• International Journal of Fluid Machinery and Systems
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• v.2 no.4
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• pp.315-323
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• 2009

Pressure oscillations triggered by the unstable interaction of dynamic flow features of the hydraulic turbine with the hydraulic plant system - including the electrical design - can at times reach significant levels and could lead to damage of plant components or could reduce component lifetime significantly. Such a problem can arise for overload as well as for part load operation of the turbine. This paper discusses an approach to analyze the overload high pressure oscillation problem using computational fluid dynamic (CFD) modeling of the hydraulic machine combined with a network modeling technique of the hydraulic system. The key factor in this analysis is the determination of the overload vortex rope volume occurring within the turbine under the runner which is acting as an active element in the system. Two different modeling techniques to compute the flow field downstream of the runner will be presented in this paper. As a first approach, single phase flow simulations are used to evaluate the vortex rope volume before moving to more sophisticated modeling which incorporates two phase flow calculations employing cavitation modeling. The influence of these different modeling strategies on the simulated plant behavior will be discussed.

• Journal of the Korean Society of Safety
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• v.28 no.5
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• pp.15-20
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• 2013

This paper dealt with melting characteristics of low-voltage miniature cartridge fuse used for 220 V electronic equipment. The experimental sample is low-voltage miniature cartridge fuse with rating of 250 V(3A) and size of $5{\times}20$ mm. In order to evaluate melting and scattering characteristics of the fuse, we applied to 8/20 ${\mu}s$ surge current, overload current and external thermal stress such as flame of fire. From the experimental results, the fuse element was melted and scattered by applied surge current(above 0.79 kA) and overload current(above 4.5 A). It was also attached to the inner surface of the fuse tube. The fuse element was attached as a thin film on inner surface of fuse tube when large surge current was applied. It was confirmed, however, the fuse element was not changed by external thermal stress such as flame and hot-air.

• The Transactions of the Korea Information Processing Society
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• v.7 no.10
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• pp.3148-3154
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• 2000

In this paper. the design and implementationof the on-line registration system for the school affairs is described. The environments for the system configurations include a PC server under Linux Iperating System. Apache Web-server, and MySQL as database engine. In addition, PHP, which becomes a popular Internet server-based script language lately, is used to implement a real-time database. In order to avoid overload problems during short-term registration period, which deconstraces the typical surge of traffics, the proposed system is designed to minimize the unnecessary interfacing tasks. On administrator side task, the sytem is designed to have environments by separating the dechcated server that restricts the scope of specific database thasks. In doing so, it become possibal to build an optical system by distributing, balancing the transaction load, maintainimg the security and efficient administrative tasks.

• Safety and Health at Work
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• v.5 no.1
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• pp.7-12
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• 2014

Background: In Japan, more than 60% of employees are reported to suffer from anxiety and stress. Consequently, Japanese society has begun to address such important issues as psychogenic disability and job-related suicide. Furthermore, given the aging of society and the surge in the number of elderly people requiring care, it is necessary to adequately and proactively support employees who care for their elderly relatives. The purpose of the present study was to investigate caregiver burden in caring for elderly relatives and work-related stress factors associated with mental health among employees. Methods: We studied 722 men and women aged 18-83 years in a cross-sectional study. The K10 questionnaire was used to examine mental health status. Results: The proportion of participants with a high K10 score was 15% (n = 106). Having little conversation with their supervisor and/or coworkers significantly increased the risk of depression [odds ratio (OR) 1.8], as did high job overload (OR 2.7) and job dissatisfaction (OR 3.8), compared with employees who frequently conversed with their supervisor and/or coworkers. Caring for elderly relatives as a prominent characteristic of an employee was a significant risk factor for depression (OR 2.1). Conclusion: The present study demonstrated that employees who were caring for elderly relatives were significantly associated with an increased risk of depression. To prevent depressive disorders, it may be important to focus on reducing the work-caregiving role conflict, as well as enhancing employees' job control and better rewarding their efforts in the workplace.

• The Journal of the Convergence on Culture Technology
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• v.7 no.2
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• pp.17-25
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• 2021

The recent surge in consumption of traditional liquor related to health, the results of analyzing the chemical characteristics and antioxidant activity by creating Kwaha-ju and Baekhwha-chun, which use Godubab as a method of treating glutinous and normal grains, are as follows. Kwaha-ju is mainly made of glutinous rice, 5.21~12.52% alcohol content, 1.07~2.47g/L in reducing sugar content, 3.22~3.77% pH, Baikhwha-chun alcohol content was 3~5%, except for some experimental groups, and pH was low. As a result of the spectrum analysis of traditional liquor, 50% of the experimental group in Baikhwa-chun is located in the negative area of PC1 such as overload, and some amino acids such as lactic acid, isoleucine, and choline are the main ingredients of glucose, xylose, and maltose. Therefore, the chemical properties and antioxidant activity of Kwaha-ju and Baikhwa-chun, which show similar composition ratio of traditional liquor materials, and use them as basic data to identify and manufacture traditional liquor fermentation through mutual analysis.