• International conference on construction engineering and project management
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• 2020.12a
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• pp.257-264
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• 2020

Objective: To investigate test-retest reliability and responsiveness of Equivital Lifemonitor and photoplethysmography based wristwatch tools in assessing physiological parameters during a simulated fatigue task. Methods: Ten university students (Mean age, 30.6 ± 1.7 years) participated in this pilot study. Participants were asked to perform a 30-minute of a simulated fatigue task in an experimental setup in a lab. The physiological parameters (e.g., heart rate, heart rate variability, respiratory rate, electrodermal activity, and skin temperature) were measured at baseline and immediately after the fatigue task. An intraclass correlation coefficient (ICC2,1) was used to evaluate the test-retest reliability of each tool in assessing physiological measures. In addition, the responsiveness of each tool to measure changes from baseline to posttest was calculated using a standardized response mean. Results: The Equivital Lifemonitor has shown good to excellent test-retest reliability for the assessment of heart rate (ICC, 0.97), heart rate variability (ICC, 0.86), respiratory rate (ICC, 0.77), and local skin temperature (ICC, 0.76). However, photoplethysmography based wristwatch showed moderate to good test-retest reliability for the assessment of heart rate (ICC, 0.71), heart rate variability (ICC, 0.73), electrodermal activity (ICC, 0.80), and skin temperature (ICC, 0.72). A large standardized response mean (>0.8) indicates that both tools can capture the changes in heart rate, heart rate variability, respiratory rate, skin temperature, and electrodermal activity after a 30-minute of fatigue task. Conclusions: The Equivital Lifemonitor and photoplethysmography based wristwatch devices are reliable in measuring physiological parameters after the fatigue task. Additionally, both devices can capture the fatigue response after a simulated construction task. Future field studies with a larger sample should investigate the sensitivity and validity of these tools in measuring physiological parameters for fatigue assessment at construction sites.

• 한국노년학
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• v.36 no.4
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• pp.1109-1124
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• 2016

We examined the effect of stereotype threat (STT) on spatial working memory and facial emotion recognition in Korean elderly. In addition, we investigated the role of expected moderator such as self-perception of aging. Seventeen seniors (male=7) received basic cognitive tests including K-WMS-IV, MMSE and answered self-report questionnaires including self-perception of aging, anxiety of aging, attitude toward aging and age identity on the first visit. On the second visit, they were exposed to negative stereotype by reading a script detailing cognitive decline related to aging while a control group was exposed to a neutral content. Following the exposure, they were tested on a spatial-working memory task (Corsi-block tapping task) and emotion recognition task (facial expression identification task). The results showed that the seniors exposed to STT showed significantly lower performance on emotion recognition task (p < .05) (i.e., especially on the more difficult facial stimuli). In addition, there was a significant interaction between STT and self-perception of aging (p< .05), indicating that those who have positive self-perception of aging did not show impairment in emotion recognition task and difficult spatial working memory task under STT. On the other hand, those with negative self-perception of aging showed impaired performance under STT. Taken together, the current study suggests that being exposed to STT could negatively influence cognitive and emotional functioning of elderly. Interestingly, having a positive self-perception of aging could protect the underperformance caused by STT.

• The Journal of Korean Physical Therapy
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• v.26 no.3
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• pp.191-195
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• 2014

