• Journal of the Korean Physical Society
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• v.73 no.9
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• pp.1230-1239
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• 2018

We derive a factorization theorem for the jet mass distribution with a given $p^J_T$ for the inclusive production, where $p^J_T$ is a large jet transverse momentum. Considering the small jet radius limit ($R{\ll}1$), we factorize the scattering cross section into a partonic cross section, the fragmentation function to a jet, and the jet mass distribution function. The decoupled jet mass distributions for quark and gluon jets are well-normalized and scale invariant, and they can be extracted from the ratio of two scattering cross sections such as $d{\sigma}/(dp^J_TdM^2_J)$ and $d{\sigma}/dp^J_T $. When $M_J{\sim}p^J_TR$, the perturbative series expansion for the jet mass distributions works well. As the jet mass becomes small, large logarithms of $M_J/(p^J_TR)$ appear, and they can be systematically resummed through a more refined factorization theorem for the jet mass distribution.

• Journal of IKEEE
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• v.11 no.4
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• pp.193-197
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• 2007

We use a saturation function with memory instead of a pure saturation function to generate a limit cycle in order to find one point information of a plant in the frequency domain. The saturation function with memory is useful in the presence of noise and/or a short duration of short duration of external disturbances. We analyze the error caused by the approximation that the saturation function with memory treated as a pure saturation function. We propose a new tuning formula for PID controller which can be applied a saturation function having memory with an arbitrary memory size. We show that the proposed method is more accurate than that of the approximation method via an example.

• Journal of the Korean School Mathematics Society
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• v.17 no.4
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• pp.697-716
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• 2014

The purpose of this paper is to investigate high school students' learning characteristics which revealed in their learning process of limit using GeoGebra. And we are going to analyze effects of teaching of limit using GeoGebra to high school students' interesting and attitudes for mathematics learning. To do this, we selected three high school students as participants and ask them performing limit learning using GeoGebra. We recorded their problem solving process. Through analyzing their problem solving process relate to their solution, we found the followings: First, students did not logically approach based on mathematical properties or given materials, rather showing tendency decide with self-conscious and intuition. Second, it is possible that former reasoning strategies disturb following reasoning in the process of high school students' mathematics learning. Third, learning process of limit using GeoGebra help high school students to identify and correct their errors relate to limit learning. Forth, learning process of limit using GeoGebra positively effects to high school students' interesting and attitudes for mathematics learning.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.708-710
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• 2004

This paper studies a multirate sampled-data control for LTI systems by using the digital redesign (DR) method. In this note, to well tackle the problem associated with both the state matching and the stabilization, our nobel strategy is to minimize the linear quadratic cost function. The main features of the proposed method are that i) the delta-operator-based descretization method is applied to improve the state-matching performance in the fast sampling limit and/or the large input multiplicity; ii) the proposed multirate control scheme can improve the state-matching performance in the long sampling limit; iii) some sufficient conditions that guarantee the stability of the closed-loop discrete-time system and provide a guarantee cost for the cost function can be formulated in the LMIs format; and iv) an optimal sampled-data controller in the sense of minimizing the upper bound of the cost function is also given by means of an LMI optimization procedure.

• East Asian mathematical journal
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• v.35 no.2
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• pp.239-257
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• 2019

The purpose of this study is to show that the topology is closely related to some subjects learned in school mathematics and then to give motivations for learning of the topology. To do this, it is showed that the topology is an abstracted device that deal with structure of limit and continuity introduced in school mathematics. This study took a literature study. The results of this study are as follows. First, the formal definition of general topology to structure open sets was examined. The nearness relation together with the closure operation was introduced and used to characterize for construction of general topology. Second, as definitions for continuity of function, we considered the intuitive definition, definition, structured definitions using open intervals and definition using open sets and then we investigated their roles. We also examined equivalent definition using the nearness relation which is helpful to understand continuity of function. Third, the sequence and its limit are treated in terms of continuous functions having the set of natural numbers and its extended set as domains. From these, it can be concluded that the convergence of sequence and the continuity of function are identified as functions that preserve the nearness relation and that the topology is a specialized tool for dealing with convergence and continuity.

