• Asian-Australasian Journal of Animal Sciences
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• v.16 no.4
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• pp.489-493
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• 2003

Reproductive traits of sows are determined chiefly by the genetic background of the dam herself. Whether the breed of the serviced boars also contributes is not yet clear. A total of 8,946 litters of Landrace (L) sows from 68 farms were examined. Of these, 876, 1,260, and 6,810 litters were produced from natural mating with L, Yorkshire (Y), and Duroc (D) breeds, respectively. The birth litter size (BLS), weaning litter size (WLS), live born piglets (LBP), and survival rate % (SR), of every litter were recorded. A general linear-model procedure was followed to estimate the effects of boars' breed (B), parity (P) and B${\times}$P interaction on the reproductive traits of the sows. Results show that BLS, WLS, and LBP were all significantly (p<0.001) affected by B and P. SR% was significantly influenced by B but not by P. L sows crossbred with Y or purebred with L produced litters with higher BLS, WLS, and LBP values than those bred with D. Pure L breeding yielded litters with lower SR% than did crossbreeding with D, while the difference between SR% due to LY and that due to LD crossbreeding was not significant. The interaction of B with P was significant with respect to BLS, WLS, and LBP (p<0.001), but not SR%. No significant B effect on reproductive traits was measured in sows at their first parity; but at latter parities, LL or LY produced litters with similarly high BLS, WLS and LBP, which values were all significantly greater than those of LD litters. The breed of boar evidently affected the subsequent reproductive performance of L sows and this effect may be further manipulated by the parity effect. Breed differences in semen quality and the success of fetus development with different interactions of the genetic background with the uterus function of the sow that may contribute to these effects are discussed.

• The Korean Journal of Applied Statistics
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• v.8 no.2
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• pp.87-97
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• 1995

When there is no main effcts or only one main effect in a $2 \times 2$ factorial design, Type I error rates and power for the rank transformed F test (FR test) for interaction are nearly equal to those of the classical F test. However the power of FR test is quite superior under the exponential distribution rather than the of FR test is quite superior under the exponential distribution rather than the normal distribution. Meanwhile when both main effects are in the model, Type I error rates of FR test, compared with those of F test, decrease as the effect size increases and are dependent on the fashion in which main effects are constructed. In addition, the power of FR test increases as the effect size and the sample size increase and is highly dependent on the manner in which main effects are constructed and the type of population distribution.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.10
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• pp.1471-1478
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• 2010

Microforming processes have recently attracted considerable attention from industry and academia since they enable the production of microscale parts using various materials at a high production rate, minimize material loss, and provide parts with excellent mechanical properties. However, for successful development and applications of the microforming process it is critical to take the tribological size effect into consideration because previous studies have shown that traditional friction models for macroscale forming generate significantly erroneous results in the case of microforming. In this paper, we performed scaled ring compression experiments to investigate the tribological size effect of aluminum and brass materials in microforming. The sensitivity of the interfacial friction to the deformation characteristics of the ring was quantitatively analyzed by the finite element analysis. In addition, a friction model based on slip line field and upper boundary techniques was used to theoretically explain the friction mechanism in microforming.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.1A
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• pp.35-41
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• 2011

In concrete structural design provisons, two methods are normally provided to control deflection; direct method and indirect method. It is more efficient to use the indirect deflection control by which the span/depth ratio is limited not to exceed an allowable deflection limit. Because actual deflections are affected by many causes, it is complicated to evaluate actual deflections. In this study, limit span/depth ratios are derived from the deflection calculated directly at the serviceability limit state in RC members. The deflection is obtained from using average curvature, which depends on materials model used. The main variables examined are tension stiffening effect, concrete strength, cross section size and compressive steel ratio. It could be appeared that more analytical consistency is secured to use the 2nd order form of tension stiffening effect. And the limit span/depth ratio is dependent on material strength, tensile and compressive steel ratio but it is independent on cross-section size.

• Earthquakes and Structures
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• v.11 no.5
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• pp.823-840
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• 2016

The plastic hinge lengths of beams and columns are a critical demand parameter in the nonlinear analysis of structures using the finite element method. The numerical model of a plastic hinge plays an important role in evaluating the response and damage of a structure to earthquakes or other loads causing the formation of plastic hinges. Previous research demonstrates that the plastic hinge length of reinforced concrete (RC) columns is closely related to section size, reinforcement ratio, reinforcement strength, concrete strength, axial compression ratio, and so on. However, because of the limitations of testing facilities, there is a lack of experimental data on columns with large section sizes and high axial compression ratios. In this work, we conducted a series of quasi-static tests for columns with large section sizes (up to 700 mm) and high axial compression ratios (up to 0.6) to explore the propagation of plastic hinge length during the whole loading process. The experimental results show that besides these parameters mentioned in previous work, the plastic hinge of RC columns is also affected by loading amplitude and size effect. Therefore, an approach toward considering the effect of these two parameters is discussed in this work.

