• Journal of Applied Biological Chemistry
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• v.64 no.2
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• pp.159-164
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• 2021

Heavy metals exist in soils in various chemical forms including free metal ions and organo-metal complexes. The ratio of free metal ions has been known to be highly associated with the plant absorption of heavy metals. This study aims to understand the effect of free ions and organo-metal complexes on the absorption of lead (Pb) and cadmium (Cd) by plants. For this, lettuce grown in a hydroponic system for 28 days was consequently grown another 48 hours using Pb and Cd solutions. The ratios of free ion to organo-metal complexes in the solutions were adjusted at 100:0, 90:10, 70:30, 60:40 by four different organic acids (citric, oxalic, acetic, and humic acid). After that, the concentration of Pb and Cd in lettuce were analyzed. The Pb and Cd absorption by lettuce was more relied on the types of organic acids treated and the type of metals rather than the ratio of free metal ions. For example, citric acid increased the Pb absorption while it decreased the Cd absorption by lettuce. There was no significant relationship between free metal ion ratios and both Pb and Cd uptake by lettuce. It could be explained that citric acid, a relatively higher molecular weight organic acid, has higher ion binding capacity, so it forms organo-Pb complex easily due to the higher affinity of Pb on the binding site in comparison with Cd. Consequently, this complexation would assist Pb uptake by lettuce.

• Applied Chemistry for Engineering
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• v.32 no.1
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• pp.20-27
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• 2021

Effects of the etching treatment of SAPO-34 catalyst were investigated to improve the catalytic lifetime in DTO reaction. The aqueous NH3 solution was a more appropriate treatment agent which could control the degree of etching progress, compared to that of using a strong acid (HCl) or alkali (NaOH) solution. Therefore, the effect on characteristics and lifetime of SAPO-34 catalyst was observed using the treatment concentration and time of aqueous NH3 solution as variables. As the treatment concentration or time of aqueous NH3 solution increased, the growth of erosion was proceeded from the center of SAPO-34 crystal plane, and the acid site concentration and strength gradually decreased. Meanwhile, it was found that external surface area and mesopore volume of SAPO-34 catalyst increased at appropriate treatment conditions. When the treatment concentration and time were 0.05 M and 3 h, respectively, the lifetime of the treated SAPO-34 catalyst was the longest, and was significantly enhanced by ca. 36% (based on DME conversion of > 90%) compared to that of using the untreated catalyst. The model for the etching progress of SAPO-34 catalyst in a mild treatment process using aqueous NH3 solution was also proposed.

• Journal of The Korean Association of Information Education
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• v.24 no.5
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• pp.511-518
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• 2020

Preparing for the Fourth Industrial Revolution and Corona-19, our education is expanding a new chapter of learning to the era of AI education that incorporates software technology beyond software education. In this study, we will analyze the case of learner-centered assessment in software education and examine the assessment direction of artificial intelligence education through its effectiveness. Through the case of applying learner-centered assessment to non-computer subjects including computer subjects, we sought the effects on learners' learning, environmental conditions and assessment models of learner-centered evaluation, and through the case of applying the learner-centered assessment model to software education, we wanted to find out what the learner-centered assessment in artificial intelligence education suggests to the educational site. According to the analysis, the learner-centered assessment had a significant effect on the learner's achievement goal, and it is expected that the learner-centered assessment in artificial intelligence education will be carried out smoothly when an objective evaluation system and objective evaluation model are designed to help the learner's assessment, building digital environment conditions based on intelligent information technology.

• Journal of the Korean Association of Geographic Information Studies
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• v.24 no.1
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• pp.26-39
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• 2021

This study investigated the characteristics of the watershed and pollutants in the Seonakdong River basin in the lower stream of the Nakdong River Water System, and evaluated the areas vulnerable to nonpoint pollution by subwatershed according to the TOPSIS(Technique for Order of Preference by Similarity to Ideal Solution) method. The selection method consists of selection of evaluation factors, calculation of weights and selection of areas vulnerable to non-point pollution through evaluation factors and weights. The entropy method was used as the weight calculation method and TOPSIS, a multi-criteria decision making(MCDM) method was used as the evaluation method. Indicator data were collected as of 2018, and national pollution source survey data and national statistics were used. Most of the vulnerable watersheds were highly urbanized had a large number of residents and were evaluated as having a large land area among industrial facilities and site area rate. Through this study, it is necessary to approach a variety of weighting methodologies to assess the vulnerability of non-point pollution with high reliability, and scientific analysis of the factors that affect non-point pollution sources and consideration of the effects are necessary.

