• East Asian mathematical journal
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• v.27 no.2
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• pp.141-161
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• 2011

This research is a laboratory study for the improvement of differential equation class, and the aim of this study is to propose the possibilities of applicable writing activities for differential equation courses in university. We analyzed how the writing activities can affect the improvement of abilities of the students' affective domain and cognitive domain. Although the results from the two areas did not show a big numerical improvements it proved that the writing activities have positive effects, especially for the group of lower level students. The students felt interested and became more confident with differential equation studies. Their understanding of the study has been increased further by acquiring new learning methods, including writing activities. Therefore, we conclude that teaching and learning method designed systematically to adopt writing activities improve the students' learning attitudes and achievements.

• The Mathematical Education
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• v.60 no.3
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• pp.297-319
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• 2021

The present study explored a relationship between mathematical understandings of teachers and ways in which their knowledge transferred in designing lessons for hypothetical students from Gess-Newsome (1999)'s transformative perspective of pedagogical content knowledge. To this end, we conducted clinical interviews with four secondary mathematics teachers of their solving and teaching of equation writing. After analyzing the teacher participants' attention to Key Developmental Understandings (Simon, 2007) in solving equation writing, we sought to understand the relationship between their mathematical knowledge of the problems and mathematical knowledge in teaching the problems to hypothetical students. Two of the four teachers who attended the key developmental understandings solved the problems more successfully than those who did not. The other two teachers had trouble representing and explaining the problems, which involved reasoning with improper fractions or reciprocal relationships between quantities. The key developmental understandings of all four teachers were reflected in their pedagogical actions for teaching the equation writing problems. The findings contribute to teacher education by providing empirical data on the relationship between teachers' mathematical knowledge and their knowledge for teaching particular mathematics.

• Journal of Magnetics
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• v.19 no.3
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• pp.237-240
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• 2014

For heat-assisted magnetic recording, magnetization reversal probabilities of nano-Pt/MnSb multilayer film with perpendicular magnetic anisotropy under thermal pulse activation were investigated numerically by solving the Landau-Lifshift Gilbert Equation. Magnetic parameters of nano-Pt/MnSb multilayer were used with anisotropy energy of $3{\times}10^5$ erg/cc and saturation magnetization of 2100 G, which offer more than 10 y data stability at room temperature. Scheme of driven magnetic field and thermal pulse on writing mechanism was designed closely to real experiment. This study found that the chosen material is potential to be used as a high density magnetic storage that requires low writing field less than two-hundreds Oersted through definite heating and cooling interval. The possibility of writing data with a zero driven magnetic field also became an important result. Further study is recommended on the thickness of media and thermal pulse design as the essential parameters of the reversal magnetization.

• Journal of the Korean Chemical Society
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• v.59 no.6
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• pp.499-507
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• 2015

The purpose of this study is to investigate middle school students’ understanding of ionic equation. Two hundreds and nineteen middle school students were participated in the study. After six class hours of learning ‘electrolyte and ion’ unit, instrument was implemented to evaluate students’ understanding of ionic process and ability to write ionic equation. We analyzed the influence of characteristics of ionic compounds on correct answer rate. In addition, knowledge state of students required for writing ionic equation was analyzed. The results were as follows: First, ionic compounds tested were categorized into six groups. The correct answer rate was different depending on the characteristics of each group. Second, knowledge state required for writing ionic equation was structured. Based on results some suggestion were made to develope effective learning strategy for understanding ionic equation.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.4
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• pp.575-584
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• 2017

It is suggested the circuit network to analyze the time response of control system. And it is analyzed the interrelation for classical control and modern control by the transfer function and the state equation. Without complicated integration of state transition equation, it is suggested to possible time response by combining the state transition matrix and the transfer function. A source program is coded to display the time response according to the unit-step and the sinusoidal input. Transient response is analyzed in the unit-step input and phase difference between current and voltage is analyzed in sinusoidal input. As writing the suggested contents in transient response or state-space analysis, it is improved the understanding for control engineering and ability for system design.

• Journal of the Korean Institute of Telematics and Electronics
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• v.13 no.4
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• pp.18-23
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• 1976

We have obtained the solution of van der Pol's equation characterized by an arctangent nonlinearity, using the perturbation method by writing periodicity conditions: $$X^{(n)}(2{\pi})-X^{(n)}(0)=0$$ $$X^{(n)'}(2{\pi})-X^{(n)'}(0)=0 (n=0,1,2......)$$ together with the starting condition: $$X^{(n)}(\frac{\pi}{2})=0,\;X^{(n)}'(\frac{\pi}{2})=-R^{(n)}$$. Our results agree with Liapunov's theorem and our calculated value is more similar to Murata's measured value than Murata's calculated value.

• Journal of the Korean School Mathematics Society
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• v.23 no.1
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• pp.25-44
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• 2020

This study investigated the representation and algorithms of western mathematics reflected on the algebra domains of Chosun-Sanhak in the 18th century. I also analyzed the co-occurrences and replacement phenomenon between western algorithms and traditional algorithms. For this purpose, I analyzed nine Chosun mathematics books in the 18th century, including Gusuryak and Gosasibijip. The results of this study are as follows. First, I identified the process of changing to a calculation by writing of western mathematics, from traditional four arithmetical operations using Sandae and the formalized explanation for the proportional concept and proportional expression. Second, I observed the gradual formalization of mathematical representation of the solution for a simultaneous linear equation. Lastly, I identified the change of the solution for square root from traditional Gaebangsul and Jeungseunggaebangbeop to a calculation by the writing of western mathematics.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.280-283
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• 2003

In this paper, there was finding laser beam focal length using the camera at the work with laser preprocess. A process have some similarity that the laser direct writing was condition of unused other light source in order to a partical object of working substrate, so we worked finding focal length using yellow light. As we found focal lengths from three points of substrate edges, The focal length of all substrates was able to be computed by calculating a plane equation using these three point. Also we make a device and software that can automatically perform all of the processes.

• Advances in concrete construction
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• v.13 no.6
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• pp.451-459
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• 2022

In present study, the nonlocal Flügge shell model based is utilized to investigate the vibration characteristics of armchair and chiral single-walled carbon nanotubes with impact of small-scale effect subjected to two boundary supports. The wave propagation approach is employed to determine eigen frequencies for armchair and chiral tubes. The fundamental frequencies scrutinized with assorted aspect ratios by varying the bending rigidity. The raised in value of nonlocal parameter reduces the corresponding fundamental frequency. It is investigated with higher aspect ratio, the boundary conditions have a momentous influence on vibration of CNT. It is concluded that frequencies would increase by increasing of the bending rigidity. Solutions of the frequency equation have determined by writing in MATLAB coding.

• Korean Journal of Child Studies
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• v.24 no.1
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• pp.99-108
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• 2003

This study was based on theories of the culture of poverty and the causes and consequences of poverty. The strong relationship of family income to mother's education presents the possibility of an intergenerational education cycle. Using a longitudinal approach, parental poverty status was measured by family income, welfare assistance, single parent, and occupation when children were 2 years of age; children's school performance was measured by teacher reports of their reading, mathematics, writing, and overall ability at grade 1. Data were analyzed by structure equation modeling. Results showed that mother's pre-childbearing level of education predicted child school performance in grade 1, confirming an intergenerational cycle. In addition, the results indicated that parental poverty acts as a mediator between the cycle.