• The Korean Journal of Rheology
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• v.10 no.4
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• pp.202-216
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• 1998

Improved version of previous 'Orthotropic' closure approximation, termed 'ORW' has been numerically developed using new homogeneous flow data. Previous 'Orthotropic' closure approximation, i.e., ORF or ORL showed non-physical oscillation for interaction coefficient $C_1$<0.001 at simple shear flow. It also shows non-physcial oscillation and under-prediction compared with 'Distribution Function Calculation' at non-homogeneous flow of center-gated disk. These phenomena are mainly due to the flow data of 'Distribution Function Calculation' which were used for least-square optimization. ORW obtained by fitting flow data of low interaction coefficient does not show non-physical oscillation and results in reasonably good behaviors at non-homogeneous flows as well as homogeneous flows. Fitting function forms have not been found to improve overall behaviors. It has been found that considering all the eigenvalues of orientation tensor (including the third eigenvalues) might end up with a better closure approximation than just considering the first and second eigenvalues. It is, however, very important and yet difficult to select appropriate function forms of eigenvalues. Numerical simulation including coupling and in-plane velocity gradient effects were performed for injection mold filing process with a film-gated strip and a center-gated disk using ORW and various other closure approximations for comparisons. Although ORW is in excellent agreement with 'Distribution Function Calculation', the predicted results seem to have consistent error in comparison with experimental data. The diffusivity term with constant interaction coefficient might have to be further investigated in order to accurately describe orientation states.

• Journal of Korean Society of Rural Planning
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• v.16 no.2
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• pp.57-64
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• 2010

This study aims to understand the degree of inequality of surveyed amenity resources and identify which resource and region have the highest concentration by estimating Lorenz Curve and the Gini's Coefficient. The Lorenz Curve and Gini's Coefficient derived from economics are introduced as tools for investigating and quantifying regional variability of amenity resources concentration. This study describes the concepts underlying the application of the Gini's coefficient to measure the concentration of amenity resources in 11 regions, Chungbuk Province, Korea. The Lorenz Curve presents a graphical view of the cumulative distribution of amenity resources and the Gini's Coefficient provides a single-parameter measure of the distributional concentration of amenity resources. Also the Gini's Coefficient is compared to the number of amenity resource for understanding distributional difference between concentration and quantitative distribution of amenity resources. The results demonstrate significantly different regional variation according to the amenity variables: almost intact nature, interaction between nature and man, man-made.

• Communications for Statistical Applications and Methods
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• v.26 no.1
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• pp.69-78
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• 2019

A structured model with both single-index and varying coefficients is a powerful tool in modeling high dimensional data. It has been widely used because the single-index can overcome the curse of dimensionality and varying coefficients can allow nonlinear interaction effects in the model. For high dimensional index vectors, variable selection becomes an important question in the model building process. In this paper, we propose an efficient estimation and a variable selection method based on a smoothing spline approach in a partially linear single-index-coefficient regression model. We also propose an efficient algorithm for simultaneously estimating the coefficient functions in a data-adaptive lower-dimensional approximation space and selecting significant variables in the index with the adaptive LASSO penalty. The empirical performance of the proposed method is illustrated with simulated and real data examples.

• Bulletin of the Korean Chemical Society
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• v.35 no.9
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• pp.2679-2683
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• 2014

Mechanisms underlying the impacts of interactions between carbon nanoparticles (CNPs) and ionic liquids (ILs) on the physicochemical behavior of CNPs need to be more full worked out. This manuscript describes a theoretical investigation at multiple levels on the interactions of fullerene $C_{60}$ with 21 imidazolium-based ILs of varying alkyl side chain lengths and anionic types and their impacts on $C_{60}$ dispersion behavior. Results show that ${\pi}$-cation interaction contributed to mechanism of the $C_{60}$-IL interaction more than ${\pi}$-anion interaction. The calculated interaction energy ($E_{INT}$) indicates that $C_{60}$ can form stable complex with each IL molecule. Moreover, the direction of charge transfer occurred from IL to $C_{60}$ during the $C_{60}$-IL interaction. Quantitative models were developed to evaluate the self-diffusion coefficient of $C_{60}$ ($D_{fullerene}$) in bulk ILs. Three interpretative molecular descriptors (heat of formation, $E_{INT}$, and charge) that describe the $C_{60}$-IL interactions and the alkyl side chain length were found to be determinants affecting $D_{fullerene}$.

• The Journal of the Korea Contents Association
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• v.10 no.11
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• pp.285-293
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• 2010

The purpose of this study was to analyze the predictors of students depress, Interaction anxiety, school adjustment on cellular phone addiction of teenagers. The subjects for this study were 613 teenagers composed of 249 middle school students, 337 high school students in Daejeon. The data was conducted by using a correlations coefficient and the multiple regression analysis. According to the analysis result, correlations among measured variables of students depress, interaction anxiety, school adjustment, cellular phone addiction were significant. Secondly, the multiple regression analysis result showed that students depress, peer relations, and interaction anxiety variables to most greatly explain cellular phone addiction. These results indicate that cellular phone addiction related to depress, interaction anxiety of teenagers.

