• Journal of The Korean Association For Science Education
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• v.13 no.1
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• pp.100-120
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• 1993

Middle school students' conceptual changes on physics, chemistry, biology and earth science concepts which were intentionally selected by researchers had been investigated through traditional teaching and learning by paper and pencil tests and P.O.E. The weak points had been studied by individual interviews about the problems of traditional science classroom teaching after students' testing and learning about science concepts. As results, students' conceptual changes could be hardly found through traditional teaching and learning except several concepts in biology, The weak points of traditional science classroom teaching and learning were as follows: 1) Teachers teach science as finding answers. 2) The conventional science test is not performed to find students' concepts out but to recall simple knowledge or calculus. 3) Students hesitate to ask teacher Questions in science class because of their colleagues' or teachers' blame. These mean that science teachers need specially designed teaching methods on the students' concepts and reseachers had to study about science classroom socialogy, what happened in science classrooms.

• Journal of Science Education
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• v.37 no.2
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• pp.374-388
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• 2013

The purpose of this study was to investigate pre-service physics teachers' perceptions on the physics education major curriculum. We surveyed 15 junior, and 13 senior college students of physics education major in an university in southern part of Korea. Among them, 24 participants(86 %) took the physics 1 course in high school and 22 participants(79 %) chose the physics 1 in their Korea Scholastic Aptitude Test. The responses showed that the most necessary part in pre-service students' learning was the understanding of high school level physics(36 %), and the understanding of introductory level physics(29 %). In the wish list of courses to be open, high school level physics course was ranked first among seven options by 61 % of respondents. Also, there was some concurrence among respondents in opinion of the necessity for understanding introductory physics. Students felt difficulties in understanding it especially owing to the lack of problem solving skill and comprehension. They added that the sufficient explanation of core concepts should be the first action in the innovative plan. Most participants of pre-service physics teachers hoped to have the revised major curriculum which could help their understanding of high school level or introductory level of physics. However, there was a gap of opinions between the group of students with completion of the high school physics 1 & 2 course and those with non-completion of them. The approach of changing major curriculum with consideration of learners' needs was recommended because the number of students with completion of the high school physics course would probably be decreasing rapidly under these circumstances such as the application of new national curriculum, the reduction of the number of the elective courses in Korea Scholastic Aptitude Test and so on.

• Journal of The Korean Association For Science Education
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• v.18 no.2
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• pp.245-256
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• 1998

In this study, we discussed about the implications of the idealization, which take an important role in physics, to the physics education. First, understanding of the idealization help the physics learning itself. This is because that various types of idealizations are included in the physics terms and concepts, derivation processes of physics laws and formulas, and explanation of natural phenomena and problem solving activities. Second, understanding of the idealization can help the application of the physics world to the real world. That is, by understanding the extent and the limit of idealization used in physics world, physics students can understand the discrepancies between the real world and the physics world. And also, by modifying or eliminating the idealization, students can extend the extent of understanding about how predictions based on the idealization used in the physics world will change. To do this, we suggested the application of computer simulation program in physics laboratories. Third, idealization take an important role in the inquiry learning for students' originality. The activities of identifying or controlling the variables, as one of the principal factors of scientific inquiry, need the appropriate establishment of the ideal conditions. And to analyze the limiting case or practice the thought experiments for understanding the impossible situation in the real world, ideal conditions also are needed. This study discussed above three aspects with various concrete examples and, with Park et al.'s study (Park et al., 1998), present the theoretical basis for the study of students' and teachers' understanding the idealization.

• Journal of information and communication convergence engineering
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• v.20 no.4
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• pp.242-249
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• 2022

Classical cryptography with complex computations has recently been utilized in the latest computing systems to create secret keys. However, systems can be breached by fast-measuring methods of the secret key; this approach does not offer adequate protection when depending on the computational complexity alone. The laws of physics for communication purposes are used in quantum computing, enabling new computing concepts to be introduced, particularly in cryptography and key distribution. This paper proposes a quantum computing lattice (CQL) mechanism that applies the BB84 protocol to generate a quantum key. The generated key and a one-time pad encryption method are used to encrypt the message. Then Babai's algorithm is applied to the ciphertext to find the closet vector problem within the lattice. As a result, quantum computing concepts are used with classical encryption methods to find the closet vector problem in a lattice, providing strength encryption to generate the key. The proposed approach is demonstrated a high calculation speed when using quantum computing.

