• Journal of Advanced Marine Engineering and Technology
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• v.41 no.1
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• pp.99-104
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• 2017

This study evaluated the heating performance of a hybrid heat pump system. The system was installed in a $100-m^2$ greenhouse to utilize surplus solar energy. A hybrid heat pump system was installed at Jocheon-ri, Jeju Island, for an empirical evaluation of the performance. The system consists of a heat storage tank and plate heat exchangers for several heat exchanges between the greenhouse and heat pump or storage tank. The system uses R410a as the working fluid and is controlled automatically by a defined set temperature of the greenhouse. This system incorporates two kinds of heat sources: outdoor air and a storage tank that collects heat from the topside of the greenhouse. The results showed that the heating capacity was 19.9 kW in the outdoor air source mode and 21.4 kW with direct heating from hot water in the thermal storage tank. These results are very similar to those of a previous study.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.6
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• pp.592-598
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• 2015

In this study, we experimentally investigate the performance characteristics of a high-performance summer-cooling heat pump for an R410A by applying an air-cooled-type vapor-injection (VI) cycle. The devices used for the experiment consist of a VI compressor, condenser, oil separator, plate-type heat-exchanger, economizer, evaporator, and re-cooler. The experimental conditions employed for the cooling performance were divided into three cycles. First, in Cycle A, we apply a VI cycle and with no heat exchange between the evaporator outlet refrigerant and the VI cycle suction refrigerant in the re-cooler. For Cycle B, there is heat exchange, and for Cycle C, there is neither a VI cycle nor heat exchange between the evaporator outlet refrigerant and the VI cycle suction refrigerant. From the analysis results, we observe that the performance was highest in the VI cycle with heat exchange between the evaporator outlet refrigerant and the VI cycle suction refrigerant (Cycle B), while it was lowest in Cycle C without application of the VI cycle. Moreover, the cooling coefficient of Performance ($COP_C$) averaged 3.5 in Cycle B, which was 8.6% higher than the corresponding value in Cycle A, and 33% higher than that in Cycle C.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.12
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• pp.163-173
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• 2014

When evaluating the spatial resolution images and evaluation of low contrast resolution using CT standard phantom, and might present a automated quantitative evaluation method for minimizing errors by subjective judgment of the evaluator be, and try to evaluate the usefulness. 120kVp and 250mAs, 10mm collimation, SFOV(scan field of view) of 25cm or more than, exposure conditions DFOV(display field of view) of 25cm, and were evaluated the 24 passing images and 20 failing images taken using a standard reconstruction algorithm by using the Nuclear Associates, Inc. AAPM CT Performance Phantom(Model 76-410). Quantitative evaluation of low contrast resolution and spatial resolution was using an evaluation program that was self-developed using the company Mathwork Matlab(Ver. 7.6. (R2008a)) software. In this study, the results were evaluated using the evaluation program that was self-developed in the evaluation of images using CT standard phantom, it was possible to evaluate an objective numerical qualitative evaluation item. First, if the contrast resolution, if EI is 0.50, 0.51, 0.52, 0.53, as a result of evaluating quantitatively the results were evaluated qualitatively match. Second, if CNR is -0.0018~-0.0010, as a result of evaluating quantitatively the results were evaluated qualitatively match. Third, if the spatial resolution, as a result of using a image segmentation technique, and automatically extract the contour boundary of the hole, as a result of evaluating quantitatively the results were evaluated qualitatively match.

• Food Science and Preservation
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• v.10 no.3
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• pp.406-410
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• 2003

For selection of lactic acid bacteria for probiotics, we have examined isolated strains from Korean Dongchimi to assess the acid, bile, and pancreatic tolerance and the growth inhibition on the pathogens. Especially, a kind of isolated strains, FF-3 showed the highest resistancy to both of HCl and bile salt, as well as the highest inhibitory activities against Salmonella sp. and Escherichia coli. Further the bacteriocin of FF-3 showed relatively wide range of inhibition spectrum against gram positive and some gram negative bacterias. By using 16s rDNA sequencing method, FF-3 of the selected lactic acid bacteria were found to be identified as genus Lactobacillus.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.7
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• pp.353-362
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• 2019

Thermodynamic analysis of cascade refrigeration systems has attracted considerable research attention. On the other hand, a system evaluation based on thermodynamic analyses of the individual parts, including the evaporator, condenser, intercooler, expansion valve, etc., has received less attention. In this study, performance analysis was conducted on a cascade refrigeration system, which has an individual cooling and refrigeration evaporator, and equips the intercooler and air-cooled condenser in a series in a lower cycle. The thermo-fluid design was then performed on the major components of the system - upper condenser, lower condenser, cooling evaporator, refrigeration evaporator, intercooler, compressor, electronic expansion valve - of 15 kW refrigeration, and 8 kW cooling capacity using R-410A. A series of simulations were conducted on the designed system. The change in outdoor temperature from 26 C to 38 C resulted in the cooling capacity of the lower evaporator remaining approximately the same, whereas it decreased by 9% at the upper evaporator and by 63% at the intercooler. The COP decreased with increasing outdoor temperature. In addition, the COP of the cycle with the intercooler operation was higher that of the cycle without the intercooler operation. Furthermore, the increase in the upper condenser size by two fold increased the upper evaporator by 4%. On the other hand, the lower evaporator capacity remained the same. The COP of the upper cycle increased with increasing upper condenser size, whereas that of the lower cycle remained almost the same. When the size of the lower condenser was increased 2.8 fold, the intercooler capacity increased by 8%, whereas those of upper and the lower evaporator remained approximately the same. Furthermore, the COP of the lower cycle increased with an increase in the lower condenser. On the other hand, the change of the upper condenser was minimal.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.10
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• pp.373-381
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• 2016