• Journal of Korean Society of Disaster and Security
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• v.13 no.4
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• pp.75-92
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• 2020

In most cases of the water balance analysis, the return flow ratio for each water supply was uniformly determined and applied, so it has been contained a problem that the volume of available water would be incorrectly calculated. Therefore, sewage and wastewater among the return water were focused in this study and the data-driven model was developed to forecast the outflow from the sewage treatment plant. The forecasting results of LSTM (Long Short-Term Memory), GRU (Gated Recurrent Units), and SVR (Support Vector Regression) models, which are mainly used for forecasting the time series data in most fields, were compared with the observed data to determine the optimal model parameters for forecasting outflow. As a result of applying the model, the root mean square error (RMSE) of the GRU model was smaller than those of the LSTM and SVR models, and the Nash-Sutcliffe coefficient (NSE) was higher than those of others. Thus, it was judged that the GRU model could be the optimal model for forecasting the outflow in sewage treatment plants. However, the forecasting outflow tends to be underestimated and overestimated in extreme sections. Therefore, the additional data for extreme events and reducing the minimum time unit of input data were necessary to enhance the accuracy of forecasting. If the water use of the target site was reviewed and the additional parameters that could reflect seasonal effects were considered, more accurate outflow could be forecasted to be ready for climate variability in near future. And it is expected to use as fundamental resources for establishing a reasonable river water management system based on the forecasting results.

• The Journal of the Korea Contents Association
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• v.21 no.5
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• pp.695-706
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• 2021

The purpose of this study was to establish entrepreneurship(risk taking, proactiveness, innovativeness), entrepreneurial self-efficacy, and entrepreneurial intention as a structural equation model to confirm the entrepreneurial intention of university students. In order to achieve the purpose of this study, 449 students from 3 university students in Gyeonggi-do were studied, and data analysis was conducted with SPSS 23.0 and AMOS 23.0 statistical programs. The results of the empirical analysis are as follows: First, Among university students' entrepreneurship, proactiveness was not statistically significant to entrepreneurial intention but, risk taking and innovativeness have been identified as having a direct impact. Second, University students' entrepreneurial self-efficacy directly affects entrepreneurial intention. Third, risk taking and innovativeness were statistically significant, but proactiveness was not affected. Finally, through the mediating of entrepreneurial self-efficacy, risk taking effects were fully sold to entrepreneurial intention, and innovativeness was partially sold to entrepreneurial intention. Based on the results of this study, the way to enhance university students' entrepreneurial intention is to develop programs that can improve their entrepreneurial self-efficacy and apply them actively to university education. In particular, university students need mentoring support from on-site entrepreneurial experts and internship education support to increase risk taking and innovativeness as prospective founders. The government can lead to entrepreneurial behavior when economic and institutional support precedes university students to recover from their initial entrepreneur.

• Journal of the Korean Institute of Gas
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• v.25 no.6
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• pp.7-13
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• 2021

Various research has been done on fires and explosions at gas stations at home and abroad. However, only studies of off-site damage in the event of fire at the gas station were conducted, and research on fire at the auxiliary facilities in the gas station was insufficient. The gas station is a place where anyone can easily access dangerous goods. As the risk of fire increases due to the recent increase of auxiliary facilities such as convenience stores and car repair shops in gas stations, it is important to detect the effects of fire on the main oil refinery in case of fire and to verify the validity of existing regulations. In this thesis, we conducted a study to find out the effect of radiation heat on the separation between fixed and fixed oil reactors in the event of fire at an auxiliary facility. Simulation was modelled using FDS 5.5.3 Version, and the size of the fire source was configured with 13 fire assessment devices and the heat emission rate per unit area was entered. Simulation shows that the separation distance of 2 m does not secure the safety of the gas pump in the event of fire at the auxiliary facilities, and radiation heat does not damage at the separation distance of at least 4 m. Accordingly, facilities that can block radiant heat in the event of fire at auxiliary facilities, and measures to limit the use of auxiliary facilities or to re-impose the separation between buildings and fixtures will be needed.

