• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.05a
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• pp.71-72
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• 2017

The oyster shell is lightweight and exhibits strength characteristics similar to sand. In this study, mortar specimens were fabricated by crushing them and processed to 5mm or less of the fine aggregate standard, and examined the fire resistance of the mortar according to changes in particle size distribution. In this experiment, seven particle size distribution conditions were tested. In addition, the mixing ratio was fixed at 1: 3, and the experiment was conducted in terms of the volume ratio because the densities of sand and oyster shells were different.

• Journal of the Korean Geographical Society
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• v.41 no.2 s.113
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• pp.212-226
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• 2006

Surface data generally represent continuous distribution of geographical or social phenomena of a region in urban analysis. Instances include distribution of temperature, population of region, and various distributions related to human activities. When spatial data are given in the form of surface, surface comparison is required as a way of comprehending the surface change or the relationship between two surfaces. As for previous approaches of surface comparison, there are visualization, quantitative methods and qualitative method. All those approaches, however, show the difference between two surfaces in a limited way. Especially, they are not able to distinguish spatial difference between two surfaces. To overcome such problem, this paper proposes a method of comparing two surfaces in terms of their spatial structure. Main concept of the method comes from earth moving problem and the method is named minimum surface transformation, here. When a surface is transformed into another, total surface volume moved in the process of transformation should be the minimum. Both quantitative and spatial differences between two surfaces are evaluted by total surface volume moved and the distribution of moved surface volume of each cell respectively. The method is applied to hypothetical and actual data. From the former, it is understood that the method explains how two surfaces are quantitatively and spatially different. The result of the latter shows that moved total surface volume decreases as time goes by which fits the actual situation that population change rate gets smaller. Concerning the other measure of surface difference, the distribution of $X_{ij}$ describes detailed flow of surface volume than that of simply subtracting surface volume by indicating to what direction the population change occurs.

• International Journal of Fluid Machinery and Systems
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• v.2 no.1
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• pp.21-30
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• 2009

Slurry wear with sand particles in rivers is a serious problem for pump operation. Therefore, a technique to predict wear volume loss is required for selecting wear resistant materials and determining specifications for the maintenance period. This paper reports a method for predicting the wear depth distribution on the blade of an impeller. Slurry wear tests of an aluminum pump impeller were conducted. Prediction results of wear depth distribution approximately correspond with the results of slurry wear tests. This technique is useful for industrial application.

• Biomolecules & Therapeutics
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• v.1 no.2
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• pp.204-210
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• 1993

The distribution and excretion of DWC-751, a new cephalosporin, were examined in rats and mice following a single intravenous administration. DWC-751 in plasma and urine was determined by both HPLC and microbiological assay. The plasma concentration of the drug declined biexponentially. The initial and terminal half lives of the drug were 3.0 and 28.3 min, respectively. Binding of the drug to plasma proteins was 42.3%. The distribution volume at steacly-state ($Vd_{ss}$) was only 0.341 ι/kg, which is well correlated with the low n-octanol/water partition coefficient of the drug ($K_{o/w{\cong}0$) Actually, the drug was distributed to liver, kidney and lung with very low organ/plasma concentration ratio. The drug, was excreted mainly via renal excretion, i.e., the total($CL_T$) and apparent renal($CL_{R}$) clearances of the drug were 10.8 and 7.5 ml/min/kg, respectively.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.7 no.3
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• pp.382-395
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• 1995

A numerical study has been performed on flow characteristics in a domestic refrigerator whose size is $540mm{\times}1,530mm{\times}680mm$, considering existence of a fan and evaporator. The flow field has been simulated with the low Reynolds number $k-\bar{\varepsilon}$ turbulent model and SIMPLE algorithm based on the finite volume method. The region of fan which makes driving force for cold air distribution was modeled as a region in which momentum sources are generated uniformly. The concept of the distributed pressure resistance was applied to describe the momentum loss from evaporator. The result showed that the rate of cold air distribution into freezing room and cold storage room was almost 7 : 3.

• 한국연소학회:학술대회논문집
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• 2012.11a
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• pp.129-132
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• 2012

Computation is performed to predict number density, volume fraction and size distribution of soot particles in typical operating conditions of a diesel engine. KIVA has been integrated with the CMC routine to consider turbulence/chemistry coupling and gas phase kinetics for heat release and soot precursors. The compositions of soot precursors are estimated by tracking Lagrangian particles to consider spatial inhomogeneity and differential diffusion in KIVA. The soot simulator SWEEP is employed as a postprocessing step to calculate conditional and integral quantities of soot particles.

