• Journal of the Korean Society of Safety
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• v.34 no.6
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• pp.58-64
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• 2019

Over the past decades there has been a growing body of researches that examines the psychological traits related to safety outcomes. After briefly reviewing the relationships between psychological dispositions and safety outcomes, we empirically examine the relationships with 2 samples of 1,102 participants. Fifteen psychological dispositions (big 5 personality, locus of control, cognitive failure, affection from job and relations, 4 achievement goal orientations, self-efficacy, fatigue, and depression) and four psychological outcomes (safe behavior, unsafe behavior, accidents, and injuries) are examined. After covariance structure modeling variances of safety outcomes are well explained by simple 4 dispositions of consciousness, mastery-approach goal orientation, self-efficacy, and depression. We name them 'core safety disposition', and name four psychological outcomes 'safety consciousness', and the relationships between those latent variables are stronger than between measurement variables. We propose core safety disposition as a cause of safety consciousness, and discuss implications for research and practices.

• Journal of Preventive Medicine and Public Health
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• v.33 no.4
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• pp.426-435
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• 2000

Objectives : To determine the relationships among quality, satisfaction, value and purchase intention in health care service. Methods : The data were gathered from out-patients who had used hospital services. They were asked to assess service quality, satisfaction, service value, and purchase intention. A total of 557 usable questionnaires were gathered. The data were analyzed using SAS version 6.12. The analysis methods employed in the study were confirmatory analysis and covariance structural analysis. Results : Service quality exhibited a significant and positive relationship with satisfaction, service value, and purchase intention. Furthermore, satisfaction had a significant and positive relationship with purchase intention. And finally, service value had a significant and positive relationship with both satisfaction and purchase intention. Based on these findings, it is evident that satisfaction was a mediator between service quality and purchase intention. Also service value played a mediating role between service quality and satisfaction. Conclusions : These results suggest that service quality is an antecedent of satisfaction and sonics value, and exerts a stronger influence on purchase intentions than satisfaction and service value do. Thus, managers may need to emphasize service quality in health care.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.2
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• pp.555-562
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• 2021

This study aims to understand the effect of millennial transformational leadership (MTL) on organizational performance in Indonesian Fishery startups. The population of this study included select fishery startups in Indonesia based on the data released by the Ministry of Marine Affairs and Fisheries of the Republic of Indonesia and Digital Fishery Network. This study used the statistical method of PLS-SEM to analyze the data. The findings show that the MTL has no direct positive relationship with organizational performance; MTL has a direct positive relationship with organizational agility; MTL has a direct positive relationship with IT capability; IT capability has a direct positive relationship with organizational agility; organizational agility has a direct positive relationship with organizational performance in fishery startups in Indonesia during this pandemic era. It is suggested that future researches use covariance-based-structural equation modeling which is able to test the research model's feasibility. Roles of mediating variables in addition to the main variables-for example, organizational agility as a mediating variable on the relationship between MTL and organizational performance - are also suggested to be examined. In spite of the limitations, the model developed is still interesting to investigate and is expected to enhance the literature on transformational leadership.

• Nuclear Engineering and Technology
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• v.54 no.4
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• pp.1495-1507
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• 2022

The improvement of thermal-hydraulic analysis techniques is essential to ensure the safety and reliability of nuclear power plants. The one-dimensional two-fluid model has been adopted in state-of-the-art thermal-hydraulic system codes. Current constitutive equations used in the system codes reach a mature level. Some exceptions are the partition method of wall friction in the momentum equation of the two-fluid model and the interfacial drag force model for a horizontal two-phase flow. This study is focused on deriving the partition method of wall friction in the momentum equation of the two-fluid model and modeling the interfacial drag force model for a horizontal bubbly flow. The one-dimensional momentum equation in the two-fluid model is derived from the local momentum equation. The derived one-dimensional momentum equation demonstrates that total wall friction should be apportioned to gas and liquid phases based on the phasic volume fraction, which is the same as that used in the SPACE code. The constitutive equations for the interfacial drag force are also identified. Based on the assessments, the Rassame-Hibiki correlation, Hibiki-Ishii correlation, Ishii-Zuber correlation, and Rassame-Hibiki correlation are recommended for computing the distribution parameter, interfacial area concentration, drag coefficient, and relative velocity covariance of a horizontal bubbly flow, respectively.

