• 대한화학회지
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• 제62권3호
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• pp.243-252
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• 2018

이 연구에서는 중학교 2학년 학생들의 물질의 특성에 대한 거시적, 미시적 수준의 개념을 비교하였다. 기초 입자 개념 검사와 녹는점, 용해도, 밀도 개념에 대한 거시적, 미시적 수준의 개념 검사를 개발하여 371명의 중학생들을 대상으로 실시하였다. 학생들의 응답을 거시적 수준과 미시적 수준의 개념 이해 여부에 따라 네 가지로 범주화하고 범주별 비율과 특징을 분석하였다. 연구 결과, 거시적 수준의 개념을 이해한 학생들은 미시적 수준에서 다양한 오개념을 가지고 있는 경우가 많았다. 많은 학생들은 물질의 특성과 관련한 미시적 수준의 개념뿐 아니라 거시적 수준의 개념 이해에도 어려움을 겪었다. 거시적 수준의 개념을 이해하지 못한 학생들은 대부분 미시적 수준에서 거시적 수준의 응답과 일치하는 응답을 하지 못하였다. 기초 입자 개념 문항에 옳은 응답을 한 학생들도 물질의 특성 관련 개념을 이해하는 데 어려움을 겪었으나, 거시적 수준의 개념을 이해한 경우 미시적 수준의 개념도 함께 이해한 비율이 높았다. 연구 결과를 바탕으로 물질의 특성 관련 개념의 효과적인 교수학습 및 향후 교육과정의 개선을 위한 교육적 시사점을 논의하였다.

• 대한수학교육학회지:수학교육학연구
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• 제11권1호
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• pp.1-10
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• 2001

Most existing research into the metacognitive approach in mathematics learning has been concentrated mainly in the study of phenomena of metacognitive (including the affective) behaviour in the context of mathematical problem solving or more broadly mathematical content-elated learning. However, this study originally constructs the concept of "macroscopic metacognition" which could be differentiated with general metacognition, and draws out macroscopic-metacognitive factors among the elementary and middle school students through individual interview. Questionnaire research is executed to find out how the macroscopic metacognition is included into the students' mathematics learning and the relationship between their mathematics learning accomplishment and macroscopic metacognition. Thus, a considerable degree of the positive relationship between these two variables was found out.

• 한국결정학회지
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• 제11권3호
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• pp.157-161
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• 2000

In a 200nm Cz-Si crystal, a macroscopic fluctuation in pulling rate was intentionally introduced an then the variations of the pulling rate and the position of OSF-ring were compared each other. The formation behavior of OSF-ring in the effective volume, defined as the region between the growth interface position -α and the growth interface position +α, is most affected by the pulling rate fluctuation. To understand the correct effect of a macroscopic pulling rate fluctuation, its cumulative effect in the effective volume should be considered. A new concept of modeling for it was proposed here.

• 문화기술의 융합
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• 제7권3호
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• pp.303-310
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• 2021

거시적 데이터 변화를 단순한 형태로 유추 비교 및 분석하는 시각 정보 콘셉트 개발방법이 필요하다. 시각 정보 콘셉트의 개발에는 시각화 형태 선택, 수사학적 효과 선택 그리고 디지털 표현요소 선택 작업이 필요한데, 이 중에서, 사용자에게 시각 정보를 효과적으로 전달하기 위한 수사학적 효과 선택 방법의 예를 제시한다. 본 연구에서는 기간별 및 업종별 주가 분석을 위해서, 원관념과 비유되는 보조관념을 통하여 거시적 관점에서 데이터 비교 분석이 가능한 메타포 수사학을 선택했다. 갓털이 퍼져나가는 민들레를 메타포로 사용한 2차원 3단 형태 변화와 시간에 변화 따라서 형태와 색상이 변하는 코랄 작약 꽃송이를 메타포로 사용한 3차원의 3단 형태 변화 정보표현 방식을 제시한다. 이러한 수사학적 메타포를 사용하면, 거시적인 거래 변화와 업종별 주가 비교 분석이 가능하다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권11호
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• pp.4483-4501
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• 2020

Recent findings identified the scatter and shape of MFD (macroscopic fundamental diagram) is heavily influenced by the spatial distribution of link density in a road network. This implies that the concept of MFD can be utilized to divide a heterogeneous road network with different degrees of congestion into multiple homogeneous subnetworks. Considering the actual traffic data is usually incomplete and inaccurate while most traffic partition algorithms rely on the completeness of the data, we proposed a three-step partitioned algorithm called Iso-MB (Isoperimetric algorithm - Merging - Boundary adjustment) permitting of incompletely input data in this paper. The proposed algorithm was implemented and verified in a simulated urban transportation network. The existence of well-defined MFD in each subnetwork was revealed and discussed and the selection of stop parameter in the isoperimetric algorithm was explained and dissected. The effectiveness of the approach to the missing input data was also demonstrated and elaborated.

