• Journal of Radiation Protection and Research
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• 제33권1호
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• pp.21-26
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• 2008

Activity가 20만 dpm인 고상 $^3H$ 표준선원을 사용하여 액체섬광계수기에 대한 교정을 수행할 경우 환경시료와는 Activity 및 Geometry 차이가 존재하고, 계측조건 차이로 인해 많은 불확실성이 존재할 수 있지만 이에 대한 연구결과가 없는 실정이다. 따라서 본 연구에서는 민감도분석을 통해 최적의 계측조건을 도출한 후 그 결과에 근거하여 Geometry 및 Activity 차이에 의한 영향을 정량적으로 평가하였고, 각 항목에 의한 영향이 나타날 경우 추가실험을 통해 원인을 규명하였다. 계측 결과에 대한 검증을 수행하기 위해 Chi-square test와 방사능오차분석을 수행하였고, 민감도분석 결과 본 연구에서 제안한 방법이 기존 방법에 비해 $1{\sim}3%$정도 오차가 감소하였다. 방사능오차분석 결과 Activity 차이에 의한 영향은 무시할 수 있었지만 Geometry 차이에 의한 영향이 크게 나타났고, 이에 대한 원인을 규명한 결과 비수용성인 플라스틱용기는 반사체 역할을 하였고, Activity가 높을수록 플라스틱에 의한 영향은 무시할 수 있었으며, 선원형태 차이에 의한 영향이 지배적인 것으로 나타났다.

• Human Ecology Research
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• 제55권2호
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• pp.125-140
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• 2017

This study composed spatial cognition tasks within the system of geometric area to study children's spatial cognition development systematically. It surveyed children's execution of direction, rotation, symmetry, conjugation, and part/whole cognition tasks. A spatial geometry cognition task set (consisting of total 27 sub-tasks) was presented to 60 children (20 each in groups of 3-, 4-, and 5-year-old) in order to confirm how children's execution of spatial geometry cognition changed depending on children's age and sex as well as if the execution of the spatial geometry cognition showed a difference after each task area. As a result, the execution of the whole direction task and the part/whole task gradually increased between age 3 and age 5. The execution of the whole rotation task, whole symmetry task, and whole conjugation task rapidly increased between age 3 and age 4. Significant sexual difference did not appear in the execution of spatial geometry cognition tasks. The execution of the conjugation and part/whole task was high in each task area, and the execution of the direction, rotation, and symmetry task was relatively low. In addition, the difference of task execution appeared in the sub-tasks of direction, symmetry, and conjugation areas. This result suggests the theoretical discussion possibility of children's spatial geometry cognition development. In addition, the empirical results of this study can be applied to child education plans and activity compositions appropriate for child development.

• 한국수학사학회지
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• 제18권4호
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• pp.29-38
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• 2005

이 논문에서는 고대 그리스 시대부터 비롯되었던 논리 전개 방식 토는 발견술에서 출발하여 19세기 사영기하학의 방법론에 이르기까지 종합법과 해석법의 대립을 다룬다. 애초에 발견술로서 차이를 드러냈던 두 방법은 출발 자체가 주로 기하학영역에서 비롯되었듯이 18세기에 이르러 기하학의 양대 분야, 즉 해석기하학과 종합기하학으로까지 나뉘게 되는 토대를 제공한다. 19세기에 이르러서는 사영기하학 내부에서 수학의 본성에 대하여 다른 관점을 가지는 데서 야기된 대립 양상까지 보이게 된다 그렇지만 결국 양자의 변증법적 지양을 도모했던 고대에서와 마찬가지로 더 이상 대립의 근거가 없어지기에 이르는 과정을 밝힌다.

• Journal of Korean Society for Atmospheric Environment
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• 제23권E1호
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• pp.29-38
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• 2007

A cylindrical tube connection that has a voltage difference and is separated electrically by an insulator was modelled. The penetration efficiencies of charged particles passing through the connector tube were investigated. Typically, as the particle size decreases and the applied voltage difference increases, the penetration efficiency decreases. To assess the effect of the electrode geometry, various lengths of electric insulator and aerosol flow rate with a fixed tube length and tube diameter were used when calculating penetration efficiencies. The comparison of penetration efficiencies for various electrode geometry setups suggests that the penetration efficiency can be described as a function of the product of applied voltage and electrical mobility of charged particles. The diffusion loss from this and previous studies are compared. Further, an explicit form for penetration efficiency is provided as a function of a new non-dimensional parameter, $Es(=Z_pV/U_{avg}W);\;P_{es}=0.2{\cdot}{\exp}(-Es/0.6342)+0.8{\cdot}{\exp}(-Es/4.7914)$.

