• Journal of the Korean Recycled Construction Resources Institute
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• v.8 no.4
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• pp.520-527
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• 2020

Hwangtoh is the rich resource that accounts for about 15.0% of the domestic soil, and can be used as the admixture of concrete with Pozzolan characteristics if activated by rapidly freezing after burning with high temperature. In this study, the mortar curbs containing active hwangtoh were produced, based on the mixture for the mortar curbs sold on the market. The substitution rate of active hwangtoh were considered 10.0% and 25.0%, and the test items were selected to compressive and flexural strength tests, freezing/thawing resistance tests, accelerated carbonation tests, and accelerated chloride diffusion tests. In the results of the mechanical performance, it was showed that the highest strength was evaluated in OPC mixture, and the increase in strength was small by the increase of age, which was believed to be due to the fact that most of the strength in each mixture was created in three days of steam curing. The results of the freezing/thawing tests for 28 aged days showed the reduction rate of compressive strength was 85.0% or higher for all specimen, meeting the criteria presented. The accelerated carbonation tests were carried out on the specimen at 28 days of age, and the results showed that the mortar with active hwangtoh had lower carbonation resistance performance than mortar with OPC. The passed charge of each mixture was assessed in accordance with ASTM C 1202 on 28 and 91 aged days. The OPC mixture had "Low" rate and the mortar with active hwangtoh had "Moderate" rate. So it was thought that the mortar with active hwangtoh had appropriate resistance performance for chloride attack.

• Journal of the Korean Recycled Construction Resources Institute
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• v.8 no.4
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• pp.506-513
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• 2020

In this study, the mechanical properties, absorption, and reduction performance of NOx in the mortar containing mineral admixture like zeolite and active hwangtoh were evaluated. Zeolite and active hwangtoh were used as binder, and zeolite and active hwangtoh were substituted for cement. The substitution ratio of two types of mineral admixtures was considered as 20 and 30% respectively. As a result of evaluating the compressive strength and flexural strength of each mortar specimen, the highest strength in the plain mixture was evaluated. As the substitution ratio of zeolite and active hwangtoh increased, the compressive and flexural strength decreased. In addition, the difference of compressive and flexural strength between active hwangtoh and zeolite mixing was evaluated to be insignificant. To evaluate the absorption rate, the mixture was designed to lower the W/B ratio of the existing mixture and set the substitution ratio of active hwangtoh and zeolite at 25%. The highest absorption ratio in the mortar with zeolite was evaluated, and the difference in absorption ratio between the remaining two mortar mixtures was small. The assessment of reduction performance of NOx considering the application of photocatalyst showed a clearly decreasing reduction behavior, even if they were the same mortar mixture. Zeolite and active hwangtoh also showed a higher NOx reduction than the Plain mixture, because of their porosity properties. In the case of active hwangtoh, the absorption ratio was lower than that of zeolite mixture, but the reduction of NOx performance was better than the result of zeolite mixture.

• KIPS Transactions on Computer and Communication Systems
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• v.10 no.3
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• pp.71-80
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• 2021

The selection of an appropriate neural network algorithm is an important step for accurate data prediction in machine learning. Many algorithms based on basic artificial neural networks have been devised to efficiently predict future data. These networks include deep neural networks (DNNs), recurrent neural networks (RNNs), long short-term memory (LSTM) networks, and gated recurrent unit (GRU) neural networks. Developers face difficulties when choosing among these networks because sufficient information on their performance is unavailable. To alleviate this difficulty, we evaluated the performance of each algorithm by comparing their errors and processing times. Each neural network model was trained using a tax dataset, and the trained model was used for data prediction to compare accuracies among the various algorithms. Furthermore, the effects of activation functions and various optimizers on the performance of the models were analyzed The experimental results show that the GRU and LSTM algorithms yields the lowest prediction error with an average RMSE of 0.12 and an average R2 score of 0.78 and 0.75 respectively, and the basic DNN model achieves the lowest processing time but highest average RMSE of 0.163. Furthermore, the Adam optimizer yields the best performance (with DNN, GRU, and LSTM) in terms of error and the worst performance in terms of processing time. The findings of this study are thus expected to be useful for scientists and developers.

