• Journal of the Korean Society of Industry Convergence
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• v.26 no.5
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• pp.765-774
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• 2023

The Ministry of Employment and Labor implemented the process safety management(PSM) system from 1996 to prevent major industrial accidents caused by chemical substances, but the number of accidents did not drastically decrease. Even in workplaces with excellent PSM ratings, large-scale chemical accidents still occur due to non-compliance with safety work procedures and insufficient safety measures during maintenance and other work. Accordingly, the chemical accident risk warning system was introduced in 2014 to supplement the PSM system and prevent accidents that may occur during regular or unexpected maintenance and repair work. In the meantime, changes in the safety management system have been checked since the introduction of the chemical accident risk warning system at chemical handling workplaces, and based on the results, a plan for upgrading this system has been proposed. The effect of the CARW system was found to directly prevent accidents through wired and on-site consulting and post-management at the workplace and indirectly contribute to the establishment of a safety and health management system at the workplace, such as improving safety culture awareness.

• The Journal of the Korea Contents Association
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• v.7 no.12
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• pp.199-208
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• 2007

The Employment instability of current employees should be related to uncertainty of switching job for experienced ones. Therefore, the researcher would like to look into the influence which is taken by Job Insecurity after verifying Job Instability Recognition through employees and identification of the level into Trust in organization, In particular, for the employee who is working in a catering department and expected to be ranked highly among tourist companies concerning Job Instability Recognition. According to the result of a tentative theory that Job Insecurity will effect negatively to Trust, conversely, it does not give any considerable effects both Trust in colleague and company. It just turned out that the risky factor of their dismissal could come to a substantial consequence to Trust in Superior. In this regard, a study shows that there isn't any relation to Trust in colleague even though there Is the cause of being fired. In this sense, employees can assume that a work evaluation or relationship with their superior, who work together in the field, is related to the risky factor regarding their dismissal. In other words, it turned out that there was no difference between regular employee and non-regular employee in the matter of Job-Instability-Recognition.

• Journal of Digital Convergence
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• v.18 no.8
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• pp.263-270
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• 2020

This study was conducted to identify the effects of major selection motivation and occupational values on employment preparation behavior for paramedic students', and to provide basic data for improving employment preparation behavior based on the results. After receiving the consent to participate in the research from November 4 to 8, 2019, a self-written questionnaire was conducted for 3rd and 4 year university paramedic students' located in D Metropolitan City and J Province. Among the collected data, 341 parts, except for the 9 parts with insufficient response, were finally analyzed with SPSS ver. 12.0 (Window). Results, personal motivation of major selection motivation, intrinsic work values of occupational values, and extrinsic work values were influenced in order to employment preparation behavior.Therefore, it is considered that it is necessary to open a vocational value course in individual and group counseling and regular or non-regular curriculum considering the characteristics of gender and grade, major selection motivation, and occupational oalues.

• Journal of Engineering Education Research
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• v.14 no.4
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• pp.62-68
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• 2011

Many engineering schools in Korea implement ABEEK programs. One of the core parts of ABEEK is accreditation criterion 2, the program outcomes and their appraisal. This paper tries to discuss the program outcomes and to study the impact of applying the program outcomes to one of the graduation requirements. We show simple survey results for implementing ABEEK programs concerning the program outcomes and their relation to graduation requirements. If the program outcomes are used as one of the graduation requirements, some graduates may satisfy the average grade point for graduation requirements but can not meet the program outcome criteria satisfied by other than regular classes. In this case, the graduate may have trouble to try to meet the program outcome criteria, since he may not be able to stay in school without taking classes. The problems of setting the levels of program outcomes as graduation requirements, non classwork related program outcomes, and work burden to professors should be also prudently reviewed for successful ABEEK implementation.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.869-872
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• 2000

The aim of present work was to fabricate the piezoelectric composite materials of low megahertz applications such as non-destructive testing of materials. Among all the various composites, those with PZT rods embedded in Spurrs epoxy with regular periodicity (1-3 connectivity) was fabricated by dice and fill method. The fabricated size of the PZT cell were 0.18X0.18, 0.28X0.28mm$^2$, respectively. And the volume ratio of the PZT cell were 52, 64%, respectively. The resonant frequency and anti-resonant frequency of the composites were 3.5 MHz and 4.3MHz, respectively. The piezoelectric coupling coefficient were about 38 and 37% and the mechanical quality factor were about 12.7 and 22. These value were very different from these of bulk PZT Plate.

• Kyungpook Mathematical Journal
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• v.59 no.3
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• pp.563-589
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• 2019

Let W and V be manifolds of dimension m + 2, M a locally flat submanifold of V whose dimension is m. Let $f:W{\rightarrow}V$ be a homotopy equivalence. The problem we study in this paper is the following: When is f homotopic to another homotopy equivalence $g:W{\rightarrow}V$ such that g is transverse regular along M and such that $g{\mid}g^{-1}(M):g^{-1}(M){\rightarrow}M$ is a simple homotopy equivalence? $L{\acute{o}}pez$ de Medrano (1970) called this problem the weak h-regularity problem. We solve this problem applying the codimension two surgery theory developed by the author (1973). We will work in higher dimensions, assuming that $$m{\geq_-}5$$.

