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.

Thermocouple을 이용한 Buchanan Plugger 표면의 온도상승 분석

조진숙,황윤찬,김선호,황인남,최보영,정영진,정우남,오원만 전남대학교 치의학연구소 2003 구강과학 Vol.15 No.4

This study was performed to confirm the actual temperature rise on the surface of Buchanan plugger by evaluating the temperature rise on the surface of it, the peak temperature of pluggers of various size using thermocouple. The heat carrier system 'System B Heatsource' (Model 1005, Analytic Technologies, USA) and the Buchanan pluggers of F, FM, M and ML sizes are used for this study. The temperature was set to 200 which Dr. Buchanan's "Continuous wave of condensation" technique recommended on digital display and the power level on it was set to 10. The touch mode was used. Five thermocouples were placed in direct contact with the surface of each size of Buchanan's pluggers at 1 ㎜ increments from the tip to the 4 ㎜ length of shank. Each thermocouple was secured with cyanoacrylate adhesive and orthodontic resin block. The two wire leads of each thermocouple were connected to the appropriate channels of Data Logger. This was configured to simultaneously record input from the five thermocouples. The heat control spring was touched for 1, 2, 3, 4 and 5 seconds, and the temperature rise on the surface of the pluggers were measured at 1 sec intervals for more than 5 seconds with an accuracy of 0.01. Ten trials was determined for each plugger. The average of temperature rise and standard deviation was calculated for each size of plugger. The data were statistically analyzed by one-way ANOVA to determine their significance. The results as follows. 1. The position at which the temperature peaked was approximately at 1∼2㎜ far from the tip of Buchanan plugger (p<0.01). 2. The peak temperature was 215.25±2.28℃ in F plugger, 185.94±2.19℃ in FM plugger, 169.51±9.12℃ in M plugger, and 160.79±1.27℃ in ML plugger and the peak temperature was highest in F type and followed by, in descending order, FM type, M type. ML type showed the lowest peak temperature (p<0.01). This results suggest that the actual temperature on the surface of the pluggers does not correlate well with the temperature set on digital display. Heat concentrates around the tip. The larger plugger reveals lower temperature rise relatively.

電力系統 運用을 고려한 2000년대 原子力 長期展望

南輔祐 단국대학교 1990 論文集 Vol.24 No.-

In 1970s, investment on nuclear power plants was actively promoted. After TMI and Chernoville accidents in 1980s the safety problem and cost increments of constructions reduce investment on nuclear power plants. Recently, polutions and site problems increase the needs of nuclear. Until 2030, to support economic developments and improvements of living, standards electricity demand would be ten times than that of 1988 in Korea. This paper reviews trends of nuclear investment in the world and analyzes the mix of power plants concern with system operations. Also this study develops power plants mix evaluation system(MES) and prospects the new power plants demand and economic analysis for the period of 1989∼2030 through the MES. The main results can be summarized as follows : 1) This study develops the long-range power plants mix evaluation system(MES) which simplifies the probablistic simulation method of WASP. 2) Considering electric power system operations, the maximum capacity ratio of nuclear power plants could be 45 percents. 3) Until 2030, about one hundred and sixty new power plants should be introduced and the range of new nuclear introductions becomes from 36 to 56 units. 4) Sensitivity analysis shows that the standardization of considerations and optimization of managements are more important than the choice of nuclear and coal-fired plants.

가스부문의 중장기 연구개발계획 수립에 관한 연구

남보우 단국대학교 1996 論文集 Vol.30 No.-

In this paper, a two-stage and top-down approach of mid and long-term R&D planning of public corporation is proposed to incorporate the characteristics of publicity and to overcome the complexity of the real world planning. Unlikely to R&D planning of private company, the total investment size of R&D of public corporation is institutionally determined. A top-down approach is developed to adopt this feature. The proposed approach has six stages. The scope of the R&D technology is determined in the first stage by analysis of business area and public role. In the second and third stage, some important factors of management and environment should be derived and analyzed to develop the objectives and strategies. In the fourth stage, global R&D plan is developed by various techniques. We develop the detailed plan for the individual research area in the fifth stage. The plan of the fund, manpower, facilities and organization should be developed in the last stage. The proposed approach is applied to develop the mid and long-term R&D planning of Korea Gas Corporation and the proposed approach is useful to develop R&D plan.