• Journal of Digital Convergence
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• v.20 no.4
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• pp.529-539
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• 2022

This study analyzed the index change in efficiency and productivity for the tax reorganization project of the regional headquarters of Korea Asset Management Corporation using panel data for 3 years from 2017 to 2019 using the DEA-Malmquist analysis model. According to the DEA analysis result, the average of the efficiency by the CCR model of the regional headquarters tax reorganization project of the Korea Asset Management Corporation was 0.671 in 2017, 0.772 in 2018, and 0.699 in 2019, and the average of the efficiency by the BCC model was 0.798 in 2017, 0.851 in 2018 and 0.771 in 2019. As a result of analyzing the Malmquist productivity index, the time series average productivity index MPI increased by 4.5%. These results appear to be attributable to the increase in technological efficiency, technological change, and scale-efficiency change rather than the decrease in net efficiency change. Looking at the change in MPI by year, it decreased by 14.6% in 2017-2018, but increased significantly to 27.8% in 2018-2019. Through the results of DEA analysis of specific tax projects of public corporations, each regional headquarters of Korea Asset Management Corporation will be able to contribute to reinforcing business capabilities through mutual benchmarking.

• Journal of the Korean earth science society
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• v.43 no.1
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• pp.176-187
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• 2022

Due to recent mid-scale earthquakes in the Korean Peninsula, the Korean central and local governments are preparing new measures for earthquake hazard mitigation. Geological and geotechnical information is essential for earthquake hazard assessment. Thus, related data have been collected and assimilated as DBs by various national organizations. However, several problems arise when local governments intend to use this information to establish earthquake hazard mitigation measures. In the case of the geological information, small-scale geological maps make it difficult to acquire detailed information, whereas lithofacies and faults do not often match at the boundaries of large-scale geological maps. Significant geotechnical information is lost due to lack of digitalization. Present study proposes four policy plans for geological and geological information management. First, it is necessary to link industry-academictechnology fields to use the information that has already been or to be produced more efficiently and professionally. Second, local government regulations are required to be enacted and revised to accumulate a lot of geological and geotechnical information. Third an expert system should be prepared to improve the quality of the information. Fourth, it is necessary to establish a dedicated department and expand budget support for efficient information management.

• The Korean Journal of Food And Nutrition
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• v.34 no.6
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• pp.612-620
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• 2021

To increase the utilization of Centella asiatica (CA), enzymes such as cellulase and pectinase were added and the physicochemical properties of the treated CA were analyzed. In addition, apple-CA jam was prepared using the enzyme-treated CA, which had the best antioxidant properties, and the physicochemical and sensory qualities of the jam were measured. There was a high content of ascorbic acid, polyphenols, flavonoids, reducing sugar, amino acid, minerals and DPPH radical scavenging activity in the enzyme-treated group. The antioxidant component and activity in the jam prepared by adding enzyme-treated CA increased with an increase in the amount of enzyme-treated CA. In the soluble solids, the higher the amount of enzyme-treated CA, the higher the value, but there was no significant difference in pH. The sensory evaluation of the jam, in particular the taste, showed that the highest preference was observed when the enzyme-treated CA was added in the range of 5.0~6.7%, and the control group showed the lowest preference. There was no significant difference in flavor and spreadability among the treatment groups, however, the control group showed the highest color preference. In the overall acceptability, when 5.0% of enzyme-treated CA was added, the highest acceptability was shown.

• Journal of Ginseng Culture
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• v.4
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• pp.59-102
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• 2022

Since there were only few countries that could find wild ginseng grown in nature, the culture of digging wild ginseng was only developed in a small number of countries. In a time when the orthodox head-Simmemani has disappeared, the tangible and intangible culture of Simmemani (wild ginseng digger) is disappearing more and more with the passage of time. So far, the conducted research on wild ginseng diggers was very partial and simplistic as follows: ① Research on the argot of Simmemani, ② Research on the customs of Simmemani, ③ Research on the change of customs of Simmemani, ④ Additional records through interview with Simmemani. Accordingly, no comprehensive study on the Simmemani culture has been done yet. This study supplements the historical materials that were not reflected in previous studies, and discuss on diverse subjects including the definition and classification of wild ginseng, the distribution of wild ginseng and Simmemani, interpretation of wild ginseng digging from a legal and social point of view, the organization responsible for the digging, determination of the date of entering the mountain, preparations, taboos, departure and entry into a mountain, religious events, psalmbook, dream interpretation, search and discovery of wild ginseng, digging, profit sharing, the amount of harvested wild ginseng, and the price of wild ginseng. In addition, Korean wild ginseng digging culture was comprehensively studied by attaching the photos and illustrations of historical documents with the psalmbook of the head-Simmemani.