• Land and Housing Review
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• v.13 no.1
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• pp.1-9
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• 2022

In 1991, the United Nations World Tourism Organization (UNWTO) declared "tourism accessible for all" recommending the practice of the right to enjoy tourism. According to the Ministry of Health and Welfare of Korea (2019), the disabled, who are the most vulnerable in tourism, accounted for 5.1% of the total population, and the number of the elderly over 65 is expected to increase to 20.3% by 2025. In particular, the need for customized policies has been raised as the proportion of disabled people among the elderly aged 65 and over continues to increase. Thus, this study identified the spatial characteristics of Universal Design (UD) tourist destinations considering the tourism vulnerable groups. Administrative units (425 dongs) in Seoul were used as spatial units for analysis. As a research method, first, a spatial model was specified through LM verification, and then spatial regression analysis was performed. As a result of the analysis, the spatial characteristics of UD tourist destinations were found to have positive (+) effects on the number of universally certified businesses, the number of restaurants, and the number of bus stops that were available to the vulnerable. It was confirmed that there are a large number of universal certified businesses, restaurants, and bus stops in dongs with UD tourist destinations. The findings will provide policy implications when promoting the right to enjoy tourism in the future and improving Korean universal design quality.

• The Journal of the Korea Contents Association
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• v.22 no.7
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• pp.149-163
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• 2022

With the development of the culture industry, online transactions of cultural products are being activated, and offering information and establishing relationship with customers in web-site have an important influence on online purchase decision making. The purpose of this research is to examine the effect of information and relational benefits provided by online sales sites of cultural products on online purchasing intention, and to reveal through empirical analysis whether these influences show a difference between stage products and screen products. Looking at the results of the study, first, in the case of the whole, both information offering and relational benefits have a significant effect on online purchasing intention. Second, in the case of stage products(plays), product understanding information, economic relational benefits, and customization relational benefits showed significant effects, but product purchasing information showed no significant influence. Third, in the case of screen products(movies), product purchasing information and economic relational benefits showed a significant effect, but product understanding information and customization relational benefits had no significant effect. In conclusion, the impact of information offering and relational benefits on online purchasing intention differs according to cultural products, and economic relational benefit is found to be an important influencing factor on online purchase decision making in all cases. These research results are expected to be helpful in establishing differentiated marketing strategies including customer relationship management in online transactions of cultural products.

• Journal of Korean Society of Rural Planning
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• v.27 no.4
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• pp.55-70
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• 2021

In this study, in the field of remote sensing, where the scope of application is rapidly expanding to fields such as land monitoring, disaster prediction, facility safety inspection, and maintenance of cultural properties, monitoring of rural space and surrounding environment using UAV is utilized. It was carried out to verify the possibility, and the following main results were derived. First, the aerial image taken with an unmanned aerial vehicle had a much higher image size and spatial resolution than the aerial image provided by the National Geographic Information Service. It was suitable for analysis due to its high accuracy. Second, the more the number of photographed photos and the more complex the terrain features, the more the point cloud included in the aerial image taken with the UAV was extracted. As the amount of point cloud increases, accurate 3D mapping is possible, For accurate 3D mapping, it is judged that a point cloud acquisition method for difficult-to-photograph parts in the air is required. Third, 3D mapping technology using point cloud is effective for monitoring rural space and rural resources because it enables observation and comparison of parts that cannot be read from general aerial images. Fourth, the digital elevation model(DEM) produced with aerial image taken with an UAV can visually express the altitude and shape of the topography of the study site, so it can be used as data to predict the effects of topographical changes due to changes in rural space. Therefore, it is possible to utilize various results using the data included in the aerial image taken by the UAV. In this study, the superiority of images acquired by UAV was verified by comparison with existing images, and the effect of 3D mapping on rural space monitoring was visually analyzed. If various types of spatial data such as GIS analysis and topographic map production are collected and utilized using data that can be acquired by unmanned aerial vehicles, it is expected to be used as basic data for rural planning to maintain and preserve the rural environment.