• Advances in aircraft and spacecraft science
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• v.9 no.5
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• pp.401-414
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• 2022

In the present paper, the optimal selection of batteries for an electric pump-fed hybrid rocket engine is analyzed. A two-stage Mars Ascent Vehicle, suitable for the Mars Sample Return Mission, is considered as test case. A single engine is employed in the second stage, whereas the first stage uses a cluster of two engines. The initial mass of the launcher is equal to 500 kg and the same hybrid rocket engine is considered for both stages. Ragone plot-based correlations are embedded in the optimization process in order to chose the optimal values of specific energy and specific power, which minimize the battery mass ad hoc for the optimized engine design and ascent trajectory. Results show that a payload close to 100 kg is achievable considering the current commercial battery technology.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.758-761
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• 2004

This paper proposes a design and implementation of multiplierless digital PID (Proportional-Integral-Derivative) controller using FPGA (Field Programmable Gate Array) for controlling the speed of DC motor in digital system. The multiplierless PID structure is based on Distributed Arithmetic (DA). The DA is an efficient way to compute an inner product using partial products, each can be obtained by using look-up table. The PID controller is designed using MATLAB program to generate a set of coefficients associated with a desired controller characteristics. The controller coefficients are then included in VHDL (Very high speed integrated circuit Hardware Description Language) that implements the PID controller onto FPGA. MATLAB program is used to activate the PID controller, calculate and plot the time response of the control system. In addition, the hardware implementation uses VHDL and synthesis using FLEX10K Altera FPGA as target technology and use MAX+plusII program for overall development. Results in design are shown the speed performance and used area of FPGA. Finally, the experimental results can be shown when compared with the simulation results from MATLAB.

• Human Ecology Research
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• v.54 no.1
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• pp.13-26
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• 2016

The purpose of this paper is to investigate the rationale behind the transformation process of unique shophouse spatial organization in Phnom Penh. We selected 20 representative shophouses located in the Chinese district of Phnom Penh according to construction period. A qualitative study methodology was applied and field surveys were conducted that included interviews with residents, photographs, sketches, measurements, collecting historic photos, and cataloging maps. Selected cases were analyzed in terms of: basic house data, urban block analysis, and unit analysis. Cases were then classified into two types: private courtyard shophouse (PCS) and shared courtyard shophouse (SCS). PCS refers to shophouse typology that maintains most of the characteristics of early shophouses while being transformed into a modern multi-story apartment within a limited one bay plot. However, SCS refers to shophouses adapted from the indigenous forms of PCS that evolved into a multi-storey and multi-family housing typology that includes features that might have been adapted from Western apartment buildings such as sharing a big courtyard, staircase and corridors. We conclude that shophouses in Phnom Penh have positively adopted a Western building typology, adapted it to local traditions, and finally formulated a new building type that represent indicators of a modernization process gradually accepted by society.

• 한국생물공학회:학술대회논문집
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• 2003.10a
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• pp.351-355
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• 2003

Response surface methodology was employed to study the interactive effect of sucrose, nitrogen, temperature and to optimize their levels to enhance the production of human granulocyte-macrophage colony-stimulation factor from Nicotiana tabacum cell suspension cultures. A 15-runs Box-Behnken design including three center points was the response surface method selected for the initial set of experiments. The analysis of the data from the Box-Behnken experiments showed interactive effects of sucrose:nitrogen, sucrose:temperature and nitrogen:temperature. The optimal combinations of sucrose, nitrogen and temperature for hGM-CSF production from surface plot were sucrose 90 g/L, nitrogen 41 mM and 22$^{\circ}C$, respectively. The optimization of there factors enhanced the hGM-CSF production by 2 times because high sucrose concentration stimulated the secretion of hGM-CSF and low temperature prevented hGM-CSF degradation in media by pretenses.

• Korean journal of food and cookery science
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• v.23 no.4 s.100
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• pp.551-560
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• 2007

This study was performed to determine the optimum ratio of ingredients in the Sulgidduk with barley(Hordeum vulgare L.) sprout powder. A mathematical analytical tool was employed for optimization of the typical ingredients. The canonical form and trace plot showed the affect of each ingredient in the mixture against the final product. Mixture design showed 14 experimental points, including 4 replicates for three independent variables. The three independent variables selected for the experiment were: water($15{\sim}22%$), barley sprout powder($1{\sim}4%$), and sugar($12{\sim}19%$). The optimum responses variables such as color values(L, a, and b), instrumental texture parameters(hardness, gumminess, and chewiness), and sensory characteristics(appearance, color, smell, taste, softness, moistness, and overall acceptability) were evaluated. The Hunter colorimetric L- and a-values of the Sulgidduk decreased with an increasing amount of barley sprout powder. As more barley sprout powder was added, a higher b-value resulted. Textural hardness, gumminess, and chewiness were lowered by the addition of barley sprout powder. The optimum formulation obtained by both numerical and graphical methods showed similar results. The representative optimal ingredient ratio commonly obtained by both methods were: 18.2% water, 2.0% barley sprout powder, and 14.8% sugar.

