• 한국지반공학회지:지반
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• 제14권2호
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• pp.55-66
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• 1998

본 논문의 목적은 불연속면의 공학적 특성, 사면형상과 하중조건 등을 고려한 암반사면 전도 파괴에 대한 안정해석방법을 개발하고 적용하는테 있다. 암반사면의 전도파괴에 대한 안정은 경사각 $\alpha_s$ 와 H/t비에 주된 영향을 받는다. 설계적용을 위하여 매개변수에 따른 My띠와 $\alpha$서 함수로 표현되는 암반사면 전도파괴에 대한 안정도표를 작성하였다. 안정도표에서 $\alpha_s$와 Hy띠가 작아질수록 안정성이 증가하는 경향을 보인다. 안정도표에서 안정영역은 간극수압변화에 따라 가장 크게 감소한다. 파괴영역의 변화는 지진력과 단계각에 가장 민감하다.

• Journal of Biosystems Engineering
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• 제16권4호
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• pp.346-354
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• 1991

Turning behavior of tractor-trailer system was studied to guide the tractor and trailer. Based upon kinematic relationship between the tractor and the trailer, a mathematical model was developed and analyzed by computer simulation. A field test was carried out to verify the mathematical model. Following conclusions were drawn from this study. 1. A mathematical model and a simulation program for turning behavior of tractor-trailer system were developed. 2. The results of the field tests showed that the RMS errors were less than 0.33m and the mathematical model based upon kinematic relationship can be used for mapping guidance system for tractor and trailer. 3. As the steering angle was increased, the turning radius was decreased. When the tractor travelled at the low speed, the travel speed of the tractor did not affect turning radius but did affect running time and stability for steering. 4. When the tractor travelled under the critical velocity, the towed trailer followed smoothly. When the the tractor travelled faster than the critical velocity, the towed trailer oscillated. The critical velocity was determined from the specification of the tractor and the trailer.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1999년도 춘계학술대회논문집
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• pp.225-228
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• 1999

In a plastically deformed body the formation of a shear band is widely observed in the engineering materials during rapidly forming process for a thermally rate-sensitive material. The localized shear bond stems from evolution of a narrow region in which intensive plastic flow occurs. The shear band often plays as a precursor of the ductile fracture during a forming process. The objectives of this study are to investigate the localization behaivor by using numerical method thus predict the failure. In this work the implicit finite difference scheme is preformed due to the ease of covergence and the numerical stability. This study is based on an analysised material with hardening as well as thermally softening behavior which includes isotropy strain hardening. Furthermore this paper suggests that an anticipated and suggested a kinematic hardening constitutive equation be requried to predicte a more accurate strain level wherein a shear band occurs.

• Smart Structures and Systems
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• 제7권3호
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• pp.169-184
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• 2011

We review the current understanding of modularity in biological motor control and its forms, and then relate this modularity to proposed modular control structures for biomimetic robots. We note the features that are different between the robotic and the biological 'designs' with features which have evolved by natural selection, and note those aspects of biology which may be counter-intuitive or unique to the biological controls as we currently understand them. Biological modularity can be divided into kinematic modularity comprised of strokes and cycles: primitives approximating a range of optimization criteria, and execution modularity comprised of kinetic motor primitives: muscle synergies recruited by premotor drives which are most often pulsatile, and which have the biomechanical effect of instantiating a visco-elastic force-field in the limb. The relations of these identified biological elements to kinematic and force-level motor primitives employed in robot control formulations are discussed.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2006년도 International Symposium on GPS/GNSS Vol.1
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• pp.191-196
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• 2006

In GPS Positioning, the error of satellite orbit will affect user's position accuracy directly, it is important to determine the satellite orbit precise. The real-time orbit is needed in kinematic GPS positioning, the precise GPS orbit from IGS would be delayed long time, so orbit prediction is key to real-time kinematic positioning. We analyze the GPS predicted ephemeris, on the base of comparison of EKF and UKF, a new orbit prediction method is put forward based on UKF in this paper, the result shows that UKF improves the orbit predicted precision and stability. It offers a new method for others satellites orbit determination as Galileo, and so on.

