The Computer Algebra Systems in Mathematics Education : A Review of Recent Research

Kwon, Oh-Nam,Shin, Eun-Ju,Shon, Bo-Kyung 이화여자대학교 교과교육연구소 2001 East west education Vol.18 No.-

This study examines the potential role for Computer Algebra Systems(CAS) in such an educational context, particularly their potential to get students more engaged in the learning of mathematics as well as to reduce the "strangle hold" of prerequisite algebraic skills, in courses such as functions, introductory calculus. What is the present status of and near-future outlook for computer algebra in Korean secondary schools? The answer that arises from this review of available fact is: bright with promise, but still dim. Several recent developments have set the stage for an acceleration in the dissemination rate for CAS to high schools. However, this review of some past and present conditions indicates that many years will pass before computer algebra is impacting high school mathematics as much as hand-held calculators are doing now.

미분없는 칼만필터 학습 알고리즘을 이용한 순환신경망의 파라미터 추정

권오신 국립7개대학공동논문집간행위원회 2004 공업기술연구 Vol.4 No.-

Recurrent neural network(RNN) trained with gradient based such as real time recurrent learning has a drawback of slow convergence rate. This algorithm also needs the derivative calculation which is not trivialized in error back propagation process. In this paper a derivative free Kalman filter for training a fully connected RNN is presented in a state space formulation of the system. A derivative free Kalman filter learning algorithm makes the RNN have fast convergence speed and good tracking performance without the derivative computation. Through experiments of nonlinear channel equalization, performance of the RNN with a derivative free Kalman filter algorithm is evaluated.

언센티드 칼만필터를 이용한 순환신경망 학습 및 채널 등화에의 응용

권오신 국립7개대학공동논문집간행위원회 2003 공업기술연구 Vol.3 No.-

Recurrent neural networks have been successfully applied to communications channel equalization. Major disadvantages of gradient-based learning algorithms commonly employed to train recurrent neural networks are slow convergence rates and long training sequences required for satisfactory performance. In a high-speed communications system, fast convergence speed and short training symbols are essential. This paper presents decision feedback equalizers using a recurrent neural network trained with Kalman filtering algorithms. The main features of the proposed recurrent neural equalizer utilizing unscented Kalman filter (UKF), are fast convergence rates and good performance using relatively short training symbols. Experimental result is presented to evaluate the performance of the proposed approaches over a conventional recurrent neural equalizer.

확장된 칼만필터를 이용한 순환신경망의 훈련 알고리즘

권오신 국립7개대학공동논문집간행위원회 2005 공업기술연구 Vol.5 No.-

Recurrent Neural network trained with gradient based learning algorithm has a drawback of slow convergence rates and long training sequences required for satisfactory performance. In a high speed communications, fast convergence speed and short training symbols are very important conditions. This paper presents decision feedback equalizers using a recurrent neural network trained with Extended Kalman Filter (EKF). The main features of the proposed EKF algorithm are fast convergence rates and good performance using short training symbol. Through experiments of channel equalization, performance of the recurrent neural networks with the EKF is evaluated.

침지식 한외 여과막을 이용한 무산소/혐기 교대운전형 반응조의 질소·인처리에 관한 연구

신대윤,김동임,권오상 조선대학교 환경공해연구소 2004 環境公害硏究 Vol.18 No.-

Nowadays, Water is deteriorating with several reasons such as increase of wastewater which is flowed into river and limitation of water resource. In this study, reuse water system was configurated using submerged membrane bioreactor(SMBR) system consisted of anoxic, selector, and aerobic tank with membrane to concentrate on plans for securing of water resource by reusing wastewater treatment effluen. This study was examined the feasibility of applying a Intermittently Internal Recycle Membrane Bioreactor to household wastewater treatment. The bioreactor was intermittently recycle to alternate anaerobic/anoxic condition while find was entered the early stage of anoxic period and membrane filtration occurred during aeration period. With about 5,000㎎/L of MLSS , 94.4% of TCOD_(Mn), 49.6% of T-N and 56.8% T-P, With about lO.OOO㎎/L of MLSS 94.0% of TCOD_(Mn), 51.3% T-N and 49.7% of T-P and With about lO.OOO㎎/L of MLSS (anoxic 1hr, anaerobic 2hr) 96.6% of TCOD_(Mn), 67.2% of T-N and 53.0% of T-P could be removed. Therefore, this study confirmed the possibility of the domestic water treatment using membrane bioreactor process with Intermittently internal recycle.

