• 한국차세대컴퓨팅학회논문지
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• 제15권3호
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• pp.25-30
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• 2019

지자기 벡터는 센서가 바라보고 있는 방향에 따라 그 값이 달라지는 특성이 있다. 본 논문에서는 그런 문제를 최소화하여 지자기 기반 실내 위치 추정에 사용될 수 있도록 지자기 벡터 보정법을 제안한다. 지자기 기반 실내 위치 추정에서 사용되는 핑거프린팅 기법은 자기장 지도와 현재 위치에서의 자기장 값을 매칭하여 위치를 추정해낸다. 이때, 자기장 센서는 사용자의 이동 방향에 따라 읽어 들이는 자기장 벡터 값이 달라지기 때문에 위치 추정 정확도가 낮아진다. 이를 해결하기 위해 많은 연구들은 자기장 벡터 크기를 사용하지만, 이는 지문의 고유성을 감소시킨다. 따라서 본 논문에서는 지문의 고유성을 유지할 수 있는 자기장 벡터를 그대로 사용하되, 벡터 크기처럼 사용자의 이동방향에 영향을 받지 않도록 벡터 값을 보정하는 방법을 제안한다. 임의의 방향으로 걸어본 결과, 본 연구에서 제안된 보정법을 사용하면 자기장 지도와의 매칭 정확도가 높아지는 것을 확인하였다.

• 한국전자파학회논문지
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• 제21권4호
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• pp.433-442
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• 2010

본 논문에서는 멀티베이스라인 인터페로미터 방향 탐지 시스템에서 진폭 및 위상 부정합 오차를 보정할 수 있는 공분산행렬 기반 자체 교정 알고리즘을 제안한다. 제안된 기법은 비용함수를 정의한 후 제한 조건을 갖는 비선형 최소화 방법으로서, 공간 섹터를 이용하여 부정합 오차를 획기적으로 교정하는 알고리즘이다. 다만 공간 섹터를 선정하기 위하여 초기 추정각을 요구하는 단점이 있으나, 이는 일반적인 비선형 최소화 문제의 공통적인 단점이다. 적절한 공간 섹터 간격을 선정하여 시뮬레이션한 결과, 제안된 방법이 기존 인터페로미터 방식보다 표본바이어스, 표본표준편차, 평균제곱오차면에서 획기적으로 우수한 통계적 성능을 보여주었다. 더구나 섹터 간격이 도래각과 $5^{\circ}$ 이내일 경우에, 30 dB의 진폭 부정합 및 $50^{\circ}$ 이상 큰 값의 위상 부정합이 발생하는 경우에도 획기적인 보정 능력을 보여주었으며, 신호대 잡음비에도 덜 민감한 특징을 나타내었다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집B
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• pp.48-52
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• 2001

In this paper presents an accurate AFM used that is free from the Z-directional distortion of a servo actuator is described. Two mathematical correction methods by the in-situ self-calibrationare employed in this AFM. One is the method by the integration, and the other is the method by inverse function of the calibration curve. The in situ self-calibration method by the integration, the derivative of the calibration curve function of the PZT actuator is calculated from the profile measurement data sets which are obtained by repeating measurements after a small Z-directional shift. Input displacement at each sampling point is approximately estimated first by using a straight calibration line. The derivative is integrated with reference to the approximate input to obtain the approximate calibration curve. Then the approximation of the input value of each sampling point is improved using the obtained calibration curve. Next the integral of the derivative is improved using the newly estimated input values. As a result of repeating these improving process, the calibration curve converges to the correct one, and the distortion of the AFM image can be corrected. In the in situ self-calibration through evaluating the inverse function of the calibration curve, the profile measurement data sets were used during the data processing technique. Principles and experimental results of the two methods are presented.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 학술대회 논문집 정보 및 제어부문
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• pp.583-585
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• 2004

In this paper we will deal with a calibration method for low cost motion capture system using psd(position sensitive detection) optical sensor. To measure the incident direction of the light from LED emitted marker, the PSD is used the output current ratio on the electrode of PSD is proportional with the incident position of the light focused by lens. In order to defect the direction of the light, the current output is converted into digital voltage value by opamp circuits peak detector and AD converter with the digital value the incident position is measured. Unfortunately, due to the non-linearly problem of the circuit poor position accuracy is shown. To overcome such problems, we compensated the non-linearly by using least-square fitting method. After compensated the non-linearly in the circuit, the system showed more enhanced position accuracy.

