• Title/Summary/Keyword: 개념적 연구

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Analysis of Precipitate Formation Reaction for Measuring Chemical Reaction Rate and Its Development Appling Small-Scale Chemistry (앙금 생성 반응을 이용한 화학반응속도 측정 실험의 분석과 Small-Scale Chemistry를 적용한 실험 개발)

  • Park, Kuk-Tae;Noh, Ji-Hyun;Kim, Dong-Jin;Ryu, Ran-Yeong;Noh, Yun-Mi;Kim, Myo-Kyung;Lee, Sang Kwon
    • Journal of the Korean Chemical Society
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    • v.52 no.3
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    • pp.303-314
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    • 2008
  • The purpose of this study was to understand the experiment for measuring chemical reaction rate by precipitate formation and to develop experiments applying small-scale chemistry. For this study, the experimental method for measuring the effect of concentration and temperature on chemical reaction rates presented in the 10 high school science textbooks were classified by their experimental methods of confirming production. Subsequently, problems observed in carrying out the experiments for measuring chemical reaction rates by precipitate formation frequently presented in the 10 high school science textbooks were analyzed. Experiments applying small-scale chemistry were developed measuring chemical reaction rate by precipitate formation. According to the result of this study, there were some problems in the experimental method of precipitate formation for measuring chemical reaction rates presented in the high school science textbooks. Those problems in the science textbook experiments were insufficient specification of mixing methods of reaction solutions, obscurity of knowing when the character letter X disappeared, time delay in collecting the experimental data, formation of hazardous sulfur dioxide, uneasiness of fixing water bath container, controlling the reaction temperature, and low reproducibility. Those problems were solved by developing experiments applying smallscale chemistry. Presenting the procedure of mixing reaction solutions on the A4 reaction paper sheet made the experimental procedure clearly, using well plates and stem pipette shortened the reaction time and made it possible to continuously collect the experimental data. Furthermore, the quantity of hazardous sulfur dioxide was reduced 1/7 times and the time when the character letter X disappeared could be observed clearly. Since experiments for measuring the effect of concentration and temperature on chemical reaction rates could be performed in 30 minutes, the developing experiments applying SSC would help students understand the scientific concepts on the effect of concentration and temperature on chemical reaction rates with enough time for experimental data analysis and discussion.

Content Validity of and Information from Elementary Students' Science Portfolio Assessment (초등학교 과학과 포트폴리오 평가의 내용 타당도 검증 및 학생 포트폴리오에서 파악할 수 있는 정보의 유형)

  • Kim, Chan-Jong;Yoon, Sun-Ah
    • Journal of The Korean Association For Science Education
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    • v.22 no.1
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    • pp.190-203
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    • 2002
  • The purpose of this study is to test content validity of a portfolio assessment and to analyse the information which can be obtained from student portfolios. The content validity of the portfolio was tested against the objectives of each lesson and the emphasis of curriculum. The information was identified from the analysis of student portfolios. Students' portfolios from a fourth grade class in Pyeungteak, Kyeungki-do were used for analysis. The portfolios included students' evidence of learning on (I) Strata, Unit 2 'Strata and Fossil,' and (3) Change of Object by Heat, Unit 4 'Heat and Change of Object'. Fourth-grade science textbooks were also analyzed to understand the base level information for portfolio analysis. Two science education specialists and ten elementary teachers majored in science education took part in this analysis. The results of the analysis showed $70{\sim}100%$ of agreement between the objectives of lesson and portfolio forms. Over 90% of agreement is reached between portfolio forms and the emphasis of the curriculum. Student portfolios revealed much information on comprehension, observation, will to study, and process of learning. They also revealed some information on drawing conclusion, communication. self-direction, progress of learning, self-concept, interaction, and process of learning. As a whole, the information in students' portfolios is similar with that dealt in science textbooks. However, students' portfolios have more information on anticipation, will to study, self-direction, and interaction. On the contrary, science textbook deals more with information on observation, planning inquiry, than students' portfolios. The portfolio assessment examined has very sound content validity. The results also show that much more and various information which can not be obtained from pencil and paper test could be obtained from student portfolios. The use of information, obtained from student portfolios will make it possible understand students' learning. their strength and weakness, hence improve student' science learning.

