• 한국수학교육학회지시리즈A:수학교육
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• 제24권2호
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• pp.27-34
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• 1986

At present, Japanese textbooks of mathematics for elementary and secondary schools are thorized by the Ministry of Education. In former days, this system was also in effect for mentary schools until 1905 and for secondary schools until 1944. this article we discuss the start and the change of this system until 1905 and its influences the textbooks of mathematics. The main interest of the system was originally to prevent the textbooks from having the pressions which have the fear of breaking laws, disturbing the public morals or mistaking real facts. The interest changed to assure that the textbooks might comply with the ional standards of teaching syllabuses. And the standards such as the ones of the sizes of ers in the textbooks were made public one after another. The comments attached to the textbooks which applied for the authorization often pointed out use of unsuitable concrete numbers. The comments were often concerned with the difficulty words or sentenses for elementary schools and with the incorrectness of mathematical contents secondary schools. We conclude that the system encouraged the rapid modernization and regularization of Japanese tbooks during this period. We may note that there was a tendency not to adopt an extremely usual trial into the textbooks.

• Agricultural and Biosystems Engineering
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• 제4권1호
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• pp.34-38
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• 2003

A mathematical model was developed for estimating the mechanical interrelation between characteristics of soil and main design factors of a tracked vehicle, and predicting the tractive performance of the tracked vehicle. Based on the mathematical model, a computer simulation program (TPPMTV) was developed in the study. The model considered the continuous change in tension for the whole track of a tracked vehicle, the analysis of shape and tension of the track segment between sprocket and first roadwheel, and the side thrust on both sides of grouser by the active earth pressure theory in predicting the tractive performance of a tracked vehicle. Also, the model contained not only sinkage depth of the track but the pressure distribution under the track in analyzing the side thrust. The effectiveness of the developed model was verified by performing the draw bar pull tests with a tracked vehicle reconstructed for test in loam soil with moisture content of 18.92％. The predicted drawbar pulls by the model were well matched to the measured ones. Such results implied that the model developed in the study could estimate the drawbar pulls well at various soil conditions, and would be very useful as a simulation tool for designing a tracked vehicle and predicting its tractive performance.

• 한국수학교육학회지시리즈A:수학교육
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• 제55권3호
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• pp.251-279
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• 2016

There are many studies on 'how' students solve mathematical problems, but few of them sufficiently explained 'why' they have to solve the problems in their own different ways. As quantitative reasoning is the basis for algebraic reasoning, to scrutinize a student's way of dealing with quantities in a problem situation is critical for understanding why the student has to solve it in such a way. From our teaching experiments with two ninth-grade students, we found that emergences of a certain level of covariational reasoning were highly consistent across different types of problems within each participating student. They conceived the given problem situations at different levels of covariation and constructed their own quantity-structures. It led them to solve the problems with the resources accessible to their structures only, and never reconciled with the other's solving strategies even after having reflection and discussion on their solutions. It indicates that their own structure of quantities constrained the whole process of problem solving and they could not discard the structures. Based on the results, we argue that teachers, in order to provide practical supports for students' problem solving, need to focus on the students' way of covariational reasoning of problem situations.

• 한국수학교육학회지시리즈A:수학교육
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• 제54권3호
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• pp.283-298
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• 2015

This research is the case study of collaborative mentoring in the professional development of multi-tiered mathematics teacher community. We observed the procedures of mentoring, and contents of mentoring in PD program. For this purpose, we implemented PD program with participant unit composed of 3 or 4 teachers in the same school and total 25 teachers from 4 elementary schools and 4 high schools. Also there were 1 mentor and 1 sub-mentor to support each school. Observed mentoring processes were all recorded and the participants not only were interviewed several times but also wrote reflection notes after meetings. While mentoring PD program was implemented, mentor and mentee had joint responsibility about lessons implemented by mentee. Furthermore It showed possibility of change of teacher learning culture, learning culture of community. It means that teacher would improve their professionalism more effectively within teacher community instead of individual. 4 reflection contents was founded in collaborative mentring; 1)purpose of mathematics education, 2)motivation and connection between previous lecture and present lecture 3)lack of mathematical contents in lesson 4)discourse between teacher and students.

• 한국수학교육학회지시리즈C:초등수학교육
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• 제10권2호
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• pp.77-110
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• 2007

This study attempted to investigate how to students show high-level mathematical thinking in math classes. This paper describes how to setup the task for lead to a high - level of thinking out students and what efforts are required while a teacher tried to maintaining students's high-level cognition during the tasks implemented. The researcher as teacher analyzed the tasks of length measurement unit in 2-Ga elementary math textbooks, modified and created math tasks demanded students' high-level cognition, made instruction plans, and implemented those tasks maintaining the levels of cognitive demand of tasks. After that, the researcher reflected and analyzed the levels of cognitive demand of tasks of instruction and factors that cause to change intended high-level cognitive demand. After reflection, second roof of action research was conducted to 2-Na length measurement unit. This paper includes those results and reflections of practitioner.

