• 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.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2005년도 춘계학술대회 논문집
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• pp.413-418
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• 2005

This paper proposes a measurement method for the surface of micro-parts by using AFM(Atomic Force Microscope). To this end, two techniques are presented to extend the capacity of AFM. First, the measurement range is extended by using an image matching method based on correlation coefficients. To account for the inaccuracy of the coarse stage implemented in AFM's, the image matching technique is applied to two neighboring images intentionally overlapped with each other. Second, a method to measure the shape of relatively large specimen is presented by using the inherent trigger mechanism due to the atomic force. The proposed method is proved effective through a series of experiments.

• 한국공작기계학회논문집
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• 제14권6호
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• pp.22-30
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• 2005

This paper proposes a measurement method for the surface shape of micro-parts by using an atomic force microscope(AFM). To this end, two techniques are presented: First, the measurement range is expanded by using an image matching method based on correlation coefficients. To account for the inaccuracy of the coarse stage implemented in AFM, the image matching technique is applied to two neighboring images intentionally overlapped with each other. Second, a method to measure the shape of relatively large specimen is proposed that utilizes the inherent trigger mechanism due to the atomic force. The proposed methods are proved effective through a series of experiments.

• 한국정보통신학회논문지
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• 제18권9호
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• pp.2237-2242
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• 2014

전 세계적으로 통신발달, 수명연장 등의 이유로 1인 가구가 급증하고 있으며 그에 따라 고독사 등의 문제점이 발생하고 있다. 이러한 문제점을 해결하고 사생활 침해가 없이 혼자서도 건강한 삶을 유지할 수 있도록 본 논문은 IR-레이더 및 레이저 변위센서를 이용하여 원거리 비접촉 생체신호 측정이 가능한 시스템을 제안하였다. 제안된 시스템은 원거리에서 비접촉으로 생체신호를 측정하는 방법으로, 실내 위치추적을 위한 IR 레이더 시스템과 비접촉 생체신호 측정을 위한 변위센서, 그리고 센서를 목표지점으로 이동하는 구동부로 구성되며 기존의 1m에 불과하던 생체신호 측정거리를 8m이상으로 늘릴 수 있는 시스템이다. 제안된 시스템을 실험을 통하여 타당성을 검증한 결과 정상적으로 측정이 가능하였다.

• 한국정밀공학회지
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• 제18권5호
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• pp.34-41
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• 2001

More accurate and fast inspection method for mechanical parts and structure is required to guarantee the safety. Conventional methods using compliance method, eddy current method, ultrasonic wave, acoustic emission for non-destructive testing in mechanical parts and structure have been performed as the method of contact with objects to be inspected. With this reason these methods have been taken relatively much time, money, and manpower. In this study, in order to overcome these shortcomings, we used In-plane Electronic Speckle pattern Interferometry(In-plane ESPI) that was full-field measurement and noncontact method. We detected the cracks of the specimen at a real time and measured the length of the crack by using In-place ESPI system. Finally, we compared this results with conventional microscope method.

• 비파괴검사학회지
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• 제25권4호
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• pp.287-293
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• 2005

유도초음파는 박판이나 봉재와 같은 구조를 효율적으로 검사할 수 있는 초음파로 주목받고 있으며, 더불어 시험체를 비접촉으로 검사할 수 있는 기법이 개발되면서 다양한 분야에 응용하기 위해 연구되고 있다. 본 연구에서는 비접촉식 초음파기법과 유도초음파의 장점을 결합하여 기존의 검사기법에 비해 효율적인 검사기법을 제안하고자 하였으며, 실험적인 검증을 위해 알루미늄 박판에 모의 부식결함을 가공하여 두께감육을 검출하고 평가하였다. 제안된 비접촉식 초음파기법으로는 EMAT을 이용하여 유도초음파를 발생 및 수신하였다. 선택된 유도초음파 모드의 분산거동특성에서 모드 컷-오프는 두께 감육을 검출할 수 있는 정성적인 파라미터이며, 군속도 변화는 두께 감육의 깊이를 정량적으로 평가할 수 있는 파라미터로 나타났다.

