• Kyungpook Mathematical Journal
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• v.18 no.1
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• pp.53-59
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• 1978

The coefficient problems of univalent functions was given by Bieberbach. As is well-known, Koebe distortion theorem has close connection with the coefficient problems of univalent functions. It is purpose of this paper to give the distortion theorems for fractional integral and derivative of univalent functions.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2039-2042
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• 2008

Recently, Electronic & Electrical Products have problems how to reduce heat in trend reducing size and increasing speed. heat pipes worked by latent heats can solve problems for effective and quiet electronic applications. Heat Pipes have to be suitably designed for the external conditions due to showing optimum performance. it has influence on efficiency of heat pipes to the exterior structure changed by length, bending angle, diameter. Designing heat pipes has depended on experience from trial and error. this method wasted too many resources, but can't guarantee efficiency. to prevent those wastes, this study aims at making the thermal transfer coefficient predicting efficiency. In this study, the thermal transfer coefficient has been made from experimental results that used variables - lengths between heat source and radiation, bending angles, diameters of heat pipes. variables become non-dimensional in modeling process for making the coefficient.

• Journal of Information Processing Systems
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• v.14 no.5
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• pp.1215-1224
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• 2018

Interval-valued neutrosophic hesitant fuzzy set (IVNHFS) is an extension of neutrosophic set (NS) and hesitant fuzzy set (HFS), each element of which has truth membership hesitant function, indeterminacy membership hesitant function and falsity membership hesitant function and the values of these functions lie in several possible closed intervals in the real unit interval [0,1]. In contrast with NS and HFS, IVNHFS can be more flexibly used to deal with uncertain, incomplete, indeterminate, inconsistent and hesitant information. In this study, I propose the novel correlation coefficient of IVNHFSs and my paper discusses its properties. Then, based on the novel correlation coefficient, I develop an approach to deal with multi-attribute decision-making problems within the framework of IVNHFS. In the end, a practical example is used to show that the approach is reasonable and effective in dealing with decision-making problems.

• International Commerce and Information Review
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• v.18 no.4
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• pp.55-78
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• 2016

In this study, service quality attributes of uTradeHub were classified based on the Kano model, and quality attributes that should be managed in priority to improve the service quality of uTradeHub were investigated using Timko's customer satisfaction coefficient(CSC) and average satisfaction coefficient(ASC). The results of the study are summarized as follows. First, as a result of classifying service quality attributes based on Kano model, 12 one dimensional qualities, 5 must-be qualities, 2 indifferent qualities were deducted, and many quality attributes of uTradeHub service were confirmed to be one dimensional quality to which is needed to be paid attention and paid more detailed attention to enhance service quality. Second, in the analysis result using Timko's customer satisfaction coefficient, "post processing for problems and complaints", "cost reduction", "efficiency of business processing" were ranked in the top of satisfaction coefficient, and they found to be quality attributes that customer satisfaction increases when service quality was satisfied. While, "post processing for problems and complaints", "interaction", "ability to respond promptly when problems occur" were ranked in the top of unsatisfaction coefficient, and they were analysed to be quality attributes that customer complaints increase when service quality was unsatisfied. Third, in the result of analyzing the quality attributes that should be managed in priority to improve the service quality of uTradeHub based on the average satisfaction coefficient(ASC), "post processing for problems and complaints", "cost reduction", "useful information" were ranked in the top 3, and they were classified as quality attributes that the satisfaction level increases more when they are improved than now, but the satisfaction level decreases when they are worsen.

• Journal of the Korean Society for Precision Engineering
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• v.9 no.4
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• pp.90-99
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• 1992

In resent year Laser Speckle and its development have enabled surface deformation of engineering components and materials to be interferometrically examined. Laser Speckle- Pettern Interferometry Method is a very useful method for measuring In-plane components of displacement. In measuring thermal expansion coefficient, the various problems generated were established, and the measuring limitation examined. Metarial INCONEL 601 was used in experiments. Specimen was heated to the high temperature(100$0^{\circ}C$) by diong current to the direct two specimen. Then, those problems appear to the influence of back-ground radiation by the heated specimen, the influence by air turbulence, the oxidation of specimen. The color monitor and interference filter prevented the back-ground radiation by rad heat. The oxidation occuring in specimen itself was not generated by the being acid-proof excellence of material INCONEL 601. Yet, in this experiments, the serious problems are the oxidation of specimen and influence by air turbulence. By more reserching these problems forward, it is helpful that the thermal expansion coefficient of many materials is directly measured under high temperature.

