• 대한수의학회지
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• 제50권1호
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• pp.11-17
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• 2010

Linear and non-linear regressions were used to derive the calibration function for the measurement of roxithromycin plasma concentration. Their results were compared with weighted least squares regression by usual weight factors. In this paper the performance of a non-linear calibration equation with the capacity to account empirically for the curvature, y = ax$^{b}$ + c (b $\neq$ 1) is compared with the commonly used linear equation, y = ax + b, as well as the quadratic equation, y = ax$^{2}$+ bx + c. In the calibration curve (range of 0.01 to 10 ${\mu}g/mL$) of roxithromycin, both heteroscedasticity and nonlinearity were present therefore linear least squares regression methods could result in large errors in the determination of roxithromycin concentration. By the non-linear and weighted least squares regression, the accuracy of the analytical method was improved at the lower end of the calibration curve. This study suggests that the non-linear calibration equation should be considered when a curve is required to be fitted to low dose calibration data which exhibit slight curvature.

• 소음진동
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• 제1권2호
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• pp.107-113
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• 1991

When non-contact type vibration probes are used for the precision measurement of shaft vibration, they can induce the measurement errors due to the shaft curvature since they have been calibrated for the flat plate. In this study the errors due to the shaft radius and the misalignment between the shaft and probe centerlines are analyzed, and an in-situ calibration tool, which can be conveniently used for calibration independent of the shaft curvature and material, is introduced.

• 제어로봇시스템학회논문지
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• 제9권6호
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• pp.448-455
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• 2003

A system design technique of automatic thickness measurement and defect inspection system, which measures the thickness of the ALC(Autoclaved Lightweight Concrete) block and inspects the defect on a realtime basis is proposed. The image processing system was established with a CCD camera, an image grabber, and a personal computer without using assembled measurement equipment. The image obtained by this system was analyzed by a devised algorithm, specially designed for the enhanced measurement accuracy. For the realization of the proposed algorithm, the preprocessing method that can be applied to overcome uneven lighting environment, an enhanced edge decision method using 8 edge-pairs with irregular and rough surface, the unit length decision method in uneven condition with rocking objects, and the curvature calibration method of camera using a constructed grid are developed. The experimental results, show that the required measurement accuracy specification is sufficiently satisfied using our proposed method.

• 한국산학기술학회논문지
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• 제8권6호
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• pp.1319-1324
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• 2007

입출력 헤드 구조의 형상을 정확하게 조절할 수 있는 기술은 하드디스크 드라이브의 성능에 결정적인 요소이다. 본 논문에서 연구한 슬라이더는 알루미나 티타늄 카아바이드로 구성되었으며 디스크를 통과할 때 공기 베어링 역할을 한다. 그러므로 슬라이더의 곡률을 조절하는 것은 매우 중요하다. 본 연구에서 곡률을 조절하기 위해 헤드 슬라이더에 잔류응력을 발생시켜 곡률을 생성하는 레이저 화선 시스템이 사용된다. 슬라이더 형상의 조절을 강화하기 위해 화선(scribe)의 형상에 따른 곡률을 예측할 수 있는 방법이 중요하다. 레이저 화선과 유사한 효과를 얻을 수 있는 응력을 발생하는 하중계를 유한요소 모델에 적용한다. 하중계에 의해 형성된 곡률은 측정값을 통해 보정된다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1988년도 학술세미나 강연집
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• pp.71-123
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• 1988

The aim of this paper is to examine the end bearing capacity of a pile in cohesionless soils. The ode of failure of soil due to pile installation is assumed from experimental observation of actual soil deformation. A new solution is proposed complying with the assumed mode of failure by employing the theory of cavity expansion. The effect of curvature of failure envelope is studied in relation to tile proposed solution. The influence of a curved failure envelope becomes larger with increasing degree of curvature and the level of confining stress. This effect in some cases or reduce the end bearing capacity by tore the 80 percent compared with that given by a straight failure envelope. For practical application of tile proposed solution, the method of determining the average volume change in the plastic zone is re-evaluated. The proposed solution is confirmed by comparing the theoretical values with experimental results obtained from model pile tests in a calibration chamber. The comparison shows that the proposed solution provides a reasonable prediction of end bearing capacity for both weak and strong grained soils.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2000년도 춘계학술대회논문집 - 한국공작기계학회
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• pp.138-143
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• 2000