• The Journal of Korean Academic Society of Nursing Education
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• v.23 no.1
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• pp.15-26
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• 2017

Purpose: This study evaluated the efficacy of a communication ability enhancement program for nursing students in Korea through a systematic review of literature and meta-analysis. Methods: The researchers searched data-bases, including the Data Base Periodical Information Academic, Research Information Sharing Service, National Digital Science Library and National Assembly Library. The key words used included 'communication' and 'nursing student'. The researchers evaluated articles published up to July 2016. Out of 381 selected articles, 20 clinical trial studies were meta-analyzed. Each article was evaluated in accordance with the Checklist of Scottish Intercollegiate Guideline Network. The effect size of communication ability, self-efficacy and interpersonal relations were synthesized by a random effects model from analysis software (R 3.2.3). The heterogeneity of effect size was analyzed by exploratory and confirmatory moderator analysis. Results: The overall effect size of the program was of a moderate level (SMD=0.78, 95% CI: 0.49~1.07) along with each outcome of self-efficacy (SMD=0.80, 95% CI: 0.23~1.37), and interpersonal relations (SMD=0.47, 95% CI: 0.14~0.80). For heterogeneity, moderator analysis was performed, by grade, and a statistically significant moderator was found. Conclusion: It is evident that a communication ability enhancement program for nursing students is moderately effective in improving communication ability, self-efficacy and interpersonal relations.

• Journal of the Korean Institute of Educational Facilities
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• v.13 no.4
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• pp.5-14
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• 2006

The purpose of this study is to suggest a model plan for a mini school using the lower part of the apartment. In order to reach this model, firstly, the existing condition of over populated schools is analyzed, secondly, the Proper size and planning module for a mini school are suggested through the analysis of 7th national curriculum for the education, and thirdly, the model plan for a mini school is suggested using the apartment under construction. Mini school will be expected to solve the problems from over populated schools, and enhance the educational effect for the primary students.

• Journal of computational fluids engineering
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• v.13 no.2
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• pp.62-67
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• 2008

This study aims to investigate numerically the static stiffness characteristics of porous air bearing and to estimate appropriate permeability values of porous medium. In particular, a new roughness model is proposed and implemented into the commercial CFD code (FLUENT Ver. 6.2) by using C language based user subroutine. The predicted results are extensively compared with experimental data. The roughness model is also validated through comparison with the results from open literature. It is found that the predictions for static stiffness are in good agreement with experimental data. Therefore, the suggested model based on the roughness Reynolds number can be used in studying the stiffness characteristics of porous air bearing effectively. In addition, numerical simulations of various diameter size and conditions are conducted. According the results, it is expected that the static stiffness of porous air bearing has the non-linear characteristics.

• Journal of the Korean Applied Science and Technology
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• v.21 no.3
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• pp.259-266
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• 2004

Film properties of monodispersed model composite latexes with particle size of 190 nm, which consist of n-butyl acrylate as a soft phase monomer and methyl methacrylate as a hard phase monomer with different morphology was examined. Five different types of model latexes were used in this study such as random copolymer particle, soft-core/hard-shell particle, hard-core/soft-shell particle, gradient type particle, and mixed type particle. Tensile strength and tensile elongation at break of final films were evaluated. Those properties can be interpreted in terms of PBA/PMMA phase ratio and their morphology. The interfacial adhesion strength was also evaluated using $180^{\circ}$ peel strength measurement and cross hatch cutting test.

• Journal of the Korean Society of Safety
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• v.23 no.4
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• pp.30-35
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• 2008

The present study has been conducted to examine the effect of grid resolution on the predicted results for electric cable fire using pyrolysis model in FDS(Fire Dynamics Simulator, version 5). The grid independent test for different grid resolutions has been performed for a PE coating cable and the grid resolution is defined by the non-dimensional characteristic length of fire and mean grid size. The calculated maximum heat release rate and mean flame spread rate were almost constant for higher grid resolution of 20${\sim}$25 and the computing time for the grid resolution takes approximately 20hours to solve flame propagation with pyrolysis model. The geometrical simplification of a electric cable dose not greatly affect on the maximum heat release rate and flame spread rate and the rectangular approximation of cable shape gives acceptable result comparing with the round cable with stepwise grid.