• Transactions on Electrical and Electronic Materials
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• v.10 no.4
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• pp.121-124
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• 2009

In this study, in order to develop compositions of ceramics suitable for piezoelectric actuator and ultrasonic vibrator applications using low temperature sintering, multilayer, PMN-PNN-PZT ceramics were fabricated using $Li_2CO_3$ and $Na_2CO_3$ as sintering aids. Their structural, piezoelectric and dielectric characteristics were investigated according to the Zr/Ti ratio. As the Zr/Ti ratio increased, the electromechanical coupling factor $k_p$, and piezoelectric constant $d_{33}$ and the mechanical quality factor $Q_m$ all increased with Zr/Ti ratio and then decreased after the ratio exceeded 50/50. At the ratio of Zr/Ti =49/51 and sintering temperature of $900^{\circ}C$; the density, electromechanical coupling factor $k_p$, dielectric constant ${\varepsilon}_r$ piezoelectric $d_{33}$ constant and mechanical quality factor $Q_m$ all showed the optimum values of 7.900 $g/cm^3$, 0.576, 856, 312 pC/N, 1,326, respectively. These property values are very suitable for multilayer ceramics actuator applications.

• New & Renewable Energy
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• v.7 no.2
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• pp.28-35
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• 2011

Recently, photovoltaic systems have been devolved into much larger systems up to MW-scale. Photovoltaic industry participants give their focus on power generation capability of photovoltaic modules because their benefits can be decided from the amount of generation. The information on long-term performance change of photovoltaic modules helps to estimate the amount of power generation and evaluate the economic cost-benefits. Long-term performance of a PV system has been analyzed with operation data for 12 years from 1999 to 2010. In the first year, the amount of yearly power generation was 57.7 MWh with 13.2% capacity factor. In 2007, the amount of yearly generation was 44.3 MWh with 10.14% capacity factor, and in 2010, the amount was decreased down to 38.1 MWh with 8.7% capacity factor. The result means that long-term capacity factor has been 4.5% decreased for 12 years and that the amount of generation has been decreased 34.0% for 12 years which is 2.8 % per year. The latter capacity factor has been decreased faster than 0.20%, the average rate for 10 years. The performance decrease of the PV system is meant to be accelerated. The decrease of performance and utilization is due to aged deterioration of photovoltaic modules and lowering conversion efficiency of PCS.

• The Korean Journal of Applied Statistics
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• v.13 no.2
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• pp.427-436
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• 2000

In this paper, we consider a Bayesian model selection problem of lifetime distributions using fractional Bayes factor with noninformative prior when type II censored data are given. For a given type II censored data, we calculate the posterior probability of exponential, Weibull and lognormal distributions and select the model which gives the highest posterior probability. Our proposed methodology is explained and applied to real data and simulated data.

• Korean Journal of Child Studies
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• v.19 no.2
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• pp.97-113
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• 1998

The purpose of this paper was to evaluate hypothesized alternative models for the factor structure of the Korean Version of the Aberrant Behavior Checklist(K-ABC) using standardized samples. Confirmatory factor analyses of correlated factor models using the Jeroskog method were carried out. Analyses supported the two-factor processing model. When the achievement scale was added, a three factor model (two processing factors and an achievement factor) emerged. When factorially uncorrelated models were analyzed, fit indices proved to be improper.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.2
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• pp.93-100
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• 1998

In this paper we analyze the effect of nonlinear gain on laser modulation characteristics applying a small-signal analysis to the rate equation which includes a nonlinear gain term. Also we analyze the resonance frequency and the damping factor which determine laser modulation characteristics, define K factor which is the proportionality factor between resonance frequency and damping factor, and conclude that the decrease in K factor is due to increases in differential gain and no correlation between K factor and nonlinear gain is identified.

• Korean Journal of Biological Psychiatry
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• v.18 no.3
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• pp.126-133
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• 2011

Objectives The Beck Depression Inventory (BDI) is one of the most widely used self-report measures of depression in both research and clinical practice. The Beck Depression Inventory Second Edition (BDI-II) is the most recent version of the BDI. Validity of the BDI-II has been documented in other countries. This study examined the factor structure of the Korean version of BDI-II in a large sample of university students. Method Data were obtained from 2,529 students of Kongju National University. The factor structures of the Korean version of BDI-II were assessed using exploratory and confirmatory factor analysis. Results A high level of internal consistency and reliability (Cronbach's ${\alpha}$ = 0.91) and item homogeneity was confirmed. Exploratory factor analysis showed a two-factor structure (cognitive and somatic-affective), which was almost identical to the original model demonstrated by Beck et al. The following confirmatory factor analysis also supported the two-factor structure (cognitive and somatic-affective) is a better fit than the other two-factor structure (cognitive-affective and somatic). The higher mean score for women compared to men is consistent with the results of previous reports. Conclusion These data support the reliability and concurrent validity of the Korean version of BDI-II as a measure of depressive symptoms in nonclinical samples.

