• Korean Journal of Mathematics
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• v.27 no.2
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• pp.417-423
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• 2019

In the paper, by virtue of the $Fa{\grave{a}}$ di Bruno formula, properties of the Bell polynomials of the second kind, and the Lah inversion formula, the author simplifies coefficients in a family of ordinary differential equations related to the generating function of the Mittag-Leffler polynomials.

• Journal of the Chungcheong Mathematical Society
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• v.33 no.4
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• pp.445-468
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• 2020

A long-time behavior of global solutions for a dispersive-dissipative equation with time-dependent damping terms is investigated under null Dirichlet boundary condition. By virtue of an appropriate new Lyapunov function and the Lojasiewicz-Simon inequality, we show that any global bounded solution converges to a steady state and get the rate of convergence as well, when damping coefficients are integrally positive and positive-negative, respectively. Moreover, under the assumptions on on-off or sign-changing damping, we derive an asymptotic stability of solutions.

• Korean Journal of Mathematics
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• v.30 no.3
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• pp.503-512
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• 2022

In this paper, we are concerned with the problem of locating the zeros of regular polynomials of a quaternionic variable with quaternionic coefficients. We derive new bounds of Eneström-Kakeya type for the zeros of these polynomials by virtue of a maximum modulus theorem and the structure of the zero sets in the newly developed theory of regular functions and polynomials of a quaternionic variable. Our results generalize some recently proved results about the distribution of zeros of a quaternionic polynomial.

• The Pure and Applied Mathematics
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• v.29 no.1
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• pp.31-35
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• 2022

In the note, by virtue of Abel's theorem and Abel's limit theorem in the theory of power series, the author provides three proofs for a sum of an alternating series involving central binomial numbers.

• Journal of Electrical Engineering and information Science
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• v.1 no.1
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• pp.77-81
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• 1996

Considering the human visual masking property, a modified relationship between the activity function and the visibility threshold is developed. This leads to a novel objective appraisal method for blocking effects in a lossy subimage coding by virtue of the human visual sensitivity. The appraisal criterion is examined using a series of reconstructed images that are DCT-coded at various bit rates. Experimental results show that the presented blocking effect measure well agrees with the subjective ranking.

• The Journal of the Korea Contents Association
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• v.12 no.10
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• pp.72-81
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• 2012

From the viewpoint of invigorating Korean film-market, the commercial success of films can be regarded as a very important virtue. Such marketability of films will be determined at the stage of planning and development before that of film-making. In order for ideas and scenarios which are the foundation of film-making to have any commercial virtue, a commercial verification at this stage should intervene, which should be the basis of the understanding a lot of texts and the trends in the entire culture. It is the very time that the efforts for improving the stage of planning and development and certain alternatives are needed for the qualitative growth of Korean films and the systematic development of their industrial aspects, for any efficient alternatives for the stage of planning and development will bring about an important result that the commercial success of Korean films expand the meaning into the domains of creativeness and artistry.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.8
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• pp.1449-1458
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• 2006

Electronic Navigational Charts (ENCs) are digital charts which contain a great variety of data on coast and sea regions. Although they contain much information that ordinary people are interested in, there is no easy way to access because they are coded in the specialized data forma, and can be visualized by using specialized system. Therefore, supporting systems need to be developed for ordinary people to easily access ENCs. This paper proposes a framework for the ENC systems based on the Web. It relies on quite general standards such as Ceography Markup Language (GML) and Scalable Vector Graphics (SVG). In the framework, ENCs coded in S-57 format are first translated into GML to be stored in a database. Once the database is built, users can request to the database what they want. According to the user request, relevant data are retrieved, and then translated into SVG to be displayed on the Web browser. By using the framework, ordinary people may easily access coast and sea information contained in the ENCs. Furthermore, the framework may provide interoperability by virtue of XML-based standards such as GML and SVG, and efficiency by virtue of database. To validate the feasibility of proposed framework, a prototype system is developed and tested.

