• Journal of the Korean Society for Nondestructive Testing
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• v.18 no.2
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• pp.112-120
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• 1998

A nondestructive evaluation technique was developed for the quantitative determination of the reinforcement volume fractions in particulate reinforced metal matrix composites. The proposed technique employed a composite micromechanics which accounts for the microstructure of the composite medium together with the measurement of anisotropic electrical conductivity. When the measured conductivity was coupled with the theoretically predicted conductivity, the unknown reinforcement volume fraction was calculated. An analytical model based on the Mori-Tanaka method was described which relates the NDE signatures to the composite microstructure. The volume fractions were calculated using eddy current measurements made on a wide range of silicon carbide particulate ($SiC_p$) reinforced aluminum (Al) matrix composites. The calculated $SiC_p$ volume fractions were in good agreement with the measured volume fractions in the range of 0-30%. The technique was also found to be effective in estimating the total volume percentage of reinforcement and intermetallic compound formed during the processing stage.

• Journal of the Korea Society of Computer and Information
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• v.25 no.9
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• pp.21-29
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• 2020

In this paper, we propose quantitative evaluation method that enable security comparison between Security Container Runtimes. security container runtime technologies have been developed to address security issues such as Container escape caused by containers sharing the host kernel. However, most literature provides only a analysis of the security of container technologies using rough metrics such as the number of available system calls, making it difficult to compare the secureness of container runtimes quantitatively. While the proposed model uses a new method of combining the degree of exposure of host system calls with various external vulnerability metrics. With the proposed technique, we measure and compare the security of runC (Docker default Runtime) and two representative Security Container Runtimes, gVisor, and Kata container.

• Journal of the Korean Chemical Society
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• v.58 no.3
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• pp.303-312
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• 2014

In this study, we analyzed the characteristics of science academic achievement by multiple culture and North Korean migrant students types, percentage of correct answer and discrimination per items per groups, and contents domains using quantitative and qualitative method in the National Assessment of Educational Achievement (NAEA). As a results of analysis, the degree of science academic achievement of the students from multiple culture and North Korean is much lower than that of the general students. Also, the science academic achievement of the students from multiple culture and North Korean migrant is different from the general students. Especially, science academic achievement of the immigrated students and the North Korean migrant students was lowest. The analysis of items that the difference of the percentage of correct answer was large showed that the students from multiple culture and North Korean migrant were equally weak to it in all contents domains, but that the students from international marriage family born in country were weak in some areas. Therefore, the appropriate the teaching and learning method and the educational support is needed considering the group situation, so the educational implications are discussed.

• Atmosphere
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• v.25 no.1
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• pp.67-83
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• 2015

Predicting the location and intensity of precipitation still remains a main issue in numerical weather prediction (NWP). Resolution is a very important component of precipitation forecasts in NWP. Compared with a lower resolution model, a higher resolution model can predict small scale (i.e., storm scale) precipitation and depict convection structures more precisely. In addition, an ensemble technique can be used to improve the precipitation forecast because it can estimate uncertainties associated with forecasts. Therefore, NWP using both a higher resolution model and ensemble technique is expected to represent inherent uncertainties of convective scale motion better and lead to improved forecasts. In this study, the limited area ensemble prediction system for the convective-scale (i.e., high resolution) operational Unified Model (UM) in Korea Meteorological Administration (KMA) was developed and evaluated for the ensemble forecasts during August 2012. The model domain covers the limited area over the Korean Peninsula. The high resolution limited area ensemble prediction system developed showed good skill in predicting precipitation, wind, and temperature at the surface as well as meteorological variables at 500 and 850 hPa. To investigate which combination of horizontal resolution and ensemble member is most skillful, the system was run with three different horizontal resolutions (1.5, 2, and 3 km) and ensemble members (8, 12, and 16), and the forecasts from the experiments were evaluated. To assess the quantitative precipitation forecast (QPF) skill of the system, the precipitation forecasts for two heavy rainfall cases during the study period were analyzed using the Fractions Skill Score (FSS) and Probability Matching (PM) method. The PM method was effective in representing the intensity of precipitation and the FSS was effective in verifying the precipitation forecast for the high resolution limited area ensemble prediction system in KMA.

• KIEAE Journal
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• v.15 no.6
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• pp.27-36
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• 2015

Purpose: The definition and factors of passive design being the sustainable method of building plan through the preceding research is deducted and the effect of passive design within the public library by applying the deducted factors in the case of built public libraries and further the realization plan of green library aimed to be reviewed in this research. Method: This study is to induce common elements of architecture plan for public library and passive design, and assess application level of re-classified elements of sustainable public library in order to analyze present condition of passive design applied on facilities of public library. First, related laws and planning standards of public library will be reviewed, then the definition of passive design will be considered using advanced research. Through advanced research related to planing elements and passive design for library induced from various plans for library standards, a common ground of induced passive design element will be transformed into assessment items and practices to be analyzed. Result: Libraries which are and are not preliminarily certified by G-SEED will be compared with each other in order to analyze the effects of passive design on G-SEED. Even though various passive elements such as load reduction of air conditioning and energy efficiency exist, there are no assessment tool within G-SEED. The fact that there are only standards for temporary methods such as utilization of construction material and installation of equipment highlights the challenges in quantitative evaluation.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.44 no.2 s.314
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• pp.55-62
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• 2007

This paper proposes method to get exquisite third dimension data removing included noise by error that occur in third dimension reconstruction through camera auto-calibration. Though reconstructing third dimension data by previous noise removing method, mesh that area is wide is happened problem by noise. Because mesh's area is important, the proposed algorithm need preprocessing that remove unnecessary triangle meshes of acquired third dimension data. The research analyzes the characteristics of noise using the area information of 3-dimensional meshes, separates a peek noise and a Gauss noise by its characteristics and removes the noise effectively. We give a quantitative evaluation of the proposed preprocessing filter and compare with the mesh smoothing procedures. We demonstrate that our effective preprocessing filter outperform the mesh smoothing procedures in terms of accuracy and resistance to over-smoothing.

