• Journal of the Korean Data and Information Science Society
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• v.22 no.6
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• pp.1217-1222
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• 2011

In this paper, we show that any circular density can be closely approximated by an exponential family of distributions. Therefore we propose an exponential family of distributions as a new family of circular distributions, which is absolutely suitable to model any shape of circular distributions. In this family of circular distributions, the trigonometric moments are found to be the uniformly minimum variance unbiased estimators (UMVUEs) of the parameters of distribution. Simulation result and goodness of fit test using an asymmetric real data set show usefulness of the novel circular distribution.

• Communications of the Korean Mathematical Society
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• v.13 no.4
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• pp.903-911
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• 1998

We show that if r $\leq$ 2, the average error of the Trapezoidal rule is proportional to $n^{-min{r＋l, 3}}$ where n is the number of mesh points on the interval [D, 1]. As a result, we show that the Trapezoidal rule with equally spaced points is optimal in the average case setting when r $\leq$ 2.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.1
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• pp.84.1-84.1
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• 2019

722 open clusters in the Sim open cluster catalogue show the outermost structure of open clusters. The catalogue is based on the proper motion and parallax of the stars. These results reveal the hidden structures of weak membership signals in the field star contamination. It contains the tidal tails, flattened structure along the galactic plane, interacting double clusters and very poor and spread clusters. We will show these interesting structures.

• Bulletin of the Korean Chemical Society
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• v.27 no.7
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• pp.1048-1052
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• 2006

Ab initio calculations of the structure, atomic charges and natural bond orbital (NBO) have been performed at HF/6-311G** and B3LYP/6-311G** levels for the title compound of dibenzothiazyl-disulfide. The calculated results show that the two nitrogen atoms have the biggest negative charges and they are the potential sites to react with the metallic ions, which make the title compound become a di-dentate ligand. Vibrational frequencies of the title compound have been obtained and compared with the experimental value and the comparison indicates that B3LYP/6-311G** level is better than HF/6-311G** level to predict the vibrational frequencies for the system studied here. For the title compound, electronic absorption spectra calculated by time?ependent density functional theory (TD-DFT) are more accurate than Hartree-Focksingle-excitation CI (CI-Singles) method. NBO analyses show that the electronic transitions are mainly derived from the contribution of bands $\pi\rightarrow\pi^{*}$. Thermodynamic calculated results show that the formation of the title compound from 2-mercaptobenzothiazole is a spontaneous process at room temperature with the change of free Gibbs being negative value.

• Journal of Astronomy and Space Sciences
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• v.25 no.1
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• pp.19-24
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• 2008

We present the full BVR light curves and five times of minima of WZ Cep to provides a complete photometric solution and to confirm the long term variation of the light curves. Our light curves show symmetry while previous light curves of Hoffmann (1984) show a high degree of asymmetry (the O'Connell effect). The BVR light curves were analyzed by the method of Wilson-Devinney Differential Correction. Our photometric results show a good agreement with those of Djurasevic et al. (1998).

• Journal of the Korean Society of Earth Science Education
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• v.3 no.1
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• pp.18-27
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• 2010

The purpose of this study is to investigate effects of instruction with stories on elementary school students' science learning and memory. For the purpose, this researcher sampled 3 classes in their 3th grade from an elementary school. Out of the three classes, two were designated as the comparative group consisting of 70 students and the other, the experimental group, 32 students. The former group was applied instruction treatment under the 7th national curriculum of education. The other group was instructed with a story book that contained stories students already knew which were somewhat rearranged to comply with contents of a relevant curricular course. Results of the study can be described as follows. First, academic achievement test was made immediately after the treatment to show that the experimental group was significantly higher in scores for memory and understanding in the section of 'Finding Constellations' that the other group. Second, the two groups' academic achievements in relation to the section, 'Finding Constellations' were tested 3 months after the treatment to show that the experimental group was significantly higher in scores for memory and understanding than the comparative group. Such achievements within the groups were tested 3 months after the treatment to find that both of the two groups didn't show statistically significant differences.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.1
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• pp.34.3-34.3
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• 2019

