• 제어로봇시스템학회논문지
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• 제8권11호
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• pp.976-983
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• 2002

We presents a modified variable dimension filter with input estimation for maneuvering target tracking. The conventional variable dimension filter with input estimation(VDIE) consists of the input estimation(IE) technique and the variable dimension(VD) filter. In the VDIE, the IE technique is used for estimation of a maneuver onset time and its magnitude in the least square sense. The detection of the maneuver is declared according to the estimated magnitude of the maneuver. The VD filter structure is applied for the adaptation to the maneuver of the target after compensating the filter parameter with respect to the estimated maneuver when the detection of the maneuver is declared. The VDIE is known as one of the best maneuvering target tracking filter based on a single filter. However, it requires too much computational burden since the IE technique is performed at every sampling instance and thus it is computationally inefficient. We propose another variable dimension filter with input estimation named 'Modified VDIE' which combines VD filter with If technique. Modified VDIE has less computational load than the original one by separating maneuver detection and input estimation. Simulation results show that the proposed VDIE is more efficient and outperforms in terms of computational load.

• 한국지구과학회지
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• 제38권5호
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• pp.323-332
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• 2017

The Digital Single Lens Reflex (DSLR) camera combined with a small aperture telescope is an efficient equipment for an astronomy-related lab exercise. This paper compares the different photometry softwares to provide insights on using the GUI-based photometry tool to the conventional command-line based photometry tool. The magnitude of the same point source measured within the aperture is consistent regardless of the software used although the background estimation, partial pixel treatment, and error estimation are slightly different. In a crowded field image where the aperture photometry is less reliable, the aperture photometry with varying aperture size is useful to see the qualitative trend for the magnitude. Due to the variation in ISO settings and the color dependence on the RGB Bayer system, an initial uncertainty of ~0.15mag is expected to be embedded in the magnitude derived from the DSLR images.

• 대한기계학회논문집A
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• 제26권10호
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• pp.2130-2141
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• 2002

A unique technique to estimate the magnitude or contribution ratio of each stage backlash in a system with a two-stage gear reducer is proposed. The concept to estimate the magnitude or contribution ratio of each stage backlash is based on the change of frequency response characteristic, in particular, the change of anti-resonant frequency and resonant frequency, due to the change of each stage backlash magnitude, even though the total backlash magnitude of a system with a two-stage gear reducer is constant. The validity of the technique is verified in a seeker gimbal and satisfactory results are obtained. It is thought that the diagnosis and maintenance of the manufacturing machines and systems with two-stage gear reducers will become more efficient and economical by virtue of the proposed technique.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 추계학술대회논문집
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• pp.1048-1052
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• 2003

This study aims to derive frequency weighting curves for the estimation of driver's discomfort by steering wheel vibration in the vertical and rotational direction with respect to a steering column. Subjective tests for the determination of equal sensation curves, inverse of frequency weighting curves, for the two kinds of vibrations were performed using the sinusoidal signals with reference amplitudes from 0.2m/s$^2$ to 0.4 m/s$^2$ in the frequency range from 5㎐ to 100㎐. Twelve subjects joined at the tests, and median values of the twelve judgments were used to determine the frequency weighting curves. Second experiment was followed to determine relative magnitude between the two frequency weighting curves by direct comparison of discomfort due to the two kinds of vibrations at 50㎐, which showed discomfort by the rotational vibration was 1.5 times of that by the vertical vibration.

• 한국통신학회논문지
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• 제22권1호
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• pp.185-192
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• 1997

We propose a method of paramete estimation using order-of-magnitude analysis for optimal boundary smoothing in Mean Field Annealing(MFA) technique in this paper. We previously proposed two boundary smoothing methods for consistent object representation in the previous paper, one is using a constratined regulaization(CR) method and the other is using a MFA method. The CR method causes unnecessary smoothing effects at corners. On the other hand, the MFA method method smooths our the noise without losing sharpness of corners. The MFA algorithm is influenced by several parameters such as standard deviation of the noise, the relativemagnitude of prior ter, initial temperature and final temperature. We propose a general parameter esimation method for optimal boundary smoothing using order-of-magnitude analysis to be used for consistent object representation in this paper. In addition, we prove the effectiveness of our parameter estimation and also show the temperature parameter sensitivities of the algorithm.

• 대한전기학회논문지:전력기술부문A
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• 제54권6호
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• pp.315-322
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• 2005

In this article, 1 would like to explore the estimation method of time-varying voltage sags in large industrial systems considering the short circuit contributions of rotating machines. For the power distribution system of KEPCO(Korea Electric Power Corporation), the magnitude of initial symmetrical short circuit current is generally not changed. However, in industrial systems which contain a number of rotating machines, the magnitude of voltage sag is generally changed from the initial to the clearing time of a fault due to the decreasing contribution of rotating machines for a fault current. The time-varying characteristics of voltage sags can be calculated using a short circuit analysis that is considered the time-varying fault currents. For this, the prediction formulations of time-varying voltage sags are proposed using a foreign standard. The proposed method contains the consideration of generator and motor effects. For the test of proposed formulations, a simple system of industrial consumer is used for the comparison conventional and proposed estimation method of voltage sag characteristics.

