• International Journal of Highway Engineering
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• v.11 no.4
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• pp.49-58
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• 2009

Current sunshine regulations of our country, focused on common houses and general construction, are failing to reflect adequately the characteristics of roads and elevated structures. Besides, researches are chiefly being conducted on a pitch between common houses and its diverse effects, neglecting clearance between a road or elevated structure and a residential area, environmental elements brought on by structures, such as sunshine difficulty, and their resultant factors Therefore, this study, focused on the sunshine environment of elevated structures adjacent to a residential district, as part of all roads and elevated structures, looked over currently used clearance adequacy level and analyzed the characteristics of structures in relation to an angle of direction. Then, clearance ratio by heights was calculated through a pitch by characteristics of a structure. With a view to minimize the sunshine difficulty that might occur in the future construction, it aims to propose the basic data needed for calculating the minimum clearance, while emphasizing the necessity for institutional alignment on structures.

• Journal of Aerospace System Engineering
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• v.16 no.6
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• pp.106-113
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• 2022

The structural safety of the basic design model of the linear actuator for the individual blade pitch control of eVTOL personal aircraft was investigated. Stress analysis based on the finite element method was conducted, and the margin of safety was calculated to examine the structural safety under stall load conditions. Additionally, fatigue analysis was conducted to evaluate the fatigue life of the linear actuators under operating conditions. The load history with the blade pitch angle was calculated using multi-body dynamics analysis, and the static load analysis was used to obtain the stress distribution for the rated load. As a result, it was confirmed that the safety margins exceeded zero, and the fatigue lives of all linear actuator components exceeded 107 cycles, indicating a safe structural range.

• Korean Journal of Applied Biomechanics
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• v.27 no.3
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• pp.229-238
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• 2017

Objective: The purpose of this study was to identify the effects of taping therapy and inner arch support on pes planus lower extremity alignment and gait. Method: The study was conducted on 13 women in their 20s who had pes planus and no gait problems. Independent variables were the condition of wearing basic socks (S1) and the condition of wearing socks with taping therapy and inner arch support (S2). The dependent variables were resting calcaneal stance position (RCSP), plantar pressure distribution during gait, and underlying and medial longitudinal arch angle measured using radiography. Statistical analysis was performed using the Wilcoxon test with SPSS 23.0 for comparison of S1 and S2. Results: In the RCSP measurement, the angle range of S2 changed to normal. Meary's angle appeared to be less than the angle of S1, indicating alleviation of the degree of pes planus. The calcaneal pitch angle increased at S2 from that at S1. The plantar pressure distribution was divided into four areas (toe, forefoot, midfoot, and hindfoot). At S2, the maximum pressure increased in the toe and midfoot. The maximum force increased significantly in the toe and midfoot but decreased significantly in the forefoot and hindfoot. In addition, the contact area increased overall especially at the midfoot and hindfoot. Contact time decreased in the toe and forefoot, but increased in the midfoot and hindfoot. Conclusion: Taping therapy and inner arch support showed structural improvement of the pes planus. In addition, the force and pressure applied to the foot during walking are distributed evenly in the area of the sole, thus positively affecting walking.

• Journal of Korean Foot and Ankle Society
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• v.16 no.2
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• pp.101-107
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• 2012

Purpose: The aim of this study was to investigate the radiological characteristics of the osteoarthritis of the second metatarsophalangeal (MTP) and tarsometatarsal (TMT) joint. Materials and Methods: Between January 2002 and August 2010, 27 patients (33 feet) who had second metatarsal osteoarthritis (OA) were reviewed retrospectively. Group 1 was 14 patients (17 feet) with second MTP joint OA. Group 2 was 13 patients (16 feet) with second TMT joint OA. Group 3 was 24 patients (25 feet) had hallux valgus without second metatarsal (MT) OA as control. Weight bearing foot anteroposterior (AP) and lateral view were checked, and measured hallux valgus angle, metatarsus adductus angle (MAA), second MT functional length, first and second MT length by Hardy & Clapham method on AP view, angle of second MT with horizontal plane, calcaneal pitch, talo-first MT on lateral view. Results: On weight bearing foot AP view, second MT functional length of group 1, 2, 3 was 2.4 mm, -0.1 mm, 0.7 mm and MAA of group 1, 2, 3 was $17.7^{\circ}$, $17.7^{\circ}$, $14.5^{\circ}$. Second MT functional length of group 1 was longer than control group and it was statistically significant. MAA was significant different between group 1-3 and group 2-3. Angle of second MT with horizontal plane of group 2 was smaller than control group and it was statistically significant. Other radiographic parameters have no statistical significance. Conclusion: Group 1 has long functional length of second MT and group 2 has small angle of second MT with horizontal plane.

