• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.4
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• pp.59-68
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• 2009

This paper addresses a hybrid multi-focus image fusion scheme using the recent curvelet transform constructions. Hybridization is obtained by combining the MS fusion rule with a novel "copy" method. The proposed scheme use MS rule to fuse the m most significant terms in spectrum of an image at each decomposition level. The scheme is dubbed in this work as m-term fusion in adherence to its use of the MSC (most significant coefficients) in the transform set at any given scale, orientation, and translation. We applied the edge-sensitive objective quality measure proposed by Xydeas and Petrovic to evaluate the method. Experimental results show that the proposed scheme is a potential alternative to the redundant, shift-invariant Dual-Tree Complex Wavelet transforms. In particular, it was confirmed that a 50% m-term fusion produces outputs with no visible quality degradation.

• Korean Journal of Occupational Health Nursing
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• v.23 no.3
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• pp.123-133
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• 2014

Purpose: The purpose of this study was to investigate the relationships among self-efficacy, collective efficacy, job satisfaction, and organizational commitment of nurses working in general hospitals. Methods: Data were collected from 239 nurses working in five general hospitals of a local area by self-reported questionnaires. The collected data were analyzed with descriptive statistics, t-test, ANOVA, Pearson's correlation, and hierarchial multiple regression. Results: Self-efficacy, collective efficacy, job satisfaction, and organizational commitment showed significantly positive correlations. Hierarchial multiple regression analysis showed that self-efficacy was the main factor of affecting job satisfaction, which explained 14.3% of the variance for the nurses' job satisfaction together with collective efficacy and weekly working time. In addition, the primary factor of affecting organization commitment was self-efficacy, which accounted for 17.2% of the variance for the nurses' organizational commitment together with hospital size and shift work. Conclusion: Self-efficacy and nursing working condition such as working time or hospital size contributed to the job satisfaction and organizational commitment and collective efficacy contributed to the job satisfaction. Therefore, the strategies for improving self and collective efficacy should be considered. Further study is also needed to investigate the concept of collective efficacy and its' measurement, and the relationship between collective efficacy and organizational commitment.

• Elastomers and Composites
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• v.42 no.1
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• pp.55-58
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• 2007

Thermal Characterization of an EPDM/IIR rubber blend was performed using TG/DTG analysis. While TGA thermograms of a virgin EPDM and IIR showed their own characteristic thermal decomposition curves, that of an EPDM/IIR blend sample showed a characteristic curve, exhibiting both decomposition characteristics of EPDM and IIR. This finding was more clarified from DTG analysis obtained by differentiation of TGA thermograms, being exhibited as two distinct shifted-peaks. Degrees of peak-shift (${\Delta}T$) compared to their original positions were $+25\;^{\circ}C$ for IIR and $-15\;^{\circ}C$ for EPDM, respectively. From these facts, thermal stability of EPDM is considered comparatively better than IIR, and moreover, it can be an evidence for the characteristics of a partial compatibility between EPDM and IIR. It is noteworthy that, if we prepare in advance a calibration curve for the composition about EPDM/IIR blend, it may be possible to analyze quantitatively an EPDM/IIR blend, using comparatively simple TGA experiments as in the present work.

• Journal of Preventive Medicine and Public Health
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• v.27 no.3 s.47
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• pp.487-504
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• 1994

A cross-sectional study was performed to evaluate the effects of chronic low-dose solvent on neurobehavioral performance of 118 male car painters. A control group of 113 workers matched for age was selected from different sections of the factory. The mean age and the mean duration of employment were 33 years and 6.7 years in both groups. Mean years of education were 11.4 years in car painters and 11.8 years in controls. Each worker completed a medical and occupational questionnaire and four tests of Swedish performance evaluation system. These included simple reaction time, symbol digit, digit span and finger tapping speed. Althougth the mean duration of employment was 6.7 years, comparison of mean performance showed a significantly poorer performance on simple reaction time (p<0.05), symbol digit(p<0.01) and digit span(p<0.05) in car painters. In univariate analysis, age and educational level contributed to poorer performance on symbol digit and digit span. Smoking appeared to slow finger tapping speed in car painters. Performance of four tests of car painters exposed to high level of solvent was poorer than that of car painters exposed to low level. In multiple regression models, controlling for age, alcohol, smoking and shift work, solvent exposure was found to be associated with performance of simple reaction time, symbol digit and digit span and exposure to high level of solvent was related to poorer performance of symbol digit and digit span.

