• 대한금속재료학회지
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• 제47권7호
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• pp.440-446
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• 2009

Co base superalloys have been widely used for the parts of gas turbine due to their excellent strength, thermal fatigue, oxidation resistance and weldability at high temperature. In this study, directional solidifications were carried out at various solidification rates, including $0.5{\sim}300{\mu}m/s$ in the Co base superalloy FSX-414. The cellular interface were formed at a low solidification rate, $1{\mu}m/s$, and the dendritic interface was found at higher solidification rates, $5{\sim}300{\mu}m/s$. As the spacing of dendrite structure decreased, the size and spacing of eutectics decreased. Dendrite arm spacing decreased with increasing solidification rates and temperature gradient. It was interesting to find the $M_{23}C_{6}$ eutectic microstructure formed between $\gamma$ dendrites. Composition analysis showed that Cr and W were segregated severely between the dendrites, which resulted in the formation of Cr-rich $M_{23}C_{6}$ and W-rich MC carbides.

• 복식문화연구
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• 제29권1호
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• pp.16-27
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• 2021

The purpose of this study was to identify the structure and characteristics for the reproduction of the armor in the Unified Silla period, and then reproduce and utilize it as a cultural content. In the armor reproduction project excavated from Jaemaejeong, Gyeongju. Jaemaejeong armor is consisting of Singap (身甲, body armor), Sanggap (裳甲, hip armor), and Sangbakgap (上膊甲, upper arm armor) at the time of excavation. Unlike the armor of the Three Kingdoms period, Singap and Sanggap are separated. Singap is Yangdangsik (裲襠式, side opening method) and Gyunggap (頸甲, gorget) was not unearthed, Sangbakgap was divided into a part that protects the left and right upper arms and a part that protects the chest, so that the unexcavated head and neck cover of the helmet can be protected to the shoulder. In addition, in the case of Chalgap (札甲, lamellar armor), the Oejungsik (外重式, folded from outside to inside) is mainly used, but it is peculiar that Naejungsik (內重式, folded from inside to outside) is used in Sangbakgap of Jaemaejeong armor. It is presumed that this was used as a method to ensure that the armor were closely attached to the human body. In order to design with the parade armor of Gochwidae in Gyeongju based on the reproduced Jaemaejeong armor, the designer's imagination and historical work of the times were involved due to the characteristics of performance costumes. Reproduced armor as a cultural content should be considered indispensable to simplify and lighten clothing suitable for performances based on the excavated historical armor.

• 셀메드
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• 제11권4호
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• pp.17.1-17.4
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• 2021

Episiotomy is the commonest obstetrics intervention in the world to reduce severe perineal injuries. Its prevalence is 43% to 100% in primiparous women in Asia. Further, worldwide approximately 10-95% of pregnant women undergo episiotomy incision during birth. Delay in wound healing probably increases the risk of wound infection, changes the muscular structure, and ultimately causes muscle tone loss. So, wound care is of specific significance to postnatal maternal outcomes. Hence, this case study aimed to evaluate the effect of Marham-i-Raal in episiotomy wound healing and pain relief. The study was conducted in eleven postpartum primi or multipara pregnant women aged between group 19 and 35 years with term gestational age, singleton pregnancy in a cephalic presentation who had a normal vaginal delivery with mediolateral episiotomy, without a perineal tear, and perineal hematoma. Externally, application of Marham-i-Raal 2g on episiotomy incisional wound, twice a day for 10 days was advised. Wound healing of episiotomy and pain intensity was assessed with REEDA ["redness, oedema, ecchymosis, discharge and approximation of the edges"] scoring and VAS scoring for pain intensity respectively. At one hour (baseline), the REEDA mean score of eleven patients was 3.90±1.04 whereas on day 7-10 it was 0.18±0.40 with statistically significant difference (p<0.001). The VAS mean score at one hour was 6.90±1.22 whereas on day 7-10 it was 0.72±0.78 with a statistically significant difference (p<0.001). Marham-i-Raal would be effective in episiotomy wound healing and reducing pain intensity. Further, randomized double-blind controlled trials in large sample size are recommended.

• 한국정보기술학회 영문논문지
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• 제10권1호
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• pp.71-83
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• 2020

In this paper, we propose a system that can detect the shape of a hand at high speed using an FPGA. The hand-shape detection system is designed using Verilog HDL, a hardware language that can process in parallel instead of sequentially running C++ because real-time processing is important. There are several methods for hand gesture recognition, but the image processing method is used. Since the human eye is sensitive to brightness, the YCbCr color model was selected among various color expression methods to obtain a result that is less affected by lighting. For the CbCr elements, only the components corresponding to the skin color are filtered out from the input image by utilizing the restriction conditions. In order to increase the speed of object recognition, a median filter that removes noise present in the input image is used, and this filter is designed to allow comparison of values and extraction of intermediate values at the same time to reduce the amount of computation. For parallel processing, it is designed to locate the centerline of the hand during scanning and sorting the stored data. The line with the highest count is selected as the center line of the hand, and the size of the hand is determined based on the count, and the hand and arm parts are separated. The designed hardware circuit satisfied the target operating frequency and the number of gates.

