• Asian-Australasian Journal of Animal Sciences
• /
• v.13 no.12
• /
• pp.1731-1737
• /
• 2000

This study was conducted to investigate the effects of threonine:lysine ratios on growth performance, apparent nutrient digestibility and blood urea nitrogen (BUN) concentration, and to estimate the optimal threonine:lysine ratios for growing barrows and gilts. A total of 150 pigs (Landrace${\times}$Yorkshire${\times}$Duroc, $16.75{\pm}0.42kg$ average body weight, 75 barrows and 75 gilts) was randomly allotted into six treatments in a $2{\times}3$ factorial design. Six diets were formulated to contain 1.12% lysine for barrows and 1.33% lysine for gilts with three threonine:lysine ratios (50, 60 and 70%) for both barrows and gilts. Throughout the whole experimental period (16 to 56 kg body weight), there was no interaction between sex and dietary threonine:lysine ratio in average daily gain (ADG), average daily feed intake (ADFI) and feed conversion rate (FCR). Between sexes, there was a clear sex-effect showing better growth performance of barrows. Barrows consumed more feed (p<0.01) and grew faster (p<0.01) than gilts. For barrows, there was a trend to improved ADG and FCR with increasing threonine:lysine ratio. For gilts, there was a trend to improved ADG and FCR up to threonine:lysine ratio of 60%, but not significant. There was no interaction between sex and threonine:lysine ratio in nutrient digestibilities of growing pigs except for crude ash (CA). Between sexes, there were differences in nutrient digestibilities, except for calcium for which gilts showed higher a digestibility (p<0.01). Among dietary threonine:lysine ratios, there were no differences in nutrient digestibilities. Mean values of essential amino acids (EAA), non-essential amino acids (NEAA) and total amino acids (TAA) digestibilities were not affected by sex and dietary threonine:lysine ratio. There was no evidence of an interaction between sexes and dietary threonine:lysine ratio. Between sexes, total BUN concentration was lower in gilts than barrows (p<0.05). It was concluded that a 70 and 60% dietary threonine:lysine ratio for barrows (1.12% lysine) and gilts (1.33% lysine) tended to result in better growth performances and nutrient utilization and lower BUN concentration than other threonine:lysine ratios.

• Journal of Ginseng Research
• /
• v.33 no.2
• /
• pp.143-148
• /
• 2009

This study was carried out to detennine the optimal submerged culture conditions for the growth increase of ginseng adventitious roots containing germanium by means of a fractional factorial design with four factors and three levels, using the response surface methodology (RSM). The ginseng (Panax ginseng CA. Meyer) adventitious roots were induced by plant growth regulators and cultured in a liquid SH medium. The effects of various $GeO_2$ and phosphoric acid ($H_3P0_4$) concentrations in the medium, $GeO_2$ addition time and the pH of the medium on the fresh weight of the ginseng adventitious roots were investigated. The optimum pH of the medium and the phosphoric acid concentration detennined by the partial differentiation of the model equation were 4.7 and 6.0 roM, respectively. The predicted optimal $GeO_2$ concentration was 10 ppm and the $GeO_2$ addition time did not affect the growth of ginseng adventitious roots. Under these conditions, the growth of the ginseng adventitious root containing germanium was predicted to be 2.47 g.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.34 no.5
• /
• pp.263-270
• /
• 2021

In this study, a reliability-based design optimization of a 130-m class fixed-type offshore platform, to be installed in the North Sea, was carried out, while considering environmental, material, and manufacturing uncertainties to enhance its structural safety and economic aspects. For the reliability analysis, and reliability-based design optimization of the structural integrity, unity check values (defined as the ratio between working and allowable stress, for axial, bending, and shear stresses), of the members of the offshore platform were considered as constraints. Weight of the supporting jacket structure was minimized to reduce the manufacturing cost of the offshore platform. Statistical characteristics of uncertainties were defined based on observed and measured data references. Reliability analysis and reliability-based design optimization of a jacket-type offshore structure were computationally burdensome due to the large number of members; therefore, we suggested a method for variable screening, based on the importance of their output responses, to reduce the dimension of the problem. Furthermore, a deterministic design optimization was carried out prior to the reliability-based design optimization, to improve overall computational efficiency. Finally, the optimal design obtained was compared with the conventional rule-based offshore platform design in terms of safety and cost.

