• 전기학회논문지
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• 제57권12호
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• pp.2291-2299
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• 2008

Hall effect force sensors have been used to measure clamping force in conventional Electric Parking Brake(EPB) systems. Estimation of clamping force without the sensors has drawn attentions due to mounting space limitations and cost issues. Removing the sensor requires the estimation of the initial contact point where the clamping force is effectively applied to the brake pads. In this paper, we propose how to estimate the initial contact point finding the relation between the angular velocity of an actuator and the initial contact point. For force estimation a look-up table is used as a function of the displacement of parking cable from the initial contact point. The proposed method is validated by experiments. From the experimental results we observe that the proposed method satisfies the specifications. The designed method is also able to estimate clamping force although parking cables are loosened and brake pads are worn out. Applying the proposed method enables manufacturing of low cost EPB systems.

• 제어로봇시스템학회논문지
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• 제22권6호
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• pp.403-410
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• 2016

This paper proposes a robust image-based visual servoing scheme using a nonlinear observer for a monocular eye-in-hand manipulator. The proposed control method is divided into a range estimation phase and a target-tracking phase. In the range estimation phase, the range from the camera to the target is estimated under the non-moving target condition to solve the uncertainty of an interaction matrix. Then, in the target-tracking phase, the feature point uncertainty caused by the unknown motion of the target is estimated and feature point errors converge sufficiently near to zero through compensation for the feature point uncertainty.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 심포지엄 논문집 정보 및 제어부문
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• pp.26-28
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• 2007

The motion estimation is the most important technique in the image compression of the video standards. In the case of next generation standards in the video codec as H.264, a high compression-efficiency can be also obtained by using a motion compensation. To obtain the accurate motion search, a motion estimation should be achieved up to 1/2 pixel and 1/4 pixel uiuts. To do this, the computational complexity is increased although the image compression rate is increased. Therefore, in this paper, we propose the advanced sub-pixel block matching algorithm to reduce the computational complexity by using a statistical characteristics of SAD(Sum of Absolute Difference). Generally, the probability of the minimum SAD values is high when searching point is in the distance 1 from the reference point. Thus, we reduced the searching area and then we can overcome the computational complexity problem. The main concept of proposed algorithm, which based on TSS(Three Step Search) method, first we find three minimum SAD points which is in integer distance unit, and then, in second step, the optimal point is in 1/2 pixel unit either between the most minimum SAD value point and the second minimum SAD point or between the most minimum SAD value point and the third minimum SAD point In third step, after finding the smallest SAD value between two SAD values on 1/2 pixel unit, the final optimized point is between the most minimum SAD value and the result value of the third step, in 1/2 pixel unit i.e., 1/4 pixel unit in totally. The conventional TSS method needs an eight.. search points in the sub-pixel steps in 1/2 pixel unit and also an eight search points in 1/4 pixel, to detect the optimal point. However, in proposed algorithm, only total five search points are needed. In the result. 23 % improvement of processing speed is obtained.

• The Journal of the Acoustical Society of Korea
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• 제20권3E호
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• pp.25-30
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• 2001

In angle of arrival estimation, the direction of a signal is usually assumed to be a point. If the direction of a signal is distributed due to some reasons in real surroundings, however, angle of arrival estimation techniques based on the point source assumption may result in poor performance. In this paper, we consider angle of arrival estimation when the signal sources are distributed. A parametric source model is proposed, and the estimation techniques based on the well-known maximum likelihood technique is considered under the model. In addition, Various statistical properties of the estimation errors were obtained.

• 제어로봇시스템학회논문지
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• 제19권4호
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• pp.290-298
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• 2013

Geomagnetic is refracted by building's wall and pillar. Therefore refracted geomagnetic is able to be used as feature point. In a specific space, a mobile device that is equipped with magnetic sensor array measures 3-axis magnetic field for each point. Magnetic field map is acquired by collecting the every sample point in the magnetic field. The measured magnetic field must be calibrated, because each magnetic sensor has a distortion. For this reason, sensor distortion model and sensor calibration method are proposed in this paper. Magnetic field that is measured by mobile device matches magnetic field map. Result of the matching is used for position estimation. This paper implements hardware system for position estimation method using magnetic field map.

• 한국환경과학회지
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• 제7권5호
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• pp.647-652
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• 1998

This study is to find out the emission estimation in Kimhae area. For this purpose, the Kimhae statistical yearbook and data of waste facilities issued by Kimhae city and the report on energy census issued by the ministry of trade, industry and energy are used. Each item for the emission estimation is $SO_2$, CO, HC, Nox, TSP from point, line, area sources. The results were as follows; The air pollutants with the highest mont of emission from the emission sources is CO followed by Nox, $SO_2$, TSP, HC in descending order of magnitude. The emission consists of 66.15% of line, 24.65% of area and 9.20% of point sources at Kimhae.