• Geomechanics and Engineering
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• 제2권2호
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• pp.125-140
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• 2010

Slope stability analysis of the right abutment of a railway bridge proposed at about 350 m above the ground level, crossing a river and connecting two huge hillocks in the Himalayas, India is presented in this paper. The site is located in a highly active seismic zone. The rock slopes are intensely jointed and the joint spacing and orientation are varying at different locations. Static slope stability of the rock slope is studied using equivalent continuum approach through the most commonly used commercial numerical tools like FLAC and SLOPE/W of GEOSTUDIO. The factor of safety for the slope under static conditions was 1.88 and it was reduced by 46% with the application of earthquake loads in pseudo-static analysis. The results obtained from the slope stability analyses confirmed the global stability of the slope. However, it is very likely that there could be possibility of wedge failures at some of the pier locations. This paper also presents the results from kinematics of right abutment slope for the wedge failure analysis based on stereographic projections. Based on the kinematics, it is recommended to flatten the slope from 50o to 43o to avoid wedge failures at all pier locations.

• 대한물리의학회지
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• 제17권3호
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• pp.23-30
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• 2022

PURPOSE: This study was designed to investigate the effects of keeping contraction of abdominal and pelvic floor muscles on 3D pelvic stability in individuals with nonspecific chronic low back pain (CLBP) during normal speed walking. METHODS: The subjects were 20 adults with CLBP deformity and had moderate pain intensity of the visual analog scale. A three-dimensional camera capture system was used to collect kinematic pelvic motion data with and without contraction of the abdominal and pelvic floor muscles during gait. The subjects were asked to walk on a walkway in the lab room and they were attached 40 reflective markers to their pelvic segment and lower extremities. A Visual3D Professional V6 program and Vicon Nexus software were used to analyze 3D pelvic kinematic data. RESULTS: There were significant differences between with and without contraction of the abdominal and pelvic floor muscles of the pelvic depression and the total pelvic motion in coronal plane during gait (p < .05). However, there were no significant differences in any of the maximal motion of the pelvic segment in sagittal and transverse motion plane according to the different muscle contraction conditions (p > .05). CONCLUSION: The results of this study suggest that maintaining co-contraction of the abdominal and pelvic floor muscles in individuals with CLBP increased pelvic stability and contributed to preventing excessive pelvic movements during gait.

• 한국해안·해양공학회논문집
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• 제35권2호
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• pp.41-48
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• 2023

본 연구에서는 바닥의 움직임에 따른 파랑의 생성 및 변화를 모의할 수 있는 간단한 선형 수치해석 기법을 소개한다. 연속방정식과 선형의 동역학적 및 운동학적 자유수면 경계조건, 선형의 운동학적 바닥 경계조건을 공간에 대해 푸리에 변환한 후 파수 영역에서 수치해석을 수행하며, 결과는 푸리에 역변환을 통해 공간영역에서 표현된다. 파수 영역에서 동역학적 자유수면 경계조건과 운동학적 자유수면 경계조건이 수치적으로 계산되며, 이 때 평균수면 (z = 0)에서의 속도포텐셜은 연속방정식과 운동학적 바닥 경계조건을 만족한다. 삼각형 및 사각형 형상의 바닥이 주기적으로 움직이는 경우의 파랑 생성 및 전파에 대해 검토하였다. 간편 수치해석 기법을 이용한 결과는 기존의 선형 해석해와 비교하였으며, 거의 일치하는 결과를 보였다. 계산 시간간격(Δt)과 계산 파수간격(Δk)에 따른 수치해석 결과의 안정성에 대해서도 검토하였다. 검토 결과 Δt ≤T(주기)/1000, Δk ≤ π/100 일 때 수치해석에 의한 결과가 적절하게 도출되는 것으로 나타났다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.2759-2764
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• 2003

Humans usually employ more joints than they actually need, and thus they can be categorized as a kinematically redundant system. Therefore, the behavior of the human body can be analyzed by several redundancy resolution algorithms. Different from typical industrial robots that are fixed to the ground, the COG/ZMP condition should be taken into account in the human body motion in order not to fall down. Thus a COG/ZMP stability index is employed as a measure of stability. Kinematic redundancy inherent in the human body can be exploited to satisfy the COG/ZMP condition. Simulation result shows that the COG/ZMP condition can be satisfied by exploiting the null space motion of the kinematically redundant human body model.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 1993년도 Proceedings of International Conference for Agricultural Machinery and Process Engineering
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• pp.1147-1156
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• 1993

In order to analyze lateral control in the backward maneuver of a tractor -trailer combination , a kinematic vehicle model and a human operator model with time delay were utilized for the operator/vehicle system. The analysis was carried out using the frequency domain approach. The open-loop stability of the vehicle motion was analyzed through the transfer functions. The sensitivity of the stability of the vehicle motion. to a change in the steering angle, was also analyzed. A mathematical model of the closed -loop operator/vehicle system was then formulated. The closed -loop stability of the operator /vehicle system was then analyzed. The effect of the delay time on the system was also analyzed through computer simulation.