• Journal of Korean Society of Occupational and Environmental Hygiene
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• 제29권3호
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• pp.404-413
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• 2019

Objectives: Chronic obstructive pulmonary disease(COPD) is an important cause of mortality in workers exposed to hazardous dust, such as crystalline silica or coal, and COPD is related to inflammation and oxidative stress in the lung. The aim of this study was to evaluate the association of oxidative stress and inflammation to COPD in retired workers exposed to mineral dust. Methods: The levels of malondialdehyde(MDA) in EBC as biomarkers for oxidative stress and C-reactive protein(CRP) and lactate dehydrogenase(LD) as biomarkers for inflammation were measured in 107 male subjects(63 pneumoconiosis and 42 COPD subjects). Results: Mean levels of EBC MDA(2.03 nmol/L vs. 4.65 nmol/L, p=0.010) and serum LD(170.3 U/L vs. 185.9 U/L, p=0.022) were significantly higher in subjects with COPD, but mean levels of serum CRP(p=0.469) did not show a statistical difference between the study groups. Level of EBC MDA was negatively correlated with ${%}FEV_1$ predicted(r=-0.279, p=0.004) and ${%}FEV_1/FVC$ ratio(r=-0.397, p<0.001). Conclusions: These results suggest that EBC is a useful biological matrix for investigation of respiratory oxidative stress. High levels of EBC MDA and serum LD are related to COPD in retired workers exposed to mineral dust.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• 제31권4호
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• pp.461-472
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• 2021

Objectives: This study was conducted to determine the differences in EC concentrations according to the type of sampler by measuring and analyzing EC. Methods: Elemental carbon was measured in diesel engine vehicles and at the roadside. Using NIOSH method 5040, a cassette was coupled to 37 mm and 27 mm quartz filters and measurements were performed 21 times. There were 14 types of measurement methods, and polystyrene, polypropylene, and metal samplers were evenly placed inside the movable chamber. Results: The results measured using the 37 mm conductive cassette (closed/open) and the IOM sampler made of conductive materials showed a higher ratio than the other results. When the 37 mm conductive cassette was measured with the lid open, it showed a statistically significantly higher ratio than with other measurement methods (p<0.05). Conclusions: Checking the EC concentration a total of 21 times at each ratio based on the concentration of the 3-stage polystyrene cassette, it was statistically significantly higher when the 37 mm conductive cassette was open. This same cassette also showed a slightly higher EC concentration when closed. It was ascertained that some DEE was collected on the cassette wall surface due to the electrical conductivity of the polystyrene cassette, resulting in sample loss. Since EC is composed of fine particles, it is thought that electrical conductivity may affect its concentration.

• The Transactions of the Korean Institute of Power Electronics
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• 제26권2호
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• pp.90-95
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• 2021

In contrast to AC grounding systems, the ground electrode in DC systems continuously maintains positive or negative polarity. Ground electrodes with (+) polarity proceeds by oxidation reaction. Thus, the DC current should flow opposite to the polarity of the leakage current flowing through the (+) ground electrode by using a compensation electrode, and the current flowing through the (+) ground electrode can be 0A. However, according to protecting the (+) ground electrode, the compensation electrode corrodes and gets damaged. Thus, the (+) ground electrode must be protected from corrosion, and the service life of the compensation electrode must be extended. As an alternative, the average value of the current flowing through the compensation electrode should be equal with the value of the leakage current flowing through the (+) ground electrode by using the square waveform. Throughout the experiment, the degree of corrosion on the compensation electrode is analyzed by the frequency of the compensation electrode for a certain time. In the experiment, the frequencies of the square waveform are considered for 0.1, 1, 10, 20, 50, 100 Hz, and 1 kHz. Through experiments and analysis, the optimal frequency for reducing the electrolytic damage of the (+) electrode and compensation electrode in an LVDC grounding environment is determined.

• ETRI Journal
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• 제29권3호
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• pp.371-380
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• 2007

This paper proposes a new automatic compensation network (ACN) for a system-on-chip (SoC) transceiver. We built a 5 GHz low noise amplifier (LNA) with an on-chip ACN using 0.18 ${\mu}m$ SiGe technology. This network is extremely useful for today's radio frequency (RF) integrated circuit devices in a complete RF transceiver environment. The network comprises an RF design-for-testability (DFT) circuit, capacitor mirror banks, and a digital signal processor. The RF DFT circuit consists of a test amplifier and RF peak detectors. The RF DFT circuit helps the network to provide DC output voltages, which makes the compensation network automatic. The proposed technique utilizes output DC voltage measurements and these measured values are translated into the LNA specifications such as input impedance, gain, and noise figure using the developed mathematical equations. The ACN automatically adjusts the performance of the 5 GHz LNA with the processor in the SoC transceiver when the LNA goes out of the normal range of operation. The ACN compensates abnormal operation due to unusual thermal variation or unusual process variation. The ACN is simple, inexpensive and suitable for a complete RF transceiver environment.

