• Title/Summary/Keyword: mathematics

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An algebraic multigrids based prediction of a numerical solution of Poisson-Boltzmann equation for a generation of deep learning samples (딥러닝 샘플 생성을 위한 포아즌-볼츠만 방정식의 대수적 멀티그리드를 사용한 수치 예측)

  • Shin, Kwang-Seong;Jo, Gwanghyun
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.26 no.2
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    • pp.181-186
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    • 2022
  • Poisson-Boltzmann equation (PBE) is used to model problems arising from various disciplinary including bio-pysics and colloid chemistry. Therefore, to predict a numerical solution of PBE is an important issue. The authors proposed deep learning based methods to solve PBE while the computational time to generate finite element method (FEM) solutions were bottlenecks of the algorithms. In this work, we shorten the generation time of FEM solutions in two directions. First, we experimentally find certain penalty parameter in a bilinear form. Second, we applied algebraic multigrids methods to the algebraic system so that condition number is bounded regardless of the meshsize. In conclusion, we have reduced computation times to solve algebraic systems for PBE. We expect that algebraic multigrids methods can be further employed in various disciplinary to generate deep learning samples.

THE IDEAL CLASS GROUP OF POLYNOMIAL OVERRINGS OF THE RING OF INTEGERS

  • Chang, Gyu Whan
    • Journal of the Korean Mathematical Society
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    • v.59 no.3
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    • pp.571-594
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    • 2022
  • Let D be an integral domain with quotient field K, Pic(D) be the ideal class group of D, and X be an indeterminate. A polynomial overring of D means a subring of K[X] containing D[X]. In this paper, we study almost Dedekind domains which are polynomial overrings of a principal ideal domain D, defined by the intersection of K[X] and rank-one discrete valuation rings with quotient field K(X), and their ideal class groups. Next, let ℤ be the ring of integers, ℚ be the field of rational numbers, and 𝔊f be the set of finitely generated abelian groups (up to isomorphism). As an application, among other things, we show that there exists an overring R of ℤ[X] such that (i) R is a Bezout domain, (ii) R∩ℚ[X] is an almost Dedekind domain, (iii) Pic(R∩ℚ[X]) = $\oplus_{G{\in}G_{f}}$ G, (iv) for each G ∈ 𝔊f, there is a multiplicative subset S of ℤ such that RS ∩ ℚ[X] is a Dedekind domain with Pic(RS ∩ ℚ[X]) = G, and (v) every invertible integral ideal I of R ∩ ℚ[X] can be written uniquely as I = XnQe11···Qekk for some integer n ≥ 0, maximal ideals Qi of R∩ℚ[X], and integers ei ≠ 0. We also completely characterize the almost Dedekind polynomial overrings of ℤ containing Int(ℤ).

Large cylindrical deflection analysis of FG carbon nanotube-reinforced plates in thermal environment using a simple integral HSDT

  • Djilali, Nassira;Bousahla, Abdelmoumen Anis;Kaci, Abdelhakim;Selim, Mahmoud M.;Bourada, Fouad;Tounsi, Abdeldjebbar;Tounsi, Abdelouahed;Benrahou, Kouider Halim;Mahmoud, S.R.
    • Steel and Composite Structures
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    • v.42 no.6
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    • pp.779-789
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    • 2022
  • This work presents a non-linear cylindrical bending analysis of functionally graded plate reinforced by single-walled carbon nanotubes (SWCNTs) in thermal environment using a simple integral higher-order shear deformation theory (HSDT). This theory does not require shear correction factors and the transverse shear stresses vary parabolically through the thickness. The material properties of SWCNTs are assumed to be temperature-dependent and are obtained from molecular dynamics simulations. The material properties of functionally graded carbon nanotube-reinforced composites (FG-CNTCRs) are considered to be graded in the thickness direction, and are estimated through a micromechanical model. The non-linear strain-displacement relations in the Von Karman sense are used to study the effect of geometric non-linearity and the solution is obtained by minimization of the total potential energy. The numerical illustrations concern the nonlinear bending response of FG-CNTRC plates under different sets of thermal environmental conditions, from which results for uniformly distributed CNTRC plates are obtained as benchmarks.