• Journal of Korean Foot and Ankle Society
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• v.9 no.1
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• pp.9-12
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• 2005

Purpose: This study is to compare the medial longitudinal arch between heel pain group and normal painless group. Materials and Methods: Heel pain group 242 feet and normal group 140 feet were evaluated through the radiographic images of standing foot-ankle lateral view. Four radiographic indices, talo-1stmetatarsal angle (TMA), calcaneal-1st metatarsal angle (CMA), calcaneal pitch angle (CPA), and arch ratio (AR), were used as well as BMI. Results: There was no difference between heel pain group and normal group in the TMA, CMA, CPA, and AR. But in the BMI, heel pain group showed $1.7\;kg/m^2$ (p=0.0002) higher than normal group. To eliminate the sexual error, male and female were evaluated separately. Male heel pain group showed 2.9 degrees more dorsiflexion (p=0.001) in the TMA, 3.1 degrees greater (p=0.007) in the CMA, 0.01 lower (p=0.028) in the AR, and $1.0\;kg/m^2$ greater (p=0.033) in the BMI than normal male group. There were no difference in the CPA. Female heel pain group showed 3.6 degree greater (p=0.035) in the CMA, and $1.9\;kg/m^2$ greater (p=0.002) in the BMI than normal female group. But other indices demonstrated no differences. Conclusion: talo-$1^{st}$ metatarsal angle, calcaneal-$1^{st}$ metatarsal angle and arch ratio were radiographic indices related with heel pain.

• JSTS:Journal of Semiconductor Technology and Science
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• v.14 no.3
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• pp.263-267
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• 2014

Super junction trench gate power MOSFETs have been receiving attention in terms of the trade-off between breakdown voltage and on-resistance. The vertical structure of super junction trench gate power MOSFETs allows the on-resistance to be reduced compared with conventional Trench Gate Power MOSFETs. The heat release of devices is also decreased with the reduction of on-resistance. In this paper, Lattice Temperature of two devices, Trench Gate Power MOSFET and Super junction trench gate power MOSFET, are compared in several temperature circumstance with the same Breakdown Voltage and Cell-pitch. The devices were designed by 100V Breakdown voltage and measured from 250K Lattice Temperature. We have tried to investigate how much temperature rise in the same condition. According as temperature gap between top of devices and bottom of devices, Super junction trench gate power MOSFET has a tendency to generate lower heat release than Trench Gate Power MOSFET. This means that Super junction trench gate power MOSFET is superior for wide-temperature range operation. When trench etching process is applied for making P-pillar region, trench angle factor is also important component. Depending on trench angle, characteristics of Super junction device are changed. In this paper, we focus temperature characteristic as changing trench angle factor. Consequently, Trench angle factor don't have a great effect on temperature change.

• Journal of radiological science and technology
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• v.42 no.4
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• pp.259-263
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• 2019

This study was purpose to compare image quality of Indirect digital radiography (IDR) system by using the International electro-technical commission standard(IEC 62220-1) which were applied to IEC in medical imaging. To evaluation the analysis of Modulation transfer function(MTF) measurements edge device each angle by using edge method. In this study, Aero (Konica, Japan) which is Indirect flat panel detector(FPD) was used, the size of image receptor matrix $1994{\times}2430$ which performed 12bit processing and pixel pitch is $175{\mu}m$. In IEC standard method were applied to each angle were compared. The results of shown as LSF at $2.0^{\circ}$ and $3.0^{\circ}$ angeles. Shape is constant and shows smooth shape. The amount of data seemed reasonable and 2.19 cycles/mm and 2.01 cycles/mm at a spatial frequency of $2.0^{\circ}$ and $3.0^{\circ}$ at an MTF value of 0.1. At an MTF value of 0.5, the spatial frequencies were $2.0^{\circ}$ and 1.11 cycles/mm and 0.93 cycles/mm at an angle of $3.0^{\circ}$. This study were to evaluate MTF by setting the each $2{\sim}3^{\circ}$ each angle and to suggest the quantitative methods of measuring by using IEC.

