• Journal of the Ergonomics Society of Korea
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• v.31 no.2
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• pp.371-377
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• 2012

Objective: The aim of this study is to investigate effect of driver's cognitive distraction on driver's physiological state and driving performance, and then to determine parameters appropriate for detecting the cognitive distraction. Background: Driver distraction is a major cause of traffic accidents and poses a serious threat to traffic safety due to ever increasing use of in-vehicle information systems and mobile phones during driving. Cognitive distraction, among four different types of distractions, prevents a driver from processing traffic information correctly and adapting to change in surround vehicle behavior in time. However, the cognitive distraction is more difficult to detect because it normally does not involve significant change in driver behavior. Method: A full-scale driving simulator was used to create virtual driving environment and situations. Participants in the experiment drove the driving simulator in three different conditions: attentive driving with no secondary task, driving and conducting secondary task of adding numbers, and driving and conducting secondary task of conversing with an experimenter. Parameters related with driver's physiological state and driving performance were measured and analyzed for their change. Results: The experiment results show that driver's cognitive distraction, induced by secondary task of addition and conversation during driving, increased driver's cognitive workload, and indeed brought change in driver's physiological state and degraded driving performance. Conclusion: The galvanic skin response, pupil size, steering reversal rate, and driver reaction time are shown to be statistically significant for detecting cognitive distraction. The appropriate combination of these parameters will be used to detect the cognitive distraction and estimate risk of traffic accidents in real-time for a driver distraction warning system.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.11 no.2
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• pp.101-111
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• 2016

Startup has lot of limitation such as time and budget shortage, and few human resources, and may be under the very stressful condition. Naturally in these context, there is always conflict among the startup team members, but the impact of conflict on teamwork or team performance has not been empirically tested. This study examines the relationship among the conflict, teamwork and team performance in startup context. Different two types of conflict and four factors of teamwork for team performance are identified from a literature review and tested; task conflict and relationship conflict as antecedents, teamwork was composed of communication, collaboration, coordination and cohesion, leading to team performance. 142 data points were collected from startup representatives to test these hypotheses. PLS data analysis indicated that the task conflict positively effects on all teamwork factors, but relationship conflict has statistically significant effect on only two teamwork factors, collaboration and coordination in negative relationship. Teamwork factors effects on team performance except communication. Based on the results, we proposed practically several team management skills for startup managers, leaders and even members, and explained theoretical contributions.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.1
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• pp.18-26
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• 2009

Recently, from an environmental conservative point of view, the need of high-efficiency lighting system, using LED(Light Emitting Diode) light sources have been increased. However, applied LED light sources without regard to its color and pattern provide visual discomfort to occupant. The objective of this study is not only to evaluate the performance of task work under different correlated color temperature condition, but also furnish the preliminary data as concerning its purpose and user of inner space. For the purpose of this study, two types of LED light sources and a fluorescent light source were selected. Thirty undergraduate students served as the participants. Two different task work sheets were conducted to evaluate the accuracy and duration of time. Results from subjective performance, task work of error modification showed that LED light sources were 2.5[%] higher in accuracy with 17.1[%] lower duration than a fluorescent light source. In the case of reading task work, It is presented 20.6[%] decrease with the LED light sources comparison with a fluorescent light source.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.2
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• pp.835-838
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• 2016

Background: Lung cancer remains one of the most common cancers in the world, both in terms of new cases (about 13% of total per year) and deaths (nearly one cancer death in five), because of the high case fatality. Errors in lung cancer type or malignant growth determination lead to degraded treatment efficacy, because anticancer strategy depends on tumor morphology. Materials and Methods: We have made an attempt to evaluate effectiveness of machine learning algorithms in the task of lung cancer classification based on gene expression levels. We processed four publicly available data sets. The Dana-Farber Cancer Institute data set contains 203 samples and the task was to classify four cancer types and sound tissue samples. With the University of Michigan data set of 96 samples, the task was to execute a binary classification of adenocarcinoma and non-neoplastic tissues. The University of Toronto data set contains 39 samples and the task was to detect recurrence, while with the Brigham and Women's Hospital data set of 181 samples it was to make a binary classification of malignant pleural mesothelioma and adenocarcinoma. We used the k-nearest neighbor algorithm (k=1, k=5, k=10), naive Bayes classifier with assumption of both a normal distribution of attributes and a distribution through histograms, support vector machine and C4.5 decision tree. Effectiveness of machine learning algorithms was evaluated with the Matthews correlation coefficient. Results: The support vector machine method showed best results among data sets from the Dana-Farber Cancer Institute and Brigham and Women's Hospital. All algorithms with the exception of the C4.5 decision tree showed maximum potential effectiveness in the University of Michigan data set. However, the C4.5 decision tree showed best results for the University of Toronto data set. Conclusions: Machine learning algorithms can be used for lung cancer morphology classification and similar tasks based on gene expression level evaluation.