• The Mathematical Education
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• v.45 no.1 s.112
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• pp.97-104
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• 2006

The purpose of this study is to extract some suggestions in developing the elementary students' abilities to solve the fundamental mathematical problems by analyzing the degree of the correlation between the fundamental mathematical capability and the reading capability of the elementary 3th graders. In order to achieve this goal, this article analyzed the correlation between the fundamental mathematical capability and the reading capability on the basis of the studying result about the diagnostic evaluation conducted on 20,556 elementary 3th graders by the KICE as a national level basic scholastic achievement evaluation. The coefficient of correlation between the fundamental mathematical capability and the reading capability was .621. As such, it shows that the reading capability plays an important role in solving the fundamental mathematical problems. Particularly, the coefficient of correlation between the corollary arguments and the problem solving ability and the reading capability was the highest among the sub-capabilities of fundamental mathematical capability. In addition, judging from the result that the coefficient of correlation between the practical understanding capability and the solving capability of the fundamental mathematical problems was .528, it informs that the practical understanding capability takes an' important part in developing the fundamental mathematical capability of the elementary students. The results of this study support the hypothesis that the understanding capability plays the very important role in solving the fundamental mathematical problems. In particular, the results suggest that it is necessary that the pupils should be simultaneously supported not only by the capability of the mathematical basis, but also by the reading capability, especially the practical understanding capability about the problems, in order to develop the capability to solve the fundamental mathematical problems.

• Transactions of Materials Processing
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• v.15 no.9 s.90
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• pp.679-685
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• 2006

New method for evaluation of heat transfer coefficient is proposed. In general, many researchers have been studied about inverse problem in order to calculate the heat transfer coefficient on three-dimensional heat conduction problem. But they can get the time-dependent heat transfer coefficient only through inverse problem. In order to acquire temperature-dependent heat transfer coefficient, it requires much time for numerous repetitive calculation and inconvenient manual modification. In order to solve these problems, we are using the SQP(Sequential Quadratic Programming) as an optimization algorithm. When the temperature history is given by experiment, the optimization algorithm can evaluate the temperature-dependent heat transfer coefficient with automatic repetitive calculation until difference between calculated temperature history and experimental ones is minimized. Finally, temperature-dependent heat transfer coefficient evaluated by developed program can used on various heat transfer problem.

• Proceedings of the KSR Conference
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• 2004.06a
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• pp.613-618
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• 2004

Is confirming safety of derailment when wish to develop new vehicles or upgrade running speed of vehicles. This means the measure of wheel load and lateral force that act between wheel and rail. So far, problem in continuous measuring method of derailment coefficient was sensitivity decline and noise growth. This research supplemented these problems by composition of new bridge circuit.

• Journal of applied mathematics & informatics
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• v.20 no.1_2
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• pp.17-34
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• 2006

Inverse coefficient identification problems associated with the fourth-order Sturm-Liouville operator in the steady state Euler-Bernoulli beam equation are investigated. Unlike previous studies in which spectral data are used as additional information, in this paper only boundary information is used, hence non-destructive tests can be employed in practical applications.

• Structural Engineering and Mechanics
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• v.17 no.5
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• pp.671-690
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• 2004

A meshless method with novel variation of point collocation by finite mixture approximation is developed in this paper, termed the meshless finite mixture (MFM) method. It is based on the finite mixture theorem and consists of two or more existing meshless techniques for exploitation of their respective merits for the numerical solution of partial differential boundary value (PDBV) problems. In this representation, the classical reproducing kernel particle and differential quadrature techniques are mixed in a point collocation framework. The least-square method is used to optimize the value of the weight coefficient to construct the final finite mixture approximation with higher accuracy and numerical stability. In order to validate the developed MFM method, several one- and two-dimensional PDBV problems are studied with different mixed boundary conditions. From the numerical results, it is observed that the optimized MFM weight coefficient can improve significantly the numerical stability and accuracy of the newly developed MFM method for the various PDBV problems.