• 한국수학교육학회지시리즈A:수학교육
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• 제42권1호
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• pp.41-56
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• 2003

As the information society appears, the increasing power and access of personal computers along with wide spread use of the information technology has not only changed the landscape for communication but it has opened up new and exciting opportunities for education. One of the ways that information technology could help improve education is to be used in interactive communication to share the knowledge and experience of all the teachers as well as students. In this paper, the use and application of information communication technology[ICT] into mathematics classroom are described and showed several examples. furthermore, the web site design and developed for this study was introduced of the purpose of sharing the ideas about the knowledge and usage of the history of mathematics and examples of mathematical connections. The study suggests that enabling mathematics in incorporating of ICT by teachers and students requires more effort to be made in training teachers on the use and application of ICT into mathematics classroom.

• 한국수학교육학회지시리즈D:수학교육연구
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• 제4권2호
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• pp.63-77
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• 2000

The purpose of this article is to devise the activities based on van Hiele levels of geometric thought using computer software, Geometer\\\\`s Sketchpad(GSP) as a tool. The most challenging task facing teachers of geometry is the development of student facility for understanding geometric concepts and properties. The National Council of teachers of Mathematics(Curriculum and Evaluation Standards for School Mathematics, 1991; Principles and Standards for School Mathematics, 2000) and the National Re-search Council(Hill, Griffiths, Bucy, et al., Everybody Counts, 1989) have supported the development of exploring and conjecturing ability for helping students to have mathematical power. The examples of the activities built is GSP for students ar designed to illustrate the ways in which van Hiele\\\\`s model can be implemented into classroom practice.

• 한국학교수학회논문집
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• 제10권1호
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• pp.45-69
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• 2007

21세기 지식 기반, 정보화 기반 사회는 수학을 단순히 적용하는 능력이 아닌 실생활이나 다른 교과 영역에서 수학적 지식을 사용하여 문제를 구성하고 해결하는 문제 해결력 등의 수학적 힘(Mathematical power)을 필요로 한다. 수학적 힘을 기르기 위해서는 수학의 기본 지식, 추론 능력, 문제 해결력, 수학적 아이디어의 표현 및 교환능력, 그리고 사고의 유연함, 인내, 흥미, 지적 호기심, 창의력을 길러 주는 다양한 교수 학습 방법이 필요하다. 본 연구에서는 다양한 학습 매체를 이용한 실생활 중심의 교수 학습 지도안을 개발하고 이를 통하여 학생들의 수업에 대한 반응과 수학에 대한 인식 변화를 분석하였다.

• Journal of Biosystems Engineering
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• 제12권2호
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• pp.1-15
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• 1987

A mathematical model is developed and computer programmed for simulation of power tiller motion. The model consists of a main body and two driving wheels resulting in an 8 degrees of freedom system. Drawbar loading is also included by coupling the model with a sub-model representing the implement to be used. The computer program SIMPTL can predict motion characteristics and static stability of power tiller under a given set of ground and operation conditions.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 D
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• pp.2082-2085
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• 2002

This paper describes the development of a gas turbine engine simulator in detail. The simulator presented in this paper has a mathematical engine model based on a target gas turbine engine performance data and is developed for generating a gas turbine engine sensor signals between the hardwares and softwares of a gas turbine engine control system using Data Acquisition systems(DAS) and 1553B communication, a aeronautic standard communication specification. In addition, this paper proves the excellent performance of this simulator by showing the results of a gas turbine engine field test and simulation.

• Journal of Mechanical Science and Technology
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• 제17권12호
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• pp.2087-2098
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• 2003

The development of numerical mathematical model to calculate both the static and dynamic characteristics of a multi-shaft gas turbine consisting of a single combustion chamber, including advanced cycle components such as intercooler and regenerator is presented in this paper. The numerical mathematical model is based on the simplified assumptions that quasi-static characteristic of turbo-machine and injector is used, total pressure loss and heat transfer relation for static calculation neglecting fuel transport time delay can be employed. The supercharger power has a cubical relation to its rotating velocity. The accuracy of each calculation is confirmed by monitoring mass and energy balances with comparative calculations for different time steps of integration. The features of the studied gas turbine scheme are the starting device with compressed air volumes and injector's supercharging the air directly ahead of the combustion chamber.

• 한국수학교육학회지시리즈D:수학교육연구
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• 제7권3호
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• pp.163-189
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• 2003

The purpose of this study is to develop a test, which can be used in creative problem solving ability in mathematics of the mathematically gifted and the regular students. This test tool is composed of three categories; fluency (number of responses), flexibility (number of different kinds of responses), and originality (degree of uniqueness of responses) which are the factors of the creativity. After applying to 462 middle school students, this test was analyzed into item analysis. As a results of item analysis, it turned out to be meaningful (reliability: 0.80, validity: item 1(1.05), item 2(1.10), item 3(0.85), item 4(0.90), item 5(1.08), item difficulty: item 1(-0.22), item 2(-0.41), item 3(0.23), item 4(0.40), item 5(-0.01), item discriminating power: item 1(0.73), item 2(0.73), item 3(0.67), item 4(0.51), item 5(0.56), over the level of a standard basis. This means that the test tool was useful in the test process of creative problem solving ability in mathematics

• Journal of Power Electronics
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• 제5권3호
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• pp.198-205
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• 2005

The mechanical system of a drive can often be modeled as a two- or three-mass-system. The load is coupled to the driving motor by a shaft able to perform torsion oscillations. For the automatic tuning of the control, it is necessary to know the mathematical description of the system and the corresponding parameters. As the manpower and setup-time necessary during the commissioning of electrical drives are major cost factors, the development of self-operating identification strategies is a task worth pursuing. This paper presents an identification method which can be utilized for the assisted commissioning of electrical drives. The shaft assembly can be approximated as a two-mass non-rigid mechanical system with four parameters that have to be identified. The mathematical background for an identification procedure is developed and some important implementation issues are addressed. In order to avoid the excitation of the system with its natural resonance frequency, the frequency response can be obtained by exciting the system with a Pseudo Random Binary Signal (PRBS) and using the cross correlation function (CCF) and the auto correlation function (ACF). The reference torque is used as stimulation and the response is the mechanical speed. To determine the parameters, especially in advanced control schemes, a numerical algorithm with excellent convergence characteristics has also been used that can be implemented together with the proposed measurement procedure in order to assist the drive commissioning or to achieve an automatic setting of the control parameters. Simulations and experiments validate the efficiency and reliability of the identification procedure.

• 호남수학학술지
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• 제43권4호
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• pp.717-739
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• 2021

We used blood data to predict obesity by complementing the BMI risk, because some blood factors are significantly associated with obesity. For the sampling method, a two-step stratified colony sampling method was used based on sixteen blood factors collected by the Korea National Health and Nutrition Examination Survey(KNHANES). We identify the number of effective blood data of obesity in the final model as 6 ~ 8 factors that differ somewhat depending on age and gender. Also, the coefficient of determination that represents the predictive power of obesity in the regression model is the highest for both men and women of aged 19 and in their 20s and 30s, and the predictive power decreases with increasing age.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 추계학술대회 논문집 학회본부
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• pp.623-625
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• 1997

This paper deals with the simulator for the diagnosis systems of high speed train. The purpose of this simulator is the verification of diagnosis systems. In this paper, the configuration of high speed train is investigated and the implementation model of power car is proposed. According to the model, mathematical equation is constructed. Dynamic simulation is executed and analyzed.