• Journal of the Korea Society for Simulation
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• v.27 no.2
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• pp.71-81
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• 2018

Forklifts in a shipyard lift and transport heavy objects. Tasks occur dynamically and the rate of the task occurrence changes over time. Especially, the rate of the task occurrence is high immediately after morning and afternoon business hours. The weight of objects varies according to task characteristic, and a forklift also has the workable or allowable weight limit. In this study, we propose an online forklift dispatching algorithm based on nearest-neighbor dispatching rule using minimal cost assignment approach in order to attain the efficient operations. The proposed algorithm considers various types of forklift and multiple jobs at the same time to determine the dispatch plan. We generate dummy forklifts and dummy tasks to handle unbalance in the numbers of forklifts and tasks by taking their capacity limits and weights. In addition, a method of systematic forklift selection is also devised considering the condition of the forklift. The performance indicator is the total travel distance and the average task waiting time. We validate our approach against the priority rule-based method of the previous study by discrete-event simulation.

• Safety and Health at Work
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• v.11 no.3
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• pp.335-346
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• 2020

Background: Nursing service is a nonroutine work with an excessive physical load and diverse tasks. This study derived representative common tasks based on the frequently occurring tasks with a high physical load in the nursing workers' daily work and developed indicators to evaluate the work risk by reflecting the characteristics of nonroutine work. Methods: Common tasks were classified through the following stages: literature review, first focus group interview (FGI) with experts, first classification of common tasks, second FGI with hospital health managers, a survey of nursing service workers, and the final classification of common tasks for each task type. To develop an objective risk index for physical load assessment, we investigated the frequency and duration of the derived common tasks via survey. Results: Nursing common tasks were categorized into six task types and 56 subtasks. To evaluate the risks of various tasks in nonroutine works, three frequencies and three working time levels were defined by examining the task frequency and working hours. Exposure time was defined to reflect the characteristics of a nonroutine job. The final risk assessment was the product of the exposure time level and job intensity level. From this, four risk action levels were derived. Conclusion: This study has the advantage of solving the problem of focusing on some tasks in evaluating the physical load. It was meaningful in that a new risk assessment index based on exposure time was proposed based on the development of an evaluation scale for frequency and time by reflecting the characteristics of nonroutine work.

• Physical Therapy Korea
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• v.23 no.4
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• pp.16-26
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• 2016

Background: Deficiencies in the ability to maintain balance are common in elderly. Augmented feedback such as knowledge of results (KR) can accelerate learning and mastering a motor skill in older people. Objects: We designed this study to examine whether one session of Wii-Fit game with self-regulated KR is effective for elderly people, and to compare the effect of two different timings of self-regulated KR conditions. Methods: Thirty-nine community-dwelling elders, not living in hospice care or a nursing home, participated in this study. During acquisition, two groups of volunteers were trained in 10 blocks of a dynamic balancing task under the following 2 conditions, respectively: (a) a pre-trial self-regulated KR ($n_1=18$), or (b) a post-trial self-regulated KR ($n_2=21$). Immediate retention tests and delayed retention tests of balancing performance were administered in 15 minutes and 24 hours following acquisition period, respectively. Results: In both groups, significant improvements of balancing performances scores were observed during the acquisition period. Regardless of the group, mean of balancing performance scores on retention tests were well-maintained from the final session. There were no significant differences between groups in balancing performance scores during the acquisition period (p>.05); however, the post-trial self-regulated KR group exhibited significantly higher balancing performance scores in both the immediate retention test and delayed retention test than that of the pre-trial self-regulated KR group (p<.05). Conclusion: Therefore, subjects who regulated their feedback after a dynamic balancing task, during the acquisition period, experienced more efficient motor learning during the retention period than did subjects who regulated their feedback before a dynamic balancing task. Accordingly, in case of presenting the KR of motor learning in clinical settings to elders who reduced dynamic balance abilities, the requesting time of KR is imperative according to self-estimation processes as well as types of KR and practice.

