• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1464-1468
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• 2004

This paper presents a learning controller for repetitive gait control of biped walking robot. We propose the iterative learning control algorithm which can learn periodic nonlinear load change ocuured according to the walking period through the iterative learning, not calculating the complex dynamics of walking robot. The learning control scheme consists of a feedforward learning rule and linear feedback control input for stabilization of learning system. The feasibility of learning control to biped robotic motion is shown via dynamic simulation with 12-DOF biped walking robot.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.11
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• pp.2266-2268
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• 2009

In this paper, a simple method of angle velocity estimation is presented for a passive dynamic biped robot. The estimation problem is not an easy task because its dynamic model is a hybrid system involved with an impact condition. Instead of designing a complex observer for hybrid systems we simply utilize the impact condition to reset the initial condition of the high-pass filter when the non-support leg hits the slope. The approach has been verified by simulation results.

• Advances in robotics research
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• v.2 no.2
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• pp.151-159
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• 2018

The evolution of bipedal robots was the foundation stone for development of Humanoid robots. The highly complex and non-linear dynamic of human walking made it very difficult for researchers to simulate the gait patterns under different conditions. Simple controllers were developed initially using basic mechanics like Linear Inverted Pendulum (LIP) model and later on advanced into complex control systems with dynamic stability with the help of high accuracy feedback systems and efficient real-time optimization algorithms. This paper illustrates a number of significant mathematical models and controllers developed so far in the field of bipeds and humanoids. The key facts and ideas are extracted and categorized in order to describe it in a comprehensible structure.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.10
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• pp.2627-2642
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• 2023

Parkinson's disease (PD) is a typical, chronic neurodegenerative disease involving the concentration of dopamine, which can disrupt motor activity and cause different degrees of gait disturbance relevant to PD severity in patients. As current clinical PD diagnosis is a complex, time-consuming, and challenging task that relays on physicians' subjective evaluation of visual observations, gait disturbance has been extensively explored to make automatic detection of PD diagnosis and severity rating and provides auxiliary information for physicians' decisions using gait data from various acquisition devices. Among them, wearable sensors have the advantage of flexibility since they do not limit the wearers' activity sphere in this application scenario. In this paper, an attention-based temporal network (ATN) is designed for the time series structure of gait data (vertical ground reaction force signals) from foot sensor systems, to learn the discriminative differences related to PD severity levels hidden in sequential data. The structure of the proposed method is illuminated by Transformer Network for its success in excavating temporal information, containing three modules: a preprocessing module to map intra-moment features, a feature extractor computing complicated gait characteristic of the whole signal sequence in the temporal dimension, and a classifier for the final decision-making about PD severity assessment. The experiment is conducted on the public dataset PDgait of VGRF signals to verify the proposed model's validity and show promising classification performance compared with several existing methods.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.792-795
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• 2007

To quantify irregular body motions the time series analysis was applied to the gait study. The motions obtained from gait experiment are complex to exhibit nonlinear behaviors. The purpose of this study is to measure quantitatively the characteristics of the major six joints of the body during walking. The gait experiments were carried out for eighteen young males walking on a motor driven 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 largest Lyapunov exponent was calculated from the time series to quantify stabilities of each joint. The results provides a data set of nonlinear dynamic characteristics for six joints engaged in normal walking.

• Physical Therapy Korea
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• v.18 no.2
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• pp.43-51
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• 2011

Balance is a complex motor skill that depends on interactions between multiple sensorimotor processes and environmental and functional contexts. Many rehabilitation specialists believe that balance assessment under multitask conditions may be a more sensitive indicator of balance problems and falls than balance assessment in a single-task context. Functional Gait Assessment has many tasks that allow for testing under multitask conditions. The purpose of this study was to determine the concurrent validity between the Functional Gait Assessment (FGA), Berg Balance Scale (BBS), and Timed "Up & Go" Test (TUG) in patients with stroke. One hundred and five participants with at least 3 months post stroke and able to walk at least 6 m with or without a mono cane, participated in this study. Concurrent validity between the FGA, BBS, and TUG was assessed using Spearman rank order correlation. The FGA correlated with the BBS (r=.80, p<.01) and TUG (r=-.77, p<.01). The good and moderate correlation between the FGA, BBS, and TUG establishes the concurrent validity of the FGA in patients with stroke. These measures provide clinicians with valuable information about patients' functional balance capabilities.