• Journal of Sensor Science and Technology
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• v.6 no.4
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• pp.252-257
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• 1997

Organic EL devices, which have the sing3e-layer structure of ITO(indium-tin-oxide) /PPV(poly(p-phenylene vinylene))/cathode and the double-layer structure of ITO/PVK (poly(N- vinylcarbazole)) /PPV/cathode, were fabricated and their electro-optical properties were investigated. Experimental results, in single-layer structure, shown that the increment of temperature for thermal conversion of PPV film from $140^{\circ}C$ to $260^{\circ}C$ decreases the maximum luminance from $118.8\;cd/m^{2}$(20V) to $21.14\;cd/m^{2}$(28V) and shift the maximum peak of EL spectrum from 500nm to 580nm. The lower the work function of cathode is, the more the luminance and injection current of device. In double-layer structure, as the concentration of PVK solution decreases from 0.5 wt% to 0.05 wt%, the luminance of device increases from $70.71\;cd/m^{2}$(32V) to $152.7\;cd/m^{2}$(26V).

• Environmental Engineering Research
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• v.17 no.4
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• pp.179-184
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• 2012

The light absorbance of photocatalysts and reaction kinetics of environmental pollutants at the liquid-solid and gas-solid interfaces differ from each other. Nevertheless, many previous photocatalytic studies have applied the science to aqueopus applications without due consideration of the environment. As such, this work reports the surface and morphological characteristics and photocatalytic activities of carbon-embedded (C-$TiO_2$) photocatalysts for control of gas-phase methyl tertiary-butyl ether (MTBE) under a range of different operational conditions. The C-$TiO_2$ photocatalysts were prepared by oxidizing titanium carbide powders at $350^{\circ}C$. The characteristics of the C-$TiO_2$ photocatalysts, along with pure TiC and the reference pure $TiO_2$, were then determined by X-ray diffraction, scanning emission microscope, diffuse reflectance ultraviolet-visible-near infrared (UV-VIS-NIR), and Fourier transform infrared spectroscopy. The C-$TiO_2$ powders showed a clear shift in the absorbance spectrum towards the visible region, which indicated that the C-$TiO_2$ photocatalyst could be activated effectively by visible-light irradiation. The MTBE decomposition efficiency depended on operational parameters, including the air flow rate (AFR), input concentration (IC), and relative humidity (RH). As the AFRs decreased from 1.5 to 0.1 L/min, the average efficiencies for MTBE increased from 11% to 77%. The average decomposition efficiencies for the ICs of 0.1, 0.5, 1.0, and 2.0 ppm were 77%, 77%, 54%, and 38%, respectively. In addition, the decomposition efficiencies for RHs of 20%, 45%, 70%, and 95% were 92%, 76%, 50%, and 32%, respectively. These findings indicate that the prepared photocatalysts could be effectively applied to control airborne MTBE if their operational conditions were optimized.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.11
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• pp.2671-2676
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• 2015

Nowadays, Mobile devices are now capable of supporting a wide range of applications. Unfortunately, some of applications demand an ever increasing computational power and mobile devices have limited resources due to their constraints, such as low processing power, limited memory, unpredictable connectivity, and limited battery life. To deal with mobile devices' constraints, researchers envision extending cloud computing services to mobile devices using virtualization techniques to shift the workload from mobile devices to a powerful computational infrastructure. Those techniques consist of migrating resource-intensive computations from a mobile device to the resource-rich cloud, or server (called nearby infrastructure). In this paper, we want to highlight on cloudlet architecture (nearby infrastructure with mobile devices), its functioning and in our future work, analyze effects of distance between cloudlet and mobile devices.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.8
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• pp.2164-2172
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• 2009