• The Journal of Korean Physical Therapy
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• v.21 no.1
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• pp.65-71
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• 2009

Purpose: Numerous investigators demonstrated that adaptative changes were induced by motor skill acquisition in the central nervous system. We investigated the changes of neuroelectric potential following motor learning with serial reaction time task in young healthy subjects, using electroencephalography (EEG). Methods: Twelve right-handed normal volunteers were recruited, who have no history of neurological dysfunction and were given to written the informed consent. All subjects were assigned to flex to extend the wrist joint or flex the thumb for pressing the matched button as quickly and accurately as possible, when one of five colored lights was displayed on computer screen (red, yellow, green, blue, white). EEG was measured, whenfive types simulations ware presented randomly with equal probabilities of 20% in total 200 times at the pre and post test. And they were scheduled for 30 minutes practice session during two consecutive days in the laboratory. Results: The results showed that the reaction time at the post test was significantly reduced, compared to one of the pre test in serial reaction time task. In EEG map analysis, the broaden bilateral activation tended to be changed to the focused contralateral activation in the frontoparietal area. Conclusion: These findings showed that acquisition of motor skill led to product more fast motor execution, and that motor learning could change cortical activation pattern, from the broaden bilateral activation to the focused contralateral activation. Thus we concluded that the adaptative change was induced by motor learning in healthy subjects.

• Korean Journal of Community Nutrition
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• v.2 no.4
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• pp.593-604
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• 1997

The job characteristics and competencies of 285 dietitians in employee foodservices were investigated by worker-oriented job analysis methodology. The purposes of this study were to : a) determine the knowledge, abilities, skills and other characteristics(KASO, hereafter) needed for dietitians in two types of employee foodservice groups(self-operated vs. contracted) and b) the analysis of the degree of frequency and importance and entry requirements of KASO items listed below : their degree of frequency, the level of importance and their function as entry requirements. The 134 KASO items would be divided into 12 task categories. The questionnaire was mailed to 250 dietitians who are members of The Korean Dietetic Association Practice Group in self-operated foodservices(hereafter group A) and 250 dietitians who are employed in contracted foodservice companies(hereafter group B). Completed questionnaires were received from 285 dietitians(121 in self-operated, 164 in contracted) ; with a response rate of 57%. Statistical data analysis was completed using the SPSS/win and the SAS/win packages. The results of this study can be summarized as follows. 1) Analysis of the degree of frequency, importance and entry requirements of 134 KASO items in group A showed a high priority(score〉4.0) placed on 14 items in relation to dietetic tasks and 9 items in relation to human attributes, whereas in group B 19 items in relation to dietetic tasks and 11 items in relation to human attributes. 2) Comparing responses about the KASO items in the 12 task categories, there was a significant difference between the two sample groups with regard to degree of frequency : group A scored 3.29, group B scored 3.50(p〈0.01). With regard to importance of KASO items in 12 task categories, group A scored 3.78 and group B scored 3.88 showing no significant differences. With to entry requirements of KASO items in 12 task categories, group A scored 3.29 and group B scored 3.46 showing a significant difference(p〈0.05). (Korean J Community Nutrition 2(4) : 593-604, 1997)

• Journal of the Korean Dietetic Association
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• v.21 no.1
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• pp.37-56
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• 2015

This study was conducted to develop job standards for clinical dietitian administering clinical nutrition therapy to diabetic patients in hospitals. Based on DACUM (Developing A Curriculum) analysis of 17 members including clinical dietitians, professors majoring in clinical nutrition and researchers, information on duties, tasks and task elements of clinical dietitians for diabetes care were derived and applied to diabetes mellitus-specific clinical nutrition care in hospitals for evaluation. The final developed job standards for clinical dietitians for diabetes care included four duties, 19 tasks and 56 task elements. The duties consisted of nutrition assessment, nutrition diagnosis, nutrition intervention, and nutrition monitoring evaluation. For application of diabetes mellitus-specific job standards in clinical nutrition care, 108 work activities were developed and classified into 90 basic and 18 recommended types. Performance rates of standardized jobs were 80.2% at nutrition assessment, 99.6% at nutrition diagnosis, 78.5% at nutrition intervention, and 32.9% at nutrition monitoring evaluation. These results can be applied as guidelines to implement jobs for diabetes mellitus-specific clinical nutrition services in clinical settings. In addition, they would be useful for education standards in educational institutions for education and training of clinical dietitian.