• Journal of the Korean Magnetics Society
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• v.9 no.3
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• pp.136-142
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• 1999

$Ni_{0.65}Zn_{0.35}Cu_{0.3}Fe_{1.7}O_4$ has been studied with x-ray diffraction, Mossbauer spectroscopy, and vibrating sample magnetometer. The crystal structure is found to be a cubic spinel with the lattice constant $a_0=8.403{\AA}$. Mossbauer spectra of have been taken at various temperatures ranging from 12 K to 665 K. as the temperature increases toward $T_N$ a systematic line broadening effect in the Mossbauer spectrum is observed and interpreted to originate from different temperature dependencies of the magenetic hyperfine fields at various iron sites. Also, by using binomial distribution equation we obtained the hyperfine fields of tetrahedral[A] and octahedral sites[B], $H_{hf}(A)=470\;kOe,\; H_{hf}(B0)=495 \;kOe,\; H_{hf}(B1)=485\;kOe, \;H_{hf}(B2)=453\;kOe,\; H_{hf}(B3)=424\;kOe,\; H_{hf}(B4)=390\;kOe,\; H_{hf}(Bavr)=451\;kOe$ respectively at room temperature. The isomer shift indicates that the iron ions are ferric at tetrahedral[A] and octahedral sites[B], respectively. The Neel temperature is determined to be $T_N=665\;K$. The results of the VSM data gave the magnetic moment and coercivity values of $M_S=66\; emu/g\;and\;H_C=36\;Oe$.

• Journal of the Korean Applied Science and Technology
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• v.35 no.4
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• pp.1057-1072
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• 2018

In this study, micro-sized $CeO_2$ particles were synthesized by spray pyrolysis, and EG(ethylene glycol) and CA(citric acid) as organic additives were added to obtain hollow and porous particle during spray pyrolysis, and characteristics of obtained ceria were investigated according to the amount of added organic additives. Spray pyrolysis, postheat and ball-milling were combined to give 6 paths. $CeO_2$ nano-sized particle was obtained by the path which has sequence of Spray Pyrolysis with 0.5 M of EG and CA${\rightarrow}$Post-heat${\rightarrow}$Ball-milling${\rightarrow}$Post-heat among 6 paths. The average particle size(24 nm with standard deviation of 3.8 nm) of $CeO_2$ nano-sized particle by TEM analysis is close to the primary particle size(20 nm) which was calculated by Debye-Scherrer equation. To investigate the morphological characteristics and structure of the synthesized nanoparticle powders, SEM(Scanning Electron Microscopy), XRD(X-Ray Diffractometer) and TEM(Transmission Electron Microscopy) were used.

• Journal of Convergence for Information Technology
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• v.8 no.6
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• pp.293-303
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• 2018

The purpose of this study is to explore the effect of burden of caring unmarried adult children on depression of employed women and to verify the mediating effects of couple communication and job satisfaction. For the purpose, the data from the fourth year Korean Longitudinal Survey of Women and Families on 586 employed women with baby boomer husbands and unmarried adult children were analyzed by using structure equation modeling. The found results are as follows. First, burden of caring unmarried adult children of employed women had a positive effect on their depression, while it had a negative effect on couple communication and job satisfaction. Second, couple communication of employed women influenced negatively on their depression and had a partial mediating effect on the relationship between burden of caring unmarried adult children and depression. Third, the effect of burden of caring unmarried adult children on depression of employed women was partly mediated by their job satisfaction. Further, the practical programs to enhance couple communication and job satisfaction, as well to reduce depression, were presented.

