• Progress in Medical Physics
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• v.14 no.2
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• pp.131-140
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• 2003

As the importance of accuracy in measurings of 3-D anatomical structures continues to be stressed, an objective and quantitative of assessing image quality and accuracy of 3-D volume-rendered images is required. The purpose of this study was to evaluate the quantitative accuracy of 3-D rendered images obtained with MDCT, scanned at various scanning parameters (scan modes, slice thicknesses and reconstruction slice thickness). Twelve clinically significant points that play an important role for the craniofacial bone in plastic surgery and dentistry were marked on the surface of a dry human skull. The direct distances between the reference points were defined as gold standards to assess the measuring errors of 3-D images. Then, we scanned the specimen with acquisition parameters of 300 mA, In kVp, and 1.0 sec scan time in axial and helical scan modes (pitch 3:1 and 6:1) at 1,25 mm, 2.50 mm, 3.75 mm and 5.00 mm slice thicknesses. We performed 3-D visualizations and distance measurements with volumetric analysis software and statistically evaluated the quantitative accuracy of distance measurements. The accuracy of distance measurements on the 3-D images acquired with 1.25, 2.50, 3,75 and 5.00 mm slice thickness were 48%, 33%, 23%, 14%, respectively, and those of the reconstructed 1.25 mm were 53%, 41%, 43%, 36% respectively. Meanwhile, there were insignificant statistical differences (P-value<0.05) in the accuracy of the distance measurements of 3-D images reconstructed with 1.25 mm thickness. In conclusion, slice thickness, rather than scan mode, influenced the quantitative accuracy of distance measurements in 3-D rendered images with MDCT. The quantitative analysis of distance measurements may be a useful tool for evaluating the accuracy of 3-D rendered images used in diagnosis, surgical planning, and radiotherapeutic treatment.

• Proceedings of the SCSK Conference
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• 1996.07a
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• pp.52-67
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• 1996

새로운 노화방지 물질로 개발한 3-APPA가 노화에 의해 야기되는 여러 변화들, 특히 세포 증식, 유전자 수준 및 단백질 수준에서의 collagen의 생합성 변화, 면역조직화학염색을 이용한 collagen 생합성의 변화등을 세포배양 및 동물실험을 통하여 측정하였다. MTT assay를 이용한 인체 피부 섬유아세포의 증식 실험에서 3-APPA는 무처치군에 비교해서 최고 2배의 섬유아세포 증식 효능을 나타내었으며, $^3$[H]-proline incorporation 방법을 이용한 단층세포 배양 및 3차원 dermal equivalent 섬유아세포 배양에서 무처치군 및 vitamin C 처리군에 비해 최고 1.5배의 collagen 생합성 증가를 나타내었다. 그러나 type I alpha-procollagen mRNA expression에는 영향을 미치지 않는 것으로 나타났다. H&E 염색을 이용한 hairless mice의 피부에 대한 형태학적 변화 및 type I pM procollagen antibody를 이용한 면역조직화학염색에서, 3-APPA는 collagen 생합성을 증가시키는 것으로 나타났다. 이상의 결과에서 3-APPA는 섬유아세포 배양 및 hairless mouse를 이용한 실험에서 피부 섬유아세포 증식을 촉진시키며 collagen 생합성을 증가시켜 피부노화를 억제 할 수 있는 물질임을 밝혔다.

• Proceedings of the ESK Conference
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• 1997.04a
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• pp.85-89
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• 1997

We used a three-dimensional motion capture method to measure the grasping reach of Korean. This method was applied well to the grasping reach measurement with low measurement error and high efficiency. We measured the grasping reach of 29 males and 21 females at the different height from seat reference level; -10, 0, 30, 60, and 90cm. The grasping reach data were summarized at each 15 .deg. in polar corrdinates to compare with the former researches. If the number of subjects increases in the supplement research, the grasping reach data will be used in the ergonomic design of the driver's cabin or workstations in industry.