An Inquiry into the Meaning of "Sasang" in the I Ching and Its Relationship to the Sasang Medicine (주역의 '사상'과 사상의학의 '사상'의 연관성에 관한 고찰)

  • Lee, Sung-hwan;Kim, Ki-hyon
    • Journal of Sasang Constitutional Medicine
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    • v.12 no.1
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    • pp.24-36
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    • 2000
  • Purpose : Many believe that the Sasang mentioned in the I Ching and the Sasang of Sasang Medicine (as expounded by Dr. Lee Je-ma in the book Longevity and Life Preservation in Oriental Medicine) refer to different concepts. This is untrue. In order to understand the thought patterns of Dr. Lee Je-ma and his book, it is necessary to first understand the concepts of the I Ching. The I Ching was the most respected text in Dr. Lee Je-ma time, and served as the foundation upon which his medicine stood. The purpose of this research is to understand the concept of Sasang in the I Ching and how it applies to the Sasang medicine. Method : The authors first defined the term Sasang according to the theory of I Ching. It was then discussed in relation to theories of modern science. Inferences were made as to how Sasang corresponds to the terminologies and concepts of modern science. The characteristics of Sasang interpreted through modern science were then applied to the physiology, pathology and pharmacology of Sasang Medicine. Results and Conclusion : 1. The Sasang theory of the I Ching organizes seemingly random and isolated natural phenomena into four distinct groups according to various attributes. The particular characteristics representing each of these four categories are known as Sasang. 2. The Sasang theory of I Ching has a strong correlation to the Theory of Relativity and the Theory of Complementarity, as well as the Digital and Fractal Theories. 3. By applying the Sasang Theory to various fields, the seemingly unrelated principles of physics, chemistry, biology and medicine can be seen as parts of a whole. 4. Sasang Medicine categorizes human morphology, physiology and pharmacology into four categories according to the characteristics defined by the Sasang Theory of the I Ching. 5. Grouping new discoveries of modern physics, chemistry, biology and medicine according to the Sasang Theory will bring to light the intricacies of the Sasang Theory while facilitating the incorporation of modern science into Sasang Medicine.

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Analysis on the Influence of Moment Distribution Shape on the Effective Moment of Inertia of Simply Supported Reinforced Concrete Beams (철근콘크리트 단순보의 유효 단면2차모멘트에 대한 모멘트 분포 형상의 영향 분석)

  • Park, Mi-Young;Kim, Sang-Sik;Lee, Seung-Bae;Kim, Chang-Hyuk;Kim, Kang-Su
    • Journal of the Korea Concrete Institute
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    • v.21 no.1
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    • pp.93-103
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    • 2009
  • The concept of the effective moment of inertia has been generally used for the deflection estimation of reinforced concrete flexural members. The KCI design code adopted Branson's equation for simple calculation of deflection, in which a representative value of the effective moment of inertia is used for the whole length of a member. However, the code equation for the effective moment of inertia was formulated based on the results of beam tests subjected to uniformly distributed loads, which may not effectively account for those of members under different loading conditions. Therefore, this study aimed to verify the influences of moment shapes resulting from different loading patterns by experiments. Six beams were fabricated and tested in this study, where primary variables were concrete compressive strengths and loading distances from supports, and test results were compared to the code equation and other existing approaches. A method utilizing variational analysis for the deflection estimation has been also proposed, which accounts for the influences of moment shapes to the effective moment of inertia. The test results indicated that the effective moment of inertia was somewhat influenced by the moment shape, and that this influence of moment shape to the effective moment of inertia was not captured by the code equation. Compared to the code equation, the proposed method had smaller variation in the ratios of the test results to the estimated values of beam deflections. Therefore, the proposed method is considered to be a good approach to take into account the influence of moment shape for the estimation of beam deflection, however, the differences between test results and estimated deflections show that more researches are still required to improve its accuracy by modifying the shape function of deflection.

Analysis of Slope Stability Considering the Saturation Depth Ratio by Rainfall Infiltration in Unsaturated Soil (불포화토 내 강우침투에 따른 포화깊이비를 고려한 사면안정해석)

  • Chae, Byung-Gon;Park, Kyu-Bo;Park, Hyuck-Jin;Choi, Jung-Hae;Kim, Man-Il
    • The Journal of Engineering Geology
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    • v.22 no.3
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    • pp.343-351
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    • 2012
  • This study proposes a modified equation to calculate the factor of safety for an infinite slope considering the saturation depth ratio as a new variable calculated from rainfall infiltration into unsaturated soil. For the proposed equation, this study introduces the concepts of the saturation depth ratio and subsurface flow depth. Analysis of the factor of safety for an infinite slope is conducted by the sequential calculation of the effective upslope contributing area, subsurface flow depth, and the saturation depth ratio based on quasi-dynamic wetness index theory. The calculation process makes it possible to understand changes in the factor of safety and the infiltration behavior of individual rainfall events. This study analyzes stability changes in an infinite slope, considering the saturation depth ratio of soil, based on the proposed equation and the results of soil column tests performed by Park et al. (2011 a). The analysis results show that changes in the factor of safety are dependent on the saturation depth ratio, which reflects the rainfall infiltration into unsaturated weathered gneiss soil. Under continuous rainfall with intensities of 20 and 50 mm/h, the time taken for the factor of safety to decrease to less than 1.3 was 2.86-5.38 hours and 1.34-2.92 hours, respectively; in the case of repeated rainfall events, the time taken was between 3.27 and 5.61 hours. The results demonstrate that it is possible to understand changes in the factor of safety for an infinite slope dependent on the saturation depth ratio.