多目的댐 水力發電의 經濟性評價 및 費用配分硏究

南輔祐 단국대학교 1995 論文集 Vol.29 No.-

Unlikely to single purpose projects, it needs to adopt the different approach of economic analysis and cost allocation of multiple purpose dam. Specially, multi-purpose dan produces electricity and supplies it to total electric system. For the economic analysis and cost allocation, the value of multi-purpose dam should be evaluated within the total electric system. There are several existing studies which suggest theoretically fine method. However, the result of existing studies has some weak points for real applications. Also, it needs to refine the method of economic analysis and cost allocation of multi-purpose dam in Korean applications. This paper suggests a power generation simulation model which includes unserved energy costs for the social welfare and probablistic simulation model for the power plants failure. This model has some benifits of the simplification of power demand and the rational production costing. There are some suggestions for application of economic analysis and cost allocation in Korea. it needs to expand the kinds of benifits of multi-purpose dam and adopt the power generation simulation model.

玄蔘의 Saponin 成分 檢索 : on the Saponin of the Radix

남인숙,배병숙,최보향,최인수,최태수,김동언,김언주,정미영,조규옥 曉星女子大學校 藥學大學 學生會 1988 曉星藥誌 Vol.4 No.-

Crude saponin(100g) were obtained by extracting the radix(5kg) of Scrophalariae koraiensis Nakai. Crude saponin were positive in the Liebermann-Burchard test. We observed 5 sports by TLC using BuOH saturated with H_2O : ethyl acetate : water(4:1:5, upper phase) as solvent and 1% Ce(SO_4)_2 in 10% H_2SO_4 as a color former. We divided into 3 fractions by common column chromatography using BuOH saturated with H_2O : ethylacetate : water(4:1:5, upper phase) as solvent.

不確實性을 고려한 電力部門의 設備投資에 관한 硏究

南輔祐 단국대학교 산업연구소 1989 산업연구 Vol.12 No.-

代替에너지 技術評價에 관한 硏究

南輔祐 단국대학교 산업연구소 1992 산업연구 Vol.15 No.-

대체탄력도를 갖는 확장선의 시장점유율 모형

남보우 단국대학교 1999 論文集 Vol.34 No.-

There are numerous researches on the consumer behavior or producer behavior which results the market share. The conventional approach in the economics adopts the utility function and the optimization behavior of consumer or producer. The other approach in the managemant research assume some heterogeneity of consumer or some probability function of the price of commodities. These approaches results some difficulties in the representation of utility function or the validity of the assumption. This paper derives a market share function of the commodities on the expansion path which have constant elasticity of substitution. This market share function has the same validity of consumer behavior in the economics. Also this market share function does not adopt the utility function. These give the theoretical foundation and simplicity for the modeling. This result can be utilized for the modeling in the area of inter-industry analysis, the choice problem of commodity or technology and the energy system modeling.

Ni添加 CV黑鉛鑄鐵의 祖織과 機械的性質 및 熱物性値에 關한 硏究

南泰運,許甫寧,徐弘三 慶尙大學校 1987 論文集 Vol.26 No.1

In this sthdy, an easy production method of CV graphite cast with iron with small adition of NI which is known as the elements of the graphitizon was inverstigated. And so, the effects of physical, mechanical and thernal properties by fading time, carbon equivalent and Ni addition after the treatments with spheroidizer(Fe-Mg), were also investigated. The results obtained from this study were as follows: 1. With an increase of carbon equivalent the CV ratio was a little increased but with an increase of addition of Ni plus Mg the graphite numbers and CV rato were greatly increased. And so, the form and distribution of graphite were homogenized. 2. With an addition of Ni the ferrire ratio were decreased and the parlite ratio were a little increased. 3. With an increase of CE and fading time the mechanical properties (tensile strength, ased. And so, in case of Mg an Ni plus Mg addition the mechanical properties were greatly increased. 4. With an incease of CE and fading time the thermal properties(thermal diffusivity and conductivity ) were increased but with addition of Ni plus Mg the thermal properties were speroidal graphite ratio. 5. For the addition of Ni plus Mg the results were obtained that the decrease of lading effect the increase of inoculation effect, the increase of CV graphite ratio.