• Safety and Health at Work
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• v.10 no.1
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• pp.67-74
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• 2019

Background: Few studies have examined the effects of a forward rotating shift pattern on police employee performance and well-being. This study sought to compare sleep duration, cognitive performance, and vigilance at the start and end of each shift within a three-shift, forward rotating shift pattern, common in United Kingdom police forces. Methods: Twenty-three police employee participants were recruited from North Yorkshire Police (mean age, 43 years). The participants were all working the same, 10-day, forward rotating shift pattern. No other exclusion criteria were stipulated. Sleep data were gathered using both actigraphy and self-reported methods; cognitive performance and vigilance were assessed using a customized test battery, comprising five tests: motor praxis task, visual object learning task, NBACK, digital symbol substitution task, and psychomotor vigilance test. Statistical comparisons were conducted, taking into account the shift type, shift number, and the start and end of each shift worked. Results: Sleep duration was found to be significantly reduced after night shifts. Results showed a significant main effect of shift type in the visual object learning task and NBACK task and also a significant main effect of start/end in the digital symbol substitution task, along with a number of significant interactions. Conclusion: The results of the tests indicated that learning and practice effects may have an effect on results of some of the tests. However, it is also possible that due to the fast rotating nature of the shift pattern, participants did not adjust to any particular shift; hence, their performance in the cognitive and vigilance tests did not suffer significantly as a result of this particular shift pattern.

• Phonetics and Speech Sciences
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• v.7 no.1
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• pp.89-95
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• 2015

We explored Dutch listeners' perception of Korean three-way contrast of fortis, lenis, and aspirated stops. The three Korean stops are all voiceless word-initially, whereas Dutch distinguishes between voiced and voiceless stops, so Korean voiceless stops were expected to be difficult for the Dutch listeners. Among the three Korean stops, fortis stops are phonetically most similar to Dutch voiceless stops, thus they were expected to be the easiest to distinguish for the Dutch listeners. Dutch and Korean listeners carried out a discrimination task using three crucial comparisons, i.e., fortis-lenis, fortis-aspirated, and lenis-aspirated stops. Results showed that discrimination between lenis and aspirated stops was the most difficult among the three comparisons for both Dutch and Korean listeners. As expected, Dutch listeners discriminated fortis from the other stops relatively accurately. It seems likely that Dutch listeners relied heavily on VOT but less on F0 when discriminating between the three Korean stops.

• Journal of Educational Research in Mathematics
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• v.25 no.1
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• pp.21-58
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• 2015

The aim of this study is to look into the didactical background for teaching proportional reasoning in elementary school mathematics and offer suggestions to improve teaching proportional reasoning in the future. In order to attain these purposes, this study extracted and examined key ideas with respect to the didactical background on teaching proportional reasoning through a theoretical consideration regarding various studies on proportional reasoning. Based on such examination, this study compared and analyzed textbooks used in the United States, the United Kingdom, and South Korea. In the light of such theoretical consideration and analytical results, this study provided suggestions for improving teaching proportional reasoning in elementary schools in Korea as follows: giving much weight on proportional reasoning, emphasizing multiplicative comparison and discerning between additive comparison and multiplicative comparison, underlining the ratio concept as an equivalent relation, balancing between comparisons tasks and missing value tasks inclusive of quantitative and qualitative, algebraic and geometrical aspects, emphasizing informal strategies of students before teaching cross-product method, and utilizing informal and pre-formal models actively.

• Steel and Composite Structures
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• v.21 no.6
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• pp.1183-1210
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• 2016

