• School Mathematics
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• v.13 no.4
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• pp.599-614
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• 2011

According to prior research studies, comparison of two data sets promote informal and formal statistical reasoning, which may mediate descriptive and inferential statistics. However, there has been relatively little attention given to the mediation of both descriptive and inferential statistics. We attempted to identify which statistical concepts or factors students used and how they applied concepts or factors to make decisions when they compared data sets. We also investigated the characteristics and changes of the view of concepts and factors. As a result, we identified that students paid attention to data value, center, spread, and sample, which are important factors of inferential statistics. Students' understanding of each factors were sometimes appropriate for inferential statistics, but sometimes not. From the results, we suggest instructional ideas for a task which can connect descriptive and inferential statistics.

• The Korean Journal of Applied Statistics
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• v.32 no.5
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• pp.703-720
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• 2019

The influence of temperature on electricity demand is increasing due to extreme weather and climate change, and the climate impacts involves nonlinearity, asymmetry and complexity. Considering changes in government energy policy and the development of the fourth industrial revolution, it is important to assess the climate effect more accurately for stable management of electricity supply and demand. This study aims to analyze the effect of temperature change on electricity demand using the partial linear model. The main results obtained using the time-unit high frequency data for meteorological variables and electricity consumption are as follows. Estimation results show that the relationship between temperature change and electricity demand involves complexity, nonlinearity and asymmetry, which reflects the nonlinear effect of extreme weather. The prediction accuracy of in-sample and out-of-sample electricity forecasting using the partial linear model evidences better predictive accuracy than the conventional model based on the heating and cooling degree days. Diebold-Mariano test confirms significance of the predictive accuracy of the partial linear model.

• Journal of Korean Society of Forest Science
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• v.103 no.1
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• pp.12-22
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• 2014

This study was carried out to classify forest communities and to aggregate forest cover types for the complex and diversified natural forest areas of Hwangaksan, Bakseoksan, Deogyusan, and Jirisan in southern region of Baekdudaegan Mountains. The vegetation data were collected by point-centered quarter sampling method. Eight hundred fifty one sample points were subjected to cluster analysis to classify 18 forest communities, which were aggregated into 7 representative forest cover types on the basis of community similarity from composition of canopy species. They were mixed mesophytic forest cover type, the others deciduous forest cover type, Quercus variabilis-Quercus serrata cover type, Quercus mongolica cover type, Pinus densiflora cover type, Carpinus laxiflora cover type, and Abies koreana cover type. The Quercus mongolica cover type was most widely distributed in the study areas, and this cover type tended to occur in the place of higher altitude as latitude was getting lower. Mixed mesophytic forest and the others deciduous forest cover type were commonly distributed in the areas of valley, on the other hand, Quercus mongolica cover type and Pinus densiflora cover type tended to be distributed in the areas of ridge.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.3
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• pp.333-340
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• 2022

The COVID-19 has made everyone anxious and people need to keep their distance. It is necessary to conduct collective assessment and screening of college students' mental health in the opening season of every year. This study uses and trains a multi-layer perceptron neural network model for deep learning to identify facial emotions. After the training, real pictures and videos were input for face detection. After detecting the positions of faces in the samples, emotions were classified, and the predicted emotional results of the samples were sent back and displayed on the pictures. The results show that the accuracy is 93.2% in the test set and 95.57% in practice. The recognition rate of Anger is 95%, Disgust is 97%, Happiness is 96%, Fear is 96%, Sadness is 97%, Surprise is 95%, Neutral is 93%, such efficient emotion recognition can provide objective data support for capturing negative. Deep learning emotion recognition system can cooperate with traditional psychological activities to provide more dimensions of psychological indicators for health.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.7
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• pp.363-371
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• 2019

The purpose of this research is to provide data for the relations between lifestyle, stress and hypertension in a group of construction Temporary employee. The methods taken in this study was to survey the general characteristics and stress in the group, and figure out the relations between lifestyle and hypertension. This study targeted at 301 Temporary employee. in Young-dong for six months (2014~2015). Data analysis used errors and percentages, chi-square tests, one-way ANOVA analysis, independent sample t-test, chi-square test and multivariate logistic regression. The study shows that no relations between age and hypertension, but according to job characteristics, aggravate lifestyle just like smoking(P=0.049), eating habit(P=0.012), physical(p=0.022) & psychological(p=0.011) state there is an effect on hypertension. Based on the results of this study, it is found that temporary workers in small and medium-sized construction companies with high work-related disaster rates need to improve their living habits and physical psychological conditions and manage high blood pressure, as well as research and management of chronic diseases such as obesity, diabetes and dyslipidemia.

• The Korean Journal of Pharmacology
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• v.10 no.1 s.15
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• pp.31-40
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• 1974