• Food Science and Preservation
• /
• v.20 no.6
• /
• pp.810-817
• /
• 2013

This study investigated the properties of rice snack puffed in a microwave oven after drying its dough according to Baekjinju soaking time and additional soybean milk. The optimum conditions for the non-fried rice snack using Baekjinju wetted flour were determined through the design of an experiment using response surface methodology. The independent variables were the Baekjinju soaking time and the additional soybean milk, and the dependent variables were the weight, volume, density, expansibility, Hunter's color value, hardness, and sensory properties. The quadratic model was chosen for the weight, density, expansibility, b value, and hardness. The two-factor interaction model was chosen for the volume, flavor, appearance, and overall preference. The linear model was chosen for the L value, taste, and texture. The weight was increased to longer than 11.26 days with the increase in the rice soaking. The volume, expansibility, L value, and b value increased with the increase in the rice soaking time and in the additional soybean milk ratio. However, the density was decreased was in reverse. The hardness increased most, with the rice soaking time rising from 5.28 to 8.53 days and the soybean milk additional ratio increasing from 5.34 to 20.26%. The sensory properties improved as rice soaking time decreased, and the soybean milk additional ratio was revered. As for the desirability, the optimal formulation of the dough of non-fried rice snack was achieved by mixing 200 g of Baekjinju flour with a 0.69 days rice soaking time and a 26.67% soybean milk of rice ratio according to weight.

• Animal Bioscience
• /
• v.35 no.12
• /
• pp.1948-1956
• /
• 2022

Objective: This study was conducted to evaluate the effects of selenium (Se) source and level on the physiological response, reproductive performance, serum Se level, and milk composition in gestating sows. Methods: A total of 54 multiparous sows (Yorkshire×Landrace) with average body weight (BW), backfat thickness (BF), and parity were assigned to one of five treatments with 10 or 11 sows per treatment using a 2×2 factorial arrangement with one additional treatment in a completely randomized design. Inorganic or organic Se (IS or OS) sources were added to the diet at 0.30 ppm and 0.50 ppm Se. A non-Se-fortified corn-soybean meal basal diet served as a negative control. Treatments were as follows: i) Control: corn-soybean based diet, ii) IS30: control+inorganic Se 0.30 ppm, iii) IS50: control+inorganic Se 0.50 ppm, iv) OS30: control+ organic Se ppm, and v) OS50: control+organic Se 0.50 ppm. Results: At day 21 of lactation, piglet weight and weight gain in the OS treatments were higher than those in the IS treatments (p<0.05). Meanwhile, adding 0.5 ppm Se also resulted in the same significant differences in piglet BW and weight gain (p<0.05). Colostrum and milk Se concentrations increased (p<0.05) with Se level for both Se sources but were greater when sows were fed organic Se (p<0.05). Except for 24 hours postpartum, the Se concentrations were higher when sows were fed organic Se (p<0.05). Sow serum Se content was greater as Se levels increased from 0.3 ppm to 0.5 ppm at day 110 of gestation, 24 hours postpartum and day 21 of lactation (p<0.05). The pig serum Se concentration increased as the dietary Se level increased (p<0.05) and was higher when the sow dietary Se source was organic (p<0.05). Organic Se 0.5 ppm also had the highest serum Se level at two measured points (p<0.05). Conclusion: Consequently, supplementation with organic Se or 0.5 ppm Se in a gestating diet could improve piglet performance, the Se status of sows and piglets and milk composition, but organic Se at 0.5 ppm is optimal.

