• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1999년도 추계학술대회 논문집 - 한국공작기계학회
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• pp.131-136
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• 1999

This paper proposes the robot inverse calibration method using a neural networks. A highorder networks called Pi-Sigma networks has been used. The Pi-Sigma networks uses linear summing units in the hidden layer and product unit in output layer. The inverse calibration model which compensates the difference of joint variables only between measuring value and analytic value about the desired pose(position, orientation) of a robot is proposed. The compensated values are determined by using the weights obtained from the learning process of the neural networks previously. To prove the reasonableness, the SCARA type direct drive robot(4-DOF) and anthropomorphic robot(6-DOF) are simulated. It shows that the proposed calibration method can reduce the errors of the joint variables from $\pm$2$^{\circ}$to $\pm$ 0.1$^{\circ}$.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1999년도 춘계학술대회 논문집
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• pp.199-204
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• 1999

The robot inverse calibration method using a neural networks is proposed in this paper. A high-order networks has been used in this study. The Pi-Sigma networks uses linear summing units in the hidden layer and product unit in output layer. The inverse calibration model which compensates the difference of joint variables only between measuring value and analytic value about the desired pose(position orientation) of a robot is proposed. The compensated values are determined by using the weights obtained from the learning process of the neural networks previously. To prove the reasonableness, the selected compliance automatic robot arm type direct drive robot and anthropomorphic robot are simulated. It shows that the proposed calibration method can reduce the errors of the joint variables from ${\pm}$0.15$^{\circ}$to ${\pm}$0.12$^{\circ}$.

• 한국운동역학회지
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• 제31권3호
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• pp.183-188
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• 2021

Objective: The purpose of this study was to develop a stretchable joint motion sensor that is based on silver nano-particle. Through this sensor, it can be utilized as an equipment for rehabilitation and analyze joint movement. Method: In this study, precursor solution was created, after that, nozel printer (Musashi, Image master 350PC) was used to print on a circuit board. Sourcemeter (Keithley, Keithley-2450) was used in order to evaluate changes of electric resistance as the sensor stretches. In addition, the sensor was attached on center of a knee joint to 2 male adults, and performed knee flexion-extension in order to evaluate accurate analysis; 3 infrared cameras (100 Hz, Motion Master 100, Visol Inc., Korea) were also used to analyze three dimensional movement. Descriptive statistics were suggested for comparing each accuracy of measurement variables of joint motions with the sensor and 3D motions. Results: The change of electric resistance of the sensor indicated multiple of 30 times from initial value in 50% of elongation and the value of electric resistance were distinctively classified by following 10%, 20%, 30%, 40% of elongation respectively. Through using the sensor and 3D camera to analyze movement variable, it showed a resistance of 99% in a knee joint extension, whereas, it indicated about 80% in flexion phase. Conclusion: In this research, the stretchable joint motion sensor was created based on silver nanoparticle that has high conductivity. If the sensor stretches, the distance between nanoparticles recede which lead gradual disconnection of an electric circuit and to have increment of electric resistance. Through evaluating angle of knee joints with observation of sensor's electric resistance, it showed similar a result and propensity from 3D motion analysis. However, unstable electric resistance of the stretchable sensor was observed when it stretches to maximum length, or went through numerous joint movements. Therefore, the sensor need complement that requires stability when it comes to measuring motions in any condition.

• 비파괴검사학회지
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• 제20권4호
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• pp.290-295
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• 2000

최근 역타시공법 등에 의한 콘크리트 구조물의 시공이 증가 추세에 있다. 이 경우, 자주 발생되는 신 구타설 콘크리트 시공이음부의 공극은 향후 구조물의 구조적인 특성과 내구성 등에 큰 영향을 미치게 된다. 그러나 현재 제안되고 있는 비파괴 검사법으로는 효과적으로 이음부 공극을 평가하기에 많은 한계가 있다. 본 연구에서는 시공이음부의 콘크리트 충전상태를 평가하기 위해 철골철근 콘크리트와 무근 콘크리트 시험체내에 공극을 모의제작한 후, 초음파속도 측정을 실시하고, 화상처리기법을 이용하여 비교적 용이하게 해석 가능한 방법에 대해 검토하였다.

• 한국운동역학회지
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• 제32권4호
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• pp.134-140
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• 2022

Objective: This study aims to verify effect of 1-RM direct measurement method of back squat on beginners. Method: Total of 8 healthy adults were recruited for this study (age: 29 ± 3.81 yrs., height: 174 ± 3.83 cm., body mass: 74 ± 11.63 kg., 1RM: 96 ± 19.78 kg). All participants performed the back squat with 80%, 90% and 100% of the pre-measured 1RM. A three-dimensional motion analysis was performed with 8 infrared cameras and 3 channels of EMG were used for this study. One-way ANOVA with repeated measure was used for the statistical analysis with the significant level set to α=.05. Results: The ankle joint ROM in the transverse plane was significantly increased as the weight increased during the concentric contraction phase 2 (p < .05). In addition, the erector spinae and the gluteus maximus, which are synergist for the motion, showed a significant difference according to the increased weight (p < .05). Conclusion: Our results revealed that beginners increase potential dynamic knee valgus as weight increased. Therefore, it is thought that field coaches should pay attention to this to minimize and prevent injuries when measuring 1-RM for beginners.

