• Earthquakes and Structures
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• v.5 no.2
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• pp.161-205
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• 2013

We study seismically induced, anti-plane strain wave motion in a non-homogeneous geological region containing tunnels. Two different scenarios are considered: (a) The first models two tunnels in a finite geological region embedded within a laterally inhomogeneous, layered geological profile containing a seismic source. For this case, labelled as the first boundary-value problem (BVP 1), an efficient hybrid technique comprising the finite difference method (FDM) and the boundary element method (BEM) is developed and applied. Since the later method is based on the frequency-dependent fundamental solution of elastodynamics, the hybrid technique is defined in the frequency domain. Then, an inverse fast Fourier transformation (FFT) is used to recover time histories; (b) The second models a finite region with two tunnels, is embedded in a homogeneous half-plane, and is subjected to incident, time-harmonic SH-waves. This case, labelled as the second boundary-value problem (BVP 2), considers complex soil properties such as anisotropy, continuous inhomogeneity and poroelasticity. The computational approach is now the BEM alone, since solution of the surrounding half plane by the FDM is unnecessary. In sum, the hybrid FDM-BEM technique is able to quantify dependence of the signals that develop at the free surface to the following key parameters: seismic source properties and heterogeneous structure of the wave path (the FDM component) and near-surface geological deposits containing discontinuities in the form of tunnels (the BEM component). Finally, the hybrid technique is used for evaluating the seismic wave field that develops within a key geological cross-section of the Metro construction project in Thessaloniki, Greece, which includes the important Roman-era historical monument of Rotunda dating from the 3rd century A.D.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2000.04a
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• pp.265-270
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• 2000

본 연구에서는 EEG 반응을 통하여 향이 인간에 미치는 영향을 평가하였다. 24-26세의 8명의 남성 피험자를 대상으로 국제 기준 전극법에 따라 19 부위에서 EEG를 기록하여 분석하였다. 실험에 사용한 향은 Rose oil bulgarian, Lemon oil misitano, Jasmin abs, Laverder iol france (KIMEX co. Ltd) 등 4가지의 천연오일을 사용하였다. 향에 대한 선입견을 배제하고 각 피실험자별로 주관적 평가를 통하여 가장 쾌하게 느낀 향이 제시되었을 때의 뇌파와 무향 상태 뇌파에서 $\alpha$/$\beta$ 대역의 power spectrum 비를 구하여 비교하였다. 무향 상태에 비해 각 피실험자별로 가장 쾌하게 느낀 향을 제시했을 때 F3, Fz, F4, T4 부분에서 $\alpha$/$\beta$ 대역의 power spectrum 비의 통계적으로 유의한 증가를 관찰할 수 있었으며 이는 $\alpha$/$\beta$ 대역의 power spectrum 비가 향의 쾌도를 측정하는 하나의 새로운 척도가 될 수 있음을 시사한다.

• Bulletin of the Korean Mathematical Society
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• v.51 no.3
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• pp.911-922
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• 2014

In the present article we study a special class of surfaces in the four-dimensional Euclidean space, which are one-parameter systems of meridians of the standard rotational hypersurface. They are called meridian surfaces. We show that a meridian surface has a harmonic Gauss map if and only if it is part of a plane. Further, we give necessary and sufficient conditions for a meridian surface to have pointwise 1-type Gauss map and find all meridian surfaces with pointwise 1-type Gauss map.

• Bulletin of the Korean Mathematical Society
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• v.51 no.3
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• pp.831-845
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• 2014

In this paper, we obtain new generating functions involving families of pairs of inverse functions by using a generalization of the Srivastava's theorem [H. M. Srivastava, Some generalizations of Carlitz's theorem, Pacific J. Math. 85 (1979), 471-477] obtained by Tremblay and Fug$\grave{e}$ere [Generating functions related to pairs of inverse functions, Transform methods and special functions, Varna '96, Bulgarian Acad. Sci., Sofia (1998), 484-495]. Special cases are given. These can be seen as generalizations of the generalized Bernoulli polynomials and the generalized degenerate Bernoulli polynomials.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.5 no.1
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• pp.35-39
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• 2005

We apply estimations of the intuitionistic fuzzy sets on the basis of which some amendments may be undertaken.