• Wind and Structures
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• 제34권2호
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• pp.199-213
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• 2022

The current study investigates the dynamic effects in the tornado-structure response of an aeroelastic self-supported lattice transmission tower model tested under laboratory simulated tornado-like vortices. The aeroelastic model is designed for a geometric scale of 1:65 and tested under scaled down tornadoes in the Wind Engineering, Energy and Environment (WindEEE) Research Institute. The simulated tornadoes have a similar length scale of 1:65 compared to the full-scale. An extensive experimental parametric study is conducted by offsetting the stationary tornado center with respect to the aeroelastic model. Such aeroelastic testing of a transmission tower under laboratory tornadoes is not reported in the literature. A multiaxial load cell is mounted underneath the base plate to measure the base shear forces and overturning moments applied to the model in three perpendicular directions. A three-axis accelerometer is mounted at the level of the second cross-arm to measure response accelerations to evaluate the natural frequencies through a free-vibration test. Radial, tangential, and axial velocity components of the tornado wind field are measured using cobra probes. Sensitivity analyses are conducted to assess the variation of the structural dynamic response associated with the location of the tornado relative to the lattice transmission tower. Three different layouts representing the change in the orientation of the tower model relative to the components of the tornado-induced loads are considered. The structural responses of the aeroelastic model in terms of base shear forces, overturning moments, and lateral accelerations are measured. The results are utilized to understand the dynamic response of self-supported transmission towers to the tornado-induced loads.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2023년도 춘계학술대회
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• pp.151-151
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• 2023

무인잠수정의 정밀한 제어 시스템 개발에는 높은 정도의 조종 유체력 미계수 추정이 필수적이다. 전통적으로 조종 미계수는 모형을 이용한 실험(사항, Planar Motion Mechanism, Rotating Arm)과 단순한 이론과 경험을 기반으로 개발된 경험식으로 추정하였다. 그러나 최근 크게 향상된 계산기 성능의 발전은 전산유체역학의 적용성을 크게 확대하였다. 따라서 본 논문에서는 만타형 무인잠수정의 조종 유체력 미계수 추정을 위한 전산유체역학 해석기법을 개발하고자 한다. 특히, 수직 동적 PMM 시험법에 관한 해석기법을 중점적으로 개발한다. 개발된 기법을 이용하여 만타형 무인 잠수정의 6자유도 유체력을 추정하고 그 결과를 실험과 비교하여 개발된 기법을 검증한다. 본 연구에서는 1/6 모형을 이용한다. 수치해석기법 개발은 RASN 기반 상용 해석소프트웨어인 STAR-CCM+를 사용하였다.

• 한국운동역학회지
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• 제34권2호
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• pp.45-52
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• 2024

Objective: The purpose of this study was to measure the morphological characteristics of the foot and biomechanical variables of the lower extremity joints during vertical jump and investigate the relationship between foot morphology and biomechanics of vertical jump. Method: 24 men in their 20s (age: 22.42 ± 1.41 yrs, height: 173.37 ± 4.61 cm, weight: 72.02 ± 6.21 kg, foot length: 251.70 ± 8.68 mm) participated in the study. Morphological characteristics of the foot included the length of the first toe, the length of the second toe, and the horizontal length from the center of ankle joint to the achilles tendon (Plantar Flexion Moment Arm [PFMA]). Biomechanical variables were measured for plantar flexor strength of the ankle joint and peak angular velocity, moment, and power of the lower extremity joint during vertical jump. Results: There was a significant correlation between the length of the first toe and plantar flexion strength at 30°/s [r=.440, p=.016], the angular velocity of the metatarsophalangeal [MTP] joint [r=-.369, p=.038] while significant correlations between PFMA and the angular velocities of the knee joint [r=.369, p=.038] and ankle joint [r=.420, p=.021] were found. There were also significant correlations between the length of the first toe and the maximum moment of the hip joint [r=.379, p=.034], and the length of the second toe and the power of the hip joint [r=-.391, p=.029]. Finally, significant correlations between PFMA and the power of the ankle joint [r=.424, p=.019] and MTP joint [r=.367, p=.039] were found. Conclusion: Based on the results of this study, the length of the toe and PFMA would be related to the function of the lower extremity joint. Therefore, this should be considered when designing the functional structure of a shoe. Furthermore, this relationship can be applied to intensive training for the plantar flexors and toe flexors to improve power in athletic performance.

