• Journal of Korean Society of Steel Construction
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• v.26 no.2
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• pp.105-118
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• 2014

The number of the deteriorated bridge has been sharply increased due to the increase in the bridge service period in Korea. Local corrosion problem of structural member can be occurred according to atmospheric corrosion environments based on the installation location of steel bridges. Especially, in case of the plate girder bridge, corrosion damage is concentrated on the web panel and stiffener at girder end. An asymmetrical shear resistant web section in the plate girder bridge can be caused from the local corrosion of the web panel, because local corrosion is not symmetrically occurred to the bridge. In this study, therefore, the shear buckling strength and behavior of a plate girder with asymmetrically corroded web panel was numerically evaluated using FE analysis, which was considering an aspect ratio and corrosion damage level of web panel. The shear buckling strength reduction of an asymmetrical shear resistant web panel was compared and evaluated according to corroded volume ratio for a web panel and for diagonal tension field of a web panel.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.5
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• pp.342-349
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• 2013

A damage imposed on an unmanned aerial vehicle changes the flight dynamic characteristics, and makes difficult for a conventional controller based on undamaged dynamics to stabilize the vehicle with damage. This paper presents a neural network based adaptive control method that guarantees stable control performance for an unmanned aerial vehicle even with damage on the main wing. Additionally, Pseudo Control Hedging (PCH) is combined to prevent control performance degradation by actuator characteristics. Asymmetric dynamic equations for an aircraft are chosen to describe motions of a vehicle with damage. Aerodynamic data from wind tunnel test for an undamaged model and a damaged model are used for numerical validation of the proposed control method. The numerical simulation has shown that the proposed control method has robust control performance in the presence of wing damage.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.831-832
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• 2006

본 논문에서는 Brushless DC Motors(이하 BLDC Motor이라 함)의 영구 자석의 오버행에 따른 진동, 소음 특성에 대하여 다루었다. 비대칭 오버행 구조에서는 Z축 방향 힘이 발생한다. 이는 베어링에 손상을 입힐 뿐 아니라 큰 노이즈와 진동을 유발시킨다. 따라서 진동과 소음의 감소를 위한 자석 오버행 효과 해석이 필수적이다. 본 논문에서는 비대칭 영구 자석 오버행 효과를 해석하고 BLDC Motor에서 발생하는 소음과 진동을 분석하였고 비대칭 영구 자석 오버행 효과를 고려하여 Z축 방향의 영향력을 계산하기 위하여 3차원 유한요소법(3D FEM)을 사용하였다.

• Journal of the Society of Naval Architects of Korea
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• v.48 no.3
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• pp.246-253
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• 2011

This paper presents estimation of deterministic damage extents and locations due to collision and grounding which are defined by ABS guideline and DNV ship rules. It is noted that the overall extents of damages from DNV are larger than those from ABS. Nonlinear FEAs are carried out to predict residual longitudinal strength of hull girder with asymmetric severe damages. The accuracy of the applied FEA procedure is proved by comparing FEA result with test result of a 1/3-scaled frigate. The investigated vessels are a VLCC and a large-sized bulker for which evenly distributed heeling angles from $0^{\circ}$(sagging) to $180^{\circ}$(hogging) by $30^{\circ}$ due to damage-induced flooding are taken into account. The reduction ratios of the ultimate residual strength for the damaged cases to those for the intact sagging case are shown. It is proved that the grounding damage case under DNV assumption reveals most critical the residual strength. The design formulas are presented to assure minimum residual ultimate moment after damage.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.25 no.4
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• pp.279-285
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• 2012

In this paper a computational method for a homogenized peridynamics description of unidirectional fiber-reinforced composites is presented. For these materials, dynamic brittle fracture and damage are simulated with the proposed peridynamic model. Compared with observations from dynamic experiments by Coker et al.(2001), the peridynamic computational model can reproduce various characteristics of dynamic fracture and supersonic or intersonic crack growth in asymmetrically loaded unidirectional fiber-reinforced composite plates. Also we analyze the same model in the symmetric loading condition and figure out that the asymmetric loading leads to a much higher propagation speed. Consistent results have been reported in the experiments.

• Journal of Korean Society of Steel Construction
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• v.28 no.6
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• pp.383-394
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• 2016

This study is intended to predict the seismic behavior of the down-scaled 3-story steel frame structures subjected to the real ground motion, and evaluate their structural damage through advanced finite element (FE) analysis results. The FE frame models are designed by considering the effect of the soft story. In addition, the effect of structural asymmetry is also taken into consideration during the nonlinear dynamic analyses. After observing the analysis results, it is reconfirmed that the damage of the steel frame building under the ground motion should be governed by the soft story column rather than the structural mass asymmetry.