A Study on the Improvement of the Existing Technology Valuation Solutions;focused on high technology based start-up company (현행 기술가치 평가모형의 개선 방안에 관한 연구;신기술 창업기업의 경우를 중심으로)

  • Yang, Tai-Shik;Min, Kyung-Se
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.2 no.2
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    • pp.93-120
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    • 2007
  • To promote the commercialization of high technology based start-up company, it is essential to activate technology trading for the Innovative Small & Medium companies which eager to acquire technology competitiveness through technology trading and facilitate financial system which provide Small & Medium companies with technology commercialization money. This study focus on enhancing credibility of technology valuation solutions through the improvement of the existing technology valuation solutions. The existing technology valuation solutions in practice have deficiency in reasonable valuation because of subjective technology factor's calculation. And the commercialization risk of high technology based start-up companies cannot be fully reflected in the existing valuation solutions. The high risk of technology commercialization acts as a hurdle in the facilitation of providing money for the start-up companies. The improved new model will have more acceptable objectivity and reasonably reflect the commercialization risk of start-up companies. The new model has two distinctive features compared to existing solutions. The new model newly adopts commercialization success factor which reflects the risk of high technology based start-up company. And the new model excludes technology factor which is controversial among interested parties. The exclusion of technology factor will improve the objectivity of technology valuation and the adoption of commercialization success factor will solicit investor and capitalist who concern the high risk of technology based start-up companies. In conclusion, the improved new model is expected to activate technology trading and facilitate the money market through which high technology based start-up companies raise commercialization money.

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Analysis on the Use Characteristics of Citizen based on Urban Green Spaces Type - Focuses on Suwon-City - (도시녹지 유형에 따른 도시민의 이용 특성 연구 - 수원시를 대상으로 -)

  • Kim, Yea Sung;Kim, Hyun;Ko, Jinsoo
    • Journal of the Korean Institute of Landscape Architecture
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    • v.42 no.5
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    • pp.31-40
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    • 2014
  • The importance of green spaces in the city is growing each day. Local governments are taking charge of park development works that are having difficulty in developing and managing urban parks due to high land value as well as a shortage in finances. This is even though an urban park is defined as an urban planning facility and the law provides park area per person. Civil residents, meanwhile, are using not only urban parks provided by law but also other green areas such as rivers, reservoirs, and school playgrounds because they recognize urban green areas by the concept of use. In this study, accordingly, urban green areas were sorted into two types, urban parks, parks provided by law, and other green areas, and the difference in use pattern and use satisfaction by type was analyzed. As a result of analysis, there was no remarkable difference between the two types. According to such results, it was found that it is necessary to include other green areas, such as rivers, reservoirs, school green areas, and apartment green areas in addition to the current park green areas provided by law when park area per person is calculated, and such calculation of urban green areas reflecting local characteristics can reduce local governments' financial burden and improve the effectiveness of future urban park policies. It is judged that such results can become a plan against the cancellation of unexecuted urban facilities. The fact that accessibility factors, such as road satisfaction, access convenience, and convenient movement, are affecting satisfaction with the use of urban parks suggests that it is important to improve urban park accessibilities rather than to quantitatively expand park area in order to improve satisfaction with urban parks. Considering that people travel to urban green areas mostly by walking, it is necessary for access convenience to conduct follow-up studies such as barrier-free and securing walking stability through analysis of routes to urban green areas.

An Empirical Study on the Effects of Category Tactics on Sales Performance in Category Management - A Comparative Study by Store Type and Market Position - (카테고리 매출성과에 영향을 미치는 카테고리 관리 전술들에 대한 실증연구 - 점포유형과 시장포지션에 따른 비교분석 -)