• 한국압력기기공학회 논문집
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• 제15권1호
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• pp.46-52
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• 2019

This work proposes a noncontact ultrasonic transducer for detecting wall-thinning of containment liner plates of nuclear power plants by measuring their thickness without physical contact. Because the containment liner plate is designed to prevent atmospheric leakage of radioactive substances under severe nuclear accident, its wall-thinning inspection is important for safety of nuclear power plants. Wall-thinning investigation of containment liner plates have been carried out by measuring their thickness with contact-type ultrasonic thickness gauge by inspectors and needs a lot of time and cost. As an alternative, an electromagnetic acoustic transducer measuring precisely thickness of containment liner plates without any physical contact or couplant was suggested in this research. A transducer generating and measuring shear ultrasonic waves in thickness direction was designed and wave field produced by the transducer was analyzed to verify the design. The working performance of the suggested transducer was tested with carbon steel plate specimens with various thicknesses. The test result shows that the proposed transducer can measure thickness of the specimens precisely without any couplant and implies that swift scanning of wall-thinning of containment liner plates will be possible with the proposed transducer.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 춘계학술대회논문집
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• pp.181-184
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• 2007

This paper deals with the method of vibration measurement of a gun barrel structure using mechanical filter. When a bullet with high speed is moving within a gun barrel type structure with low bending vibration frequencies, it is difficult to measure the bending vibration signals of the structure. For example, noncontact type sensors such as displacement or velocity sensor are not appropriate for the measurement of vibrational signals because of the movement effect of the equipment frame through the moving structures or effect of the ground vibration. One of contact type sensors such as accelerometer is profitable for measurement of vibrational signals because of its wide measurement ranges. In the case of a gun barrel structure including high vibrational signals like shock waves, however, it is necessary to propose vibration measurement method filtering high frequencies. The purpose of the paper is to propose the proper vibrational measurement technique filtering high frequencies of a gun barrel type structure.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2001년도 춘계학술대회 논문집(한국공작기계학회)
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• pp.137-142
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• 2001

Since recent production system becomes that of the small quantity, large volume with high quality production, accurate and high speed inspection system is required. In such situation, noncontact 3D measurement system which utilized CCD cameras is useful technique in terms of system cost, speed of data acquisition, measuring accuracy and application. However, it has low accuracy compared with contact 3D measurement system because of the camera distortion, non uniformity of laser distribution and so on. For those reasons, in this paper precision enhancement method is studied considering radial camera distortion, and laser distribution. A distortion correction method is applied even to the standard lens. The laser slit beam trajectory is determined by 3 method: based of the Gaussian function signal approximation, the median method, the center of gravity method and the peak point of the Gaussian function method.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2009년도 정보 및 제어 심포지움 논문집
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• pp.357-359
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• 2009

In this paper, the 2.4GHz doppler radar system consisting of the doppler radar module and a baseband module were designed to detect heartbeat and respiration signal without direct skin contact. A bio-radar system emits continuous RF signal of 2.4GHz toward human chest, and then detects the reflected signal so as to investigate cardiopulmonary activities. The heartbeat and respiration signals acquired from quadrature signal of the doppler radar system are applied to the pre-processing circuit, amplification circuit, and the offset circuit of the baseband module. ECG(electrocardiogram) and reference respiration signals are measured simultaneously to evaluate the doppler radar system. As a result, the respiration signal of doppler radar signal is detected to 1m without complex digital signal processing. The sensitivity and calculated from I/Q respiration signal were $98.29{\pm}1.79%$, $97.11{\pm}2.75%$, respectively, and positive predictivity were $98.11{\pm}1.45%$, $92.21{\pm}10.92%$, respectively. The sensitivity and positive predictivity calculated from phase and magnitude of the doppler radar were $95.17{\pm}5.33%$, $94.99{\pm}5.43%$, respectively. In this paper, we confirmed that noncontact real-time heartbeat and respiration detection using the doppler radar system has the possibility and limitation.