• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.317-318
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• 2007

휴머노이드 로봇이 인간에게 필요한 다양한 서비스를 제공하기 위해서는 정해진 동작이 아닌 상황에 따른 다양한 동작이 요구된다. 특히 보행에 있어서는 회전각도 보폭 등이 상황에 따라 변경이 가능해야 한다. 이에 따라 로봇에게 필요한 다양한 보행 궤적을 생성하기 위해서는 보행궤적의 생성과 안정성 판별을 위한 ZMP(Zero Moment Point), COG(Center Of Gravity)등의 생성을 위한 시뮬레이터가 필요하게 된다. 본 논문에서는 성행 연구를 통해 개발된 시뮬레이터 프로그램의 단점을 분석하고 보완하여, 보폭 및 회전 각도가 자유로운 회전 보행의 생성이 가능한 시뮬레이터 프로그램을 구현하였다. 그리고 구현된 시뮬레이터 프로그램을 사용하여 생성된 궤적 파일을 동역학 해석 프로그램인 NASTRAN을 이용 시뮬레이터를 검증한다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.2
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• pp.23-29
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• 2015

The baby-step giant-step algorithm seeks b in a discrete logarithm problem when a,c,p of $a^b{\equiv}c$(mod p) are already given. It does so by dividing p by m block of $m={\lceil}{\sqrt{p}}{\rceil}$ length and letting one giant walk straight toward $a^0$ with constant m strides in search for b. In this paper, I basically reduce $m={\lceil}{\sqrt{p}}{\rceil}$ to p/l, $a^l$ > p and replace a giant with an adult who is designed to walk straight with constant l strides. I also extend the algorithm to allow $2^k$ adults to walk simultaneously. As a consequence, the proposed algorithm quarters the execution time of the basic adult-walk method when applied to $2^k$, (k=2) in the range of $1{\leq}b{\leq}p-1$. In conclusion, the proposed algorithm greatly shorten the step number of baby-step giant-step.

• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.5
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• pp.194-202
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• 2006

In the present study, stiffness prediction methodologies for flat-plate structures were evaluated in comparison with the experimental results on the full-scale slab-column connections of flat-plate structures. The methodologies are as follows: the methodology proposed by Jacob S. Grossman and the methodology proposed by Choi & Song. The former does not predict the stiffness change of the slab-column connection due to the change in the column section shape and the latter overestimates the stiffness when edge length of the column section in the loading direction is long. In the present study, the equation to calculate the effective width of slabs was modified to reflect the effect of the change in the column section shape.

• Journal of Life Science
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• v.19 no.9
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• pp.1299-1303
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• 2009

The purpose of this study was to analyse the gait characteristics of stroke patients walking on a Zebris system, through quantitative three-dimensional biomechanical analysis. They underwent a continuous rehabilitation training program (RTP). A comparison was made between 3 month and 6 month RTP participants. Their ages were between 60 and 65. The data were analyzed by t-test. The result of comparative analysis of the two groups can be summarized as below. Temporal-spatial data, sagittal plane angular kinematics data, and peak ground reaction force and max pressure data showed that there were no significant differences between the 3 month RTP group and the 6month RTP group (Table 2, Table3, Table 4). It can be suggested that patients with hemiplegia after stroke can improve their walking function through continuous RTP participation.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.16 no.4
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• pp.439-450
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• 2003

Flat plate system has been adopted in many buildings constructed recently because of the advantage of reduced floor heights to meet the economical and architectural demands. Structural engineers commonly use the effective beam width model(EBWM) in practical engineering for the analysis of flat plate structures. However, in many cases, when it is difficult to use the EBWM, it is necessary to use a refined finite element model for an accurate analysis. But it would take significant amount of computational time and memory if the entire building structure was subdivided with finer meshes. An efficient analytical method is proposed in this study to obtain accurate results in significantly reduced computational time. The proposed method employs super elements developed using the matrix condensation technique and fictitious beams are used in the development of super elements to enforce the compatibility at the interfaces of super elements. The stiffness degradation of flat plate system considered in the EBWM was taken into account by reducing the elastic modulus of floor slabs in this study. Static and dynamic analyses of example structures were performed and the efficiency and accuracy of the proposed method were verified by comparing the results with those of the refined finite element model and the EBWM.

• Electric Engineers Magazine
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• v.195 no.11
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• pp.30-34
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• 1998

가공송전선의 접지는 주로 내뢰설계에 그 목적이 있지만 전력계통의 안정도, 전력계통의 고장검출과 철탑주변의 접촉전압 및 보폭전압에도 영향을 미치고 있는 것이 사실이다. 특히 전력계통에서 지락사고가 발생할 경우 지락전류가 송전철탑에 시설되어 있는 가공지선과 대지로 분류하는 정도에 따라 지락지점에서의 대지전위 상승이 크게 좌우된다.