• 인터넷정보학회논문지
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• 제10권4호
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• pp.115-126
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• 2009

소프트웨어 규모 추정은 소프트웨어 Life-Cycle 초기에 분석되어 규모와 비용의 예측에 도움을 주어야 한다. 2004년 소프트웨어 사업대가 기준에 국제표준에 기반한 기능점수 방식이 도입된 후 사용자 입장에서 소프트웨어의 규모를 바라보고 비용을 산정하는 기반이 마련되었다. 그러나 현재의 기능 점수 측정 방식은 익숙하지 않은 일반 사용자가 접근하기 쉽지 않고, 모든 시스템 및 기능의 복잡도 가중치가 획일화되어 있어 내부 계산 로직이 복잡한 공학용 소프트웨어나 과학계산용, 시뮬레이션 소프트웨어에 대한 산정 방식에서 그 규모를 적절히 산정하지 못하는 문제점을 안고 있다. 본 논문에서는 기존의 기능점수 측정 절차를 간략화하고 프로젝트 초기에 규모의 추정을 쉽고 빠르게 수행할 수 있는 모델을 제시한다. 또한 특정 조직의 특성을 반영할 수 있는 수학적 가중치 산출 모형을 제시함으로써 고정된 복잡도 가중치에 대한 논란의 여지를 없애고 조직의 데이터가 쌓일수록 해당 조직의 특성을 반영해 나갈 수 있는 수학적 가중치 산출 모형을 제시한다. 제시한 모델은 평가 결과 기존의 FPA(Function Point Analysis) 방식보다 빠르게 규모를 측정할 수 있고 LOC(Line of Code)와의 상관관계도 더 높은 장점이 있다.

• Journal of the Korean Data and Information Science Society
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• 제24권6호
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• pp.1309-1317
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• 2013

일반화 지수분포 (generalized exponential distribution)를 따르는 점진 제 1종 구간 중도절단 (progressive type-I interval censoring) 표본에서 모수 추정은 Chen과 Lio (2010)가 최대우도 추정법 (maximum likelihood estimation), 중간점 근사법 (mid-point approximation method), EM 알고리즘 (expectation maximization algorithm), 적률 추정법 (method of moments estimation; MME)으로 하였으며, 그 방법들 중 평균제곱오차 (mean square error; MSE)가 가장 작은 추정법은 중간점 근사법이다. 하지만 중간점 근사법을 바탕으로 최대우도 추정법을 이용하여 모수를 추정하려고 한다면 모수에 대한 해를 전개할 수 없기 때문에 수치 해석적인 방법을 이용하여 추정하여야 한다. 본 논문에서는 이러한 문제를 해결하기 위해서 근사 최대우도 추정법 (approximate maximum likelihood estimation)을 이용하여 두 종류의 모수를 추정하고, 모의실험을 통하여 수치해석학적인 방법을 이용한 중간점 근사법의 해 (estimate of mid-point approximation method; MP)와 제시한 두 가지 추정량을 평균제곱오차 측면에서 비교한다.

• 제어로봇시스템학회논문지
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• 제20권4호
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• pp.414-421
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• 2014

This paper presents a method of ballistic missile launch point estimation using phase division least squares. The proposed algorithm employs smoothing to enhance estimation accuracy and generates functions of time for total velocity, flight path angle and heading angle, allowing extrapolation to estimate the launch point. Performance of the proposed algorithm is tested in conjunction with the extended Kalman filter and the Kalman filter.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2007년도 학술발표회 논문집
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• pp.855-859
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• 2007

It is essential to obtain accurate and highly reliable streamflow data for water resources planning, evaluation and management as well as design of hydraulic structures. A new discharge estimation method, which is named 'non-dimensional velocity distribution and index-velocity method,' was proposed in this research. This method showed very close channel discharges which were calculated with the exiting velocity-area method. When velocity-area method is used to estimate channel discharge, it is required to observe point velocities at every desired point and vertical using a current meter like Price-AA. However 'non-dimensional velocity distribution and index-velocity method' is used, it become optional to observe point velocities at every desired point and vertical. But this method can not be applied for the cases of very complex and strongly asymmetric channel cross-sections because non-dimensional velocity distribution by entropy concept may be quite biased from that of natural rivers.