• Research in Mathematical Education
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• v.14 no.1
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• pp.1-10
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• 2010

The paper focuses on a type of mathematics competence noted as synthetic. It is needed for success in multiple choice competition problems and it is crucial for the further development of advanced school students. The concept of synthetic competence includes a large fraction of mathematical competences, but also competences and skills related to informatics and linguistics. The general structure of a multiple choice competition is considered as the first level of assessment of the mathematics component of the synthetic competence. As the second level under consideration is the set of complex tasks in a competition test any of which is a bouquet of ideas. Our standpoint on the didactic specifics and goals of the two levels in perspective of the gifted education is briefly presented in the article and some examples are given.

• Computers and Concrete
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• v.4 no.2
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• pp.157-166
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• 2007

The paper considers a theoretical model to study sulfate ion diffusion in saturated porous media - cement based mineral composites, accounting for simultaneous effects, such as filling micro-capillaries (pores) with ions and chemical products and liquid push out of them. Pore volume change and its effect on the distribution of ion concentration within the specimen are investigated. Relations for the distribution of the capillary relative radius and volume within the composite under consideration are found. The numerical algorithm used is further completed to consider capillary size change and the effects accompanying sulfate ion diffusion. Ion distribution within the cross section and volume of specimens fabricated from mineral composites is numerically studied, accounting for the change of material capillary size and volume. Characteristic cases of 2D and 3D diffusion are analyzed. The results found can be used to both assess the sulfate corrosion in saturated systems and predict changes occurring in the pore structure of the composite as a result of sulfate ion diffusion.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.4 no.2
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• pp.125-128
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• 2004

Using the theory of Generalized Nets we have modelled the information exchange within the electronic archives of an idealized univerity Intranet.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2000.11a
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• pp.44-47
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• 2000

본 연구에서는 향이 인간에 미치는 영향을 EEG의 시계열 분석을 통해 알아보았다. 피험자는 20대 초반의 후각자애가 없는 30명(남녀 각각 15명)을 대상으로 하여, 국제 기준 전극법을 사용하여 Fz과 Cz에서 뇌파를 기록하였다. 100%의 Rose oil Bulgarian, Lemon oil Mistitano, Jasmine abs, Lavender oil France, Peppermint oil을 실험 시약으로 사용하였다. 각 향 자극에 대하여 1분 동안의 측정을 10초 간격으로 구분하여 $\alpha/(\alpha+\beta)$ 비와 $\beta/(\alpha+\beta)$ 대역의 비를 비교 분석하였다. 30초까지는 안정과 향 자극간의 차이가 증대되는 성향을 보였으나 50초부터는 감소되는 경향을 보였다. 본 연구를 통해 향간의 차이가 자극제시 후 30초 일 때 가장 큰 것으로 나타났다고 이 시간을 기준으로 각 향의 선호도를 분석하였다.

• Proceedings of the Korean Society for Language and Information Conference
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• 2007.11a
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• pp.394-404
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• 2007

This paper explores the nature of multiple sluicing in English, which has two or more remnant wh-phrases in clause edge position. At the beginning part of the paper we argue against Nishigauchi's (1998) and Lasnik's (2007) Gapping analysis of multiple sluicing, which says that two remnant wh-phrases each actually occupies the left and right edge of a clause, with the in-between string of words undergoing Gapping. We rather argue that multiple sluicing in English is the same kind as found in Bulgarian and Serbo-Croatian. In other words, multiple sluicing in English is also derived by multiple wh-fronting which otherwise does not apply. We demonstrate that some important properties of the construction noted by Lmultiple sluicing, multiple wh-movement/fronting, sluicing, TP/IP-deletion, asnik (2007) under the Gapping approach to it can be accounted for in a principled way by our proposed analysis.