• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2007년도 학술대회 논문집 전문대학교육위원
• /
• pp.191-193
• /
• 2007

Pantograph sliding plate abrasion auto-detect system, one of the electric rail car auto-detecting devices, is a system that decides how much abrasion and when to replace without an inspector physically looking at the abrasion on the wet plate using machine vision, a cutting-edge technology. This paper covers the cause of deteriorating reliability that affects pantograph wet plate edge detection due to noise added to the video when it rains. In order to remove such noise, problems should be checked through Smoothing, Averaging mask and Median filter using filtering technique and stable edge detection without being affected by noise should be induced in video measurement used in machine vision technology.

• 한국철도학회논문집
• /
• 제12권3호
• /
• pp.364-369
• /
• 2009

Pantograph sliding plate abrasion auto-detect system, one of the electric rail car auto-detecting devices, is a system that decides how much abrasion and when to replace without an inspector physically looking at the abrasion on the wet plate using machine vision, a cutting-edge technology. This paper covers the cause of deteriorating reliability that affects pantograph wet plate edge detection doe to noise added to the video when it rains. In order to remove such noise, problems should be checked through Smoothing, Averaging mask and Median filter using filtering technique and stable edge detection without being affected by noise should be induced in video measurement used in machine vision technology.

• Journal of Welding and Joining
• /
• 제22권6호
• /
• pp.50-56
• /
• 2004

MlAB(magnetically impelled arc butt) welding is a sort of pressure welding method by melting two pipe sections with high speed rotating arc and upsetting two pipes in the axial direction. The electro-magnetic force, the driving force of the arc rotation, is generated by interaction of arc current and magnetic field induced from the magnetic flux generator in the welding system. In this study, an openable coil system for the generation of magnetic flux and a 3-dimensional numerical model for analyzing the electro-magnetic field were proposed. Through the fundamental numerical analyses, a magnetic concentrator was adopted for smoothing the magnetic flux density distribution in the circumferential direction. And then a series of numerical analysis were performed for investigating the effect of system parameters on the magnetic flux density distribution in the interested welding area.. Numerical quantitative analyses showed that magnetic flux density distribution generated from the proposed coil system is mainly dependent on the exciting current in the coil and the position of coil or concentrator from the pipe outer surface. And the gap between pipe ends and arc current are also considered as important factors on arc rotating behavior.

• 한국소음진동공학회논문집
• /
• 제16권3호
• /
• pp.255-262
• /
• 2006

Frequency spectrum using the conventional Fourier analysis gives adequate information about the dynamic characteristics of the slider air bearing for the linear and stationary cases. The intermittent contacts for the extremely low flying height, however, generate nonlinear and nonstationary vibration at the instant of contact. Nonlinear dynamic model should be developed to simulate the impulse response of the air bearing during slider-disk contact. Time-frequency analysis is widely used to investigate the nonstationary signal. Several time-frequency analysis methods are employed and compared for the slider vibration signal caused by the impact against an artificially induced scratch on the disk. The representative Wigner-Ville distribution leads to the severe interference problem by cross terms even though it gives good resolution both in time and frequency. The smoothing process improves the interference problem at the expense of resolution. In order to get the results with good resolution and little interference, the reassignment method is proposed. Among others the reassigned Gabor spectrogram shows the best resolution and readability with negligible interference.

• 디지털콘텐츠학회 논문지
• /
• 제5권4호
• /
• pp.289-294
• /
• 2004

영상분석을 하기 위하여 이용되는 많은 방법들은 기본적으로 잘 알려진 여러 가지 수학적인 이론에 기초해 전개 된다. 예로써 영상을 이변 함수에 대응시켜 기존의 미분 또는 편미분을 통한 경도 및 에너지 함수를 이용하거나 미분기하학적 측면에서 접평면 및 곡률을 사용하는 등과 같이 전통의 수학적 기법댐들이 적용되기도 한다. 그러나 국소적 변화를 효과적으로 분석하기 위해 사용되는 이러한 수학적 이론은 대상을 표현하는 함수가 충분히 연속적으로 변화하는 매우 부드러운 함수임을 가정하는 데에서 시작하게 된다. 그러므로 실제 자연의 형상 또는 현상을 구현하는 함수에 알려진 수학적 이론을 직접적으로 대입하므로 야기되는 여러 가지 불량문제를 종종 접하게 된다. 이러한 문제를 해결하기 위한 한 방법으로 본 논문에서는 보다 효율적으로 계산되고 광범위하게 적용될 수 있는 약미분을 정의하고 이를 해석하고자 하였다.

