• 한국정밀공학회지
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• 제33권3호
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• pp.173-181
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• 2016

This paper reports on the development of a roller-cam clutch mechanism. This mechanism can transfer bidirectional torque with high backdrivability, as well as increase actuation energy efficiency, in electrical exoskeleton robots. The developed mechanism was installed at the robot knee joint and unclutched during the swing phase which uses less metabolic energy, thereby functioning as a passive joint. The roller-cam clutch aimed to increase actuation energy efficiency while also producing high backdrivability by generating zero impedance for users during the swing phase. To develop the mechanism, mathematical modeling of the roller-cam clutch was conducted, with the design having more than three safety factors following optimization. Titanium (Ti-6AL-4V) material was used. Finally, modeling verification was done using ANSYS software.

• 근관절건강학회지
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• 제7권1호
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• pp.40-52
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• 2000

Recently with the development in computer technology and its communication system, many changes in medical informatics enable us to use various medical information regardless of time or place. There are many home pages on the web, which provide medical counseling and hospital information. On May 11th 1999, Korean Rheumatology Health Professions Society began its new service as a home page on the web with various rheumatologic health information, questioning/ answering, and so on. This study was undertaken to examine the content and the purpose of health counseling on the web. The data was collected from 173 questioners who visited questioning/ answering site in the KRHPS home page for May 11th, 1999 through November 10th, 1999. Most of the questioners consulted the health problems of their or their families. Over two thirds of them were already diagnosed medically. Rheumatoid arthritis was the most frequent one. Other diseases, such as, osteoarthritis, ankylosing spondylitis, Still's disease were also on the list. Most of the questioners wanted to know treatment strategies, to consult about their symptoms, and to make diagnosis. And many questioners wanted detailed explanations about their diseases or the informations regarding the hospital. These findings suggest that the health counseling on the web may be used to supplement the lack of direct medical interviews with doctors. It also is expected to guide the patients to the right direction.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.643-644
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• 2006

The purpose of this study is to experimentally analyze swing motion with soft golf clubs and compare with that with normal golf clubs. Soft golf is newly devised recreational sport based on golf but focus on the playability for the elderly. The subject fur the experiment performed swing motion using a normal golf club and a soft golf club in turn. The swing motion of the subjects was tracked using an opto-electric three-dimensional motion analysis system. The results were compared against those obtained with a normal golf club. The range of motion was analyzed along with top head speed for two cases. It was found that higher club head speed could be achieved with reduced range of motion at lumbar joint using soft golf club when compared against the swing using regular club. The lower range of motion fur lumbar bending means reduced risk of injury at the joint. So, it is projected that we can reduce the risk of injury with soft golf while maintaining the club head speed.

• 한국재료학회지
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• 제26권7호
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• pp.376-381
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• 2016

For the development of a low-melting point filler metal for brazing aluminum alloy, we analyzed change of melting point and wettability with addition of Sn into Al-20Cu-10Si filler metal. DSC results showed that the addition of 5 wt% Sn into the Al-20Cu-10Si filler metal caused its liquidus temperature to decrease by about 30 oC. In the wettability test, spread area of melted Al-Cu-Si-Sn alloy is increased through the addition of Sn from 1 to 5 wt%. For the measuring of the mechanical properties of the joint region, Al 3003 plate is brazed by Al-20Cu-10Si-5Sn filler metal and the mechanical property is measured by tensile test. The results showed that the tensile strength of the joint region is higher than the tensile strength of Al 3003. Thus, failure occurred in the Al 3003 plate.

• 한국자동차공학회논문집
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• 제15권1호
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• pp.56-63
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• 2007

In case of bus rollover, the body structure of the bus should be designed to ensure the survival space for passengers. So, this study focuses on evaluating rollover strength through a computer simulation using the commercial code, LS-DYNA3D at the initial stage of vehicle development. For this study, section structure was modeled using a simple beam element, and impact boundary conditions required by ECE(Economic Commission for Europe) regulation No.66 were applied. In order to confirm the validity of the beam element bus model, the results compared with the test results and shell element bus model. The analysis errors from beam element bus model are due to the difference in strain energy of joint area between beam and shell model. In this study, a method for the joint modeling was suggested by using nonlinear springs to which the collapse mechanisms were applied.

• 한국생산제조학회지
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• 제26권1호
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• pp.89-99
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• 2017

This paper describes the development of a thigh wearable robot for power assistance during stair climbing. In the wearable robot developed in this study, high-power BLDC motors and high-capacity harmonic reduction gears are used to effectively assist the thigh muscle during stair climbing. In particular, normal ground and stair are distinguished accurately by using wireless smart shoes, and the stair climbing assistance is performed by activating the actuators at an appropriate time. Impedance of the hip joint was effectively reduced by performing friction compensation of the gears, and a wearing adjustment mechanism was designed to fit the robot to the thigh by conveniently modifying the width and tilting angle of the robot using set collars. Consequently, the performance of the developed thigh wearable robot was verified through stair climbing experiments with EMG measurement.

