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마이크로 컴퓨터를 활용한 수학 교수 , 학습법 개발에 관한 연구
김창동,이태욱 ( C . D . Kim,T . W . Lee ) 한국수학교육학회 1988 수학교육 Vol.27 No.1
We are at the onset of a major revolution in education, a revolution unparalleled since the invention of the printing press. The computer will be the instrument of this revolution. Computers and computer application are everywhere these days. Everyone can`t avoid the influence of the computer in today`s world. The computer is no longer a magical, unfamiliar tool that is used only by researchers or scholars or scientists. The computer helps us do our jobs and even routine tasks more effectively and efficiently. More importantly, it gives us power never before available to solve complex problems. Mathematics instruction in secondary schools is frequently perceived to be more a amendable to the use of computers than are other areas of the school curriculum. This is based on the perception of mathematics as a subject with clearly defined objectives and outcomes that can be reliably measured by devices readily at hand or easily constructed by teachers or researchers. Because of this reason, the first large-scale computerized curriculum projects were in mathematics, and the first educational computer games were mathematics games. And now, the entire mathematics curriculum appears to be the first of the traditional school curriculum areas to be undergoing substantial trasformation because of computers. Recently, many research-Institutes of our country are going to study on computers in orders to use it in mathematics education, but the study is still starting-step. In order to keep abreast of this trend necessity, and to enhance mathematics teaching/learning which is instructed lecture-based teaching/learning at the present time, this study aims to develop/present practical method of computer-using. This is devided into three methods. 1. Programming teaching/learning method This part is presented the following five types which can teach/learn the mathematical concepts and principle through concise program. (Type 1) Complete a program. (Type 2) Know the given program`s content and predict the output. (Type 3) Write a program of the given flow-chart and solve the problem. (Type 4) Make an inference from an error message, find errors and correct them. (Type 5) Investigate complex mathematical fact through program and annotate a program. 2. Problem-solving teaching/learning method solving This part is illustrated how a computer can be used as a tool to help students solve realistic mathematical problems while simultaneously reinforcing their understanding of problem-solving processes. Here, four different problems are presented. For each problem, a four-stage problem-solving model of polya is given : Problem statement, Problem analysis, Computer program, and Looking back/Looking ahead. 3. CAI program teaching/learning method This part is developed/presented courseware of sine theorem section (Mathematics I for high school) in order to avail individualized learning or interactive learning with teacher. (Appendix I, II)
김창동,정의봉 대한기계학회 1993 대한기계학회논문집 Vol.17 No.6
본 연구에서는 구조계와 제어계가 결합된계에 대하여, 성능 평가함수의 구조 설계변수에 대한 감도를 Riccati방정식으로부터 직접 해석할 수 있는 효율적인 방안을 제시하여 동시최적설계가 가능토록한다. 그리고 유색잡음의 불규칙 노면입력을 받는 차체탄성을 고려한 Hac의 2륜 차량의 모델에 LQG제어를 행한 경우에 대하여, 본 연구 방법을 적용시켜 동시 최적화를 수행한 제어성능 특성을 종래의 최적제어만에 의한 제어성능과 비교, 검토 한다. 구조설계변수로는 현가장치의 강성특성, 감쇠특성 및 현가장치 지지점의 위치로 선정한다. This paper presents a method for the simultaneous optimal design of structural and control systems. Sensitivities of performance index with respect to structural design variables are analyzed. The structural design variables are optimized to minimize the performance index by use of conjugate gradient method. The method is applied to a half model of an active vehicle suspension system with elastic body moving on a randomly profiled road. The suspension control force of an optimally controlled system in the presence of measurement errors are calculated by use of linear quadratic Gaussian control theory and Kalman filter theory. The performance index contains ride comfort, road holding and working space of suspension. The structural design variables taken are stiffness, daming properties and the position of the suspension system. The random road profile considered as colored noise is shaped from white noise by use of shaping filter. The performance of an optimal simultaneous structure/control system is compared with that of an optimal controlled system.
주파수 가중치를 고려한 승차감의 향상을 위한 차량 현가장치의 동시최적화
김창동,정의봉 한국소음진동공학회 1995 소음 진동 Vol.5 No.1
This paper presents the simultaneous optimal design of structure and LQG control systems for the improvement of riding comforts of active vehicle suspension systems. The performance index of riding comforts is extended to include frequency-weighted acceleration in the quadratic cost functional. Janeway human response curve with respect to acceleration is used to verify the usefulness of the presented method. The method is applied to a half model of an active vehicle suspension systems with elastic body moving on randomly profiled road. The values of stiffness of suspensions are used for the structural design variables. The conjugate gradient method is used for optimization. The simulated results of simultaneous optimization with frequency-weighted cost functional are compared with those without frequency- weighted cost functional.
김창동,김수일,이준환 한국지반공학회 2008 한국지반공학회논문집 Vol.24 No.11
In this study, a new method for estimating the undrained shear strength su of saturated clays using piezocone penetration test (CPTu) result is proposed. This is to develop more effective CPTu-based su estimation method at lower cost with less uncertainty. For this purpose, a marine clay deposit is selected and tested through extensive experimental testing program including both in-situ and fundamental laboratory tests. The proposed method is based on a correlation between the undrained shear strength su and the cone resistance qt, without introduction of the total overburden stress into the su-qt correlation. As a result, no additional testing procedure for collecting undisturbed soils samples is required, which can reduce overall testing cost. To verify the proposed method, 4 test sites, which consist of a variety of soil conditions, are selected and used for comparison between measured and predicted undrained shear strength. From comparison, it is seen that predicted values of su using the proposed method match well those from measured results.
High-Performance Bottom-Gate TFT Fabricated by Employing SPC with Magnetically-Assisted RTA
김창동,김창연,이석우,서현식,강인병 한국물리학회 2009 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.54 No.1
An n-type TFT, based on the conventional a-Si TFT process, having advanced solid phase crystallization (A-SPC) with magnetically-assisted RTA has been developed on a glass substrate. Even though the A-SPC process has a temperature higher than the glass transition temperature, it showed no glass warpage but only manageable glass shrinkage, so processing on a glass substrate is possible. The n-type TFT with A-SPC process shows higher current drivability and device reliability than an a-Si TFT, which overcomes the drawbacks of a conventional a-Si TFT backplane. It also shows relatively good short-range device uniformity to solve the problem of conventional poly-Si TFTs. The n-type backplane with A-SPC technology was verified by manufacturing a 15-inch AMOLED panel.