• The Journal of the Korea Contents Association
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• v.18 no.11
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• pp.353-368
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• 2018

The purpose of this study is to examine the effect of private tutor's job stress on the organizational commitment and turn-over intention and to verify the mediating effect of the organizational commitment. The questionnaire survey was peformed for 332 private tutors in special education region in Seoul. The collected data were used as a model of path coefficients obtained through analysis of structure equation model(SEM) and hypothesis verification. The result of the verification is as follows. First, both stress by student and stress by administrative support showed statistically significant negative effects on the organizational commitment. Second, the private tutor's organizational commitment showed a statistically significant negative effects on the turn-over intention. Third, both stress by task and stress by conflict in organization showed statistically significant positive effects on the turn-over intention. Fourth, even if both stress by student and stress by administrative support showed statistically no significant effects on the turn-over intention, they showed statistically significant effects on the turn-over intention with the mediating effect of the organizational commitment. It was confirmed that the turn-over intention can be decreased by relief of the private tutor's job stress and enhancement of the organizational commitment. In this process, it is meaningful to verify the role and function of the private tutor's organizational commitment.

• 한국노년학
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• v.37 no.3
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• pp.527-547
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• 2017

The purpose of this study is to investigate how depression, death anxiety, and social support can exert influence on the psychological well-being of elderly living alone through a parameter of resilience. A survey was conducted involving 988 elderly over the age of 65 living alone in the Daejeon metropolitan area and Chungcheongnam-do and the data were analyzed using structure equation model. The results were as follows. First, in the measurement of variables according to demographic characteristics, depression showed significant differences depending on gender, level of education, health, and financial condition, while death anxiety differed depending on gender, and level of education. Social support was significantly different by gender, age, level of education, region, health, and financial condition. The level of resilience was significantly different by gender, age, level of education, health, and financial condition. Psychological well-being varied according to gender, level of education, health, and financial condition. Second, the effects of depression, death anxiety and social support on psychological well-being were examined. It was found that depression had a negative influence and social support had a positive impact while death anxiety showed no influence. Third, with regard to the effects of depression, death anxiety, social support on resilience, depression was found having negative influence, whereas social support having positive influence. Forth, psychological well-being was positively affected by resilience. Also, through the mediated pathway of resilience, their psychological well-being seemed to totally improve when the negative factors were reduced and the positive ones promoted. This study may have some significance in reference to examine the factors affecting the psychological well-being of elderly living alone and to develop social welfare service programs and policies in the field.

• Management & Information Systems Review
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• v.38 no.2
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• pp.29-46
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• 2019

O2O services, a form of mobile commerce, are increasing due to the widespread use of smartphones and the rational consumption trend of young consumers. In addition, the introduction of Social Commerce's O2O service has transformed customer experience into innovation. Therefore, the purpose of this study is to investigate the effect of O2O service characteristics and social commerce provider characteristics on the social commerce 's O2O service as a social psychological image that consumers have at the point of purchase and use time, as a smart shopper feeling and a cheapness shopper feeling. And the relationship between consumer satisfaction and intention to use through Structure Equation Modeling, and to suggest the implications for O2O service management that can provide greater satisfaction to consumers by identifying the process of creating satisfaction of O2O service. The results of the study show that price discounts and scarcity of social commerce's O2O service characteristics have shown that it increases smart shopper feeling. Also, it was confirmed that brand awareness and ease of purchase, which are characteristics of social commerce, confirms the increase of cheapness shopper feeling. We also confirmed the effect of smart shopper feeling and cheapness shopper feeling on satisfaction. This satisfaction has a positive effect on the intention to use. The result of this study is that it is necessary to reduce the cheapness shopper feeling of consumers and to emphasize the price discount and scarcity so that the smart shopper feeling occurs in order to satisfy the consumers who purchase O2O service products.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.32 no.2
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• pp.87-92
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• 2019

