• Proceedings of the KIEE Conference
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• 1999.11c
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• pp.512-514
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• 1999

The damping ratio $\zeta$ of a continuous 2nd order response which passes all the points of the discrete response of a 2nd order discrete system(envelope curve) is a function of only the location of the closed-loop pole and ie not at all related to the location of the zero. And the peak overshoot of the envelope curve is uniquely specified by the damping ratio $\zeta$, which is a function of solely the closed-loop pole location, and the angle $\alpha$ which is determined by the relative location of the zero with respect to the closed-loop complex pole. Therefore, if the zero slides on the real axis with the closed-loop complex poles being fixed, then the angle $\alpha$ changes however the damping ratio $\zeta$ does not. Accordingly, when the closed-loop system poles are fixed, the peak overshoot is function of $\alpha$ or the system zero. In this thesis the effects of the relative location of the zero on the system performance of a second order discrete system is studied.

• Transactions on Electrical and Electronic Materials
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• v.13 no.6
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• pp.297-300
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• 2012

Lead-free (1-x)$(Na_{0.5}K_{0.5})NbO_3-xLiNbO_3$, i.e., NKN-LNx (x=0.0, 0.1, 0.2, 0.3, 0.4 mol) was prepared using the conventional solid state reaction method. The effects of LN mixing on the ferroelectric properties of NKN-LNx ceramics were studied using a dielectric constant and P-E (Polarization-electric field) measurements. Ferroelectricity was observed in the composition for x approximately varying between 0.0 and 0.4. Minimum remanent polarization $2P_r=5C/cm^2$ was achieved in the composition for x = 0.2. The ferroelectric phase transition temperature $T_C$ increased with increasing LN content. The ferroelectric phase transition of NKN-LNx ($x{\geq}0.1$) is a second-order phase transition, and that of NKN-LNx ($x{\leq}0.2$) is a first-order phase transition. These results indicate that the ferroelectric phase transition temperature of NKN-LNx change from that of second-order to weak first-order phase transition according to the LN content.

• Korean Journal of Social Welfare
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• v.43
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• pp.299-327
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• 2000

Although economic crisis is allaying in Korea, the more effective unempoyment policies are requried in this present. So in this paper, we analyze the effects of relevant factors, especially job search behaviors of the unempyoed on reemployment and look for implications to the improvement of unemployment policies. Major findings are as follows: First, we find that job search behaviors, especially the effectiveness of job search activity and job search attitude are significantly different between the unemployed and the re-employed. Second, we find that the variables of job search behaviors - the effectiveness of job search activity (number of job offers), job search attitude (reservation wage), positive use of job search methods - significantly affect the re-employment of the unemployed from logistic regression analysis results. These findings' implications are as follows: First, the approach based on search theory may be useful in finding out determinants of re-employment. Second, the effects of job search behaviors on the reemployment and their implications should be actively accepted to policy makers in order to improve the effectiveness of un-employment policies. It meams that the effects of job search behaviors must be carefully considered in making or restructuring unemployment policies and their administrations.

• Journal of the Korea Society of Computer and Information
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• v.24 no.5
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• pp.163-170
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• 2019

The purpose of this study is to examine the effects of discrimination abuser experiences and discrimination victim experiences on the human rights consciousness of children in community children, In order to understand the role of self-esteem as a mediating role between these two variables, And to find practical and policy implications. For this purpose, we selected 662 elementary school sixth graders who participated in the second panel of the community children's center, the third year (2016), as the sample and used the structural equation model validation method. As a result of this study: First, the experience of discrimination abuser against children in the community children's center has negative effects on self - esteem. Second, the self-esteem of children in the community children's center showed a statistically significant effect on human rights consciousness. Third, the experiences of child discrimination abuse and discrimination of local children's centers showed significant influence on children's consciousness of human rights through self - esteem. In conclusion, we proposed practical use measures to promote positive emotional development and human rights consciousness of children in community children's centers.

• Journal of the Korean Society of Clothing and Textiles
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• v.27 no.5
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• pp.496-504
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• 2003

The purpose of this study was (1) to identify the experimental bias which could appear person perception as results of presentation methods (2) to find out the most desirable method in presentation of stimulus. The research was a quasi experiment and the subjects were 773 male and female undergraduate students. The experimental instruments consisted of a set of stimulus and semantic differential scales of 7- point hi-polar adjectives. The collected data were analyzed by Factor Analysis, ANOVA(analysis of variance), Scheffe＇s multiple range test. The independent variables were presentation orders and presentation time of stimulus. The results were as follows: First, five factors which were potency, sociality, appearance, evaluation, activity impression dimensions emerged to account for the methods of development of stimulus. Second, the presentation order of stimulus in the combination of four stimuli sets had significant effects on the 3 impressional factors(sociality, appearance, evaluation). The presentation order of stimuli in the combination of eight stimuli set had significant effects on the 3 impressional factors(potency, sociality, appearance) and the presentation order of stimuli in the combination of eight stimuli set showed a significant effect on memorization of stimulus and the results support the recency effect. Third, the presentation time of stimuli had significant effects on the 2 impressional factors(potency, activity). 30 seconds presentation as well as free duration time resulted less experimental bias than 3 seconds presentation.