• Journal of Positioning, Navigation, and Timing
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• v.11 no.3
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• pp.181-189
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• 2022

The public open signals from Global Navigation Satellite System (GNSS) including Global positioning system (GPS) are used widely by many peoples in the world except for the public regulated restriction signals which are encrypted. Nowadays there are growing concerns about GNSS signal spoofing which can deceive the GNSS receivers by abusing these open services. To counter these spoofing threats, many researches have been studied including array antenna techniques which can detect the direction of arrival by means of Multiple Signal Classification (MUSIC) algorithm. Originally the array antenna techniques were developed to countermeasure the jamming signal in electronic warfare by using the nulling or beamforming algorithm toward a certain direction. In this paper, we study the anti-spoofing techniques using array antenna to overcome the jamming and spoofing issues simultaneously. First, we will present the theoretical analysis results of spoofing signal response of Minimum Variance Distortionless Response (MVDR) algorithm in array antenna. Then the eigenvector algorithm of covariance matrix is suggested and verified to work with the existing anti-jamming method. The modeling and simulation are used to verify the effectiveness of the anti-spoofing algorithm. Also, the field test results show that the array antenna system with the proposed algorithms can perform the anti-spoofing function. This anti-spoofing method using array antenna is very effective in the view point of solving both the jamming and spoofing problems using the same array antenna hardware.

• Journal of the Korean Society of Food Culture
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• v.23 no.3
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• pp.301-307
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• 2008

The purpose of this study was to assess the causal relationships among belief, subjective norm, moral feeling, attitude, and the intention to consume organic beef. A total of 326 questionnaires were completed by adult in Jeonnam area. Structural equation modeling was used to measure the causal relationships among the constructs. The structural analysis results indicated an excellent model-data fit. The covariance effects of belief and subjective norm, and belief and moral feeling were statistically significant. The effects of belief and moral feeling on attitude and intention to consume were also statistically significant. As expected, attitude had significant effects on intention to consume. Moreover, attitude played a mediating roles in the relationship between belief and intention to consume. Finally, based on structural analysis, a model was proposed for the interrelations among belief, subjective norm and moral feeling towards organic food, attitude and intention to consume. It should be noted that the original organic food consumption model was modified, and should preferably be validated by future research. Other constructs, such as perceived behavior control and consumption, may be incorporated to form models that consist of new antecedent and consequence pairs.

• Communications for Statistical Applications and Methods
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• v.30 no.4
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• pp.369-388
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• 2023

In this paper, we develop the two-step procedure that detects and estimates the position of structural changes for multivariate nonstationary time series, either on mean parameters or second-order structures. We first investigate the presence of mean structural change by monitoring data through the aggregated cumulative sum (CUSUM) type statistic, a sequential procedure identifying the likely position of the change point on its trend. If no mean change point is detected, the proposed method proceeds to scan the second-order structural change by modeling the multivariate nonstationary time series with a multivariate locally stationary Wavelet process, allowing the time-localized auto-correlation and cross-dependence. Under this framework, the estimated dynamic spectral matrices derived from the local wavelet periodogram capture the time-evolving scale-specific auto- and cross-dependence features of data. We then monitor the change point from the lower-dimensional approximated space of the spectral matrices over time by applying the dynamic principal component analysis. Different from existing methods requiring prior information on the type of changes between mean and covariance structures as an input for the implementation, the proposed algorithm provides the output indicating the type of change and the estimated location of its occurrence. The performance of the proposed method is demonstrated in simulations and the analysis of two real finance datasets.

• Korean Journal of Health Education and Promotion
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• v.23 no.3
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• pp.99-119
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• 2006