Viscoelastic sandwich structures (VSSs) are widely used in mechanical equipment, but in the service process, they always suffer from aging which affect the whole performance of equipment. Therefore, aging state recognition of VSSs is significant to monitor structural state and ensure the reliability of equipment. However, non-stationary vibration response signals and weak state change characteristics make this task challenging. This paper proposes a novel method for this task based on adaptive second generation wavelet packet transform (ASGWPT) and multiwavelet support vector machine (MWSVM). For obtaining sensitive feature parameters to different structural aging states, the ASGWPT, its wavelet function can adaptively match the frequency spectrum characteristics of inspected vibration response signal, is developed to process the vibration response signals for energy feature extraction. With the aim to improve the classification performance of SVM, based on the kernel method of SVM and multiwavelet theory, multiwavelet kernel functions are constructed, and then MWSVM is developed to classify the different aging states. In order to demonstrate the effectiveness of the proposed method, different aging states of a VSS are created through the hot oxygen accelerated aging of viscoelastic material. The application results show that the proposed method can accurately and automatically recognize the different structural aging states and act as a promising approach to aging state recognition of VSSs. Furthermore, the capability of ASGWPT in processing the vibration response signals for feature extraction is validated by the comparisons with conventional second generation wavelet packet transform, and the performance of MWSVM in classifying the structural aging states is validated by the comparisons with traditional wavelet support vector machine.

• Science of Emotion and Sensibility
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• v.20 no.1
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• pp.115-132
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• 2017

Differences in reaction time and accuracy were compared among driver groups of middle-, old-, and stroke old-age drivers using various reaction time tasks including simple reaction task, 2-choice task, 4-choice task with different stimuli eccentricity, search task, and moving target detection task. The results can be summarized as followings. First, although overall reaction time tended to be slowed with age and stroke, stroke old drivers showed significantly slower reaction time than the other driver groups when the stimuli were presented in a large eccentricity. Second, differences in reaction time for 2-choice task and moving target detection task seemed to be determined mainly by participants' simple reaction time. Third, the search task which required temporary retention of previously presented stimuli was found to be more sensitive in discriminating difference in reaction time between middle-age drivers and old-age drivers (including stroke old drivers). Fourth, reaction accuracy of old (and stroke old) drivers decreased when more stimuli alternatives were presented and temporary retention for stimuli was required. Altogether, memory demand in reaction time task can be sensitive to evaluate performance for different age groups, whereas size of useful field of view for brain stroke.

• Physical Therapy Rehabilitation Science
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• v.3 no.2
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• pp.134-141
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• 2014

Objective: The purpose of this study was to compare with different distance across three conditions in stroke survivors with the grading of cognitive state. Design: Cross-sectional study. Methods: Twelve stroke patients who agreed to active participation were included. Participants were allotted to normal cognitive (CN) group (n=7) and cognitive impairment (CI) group (n=5) and then walked on a self-paced walkway at three conditions on the Time Up and Go (TUG) test and the 6 minute walk test (6MWT): 1) walking with your comfortable speed, 2) walking while carrying a tray with glasses, 3) walking with a verbal cognitive task. The TUG test was repeated three successful times on each condition. For the 6MWT, participants were tested one time. Results: The CI group walked slower than the CN group at the three conditions on the TUG test. However, there was no significant difference between two groups to each condition. A significant effect of dual tasking was found only in error of verbal cognitive task condition for the TUG test (p<0.05). On the 6MWT, the participants in the CI group walked short distance rather than the CN group (p<0.05). There were significant differences between two groups not only at all conditions but also at error of verbal cognitive task condition as well (p<0.05). Conclusions: To consider the results of different distances such as the TUG test and the 6MWT, we think that exercises in long distance would be more effective to patients with CI. Those would be improved patient's endurance in cognitive problem.

• Journal of the Korean Society of Physical Medicine
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• v.18 no.4
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• pp.133-144
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• 2023

PURPOSE: This study aimed to determine the effects of task-oriented treadmill training on the gait and balance ability and functional activity in 20 patients with subacute stroke. METHODS: The study subjects were twenty stroke patients, ten randomly placed in the experimental group and ten in the control group. Both the experimental and control groups received 30 minutes of traditional physical therapy and an additional 15 minutes of functional electrical stimulation therapy. The experimental group was given task-oriented treadmill training, while the control group received general treadmill training. Each session lasted for 25 minutes, three times a week, over four weeks, totaling 12 sessions. RESULTS: Both groups showed statistically significant differences in the 10-metre walk test (10MWT), timed up and go test (TUG), Fugl-Meyer Assessment (FMA), and Modified Barthel index (MBI). However, statistically significant differences in the Functional Ambulation Categories (FAC) and Berg Balance Scale (BBS) were seen only in the experimental group. There were statistically significant differences in the between-group differences value comparisons in the 10MWT, BBS, TUG, FMA, and MBI. CONCLUSION: Task-oriented treadmill training positively impacts gait, balance, and daily function in subacute stroke patients. This study highlights the benefits of training on unstable surfaces and offers valuable insights for stroke rehabilitation and gait training.

