• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.05a
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• pp.37-40
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• 2000

LLDPE using power cable is used in electric insulators or dielectric materials because it is excellent in thermal properties or friendly environment but has defects of tree and accumulation of space charges. For the reason of that, it is blended with EVA to complement those problems. In this study, We made LLDPE/EVA samples that mixture ratio was 50:50, 60:40, 70:30, 80:20[W%] and studied physical and dielectric characteristics. We investigated the frequency and temperature dependency of tan 0 for mixtured samples in the temperature range of 25~110$[^{\circ}C]$, frequency range of $20{\sim}1\times10^6$ [Hz].

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.2
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• pp.161-168
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• 2015

An experimental study was conducted to scrutinize the influence of the frequency of an ultrasonic standing wave on the variation in the behavior of a methane-air premixed flame. The evolutionary features of the propagating flame were captured by a high-speed camera, and the macroscopic flame behavior, including the flame structure and local velocities, was investigated in detail using a post-processing analysis of the high-speed images. It was found that a structural variation and propagation-velocity augmentation of the methane-air premixed flame were caused by the intervention of the ultrasonic standing wave, which enhanced the combustion reaction. Conclusive evidence for the dependency of the flame behaviors on the driving frequency of the ultrasonic standing wave and equivalence ratio of the reactants is presented.

• Journal of Digital Convergence
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• v.17 no.4
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• pp.365-379
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• 2019

The purpose of this study is to investigate what factors affect cyber-delinquency after examining the previous research focusing on the general strain theory and the delinquency opportunity theory in the existing studies. And as adolescents move from middle school to high school, this study is intended to analyze what factors affect cyber-delinquency from a longitudinal perspective using KCYPS(Korea Child and Youth Panel Survey) elementary 4th grade fourth and seventh data. The adolescence cyber-delinquency probability of occurrence were analyzed through the panel logit fixed-effect model using STATA. And then the cyber-delinquency frequency of adolescents were analyzed through the panel tobit random-effect model. As a result of analyzing the factors affecting cyber-delinquency frequency, Adult media commitment, computer use time, and cell phone dependency increased cyber-delinquency frequency. On the other hand, among the parenting attitudes, the attitude of supervising attentively and adolescents' age-increasing decreased cyber-delinquency frequency.

• Journal of the Korean Society of Clothing and Textiles
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• v.29 no.5 s.142
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• pp.715-726
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• 2005

The purpose of this study was to identify the effects of the sensation seeking and body image on female adolescents' clothing behavior and hair style attitude. The data was collected from 390 high school girls living in Seoul, via a self·administered questionnaires, and were analyzed by frequency, factor analysis, reliability test, Pearson's correlation, and multiple regression. The results of this study was as follows : 1) Three factors of body images were self appearance evaluation, appearance orientation and fitness orientation. Five factors of clothing attitudes were fashion/clothing interest, clothing exhibition, social approval, psychological dependence on clothing and fashion leadership. And three factors of hair style attitudes were interest in hair style, individuality in hair style and dependency on hair designer. 2) As the result of analyzing the effects of sensation seeking and body image on clothing behavior, fashion/clothing interest was explained by appearance orientation and fitness orientation, and clothing exhibition by sensation seeking and appearance orientation, and social approval by appearance orientation, self appearance evaluation and body cathexis, and fashion leadership by appearance orientation, fitness orientation and self appearance evaluation, and clothing conformity to the self-entertainer by appearance orientation, sensation seeking and fitness orientation, and appearance related delinquency by sensation seeking, appearance orientation, fitness orientation, self appearance evaluation. 3) As the result of analyzing the effects of sensation seeking and body image on hair style attitudes, interest in hair style was explained by the factors such as appearance orientation, sensation seeking, fitness orientation, and body cathexis, and individuality in hair style by appearance orientation, sensation seeking and self appearance evaluation, and dependency on hair designer by body cathexis.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.9
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• pp.73-84
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• 2004

This paper suggests a new scalar multiplication algerian to resist SPA which threatens the security of cryptographic primitive on the hardware recently, and discusses how to apply this algerian Our algorithm is better than other SPA countermeasure algorithms aspect to computational efficiency. Since known SPA countermeasure algorithms have dependency of computation. these are difficult to construct parallel architecture efficiently. To solve this problem our algorithm removes dependency and computes a multiplication and a squaring during inversion with parallel architecture in order to minimize loss of performance. We implement hardware logic with VHDL(VHSIC Hardware Description Language) to verify performance. Synthesis tool is Synplify Pro 7.0 and target chip is Xillinx VirtexE XCV2000EFGl156. Total equivalent gate is 60,508 and maximum frequency is 30Mhz. Our scalar multiplier can be applied to digital signature, encryption and decryption, key exchange, etc. It is applied to a embedded-micom it protects SPA and provides efficient computation.

