• The Transactions of the Korean Institute of Electrical Engineers C
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• v.49 no.4
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• pp.249-257
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• 2000

In this paper, we propose the use of stochastic finite element method, that is popularly employed in mechanical structure analysis, for more practical designing purpose of RF device. The proposed method is formulated based on the vector finite element method cooperated by pertubation analysis. The method utilizes sensitivity analysis algorithm with covariance matrix of the random variables that represent for uncertain physical quantities such as length or various electrical constants to compute the probabilities of the measure of performance of the structure. For this computation one need to know the variance and covariance of the random variables that might be determined by practical experiences. The presenting algorithm has been verified by analyzing several device with different be determined by practical experiences. The presenting algorithm has been verified by analysis several device with different measure of performanes. For the convenience of formulation, two dimensional analysis has been performed to apply it into waveguide with dielectric slab. In the problem the dielectric constant of the dielectric slab is considered as random variable. Another example is matched waveguide and cavity problem. In the problem, the dimension of them are assumed to be as random variables and the expectations and variances of quality factor have been computed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.04a
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• pp.974-979
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• 2008

A design process for the structure-borne noise in a passenger vehicle is presented. The proposed process is improved from the previous one. The major difference between the current and last ones is that most of the countermeasures should be developed before fixing a tool for structural parts. This is requested for QCDP(Quality, Cost, Delivery and Productivity) by the design engineers. The proposed one consists of 4 steps: Problem definition, Cause analysis, Development of counter-measure and Validation. Based on the general rule: divide and conquer, the complex problem can be simplified into a few critical sub-systems through the first step: Problem definition. Secondly, the critical causes can be identified for the critical sub-systems through the second step: Cause analysis. Thirdly, effective countermeasures are investigated and produced through the third step: Countermeasure development. The proposed countermeasures are finally validated in the forth step: Validation.

• Journal of the Korean School Mathematics Society
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• v.14 no.2
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• pp.143-161
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• 2011

Mathematics PBL, which has recently attracted much attention, is a teaching and learning method to increase mathematical ability and help learning mathematical concepts and principles through problem solving using mathematical knowledge the students have. In spite of the attention, however, the implementations are yet significant. In this study, we worked to find the needs of mathematics teachers for mathematics PBL implementation. The methods of this study are taxonomic analysis and componential analysis by using cards depth interviewing. As a result, mathematics teachers' needs are to consider how to develop the mathematics PBL problems and how to make progress.

• Proceedings of the KIEE Conference
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• 1999.11b
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• pp.21-23
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• 1999

In this paper, the analysis of the electric field in the chamber of high voltage $SF_6$ GCB(Gas Circuit Breaker) is presented by using C-1 FEM. For this purpose, pre-processing program and post-processing program were developed for axisymmetirc 3 dimensional analysis and the electric field in cylindric chamber was analyzed. Important problem is that electric analysis must be considered coronal due to break-down of $SF_6$ when it is cutted off. To solve this problem, a procedure is needed to verify that the solution of Poisson's equation for scalar potential satisfy charge continuos condition because of using first order element os not satisfy the electric continuous condition, C-1 FEM is introduce to obtain electirc potential and electric field at the same time. Analysis of the distribution of electric field on model was done. It is confirmed that the developed program in this paper applicable to design and to analyze of characteristics in total program as electric characteristics analysis routine.

• Journal of Power System Engineering
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• v.9 no.4
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• pp.220-224
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• 2005

The thermal elasto-plastic analysis for the prediction of welding distortion of a 3 dimensional large-scaled ship structure is a very time-consuming work since the analysis is a nonlinear problem, and a lot of finite elements are needed to simulate the large ship hull block. Generally, 3-D finite elements have been used in the 3-D welding distortion problem to assess precisely the temperature gradient through the thickness direction of the welding plate. As a result of the adoption of 3-D element, degrees of freedom are rapidly increased in the problem to be solved. In this study, to improve the time efficiency of welding thermal elasto-plastic analysis, a layered shell element was proposed to simulate 3-D temperature gradient, and the results were compared with the experiment. The experiments were carried out for the type of bead-on-plate welding, and we found the measured data have a good agreement with the FEA results.

