• 대한기계학회논문집
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• 제16권9호
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• pp.1643-1653
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• 1992

본 연구에서는 해석적 모우드해석 결과인 모우드 형상벡터를 이용하여 효과적 인 가진점과 응답측정점을 선정하는 기존의 두 방법에 대해 간략히 기술하고 비교검토 하고자 하였다. 첫번째 방법은 주파수응답함수에서 관심있는 모우드의 공진피크치와 관련있는 모우드상수를 이용하는 것이고, 두번째 방법은 계의 관심있는 모우드에 대한 동적 특성을 가장 잘 나타낼 수 있도록 특이치분해(singular value decomposition) 기 법을 적용함으로써 계의 대표자유도(master degree of freedom) 지점들을 선저하는 것 이다.우선 단순한 계인 외팔보아 알루미늄평판에 대해 두 방법을 적용함으로써 비 교검토하였고, 이 결과로부터 두번째 방법의 우수성을 확인할 수 있었다. 이에 따라 보다 복잡한 형상을 갖는 승용차의 부분구조물인 조향휠고정대 (deck cross member : DCM)에 대해서 두번째 방법을 이용하여 모우드 시험을 수행하고 그 결과에 대하여 논 하였다.

• 센서학회지
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• 제22권6호
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• pp.410-414
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• 2013

As one of the effective methods for researching the objective tinnitus detection, the GPIAS (Gap Pre-pulse Inhibition of Acoustic Startle) measurement has been used to verify the existence of animal tinnitus objectively. The level and pattern of the background sound presented prior to a startle pulse are closely related with the GPIAS results. But the effect of the starting point of the background sound on animal startle responses has not been reported yet. In this paper, we present the implementation of a GPIAS measurement system based on an unconstrained enclosure to avoid animals' excessive constraint stress and deal with the animals' growth. After the performance of our implemented system has been tested through the animal experiment using 4 SD-rats, the effect of starting point of stimulus background sound on the startle response has been studied by the use of our implemented system. Through the results, it is verified that our system can measure the inhibition of animal startle responses due the gap pre-pulse for GPIAS calculation and the background sound starting point does not significantly effect on the startle response and the GPIAS values if the background sound continues for more than 300msec before a gap pre-pulse is presented.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 추계학술대회논문집
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• pp.831-835
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• 2003

The objective of this paper is to suggest an experimental technique to measure the out-of-plane vibration intensity of a coupled plate. In order to measure the out-of-plane vibration intensity of the plate, the frequency response technique has been implemented. In this technique, the 2-D intensity vector at a measurement point has been estimate from the frequency response functions measured at 4 points in the neighborhood of the measurement point. The experimental result has been compared with a theoretical result. It showed that the experimental technique can be effectively used to measure the out-of-plane vibration intensity of plates.

• 한국기계가공학회지
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• 제18권5호
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• pp.1-8
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• 2019

Breath analysis using a portable device is better than the classical breath analysis system in terms of installation and operation. There is an increasing need to develop cost-effective equipment for testing gas sensors from the viewpoint of functionalities that can be applied applicable to portable devices. In the present study, an economical gas chamber for in-situ gas measurement is implemented with a single gas chamber without using expensive gas storage and control equipment; the gas response characteristics are analyzed using the above-described chamber. The main features of the implemented gas chamber are simple injection procedure, improved gas diffusion, easy measurement and cleaning, support for low-power mode measurement function for portable devices, and open source platform. Moreover, an analysis of gas response characteristics based on changes in sensor voltage show that the sensitivity and 90% response time are affected by the sensor voltage. Furthermore, the sensitivity graph has an inflection point in a specific range. The gas sensor applied in this study showed fast response speed and high sensitivity for sensor voltages of 3.0-3.5 V, regardless of the concentration of acetone gas, the target gas used in this study.

• Smart Structures and Systems
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• 제25권6호
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• pp.679-691
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• 2020

To identify the bridge information from the response of test vehicles passing on it (also known as the indirect approach) has aroused the interest of many researchers thanks to its economy, easy implementation and less disruption to traffic. The surface roughness of bridge remains an obstacle for such method as it contaminates the vehicle response severely and thereby renders many vehicle-response-based bridge identification methods ineffective. This study aims to eliminate such effect with the responses of two different test vehicles. The proposed method can estimate the surface profile of a bridge based on the acceleration data of the vehicles running on the bridge successively, and obtain the normalized contact point response, which proves to be relatively immune to surface roughness. The frequencies and mode shapes of bridge can be further extracted from the normalized contact point acceleration with spectral analysis and Hilbert transform. The effectiveness of the proposed method is verified numerically with a three-span continuous bridge. The influence of measurement noise is also examined.