• Journal of The Korean Association For Science Education
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• v.25 no.5
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• pp.603-609
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• 2005

Students obtain most concepts through textbooks, and teaching-learning activities between teachers and students. Accordingly, if science teachers already have misconceptions they will inevitably affect students' scientific concept. This study found many problems in teachers' cognition on the concepts of nuclear radiation. Because 12th grade physics II is classified as an optional subject in the 7th curriculum, teachers have few chances to teach it and, more importantly, have difficulty in teaching it because of the need to prepare students for the university entrance examination. The concept of radiation must be taught correctly because of its emergence in the 'environment' unit of 10th grade Science. Finally, results from this study can help science teachers teach these difficult concepts more correctly. In addition, results can also be useful in in-service retraining programs.

• Structural Engineering and Mechanics
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• v.55 no.1
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• pp.93-109
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• 2015

Finite element analysis (FEA) combined with the concepts of linear elastic fracture mechanics (LEFM) provides a practical and convenient means to study the fracture and crack growth of materials. In this paper, a numerical modeling of crack propagation in the cement mantle of the reconstructed acetabulum is presented. This work is based on the implementation of the displacement extrapolation method (DEM) and the strain energy density (SED) theory in a finite element code. At each crack increment length, the kinking angle is evaluated as a function of stress intensity factors (SIFs). In this paper, we analyzed the mechanical behavior of cracks initiated in the cement mantle by evaluating the SIFs. The effect of the defect on the crack propagation path was highlighted.

• Structural Engineering and Mechanics
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• v.42 no.6
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• pp.783-797
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• 2012

A new hybrid meta-heuristic optimization algorithm is presented for design of structures. The algorithm is based on the concepts of the charged system search (CSS) and the particle swarm optimization (PSO) algorithms. The CSS is inspired by the Coulomb and Gauss's laws of electrostatics in physics, the governing laws of motion from the Newtonian mechanics, and the PSO is based on the swarm intelligence and utilizes the information of the best fitness historically achieved by the particles (local best) and by the best among all the particles (global best). In the new hybrid algorithm, each agent is affected by local and global best positions stored in the charged memory considering the governing laws of electrical physics. Three different types of structures are optimized as the numerical examples with the new algorithm. Comparison of the results of the hybrid algorithm with those of other meta-heuristic algorithms proves the robustness of the new algorithm.

• Journal of the Korean Magnetics Society
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• v.5 no.5
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• pp.376-379
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• 1995

Employing the muffin-tin-orbital theory combined with pseudo-potential concepts, we have evaluated hybridization matrix elements between R and T sites in $RT_{2}$ compounds. The matrix elements are calculated with two parameters, the interatomic distance between R and T atoms from the crystal structure data, and the expectation values of the radial distances for the radial wave functions of the ground state charge densities, which are obtained from the linearized muffin-tin orbital band method within the local density approximation. It is found that the R 4f/T 3d hybridization matrix elements decrease with an increasing atomic number from R=Ce to Gd, and that they are smaller in $RNi_{2}$ than in $RCo_{2}$, which are consistent with trends observed in recent photoemission spectroscopy experiments. It is also found that the magnitudes of the hybridization matrix elements in $RFe_{2}$ are comparable to those in $RNi_{2}$.

• Nonlinear Functional Analysis and Applications
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• v.26 no.1
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• pp.117-135
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• 2021

Our purpose in this paper is to introduce the concept of complex valued convex metric spaces and introduce an analogue of the Picard-Ishikawa hybrid iterative scheme, recently proposed by Okeke [24] in this new setting. We approximate (common) fixed points of certain contractive conditions through these two new concepts and obtain several corollaries. We prove that the Picard-Ishikawa hybrid iterative scheme [24] converges faster than all of Mann, Ishikawa and Noor [23] iterative schemes in complex valued convex metric spaces. Also, we give some numerical examples to validate our results.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.28 no.1
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• pp.33-58
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• 2024

This paper reviews basic concepts for Physics-Informed Neural Networks (PINN) applied to the initial value problems for ordinary differential equations. In particular, using only basic calculus, we derive the error estimates where the error functions (the differences between the true solution and the approximations expressed by neural networks) are dominated by training loss functions. Numerical experiments are conducted to validate our error estimates, visualizing the relationship between the error and the training loss for various first-order differential equations and a second-order linear equation.