• Research in Mathematical Education
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• v.11 no.3
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• pp.209-218
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• 2007

The purpose of this study is to create an interactive tool Geometry Player for geometric explorations. In designing this software, we referred to van Hiele's geometric learning theory of and Duval's cognitive comprehension theory of geometric figures. With Geometry Player, it is easy to construct and manipulate dynamic geometric figures. Teachers can easily present the dynamic process of geometric figures in class, and students can use it as a leaning tool to construct geometric concepts by themselves. It is hoped that Geometry Player can be a useful assistant for teachers and a nice partner for students. A brief introduction to Geometry Player and some application examples are included in this paper.

• IE interfaces
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• v.8 no.3
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• pp.133-139
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• 1995

Free from curves and surfaces are frequently used in designing engineering products such as car, ship, airplane, and hosing of electronic households. In many aspect, it is very nice to use the cutter radius compensation function of CNC controller when contour machining a 2-dimensional curve. However, if the 2D curve is a parametric spline, it is not easy to apply the cutter radius compensation function of CNC controller to the NC data obtained from many commercial CAM system. This is mainly due to the error magnification effect when offsetting line segments with inevitable round-off error at their vertices. Proposed in this paper is an approach to contour machining a 2D parametric spline while using cutter radius compensation. Some implementation results are included.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2006.11a
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• pp.457-460
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• 2006

This study is to investigate the variation characteristics of run-up height over sandy beach due to the plane distribution of submerged breakwaters. In this study, Three-Dimensional numerical model with Large Eddy Simulation, which is able to simulate directly WAve Structure Seabed interaction (hereafter, LES-WASS-3D) has been newly developed. A comparison between the numerical model and existing experimental results was made to verify accuracy of newly proposed LES-WASS-3D model, and showed fairly nice agreement. In addition, based on the LES-WASS-3D model, the variation characteristics of run-up height over sandy beach are discussed with relation to the offshore distance and opening width of submerged breakwaters.

• The Journal of Asian Finance, Economics and Business
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• v.3 no.3
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• pp.5-15
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• 2016

This study examines whether Korean rating agencies such as Korea Investors Service (KIS), National Information & Credit Evaluation (NICE), and Korea Ratings Corporation (KR), incorporate corporate governance into their corporate bond ratings in Korea. We find that the Korean rating agencies assign higher ratings to the bonds issued by Chaebol (Korean business group) affiliated firms. Our results also indicate that those rating agencies give higher ratings to the bonds with greater foreign investor share ownership. Moreover, if the rating agencies value corporate governance, higher rated firms should issue bonds at lower yield to maturity. We discover that Chaebol affiliation is counted favorably by the rating agencies. We find that investors are willing to pay lower risk premium for bonds with higher institutional ownership, but higher risk premium to bonds with greater equity ownership in the form of depository receipts. Therefore, even if the rating agencies and investors in Korea consider corporate governance (Chaebol affiliation and ownership structure) an important determinant in bond ratings and the yields to maturity, they have opposite views on institutional ownership and share ownership in the form of depository receipts.

• Journal of the Korean Society of Food Culture
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• v.14 no.3
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• pp.225-231
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• 1999

Perception and knowledge on the diet among 651 women living in Inchon were surveyed by questionnaires in March through May, 1998. Respondents consisted of middle school girls(12.3%), high school girls(16.4%), and women in twenties(16.4%), thirties(18.9%), forties(15.7%) and fifties and over(20.3%). Ratio of high school graduates was the highest(37.0%) among respondents, and there was a tendency of less education with ages. Seventy-six percent of women practised the diet for the self-satisfaction of a nice figure, 20% for healing diseases, and 3.4% for attracting boy friends' or husbands' attention. The purpose of the diet was significantly different with ages(p<0.01). The diet methods which the respondents perceived effective and wanted to practise were exercise and food therapy. Average score of the knowledge on the diet was 8.27 out of 10, and significantly different with ages and education(p<0.05). Twenties showed the highest score and high school girls, thirties, middle school girls, forties and fifties and over were followed in decreasing order. Also the score was in decreasing order of graduates of college, high, elementary and middle school.

• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.1
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• pp.46-52
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• 2017

Social attention to information security field is inspired, and manpower demand forecast of this area is getting high. This study surveyed information security knowledge of practitioners who work in a field of information security such as computer and network system. We analyzed a connection between survey data, information protection job system that was suggested by NICE, IT skills that NCS and KISA classified and security field classification system. Base on data that analyzed, this study suggests a curriculum that trains professional manpower who perform duties in the field of information security. Suggested curriculum can be applied to 2 year college, 3 year college and 4 year college. Suggested curriculum provides courses that students who want to work in a field of information security must learn during the college. Suggested courses are closely connected to a related field and detailed guideline is indicated to each course to educate. Suggested curriculum is required, and it combines a theoretical education that become basis and a practical education so that it is not weighted to learn theory and is not only focusing on learning simple commands. This curriculum is established to educate students countermeasures of hacking and security defend that based on scenario that connected to executive ability. This curriculum helps to achieve certificates related to a field more than paper qualification. Also, we expect this curriculum helps to train convergent information security manpower for next generation.

