• 정보학연구
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• 제8권3호
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• pp.1-10
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• 2005

Cosine and Sine function is widely used for the arithmetic, translation, object drawing, Simulation and etc. of Computer Graphics in Natural Science and Engineering. In general, Cordic Algorithm is effective method since it has relatively small size and simple architecture on trigonometric function generation. However profitably it has those merits, the problem of operation speed is occurred. In graphic display system, the operation result of object drawing is quantized and has the condition that is satisfied with rms error less than 1. So in this paper, the proposed generator is composed of partition operation at each ${\pi}/4$ and basic Cosine, Sine function generator in the range of $0{\sim}{\pi}/4$ using the lower order of Tayler's series in an acceptable error range, that enlarge the range of $0{\sim}2{\pi}$ according to a definition of the trigonometric function for the purpose of having a high speed Cosine, Sine function generation. And, division operator using code partition for divisor three is proposed, the proposed function generator has high speed operation, but it has the problems in the other application parts with accurate results, is need to increase the speed of the multiplication.

• 대한안전경영과학회지
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• 제25권1호
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• pp.15-21
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• 2023

In modern society, the delivery service market has grown explosively due to rapid changes in social structure and the recent COVID-19 pandemic. Therefore, various problems such as injury to workers and an increase in human accidents are occurring due to the loading and unloading of parcels. In order to solve this problem, domestic company n is developing a "robot-based cargo loading and unloading system". In developing a new technology system, quantitative reliability targets should be set for efficient operation and development. In this paper, reliability analysis was conducted through field data for the pneumatic gripper of the "robot-based cargo loading system". The reliability of the failure data was analyzed to estimate the distribution parameters and MTTF. Random data was derived for the probability of occurrence of a failure with the estimated value. By repeating the simulation to predict the number and year of failures according to the estimated parameters of the probability distribution, it was proposed as a method that reflects realistic probabilities rather than calculating with simple arithmetic using the average MTTF previously used in the field.

• 정보교육학회논문지
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• 제13권3호
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• pp.325-339
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• 2009

ICT는 교육의 효과를 증대시킬 수 있는 강력한 도구라는 이유로 교육에서의 활용이 중시되어 왔다. 그 중 Excel은 뛰어난 수식 계산과 논리 판단 기능을 갖추고 있고 다양한 종류의 계산을 할 수 있다는 점에서 수학과에서 그 가능성이 제시되어 왔다. 그러나 기존의 연구는 대부분 중 고등학교 수학과 통계단원에 중점을 두어 이루어 졌다. 그러나 함수의 사용이나 영어로 된 명령어는 초등학교에서 활용하기에는 무리가 있었다. 이에 본 연구에서는 초등학교에서 Excel을 활용하여 수학문제를 해결하는데 있어 단순 계산보다는 문제해결을 위한 사고에 중점을 둔 문제해결수업모형을 개발하여 적용하고 결과를 알아보았다. 연구 결과 문제를 해결하는데 있어 엑셀을 이용하였을 때가 필기보다 문제를 해결하는 성공률이 더 높고, 문제해결 시간이 더 단축된 것을 알 수 있었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.244-246
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• 2001

In a full digital implementation of a current regulator, the voltage output is inevitably delayed due to arithmetic calculation and PWM. In case of the synchronous frame current regulator, the time delay is accompanied by the rotation of frame. In some applications in which the ratio of sampling frequency to output frequency is not high enough, such as high power drive or super high-speed drive, it is known that the effect of rotation of frame during the delay time causes phase and magnitude error in the voltage output. The error degrades the dynamic performance and can bring about the instability of current regulator at high speed. It is also intuitively known that advancing the phase of voltage output can mitigate the instability. In this paper, the instability problems are studied analytically and a compensation method for the error has been proposed. By means of computer simulation and complex root locus analysis, comparative study with conventional methods is carried out and the effectiveness of proposed method is verified.

• 한국지능시스템학회논문지
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• 제12권4호
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• pp.373-378
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• 2002

기존의 대부분의 퍼지 제어기는 퍼지 추론시 [0, 1]의 소속도를 갖는 퍼지 소속함수들의 실수연산으로 인하여 연산수행 속도가 저하되는 문제를 가지고 있다 따라서 본 논문에서는 실수연산으로 인하여 야기되었던 속도 저하문제를 해결하기 위한 새로운 퍼지연산 기법으로 실수 값을 갖는 퍼지 소속함수 값을 정수형 격자(pixel)에 매핑시켜 정수형 퍼지 소속 함수값만을 가지고 연산함으로써 기존의 퍼지제어기에 비해 매우 빠른 연산을 수행 할 수 있는 고속 퍼지제어기를 제안한다. 또한 퍼지 제어시스템 설계시에 퍼지 입출력 변수들의 퍼지항들을 입력시킬 수 있는 GUI(Graphic User Interface)를 제공하여 소속함수의 수정 및 퍼지 값 입력시 사용자에게 보다 편리한 환경을 제공한다

• Journal of Electrical Engineering and Technology
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• 제10권5호
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• pp.2062-2069
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• 2015

In the series hybrid active power filter (SHAPF) with magnetic flux compensation (MFC), the system current oscillate in the experimental results when adding the same phase harmonic current command in current control block. This condition endangers the security of the SHAPF. Taking the digit period average arithmetic as example, this paper explains the inter-harmonics current oscillation in the experiment. The conclusion is that the SHAPF is unstable to the inter-harmonics current in theory. Limited by the capacity of the inverter, the system current and the inverter output current do not increase to infinite. At last, some methods are proposed to solve this problem. From the practical viewpoint, the voltage feed-forward control is easy to achieve. It can suppress the current oscillation problems, and also improve the filtering effect. The feasibility of the methods is validated by both the emulation and experiment results.