1. The authors investigated the effects of $PGE_1$ on the action of sympathomimetics in the vas deferens of guinea-pig, comparing with those in the rat vas deferens, and also the action of $PGE_1$ on the motility of nerve-free smooth muscle of chick amnion. 2. In the isolated guinea-pig vas deferens, the actions of phenylephrine and norepinephrine were much potentiated by pretreatment with $PGE_1$. Futher, in the isolated hypogastric nerve-vas deferens preparation of guinea-pig, effects of phenylephrine, norepinephrine and tyramine on the contractile response of vas to the hypogastric nerve stimulation and to the transmural stimulation were also augumented especially in tension by $PGE_1$-pretreatment. 3. In the isolated hypogastric nerve-vas preparation of rat, both contractile responses to hypogastric nerve and transmural stimulation were slowly reduced by treatment with $PGE_1$ and the potentiated effect of phenylephrine or norepinephrine was not observed in spite of pretreatment with $PGE_1$. 4. The actions of phenylephrine and norepinephrine on the denervated vas deferens of guinea-pig were also enhanced by $PGE_1$ as it were in the intact vas deferens, but there was no significant effect by $PGE_1$ on the action of norepinephrine in the denervated rat vas deferens. 5. $PGE_1$ in low concentration $(10^{-8}g/ml)$ did not affect the spontaneous motility of nerve-free smooth muscle of chick amnion ($9{\sim}11$ th day incubated chick), but in large concentration $(5{\times}10^{-8}g/ml)$ it caused irregular and slightly inhibitory movement. Pretreatment with $PGE_1$ on chick amnion did not exert any change on the action of phenylephrine applied. However, the stimulatory action of physostigmine on the chick amnion was a little antagonized by the low concentration of $PGE_1$. 6. It might be summarized that there is species difference between the actions of $PGE_1$ on the vas deferens of guinea-pig and that of rat, and the action of $PGE_1$ on the guinea-pig vas deferens might be mediated by the other mechanism rather than by direct action on the vas musculature.

• Journal of Korean Society of Forest Science
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• v.80 no.4
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• pp.360-368
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• 1991

Utilizing chi-square test statistics, inter-species association and covariation were analyzed for the 37 woody plant species in a deciduous forest dominated by Quercus mongolica and Q. variabilis. within 50 temporarily established $20m{\times}20m$ square quadrats, the association for each pair of species was presented based on the presence-absence parameters. Acer palmatum had significant positive association with Acer mono and Kalopanax pictus, but negative association with Pinus densiflora. Other positively associated species pairs were Prunus sargentii-Macckia amurensis, Quercus serrata-Kalopanax pictus, Symplocos chinensis var. pilosa-Euonymus oxyphyllus, and Ulmus davidiana var. japonica-Lindera obtusiloba. The covariation far each pair of species was evaluated based on the quantitative measures, density and basal area. Overall results showed that the association and covariation values among species generally agreed with each other. Because covariation was calculated by density and basal area of the tallied species in the sample plots, the number of species pairs of covariation tended to be greater than those of association. Especially, Pinus densiflora, considered to be pioneer species in the successional stage, had negative covariation with most of climax species. These ecological information could be applied to silvicultural practices, such as ecosystem classification, establishment of mixed hardwood forest, and tending operations for marking crop trees and desirable species.

• Korean Journal of Plant Taxonomy
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• v.45 no.4
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• pp.306-317
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• 2015

This study was conducted to address the taxonomic status of the Korean endemic species Saxifraga octopetala, which is sometimes considered conspecific to Micranthes manchuriensis. Extensive molecular phylogenetic analysis using nrITS sequences as well as morphological examination of type specimens of the two species were undertaken to ascertain the phylogenetic position and species delimitation of S. octopetala. In the resulting nrITS trees, a total of 65 accessions representing S. octopetala grouped together and nested within the Micranthes clade, exhibiting a close relationship with M. nelsoniana and M. manchuriensis. Multiple accessions of M. manchuriensis collected from China and Russia also formed a clade, showing a sister group relationship with M. nelsoniana var. pacifica and M. fusca. The ambiguous species entity of S. octopetala is thought to have originated from Nakai's misinterpretation of Wilford's collection (type specimens of M. manchuriensis), which is a complex collection including an inflorescence of M. nelsoniana. In spite of apparent morphological similarity between S. octopetala and M. manchuriensis, they differ in the presence and absence of underground stolons. The distinct position of S. octopetala within the Micranthes clade on the nrITS tree suggests that it should retain species status in Micranthes. Thus a new combination (Micranthes octopetala) is proposed.

• Journal of Digital Convergence
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• v.18 no.9
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• pp.277-283
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• 2020

The purpose of this study was to identify the risk factors influencing stroke. The research method was used two-stage stratified cluster sampling using data from the National Health and Nutrition Survey (2016-2018). This study subjects performed a complex sample logistic regression analysis on adults aged 19 or older. Risk factors affecting stroke were shown as follows: in age groups, odds ratio were conformed when people are in their 70s, the rate is 8.861 times higher; when they are in their subjective health conditions, the odds ratio are 4.501 times higher in the bad groups; odds ratio was 3.158 times higher in the group diagnosed with hypertension and 1.598 times higher in the group diagnosed with diabetes. The result of this study found that chronic diseases such as high blood pressure and diabetes and the management of senior citizens are important because stroke is dangerous and can be managed through prevention.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.49 no.1
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• pp.19-30
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• 2012

For digital data compression, the quantization is the main part of the lossy source coding. In order to improve the performance of quantization, the vector quantizer(VQ) can be employed. The encoding complexity, however, exponentially increases as the vector dimension or bit rate gets large. Much research has been conducted to alleviate such problems of VQ. Especially for high bit rates, a constrained VQ, which is called the sample-adaptive product quantizer(SAPQ), has been proposed for reducing the hugh encoding complexity of regular VQs. SAPQ has very similar structure as to the product VQ(PQ). However, the quantizer performance can be better than the PQ case. Further, the encoding complexity and the memory requirement for the codebooks are lower than the regular full-search VQ case. Among SAPQs, 1-SAPQ has a simple quantizer structure, where each product codebook is symmetric with respect to the diagonal line in the underlying vector space. It is known that 1-SAPQ shows a good performance for i.i.d. sources. In this paper, a study on designing 1-SAPQ for the first-order Markov process. For an efficient design of 1-SAPQ, an algorithm for the initial codebook is proposed, and through the numerical analysis it is shown that 1-SAPQ shows better quantizer distortion than the VQ case, of which encoding complexity is similar to that of 1-SAPQ, and shows distortions, which are close to that of the DPCM(differential pulse coded modulation) scheme with the Lloyd-Max quantizer.