• Korean Journal of Remote Sensing
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• v.24 no.2
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• pp.213-222
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• 2008

Although hyperspectral sensing data have shown great potential to derive various surface information that is not usually available from conventional multispectral image, the acquisition of proper hyperspectral image data are often limited. To use ground-based hyperspectral camera image for remote sensing studies, radiometric calibration should be prerequisite. The objective of this study is to develop radiometric calibration procedure to convert image digital number (DN) value to surface reflectance for the 120 bands ground-based hyperspectral camera. Hyperspectral image and spectral measurements were simultaneously obtained from the experimental target that includes 22 different surface materials of diverse spectral characteristics at wavelength range between 400 to 900 nm. Calibration coefficients to convert image DN value to at-sensor radiance were initially derived from the regression equations between the sample image and spectral measurements using ASD spectroradiometer. Assuming that there is no atmospheric effects when the image acquisition and spectral measurements were made at very close distance in ground, we were also able to derive calibration coefficients that directly transform DN value to surface reflectance. However, these coefficients for deriving reflectance values should not be applied when the camera is used for aerial image that contains significant effect from atmosphere and further atmospheric correction procedure is required in such case.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.5
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• pp.477-484
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• 2015

Environmental effect of water-saving irrigation on the emissions of greenhouse gases (GHGs) has not been well investigated. The objective of this study was to measure the effect of water-saving irrigation on GHGs as well as water use and rice production yield in paddy field condition in Korea. Four experimental runoff plots of 4x35 m in size were prepared at an existing paddy field. GHGs emission was measured during the 2012~2013 growing seasons while a Japonica rice variety was cultivated. Four different water management methods, 1) Continuous Flooding (CF), 2) Intermittent Drainage (ID), 3) Water Saving (WS), and 4) CF+WS, were used during a rice growing season to compare the effects of water management methods on GHGs emission. CF method is flooding all the time, ID method makes paddy water drained 40 days after transplanting for about two weeks, WS method maintains 2~3 cm water-level, which should be refilled when the water-level decreased to about 0 cm, and CF+WS method combines CF method before 30 days after transplanting (DAT) and WS method after 30 DAT. Regardless of water management methods, paddy field water was drained about 30 days before harvest. Amount of GHGs emission from WS plot was reduced by 69.3% compared to that from CF plot and by 59.0% compared to that from ID plot. Amount of GHGs emission from CF+WS plot was reduced by 60.7% compared to that from CF plot and by 47.5% compared to that from ID plot. Weed occurrence in CF+WS plots was reduced to 62.2% in comparison with the WS plot, implying that CF+WS plot showed the best effect to mitigation of the greenhouse gas emission in the atmosphere.

• The Journal of the Korea Contents Association
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• v.21 no.6
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• pp.505-512
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• 2021

This study is to strengthen the competitiveness of 5-star hotel restaurants in Seoul, and the paired sample t-test was used. As a result of the study, first, the importance variables of hotel restaurants were measured as high variables such as'taste and quality of food(4.30)' and'diversity of menus(4.17)'. Second, the variables satisfied by customers visiting hotel restaurants were 'quantity of food(3.86)', 'taste and quality of food(3.78)', and 'diversity of menus(3.75)', etc. were surveyed. Third, as a result of IPA analysis, the variables in the first quadrant were the restaurant staff's expertise, cleanliness of the restaurant, the taste and quality of the food, the variety of menus, rapid service, food plating, the amount of food served, and the atmosphere of the restaurant. External environment, etc. were derived. In the second quadrant, cleanliness of restaurant tableware, freshness of food, and restaurant view were investigated. In the third quadrant, the reputation, restaurant toilet cleanliness, table cleanliness, parking facilities, transportation and convenience, etc. belong to this. Finally, variables belonging to the fourth quadrant were investigated such as reasonable price, cost-effectiveness and affordability, friendliness of restaurant staff, clothing and appearance of restaurant staff, and restaurant interior.

