• Archives of Reconstructive Microsurgery
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• 제12권2호
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• pp.119-124
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• 2003

Introduction : The purpose is a retrospective evaluation of the clinical results of the radial forearm flap transfer for foot reconstruction. Materials and methods : We evaluated 21 cases with medical records including etiology, wound dimension, presence of infection, associated fracture, ischemic time of free flap, complication of donor and recipient site. The final results were evaluated with our clinical score (walking, shoe-in, cosmetic). Results : Defects were located on the heel (12 cases), dorsum of foot (4 cases) and sole (5 cases). Mean wound dimension was $7.56{\times}6.0cm$, and mean ischemic time of free flap was 94.5minute. There were superficial skin necrosis (1 case), recurrent ulceration (2 cases) in recipient site, and no complication in donor site but complaint about cosmetic problem (3 cases). The clinical score showed excellent in 14 cases, good in 4 cases, fair in 1 case and poor in 2 cases. Conclusion : We consider the radial forearm flap could provid the stable and durable restoration of normal foot contour without debulking in the foot reconstruction and achieved normal ambulation and cosmetic satisfaction.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 추계학술대회논문집A
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• pp.576-583
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• 2000

A robust position control using a sliding mode controller is adopted for the stable dynamic walking of the biped. For the biped robot that is modeled with 14 degrees of freedom rigid bodies using the method of the multibody dynamics, the joint angles for simulation are obtained by the velocity transformation matrix using the given Cartesian foot and trunk trajectories. Hertz force model and Hysteresis damping element which is used in explanation of the energy dissipation during contact with ground are used for modeling of the ground reactions during the simulation. By the obtained that forces which contains highly confused noise elements and the system modeling uncertainties of various kinds such as unmodeled dynamics and parameter inaccuracies, the biped system will be unstable. For that problems, we are adopting a nonlinear robust control using a sliding mode controller. Under the assumption that the esimation error on the unknown parameters is bounded by a given function, that controller provides a successful way to preserve stability and achieve good performance, despite the presence of strong modeling imprecisions or uncertainties.

• 대한족부족관절학회지
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• 제2권2호
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• pp.82-87
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• 1998

The ankle is a complex structure supporting the entire musculoskeletal system during standing and walking. And so the goals of operative treatment for ankle fractures are to obtain an anatomical reduction that is maintained by stable fixation, resulting in a healed fracture and recovery of normal function. The 64 patients who had ankle fractures were treated by arthroscopic reduction(20 cases) and open reduction (43 cases) in Konkuk university hospital from February 1991 to October 1997 and the results were analyzed in clinical and radiological aspects. The following results were obtained. According to the criteria of Meyer, arthroscopic assisted reduction group had good or excellent results in 18 cases (90%) and open reduction group good or excellent in 35 cases (83%). The difference of the results was not significant statistically, but arthroscopic assisted reduction technique has several advantages over open technique; the best assessment of articular surface, lower wound problem, postoperatively faster rate of rehabilitation and minor discomfort.

• The Journal of Korean Physical Therapy
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• 제27권2호
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• pp.112-117
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• 2015

Purpose: The purpose of this study was to examine the effects of a task-specific obstacle crossing rehabilitation program on functional gait ability in patients with cerebellar ataxia. Overall, we sought to provide ataxia-specific locomotor rehabilitation guidelines for use in clinical practice based on quantitative evidence using relevant analysis of gait kinematics including valid clinical tests. Methods: Patients with cerebellar disease (n=13) participated in obstacle crossing training focusing on maintenance of dynamic balance and posture, stable transferring of body weight, and production of coordinated limb movements for 8 weeks, 2 times per week, 90 minutes per session. Throughout the training of body weight transfer, the instructions emphasized conscious perception and control of the center of body stability, trunk and limb alignment, and stepping kinematics during the practice of each walking phase. Results: According to the results, compared with pre-training data, foot clearance, pre-&post-obstacle distance, delay time, and total obstacle crossing time were increased after intervention. In addition, body COM measures indicated that body sway and movement variability, therefore posture stability during obstacle crossing, showed improvement after training. Based on these results, body sway was reduced and stepping pattern became more consistent during obstacle crossing gait after participation in patients with cerebellar ataxia. Conclusion: Findings of this study suggest that task-relevant obstacle crossing training may have a beneficial effect on recovery of functional gait ability in patients with cerebellar disease.

• 한국정밀공학회지
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• 제18권5호
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• pp.137-146
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• 2001

A robust controller with the sliding mode is proposed for stable dynamic walking of the biped robot in this paper. For the robot system to be controlled, which is modeled as 14 DOF rigid bodies by the method of multi-body dynamics, the joint angle trajectories are determined by the velocity transformation matrix. Also Hertz force model and Hysteresis damping element are utilized for the ground reaction and impact forces during the contact with the ground. The biped robot system becomes unstable since those forces contain highly confused noise components and some discontinuity, and modeling uncertainties such as parameter inaccuracies. The sliding mode control is applied to solve above problems. Under the assumption of the bounded estimation errors on the unknown parameters, the proposed controller provides a successful way to achieve the stability and good performance in spite of the presence of modeling imprecisions of uncertainties.

