• Journal of the Korea Convergence Society
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• v.10 no.5
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• pp.71-78
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• 2019

This study attempted to identify convergent influence on depression and its association with job seeking stress, academic burnout and anxiety among college students. Data collection was carried out using a self-administered questionnaire from Nov. 12, 2018 to Dec. 14, 2018 and the target was randomly selected 304 students from colleges located in J area. Depression was positively correlated with job seeking stress, academic burnout and anxiety. The covariance structure analysis showed that the job seeking stress, the higher academic burnout and the higher anxiety tend to increase depression. These results show that to lower college students' depression, it is necessary to try to lower job seeking stress, academic burnout, and anxiety. These results are expected to be utilized for employment counseling, academic counseling, and expansion of resources for psychological stability and various interventions that lower the depression of college students. In future studies, the survey about additional factors of influence on the depression of college students will be needed.

• Advances in nano research
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• v.13 no.3
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• pp.207-216
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• 2022

In this paper, a novel model is developed for frequency behavior of single walled carbon nanotubes. The governing equation of motion is constructed method based on the Sander theory using Rayleigh-Ritz's method The frequencies enhances on increasing the power law index using simply supported, clamped and clamped free end conditions. The frequency curve for C-F is less than other conditions. It is due to the physical constraints which are applied on the edge of the CNT. It is observed that the C-F boundary condition have less frequencies from the other two conditions. The frequency phenomena for zigzag are insignificant throughout the aspect ratio. Moreover when index of power law is increased then frequencies increases for all boundary conditions. The natural frequency mechanism for the armchair (10, 10) for various values of power law index with different boundary conditions is investigated. Here frequencies decrease on increases the aspect ratio for all boundary conditions. The frequency curves of SS-SS edge condition is composed between the C-C and C-F conditions. The curves of frequency are less significant from small aspect ratio (L/d = 4.86 ~ 8.47) and decreases fast for greater ratios. It is found that the frequencies via aspect ratios, armchair (10, 10) have higher values from zigzag (10, 0). It is due to the material structure which is made by the carbon nanotubes. The power law index have momentous effect on the vibration of single walled carbon nanotubes. The present frequency result is also compared numerically experimentally with Raman Spectroscopy.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.3
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• pp.483-494
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• 2023

Recently, gas turbine generators are widely used for frequency control of power systems. Although the inlet temperature of a gas turbine is a key factor related to the performance and lifespan of the device, the inlet temperature is not measured directly for reasons such as the turbine structure and operating environment. In particular, the inlet temperature of the reheating gas turbine is very important for stable operation management, but field workers are experiencing a lot of difficulties because the manufacturer does not provide information on the calculation formula. Therefore, in this study, we propose a method for estimating the inlet temperature of a gas turbine using a machine learning-based linear regression analysis method based on a polytropic process equation. In addition, by proposing an inlet temperature calculation algorithm through the usefulness analysis and verification of the inlet temperature calculation model obtained through linear regression analysis, it is intended to help to improve the level of reheat gas turbine combustion tuning technology.

• The Journal of the Acoustical Society of Korea
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• v.41 no.6
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• pp.601-609
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• 2022

In August 2007, coastal upwelling occurred off the east coast of Korea, and vertical water temperature and salinity data were obtained from a real-time surface ocean buoy. Based on the time series observation data, a vertical sound velocity structure was calculated before, during, and after the occurrence of the coastal upwelling, and how the coastal upwelling affects the sound propagation and detection environment through acoustic modeling considering the horizontal scale and actual seabed topography. As a result of comparing and analyzing the low-frequency (500 Hz) sound transmission loss and the target detection range by depth using the parabolic equation model, it was analyzed that if coastal upwelling occurs, a detection gain of up to about 10 dB can be expected. In addition, through this study, it was confirmed that the characteristics of sound propagation can be greatly changed even in a short period of about 2 to 3 days before and after coastal upwelling.

• Computers and Concrete
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• v.32 no.1
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• pp.61-74
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• 2023

This article investigates the wave propagation analysis of the imperfect functionally graded (FG) sandwich plates based on a novel simple four-variable integral quasi-3D higher-order shear deformation theory (HSDT). The thickness stretching effect is considered in the transverse displacement component. The presented formulation ensures a parabolic variation of the transverse shear stresses with zero-stresses at the top and the bottom surfaces without requiring any shear correction factors. The studied sandwich plates can be used in several sectors as areas of aircraft, construction, naval/marine, aerospace and wind energy systems, the sandwich structure is composed from three layers (two FG face sheets and isotropic core). The material properties in the FG faces sheet are computed according to a modified power law function with considering the porosity which may appear during the manufacturing process in the form of micro-voids in the layer body. The Hamilton principle is utilized to determine the four governing differential equations for wave propagation in FG plates which is reduced in terms of computation time and cost compared to the other conventional quasi-3D models. An eigenvalue equation is formulated for the analytical solution using a generalized displacements' solution form for wave propagation. The effects of porosity, temperature, moisture concentration, core thickness, and the material exponent on the plates' dispersion relations are examined by considering the thickness stretching influence.

