• Communications of Mathematical Education
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• v.36 no.4
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• pp.469-486
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• 2022

Counting occupies a fundamental and important position in mathematical learning due to its relation to number concepts and numeral operations. In particular, counting up to large numbers is an essential learning element in that it is structural counting that includes the understanding of place values as well as the one-to-one correspondence and cardinal principles required by counting when introducing number concepts in the early stages of number learning. This study aims to derive didactical implications by investigating the possibility of and the strategies for counting large numbers that is expected to have no students' experience because it is not composed of current textbook activities. To do this, 89 second-grade elementary school students who learned the three-digit numbers and experienced group-counting and skip-counting as textbook activities were provided with questions asking how many penguins were in a picture where 260 penguins were irregularly arranged and how to count. As a result of analyzing students' responses in terms of the correct answer rate, the strategy used, and their cognitive characteristics, the incorrect answer rate was very high, and the use of decimal principles, group-counting, counting by one, and partial sum strategies were confirmed. Based on these analysis results, several didactical implications were derived, including the need to include counting up to large numbers as textbook activities.

• Journal of Korea Entertainment Industry Association
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• v.14 no.8
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• pp.153-162
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• 2020

The purpose of this study was to provide fundamental data to cosmetic waxing industry by investigating the using and awareness of cosmetic waxing. The questionnaires were administered to 230 subjects in Gwangju and Jeon-nam regions and the collected were statistically processed using SPSS ver. 21.0 program. The results are as follows: First, the most frequent groups were 20s in age group, married in marital status, professional in occupation, and high school graduation in educational background. For the difference in awareness by their general characteristics, the hair removal techniques most experienced by subjects were shaving and waxing and most of them came to know the waxing through acquaintance. Most of them reported positive awareness for experience of waxing and clean hygiene and neatness accounted for most of reason. The most frequently used place for waxing was professional cosmetic shops (nail, skin, and hair) and the most frequent motivation for waxing was effectiveness for skin hygiene. The areas where waxing is mainly performed were armpit, arm, and leg. The most of subjects received the procedure twice a month and in spring. Most of them reported 'very satisfied' for the procedure. It is expected, based on the results of this study, that the cosmetic waxing industry as a part of the beauty industry that is attracting attentions as a new growth engine for the development of national economy accomplish growth.

• Journal of Software Assessment and Valuation
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• v.17 no.1
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• pp.101-113
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• 2021

In this paper, we introduce a speaker overlap system and look at the process of converting the existed system on the specific framework of artificial intelligence. Speaker overlap is when two or more speakers speak at the same time during a conversation, and can lead to performance degradation in the fields of speech recognition or speaker recognition, and a lot of research is being conducted because it can prevent performance degradation. Recently, as application of artificial intelligence is increasing, there is a demand for switching between artificial intelligence frameworks. However, when switching frameworks, performance degradation is observed due to the unique characteristics of each framework, making it difficult to switch frameworks. In this paper, the process of converting the speaker overlap detection system based on the Keras framework to the pytorch-based system is explained and considers components. As a result of the framework switching, the pytorch-based system showed better performance than the existing Keras-based speaker overlap detection system, so it can be said that it is valuable as a fundamental study on systematic framework conversion.

• Journal of Platform Technology
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• v.10 no.3
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• pp.60-68
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• 2022

As AI-technology develops, interest in the safety of autonomous driving is increasing. Recently, autonomous vehicles have been increasing, but efforts to solve side effects have been sluggish. In particular, night autonomous vehicles have more problems. This is because the probability of accidents is higher in the night driving environment than in the day environment. There are more factors to consider for self-driving at night. Among these factors, reflection of light or reflected light of lighting may be a fundamental cause of night accidents. Therefore, this study proposes method to reduce accidents and improve safety by reducing reflected light generated by the headlights of opposite vehicles or various surrounding light that appear as an important problem in night autonomous vehicles. Therefore, first, in an image obtained by a sensor of a night autonomous vehicle, illumination reflected light is extracted using reflected light characteristic information, and a color of each pixel using a reflection coefficient is found to reduce a special area generated by geometric characteristics. In addition, we find a new area using only the brightness component of the specular area, define it as Illuminated Reflection Light (IRL), and finally present a method to reduce it. Although the illumination reflection light could not be completely reduce, generally satisfactory results could be obtained. Therefore, it is believed that the proposed study can reduce casualties by solving the problems of night autonomous driving and improving safety.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.35 no.5
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• pp.393-402
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• 1990

