• Journal of the Korean Orthopaedic Association
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• v.55 no.1
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• pp.85-89
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• 2020

Bow hunter's syndrome is a rare disease that shows the symptoms of vertebrobasilar insufficiency resulting from a dynamic obstruction or stenosis of the vertebral arteries during neck movement. This paper reports a case of a 59-year-old male who visited the emergency room with diplopia, tinnitus, and gait disturbance. Magnetic resonance imaging and angiography revealed a multiple cerebellar infarct, total obstruction of the right vertebral artery, and dynamic obstruction of the left vertebral artery during neck extension. As the infarction worsened, a thrombectomy was done. Posterior decompression and fusion at C5-6 were performed for the left vertebral artery. The left vertebral arterial patency was confirmed by intraoperative and postoperative angiography. No recurrence of the symptoms was observed for six months after surgery. Physicians need to pay attention to the diagnosis of vertebrobasilar insufficiency caused by an obstruction of the vertebral arteries during neck extension in cervical instability patients.

• Proceedings of the IEEK Conference
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• 2003.07c
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• pp.2721-2724
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• 2003

This paper deals with a manipulability analysis of multi-legged walking robots in acceleration domain, that is the dynamic manipulability analysis of walking robot. Noting that the kinematic structure of the walking robot is basically the same with that of the multiple serial robot system holding one object, the analysis method for cooperating robot is converted to that of walking robot. With the proposed method, the bound of achievable acceleration of the moving body is easily derived from the given bounds on the capabilities of Joint torques. Several walking robot examples are analyzed with proposed method under the assumption of hard contact, and presented in the paper to validate the method.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.22 no.4
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• pp.768-778
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• 1998

Human beings usually absorb a shock from terrain during walking through the damping effects of joints, muscles and skin. With this analogy, a robot-leg with a shock absorber is built to absorb the impact forces at its foot during high-speed walking on irregular terrain. To control the hip position while walking, the dynamic controller suitable for high speed walking is designed and implemented based on a dynamic model by Kane's equation. The hip position tracking performances of various controllers (PID controller, computed torque controller and feedforward torque controller) are compared through the experiments of the real robot-leg.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.04a
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• pp.458-461
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• 2008

The primary objective of this study is to provide simple analytical tools to estimate dynamic characteristics of steel framed floor system in hospital building for vibration serviceability due to human activities, bogie, medical equipment. and so on. In order to evaluate the dynamic characteristics and vibration levels according to steel framed floor system, we had executed impact test and measurement on steel structure floor system in various hospital buildings. But perhaps most importantly, how to make the most of deduced design factor for design of hospital building. therefore we presented the access method such as the three-dimensional F.E. numerical analysis on the basis of the design drawing, and the properties of all floors for estimation of vibration level in hospital building.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10a
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• pp.959-964
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• 1992

This study treats the method for kinematic modeling of the biped walking robot, for synthesizing various gait trajectories, and for calculating adequate values of the joint torque inside the stable region. To synthesize various and anthropomorphic walking easily, the gait trajectory is specified by a set of ten walking prameters, and the trunk motion equation is derived by the zero moment point and the gait trajectory. By distributing ground reaction force and moment reduced at the zero moment point to the both feet, the joint torque equation can be derived readily, and according to this equation, the joint torque to stable walking can be computed.

• Proceedings of the Korean Information Science Society Conference
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• 1998.10c
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• pp.426-428
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• 1998

본 논문은 움직임 추정기법 중의 하나인 차영상 분석 기법을 기반으로한 이동 물체 추적 시스템을 제안한다. 실세계와 같은 복잡한 환경에서의 적응성을 높이기 위해 동적인 배경 추출 방법을 제안하고, 이를 바탕으로한 차영상 분석 기법을 이용하여 이동 물체를 탐지한 후 개선된 인공신경망의 경쟁학습 모델인 ART2 학습알고리즘을 이용하여 추적한다. 또한 이동 물체의 평가도 값이 아닌 RGB 컬러정보를 이용한 물체의 특징 벡터를 구한다. 이러한 특징 벡터들은 이동 물체의 모양이나 명암의 변화를 반영한다. 이러한 정보의 변화에 적응성을 갖게 하기위해 개선된 ART2를 사용한다. 그리고 실제 환경에서 보행자를 탐지, 추적하는 실험 결과 Gray 영상보다 정확한 추적이 가능하였다.

• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.2804-2807
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• 2000

This paper suggests a method of the forward dynamic analysis for the computer simulation on the analysis of the dynamic behavior for biped walking robot. The equations f motion of the system or the simulation are constructed by using the Method of the multibody dynamics which is powerful method for modeling of the complex biped system. For the simplicity of simulation, we consider that the sole of the contacting foot is affected by the reaction forces for tree structure system topology instead of the addition or deletion of the kinematic constraints. The ground reaction forces can be modeled using the simple spring and damper model at the three contacting points on the sole of the foot. For minimizing the errors of numerical integration, the number of equations of motion is minimized by adding the driving constraints or a controller instead of the direct driving torques.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2022.06a
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• pp.269-270
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• 2022

자율주행 자동차의 개발을 위해서는 다양한 기능 평가, 성능 평가, 안전성 평가 등이 필수적이다. 이러한 평가는 컴퓨터 시뮬레이션과 실제 주행을 통해 이뤄질 수 있으며, 현실의 도로 상황을 고려한 단위시험환경들을 조합 구성한 통합시험환경에서 수행하는 것이 일반적이다. 여기서 단위시험환경은 도로망 구성, 장애물, 표지판 등의 정보를 포함하는 정밀도로지도를 기반으로 주행차량수, 보행자, 기상환경, 동적 이벤트 요소 등을 고려하여 구성할 수 있다. 본 논문에서는 이러한 단위시험환경을 구성하기 위한 정밀도로지도 처리 방법을 소개한다. 구체적으로는 정밀도로지도 처리를 포함하는 데이터 파이프라인을 설계하고, 정밀도로지도 객체분석을 통해 시험환경의 특성 및 상호 유사성을 파악한다. 국토지리정보원에서 배포한 정밀도로지도를 사용하여 객체를 추출하고 분석하는 실험을 수행했으며 전반적인 동작 상태를 확인했다. 개발한 소프트웨어는 향후 자율주행 학습을 위한 단위 및 통합 시험환경 구축 및 법규 및 규제 대응 서비스 시나리오의 구성에 활용할 예정이다.

• Journal of the Korean Society of Physical Medicine
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• v.9 no.4
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• pp.447-454
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• 2014

PURPOSE: The aim of this study was to determine the effect of inclination treadmill training with dynamic stretching on the spasticity and gait of chronic stroke patients. METHODS: Twenty two subjects were randomly assigned to either an experimental group (EG, n=11) or a control group (CG, n=11). Both groups participated in a standard rehabilitation program; in addition, the EG participated in inclination treadmill training for 20 min per day, five times per week, for 4 weeks, and the CG participated in treadmill walking training for 20 min per day, five times per week, for 4 weeks. Outcome measurements, recorded before and post intervention. Walking ability was measured using the 10m walking test (10MWT) and Timed up and go (TUG) test. Spasticity of the medialis gastrocnemius was measured using a myotonometer. RESULTS: Significant differences were observed the both groups for walking ability and spasticity after the training program. The results of the study were follows: 10MWT and TUG was significantly increased in both groups (p<0.05) and it was also found to be significant between groups after intervention (p<0.05). Spasticity was significantly increased in both groups (p<0.05) and it was also found to be significant between the groups after intervention (p<0.05). CONCLUSION: These findings indicate that inclination treadmill training improves gait ability and reduces spasticity of the medialis gastrocnemius. Inclination treadmill training may be used as an easy, effective and accessible way to improve the walking ability and decrease spasticity in stroke patients. Further studies are necessary to generalize the findings of this study.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.5
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• pp.337-343
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• 2020

This study proposed piezoelectric ceramic bender actuators for application to small walking robots. As the space where human access has recently become increasingly restricted (e.g., highly concentrated radioactive storage areas, viral contaminated areas, terrorist zones, etc.), the scope of using robots is becoming more diverse, and many actions that were possible only in the past have been attempted to be replaced by small robots. This robotic concept has the advantage of being simple in structure, making it compact and producing a large size work force. The dynamic modeling, using finite element analysis, maximized the robot's mobility performance by optimizing the shape of the actuator, and the results were verified through fabrication and experimentation. The actuator moved at a maximum speed of 236 mm/s under no load conditions, and it could move at a speed of 156 mm/s under load conditions of 5g. The proposed actuator has the advantage of modular additions depending on the mission and required performance, which ensured that they are competitive against similar drive sources previously created.