• Communications for Statistical Applications and Methods
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• 제9권1호
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• pp.213-220
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• 2002

Anthropometric survey is important as a basis for human engineering fields. According to our experiences, there are difficulties in obtaining the measurements of some body parts because respondents are reluctant to expose. In order to overcome these difficulties, we propose a method for estimating such hard-to-measure measurements by using easy-to-measure measurements those are closely related to them. Multiple Regression Model, Feedforward Neural Network(FNN) Model and Projection Pursuit Regression(PPR) Model will be used as analytical tools for this purpose. The method we propose will be illustrated with real data from the 1992 Korea national anthropometric survey.

• 대한치과교정학회지
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• 제35권3호
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• pp.163-173
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• 2005

본 연구는 안면비대칭 환자에서 경조직의 비대칭 정도와 연조직 비대칭 정도의 차이를 3차원적으로 밝히고자 시행되었다. 안면비대칭으로 보이는 성인 남녀 34명을 대상으로 두경부 전산단층사진을 촬영하고 3차원 입체영상으로 재구성한 후 기준평면에 대해 비대칭을 나타내는 5개의 계측항목을 경조직에 설정하고, 이에 대응하는 연조직 계측항목을 각각 설정한 후 3차원 계측을 시행하고 경조직과 연조직의 계측항목간 차이를 비교하였다. 이부편위측과 반대측간의 계측치 차이를 비교한 결과, 경조직과 연조직 모두에서 좌우측 계측치간에 통계적으로 유의한 차이가 관찰되었으며 경조직과 연조직의 비대칭 계측항목을 비교한 결과, 6개의 계측항목 모두에서 통계적으로 유의한 차이를 나타내었다. 이부편위를 나타내는 chin deviation, 하악지와 하악골체를 나타내는 frontal ramal inclination difference, frontal corpus inclination difference 항목은 경조직의 비대칭 정도에 비하여 연조직 비대칭 정도가 작게 나타난 반면, 입술경사를 나타내는 lip cheilion height difference, lip canting은 maxillary height difference, occlusal plane canting보다 크게 나타나 입술부위의 비대칭 정도는 하부 경조직의 비대칭 정도보다 큰 것으로 나타났다. 안면비대칭자에서 경조직과 연조직간 비대칭 정도 차이를 규명한 본 연구 결과는 안면비대칭 평가 시 경조직 외에 연조직 계측항목을 이용한 비대칭 분석도 필요함을 시사하였다.

• 한국해양공학회지
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• 제31권2호
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• pp.177-182
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• 2017

This paper describes an unscented Kalman filter approach to estimate the bias in magnetic field measurements. A microelectromechanical systems attitude heading reference system (MEMS AHRS) was used to measure the magnetic field, together with the acceleration and angular rate. A magnetic field is usually used for yaw detection, while the acceleration serves to detect the roll and pitch. Magnetic field measurements are vulnerable to distortion due to hard-iron effect and soft-iron effect. The bias in the measurement accounts for the hard-iron effect, and this paper focuses on an approach to estimate this bias. The proposed method is compared with other methods through experiments that implement the navigation of an underwater robot using an AHRS and Doppler velocity log. The results verify that the compensation of the bias by the proposed method improves the navigation performance more than or comparable to the compensation by other methods.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 춘계학술대회논문집
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• pp.1391-1395
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• 2006

In non-contact mode atomic force microscopy, the response of a resonating tip is used to measure the nanoscale topography and other properties of a sample surface. However, the tip-surface interactions can affect the tip response and destabilize the non-contact mode control. Especially it is difficult to obtain a good scanned image of high adhesion surfaces such as polymers using conventional hard NCHR tip and non-contact mode control. In this study, experimental investigation is made on the non-contact mode imaging and we report the microcantilever having low stiffness (OMCL) is useful to measure the properties of samples such as elasticity. In addition, we proved that it was adequate to use low stiffness microcantilever to obtain a good scanned image in AFM for the soft and high adhesion sample.

• Journal of the Optical Society of Korea
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• 제16권3호
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• pp.236-242
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• 2012

In general, such methods as interferometers or wavefront sensors are commonly used for testing of an optical system and optical components. In these cases, the surrounding environments are unlikely to affect the measurements. On the other hand, intraocular lenses of hydrophilic materials with special properties experience a certain difficulty in testing the optical properties. An intraocular lens is dried in the air, which causes deformation and changes the optical characteristics such as index of refraction and thickness. Thus, it is hard to measure the optical characteristics of an intraocular lens by using common methods. In this study, a special structure is used for measuring of the transmission wavefront aberration and effective focal length of an intraocular lens of hydrophilic materials by using a Shark-Hartmann sensor among the various measuring methods. As an application of this measuring method, this study shows a simple method to measure the index of refraction of unknown liquids with a plano-convex lens with a well known index of refraction. Also, this method is used to measure the optical properties of a plano-convex such as index of refraction and curvature by using a liquid with a well known index of refraction.

