• Korean Journal of Child Studies
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• v.16 no.1
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• pp.99-112
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• 1995

This study aimed (1) to classify Korean kindergarten childrens' attachment to their mothers based on a system for classifying attachment organization developed by Main and Cassidy (1988), and (2) to investigate the relationship of attachment and temperament and mothers' child rearing behavior. 76 kindergarteners and their mothers were observed and videotaped in the strange situation. The modified PTQ(Parent and Teacher Temperament Questionnaire) for children 3-7 years of age and the IPBI(Iowa Parent Behavior Inventory: Mother Form) were administered respectively to 76 mothers to assess their parenting behavior and their children's temperament. The data were analyzed by percentiles, Pearson's correlations, and canonical correlation analysis. Results indicated that there was a little difference between the attachment classification of Main and Cassidy(1988) and that of Korean kindergarten children. There were significant correlations between children's temperament and the attachment to their mother. And mothers' parenting behavior was significantly related to the security of attachment. The canonical correlation analysis indicated that independent variables all together accounted for about 7.5% of the variation in attachment-variables.

• Journal of Mechanical Science and Technology
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• v.20 no.12
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• pp.2189-2196
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• 2006

The present work is concerned with the development of a procedure for adaptive computations of shear localization problems. The maximum jump of equivalent strain rates across element boundaries is proposed as a simple error indicator based on interpolation errors, and successfully implemented in the adaptive mesh refinement scheme. The time step is controlled by using a parameter related to the Lipschitz constant, and state variables in target elements for refinements are transferred by $L_2$-projection. Consistent tangent moduli with a proper updating scheme for state variables are used to improve the numerical stability in the formation of shear bands. It is observed that the present adaptive mesh refinement procedure shows an excellent performance in the simulation of shear localization problems.

• Journal of the Korean Society for Heat Treatment
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• v.33 no.4
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• pp.185-192
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• 2020

In this study, materials characterization of pure copper and copper based carbon nano-tube composite prepared by powder metallurgy method were investigated. Prior to evaluate materials characterization, spark plasma sintering processing variables such as sintering temperature, pressure, thickness and diameter of compacts was optimized to ensure the microstructure and materials property of pure Cu and Cu-CNT composite. In addition, corrosion behavior of Cu-based CNT composite produced by powder sintering method was investigated. It was confirmed from this study that the corroded surfaces of the composite shows less dissolution compared with pure copper in 3.5 wt% NaCl solution. The measured corrosion current density (I_corr) indicates improved corrosion property of Cu based composite containing small additions of CNTs in chloride containing media. Micro-galvanic activity between Cu and CNT was not observed in given sintering condition.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.8
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• pp.1719-1726
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• 2002

Design variables and design parameters are rarely deterministic in practice. Robust optimal design takes into consideration of the uncertainties in the design variables and parameters. Robust optimization methodology with probability constraints requires a lot of system analyses fer calculating failure probability of each constraint. By introducing an envelope function to reduce the number of constraints, efficiency of robust optimization techniques can be considerably improved. Through four illustrative examples, it is shown that the number of system analyses is greatly decreased while little differences in the optimum results are observed.

• The Korean Journal of Applied Statistics
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• v.24 no.2
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• pp.425-433
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• 2011

Reject inference in credit scoring is a statistical approach to adjust for nonrandom sample bias due to rejected applicants. Function estimation approaches are based on the assumption that rejected applicants are not necessary to be included in the estimation, when the missing data mechanism is missing at random. On the other hand, the density estimation approach by using mixture models indicates that reject inference should include rejected applicants in the model. When mixture models are chosen for reject inference, it is often assumed that data follow a normal distribution. If data include missing values, an application of the normal mixture model to fully observed cases may cause another sample bias due to missing values. We extend reject inference by a multivariate normal mixture model to handle incomplete characteristic variables. A simulation study shows that inclusion of incomplete characteristic variables outperforms the function estimation approaches.