• Bulletin of the Korean Chemical Society
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• v.25 no.2
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• pp.172-176
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• 2004

A highly selective membrane electrode based on1,3,5-triphenylpyrylium perchlorate (TPPP) is presented. The proposed electrode shows very good selectivity for sulfate ions over a wide variety of common inorganic and organic anions. The sensor displays a nice Nernstian slope of -29.7 mV per decade. The working concentration ranges of the electrode is 1.0{\times}10^{-1}-6.3{\times}10^{-6} $M with a detection limit of $4.0{\times}10^{-6}$ M (480 ng per mL). The response time of the sensor in whole concentration ranges is very short (< 6 s). The response of the sensor is independent on the pH range of 2.5-9.5. The best performance was obtained with a membrane composition of 32% PVC, 59% benzyl acetate, 5% TPPP and 4% hexadecyltrimethylammonium bromide. It was successfully used as an indicator electrode for titration of sulfate ions with barium ions. The electrode was also applied for determination of salbutamol sulfate and paramomycine sulfate.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.420-420
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• 2012

인류의 역사 이래로 하천관리에 있어서 치수는 주요 과제중의 하나였다. 대부분의 하천은 원활한 홍수 유통을 위해 직선화되었고 하폭은 확장되었다. 이로 인해 하천 생태계는 단순화되었고 홍수 피해 또한 줄지 않고 시가지 범람이라는 새로운 유형의 침수피해가 발생하였다. 최근까지도 홍수피해를 저감하고자 많은 노력을 기울이고 있고, 하천을 자연 친화형으로 설계, 복구하는 움직임이 활발하다. 하천을 설계함에 있어서 수치해석을 하고, 예측하는 것은 시간과 경제적인 장점으로 인해 많이 이용하고 있다. 본 연구에서는 대상지역을 프랑스 남부에 위치한 Var Catchemnt로 선정하였다. Var 유역은 $2,822km^2$의 면적, 총길이 125km, 최고 고도와 강 하구까지의 고도차가 3,000m의 급한 경사로 이루어진 유역이다. 이 지역은 매년 11월에서 1월 우기 때마다 빈번하게 홍수가 발생하는 지역으로 끊임없이 홍수에 따른 범람의 문제가 제기되고 있는 지역이다. 1994년 11월에 발생한 기록적인 폭우로 인해 최대유량 $3,500m^3/s$으로 관측되었고, 이 수치는 평균 유량의 50배에 이르는 유량이다. 이 홍수와 범람으로 인해 주변의 많은 시설이 피해를 입었으며, 도로가 유실되고, 인명피해도 상당했다. 본 연구에서는 수치해석을 위해 1차원 해석 프로그램인 DHI사의 MIKE11과 미공병단에서 개발한 Hec-Ras를 사용하였다. 홍수피해를 예방하기 위하여 가장 경제적이고 합리적인 방법은 제방의 높이를 변경하는 것으로 판단하여 수치해석을 실시한 후, 실제 데이터와의 비교를 통해 홍수를 예방하기 위한 제방의 높이를 결정하였다. Var 유역에 홍수를 예방하기 위해서는 강의 하구 쪽의 제방을 높일 필요가 있다고 판단되었다.

• Journal of Gifted/Talented Education
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• v.3_4 no.1
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• pp.148-157
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• 1994

"Is a given boy or girl gifted in physics\ulcorner" That is a very complicated question and it is not easy to answer it as creativity and talents have many aspects. The lecture is devoted to analysis of several of them. In particular, we shall discuss the following points: 1) "Poets in physics". Some pupils have a seldom ability to create very beautiful, intellectual constructions starting from very few assumptions. Any building consists of commonly used bricks or other building elements, any book contains only several tens of commonly used letters or other graphic elements, also any painting may be created by appropriate use of several colors. Some buildings are nice, some not. Some paintings are beautiful, some not. Certain pupils, by appropriate use of several simple laws, are able to create beautiful constructions. They are like poets writing poetry by using several tens of letters known to everybody. 2) "Free hunters". Some pupils solve even very typical problems in a very untypical ways. Their independence in thinking is especially valuable. 3) "Small discoverers". Even very rich syllabuses do not contain whole physics. Some pupils e.g. during solving problems discover laws or rules that are absent in the syllabus. For example, some of them are able to make use of symmetry or dimensional analysis without any preliminary knowledge of that matter. The considerations are illustrated with different examples taken from physics or mathematics. The subject is very large and, of course, we are not able to present the problem in a complete way.o present the problem in a complete way.

• The Korean Journal of Quaternary Research
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• v.2 no.1
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• pp.1-11
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• 1988

L'analyse des galets fractures decouverts sur les sols d'habitat de la grotto du Lazaret permet de penser que la cassure des galets se serait produite sur place dans la grotte, soit par des actions naturelles, soit par des actions des hommes prehistoriques. D'apres la comparaison des resultats obtenus par 1'etude exprimentale, les cassures des galets sont liees a plusieurs modes de fraturation. On peut seulement dire que les trois modes (1,3 et 5) sont susceptibles de donner des indications sur 1'aspect intentionnel de certains types de fracturation.