• Journal of Biosystems Engineering
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• 제37권5호
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• pp.319-326
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• 2012

Purpose: Cheese texture is an important sensory attribute mainly considered for consumers' acceptance. The feasibility of nondestructive measurements of cheese texture was explored using non-contact ultrasonic sensors. Methods: A novel non-contact air instability compensation ultrasonic technique was used for five varieties of hard cheeses to measure ultrasonic parameters, such as velocity and attenuation coefficient. Five texture properties, such as fracturability, hardness, springiness, cohesiveness, and chewiness were assessed by a texture profile analysis (TPA) and correlated with the ultrasonic parameters. Results: Texture properties of five varieties of hard cheese were estimated using ultrasonic parameters with regression analysis models. The most effective model predicted the fracturability, hardness, springiness, and chewiness, with the determination coefficients of 0.946 (RMSE = 21.82 N), 0.944 (RMSE = 63.46 N), 0.797 (RMSE = 0.06 ratio), and 0.833 (RMSE = 17.49 N), respectively. Conclusions: This study demonstrated that the non-contact air instability compensation ultrasonic sensing technique can be an effective tool for rapid and non-destructive determination of cheese texture.

• 대한환경공학회지
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• 제35권6호
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• pp.442-448
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• 2013

물속의 색도 측정방법에는 비색법과 분광학적방법이 있다. 비색법은 농도가 알려진 백금-코발트 표준용액과 시료의 색을 비교하여 색도를 측정하는 방법이며 분광학적 색도 측정방법은 단일 또는 다중파장을 선택하여 색도를 측정하는 방법이다. 그러나 비색법의 경우, 분석자의 시력에 의한 단순 비교를 통해 색도를 측정하는 방법으로 측정결과의 신뢰성과 재현성이 우수하지 못할 뿐만 아니라 5 TCU 이하의 색도 측정이 불가능하다. 분광학적 색도 측정방법 중 단일파장법은 주로 색도 성분이 천연유기물질(휴믹물질)인 지표수나 지하수에만 적용이 가능한 것으로 나타났으며 하수와 같이 인위적인 화학적 색도 성분이 함유될 경우 색도 측정이 불가능하였다. 다중파장법은 지표수, 하수 등 다양한 시료에 대해 우수한 색도 측정결과를 나타냈으나 1개의 시료에 대해 수십 번의 측정과 복잡한 계산으로 실제 현장 적용에 어려움이 있었다. 따라서 본 연구에서는 지표수, 정수, 하수 등 다양한 시료에 대해 신속하고 정확한 색도 측정방법을 비교하였다. 그 결과, 다중파장 프로그램이 내장되어 3~4초 이내에 지표수, 하수 등 다양한 시료에 대해 신속하고 정확하게 색도 측정이 가능한 색도계 색도 측정방법이 가장 적합한 것으로 나타났다.

• 한국해안해양공학회지
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• 제16권3호
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• pp.171-177
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• 2004

디지털 영상을 이용한 새로운 파고계를 연구ㆍ개발하였으며 실험실의 조파 수조를 사용하여 검증하였다. 본 연구는 비디오 동영상이 1/15초의 일정한 간격으로 영상을 촬영하는 규칙성과 아날로그 영상에서 디지털 영상으로의 변환, 그리고 큰 용량의 저장 매체를 활용하였다. 본 파고계는 수면의 움직임에 따라 동일하게 움직이는 부이를 촬영한 영상에서 그 움직임을 자동으로 추출하는 방법으로 파고 관측을 하였으며 참값과 비교 검증하였다. 차후 개선 연구를 통하여 해안에 근접한 천해역에서 파랑 관측을 하는데 활용할 수 있을 것으로 보인다.

• 한국군사과학기술학회지
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• 제14권1호
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• pp.55-61
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• 2011

This paper presents bubble wake measurement results generated by the planing hull. The bubble was generated by SNAME TMB model(No. 4876) with hard chine at the CWC(Circulating Water Channel). ABS(Acoustic Bubble Spectrometer) was used to measure bubble wake measurement. The manufactured model is one meter in length and uniform velocity to generate the bubble at CWC is 3m/s, relatively higher speed than conventional hull form. Measurements were performed successfully and measured results show well the general characteristics of bubble wake generated by planing hull. Furthermore, experimental equations are proposed for the practical use.

• 한국응급구조학회지
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• 제23권1호
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• pp.61-69
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• 2019

Purpose: The study aims to provide basic data to enhance the health of paramedics responsible for patient transport and treatment by analyzing the exposure level of paramedics to electromagnetic waves generated by electric devices used in ambulances. Methods: The study measured electromagnetic waves in ambulances in N region from July to December 2018. ME3030B produced by German Gigahertz Solutions was used to measure these waves and the maximum value was selected by moving it slowly in various directions. Each measurement part was selected and the mean value was calculated by repeatedly measuring at 10-minute intervals three times in total: $1^{st}$, $2^{nd}$, and $3^{rd}$ phase. Results: Among the electrical devices installed in the patient room of the ambulance measured at distances of 1 cm or 30 cm, results showed a high level of electric waves at the inverter ($26.25{\pm}39V/m$) and high level of electromagnetic waves ($564.00{\pm}31.75nT$) at the ozone sterilizer. According to measurements toward the front near the driver's seat, results indicated high levels of electric waves ($3.67{\pm}1.15V/m$) and electromagnetic waves ($450.00{\pm}19.52nT$) at the black box hard drive. Conclusion: Electromagnetic waves within the ambulance were stable and not beyond the range that might impact human health. However, in the case of the black box hard drive ($3.67{\pm}1.15V/m$, $450.00{\pm}19.52nT$) located under the passenger seat, it may have a direct effect on the human body and, thus it is necessary to move it to a storage area further away from the paramedics to minimized the impact.