• 한국과학교육학회지
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• 제25권7호
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• pp.773-786
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• 2005

이 연구에서는 개발한 설문지를 통해 공기 중의 수증기량이 증발과 끓음에 미치는 영향에 대한 고등학생과 화학 전공 교사들의 인식을 조사하였다. 교과서의 서술에서 증발과 끓음은 기화라는 개념으로 연결되어 제시되고, 끓음은 증기압과 대기압의 관계로 설명되며, 증기압은 증발로 형성된 공기 중의 수증기 개념으로 연결되어 제시되어 있다. 이러한 개념간의 연결 사이에서 일어나는 다양한 인식들을 고등학생들의 경우와 화학 전공 교사들의 경우로 구분하여 비교하여 보았다. 또한 다양한 인식들이 형성된 배경을 알아보기 위하여 교과서의 관련 내용을 분석하였다. 연구 결과, 많은 학생들이 공기 중의 수증기량과 증발 및 끓음은 관련이 있다고 생각하였다. 그러나 이들은 거시적인 수준에서 설명되는 증발 현상과 미시적인 수준에서 이루어지는 물 입자들의 증발을 구분하지 못하였다. 또한 공기 중의 수증기가 증기압과 끓음에도 영향을 미친다고 생각하였다. 교사들의 경우에는 과학적 개념의 형성 비율이 학생들보다 높았으나, 많은 교사들이 학생들과 유사하게 증발과 끓음에 대해 다양한 인식을 하고 있었다. 교과서에서는 보편적으로 거시적인 관점에서 증발과 끓음의 현상을 설명하였으며, 미시적인 관점을 제시하는 경우에도 개념들간의 연결이 제대로 이루어지지 않았다.

• Structural Engineering and Mechanics
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• 제16권4호
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• pp.371-390
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• 2003

The concept of the seismic slit shear wall was proposed in the early 1990's. A series of experimental and theoretic studies on the wall with reinforced concrete short connecting beams cast in the slit were carried out. In this paper another type of slit shear wall is studied. It is one with vertical slit purposely cast within the wall, and the rubber belt penetrated by a part of web shear reinforcement as seismic energy-dissipation device is filled in the slit. Firstly, an experiment under cyclic loading was carried out on two shear wall models, one slit and the other solid. The failure mechanism and energy-dissipation capacity are compared between the two different models, which testifies the seismic performance of the slit wall improved significantly. Secondly, for engineering practice purpose, a macroscopic analytical model is developed to predict the nonlinear behavior of the slit shear wall under cyclic loading. The mechanical properties of each constituent elements of this model are based on the actual behavior of the materials. Furthermore, the effects of both the axial force and bending moment on the shear behavior are taken into account with the aid of the modified compression-field theory. The numerical results are verified to be in close agreement with the experimental measurements.

• 한국안전학회지
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• 제33권4호
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• pp.98-104
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• 2018

Macroscopic accident analyses have been conducted to incorporate transportation safety into long-term transportation planning. In macro-level accident prediction model, exposure variable(e.g. a settled population) have been used as fundamental explanatory variable under the concept that each trip will be subjected to a probable risk of accident. However, a settled population may be embedded error by exclusion of active population concept. The objective of this research study is to develop macro-level accident prediction model using floating population variable(concept of including a settled population and active population) collected from mobile phone data. The concept of accident prediction models is introduced utilizing exposure variable as explanatory variable in a generalized linear regression with assumption of a negative binomial error structure. The goodness of fit of model using floating population variable is compared with that of the each models using population and the number of household variables. Also, log transformation models are additionally developed to improve the goodness of fit. The results show that the log transformation model using floating population variable is useful for capturing the relationships between accident and exposure variable and generally perform better than the models using other existing exposure variables. The developed model using floating population variable can be used to guide transportation safety policy decision makers to allocate resources more efficiently for the regions(or zones) with higher risk and improve urban transportation safety in transportation planning step.

• Journal of Mechanical Science and Technology
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• 제15권12호
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• pp.1699-1710
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• 2001

The characteristics of methanol and methanol blended (M85) sprays were investigated under atmospheric conditions at various temperature, ranging from on-vaporizing to vaporizing ambient conditions (298∼353 K). From laser scattering images, the macroscopic characteristics of the spray, such as the spray tip penetration and the spray angle, were determined. Entropy concept was introduced to represent homogeneity and PIV analysis was adopted to determine the fluid dynamic information at each location of the spray. The correlation between entropy and vorticity strength enabled us to find their relations. The effect of ambient composition, mainly of viscous effect as affected by CO$_2$levels, was investigated using PIV and entropy analysis. Spray width and entropy value were found to tend to decrease at increased CO$_2$levels.

• 한국자동차공학회논문집
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• 제10권6호
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• pp.44-50
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• 2002

The spray characteristics of GDI(Gasoline Direct Injection) injector affects on engine efficiency and emission of a GDI engine. Thus, many researchers have investigated the spray characteristics and the mixture formation of GDI injector. In this study, it was tried to provide the fundamental data for GDl injector design which effects on the spray macroscopic characteristics such as penetration and spray angle. In addition, the mixture formation analyzed by using entropy analysis. The entropy analysis is based on the concept of statistical entropy, and it identifies the degree of homogeneity in the fuel concentration. The results show that as injection pressure increases but as ambient pressure increases, spray penetration decreases and spray angle doesn't affected by increasing injection pressure and ambient temperature. From the entropy analysis results, we could find that the direct diffusion phenomena is a dominant factor in the formation of a homogeneous mixture at downstream of GDI spray especially in vaporizing conditions.