• The Journal of Korean Physical Therapy
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• v.33 no.3
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• pp.136-141
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• 2021

Purpose: Dementia is a disease in which cognitive function declines, leading to deterioration of body functions and activities of daily living. The purpose of this study is to explore the effects of dual-task training, including cognitive tasks, on cognitive and body function and β-amyloid levels in Alzheimer's dementia patients. Methods: 34 inpatients diagnosed with Alzheimer's dementia at a nursing hospital located in South Korea. The patients were randomly divided into a dual-task group (n=16) and a single-task group (n=18). Each group was trained for 30 minutes three times a week for eight weeks. The MMSE-K was used to measure the patients' cognitive function. To assess the patients' static balance ability, their LOS was measured using BioRescue. while dynamic balance was measured using the BBS. The 10MWT were conducted to evaluate the patients' walking ability. Blood analysis was performed to measure levels of β-amyloid. Results: Both groups exhibited statistically significant improvements in gait function after the training (p<0.05). The dual-task group exhibited statistically significant differences in cognitive function, static and dynamic balance function, and β-amyloid levels after training (p<0.05). A significant difference was observed between the two groups (p<0.05). Conclusion: Dual-task training were found to be effective in improving cognitive and bodily functioning and reducing β-amyloid levels in Alzheimer's dementia patients. Thus, this may be suggested as an effective exercise method for the treatment and early prevention of Alzheimer's dementia.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.11
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• pp.3780-3797
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• 2022

The estimation of radio map (RM) is a fundamental and critical task for the network planning and optimization performance of mobile communication. In this paper, a RM estimation method is proposed based on a deep dual learning structure. This method can simultaneously and accurately reconstruct the urban building map (UBM) and estimate the RM of the whole cell by only part of the measured reference signal receiving power (RSRP). Our proposed method implements UBM reconstruction task and RM estimation task by constructing a dual U-Net-based structure, which is named RadioCycle. RadioCycle jointly trains two symmetric generators of the dual structure. Further, to solve the problem of interference negative transfer in generators trained jointly for two different tasks, RadioCycle introduces a dynamic weighted averaging method to dynamically balance the learning rate of these two generators in the joint training. Eventually, the experiments demonstrate that on the UBM reconstruction task, RadioCycle achieves an F1 score of 0.950, and on the RM estimation task, RadioCycle achieves a root mean square error of 0.069. Therefore, RadioCycle can estimate both the RM and the UBM in a cell with measured RSRP for only 20% of the whole cell.

• Physical Therapy Korea
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• v.17 no.3
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• pp.20-30
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• 2010

This study examined whether any changes by mental task types on postural control in chronic stroke persons. Sixteen chronic stroke persons (mean age=53.75 yr) and sixteen age-and gender-matched healthy controls (mean age=54.44 yr) took part in this study. Participants randomly performed three different tasks on the stable and unstable surfaces. The no mental task was to stand while holding a 100 g weight in each hand, the arithmetic task (mental task) was to perform a silent 1-backwards counting while standing and holding a 100 g weight in each hand, and the simple task (mental task) was to stand and hold with both hands a tray (200 g) on which a glass filled with water has been placed. Sway path and sway velocity of the center of pressure (COP) were measured to assess standing postural control by task performance using the force platform. According to the results, in stroke group, total sway path and total sway velocity of COP was significantly decreased during arithmetic and simple task compared to no mental task on the stable surface (p<.05), and sway path (anteroposterior AP, mediolateral ML) of COP, total and sway velocity (AP, ML, total) of COP was significantly decreased during arithmetic and simple task compared to no mental task on the unstable surface (p<.05). Especially, sway path (AP, total) of COP and sway velocity (AP, ML, total) of COP was significantly decreased under the simple task when compared to the arithmetic task on the unstable surface (p<.05). In healthy control group, sway path (AP, ML, total) of COP and sway velocity (AP, ML, total) of COP was significantly decreased during arithmetic and simple task compared to no mental task on the stable and unstable surface (p<.05), and sway path (AP, total) of COP and sway velocity (AP, ML, total) of COP was significantly decreased under the simple task when compared to the arithmetic task on the unstable surface (p<.05). In conclusion, the findings of this study showed that arithmetic and simple task improved standing postural control for chronic stroke patients and the type of arithmetic and simple tasks were critical factor that reduced standing postural sway in dual-task conditions. Future research should determine whether dual-task conditions, including simple task, would be effective as a training program for standing postural control of stroke patients.

• The Journal of Korea Robotics Society
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• v.17 no.2
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• pp.164-171
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• 2022

Recently, interest of a dual arm robot which can replace humans is increasing in order to improve the working environment and solve the labor shortage. Various studies related with design and analysis of dual-arm robots have been conducted because dual arm robots can have various kinematic configurations according to the objective task. It is necessary to evaluate the work performance according to various kinematic structures of the dual arm robot to maximize its effectiveness. In the paper, the performance analysis is studied according to the shoulder configuration and the wrist configuration of the dual-arm robot by using main performance indices such as manipulability, condition number, and minimum singular value by assigning proper weight values to each objective motion. Performance analysis for the robotic assembly process is effectively carried out for each representative dual arm robot configuration.

