• Journal of Advanced Marine Engineering and Technology
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• v.39 no.9
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• pp.870-875
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• 2015

Diesel engines are widely used due to superior power and fuel consumption, however there are many challenges in exhaust gas management. Exhaust gas recirculation (EGR) is the most effective technique for reducing mono-nitrogen oxide (NOx) emissions in a diesel engine, in comparison with other catalytic technologies. In addition, the technology has a number of advantages in terms of economic efficiency and implementation. In this study, the effects on the power and exhaust characteristics of diesel engines equipped with EGR systems were investigated. It was found that as the EGR rate increased, horsepower expressed as IHP and BHP decreased. The net effect of the application of EGR was measured at various engine speeds. EGR technology caused decreases in BHP of around 9% during low engine speed and 3.5% during high engine speed. Additionally, NOx emissions reduced as the EGR rate increased, and increased as engine speed increased. However, smoke emissions increased as the EGR rate increased, and decreased as engine speed increased. The optimum operating conditions and ERG rate to simultaneously achieve minimum NOx and smoke emissions were investigate. It was found that as the EGR rate increased, optimal operating speed for minimal NOx and smoke also increased. Keywords: Diesel engine, Exhaust gas recirculation, Power perfomance, Emission characteristics, NOx, Smoke

• Korean Journal of Remote Sensing
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• v.37 no.5_2
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• pp.1317-1328
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• 2021

This study analyzes the early satellite mission marine fog detection results from Geostationary Ocean Color Imager-II (GOCI-II). We investigate optical characteristics of the GOCI-II spectral bands for marine fog between October 2020 and March 2021 during the overlapping mission period of Geostationary Ocean Color Imager (GOCI) and GOCI-II. For Rayleigh-corrected reflection (R_rc) at 412 nm band available for the input of the GOCI-II marine fog algorithm, the inter-comparison between GOCI and GOCI-II data showed a small Root Mean Square Error (RMSE) value (0.01) with a high correlation coefficient (0.988). Another input variable, Normalized Localization Standard (NLSD), also shows a reasonable correlation (0.798) between the GOCI and GOCI-II data with a small RMSE value (0.007). We also found distinctive optical characteristics between marine fog and clouds by the GOCI-II observations, showing the narrower distribution of all bands' R_rc values centered at high values for cloud compared to marine fog. The GOCI-II marine fog detection distribution for actual cases is similar to the GOCI but more detailed due to the improved spatial resolution from 500 m to 250 m. The validation with the automated synoptic observing system (ASOS) visibility data confirms the initial reliability of the GOCI-II marine fog detection. Also, it is expected to improve the performance of the GOCI-II marine fog detection algorithm by adding sufficient samples to verify stable performance, improving the post-processing process by replacing real-time available cloud input data and reducing false alarm by adding aerosol information.

• Journal of Mushroom
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• v.17 no.1
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• pp.7-11
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• 2019

We assessed the growth characteristics of Auricularia polytricha 'Geoni' cultivated in a simple greenhouse constructed of polyethylene (PE) without air conditioning (high temperature) and in an air conditioned mushroomhouse. The successful cultivation of A. polytricha 'Geoni' at high temperatures can reduce energy and facility investment costs. The comparison of growth characteristics of the fungi grown under the different temperature conditions revealed that fruit bodies were larger in the higher temperature condition, but were brighter in the lower temperature condition. Additionally, fruit body physiology was found to be not affected by temperature. In the PE greenhouse, the fresh weight of fruit body was higher in mid-June and early July. Therefore, it was possible to effectively control the growth period of the mushrooms during a high-temperature period. The findings indicate the potential to cultivate A. polytricha 'Geoni' in a simple PE greenhouse that is not cooled in summer, thus reducing energy costs.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.2
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• pp.138-147
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• 2009

In this paper, improved direct torque control(DTC) system for five-phase squirrel-cage induction motor(IM) is proposed. Due to the additional degrees of freedom, five-phase 1M drives present unique characteristics. Also five-phase motor drives possess many other advantages compared with the traditional three-phase motor drive system, such as reducing an amplitude of torque pulsation and increasing the reliability. The DTC method is advantageous when it is applied to the five-phase IM, because the five-phase inverter provides 32 space vectors in comparison to 8 space voltage vectors into the three-phase inverter. However, five-phase motor has structural drawback of 3rd space-harmonics current component, it is necessary to controlled 3rd harmonic current. So to control 3rd harmonic current and enhance dynamic characteristics of five-phase squirrel-cage IM drive, modified DTC method should be demanded. The characteristics and dynamic performance of traditional five-phase DTC are analyzed and new DTC for five-phase IM is presented. A more precise flux and torque control algorithm for the drives can be suggested and explained For presenting the superior performance of the proposed direct torque control, experimental results are presented using a 32-[bit] fixed point TMS320F2812 digital signal processor with 2.2[kW] induction motor.