• Journal of Distribution Science
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• v.13 no.8
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• pp.5-14
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• 2015

Purpose - This study undertakes to examine the automotive trade structure between Korea and Russia to accelerate economic cooperation and pinpoint trade discrepancies to increase trade volume through improved policies, eventually finding ways for trade expansion. Research design, data, and methodology - To analyze trade decision factors for both countries, the Index of trade specialization invented by trade specialization theory, is used. Although specific factors should materialize in the trade decision analysis, realistically, concrete explanations are difficult as many unsolved factors are involved as well as their complexities Results - First, to assess comparative market competitiveness, the Index describes A value/B value, representing the Korean versus the Russia market share and the Korean market share versus the world. Second, the index shows that Korea is taking comparative advantage of its export specialization. Third, the RCA indices show considerable improvement compared to 2000. Conclusions - This research used a quantitative approach to examine trade specialization and examined a comparative advantage index of market share to see how inter-trade relations have changed over the past 10 years.

• Proceeding of KASS Symposium
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• 2006.05a
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• pp.191-204
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• 2006

This paper investigate the optimum thickness distribution of plate structure with different essential boundary conditions in the fundamental natural frequency maximization problem. In this study, the fundamental natural frequency is considered as the objective function to be maximized and the initial volume of structures is used as the constraint function. The computer-aided geometric design (CAGD) such as Coon's patch representation is used to represent the thickness distribution of plates. A reliable degenerated shell finite element is adopted calculate the accurate fundamental natural frequency of the plates. Robust optimization algorithms implemented in the optimizer DoT are adopted to search optimum thickness values during the optimization iteration. Finally, the optimum thickness distribution with respect to different boundary condition

• Proceeding of KASS Symposium
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• 2006.05a
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• pp.227-232
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• 2006

This paper investigate the optimum thickness distribution of plate structure with different essential boundary conditions in the fundamental natural frequency maximization problem. In this study, the fundamental natural frequency is considered as the objective function to be maximized and the initial volume of structures is used as the constraint function. The computer-aided geometric design (CAGD) such as Coon's patch representation is used to represent the thickness distribution of plates. A reliable degenerated shell finite element is adopted calculate the accurate fundamental natural frequency of the plates. Robust optimization algorithms implemented in the optimizer DoT are adopted to search optimum thickness values during the optimization iteration. Finally, the optimum thickness distribution with respect to different boundary condition

• Progress in Medical Physics
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• v.26 no.4
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• pp.208-214
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• 2015

The aim of this study is to investigate the effect of low magnetic field on dose distribution in the partial-breast irradiation (PBI). Eleven patients with an invasive early-stage breast carcinoma were treated prospectively with PBI using 38.5 Gy delivered in 10 fractions using the $ViewRay^{(R)}$ system. For each of the treatment plans, dose distribution was calculated with magnetic field and without magnetic field, and the difference between dose and volume for each organ were evaluated. For planning target volume (PTV), the analysis included the point minimum ($D_{min}$), maximum, mean dose ($D_{mean}$) and volume receiving at least 90% ($V_{90%}$), 95% ($V_{95%}$) and 107% ($V_{107%}$) of the prescribed dose, respectively. For organs at risk (OARs), the ipsilateral lung was analyzed with $D_{mean}$ and the volume receiving 20 Gy ($V_{20\;Gy}$), and the contralateral lung was analyzed with only $D_{mean}$. The heart was analyzed with $D_{mean}$, $D_{max}$, and $V_{20\;Gy}$, and both inner and outer shells were analyzed with the point $D_{min}$, $D_{max}$ and $D_{mean}$, respectively. For PTV, the effect of low magnetic field on dose distribution showed a difference of up to 2% for volume change and 4 Gy for dose. In OARs analysis, the significant effect of the magnetic field was not observed. Despite small deviation values, the average difference of mean dose values showed significant difference (p<0.001), but there was no difference of point minimum dose values in both sehll structures. The largest deviation for the average difference of $D_{max}$ in the outer shell structure was $5.0{\pm}10.5Gy$ (p=0.148). The effect of low magnetic field of 0.35 T on dose deposition by a Co-60 beam was not significantly observed within the body for PBI IMRT plans. The dose deposition was only appreciable outside the body, where a dose build-up due to contaminated electrons generated in the treatment head and scattered electrons formed near the body surface.