• Fisheries and Aquatic Sciences
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• v.2 no.1
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• pp.52-57
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• 1999

Air-drived rotating biological contactor (RBC) system, which is effective method in filtering performance, was tested for the nitrification capacity in a recirculating system. At ammonia concentrations between 0.029 and 0.528 mg/l, the effect of ammonia loading rate on ammonia removal rate at three different hydraulic loading rates could be defined by the following first­order regression models: Hydraulic loading rate of $14.8 m^3/m^3/day:\;y=39.2\times+3.4 (r^2=0.9137)$, Hydraulic loading rate of $26.5 m^3/m^3/day: y=53.3\times+4.0 (r^2=0.8686)$, Hydraulic loading rate of $37.3 m^3/m^3/day: y=58.4\times+4.2 (r^2=0.7755)$, where, $\times$ is ammonia loading rate (mg/l), y is ammonia removal rate $(g/m^3/day)$, The equations showed the optimal ammonia removal rate at the hydraulic loading rate of $26.5m^3/m^3/day$. Below the ammonia concentration of 2.72 mg/l, first-order regression models between ammonia loading rate and ammonia removal rate at three different rates of speed are defined as follows: Rotational speed of $0.75 rpm: y=28.5\times+4.7 (r^2=0.9143)$, Rotational speed of $1.0 rpm: y=33.6\times+8.4 (r^2=0.9534)$, Rotational speed of $2.0 rpm: y=28.9\times+3.6 (r^2=0.9488)$, where, x is ammonia loading rate (mg/l), y is ammonia removal rate $(g/m^3day)$. The equations show the ammonia removal rate at the rotational speed of 1.0 rpm is significantly higher than that at the rotational speed of either 0.75 rpm or 2.0 rpm (P<0.05).

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.6
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• pp.676-686
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• 2016

This study analyzed the long term relationship between the K-REITs' lending rate and interest rate variables based on ARDL (autoregressive distributed lag) and also examined the short term relationship based on the ARDL-ECM model. In the results of the empirical test, there is a co-integration relationship among the K-REITs' lending rate, 3 year government bond (rate), 3 year government bond (rate), corporation bond (rate) (AA-, 3year) and general fund loan rate. This means that the K-REITs' lending rate is related to the long term interest rate. The corporate general fund loan rate has a significant correlation with the K-REITs' lending rate in the long term relation and short term adjustment process. The establishment of a management plan by the REITs considering the trends in the corporate general fund loan rate in the decision making process for finance sector borrowings can be practically helpful for the K-REITs.

• Industry Promotion Research
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• v.1 no.1
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• pp.129-135
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• 2016

This study verified the water saving effect in case of raising water rate depends on water rate awareness. The study results showed that the perceived appropriacy of government aid(p<.001), home water rate(p<.01), water rate pricing system, water rate, water rate diffrences depend on use and area(p<.05) significantly affected the degree of agreement of raising water rate. Also, education, residence, member of household, occipation, monthly household income, monthly water rate significantly affected the degree of agreement of raising water rate, consumer behavior for saving water. This study provided implication for water rate pricing policy by analyzing the water saving effect in case of raising water rate depends on water rate awareness and revealing the determinants of the degree of agreement of raising water rate.

• International Area Studies Review
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• v.21 no.1
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• pp.181-200
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• 2017

This study investigates the impact of exchange rate and exchange rate volatility on the stock prices of eight industries from 2006 to 2015. The first and second exchange rate exposure of these eight industries is estimated with respect to four different exchange rates, namely the US dollar, Japanese yen, European currency unit, and British pound. In exchange rate exposure, stock prices in foods-beverages, paper-wood, electricity-gas, and banks industries are negatively related to exchange rate, whereas stock prices in electrical-electronic equp. and transport-equp. industries are positively related to exchange rate as expected. However stock price in machinery industry is negatively related to exchange rate, which is opposite to the expectation. Negative relationship is found between stock price in chemicals industry and exchange rate. In exchange rate volatility exposure, stock price in paper-wood industry is found to be negatively related to exchange rate volatility. Stock price in banks industry is also negatively related to exchange rate volatility. This result is opposite as expected, because banks are supposed to get more revenue by issuing derivatives related to foreign exchange when exchange rate volatility increases.