Effect of the variable visco-Pasternak foundations on the bending and dynamic behaviors of FG plates using integral HSDT model

  • Hebali, Habib;Chikh, Abdelbaki;Bousahla, Abdelmoumen Anis;Bourada, Fouad;Tounsi, Abdeldjebbar;Benrahou, Kouider Halim;Hussain, Muzamal;Tounsi, Abdelouahed
    • Geomechanics and Engineering
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    • v.28 no.1
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    • pp.49-64
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    • 2022
  • In this work, the bending and dynamic behaviors of advanced composite plates resting on variable visco-Pasternak foundations are studied using a simple shear deformation integral plate model. The research is carried out with a view to a three-parameter foundation including the influences of the variable Winkler coefficient, the constant Pasternak coefficient and the damping coefficient of the elastic medium. The present theory uses a displacement field with integral terms instead of derivative terms by including also the shear deformation effect without introducing the shear correction factors. The equations of motion for advanced composite plates are obtained using the Hamilton principle. Analytical solutions for the bending and dynamic analysis are deduced for simply supported plates resting on variable visco-Pasternak foundations. Some numerical results are presented to demonstrate the impact of material index, elastic foundation type, and damping coefficient of the foundation, on the bending and dynamic responses of advanced composite plates.

A computational investigation on flexural response of laminated composite plates using a simple quasi-3D HSDT

  • Draiche, Kada;Selim, Mahmoud M.;Bousahla, Abdelmoumen Anis;Tounsi, Abdelouahed;Bourada, Fouad;Tounsi, Abdeldjebbar;Mahmoud, S.R.
    • Steel and Composite Structures
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    • v.41 no.5
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    • pp.697-711
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    • 2021
  • In this work, a simple quasi 3-D parabolic shear deformation theory is developed to examine the bending response of antisymmetric cross-ply laminated composite plates under different types of mechanical loading. The main feature of this theory is that, in addition to including the transverse shear deformation and thickness stretching effects, it has only five-unknown variables in the displacement field modeling like Mindlin's theory (FSDT), yet satisfies the zero shear stress conditions on the top and bottom surfaces of the plate without requiring a shear correction factor. The static version of principle of virtual work was employed to derive the governing equations, while the bending problem for simply supported antisymmetric cross-ply laminated plates was solved by a Navier-type closed-form solution procedure. The adequacy of the proposed model is handled by considering the impact of side-to-thickness ratio on bending response of plate through several illustrative examples. Comparison of the obtained numerical results with the other shear deformation theories leads to the conclusion that the present model is more accurate and efficient in predicting the displacements and stresses of laminated composite plates.

Non-contact Input Method based on Face Recognition and Pyautogui Mouse Control (얼굴 인식과 Pyautogui 마우스 제어 기반의 비접촉식 입력 기법)

  • Park, Sung-jin;Shin, Ye-eun;Lee, Byung-joon;Oh, Ha-young
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.26 no.9
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    • pp.1279-1292
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    • 2022
  • This study proposes a non-contact input method based on face recognition and Pyautogui mouse control as a system that can help users who have difficulty using input devices such as conventional mouse due to physical discomfort. This study includes features that help web surfing more conveniently, especially screen zoom, scroll function, and also solves the problem of eye fatigue, which has been suggested as a limitation in existing non-contact input systems. In addition, various set values can be adjusted in consideration of individual physical differences and Internet usage habits. Furthermore, no high-performance CPU or GPU environment is required, and no separate tracker devices or high-performance cameras are required. Through these studies, we intended to contribute to the realization of barrier-free access by increasing the web accessibility of the disabled and the elderly who find it difficult to use web content.

Researched and Analyzed Variables for Pollution Waters around the "Kosova B" Thermal Power Plant

  • Musliu, Adem;Musliu, Arber;Baftiu, Naim
    • International Journal of Computer Science & Network Security
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    • v.22 no.9
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    • pp.109-116
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    • 2022
  • The energy corporation of Kosovo continuously monitors and analyzes the impact of its own activities on the environment. Regarding the environmental situation, energy corporation of Kosovo- ECK regularly informs and reports objectively to the competent state institutions, local municipal institutions and interested parties. ECK, through numerous contacts with the competent authorities, firstly with different ministers, harmonizes the positions regarding environmental issues in the direction of achieving certain environmental standards or legal requirements in order to gradually be in accordance with them, based on the real possibilities, especially the financial ones. From this point of view, the environmental issue is very sensitive, quite complex and represents one of the biggest challenges of society currently and in the future. The researched variables show a continuous increase in the need for electricity production in Kosovo and this increase in production conditions a wide range of environmental impacts both at the local, regional and global levels. The aim of the work is to reduce the emission of pollutants through the main variables without inhibiting the economic development of the country, i.e. to bring the pollution as a result of the activities of the ECK operation into compliance with the permitted environmental norms. As a result of ECK's operational activities, the following follows: Air pollution mainly as a result of emissions from TCs in the air, transport, etc. Water pollution - as a result of technological water discharges, Land degradation - as a result of surface mining activities of the entire mining area. The purpose of the paper is to research and analyze the main water variables in the area of the Kosova B power plant, which is to determine the degree of their pollution from the activities of the power plants, as well as to assess the real state of surface water quality and control the degree of pollution of these waters. Methodology of the work: The analyzes of the water samples were done in the company Institute "INKOS" JSC by simultaneous methods using different reagents.