• Journal of Life Science
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• v.32 no.6
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• pp.438-446
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• 2022

Some flowers have a high sensual appeal owing to their unique shape, color, smell, and taste and have been used as functional food and oriental medicine. Recently, edible dry flowers (EDFs) have attracted social attention as noble sources of functional teas. In this study, for the risk assessment of EDFs, pathogenic bacteria, heavy metals, and pesticide residues were monitored in 23 types of commercial EDF. No Enterobacteria spp. and Listeria spp. were found in all EDF products. However, common aerobic bacteria (3.24~3.85 Log CFU/g) were found in EDF, namely, Pueraria lobata, Chamaemelum nobile, Acacia decurrens, Rhododendron mucronulatum Turcz, Oenothera lamarckiana, Brassica napus, and Prunus serrulata. Staphylococcus aureus was found in 11 and Salmonella sp. was found in 8 of the 23 EDFs. Considering the cold extraction of EDF for tea and beverages, the regulation of pathogenic bacteria in EDFs is necessary. No heavy metals such as Pb, Cd, Co, Cr, Cu, Ni, and As were found in all EDFs, except the dry flower of Hemerocallis fulva, which contained Pb at 0.08 ppm. Different pesticides and fungicides were found in EDFs, but their concentrations were very low (0.01~0.08 ppm) and below the maximal residue level. Only the dry flower of Chrysanthemum morifolium had a high content of chlorpyrifos (0.215 ppm), which is long-lasting pesticide. Our results suggest that the establishment of EDF regulations for pesticide residue, culture separation between edible and garden flowers, and guidelines for preventing pathogenic microbial contamination are necessary.

• Korean Journal of Heritage: History & Science
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• v.55 no.2
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• pp.186-197
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• 2022

The Daejanggakgibi Stele of Silleuksa Temple in Yeoju is a stone stele from the Goryeo Dynasty that is inscribed with various stories about the construction of Daejanggak, a place where Buddhist scriptures were kept. This stele has been maintained for a long time in a state in which discoloration of the body has occurred, and the inscription has been partially damaged due to dozens of cracks. Using non-destructive analysis methods for stone artifacts, material investigation, portable X-ray fluorescence analysis, and ultrasonic velocity analysis for the stele were performed. It was confirmed that the stele body was composed of light gray crystalline limestone, and the base stone, support stone, and cover stone were medium-grained biotite granite. Portable X-ray fluorescence analysis confirmed that iron(Fe) was an original coloring element of the stele surface. From the distribution pattern of the coloration, it can be inferred that iron-containing materials flew down from between the stele body and the cover stone. Thereafter, living organisms or organic contaminants attached to it so that yellow and black contaminants were formed. Ultrasonic diagnosis revealed that the physical property of both the front and back surfaces ranged from fresh rocks(FR) to completely weathered rocks(CW), and the average weathering index was grade 3(intermediate). However, the point where cracks developed intensively was judged to be the completely weathered stage(CW), and some cracks located in the upper and lower parts of the stele bear potentially very high risk. It is necessary to monitor the movement of these cracks and establish reinforcement measures for conservation in the future.

• Journal of Practical Agriculture & Fisheries Research
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• v.23 no.1
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• pp.49-57
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• 2021

As the world marks the adoption of the landmark Paris Agreement on climate change, a promising movement for carbon neutrality is taking shape. This agreement would be needed to build a truly global coalition for carbon neutrality by 2050. Greenhouse gas(GHGs) emissions from agriculture come from livestock such as cows, agricultural soils and rice production has been reported by 10% in 2019. Rice cultivation would be reduced a GHGs and thus this research has conducted to minimize the emission of greenhouse gas with the mulching methodology using a biodegradable film in dry hill seeded rice and to conserve the environment through a cultural and ecological weed control instead of chemicals. We have developed the 5^th mulching dry hill seeder with the biodegradable film to determine the possibility of stable rice cultivation. There were so many difficulties and constraints in the field operations such as film mulching, hill seeding and effective weed control. The mulching dry hill seeder was so good performance in the 5^th trial but the biodegradable film tested was so faster in terms of biodegradation before the heading stage of the rice plant and thus there was not highly effective weed control which is ongoing research with a good performance since 2020.