• 한국터널지하공간학회 논문집
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• 제14권3호
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• pp.197-213
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• 2012

디스크커터는 암석의 절삭을 위해 TBM에 사용되는 핵심 굴착도구이다. 본 연구에서는 디스크커터에 의한 암석의 절삭 시에 커터 링에 발생하는 변형특성을 파악하기 위하여, 경암에 대한 선형절삭실험 시에 커터 링에 부착한 일련의 변형률게이지와 적외선 열화상 카메라에 의한 계측을 실시하였다. 실험결과, 커터 링은 매우 뚜렷한 선형탄성 거동을 보였으며, 암석 절삭에 의한 커터 링의 온도 상승은 $14.4^{\circ}C$ 이내로 나타났다. 따라서 본 연구에서 수행한 선형절삭실험 조건에서는 절삭으로 인한 커터 링의 변형과 온도상승이 크지 않았음을 알 수 있었다.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제14권1_2호
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• pp.54-64
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• 1992

The balance of facial sop tissue is important factor for the treatment of maxillofacial deformity patients. There are many cephalometric analysis of facial bone but a few soft tissue analysis of face for the orthognathic surgery, especially in the oriental people. This study aimed at examining the mean value of the soft tissue measurement of 120 Korean adult women with the linear and angular measurement and comparing with Caucasian. The results ere as follows. 1. In the frontal linear measurement, Korean women have larger interocular distant and width of nose, but the width of mouth appeared less than Caucasian. 2. In the frontal angular measurement, Korean women have larger inclination of the eye than Caucasian. 3. In the lateral linear measurement, Korean women have more prominent upper and lower lip position than Caucasian and have longer upper facial height comparing with lower facial height than Caucasian. 4. In the lateral angular measurement, Korean women have more convex facial profile and less nasolabial and geniolabial angle. 5. In the lateral facial ratio, Korean women have larger proportion in the lower department below the stomion.

• 대한인간공학회지
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• 제24권4호
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• pp.7-13
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• 2005

We developed an accurate and reliable photogrammetric method available instead of the direct measurement method and the three-dimensional scanning method. Our research was restricted to a head on the body. Approaching three-dimensionally, we calibrated a distorted image of a photograph and got linear equations of camera beams. Then we assigned z values of landmarks in the head and obtained three-dimensional coordinates for each landmark putting those z values in linear equations of camera beams and finally could calculate measurement results from those three-dimensional coordinates. When we compared results obtained by a program, 'Venus Face Measurement(VFM)' that we had developed applying our method with results obtained by the direct measurement method, VFM showed very accurate and reliable results. In conclusion the photogrammetric method developed in this study was testified to an outstanding measurement method as a substitute for the direct measurement method and the three-dimensional scanning method.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1995년도 Proceedings of the Korea Automation Control Conference, 10th (KACC); Seoul, Korea; 23-25 Oct. 1995
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• pp.162-165
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• 1995

For an accurate on-line measurement of the ship's attitude the paper develops an intelligent sensing system which uses one servo-type accelerometer and two servo-type inclinometers appropriately located on the ship. By considering the dynamics of the servo-controlled rigid pendulums of the inclinometers, linear equations for the rolling and pitching of the ship are derived separately from each other. Moreover, one accelerometer is used for extracting the heaving signal. Through the introduction of linear dynamic models and the linear observation equations for the heaving, rolling and pitching, the on-line measurement of the three signals can be reduced to the state estimation of the linear dynamic systems. A bank of Kalman filters is adaptively used to achieve the on-line accurate state estimation and to overcome changes in parameters in the linear dynamic models.

• Journal of the Korean Statistical Society
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• 제24권2호
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• pp.303-312
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• 1995

We consider the following type of general semi-parametric non-linear regression model : $y_i = f_i(\theta) + \epsilon_i, i=1, \cdots, n$ where ${f_i(\cdot)}$ represents the set of non-linear functions of the unknown parameter vector $\theta' = (\theta_1, \cdots, \theta_p)$ and ${\epsilon_i}$ represents the set of measurement errors with unknown distribution. Under suitable finite-sample, small-dispersion asymptotic framework, we derive a general lower bound for the asymptotic mean squared error (AMSE) matrix of the Gauss-consistent estimator of $\theta$. We then prove the fundamental result that the general non-linear least squares estimator (NLSE) is an optimal estimator within the class of all regular Gauss-consistent estimators irrespective of the type of the distribution of the measurement errors.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 추계학술대회 논문집
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• pp.1073-1077
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• 1996

This paper presents a recoil and counter recoil(R&CR) motion measurement method using linear variable differential transformers(LVDT). The output of a LVDT is obtained from the differential voltage of the 2nd transformers. As a sensor core is attached at the motion body, the output is directly proportional to the core motion. Displacement, velocity and acceleration are measure from the core length. With a comparison between the measurement result and the known value which is obtained by the precision steel tape, the accuracy and the usefulness of the proposed scheme is validated.