• Journal of Biomedical Engineering Research
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• v.28 no.3
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• pp.377-386
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• 2007

Mechanical loading to bone cells using simple sine wave or constant wave fluid flow has been widely used for in vitro experiments. Human gait is characterized by a complex loading to bones of lower extremities which results from a series of events consisting of heel strike, foot flat and push-off during the stance phase of the gait cycle. Telemetric force analyses have shown that human femora are subject to multiphasic loading. Therefore, it would be ideal if the physiologic loading conditions during human walking can be used for in vitro mechanotransduction studies. Here, for a mechanotransduction study, we develop it fluid flow system (FFS) in order to simulate human physiologic mechanicalloading on bone cells. The development methods of the FFS including the COR (Center for Orthopedic Research), monitor program are presented. The FFS could generate various multiphasic loading conditions of human gaits with output flow. Wall shear distribution was very uniform, with 81 % of the effective loading area of the culture on a glass slide. Our results demonstrated that the FFS, provide a new translational approach for unveiling molecular mechanotransduction pathways in bone cells.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.11
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• pp.4374-4381
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• 2010

The purpose of this research was to investigate the effects of complex exercise program for upper extremity function and balance proficiency in person with stroke. The subject in this study was a 68 year old woman with left hemiplegia after stroke, and the study period was from April 16th, 2005 to August 30, 2007. Complex exercise program was compromised of range of motion exercises, strengthening exercises, and repetitive task-oriented activities and so on, and the subject performed exercises three times a week, one hour a day. The upper extremity function of the subject was evaluated by the Brunnstrom Hand Recovery Stage, the Brunnstrom Upper Extremity Recovery Stage, the Fugl-Meyer Assessment of Motor Function, and the Manual Function Test, and the balance proficiency was measured by the Tinetti Gait & Balance Scale, and the One Leg Standing Test. The results indicated that the upper extremity test scores were all improved, the balance proficiency test marks were maintained and improved, therefore complex exercise program was effective method to forward upper extremity and balance proficiency in person with stroke.

• Journal of the Korean Society of Physical Medicine
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• v.18 no.3
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• pp.39-45
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• 2023

PURPOSE: This study aimed to provide the basic data necessary for rehabilitation by identifying the effects of complex balance exercises combined with self-observation training on balance and gait improvement in stroke patients. METHODS: This study assigned 20 people randomly into two groups: the control and experimental groups. The experimental group (10 subjects) underwent self-observation training-combined complex balance exercise. The control group (10 subjects) underwent complex balance exercises. A pretest of the balance ability and walking ability of both groups was performed. The interventions were conducted for 30 minutes three times a week for four weeks, and post-tests were conducted four weeks after all interventions were completed. RESULTS: There was a significant difference between the experimental and control groups according to the increase in Berg Balance Sale within the group and a statistically significant difference by a decrease in 10MWT (p < .01). On the other hand, there was a significant difference only in the change in Berg Balance Sale between the two groups (p < .05). CONCLUSION: Combined balance exercise combined with self-observation training and combined balance exercise alone positively affected the Berg Balance Sale and 10MWT in both groups. On the other hand, in the results between groups, there was a statistically significant difference in Berg Balance Sale in complex balance exercise combined with self-observation training. Therefore, self-observation training should be used for the rapid social rehabilitation of stroke patients.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.24 no.2
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• pp.69-74
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• 2018

Background: The purpose of this study was to investigate the effect of a complex exercise program for elderly people who had experienced a fall on their balance ability and proprioception when their visual sense was blocked. Methods: The subjects were 24 elderly people with experienced fall. They were equally and randomly divided into a blind group and a general group. The subjects performed the complex exercise program for 30 minutes, twice a day, five days a week for 4 weeks a total of 20 times. Outcome measures were the 10-meter walking test (10MWT), Berg balance scale (BBS), Fukuda stepping test(FST), proprioception test (PT). Results: After the intervention, the blind group showed improvements in 10MWT, BBS, FST, PT. The general group showed improvements in 10MWT and PT. Conclusions: The complex exercise program for elderly people helped enhance their balance ability and proprioception.