• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.181-181
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• 2000

We identified the performance problems of scheduling algorithms such as FCFS, and demonstrated the superiority of WFQ in terms of realtime performance measures. For this purpose, we presented the service scenario and performed the analysis for the delay bound and fairness which are required to support the realtime applications in the Internet.

• Communications of Mathematical Education
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• v.2
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• pp.181-191
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• 1997

The purpose of this study is to provide the primary sources to improve the problem solving performance by analyzing the errors and the strategies selection of the high school students when solving given algebraic problems. To attain the purpose of this study, the questions for investigation in this study are : 1. What are the differences / similarities in the patterns of errors committed by successful and unsuccessful problem-solvers when solving particular algebraic problems ? 2. What are the error types chosen by unsuccessful problem-solvers when solving particular algebraic problems? 3. Do students utilize checking, either locally or globally, when solving particular algebraic problems? Twenty students were drawn out of 10th grade students in J girls' high school in Yengi -gun, Chung-Nam, for this study. The problem-solving test was used as a test instrument. From the data, the verbal protocols and the written protocols were analyzed by the patterns. The conclusions drawn from the results obtained in the present study are as follows: First, in solving particular algebraic problems, when the problems were solved with one strategy, most students didn't give any consideration to other strategies. So mathematics teachers should teach them to use the various strategies, and should develop the problems to be used the various strategies. Second, in solving particular algebraic problems, errors on notions or transformations of equations were found. Thus, the basic knowledges related to equation should be taught. In addition, most unsuccessful students seleted the strategies inadequately to solve the problems because of misunderstanding the problems. So, to improve the problem solving performance the processes of 'understanding problem' should be emphasized to students. Third, although the unsuccesful students used the 'checking' processes when solving the problems, most of them did not find the errors because of misconceptions related to the problems, carelessness, and unskillfulness of checking. Thus, students must be taught more carefully and encouraged to use the checking.

• Earthquakes and Structures
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• v.15 no.2
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• pp.155-164
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• 2018

Design of structures subjected to blast loads are usually carried out through nonlinear inelastic dynamic analysis followed by imposing acceptance criteria specified in design codes. In addition to comprehensive aspects of inelastic dynamic analyses, particularly in analysis and design of structures subjected to transient loads, they inherently suffer from convergence and computational cost problems. In this research, a strategy is proposed for design of steel moment resisting frames under far range blast loads. This strategy is inspired from performance based seismic design concepts, which is here developed to blast design. For this purpose, an algorithm is presented to calculate the capacity modification factors of frame members in order to simplify design of these structures subjected to blast loading. The present method provides a simplified design procedure in which the linear dynamic analysis is preformed, instead of the time-consuming nonlinear dynamic analysis. Nonlinear and linear analyses are accomplished in order to establish this design procedure, and consequently the final design procedure is proposed as a strategy requiring only linear structural analysis, while acceptance criteria of nonlinear analysis is implicitly satisfied.

• Journal of Digital Convergence
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• v.14 no.1
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• pp.131-139
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• 2016

Given social problems of service addiction such as mobile messenger services(MMSs), many studies on service management and information systems have examined the negative outcomes of service addiction. MMS addiction significantly influences user's health and academic performance. In this regard, this study investigated the effects of MMS addiction on user's health and academic performance problems. We posit personal traits and service features as key antecedents of MMS addiction. The research framework was tested by using survey data collected from 162 university students who have frequently used Kakaotalk. The analysis results found that MMS addiction significantly influences users' health and academic performance problems. The findings of this study indicate that self-esteem and self-control play an important role in generating MMS addiction. While attention significantly affects MMS addiction, social relationship formation and perceived enjoyment are not significantly associated with MMS addiction. The analysis results help MMS providers and government establish policies or guidelines to induce healthy MMS use.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.5
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• pp.723-729
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• 2013

This paper presents an parallel type Linear Induction Motor with ununiform airgap for a shallow-depth underground train with 100‰ grade and 15 m curvature. This parallel type LIM has enough gradability but has inherently ununiform airgap between center and end parts. Consequently, performance when the train passes curved section should be considered with transient analysis. Moreover, general parallel operation, 1C2M which is usually used for train operation, deteriorates LIM performance because of different line velocity between inner and outer LIMs. Transient analysis has many problems such as huge model, lots of meshes, very long calculation time, truncation error and so on. This paper has presented a novel technique using equivalent linear rotating model in order to solve these problems and has analyzed parallel type LIM by using the proposed technique. Finally, LIM performance according to independent operating control has been investigated.

