• Bulletin of the Korean Mathematical Society
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• v.40 no.4
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• pp.553-564
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• 2003

We give sufficient coefficient conditions for starlikeness of a class of complex-valued multivalent meromorphic harmonic and orientation preserving functions in outside of the unit disc. These coefficient conditions are also shown to be necessary if the coefficients of the analytic part of the harmonic functions are positive and the coefficients of the co-analytic part of the harmonic functions are negative. We then determine the extreme points, distortion bounds, convolution and convex combination conditions for these functions.

• Korean Journal of Mathematics
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• v.26 no.4
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• pp.747-756
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• 2018

We study a maximum principle for a uniformly elliptic second order differential operator in nondivergence form. We allow a bounded positive zeroth order coefficient in a certain type of unbounded domains. The results extend a result by J. Busca in a sense of domains, and we present a simple proof based on local maximum principle by Gilbarg and Trudinger with iterations.

• Korean Journal of Childcare and Education
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• v.13 no.3
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• pp.83-102
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• 2017

Objective: This study investigates the main effects and interaction effects of mother's reactions to young children's negative emotions on the children's problem behaviors. Methods: A total of 346 mothers with toddlers completed questionnaires, the data were analyzed using Pearson's correlation coefficient and multiple regression. Results: First, mothers' supportive response to young children's negative emotions, including expressive encouragement, emotion-focused reactions, and problem-focused reactions, showed negative relations with the children's internal and external problem behaviors. Mothers' unsupportive response to children's negative emotions, including distress reactions, minimization reactions, and punitive reactions, showed positive relations with the children's internal and external problem behaviors. Second, an interactive effect was observed. For external problem behavior, mothers' lower distress reactions accompanied by higher emotion-focused reactions, lower punitive reactions accompanied by higher emotion-focused reactions, lower distress reactions accompanied by higher problem-focused reactions, and lower punitive reactions accompanied by higher problem-focused reactions all decreased children′s problem behavior. However, for internal problem behavior, only mothers' lower distress reactions accompanied by higher emotion-focused reaction decreased children′s problem behavior. Conclusion/Implication: The main interaction effect on mothers' reaction to young children's negative emotional expression shows that preventive intervention is needed to address problem behavior.

• Economic and Environmental Geology
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• v.20 no.3
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• pp.197-201
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• 1987

Negative induced polarization (IP) responses are examined for a three-layered earth using a digital linear filter method. The negative IP response can occur when the geoelectric section is of type K or Q. The section of type K creates a more pronounced negative effect than that of type Q. For such sections, IP coefficients are determined as a function of the resistivity distribution and the electrode configuration, and only the IP coefficient of the first layer can be negative. As a result, the negative IP response can occur when the first layer is polarizable in the section of type K or Q. and the polarizabilities of the other layers can act to depress the negative response.

• Korean Journal of Human Ecology
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• v.20 no.6
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• pp.1109-1119
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• 2011

The purpose of this study was to examine the difference of the father's and mother's reactions to their children's negative emotions, relations among the children's variables, parent's variables, and parent's reactions. The subjects selected were 183 mothers and 183 fathers with children aged three to five-years-old, from a childcare center and kindergarten in Kwang-ju. Parental emotion-related practices regarding children's negative emotions were assessed with an adaptation of the CCNES(Fabes et al, 1990) that was modified by Kim Hee-Jung(1994). Descriptives, Pearson's correlation coefficient, were used for data analysis by using the SPSS 15.0 program. The results of this study can be summarized as follows: First, fathers and mothers used more positive reactions than negative reactions when their children showed negative emotions. The mothers were significantly higher than fathers on encouragement of expression, punitive, and distress reactions. Second, the children's age and gender, parent's age, level of education and income were negatively and positively correlated to the father's and mother's reactions to their children's negative emotions.

• Journal of the Korean Ceramic Society
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• v.37 no.5
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• pp.432-437
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• 2000

Thermoelectric properties of p-type SiGe alloys prepared by a RF inductive furnace were investigated. Non-doped Si80Ge20 alloys were fabricated by control of the quantity of volatile Ge. The carrier of p-type SiGe alloy was controlled by B-doping. B doped p-type SiGe alloys were synthesized by melting the mixture of Ge and Si containing B. The effects of sintering/annealing conditions and compaction pressure on thermoelectric properties (electrical conductivity and Seebeck coefficient) were investigated. For nondoped SiGe alloys, electrical conductivity increased with increasing temperatures and Seebeck coefficient was measured negative showing a typical n-type semiconductivity. On the other hand, B-doped SiGe alloys exhibited positive Seebeck coefficient and their electrical conductivity decreased with increasing temperatures. Thermoelectric properties were more sensitive to compaction pressure than annealing time. The highest power factor obtained in this work was 8.89${\times}$10-6J/cm$.$K2$.$s for 1 at% B-doped SiGe alloy.

• Journal of Sensor Science and Technology
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• v.18 no.4
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• pp.280-285
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• 2009

In this paper, we designed a 2-stage CMOS operational amplifier with temperature compensation function using 2-poly 4-metal 0.35 $\mu$m standard CMOS technology. Using two bias circuits, the positive temperature coefficient(PTC) and the negative temperature coefficient(NTC) of the bias circuit are canceled out each other. When reference current circuit is simulated that it has a temperature coefficient of -150 ppm/$^{\circ}C$ with a temperature change from 0 $^{\circ}C$ to 120 $^{\circ}C$. Also the proposed circuit has a temperature coefficient of -0.011 dB/$^{\circ}C$ of DC open loop gain with the same temperature range.

• Bulletin of the Korean Mathematical Society
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• v.36 no.4
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• pp.763-770
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• 1999

The purpose of this paper is to give sufficient coefficient conditions for a class of univalent harmonic functions that map each $$\mid$z$\mid$$ = r >1 onto a curve that bounds a domain that is starlike with respect to origin. Furthermore, it is shown that these conditions are also necessary when the coefficients are negative. Extreme points for these classes are also determined. Finally, comparable results are given for the convex analgo.

• Journal of the Korean Data and Information Science Society
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• v.3 no.1
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• pp.65-78
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• 1992

In this paper, we obtain the natural estimators of the coefficient parameters and propose strongly consistent estimators of the parameter in the autoregressive model of order three with non-negative innovations. It is shown that the natural estimators are also strongly consistent for the parameters. We also compare the proposed estimators with the natural estimators and the least square estimators via Monte Carlo simulation studies.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.223-226
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• 2009

Recently, Mining negative association rules has received some attention and proved to be useful. Negative association rules are useful in market-basket analysis to identify products that conflict with each other or products that complement each other. Several algorithms have been proposed. However, there are some questions with those algorithms, for example, misleading rules will occur when the positive and negative rules are mined simultaneously. The chi-squared test that based on the mature theory and Correlation Coefficient can avoid the problem. In this paper, We proposed the algorithm PNCCR based on chi-squared test and correlation is proposed. The experiment results show that the misleading rules are pruned. It suggests that the algorithm is correct and efficient.