• Journal of applied mathematics & informatics
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• v.6 no.1
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• pp.253-264
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• 1999

In this paper we introduce and study a new class of vari-ational inequalities which are called the generalized strongly nonlin-ear quasi-variational inequalities. An algorithm for finding the ap-proximate solution of generalized strongly nonlinear quasi-variational inequalities is also given. These variational inequalities include the previously known classes of variational inequalities as special cases.

• Journal of applied mathematics & informatics
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• v.9 no.1
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• pp.15-26
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• 2002

In this paper, we suggest and analyze a class of resolvent dynamical systems associated with mixed variational inequalities. We study the globally asymptotic stability of the solution of the resolvent dynamical systems for the pseudomonotone operators. We also discuss some special cases, which can be obtained from our main results.

• Kyungpook Mathematical Journal
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• v.46 no.2
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• pp.211-217
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• 2006

In this paper, we have shown that the convergence of one-step, two-step and three-step iterations is equivalent, which are known as Mann, Ishikawa and Noor iteration procedures, for a special class of Lipschitzian operators defined in a closed, convex subset of an arbitrary Banach space.

• Bulletin of the Korean Mathematical Society
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• v.61 no.1
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• pp.13-27
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• 2024

A regular t-balanced Cayley map on a group Γ is an embedding of a Cayley graph on Γ into a surface with certain special symmetric properties. We completely classify regular t-balanced Cayley maps for a class of split metacyclic 2-groups.

• Journal of the Korean Operations Research and Management Science Society
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• v.38 no.1
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• pp.139-152
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• 2013

The purpose of this study is to claim the validity of tuning the architecture of neural network models for multi-class classification. A neural network model for multi-class classification is basically constructed by building a series of neural network models for binary classification. Building a neural network model, we are required to set the values of parameters such as number of hidden nodes and weight decay parameter in advance, which draws special attention as the performance of the model can be quite different by the values of the parameters. For better performance of the model, it is absolutely necessary to have a prior process of tuning the parameters every time the neural network model is built. Nonetheless, previous studies have not mentioned the necessity of the tuning process or proved its validity. In this study, we claim that we should tune the parameters every time we build the neural network model for multi-class classification. Through empirical analysis using wine data, we show that the performance of the model with the tuned parameters is superior to those of untuned models.

• The Journal of the Korea Contents Association
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• v.11 no.8
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• pp.499-511
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• 2011

The purpose of this paper was to investigate differences in middle school student's after school satisfaction according to the type and the degree of flow of after school. For the purpose of this paper, a survey was conducted including a questionnaire consisting of a general characteristic of the study object, a general characteristic of the after school class, learning-flow scale, and after school satisfaction scale. The subjects were 382 students who were selected at random from middle school students. Cronbach' ${\alpha}$ and MANOVA were employed for data analysis. The results were as follows: First, the students with special-ability aptitude class were more satisfied for after school instructors than the students with subject class. Second, the students with the degree of high learning-flow showed higher satisfaction in after school class curriculum, instructors, and educational facility than the degree of low learning-flow students. Third, among the students who were high in learning-flow, the students with special-ability aptitude class were more satisfied with after-school class curriculum and educational facility compared to the students with subject class.

• Journal of applied mathematics & informatics
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• v.32 no.1_2
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• pp.211-225
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• 2014

A new class of smoothing functions is introduced in this paper, which includes some important smoothing complementarity functions as its special cases. Based on this new smoothing function, we proposed a smoothing Newton method. Our algorithm needs only to solve one linear system of equations. Without requiring the nonemptyness and boundedness of the solution set, the proposed algorithm is proved to be globally convergent. Numerical results indicate that the smoothing Newton method based on the new proposed class of smoothing functions with ${\theta}{\in}(0,1)$ seems to have better numerical performance than those based on some other important smoothing functions, which also demonstrate that our algorithm is promising.

• Communications of the Korean Mathematical Society
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• v.13 no.2
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• pp.393-403
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• 1998

We consider $M_1,M_2/M/1$ retrial queues with two classes of customers in which the service rates depend on the total number or the customers served since the beginning of the current busy period. In the case that arriving customers are bloced due to the channel being busy, the class 1 customers are queued in the priority group and are served as soon as the channel is free, whereas the class 2 customers enter the retrical group in order to try service again after a random amount of time. For the first $N(N \geq 1)$ exceptional services model which is a special case of our model, we derive the joint generating function of the numbers of customers in the two groups. When N = 1 i.e., the first exceptional service model, we obtain the joint generating function explicitly and if the arrival rate of class 2 customers is 0, we show that the results for our model coincide with known results for the M/M/1 queues with smart machine.

• Journal for History of Mathematics
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• v.28 no.5
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• pp.233-248
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• 2015

Year 2014 was very special to Korean mathematical society. Year 2014 was the Mathematical Year of Korea, and the International Congress of Mathematicians "ICM 2014" was held in Seoul, Korea. The year 2014 was also the 330th anniversary year of the birth of Joseon mathematician Hong JeongHa. He is one of the best, in fact the best, of Joseon mathematicians. So it is worth celebrating his birth. Joseon dynasty adopted a caste system, according to which Hong JeongHa was not in the higher class, but in the lower class of the Joseon society. In fact, he was a mathematician, a middle class member, called Jungin, of the society. We think over how Hong JeongHa was able to write his mathematical book GuIlJib in Joseon dynasty.

• Special Issue of the Society of Naval Architects of Korea
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• 2005.06a
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• pp.57-62
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• 2005

STX shipbuilding Co,. Ltd. has been developed a hull form and propeller of medium class container vessel. The present paper deals with numerical calculations and experimental tests for the investigation of wave resistance, viscous resistance and propeller. The characteristics of wave resistance and self propulsion factors are varied in order to find an optimized hull form. The measured results have been compared with computed results by 'WAVIS' The prediction of the caviation occurrence was predicted by 'Opti-pro' and measurement is performed in KRISO.