• Title/Summary/Keyword: 한국수학

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Survey of Elementary and Middle School Gifted Students' Perceptions on Research Ethics (초ㆍ중등 영재학생의 연구윤리 의식 조사)

  • Lee, Jin-A;Yoo, Mi-Hyun
    • Journal of Gifted/Talented Education
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    • v.23 no.4
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    • pp.593-614
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    • 2013
  • The purpose of this study was to analyze the research ethics elementary and secondary gifted students enrolled in science-gifted education center of university and to get the implications of research ethics education. 180 elementary and secondary gifted students and 180 general students were participated. The results obtained from this study were as follows: First, the item, such as 'The researchers must have self-esteem and responsibility in their study', both the gifted students and the general students showed the highest perception. On the contrary, the item 'I think that it is right to exclude the person who didn't participate in research' both the gifted students and the general students showed the lowest perception. And gifted students' perception on research ethics was higher than the general students' on the whole. There was a statistically significant difference between two groups(p<.05). Second, the scientifically gifted students' research ethics in 'basic attitude of the researchers' was significantly higher than mathematically gifted students' and IT gifted students' (p<.05). Third, there was a statistically significant difference between the elementary gifted students and secondary gifted students in 'ethics of thought and expression' (p<.05). Fourth, experience in research ethics education and the number of research experience was significantly effect on perception of research ethics. There was a statistically significant interaction effect between gifted students and general students in 'science, technology, biomedical research ethics' items(p<.05).

Performance Evaluation to Develop an Engineering Scale Cathode Processor by Multiphase Numerical Analysis (다상유동 전산모사를 통한 공학 규모의 cathode processor의 성능평가)

  • Yoo, Bung Uk;Park, Sung Bin;Kwon, Sang Woon;Kim, Jeong Guck;Lee, Han Soo;Kim, In Tae;Lee, Jong Hyeon
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.12 no.1
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    • pp.7-17
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    • 2014
  • Molten salt electrorefining process achieves uranium deposits at cathode using an electrochemical processing of spent nuclear fuel. In order to recover pure uranium from cathode deposit containing about 30wt% salt, the adhered salt should be removed by cathode process (CP). The CP has been regarded as one of the bottle-neck of the pyroprocess as the large amount of uranium is treated in this step and the operation parameters are crucial to determine the final purity of the product. Currently, related research activities are mainly based on experiments consequently it is hard to observe processing variables such as temperature, pressure and salt gas behavior during the operation of the cathode process. Hence, in this study operation procedure of cathode process is numerically described by using appropriate mathematical model. The key parameters of this research are the amount of evaporation at the distillation part, diffusion coefficient of gas phase salt in cathode processor and phase change rate at condensation part. Each of these conditions were composed by Hertz-Langmuir equation, Chapman-Enskog theory, and interphase mass flow application in ANSYS-CFX. And physical properties of salt were taken from the data base in HSC Chemistry. In this study, calculation results on the salt gas behavior and optimal operating condition are discussed. The numerical analysis results could be used to closely understand the physical phenomenon during CP and for further scale up to commercial level.

Economic Injury Levels of Spoladea recurvalis on Beet in the Plastic Greenhouse (비트 흰띠명나방의 경제적 피해수준 설정)

  • Kim, Ju;Choi, In-Young;Lee, Sang-Koo;Lim, Ju-Rak;Lee, Jang-Ho;Cheong, Seong-Soo;Lee, Sang-Guei
    • The Korean Journal of Pesticide Science
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    • v.18 no.3
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    • pp.175-180
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    • 2014
  • This study was carried out to determine the economic injury level and economic threshold level on beet (Beta vulgaris L.) infested with Spoladea recurvalis in the plastic greenhouse condition in 2010. The second instar larvae of S. recurvalis were inoculated with 7 different density levels on the each 10 beet plants as a replication. Injury levels of beet leaves and density of S. recurvalis were increased with the inoculation density of S. recurvalis. However, yield and marketable commodity of beet were decreased. Linear relationship between the percent yield reduction (Y) of beet leaves and different infestation densities of S. recurvalis (X) was estimated by the following equation Y = 1.226x + 3.36. Based on the relationships between the densities of S. recurvalis larvae and yield index of beet leaves, the number of second instar larvae which caused 5% loss of yield, economic threshold level was estimated as 1.1 larvae/10 plants for the planting 10 days. The percent yield reduction (Y) of beet roots infested with different densities of S. recurvalis (X) estimated by the following equation Y = 1.537x + 1.4634 after inoculation for 10 days at 3rd harvesting of leaves. Based on the relationships between the densities of S. recurvalis larvae and yield index of beet roots, the number of second instar larvae which caused 5% loss of yield, economic threshold level was estimated as 6.4 larvae/10 plants for the planting 10 days.