• 한국수학교육학회지시리즈A:수학교육
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• 제47권2호
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• pp.113-133
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• 2008

This study is to develop the methods of specifying teaching that can consider individual differences in middle school geometry education. The purpose of this study is to decide the variations causing individual differences and to find the proper learning methods considering the variations. Through literature review, this study made it clear that the matter of individual difference is just the matter of talent and examined what factors make up mathematical talents. On the basis of the result, five important variations and fourteen subordinate factors were determined. I researched into the learning methods that consider the determined subordinate factors using the 'congruence' unit of middle school textbooks and developed specific learning methods for each of the subordinate factors through specific congruence problem solving situations. This study can be summarized as follows : I researched the studies of mathematical ability conducted by several educators and psychologists. This research is divided into the early study and the developed study of mathematical ability. Through this study five specific variations were determined. And fourteen subordinate factors have been made from the determined variations. The specific learning methods based on individual differences was developed according to the fourteen subordinate factors on the basis of middle school textbooks of Korea, Gusev's textbook, problem books of Russia, and etc.

• Nuclear Engineering and Technology
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• 제23권1호
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• pp.41-48
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• 1991

처분장에서의 방사성 핵종 이동 연구에서 많은 학자들이 일차원 모델이나 평면좌표 모델을 가정하여 사용하고 있다. 이러한 시도들은 정당한 가정이라는 것을 보여야 할 것이다. 본 논문에서는 충전물질에서의 핵종이동에서 사용한 가정, 즉 원주좌표계를 평면좌표계로 단순화하였던 가정을 검증하고자 한다. 본 연구 결과, 충전물질층의 외경과 폐기물 고화체의 직경의 비가 1에 가까울수록 평면좌표계의 가정은 원주좌표계의 결과와 잘 일치함을 알 수 있으며 그 비가 커져도 두 좌표계의 오차는 상대적으로 적음을 알 수 있다. 또한 평면좌표계의 가정이 보수적인 결과를 준다.

• 대한수학회지
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• 제59권6호
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• pp.1103-1137
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• 2022

Our motivation in this note is to find equal hyperharmonic numbers of different orders. In particular, we deal with the integerness property of the difference of hyperharmonic numbers. Inspired by finiteness results from arithmetic geometry, we see that, under some extra assumption, there are only finitely many pairs of orders for two hyperharmonic numbers of fixed indices to have a certain rational difference. Moreover, using analytic techniques, we get that almost all differences are not integers. On the contrary, we also obtain that there are infinitely many order values where the corresponding differences are integers.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2005년도 Proceedings of ISRS 2005
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• pp.182-185
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• 2005

Satellite cameras are calibrated before launch in detail and in general, but it cannot be guaranteed that the geometry is not changing during launch and caused by thermal influence of the sun in the orbit. Modem satellite imaging systems are based on CCD-line sensors. Because of the required high sampling rate the length of used CCD-lines is limited. For reaching a sufficient swath width, some CCD-lines are combined to a longer virtual CCD-line. The images generated by the individual CCD-lines do overlap slightly and so they can be shifted in x- and y-direction in relation to a chosen reference image just based on tie points. For the alignment and difference in scale, control points are required. The resulting virtual image has only negligible errors in areas with very large difference in height caused by the difference in the location of the projection centers. Color images can be related to the joint panchromatic scenes just based on tie points. Pan-sharpened images may show only small color shifts in very mountainous areas and for moving objects. The direct sensor orientation has to be calibrated based on control points. Discrepancies in horizontal shift can only be separated from attitude discrepancies with a good three-dimensional control point distribution. For such a calibration a program based on geometric reconstruction of the sensor orientation is required. The approximations by 3D-affine transformation or direct linear transformation (DL n cannot be used. These methods do have also disadvantages for standard sensor orientation. The image orientation by geometric reconstruction can be improved by self calibration with additional parameters for the analysis and compensation of remaining systematic effects for example caused by a not linear CCD-line. The determined sensor geometry can be used for the generation? of rational polynomial coefficients, describing the sensor geometry by relations of polynomials of the ground coordinates X, Y and Z.

• 한국화재소방학회논문지
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• 제25권4호
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• pp.74-81
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• 2011

고층건물의 수직통로 형상이 연돌효과의 차압과 중성대 위치에 미치는 영향을 알아보고, 연돌효과의 발생현상을 가시화하기 위하여 3가지 형상의 수직통로, 즉 단순 수직통로, 승강기 수직통로 및 계단실 수직통로에 대하여 CFD 모델인 FDS(ver. 5.3) 프로그램을 사용하여 수치해석 하였다. 연돌효과 초기(t = 10 s) 차압은 승강기 수직통로인 경우(79.3 Pa)가 이론식 계산 결과(78 Pa)와 잘 일치하였다. t = 300 s 시점에서 중성대 위치는 3가지 경우 모두 49 m 이상으로 이론식 결과 보다 5 m 이상 높게 나타났다. 수직통로 상부와 하부지점 사이의 최대차압은 수직통로의 구조가 복잡할수록 감소하였다. 연돌효과 가시화를 통하여 수직통로 형상에 따라 연돌효과에 차이가 있다는 것을 알 수 있었다.

• Kyungpook Mathematical Journal
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• 제50권1호
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• pp.81-87
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• 2010

We modify the definition of difference algebra given by J. Meng to obtain a structure which is a directoid with sectional switching involutions with respect to the given partial order. Moreover, we show that this is a representation of our skew difference algebras because every such directoid can be converted into a skew difference algebra.