• Safety and Health at Work
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• v.12 no.1
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• pp.102-107
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• 2021

Background: This study was conducted to identify the association between sleep duration and suicidal ideation among farmers in Korea. Methods: We used Safety for Agricultural Injuries of Farmers cohort data collected from September 2015 to June 2018, which was an agricultural survey on the health and behaviors of adult farmers in Jeju island, Korea. Results: A total of 964 participants were included in the analysis, and 3.7% of them were identified with having suicidal ideation. The frequencies of average daily sleep duration of <6 h (short sleep), 6-8 h (normal sleep), and >8 h (long sleep) were 24.4%, 70%, and 5.6%, respectively. Multivariate analyses revealed that short sleep duration was significantly associated with suicidal ideation compared with normal sleep duration (odds ratio = 2.49, 95% confidence interval = 1.07-5.77). Conclusion: Our findings suggest that short sleep duration in farmers result in higher suicidal ideation. Because individuals who have suicidal ideation often commit suicide, careful monitoring is required to prevent suicide in farmers with short sleep duration.

• Journal of the Korea Institute of Building Construction
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• v.11 no.1
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• pp.73-81
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• 2011

The ultimate goal of construction is to complete the given work in the most economical and safest way within the required construction period while meeting the quality standards specified in the design drawing. There are a few characteristics of finish work. First, executed in subdivided processes, finish work involves a very diverse and complex structure. Second, there are no criteria for each segmented process with regard to the appropriate time of input. Third, it is not very necessary to set priorities for lead and lag works. This study intends to provide information on the completion of a project in accordance with the required duration by setting priorities in the delay of each detailed process of finish work to minimize delay in finish work. In this study, finish work is divided into wet work and other types of finish work, and the importance of each process is classified based on the given details of each process. In addition, the study employs a survey to analyze delay factors of a designer, a constructor, and a supplier. Using the survey results, the study sets priorities in delay of final work to provide information on the completion of an apartment project within the planned construction period.

• Journal of Preventive Medicine and Public Health
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• v.28 no.3 s.51
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• pp.715-725
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• 1995

This study was done for identifying the factors which affect psychologic symptoms of low back(LBP) patients. The study subjects were 43 work-related low back pain patients, 28 work-related non-low back pain patients and 47 general low back injury patients. The study materialis SCL 90-R for checking psychologic symptoms and questionnaire for obtaining general information about the subjects. The data were analyzed by model of analysis of covariance adjusted by several variables such as gender, age, education and marital status and then compared the least square means of symptom score between groups. To identify the factors that affect psychologic symptom, duration of suspension, return to work and interaction factor of these two variables were analyzed by multivariate model and we calcuated partial correlation coefficient of these variables. As a result, work-related LBP patients showed higher score of symptoms in somatization, depression and psychosis than work-related non-LBP and non-work-related LBP. Duration of suspension and return to work were significant explanatory variables for psychologic symptom score of work-related LBP. Then, we may conclude that the treatment and rehabilitation programe for work-related LBP should cover the strategy of early return to work.

• Safety and Health at Work
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• v.7 no.4
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• pp.363-371
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• 2016

Background: Seafaring is an inherently stressful environment. Because working time and leisure time is spent in the same confined environment for a prolonged period of time, many stressors present in seafaring can also be conceived of as chronic. We explored the effects of duration at sea, seafaring experience, environmental stressors, and psychological capital (PsyCap) on the sleep quality and fatigue of seafarers. PsyCap is a construct that draws upon ideas from positive psychology and positive organizational behavior, and is intended to capture an individual's psychological capacities that can be developed and utilized for performance improvements. Methods: We collected survey data from a sample of seafarers working in the offshore re-supply industry (n = 402) and a sample of seafarers working on board combined passenger and cargo ships (n = 340). Results: PsyCap emerged as a robust predictor with statistically significant relations to fatigue and sleep quality in both samples. PsyCap also interacted with duration at sea in explaining fatigue in seafarers working on board the passenger and cargo ships. Seafarers on passenger and cargo ships also reported significantly higher levels of fatigue than those working in the offshore re-supply industry. Conclusion: Coupled with emerging research showing that PsyCap is trainable, our results suggest that maritime organizations could have much to gain by being cognizant of and developing routines for continually developing the PsyCap of their employees.

• Journal of the Korea Institute of Building Construction
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• v.15 no.6
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• pp.653-660
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• 2015

Technologies for reducing construction duration are key factors in nuclear power plant construction projects, as a reduction in construction duration at the construction phase leads to a reduction in construction cost and an increase in profits through the early operation of the nuclear power plant. To analyze the constructability of the height of single-layer placement of formwork for the Reactor Containment Building (RCB) exterior wall through lateral pressure according to the height of concrete placement, the deformation criteria for formwork, and a new form design, 'MIDAS GEN (hereinafter referred to as MIDAS)' is used in this study. The cost and workload of formwork are derived according to the unit of height of the RCB exterior wall. Based on the result, it was found that the higher the RCB exterior wall, the higher the material cost, and the less the construction duration and the less the total number of formwork layers. Based on this result, it is believed that the material cost and the construction duration can be appropriately determined according to the formwork height.

