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.

기대빈도를 활용한 새로운 상대집중지수의 제안

남기성,오민홍,홍현균,Nam, Ki-Seong,Oh, Min-Hong,Hong, Hyun-Guyn 한국통계학회 2008 응용통계연구 Vol.21 No.4

본 연구는 기존의 순위만 고려하는 집중도를 보완하여 기대빈도를 이용한 새로운 상대집중지수 NOHI(Nam-Oh-Hong Index)를 제안하고, 이를 지역별 직업별 종사자 수에 적용함으로써 지역별 특화 직종 분포에 활용하는데 있다. 지역 간 특화정도를 보여주기 위해 개발된 입지계수(LQ)의 경우, 해당산업의 지역 내 비중을 상대적으로 고려하지 못함에 따라 지역 내 특성화를 반영하지 못하는 한계를 내포하고 있다. 본 연구에서 제안하는 NOHI는 이러한 단점을 보완하여 산업 및 직종의 지역간 지역내 특화도를 동시에 나타낼 수 있다. 본 연구에서 제안하는 NOHI를 활용하여 분석한 결과 서울은 경영 회계 사무관련직의 특화도가 높은 것으로 나타났으며, 부산은 기계 재료관련직의 특화도가 높은 것으로 나타났다. The purpose of this study is to introduce a relative specialization index, the Nam-Oh-Hong Index(NOHI) and to investigate regional distribution of occupational specialization using the newly developed index. Compared with Location Quotient(LQ), the advantages of the index is that the NOHI enables comparison between inter-regional and intra-regional concentration of employment possible at the same time. The results of the specialization analyses show that Seoul is specialized in management, book-keeping and office related occupations, whereas Busan in machine and material related occupations.

Bacillus sp. Ye-1213이 생산하는 chitinase의 동정, 분리정제 및 특성

오두환,허남윤,백무열 연세대학교 산업기술연구소 1990 논문집 Vol.22 No.1

국내 해변 연안의 해변의 토양으로부터 chitinase 활성이 우수한 균주를 분리하고 동정하여 Bacillus sp. YE-1213으로 명명하였다. Chitinase를 생산하기 위한 최적 배양조건은 1.0%(w/v, dry base) Colloidal chitin, 1.0%(w/v) Tryptone, 0.05%(w/v) MgSo₄·7H₂O, pH 8.0, 30℃, 배양시간 48시간이었다. 효소는 (NH₄)₂SO₄분별침전, affinity adsorption, Sephadex G-200 gel filtration의 과정을 거쳐 정제한 결과 비활성 81.32units/mg, 정제도 16.7배, 수율은 15.8%이었다. 정제된 효소는 최적 반응조건은 pH 6.0, 40℃ 이었으며, 온도에 대한 효소안전성은 40℃까지는 매우 안정하였고 pH에 대한 안정성은 pH 5.0-9.0에서 안정하였다. 정제된 효소의 Km 값은 1.74mg/ml이었고 PCMB, I₂, ?? ion, ?? ion 에 의해 저해되었으며 ?? ion, ?? ion 및 ?? ion 에 의해 1.21배, 1.12배, 1.18배의 효소활성이 증가하였다. A bacterium with the highest chitinase activity selected from the soil and identified as a Bacillus sp. YE-1213. The optimal condition for the production of chitinase was as follows; 1.0% (w/v, dry base) colloidal chitin, 1.0%(w/v) tryptone, 0.05%(w/v) MgSO₄·7H₂O, pH8.0, 30℃, 48 hrs. The chitinase was purified about 16.7 folds by ammonium sulfate fraction, affinity adsorption and Sephadex G-200 gel filtration. Optimal temperature and pH for the enzyme activity were 40℃ and pH 6.0. The enzyme was stable between pH 5.0-9.0 and up to 40℃. Its activity was activated by ??, ??, and ?? while inhibited by PCMB, I₂, ?? and ??.

