• The Korean Journal of Applied Statistics
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• v.27 no.1
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• pp.89-102
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• 2014

In this study, we analyze the effect on the smoking status in the Seoul Metropolitan area using a multilevel logistic model with Community Health Survey data from the Korea Centers for Disease Control and Prevention. Intraclass correlation coefficient (ICC), profiling analysis and two types of predicted value were used to determine the appropriate multilevel analysis level. Sensitivity, specificity, percentage of correctly classified observations (PCC) and ROC curve evaluated model performance. We showed the applicability for multilevel analysis allowed for the possibility that different factors contribute to within group and between group variability using survey data.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.710-715
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• 2004

The design problem of manufacturing system is addressed, adopting the closed queueing network model with multiple loops and re-entrant flows. The entire design problem is divided into two hierarchical sub-problems of (1) determining the station configuration and (2) optimizing the lot constitution; then they are tackled by neighbor search algorithm (NSA) and greedy mean value analysis (GMVA), respectively. Unlike the conventional MVA concerning multi-class closed queueing networks, the GMVA doesn't stick to a fixed lot proportion; rather it tries to find the optimal balance. The NSA, on the other hand, improves the object function value by altering the station configuration successively with its superior neighbor. The moderate time complexity, presented in big-${o}$ notation, enables us to apply the method even to the large-size practical cases, and the CPU time of an enlarged problem can be approximated by the same equation. The validity of our analytic approach is backed up by simulation studies with a widespread simulation package.

• Korean Business Review
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• v.20 no.1
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• pp.19-32
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• 2007

As business environments rapidly changing and becoming more competitive, manager begin to realize the needs of the network organization structure reflecting the newly emerging internet environments. This paper, therefore, attempt to provide managers with a framework that can be used to design an effective network structure. The framework described here shows three important characteristics of network organizations: First, staffs need to be knowledge workers, rather than rule follower. Second, managers need to emphasize the empowerment, rather than exercising hierarchical power and control. In order for managers to support the design of network organizations they need to implement information systems that can integrate staffs, tasks, and information technologies.

• Journal of Korean Academy of Nursing Administration
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• v.7 no.1
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• pp.41-51
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• 2001

Today's health care environment is rapidly changing and nurse administrators' leadership styles need to identify in nursing organization to achieve organizational objectives. By Bass(1985), transformational leadership stimulates the subordinates to be creative and achieve organizational objectives and is related to job satisfaction, job involvement, productivity, and organizational commitment. Transformational leadership process consists of charisma, intellectual stimulation, individual consideration. The purpose of this study is to identify the effect of transformational leadership and personal characteristics on nurses' organizational commitment. The subjects for this study consisted of 594 nurse from 8 University Hospitals and General Hospitals. The data were collected by personal characteristics scale, transformational leadership scale, and organizational commitment scale. The factor analysis, Cronbach's alpha analysis, Pearson correlation analysis, multiple regression analysis and hierarchical multiple regression analysis were used for the statistical method. The results of this study were found that (1) charisma dimension of transformational leadership has positive influence on nurses' organizational commitment; but another two dimensions(intellectual stimulation and individualized consideration) did not showed significant effect on organizational commitment (2) nurses' personal characteristic(internal locus of control) moderated the effect of transformational leadership on organizational commitment.

• The Journal of Korean Academic Society of Nursing Education
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• v.23 no.2
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• pp.205-213
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• 2017

Purpose: This study observes the degrees of perfectionism (both self-oriented and socially-prescribed perfectionism), academic resilience, and satisfaction with major in nursing students and identifies the influence of perfectionism and academic resilience on satisfaction with major. Methods: Data from 115 second or third-year students in a nursing were collected for two months at different three universities. The data were analyzed with descriptive statistics, independent t-test, one-way ANOVA, Pearson correlation coefficient, and hierarchical multiple regression. Results: Satisfaction with major was higher for second year students compared to third year students. And the satisfaction was higher for those with a higher Grade point average (${\geq}_-3.5$) compared to those with a lower. Self-oriented perfectionism had a higher score than socially-prescribed perfectionism and academic resilience based on self-control was rated the highest score of the subcategories. The degree of satisfaction was positively correlated with Self-oriented perfectionism and academic resilience. The final regression model showed that grade and academic resilience accounted for 34.2% of the variance in predicting the level of satisfaction with major. Conclusion: The results suggest that it is crucial to find a strategy that could enhance academic resilience, especially designed for upper-year university students, to improve the level of satisfaction with major.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.3
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• pp.941-955
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• 2015

In dual-channel networks (DCNs), all frequency hopping (FH) sequences used for data channels are chosen from the original FH sequence used for the control channel by shifting different initial phases. As the number of data channels increases, the hitting frequency point problem becomes considerably serious because DCNs is non-orthogonal synchronization network and FH sequences are non-orthogonal. The increasing severity of the hitting frequency point problem consequently reduces the resource utilization efficiency. To solve this problem, we propose a novel hitting frequency point collision avoidance method, which consists of a sequence-selection strategy called sliding correlation (SC) and a collision avoidance strategy called keeping silent on hitting frequency point (KSHF). SC is used to find the optimal phase-shifted FH sequence with the minimum number of hitting frequency points for a new data channel. The hitting frequency points and their locations in this optimal sequence are also derived for KSHF according to SC strategy. In KSHF, the transceivers transmit or receive symbol information not on the hitting frequency point, but on the next frequency point during the next FH period. Analytical and simulation results demonstrate that unlike the traditional method, the proposed method can effectively reduce the number of hitting frequency points and improve the efficiency of the code resource utilization.

