• International Journal of Precision Engineering and Manufacturing
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• 제7권3호
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• pp.66-71
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• 2006

Some wheelchair users with neuromuscular disorders experience involuntary extensor thrusts, which may cause injuries via impact with the wheelchair, cause the user to slide out of the wheelchair seat, and damage the wheelchair. Knowledge of the human-generated forces during an extensor thrust is of great importance in devising safer, more comfortable wheelchairs. This paper presents an efficient method for identifying human-generated forces during an extensor thrust. We used an inverse dynamic approach with a three-link human body model and a system for measuring human body motion. We developed an experimental system that determines the angular motion of each human body segment and the force at the footrest, which was used to overcome the mathematical indeterminacy of the problem. The proposed method was validated experimentally, illustrating the force-identification process during an extensor thrust.

• 한국시뮬레이션학회논문지
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• 제20권1호
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• pp.69-77
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• 2011

최근 군은 과거 냉전시대와 다른 상황에 능동적으로 대처하고 비용 대비 훈련의 효과를 극대화하기 위한 방안으로 모델링 시뮬레이션 기법에 많은 관심을 보이고 있다. 이 모델링 시뮬레이션을 이용한 훈련이 효과적이기 위해서는 좀 더 사실적인 전장 환경과 전투상황을 모의해야 하는데, 최근에 이를 위해서 컴퓨터상에서 인간 행위와 부대의 집단논리를 표현하는 CGF(Computer Generated Forces)에 대한 기술 개발이 주목받고 있다. 인간 행위를 모델링하는 CGF는 자동화된 병력을 모의함으로써 적군을 모의하거나 미래 전투실험, 새로운 전투개념 개발 등 중요하면서도 다양한 역할을 수행 할 수 있다. 이번 연구에서는 CGF 가상군인의 자율지능화의 방안을 고찰해보고자 한다. 군사시뮬레이션상의 가상군인의 자율지능화의 첫걸음인 과업행위 목록의 적용을 과업행위의 기본요소인 METT+T를 기반으로 그 적용과정을 설명한다. 또한 군사모의 논리는 참 진의 이진값 표현이 외에도 '보유 무기가 충분하면 급속 공격을 빠르게 하라'와 같은 모의 규칙상에서는 군사 전문가에 의해서 결정될 수밖에 없는 '충분하다', '빠르다'와 같은 퍼지 팩트가 존재한다. 이러한 주관성이 가미된 많은 군사모의 논리를 완벽히 표현하기 위해서는 퍼지 추론을 이용하는 것이 효과적인데, 이를 이번 소부대 전투 시뮬레이션에 적용하여 보다 사실적인 모의가 가능하도록 하였다.

• 한국자동차공학회논문집
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• 제13권1호
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• pp.132-139
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• 2005

The driving position of head restraints and the relative risk of neck injury were studied in the computer simulation. MADYMO human model with the detail neck model was used to define the magnitude and direction of internal forces acting on the cervical spine during rear-end impact and to determine the effect of the initial position of the occupant's head with respect to the head restraints. Maximum reaction forces were generated during the head contact to the restraint and relatively large forces were generated at each spinal components in lower cervical spine in proportion to backset and height distance increasement.

• 한국CDE학회논문집
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• 제17권1호
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• pp.62-70
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• 2012

This paper proposes a novel discomfort assessment method for truck ingress and egress motions based on the maximum-voluntary-contraction (MVC) ratios of muscles obtained by biomechanical analysis of human musculoskeletal models. In this study, a human motion to enter and exit a truck cabin with different types and heights of footsteps is first measured using an optical motion capture system and load sensors. Next, in a biomechanical analysis system, a human musculoskeletal model with contacting conditions on footsteps and handles is modeled, and then joint torques and muscles forces are calculated by inverse dynamics of the musculoskeletal model with the motion data. Finally, the MVC ratios for the muscles are calculated and their statistical values are used as the measure of discomfort. To ensure the feasibility of our method, subjective discomfort levels have been investigated through the participants' experiments and questionnaires and compared to the results of our method. Comparing to the existing methods based on joint angles or torques, our approach provide a more essential criterion for discomfort because it is based on the muscle contraction by which an active human motion is basically generated.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.1593-1597
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• 2003