• Journal of The Korean Society of Agricultural Engineers
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• v.49 no.3
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• pp.11-20
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• 2007

Estimation of crop consumptive use is a key term of agricultural water resource systems design and operation. The 10-year return period drought has special aspects as a reference period in design process of irrigation systems in terms of agricultural water demand analysis so that crop evapotranspiration (ETc) about the return period also has to be analyzed to assist understanding of crop water requirement of paddy rice. In this study, The ETc of 10-year return period drought was computed using frequency analysis by 54 meteorological stations. To find an optimal probability distribution, 8 types of probability distribution function were tested by three the goodness of fit tests including ${\chi}^2$(Chi-Square), K-S (Kolmogorov-Smirnov) and PPCC (Probability Plot Correlation Coefficient). Optimal probability distribution function was selected the 2-parameter Log-Normal (LN2) distribution function among 8 distribution functions. Using the two selected distribution functions, the ETc of 10-year return period drought was estimated for 54 meteorological stations and compared with prior study results suggested by other researchers.

• The Korean Journal of Applied Statistics
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• v.24 no.5
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• pp.893-904
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• 2011

The lecture of the experimental designs consists of two main part-experimental designs and model analysis. Mostly, the progress of the visualization has been made on a model analysis. As the visualization of experimental designs, we can consider the visualization of Latin squares, supersaturated designs, and balanced incomplete block designs. We can propose the design plots as well as use the scatterplots and the scatterplot matrices for the visualization of experimental designs. Through the visualization of experimental designs, we can use the synergy effect in teaching the lecture of the experimental designs.

• The Korean Journal of Food And Nutrition
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• v.27 no.2
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• pp.318-329
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• 2014

The purpose of this study was to determine the optimal mixing ratio of Allium hookeri powder and butter in the preparation of bread. The experiment was designed according to the central composite design for estimating the response surface, which demonstrated 10 experimental points, including 2 replicates for Allium hookeri powder and butter. Further, the mechanical and sensory properties of test materials were measured. A canonical form and perturbation plot conveyed the influence of each ingredient on the final product mixture. Overall, the measurement results of the mechanical properties showed a significant increase or decrease in dough pH, sweetness, volume, weight, height, specific volume, a & b-value of crumb and, springiness (p<0.05). Moreover, the sensory measurements demonstrated a significant improvement in color, appearance, texture, moistness and, overall quality. As a result, the optimum formulation from the numerical and graphical methods was calculated as 22.65 g of Allium hookeri powder and 47.77 g butter. After optimization, DPPH free radical scavenging activity, total phenolic content, and total plate counts over 10 days were evaluated. In sum, the results revealed the antioxidant and antibiotic actions of bread with Allium hookeri powder.

• Korean journal of food and cookery science
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• v.25 no.3
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• pp.337-344
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• 2009

The principal objective of this study was to determine the optimal mixing conditions of three different amounts of small black soybeans, sugar, and plain yogurt, for the preparation of a small black soybean smoothie. The experimental design utilized herein was based on the Central composite design methodology of response surface, which included 16 experimental points, including 2 replicates for the small black soybeans, sugar, and plain yogurt. The physiochemical and sensory properties of the test were measured, and these values were applied to the mathematical models. A canonical form and perturbation plot showed the influence of each ingredient on the mixed final product. The L value and a value decreased with increasing quantities of small black soybeans, but the b values increased with greater additions of small black soybeans. Sweetness increased with increasing amount of added sugar. The results of sensory evaluation showed very significant values for color (p<0.01), taste (p<0.05) and overall quality (p<0.05) in the predicted model. As a result, the optimum formulations by numerical and graphical methods were calculated as follows: small black soybean 79.46 g, plain yogurt 275.07 g, sugar 21.20 g.

• Journal of the Korean housing association
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• v.19 no.3
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• pp.49-58
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• 2008

This study focused on the architectural plan of the pension to meet modem people's desire for rural life, and the result of the study is as follows: First, the architectural plan for the characteristic of the location must apply the various architectural types considering the suburbs, tour and culture town, and community for the location improvement. Second, the architectural plan for the characteristic of the plot requires the encircled space and courtyard between buildings, the private gardens for the rooms, and the consideration of the surrounding environment. Above all, the plan for the subsidiary facilities is the most important. Third, the architectural plan for the characteristic of the plan requires the close connection with the outside, the wide opened view from the guest room, and the individual entrances for the guest rooms. Fourth, the architectural plan for the characteristic of the decorative design must consider the mass separation plan, the application of the facade design factors and eco-friendly environment materials, the night illumination plan, and the space program for the scenic view.