주파수 영역에서 선형시스템의 새로운 간략화법

權五臣 群山大學校自然科學硏究所 1990 自然科學硏究 Vol.5 No.-

M.F. Hutton과 B. Friedland 또는 S.v. Rao가 제시한 Routh 간략화법은 연분수 전개하여 alpha-beta 또는 gamma-delta표에 의하여 계수를 구한 후 필요한 차수 이외의 항을 제거한 다음 역으로 유리화시키는 방법을 취하였기에 그 과정이 대단히 불편하였다. 본 논문에서 제시한 새로운 시스템 간략화법은 Routh 간략화법에서 지적되는 연분수 전개식을 사용하지 않고 계산이 간단한 새로운 방법을 제시하였다. 간략화 모델의 분모다항식은 Schwarz의 D-table을 이용하여 표에서 바로 읽어, 구할 수 있고, 분자다항식은 Pade 간략화법에서 사용한 멱급수 전개방식을 응용하는 기법을 사용하여 구했다. 본 논문의 특징은 원 시스템이 안정하면 간략화 모델 역시 반드시 안정하며 간략화 과정에서 Routh의 간략화 방법에 비하여 계산이 간단함을 들 수 있겠다. 앞으로 다변수계(Multivariable Input/Output System)와 시변계(Variant System)에 대하여 본 논문의 간략화법의 적용방법은 더욱 연구되어야 할 과제이다. A freguency domain approach for reducing linear, time-invariant systems is presented which produces stable approximations of stable original systems. The method is based upon the schwarz canonical form and pade approximation method. This method does not require the calculation of the alpha-beta(or gamma-delta) table which should be calcuated Routh approximation method. The coefficient of the denominator polynomial are obtained by schwarzs D-table and the coefficient of the numerator polynomial are obtained by moment matching technique.

Chlorella vulgaris의 세포막에서 일어나는 Glycine 흡수과정에 관한 연구

權五溶,辛昌男,吳炅煥,李錦洙 충남대학교 자연과학연구소 1981 忠南科學硏究誌 Vol.8 No.1

In order to datemine that glycine uptake in the cell membrane of Chlorella vulgaris is depend on the specificity of substrate and energy required, it has been investigated on the reaction velocity of glycine and certain carrier. Some effects on the transmural fluxes of glycine across the cell membrane were also detemined. 1. The time course of glycine uptake was a linear function of time to early 10 min, and increased in the steady state slowly. 2. Glycine influx had shown apparent affinity in the range of 0.001 mM to 10 mM solution of glycine and followed Michaelis-Menten Kinetics(Km-0.16 mM, Vmax=0.31 nM2.0x10^7 cells min). 3. Glycine influx with 1 mA IAA was reduced about 50 percentage, suggesting that glycine uptake process is energy-dependent. 4. Glycine uptake was inhibited by glutamic acid, alanine, phenylalanine, proline, and methionine with the exception of histidine. It was suggested that the inhibition was competeted with some amino acids described above.

鷄龍山 陸松群落 및 리기다松群落의 林床植生에 關하여

權五溶,辛昌男,吳炅煥 충남대학교 자연과학연구소 1979 學術硏究誌 Vol.6 No.2

A study was carried out to ascertain the standing crops, species composition, and relationships between the standing crops and soil nutrients in the Pine forest and the Pitch pine forest of Gyeryong Mt. Species compositions of the Pine forest and the Pitch pine forest were 36 and 20 species, and dominant species of them was Festuca ovina . Total live standing crops of ground vegetation, 215.28-631.67g/㎡ and 188.62-446.13g/㎡, were highest in September, and net productivities were 13.02-169.95g/㎡ and 12.62-109.58g/㎡, respectively. Total live standing crops were significantly correlated with the water content and the organic matter of soil in each forest, and comparatively with the total nitrogen and the exchangeable phosphorus in the Pitch pine forest.

Pinus koraiensis와 Pinus parviflora의 樹高에 따른 氣孔數 變異에 關하여

權五容,辛昌男,吳炅煥,方在旭 충남대학교 자연과학연구소 1980 學術硏究誌 Vol.7 No.2

Stomata1 distribution in relation to the height of Pinus parviflora and Pinus koraiensis was studied 1. Stomata1 bands per needle of P parviflora and P koraiensis were 8.60±0.62 - 11.47±0.74, 14.07±1.03 - 16.60±0.99 and the number of stomata per band were 382.0±8.80 404.27±26.16, 1,326. 67±87.78 - 2,286.58±214.57, respectively 2. The number of stomatal band was significantly different between 3, 4m and 5, 6m in P parviflora and between 5, 6m and 7m in P. koraiensis Consequently, it is suggested that stomatal frequency gradient associated with increasing height above the ground is correlated with the greater degree of exposure to light.