• Korean Journal of Mineralogy and Petrology
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• v.33 no.4
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• pp.439-450
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• 2020

Global warming caused by the emission of greenhouse gases into the atmosphere is being treated as a major problem for the human life, and mineral carbonation is drawing attention as one of many countermeasures against this situation. In this study, mineral carbonation experiments using autoclaved lightweight concrete (ALC) were performed under various conditions to determine its potential as a carbonation material. ALC can be regarded as a promising material for carbonation because it contains about 27 wt.% of CaO, a major component of mineral carbonation. The CaCO3 content produced as a result of the carbonation of ALC calculated on the assumption that all of the CaO content participates in mineral carbonation is about 40 wt.%. The optimum conditions for the mineral carbonation reaction from ALC are the solid-liquid ratio of 0.01 and the reaction time of 180 minutes when calcite is considered as a single product, or 0.06 and 180 minutes when mixture of calcite and vaterite can be considered. The coexistence of vaterite with calcite at solid-liquid ratio of 0.06 or higher was interpreted to be the case where vaterite formed in the later stage and did not change to calcite until the reaction was completed.

• Atmosphere
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• v.32 no.2
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• pp.103-118
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• 2022

This study evaluates the simulated meteorological fields with a particular focus on the low-level wind, which plays an important role in air pollutants dispersion, under the varying synoptic environment. Additionally, the effects of subgrid-scale orography parameterization and improved topography/land-use data on the simulated low-level wind is investigated. The WRF model version 4.1.3 is utilized to simulate two cases that were affected by different synoptic environments. One case from 2 to 6 April 2012 presents the substantial low-level wind speed over the Korean peninsula where the synoptic environment is characterized by the baroclinic instability. The other case from 14 to 18 April 2012 presents the relatively weak low-level wind speed and distinct diurnal cycle of low-level meteorological fields. The control simulations of both cases represent the systematic overestimation of the low-level wind speed. The positive bias for the case under the baroclinic instability is considerably alleviated by applying the subgrid-scale orography parameterization. However, the improvement of wind speed for the other case showing relatively weak low-level wind speed is not significant. Applying the high-resolution topography and land-use data also improves the simulated wind speed by reducing the positive bias. Our analysis shows that the increased roughness length in the high-resolution topography and land-use data is the key contributor that reduces the simulated wind speed. The simulated wind direction is also improved with the high-resolution data for both cases. Overall, our study indicates that wind forecasts can be improved through the application of the subgrid-scale orography parameterization and high-resolution topography/land-use data.

• Journal of Space Technology and Applications
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• v.1 no.2
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• pp.178-198
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• 2021

The Solar Space Environment Division of the Korean Society of Space Science (KSSS) has recently conducted a survey among the domestic researchers affiliated with academia, national research institutes, and for-profit institutes of how the data and models in their professional research field are produced, maintained, and utilized. The primary purpose of this survey is to increase the awareness and utilization of the space environment data and models as well as to promote constructive collaborations among the domestic and international researchers. The models and data surveyed are categorized into three sub-fields: the solar and interplanetary space, the (terrestrial) magnetosphere, and the ionosphere and upper atmosphere. The present paper reports the survey results in the "Magnetosphere" category. The survey shows that the domestically produced data in this category are far less than the data produced in other categories. This can be understood in part as follows: Magnetospheric research relies heavily on the in-situ observations but the development and operation of space-hardened satellites require a significant investment. Nevertheless, the recent publications show an increasing trend of research using the data from the ground stations and the recently launched domestic space missions. In the modeling front, there are first-principles physics models covering from the magnetospheric scale to the sub-ion scale and the models geared towards the space weather prediction. The detailed survey results can be accessed from the KSSS website (http://ksss.or.kr/).

• Journal of Korea Entertainment Industry Association
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• v.14 no.7
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• pp.333-342
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• 2020

Children grow and develop through play. Play is being used as a friend and a learning material and tool in everyday life of children. It is a research study aimed to empirically analyze the effects of father's play belief and play participation on child's playfulness. A survey was carried out for the selected 284 children aged 5 years and older attending kindergarten located in D-gu, Seoul in order to achieve the goal of this study. Frequency analysis, descriptive statistics, reliability verification, correlation analysis, and regression analysis were conducted on the data collected through the survey by using the SPSS program, and the research results were derived as below. First, it showed that father's play belief and play participation have a positive effect on child's playfulness of physical spontaneity, social spontaneity, cognitive spontaneity, expression of joy, and a sense of humor. Second, father's play participation had a significant effect as a partial parameter in the relationship between father's play belief and child's playfulness. Thus, it was drawn the conclusion that father's play belief and play participation are important variables that can predict child's playfulness. Therefore, It will be necessary to promote children's playfulness development by continuously providing parent education programs on creating an atmosphere of various interaction at home through plays in the relationship between father and child and a desirable role of father in the play activities with child at the level of preschool educational institutions.