Purpose: The purpose of this study is to investigate whether types of sensory-stimuli cues in terms of visual, auditory, and visuoauditory cues can be affected to motor sequential learning in healthy adults, using serial reaction time task. Methods: Twenty four healthy subjects participated in this study, who were randomly allocated into three groups, in terms of visual-stimuli (VS) group, auditory-stimuli (AS) group, and visuoauditory-stimuli (VAS) group. In SRT task, eight Arabic numbers were adopted as presentational stimulus, which were composed of three different types of presentational modules, in terms of visual, auditory, and visuoauditory stimuli. On an experiment, all subjects performed total 3 sessions relevant to each stimulus module with a pause of 10 minutes for training and pre-/post-tests. At the pre- and post-tests, reaction time and accuracy were calculated. Results: In reaction time, significant differences were founded in terms of between-subjects, within-subjects, and interaction effect for group ${\times}$ repeated factor. In accuracy, no significant differences were observed in between-group and interaction effect for groups ${\times}$ repeated factor. However, a significant main effect of within-subjects was observed. In addition, a significant difference was showed in comparison of differences of changes between the pre- and post-test only in the reaction time among three groups. Conclusion: This study suggest that short-term sequential motor training on one day induced behavioral modification, such as speed and accuracy of motor response. In addition, we found that motor training using visual-stimuli cue showed better effect of motor skill acquisition, compared to auditory and visuoauditory-stimuli cues.

• Journal of the Ergonomics Society of Korea
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• v.23 no.1
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• pp.23-38
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• 2004

This study examines different types of navigation aids when a navigator performs target search tasks in Virtual Environments. The factors manipulated in this study include target information (None/Landmark). navigational difficulty (Easy/Difficult). and map types (None/2D Map/3D Map). Navigation performance was measured by using task completion time and the number of target locations that was remembered by the navigator. In addition, user satisfaction on the navigation aids was also measured by using a 7-point Likert's scale. The results showed that the user satisfaction on the landmark was high when the 3D Map was provided. The task completion time shortened when navigational difficulty was set at "easy." The number of remembered target locations was large when there was no landmark. It was also large with an easy navigation task. or a map (20 or 3D) provided. Guidelines for selecting navigation aids were proposed based on the results.

• Journal of the Ergonomics Society of Korea
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• v.29 no.6
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• pp.943-949
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• 2010

When PCB soldering is performed with microscope due to the electronic components' microminiaturization, workers' awkward upper body postures and difficulties being in focus among lens, object and eyes are one of reasons for productivity decline. The object of this study is to investigate the level of difficulties of work and the extent of productivity improvement by changing work interfaces from the work using microscope to the work using LCD monitor. Independent variables was usage of microscope and image system and dependent variables were upper body segments including neck, shoulder, back, and waist, task convenience and eye fatigue. The Visual Analogue Scale (10cm) was used for questionnaire and one way ANOVA (two levels) and two sample t-test were conducted. In addition, RULA rating was conducted for working postures. The result showed that interface changes of LCD monitor, suggested by productivity comparison per one Man Hour, highly contributed to work convenience and productivity improvement.

• Journal of the Korean Society of School Health
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• v.35 no.1
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• pp.31-39
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• 2022

Purpose: The purpose of the study was to examine the meditating effect of unconditional self acceptance on the relationship between life stress and depression in nursing students. Methods: Data was collected from a survey of 140 nursing students using self-reported questionnaires. The data was analyzed using IBM SPSS Statistic 25.0. The mediating effect of unconditional self-acceptance on the relationship between the subject's life stress and depression was analyzed using Baron and Kenny's method. In addition, the Sobel test was conducted to determine the significance of the mediating effect. Results: The regression model explained 43% of the variance in nursing students' depression. Significant factors were task-related life stress, unconditional self acceptance, and academic achievement. Unconditional self acceptance had a partial mediating effect on the relationship between nursing students' task-related life stress and depression. Conclusion: To prevent depression in nursing students, it is necessary to build effective strategies to manage task-related stress and improve unconditional self-acceptance.

• ETRI Journal
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• v.45 no.4
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• pp.627-635
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• 2023

In vehicular edge computing (VEC) networks, the rapid expansion of intelligent transportation and the corresponding enormous numbers of tasks bring stringent requirements on timely task offloading. However, many tasks typically appear within a short period rather than arriving simultaneously, which makes it difficult to realize effective and efficient resource scheduling. In addition, some key information about tasks could be learned due to the regular data collection and uploading processes of sensors, which may contribute to developing effective offloading strategies. Thus, in this paper, we propose a model that considers the deterministic demand of multiple tasks. It is possible to generate effective resource reservations or early preparation decisions in offloading strategies if some feature information of the deterministic demand can be obtained in advance. We formulate our scenario as a 0-1 programming problem to minimize the average delay of tasks and transform it into a convex form. Finally, we proposed an efficient optimal offloading algorithm that uses the interior point method. Simulation results demonstrate that the proposed algorithm has great advantages in optimizing offloading utility.

