• 한국안전학회지
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• 제22권2호
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• pp.53-58
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• 2007

This study is to find out primary factors through the punch list in the large scale apartment housing complex, to prevent repeatedly occurring defects of construction and to gain quality management. The following are the findings of the research. (1) The positive strengthening of supervision for the workers can contribute to prevent defects of apartment construction and make better quality of the construction. (2) A solution should be made for the poor of surface join and the damage of work element showing a lot in the apart construction, which prevent defects and improve construction quality. (3) Indirect factors such as negligence and carelessness of the management should be improved to advance construction quality, and the caution and control strengthening of the management should be followed. It is revealed that hitch, omission, and heedlessness come from the defects, and the shortage of skill and checking appear as indirect factors. Therefore, to get quality improvement, the enhancement of the management factors, employment of excellent workers, and enhancement of working attitude and construction management are needed.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2009년도 IWAIT
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• pp.294-297
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• 2009

Multi-view video consists of a set of multiple video sequences from multiple viewpoints or view directions in the same scene. It contains extremely a large amount of data and some extra information to be stored or transmitted to the user. This paper presents inter-view correlations among video objects and the background to reduce the prediction complexity while achieving a high coding efficiency in multi-view video coding. Our proposed algorism is based on object-based segmentation scheme that utilizes video object information obtained from the coded base view. This set of data help us to predict disparity vectors and motion vectors in enhancement views by employing object registration, which leads to high compression and low-complexity coding scheme for enhancement views. An experimental results show that the superiority can provide an improvement of PSNR gain 2.5.3 dB compared to the simulcast.

• 한국광학회지
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• 제6권3호
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• pp.228-232
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• 1995

초고속 광통신을 위한 고속변조용 단일모드 반도체 레이저로서 변조 도핑된 SMQW-PBH-DFB-LD를 제작하고 변조특성을 축정 하였다. 제작된 소자의 최소 임계전류는 16.0mA, 최대 slope efficiency는 0.275mW/mA였다. 고속변조를 위한 활성층의 변조도핑으로 소자의 내부손실은 $37cm^{-1}$로 크게 주어졌으나. 이득계수의 증가에 따라 선폭확대계수는 1.8로 감소되었다. 소신호 변조 특성 측정 결과, $46mA(I_{th}+30mA)$ 에서의 공진주파수 8GHz, -3dB 차단주파수 10GHz 이상으로서 고속변조 특성이 우수한 변조도핑된 SMQW-PBH-DFB-LD를 시험 제작하였다.

• 한국지능시스템학회논문지
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• 제20권4호
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• pp.522-527
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• 2010

본 논문은 유방 조영 영상의 대비를 향상시키기 위해 새로운 호모몰픽 필터(MBHF)를 제안한다. 제안된 필터는 영상을 형체적으로 다수 분할한 후 각각의 형체 즉, 서브-밴드에 대해 그 구성요소와 이득이 차분진화를 통해 최적의 값을 갖도록 설계된다. 결과 분석을 통해 제안된 방법이 영상 대비를 향상시키는 것을 보이며 웨이블렛 기반의 호모몰픽 필터와 성능이 비교된다. 성능평가 기준으로는 인간의 시각적 인식을 고려한 WPSNR(Weighted Peak Signal to Noise Ratio)을 사용한다.

• 마이크로전자및패키징학회지
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• 제26권2호
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• pp.55-58
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• 2019

최근 표면 플라즈몬 효과는 광 신호 향상에 중요하게 대두되고 있는 분야로써, 약한 광학적 신호를 증가시킴에 따라 바이오 분야나 뉴로사이언스에 매우 중요한 분야로 대두되었다. 플라즈모닉 구조를 제작하기 위해선 나노 구조의 크기 높이 그리고 입사광의 입사각 등 다양한 변수들이 존재하는데 본 논문에서는 플라즈모닉 나노구조의 제작을 위한 은 증착 높이에 따른 플라즈모닉 나노구조의 광학적 특성에 대한 연구를 진행하였다. 은 증착은 플라즈모닉 효과를 보기 위해 다양하게 사용하고 있는 금속으로 특정 파장에 반응을 보기 위해 제작한 구조 형태와 유사한 구조를 시간영역 유한차분(FDTD)법을 통해 광 특성을 예측하여, 최종적으로 제작한 구조의 은 나노 입자 부근에 에너지가 집중되는 결과를 확인하였다.