• Clean Technology
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• v.28 no.3
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• pp.203-209
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• 2022

An environmental evaluation was conducted by employing LCA methodology for a mechanical seal manufacturing process that uses recycled silicon recovered from end-of-cycle PV modules. The recycled silicon was purified and reacted with carbon to synthesize β-SiC particles. Then the particles underwent compression molding, calcination and heat treatment to produce a product. Field data were collected and the potential environmental impacts of each stage were calculated using the LCI DB of the Ministry of Environment. The assessment was based on 6 categories, which were abiotic resource depletion, acidification, eutrophication, global warming, ozone depletion and photochemical oxidant creation. The environmental impacts by category were 45 kg CO₂ for global warming and 2.23 kg C₂H₄ for photochemical oxide creation, and the overall environmental impact by photochemical oxide creation, resource depletion and global warming had a high contribution of 98.7% based on weighted analysis. The wet process of fine grinding and mixing the raw silicon and carbon, and SiC granulation were major factors that caused the environmental impacts. These impacts need to be reduced by converting to a dry process and using a system to recover and reuse the solvent emitted to the atmosphere. It was analyzed that the environmental impacts of resource depletion and global warming decreased by 53.9% and 60.7%, respectively, by recycling silicon from end-of-cycle PV modules. Weighted analysis showed that the overall environmental impact decreased by 27%, and the LCA analysis confirmed that recycling waste modules could be a major means of resource saving and realizing carbon neutrality.

• Journal of Convergence for Information Technology
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• v.12 no.3
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• pp.158-170
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• 2022

The purpose of this study is to analyze class satisfaction with peer evaluation in Collaborative Learning-based classes. For collaborative learning-based classes, problem-based learning and project-based learning were selected. Educational implications were derived by designing Instructional procedures of Collaborative Learning-based classes, Peer evaluation types and questionnaire design, Peer evaluation progress of Collaborative Learning-based classes, Class satisfaction research and analysis In Collaborative Learning-based classes. The subjects of the study were participants in Collaborative Learning-based classes selected as problem-based learning and project-based classes. For class satisfaction with peer evaluation in Collaborative Learning-based classes, a survey was conducted on 168 participants A University in Korea. The research tool was designed as Learning procedures for peer evaluation Collaborative Learning-based classes is Team Building, Plan to the Task, To do Task, Mid-check on task, Task completion, Presentation & Evaluation, Reflection & Self-Evaluation. The content validity of items was confirmed by CVR of 12 experts. In the research results, the average class satisfaction of peer evaluation is 4.05(SD=91), followed by class concentration, diligence, voluntary, learning atmosphere. As a result of t-testing the difference in class type between collaborate learning-based classes, the satisfaction of PBL was higher than that of PjBL and a statistically significant difference was observed. The result of this study have significance in providing implications for class design and operation for the application and expansion of peer evaluation in higher education. However, there is a limit to generalization as a result of research using convenience.

• The Bulletin of The Korean Astronomical Society
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• v.46 no.2
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• pp.38.2-39
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• 2021

I will presents the analysis of the gas properties of the protoplanetary disk surrounding the young low-mass (about 1.2M_sun) triple star, GG Tau A. This work makes use of ALMA observations of rotational lines of CO (¹²CO, ¹³CO and C¹⁸O) together NOEMA observations of a few dozens of other molecules. While the CO emission gives information on the molecular layer close to the disk atmosphere, its less abundant isotopologues ¹³CO and C¹⁸O bring information much deeper in the molecular layer. I will present the analysis of the morphology and kinematics of the gas disk using the CO isotopologues. A radiative transfer model of the ring in CO isotopologues will also be presented. The subtraction of this model from the original data reveals the weak emission of the molecular gas lying inside the cavity. Thus, I am able to evaluate the properties of the gas inside the cavity, such as the gas dynamics, excitation conditions, and the amount of mass in the cavity. High angular resolution observations of CO reveals sprials induced by embedded planet(s) located near the 3:2:1 mean-motion resonance that help to explain the special morphology of the circumbinary disk. I also discuss some chemical properties of the GG Tau A disk. I report the first detection of H2S and C₂S in a protoplanetary disk. The molecule abundance relative to ¹³CO of about twenties other molecules will also be given. In GG Tau A, the detections of rare molecules such as H₂S and C₂S have been probably possible because the disk is more massive (a factor about 3-5) than other disks where the molecules was searched. Such a large disk mass makes the system suitable to detect rare molecules and to study cold-chemistry in protoplanetary disks.