• 풍력에너지저널
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• 제4권2호
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• pp.34-39
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• 2013

The wind resource assessment for measured wind data over 1 year by using the meteorological mast should be a prerequisite for business feasibility of the wind farm development. Even though the direction of boom mounting the wind vane and anemometer is carefully engineered to escape the interference of wakes generated from the met-mast structures, the shadow effect is not completely avoided due to seasonal winds in the Korean Peninsula. The shadow effect should be properly calibrated because it is able to distort the wind resources. In this study a calibration method is introduced for the measured wind data at Julpo in Jeonbuk Province. Each sectoral terrain conditions along the selected wind direction nearby the met-mast is investigated, and the distorted wind data due to shadow effects can be calibrated effectively. The correction factor is adopted for quantitative calibration by carrying out the WindSim analysis.

• 산업기술연구
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• 제22권A호
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• pp.49-57
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• 2002

The accurate wind speed information at the hub height of a wind turbine is very essential to the exact estimation of the wind turbine power performance testing. Several methods on the site calibration, which is a technique to estimate the wind speed at the wind turbine's hub height based on the measured wind data using a reference meteorological mast, are introduced. A site calibration result and the wind resource assessment for the Taekwanryung test site are presented using a one-month wind data from a reference meteorological mast and a temporal mast installed at the site of wind turbine. From this analysis, it turns out that the current location of the reference meteorological mast is wrongly determined, and the self-developed codes for the site calibration are working properly. Besides, an analysis on the uncertainty allocation for the wind speed correction using site calibration is performed.

• 한국연소학회지
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• 제5권1호
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• pp.91-98
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• 2000

We investigated a uniform temperature zone, produced by double flame structure of a co flow CH4/air partially premixed flame, to be used as a temperature calibration source for laser diagnostics. A broadband N2 CARS(coherent anti-Stokes Raman spectroscopy) system with a modeless laser was used for temperature measurement. When the stoichiometric ratio was 1.5, we found the uniform temperature zone in radial direction of the flame of which the averaged temperature was 2110 K with standard deviation 24 K. In the stoichiometric ratio range between 2.0 and 2.5, we found very stable temperature-varying zones in vertical direction at the center of the flame. The size of the zone was approximately 15 mm and it covered a temperature range from 300 K to 1900 K. We also suggest that this zone can be used as a calibration source for 2-D PLIF(planar laser induced flurescence) temperature measurement.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.1568-1572
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• 2004

This paper proposes a new online calibration algorithm for the array antenna system. As you know, the several previous calibration methods for the mutual coupling did not estimate but measure mutual coupling effect at the real or test-bed system directly. Therefore we suggest some idea to compensate the calibration errors due to mutual coupling effect and mismatch in cables and electronic modules without the off-line calibration. In this work, we can calibrate the array antenna system under the operation of the system using Independent Component Analysis(ICA). This is what is called an online calibration. As you know, the ICA method has permutation and scaling problems. However, we solve problems of the ICA method and apply it to the calibration of an array antenna. The method simultaneously estimates the DOA(Direction of Arrival) of the signals, and calibrates the array for that specific angle. The proposed algorithm is evaluated by computer simulation and its behavior is illustrated by a numerical example.

• 한국항공운항학회지
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• 제11권1호
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• pp.41-55
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• 2003

A calibration jet system using separate blower is developed to calibrate a flow sensor effectively. Designed open circuit type mini calibration jet system, which has the dimension of $0.5m(W){\times}1.17m(H)$ is small compared with conventional calibration jet systems. The exit of nozzle has exchangeable contractions with a cross section area of $38.5cm^2$ , and a cross section area of $113.1cm^2$, respectively. The ranges of wind speed at exit of exchangeable nozzles are $7.5{\sim}42\;m/s$ and $1.8{\sim}16.5\;m/s$, respectively. The input power for the high pressure blower is 1.18kW. The turning vanes for corner was rolled flat plate parallel to the flow direction. The flow conditioning screen was located immediately downstream of the wide-angle diffuser. The honeycomb and two flow conditioning screens were located in the stagnation chamber. From the economical point of view and the simplicity of the calibration jet system set up and handling, it can be said that the developed calibration jet system is an effective calibration jet system. This system can also be used to calibrate the flow sensor with high resolution.

• Journal of Mechanical Science and Technology
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• 제18권12호
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• pp.2250-2257
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• 2004

The accurate wind speed information at the hub height of a wind turbine is very essential to the exact estimation of the wind turbine power performance testing. Several methods on the site calibration, which is a technique to estimate the wind speed at the wind turbine's hub height based on the measured wind data using a reference meteorological mast, are introduced. A site calibration result and the wind resource assessment for the TaeKwanRyung test site are presented using three-month wind data from a reference meteorological mast and the other mast temporarily installed at the site of wind turbine. Besides, an analysis on the uncertainty allocation for the wind speed correction using site calibration is performed.