• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.12
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• pp.1079-1088
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• 2015

Parallelism and performance enhancement of calculating view factors in KSDS developed by KARI is introduced in this paper. View factor is an essential parameters of radiation thermal analysis for a spacecraft, and the amount of computation of them is not negligible. Especially, independent integration of view factors at each position of the orbit because the relative displace between solar panel and main body of a satellite varies with the position on the orbit. This paper introduces a range of parallelism of computing view factor and their performance, detection of obstructions by spatial search algorithm based on KD-Tree, and the reduction of the calculation of view factors of a satellite with relative motion between solar panel and main body, called updating fractional view factor matrix, for satellite thermal analysis.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.22 no.4
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• pp.339-347
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• 2004

This study aims at calculating the exact soil conversion factor of cutting and banking areas of weathering rocks in large-scaled construction sites where land is being developed into home lots. For this, we have excavated the respective 20 sites of the cutting and banking areas in the said site and then calculated the volume after the excavation. As a result, the relative accuracy of the difference was calculated at 0.5% in average. We have calculated the exact soil conversion factor by the use of function ratio as per the wet unit weight and the indoor soil quality test as per volume calculated. And then we have found out minor differences as a result of the comparison and analysis with soil conversion factor determined by the dry unit weight test as per sand replacement method. This may be judged as a rational design method for the calculation of soil conversion factor, as well as high reliability of site test as a precision photogrammetry is adopted for volume measurement of the irregular excavating areas.

• Korean Journal of Agricultural and Forest Meteorology
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• v.14 no.4
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• pp.269-276
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• 2012

The objective of this short communication is to introduce several evaluation methods to crop model users because the evaluation of crop model performance is an important step to develop or select crop model. In this paper, mean error, mean absolute error, index of agreement, root mean square error, efficiency of model, accuracy factor and bias factor were explained and compared in terms of dimension and observed number. Efficiency of model and index of agreement are dimensionless and independent of number of observation. Relative root mean square, accuracy factor and bias factor are dimensionless and not independent of number of observation. Mean error and mean absolute error are affected by dimension and number of observation.

• Asian-Australasian Journal of Animal Sciences
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• v.9 no.6
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• pp.695-699
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• 1996

This experiment was to determine the effect of sialoadenectomy on the ability of the mammary gland development to response to ovarian steroids, estrogen and progesterone, stimulus in vivo. Body weights did not differ between sham-operated and sialoadenectomized mice within 0 to 18 day estradiol + progesterone (E + P) injection (p > 0.05). Sialoadenectomy reduced mammary development scores from 4.6 to 3.9 or from 4.4 to 3.8 in comparison with those of sham-operated mice for the 12 or 18 day E + P injection ($P{\leq}0.05$), however, sialoadenectomized mice with 0, 1, 3 or 6 day of E + P injection slightly decreased mammary development scores relative to those of sham-operated mice. These results indicate that the endocrine factor secreted from submandibular salivary gland appears to be required for the mammary development to respond fully to estradiol and progesterone. Similar results were obtained in the measurement of mammary DNA contents. Mammary DNA contents of sialoadenectomized mice were significantly decreased relative to those of sham-operated mice for the 6, 12 or 18 day E + P injections. Overall results suggest that salivary gland-secreted endocrine factor, presumably epidermal growth factor (EGF), was mammogenic and should interact with ovarian steroids in mammary development.

• Journal of The Korean Astronomical Society
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• v.51 no.4
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• pp.111-117
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• 2018

A numerical method is proposed to calculate the response of detectors measuring particle energies from incident isotropic fluxes of electrons and positive ions. The isotropic flux is generated by injecting particles moving radially inward on a hypothetical, spherical surface encompassing the detectors. A geometric projection of the field-of-view from the detectors onto the spherical surface allows for the identification of initial positions and momenta corresponding to the clear field-of-view of the detectors. The contamination of detector responses by particles penetrating through, or scattering off, the structure is also similarly identified by tracing the initial positions and momenta of the detected particles. The relative contribution from the contaminating particles is calculated using GEANT4 to obtain the geometric factor of the instrument as a function of the energy. This calculation clearly shows that the geometric factor is a strong function of incident particle energies. The current investigation provides a simple and decisive method to analyze the instrument geometric factor, which is a complicated function of contributions from the anticipated field-of-view particles, together with penetrating or scattered particles.