• Journal of the Korean Society of Physical Medicine
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• v.7 no.3
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• pp.379-385
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• 2012

연구목적 : 본 연구의 목적은 태권도 프로그램이 노인의 균형능력에 어떠한 영향을 미치는지에 대해 알아보는 것이다. 연구방법 : 대상자는 본 연구에 대해 설명을 들은 후 자원한자로서 65세 이상의 노인이었다. 실험군은 태권도 프로그램 그룹으로서 17명이었다. 태권도 프로그램을 주3회씩 6주간 시행하였고 모든 대상자의 균형능력을 평가하기 위하여 BPM, GAITrite, Berg 균형척도를 실험전후로 평가하여 자료를 수집하였다. 수집된 자료는 SPSS 14.0으로 대응표본 t-test를 사용하여 유의수준 ${\alpha}$=.05에서 통계 처리 하였다. 연구결과 : 태권도 프로그램을 시행한 결과 프로그램 실행 전에 비해 오른쪽 활보폭, 왼쪽 보폭, 왼쪽 활보폭, 버그 균형척도에서 통계적으로 유의한 증가를 나타내었다. 그리고 최대 동요속도, 동요거리, 오른쪽 기저 지지면, 오른쪽 양하지 지지기, 왼쪽 기저지지면, 왼쪽 양하지 지지기에서 통계적으로 유의한 감소가 있었다. 결론 : 태권도 프로그램을 시행한 결과 오른쪽 활보폭, 왼쪽 보폭, 왼쪽 활보폭, 버그 균형척도에서 유의한 증가와 최대 동요속도, 동요거리, 오른쪽 기저 지지면, 오른쪽 양하지 지지기, 왼쪽 기저지지면, 왼쪽 양하지 지지기에서 유의한 감소는 균형 제어에 긍정적인 영향을 미칠 것으로 판단된다. 따라서 이러한 균형 제어 능력의 향상은 노인의 보행에 있어서의 낙상 예방에 효과적일 것으로 사료된다.

• Journal of the Korea Concrete Institute
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• v.23 no.2
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• pp.245-252
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• 2011

Currently, the design guidelines for the prevention of progressive collapse are not available in Korea due to the lack of study efforts in progressive collapse resistance evaluation of RC flat plate system. Therefore, in this study, three types of analysis were conducted to evaluate the progressive collapse resistance of a RC flat plate system. A linear static analysis was carried out by comparing the demand-capacity ratio (DCR) differences of the systems using the alternate load path method, which is the guideline of GSA. A dynamic behavior was investigated by checking the vertical deflection after removal of the column using the linear dynamic analysis. Lastly, a maximum load factor was investigated using the nonlinear static analysis. The finite element (FE) analyses were conducted using various parameters to analyze the results obtained using effective beam width (EB) model and plate element FEM (PF) model. This study results showed that the strength contributions of the slab in the EB models are underestimated compared to those obtained from the PF models. Therefore, a detailed FE analysis considering the slab element is required to thoroughly estimate the progressive collapse resisting capacity of flat plate system. The scenario of the corner column (CC) removal is the most dangerous conditions where as the scenario of the inner column (IC) removal is the least dangerous conditions based on the consideration of various parameters. The analysis results will allow more realistic evaluations of progressive collapse resistance of RC flat plate system.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.12 no.2
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• pp.170-177
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• 2019

In this paper, three theories for improving the stability of quadruped robot are presented. First, the Minimum-Jerk Trajectory is used to optimize the leg trajectory. Second, we compare the newly proposed sine wave and the conventional LSM in this paper based on the Jerk value. Third, we calculate the optimum stride of the sway through repetitive robot simulation using ADAMS-MATLAB cosimulation. Through the above process, the improvement of the robot walking is compared with the existing theory. First, the average gradient of the point where the leg trajectory changes rapidly was reduced from at least 1.2 to 2.9 by using the Minimum-Jerk targetory for the movement of the body and the end of the leg during the first walk, thereby increasing the walking stability. Second, the average Jerk was reduced by 0.019 on the Z-axis, 0.457 on the X-axis, and 0.02, 3D on the Y-axis by 0.479 using the Sin wave type sways presented in this paper, rather than the LSM(Longitude Stability Margin) method. Third, the length of the optimal stride for walking at least the Jerk value was derived from the above analysis, and the 20cm width length was the most stable.

• Venture DIGEST
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• s.101
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• pp.56-57
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• 2006

흔히 인생을 '마라톤'에 비유한다. 스피드보다는 페이스 조절에, 기록보다는 완주 자체에 더 많은 의미를 부여하는 마라톤. 도착점이 보이지 않는 42.195km는 때로는 견디기 힘든 고통을, 그리고 이를 넘어서는 희열을 안겨주기에 드라마가 된다. 벤처에도 '마라톤'이 있다. 바로 평균 12년이란 시간이 걸린다는 신약개발. 그리고 그 척박한 길을 당당한 보폭으로 뛰고 있는 뉴로제넥스와 물심양면으로 돕는 서울대 유전공학특화 창업보육센터. 지금, 이들의 성공 레이스가 막이 오른다.