Studies to obtain a fundamental data to improve the quantity and quality of wheat protein and to select the excellent breeding materials suitable for various uses of it were performed on the focuses of protein content, amino acid composition, and its related quality. The range of seed protein content of crossing block consisted with 319 varieties or lines was from 9.9% to 17.6% with the average of 13.2%. The minimum protein content was showed by Wonkwang, and the maximum by Chungnamjaerae and Suwon 210. Among the Korean native varieties or breeding lines of crossing block, at least twelve lines or varieties were selected as the high-protein wheats. In the effects of environmental conditions, the variations of protein content by cultivating locations and year were showed out to be up to 3.6%, and 3.3%, respectively. But the varietal characteristics of wheat protein were seemed to remain constantly. In the results of amino acid analysis, those related with bread quality, except proline were improved with the increase of seed protein. But the improvement of nutritional quality did not agree with the protein content increase of seed. The total content of amino acid essential to adults was very low with 266.6-273.3mg per one gram of protein compare to the 350mg (free from the amino acid of tryptophan) recommended by FAO/WHO. Especially the limiting amino acid such as methionine, lysine and threonine were critically deficient. The correlation between protein contents and sedimentation values was obtained r=0.656$\^$**/ of average notwithstanding widly different environmental conditions, and in some condition the value was obained about to r=0.956$\^$**/.

• Korean Journal of Ecology and Environment
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• v.55 no.2
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• pp.156-166
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• 2022

Understanding the characteristics of reservoir water quality is fundamental in reservoir ecosystem management. The water quality of reservoirs is affected by various factors including hydro-morphology of reservoirs, land use/cover, and human activities in their catchments. In this study, we classified 83 major reservoirs in South Korea based on nine physicochemical factors (pH, dissolved oxygen, chemical oxygen demand, total suspended solid, total nitrogen, total phosphorus, total organic carbon, electric conductivity, and chlorophyll-a) measured for five years (2015~2019). Study reservoirs were classified into five main clusters through hierarchical cluster analysis. Each cluster reflected differences in the water quality of reservoirs as well as hydromorphological variables such as elevation, catchment area, full water level, and full storage. In particular, water quality condition was low at a low elevation with large reservoirs representing cluster I. In the comparison of eutrophication status in major reservoirs in South Korea using the Korean trophic state index, in some reservoirs including cluster IV composed of lagoons, the eutrophication was improved compared to 2004~2008. However, eutrophication status has been more impaired in most agricultural reservoirs in clusters I, III, and V than past. Therefore, more attention is needed to improve the water quality of these reservoirs.

• Journal of Marine Life Science
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• v.8 no.1
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• pp.68-77
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• 2023

In this study, we investigated the quantitative distribution of microplastics in the surface seawater at 8 points near the Taean Peninsula using fluorescence staining. The study revealed a detection range of microplastics from 0 to 360.5 particles/l, with an average of 149.7 ± 46.0 particles/l. When classifying the microplastics by size, it was found that particles smaller than 50 ㎛ were dominant, although there were differences at Site 3. Moreover, it was not possible to identify clear correlations when comparing the number of microplastics based on collection area and particle size. Various physical and chemical factors, including plastic material, dynamic ocean conditions (such as currents, wind, waves, tides), geological characteristics (topography, slope), sediment materials including coastal organisms, human activities (fishing, development, tourism), and weather conditions (floods, rainfall), affect the behavior of microplastics. Therefore, future efforts should focus on standardizing quantitative analysis methods and conducting fundamental research on microplastic monitoring, including the analysis of environmental factors.