  • Chun, Dal-Young
    • Journal of Distribution Research
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    • v.12 no.3
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    • pp.23-48
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    • 2007
  • Category management has been implemented to enhance competitiveness in the food distribution industry since 2000 in Korea. This study helps to understand why suppliers achieve better or worse performance than competitors in a category. The major objective of this article is to explore which category tactics are effective to have influence on category performance when suppliers as a category captain implement category management with variety enhancer categories like shampoo, toothpaste, and detergent. The Nielsen data were analyzed using regression and Chow test. The empirical results that were varied upon the store type and market position found out which specific actions on product assortments, pricing, shelving, and product replenishment can increase category sales. Specifically, in the case of market leader in large supermarket, the significant indicators of category sales with respect to category tactics are the out-of-stock rate, the variance across brand shares, the forward inventory, and the days supply of a product. However, in the case of follower in large supermarket, the significant indicators of category sales are the variance across brand shares, the forward inventory, and the days supply of a product. On the other hand, in the case of small supermarket, the significant factors on category sales for both market leader and follower are the retail distribution rate, the variance across brand shares, the forward inventory, and the days supply of a product category. In sum, regardless of the store type and market position, dominant brands in a category, the forward inventory, and short days supply of a product improved performance in all categories. Critical difference is that the out-of-stock rate acted as a key ingredient for the market leader between large and small supermarket and the retail distribution rate for the follower between large and small supermarket. This article presents some theoretical and managerial implications of the empirical results and finalizes the paper by addressing limitations and future research directions.

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Development of Teaching-Learning Plans Applying ARCS Motivation Strategies for Food Safety Education (ARCS 동기유발 전략을 적용한 식품 안전 교육 교수·학습 과정안 개발)

  • Kim, Yewon;Yu, Nan Sook;Lee, Gyeongsuk
    • Journal of Korean Home Economics Education Association
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    • v.31 no.3
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    • pp.135-153
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    • 2019
  • The purpose of this study was to develop teaching-learning plans applying ARCS strategies for food safety education, focusing on units related to the 'food selection and safe cooking'. To achieve this purpose, this study was conducted in the following order of analysis, design, development, assessment I, revision I, assessment II, revision II, and completion. In the analysis stage, 2015 revised curriculum and middle school technology-home economics textbooks(12 kinds) contents of 'food selection and safe cooking' among content elements of core concept 'safety' were analyzed. In the design and development stages, teaching-learning plans, teaching-learning materials, and evaluation rubric for teaching-learning outcomes using the ARCS motivation strategy were developed. In the phases of assessment I and revision I, evaluation items were selected as open-ended questions about food safety education factors and ARCS strategies, and their validities were verified by four experts. The teaching-learning plans for nine lessons were revised based on the feedbacks such as evaluation plans considering the correspondence between instruction and evaluation, strategy to reinforce intrinsic motivation, correction of improper contents composition, and so on. In the phases of assessment II and revision II, the validity of the three items, including relevance of each teaching-learning to food safety education, suitability of learning goals, and appropriateness of motivation strategy, was verified by seven experts. The final teaching-learning plans for 10 lessons were developed by revising and supplementing the data by compiling opinions of the assessment II. It is expected that this study can contribute to food safety education for middle school students, and that teaching-learning plans which apply ARCS strategies for food safety education will be used as good references for school teachers and curriculum developers.

Ecoclimatic Map over North-East Asia Using SPOT/VEGETATION 10-day Synthesis Data (SPOT/VEGETATION NDVI 자료를 이용한 동북아시아의 생태기후지도)

  • Park Youn-Young;Han Kyung-Soo
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.8 no.2
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    • pp.86-96
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    • 2006
  • Ecoclimap-1, a new complete surface parameter global database at a 1-km resolution, was previously presented. It is intended to be used to initialize the soil-vegetation- atmosphere transfer schemes in meteorological and climate models. Surface parameters in the Ecoclimap-1 database are provided in the form of a per-class value by an ecoclimatic base map from a simple merging of land cover and climate maps. The principal objective of this ecoclimatic map is to consider intra-class variability of life cycle that the usual land cover map cannot describe. Although the ecoclimatic map considering land cover and climate is used, the intra-class variability was still too high inside some classes. In this study, a new strategy is defined; the idea is to use the information contained in S10 NDVI SPOT/VEGETATION profiles to split a land cover into more homogeneous sub-classes. This utilizes an intra-class unsupervised sub-clustering methodology instead of simple merging. This study was performed to provide a new ecolimatic map over Northeast Asia in the framework of Ecoclimap-2 global database construction for surface parameters. We used the University of Maryland's 1km Global Land Cover Database (UMD) and a climate map to determine the initial number of clusters for intra-class sub-clustering. An unsupervised classification process using six years of NDVI profiles allows the discrimination of different behavior for each land cover class. We checked the spatial coherence of the classes and, if necessary, carried out an aggregation step of the clusters having a similar NDVI time series profile. From the mapping system, 29 ecosystems resulted for the study area. In terms of climate-related studies, this new ecosystem map may be useful as a base map to construct an Ecoclimap-2 database and to improve the surface climatology quality in the climate model.