• Clinical and Experimental Reproductive Medicine
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• v.48 no.2
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• pp.174-183
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• 2021

Objective: The aim of this study was to compare the pregnancy outcomes of in vitro fertilization with embryo transfer between embryos cultured in a time-lapse monitoring system (TLS) and those cultured in a conventional incubator (CI). Methods: The medical records of 250 fertilized embryos from 141 patients undergoing infertility treatment with assisted reproductive technology at a tertiary hospital from June 2018 to May 2020 were reviewed. The study population was divided into TLS and CI groups at a 1 to 1 ratio (125 embryos per group). The primary outcome was the live birth rate. Results: The TLS group had a significantly higher clinical pregnancy rate (46.4% vs. 27.2%, p=0.002), implantation rate (27.1% vs. 12.0%, p=0.004), and live birth rate (32.0% vs. 18.4%, p=0.013) than the CI group. Furthermore, subgroup analyses of the clinical pregnancy rate and live birth rate in the different age groups favored the TLS group. However, this difference only reached statistical significance in the live birth rate in women aged over 40 years and the clinical pregnancy rate in women aged 35-40 years (p=0.048 and p=0.031, respectively). The miscarriage rate, cleavage rate, and blastocyst rate were comparable. Conclusion: TLS application improved the live birth rate, implantation rate, and clinical pregnancy rate, particularly in the advanced age group in this study, while the other reproductive outcomes were comparable. Large randomized controlled trials are needed to further explore the ramifications of these findings, especially in different age groups.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.06a
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• pp.215-216
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• 2007

• Journal of information and communication convergence engineering
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• v.14 no.3
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• pp.153-162
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• 2016

Microwave and millimeter waves are considered suitable frequency ranges for diverse applications. The prediction of rain attenuation required the 1-min rainfall rate distribution, particularly for data obtained locally from experimental measurement campaigns over a given location. Rainfall rate data acquired from Korea Meteorological Administration (KMA) for nine major sites are analyzed to investigate the statistical stability of the cumulative distribution of rainfall rate, as obtained from a 10-year measurement. In this study, we use the following rain rate conversion techniques: Segal, Burgueno et al., Chebil and Rahman, exponential, and proposed global coefficient methods. The performance of the proposed technique is tested against that of the existing rain rate conversion techniques. The nine sites considered for the average 1-min rain rate derivation are Gwangju, Daegu, Daejeon, Busan, Seogwipo, Seoul, Ulsan, Incheon, and Chuncheon. In this paper, we propose a conversion technique for a suitable estimation of the 1-min rainfall rate distribution.

• KSBB Journal
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• v.11 no.4
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• pp.476-480
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• 1996

Using Pseudomonas sp. B3, identified and isolated from nature, wastewater containing phenol was treated in a continuous stirred tank reactor and its reaction characteristics were studied. Average concentrations of phenol and COD in effluents were 1.5mg/L and 124mg/L at 0.059h-1 dilution rate, respectively. At the dilution rate higher than 0.063h-1, phenol and COD increased abruptly to 19mg/L and 318mg/L. At the dilution rate higher than 0.059h-1, biomass concentration suddenly decreased and was "washed out". Biomass concentration was 150mg/L at a dilution rate of 0.067h-1. Maximum biomass production rate was 15.98mg/L$.$h at a dilution rate of 0.067h-1. When dilution rate increased above 0.059h-1, effluent phenol concentration abruptly increased and biomass production rate decreased. Maximum cell growth rate(${\mu}$max) and Michaelis-Mentens kinetic constant(Ks) were 0.074h-1 and 0.424mg/L, respectively. From the above result low phenol concentration can be expected at a maximum dilution rate, but reactor becomes unstable due to phenol inhibition.

• Proceedings of the Korea Concrete Institute Conference
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• 1997.10a
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• pp.215-222
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• 1997

Flow experimental on not to be solid mortar which use Quenched Blast-furnace Slag as a fine aggregate was carried out for basic research data about fundamental study of application possibility of Quenched Blast-furnace Slag as a fine aggregate. It gives following result. The substitution rate is inversely proportional to Flow and C/S-rate same that. The relation with W/C-rate augment appear proportional : in case of C/S-rate, 1:3 increasing degree is a half of sand mortar that. Consequencely, Quenched Blast-furnace Slag motar is a counteraction to Flow in as same water content per unit. But suitable substitution rate and C/S-rate influence a little to the mortar consistency. And that reason, if C/S-rate and substitution rate will be regulated when we mix the mortar with quenched Blast-furnace Slag. that will be economic mixture.

• Structural Engineering and Mechanics
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• v.58 no.4
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• pp.719-729
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• 2016

The main objective of the present paper is to study the effect of the yield criterion on the magnitude of the strain rate and plastic work rate intensity factors in axisymmetric flow of isotropic incompressible rigid perfectly plastic material by means of a problem permitting a closed-form solution. The boundary value problem consisting of the axisymmetric deformation of a plastic tube is solved. The outer surface of the tube contracts. The radius of the inner surface does not change. The material of the tube obeys quite a general yield criterion and its associated flow rule. The maximum friction law is assumed at the inner surface of the tube. Therefore, the velocity field is singular near this surface. In particular, the strain rate and plastic work rate intensity factors are derived from the solution. It is shown that the strain rate intensity factor does not depend on the yield criterion but the plastic work rate intensity factor does.