• 한국항공우주학회지
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• 제30권1호
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• pp.105-113
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• 2002

본 연구에서는 터보프롭 엔진의 정상상태 성능해석 프로그램을 개발하고 비 장창 및 장착조건에서 성능이 해석되었다. 개발프로그램의 검증을 위해 GASTURB 8.0프로그램의 해석결과와 엔진 제작사의 주어진 성능자료를 비교하였다. 개발 프로그램은 GASTURB 8.0과의 비교 결과 5%내의 오차를 나타내어 프로그램의 신뢰성을 확인할 수 있었다. 성능진단을 위해 선형 및 비선형 GPA프로그램을 개발하였으며, 최적계측변수의 선정을 위한 연구를 수행하였다. 계측변수의 종류의 수가 진단의 정확성에 미치는 영향을 알아보기 위하여 선형 및 비선형 GPA프로그램은 다양한 변수를 이용하여 해석 되었다. 그 결고 적절하게 선택된 계측변수는 보다 적은 계측장비로도 신뢰성있고 경제적인 손상 탐지가 가능함을 확인하였다.

• Journal of Radiation Protection and Research
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• 제43권1호
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• pp.29-38
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• 2018

Background: Radon contributing about 42% of annual average dose, mainly comes from soil. In this paper, standard measurement procedures for soil radon exhalation rate are suggested and their measurement uncertainties are analyzed. Materials and Methods: We used accumulation method for estimating surface exhalation rate. The closed-loop measurement system was made up with a RAD7 detector and a surface chamber. Radon activity concentrations in the system were observed as a function of time, with data collection of 5 and 15-minute and the measurement time of 4 hours. Linear and exponential fittings were used to obtain radon exhalation rates from observed data. Standard deviations of measurement uncertainties for two approaches were estimated using usual propagation rules. Results and Discussion: The exhalation rates (E) from linear approach, with 30 minutes measurement time were $44.8-48.6mBq{\cdot}m^{-2} {\cdot}s^{-1}$ or $2.14-2.32atom{\cdot}cm^{-2}{\cdot}s^{-1}$ with relative measurement uncertainty of about 10%. The contributions of fitting parameter A, volume (V) and surface (S) to the estimated measurement uncertainty of E were 59.8%, 30.1% and 10.1%, in average respectively. In exponential fitting, at 3-hour measurement we had E ranged of $51.6-69.2mBq{\cdot}m^{-2} {\cdot}s^{-1}$ or $2.46-3.30atom{\cdot}cm^{-2}{\cdot}s^{-1}$ with about 15% relative uncertainty. Fitting with 4-hour measurement resulted E about $51.3-68.2mBq{\cdot}m^{-2} {\cdot}s^{-1}$ or $2.45-3.25atom{\cdot}cm^{-2}{\cdot}s^{-1}$ with 10% relative uncertainty. The uncertainty contributions in exponential approach were 75.1%, 13.4%, 8.7%, and 2.9% for total decay constant k, fitting parameter B, V, and S, respectively. Conclusion: In obtaining exhalation rates, the linear approach is easy to apply, but by saturation feature of radon concentrations, the slope tends to decrease away from the expected slope for extended measurement time. For linear approach, measurement time of 1-hour or less was suggested. For exponential approach, the obtained exhalation rates showed similar values for any measurement time, but measurement time of 3-hour or more was suggested for about 10% relative uncertainty.

• Journal of the Korean Data and Information Science Society
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• 제26권3호
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• pp.773-779
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• 2015

We study a statistical analysis about the fifth wave data of the Korea National Health and Nutrition Examination Survey based on linear regression models with measurement errors. The data is obtained from a national population-based complex survey. To demonstrate the availability of measurement error models, two results between the general linear regression model and measurement error model are compared based on the model selection criteria which are Akaike information criterion and Bayesian information criterion. For our study, we use the simulation extrapolation algorithm for measurement error model and the jackknife method for the estimation of standard errors.

• 한국초전도ㆍ저온공학회논문지
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• 제25권1호
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• pp.16-20
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• 2023

The International Electrotechnical Commission (IEC) 61788-26:2020 provides guidelines for measuring the critical current of Rare-earth barium copper oxide (REBCO) tapes using two methods: linear ramp and step-hold methods. The critical current measurement criterion, 1 or 0.1 μV/cm of electric field from IEC 61788-26 has been normally applied to REBCO coils or magnets. No-insulation (NI) winding technique has many advantages in aspects of electrical and thermal stability and mechanical integrity. However, the leak current from the NI REBCO coil can cause distortion in critical current measurement due to the characteristic resistance which causes the radial current flow paths. In this paper, we simulated the NI REBCO coil by applying both linear ramp and step-hold methods based on a simplified equivalent circuit model. Using the circuit analysis, we analyzed and evaluated both methods. By using the equivalent circuit model, we can evaluate the critical current of the NI REBCO coil, resulting in an estimation error within 0.1%. We also evaluate the accuracy of critical current measurement using both the linear ramp and step-hold methods. The accuracy of the linear ramp method is influenced by the inductive voltage, whereas the accuracy of the step-hold method depends on the duration of the hold-time. An adequate hold time, typically 5 to 10 times the time constant (τ), makes the step-hold method more accurate than the linear ramp method.