• 대한기계학회논문집A
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• 제41권8호
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• pp.771-782
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• 2017

본 논문은 노약자들의 발목근력보조를 위한 착용형 로봇에 대해서 서술하였다. 기존 착용형 로봇들은 보행 시 필요한 근력을 보조하기 위해 대부분 모터와 감속기를 사용하였다. 하지만 모터와 감속기의 조합은 무게가 무거울 뿐만 아니라 감속기 치차의 마찰때문에 실제 사람의 근육과 달리 강성과 토크를 동시에 제어하기 어려운 한계가 있다. 따라서 본 연구에서는 모터/감속기 조합보다 가볍고 안전하며 근력을 보조하는 힘을 충분히 발휘할 수 있는 Mckibben 공압 근육을 사용하였다. 발목의 피칭 모션에 이용되는 종아리 가자미근 및 앞정강근의 힘을 한 쌍의 공압 근육을 사용한 상극구동으로 보조하였으며, 상극구동제어를 위해 상극구동 모델 파라미터들을 실험적으로 도출하였다. 사용자의 보행의지를 판단하고자 발바닥에 부착된 압력변위센서로 압력과 압력중심위치를 측정하여 발바닥의 하중과 발목토크를 계산하였고, 이를 기반으로 공압 근육 관절의 강성과 토크를 동시에 제어하였다. 최종적으로, 트레드밀에서 근전도 신호를 측정하여 발목근력보조로봇의 성능을 실험적으로 입증하였다.

• 한국콘텐츠학회논문지
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• 제21권4호
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• pp.137-152
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• 2021

대외적인 활동이 거의 없던 북한에서 최근 해외 논문발표가 급증하고 있다. 본 연구에서는 북한의 해외발표논문을 계량분석하여 북한의 연구개발 동향변화를 파악하고, 향후 국내 연구자들과의 공동연구로 발전시킬 수 있는 가능성을 모색하고자 한다. 이를 위해 1986년 이후 북한 연구자가 포함된 해외발표논문을 대상으로 빈도분석과 네트워크 분석을 실시하였다. 분석은 저자, 연구기관, 국가, 연구분야 등을 대상으로 하였으며, 김정은 집권 전과 후로 구분하여 변화를 분석하였다. 분석결과에 따르면 김정은 집권 후 8년간 해외논문 발표가 급격히 증가하면서, 논문발표 상위 연구자나 연구기관, 공동연구 영향력 상위 연구자 등의 구성도 많은 변화가 나타났다. 김정은 집권 후 북한 연구자나 연구기관의 비중이 상대적으로 증가하였으며, 공동연구 영향력 상위 연구자들간 네트워크 컴포넌트가 형성되어 있어서 특정 연구주제에 집중하는 모습이 관찰되었다. 북한 연구자들의 주요한 해외 협동연구자나 연구기관은 중국의 비중이 높게 나타났다.

• International Journal of Concrete Structures and Materials
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• 제10권4호
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• pp.479-497
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• 2016

Many experimental studies have evaluated the in-plane behavior of reinforced concrete frames in order to understand mechanisms that resist progressive collapse. The effects of transverse beams, frames and slabs often are neglected due to their probable complexities. In the present study, an experimental and numerical assessment is performed to investigate the effects of transverse beams on the collapse behavior of reinforced concrete frames. Tests were undertaken on a 3/10-scale reinforced concrete sub-assemblage, consisting of a double-span beam and two end columns within the frame plane connected to a transverse frame at the middle joint. The specimen was placed under a monotonic vertical load to simulate the progressive collapse of the frame. Alternative load paths, mechanism of formation and development of cracks and major resistance mechanisms were compared with a two-dimensional scaled specimen without a transverse beam. The results demonstrate a general enhancement in resistance mechanisms with a considerable emphasis on the flexural capacity of the transverse beam. Additionally, the role of the transverse beam in restraining the rotation of the middle joint was evident, which in turn leads to more ductile behavior. A macro-model was also developed to further investigate progressive collapse in three dimensions. Along with the validated numerical model, a parametric study was undertaken to investigate the effects of the removed column location and beam section details on the progressive collapse behavior.

• 기술혁신학회지
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• 제11권4호
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• pp.532-562
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• 2008

최근 국가연구개발사업의 성과관리 측면에서 논의되고 있는 이슈 가운데 하나가 공동연구개발을 통해 발생된 지적재산권의 관리에 관한 것으로, 현행 법제에 따르면 국가공동연구개발 특허는 주관연구기관과 참여기업이 투자지분에 따라 공동으로 소유하도록 하고 있는 바, 과연 이것이 법리상으로나 실제상 바람직한가에 대하여 많은 논의들이 일어나고 있다. 국가공동연구개발 특허는 공공자산 및 공유특허로서의 속성상 여러 관련법령에 의하여 복합적으로 규율되는 구조를 띠고 있으며, 그 권리의 행사에 있어서도 일정한 제약이 따르는 등 일반특허와는 다른 특성을 갖는다. 이 글은 국가공동연구개발 과정에서 발생된 특허의 귀속 및 활용에 관한 규율법리를 체계적으로 검토하고, 이를 바탕으로 현행 제도의 발전적 개선방안을 모색함을 목적으로 하고 있다. 이에 따라 본 연구에서는 국가공동연구개발 특허의 의의와 법적 규율체계를 살펴보고, 공동발명 특허권의 귀속 및 활용에 관한 법적 지배원리를 규명한 다음, 현행 제도의 문제점과 개선방안에 대하여 살펴보았다.