• Journal of Information Processing Systems
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• 제15권2호
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• pp.344-358
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• 2019

Surveillance cameras have installed in many places because security and safety is becoming important in modern society. Through surveillance cameras installed, we can deal with troubles and prevent accidents. However, watching surveillance videos and judging the accidental situations is very labor-intensive. So now, the need for research to analyze surveillance videos is growing. This study proposes an algorithm to track multiple persons using SURF and background subtraction. While the SURF algorithm, as a person-tracking algorithm, is robust to scaling, rotating and different viewpoints, SURF makes tracking errors with sudden changes in videos. To resolve such tracking errors, we combined SURF with a background subtraction algorithm and showed that the proposed approach increased the tracking accuracy. In addition, the background subtraction algorithm can detect persons in videos, and SURF can initialize tracking targets with these detected persons, and thus the proposed algorithm can automatically detect the enter/exit of persons.

• Current Optics and Photonics
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• 제5권5호
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• pp.524-531
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• 2021

In an integral-imaging microscopy (IIM) system, a microlens array (MLA) is the primary optical element; however, surface errors impede the resolution of a raw image's details. Calibration is a major concern with regard to incorrect projection of the light rays. A ray-tracing-based calibration method for an IIM camera is proposed, to address four errors: MLA decentering, rotational, translational, and subimage-scaling errors. All of these parameters are evaluated using the reference image obtained from the ray-traced white image. The areas and center points of the microlens are estimated using an "8-connected" and a "center-of-gravity" method respectively. The proposed approach significantly improves the rectified-image quality and nonlinear image brightness for an IIM system. Numerical and optical experiments on multiple real objects demonstrate the robustness and effectiveness of our proposed method, which achieves on average a 35% improvement in brightness for an IIM raw image.

• 전력전자학회논문지
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• 제12권1호
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• pp.65-73
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• 2007

본 논문은 1-Hz의 낮은 고정자 전류 주파수에서도 동작하는 순수적분 기반의 자속추정을 위한 온라인 전류측정 오차 보상방법을 제안한다. 오프셋 전류와 변환이득오차에 의한 역상분 전류 성분은 상태관측기를 이용하여 제거하고, 동시에 변환이득오차에 의한 역상분 전류는 동기좌표계에서 영구자석에 의하여 발생된 q축 자속을 기준모델에 의한 값과 추정된 자속에 의한 값 사이의 차이에 의하여 보상한다. 이 보상기는 PI제어기를 이용하여 두 값 사이의 오차가 0이 되도록 제어한다. 또한 적분기 초기값 오차 및 관측기의 전동기 상수 오차에 의한 잔여오차 보상방법도 제안하였다. 타당성을 입증하기 위하여 1.1-kW 영구자석형 동기전동기(PMSM)에 제안된 보상 방법을 구현하여 다양한 실험을 수행하였다.

• 한국멀티미디어학회논문지
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• 제4권3호
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• pp.215-221
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• 2001

본 논문에서는 사이즈 펑션을 이용하여 윤곽선으로 표현된 물체의 특징을 추출할 때 발생하는 에러를 줄이기 위해 방향에 따라 가중값을 달리하는 새로운 표본화 알고리즘을 제안했다. 특히 회전, 이동, 크기 변환과 같은 변환에 대해서 불변성을 갖도록 설계했다. 특징값은 물체의 윤곽선을 사이즈 펑션 처리를 통해서 만들어진 행렬이고 이들간의 거리를 측정 비교함으로써 본 논문에서 제안한 방법이 효과적임을 보였다. 실험 결과 기존의 표본화 방법보다 제안한 표본화 방법을 사용했을 때 원본과 변형된 이미지 사이의 유클리디언 거리가 회전에 대해서 약 57% 크기변형에 대해서는 약 91% 개선되었다.

• 제어로봇시스템학회논문지
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• 제20권1호
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• pp.12-17
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• 2014

In this paper, we propose a controller capable of reducing the effect of measurement errors under AC and DC noise. Typically, the control system measures data through a sensor. If sensor noise is included in a controller via the feedback channel, the signal is distorted and the entire system cannot work normally. Therefore, some appropriate action to counter the measurement error effect is essential in the controller design. Our controller is equipped with a gain-scaling factor and a compensator to reduce the effect of measurement error in the feedback signal. Also, we use a switching control strategy to enhance the performance of the controller regarding convergence speed. Our proposed controller can therefore effectively reduce the AC and DC noise of the sensor. We analyze the proposed controller by Laplace transform technique and our control method is verified via MATLAB simulation.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2018년도 학술발표회
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• pp.150-150
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• 2018

The Numerical Weather Prediction (NWP) models provide information for weather forecasts. The highly nonlinear and complex interactions in the atmosphere are simplified in meteorological models through approximations and parameterization. Therefore, the simplifications may lead to biases and errors in model results. Although the models have improved over time, the biased outputs of these models are still a matter of concern in meteorological and hydrological studies. Thus, bias removal is an essential step prior to using outputs of atmospheric models. The main idea of statistical bias correction methods is to develop a statistical relationship between modeled and observed variables over the same historical period. The Model Output Statistics (MOS) would be desirable to better match the real time forecast data with observation records. Statistical post-processing methods relate model outputs to the observed values at the sites of interest. In this study three methods are used to remove the possible biases of the real-time outputs of the Weather Research and Forecast (WRF) model in Imjin basin (North and South Korea). The post-processing techniques include the Linear Regression (LR), Linear Scaling (LS) and Power Scaling (PS) methods. The MOS techniques used in this study include three main steps: preprocessing of the historical data in training set, development of the equations, and application of the equations for the validation set. The expected results show the accuracy improvement of the real-time forecast data before and after bias correction. The comparison of the different methods will clarify the best method for the purpose of the forecast skill enhancement in a real-time case study.