• Journal of Families and Better Life
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• v.16 no.1
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• pp.63-80
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• 1998

The purpose of this study is to analyze the effects of unstructured and spontaeous role-playing in pro-social behavior of a child. The experimental group in this study is 7 children who go to after-school class in J. social welfare facility and the controlled group is 7 children in composition class., While the experimental group did role-playing with each other the control group did not have any treatment, In order to find out effects of an experiment pre-test first post-test and second post-test were done. The results can be concluded as following. First in pre-test the degree of behavior resulted the same in experimental group and in controlled group. However in the first post-test the pro-social behavior of the experimental group with role-playing showed an improve than that of the controlled group. Therefore it can be emphasized once more that the role-playing improves pro-social behavior of a child. Second in the second post-test done 2 moth after the role-playing it was found that the pro-social behavior of experimental group keep the improved points as in the first post-test Therefore it can be concluded that the effect of role-playing on pro-social behavior of a child is continuous.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.20 no.1
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• pp.17-35
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• 2016

In this study, the dynamic behaviour of a rotating Timoshenko beam when under the actions of a variable magnitude load moving at non-uniform speed is carried out. The effect of cross-sectional dimension and damping on the flexural motions of the elastic beam was neglected. The coupled second order partial differential equations incorporating the effects of rotary and gyroscopic moment describing the motions of the beam was scrutinized in order to obtain the expression for the dynamic deflection and rotation of the vibrating system using an elegant technique called Galerkin's Method. Analyses of the solutions obtained were carried out and various results were displayed in plotted curve. It was found that the response amplitude of the simply supported beam increases with an increase in the value of the foundation reaction modulus. Effects of other vital structural parameters were also established.

• Journal of Mechanical Science and Technology
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• v.15 no.6
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• pp.788-795
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• 2001

The effects of nonequilibrium condensation on the shock boundary layer interaction over a transonic bump model were investigated experimentally and numerically. An experiment was conducted using a supersonic indraft wind tunnel. A droplet growth equation was incorporated into two-dimensional Navier-Stokes equation systems. Computations were carried out using a third-order MUSCL type TVD finite-difference scheme with a second-order fractional time step. Computation compared with the experimental results. Nonequilibirum condensation suppressed the boundary layer separation and the pressure fluctuations due to the shock boundary layer interaction. Especially the nonequilbrium condensation was helpful to suppress the high frequency components of the pressure fluctuations.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.671-677
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• 1996

This paper proposes a study on the effects of motion errors for acceleration/ deceleration types. The proposed motion errors are consisted of two errors : one due to transient response of servomechanism and the other due to gain mismatching of positioning servo motor. They are derived from using laplace transformation for the block diagram of general purpose feed drive system. In order to minimize them, the paper proposes second order polynomial regression model by using orthogonal array method which describes one of experimental methodolgies. The validity and reliability of the study was veri lied on a vertical machining center equipped with FANUC 0MC through a series of experiments and analyses.

• Structural Engineering and Mechanics
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• v.33 no.4
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• pp.447-484
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• 2009

The spatially coupled buckling, in-plane, and lateral bucking analyses of thin-walled Timoshenko curved beam with non-symmetric, double-, and mono-symmetric cross-sections resting on elastic foundation are performed based on series solutions. The stiffness matrices are derived rigorously using the homogeneous form of the simultaneous ordinary differential equations. The present beam formulation includes the mechanical characteristics such as the non-symmetric cross-section, the thickness-curvature effect, the shear effects due to bending and restrained warping, the second-order terms of semitangential rotation, the Wagner effect, and the foundation effects. The equilibrium equations and force-deformation relationships are derived from the energy principle and expressions for displacement parameters are derived based on power series expansions of displacement components. Finally the element stiffness matrix is determined using force-deformation relationships. In order to verify the accuracy and validity of this study, the numerical solutions by the proposed method are presented and compared with the finite element solutions using the classical isoparametric curved beam elements and other researchers' analytical solutions.