Sol-Gel법으로 제조된 PZT Thin Film

오지현,권근희,김남철 공주대학교 생산기술연구소 2002 論文集 Vol.10 No.-

This paper presents ferroelectric Pb(Zr_0.52Ti_0.48)O_3 (PZT) thin film by sol-gel synthesis with metal-organic precursors. Sol-gel reaction sequences with metal-organic precursors were confirmed through DTA and FT-IR measurements and perovskite phase formation was investigated by rapid thermal annealing technique. The structural and morphological properties of PZT thin film were investigated by XRD and SEM. Perovskite phase PZT single phase was appeared at temperature of 650 ℃ and the second phase, pyrochlore, was decreased as increasing the annealing temperature, which was clearly indicated by investigating the size of 'rosette structure' and pyrochlore phases at different annealing temperatures. The P-E loop measurement indicated the relation of the applied voltage vs. domain alignments in the PZT thin film system.

화산경관 분출순서 연구 : 화순지역 중심

오남삼 제주대학교 관광개발연구소 1986 관광개발연구소 논문집 Vol.3 No.1

Titanium의 切削에서 Saw-toothed Chip의 切削 Energy에 관한 硏究

吳錫炯,徐南燮 全北大學校 1987 論文集 Vol.29 No.-

In metal cutting, various types of chips are produced. W. Rosenhain classified them into flow-type, shear-type, pluck-off-type and tear-type. In the experiment, Nakayama found the chips whose shapes were saw-toothed-like and which were produced periodically. Since then this type of chip has been called saw-toothed chip. When this chips occur, the cut surface is smooth and the required cutting force is small. Nakayama and Ueda insist that saw-toothed chip is formed by the brittle fracture, the vibration, and etc. They studied about the effect of cutting depth, true rake angle on the slip and pitch. But there has not been report on the cutting energy with saw-toothed chip. This report shows how the depth of cut, true rake angle, and cutting speed effect on the cutting energy in machining titanium. The results are as foolows: 1. The specific cutting force decreases with the increase of the pitch. 2. The normal stress and the shear stress on the shear plane decrease with the increase of cutting depth. They are almost independent on the variation of true rake angle. 3. The unit friction energy on the tool face and the unit shear energy on the shear plane decrease with the increase of true rake angle and cutting depth. 4. The saw-toothed chip is formed in the case that the depth of cut is deeper than 0.03mm, and the smaller the true rake angle is, the larger the range, where saw-toothed chip is formed, is.

연령에 따른 흰쥐 망막 속얼기층의 미세구조 변화

오원영,고정식,양남길,안의태,박경호 순천향의학연구소 1995 Journal of Soonchunhyang Medical Science Vol.1 No.2