• Korean Journal of Social Welfare Studies
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• v.42 no.1
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• pp.279-304
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• 2011

The housing is basic need to human life, foundation of family life and structural characteristics to control human life and action. The structural characteristics of housing have various effects on the family life such as family lifestyle, relationship of family members and child development and health by family structure. The purpose of the study is to identify how the housing poverty, defined as sub-minimum standard housing conditions, excess housing expenditure and housing instability, affects the family responsibility burden, the family relationship satisfaction and the family life satisfaction. This study used the third Korean Welfare Panel Study, the analytic method used was the Structural Equation Modeling(SEM), and the model fit had a considerable validity by inspecting the SEM. The findings of the study are as follows. Housing poverty had significant positive effect on family responsibility burden, while had significant negative effects on family conflict action method, family relationship satisfaction, family life satisfaction and health(subjective, mental, physical). The indirect effects on housing poverty had better effect by family conflict action method than effect by health, but the direct effects had the most.

• Journal of Microbiology and Biotechnology
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• v.33 no.8
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• pp.1013-1022
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• 2023

Arbuscular mycorrhizal fungi (AMF) are widespread soil endophytic fungi, forming mutualistic relationships with the vast majority of land plants. Biochar (BC) has been reported to improve soil fertility and promote plant growth. However, limited studies are available concerning the combined effects of AMF and BC on soil community structure and plant growth. In this work, a pot experiment was designed to investigate the effects of AMF and BC on the rhizosphere microbial community of Allium fistulosum L. Using Illumina high-throughput sequencing, we showed that inoculation of AMF and BC had a significant impact on soil microbial community composition, diversity, and versatility. Increases were observed in both plant growth (the plant height by 8.6%, shoot fresh weight by 12.1%) and root morphological traits (average diameter by 20.5%). The phylogenetic tree also showed differences in the fungal community composition in A. fistulosum. In addition, Linear discriminant analysis (LDA) effect size (LEfSe) analysis revealed that 16 biomarkers were detected in the control (CK) and AMF treatment, while only 3 were detected in the AMF + BC treatment. Molecular ecological network analysis showed that the AMF + BC treatment group had a more complex network of fungal communities, as evidenced by higher average connectivity. The functional composition spectrum showed significant differences in the functional distribution of soil microbial communities among different fungal genera. The structural equation model (SEM) confirmed that AMF could improve the microbial multifunctionality by regulating the rhizosphere fungal diversity and soil properties. Our findings provide new information on the effects of AMF and biochar on plants and soil microbial communities.

• The Journal of the Korea institute of electronic communication sciences
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• v.19 no.1
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• pp.241-248
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• 2024

Socially, organizations are required to effectively manage their information resources, both in terms of acquiring information from external sources and safeguarding against potential breaches by insiders. While information security policies and technologies implemented by organizations contribute to achieving internal security, an overly complex or disorganized security structure can create uncertainty among employees. In this study, we identify factors of structural information security (IS)-related uncertainty within organizations and propose that they contribute to non-compliance. We develop a research model and hypotheses based on previous studies on the information security environment and test these hypotheses using structural equation modeling. Our findings indicate that uncertainties related to IS policy, technology, and communication decrease employees' IS role identity and their intention to comply with IS measures. By addressing these uncertainties, organizations can improve their IS environment and work towards achieving there is goals.

• Management & Information Systems Review
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• v.30 no.2
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• pp.57-79
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• 2011

One of the fastest growing sector in tourism industry is MICE industry due to globalization among the countries in various parts including business, politics, and cultural exchange. The objectives of this research can be in two fold: firstly, to evaluate the convention service quality and categorize them into three groups, basic service, performance service and exciting service; secondly, to provide the exciting service as a recovery program to restore customer satisfaction and their intention to reuse when the basic or performance service failure occurs. The results are as follows: among the four dimensions of the service quality, only the availability of information and the employee's performance were effected by the exciting service quality. Secondly, employees's performance can only be effected by the exciting service when customer service factor is included prior to the events. Thirdly, the following dimensions of services were not selected to be effective by the exciting services: conditions of physical facility, related infra-structure, the process of customer service and the program. Fourthly, only the additional services and events were selected to be the effective exciting services for the recovery program.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.4
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• pp.2160-2169
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• 2014

The purpose of this research was to investigate the relation between social support and the knowledge of drug which affects drug abuse in elderly by using structure equation model(SEM). The samples included 177 elderly who lived in 'D' city was selected. Data were collected and analyzed using questionnaires for 13 days from May 13 to May 25, 2013. 3 factors of research models had a significant model fit and correlation. The key research findings are as follows. First, the more social support they have, the more knowledge of drug they tend to have(${\beta}$=.515, p=.005). Second, direct effect that social support led to drug abuse was significant.(${\beta}$=-.769, p=.002) However the indirect effect was not significant(${\beta}$=.036, p=.671). Third, the indirect effect that social support led to drug abuse was not significant, which means it has no mediating effect. Social support turned out to be very important factor in this research, but other preceding research mentioned that knowledge of drug is an important factor which could reduce drug abuse. Research needs to be analyzed repeatedly for verification of effects.