• Korean Journal of Occupational Health Nursing
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• 제18권2호
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• pp.262-269
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• 2009

Purpose: The purpose of this study was to explore job stress, job satisfaction and their relationship among Workers' Compensation Case Managers. Method: 137 Workers' Compensation Case Managers (89 case workers and 48 nurses) responded to a self-administered questionnaire. The data were collected in october, 2006 and analyzed using t-test and Pearson's Correlation Coefficient with SPSS WIN 14.0 program. Result: The mean score of job stress of nurses was 2.60 which was higher than that of the Korean female workers'. The mean score of job satisfaction was 2.30. The significant inverse correlation between job stress and job satisfaction was found (P<.01). In regard to the 7 items, the significant inverse correlations were found in lack of reward, interpersonal conflict, organizational system, insufficient job control, and occupational environment. Conclusion: The result indicated that the Workers' Compensation Case Managers have higher occupational stress and lower job satisfaction. To improve their job satisfaction, it is necessary to reinforce reward, organizational system, job autonomy, and cooperative occupational environment.

• Journal of Korean Society for Quality Management
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• 제51권3호
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• pp.445-459
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• 2023

Purpose: The present study was designed to find out how the quality of the work environment felt by physical therapists and LMX affect the turnover intention. In addition, we tried to find the mediating effect of LMX in the causal relationship between work environment quality and turnover intention, and to find ways to effectively lower the turnover intention of physical therapists. Methods: Survey tool has obtained validity and reliability through literature survey, exploratory survey and pretest and sample 365 was selected. To treat a pretest and main analysis, SPSS23.0 and AMOS23.0 were employed and structural equation model was employed as an analysis method. Results: Among the work environments, the human environment, the physical environment, and the compensation system were found to have an effect on LMX. In addition, the physical environment and compensation system were found to have a significant effect on turnover intention. LMX was found to have an effect on turnover intention and play a mediating role. Conclusion: In order to lower the turnover intention of physical therapists, the level of LMX should be increased by strengthening the factors of the working environment. This study shows that the management of LMX along with the working environment is an important factor in lowering the turnover intention of physical therapists, and this study has several limitations.

• Korean Journal of Environment and Ecology
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• 제22권5호
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• pp.536-543
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• 2008

This study was carried out to review the satisfaction with compensation for damage caused by the released Asiatic Black Bears into the whole area of Jirisan National Park and to offer basic data for reasonable conflict management with local community. A questionnaire survey was conducted from Jun. 2007 to Dec. 2007 on 93 subjects who got their compensations for the bear damage from 2004 until 2007. The results stayed at a middle level of satisfaction with the proper damage indemnity program with as mean $3.14{\pm}0.85$ points on the basis of 5 point scale. The satisfaction with compensation was found to have a significant correlation with the factors, such as income levels, whether to agree to restoration project, compensation money and compensation procedures. The compensation plan through the Animal Damage Compensation Consultation Committee was accepted positively(mean: $3.3{\pm}0.9$); however, to the compensation plan for the 80% compensation of actual amounts of bear damage, was acknowledged negatively(mean: $2.6{\pm}1.11$).

• Journal of the Korean Society of Marine Environment & Safety
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• 제11권1호
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• pp.61-70
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• 2005

The most likely influenced by the oil pollution at the sea is the fisheries industry, because if the destruction if the marine ecological system The rate if compensation for damage from IOPC Fund due to the incident if oil pollution is more or less $20\%$, which is remarkably lower than those cf our adjacent nations or European nations. The reason such a low rate cf compensation is that it is not easy to take evidences if changed caused by oil pollution requested by IOPC Fund due to the environments if our fisheries. Therefore unless the environments if our fisheries is changed completely, it is very difficult to get actual compensation for damages under the existing system, considering the results if the oil pollution damage compensation claim cases up to now. In this study tried to identify the actual benefits of 03FC convention that raises the upper limit if the compensation while keeping the criterion for compensation And proposed to supplement the compensation system of damage caused by oil pollution with analyzing the actual status if compensation from. IOPC Fund for the our oil pollution incidents and the judgment if Supreme Court on the case if oil. pollution acident in Keumdong No.5.

• Journal of Labour Economics
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• 제39권1호
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• pp.33-55
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• 2016

This paper examines the role of adverse working environments in the determination of workers' compensation in South Korean. I use the Third Korean Working Conditions Survey(2011), Occupational Safety and Health Research Institute that provide relevant variables in objective and subjective compensation and workers of diverse working environment. I find that risk factors in adverse working environments have a very minor role in the determination of individual wages. In contrast, adverse working environments have significant relationship with the level of compensation satisfaction. In addition, the results show that workers are more likely to receive compensation from psychological risk than physical risk. And women receive much more compensation in the psychological risk. These results provide useful information for improvement of working environments.

• The Journal of Korean Institute of Communications and Information Sciences
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• 제37권6C호
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• pp.492-496
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• 2012

This paper presents a decoding technique for speech recognition using uncertainty information from feature compensation method to improve the speech recognition performance in the low SNR condition. Traditional feature compensation algorithms have difficulty in estimating clean feature parameters in adverse environment. Those algorithms focus on the point estimation of desired features. The point estimation of feature compensation method degrades speech recognition performance when incorrectly estimated features enter into the decoder of speech recognition. In this paper, we apply the uncertainty information from well-known feature compensation method, such as IMM, to the recognition engine. Applied technique shows better performance in the Aurora-2 DB.