• Journal of Korean Society of Transportation
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• v.9 no.2
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• pp.101-120
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• 1991

The Subject of this research work is to study the driver's vision and eye-movement ch-aracteristics under the diffrent condiction of road traffic and driving. The analysis of this investigation was conducted spatially or temporaly into three parts'eye-mark distribution, viewing-time percentage and fixation duration. This dissertation focuses on analysis of dr-iver's visual characteristics to improve road circumstamces. In this study driver's ch-aracteristics are measured with eye-mark recorder and analyzed statistically The main features of this study are : 1st Duration distribution of fixation point is significant in 87% at 5% of the significant level in Gamma Distribution. The average of fixation duration by road are 0.33sec on streets 0.45sec on Roads and 0.86sec on highways. The average of fixation duration by visual objects are 0.4sec on road surface 0.26sec on road shoulder 0.49sec on traffic sign 0.37sec on warning sign and 0.67sex on gwide sign. 2st Moving anglrs of a fixation point are fit in the Exponential Distribution. The average moving angle is appeared to be 3.85。 on streets 2.81。 on roads 2.73。 on highway and 5 。 on intersecyion. 3st As a result of examining alignment of guide and warning sign in traffic signs cxisting foundation methods are less affected by lane than by apeed of a vehicle.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10b
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• pp.212-217
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• 1993

In this paper, characteristics of the motions of a human arm are investigated experimentally. When the conditions of the target point are restricted, human adjusts its trajectory and velocity pattern of the arm to fit the conditions skillfully. The purpose of this work is to examine the characteristics of the trajectory, velocity pattern, and the size of the duration in the following cases. First, we examine the case of point-to-point motion. The results are consistent with the minimum jerk theory. However, individual differences in the length of the duration can be observed in the experiment. Second, we examine the case which requires accuracy of positioning at the target point. It is found that the velocity pattern differs from the bell shaped pattern explained by the minimum jerk theory, and has its peak in the first half of the duration. When higher accuracy of the positioning is required, learning effects can be observed. Finally, to examine the case which requires constraint of the arm posture at the target point, we conduct experiments of a human trying to grasp a cup. It is considered that this motion consists of two steps : one is the positioning motion of the person in order to start the grasping motion, the other is the grasping motion of the human's hand approaching toward the cup and grasping it. In addition, two representative velocity patterns are observed : one is the similar velocity pattern explained in the above experiment, the other is the velocity pattern which has its relative maximum in the latter half of the duration.

• Journal of Korean Society of Water and Wastewater
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• v.19 no.5
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• pp.619-624
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• 2005

This work is for examining a simplified equation based on the rational formula, which can easily decide storm-water detention volume in small urban catchments. The storm-water detention volume is determined by the inflow hydrograph flowing to detention basin and the outflow hydrograph discharged from the detention basin. The ratio of average outflow over the period of rainfall duration against allowable discharge was 0.5 in former simplified equation. But this research has found that the average outflow ratio depends on the storage methodology. In the case of the on-line storage method, the average outflow ratio is a function of the time of concentration of the catchments and rainfall duration, which ranged from 0.5~1.0. In the case of the off-line storage method, the average ratio is a function of peak discharge and allowable discharge except above time of concentration and rainfall duration, where its function value ranged from 1.0~2.0. When applying this equation to small catchment in Mokpo city, South Korea, we could easily calculate the relation curve between the storm-water detention volume and allowable discharge.

• Journal of Families and Better Life
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• v.23 no.1 s.73
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• pp.223-239
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• 2005

The purpose of this study is to explore the impacts of personality variables, family variables, job variables, work-family conflict and job satisfaction on life satisfaction of family business workers. The major findings are as follows: 1. There was direct causal effects of job satisfaction, Sunday working level, the duration of the family business, an academic background on life satisfaction of family business workers. 2. Such variables family variables(family size, number of family workers, number of unpaid family workers), working time variables (working hours per a day, saturday working level, flexibility of working time), work-family conflict had indirect causal effects on life satisfaction of family business workers

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.3 no.1
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• pp.17-27
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• 1997

The PT program provides relief to most patients with symptom of TOS. So the purpose of our study is to evaluate a effects of PT program in patients with TOS. PT program included orthopaedic manual therapy with the aim of restoring the function of the upper thoracic aperture is to be recommended, and long-term following is advisable. 1. Mean treatment duration was over an 11.4 day(range 4~24). 2. At the follow-up evaluation, 88.1% of the patients were satisfied with the effects of their therapy. 3. 73% of the patients returened to work after PT and 88% of the patients carried through the recommendations given at discharge during follow up. 4. Normalized grip strength and Tinel' sign predicted patient satisfaction(p< .001) and return to work(p< .001). 5. Return to work was more often successful if the work was sedentary rather than heavy (p< .05).