• Journal of Korean Biological Nursing Science
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• v.13 no.2
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• pp.185-192
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• 2011

Purpose: The purpose of this study was to investigate the cognition, balance, quality of life and the correlation of these variables in the elderly. Methods: This study was a descriptive survey research. The samples were 86 and variables were measured by structured questionnaire and physical balance movements. The data were analyzed with %, t-test, ${\chi}^2$-test, ANOVA, Pearson correlation by SPSS ver. 19.0 for windows. Results: The cognition score was 24.02 which means within normal limits. The balance score was 11.83 and the score of QOL was 82.67 which were similar to other research results. There were significant differences in the balance (p<.001) and the QOL (p=.004) by the cognition level. A significant correlation among the cognition, balance and the QOL was observed. Conclusion: The cognition was closely related with the balance and the QOL. The cognitive stimulus and the balance exercise could help the improvement of QOL in the elderly.

• Bulletin of the Korean Space Science Society
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• 2004.04a
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• pp.94-94
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• 2004

We report an investigation of BOES imaging performance variation against observational variables. Average FWHM of the ThAr reference spectra recorded in 10 spectral image frames observed during the night of January 5th, 2004 was computed. The averaged FWHM data was then correlated with observational variables including telescope altitude, air mass, focus position, exposure time, detector temperature, gain settings and S/N ratio. (omitted)

• Journal of Astronomy and Space Sciences
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• v.16 no.2
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• pp.115-130
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• 1999

We report the discovery of 17 new RR Lyrae variables in the central region ($\rleq1'$) of the globular cluster M53. There candidates were identified by using the Welch & Stetson (1993) technique and confirmed by checking individual light curves in both B and V bands. The color-magnitude diagram of the horizontal-branch stars in the central region is compared with that for stars observed in the outer region by Rey et al. (1998). Including the new data from this study, we estimate the fraction of c typeRR Lyrae variables, n(c)/n(ab + c), to be 0.43 which agrees well with the valuse of other Oosterhoff group II clusters.

• Transactions of Materials Processing
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• v.7 no.4
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• pp.393-399
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• 1998

For minimizing wall thickness thinning of circular shells, a new stamping technology, the deep draw-ing process combined with ironing is approached and investigated. The design requirements for the deep drawing shells are to keep the optimum wall thickness with max. 10 percent thickness thinning of the initial blank thickness, to make uniform thickness strain distribution for the wall of circular shell and to improve the shape accuracy for the roundness and concentricity. In order to check the validity and effectiveness of proposed work, a sample process design is applied to a circular shell needed for a 4multi-stepped deep drawing. Through experiments, the variations of the thickness strain distribution in each drawing process are observed. Also a series of experiments are performed to investigate optimum process variables such as the geometry of tooling, radius and drawing rate. In particular, the advantage of current approach with ironing is shown in contrast to the conventional deep drawing process. From the results of proposed method, the optimum value of process variables are obtained, which contribute more uniform thickness strain distribution and better quality in the drawn product.

• Publications of The Korean Astronomical Society
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• v.15 no.spc1
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• pp.113-118
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• 2000

A magnetic cataclysmic variable has a rotating magnetic white dwarf which accretes matter from its late type companion. Kim & Beuermann (1995) presented a phenomenological model of the accretion from its surrounding structure e.g., a disk into the magnetosphere of the white dwarf, and presented results for the spin modulated X-ray spectrum and light curves. Using this model, we calculate the optical continuum and line emission which result from reprocessing of X-rays in the accretion stream within the magnetosphere. Penning (1985) suggested the observed spin-modulated radial-velocity variations might result from reprocession of X-rays in the disk. We, however, find the radiation can be originated from the magnetosphere accretion stream. We use the same geometrical model to calculate the optical and the X-ray behaviour. The results from the two wavelength bands are internally consistent. We conclude that this approach will increase the diagnostic accuracies of the results.