• 치위생과학회지
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• 제19권3호
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• pp.190-197
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• 2019

Background: The Internet has advantages in terms of accessibility and amount of information, and the search for health information over the Internet is increasing exponentially. The purpose of this study is to analyze the information generated about some dental treatment on the internet by year. Methods: Naver Knowledge (JisikIn in Korean) which is an interactive search service was selected as the first search site in Korea. Scaling, wisdom tooth extraction, and endodontic treatment that can be paid by Korean health insurance were selected. Finally, 4,729 questions about scaling, 23,963 wisdom teeth extraction questions and 17,733 endodontic treatment questions were extracted. The question contents, the information about the questioner and the answerer, and an error of answers were investigated. Frequency analysis was used and chi-square test was used if necessary. Results: The most frequently asked questions were discomfort and dissatisfaction after the treatment. The need for treatment was the second in questions of the wisdom tooth extraction and endodontic treatment, but the health insurance benefit was the second in dental scaling. Most of the questioners didn't disclose personal information. The public answered the most in 2013~2014, but the highest percentage of the respondents was experts in 2017. Responses were mostly personal experience, but showed a tendency to decrease with years, and professional knowledge showed an increasing tendency. The error of the answer has also gradually decreased. Conclusion: Questions about dental care over the Internet are increasing exponentially, experts are responding increasingly, and errors in answers are decreasing. Nevertheless, it is necessary to pay attention to the related expert group to prevent misinformation.

• Nuclear Engineering and Technology
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• 제38권1호
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• pp.11-32
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• 2006

System thermal-hydraulic codes have been used in the past decades in the areas of design, operation, licensing and safety of Nuclear Power Plants (NPPs). The development and validation of these codes have reached a high degree of maturity, through the consideration of huge experiments and advanced numerical models. Nowadays, the analyses are based upon realistic approaches rather than the conservative evaluation models. However the applications of these computational tools require preliminary qualification issues. Although huge amounts of financial and human resources have been invested for the development and improvement of codes, the calculation results are still affected by errors. In the sophisticated nuclear technology, design and safety of NPP, these errors must be quantified. An overview of the state of the art of the current thermal-hydraulic system code is developed and the need of uncertainty analysis in code calculations is emphasized. Several sources of uncertainty have been classified and commented, and typical applications of such methods are shown.

• 한국인터넷방송통신학회논문지
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• 제14권1호
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• pp.15-21
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• 2014

반도체 공정 기술의 발달로 인하여 프로세서 내에 적재할 수 있는 캐쉬 메모리의 용량은 증가하였지만 높은 트랜지스터 집적율은 프로세서를 소프트 에러에 대해 더 취약하게 만들었으며, 이는 설계 고려사항 중 신뢰성의 비중이 점점 더 높아짐을 의미한다. 이러한 취약성을 극복하기 위하여 캐쉬 메모리의 데이터에 대한 다양한 신뢰성 기법이 제안되었으나, 태그 비트에 대한 연구는 제한적이다. 본 연구는 캐쉬 메모리 중 태그 비트에 대해 Temporal Locality 특성을 만족하지 않는 write-back 동작에 대한 보호율을 분석하고, 이를 극복할 수 있는 방안을 제안한다. 실험을 통해 제안된 기법으로 기존의 write-back에 대한 보호율을 59.0%에서 76.8%까지 성능 저하 없이 증가시킬 수 있다.

• Journal of Microbiology and Biotechnology
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• 제23권5호
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• pp.689-698
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• 2013

The production and characterization of an active recombinant N-acetylgalactosamine-6-sulfate sulfatase (GALNS) in Escherichia coli BL21(DE3) has been previously reported. In this study, the effect of the signal peptide (SP), inducer concentration, process scale, and operational mode (batch and semi-continuous) on GALNS production were evaluated. When native SP was presented, higher enzyme activity levels were observed in both soluble and inclusion bodies fractions, and its removal had a significant impact on enzyme activation. At shake scale, the optimal IPTG concentrations were 0.5 and 1.5 mM for the strains with and without SP, respectively, whereas at bench scale, the highest enzyme activities were observed with 1.5 mM IPTG for both strains. Noteworthy, enzyme activity in the culture media was only detected when SP was presented and the culture was carried out under semi-continuous mode. We showed for the first time that the mechanism that in prokaryotes recognizes the SP to mediate sulfatase activation can also recognize a eukaryotic SP, favoring the activation of the enzyme, and could also favor the secretion of the recombinant protein. These results offer significant information for scaling-up the production of human sulfatases in E. coli.