• Journal of Nutrition and Health
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• v.56 no.4
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• pp.404-418
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• 2023

Purpose: This study aimed to analyze the trends in kimchi, vegetable, and fruit consumption among the Korean population and identify the factors associated with this consumption. The goal was to provide fundamental data for developing appropriate guidelines to increase kimchi consumption by understanding its characteristics. Methods: The analysis utilized data from the Korea National Health and Nutrition Examination Survey (KNHANES) conducted between 1998 and 2020. A total of 81,680 adults, aged 30 years or older, were included in the trend analysis. For the analysis of factors associated with kimchi, vegetable, and fruit intake, a subgroup of 22,122 adults aged 30 years or older from the KNHANES (2016-2020) was divided into two groups: 30-64 years old and 65 years old or older. Since the KNHANES data employed a complex sampling design, the statistical analysis was conducted using the appropriate complex sampling design method. Results: The overall consumption of kimchi exhibited a declining trend among both men and women. Specifically, there was a significant decline in the intake of baechu kimchi among both genders. The decline in kimchi consumption above the standard was associated with a decrease in meal frequency and an increase in the frequency of eating alone. However, the patterns for unsalted vegetables and fruits differed compared to kimchi. Conclusion: In this study, there was a decline in kimchi consumption among both men and women, and the potential factors associated with this trend included Westernized dietary habits, the presence of a spouse who influenced dietary habits, and an increased frequency of solitary dining due to the rise in single-person households. Therefore, it is necessary to develop dietary guidelines that consider these factors.

• Geophysics and Geophysical Exploration
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• v.26 no.3
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• pp.114-125
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• 2023

The physics-informed neural network (PINN) has been proposed to overcome the limitations of various numerical methods used to solve partial differential equations (PDEs) and the drawbacks of purely data-driven machine learning. The PINN directly applies PDEs to the construction of the loss function, introducing physical constraints to machine learning training. This technique can also be applied to wave equation modeling. However, to solve the wave equation using the PINN, second-order differentiations with respect to input data must be performed during neural network training, and the resulting wavefields contain complex dynamical phenomena, requiring careful strategies. This tutorial elucidates the fundamental concepts of the PINN and discusses considerations for wave equation modeling using the PINN approach. These considerations include spatial coordinate normalization, the selection of activation functions, and strategies for incorporating physics loss. Our experimental results demonstrated that normalizing the spatial coordinates of the training data leads to a more accurate reflection of initial conditions in neural network training for wave equation modeling. Furthermore, the characteristics of various functions were compared to select an appropriate activation function for wavefield prediction using neural networks. These comparisons focused on their differentiation with respect to input data and their convergence properties. Finally, the results of two scenarios for incorporating physics loss into the loss function during neural network training were compared. Through numerical experiments, a curriculum-based learning strategy, applying physics loss after the initial training steps, was more effective than utilizing physics loss from the early training steps. In addition, the effectiveness of the PINN technique was confirmed by comparing these results with those of training without any use of physics loss.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.19 no.2
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• pp.111-116
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• 1983

In order to furnish the fundamental data for the domestic production of magnetic compass and the prescription of standardization about it in Korea, authors made the helmholtz coil and investigated the characteristics of them. Subsequently, the damping curves of T190 and T165 compasses in the helmholtz coil were measured and analyzed the performance of those compass. The results obtained are as follows; 1. The relation between electric current (I sub I) to flow in the helmholtz coils, that the thickness of coil is 1mm, diameter 1m, winding number 117, and intensity of magnetic field is presented as follows. Vertical magnetic force: Z(Gauss)=0.34+1.506 I sub(i) Horizontal magnetic force: H(Gauss)=0.183+1.506 I sub(i) 2. Period of T190 compass is longer than T165 compass in all horizontal magnetic force. In the amplitude, the former is larger than the latter above 0.08 Gauss, but this phenomenon is opposed to that below 0.08 Gauss. 3. As the porizontal magnetic force is intensive, period of magnetic compass is short, amplitude is large, and damping degree and damping factor are small. The time elapsed to the principal points of damping curve is proportional to the -0.65 power of the horizontal magnetic force.