• 동의생리병리학회지
• /
• 제16권5호
• /
• pp.893-898
• /
• 2002

Citri Reticulatae Viride Pericarpium extract(CRVP) have been used in oriental medicine for many centuries as a therapeutic agent for smoothing the liver and regulating the circulation of qi, and promoting digestion and removing stagnated food. The effects of CRVP on the inhibition of brain damage in cerebral ischemia is not known. Therefore, this Study was designed to investigate the cerebral protective effects of CRVP on the transient cerebral ischemia using modern techniques, and further to provide the possibility of scientification of oriental medicine. The size of cerebral infarct size was measured by morphometry, and brain edema was measured by morphometry and brain water content determination. The results were a$ follows ; 1. Water fraction of CRVP was reduced infect area of rats brain slices which were subjected to a transient cerebral ischemia in a dose-dependent manner. 2. Methylene chloride fraction and hexane fraction of CRVP was significantly reduced infarct area of rats brain slices which were subjected to a transient cerebral ischemia in a dose-dependent manner. 3. Methylene chloride fraction and hexane fraction of CRVP was significantly reduced infarct volume of rats brain which was subjected to a transient cerebral ischemia in a dose-dependent manner. 4. Methylene Chloride fraction and hexane fraction of CRVP was significantly decreased brain edema induced by a transient cerebral ischemia in a dose-dependent manner. 5. Methylene chloride fraction and hexane fraction of CRVP was significantly decreased brain water content of rats which were subjected to a transient cerebral ischemia. It is suggested that CRVP has an anti-ischemic effect through the inhibition of brain damage in a transient cerebral ischemia, and that in future further development of main effective constituent in CRVP can provide a novel therapeutic strategy for cerebral ischemia.

• Journal of Acupuncture Research
• /
• 제20권5호
• /
• pp.133-150
• /
• 2003

Objective: Recently. many studies have showed the evidences of the effect of the Electro-acupuncture treatment through scientific. Methods : One of these methods is functional MRI. We performed electro-acupuncture on Zusanli(St36) and observed the change of brain activation using fMRI. Zusanli(St36) is located on the lateral side of the lower leg. 3 cun(寸) inferior to the Patella of the lower border. Theoretically and clinically. this point has been considered very important for gynecological disorders. spleen and stomach disorders. and psychological disorders. To see the effects of electro-acupuncture stimulation on Zusanli(St36). the experiment was carried out on twelve healthy volunteers. using the gradient echo sequence with the 3.0T whole-body fMRI system(ISOL). After the needle insertion on right Zusanli(St36). 2 Hz of electric stimulation was given for 30 seconds. repeated five times. with 30 seconds' intervals. The Image analysis including motion correction. talairach transformation, and smoothing was done with SPM99. Results ad conclusion : The electro-acupuncture stimulation on Zusanli(St36) activates Brodmann Area 6, 13, 2, 19, 21, 22, 39, 40, 38, 3which indicates the pathways of the electro-acupuncture stimulation on Zusanli(St36) and the possibility of the relationship of the electro-acupuncture stimulation on Zusanli(St36) with autonomic nervous system, internal organic system.

