• Communications of the Korean Mathematical Society
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• v.34 no.1
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• pp.43-54
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• 2019

Let R be a ring with identity and J(R) denote the Jacobson radical of R, i.e., the intersection of all maximal left ideals of R. A ring R is called J-symmetric if for any $a,b,c{\in}R$, abc = 0 implies $bac{\in}J(R)$. We prove that some results of symmetric rings can be extended to the J-symmetric rings for this general setting. We give many characterizations of such rings. We show that the class of J-symmetric rings lies strictly between the class of symmetric rings and the class of directly finite rings.

• Kyungpook Mathematical Journal
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• v.62 no.4
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• pp.729-736
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• 2022

To help solving intractable nonlinear evolution equations (NLEEs) of waves in the field of fluid dynamics we develop an algorithm to find new high order solutions of the class of Abel, Bernoulli, Chini and Riccati equations of the form y' = ayⁿ + by + c, n > 1, with constant coefficients a, b, c. The role of this class of equations in NLEEs is explained in the introduction below. The basic algorithm to compute the coefficients of the power series solutions of the class, emerged long ago and is further developed in this paper. Practical application for hitherto unknown solutions is exemplified.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.11a
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• pp.63-64
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• 2022

In this study, the quality of mineral admixture, Comparison of blast-furnace slag(BS) and fly ash(FA)in Korea and China. In the case of BS, Korea is mainly classified into 1 type to 4 types according to the specific surface area, whereas China is classified into S105, 95, and 75 according to the activity index of 28 days of age. In the case of FA, Korea is like BS, is mainly classified into types 1 to 4 according to specific surface area, whereas China is classified into F, C (class F, class C) by ingredients and class I, II, and III according to powder and ignition loss.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.339-340
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• 2012

• Korean Journal of Mathematics
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• v.20 no.4
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• pp.451-461
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• 2012

B.C. Berndt has established many relations between various infinite series using a transformation formula for a large class of functions, which comes from a more general class of Eisenstein series. In this paper, continuing his study, we find some infinite series identities.

• Communications of the Korean Mathematical Society
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• v.34 no.4
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• pp.1157-1162
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• 2019

In this paper, we extend the study of general convergence theorems for the Picard iteration of Proinov contraction from the class of continuous mappings to the class of discontinuous mappings. As a by product we provide a new affirmative answer to the open problem posed in [20].

• Communications of the Korean Mathematical Society
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• v.39 no.2
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• pp.267-278
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• 2024

In this paper, we continue to explore an idea presented in [3] and introduce a new class of matrix rings called staircase matrix rings which has applications in noncommutative ring theory. We show that these rings preserve the notions of reduced, symmetric, reversible, IFP, reflexive, abelian rings, etc.

• Journal of The Korean Association For Science Education
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• v.40 no.2
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• pp.227-236
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• 2020

This study examines the change in students' science attitude and the growth of their core competencies through science classes emphasizing digital literacy. To this end, we conducted a study on 116 first graders in C middle school in the C region, and entered a science class that emphasized digital literacy of 35 classes. First, as a result of examining the effect on science attitude, a statistically significant change (p<.05) was observed. The effect size for each subregion ranged from 0.67 to 1.52. Second, there were no differences in the overall frequency of growth perception according to the type of class that emphasized digital literacy. However, in the analysis of core competencies, Web-based classes did not show a large difference in frequency by core competencies, whereas high-tech classes were slightly different by core competencies. This is an implication for science education, and it is necessary to increase the utilization of science classes that emphasize digital literacy.

• The Transactions of the Korea Information Processing Society
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• v.6 no.6
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• pp.1542-1555
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• 1999

This paper proposes an algorithm for class hierarchies which can optimize member data and member function. This algorithm considers single/multiple inheritance, static/dynamic binding, overloading/overriding, pure virtual/virtual function, and constructor on the hierarchy of C++ class. We need to eliminate unused function that possesses many component element, because the program uses a limited of function in class hierarchies. Previous works on slicing mainly focused on selecting output data and including the related program statement. It was consists of structured programming language and also centralized on error detection, maintenance, and flexible testing. In this paper, we extend to the object-oriented language, makes a linked-table for objects to raise the efficiency of information management, and proposes necessary algorithm for optimizing system Through this process, we can obtain the simplification of program code and the progress of system performance by eliminating unused member data and member function.

• Journal of Welding and Joining
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• v.28 no.5
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• pp.69-74
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• 2010

Irradiation behavior of the reactor pressure vessel SA508 class 3 steel weld metals was examined by Charpy V Notch impact specimens. The specimens were exposed to a fluence of $2.8{\times}1019$ neutrons(n)/$cm^2$(E>1 MeV) at $288^{\circ}C$. The irradiation damage of weld metal was evaluated by comparison between unirradiated and irradiated specimens in terms of absorbed energy and lateral expansion. The specimens for neutron irradiation were welded by submerged arc welding process at a heat input of 3.2 kJ/mm which showed good toughness in terms of weld microstructure, absorbed energy and lateral expansion. The post-irradiation Charpy V notch 41J and 68J transition temperature elevation were $65^{\circ}C$ and $70^{\circ}C$, respectively. This elevation was accompanied by a 20% reduction in Charpy V notch upper shelf energy level. The lateral expansion at 0.9mm irradiated Charpy specimens showed temperature elevation of $65^{\circ}C$ and was greatly decreased due to radiation damage.