• Steel and Composite Structures
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• v.38 no.1
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• pp.67-78
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• 2021

The use of composite beams with partial interaction, with less shear connectors than those required for full interaction, may be advantageous in many situations. However, these beams tend to show higher deflections compared to beams with full interaction, and codified expressions for the calculation of such deflections are not fully developed and validated. Thus, this paper presents a comprehensive numerical study on the deflections of steel-concrete composite beams with partial interaction. Efficient numerical models of full-scale composite beams considering material nonlinearities and contact between their parts have been developed by means of the advanced software ABAQUS, including a damage model to simulate the concrete slab. The FE models were validated against experimental results, and subsequently parametric studies were developed to investigate the influence of the shear connection degree and the coefficient of friction in the deflection of composite beams. The comparison of predicted deflections using reference codes (AISC, Eurocode-4 and AS-2327.1) against numerical results showed that there are still inaccuracies in the estimation of deflections for the verification of the serviceability limit state, according to some of the analyzed codes.

• Journal of Korean Academy of Nursing
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• v.46 no.3
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• pp.431-442
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• 2016

Purpose: This paper was conducted to validate the Korean version of the Peer Group Caring Interaction Scale (PGCIS-K) that measures caring behaviors as experienced by nursing students. Methods: Translation of the PGCIS-K was validated through forward-backward translation methods. Survey data were collected from 218 nursing students in a nursing school. Construct validity and criterion-related validity were evaluated. Internal consistency and the Guttman split-half coefficient were calculated to assess reliability. Results: The PGIS-K showed reliability except for 4 items (Cronbach's ${\alpha}=.91$, Guttman split-half coefficient=.85), which were low (<.30) or negatively correlated with the total scale. A 12-item reduced form of the PGCIS-K was developed by item-analysis and construct validity evidence. Factor loading for the 12 items on 2 factors ranged from .47~.82, which explained 58.4% of the total variance. Two factors were named 'modeling and assistance (Cronbach's ${\alpha}=.87$)' and 'communication and sharing (Cronbach's ${\alpha}=.82$)'. Convergent validity, discriminant validity, and criterion validity were supported according to the correlation coefficients of the 2 factors with other measure. Conclusion: The findings suggest preliminary evidence that the 12-item PGCIS-K can be used to measure nursing students' peer group caring interactions in Korea. Additional studies are recommended to continue the psychometric evaluation of this scale. Also, it can be extended to measure graduate nursing students or staff nurses' peer group caring interaction.

• Journal of Convergence for Information Technology
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• v.9 no.8
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• pp.83-92
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• 2019

This descriptive convergence research aimed to explore predictors of retention intention of nurses. Participants were 207 nurses from five small and medium-sized hospital located in city G and province J. Data were analyzed with descriptive statistics, independent t-test, one-way ANOVA, pearson's corelation coefficient and stepwise multiple regression. Among predictors, nursing practice environment, age, peer group caring interaction, current hospital work experience, and assignment to desired department significantly affected retention intention and nursing practice environment had the greatest effect on retention intention(${\beta}=.35$). Based on the results of this study, it is necessary to make efforts to improve nursing practice environment, caring interaction and good relationship between organizations.

• Nuclear Engineering and Technology
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• v.27 no.6
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• pp.811-824
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• 1995

The CANDU element bowing is attributed to actions of both the thermally induced bending moments and the bending moment due to hydraulic drag and mechanical loads, where the bowing is defined as the lateral deflection of an element from the axial centerline. This paper consider only the thermally-induced bending moments which are generated both within the sheath and the fuel and sheath by an asymmetric temperature distribution with respect to the axis of an element The generalized and explicit analytical formula for the thermally-induced bending is presented in con-sideration of 1) bending of an empty tube treated by neglecting the fuel/sheath mechanical interaction and 2) fuel/sheath interaction due to the pellet and sheath temperature variations, where in each case the temperature asymmetries in sheath are modelled to be caused by the combined effects of (i) non-uniform coolant temperature due to imperfect coolant mixing, (ii) variable sheath/coolant heat transfer coefficient, (iii) asymmetric heat generation due to neutron flux gradients across an element and so as to inclusively cover the uniform temperature distributions within the fuel and sheath with respect to the axial centerline. As the results of the sensitivity calculations of the element bowing with the variations of the parameters in the formula, it is found that the element bowing is greatly affected relatively with the variations or changes of element length, sheath inside diameter, average coolant temperature and its variation factor, pellet/sheath mechanical interaction factor, neutron flux depression factor, pellet thermal expansion coefficient, pellet/sheath heat transfer coefficient in comparison with those of other parameters such as sheath thickness, film heat transfer coefficient, sheath thermal expansion coefficient and sheath and pellet thermal conductivities.

• Korean Journal of Materials Research
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• v.29 no.7
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• pp.451-455
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• 2019

The electromagnetic and thermal properties of a heavy fermion $CeNi_2Ge_2$ are investigated using first-principle methods with local density approximation (LDA) and fully relativistic approaches. The Ce f-bands are located near the Fermi energy $E_F$ and hybridized with the Ni-3d states. This hybridization plays important roles in the characteristics of this material. The fully relativistic approach shows that the 4f states split into $4f_{7/2}$ and $4f_{5/2}$ states due to spin-orbit coupling effects. It can be found that within the LDA calculation, the density of states near the Fermi level are mainly of Ce-derived 4f states. The Ni-derived 3d states have high peaks around -1.7eV and spreaded over wide range around the Fermi level. The calculated magnetic of $CeNi_2Ge_2$ with LDA method does not match with that of experimental result because of strong correlation interaction between electrons in f orbitals. The calculations show that the specific heat coefficient underestimates the experimental value by a factor of 19.1. The discrepancy between the band calculation and experiment for specific heat coefficient is attributed to the formation of a quasiparticle. Because of the volume contraction, the exchange interaction between the f states and the conduction electrons is large in $CeNi_2Ge_2$, which increases the quasiparticle mass. This will result in the enhancement of the specific hear coefficient.