• Journal of Families and Better Life
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• v.25 no.1 s.85
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• pp.101-112
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• 2007

In this paper, 274 traditional fairy tales of South and North Korea were selected for research. The research was performed using a content analysis chart, and found differences in the number of characters, how ideology and social setting affect categorization of the characters, and what values are represented in the fairy tails of each country. Analysis of the general characteristics of traditional fairy tales of South and North Korea shows that South Korean traditional fairy tales have more cases where $1{\sim}4$ characters appear. In North Korean fairy tales, 5 or more characters generally appear. Analysis of the categories of characters in traditional fairy tales of South and North Korea found that characters fall into categories of family, friend and tutor, village, and the native country more often in South Korean fairy tales than in North Korean fairy tales. Character categorizations of county and foreign countries are found more often in North Korean fairy tales. In particular, the difference in character categorization of family, friend and tutor, and county shows that different ideology and social setting affected categories of characters. Research on traditional fairy tales of South and North Korea shows that traditional fairy tales of South Korea have chosen self-respect, self-restraint, fidelity(responsibility), understanding others, manners and honesty as themes more often than those of North Korea and subjects such as frugality, sharing, order and rules, cooperation and patriotism(ecosystem protection) we found more often in those of North Korea.

• Structural Engineering and Mechanics
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• v.75 no.6
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• pp.747-769
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• 2020

This paper provides a semi-analytical approach to investigate the variations of 3D displacement components, electric potential, stresses, electric displacements and transverse vibration frequencies in laminated piezoelectric composite plates based on the scaled boundary finite element method (SBFEM) and the precise integration algorithm (PIA). The proposed approach can analyze the static and dynamic responses of multilayered piezoelectric plates with any number of laminae, various geometrical shapes, boundary conditions, thickness-to-length ratios and stacking sequences. Only a longitudinal surface of the plate is discretized into 2D elements, which helps to improve the computational efficiency. Comparing with plate theories and other numerical methods, only three displacement components and the electric potential are set as the basic unknown variables and can be represented analytically through the transverse direction. The whole derivation is built upon the three dimensional key equations of elasticity for the piezoelectric materials and no assumptions on the plate kinematics have been taken. By virtue of the equilibrium equations, the constitutive relations and the introduced set of scaled boundary coordinates, three-dimensional governing partial differential equations are converted into the second order ordinary differential matrix equation. Furthermore, aided by the introduced internal nodal force, a first order ordinary differential equation is obtained with its general solution in the form of a matrix exponent. To further improve the accuracy of the matrix exponent in the SBFEM, the PIA is employed to make sure any desired accuracy of the mechanical and electric variables. By virtue of the kinetic energy technique, the global mass matrix of the composite plates constituted by piezoelectric laminae is constructed for the first time based on the SBFEM. Finally, comparisons with the exact solutions and available results are made to confirm the accuracy and effectiveness of the developed methodology. What's more, the effect of boundary conditions, thickness-to-length ratios and stacking sequences of laminae on the distributions of natural frequencies, mechanical and electric fields in laminated piezoelectric composite plates is evaluated.

• Korean Journal of Logic
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• v.14 no.1
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• pp.77-102
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• 2011

This paper is about the problems that Quine's criterion of ontological commitment creates for Nominalists. Quine's clear criterion of ontological commitment, summarized as "to be is to be the value of a variable", means that when we accept a sentence to be true, we are committed to the existence of things that must exist for the sentence to be true. The criterion causes problems for Nominalists. According to Quine's criterion, Nominalists who consider "Humility is a virtue" as true should accept the existence of the property, humility. However, Nominalists are reluctant to accept that properties such as humility exist, although they wish to accept what is meant by "humility is a virtue". The way out of this predicament is presenting a paraphrase which delivers what Nominalists wanted to say through the original sentence without ontological commitment to the property. Several attempts were made to paraphrase such sentences, only to fail. In this paper, successful paraphrases will be presented to cope with previously discussed difficulties. Beforehand, several issues involved in the Quine's criterion will be clarified. Also, Lewis's critical objection that we should give up the business of paraphrase will be discussed.