• 산경연구논집
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• 제12권9호
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• pp.19-29
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• 2021

Purpose: To thrive a competitive advantage in the highly competitive global market, a company must establish a strong startup culture, which creates a workplace environment that values innovation and creativity in solving business-related problems. This study investigates the importance of enhancing startup culture in a competitive environment to improve organizational performance, production and hence produce higher returns. Research design, data and methodology: We conducted the qualitative content analysis and its steps seek to ensure that the researcher adheres to a systematic analysis of the data. The method is used for subjective examination of content in any text data and the five steps minimize cases of errors or repetition in used content. Results: Our investigation based on previous literature resources indicates that leading strategies and creating a pleasant working environment are vital behaviors that companies should consider adopting and implementing to achieve a beneficial startup culture full of productivity and massive returns. Conclusion: This research aimed to discuss the necessity of startup culture's enhancement for for-profit companies and found that the adoption of a startup culture in a company is critical to its success. It is vital to building a solid startup culture to grow and gain a competitive advantage in the highly competitive business world.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2015년도 추계학술대회
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• pp.451-454
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• 2015

본 논문에서는 저전압, 저전력 회로에 적합하고, $0.35{\mu}m$ 공정을 이용한 3가지의 OTA를 제시한다. 첫 번째는 1V의 공급전압과 $1.774{\mu}W$의 소비전력을 사용하며 모든 트랜지스터들이 strong inversion 영역에서 동작한다. Bulk 입력으로 인해 줄어든 gm을 보상하기 위해서 Gm-enhancement 기법을 사용하였고, 저전압으로 동작하는 Wide swing current mirror, Class-A output을 적용하였다. 두 번째는 0.8V의 공급전압과 52nW의 소비전력을 사용하여 112dB의 높은 이득을 가지는 2-stage OTA이다. Current mirror는 두 개의 MOS의 Gate를 묶는 Composite Transistor 구조를 사용하여 마치 Cascode와 같은 효과를 주어 출력저항을 높여주었다. 세 번째는 0.6V의 공급전압과 160nW의 소비전력을 사용하여 77dB의 이득을 가지는 2-stage OTA이다. 두 번째 증폭 단에 추가적인 바이어스전압이 필요하지 않으면서 증폭할 수 있도록 Common Gate 구조로 구현하여 Level Shift 기능을 사용하였다.

• 전기학회논문지
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• 제57권3호
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• pp.518-526
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• 2008

The fuzzy self-tuning PID controller is a PID controller with a fuzzy logic mechanism for tuning its gains on-line. In this structure, the proportional, integral and derivative gains are tuned on-line with respect to the change of the output of system under control. This paper deals with two types of fuzzy self-tuning PID controllers, rule-based fuzzy PID controller and learning fuzzy PID controller. As a medical application of fuzzy PID controller, the proposed controllers were implemented and evaluated in a laparoscopic surgery robot system. The proposed fuzzy PID structures maintain similar performance as conventional PID controller, and enhance the position tracking performance over wide range of varying input. For precise approximation, the fuzzy PID controller was realized using the linear reasoning method, a type of product-sum-gravity method. The proposed controllers were compared with conventional PID controller without fuzzy gain tuning and was proved to have better performance in the experiment.

• 동력기계공학회지
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• 제14권2호
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• pp.34-39
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• 2010

Recently, technical trend for machine tools is focused on enhancement of speed and accuracy. High speedy processing causes thermal and structural deformation of objects from the machine tools. Water cooler has to be applied to machine tools to reduce the thermal negative influence with accurate temperature controlling system. Existing On-Off control type can't control temperature accurately because compressor is operated and stopped repeatedly and causes increment of power consumption and decrement of the expected life of compressor. The goal of this study is to minimize temperature error in steady state. In addition, control period of an electronic expansion valve were considered to increment of lifetime of the machine tools and quality of product with a water cooler. PI controller is designed using type of hot-gas bypass for precise control of temperature. Gain of PI is decided easily by method of critical oscillation response, excellent performance of control is shown with 4.24% overshoot and ${\pm}0.2^{\circ}C$error of steady state. Also, error range of temperature is controlled within $0.2^{\circ}C$although disturbance occurs.

• 한국소음진동공학회논문집
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• 제21권5호
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• pp.447-454
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• 2011

This paper reports a filtered velocity feedback(FVF) controller, which is an alternative to direct velocity feedback(DVFB) controller. The instability problems due to high frequency response under DVFB can be alleviated by the suggested FVF controller. The FVF controller is designed to filter out the unstable high frequency response. The FVF controller and the dynamics of clamped beams under forces and moments are first formulated. The effects of the design parameters(cut-off frequency, gain, and damping ratio) on the stability and the performance are then investigated. The cut-off frequency should be selected not to affect the system stability. The magnitude of the open loop transfer function(OLTF) at the cut-off frequency should be small. As increasing the gain of the FVF controller, the magnitude of the OLTF is increased, so that the closed loop response can be reduced more. The enhancement of the OLTF at the cut-off frequency is reduced but the phase behavior around the cut-off frequency is distorted, as the damping ratio is increased. The control performance is finally estimated for the clamped beam. More than 10 dB reductions in velocity response can be achieved at the modal frequencies from the first to eighth modes.