• Journal of Korean Academy of Nursing
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• v.30 no.4
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• pp.1045-1054
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• 2000

As cost pressures have escalated, policy makers, politicians, health care providers and families have tried to devise ways to reduce health care costs. While originally developed to enhance patient control and to provide better care at the end of life, hospice care has recently received significant attention as a mean of reducing health care costs. As a program providing care for patients who are dying at their homes, hospice has expanded slowly since the opening of the first hospice in Korea in 1963. Therefore, a variety of services that responds to the needs and concerns of many dying people and their families is limited The purpose of this study was to determine the potential cost savings at the end of life among patients who used home hospice compared with the patients who received institutional care in Korea. This study used a retrospective, descriptive design. The sample for this study included 46 patients who died of lung cancer: 25 patients who received home hospice care and 21 patients who received institutional care. Data on patient characteristics, kinds and frequencies of provided treatment and nursing services, and hospice and hospital charges during the last month before death were collected. Cost of care was measured by the average cost per patient per day in the last month of life. The results of the study indicated that there were significant differences in average cost of care between home hospice sample and institutional care sample (t=9.956, p<.001; home hospice sample: M=18,102 won, institutional care sample: M=317,578 won). The cost of the home hospice sample was approximately 6% of the cost of institutional care. The majority of the home hospice nursing services were education (35.7%) and supportive counseling (25.2%), followed by medication management (13.6%), assessment (12.1%), basic nursing (7.2%), treatment (5.5%) and others. In institutional care sample, basic nursing and treatment were more emphasized than education or supportive counseling among the nursing services provided. The results of this study showed the potential for hospice to reduce costs and implications for policymakers and clinicians to incorporate hospice program into the formal health care delivery system in Korea.

• Journal of the Korean Wood Science and Technology
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• v.34 no.5
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• pp.42-51
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• 2006

The this study, the effect of rice husk flour (RHF) as scavenger on formaldehyde emission rate and formaldehyde content from urea-formaldehyde (UF) resin bonded RHF content wood particleboards (PB). Two type of particle size ($30{\mu}m$ and $300{\mu}m$) of RHF was premixed with the UF resin at 5% and 15% by weight. The performance of UF resins is greatly influenced by the curing characteristics in their curing processing. The curing behavior was monitored activation energy ($E_a$) by DSC and pH variation according to RHF contents. PB with dimensions of $27cm{\times}27cm{\times}0.7cm$ was prepared at a specific gravity of 0.75 using $E_1$ and $E_2$ class UF resins. Formaldehyde emission and formaldehyde content from RHF filled PB bonded with UF resin was measured by 24 h desiccator and perforator method, respectively. RHF causes an increased pH of UF resin. $E_a$ of the modified UF resin decreased independently of RHF particle size. As the pH and the $E_a$ variation of the UF resin containing RHF increased, the amount of formaldehyde content decreased. The formaldehyde emission and formaldehyde content levels of the PB bonded with 15 wt% of $30{\mu}m$ RHF and $E_2$ type UF resin were low and satisfied grade $E_1$, as measured by 24 h desiccator and perforator method. The result of a comparison between 24 h desiccator and perforator test using PB showed that the linear regression analyses show a good correlation between the results for the 24 h desiccator and the perforator tests. The linear regression of a correlation between the desiccator and the perforator was Y=4.842X-0.064 ($R^2=0.989$). RHF was effective at reducing formaldehyde emission and formaldehyde content in urea-formaldehyde adhesives when used as scavenger.

• The Korean Journal of Food And Nutrition
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• v.31 no.5
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• pp.598-603
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• 2018

As basic research for optimal barley cultivars selection and technical development for quality maintenance, a total of 21 commercial malt products (for making 'Sikhye', a traditional Korean sweet drink) were collected from the Korean market. And then we analyzed the component of the barley malt products as well as conducted comparative analysis on enzyme activity and quality characteristics of the commercial barley malt products. Of the 21 barley malt products, 12 were made from 100 % barley. The result of analyzing general components of barley malts turned out different level of components; moisture 4.91~11.99%, lipid 1.71~2.48%, protein 7.80~11.97%, carbohydrate 73.64~82.24%, total starch 5.50~8.22%, reducing sugar 3.64~14.44%. As a result of measuring enzyme activity of barley malts, there was a wide range of activity difference by the product; diastatic power $36.80{\sim}94.30^{\circ}$, ${\alpha}$-amylase activity 18.17~186.50 unit/g, ${\beta}$-amylase activity 6.53~25.05 unit/g. The results of this study would be used as basic data for optimal cultivars selection to produce barley malts and technical development for quality maintenance.