Investigation of Dongje School Based on the Primary Historical Data and Geographical Information (일차 사료와 지리 정보를 통한 동제학교에 대한 고찰)

  • Ha, Ki-Tae;Choi, June-Yong;Kim, Kibong
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.36 no.4
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    • pp.105-112
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    • 2022
  • Dongje school (同濟學校), alternately Dongje medical school, is generally recognized as the first modern school for Korean medicine. However, there is very limited information concerning its establishment, duration period, governance, location, and contents for teaching. We found several points which are different from popular opinions through investigating news articles of those days and maps. Dongje school has established on June 1, 1906 and the time of its discontinuance is not clear. The school was founded with the cooperation of three former government officials of the Korean Empire, Eungse Lee (李應世), Piljoo Kang (姜弼周), and Dongho Cho (趙東浩) and many people donated fund for supporting Dongje school. However, there is no evidence of national or royal expenditures for operating the school. Dongje school has been established in 76-6, Seohak hill (西學峴), Yeogyeong-bang (餘慶坊), West county (西署), Seoul and moved to Naesum-si (內贍寺) located in Bongsangsi front village (奉常寺前門洞), Indal-bang (仁達坊), West county, at September 1906. The curriculum of the school comprehends several disciplines including literature in Korean and Chinese, mathematics, foreign language, physics, and Western medicine, as well as Korean medicine. Particularly at that time, they thought both of women and men. To elucidate the issue of the governance of Dongje school regarding the national or royal establishment, more information and extensive studies should be needed.

Career Development of Upper Elementary Students through STEAMS-Based Gardening Programs

  • Jang, Jeungeun;Hong, Jong Won;Kim, Jongyun
    • Journal of People, Plants, and Environment
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    • v.23 no.2
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    • pp.221-231
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    • 2020
  • Since elementary school is a time in which basic concepts like attitudes and mindsets about careers are formed, career education is very important to elementary school students. This study was conducted to investigate the effects of a gardening program applying the academic disciplines of Science, Technology, Engineering, Arts, Mathematics, and Society (STEAMS) on developing career education for elementary school students. In order to determine the effectiveness of the program on career development of elementary school students, this study was conducted with 28 upper elementary students in the experimental group who participated in the gardening program, and 30 upper elementary students in the control group who did not. The program was comprised of total 8 sessions, one session per week, with various garden activities. The career development scores of the two groups before and after the program were comparatively analyzed. Before the program, the experimental group had significantly lower scores for career development than the control group. After 8 weeks of the program, the control group did not show any changes in career development, while the experimental group that participated in the program showed a significant increase in career development, resulting in no difference in career development between the two groups after the program. Therefore, the program has positive effects on improving career development of upper elementary students who previously had insufficient career development. Overall, the program had positive effects on career development of upper elementary students, and further research is needed to systematically promote the STEAMS-based gardening program to promote interest and understanding of students by associating plant-based gardening activities with various subjects such as science, art, and social studies.

Changes and Issues Regarding the Elementary Science Curriculum: Focusing on Physics (초등 과학 교육과정의 변화와 쟁점 - 물리 영역을 중심으로 -)

  • Byun, Taejin
    • Journal of Korean Elementary Science Education
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    • v.41 no.2
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    • pp.217-235
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    • 2022
  • This study aimed to analyze the changes in the physics curriculum of elementary schools over the past years and to discuss the issues faced by the science curriculum for elementary education prior to the next curriculum revision. We analyzed changes in the elements of the contents from the 7th curriculum to the 2015 revised curriculum and reviewed studies conducted after the revision in 2015. Additionally, three professors majoring in physics education discussed the results of the curriculum analysis. The result indicates that content of the physics curriculum for elementary education was generally reduced after the 7th curriculum. Specifically, difficult concepts were omitted or designated to a higher school level. Concerns related to the science curriculum pertain to the content adequacy and difficulty of the current curriculum, its relationship with mathematics, connection between the Nuri curriculum and the integrated curriculum for the 1st and 2nd grades, and the achievement standard predicate problem.