• Journal of Advanced Marine Engineering and Technology
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• 제38권10호
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• pp.1303-1309
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• 2014

In this paper, we present an iterative learning control (ILC) framework for tracking problems with predefined data points that are desired points at certain time instants. To design ILC systems for such problems, a new ILC scheme is proposed to produce output curves that pass close to the desired points. Unlike traditional ILC approaches, an algorithm will be developed in which the control signals are generated by solving an optimal ILC problem with respect to the desired sampling points. In another word, it is a direct approach for the multiple points tracking ILC control problem where we do not need to divide the tracking problem into two steps separately as trajectory planning and ILC controller.The strength of the proposed formulation is the methodology to obtain a control signal through learning law only considering the given data points and dynamic system, instead of following the direction of tracking a prior identified trajectory. The key advantage of the proposed approach is to significantly reduce the computational cost. Finally, simulation results will be introduced to confirm the effectiveness of proposed scheme.

• 대한기계학회논문집
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• 제18권2호
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• pp.313-322
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• 1994

Structural optimization has been developed by two methods. One is the direct method which applies the Nonlinear Programming (NLP) algorithm directly to the structural optimization problem. This method is known to be very excellent mathematically. However, it is very expensive for large-scale problems due to the one-dimensional line search. The other method is the approximation method which utilizes the engineering senses very well. The original problem is approximated to a simple problem and an NLP algorithm is adopted for solving the approximated problems. Practical solutions are obtained with low cost by this method. The two methods are compared through standard structural optimization problems. The Finite element method with truss and beam elements is used for the structural and sensitivity analyses. The results are analyzed based on the convergence performances, the number is function calculations, the quality of the cost functions, and etc. The applications of both methods are also discussed.

• 대한조선학회지
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• 제24권4호
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• pp.19-36
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• 1987

In this research the coupling problem between the elastic structure and the fluid, specially the hydroelastic harmonic vibration problem, is studied. In order to couple the domains, i.e., the structural domain and the fluid domain, the boundary integral method(direct boundary integral formulation) is used in the fluid domain in combination with the finite element method for the structure. The boundary integral method has been widely developed to apply it to the hydroelastic vibration problem. The hybrid boundary integral method using eigenfunctions on the radiation boundaries and the boundary integral method using the series form image-functions to replace the even bottom and free surface boundaries in case of high frequencies have been developed and tested. According to the boundary conditions and the frequency ranges the different boundary integral methods with the different idealizations of the fluid boundaries have been studied. Using the same interpolation functions for the pressure distribution and the displacement the two domains have been coupled and using Hamilton principle the solution of the hydroelastic have been obtained through the direct minimizing process. It has become evident that the finite-boundary element method combining with the eigenfunction or the image-function method give good results in comparison with the experimental ones and the other numerical results by the finite element method.

• 한국농촌건축학회논문집
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• 제18권4호
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• pp.17-24
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• 2016

Since the users have direct access to search and browse freely, the open access system has been employed to all the usual modern libraries. However, library space shortage problem created by the continuously increasing printed materials caused the degradation of usability and quality of the library space. Open Access system is superior in user convenience but is inferior in space efficiency. Keeping the open access system is considered as one of the reasons of the space shortage problem. Even though the closed access system does not provide free access or easy browsing for the uses, it's space efficiency is much higher than the open access system. The closed access system should be employed as a plan to relieve space shortage problem. Since the closed access system does not allow the public direct access to books, it is very economical. It also provides much better space efficiency with higher book shelving density. In this article, closed access library system models and their characteristics are examined as the reduction plans for the library space shortage problems.

• 한국보건간호학회지
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• 제30권3호
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• pp.381-394
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• 2016

Purpose: In this study, the fitness of a path model on suicidal ideation in university students was examined including the relationship of the following stress perception, problem focused coping style, dysfunctional impulsivity, somatization, anger, and depression. Methods: The subjects consisted of 645 university students. Data was collected using questionnaires and analyses was performed using SPSS/WIN 12.0 and LISREL 8.30. Results: According to the modified model, depression was found to have the most significant direct effect on suicidal ideation. Stress perception and problem focused coping style were also found to have a significant direct effect on suicidal ideation. On the other hand the anger, somatization, and dysfunctional impulsivity were found to have a significant indirect effect mediated by depression on suicidal ideation. Conclusion: These results suggest that university students' suicidal ideation can be decreased by managing stress perception, dysfunctional impulsivity, depression, anger, and somatization and increasing problem focused coping style. Based on the outcomes of this study, it is necessary to develop stress management methods and positive coping styles.