• 감성과학
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• 제20권3호
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• pp.141-150
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• 2017

본 연구에서는 E-textile 기반 신축성 센서의 모양과 부착 위치가 동작 센싱 성능에 미치는 영향을 분석하고, 이를 통해 인체 동작 센싱에 가장 적합한 의복 구조 요건을 규명하고자 하였다. 실험 대상 아동에게 센서의 모양과 부착 위치에 따라 조작된 실험복을 착의시킨 후 60 deg/sec의 속도로, $60^{\circ}$, $90^{\circ}$, $120^{\circ}$의 동작 각도별로 팔과 다리의 굽힘, 폄 동작 의한 직물 센서의 신장과 수축에 따른 전압의 변화량을 측정하였으며, 가속도 센서를 함께 부착하여 동작의 일치도를 검증하였다. 또한 아동의 모형 팔과 다리를 제작하여 이를 대상으로 동일한 실험을 수행함으로써 인체의 팔, 다리의 동작 실험 결과와 비교하였다. 분석 결과 센서의 모양에서는 모형 대상 실험과 아동 대상 실험 모두에서 보트형의 센서 보다 장방형의 센서가 더 균일하고 안정적인 경향을 보여 재현성과 신뢰성이 높은 것으로 나타났다. 센서의 부착 위치는 모형 대상 실험에서는 팔꿈치와 무릎의 관절부로부터 4 cm 아래 지점에 부착된 경우, 아동 대상 실험에서는 팔꿈치와 무릎의 관절부에 위치했을 때 재현성과 신뢰성이 더 높았다. 본 연구에서는 아동의 사지 동작 측정에 적합한 센서를 개발하고 동작 센싱에 적합한 센서의 모양과 부착 위치의 조건을 분석하였으며, 의복에 통합된 유연한 직물 센서를 활용하여 인체 부위별 동작 센싱이 가능하다는 것을 규명하였다.

• Journal of Korean Neurosurgical Society
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• 제30권9호
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• pp.1086-1093
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• 2001

Object : With the recent variable treatment modalities and the development of microsurgical techniques, outcomes of surgical and medical management of aneurysm have shown much progress in the last 10 years. However, the management of posterior circulation aneurysm is still a debatable due to its difficulty in limited surgical approach, complicated anatomical structure and many small perforators to vital structure. The purpose of this study is to compare the results of clinical manifestation and outcome of surgery with respect to anterior and posterior circulation aneurysms. Material and Methods : We evaluated the 33 patients with PCAs(posterior circulation aneurysm) and 359 patients with ACAs(anterior circulation aneurysm) treated between 1994 and 1999, retrospectively. Results : Posterior circulation aneurysms showed higher tendency(5 cases, 14.7%) to have unusual shapes, such as dissecting or fusiform compared with anterior circulation aneurysm(15 cases, 4.2%). There were more multiple aneurysms in posterior circulation aneurysm(8 cases, 26.5%) than anterior circulation aneurysm(59 cases, 16.2%). The number of patients with Hunt-Hess grade III or IV on admission were 91(25.3%) in anterior circulation aneurysms, and 14(42.4%) in posterior circulation aneurysms. There were higher incidences of vasospasm and acute hydrocephalus in patients with posterior circulation aneurysm. In cases of anterior circulation aneurysm, neck clipping was possible in 97%. But, in posterior circulation aneurysm, neck clipping was possible only in 67.7% of each. Two hundred forty four cases(85.0%) of all anterior circulation aneurysms and 22 cases(78.6%) of all posterior circulation aneurysms showed good recovery(GR) or moderate disability(MD). The postoperative mortality rates of anterior and posterior circulation aneurysms were 4.9% and 10.7%, respectively. Conclusion : These results indicate that there exist substantial differences with respect to that there were few difference in the aspect of surgery and management outcome between posterior circulation aneurysms and anterior circulation aneurysms.

• 한국산학기술학회논문지
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• 제22권3호
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• pp.492-498
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• 2021

본 논문에서는 액체 소금물을 전도체로써 이용한 평면형 투명 안테나의 구현 가능성을 연구 하였다. 소금물을 이용한 투명 안테나 구현의 가장 큰 이유는 기존 고체 투명전극의 광투과도 indium tin oxide (ITO:> 73%) 또는 multi-layer films (MLF: > 78%) 대비 높은 소금물의 광투과도 (> 95% @ 40 ppt)에 있다. 제안된 다이폴안테나의 양쪽 팔의 소금물 층을 평면형으로 고정하기 위해 투명 아크릴(��r = 2.61, tan�� = 0.01, OTav > 90 %)을 사용하였으며, 소금물의 표면장력을 이용하여 (ASA: 아크릴/소금물/아크릴) 형태의 평면형 ASA층으로 구현 하였다. 전기적, 광학적으로 ASA 전도체 구조를 분석하기 위해, 표면장력을 통한 평면형 구조 유지 시, 소금물 두께에 따른 면저항과 광투과도를 분석 하였다. 소금물을 이용한 투명 평면형 다이폴 안테나는 UHF(Ultra high frequency) 대역(470-771 MHz)에서 1.72 dBi의 평균 방사이득 및 74 %의 방사효율을 가지며, 향후 소금물을 이용한 평면형 투명안테나로써의 활용 가능성을 확인 하였다.