Optimi Design for R.C. Beam with Discrete Variables (이산형 설계변수를 갖는 철그콘크리트보의 최적설계)

  • 구봉근;한상훈;김홍룡
    • Magazine of the Korea Concrete Institute
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    • v.5 no.4
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    • pp.167-178
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    • 1993
  • The objective of this paper is to look into the possibility of the detailed and practical optimum design of rt:inforced concrete beam using methods oi discrete mathematical programming. In this discrete optimum formulation, the design variables are the overall depth, width and effective depth of members, and area of longitudinal reinforcement. In addition, the details such as the amount of web reinforcement and cutoff points of longitudinal reinforcement are also considered as variables. Total cost has been used as the objective function. The constraints include the code requirments such as flexural strength, shear strength, ductility, serviceability, concrete cover. spacing, web reinforcement, and development length and cutoff points of longitudinal renforcement. An optimization algorithm is presented for effective optimum design of R.C. beam with discrete de sign variables. First, the continuous variable optimization can be achieved by Feasible Direction Method. Using the results obtained from the continuous variable optimization, a branch and bound method is used to obtained the discrete design values. The proposed algorithm is applied to test problem for reliability, and the results are compared with those of graphical method and rounded-up method. And a simply supported R.C. beam and a two-span continuous R.C. beam are presented as numerical examples for effectiveness and applicability. It is considered that the presented algorithm can be effectively applied to the discrete optimum design of R.C. beams.

An Analysis of Dynamic Characteristics of RDX Combustion Using Rigorous Modeling (상세 모델링을 통한 RDX 연소 동특성 분석)

  • Kim, Shin-Hyuk;Yeom, Gi-Hwoen;Moon, Il;Chae, Joo-Seung;Kim, Hyeon-Soo;Oh, Min
    • Clean Technology
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    • v.20 no.4
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    • pp.398-405
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    • 2014
  • In the treatment of spent high energetic materials, the issues such as environmental pollution, safety as well as working capacity should be carefully considered and well examined. In this regard, incineration has been recommended as one of the most promising processes for the disposal of such explosives. Due to the fact that high energetic materials encompass various types and their different characteristics, the technology development dealing with various materials is not an easy task. In this study, rigorous modeling and dynamic simulation was carried out to predict dynamic physico-chemical phenomena for research department explosive (RDX). Plug flow reactor was employed to describe the incinerator with 263 elementary reactions and 43 chemical species. Simulation results showed that safe operations can be achieved mainly by controlling the reactor temperature. At 1,200 K, only thermal decomposition (combustion) occurred, whereas increasing temperature to 1,300 K, caused the reaction rates to increase drastically, which led to ignition. The temperature further increased to 3,000 K which was the maximum temperature recorded for the entire process. Case studies for different operating temperatures were also executed and it was concluded that the modeling approach and simulation results will serve as a basis for the effective design and operation of RDX incinerator.

The Analysis of Forest Successional Trend by Species Replacement Model in the Natural Forest (천연림의 수종 대치 작용 모델에 의한 산림천이 경향 분석)

  • 김지홍
    • Journal of Korea Foresty Energy
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    • v.22 no.3
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    • pp.1-10
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    • 2003
  • The successional status and potential natural vegetation were examined in the natural deciduous forest in Mt. Chombong area. The examination was based on the subsequent process of generation replacement by understory saplings for the dominant canopy trees within 106 20mx20m square sample plots. The transition matrix model, which was modified from mathematical theory of Markov chain, was employed to analyze the successional status of the study forest. The model suggests that study forest is still seral, and it is considered to be more than 500 years away from the steady state or climax in terms of species composition. The simulations predict a remarkable decrease in the proportion of species composition of the present dominant Quercus mongolica and Kalopanax pictus from current 42.6% and 8.1% to less than 13.3% and 0.5%, respectively, at the steady state. On the contrary, the proportions of Abies holophylla, Acer mono, Fraxinus mandshurica, Tilia amurensis, and Acer pseudo-sieboldianum will increase at the steady state. The change of predicted composition ratio was generally coincide with the result of tolerance index to be compared with the study model. The hypothesis and sensitivity of the model were also discussed to evaluate the applicability to the real situation. The overall results indicated that the present dynamics of the forest must reflect the seral state due to previous disturbance mainly by human related interference.

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The Comparison of Perceptions of Science-related Career Between General and Science Gifted Middle School Students using Semantic Network Analysis (과학영재 중학생들과 일반 중학생들의 과학과 관련된 직업에 대한 인식 비교: 언어 네트워크 분석법 중심으로)

  • Shin, Sein;Lee, Jun-Ki;Ha, Minsu;Lee, Tae-Kyong;Jung, Young-Hee
    • Journal of Gifted/Talented Education
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    • v.25 no.5
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    • pp.673-696
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    • 2015
  • Students' perception of science-related career strongly influences the formation of career motivation in science. Especially, the high level of science gifted students' positive perceptions plays an important role in allowing them to continue to study science. This study compared perceptions of science-related career between general and gifted middle school students using semantic network analysis. To ensure this end, we first structuralize semantic networks of science-related careers that students perceived. Then, we identified the characters of networks that two different student groups showed based on the structure matrix indices of semantic network analysis. The findings illustrated that the number of science-related careers shown in science gifted students' answer is more than in general students' answer. In addition, the science gifted students perceived more diverse science-related careers than general students. Second, scientific career such as natural scientists and professors were shown in the core of science gifted students' perception network whereas non-research oriented careers such as science teachers and doctors were shown in the core of general students' perception network. In this study, we identified the science gifted students' perceptions of science-related career was significantly different from the general students'. The findings of current study can be used for the science teachers to advise science gifted students on science-related careers.