• Proceedings of the Korea Contents Association Conference
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• 2011.05a
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• pp.269-270
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• 2011

숄더백과 백팩을 멜 때의 척추자세의 변화양상이 각각 다름에도 불구하고 백팩에 비해 숄더백을 멜 때의 인체자세 변화에 대한 생체역학적 연구는 부족하다. 본 연구의 목적은 숄더백을 멜 때 무게증가에 따라 몸통자세의 변화양상을 분석하는 것이다. 몸통자세의 변화를 측정하기 위하여 3차원 동작분석시스템을 사용하였고, 가방무게는 3가지 조건(5, 10, 15 kg)과 통제조건(0 kg)으로 정하였다. 실험 결과 몸통전방기울기와 몸통측방기울기는 무게가 증가함에 따라 유의하게 증가하였다. 요추의 수평면상 축회전이 무게가 증가함에 따라 반시계 방향으로 유의하게 증가하였다. 흉추에서는 무게 증가에 따른 움직임의 변화가 유의하게 나타나지 않았다. 이러한 결과는 숄더백을 멜 때 척추자세 변화가 요추와 흉추에서 다르게 나타남을 의미한다. 본 연구에서 제시된 생체정보 분석기술은 일상생활에서의 인체정보 컨텐츠를 축적하는데 매우 유용할 것으로 기대 된다.

• Journal of the Korean Society of Radiology
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• v.11 no.6
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• pp.467-473
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• 2017

Using Digital Imaging and Communications in Medicine(DICOM) and a 3D medical imaging program, the characteristics of the external auditory canal(EAC) were compared. Using images of the ears of 63 different male and female subjects of varying age, this study measured and compared EAC transverse axis lengths, internal diameter circumferences, and upper and lower curvature angles. The findings of the study indicated differences in EAC shapes according not only to age and sex but also to the left and right of the same subject. A comparison between the sexes of the subjects (35 males and 28 females) indicated that, on average, the length of the EAC was 4.75mm longer in males. Based on the lower curvature angle, the interior side of the diameter circumference of the EAC was found to be reduced on average by 37.2% compared to the exterior side. Although the upper curvature angle was on average $25.7^{\circ}$ larger than the lower curvature angle, 4 subjects showed a larger lower curvature angle and large differences between the upper and lower curvature angles were observed in 8 subjects of the younger age group (4~14 years old). This indicated changes in EAC curvature shapes during growth. This study presents a method to raise safety and precision by comparing direct measurements taken through physical means and indirect measurements acquired from existing ear samples. This was possible due to technological developments in which 3D medical image representation technology creates images close to reality, and, through further development, this method is expected to be used for standardization research of EAC shapes.

• Progress in Medical Physics
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• v.23 no.3
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• pp.162-168
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• 2012

In proton therapy, in vivo dose verification is one of the most important parts to fully utilize characteristics of proton dose distribution concentrating high dose with steep gradient and guarantee the patient safety. Currently, in order to image the proton dose distribution, a prompt gamma distribution detection system, which consists of an array of multiple CsI(Tl) scintillation detectors in the vertical direction, a collimator, and a multi-channel DAQ system is under development. In the present study, the optimal design of prompt gamma distribution detection system was studied by Monte Carlo simulations using the MCNPX code. For effective measurement of high-energy prompt gammas with enough imaging resolution, the dimensions of the CsI(Tl) scintillator was determined to be $6{\times}6{\times}50mm^3$. In order to maximize the detection efficiency for prompt gammas while minimizing the contribution of background gammas generated by neutron captures, the hole size and the length of the collimator were optimized as $6{\times}6mm^2$ and 150 mm, respectively. Finally, the performance of the detection system optimized in the present study was predicted by Monte Carlo simulations for a 150 MeV proton beam. Our result shows that the detection system in the optimal dimensions can effectively measure the 2D prompt gamma distribution and determine the beam range within 1 mm errors for 150 MeV proton beam.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.220-223
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• 1997