• Journal of Korean Foot and Ankle Society
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• v.28 no.2
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• pp.60-67
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• 2024

Purpose: Sinus tarsi syndrome (STS) is caused by various pathologies. However, the exact etiology of STS remains controversial. This study evaluated the imaging and arthroscopic findings of patients who underwent surgical treatment after conservative treatment for STS failed. Materials and Methods: Between December 2014 and August 2018, 20 patients (21 cases) who underwent surgical treatment for STS were included in the study. The clinical results were analyzed using the visual analog scale (VAS) and the American Orthopedic Foot and Ankle Society (AOFAS) ankle-hindfoot functional scale. The radiographic results were analyzed using Meary's angle, calcaneal pitch angle, and hindfoot alignment angle. The pathologic conditions of sinus tarsi were confirmed by magnetic resonance imaging (MRI) and subtalar arthroscopy. Synovitis, bone edema, and accessory anterolateral talar facet (AALTF) were evaluated on MRI. Synovial thickening, cartilage damage, interosseous talocalcaneal ligament (ITCL) and cervical ligament rupture, soft tissue impingement, AALTF, and accessory talar facet impingement (ATFI) were evaluated by subtalar arthroscopy. Results: The mean duration of symptoms was 28.7 months (4~120). All patients showed significant improvement in the VAS and AOFAS ankle-hindfoot scale. Significant improvements in hindfoot alignment angle and Meary's angle postoperatively were noted in patients who underwent medial displacement calcaneal osteotomy. MRI confirmed synovitis in all patients, AALTF in 19 cases (90.5%), and ATFI with bone edema in seven cases (33.3%). In subtalar arthroscopy, pathologic conditions were observed in the following order: synovitis in 21 cases (100%), AALTF in 20 cases (95.2%), ITCL partial rupture in nine cases (42.9%), and soft tissue impingement in seven cases (33.3%). All cases had two or more pathological conditions, and 15 (71.4%) had three or more. Conclusion: In cases of STS that do not respond to conservative treatment, a comprehensive examination of the lesions of the tarsal sinus and lesions around the subtalar joint is essential.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.7
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• pp.552-561
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• 2016

In this experimental study, the dynamic stability derivatives of a tailless lambda-shape UAV are estimated from time history data of aerodynamic moments measured from the internal balance while the test model is forced to oscillate at given frequencies and amplitudes. A 3-axis forced oscillation apparatus is designed to induce decoupled roll, yaw, pitch oscillations respectively. The results show that the roll damping derivatives remain stable at the entire range of angle of attack tested, whereas the pitch damping derivatives become unstable beyond $15^{\circ}$ angle of attack. The amplitude and frequency have little impact on roll damping derivatives while the smaller amplitude and frequency of oscillation improves the pitch stability. The yaw damping derivative values are fairly small as expected for a tailless configuration. The results indicate that the proposed methodology and test apparatus area valid for estimating the dynamic stability derivatives of a tailless UAV.

• 전자공학회논문지 IE
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• v.45 no.4
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• pp.11-18
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• 2008

This study is implementation of attitude control system(ACS - Attitude Control System). for a multi legs robot. This study designs H/W of Inertial Measurement Unit (IMU) and attitude control algorithm S/W. Compare performance with Mtx and MTx in order to verify action performance of this system after implementation, and will verify a system integrated IMU of a multi-legs robot. ACS uses Gyro and an accelerometer and an earth magnetism sensor, and it is a system controlling a roll, pitch angle attitude of an object. Generally, low price MEMS is difficult to calculate a correct situation of an object as an error occurs severely the Inertial sensor. This study implements IMU in order to develop ACS as use MEMS, accelerometer, Gyro sensor and earth magnetism sensor. Design algorithm each a roll, pitch, yaw attitude guaranteeing regular performance, and do poling in a system as include an attitude calculation program in an IMU system implemented. Mixed output of Gyro and an accelerometer, and recompensed a roll, pitch angle, and loaded in this study on a target platform in order to implement the ACS which guaranteed performance more than a continuously regular level, and operated by real time, and did porting, and verified.