• The Journal of Korea Assosiation for Disability and Oral Health
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• v.10 no.1
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• pp.22-25
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• 2014

Fibrous dysplasia(FD) is a benign fibro-ossifying disease in which fibrous tissue replaces normal bone and marrow. Craniofacial bones, including the maxilla and mandible, are commonly involved. A 7 year-old girl visited the clinic with a chief complaint of gingival swelling around the lower left primary molar. Mild bulging of the lower left periodontal tissue was observed. Not only the mandible, but also the maxilla, zygoma, sphenoid, and temporal bones were affected by FD. Permanent tooth germs were involved in the lesions and facial asymmetry was caused by lower left bone expansion. She was scheduled for a follow-up visit at the department of pediatric dentistry and oromaxillofacial surgery.

• Journal of the Korea Convergence Society
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• v.10 no.9
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• pp.63-68
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• 2019

The purpose of this study was to investigate the effect of hyper-extended knee and asymmetric standing posture on knee joint position and lower extremity muscle activity. Thirty-three voluntary participants participated and included sixty legs in the study. The sixty legs were divided into two groups: hyper-extended knee and normal group. The muscle activity and knee extension angle were measured. In the asymmetric standing posture, the knee joint extension angle and the muscle activity of the gastrocnemius were statistically significant between the normal group and the hyper-extended knee group. Based on the results, we confirmed that the asymmetric standing posture increases the hyper-extended knee. Therefore, it will contribute to the establishment of therapeutic guide for the subjects with hyper-extended knee to maintain the symmetrical standing posture, and future studies need to be conducted including the effects of the hip joint and ankle joints.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.8
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• pp.171-180
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• 2017

The purpose of this study is to determine an effective training method to improve sequela, since traumatic brain injury sequela is a major factor in determining the quality of life. Neurofeedback training was conducted for an adolescent who had experienced traumatic brain injury during his childhood and who had difficulty in cognitive learning and emotional aspects. The assessment of an adolescent was conducted using K-WAIS-IV intelligence test and QEEG brain wave analysis. In the neurofeedback training, T3 alpha wave compensation and T4 alpha wave inhibition training were performed 36 times for 30 minutes three times a week. In addition to the neurofeedback training, respiratory meditation was also made available to the adolescent. As a result, the adolescent showed a stable condition as indicated by taking a good sleep, reducing test anxiety, and satisfaction with final exam results. This study revealed the possibility for hidden physical and psychological problems arising due to childhood brain trauma. It has also recently been discovered that a more diverse set of tools can be found. In addition, these childhood traumatic brain injuries can be improved through brain training and meditation. The study finding is meaningful for its suggestion of a fusion method for developing mind and body therapy in terms of brain science.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.353-353
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• 2012

채널 도핑이 다른 비대칭 구조를 갖는 NMOSFET의 게이트 전압에 따른 Drain saturation current (IDSAT), maximum transconductance (GM) 및 threshold voltage (VT)와 같은 다양한 변수를 측정하였고 DAHC (Drain avalanche hot carriers) 스트레스에 따른 특성을 추출하였다. 전기적 특성은 반도체 파라미터 분석기를 사용하여 Probe system에서 진행되었다. 문턱전압은 Normal channel dopoing의 경우 0.67 V, High channel doping의 경우 0.74 V로 High channel doping된 소자가 상대적으로 높은 문턱전압을 보였다. Swing의 경우 Normal channel doping의 경우 87 mV/decade, high channel doping의 경우 92 mV/decade으로 High channel doping된 소자가 더 높은 Swing값을 보였다. 스트레스 인가 후 두 소자 모두 문턱전압이 증가하고 ON-current가 감소하였다. High channel doing된 소자의 경우 Normal channel doping된 소자보다 문턱전압의 증가율과 Current 감소율 측면 모두 스트레스에 더 민감하게 반응하였다. 문턱전압이 서로 다른 비대칭 NMOSFET의 핫 캐리어 특성을 비교, 분석결과 스트레스 인가에 따라 채널 도핑이 높아질수록 드레인과 게이트간의 더 높은 전계가 생겨 게이트 산화막과 Si/SiO2 계면의 손상이 더 발생하였다. 따라서 채널 도핑이 상대적으로 높은 트랜지스터가 핫 캐리어에 의한 계면 트랩 생성 비율이 더 높다는 것을 알 수 있다.