We report our discovery of observational evidence for the coherence between galaxy rotation and the average motion of neighbors. Using the Calar Alto Legacy Integral Field Area (CALIFA) survey data analyzed with the Python CALIFA STARLIGHT Synthesis Organizer (PyCASSO) platform, and the NASA-Sloan Atlas (NSA) catalog, we estimate the angular momentum vectors of 445 CALIFA galaxies and build composite maps of their neighbor galaxies on the parameter space of velocity versus distance. The composite radial profiles of the luminosity-weighted mean velocity of neighbors show striking evidence for dynamical coherence between the rotational direction of the CALIFA galaxies and the average moving direction of their neighbor galaxies. The signal of such dynamical coherence is significant for the neighbors within 800 kpc distance from the CALIFA galaxies with a confidence level of $3.5{\sigma}$, when the angular momentum is measured at the outskirt ($Re<R{\leq}2Re$) of each CALIFA galaxy. We also find that faint or kinematically misaligned galaxies show stronger coherence with neighbor motions than bright or kinematically well-aligned galaxies do. Our results show that the rotation of a galaxy, particularly at its outskirt, may be significantly influenced by recent interactions with its neighbors.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.109-109
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• 2022

The global population is increasing every year, and the amount of food waste is also increasing. Direct landfilling of food waste has been prohibited since 2005, and in accordance with the London Convention in 2013, the discharge of livestock manure, sewage sludge, and food waste into the sea is prohibited. In the case of incineration to treat the discharged food waste, the heat point is lowered due to the moisture in the food waste itself, so fuel must be added. Therefore, this study was conducted to get basic data for setting the limit of application by investigating the growth and yield of crops after treating food waste dry powder mixed fertilizer (MF) on red pepper. In the experiment, continuous cultivation was carried out for two years in 2021 (1st year) and 2022 (2nd year). The treatment groups were set as Not Treatment (NT), Chemical Fertilizer (CF), Mixed Fertilizer (MF), Mixed Fertilizer×2 (MF×2). After harvest, crop growth and yield were investigated. As a result of the 1st years of growth survey, CF, MF, MF×2 show significant difference in shoot length compared to NT. About fresh weight and dry weight, CF show significant difference compared to NT. The 2nd years of growth survey, the shoot and root length, fresh weight did not show significant difference with NT. In case of dry weight, MF is significant increased compared to NT. As a result of the yield survey of the 1st year, all treatment groups did not show a significance in yield compared to the NT. In case of 2nd year, all treatment groups show significantly increased value compared to NT. The yield of MF was highest among the treatment groups. In the future, it is thought that it is necessary to quantitatively evaluate the effect of food waste dry powder mixed fertilizer through additional experiments and continuous cultivation, and to establish an appropriate amount of use and establishment of a manual based on this.

• Journal of the Korean Institute of Intelligent Systems
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• v.15 no.3
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• pp.389-394
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• 2005

The purpose of this paper is to introduce the notions of L-fuzzy topological towers by using a completely distributive lattic L and show that the category L-FPrTR of L-fuzzy pretopoplogical tower spaces and the category L-FPsTR of L-fuzzy pseudotopological tower spaces are extensional topological constructs. And we show that L-FPsTR is the cartesian closed topological extension of L-FPrTR. Hence we show that L-FPsTR is a topological universe.

• Journal of the Korean earth science society
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• v.40 no.4
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• pp.436-445
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• 2019

This study presents how two types of integrated science and engineering lessons affect students' engineering problem solving skills and their perceptions of engineering. In total, 146 middle school students participated in this study. Eighty-six students participated in the Type I lesson (complete engineering design lesson with a science knowledge application) and 60 students participated in the Type II lesson (engineering design without a science knowledge application). Two main datasets, (1) students' Creative Engineering Problem Solving Propensity (CEPSP) measurement scores and (2) open-ended survey questions about students' perceptions of engineering, were collected before and after the lessons. The results of this study show that after participating in the Type I lesson, students' CEPSP scores significantly increased, whereas the CEPSP scores of the students who participated in the Type II lesson did not increase significantly. In addition, students who participated in the Type I lesson perceived engineering and the engineering integrated science lesson differently compared to the students who participated in the Type II lesson. The results of this study show that engineering integrated science, technology, engineering & mathematics (STEM) lessons should include a complete engineering design and a science knowledge application to improve students' engineering problem solving skills.