A Study on the Development and Effect of Korean Language Education Program Based on Multiple Intelligences (다중지능에 기초한 국어교육 프로그램 개발 및 효과검증)

  • Ku, Ji-Hye;Park, Seong-Ok
    • Journal of Gifted/Talented Education
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    • v.19 no.1
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    • pp.69-94
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    • 2009
  • The purpose of this study was to develop and apply a Korean language education program based on multiple intelligences in a bid to foster the multiple intelligences, self-efficacy and achievement motivation of elementary schoolers in regular language arts class. It's basically meant to create the educational conditions for every child to exert his or her abilities. Two research questions were posed: 1. What should be the objectives, content and teaching-learning methods of a Korean language education program based on multiple intelligences? 2. What effect does a Korean education program based on multiple intelligences have on children's multiple intelligences, self-efficacy and achievement motivation? The subjects in this study were 58 Students in two different third-grade classes in M elementary school in the city of Daejeon. A Korean language education program based on multiple intelligences was implemented during a 4month period of time, and an inclusive approach of multiple intelligences and cooperative learning were applied. The major findings of the study were as follows: First, in order to develop a Korean education program based on multiple intelligences, the kinds of themes that could cover multiple intelligences in an inclusive way were selected in consideration of the learning objectives of the major units of a third-grade language arts textbook(second semester) of the 7th national elementary language arts curriculum. And then an inclusive Korean education program was prepared, which consisted of four stages: problem awareness, problem-solving planning, problem solving, and reflection/application/development. Second, the Korean education program based on multiple intelligences had a positive effect on the children's multiple intelligences, self-efficacy and achievement motivation and suggested some of new directions for school education that typically stressed linguistic and logical-mathematical intelligences only.

Design and Validation of Education Contents of Algorithm for the Gifted Elementary Students of Computer Science (초등정보과학영재를 위한 알고리즘 교육내용의 설계 및 검증)

  • Lee, Jae-Ho;Oh, Hyeon-Jong
    • Journal of Gifted/Talented Education
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    • v.19 no.2
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    • pp.353-380
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    • 2009
  • The significant reason for studying computer science lies in the efficient resolution of various problems which can arise in actual life. Consequently, algorithm education is very important in the computer science and plays a great part in helping to enhance the creative ability to solve problems and to improve the programming ability. However, the current algorithm education at an computer science educational institute for the gifted has inadequate systematic quality and is only treated as a part of programming education. From this perspective, this paper carried out following studies in order to design the algorithm education for elementary computer science prodigies. First, the core educational contents was selected by extracting the common elements from existing books related to algorithm education, common study contents on algorithm lesson websites and the study area of ACM's computer algorithm. Second, using the development criteria and selected educational contents, the educational theme for the If weeks load was set. Additionally, the algorithm educational contents were designed for the elementary computer science prodigy based on such theme. Third, the activity site for the use of prodigy educational institute was developed with the background in the educational contents for the elementary computer science prodigy. Fourth, the Delphi analysis technique was used to verify the appropriateness of contents and activity site developed in this paper. It was carried out in 2 separate processes where the first process verified the design of educational contents, and the second process verified the appropriateness of developed activity site.

Modeling of the Charge-discharge Behavior of a 12-V Automotive Lead-acid Battery (차량용 12-V 납축전지의 충·방전 모델링)

  • Kim, Ui Seong;Jeon, Sehoon;Jeon, Wonjin;Shin, Chee Burm;Chung, Seung Myun;Kim, Sung Tae
    • Korean Chemical Engineering Research
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    • v.45 no.3
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    • pp.242-248
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    • 2007
  • For an optimal design of automotive electric system, it is important to have a reliable modeling tool to predict the charge-discharge behaviors of the automotive battery. In this work, a two-dimensional modeling was carried out to predict the charge-discharge behaviors of a 12-V automotive lead-acid battery. The model accounted for electrochemical kinetics and ionic mass transfer in a battery cell. In order to validate the modeling, modeling results were compared with the experimental data of the charge-discharge behaviors of a lead-acid battery. The discharge behaviors were measured with three different discharge rates of C/5, C/10, and C/20 at operating temperature of $25^{\circ}C$. The batteries were charged with constant current of 30A until the charging voltage reached to a predetermined value of 14.24 V and then the charging voltage was kept constant. The discharge and charge curves from the measurements and modeling were in good agreement. Based on the modeling, the distributions of the electrical potentials of the solid and solution phases, the porosity of the electrodes, and the current density within the electrodes as well as the acid concentration can be predicted as a function of charge and discharge time.