• Polymer(Korea)
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• v.31 no.4
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• pp.302-307
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• 2007

The resistive-type humidity sensors were prepared from the copolymers of [2-[(methacryloyloxy)ethyl]dimethyl]propylamonium bromide (MEPAB), [2-[(methacryloyloxy)ethyl]-2-hydroxyethyl]dimethylammonium bromide (MEHDAB), 2- [(methacryloyloxy)ethyl]trimethylammonium chloride (METAC), and n-butyl methylacrylate (MBA). Four component copolymers MEPAB/BMA/MEHDAB/METAC=4/4/1/1, 3/5/1/1, 2/6/1/1, 1/7/1/1 crosslinked with blocked-isocyanate on Ag/Pd electrode/alumina substrate showed a good durability at high humidities. The various electrical properties such as frequency dependency, temperature dependency, hysteresis, response time and water durability were examined. In the case of copolymer composed of MEPAB/BMA/MEHDAB/METAC=2/6/1/1, the resistance varied from $1.4\;M{\Omega}$ to $2.9\;k{\Omega}$ at $25^{\circ}C$ in the range of $30{\sim}90\;%RH$ and this copolymers showed a good linearity and low hysteresis.

• Child Health Nursing Research
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• v.10 no.1
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• pp.37-47
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• 2004

Purpose: This study aimed to identify the alcohol drinking pattern of parents and to analyze drinking related factors in problem drinking among adolescent's parents. Method: This study was conducted through a structured questioning from November 5th to 22th in 2002. Those are 2,522 parents of the students of the 1st and 2nd grade who were selected randomly among 26 middle and high schools located in Socho-gu, Seoul. Data was analyzed using SAS program that included descriptive statistics, Chi-square test, and multiple logistic regression analysis. Result: 1. For frequency of drinking, 33.1％ of the subjects responded to drink two-four times a month, 26.0％ drink more than two times a week. 2. For the amount of drinking, 29.6％ drink one or two glasses while 9.4％ drink over ten glasses at a time. 3. The mean AUDIT score was 8.27 7.02(score of range: 0- 40). 4. Based on AUDIT score, drinkers with less than eight point from AUDIT(normal group) were 55.1％, from more than eight point to less than twelve point from AUDIT(problematic drinker) were 16.3％, and more than twelve point from AUDIT(alcohol abuse and dependency) were 28.6％. 5. Based on more than twelve point from AUDIT, female(mother), high school and, have religion, housekeeper were the significantly higher score than counter parts. Conclusion: Alcohol drinking pattern and level of drinking of their parents links to their children's drinking and results in family, social, and national loss. Active prevention is needed. Specially, pertinent education about drinking and public education for mothers who are housekeepers should be carried out with concentrated intervention programs for the problematic drinker so alcohol abuse and dependency can be reduced.

• Journal of the Korean Society for Nondestructive Testing
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• v.22 no.2
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• pp.193-197
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• 2002

The frequency dependency of the Rayleigh surface wave was investigated indirectly by measuring the angular dependency of the backward radiation of the incident ultrasonic wave in the abrasion specimens, which was explained in view of the residual stress distribution. The peak intensity of the backward radiation profile decreased and the right half width of the profile increased with an increase of the variational rate of residual stress for the scuffing specimen. The peak intensity was also affected by the surface wave scattering during the propagation around the micro-damages. The peak angle might depend on not only the amount of residual stress but also the micro-structure. The result observed in this study demonstrates the high potential of the backward radiated ultrasound as a tool for the nondestructive evaluation of the subsurface gradients of materials.

• Journal of the Korean Society for Nondestructive Testing
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• v.20 no.5
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• pp.397-401
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• 2000

The corrosion-fatigue characteristics of the 12Cr steel, which is widely used in fossil power plants as a turbine blade material, are evaluated nondestructively by use of the Rayleigh surface wave. In this study, the frequency dependency of the Rayleigh surface wave is investigated indirectly by measuring the angular dependency of the backward radiation of the incident ultrasonic wave in the aged specimens, and then compared to the corrosion-fatigue characteristics. The width of the backward radiation profile decreases as the increase of the aging temperature, which seems to result from the increase of the effective degrading layer thickness. This parameter also shows an inversely proportionality to the exponent, m, in the Paris law which predicts the crack size increasement due to fatigue. The result observed in this study demonstrates high potential of the backward radiated ultrasound as a tool for the nondestructive evaluation of the corrosion-fatigue characteristics of the aged materials.

• Polymer(Korea)
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• v.31 no.3
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• pp.194-200
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• 2007

The resistive-type polymeric humidity sensors were prepared from the copolymers of [2- [(methacryloyloxy)ethyl] dimethyl] propylammonium bromide(MEPAB), [2- [(methacryloyloxy)ethyl]-2-hydroxyethyl]dimethylmonium bromide (MEHDAB), n-butyl methylacrylate(MBA), 2-hydroxyethyl methylacrylate(HEMA) and styrene. Four kinds of copolymers, ie, MEPAB/styrene/MEHDAB MEHDAB/BMA/HEMA, MEPAB/BMA/MEHDAB, and MEPAB/styrene/HEMA crosslinked with blocked-isocyanate on the Ag/Pd electrode/alumina substrate showed good durability at high humidities. The various electrical properties such as frequency dependency, temperature dependency, hysteresis, response time and water durability were examined. In the case of copolymer MEPAB/BMA/MEHDAB= 3/6/1, the resistance was varied from $2.9 M{\Omega}$ to $1.84k{\Omega}$ at $25^{\circ}C$ in the range of $30{\sim}90%RH$ and this copolymers showed a good linearity and low hysteresis.