• Journal of Korean Clinical Nursing Research
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• v.18 no.3
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• pp.402-412
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• 2012

Purpose: The purpose of this study was to explore influencing factors of dysfunctional beliefs and emotion regulation strategy for nurses' problem solving ability. Methods: This study was a cross-sectional design with a sample of 745 nurses from 1 university hospital located in Gyeonggido. The scales were Dysfunctional Beliefs Test (70 items), Emotion Regulation Strategy Questionnaire (25 items) and Social Problem Solving Inventory (52 items). The data were analyzed using SPSS 17.0 employing ANOVA, pearson correlation coefficients and multiple regression analysis. Results: The mean score for problem solving ability was 11.26 points. Influencing factors for nurses' problem solving ability were identified as 'active regulation style' in emotion regulation strategy and 'negative concept of social self' in dysfunctional beliefs. Conclusion: It is plausible to assume that dysfunctional beliefs which are vulnerability factors in cognitive variables and emotion regulation strategy affect nurses' problem solving ability.

• Journal of Computational Design and Engineering
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• v.3 no.4
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• pp.295-311
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• 2016

This paper addresses to the flowshop scheduling problem with blocking constraints. The objective is to minimize the makespan criterion. We propose a hybrid combinatorial particle swarm optimization algorithm (HCPSO) as a resolution technique for solving this problem. At the initialization, different priority rules are exploited. Experimental study and statistical analysis were performed to select the most adapted one for this problem. Then, the swarm behavior is tested for solving a combinatorial optimization problem such as a sequencing problem under constraints. Finally, an iterated local search algorithm based on probabilistic perturbation is sequentially introduced to the particle swarm optimization algorithm for improving the quality of solution. The computational results show that our approach is able to improve several best known solutions of the literature. In fact, 76 solutions among 120 were improved. Moreover, HCPSO outperforms the compared methods in terms of quality of solutions in short time requirements. Also, the performance of the proposed approach is evaluated according to a real-world industrial problem.

• Journal of Engineering Education Research
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• v.19 no.6
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• pp.3-9
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• 2016

Amonng many creative problem-solving methodologies, the TRIZ with practicality and applicability has been utilized a lot in practice and education. This research introduced the TRIZ course for engineering problem-solving training to engineering college students. Then, a survey about students' ability to solve engineering problems after the TRIZ course were analyzed statistically. Finally, problem-solving cases of industry in each team project were examined. It is proved that an understanding of the TRIZ should be confirmed on that can be applied and utilized and can be linked to well performing team projects. Therefore, it is determined that more active efforts are required for the development of TRIZ learing methods to improve the education system to help students improve comprehension for students in creative problem-solving skills.

• Journal of Korean Institute of Industrial Engineers
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• v.35 no.1
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• pp.1-14
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• 2009

The efficiency of transportation requests fulfillment can be increased through extending the problem of vehicle routing and scheduling by the possibility of subcontracting a part of the requests to external carriers. This problem extension transforms the usual vehicle routing and scheduling problems to the more general integrated operational transportation problems. In this contribution, we analyze the motivation, the chances, the realization, and the challenges of the integrated operational planning and report on experiments for extending the plain Vehicle Routing Problem to a corresponding problem combining vehicle routing and request forwarding by means of different sub-contraction types. The extended problem is formalized as a mixed integer linear programming model and solved by a commercial mathematical programming solver. The computational results show tremendous costs savings even for small problem instances by allowing subcontracting. Additionally, the performed experiments for the operational transportation planning are used for an analysis of the decision on the optimal fleet size for own vehicles and regularly hired vehicles.

• Journal of Korean Elementary Science Education
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• v.26 no.3
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• pp.286-294
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• 2007

This study investigated the relationship between elementary school students' creative problem solving skills in terms of science and cognitive strategies. Creative problem solving in science was measured by 4 variables; appropriateness, scientific ability, concreteness, and originality. Cognitive strategies were measured by 6 variables; surface(rehearsal), deep(elaboration and organization), and metacognitive strategies(planning, monitoring, and regulating). The KEDI Creative Problems Solving Test in Science(Cho et al., 1997) and the Motivated Strategies for Learning Questionnaire(Pintrich & DeGroot, 1990) were administered to 72 subjects. Data were analyzed by means of Pearson's correlation and multiple regression analysis. Our findings indicated a positive correlation between creative problem solving in science and cognitive strategies. The surface cognitive strategy (rehearsal) positively predicted the total score, the scientific ability's score, the concrete score, and the original score of creative problem solving in science. The deep cognitive strategy(organization) positively predicted the appropriate score and the metacognitive strategy(planning) positively predicted the original score of scientific creative problem solving skills.