• 대한기계학회논문집B
• /
• 제22권6호
• /
• pp.725-733
• /
• 1998

The pressure fluctuation on the surface of a submerged body has been recognized as a dominant noise source. There have been many studies concerning the flow induced noise on a flat plate. However, the noise over an axisymmetric body has not been well reported. This paper addresses the way in which we have investigated the mechanism of noise generation due to an axisymmetric body. The associated experiments and signal processing methods are introduced. A 3-dimensional axisymmetric body whose length and diameter were 2 m and 10.4 cm, was prepared as a test specimen. The wall pressure on the surface of the body was measured in a large scale low noise wind tunnel at KIMM(Korea Institute of Machinery and Metals). To measure the wall pressure, we used two microphone arrays which were tangential and normal to the flow. Based on the measured signal, frequency-wavenumber spectrum which explains the structure of turbulence noise, was estimated. Tangential to the flow, there exists convective ridge at a relatively higher wavenumber region; this can cause spatial aliasing. To circumvent this problem, the cross spectrum was interpolated. The interpolation has been performed by unwrapping the phase and smoothing the cross spectrum. The phase unwrapping was done based on the Corcos model; the phase of cross spectrum decreases linearly with the distance between microphones. Aforementioned signal processings are possible by employing the experimental results that the estimated wavenumber spectrum quite resembles the Corcos model. We try to modify the Corcos model which is applicable to the flat plate, by altering the magnitude of cross spectrum to fit the experimental data more accurately. We proposed that this wavenumber spectrum model is suitable for the 3-dimensional axisymmetric body. Normal to the flow, there exists a little correlation between signals of different microphones. The circumferential wavenumber spectrum contains uniform power along the wavenumbers.

• Journal of Acupuncture Research
• /
• 제20권4호
• /
• pp.114-133
• /
• 2003

Objective : The meridian theory in oriental medicine explains that Sp9(Yinlingquan) has been considered very important for gynecological disorders, spleen and stomach disorders, and water metabolic disorders. Functional MRI is the best method of showing the evidences of the effect of the Electro-acupuncture treatment through scientific methods. On this supposition, Electro-acupuncture stimulation on Sp9(Yinlingquan) was carried out on six healthy volunteers, using the gradient echo sequence with the 3.0T whole-body MRI system(ISOL). Methods : Electro-acupuncture stimulation on Sp9(Yinlingquan), the experiment was carried out on six healthy volunteers, using the gradient echo sequence with the 3.0T whole-body MRI system(ISOL). After the needle insertion on right Sp9(Yinlingquan), 2Hz of electric stimulation was given for 30 seconds, repeated five times, with 30 seconds' intervals. The Image analysis including motion correction, talairach transformation, and smoothing was done using SPM99. Results : The electro-acupuncture stimulation on Sp9(Yinlingquan) activates Brodmann Area 13, 19, 22, 39, 40, 47 which may be the central pathways of the electro-acupuncture stimulation on Sp9(Yinlingquan). We also hypothesize that those brain areas may be directly or indirectly related with the mechanism of the effect of electro-acupuncture stimulation on Sp9(Yinlingquan).

• Journal of Acupuncture Research
• /
• 제20권4호
• /
• pp.66-84
• /
• 2003

Objectve : Recent stuides suggested that there is a strong correlation between acupuncture stimulation and its cortical activation. Another study showed that either positive or negative BOLD effects could be observed depending on anatomical structure in acupuncture. Methods : 1) Subjects and paradigms: Two separate stimulation paradigms were performed in this study. To see the effects of electro-acupuncture stimulation on K7(Fuliu), the experiment was carried out on six healthy volunteers, using the gradient echo sequence with the 3.0T whole-body MRI system(ISOL). After the needle insertion on right K7(Fuliu), 2 Hz of electric stimulation was given for 30 seconds, repeated five times, with 30 seconds' intervals. During the intervals while there was no electro-stimulation, the subjects performed motor task as a reference. The image analysis including motion correction, talairach transformation, and smoothing was done using SPM99. Results: The electro-acupuncture stimulation on K7(Fuliu) activated Brodmann's Areas of 9, 19, 23, 24, 31, 32, 39 which may be the central pathways of the electro-acupuncture stimulation on K7(Fuliu) and those brain areas may be related with the function of the electro-acupuncture stimulation on K7(Fuliu).