• Bulletin of the Korean Mathematical Society
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• v.45 no.2
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• pp.231-239
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• 2008

We obtain a necessary and sufficient condition for the existence of Mendelsohn triple systems excluding contiguous units with ${\lambda}$ = 1. Also, we obtain the spectrum for cyclic such systems.

• Communications for Statistical Applications and Methods
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• v.23 no.6
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• pp.543-553
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• 2016

The validity of statistical inference depends on proper randomization methods. However, even with proper randomization, we can have imbalanced with respect to important characteristics. In this paper, we introduce a method based on ranked auxiliary variables for treatment allocation in crossover designs using Latin squares models. We evaluate the improvement of the efficiency in treatment comparisons using the proposed method. Our simulation study reveals that our proposed method provides a more powerful test compared to simple randomization with the same sample size. The proposed method is illustrated by conducting an experiment to compare two different concentrations of titanium dioxide nanofiber (TDNF) on rats for the purpose of comparing weight gain.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.2
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• pp.335-352
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• 2023

When solving multi-objective optimization problems, the blindness of the evolution direction of the population gradually emerges with the increase in the number of objectives, and there are also problems of convergence and diversity that are difficult to balance. The many- objective optimization problem makes some classic multi-objective optimization algorithms face challenges due to the huge objective space. The sine cosine algorithm is a new type of natural simulation optimization algorithm, which uses the sine and cosine mathematical model to solve the optimization problem. In this paper, a knee-driven many-objective sine-cosine algorithm (MaSCA-KD) is proposed. First, the Latin hypercube population initialization strategy is used to generate the initial population, in order to ensure that the population is evenly distributed in the decision space. Secondly, special points in the population, such as nadir point and knee points, are adopted to increase selection pressure and guide population evolution. In the process of environmental selection, the diversity of the population is promoted through diversity criteria. Through the above strategies, the balance of population convergence and diversity is achieved. Experimental research on the WFG series of benchmark problems shows that the MaSCA-KD algorithm has a certain degree of competitiveness compared with the existing algorithms. The algorithm has good performance and can be used as an alternative tool for many-objective optimization problems.

• International Journal of Fluid Machinery and Systems
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• v.9 no.3
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• pp.229-236
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• 2016

Exergetic analysis was introduced in optimization of a rotating equilateral triangular internal cooling channel with staggered square ribs to maximize the net exergy gain. The objective function was defined as the net exergy gain considering the exergy gain by heat transfer and exergy losses by friction and heat transfer process. The flow field and heat transfer in the channel were analysed using three-dimensional Reynolds-averaged Navier-Stokes equations under the uniform temperature condition. Shear stress transport turbulence model has been selected as a turbulence closure through the turbulence model test. Computational results for the area-averaged Nusselt number were validated compared to the experimental data. Three design variables, i.e., the angle of rib, the rib pitch-to-hydraulic diameter ratio and the rib width-to-hydraulic diameter ratio, were selected for the optimization. The optimization was performed at Reynolds number, 20,000. Twenty-two design points were selected by Latin hypercube sampling, and the values of the objective function were evaluated by the RANS analysis at these points. Through optimization, the objective function value was improved by 22.6% compared to that of the reference geometry. Effects of the Reynolds number, rotation number, and buoyancy parameter on the heat transfer performance of the optimum design were also discussed.

• Korean Journal of Agricultural Science
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• v.43 no.3
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• pp.379-386
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• 2016