• 한국철도학회논문집
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• 제3권2호
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• pp.51-61
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• 2000

In this study, field measurements of vibration on the structures supporting railroad track were performed. The vibration data obtained were analyzed to find out any correlation between its magnitude and several factors such as type of bridges, distance from the track, type of train, frequency characteristics, etc. As a result, the magnitude of vibration turned out to be the highest in the steel bridge, the concrete bridge and steel-concrete combined bridge were the next in descending order. It was also found that the dynamic characteristics of ground were the most important factors among several affecting vibration near by the railroad track. And the empirical ground vibration estimation equation for estimating ground vibration was developed. The proposed equation with respect to distances from the railroad could be easily used for the estimation of ground vibration at the residential areas nearby the track.

• 한국인터넷방송통신학회논문지
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• 제14권2호
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• pp.65-71
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• 2014

본 논문에서는 모바일 디바이스에 기본적으로 제공되는 모노 카메라와 모노 마이크의 멀티 모달 입력을 통하여 사용자와 모바일 디바이스간의 거리를 추정하는 방법을 제안한다. 영상을 이용한 거리 추정은 모노 카메라로 입력되는 영상에서 피부색 영역을 추출하고, 노이즈를 제거한 후에 얼굴 영역 및 눈 영역을 검출하여 사용자의 거리를 추정한다. 음성을 이용한 거리 추정은 모노 마이크로 입력되는 음성으로부터 가장 큰 피크(Peak)를 선정하고, ROI(Region of Interest)를 지정한 후에 FFT(Fast Fourier Transform)을 수행하여 주파수 축에서의 크기(Magnitude)를 계산한다. 계산된 크기 값과 거리별 크기 값의 모델을 비교하여 거리 별 우도(Likelihood)를 계산하고, 정렬한 후 가중치를 주어 더함으로써 사용자의 거리를 추정한다. 실험결과 영상 및 음성을 멀티 모달 입력으로 이용하여 거리를 추정한 결과 단일 모달로 거리를 추정한 결과 보다 향상된 결과를 얻을 수 있었다.

• 디지털산업정보학회논문지
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• 제7권2호
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• pp.115-125
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• 2011

An accurate estimation of software development size is an important factor in calculating reasonable cost of project development and determining its success. In this study, we propose estimation models, using function point based on the functional correlation between software, with empirical data. Three models($FP_{est}(I)$, $FP_{est}(II)$, $FP_{est}(III)$) are developed with correlation and regression analysis. The validity of the models is evaluated by the significance test by comparing values of Mean Magnitude of Relative Error (MMRE) and predictions of each model at level n%. Model $FP_{est}(III)$ proved to be superior to other models such as IFPC(Indicative Function Point Count), EFPC(Estimated Function Point Count), EPFS(Early Prediction of Function Size), $FP_{est}(I)$, and $FP_{est}(II)$. As a result, the accuracy of the model appears to be very high to determine the usefulness of the model to finally overcome weakness of other estimation models. The model can be efficiently used to estimate project development size including software size or manpower allocation.

• 한국과학교육학회지
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• 제23권3호
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• pp.229-238
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• 2003

일상적인 경험을 바탕으로 중학생들이 도구를 사용하지 않고 물리량의 치수를 어림하는 능력을 조사하였다. 이를 위하여 연구자들은 기본량에 해당하는 길이와 질량, 유도량에 해당하는 속력, 부피, 밀도에 대한 차수 어림 능력을 묻는 선택형 문항을 개발하였고, 서울지역 중학교 1학년과 3학년 학생 448명이 조사에 참가하였다. 전체적으로 반 이상의 학생들이 물리량의 치수를 참값과 다르게 어림하고 있었는데, 차원이 복잡한 유도량이거나 크기가 작을수록 차수 어림 능력이 낮아졌다. 학년에 따른 차이는 크지 않았으나 성별에 따라서 차수 어림 능력에 차이가 있었고 상대적으로 남학생이 길이 어림을 잘 하였다. 결론적으로 반수 이상의 학생들이 물리량이 차수를 제대로 어림하지 못한다는 점은 물리량과 단위에 대한 정성적인 이해가 부족함을 나타내며, 기능적인 측면을 강조하는 측정 교육이 가지는 한계점을 보여주었다. 따라서 실제 측정을 통하여 구한 물리량의 정성적인 의미를 이해할 수 있도록 하기 위하여 어림 교육이 필요함을 시사하고 있다.