• 대한한의진단학회지
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• 제12권2호
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• pp.8-17
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• 2008

Objectives: For the traditional pulse diagnosis in Oriental Medicine, not only the pulse shape in time domain, but the width, length and depth of arterial pulse also should be measured. However, conventional pulse diagnostic systems have failed to measure the spatial parameters of the arterial pulse e.g. effective length of arterial pulse in the wrist. In fact, there are many ways to measure that kind of spatial features in arterial pulsation, but among them, the method using image sensor provides relatively cheap and simple way, therefore I tested feasibility of measuring 2-dimensional pressure distribution by imaging devices. Methods: Using widely used PC cameras and dotted balloons, the subtle oscillation of skin over the radial artery was recorded continuously, and then the displacement of every dot was calculated. Consequently, the time course of that displacements shows arterial pulse wave. Results: By the proposed method I could get pressure distribution map with 30Hz sampling rate, 21steps quantization resolution, and approximately 1mm spatial resolution. With reduced quantization resolution, $3cm{\times}4cm$ view angle could be achieved. Conclusion: Although this method has some limitations, it would be useful method for detecting 2-dimensional features of arterial pulse, and accordingly, this method provides a novel way to detect 'narrow pulse', 'wide pulse', 'long pulse', 'short pulse', and their derivatives.

• 한국생산제조학회지
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• 제24권3호
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• pp.314-319
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• 2015

Invar is a compound metal of Fe-Ni system contained 36.5% Ni. The characteristic of invar is that the coefficient of thermal expansion is $1.0{\times}10^{-6}cm/^{\circ}C$. It is approximately 10 times smaller than series of steel. Because of this low thermal expansion characteristic of Invar, it is used to shadow mask of display device such as UHDTV or OLED TV. In this study, pulse current from pulse generator instead of DC current is used to overcome the disadvantages of the conventional electrochemical machining. Pulsed current with different duty factor in PECM affect the precise geometry. Pulse electrochemical machining is conducted to machine the micro hole to the invar sheet with different duty factor. The machined shape and overcut of invar sheet with different duty factor is observed by optical microscope and scanning electron microscope (SEM).

• 한국통신학회논문지
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• 제19권1호
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• pp.1-9
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• 1994

In general, when IIR digital filter are designed from analog filters, the bilinera transformation and the impluse invariant tramsformation are commonly used. It is known, however, that high frequency response of digital filters designed by these transformations can not be well approximated to the sampled analog signals. In this paper, the symbol pulse invariant transformation is analyzed theoretically so that the symbol pulse invariant transformation which was originally application to a rectangular pulse is newly applied to double rate pulse signals and generic shape pulse signals. Also, the relation of spectra between a transfer function of digital filter and one of analog filter is considered. Further, we apply to design the digital high pass filters using the symbol pulse invariant transformation method.

• 대한한방내과학회지
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• 제34권3호
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• pp.231-239
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• 2013

Objectives : This study was performed to evaluate inter-rater and intra-rater reliability of interpretation and reproducibility of a pulse analyser (MAXMAC27-Plus). Methods : 38 of 40 volunteers completed the pulse analysis consecutively. Three Korean medical doctors who had at least 2 years of clinical experience interpreted the pulse waves for 3 aspects of size, depth and shape, then inter-rater reliability and crude agreement was obtained. Reinterpretation was done 2 weeks later and intra-rater reliability and crude agreement was obtained. Intra-rater reliability and crude agreement between 1st and 2nd measurement was calculated. Cohen's weighted kappa for size, Cohen's kappa for depth and shape were used as statistical analysis. Results : Inter-rater reliability of size, depth and shape among 3 raters was 0.598, 0.604, and 0.312, respectively, showing moderate to substantial agreement. Average intra-rater reliability between 1st and 2nd interpretation of size, depth and shape was 0.806, 0.705, and 0.638, respectively, showing substantial to almost perfect agreement. However, intra-rater reliability between consecutive measurements of size, depth and shape was 0.221, 0.121, and 0.194, respectively, which showed only poor to fair agreement. Conclusions : Intra-rater and inter-rater reliability of one pulse wave showed relatively high concordance. Training by a clinical expert may effect better concordance among raters. Test-retest reliability showed poor agreement. Improvement of measurement technique and device performance will be needed.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.1914-1915
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• 2007

The period and strength of the pulse on the radial artery are important physiological factors, and they have been used to diagnosis in both Western and Eastern countries for a long time and has been developed as a unique method of diagnosis at each countries. Recently, there are a lot of systems which can give diagnosis information by recording the pulse wave and analyzing the characteristics of the pulse shape. This study describes the Pulse-Wave Measurement System which is able to measure the pulse wave signal using piezoresistive sensor and the pulse wave signal measured by the developed system is transmitted to a computer on the basis of the USB Driver. It has finally shown the the pulse wave signal measured by the sender is appeared to the host PC in real time. The Pulse-Wave Measurement System used the piezoresistive sensor to measure the pulse wave signal and the differential amplifier(AD620) to amplify the pulse wave signal which is small signal. And it used the ADC to convert analog to digital for the measured analog signal and the interface with a computer. It transmitted the measured pulse signal through USB transmission module to the host computer and Labview tool shows it. This Pulse-Wave measurement system will afford comvenience of detecting pulse wave to user related to oriental medicine.

