 미치는 것이 아니라, 조직역량을 매개로 R&D성과에 유의한 영향을 미치는 것으로 분석되었다. 본 연구는 소기업 R&D의 성과 분석을 위한 중간 단계의 변수인 조직역량의 중요성을 포함해, 소기업 R&D 성과 측정 및 지원 정책에 대한 시사점을 제시한다.

• Journal of Korea Trade
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• 제27권3호
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• pp.65-86
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• 2023

Purpose - As globalization progresses, complexity also increases, and various factors that threaten port functions are emerging. Accordingly, the demand for port security to prevent the crisis and resilience that quickly recovers its original function after the crisis is also increasing in port operations. However, few studies have examined how to ensure the port security and how the resilience affects operation performance of port and sustainability performance as well. So the study aims to find out how port security affects port resilience and port operational performance, and consequently, this two factors affect socioeconomic and environmental sustainability performance respectively and synthetically. Design/methodology - Confirmatory Factor Analysis (CFA) was first performed to determine the validity of the factors of model and hypothesis test was performed using Structural Equation Model (SEM) to analyze the Port Performance Model, which show the perception logic among port security level, port resilience, operation performance, and sustainability performance. In order to empirically analyze this model, total 264 respondents from port security operators, shipping companies in South Korea were surveyed. Findings - As result of SEM, First, port security level positively affected the resilience (H1) and cargo operational performance (H2) but not in both of the sustainability performances (H3, H4). Second, resilience positively affected only cargo operational performance (H5) and socio-economic sustainability performance (H7). Last, cargo operation performance positively affects the both of sustainability performances (H8, H9). Originality/value - It was confirmed that port security could improve cargo operational performance through ensuring port resilience and eventually increase the socio-economic sustainability. Therefore the study implies that careful integration and management of port security, port resilience, and sustainability are required, along with compromise on sustainable development goals in the social, economic, and environmental area among all stakeholders.

• 한국실천공학교육학회논문지
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• 제2권2호
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• pp.120-136
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• 2010

최근 평생학습 중요성 증가에 따라 평생교육기관 수 및 평생교육 프로그램에 참가하는 학습자 수가 크게 증가하고 있으며 여러 유형의 평생교육기관 중 가장 학습 받기를 원하는 기관으로 대학 평생교육기관으로 조사되고 있다. 이에 본 연구에서는 대학 평생교육기관의 지속성장과 경쟁우위 확보방안에 공헌하기 위하여 대학 평생교육 기관의 성과에 영향을 미치는 요인을 규명하고자 자원기반관점이론과 동태적역량이론에 기반하여 전국 대학 평생교육기관 관리자인 팀장급과 학습자와 가장 근접해 상호작용이 활발한 교 강사를 대상으로 조사 분석하였다. 본 연구내용 및 결과는 첫째, 대학 평생교육대학의 자원과 성과의 관계를 규명하고자 하였다. 그 분석결과 대학 평생 교육기관의 물적자원인 접근편의성, 시설우수성, 인적자원인 교 강사의 우수성은 성과에 정(+)영향을 미치는 것으로 분석되었다. 둘째, 대학 평생교육기관의 동태적역량에 영향을 미치는 선행요인을 파악하고자 하였다. 그 연구결과 접근편의성, 시설 우수성,교 강사 우수성 등 물적, 인적자원과 상사인 원장의 임파워링리더십, 조직분위기(자율성,상호작용)는 동태적역량에 정(+)영향을 미치는 것으로 나타났다. 이 분석결과는 대학 평생교육기관 특성이 반영된 결과로 해석 할 수 있다. 셋째, 조직의 발전을 위해서는 자원기반관점에 기반한 자원도 중요한 요소지만 대학 평생교육기관의 지속적인 성장과 발전을 위해서는 조직의 역량인 동태적역량이 더욱 중요함을 규명하고자 하였다. 그 연구결과 동태적역량인 흡수역량과 혁신역량은 자원과 성과의 관계에서 매개효과가 있는 것으로 분석되었으며, 마찬가지로 흡수역량, 혁신역량은 상사의 임파워링리더십, 조직분위기(자율성,상호작용)와 성과의 관계에서도 매개효과가 있는 것으로 나타났다. 이는 자원의 우수성은 대학 평생교육기관을 어느 수준까지 발전시키는데까지는 기여 할 수 있지만 급격히 변화하는 평생교육시장의 동적환경하에서 지속적인 성장과 발전을 위해서는 조직의 동태적역량이 더욱 중요함을 시사하고 있다.