• International Journal of Control, Automation, and Systems
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• v.6 no.1
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• pp.101-108
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• 2008

The transposed Jacobian is proposed to transform the control space from task space to joint space, in this paper. Instead of inverse Jacobian, the transposed Jacobian is preferred to avoid singularity problem, short real time calculations and its generality to apply for rectangular Jacobian. On-line Jacobian identification is proposed to cancel parametric errors produced by D-H parameters of manipulator. To identify Jacobian, the joint angles and the end-effector position are measured when tracking a desired trajectory in task space. Stability of control system is analyzed. The control system is simulated for position control of a two-link manipulator driven by permanent magnet dc motors. Simulation results are shown to compare the roles of inverse Jacobian and transposed Jacobian for transforming the control space.

• Journal of The Korean Society of Integrative Medicine
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• v.9 no.4
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• pp.211-223
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• 2021

Purpose : The purpose of this study was to examine the effect of task-oriented circuit training using unstable support surface on balance, gait ability, and balance confidence in subacute stroke patients. Methods : Forty-five patients with subacute stroke were randomly divided into the three following groups of 15: 1) TOCT-US group; task-oriented circuit training using unstable surface (experimental group 1), 2) TOCT-SS group; task-oriented circuit training using stable surface (experimental group 2), and 3) CON group; conventional physical therapy (control group). All patients participated in one of the three training programs for 6 weeks, 30 minutes per session, 3 times per week. Patients' balance ability was assessed using the BT-4, BBS (berg balance scale), TUG (time up and go test), and LOS (limit of stability). Gait speed was measured to examine gait ability. K-ABC (activities-specific balance confidence scale) was also used to assess the level of patients' confidence in daily activities. Results : After the intervention, the sway area in experimental groups 1 and 2 decreased, but that in the control group increased. Experimental group 1 showed significant improvement compared with experimental group 2 and the control group. BBS, TUG, and LOS scores of experimental group 1 were significantly improved compared with those of experimental group 2 and the control group. Also, gait speed significantly improved in experimental group 1 compared with experimental group 2 and the control group. Experimental groups 1 and 2 showed significant improvement in K-ABC scores after training. Conclusion : Patients with subacute stroke had significantly improved balance, gait, and level of confidence in performing activities of daily living following task-oriented circuit training using the unstable surface. This indicates that task-oriented circuit training using unstable surfaces can be an effective treatment method for the recovery of balance and gait in subacute stroke patients.

• Journal of the Korean Society of Physical Medicine
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• v.8 no.1
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• pp.1-9
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• 2013

PURPOSE: This study compared the effects of dual motor task training and simple task training on the balance of subacute stroke patients. METHODS: A total of 23 subacute stroke patients participated in the study. The subjects were allocated randomly to two groups: an experimental group and a control group. Both groups received conventional treatment for 50 minutes, 5 times per week for 6 weeks. In addition, the experimental group stacked blocks, moved catch cups, and moved rings while standing and gait. To evaluate the effects of the exercises, subjects were evaluated by using the balance system and the timed get up and go test(TUG) for balance measurement. The data was analyzed using a paired t-test and independent t-test to determine the statistical significance. RESULTS: The experimental group showed a significant decrease on the medial-lateral and anterior-posterior stability index compared to the control group (p<.05) for the simple task and a significant decrease on the medial-lateral and anterior-posterior stability index compared to the control group for the dual task. In addition, the experimental group showed a significant increase in TUG time compared to the control group (p<.05). CONCLUSION: These results support the perceived benefits of dual motor task training to augment the balance of subacute stroke patients. Therefore, dual motor task training is recommended for subacute stroke patients.

• Animal cells and systems
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• v.7 no.4
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• pp.303-307
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• 2003

The aim of this study is to investigate whether alcohol alters learning and memory processes pertaining to emotional and spatial factors using the active avoidance and T-maze task in zebrafish. In the active avoidance task, zebrafish were trained to escape from one compartment to another to avoid electric shocks (unconditioned stimulus) following a conditioned light signal. Acquisition of active avoidance task appeared to be normal in zebrafish that were treated with 1% alcohol for 30 min for 17 days until the end of the behavioral test, and retention ability of learned behavior, tested 2 days later, was the same as control group. In the T-maze task, the time to find a reservoir was compared. While the latency was similar during the 1 st training session between control and alcohol-treated zebrafish, it was significantly longer in alcohol-treated zebrafish during retention test 24 h later. Furthermore, when alcohol was treated 30 min after 2nd session without prior treatment, zebrafish demonstrated similar retention ability compared to control. These results suggest that chronic alcohol treatment alters spatial learning of zebrafish, but not emotional learning.

• Journal of the Korean Society of Physical Medicine
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• v.5 no.4
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• pp.509-515
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• 2010

Purpose : This study was performed to examine the effect of stimulation task-oriented training on the balance ability of the hemiplegic patients caused by stroke. Methods : We made a random sampling of 25 hemiplegic patients caused by stroke. 10 patients(experimental group)were treated by simulation Task-oriented training and Conventional training used by balance pad. The other 10 patients(control group) were only treated by Conventional training used by balance pad. During the training, 3 patients from the experimental group and 2 patients from the control group were excluded by private affairs. The control group has done Conventional training 6 times a week for 6 weeks. And experimental group has done Simulation task-oriented training two times, conventional training four times a week for 6 weeks. Balance ability was assessed by Fuctional Reaching Test (FRT) : unilateral and bilateral reaching. Results : In comparison of FRT before and after training, two groups all was significantly improved(p<.05). But bilateral reaching variation was significantly improved in experimental group. Conclusion : we can use simulation Task-oriented training valuably to increase balance ability of hemiplegic patients.