This research is a descriptive correlation research to examine the relationship among stress, coping behaviors, and perceived social support in school-age children. Students in third, fourth, and fifth grades at one elementary school in A metropolitan city were included for this research. A researcher of the study visited the elementary school and obtained appropriate approval to conduct this survey. Then, a total of 481 students answered the questionnaire; finally, the questionnaires of 409 students were analyzed after excluding 72 questionnaires due to unreliable responses. Descriptive statistics, T-test, ANOVA, and Pearson's correlation were used to analyze the collected data with SPSS 13.0. In the stress scores, academic stress was associated with the highest score ($9.30{\pm}4.41$). With respect to stress coping behaviors, lower-grade students showed to have significantly higher scores in coping behavior of pursuing social support than higher-grade students (F=3.181, p=.043); male students had higher scores in aggressive coping behavior than female students (t=-3.399, p=.001). Perceived social support scores were higher in the following order: family members ($33.01{\pm}7.61$), friends ($28.43{\pm}7.89$), and teachers ($25.71{\pm}6.30$). Female students had higher scores in perceived social support from friends (t=3.842, p=.000) and teachers (t=3.037, p=.003) than the male students. As the stress scores increased, passive coping behaviors (r=.410, p=.000) and aggressive coping behaviors (r=.445, p=.000) have been significantly increased. As perceived social support is higher, active coping behaviors (r=.455, p=.000) and coping behaviors to pursue social support (r=.429, p=.000) were significantly increased. Therefore, we can conclude that stress management is very significant for children. It would be necessary to develop nursing intervention programs in order to reduce the aggressive and passive coping behaviors of children and encourage perceived social support.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.282-282
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• 2009

Forest Fire can cause a serious damage to overhead conductors. Therefore, the detailed investigation for the changes of mechanical and electrical properties of damaged conductors should be carried out to understand the effect of forest fires on conductors. This is very important to maintain transmission line safely. Specimenes for this study were Al conductores of ACSR $410mm^2$, ACSR 480 R and ACSR $240mm^2$. This paper describes the changes of mechanical and electrical properties of same flame exposed Al conductor. The detailed will be given in the text.

• Kyungpook Mathematical Journal
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• v.51 no.4
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• pp.395-410
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• 2011

In this paper we give a non-existence theorem for Hopf hypersurfaces M in complex two-plane Grassmannians $G_2(\mathbb{C}^{m+2})$ whose normal Jacobi operator $\bar{R}_N$ is parallel on the distribution F defined by $F=[{\xi}]{\cup}D^{\bot}$, where [${\xi}$] = Span{${\xi}$}, $D^{\bot}$ = Span {${\xi}_1$, ${\xi}_2$, ${\xi}_3$} and $T_xM=D{\oplus}D^{\bot}$, $x{\in}M$.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.8
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• pp.4315-4328
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• 2019

The present study investigated the effects of work satisfaction on quality of life for 119 paramedics, the Korean equivalent of 911 paramedics. Data collection began in July 2017 and lasted for six months. Data was collected from 410 119 paramedics of the J province and the G metropolitan area who consented to study participation. The results showed that the higher the job satisfaction of the participants, the higher the quality of life (r = 0.508, p = 0.008). The factors affecting the quality of life were leisure activity, subjective health, and job satisfaction. For 119 paramedics to improve their quality of life, they need to relieve work stress and fatigue through leisure activities, and recover and maintain their health through sufficient rest. Moreover, returning to work in a healthy state likely leads to increased job satisfaction, and the quality of life will increase accordingly. Therefore, 119 paramedics should be permitted to have plenty of leisure time outside their work hours and should be able to maintain health through periodic health checks.

• Journal of Environmental Health Sciences
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• v.30 no.5 s.81
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• pp.410-416
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• 2004

The objective of this investigation was to evaluate applicability of precoat filtration that can be substituted for rapid sand filter of conventional water treatment system(CWTS). Precoat filter used in this experiment are candle filter. Element disk of candle are pore size $10{\mu}m(R),\;20{\mu}m(B)$ And diatomaceous earth are cake pore size $3.5{\mu}m$(Standard Super- Cel; A), $7{\mu}m$(Hyflo Super-Cel; B) and $17{\mu}m$(Celite 545RV; C). $2kg/m^2$ diatomaceous earth is used for precoating, it coated candle in $5{\sim}6mm$ thickness. 1. Al adsorption dosages by diatomaceous earth used in experimental we Hyflo Super-Cel 0.843mg/g, Standard Super-Cel 0.782 mg/g and Celite 545RV 0.766 mg/g. 2. Filtrate of precoat filter during 60min are R-C combination 20.7($m^3/m^2$)>B-C 18.3($m^3/m^2$)>B-B 15.0($m^3/m^2$)> R-B 12.9($m^3/m^2$)> R-A 11,093($l/m^2$). 3. Water quality of precoat filter effluent are thus. $KMnO_4$ consumption are $1.10{\sim}2.20mg/l$, removal rate are $30.9{\sim}65.6\%$. They are R-A 1.10(mg/l)(removal rate $65.6\%$). R-C(2.20 mg/l)(removal rate $30.9\%$). 4. $Al^{3+}$ are not detected with all combination, removal rate $100\%$. 5. Considering water quality and flux, continued running time of R-A combination is 7 hr. Accumulated filtrate are $74.4 m^3/m^2$, average flux is $177.2 l/m^2{\cdot}min$. And filtrate per diatomaceous earth 1g are 37.2 l. 6. R-A effluent's water quality are $KMnO_4$ Consumption 1.10(mg/l), DOC 1.161 mg/1, Al 0.0 mg/1, $UV_{254}$ 0.016/cm, Turbidity 0.1(NTU). R-A combination is suitable to precoat filtration for the settling basin effluent treatment.