• Journal of Information Display
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• 제11권1호
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• pp.21-23
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• 2010

A new level shifter using low-temperature polycrystalline silicon (poly-Si) thin-film transistors (TFTs) for low-power applications is proposed. The proposed level shifter uses a capacitive-coupling effect and can reduce the power consumption owing to its no-short-circuit current. Its power saving over the conventional level shifter is 72% for a 3.3 V input and a 10 V output.

• 공학교육연구
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• 제19권6호
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• pp.32-37
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• 2016

The purpose of this study is to extract a skill level of human resource in the field of science and technology. To accomplish the goal of this study, precedent research was conducted and then, the draft of skill level for Human Resource in the field of Science and Technology (HRST) was created by wrap-up meeting. The skill level of the HRST was finalized after confirming verification of 20 SMEs (Subject Matter Experts) from January to February 2016 by two times. The conclusions are as follows; First, the skill level of the HRST consists five categories. Each of the level has educational background, work experience, certification, duty, major and so on. Second, the contents of the skill level were found to be mostly valid.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제16권6호
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• pp.2044-2059
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• 2022

Recent works have shown that the geometric constraint can be harnessed to boost the performance of CNN-based camera localization. However, the existing strategies are limited to imposing image-level constraint between pose pairs, which is weak and coarse-gained. In this paper, we introduce a pixel-level epipolar geometry constraint to vanilla localization framework without the ground-truth 3D information. Dubbed EpiLoc, our method establishes the geometric relationship between pixels in different images by utilizing the epipolar geometry thus forcing the network to regress more accurate poses. We also propose a variant called EpiSingle to cope with non-sequential training images, which can construct the epipolar geometry constraint based on a single image in a self-supervised manner. Extensive experiments on the public indoor 7Scenes and outdoor RobotCar datasets show that the proposed pixel-level constraint is valuable, and helps our EpiLoc achieve state-of-the-art results in the end-to-end camera localization task.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.1025-1026
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• 2008

The level crossing collision accident which comprises more than 90 percent of all level crossing accidents is one of the most serious safety problems. There is a critical need for providing safe strategy and is focusing on the level crossing information rather than measures at a grade crossing. This study is intended to develop technology for accident prevention and damage reduction based on accident cases analysis result and improvement direction to complement shortcomings of safety equipment of conventional level crossing and to establish safety of travelers(train, motor vehicle, person).

• Journal of Power Electronics
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• 제18권2호
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• pp.407-417
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• 2018

A novel family of Buck mode three-level direct ac converters with a high frequency link is proposed. These converters can transfer an unsteady high ac voltage with distortion into a regulated sinusoidal voltage with a low THD at the same frequency. The circuit configuration is constituted of a three-level converter, high frequency transformer, cycloconverter, as well as input and output filters. The topological family includes forward, push-pull, half-bridge, and full-bridge modes. In order to achieve a reliable three-level ac-ac conversion, and to overcome the surge voltage and surge current of the cycloconverter, a phase-shifted control strategy is introduced in this paper. A prototype is presented with experimental results to demonstrate that the proposed converters have five advantages including high frequency electrical isolation, lower voltage stress of the power switches, bi-directional power flow, low THD of the output voltage, and a higher input power factor.

• Nuclear Engineering and Technology
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• 제48권1호
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• pp.98-113
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• 2016

A reactor vessel level monitoring system measures the water level in a reactor during normal operation and abnormal conditions. A drop in the water level can expose nuclear fuel, which may lead to fuel meltdown and radiation spread in accident conditions. A level monitoring system mainly consists of a sensing line and pressure transmitter. Over a period of time boron sediments or other impurities can clog the line which may degrade the accuracy of the monitoring system. The aim of this study is to determine blockage in a sensing line using the energy of the composite signal. An equivalent Pi circuit model is used to simulate blockages in the sensing line and the system's response is examined under different blockage levels. Composite signals obtained from the model and plant's unblocked and blocked channels are decomposed into six levels of details and approximations using a wavelet filter bank. The percentage of energy is calculated at each level for approximations. It is observed that the percentage of energy reduces as the blockage level in the sensing line increases. The results of the model and operational data are well correlated. Thus, in our opinion variation in the energy levels of approximations can be used as an index to determine the presence and degree of blockage in a sensing line.