• 한국자동차공학회논문집
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• 제5권1호
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• pp.38-48
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• 1997

A method for performing kinematic design sensitivity analysis of vehicle suspension systems is presented. For modeling of vehicle suspensions, the multibody dynamic formulation is adopted, where suspensions are assumed as combination of rigid bodies and ideal frictionless joints. In a relative joint coordinate setting, kinematic constraint equations are obtained by imposing cut-joints that transform closed-loop shape suspension systems into open-loop systems. By directly differentiating the constraint equations with respect to kinematic design variables, such as length of bodies, notion axis, etc., sensitivity equations are derived. By solving the sensitivity equations, sensitivity of static design factors that can be used for design improvement, can be obtained. The validity and usefulness of the method are demonstrated through an example where kinematic sensitivity analysis of a MacPherson strut suspension of performed.

• 근관절건강학회지
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• 제16권1호
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• pp.66-79
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• 2009

Purpose: The purpose of this study was to analyze the relationship between rehabilitation motive and social support perceived by spinal cord injury patients. Method: Data were collected by the questionnaires from 83 patients with spinal cord injury in a hospital. It was analyzed using descriptive statistics, t-test, ANOVA and Peason's correlation coefficients. Result: The social support score was 3.51 of 5 in average. The connectedness of subordinate portion was the highest as 3.57. The rehabilitation motive was 2.93 of maximum 4.00 in average. Among sub-dimensions of the rehabilitation motive, the mean score of change oriented motivation was 3.27 as the highest. The higher the direct support, the higher the indirect support(r=.663, p=.000). The higher the rehabilitation motive, the higher the direct(r=.282, p=.010) and indirect support(r=.397, p=.000). Conclusion: According to this study, the social support had the significant relationship with the rehabilitation motive. The social support was the key factor to enhance the rehabilitation motive psychologically. Finally, there is a need to develop the nursing intervention improve the social support for the spinal cord injury patients.

• 터널과지하공간
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• 제24권1호
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• pp.46-54
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• 2014

암반 구조물의 안정성에 결정적인 영향을 미치는 절리의 특성을 파악하기 위해서는 일반적으로 직접전단시험을 통한 연구가 수행되고 있으나, 본 연구에서는 3차원 개별요소법에 근거한 3DEC을 사용하여 직접전단시험을 수치해석적으로 수행하였다. 톱니각과 강도가 상이한 인공 절리시험편에 대해 수직하중을 4단계로 변화시켜가며 일정수직하중 조건에서 실험실 직접전단시험으로 최대전단강도를 측정하였다. 그리고 실내시험을 통해 얻은 시험편의 역학적 물성으로 수치해석 모델링을 수행하였고, 획득한 전단강도를 실험실 직접전단시험으로 수행한 전단강도와 비교 분석하였다. 그 결과 개별요소법에 의한 수치해석은 암반의 전단거동을 잘 모사할 수 있을 것으로 사료된다.

• The Journal of Korean Physical Therapy
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• 제19권1호
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• pp.23-31
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• 2007

Purpose: As a preliminary study, the purpose of this study was to examine the indirect estimation of the lumbar intervertebral disc size by two anthropometric methods, in order to compare these indirect methods with the direct analysis by radiological imaging. Methods: The wrist, elbow, knee, and ankle joint (both right and left) diameters were measured in 52 volunteers, and then intervertebral disc size was calculated using two anthropometric methods (Colombini and modified Colombini). The data were analysed with independent t-test to assess clinical usefulness. Results: When using right and left joint diameter, there was no significant difference in the estimation value of the L4-5 and L5-S1 intervetebral disc sizes. However, the study has shown that male subjects have significantly larger L4-5 and L5-S1 intervertebral disc sizes, compared with those of female subjects. In addition, disc sizes calculated by Colombini's formula were significantly larger than modified Colombini's formula. Conclusion: The indirect estimation of the intervertebral disc size by anthropometric method can be considered as a clinically useful method. However, further study should be conducted to compare anthropometric values with other radiological imaging.

• 한국시뮬레이션학회논문지
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• 제28권1호
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• pp.99-107
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• 2019

기존 본 연구팀에서 연구한 직사화기 무기효과 산출방법론은 JMEM(Joint Munitions Effectiveness Manuals : 합동탄약효과편람)내(內) 표적에 대해서만 무기효과자료를 산출 가능하다는 제한 사항을 가지고 있었다. 따라서 본 연구에서는 JMEM 이외의 현실적 표적을 추가하여 무기효과자료를 산출하는 방법을 인공신경망(ANN : Artificial Neural Network)을 적용하여 도출하는 데 중점을 두었다. 즉, 미국 JMEM내(內) 표적의 제원과 효과지수인 취약면적(Av : vulnerable area)을 이용하여 인공신경망의 예측모델을 학습시키고, 학습된 예측모델에 현실적 표적의 제원을 적용하여 취약면적을 계산한다. 최종적으로 본 연구팀이 연구한 기존 직사화기 무기효과 산출방법론에 계산된 취약면적을 적용하여 살상확률(Pk)을 계산하는 방법론을 제시하였다.