• Ocean Systems Engineering
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• v.2 no.4
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• pp.239-255
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• 2012

Analysis of ship parametric roll has generally been restricted to simple analytical models and sophisticated time domain simulations. Simple analytical models do not capture all the critical dynamics while time-domain simulations are often time consuming to implement. The model presented in this paper captures the essential dynamics of the system without over simplification. This work incorporates various important aspects of the system and assesses the significance of including or ignoring these aspects. Special consideration is given to the fact that a hull form asymmetric about the design waterline would not lead to a perfectly harmonic variation in metacentric height. Many of the previous works on parametric roll make the assumption of linearized and harmonic behaviour of the time-varying restoring arm or metacentric height. This assumption enables modelling the roll motion as a Mathieu equation. This paper provides a critical assessment of this assumption and suggests modelling the roll motion as a Hills equation. Also the effects of non-linear damping are included to evaluate its effect on the bounded parametric roll amplitude in a simplified manner.

• Journal of applied mathematics & informatics
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• v.41 no.6
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• pp.1155-1171
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• 2023

This paper investigates a non Markovian M/G/1 queue with retrial policy, different kind of service rates as well as unsatisfied clients which is inspired by an example of a transmission medium access control in wireless communications. The server tends to work continuously until it finds at least one client in the system. The server will begin its maintenance tasks after serving all of the clients and if the system becomes empty. Provisioning periods in regular working periods and maintenance service periods should be evenly divided. Using supplementary variable technique, the amount of clients in the system as well as in the orbit were found. Further few performance measures of the system were demonstrated numerically.

• Safety and Health at Work
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• v.2 no.1
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• pp.39-51
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• 2011

Objectives: This study was designed to evaluate exposure levels of various chemicals used in wafer fabrication product lines in the semiconductor industry where work-related leukemia has occurred. Methods: The research focused on 9 representative wafer fabrication bays among a total of 25 bays in a semiconductor product line. We monitored the chemical substances categorized as human carcinogens with respect to leukemia as well as harmful chemicals used in the bays and substances with hematologic and reproductive toxicities to evaluate the overall health effect for semiconductor industry workers. With respect to monitoring, active and passive sampling techniques were introduced. Eight-hour long-term and 15-minute short-term sampling was conducted for the area as well as on personal samples. Results: The results of the measurements for each substance showed that benzene, toluene, xylene, n-butyl acetate, 2-methoxy-ethanol, 2-heptanone, ethylene glycol, sulfuric acid, and phosphoric acid were non-detectable (ND) in all samples. Arsine was either "ND" or it existed only in trace form in the bay air. The maximum exposure concentration of fluorides was approximately 0.17% of the Korea occupational exposure limits, with hydrofluoric acid at about 0.2%, hydrochloric acid 0.06%, nitric acid 0.05%, isopropyl alcohol 0.4%, and phosphine at about 2%. The maximum exposure concentration of propylene glycol monomethyl ether acetate (PGMEA) was 0.0870 ppm, representing only 0.1% or less than the American Industrial Hygiene Association recommended standard (100 ppm). Conclusion: Benzene, a known human carcinogen for leukemia, and arsine, a hematologic toxin, were not detected in wafer fabrication sites in this study. Among reproductive toxic substances, n-butyl acetate was not detected, but fluorides and PGMEA existed in small amounts in the air. This investigation was focused on the air-borne chemical concentrations only in regular working conditions. Unconditional exposures during spills and/or maintenance tasks and by-product chemicals were not included. Supplementary studies might be required.

• Journal of Environmental Science International
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• v.26 no.9
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• pp.1013-1021
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• 2017

Exposure to Diesel Particulate Matter (DPM) potentially causes adverse health effects (e.g. respiratory symptoms, lung cancer). Due to a lack of data on Elemental Carbon (EC) exposure levels in underground copper ore mining (unlike other underground mining industries such as non-metallic and coal mining), this case study aims to provide individual miners' EC exposure levels, and information on their work practices including use of personal protective equipment. EC measurement was carried out during different work activities (i.e. drilling, driving a loader, plant fitting, plant operation, driving a Specialized Mining Vehicle (SMV)) as per NIOSH Method 5040. The copper miners were working 10 h/day and 5 days/week. This study found that the most significant exposures to EC were reported from driving a loader (range $0.02-0.42mg/m^3$). Even though there were control systems (i.e. water tanks and DPM filters) on the diesel vehicles, around 49.5% of the results were over the adjusted recommendable exposure limit ($0.078mg/m^3$). This was probably due to: (1) driver's frequently getting in and out of the diesel vehicles and opening the windows of the diesel vehicles, and (2) inappropriate maintenance of the diesel vehicles and the DPM control systems. The use of the P2 type respirator provided was less than 19.2%. However, there was no significant difference between the day shift results and the night shift results. In order to prevent or minimize exposure to EC in the copper ore mine, it is recommended that the miners are educated in the need to wear the appropriate respirator provided during their work shifts, and to maintain the diesel engine and emission control systems on a regular basis. Consideration should be given to a specific examination of the diesel vehicles' air-conditioning filters and the air ventilation system to control excessive airborne contaminants in the underground copper mine.