• Archives of Plastic Surgery
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• v.44 no.6
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• pp.539-544
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• 2017

Background We conducted this study to identify factors that may prolong the length of the hospital stay (LHS) in patients with diabetic foot (DF) in a single-institution setting. Methods In this single-center retrospective study, we evaluated a total of 164 patients with DF, and conducted an intergroup comparison of their baseline demographic and clinical characteristics, including sex, age, duration of diabetes, smoking status, body mass index, underlying comorbidities (e.g., hypertension or diabetic nephropathy), wound characteristics, type of surgery, the total medical cost, white blood cell (WBC) count, C-reactive protein (CRP) levels, erythrocyte sedimentation rate, and albumin, protein, glycated hemoglobin, and 7-day mean blood glucose (BG) levels. Results Pearson correlation analysis showed that an LHS of >5 weeks had a significant positive correlation with the severity of the wound (r=0.647), WBC count (r=0.571), CRP levels (r=0.390), DN (r=0.020), and 7-day mean BG levels (r=0.120) (P<0.05). In multiple regression analysis, an LHS of >5 weeks had a significant positive correlation with the severity of the wound (odds ratio [OR]=3.297; 95% confidence interval [CI], 1.324-10.483; P=0.020), WBC count (OR=1.423; 95% CI, 0.046.0-356; P=0.000), CRP levels (OR=1.079; 95% CI, 1.015-1.147; P=0.014), albumin levels (OR=0.263; 95% CI, 0.113.3-673; P=0.007), and 7-day mean BG levels (OR=1.018; 95% CI, 1.001-1.035; P=0.020). Conclusions Surgeons should consider the factors associated with a prolonged LHS in the early management of patients with DF. Moreover, this should also be accompanied by a multidisciplinary approach to reducing the LHS.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.11
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• pp.1649-1657
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• 2006

In order to find an alternative source of inoculum to caecal content for studying the fermentation activity of rabbit hindgut, caecal content and faeces of 25 hybrid Hyla rabbits were used as inocula for an in vitro gas production trial. About 1 g of three substrates (dehydrated alfalfa meal, dehydrated beet pulp, barley) was weighed, in quadruplicate per inoculum, in 120 ml bottles; 75 ml of anaerobic medium and 4 ml of reducing solution were added and bottles were placed at $39^{\circ}C$. Caecal content and faeces were diluted respectively 1:2 (CI) and 1:8 (FI) with anaerobic medium and were introduced in the respective bottles (10 ml). Gas production was recorded 20 times at 2-24 h intervals throughout fermentation (96 h). The fermentation characteristics (i.e. degraded organic matter, OMd; potential gas production, A; fermentation rate, Rmax; time at which it is reached, Tmax; pH, volatile fatty acid, VFA) were studied by inoculum and feedstuffs. The feedstuffs, according to their chemical composition, showed very different fermentation characteristics. In particular, OMd, A and Rmax allowed feedstuff classification as follows: barley>beet pulp>alfalfa. The inocula differ (p<0.05) in Tmax, were higher for CI (15.53 vs. 11.96 h) and in VFA production. In particular, CI produced higher levels of acetate (38.9 vs. 33.4 mM/g OM incubated, p<0.01) and isobutyrate (0.72 vs. 0.42, p<0.01) but less propionate (7.1 vs. 10.3, p<0.01) and butyrate (11.3 vs. 14.0, p<0.01). However, the trend of gas production, similar for the inocula according to the fermented substrate, and the good regression equation to estimate some caecal fermentation parameters from faeces suggest that, after standardisation, the faeces could be used as an alternative inoculum for gas tests in rabbit.

• Journal of the Korea Concrete Institute
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• v.25 no.3
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• pp.347-354
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• 2013

Recently, crushed fine aggregates are being widely used due to the shortage of natural sand. In Korea, the amount of fine particles under 0.08 mm contained in crushed fine aggregates is restricted to be less than 7%, which is similar to the regulations of ASTM but is still very strict compared to the regulations of the other nations. In addition, the crushed aggregates already have in them about 20% of fine particles under 0.08 mm which occurs while they are crushed. The fine particles are not easy to wash out, and also to maximize the use of resources it is deemed necessary to review the possibility of enhancing the limit of the amount of fine particles. Therefore, this study conducted experiments to analyze the characteristics of fine particles under 0.08mm and their influence on the properties of concrete. Experiments using silt and cohesive soil were also done for comparison. In the experiments on fine particles, the methylene blue value was more in the soil dust contained in silt and cohesive soil than in the stone powder contained in crushed fine aggregates. Also, the methylene blue value had a close correlation with packing density and liquid & plastic limit. In the experiments done with concrete, the quantity of high range water reducing agent demanded to obtain the same slump increased as the fine particle substitution rate heightened. However, in the experiment which used stone powder testing the compressive strength and tensile strength of concrete in the same water-cement ratio, there was little change in strength with less than 20% addition of fine particles among the fine aggregates, and no meaningful difference in the amount of drying shrinkage of concrete.