• 한국수학교육학회지시리즈A:수학교육
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• 제57권2호
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• pp.93-110
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• 2018

One of the biggest changes in the 2015 revised mathematics curriculum is shifting to the second year of middle school in Pythagorean theorem. In this study, the following subjects were studied. First, Pythagoras theorem analyzed the expected problems caused by the shift to the second year middle school. Secondly, we have researched the reconstruction method to solve these problems. The results of this study are as follows. First, there are many different ways to deal with Pythagorean theorem in many countries around the world. In most countries, it was dealt with in 7th grade, but Japan was dealing with 9th grade, and the United States was dealing with 7th, 8th and 9th grade. Second, we derived meaningful implications for the curriculum of Korea from various cases of various countries. The first implication is that the Pythagorean theorem is a content element that can be learned anywhere in the 7th, 8th, and 9th grade. Second, there is one prerequisite before learning Pythagorean theorem, which is learning about the square root. Third, the square roots must be learned before learning Pythagorean theorem. Optimal positions are to be placed in the eighth grade 'rational and cyclic minority' unit. Third, Pythagorean theorem itself is important, but its use is more important. The achievement criteria for the use of Pythagorean theorem should not be erased. In the 9th grade 'Numbers and Calculations' unit, after learning arithmetic calculations including square roots, we propose to reconstruct the square root and the utilization subfields of Pythagorean theorem.

• 한국초등수학교육학회지
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• 제14권1호
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• pp.43-64
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• 2010

이 연구는 초등학교 3학년 학생의 수학 학습 능력 즉, 확고한 개념 형성 및 수학하는 힘의 신장과 창의력 육성을 목표로 하였다. 이러한 목표를 달성하기 위하여, 본 연구자는 2009년 1학기 동안 초등학교 3학년을 대상으로 [교과서의 내용 학습]$\rightarrow$[1차 문제 만들기]$\rightarrow$[문제 해결]$\rightarrow$[발전 문제 만들기]의 수업 모형으로, 연속 2시간의 연차시 수학 수업을 16회 실시하였다. 그 중에서 사칙계산을 중심으로 한 8회분의 학생이 만든 문제, 즉 [1차 문제 만들기]와 [발전 문제 만들기]를, 문제의 완성도 및 유창성, 유연성, 개념의 정도, 독창성, 소재 등의 5가지 요소로 분석틀을 만들어 분석하였다. 학생들은 1차 문제 만들기에서 문제의 완성도와 유창성은 더 나았고, 나눗셈과 곱셈으로 수업을 지속할수록 유연성은 점차 좋아졌다. 비교반을 설정하여 1학기 초와 말의 학업 성취도의 정도를 실험반과 비교한 결과 실험반의 학업성취도가 비교반 보다 높게 나타났다.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2006년도 International Symposium on GPS/GNSS Vol.1
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• pp.229-234
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• 2006

There are still some key problems having to be solved in theory and technique applications when GPS is used to monitor the vertical deformation of ground with high precision. Utilizing the GPS technology to monitor the deformation of the land subsidence and ground fissure in Xi'an, this paper puts forward advice that the datum frame of GPS network has significant influence on the precision and accuracy of the vertical deformation results by some research. The co-authors make some theoretical study of the datum error and practice by establishing the datum error models, especially the influence of scale and azimuth datum errors on GPS monitoring network. Then the datum frame design methods and arithmetic of GPS monitoring network are presented and have taken a good effect.

• Structural Engineering and Mechanics
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• 제51권5호
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• pp.793-808
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• 2014

The goal of this study is to evaluate and design steel plates with optimal material distributions achieved through a specific material topology optimization by using a CCARAT (Computer Aided Research Analysis Tool) as an optimizer, topologically optimally updating node densities as design variables. In typical material topology optimization, optimal topology and layouts are described by distributing element densities (from almost 0 to 1), which are arithmetic means of node densities. The average element densities are employed as material properties of each element in finite element analysis. CCARAT may deal with material topology optimization to address the mean compliance problem of structural mechanical problems. This consists of three computational steps: finite element analysis, sensitivity analysis, and optimality criteria optimizer updating node densities. The present node density based design via CCARAT using node densities as design variables removes jagged optimal layouts and checkerboard patterns, which are disadvantages of classical material topology optimization using element densities as design variables. Numerical applications that topologically optimize reinforcement material distribution of steel plates of a cantilever type are studied to verify the numerical superiority of the present node density based design via CCARAT.