• The Journal of Korean Physical Therapy
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• v.23 no.3
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• pp.7-12
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• 2011

Purpose: The cane is one of the most popular assistive devices for stroke patients. Clinical complaints of sensorimotor functions on the ipsilateral upper limb were appealed in stroke patients who had used a cane for a long period. Therefore, we investigated whether cane usage for a long-term period affected sensoriomotor dysfunctions on the non-affected upper limb, in terms of pain presence, shoulder joint sense, a nine-hole pegboard test, and a tracking task. Methods: We recruited 12 stroke patients, who were divided into the cane-using (CU) group or the non-cane using (NCU) group, according to cane usage experience. We evaluated joint position sense for the integrity of proprioceptive reposition sense in the shoulder joint, used a nine-hole pegboard test for upper limb dexterity evaluation, and a tracking task for visuomotor coordination. Results: Four patients in the CU group had complained of shoulder pain none did in the NCU group. In addition, the CU group showed more reposition errors on the shoulder joint than the NCU group did. In addition, the CU group had more difficulty in proprioceptive sense perception and in performance of the nine-hole pegboard teat and tracking task, compared with the NCU group. Conclusion: Our findings suggest that cane usage for a long period in stroke patients could give rise to trigger joint pain and decrease proprioceptive sense. In addition, complex motor performance in the ipsilateral upper limb could deteriorate. In stroke patients who had used acane for long period, careful observation and proper intervention will be necessary.

• School Mathematics
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• v.18 no.4
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• pp.749-771
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• 2016

The purpose of this study is to analyze mathematical tasks of Korea and the USA textbooks focused on conditions for parallelograms. In this study, structures of task, types of proof and reasoning, and levels of cognitive demand are investigated. The conclusion is as follows: First, with respect to structures of task, structures presented in the USA textbooks are more diverse. Second, with respect to types of proof and reasoning, Korea and the USA prefer IC task and DA task. And task types presented in the USA textbooks are more diverse. Third, with respect to levels of cognitive demand, in both Korea and the USA textbooks, PNC task and PWC task account most. And compared to the USA, Korea prefer algorithms. In addition, we find out implications for reconstruction of Korea textbook. It is as follows: First, with respect to structures of task and types of proof and reasoning, the diversity of composition needs to be raised. Second, with respect to levels of cognitive demand, the concentration in PNC task needs to be declined. And levels of cognitive demand on types of tasks need to be reconsidered. Third, with respect to tasks' topic and material, internal and external connectivities of mathematics need to be strengthened.

• Science of Emotion and Sensibility
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• v.21 no.4
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• pp.37-42
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• 2018

This study was conducted to evaluate the effects of LED illumination and task difficulty on a person's long-term memory. Illumination levels of 400 lx and 1,000 lx were employed in this study, and task difficulty was set at learning 4 words (easy task) and 7 words (difficult task). The person's retention rate of the learned task was designated as a dependent variable. A total of 64 subjects participated in this study, and 16 participants assigned to each of the four sets of conditions. The results indicated that the retention rate for the difficult task under relatively dark 400 lx conditions was 68.49%, while and the retention rate was higher than 56.03% for 1,000 lx conditions. In addition, for the easy task, the retention rate was 67.97% and 56.55% for the 400 1x and the 1,000 1x conditions, respectively. However, the interaction between illumination and task difficulty was not statistically significant. The study results further suggested that long-term memory can be effective in relatively dark conditions and indirectly suggests that long-term memory may not follow the Yokers-Dodson law.