• Journal of the Korean Society of Clothing and Textiles
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• v.33 no.8
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• pp.1262-1272
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• 2009

The study is classifies the figures of obese women aged 20-50 with an over 25 BMI from the data of the fifth Size Korea in 2005. As the result of conducting the factor analysis for segmenting the shape, Factor 1, Factor 2, Factor 3, and Factor 4 are respectively derived as the factor on a volume, the factor on the size of the vertical direction, the factor on the shoulder region, and the factor on the body length balance. As the result of conducting the cluster analysis using 4 factors (scores extracted from the analysis of factor analysis) the body type of obese women was classified into four types. The name of shape was specified by combining 'P' (an abbreviation of petite) that indicated the height (smaller than 155cm) among the height names of KS standard, 'R' (abbreviation of regular) that indicated the height (155cm-165cm) and the body characteristics. Type 1 had the longest length, and normal circumference, thickness, and width but with the developed shoulder. Type 1 was classified as a robust, 'Plus-RH'. Type 2 had the middle height, the shortest length of the upper part, a relatively-long length of the lower part of body. Type 2 shows the characteristics of a small body that was classified as 'Plus-PI'. The most obese body was Type 3 that had the normal length and shoulder size but showed the longest length of the upper part of the body; it was classified as 'Plus-PO'. Type 4 as the small shape had a potbelly and showed the characteristics of the shortest body classified as 'Plus-Pb'.

• Korean Journal of Occupational Health Nursing
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• v.8 no.2
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• pp.212-220
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• 1999

This study was designed to determine anxiety factors and levels of anxiety of foreign industrial workers. One hundred and seventy five workers were researched who were working in Guro Working Complex, Ansan City and Sungnam City Working Complex asking 60 questionnaires from Feb. 25, 1996 to April 12, 1996. The results were as follows ; 1. The 30.3% of foreign workers were from Nepal. 17.7% from Bangladesh 10.9% from Srilanka, 14.9% from Philippines, 1.1% from Ghana. 80% of foreign workers were male, 77.7% were single and most of then were in the age from 25 to 34. 37.1% of foreign workers had not lived in Korea less than 12 months, 58.8% graduated from college, 33.7% from highschool, and more than half lived in a dormitory. 2. On the anxiety level related to subject workers' general characteristics, the workers level from Nepal recorded the highest point 2.70 statistically showing a significant difference(P=0.0003). On the physical anxiety level, the workers from Nepal recorded a significantly low point comparing with Jamaica, Burma, Vietnam and Nigeria(P=0.01). 3. Emotional anxiety level marked the highest on the workers living as a tenant comparing with the workers in dormitory. 4. On anxiety factors, the emotional anxiety recoded the highest, the social anxiety and the somatic anxiety. 5. On the relation between the anxiety factor, the somatic anxiety factor had a relation with emotional, environmental, and occupational factors and on the other relation between the anxiety factor and emotional factor had a relation with environmental, social, cultural factors. Moreover, the environmental factor had a relation with the cultural factor, social factor had a relation with the cultural factor, and cultural factor was related to the occupational factor.

• Journal of the Ergonomics Society of Korea
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• v.28 no.1
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• pp.21-27
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• 2009

The purpose of this research is to understand the physiological characteristics of muscular men between the ages of 20 and 34 years who are distinct from the general population due to their muscular development, and to categorize them according to upper body somatotypes. This research was conducted in order to provide basic data necessary for developing clothing products for muscular men. The research method and results were as follows: 1. The study carried out factor analysis with the body measuring value of 168 muscular men according to the body classification method of Sheldon and Heath-Carter. The study materialized muscular men's lower body types statistically by carrying out cluster analysis, regarding scores of each factor extracted from the factor analysis as an independent variable. The study also carried out discriminant analysis with the results of cluster analysis classified so that morphological characters of each type were remarkably distinguished. 2. As the results of factor analysis, the study set up number of factors as three. Factor 1 occupied 38.149% of the total variables as a size factor of the lower body. Factor 2 occupied 20.417% of the total variables as a height and length factor of the lower body. Factor 3 occupied 8.466% of the total variables as a length factor of the hip. 3. The study classified the lower body type into three types and the characteristics by each type were as follows. Type 1 was a group with the best developed muscle in the lower of the body, considering that a size of their lower bodies was the largest. Type 2 was well-balanced muscular males though a size of the lower body was smaller than other types. This type didn't have fatness of the abdomen and large hips. Type 3 was a body type that the length from the waist to the hip was long. 4. As the results of carrying out discriminant analysis to distinguish muscular men's lower body types, the discriminant accuracy was 86.3% over all in the lower bodies.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07b
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• pp.650-652
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• 2002

In this paper, specimens was manufactured in general method annexing PAN-PZT+0.8wt%Mn+1wt% Nb ceramics doped by Sr(0.0 ~ 1.2 wt%). and the following conclusion has been deduced. In XRD, the crystal structure of ceramic has the rombohedral structure and consequently the specimen characterized by MPB was manufactured. According to dopping with Sr, electromechanical factor(kp) little is changed. kp was maximum value 31.31[%] at Sr 1.2[wt%]. mechanical quality factor(Qm) was maximum value 371.879 at Sr 0.6[wt%].