Objectives: This study intends to understand the difference within group of social support level and the effect of social support to health behaviors and health status of the elderly by selecting the old of local society as target. Methods: Data were obtained from self-administered questionnaire of 8,688 persons, older than 65 years, living in a community. We measured the sociodemographic characteristics, social support(family support, other support, quality of support), physical health state(subjective health status, number of chronic disease), physical function state(activities of daily living; ADL, instrumental activities of daily living; IADL), cognition state(mini-mental state examination-Korean; MMSE-K) and depression state(short form of geriatric depression scale; SGDS), health behaviors(smoking, drinking, exercise, eating habit). Univariate, multinominal logistic regression and covariance structure analysis were employed to analyze factors affecting on the social support of the elderly. Results: When considering the degree of social support by the sociodemographic characteristics of the older adults, the family support, other support and quality of support is better when the old is male, young, high education and self-reported living status is good and it has significance statistically. When considering the relation between social support and health status, the family support, other support and quality of support is better when the old's subjective and objective physical health status is good. The family support, other support and quality of support is better when the old's subjective health status is better. The other support and quality of support is better when the old's ADL(activities of daily living) and IADL(instrumental activities of daily living) are good. The family support, other support and quality of support is better when the old's cognitive function and depression state is better. When considering the relation between social support and health behaviors, in case of smoking and drinking, the quality of support, family support and other support is better when the old smokes and drinks rather than the old does not. In case of exercise and eating habit, the family support, other support and quality of support is better when the old exercises and eats regularly rather than the old does not. It has significance statistically. From the result of performing covariance structure analysis by structural equation modeling(SEM) with two endogenous variable(health behaviors and health status) and one exogenous variable(social support), factor loading of health status is 0.74 and factor loading of health behaviors is 0.05. The social support explains health status of 55.4% and health behaviors of 2.9%. Conclusions: This study has the meaning that it finds the difference of social support generating from inside of the group for the old residing in city and country and specifies the effect that the difference of social support influences to health status and health behaviors. From now on, in the development of health improvement strategy of the olds, it is necessary to approach from inclusive aspect while considering psychosocial factor such as social support and social economical factor as well as health status.

• Water for future
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• v.27 no.1
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• pp.89-99
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• 1994

Flood forecasting in Korea has been based on the off-line parameter estimation method. But recent flood forecasting studies explore on-line recursive parameter estimation algorithms. In this study, a simultaneous adaptive estimation of system states and parameters for rainfall-runoff model is investigated for on-line real-time flood forecasting and parameter estimation. The proposed flood routing system is composed of Flood forecasting in Korea has been based on the off-line parameter estimation method. But recent flood forecasting studies explore on-line recursive parameter estimation algorithms. In this study, a simultaneous adaptive estimation of system states and parameters for rainfall-runoff model is investigated for on-line real-time flood forecasting and parameter estimation. The proposed flood routing system is composed of ø-index in the assessment of effective rainfall and the cascade of nonlinear reservoirs accounting for translation effect in flood routing. To combine the flood routing model with a parameter estimation model, system states and parameters are treated with the extended state-space formulation. Generalized least squares and maximum a posterior estimation algorithms are comparatively examined as estimation techniques for the state-space model. The sensitivity analysis is to investigate the identifiability of the parameters. The index of sensitivity used in this study is the covariance matrix of the estimated parameters.-index in the assessment of effective rainfall and the cascade of nonlinear reservoirs accounting for translation effect in flood routing. To combine the flood routing model with a parameter estimation model, system states and parameters are treated with the extended state-space formulation. Generalized least squares and maximum a posterior estimation algorithms are comparatively examined as estimation techniques for the state-space model. The sensitivity analysis is to investigate the identifiability of the parameters. The index of sensitivity used in this study is the covariance matrix of the estimated parameters.

• Korean Journal of Agricultural and Forest Meteorology
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• v.5 no.2
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• pp.61-69
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• 2003

Surface energy and $CO_2$ fluxes have been measured over a farmland in Haenam, Korea since July 2002. Eddy covariance technique, which is the only direct flux measurement method, was employed to quantitatively understand the interaction between the farmland ecosystem and the atmospheric boundary layer. Maintenance of eddy covariance system was the main concern during the early stage of measurement to minimize gaps and uncertainties in the dataset. Half-hourly averaged $CO_2$ concentration showed distinct diurnal and seasonal variations, which were closely related to changes in net ecosystem exchange (NEE) of $CO_2$. Daytime maximum $CO_2$ uptake was about -1.0 mg $CO_2$ m$^{-2}$ s$^{-1}$ in August whereas nighttime $CO_2$ release was up to 0.3 mg $CO_2$ m$^{-2}$ s$^{-1}$ during the summer. Both daytime $CO_2$ uptake and nighttime release decreased gradually with season. During the winter season, NEE was from near zero to 0.05 mg $CO_2$ m$^{-2}$ s$^{-1}$ . FK site was a moderate sink of atmospheric $CO_2$ until September with daily NEE of 22 g $CO_2$ m$^{-2}$ d$^{-1}$ . In October, it became a weak source of $CO_2$ with an emission rate of 2 g $CO_2$ m$^{-2}$ d$^{-1}$ . Long-term flux measurements will continue at FK site to further investigate inter-annual variability in NEE. to better understand these exchange mechanism and in-depth analysis, process-level field experiments and intensive short-term intercomparisons are also expected to be followed.