• Advances in concrete construction
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• 제14권3호
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• pp.215-225
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• 2022

Thermal comfort and energy conservation are critical issues in the building sector. Energy consumption in the building sector should be reduced whilst enhancing the thermal comfort of occupants. Concrete is the most widely used construction material in buildings. Its thermal conductivity (k-value) has a direct effect on thermal comfort perception. This study aims to find the optimum value of replacing the normal aggregate with lightweight expanded clay aggregate (LECA) under high strengths and low thermal conductivity, density and water absorption. The k-value of the LECA concrete and its physical and mechanical properties have varying correlations. Results indicate that the oven-dry density, compressive strength, splitting tensile strength and k-value of concrete decrease when normal coarse aggregates are replaced with LECA. However, water absorption (initial and final) increases. Thermal conductivity and the physical and mechanical properties have a strong correlation. The statistical optimisation of the experimental data shows that the 39% replacement of normal coarse aggregate by LECA is the optimum value for maximising the compressive and splitting tensile strengths whilst maintaining the k-value, density and water absorption at a minimum.

• Archives of Pharmacal Research
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• 제11권3호
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• pp.185-196
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• 1988

The inflence of hydrophilic vehicles on percutaneous absorption rate of griseofulvin was studied using intact skin of full thickness of hairless rat. The in vitro absorption rates were used as the characteristics for deciding the optimum formula of ointment vehicles. The optimum formula of vehicle compositions for maximum absorption rate was obtained from the polynomial regression equation and the two graphical techniques, contour graph and partial derivative graph. It was composed of sodium lauryl sulfate (1.65 W /W%), white petrolatum (16.5 W /W%), propylene glycol (12.0 W /W%), and stearyl alcohol (19.6W /W%). The experimental value obtained from the optimum formula and the prediction value were 33.99 and 33.87 ${\mu}g/\sqrt{min}$, respectively. From these results, it was believed that optimum formula for semisolid dosage forms could be obtained from the application of the optimization technique used in this study.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 춘계학술대회 논문집
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• pp.791-794
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• 2002

On this study, the dynamic response of vibration absorber was operated by finite element analysis and this paper proposed the optimum value of spring constant and damping coefficient for three types of impact absorber. Also the reaction farce of piston which is the objective function was proposed by the optimum design and the model which has the optimum value among the reaction forces was shown.

• KIEAE Journal
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• 제3권2호
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• pp.17-24
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• 2003

The purpose of this study is to present rational methods of multi-criteria optimization of the envelope of buildings. The object is to determine the optimum R-value of the envelope of a building, based on the following criteria: minimum building costs (including the cost of materials and construction) and yearly heating costs. Mathematical model described heat losses and gains in a building during the heating season. It takes into consideration heat losses through wall, roof, floor and windows. Particular attention was paid to have a more detailed description of heat gains due to solar radiation. On the assumption that shape of building is rectangle in order to solve the problem, optimum R-value of the envelope of a building is determined by using non-linear programing methods(Kuhn-Tucker Conditions). The results constitute information for designers on the optimum R-value of a building envelope for energy saving buildings.

• 한국환경과학회지
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• 제13권4호
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• pp.327-337
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• 2004

The education effect of environmental impact cognitive instruction on high school students was investigated. Environmental values of students could be classified into egocentric, social-altruistic and biospheric values like those of Schultz’s three kinds of categories. The value distribution of students consists 44.7% of egocentric and biospheric value groups and 12.5% of social-altruistic value group, respectively. The environmental function such as knowledge and skill did not show remarkable differences between value groups. The environmental value only affected the attitude function. The biospheric value group had the higher attitude function than other value groups. The environmental impact cognitive instruction enhanced the environmental functions irrespective of the value group or instruction type. However, significant variables were different according to environmental functions. Environmental functions such as knowledge and skill were influenced by the instruction itself. The attitude function was dependent on instruction itself, value type and instruction type. The optimum application of the environmental impact cognitive instruction can be efficiently achieved through class division into egocentric value group and biospheric value group. Alternatively, the proper combination of instruction methods focused biospheric and egocentric impacts in a class can be recommended.