• Human Ecology Research
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• v.53 no.1
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• pp.1-16
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• 2015

This study aims to examine the effects of high school students' time management behaviors on their satisfaction with educational consumption and school life. Three hundred seventy-six high school students in Seoul participated in this investigation. The SPSS ver. 19.0 program was adopted for the descriptive analysis, factor analysis, Cronbach's ${\alpha}$, and multiple regression analysis. The results of the present study can be summarized as follows: first, the levels of time management behavior, satisfaction with educational consumption at school, and satisfaction with school life were relatively high. Second, an analysis of the relative influence on satisfaction with educational consumption revealed that the students' time management behavior was the most influential factor, followed by academic achievement. As the levels of time management behavior and academic achievement were high, the level of satisfaction with educational consumption was high. Finally, an analysis of the relative influence of satisfaction with school life also revealed that the students' time management behavior was the most influential factor, followed by academic achievement. Based on the findings, that is, the effects of high school students' time management behavior and other involved variables on their satisfaction with educational consumption and school life, a future study can present specific ways to enhance the level of satisfaction with educational consumption and school life.

• Nuclear Engineering and Technology
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• v.48 no.5
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• pp.1126-1139
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• 2016

In this research, for the first time, a new optimization method, i.e., strength Pareto evolutionary algorithm II (SPEA-II), is developed for the burnable poison placement (BPP) optimization of a nuclear reactor core. In the BPP problem, an optimized placement map of fuel assemblies with burnable poison is searched for a given core loading pattern according to defined objectives. In this work, SPEA-II coupled with a nodal expansion code is used for solving the BPP problem of Kraftwerk Union AG (KWU) pressurized water reactor. Our optimization goal for the BPP is to achieve a greater multiplication factor ($K_{eff}$) for gaining possible longer operation cycles along with more flattening of fuel assembly relative power distribution, considering a safety constraint on the radial power peaking factor. For appraising the proposed methodology, the basic approach, i.e., SPEA, is also developed in order to compare obtained results. In general, results reveal the acceptance performance and high strength of SPEA, particularly its new version, i.e., SPEA-II, in achieving a semioptimized loading pattern for the BPP optimization of KWU pressurized water reactor.

• The KSFM Journal of Fluid Machinery
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• v.2 no.3 s.4
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• pp.52-58
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• 1999

The leakage and rotordynamic coefficients of see-through type gas labyrinth seals are determined using a two-control-volume-model analysis with Moody's wall-friction-factor formula which is defined with a large range of Reynolds number and relative roughness. Jet flow theory are used for the calculation of the recirculation velocity in the cavity. For the reaction force from the labyrinth seal, linearized zeroth-order and the first-order perturbation equations are developed for small motion about a centered position. The leakage and rotordynamic coefficient results of the present analysis are compared with Scharrer's theoretical analysis using Blasius' wall-friction-factor formula and Pelletti's experimental results. The comparison shows that the present analysis using Moody's wall-friction-factor formula and Scharrer's theoretical analysis using Blasius' wall-friction-factor formula give the same results for a smooth seal surface and the range of Reynolds number less than $10^5$.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.720-723
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• 2006

This study performed slope stability analysis by changing analysis methods and shear strength with the slope stability analysis program. The conclusions of the study are as follows. 1) The safe factor of clayey soil applied with Bishop's simple method turned out to be similar to or slightly higher than those of other methods, for both dry and saturated conditions. 2) The safe factor of sandy soil applied with GLE method turned out to be slightly higher than those of other methods. But when applied with Bishop's simple method, it appeared to be slightly higher than those of other methods. 3) The safe factor of ordinary soil applied with GLE method showed the highest result. 4) Janbu method showed the lowest safe factor among all the methods for the above three types of soils.

• Journal of the Korean housing association
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• v.7 no.2
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• pp.69-77
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• 1996

Mobility in housing is a normative way to satisfy family needs for· better· living conditions. In the context of relative decisions. mobility can be understood as forced relocation or unforced relocation In making relocation. the household chooses a particular 'environmental quality profile. Therefore. the understanding of mobility and relocation in housing is needed for· the developing and planning of housing evnironment. The major findings are s follows ;1. The motives of mobility are composed of 4 factors('material porseperity’, 'convenience· safety'. environmental improvement' and 'forced relocation'). Especially, 'material prosperity' was defined the most fundamental factor· for. 2. The components of housing environment quality were composed of 3 factors related to the scale of home environment. They were 'neighborhood character factor', 'dwelling character· factor·'. And 'location character· factor'. The factor 'neighborhood character' was defined the basic factor· to choose for the housing environmental quality profile.3. It was examined that the motives of mobility and the components of home environmental quality were significantly different by the household characteristics (income. family life cycle. and tenure type).