• Progress in Medical Physics
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• v.18 no.3
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• pp.172-178
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• 2007

An ultrasonic bone densitometer has been developed by measuring speed of sound signal transmitted and received on the skin, not through the horizontal axis but through the vertical one in tissue. The SOS(speed of sound) method measuring the time difference between the ultrasound signals reflected from the both sides of surface of bone could produce more precise result compared with the BUA(broadband ultrasound attenuation) method measuring the frequency difference. Middle finger is selected to be the best measurement position in order to increase the accuracy, after due consideration that the thickness of flesh at the down part of thumb shows too much variation although the ratio of the receiving signal is higher than the other fingers. The measured value by using SOS method shows almost the same result as compared with the conventional DEXA method.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.33 no.6
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• pp.389-395
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• 2009

A specially designed flat plate was mounted vertically over the axial line in the wind tunnel of the Pusan National University. Strain balances were mounted in the trailing part of the plate to measure the skin friction drag over removable insertions of $0.55{\times}0.25m^2$ size. A set of the insertions was designed and manufactured: 3 mm thick polished metal surface and three compliant surfaces. The compliant surfaces were manufactured of a silicone rubber Silastic$^{(R)}$ S2 (Dow Corning company). To modify the viscoelastic properties of the rubber, its composition was varied: 90% rubber + 10% catalyst (standard), 92.5% + 7.5% (weak), 85% + 15% (strong). Modulus of elasticity and the loss factor were measured accurately for these materials in the frequency range from 40 Hz to 3 kHz. The aging of the materials (variation of their properties) for the period of one year was documented as well. Along with the drag measurement using the strain balance, velocity and pressure were measured for different coating. The strong compliant coating achieved 5% drag reduction within a velocity range $20{\sim}40$ m/s while standard and weak coatings increased drag reduction.

• Journal of Mechanical Science and Technology
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• v.14 no.11
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• pp.1305-1318
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• 2000

The local wall shear stress in transitional boundary layer was estimated from the near-wall mean velocity data using the principle of Computational Preston Tube Method(CPM). The previous DNS and experimental databases of transitional boundary layers were used to demonstrate the accuracy of the method and to provide the applicable range of wall unit y(sup)+. The skin friction coefficients predicted by the CPM agreed well with those from previous studies. To reexamine the applicability of CPM, near-wall hot-wire measurement were conducted in developing transitional boundary layers on a flat plate with different freestream turbulence intensities. The intermittency profiles across the transitional boundary layers were reasonably obtained from the conditional sampling technique. An empirical correlation between the representative intermittency near the wall and free parameter K$_1$of the extended wall function of CPM has been newly proposed using the present and other experimental data. The CPM has been verified as a useful tool to measure the wall shear stress in transitional boundary layer with reasonable accuracy.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.2
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• pp.175-181
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• 2007

The objective of this study was to develop formability evaluation techniques in order to apply aluminum sandwich panel for automotive body parts. For this purpose, newly adopting formability evaluation (using limit dome height and plane strain test) was carried out in order to secure the fundamental data for the measurement of sheet metal forming and the establishment of optimum forming conditions of the aluminum sandwich panel. The results showed that there were good agreements between the old formability evaluation method and the new method which was more simplified than that of old one. From the results of these formability evaluation, the formability of sandwich panel was higher than that of aluminum alloy sheet alone which was the skin component for the sandwich panel. Also, it was found that sandwich panel could reduce the weight and could have the same flexural rigidity simultaneously when it was compared to the automotive steel sheet.

• The Journal of the Korea Contents Association
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• v.10 no.6
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• pp.360-363
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• 2010

This study evaluated surface dose of treatment immobilization devices such as Themo-plastic, Vac-lock, Cotton and Plaster according to their electron energy. Using a linear accelerater, a plane parallel chamber was set up on 6Mev, 9Mev, 12Mev and 15Mev. A distance between a source and a surface was 100cm and a field size was 10cm*10cm. An incident angle was 0 degree and a radiation dose was 100MU. To decrease an error, the measurement repeated 3 times. The analysis reveals that the surface dose of Vac-lock was the highest and Themo-plastic, Plaster and Cotton were high in order.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.5
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• pp.992-999
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• 2009

The pulse transit time(PTT), which is determined by measuring the electrocardiogram(ECG) and pulse wave, gives comprehensive information about the cardiovascular system. However, a little movement of body and/or inaccurate pressure applied to skin during the measurement of pulse wave leads to acquire incorrect results. To overcome such problem, we developed an integrated sensor system which makes it possible to measure ECG, pressure pulse wave(PPW) and photoplethysmograph(PPG) at the same time. Futhermore, we implemented a new metal electrode which enables to continuously measure ECG. We verified that both integrated sensor system and new electrode provide useful effect.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.390.3-391
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• 2002

Nuclear-kappa B(NF-$\kappa$B) plays a role in the regulation of genes responsible for inflammatory and immune responses as well as growth control of cells. A cell-based assay system for guiding NF-KB activity was developed to determine the influence of activated NF-KB in human keratinocytes. It suggested that this system could be used to determine the quantitative measurement of NF-$\kappa$B activity in the human skin and allow the monitoring of anti-inflammatory agent for dermatological means from various environmental stimuli. (omitted)

• Journal of the Korea Safety Management & Science
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• v.17 no.1
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• pp.125-130
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• 2015

Techniques, using physical wedge filter and using dynamic wedge filter and FIF(Field in Field) and ISCT(Irregular Surface Compensating Technique), have been developed according to progress of radiation therapy of breast cancer. Measurement of dose was done to judge the usefulness of technique using three cases, non tissue loss after breast conserving operating and tissue loss after breast conserving operating and mastectomy. Dose indexes of breast tissue, CI (Conformity Index), HI (Homogeneity Index) and QOC (Quality of Coverage), dose index of skin, or dose indexes of lung, volume of 50 percent dose and 20 percent dose were estimated and compared. Using dynamic wedge filter is useful plan at non tissue loss allowing for high dose of lung. FIF and ISCT are useful plan at tissue loss. ISCT is useful plan at mastectomy. Henceforth, we need to apply to valid plan and body type and thorax size.

• Proceedings of the Korean Society of Computer Information Conference
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• 2013.07a
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• pp.359-360
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• 2013

본 연구에서는 외부 자극과 내적인 교감신경의 변화에 따라 나타나는 땀 반응으로 얻어진 생체신호를 다루었다. 즉, 땀 반응을 지칭하는 피부전도도를 측정할 수 있는 시스템과, 더불어 차량 운전시 혹은 운동 등의 동적 자극에 의한 영향을 최소화하여 교감신경에 의한 피부전도도의 신뢰도를 높일 수 있는 방안을 강구하였다. 기존의 두 개의 전극 간 리지스턴스(Resistance)를 측정하는 방식을 내부에서 분리된 한 개의 전극을 사용하여 신체적 움직임의 제한점을 해소하고 피부전도도로 나타난 생체신호가 외적인 움직임에 따른 영향인지 내적인 신경의 변화에 따른 영향인지를 추정할 수 있는 모듈을 개발하였다. 20명의 건강한 청년을 대상으로 피실험하여 기존의 생체신호 측정 장비인 MP-150의 EDA모듈과 동시 측정한 결과, 두 데이터가 약 88% 일치하는 것으로 확인하였다.

• The Journal of the Society of Korean Medicine Diagnostics
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• v.12 no.2
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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.