In order to maintain the faith and accuracy with precision of machinery, it is recently required the precise comprehension about approach which is appeared in the contact area between two bodies, because approach affects the static stiffness and dynamic characteristic of contact area. This study applied H. Hertz's circle contact area theory as much lower measuring force. It is measured approach influenced by various factors which were concerned with contact errors like material, form of two bodies, using calibration tester. As a result, the following conclusion can be obtained. 1) The approach appears greatly in order of carbon steel(SM20C), aluminum(A601-T6) and high density polyethylene(5305E) 2) The approach appears in order of concave, disc, convex form, in the ration of contact area size by the difference of curvature.

• 대한기계학회논문집B
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• 제24권2호
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• pp.188-194
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• 2000

Thermochromic liquid crystal reflect a unique color at even temperature. Therefore, they have been successfully applied to non-intrusive heat transfer research. Hue capturing method is widely used in the quantitative measurement from the TLC image. However it is affected by several measurement conditions. The distances of camera and light source have little influence on the color, but the value of hue is seriously affected by the measurement angle. In this study, the hue capturing method is improved by considering the effect of measurement angle. This improved calibration method can diminish the misreading of temperature caused by curvature of test surface.

• 로봇학회논문지
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• 제12권1호
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• pp.26-32
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• 2017

Previous shape sensors including bend sensors and optic fiber based sensors are widely used in various applications including goniometer and surgical robots. But theses sensors have large nonlinearity, limited in the range of sensing curvature, and sometimes are expensive. This study suggests a new concept of bend sensor using cable-conduit which consists of the outer sheath and the inner wire. The outer sheath is made of helical coil whose length of the central line changes as the sheath bends. This length change of the central line can be measured with the length change of the inner cable. The modeling and the experimental results show that the output signal of the proposed sensor is linearly related with the bend angle of the sheath with root mean square error of 5.3% of $450^{\circ}$ sensing range. Also the polynomial calibration of the sensor can decrease the root mean square error to 2.1% of the full sensing range.

• 한국광학회지
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• 제30권6호
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• pp.237-242
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• 2019

가상현실 기기의 렌즈는 사용자의 편의성을 위한 적은 부피와 높은 현실감을 위한 넓은 시야각을 동시에 만족시켜야 하기 때문에 왜곡 수차가 필연적으로 발생하는데, 일반적인 렌즈보다 시야각이 넓고 왜곡 수차가 크기 때문에 측정이 어렵다. 본 논문에서는 가상현실 기기의 특성을 고려한 두 가지 왜곡 측정 방법을 제안하였다. 하나는 카메라 교정 방법 기반의 다중 이미지를 이용한 왜곡 측정법이며, 또 다른 하나는 카메라를 포함한 측정부를 직접 회전시켜 왜곡을 측정하는 다중 측정점을 이용한 왜곡 측정법이다. 제안된 방법들의 검증을 위해 시판된 가상현실 기기인 Google Cardboard 제품의 왜곡을 측정하고 설계 데이터를 통한 시뮬레이션 결과와 비교하였으며, 두 방법으로 측정된 왜곡 값은 시뮬레이션 결과와 비교했을 때 잘 부합하는 것으로 나타났다.

• 제어로봇시스템학회논문지
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• 제10권6호
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• pp.494-500
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• 2004

This paper presents a machine vision system, which inspects the measurement of the ALC block on a real-time basis in the production process. The automatic measurement system was established with a CCD camera, an image grabber, and a personal computer without using assembled measurement equipment. Images obtained by this system was processed by an algorithm, specially designed for an enhanced measurement accuracy. For the realization of the proposed algorithm, a preprocessing method that can be applied to overcome uneven lighting environment, boundary decision method, unit length decision method in uneven condition with rocking objects, and a projection of region using pixel summation are developed. From our experimental results, we could find that the required measurement accuracy specification is sufficiently satisfied by using the proposed method.