• Journal of the Korean Geotechnical Society
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• v.23 no.8
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• pp.117-127
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• 2007

Slope stability analysis is a geotechnical engineering problem characterized by many sources of uncertainty. Some of them are connected to the uncertainties of soil properties involved in the analysis. In this paper, a numerical procedure for integrating commercial finite difference method into probabilistic analysis of slope stability is presented. Since the limit-state function cannot be expressed in an explicit form, the ANN-based response surface method is adopted to approximate the limit-state function and the first-, second-order reliability method and the Monte Carlo simulation technique are used to calculate the probability of failure. Probabilistic stability assessments for a hypothetical two-layer slope and the Sugar Creek embankment were performed to verify the application potential to the slope stability problems. The examples show the successful implementation and the possibility of the extension of the proposed procedure to the variety of geotechnical engineering problems.

• Journal of dental hygiene science
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• v.23 no.2
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• pp.154-168
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• 2023

Background: Legal regulations and fees have been established in Korea to provide visiting oral health care services to individuals with long-term care insurance (LTCI). However, beneficiaries of this service are very limited. Therefore, to improve the Korean system we propose a comparative analysis with the Japanese system. Methods: This study is a descriptive analysis based on secondary data, such as statistics, laws, and service record forms from Korea and Japan. The most recent institutional documents were obtained through a Google search. The variables investigated were financial resources of LTCI, co-payment structure, monthly limit of LTCI benefits, care levels of LTCI, service providers, service costs, contents of service, and the number of cases of service. Results: In both Korea and Japan, LTCI is financed through a combination of taxes and insurance premiums. However, the monthly limit for receiving LTCI services in Japan is about 2.4 times higher than in Korea. Visiting medical and dental treatment is also possible in Japan. Furthermore, nursing staff can provide daily oral health care services according to dental hygienists' instruction unlike Korea. Oral health care services in Korea are focused on oral hygiene and prevention of oral diseases, while Japan additionally provides oral function screening, patient education for oral health management, and training for nursing staff to enhance oral function, eating, and swallowing of the patients. Conclusion: We concluded that the possibility of visiting dental treatment, differences in monthly limit of LTCI benefits, oral function assessment and guidance, as well as collaboration with other healthcare professionals contributed to the difference in the frequency of utilization of visiting oral health care services between Korea and Japan.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.43 no.5
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• pp.693-702
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• 1994

This paper deals with direct voltage stability analysis using a power system energy function. The structure preserved energy function is proposed as an energy function for voltage stability analysis. With the use of the proposed energy function voltage collapse conditions are derived, which yields the exactly same results with the Jacobian matrix approach. The voltage collapse phenomenon is analyzed by several methods, which shows that all of the methods produce the same voltage condition. This study also investigates the voltage collapse dynamics by using the proposed energy function. As a result, it has been found that the voltage collapse can be classified into two categories: static and dynamic instablilties which have quite different behaviors. In addition a new method is presented to calculate the power capacity limit of transmission lines with respect to voltage stability. The proposed method is tested for a 2-bus sample system, which shows the characteristics of voltage collapse phenomenon via the energy function.

• Journal of the Korean School Mathematics Society
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• v.26 no.2
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• pp.87-110
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• 2023

This study aimed to proposed repeated reading aloud, which combines repetitive reading and reading aloud, as a method for teaching and learning mathematics. We investigated the effect of repeated reading aloud on students' academic achievement and cognitive load, and explored the implications of repeated reading aloud as a method for teaching and learning mathematics. To this end, we conducted a case study involving repeated reading aloud for two units: the limit of a function and the number of cases. The study targeted four 9th-grade students and four 10th-grade students, analyzing how their academic achievement and cognitive load changed. As a result, the eight students showed positive changes in academic achievement and cognitive load as the repeated reading aloud accumulated. When comparing the units, the academic achievement was lower for the limit of function than the number of cases. In terms of cognitive load, students exhibited higher cognitive load in the unit on the limit of function. When compared cognitive load by grade, there was no significant difference after 3rd repeated reading. However, in both units, the academic achievement of four 10th-grade students was higher than that of four 9th-grade students. Nonetheless, the gap narrowed as the reading aloud was repeated.

• Journal of Mechanical Science and Technology
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• v.14 no.1
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• pp.39-47
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• 2000

Bifurcation intability modes of axially compressed circular cylindrical shell are investigated in the limit of zero thickness (i.e., h (thickness) ${\rightarrow}$ 0) analytically, adopting the general stability theory developed by Triantafyllidis and Kwon (1987) and Kwon (1992). The primary state of the shell is obtained in a closed form using the asymptotic technique, and then the straight-forward bifurcation analysis is followed according to the general stability theory to obtain the bifurcation modes in the limit of zero thickness in a full analytical manner. Hence, the closed form bifurcation solution is obtained. Finally, the result is compared with the classical one.