• International Journal of Human Ecology
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• v.11 no.2
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• pp.25-37
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• 2010

This study examined the relationships between parenting styles, academic achievement, and behavioral adjustment of adolescents in Korea. Using a sample of 181 parents and their children (13-15 years old), parents completed the Parental Authority Questionnaire and adolescents filled out the Youth Behavior Checklist (CBCL) and provided their school grades. Factor analysis was conducted on the PAQ to confirm the psychometric properties. Hierarchical regression analysis was computed to determine the relationship between maternal and paternal parenting styles, academic performance, and children's internalizing and externalizing behaviors. Regression analysis revealed that mother's authoritative parenting style was positively related with adolescents' grades in English. However, father's permissive was negatively related with adolescents' grades in English, Mathematics, and Science. Mother's permissive parenting styles showed negative effects of internalizing and externalizing behavior problems whereas father's permissive parenting styles showed positive effects of internalizing and externalizing behavior problems.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.3
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• pp.778-798
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• 2014

This paper proposes a novel exposed-terminal-eliminated medium access control (ETE-MAC) protocol by combining channel reservation, collision avoidance and concurrent transmissions to improve multi-access performance of the multihop wireless networks. Based on the proposed slot scheduling scheme, each node senses the control channel (CCH) or the data channel (DCH) to accurately determine whether it can send or receive the corresponding packets without collisions. Slot reservation on the CCH can be simultaneously executed with data packet transmissions on the DCH. Therefore, it resolves the hidden-terminal type and the exposed-terminal type problems efficiently, and obtains more spatial reuse of channel resources. Concurrent packet transmissions without extra network overheads are maximized. An analytical model combining Markov model and M/G/1 queuing theory is proposed to analyze its performance. The performance comparison between analysis and simulation shows that the analytical model is highly accurate. Finally, simulation results show that, the proposed protocol obviously outperforms the link-directionality-based dual-channel MAC protocol (DCP) and WiFlex in terms of the network throughput and the average packet delay.

• Journal of Electrical Engineering and Technology
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• v.12 no.4
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• pp.1417-1426
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• 2017

Power system analysis, Non-Convex Economic Dispatch (NED) is considered as an open and demanding optimization problem. Despite the fact that realistic ED problems have non-convex cost functions with equality and inequality constraints, conventional search methods have not been able to effectively find the global answers. Considering the great potential of meta-heuristic optimization techniques, many researchers have started applying these techniques in order to solve NED problems. In this paper, a new and efficient approach is proposed based on imperialist competitive algorithm (ICA). The proposed algorithm which is named multi-operator ICA (MuICA) merges three operators with the original ICA in order to simultaneously avoid the premature convergence and achieve the global optimum answer. In this study, the proposed algorithm has been applied to different test systems and the results have been compared with other optimization methods, tending to study the performance of the MuICA. Simulation results are the confirmation of superior performance of MuICA in solving NED problems.

• Proceedings of the Korea Society for Simulation Conference
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• 2001.10a
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• pp.44-49
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• 2001

This paper is concerned with development of a multi-attribute structured decision model. In this study, we used AHP(analytic hierarchy process) and fuzzy set ranking methodology to overcome the multi-attributes structured decision problems ; such as multi-objective, multi-criterion, and multi-attributes. We proposed a 2-step approach : 1) individual evaluation and 2) integration of individual evaluations. In the first step, we define the performance factors and construct ana]isis structure, and in the second step performance evaluation by individual evaluators, and in second step, the results of individual evaluations are integrate. Also we developed a systematic and practical computer program to solve the problems according to the proposed methods. The proposed approach was known to be effective through a set of sample problems.

• Journal of Korean Institute of Industrial Engineers
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• v.22 no.3
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• pp.413-426
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• 1996

Modern society, as a result of high industrial technology, is characterized by a series of mass production, moss consumption and mass disposal. As the mass disposal is known as the major culprit of destroying ecological system of our environment, human prosperity is in turn threatened by this indiscrete activities. Under current industrial technology which pursuit maximum profit, environmental problems could not be solved. This paper proposes recycle manufacturing systems of assemble products as a measure of current non-recycle manufacturing systems. Products are also composed of a number of ports. All parts are represented by a function of time cost performance variable as reuse level. We develop on information systems which give all the information on reused and recycled parts. We try to implement this result on a real fields. We confide ourselves to the contribution to on effective solution of environmental problems and to give profit to assembly manufacturing and consumers.