• Proceedings of the IEEK Conference
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• 2009.05a
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• pp.76-78
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• 2009

This paper considers the problem of global adaptive regulation for a class of nonlinear systems which have multiple unknown virtual control coefficient. By using a new parameter estimator and backstepping technique, we design a smooth state feedback control law, parameter update laws that estimate the unknown virtual control coefficients, and a continuously differentiable Lyapunov function which is positive definite and proper.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1994.04a
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• pp.427-431
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• 1994

The objective of this paper is to provide an inventory control policy for the system that carries a single item with a multiple demand classes, when the demand is Poisson distributed random variable. The inventory control process includes the process of determining the reorder point, and the process of inventory control during the lead time. The goal of the optimization process is to achieve the service level of each demand class as well as the system-wide total service level at a preset desired service level while sustaining a minimum average inventory.

• Journal of applied mathematics & informatics
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• v.30 no.1_2
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• pp.305-320
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• 2012

In this paper, we study a class of integral boundary value problems for fractional differential equations. By using some fixed point theorems, the results of existence of at least three positive solutions for the boundary value problems are obtained.

• Journal of applied mathematics & informatics
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• v.30 no.5_6
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• pp.741-748
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• 2012

In this work, we prove the instability of solutions for a class of nonlinear functional differential equations of the eighth order with n-deviating arguments. We employ the functional Lyapunov approach and the Krasovskii criteria to prove the main results. The obtained results extend some existing results in the literature.

• Journal of KIISE:Computing Practices and Letters
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• v.15 no.5
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• pp.370-374
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• 2009

In this paper we propose an adjustment algorithm for bandwidth grant interval of UGS class flows the overload status of certain frames occurs due to the pre-defined grant interval mechanism of UGS class. In IEEE 802.16/WiBro systems, UGS class is the highest priority to guaranteed QoS Parameters. However, existing grant interval mechanisms of UGS class do not consider the condition that the grant interval of multiple UGS class flows overlaps with certain frames, and thus it causes the overload status in the system. Therefore, the system cannot be guaranteed QoS for UGS class flows. In this paper, we show the occurrence of the problem through simulation studies and propose an adjustment algorithm to solve the problem. Our simulation results show that there is performance improvement in the proposed algorithm. We expect that the real system in which the proposed scheme is applied can provide more stable QoS services by reducing the delay problem that occurs due to the occurrence of the existing grant interval problem of UGS class.

• Journal of Digital Convergence
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• v.14 no.9
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• pp.579-588
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• 2016

This study is to identify the relationship between cultural physical education class of enjoyment factor, class satisfaction, and exercise continuation behavior. For this purpose, 275 out of 300 copies of survey aimed at students in four universities located in Gyeong-gi province were used. PAWS 18.0 program was used for analysis to present descriptive statistics. Principal component analysis and rotation of Max Berry were used among exploratory factor analysis to check factor extraction and internal consistency. Cronbach's alpha was used for checking reliability. Multiple regression analysis was used to clarify the relationship between enjoyment factor, class satisfaction, and exercise continuation behavior of cultural physical education. These are the following conclusions. First, instructional behavior, grade in physical education, environment, and exercise ability among the enjoyment factors in cultural physical education class have a significant effect on persistence of exercise. Second, instructional behavior and grade in physical education are the factors of class satisfaction and the have a significant effect on persistence of exercise.

• Korean Journal of Social Welfare Studies
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• v.44 no.3
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• pp.85-112
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• 2013

This study aims to understand the developmental trajectories of life satisfaction among retirees and to examine what factors differentiate different trajectory classes. This study used three waves of longitudinal data from Korean Retirement and Income Study and data collected every two years(2005, 2007, and 2009). Subjects were respondents aged 50-69 who identified to be retired between wave 1 and wave 2. Finally, this study used 243 respondents for final data analysis. Life satisfaction was measured by seven items. The latent class growth model and multiple logistic regression model were used for data analysis. This study identified three distinct trajectory classes: high stable class(47.7%), high at the early stage but decreased class(42.8%), and low at the early stage and then decreased class(9.5%). This study founded that approximately 50% of the retirees experienced the decline of life satisfaction after retirement and about 10% of the sample was the most vulnerable group. This study analyzed what factors make different among the distinct trajectory groups. As a results, retirees who experienced the improvement in health change were more likely to be in 'high stable class' compared to 'hight at the early stage but decreased class'. In addition, retirees who were less educated, maintained the same health status rather than the improvement, worked as a temporary or a day laborer, and had less household income were more likely to belong to 'low at the early stage and then decreased class' relative to 'high stable class'. This study suggests that there are distinct three trajectories on life satisfaction among the retirees and finds out factors differentiating between trajectory groups. Based on these findings, the study discusses the implications for social work practice and further study.

• The KIPS Transactions:PartD
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• v.11D no.1
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• pp.143-152
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• 2004

Recently, software programming method based on EJB for object oriented software design and implement has been used frequently. Usually, case that use permanent data that use Database in EJB base application is most. Part connected with Database-Access that take charge in Entity Bean class of server side creation program. In this paper using J2EE relationship DAO pattern class each separate. This is no much difference with existent pattern method, but in same pattern common classes are designed so that composition may be possible. And as well as use Entity Bean class that created each DBMS classes are different, is doing Rata Source so that connection work is available without alteration or creation of additional program in several DBMS environments.

• The Korean Journal of Applied Statistics
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• v.26 no.4
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• pp.661-674
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• 2013

We investigate the class registration behavior of college students with data collected from the spring semester of 2012. The network originally consists of a 2-mode network between a student and class subjects. We first transform the 2-mode network into 1-mode network of students. We also subdivide it into a smaller network such as components and communities to understand the detailed behavior of students in class registration. Finally, the relationship between GPA and the centrality measures, gender, and grade of students is analyzed using a multiple regression analysis.

• Journal of the Korean Home Economics Association
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• v.28 no.4
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• pp.103-117
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• 1990

The purpose of this study was to investigate the difference of mid-life family stress and family coping strategies according to conjugal sex and social class. This study was also intended to examine the relations between mid-life family stress and family coping strategies. The subjects of this study were 150 married couples(300 persons) who were 40 to 59 years old in Seoul. McCubbin, Wilson & Patterson (1979)'s "Family Inventory of Life Events and Changes" and McCubbin, Larsen & Olson (1982)'s "Family Coping Strategies" were used to gather data for the study. For the statistical analysis of data, factor analysis, T-test, Duncan's multiple Range Test, Pearson's r and cronbach's α for reliability were performed. The major results of this study were summarized as follows; 1. There were significant differences according to conjugal sex and social class in family stress; Wives reported more family stress than husbands. And the lower social class of the family, the more family stress were found. 2. There were some significant differences according to conjugal sex and social class in family coping strategies; Wives reported more family coping strategies than husbands in "freind and neighbor's support", "religious support". And the lower social class of the family, the more "passive attitudes" were found. 3. There were some significant correlations between family stress and family coping strategies; The higher extent of the total family stress, the lesser positive attitudes were found.