• Communications for Statistical Applications and Methods
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• 제7권2호
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• pp.475-480
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• 2000

In a game called red and black, you can stake any amount is in your possession. Suppose your goal is 1 and your current fortune is $f$, with 0$p$ and lose your stake with probability, $q$=1-$p$. In this paper, we consider optimum strategies for this game with the value of $p$ less than $^1/_2$ where the house has the advantage over the player, and with the value of $p$ greater than $^1/_2$ where the player has the advantage over the house. The optimum strategy at any $f$ when $p$<$^1/_2$ is to play boldly, which is to bet as much as you can. The optimum strategy when $p$>$^1/_2$ is to bet $f\cdot\alpha$with $\alpha$, a sufficiently small number between 0 and 1.

• Structural Engineering and Mechanics
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• 제16권1호
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• pp.47-62
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• 2003

The nonlinear dependence aspect of various conical tool indentation parameters leading to an optimum tool semi angle value for easiest perforation is plotted and discussed explicitly in this work with the conclusion that tool angle has an optimum response towards most of the indentation parameters. Around this optimum angle, the aluminium sheets showed minimum fracture toughness as well as minimum work input to overcome the offered resistance. At the end, the mechanism leading to this phenomenon is presented with the conclusion that plastic flow dominates as the dimple semi cone angle reaches 35 and both pre and post plastic flow perforations lead the tool semi cone angle value towards this dimple cone semi angle of plastic flow initiation for its optimum performance. It is also concluded that specimen material failure is solely under tensile hoop stress and hence results into radial cracks initiation and propagation.

• 설비공학논문집
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• 제15권4호
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• pp.329-335
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• 2003

This study is on a experiment which shows to defrost automatically on the optimum time regardless of defrosting method. The result shows that the more defrost layers increase in fin tubes of evaporation, the less the section of the circulating air reduce. Thickness of the frost formation increases, so a pressure difference of ventilation increase, as a result automatic defrosting system sets the time COP drops suddenly up optimum time. Automatical defrosting system can find out the initial related current of evaporator fan motor and the value of load current in the optimum time. And it sets defrosting time, evaporating temperature, and temperature in refrigerator up system requiring value. Consequence of this experiment is that energy consumption with defrost load gets effect of reduction of eleven percent per 25.4 hours compared with common defrosting.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1998년도 춘계학술대회논문집
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• pp.237-241
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• 1998

This study is concerned with the optimum blank design which is able to minimize earing phenomena. A new analytic method is proposed to determine the optimum blank shape only using the tension test and standard deep drawing tests. Introducing a dimensionless parameter related to the earing and using a Fourier analysis, the optimum blank shape can be obtained by R-value and the tested results. The theoretical results by the proposed method are good agreement with the experimental results through several deep drawing tests using steel as working materials.

• Journal of Pharmaceutical Investigation
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• 제20권2호
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• pp.55-64
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• 1990

Soybean fatty acid, the largest byproduct in the production of soybean oil, was formulated for hand cream, oil in water emulsion base, to improve the suppleness and elasticity of skin. The stability of emulsion observed by a macroscopic method was used as a characteristic index for deciding an optimum formula of hand creams. The optimum formula of the most stable hand cream was obtained from polynomial regression equation, contour graphs and partial derivative graphs. The values of soybean fatty acid and stearyl alcohol in the obtained optimum formula were 9.75 and 14.75 w/w%, respectively, and sodium lauryl sulfate was not needed. Experimental value for the stability of hand cream prepared according to the optimum formula was 76,14 days, and the prediction value by computation method was 73.25 days. From the results of accelerated tests by elevated temperature, the stability of hand cream by optimum formula was 1.7 year at room temperature $(25^{\circ}C)$. The hand cream containing soybean fatty acid was found to be free of primary irritant substance to the skin by Draize technique.