이 실험은 연령에 따른 흰쥐 망막 속얼기층의 미세구조적 변화를 관찰하기 위하여 시행하였다. 실험동물로는 생후 3개월(어린 흰쥐), 12개월(젊은 흰쥐) 및 30개월(늙은 흰쥐)된 Fisher계통 344흰쥐를 사용하였다. 각 동물은 4% chloral hydrate로 마취한 후 2.5% glutaradehyde-1.5% paraformaldehyde로 관류 고정한 다음, 안구를 적출하여 톱니둘레를 다라 절단한 후 시신경원반외측의 일정부위에서 망막조직을 떼어내었다. 떼어낸 조직은 2.5% glutaradehyde- 1.5% paraformaldehyde 고정액에 다시 고정한 후, 1% osmium tetroxide액에 또 다시 고정하였다. 고정된 조직은 ethyl alcohol과 acetone으로 탈수한 후 araldite혼합액에 포매하였다. 포매된 조직은 LKB-V ultratome으로 얇은 절편을 작성하여 uranyl acetate와 lead citrate로 염색한 후 JEM 100CX-Ⅱ 전자현미경으로 관찰하여 다음과 같은 결론을 얻었다. 1. 무축삭신경원의 세포질돌기는 세포질의 전자밀도, 연접소포의 종류 및 양에 따라 4종류 구분되었다. 2. 속얼기층에서 관찰되는 신경연접의 형태는 연접리본복합체외에 4종류의 일반신경연접을 관찰할 수 있었으나, 연령증가에 따른 연접형태의 미세구조적 변화는 관찰할 수 없었다. 3. 연령이 증가함에 따라 부챗살아교세포의 상대적 영역이 넓어졌다. 4. 연령이 증가함에 따라 무착삭신경원과 신경절세포의 가지돌기안에 수초구조, 용해소체, 잔여소체가 자주 관찰되었다. 이상의 결과를 종합해 보면 흰쥐의 망막속얼기층은 연령이 증가하면 무축삭신경원과 신경절세포는 기능이 점점 약해지므로 부챗살아교세포의 영역이 상대적으로 더 넓어진다고 생각된다. Morphological differences among the inner plexiform layers at different age groups have been studied in young(three months old), adult(twelve months old) and old(thirty months old) Fisher stain 344 rats. Under anethesia, 2.5% glutaraldehyde- 1.5% paraformaldehyde solution was perfused through the heart. Pieces of the tissue taken from the posterior region of the retina were fixed in 2.5% glutaraldehyde- 1.5% paraformaldehyde, and in 1% osmium tetroxide followed by fixation embedded in aralditse mixture. Ultrathin seciton were statined with uranyl acetate and lead citrate solution and were observed with JEM 100CX-II electron microscope. The results were as follows: 1. Four types of amacrine cells were found according to their electron densities, and kind and amount of the synaptic vesicles, were found, i.e., dark amacrine cell with clear vesicles(Al cell), light amacrine cell with clear vesicles(A2 cell), dark amacrine cell with clear and granular vesicles(A3 cell) and light amacrine cell with clear and granular vesicles(A4 cell) 2. In the inner plexiform layer, there appear two types of synapses : 1) synaptic ribbon complex and 2) conventional synapses. Conventional ones exhibited four different types, showing, i.e., prominent presynaptic density(type 1), prominent postsnaptic density(type 2), prominent pre-and postsynaptic densities(type 3), and lesser prominent pre-and postsynaptic densites. 3. Territories of the Muller cells were expanded during aging. 4. Myelin figures, lysosomes, lipofuscin granules and lipid droplets were frequently observed in the amacrine and ganglion cells of the adult and old rats. From the above results, it was suggested that functions of the bipolar, amacrine and ganglion cells were diminished gradually, whereas territories of the Muller cells were expanded during aging.

濟州道 固有文化의 保存 및 宣揚方案에 관한 硏究 : 濟州道 指定文化財의 觀光資源化

吳南三 濟州大學校 社會科學大學 社會發展硏究所 1987 社會發展硏究 Vol.3 No.-

변이주인 Trichoderma reesei YC-3156이 생산하는 Cellulase에 관한 연구

오두환,안순철,유주현,허남윤 연세대학교 산업기술연구소 1987 논문집 Vol.19 No.2

After the treatment 15 strains of Trichoderma sp. and 4 isolates with N-methyl-N´-nitro-nitrosoguanidine, T. reesei YC-3156 among the mutants showed the highest cellulase activity. The Avicelase of T. reesei YC-3156 was purified by 70% ammonium sulfate fractionation, dialysis, DEAE-Sepharose column chromatography and Sephadex G-100 Gel-filtration. With the result of the procedures, its purification degree was 13 folds, yield 9.3% and specific activity 0.9 unit/mg. The homogeneity and the molecular weights of the purified Avicelase were determined by SDS-polyacrylamide gel electrophoresis, it was electrophoretically homogeneous and showed the molecular weights of 46,000-48,000. The purified Avicelase was stable between pH 4.0 and pH 5.0 and it was inactivated rapidly above 60℃.

.Pseudomonas stutzeri 감염에 의한 맥락총염에서 초래된 포착성 측뇌실 확장 1예

김남곤,권오영,박기종,최낙천,임병훈 대한신경과학회 1997 대한신경과학회지 Vol.15 No.2