• Journal of the Korean Society for Railway
• /
• v.19 no.4
• /
• pp.515-525
• /
• 2016

Parameter analysis of a pretension girder bridge for urban maglev transit was performed to identify the main design parameters and their effect. Girder deflection at mid-span is the most important design criteria of urban maglev transit. Therefore, concrete compressive strength, girder height, girder length, and unbonded tendon length were selected as the design parameters that relate to girder deflection. In addition, tendon layout and unbonded tendon ratios were also considered as design parameters to control the top stress of the pretension girder section at the support. The analysis results show that both the girder height and length are dominant design parameters governing girder deflection, more important than compressive strength and unbounded tendon length. And, sensitivity analysis makes this study suggest design weight value. In terms of stress, a tendon layout that can satisfy the unbounded tendon rule requires an additional tendon or rebar at the upper section to control the tensile stress on top of the section. Therefore, to improve feasibility and constructability in the future, an enhanced unbonded tendon rule considering the load characteristics of the urban maglev system should be studied.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.29 no.6
• /
• pp.555-562
• /
• 2016

Seismic design of braced frames that simultaneously considers economic issues and structural performance represents a rather complicated engineering problem, and therefore, a systematic and well-established methodology is needed. This study proposes a multi-objective seismic design method for an inverted V-braced frame with suspended zipper struts that uses the non-dominated sorting genetic algorithm-II(NSGA-II). The structural weight and the maximum inter-story drift ratio as the objective functions are simultaneously minimized to optimize the cost and seismic performance of the structure. To investigate which of strength- and performance-based design criteria for braced frames is the critical design condition, the constraint conditions on the two design methods are simultaneously considered (i.e. the constraint conditions based on the strength and plastic deformation of members). The linear static analysis method and the nonlinear static analysis method are adopted to check the strength- and plastic deformation-based design constraints, respectively. The proposed optimal method are applied to three- and six-story steel frame examples, and the solutions improved for the considered objective functions were found.

• Journal of Korean Society of Steel Construction
• /
• v.17 no.6 s.79
• /
• pp.661-672
• /
• 2005

For the efficient stochastic optimization of steel structures for which a large number of analyses is required, artificial neural networks,which have emerged as a powerful tool that could have been used to replace time-consuming procedures in many scientific or engineering applications, are applied. They are utilized for the solution of the equilibrium equations resulting from the application of the finite element method in connection with the reanalysis type of problem, for which a large number of finite element analyses are required in this study. As such, the use of artificial neural networks to predict finite element analysis outputs simplifies and facilitates the performance of the stochastic optimal design of structural systems where a trained neural network is used to replace the structural reanalysis phase. Moreover, to improve efficiency of used artificial neural networks, genetic algorithm is utilized. The stochastic optimizer used in this study is an algorithm based on the evolution theory. The efficiency of the proposed procedure is examined in problems with both volume (weight) functions and real-world cost functions

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.43 no.4
• /
• pp.326-333
• /
• 2015

A turbo fan engine performance analysis program combined with a particle swarm optimization(PSO) has been developed to optimize the major design parameters of the combat aircraft gas turbine engine. The optimized parameters includes bypass ratio, fan pressure ratio, high pressure compression ratio and burner exit temperature. The objective parameters have been determined using a multi-objective function consisting of the net thrust and specific fuel consumption along a weight function. The basic model for the combat aircraft gas turbine engine has been selected as the F404 turbofan engine which is widely used in the combat aircraft, F-18 and Korean high level training aircraft, T-50. The optimal conditions of four parameters have been obtained for various design conditions.

• Composites Research
• /
• v.29 no.6
• /
• pp.369-374
• /
• 2016

In this study, a structural optimal design of 10 MW composite blade was performed using bend-twist coupled(BTC) design concept. Bend-twist coupling of blade means the coupling behavior between the bending and torsional deflections due to the composite lamina with fiber angle biased from the blade longitudinal axis. This can potentially improve the overall performance of composite blade and reduce the dynamic loading. Parametric studies on layup angle, thickness and area of off-axis carbon UD were conducted to find the optimum coupling effect with weight reduction. Comparing the results of fatigue load analysis between conventional model and BTC applied model, the damage equivalent load(DEL) of blade root area were decreased about 3% in BTC model. To verify the BTC effect experimentally, a 1:29 scaled model was fabricated and the torsion at the tip under deflection behavior of blade stiffener model was measured by static load test.