In this paper, we have verified a low-voltage EM(elasto-magnetic) sensing technique for tensile force management of PSC(prestressed concrete) internal tendon in order to apply the technique to actual construction sites where stable power supply is difficult. From observation of past domestic and overseas PSC structural accident cases, it was found that PS tension is very important to maintain structural stability. In this paper, we have tried to measure the tensile force from a magnetic hysteresis curve through EM sensors according to voltage value by using relation between magnetostriction and stress of ferromagnetic material based on elastic-magnetic theory. For this purpose, EM sensor of double cylindrical coil type was fabricated and tensile force test equipment for PS tendon using hydraulic tensioning device was constructed. The experiment was conducted to confirm relationship between changes of permeability and tensile force from the measurement results of the maximum / minimum voltage amount. The change of magnetic hysteresis curve with magnitude of tensile force was also measured by reducing amount of voltage step by step. As a result, the slope of estimation equation in accordance with magnitude of magnetic field decreases with the voltage reduction. But it was confirmed a similar pattern of change of magnetic permeability for the magnetic hysteresis loop. So, in this study, it is considered that it is possible to manage the tensions of PSC internal tendon using EM sensing technique in low-voltage state.

• Geophysics and Geophysical Exploration
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• v.24 no.3
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• pp.89-97
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• 2021

Fault detection in seismic data is well suited to the application of machine learning algorithms. Accordingly, various machine learning techniques are being developed. In recent studies, machine learning models, which utilize synthetic data, are the particular focus when training with deep learning. The use of synthetic training data has many advantages; Securing massive data for training becomes easy and generating exact fault labels is possible with the help of synthetic training data. To interpret real data with the model trained by synthetic data, the synthetic data used for training should be geologically realistic. In this study, we introduce a method to generate realistic synthetic seismic data. Initially, reflectivity models are generated to include realistic fault structures, and then, a one-way wave equation is applied to efficiently generate seismic stack sections. Next, a migration algorithm is used to remove diffraction artifacts and random noise is added to mimic actual field data. A convolutional neural network model based on the U-Net structure is used to verify the generated synthetic data set. From the results of the experiment, we confirm that realistic synthetic data effectively creates a deep learning model that can be applied to field data.

• Journal of Christian Education in Korea
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• v.64
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• pp.173-202
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• 2020

This study was conducted in order to investigate the structural relationship bewteen the learning participation motive effect on servant leadership in the church family ministry program and the sense of community. First, analyizing previous studies, a structural model was developed. Then, in the effort of verifying the structural model, 607 responses out of 700 questionnaires distributed into nationwide churches and institutes participating in church family ministry program were collected as target data. Informations on learning participation motive, servant leadership, and sense of community were collected through the questionnaires after the church family ministry program. In order to study the structural relationship between the servant leadership effect on learning participation motive and the sense of community, the collected data were analyzed according to structure equation model analylsis. As a result, the structural model this study suggested was found proper. Accordingly, it was verified that the sense of community carrying the effect of intrinsic and extrinsic motives, two of learning participation motives, affected servant leadership. Also, it was verified that the subfactors of the sense of community played important role in enhancing servant leadership in cause and effect relationship between learning participating motive and servant leadership. Therefore, in church family ministry program, it can be suggested that moderating sense of community under the consideration of participants' intrinsic and extrinsic motives makes moderating the level of learning participation motive possible.

• Journal of the Society of Disaster Information
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• v.18 no.1
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• pp.228-240
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• 2022

A comprehensive safety management system will be required in accordance with the implementation of the Major Disaster Punishment Act for close-up safety management of construction sites. Safety management level evaluation management requires a comprehensive relationship between safety management under the Construction Technology Promotion Act and health and health management system under the Industrial Safety and Health Act. Purpose: Safety under the Serious Accidents Punishment Act. The ultimate goal is to study the comprehensive analysis and relationship of health management and to improve the safety evaluation level of health and health management. Methods: The feasibility of the questionnaire was confirmed through the second Delphi analysis of construction site experts and safety managers, and the regression coefficient and path analysis of potential variants in safety management, safety management, health management and safety inspection were confirmed. Result and Conclusion: In the structural model, the regression coefficient (89%) from safety management, health system, and safety management to safety inspection execution and lambda values of appropriate observation variables were confirmed. In the path analysis, the total effect (.809) was confirmed by mediating health hygiene in the relationship between health plan establishment adequacy and post-inspection management, and the path coefficient (.82) of temporary structure safety was confirmed.