Four ruminally cannulated Holstein steers (BW $482.9{\pm}8.10kg$), fed low protein TMR (CP 11.7%) as a basal diet, were used to investigate changes in rumen fermentation and blood metabolism according to protein fraction, cornell net carbohydrates and protein system (CNCPS), and enriched feeds. The steers, arranged in a $4{\times}4$ Latin square design, consumed TMR only (control), TMR supplemented with rapeseed meal (AB1), soybean meal (B2), and perilla meal (B3C), respectively. The protein feeds were substituted for 23.0% of CP in TMR. Ruminal pH, ammonia-N, and volatile fatty acids (VFA) in rumen digesta, sampled through ruminal cannula at 1 h-interval after the morning feeding, were analyzed. For plasma metabolites analysis, blood was sampled via the jugular vein after the rumen digesta sampling. Different N fraction-enriched protein feeds did not affect (p > 0.05) mean ruminal pH except AB1 being numerically lower 1 - 3 h post-feeding than the other groups. Mean ammonia-N was statistically (p < 0.05) higher for AB1 than for the other groups, but VFA did not differ among the groups. Blood urea nitrogen was statistically (p < 0.05) higher for B2 than for the other groups, which was rather unclear due to relatively low ruminal ammonia-N. This indicates that additional studies on relationships between dietary N fractions and ruminant metabolism according to different levels of CP in a basal diet should be required.

• Biomolecules & Therapeutics
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• v.6 no.3
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• pp.296-302
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• 1998

The bioequivalence of two cyclosporin A products was evaluated in 26 normal male volunteers (age 25 ~33 yr, body weight 56~84 kg) following single oral administration. Test product was a hard capsule containing the granule of cyclosporin A (Chong Kun Dang Corp., Korea) and reference product, Sandimmun", was a soft capsule containing surfactant, oil, alcohol and cyclosporin A (Sandoz, Swiss). Both products contain 100 mg of cyclosporin A. Four capsules of the test and the reference product were administered to the volunteers, respectively, by randomized two period cross-over study (2$\times$2 Latin square method). Average drug concentrations at each sampling time and pharmacokinetic parameters were not significantly different between two products (p>0.05); the area under the concentration-time curve to last sampling time (24 hr) (AU $Co_{24}$) (5034.8$\pm$ 1760.6 vs 4635.4$\pm$ 1158.9 ng . h/ml), maximum plasma concentration ( $C_{max}$) (1002.7$\pm$353.1 vs 980. 4$\pm$ 171.7 ng/71), and mean residence time (MRT) (6.16$\pm$0.81 vs 5.64$\pm$0.50 h). The differences of mean AUC 7-,4,7~, T_ and MRT between the two products (7.93,2.22,16 and 8.39%, respectively) were less than 20% given as a guideline. The power (1-$\beta$) and treatment difference ($\Delta$) for AU $Co_{24}$, $C_{max}$ and MRT were more than 0.8 and less than 0.2, respectively. Although $T_{max}$ of the two products was significantly different each other (p<0.05), $T_{max}$ might be an insignificant parameter because cyclosporin A generally requires long-term administration. From these results, the two products are bioequivalent.alent.t.

• Nuclear Engineering and Technology
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• v.21 no.1
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• pp.18-31
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• 1989

To analyze the impact of air pollution control on electricity generation cost, a computer program was developed. POGEN calculates levelized discounted power generation cost including additional air pollution control cost for coal power plant. Pollution subprogram calculates total capital and variable costs using governing equations for flue gas control. The costs are used as additional input for levelized discounted power generation cost subprogram. Pollution output for Rue Gas Desulphurization direct cost was verified using published cost data of well experienced industrialized countries. The power generation costs for the year 2001 were estimated by POGEN for three different regulatory scenarios imposed on coal power plant, and by levelized discounted power generation cost subprogram for nuclear power. Because of uncertainty expected in input variables for future plants, sensitivity and uncertainty analysis were made to check the importance and uncertainty propagation of the input variables using Latin Hypercube Sampling and Multiple Least Square method. Most sensitive parameter for levelized discounted power generation cost is discount rate for both nuclear and coal. The control cost for flue gas alone reaches additional 9-11 mills/kWh with standard deviation less than 1.3 mills/kWh. This cost will be nearly 20% of power generation cost and 40% of one GW capacity coal power plant investment cost. With 90% confidence, the generation cost of nuclear power plant will be 32.6-51.9 mills/kWh, and for the coal power plant it will be 45.5-50.5 mills/kWh. Nuclear is favorable with 95% confidence under stringent future regulatory requirement in Korea.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.9
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• pp.1065-1071
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• 2012

