• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.121-124
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• 1999

본 논문에서는 선형배열을 이용하여 음향을 측정하기 위한 새로운 빔형성 알고리듬을 제안한다. 제안 알고리듬은, FIR필터 설계기법에 의해 가중상수 및 원하는 빔패턴을 설정하고 이를 초기치로 사용하여 원하는 빔패턴과의 오차가 최소가 되도록 가중상수를 최적화시킨다. 주파수영역의 지향지수 균일성 유지를 위해 옥타브대역을 부대역으로 세분하고 의사역행렬에 의해 전달행렬을 정방행렬화하여 부대역별로 최적화를 수행한다.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.10
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• pp.233-239
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• 2003

Three dimensional joint motion data were obtained using X-ray and precise magnetic sensors. Six metal markers were inserted on the femur and the tibia to set the coordinate system. Two magnetic position sensors were used to record motion data and these positions were transformed into the knee motion. The quadriceps muscle was extended in an automatic manner by an extraction machine. Results of the knee joint motion were the same as the clinical data. The proposed method is found to be reasonable in describing the knee motion so that these motion data can be used to simulate the normal knee joint.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.3 s.246
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• pp.241-248
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• 2006

Shoe cushioning systems are important to prevent body injuries. This study developed and evaluated a cushioning system to reduce impact force on the heel. The cushioning system suggested consist of a polyurethane pocket, which contains water and porous grains of open cell to dissipate the energy effectively. Load-displacement curves fer the shoe cushioning system were obtained from an instrumented testing machine and the results were compared with various pockets with air, water or grains. Mechanical testings showed that the pocket with 5g porous grain was the best for the cushioning system. This system can be applied to the design of various kind of sport shoes.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.31 no.8
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• pp.889-895
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• 2007

Quantifying dynamic stability is important to assessment of falling risk or functional recovery for leg injured people. Human locomotion is complex and known to exhibit nonlinear dynamical behaviors. The purpose of this study is to quantify major joints of the body using chaos analysis during walking. Time series of the chaotic signals show how gait patterns change over time. The gait experiments were carried out for ten young males walking on a motorized treadmill. Joint motions were captured using eight video cameras, and then three dimensional kinematics of the neck and the upper and lower extremities were computed by KWON 3D motion analysis software. The correlation dimension and the largest Lyapunov exponent were calculated from the time series to quantify stabilities of the joints. This study presents a data set of nonlinear dynamic characteristics for eleven joints engaged in normal level walking.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.412-412
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• 2000

This paper presents a task teaching method for off-line programming of a multi-robot system. Teaching commands were developed in order to simplify a complex teaching process, to shorten the setup time for new working environment and to have flexibility for changes in working environment. Four teaching commands can be used to automatically generate trajectories of an end-effector of the robot in electronics assembly line. The robots used in the work cell are a four-axis SCARA robot and six-axis articulated robot. Each robot is controlled in a independent way while objects, working environment and robots are modeled in corresponding modules, respectively. The off- line programming system developed uses OpenGL for a smooth graphic effect in Window s where three dimensional CAD data can be leaded for graphical modeling.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.312-312
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• 2000

Human sensibility ergonomics is applied to evaluation of dynamic performance of a vehicle driving simulator. Vehicle, driving environment, and human perception models are constructed and integrated. Driving simulations are carried out based on these models. This study defines a set verbal expressions collected and investigates which are the most appropriate for describing the fidelity of translational and angular accelerations of the driving simulator. An statistical analysis is uscd to find correlation between the ergonomic sensibility and the cut-off frequency of the washout algorithm. This study suggests a methodology to obtain an ergonomic database which can be used for the performance evaluation of dynamic environments.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.314-314
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• 2000

This study deals with the analysis of the effectiveness of a safer belt in frontal crash. ATB, Articulated Total Body, program is used as a dynamics solver of the occupant model. ATB is a public code, however, the program is somewhat cumbersome to use due to lack of sufficient user interface. A preprocessor and a postprocessor are, therefore, developed for a user friendly graphic interface in Windows environment. Dialog boxes are used for an interface with GEBOD, Generator of Body Data, for human anthropometry and with ADAMS for vehicle dynamics. It is found through three test simulations that simulated results are in good agreement with those obtained by ATB. The effect of the initial slack of safety belt is investigated for frontal crash using the developed program.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2000.11a
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• pp.207-211
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• 2000

주행 시뮬레이터는 여러 가지 주행상황을 탑승자에게 전달하고자 하는 장치이다. 기존의 주행 시뮬레이터에 관한 대부분의 연구는 탑승자의 감성평가에 관해 이루어지지 않았다. 본 논문에서는 탑승자의 감성을 주행 시뮬레이터에 피드백하여 주행 시뮬레이터의 성능을 향상시키고자 한다. 이를 위하여 본 논문에서는 다변량 해석형 수법, 기능 전개형 수법, 가상현실 감성공학 등을 응용하여 동적 시스템에 대한 측정 및 평가방안을 연구하였다. 설정된 목표감성인 운동감에 대한 20여개의 감성어휘 추출과 주행 시뮬레이터에 대한 분석을 통하여 차단주파수를 감성요인으로 정하였다. 감성어휘와 감성요인간의 관계를 평가하기 위하여 감성실험을 수행하였고, 그 측정결과를 통계학적으로 분석하였다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.521-522
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• 2006

Occlusal loading is considered as the main factor of noncarious cervical lesions. The goal of this study is to identify stress distribution using three dimensional finite element analysis, when occlusal loading is applied on the cervical lesion of human tooth. A finite element model was constructed from micro-CT image and three kinds of static force(500 N) were assumed. In all cases stress concentrates on the same area in the cement-enamel junction. This finding is consistent with published experimental results.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.523-524
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• 2006

It is necessary to have a model that describes the anthropometry of the crash victim with a sufficient accuracy Koreans, however, do not have their own pedestrian dummies to be used in pedestrian collision tests. They have to use European and American dummies for their safety analysis. In this study scaled pedestrian dummies were constructed by using MADYMO. The dummies represent Korean average males and females aged from 25 to 29. The scaled Korean dummies and MADYMO human models were used to obtain and compare the pedestrian dynamic behaviors and injury criteria during the impact events.