Moire topography method is a well-known non-contacting 3-D measuement method. Recently, the automatic 3-D measurement by moire topography has been required since the method was frequently applied to the engineering and medical fields. 3-D measurement using projection moire topography is very attractive because of it's high measuring speed and high sensitivity. In this paper, using two-wavelength method of projection moire topography tested to measuring object with the 2x-ambiguity problem. Experimental results prove that the proposed scheme is capable of finding absolute fringe orders, so that the 2x-ambiguity problem can be effectively overcome so as to treat large step discontinuities in measured objects.

• Science of Emotion and Sensibility
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• v.14 no.1
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• pp.39-48
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• 2011

There still is a limitation in the usage of 3D clothes model in the production line due to the lack of compatibility between 3D modeling software, and its accurate 2D pattern making software, especially for free formed dress with tight fitted zone and draped part. In this study, obstacles in the 3D direct dress design process was overcome by solving the compatibility among each step of 3D virtual design process as well as adopting 3D-2D direct pattern development program called 2C-AN. Efficacy of making 2D pattern from 3D dress design using 2C-AN program developed by the authors was examined during the course of actual dress making process. Accurate ease over the fitted dress part was examined by 3D scanning technology, and the actual appearance of the draped part was compared with the simulation image of dress model. It was confirmed that the entire 3D design process and direct 2D pattern development proposed in this study was accurate enough to use in the 3D design process.

• Journal of the Korean Society of Clothing and Textiles
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• v.36 no.4
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• pp.456-471
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• 2012

This study creates a method with more scientific patterns for use in designing golfwear slacks patterns that better reflect the unique characteristics of body types for elderly women aged 60 or older. This study investigates (when designing human-engineering golfwear slacks for elderly women) the body types of elderly women and design slacks patterns suitable for golf actions in order to design golfwear slacks that show excellence in function and aesthetics as well as for exercise and everyday wear conditions. The study indicated that "total crotch length" was the design element for most considerations when manufacturing golf slacks. A survey on the production of golf slacks for elderly women aged 60 or older showed that the 6 firms participating have not produced an exclusive product for women 60 years of age or older and have only manufactured an enlarged size up to 85. All 6 firms participating replied "No" two the question "Do you produce in consideration of the body types of women over 60 years of age?" Polyester-polyurethane composites were the most widely used (among golf slacks materials) as spring-autumn applications.

• Journal of Biomedical Engineering Research
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• v.25 no.4
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• pp.269-275
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• 2004

Different biological tissues have different values of electrical resistivity. In EIT (electrical impedance tomography), we try to provide cross-sectional images of a resistivity distribution inside an electrically conducting subject such as the human body mainly for functional imaging. However, it is well known that the image reconstruction problem in EIT is ill-posed and the quality of a reconstructed image highly depends on the measurement error. This requires us to develop a high-performance EIT system. In this paper, we describe the development of a 16-channel digital EIT system including a single constant current source, 16 voltmeters, main controller, and PC. The system was designed and implemented using the FPGA-based digital technology. The current source injects 50KHz sinusoidal current with the THD (total harmonic distortion) of 0.0029% and amplitude stability of 0.022%. The single current source and switching circuit reduce the measurement error associated with imperfect matching of multiple current sources at the expense of a reduced data acquisition time. The digital voltmeter measuring the induced boundary voltage consists of a differential amplifier, ADC, and FPGA (field programmable gate array). The digital phase-sensitive demodulation technique was implemented in the voltmeter to maximize the SNR (signal-to-noise ratio). Experimental results of 16-channel digital voltmeters showed the SNR of 90dB. We used the developed EIT system to reconstruct resistivity images of a saline phantom containing banana objects. Based on the results, we suggest future improvements for a 64-channel muff-frequency EIT system for three-dimensional dynamic imaging of bio-impedance distributions inside the human body.