The purpose of the present study was intended to assess fatigue symptoms of nurses working at special part(operating room, intensive care unit, emergency room) and ward in general hospitals, and to reveal its related factors. The self-administered questionnaires were given to 393 nurses employed in 3 participating hospitals located in Daejeon City. As a results, the special part workers had higher scores of fatigue symptoms than the ward workers. Multiple stepwise analysis revealed that the factors of influence on fatigue symptoms in the special part workers included subjective health status, age and job satisfaction, and in the ward workers, the factors of influence on fatigue symptoms included subjective health status, sleep hour, shift work and job satisfaction. In conclusion, the fatigue symptoms were higher in the special part workers than the ward workers, and its related factors were different from two worker groups.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.124-124
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• 2010

Much interest has been focused on InGaN-based materials and their quantum structures due to their optoelectronics applications such as light emitting diode (LED) and photovoltaic devices, because of its high thermal conductivity, high optical efficiency, and direct wide band gap, in spite of their high density of threading dislocations. Build-in internal field-induced quantum-confined Stark effect in InGaN/GaN quantum well LED structures results in a spatial separation of electrons and holes, which leads to a reduction of radiative recombination rate. Therefore, many growth techniques have been developed by utilizing lateral over-growth mode or by inserting additional layers such as patterned layer and superlattices for reducing threading dislocations and internal fields. In this work, we investigated various characteristics of InGaN multiple quantum wells (MQWs) LED structures grown on selectively wet-etched porous (SWEP) GaN template layer and compared with those grown on non-porous GaN template layer over c-plane sapphire substrates. From the surface morphology measured by atomic force microscope, high resolution X-ray diffraction analysis, low temperature photoluminescence (PL) and PL excitation measurements, good structural and optical properties were observed on both LED structures. However, InGaN MQWs LED structures grown on SWEP GaN template layer show relatively low In composition, thin well width, and blue shift of PL spectra on MQW emission. These results were explained by rough surface of template layer, reduction of residual compressive stress, and less piezoelectric field on MQWs by utilizing SWEP GaN template layer. Better electrical properties were also observed for InGaN MQWs on SWEP GaN template layer, specially at reverse operating condition for I-V measurements.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.27 no.1
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• pp.23-37
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• 2017

Objectives : This study was conducted to evaluate the level of exposure to volatile organic compounds (VOCs) among workers handling rust preventive oils. Methods : A total of 30 bulk samples and 54 personal air samples were collected using diffusive samplers at 22 workplaces handling rust preventive oils in Daegu and Gyongsangbuk-do Province from March to October 2013. We also investigated detailed information on the related work conditions, such as kinds of products, handling methods, local exhaustive ventilation systems, and the status of the wearing personal protective equipment. All bulk samples and air samples were analyzed using gas chromatography mass spectrometry (GC-MS) to identify components to which workers potentially were exposed. Quantitative airborne concentrations of VOCs were confirmed using gas chromatography with flame ionized detectors. Results : In terms of qualitative analyses for the 30 bulk samples, we found carcinogenic, mutagenic and reproductive toxic(CMR) substances such as butane(carcinogenic Group 1A, mutagenic Group 1B), butoxy ethanol(carcinogenic Group 2), cumene (carcinogenic Group 2), ethyl benzene(carcinogenic Group 2), methyl isobutyl ketone(carcinogenic Group 2) and toluene (reproductive toxic, Group 2). As a result of full-shift based personal air samples, eight substances such as n-hexane, n-heptane, octane, nonane, decane, toluene, ethyl benzene and xylene were detected. Among them, n-hexane and n-heptane were detected in all of 54 air samples with $13.13mg/m^3$ and $8.61mg/m^3$ of maximum concentration, respectively. The level of airborne concentration from all of samples were bellow the occupational exposure limit in Korea. Conclusions : Based on the results of this study, workers handling rust preventive oils could be exposed to CMR substances contained in rust preventive oils and n-hexane and n-heptane were found as the most frequent sources of VOC exposure.