• 한국산학기술학회논문지
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• 제14권12호
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• pp.6114-6118
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• 2013

본 연구에서는 초음파 탐상시험의 펄스 반사법으로 각각 용접결함에 따른 초음파 펄스파형모형을 연구하였다. 균열은 예리하고 선명한 신호들을 발생한다. 탐촉자를 결함주위로 이동하면 에코높이는 변한다. 긴 균열에서는 탐촉자가 결함 주위를 원형으로 목돌림주사법을 사용하여 탐상하면 에코높이는 급격히 감소한다. 그 에코 봉우리는 바늘과 같이 얇고 날카롭다. 기공은 단일 결함으로부터 발생하는 에코는 예리하고 선명하다 하지만 집단의 기공들은 다수의 반사들이 중첩되고 트레이스가 들쭉날쭉한 에코가 발생한다. 슬래그 개재물은 크랙과 슬래그 결함위치에서 각각 목돌림 주사법을 사용하여 탐상하면 그 에코형상은 어느 정도 차이를 볼 수 있었다. crack은 그 에코높이가 급격히 변하는 반면에 슬래그 개재물은 증가${\rightarrow}$감소${\rightarrow}$증가${\rightarrow}$감소된다. 또한 다수 밀집된 기공의 위치에서 결함은 대표적 에코형상과 같은 잡다한 에코형상은 슬래그에서는 볼 수 없었다. 용입불량은 결함의 에코형상은 크랙과 같이 날카롭고 예리하게 나타났고, crack과 비슷한 에코형상은 갖고 있었다.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2009년도 학술대회 초록집
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• pp.198-202
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• 2009

스플릿 홉킨슨 압력 봉(SHPB)실험은 암석 및 콘크리트와 같은 취성재료의 동적 물성과 변형특성을 파악하고 압축 응력-변형율 데이터를 획득하기 위하여 사용된다. SHPB 실험법은 원리상 대상시료가 파괴이전에 동적응력평형 상태와 일정 변형율 속도 조건하여 놓여져 있어야 한다. 이러한 조건을 만족시키기 위하여 충격봉과 입사봉의 충격에 의하여 발생되는 충격 입사파형을 제어할 필요가 있다. 최근에는 원형 디스크를 충격봉과 입사봉 사이에 두어 입사 충격파형을 제어하는 펄스쉐이핑 기법이 적용되고 있다. 본 연구에서는 입사 충격파형을 정밀하게 제어할 목적으로 다양한 형태와 크기의 금속디스크를 대상으로 SHPB 실험을 수행하여 동적 변형 특성을 파악하였다. 펄스쉐이퍼의 두께와 직경이 작아짐에 따라 응력값과 파장은 증가하였다.

• 한국레이저가공학회지
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• 제4권1호
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• pp.29-38
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• 2001

This work was carried out to investigate the welding behavior of thin A3003 Al alloy sheets by Nd : YAG laser beam. Considering bead shape and mechanical properties, the laser pulse shapes selected were two kinds of 2-division and 3-division by varying power level and pulse duration. In order to obtain optimum conditions, the factorial design method and central composite design method were applied. Tensile test, optical microscopy, micro hardness test and TEM analysis were performed. Due to the annealing caused by thermal effect during laser welding, precipitates were coarsended. The HAZ was softened and failed during tensile test. The hardness of HAZ was lower than that of base metal, since the heat input relieved the work hardening effect and caused grain growth.

• Journal of Advanced Marine Engineering and Technology
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• 제32권1호
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• pp.137-146
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• 2008

Nd:YAG pulse laser welding of stainless steel plate was simulated to find welding condition by using commercial finite element code MARC. Due to geometric symmetry, a half model of AISI 304 stainless steel plate was considered and user subroutines were applied to boundary condition for the heat transfer. Material properties such as conductivity, specific heat, mass density and latent heat were given as a function of temperature. As results, Three dimensional heat source model for pulse laser beam conditions of butt welding has been designed by the comparison between the finite element analysis results and experimental data on AISI 304 stainless steel plate. Nd:YAG laser welding for AISI 304 stainless steel was successfully simulated and it should be useful to determine optimal welding condition.

• 대한기계학회논문집A
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• 제22권1호
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• pp.52-63
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• 1998

The impact programmer for impact test was designed and the impact analysis was conducted. The effects of the material and geometric parameters on the impact force and pulse shape were investigated. The impact characteristics were examined by experimental and finite element method. The impact test was conducted with free drop impact tester. The ABAQUS/Explicit 5.5 version was used for finite element analysis. The geometric parameters of the conical and dome type impact programmer were analyzed. The polyurethane impact programmers were fabricated and tested. The effects of the hardness and thickness of the impact programmer were studied. The peak acceleration and time duration of impact programmer have close correlation with the hardness, impact energy and thickness of the impactor. The experiment was good agreement with analytical predictions. The impact pulse shape generated with polyurethane impact programmer was half sine shape. The maximum impact force was proportional to impact energy. The impact acceleration was decreased with thickness of impact programmer. The maximum impact time duration level was about 2 msec.