• Journal of Korean Public Health Nursing
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• v.15 no.2
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• pp.249-261
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• 2001

Today's health care environment is rapidly changing and nurse administrators' leadership styles need to identify in nursing organization to achieve organizational objectives. By Bass(1985), transformational leadership stimulates the subordinates to be creative and achieve organizational objectives and is related to job satisfaction, job involvement, productivity, and organizational commitment. Transformational leadership process consists of charisma, intellectual stimulation, individual consideration. The purpose of this study was to identify the effect of transformational leadership and personal characteries on nurses' job involvement. The subjects for this study consisted of 594 nurses from 8 University Hospitals and General Hospitals. The data were collected by personal characteristics scale, transformational leadership scale, and job involvement scale. The factor analysis, Cronbach's alpha analysis, Pearson correlation analysis, multiple regression analysis and hierarchical multiple regression analysis were used for the statistical method. The results of this study were found that (1) charisma dimension of transformational leadership has positive influence on nurses' job involvement ; but another two dimensions (intellectual stimulation and individualized consideration) did not showed significant effect on job involvement (2) nurses' personal characteristic (internal locus of control) moderated the effect of transformational leadership on job involvement.

• Human Ecology Research
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• v.52 no.4
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• pp.415-427
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• 2014

The purpose of this study was to determine the effect of expenditure on private education and stress caused by private education on the parental efficacy of mothers of junior and senior high school students. The subjects were 300 mothers of students who were enrolled in the junior and senior high school in Seoul and its suburbs. The results were as follows: First, the level of stress from private education was found to be higher than the degree of parental efficacy. Second, a hierarchical regression analysis was performed by using expenditure on private education and stress caused by private education as independent variables and the socio-demographic characteristics of mothers as control variables in order to identify their effect on the parental efficacy of mothers of junior and senior high school students. The results show that stress from private education and monthly income were significantly related to parental efficacy. That is, the lower the level of stress from private education and the higher the monthly income, the higher was the degree of parental efficacy. These findings suggest that expenditure on private education seems to be determined by the household income level; thus, income may affect psychological stress and parental efficacy of mothers with respect to the process of providing private education.

• Journal of Korea Society of Digital Industry and Information Management
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• v.11 no.3
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• pp.69-77
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• 2015

MANET is composed of only the mobile nodes have a limited transmission range. The dynamic topology by the frequent movement of nodes makes routing difficult and is also cause exposed to security vulnerabilities. In this paper, we propose the security routing technique consisted of mechanism of two steps in order to respond effectively to attack by the modification of the routing information and transmit secure data. The hierarchical structure is used and the authentication node that issues the key of the nodes within each cluster is elected in this proposed method. The authentication node manages key issues and issued information for encrypting the routing information from the source node. The reliability value for each node is managed to routing trust table in order to secure data transmission. In the first step, the route discovery is performed using this after the routing information is encrypted using the key issued by the authentication node. In the second step, the average reliability value of the node in the found path is calculated. And the safety of the data transmission is improved after the average reliability value selects the highest path. The improved performance of the proposed method in this paper was confirmed through comparative experiments with CBSR and SEER. It was confirmed a better performance in the transmission delay, the amount of the control packet, and the packet transmission success ratio.

• Journal of Korean Institute of Industrial Engineers
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• v.21 no.1
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• pp.85-101
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• 1995

Automated Guided Vehicles(AGVs) are widely used in computer integrated manufacturing(CIM) systems for material handling purposes. Although automated guided vehicles provide higher levels of flexibility and computer integrability, the installations are limited in number and one of the critical reasons lies in the complexity involved in the operation. The main objective of this research is to alleviate this problem by proposing efficient integrated operational control methods for AGV-based CIM systems. Particularly, this research is concerned with the mixed problem of dispatching automated guided vehicles and scheduling machines operation. The proposed dynamic heuristic algorithm uses various priority schemes and relevant information concerning the load of the system, the status of queues, and the position of AGVs in the scheduling process. The scheduling decision process is hierarchical in the sense that different decision criteria are applied sequentially to identify the most appropriate part to be served. This algorithm consists of two sections, the section of part selection by AGVs for the next service whenever an AGV completes the current assignment, and the section of part selection by machines for next service whenever a machine completes the current operation. The proposed algorithm has been compared with other scheduling schemes using the performance measure of mean flow-time and mean tardiness. Simulation results indicate that the proposed algorithm can reduce the mean flow-time and mean tardiness significantly.