• 아동학회지
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• 제36권3호
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• pp.19-34
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• 2015

The purpose of this study was to explore the influence of marital satisfaction and depression of adoptive mother on the problem behaviors of adopted children and the mediating effects of parenting competency between them. Contextual variables such as family background and adoption-related characteristics were also included as control variables. The results of multiple regression analysis showed marital satisfaction had significant influence on the problem behavior of adopted child through flexibility of parenting competency, while depression was not significantly related to parenting competency of adoptive mother. Yet, maternal depression had direct influence on the problem behavior of adopted child. Based on the limitations of the study, suggestions for further study were made.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제12권3호
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• pp.191-199
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• 2008

This paper proposes a new method for the inverse problem of the three-dimensional reconstruction of the electrical activity of the brain from electroencephalography (EEG). Compared to conventional direct methods using additional parameters, the proposed approach solves the EEG inverse problem iteratively without any parameter. We describe the Lagrangian corresponding to the minimization problem and suggest the numerical inverse algorithm. The restriction of influence space and the lead field matrix reduce the computational cost in this approach. The reconstructed divergence of primary current converges to a reasonable distribution for three dimensional sphere head model.

• Management Science and Financial Engineering
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• 제13권2호
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• pp.1-27
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• 2007

This paper presents a fuzzy-goal programming(FGP) approach for Bi-Level Linear Multiple Objective Decision Making(BLL-MODM) problem in a large hierarchical decision making and planning organization. The proposed approach combines the attractive features of both fuzzy set theory and goal programming(GP) for MODM problem. The GP problem has been developed by fixing the weights and aspiration levels for generating pareto-optimal(satisfactory) solution at each level for BLL-MODM problem. The higher level decision maker(HLDM) provides the preferred values of decision vector under his control and bounds of his objective function to direct the lower level decision maker(LLDM) to search for his solution in the right direction. Illustrative numerical example is provided to demonstrate the proposed approach.

• 지역사회간호학회지
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• 제29권3호
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• pp.300-309
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• 2018

Purpose: This study aims to investigate the effects of intervention using the therapeutic robot, PARO, on the cognition, emotion, problem behavior, and social interaction of elderly people with dementia. Methods: A nonequivalent control group pretest-posttest design was used. A total of 33 elderly people with dementia living in a nursing home facility participated in the study, with 17 in the experimental group and 16 in the control group. The intervention program with PARO was administered twice a week for 6 weeks, for a total of 12 sessions. Data were collected before and after intervention, using a questionnaire, direct observation, and video recording. Results: There were statistically significant differences in positive emotions and problem behaviors between the groups. The experimental group demonstrated a significant improvement in social interaction. Conclusion: PARO intervention can be utilized as an effective nursing intervention to increase positive emotions and social interaction, as well as decrease problem behaviors, in elderly people with dementia living in nursing home facilities.

• 한국컴퓨터정보학회논문지
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• 제21권1호
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• pp.131-138
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• 2016

In this paper, we propose a simple linear bottleneck assignment problems (LBAP) algorithm to find the optimal solution. Generally, the LBAP has been solved by threshold or augmenting path algorithm. The primary characteristic of proposed algorithm is derived the optimal solution of LBAP from linear sum assignment problem (LSAP). Firstly, we obtains the solution for LSAP from the selected minimum cost of rows and moves the duplicated costs in row to unselected row with minimum increasing cost in direct and indirect paths. Then, we obtain the optimal solution of LBAP according to the maximum cost of LSAP can be move to less cost. For the 29 balanced and 7 unbalanced problem, this algorithm finds optimal solution as simple.