Wind energy is becoming one of the most preferable alternatives to conventional sources of electric power that rely on fossil fuels. For stable electric power generation, constant rotating speed control of a wind turbine is performed through pitch control and stall control of the turbine blades. Recently, variable pitch control has been implemented in modern wind turbines to harvest more energy at variable wind speeds that are even lower than the rated one. Although wind turbine pitch controllers are currently optimized using a step response via the Ziegler-Nichols auto-tuning process, this approach does not satisfy the requirements of variable pitch control. In this study, the variable pitch controller was optimized by a genetic algorithm using a neural network model that was constructed by the Latin Hypercube sampling method to improve the Ziegler-Nichols auto-tuning process. The optimized solution shows that the root mean square error, rise time, and settle time are respectively improved by more than 7.64%, 15.8%, and 15.3% compared with the corresponding initial solutions obtained by the Ziegler-Nichols auto-tuning process.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.7
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• pp.960-966
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• 2004

The purpose of this study was to evaluate the effects of protein supplementation of green tea waste (GTW) on the performance of lactating cows. Another aim was to increase resource utilization and to eliminate any environmental negative impact from the tea waste. GTW from a beverage company was ensiled at a low pH (<4.0) and high acetic acid and lactic acid concentration, and it contained high crude protein (CP, 34.8%), total extractable tannins (TET, 9.2%) and condensed tannin (CT, 1.7%). Two experiments were conducted to investigate the palatability and performance in lactating cows fed GTW. In the palatability trial, three lactating cows were allocated to three dietary treatments in a 3$\times$3 Latin square design. The animals were offered a total mixed ration (TMR) including GTW at rates of 0, 2.5 and 5.0% on a dry matter (DM) basis. Total DM intake was not different among the treatments. In the performance trial, four lactating cows were used in a 2$\times$2 Latin square design with a 3 week sampling period. GTW was incorporated into TMR at a rate of 5.0% on a DM and 10.0% on a CP basis. Thus GTW replaced alfalfa hay and soybean meal at a level of 25.0% on a DM. DM and CP intake were not affected by the inclusion of GTW, whereas TET and CT intake were significantly increased (p<0.001). Milk production, milk composition and the efficiency of milk production were not altered by the GTW inclusion. Although ruminal pH and VFA, and blood urea nitrogen were not changed, ruminal $NH_{3}-N$ and plasma total cholesterol were relatively low in the GTW group, but not significantly different. The excretion of urinary purine derivatives and estimated MN supply were also not significantly affected by GTW treatment. It is therefore concluded that GTW can be used as a protein source without any detrimental effects on the performance of lactating cows.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.12
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• pp.1746-1751
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• 2005

The objective of this study was to evaluate the effects of sarsaponin on methane production, ruminal fermentation, nutrient digestion and blood metabolites using three Holstein steers in a 3${\times}$3 Latin Square design. The steers were fed Sudangrass hay plus concentrate mixture at a ratio 1.5:1 twice daily, and sarsaponin (0, 0.5 and 1% of DM), which was given at 09:00 and 17:00 h daily by mixing with concentrate. Rumen samples were collected 0, 2, and 5 h after morning dosing. Ruminal pH was numerically decreased and numbers of protozoa were decreased linearly (p<0.01) by treatment. Ruminal ammonia-N was reduced (linear; p<0.05) and total VFA was increased (quadratic; p<0.05) at 2 and 5 h after sarsaponin dosing. The molar proportion of acetate was decreased (quadratic; p<0.05) and propionate was increased (linear; p<0.01) at all sampling times. Blood plasma glucose was increased and urea-N was decreased (linear; p<0.05) at 2 and 5 h after dosing. Methane was decreased by approximately 12.7% (linear; p<0.05). The apparent digestibility of DM and NDF were decreased (quadratic; p<0.05) and that of CP remained unchanged due to the sarsaponin. The numbers of cellulolytic bacteria were decreased (quadratic; p<0.05), while numbers of total viable bacteria remained unchanged due to the sarsaponin. These results show that sarsaponin can partially inhibit rumen methanogenesis in vivo and improve ruminal fermentation, which supports our previous in vitro results.