• 한국한의학연구원논문집
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• 제14권2호
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• pp.113-119
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• 2008

In pulse diagnosis, floating pulse and sinking pulse are frequently used for diagnosis about where disease is located and how much severe they are. However, in what mechanism floating pulse and sinking pulse arise is not known well. There are two point of views on substantial of floating pulse and sinking pulse. The first one is the floating and sinking degrees is the expression on the depth of pulsation. And, the second one is floating and sinking pulse is based on the response of pulsation to the indent pressure on radial artery. In this paper, we discussed these two opinions in the view point of tonometric measurement. The process for diagnosis on floating pulse and sinking pulse is similar to the tonometric measurement for non invasive blood pressure or intraocular pressure. We modelled the degrees of depth of pulsation with different indent pressures for initial pulsation feeling and different slopes of indent pressure lines. From this modelling, we can confirm the effect of pulsation depth on P-H curve, that is, in the model where lower pulsation is assumed, the shift of optimal indent pressure to the right was observed. The response of pulse pressure to the indent pressure was tried to be modelled with the degrees of mean blood pressure. Consequently, we tried to model the phenomenon of floating and sinking pulse for the first. And, from this modelling, we can get abundant understanding on how floating and sinking pulse can be caused. In the further study, we want to prove the suitability of this tonometric measurement based modelling with various studies including ultrasound measurement for the depth of pulsation in different EMI subjects.

• 한국철도학회논문집
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• 제7권1호
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• pp.65-69
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• 2004

In reference to this study, Part Ⅰ showed how the system respond to the harmonics originated from electric locomotives. That is, the system response to the harmonics was derived by computational algorithm with numerical formulas in theoretical aspects. However, Real catenary system has complex configuration of conductors and it is an important point that if we can consider the circuit element of catenary conductors as an uniformly distributed RLC element. Moreover, harmonic characteristics in electric locomotive depend on its operational modes. From these point of view, measurements of harmonics are performed for real railway power supply systems under the various operational modes, and spectrum and distortion analyses in measurement data are described.

• 대한전자공학회논문지
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• 제23권4호
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• pp.439-444
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• 1986

In this paper the PID-B self-tuner[1] is extended to allow a less abrupt response to set point or plant parameter changes and to control a nonminimum phase plant. The proposed extended PID/ST derived from the direct pole-placement PID/ST is obtained with the Bezout identity as the underlying design method. And its control gains are normalized by the integral control gain. Although the integral control gain is normalized to 1 in our scheme, the so-called "set point and derivative kick" can be avoided sufficiently by normalizing the measurement vector and set point.

• 대한기계학회논문집B
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• 제21권4호
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• pp.494-502
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• 1997

Experiments on corresponding jet flames with stagnant point diffusion flames have been carried out in initial injection periods. A compensated measurement of maximum flame temperature, which is based on the ion signal, has been employed to inspect flame responses to time-varying strain rates. The flame responses are obtained at two conditions for the slowly time-varying strain rate and the case of flame extinction, and analyzed to confirm similarity between a stagnant point diffusion flame and an evolving jet diffusion flame. Nonsteady effects are addressed via the comparison between several time scales. The time variation with low strain rates, in which illustrates the flame behavior of the upper branch far from extinction in the well-known S-curve, is confirmed to produce a quasi-steady flame response through the nonsteady experiments. The time variation with strain rates in the case of flame extinction indicates an unsteady effect of flame response. It is therefore found that the flame responses near jet tip depend on time histories of characterized strain rates in the developing process.

• 품질경영학회지
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• 제14권1호
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• pp.26-32
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• 1986

A class of multi-factor designs for estimating the slope of second order response surfaces is presented. For multi-factor designs the variance of the estimated slope at a point is a function of the direction of measurement of the slope and the design. If we average the variance over all possible directions, the averaged variance is only a function of the point and the design. By choice of design, it is possible to make this variance constant for all points equidistant from the design origin. This property is called "slope-rotatability over all directions", and the necessary and sufficient conditions for a design to have this property are given and proved. The class of design with this property is mainly discussed.