• 대한전기학회논문지:시스템및제어부문D
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• 제50권10호
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• pp.494-501
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• 2001

In this study, the effects of vascular parameter changes and electrodes on VOP measurement based on IPG were simulated mathematically. For the evaluation of the effects of hemodynamic changes on VOP, a mathematical model, which consists of cardiovascular system model and venous occlusion model, was developed and the model solution representing the blood flow and pressure in measuring point was found by 2nd order Runge-Kutta method. And, with sensitivity coefficients obtained from finite element solution of electric field in measuring point, the effects of electrode system on measurement were evaluated. As increasing the resistance, the venous capacitance was not changed but the venous outflows were decreased and the decreased compliance reduced the venous capacitance. And, for several configurations of round electrodes and band electrodes, the sensitivity coefficients were computed using the electric field distribution along deep vein. In conclusion, the proposed mathematical cardiovascular model could be applied to the simulation study on the effects of hemodynamic parameters on DVT diagnosis with IPG. And, also the sensitivity coefficients could provide effective electrode configuration for exact measurement of VOP.

• 조명전기설비학회논문지
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• 제29권11호
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• pp.89-95
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• 2015

As a solution of improving the energy efficiency in power system, Low Voltage DC (LVDC) distribution systems different from conventional ones have been constantly researched. As in conventional AC distribution system, LVDC distribution system can suffer from High Impedance Fault (HIF) which may cause a failure of protective relay due to relatively low change in magnitude of fault current. In order to solve the problem, a scheme for detecting HIFs is presented in this paper. Closing Opening Difference Operation (CODO) based on Mathematical Morphology (MM), one of the MM-based filters, is utilized to make fault signals discriminable. To verify performance of the scheme, a simple LVDC distribution system is modeled by using ElectroMagnetic Transient Program (EMTP) software. Computer simulations according to various conditions are performed and comparison studies with a scheme using Wavelet Transform (WT) in an aspect of simulation time are also conducted.

• International Journal of Computer Science & Network Security
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• 제21권1호
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• pp.49-54
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• 2021

Relative to the outer surface of the mastic coating, the reliability of the available waterproofing resource is determined by the ability to stabilize the structural characteristics in difficult climatic conditions. Organic components of mastic as a result of solar radiation, elevated temperatures and their alternating change, atmospheric oxidants, especially in industrial areas, have a tendency to self-polymerization and loss of low molecular weight components. This is the gradual loss of deformability and the transition to brittleness with its tendency to crack as the reasons for the gradual transition from normal to emergency operating condition.The presented mechanism of functioning of the coating surface indicates the expediency of increasing its components, able to stabilize the structure and prevent changes in deformability.Durability, hydrophobicity, water displacement, water absorption are accepted as estimating indicators. The main dependences of the influence of the lost additional components of mastic on the operational properties of the formed coating characterize the ability to provide successful resistance to environmental influences and longer stability. As a result, mastic acquires additional service life.

• 정보처리학회논문지B
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• 제9B권3호
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• pp.293-302
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• 2002

내용기반 검색을 위한 비디오 데이터 장면전환 검출에서 점진적인 전환을 검출하는 것은 갑작스런 전환을 검출하는 것에 비해 일반적으로 어려운 문제로 알려져 있다. 본 논문에서는 가변형 동적 임계값과 가장 최근에 검출된 컷 프레임과 현재 프레임간의 특징값 차이인 컷 프레임 차를 이용하여 갑작스런 전환과 점진적인 전환을 찾아내는 기법을 제안한다. 이를 위하여 본 논문에서는 점진적인 전환이 갖는 특성과 수학적 모델을 제시하고 컷 프레임 차를 이용하여 점진적인 전환을 검출할 수 있음을 보인다. 그리고 이를 바탕으로 갑작스런 전환과 점진적인 전환을 함께 검출할 수 있는 방법을 제시한다. 실세계 동영상 데이터를 대상으로 한 실험을 통해 제안하는 기법이 점진적인 전환 효과의 종류에 종속적이지 않으며 적은 연산 비용으로 쉽게 점진적인 전환 유무를 검출 할 수 있음을 보인다.

• 한국수학교육학회지시리즈A:수학교육
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• 제61권3호
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• pp.419-439
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• 2022

본 연구의 목적은 프로이덴탈의 수학화 과정과 일차함수 개념의 교수학적 현상학의 분석을 통하여 학생들이 변화율이 일정한 현상을 표, 그래프, 식으로 표현하는 과정과 일차함수 개념의 심상을 구성하는 과정, 본질을 구성하는 과정을 서술하고 분석하는 것이다. 연구 결과, 학생들은 변화율이 일정한 현상을 표로 표현할 때 합성단위로서의 비를 사용하고, 그래프로 표현할 때 한 학생을 제외하고 직선으로 표현하였다. 식으로 표현할 때 학생별로 주어진 상황, 공변 관점, 대응 규칙을 이용하는 수준의 차이가 있었다. 학생들은 두 변화량 사이의 관계를 곱셈적으로 비교하였고, 그 비율이 하나의 상수가 된다는 것을 교사의 안내에 따라 구성하였다. 특히 시간의 변화량과 거리의 변화량이 하나의 값, 속력이 되는 상황을 통하여 변화율이 일정하다는 심상을 구성하였다. 단, 변화율을 직선의 기울기와 연결하는 데에는 어려움을 겪었으나, 변화율이 일정하다는 심상과 그래프가 직선이며 식의 모양이 y=ax+b (a는 변화율, b는 절편)라는 심상을 정리하고 조직하여 일차함수의 본질(개념)을 구성하였다.