• Journal of Power Electronics
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• 제14권5호
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• pp.937-945
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• 2014

This paper presents an optimized space vector pulse-width modulation (OSVPWM) technique for a five-level cascaded H-bridge (CHB) inverter. The space vector diagram of the five-level CHB inverter is optimized by resolving it into inner and outer two-level space vector hexagons. Unlike conventional space vector topology, the proposed technique significantly reduces the involved computational time and efforts without compromising the performance of the five-level CHB inverter. A further optimized (FOSVPWM) technique is also presented in this paper, which significantly reduces the complexity and computational efforts. The developed techniques are verified through MATLAB/SIMULINK. Results are compared with sinusoidal pulse-width modulation (SPWM) to prove the validity of the proposed technique. The proposed simulation system is realized by using an XC3S400 field-programmable gate array from Xilinx, Inc. The experiment results are then presented for verification.

• Ocean Systems Engineering
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• 제7권4호
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• pp.319-328
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• 2017

Higher prediction efficacy is a very challenging task in any field of engineering. Due to global warming, there is a considerable increase in the global sea level. Through this work, an attempt has been made to find the sea level variability due to climate change impact at Haldia Port, India. Different statistical downscaling techniques are available and through this paper authors are intending to compare and illustrate the performances of three regression models. The models: Wavelet Neural Network (WNN), Minimax Probability Machine Regression (MPMR), Feed-Forward Neural Network (FFNN) are used for projecting the sea level variability due to climate change at Haldia Port, India. Model performance indices like PI, RMSE, NSE, MAPE, RSR etc were evaluated to get a clear picture on the model accuracy. All the indices are pointing towards the outperformance of WNN in projecting the sea level variability. The findings suggest a strong recommendation for ensembled models especially wavelet decomposed neural network to improve projecting efficiency in any time series modeling.

• 기술혁신학회지
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• 제10권4호
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• pp.654-686
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• 2007

과학기술 수준을 정확히 측정 분석하기 위해서는 우리 기술수준과 비교대상의 위치, 그리고 해당 기술의 이론적인 상한 수준을 우선 전제해야만 한다. 그리고 각각의 기술변화 정도를 파악하는 것이 추가적으로 필요하다. 우리나라 및 비교대상에 대한 동태적 측면이 고려되어 현재의 위치와 함께 과정과 경로도 중요시 되어야 한다. 이를 위해서 이 연구는 기술발전 단계와 성장곡선 개념을 활용하는 방안을 제시한다. 이론적 및 가상적 사례 적용 결과, 우리나라 기술수준의 향상은 뚜렷하게 보이고 있으나 같은 기간에 지속적으로 변화하고 있는 세계최고기술 수준과는 여전히 격차가 존재하는 것으로 추정된다. 추정 결과가 사실이라고 가정할 경우, 우리나라 기술의 실질적인 추격의 가능성은 그리 크지 않은 것으로 보인다. 특히, 바이오신약 장기 분야와 지능형로봇 분야의 경우에는 세계최고기술 수준과의 격차기간이 더욱 벌어지고 있는 것으로 추정되어 해당 분야에 대한 실질적이고, 심층적인 검토 및 분석이 시급히 요구된다. 이 연구는 기술수준 측정과 분석을 성장곡선 유형의 추정을 통해 위상분석과 변화과정을 파악하여 궁극적인 추격의 가능성을 제시한다. 이론적 타당성과 현실적 적용성에 대한 검증을 위해 향후 구체적인 사례분석이 필요하다.

• 한국의류학회지
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• 제36권3호
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• pp.269-281
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• 2012

This study investigates the influence of technology readiness, fashion innovativeness, and participation level perception on the acceptance intention of 3D virtual fitting systems. We presented a 3D virtual fitting system with detailed information that was watched by respondents who subsequently completed a research questionnaire. The data were collected from 300 subjects with an age range of 21 to 39 who have experienced Internet shopping. Descriptive statistics, Cronbach's alpha, factor analysis, correlation analysis, and multiple regression analysis were conducted. The results were as follows. First, fashion innovativeness, technology innovativeness, participation level perception, and optimism significantly influenced the acceptance intention. Second, fashion innovativeness, technology innovativeness, participation level perception, and optimism positively influenced the acceptance intention in the male group; however, technology innovativeness, participation level perception, optimism, and insecurity significantly influenced the acceptance intention in the female group. The results indicated that a marketing strategy has to be designed that focuses on consumers with high technology, fashion innovativeness, and optimism to increase the acceptance intention. In addition, markers have to enhance a participation level perception that will contribute to the introduction of 3D virtual fitting systems. Another notable finding was the importance to differentiate marketing strategies according to gender.