• The Journal of Korean Physical Therapy
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• v.32 no.5
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• pp.302-306
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• 2020

Purpose: The purpose of this study was to investigate comparisons of vastus medialis (VMO) and vastus lateralis (VL) muscle activities according to different heights during drop landing in flatfooted adults. Methods: Fifteen subjects with a flat foot arch and 15 subjects with a normal feet arch were participated. Subjects performed a double limb drop landing task from 20, 40, and 60 cm heights. Surface electromyography was used to measure the muscle activities of the VMO and VL during drop landing. Results: There were significant differences of muscle activities in the VMO, VL, and the VMO and VL ratio between groups. The electromyography values of VMO, VL, and the VMO and VL ratio in the normal group were significantly greater than in the flat foot group, and muscle activities and the VMO and VL ratio significantly increased with landing heights in the both groups. Conclusion: Our results indicated that muscle activity patterns of VOM and VL in the flat foot group were lower at heights than in the normal group, so calf tightness was negative effects on balance and gait ability, so assessment of muscle activation patterns in the knee extensors should be considered during exercise and treatment of flat feet.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.11 no.6
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• pp.27-37
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• 2016

Startup teams should be prompt to seize an business opportunity and handle various business problems with which they has not been faced before. This research examines and compares the hypotheses about the processes of communication media usage, knowledge sharing and team agility by the level of task conflict. In order for detailed investigation, each of antecedent was divided into sub-dimensions: communication media usage into synchronous and asynchronous media usage, and knowledge sharing into speed and quantity of knowledge sharing. Team agility, the dependent variable, was proposed as an important success factor of startup teams. The research model describes that the communication media usage affects knowledge sharing and consequently team agility. The differences of media usage and relationships among variables were proposed as the level of task conflict in teams. 230 data points were collected from startup teams under 5 years and statistically processed to test research model and hypotheses. From the total sample analysis, the results indicate that the knowledge sharing speed is positively associated with the quantity, and the knowledge sharing speed and quantity have positive associations with team agility. Both synchronous and asynchronous communication media usage also has significant positive associations with knowledge sharing speed. On the other hand, media usage did not show significant direct association with knowledge sharing quantity. From the group comparisons of task conflict, it was found that the higher task conflict, the higher in media usage, knowledge sharing speed and quantity, and team agility. The process of media usage, knowledge sharing, and team agility were found to be different between the high and low task conflict. From these results, the authors discussed and proposed some implications for startup team leaders.

• Journal of Elementary Mathematics Education in Korea
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• v.19 no.4
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• pp.457-484
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• 2015

This study aims to investigate an approach to teach proportional reasoning in elementary mathematics class by analyzing the proportional strategies the students use to solve the proportional reasoning tasks and their percentages of correct answers. For this research 174 sixth graders are examined. The instrument test consists of various questions types in reference to the previous study; the proportional reasoning tasks are divided into algebraic-geometric, quantitative-qualitative and missing value-comparisons tasks. Comparing the percentages of correct answers according to the task types, the algebraic tasks are higher than the geometric tasks, quantitative tasks are higher than the qualitative tasks, and missing value tasks are higher than the comparisons tasks. As to the strategies that students employed, the percentage of using the informal strategy such as factor strategy and unit rate strategy is relatively higher than that of using the formal strategy, even after learning the cross product strategy. As an insightful approach for teaching proportional reasoning, based on the study results, it is suggested to teach the informal strategy explicitly instead of the informal strategy, reinforce the qualitative reasoning while combining the qualitative with the quantitative reasoning, and balance the various task types in the mathematics classroom.