• 대한물리치료과학회지
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• 제2권4호
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• pp.739-747
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• 1995

The purpose of this study was to evaluate and compare the Limits of stability(LOS) in hemiplegic patients who can walking independently. The LOS was measured at stable surface, unstable surface with eye open and eye closed. In this study, 18 out-patients were evaluated who were treated at Yonsei University Medical Center Rehabilitation Hospital. In order to determine the statistical significance of results, T-test, paired t-test, and Kruskal-Wallis 1-way ANOVA were applied at 0.05 level of significance. The results were as follows: 1. The mean of lateral limits of stability was 9.89 degree. 2. The mean of anteroposterior limits of stability was 6.43 degree. 3. There was a significant difference of limits of stability between sound side and affected side(p<0.05). 4. The limits of stability was significantly decreased with eye closed(p<0.05) 5. The limits of stability was significantly decreased at unstable surface(p<0.05). 6. The limits of stability was a significant difference as spasticity degree of ankle plantar flexors(p<0.05). These results showed that the limits of stability in hemiplegic patients was more decreased than that of normal adult. In order to improve the balance in hemiplegic patients, we need to increase the limits of stability.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 B
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• pp.871-873
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• 1995

The purpose of this paper is to design and construct the compact type joint driver and controller of the biped robot. This biped robot will be designed to be suitable for the practical usages and applications in the work environment, which is not plat floor, like a stairs by taking the stand-alone style that equipped all the parts except power sources. Generally, highly nonlinear motion dynamics of the biped robot is realized to linear approximations by installing a high-ratio speed reducer at each joint and dividing motions into a several piecewise linear motions, which is realized by the digital controller design techniques. This biped robot has symmetrical structure to get the stable walking ability and also the hierachical structure to control each joint as well. That is, all of the joint controllers are connected to the main controller in the composition of overall controllers. The driver and controller of each joint uses PI controller that compensate the velocity and position errors by the data of the encoder. And the signal characteristics of each joint controller forms a trapezoid speed profile which is predefined by the values of direction, maximum velocity and position.

• 한국정밀공학회지
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• 제20권8호
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• pp.135-143
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• 2003

This paper presents the impact minimization of a biped robot by using genetic algorithm. In case we want to accomplish the designed plan under the special environments, a robot will be required to have walking capability and patterns with legs, which are in a similar manner as the gaits of insects, dogs and human beings. In order to walk more effectively, studies of mobile robot movement are needed. To generate optimal motion for a biped robot, we employ genetic algorithm. Genetic algorithm is searching for technology that can look for solution from the whole district, and it is possible to search optimal solution from a fitness function that needs not to solve differential equation. In this paper, we generate trajectories of gait and trunk motion by using genetic algorithm. Using genetic algorithm not only on gait trajectory but also on trunk motion trajectory, we can obtain the smoothly stable motion of robot that has the least impact during the walk. All of the suggested motions of biped robot are investigated by simulations and verified through the real implementation.

• 센서학회지
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• 제33권1호
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• pp.18-23
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• 2024

Humanoid robots, designed to interact in human environments, require stable mobility to ensure safety. When a humanoid robot falls, it causes damage, breakdown, and potential harm to the robot. Therefore, fall detection is critical to preventing the robot from falling. Prevention of falling of a humanoid robot requires an operator controlling a crane. For efficient and safe walking control experiments, a system that can replace a crane operator is needed. To replace such a crane operator, it is essential to detect the falling conditions of humanoid robots. In this study, we propose falling detection methods using Convolution Neural Network (CNN) model. The image data of a humanoid robot are collected from various angles and environments. A large amount of data is collected by dividing video data into frames per second, and data augmentation techniques are used. The effectiveness of the proposed CNN model is verified by the experiments with the humanoid robot MAX-E1.

• 한국임상수의학회지
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• 제32권2호
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• pp.148-153
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• 2015

본 연구는 비글견에서의 마취 효과에 있어서 isoflurane과 병용시에 두가지 opioid 약물을 비교, 아이소플루란/레미펜타닐과 아이소플루란/펜타닐 조합의 마취간의 차이를 알아보기 위하여 실시하였다. Isoflurane은 0.5 MAC으로 유지하고, opioid 약물은 등속으로 정맥 주입하였다. 각 개체에서 마취를 2시간 동안 유지한 뒤, isoflurane과 opioid 약물을 중단하고서 안구가 제 위치를 찾는 시간(eye global positioning time), 연하 반사가 나타나는 시간(gag reflex time), 머리를 드는 시간(head up time), 엎드림 자세가 나타나는 시간(sternal recumbency time), 서는 시간(standing time), 걷는 시간(walking time), 그리고 마취에서 완전히 회복된 시간(complete recovery time)을 기록하였다. 두가지 조합 모두 전 과정에 걸쳐 양호한 마취상태를 유지함과 동시에 빠를 회복 시간을 보여 비글견의 마취에 적합하였다. 한편, 회복 시간에 있어 아이소플루란/레미펜타닐 조합은 아이소플루란/펜타닐 조합에 비해 그 변동 계수가 낮아 좀 더 신뢰할 만한 것으로 나타났다. 따라서, 환자의 중등도가 높고, 안정적인 회복이 요구될 때에는 아이소플루란/레미펜타닐 조합의 마취가 더 좋은 선택일 것으로 생각된다.