• Korean Journal of Adult Nursing
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• v.27 no.6
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• pp.707-717
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• 2015

Purpose: This study was to develop and verify the effects of the exercise-cognitive combined dual-task training program on cognitive function and depression of the elderly with mild cognitive impairment (MCI). Methods: A non-equivalent control group pretest-posttest design was used. The participants were assigned into two groups: an experimental group receiving an exercise-cognitive combined dual-task (n=20) and a control group receiving a simple-task (n=18). After 8 weeks of intervention (2 days per week), the change in depression and cognitive functions were compared between the groups. Results: General cognitive function (t=-2.81, p=.011), frontal cognitive function (Z=-3.50, p<.001), attention/working memory function (U=-2.91, p=.004), depression (t=4.96, p<.001) of the experimental group were significantly increased than those of the control group. Conclusion: The findings of the study showed that an exercise-cognitive combined dual-task program for MCI was effective in improving general cognitive function, frontal and executive function, attention/working memory function, and reducing depression.

• PNF and Movement
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• v.10 no.1
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• pp.25-33
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• 2012

Purpose : The purpose of this study was to compare the effect of treadmill training and cognitive task with in the course of treadmill training at the same time with chronic stroke patients. Methods : Fourteen chronic stroke patients participated. Participants were randomly assigned to the control and experimental group(7 experimental, 7 control). All of participants were in-patients at local hospital and had been receiving a traditional rehabilitation program, five days a week. The both groups have undergone 4weeks. The experimental group trained in treadmill and cognitive task at the same time, but control group trained only treadmill. 10m walking test, Timed Up & Go (TUG) test and 6 Minutes walking(6M walking) test to measure the walking speed, dynamic balance and waling endurance ability were carried out before and after the training. Results : The result of the study were as follow:10m walking test were significantly increased both groups(p<.01), but not significant between groups(p>.05). TUG test were significantly increased both groups(p<.001) and between groups(p<.01). 6M walking test were significantly increased both groups(p<.001), but not significant between groups(p>.05). Conclusion : Ahead of return to the community to patients with stroke, cognitive task with in the course of treadmill training at the same time was effective in improving the dynamic balance ability.

• Proceedings of the Korea Society of Information Technology Applications Conference
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• 2005.11a
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• pp.229-232
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• 2005

In this paper, an image-based "approach-align -grasp" visual servo control design is proposed for the problem of object grasping, which is based on the binocular stand-alone system. The basic idea consists of considering a vision system as a specific sensor dedicated a task and included in a control servo loop, and we perform automatic grasping follows the classical approach of splitting the task into preparation and execution stages. During the execution stage, once the image-based control modeling is established, the control task can be performed automatically. The proposed visual servoing control scheme ensures the convergence of the image-features to desired trajectories by using the Jacobian matrix, which is proved by the Lyapunov stability theory. And we also stress the importance of projective invariant object/gripper alignment. The alignment between two solids in 3-D projective space can be represented with view-invariant, more precisely; it can be easily mapped into an image set-point without any knowledge about the camera parameters. The main feature of this method is that the accuracy associated with the task to be performed is not affected by discrepancies between the Euclidean setups at preparation and at task execution stages. Then according to the projective alignment, the set point can be computed. The robot gripper will move to the desired position with the image-based control law. In this paper we adopt a constant Jacobian online. Such method describe herein integrate vision system, robotics and automatic control to achieve its goal, it overcomes disadvantages of discrepancies between the different Euclidean setups and proposes control law in binocular-stand vision case. The experimental simulation shows that such image-based approach is effective in performing the precise alignment between the robot end-effector and the object.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.4
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• pp.376-380
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• 2008

This paper deals with a performance analysis of real-time control systems, which engages DMR(dual modular redundancy) to detect transient errors and checkpointing technique to tolerate transient errors. Transient errors are caused by transient faults and the most significant type of errors in reliable computer systems. Transient faults are assumed to occur according to a Poisson process and to be detected by a dual modular redundant structure. In addition, an equidistant checkpointing strategy is considered. The probability of the successful task completion in a real-time control system where periodic checkpointing operations are performed during the execution of a real-time control task is derived. Numerical examples show how checkpoiniting scheme influences the probability of task completion. In addition, the result of the analysis is compared with the simulation result.

• Proceedings of the KIEE Conference
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• 2003.07d
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• pp.2362-2364
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• 2003

In this paper, behaviors performing controls of a mobile robots are designed based on the concept of closed-loop controls. A control architecture, in which the behaviors coordinate concurrently with one others to achieve a task is also proposed. In the control architecture, task manager allocates valid resources and configures the weight of the behavior outputs to achieve the task. For practical implementation, a rate modulation strategy based on RMS(Rate Modulation Strategy) is proposed for efficient resource allocations. The rate modulation strategy is performed with considering control stability. The efficiency of the proposed rate modulation strategy is validated through simulation tests.