• Journal of the Korean Society of Clothing and Textiles
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• v.36 no.2
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• pp.152-164
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• 2012

This study develops a valid and reliable scale to evaluate customer orientation for clothing salespeople in order to provide a foundation for systematic and empirical research in the apparel industry. The study was conducted in two phases. First, a scale was developed to evaluate the customer orientation of clothing salespeople through a qualitative method. The second phase involved the verification of the validity of the developed evaluation questions through a quantitative method. The subjects of this study were 327 clothing salespeople, and the results were analyzed using AMOS 7.0 and SPSS 15.0. The results were as follows: First, customer orientation questions were elicited from in-depth interviews with fashion sales-people, analyses of fashion magazine articles, and previous studies. From the results, 38 preliminary questions were selected based on categorization, modification, and expert analyses of the content validity. Second, in order to verify the validity of the customer orientation scale that consisted of 24 questions in 7 factors, we performed a verification of the convergent validity through an assessment of the magnitude of standardization factor loading, average variance extracted (AVE), and construct reliability. Discriminant validity was verified using the AVE of each of the two constructs and a comparison of the square of the correlation between the constructs. According to the results, the measured values were above or near the guideline values that demonstrates the validity of the customer orientation scale.

• Journal of Gifted/Talented Education
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• v.22 no.1
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• pp.197-215
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• 2012

The purpose of this study was to analyze the research trends of 114 papers about mathematical creativity published in domestic journals from 1997 to 2011 with regard to the years, objects, subjects, and methods of such research. The research of mathematical creativity education has been studied since 2000. The frequent objects in the research were non-human, middle and high school students, elementary students, gifted students, teachers (in-service and pre-service), and kindergarteners in order. The research on the teaching methods of mathematical creativity, the general study of mathematical creativity, or the measurement and the evaluation of mathematical creativity was active, whereas that of dealing with curricula and textbooks was rare. The qualitative research method was more frequently used than the quantitative research one. The mixed research method was hardly used. On the basis of these results, this paper shows how mathematical creativity was studied until now and gives some implications for the future research direction in mathematical creativity.

• Journal of the Korean Society for Nondestructive Testing
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• v.31 no.5
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• pp.543-551
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• 2011

Steam generator tubes for nuclear power plants contain the local shape transitions on their inner or outer surface such as dent, bulge, over-expansion, eccentricity, deflection, and so on by the application of physical force during the tube manufacturing and steam generator assembling and by the sludge (that is, corrosion products) produced during the plant operation. The structural integrity of tubes will be degraded by generating the corrosive crack at that location. The profilometry using the traditional bobbin probes which are currently applied for measuring the profile change of tubes gives us basic information such as axial locations and average magnitudes of deformations. However, the three-dimensional quantitative evaluation on circumferential locations, distributional angle, and size of deformations will have to be conducted to understand the effects of residual stresses increased by local deformations on corrosive cracking of tubes. Steam generator tubes of Korean standard nuclear power plants expanded within their tube-sheets by the explosive expansion method and suffered from corrosive cracks in the early stage of power operation. Thus, local deformations of steam generator tubes at the top of tube-sheet were measured with an advanced rotating probe and a laser profiling system for the two cases where the tubes expanded by the explosive expansion method and hydraulic expansion. Also, the trends of eccentricity, deflection, and over-expansion of tubes were evaluated. The advanced eddy current profilometry was confirmed to provide accurate information of local deformations compared with laser profilometry.

• Journal of Soil and Groundwater Environment
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• v.21 no.4
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• pp.42-49
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• 2016

Step-drawdown pumping tests for identifying the improvement of groundwater well performance after rehabilitation treatments were conducted in three longstanding wells. Three selective mechanical treatment methods including power bubble, high-voltage electric pulse, and air surging were applied to these wells and the applicability of these methods to secure additional groundwater resources were evaluated quantitatively. Commonly, drawdown at final stage of stepdrawdown pumping tests after rehabilitation decreased by as much as 0.61~0.70 meters compared to those before rehabilitation. In addition, final specific drawdown values of three wells increased from 9% to 14% after rehabilitation. Formation loss coefficient and well loss coefficient decreased to 6.1% and 60.6%, respectively, indicating some clogging materials by precipitation/corrosion/microbe within pores of aquifer materials, gravel packs, and screens were effectively removed by applied methods. Decrease of formation loss coefficient was higher in the well applied by the power bubble method meanwhile high-voltage electric pulse method demonstrated the higher decrease of well loss coefficient. Additionally secured groundwater amounts after rehabilitation ranged from 23.3 to 32.1 m³/day, which account for 8~16% of initially developed pumping rates of the wells. From the results of this study, the effective selection of rehabilitation treatments considering aquifer characteristics are expected to contribute to secure groundwater resources for irrigation as well as to plan systematic management program for groundwater resources in rural area.