• 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.

• Therapeutic Science for Rehabilitation
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• v.5 no.1
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• pp.23-32
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• 2016

Objective : To investigate the current international researches which identify the effect of stroke with hemiplegia after dual-task training Methods : We systematically examined journals published from 2007 to 2015, searching PubMed. Total 5 researches were selected for the analyses. Results : Selected studies were all in international journal and they used two group experimental design. In addition, all the paper got PEDro scores above 6. They conducted gait task for motor task, at the same time used various domain of cognitive task such as from sustain attention to working memory. The outcome measure tools used for evaluation by the standardized assessment tool and operational definition, further also included the assessment tool designed for the dual-task training such as a variety of tools make possible to assess various aspects of effect. Discussion : Dual-task training in this study was found to give a positive effect on the dual-task performance, as well as improving the motor and cognitive function in patients with stroke. However there were also limitation to the studies conducted so far. In order to apply the occupational therapy, this results can consider as the preliminary data which suggest supplement point and can be a evidence for effective treatment for stroke with hemiplegia.

• Journal of Korean Institute of Industrial Engineers
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• v.10 no.2
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• pp.3-16
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• 1984

This study develops a scientific method in pilot selection by analysing a divided attention performance between the successful pilots and the failures in a flight training course. To measure the divided attention performance, Dual Task Method is used in which the primary task is a tracking task while the secondary tasks are, 1. short term memory task, 2. choice reaction task and 3. judgement task. Result shows that the performance of the pilots is significantly better (P < 0.1) than that of the failures in dual performance. In addition, the differences in the divided attention performance between the two groups are increased in proportion to the difficulty of the task and especially in the Short Term Memory, the increment is most dramatic.

• Therapeutic Science for Rehabilitation
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• v.9 no.4
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• pp.69-81
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• 2020

Objective : The purpose of this study was to develop a Yonsei dual task cognitive screening test (Y-DuCog) for the elderly. Methods : The reliability and validity test of Y-DuCog (Yonsei Dual Task Cognitive Screening Test) was developed by 229 elderly people aged over 60 years from community organizations at Gyeonggi-do and Chungcheong-do from May 2019 to August 2019. In addition, the criteria for classifying elderly with cognitive impairment were presented. Results : The correlation analysis between MMSE-K, MoCA-K and Y-DuCog were a correlation between the DTE and CRR of Y-DuCog. As a result of internal consistency, Cronbach's-α values of DTE and CRR showed .848 (p<.01) and .916 (p<.01), respectively. The test-retest reliability was high. The screening point showed 88.7% sensitivity and 83.5% specificity at 31.76 seconds in total DTE, and 84.5% sensitivity and 76.6% specificity at 0.38 in total dual-task CRR. Conclusion : This study verified the reliability and validity of Y-DuCog. It was found that the level of education was not a barrier to the undertaking of this test. Furthermore, the test could be performed easily and quickly. It is also expected to be used to evaluate the effectiveness of cognitive function assessment and intervention methods in the elderly.

• Journal of the Korean Society of Physical Medicine
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• v.6 no.4
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• pp.465-473
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• 2011

Purpose : This study was to evaluate gait velocity and muscle activity on 3 different gait conditions in elderly women. Methods : There were one group was 20's generation(n=12), and the other group was over 60's generation (n=12). The velocity of gait was analysed for using the Footscan system, EMG(MP150) for muscle activity. Subjects were measured 3 gait condition(normal, obstacle-10cm, dual obstacle-10cm. Measured values were used by the independent t-test for analysing between groups, and repeated measurement of ANOVA for analysing within group. Results : The results were as follow: velocity and acticities of lower 4 muscles were significantly differences in experimental group. In control group, there were not significantly differences. Contrast-groups were significantly differences of velocity(obstacle, dual obstacle), muscle activities(soleus-dual obstacle, hamstring-all). Conclusion : These results indicate that elderly people are reduced gait ability in dual task, and obstacle gait. So Elderly women need to training obstacle/dual gait for preventing falling.

• PNF and Movement
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• v.17 no.3
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• pp.339-351
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• 2019

Purpose: This study identified the effects of dual-task gait training on balance, gait function, and activity of daily living in patients with Parkinson's disease. Methods: This study used a single-subject design. Two patients with Parkinson's disease participated in this study. Dual-task gait training was performed 1 hour per day 8 times during intervention phase. The subjects were measured 8 times in the baseline phase, 8 times in the intervention phase, and 8 times in the follow-up phase. The outcome measurements included a timed up and go test (TUG), a Berg balance scale (BBS), a 10 meter walk test (10MWT), a 6 minute walk test (6MWT), a dynamic gait index (DGI) and a Korean modified Barthel index (K-MBI). Results: When compared to the average of the baseline process, the data collected during the intervention period showed that the TUG and 10MWT results improved and the tendency line was above the baseline. In addition, BBS, 6MWT, DGI, and K-MBI values for both patients increased remarkably after the training. Conclusion: The results of this study revealed that dual-task gait training may be helpful to improve balance, walking function, and activity of daily living for patients with Parkinson's disease. Further studies need to confirm our findings.