결찰양식이 교정용 브라켓과 교정선 사이의 마찰력에 미치는 영향

신현정,권오원,김교한 대한치과교정학회 1998 대한치과교정학회지 Vol.28 No.5

마찰력은 치아이동시 활주이동부에 유해한 인자로 인식되어져 왔으나 치아이동에 저항하는 고정원에 있어서는 유리한 인자로 받아들여질 수 있다. 즉 마찰력이 작은 결찰법들을 이용하여 효과적인 치아이동을 도모하는 반면 마찰력이 큰 결찰법들을 이용하여 브라켓의 걸림에 의해 치아이동이 거의 일어나지 않게 하면 고정원을 강화할 수 있다. 인공타액하에서 시간경과에 따른 교정선과 브라켓 사이의 마찰력 변화, 탄성 모듈과 스테인레스 강 결찰선을 이용하여 각각 결찰양식을 달리 하였을 때의 마찰력 변화 그리고 결찰재의 내료를 달리 하였을 때의 마찰력 변화를 알아보기 위하여 .018" ×.025" 슬롯의 상악 중절치용 standard edgewise twin 브라켓과 .017" ×.022" 스테인레스 강 교정선을 탄성 모듈, .009" 스테인레스 강 결찰선 그리고 .012" 스테인레스 강 결찰선을 이용하여 다양하게 결찰하였다. 또한 통상적인 방법으로 결찰한 탄성 모듈 결찰군을 결찰 직후와 1주 간격으로 4주간 마찰력을 측정하여 다음과 같은 결과를 얻었다. ·탄성 모듈 whole tie시 시간경과에 따른 마찰력은 4주 경과시 가장 높았으나 3주, 2주, 1주, 결찰 직후간에는 통계학적으로 유의한 차이가 없었다(P>0.05). ·탄성 모듈로 결찰시 마찰력은 twisting tie가 가장 높았고 double overlay tie, whole tie, half tie 순으로 나타났으나 twisting tie와 double overlay tie 간에는 통계학적으로 유의한 차이가 없었다(P>0.05). ·스테인레스 강 결찰선으로 결찰시 half tie 군이 whole tie 군보다 낮은 마찰력을 보였으며 ligature tying plier로 결찰한 경우가 needle holder로 결찰한 경우보다 더 높았고 .012" 결찰선을 이용한 경우가 .009" 결찰선을 이용한 경우보다 더 높았다(P<0.05). ·통상적인 방법으로 탄성 모듈과 스테인레스 강 결찰선을 이용하여 결찰한 경우 두 군간에 유의한 차이가 없었다(P>0.05). The frictional force has been considered as an harmful factor in an active unit where tooth movement occurs, but as an advantageous factor in anchor unit that resist tooth movement. That is, efficient tooth movement is planned by using ligation methods that have low levels of bracket-wire frictional force and the anchorage control can be achieved by using ligation methods that have high levels of bracket-wire frictional force that result in binding of the bracket accompanied by little or no tooth movement. The purpose of this study was to evaluate the frictional force generated between bracket and wire in accordance with the methods of ligation, the material of ligation and the passage of time under artificial saliva. Tested were 0.017×0.022inch stainless steel wires in standard edgewise twin brackets for upper central incisors in a 0.018-inch slot. The wires were ligated into the brackets with elastomeric modules and stainless steel ligatures. Whole tie, half tie, twisting tie and double overlay tie were done with elastomeric modules. With 0.009-inch stainless steel ligature whole tie and half tie were done by needle holder and whole tie by ligature tying plier. With 0.012-inch stainless steel ligature whole ties were done by needle holder. Whole tie groups of elastomeric module were kept in artificial saliva bath at 37℃ for 28 days. The frictional force was recorded by means of an Instron universial testing instrument (4202 INSTRON, Instron Co., U.S.A.) at initial, 7, 14, 21, and 28 days. The results for ligated samples in a simulated oral environment revealed the following: ·In elastomeric module whole tie, 28days group was significantly greater mean static frictional force than any other group but there were no significant differences among any other group (p>0.05). ·Elastomeric module twisting tie were significantly greater mean static frictional forces than any other ligation method but there were no significant differences between twisting tie and double overlay tie(p>0.05). Twisting tie, double overlay tie, whole tie, half tie showed differences in decreasing order. ·Stainless steel half tie produced lower mean static frictional force than whole tie, ligature tying plier produced greater mean static frictional force than by needle holder and ligation with 0.012-inch stainless steel ligature produced greater mean static frictional force than with 0.009-inch stainless steel ligature (p<0.05). ·There were no significant differences between the mean static frictional forces of elastomeric whole tie and stainless steel whole tie (p>0.05).