The home service robot supports human beings by performing various kinds of works at home. This paper presents a simple control method for opening a door from the viewpoint of the mobile manipulation. The simulation shows various results of path planning and motion planning for opening a door. The joint trajectories were generated by the simulation system. In general, a six-axis force/torque sensor at an end-effector is needed in order to maintain the static equilibrium of the manipulator. But we show another method. From three components of applied forces which was directly obtained by the three-axis force sensor and three components of applied forces which was indirectly estimated by the joint-torque sensors, all of joint torques that will exactly balance forces at the end-effector in the static situation can be found. It is more practical method than using a six-axis force sensor in a wrist. Experimental results have shown that the opening a door can be realized more effectively from the suggested control method of mobile manipulation.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집A
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• pp.261-267
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• 2000

A mathematical model was developed to calculate the muscle force of lower extremity during the gait. We constructed a model of human locomotion, which includes a muscle-skeletal system with 7 segments and 16 lower limb muscles. Using a optimization technique, muscle forces variation of the lower extremity during the gait were generated and its result was verified by comparing a experimental results of EMG analysis. Moreover. the walking movement of the model could be compared quantitatively with those of experimental studies in human by inverse dynamics.

• 한국미생물·생명공학회지
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• 제48권4호
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• pp.423-428
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• 2020

In vitro evolution is a powerful technique for the engineering of yeast strains to study cellular mechanisms associated with evolutionary adaptation; strains with desirable traits for industrial processes can also be generated. There are two distinct approaches to generate evolved strains in vitro: the sequential transfer of cells in the stationary phase into fresh medium or the continuous growth of cells in a chemostat bioreactor via the constant supply of fresh medium. In culture, evolutionary forces drive diverse adaptive mechanisms within the cell to overcome environmental or intracellular stressors. Especially, this engineering strategy has expanded to the field of human cell lines; the understanding of such adaptive mechanisms provides promising targets for the treatment of human genetic diseases and cancer. Therefore, this technology has the potential to generate numerous industrial, medical, and academic applications.

• 한국정밀공학회지
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• 제25권8호
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• pp.37-44
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• 2008

Nowadays, the increasing global competition forces manufacturer to reduce the cost and time for implementation of manufacturing system. The AR(augmented reality) technology as a new human-machine interface introduces a noteworthy perspective for a new manufacturing system design. Using AR technology, a physically existing production environment can be superimposed with virtual planning objects. Therefore, the planning tasks can be validated without modeling the surrounding environment of the production domain during short process planning time. In this paper, we introduce the construction of AR browser and determine the optimal environment parameters for field application of AR system through lots of tests. And, many methods such as multi-marker coordinate system, division of virtual objects and so on, are proposed in order to solve the problems suggested from initial field test. Based on these tests and results, the test-bed of C/Pad assembly system is configured and robot program for C/Pad assembly is generated based on AR system.

• 한국운동역학회지
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• 제12권2호
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• pp.393-405
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• 2002

When our body is immersed in water, we experience weightlessness. The degree of weightlessness that we experience varies depending on the proportion of the body immersed in water, being governed by the relationship between the weight of body and the buoyant force acting on the body. Human body during the performance of swimming in no exception to these influences. Swimmers body is subject to a time and position dependent force system. Even the magnitude of the buoyant force acting on the swimmers body at every given instant and the corresponding position of the CB change continuously. The findings of this study support the following conclusions. The buoyancy torque was the primary source of bodyroll exhibited by front crawl swimmers performing at distance pace, accounting for 88 % of the bodyroll. Faster swimmers used buoyancy more effectively to generate bodyroll, partially supporting the postulation that an effective use of buoyancy for bodyroll may reduce the generated hydrodynamic forces to be wasted in non-propulsive directions and maximize forward propulsion.

• 로봇학회논문지
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• 제18권4호
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• pp.481-486
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• 2023

The purpose of this study is to optimize parameters of a contact model to obtain similar ground contact force of human walking. Dynamic walking simulation considering ground contact is performed to determine load specifications when developing walking assist robots. Large contact forces that are not observed in actual experimental data occur during the simulation at the initial contact (e.g., heel contact). The large contact force generates unrealistic large joint torques. A lower exoskeleton robot with no ankles is developed with the Matlab simscape and the nonlinear hyper volumetric contact model is applied. Parameters of the nonlinear hyper volumetric model were optimized using actual walking contact force data. As a result of optimization, it was possible to obtain a contact force pattern similar to actual walking by removing the large contact force generated during initial contact.