• Journal of the Korean Recycled Construction Resources Institute
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• v.10 no.3
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• pp.204-210
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• 2022

Cement is pointed out as the main cause of carbon dioxide emission in the construction industry. Many researchs are underway to use blast furnace slag, an industrial by-product, as a substitute for cement to reduce carbon dioxide emitted during the manufacturing the cement. When blast furnace slag is used as a substitute for cement, it has advantages such as long-term strength and chemical resistance improvement. However, blast furnace slag has a problem that makes initial strength low. This is due to the impermeable film on the surface created during the production of blast furnace slag. The created film is known to be destroyed in an alkaline environment, and based on this, previous studies have suggested a solution using various alkali activators. But, alkali activator is dangerous product since it is a strong alkaline material. And it has the disadvantage in price competitiveness. In this study, an experiment was conducted to improve the initial hydration reactivity of the blast furnace slag to secure the initial strength of the mortar substituted with the blast furnace slag and to check whether the carbonation resistance was increased. As a result of the experiment, it was confirmed that the mortar using alkaline water showed higher strength than the mortar using tap water, and there were more hydration products generated inside. In addition, it was confirmed that the mortar using alkaline water as a compounding water had high carbonation resistance.

• Korean Journal of Food Science and Technology
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• v.53 no.4
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• pp.501-508
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• 2021

The purpose of this study was to evaluate the application of ATP bioluminescence assay for effect assessment of hygiene visiting education on children's foodservice facilities in the local small town. The sanitary inspection results of the hygiene visiting education showed significant improvement in all items except 'To regularly disinfect cooking facilities, storage rooms, etc.' ATP bioluminescence analysis was performed on cooking utensils to evaluate the educational effect, and the results showed a correlation with the effect in most items. In the case of knives and cutting boards, all facilities showed a value of 20 RLU/cm² or less after the educational support, and in particular, it was approximately 10 RLU/cm² or less in national/public, corporation and private facilities. Correlation analysis between the post-education sanitary inspection results and ATP values for three items related to knives and cutting boards showed that they have a negative and high correlations.

• The Korea Journal of Herbology
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• v.28 no.1
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• pp.91-96
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• 2013

Objectives : Obesity is a chronic metabolic disease caused by disorder of energy balance and lipid metabolism. This study was conducted by histopathology and histomorphometry to investigate the anti-obesity effects of mixed water extract of Plantaginis Semen & Poria (CJB) on liver, epididymal fat pads and pancreas zymogen granules in obese rats induced with high fat diet. Method : Male Sprague-Dawley rats to be divided four groups were fed into four different treatments: normal (NOR) diet, high-fat (HF) diet, HF diet+CJB (100 mg/kg and 300 mg/kg, P.O.) for 8 weeks. The weekly body weights were measured in four experimental groups, respectively. Also histopathological and histomorphometrical changes of liver, epididymal fat pads and pancreas zymogen granules were observed in normal control and obese rats, respectively. Results : Adminstration of CJB significantly reduced body weights compared to those of HF group for experimental period. After 8 weeks, liver weights in the CJB groups were lower than those of HF group. In addition, HF diet related steatohepatitis, adipocyte hypertrophy, exocrine disturbances (decreases of pancreatic zymogen granules) were also dose-dependently inhibited by treatment of test material, CJB 100 and CJB 300 as compared with HF group, respectively. Conclusion : Based on the results, it is considered that CJB will be showed hepatoprotective and anti-obese effects, may be directly and/or indirectly mediated by pancreatic zymogen granules because they dose-dependently inhibited steatohepatitis, hypertrophy of adipocytes and decreases of pancreatic zymogen granules induced by HF diet supply, respectively.

• Journal of Korea Water Resources Association
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• v.55 no.12
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• pp.1053-1064
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• 2022

The Thiessen method, which is the current area average precipitation method, has serious structural limitations in accurately calculating the average precipitation in the watershed. In addition to the observation accuracy of the precipitation meter, errors may occur in the area average precipitation calculation depending on the arrangement of the precipitation meter and the direction of the heavy rain. When the watershed is small and the station density is sparse, in both simulation and observation history, the Thiessen method showed a peculiar tendency that the average precipitation in the watershed continues to increase and decrease rapidly for 10 minutes before and after the peak. And the average precipitation in the Thiessen basin was different from the rainfall radar at the peak time. In the case where the watershed is small but the station density is relatively high, overall, the Thiessen method did not show a trend of sawtooth-shaped over-peak, and the time-dependent fluctuations were similar. However, there was a continuous time lag of about 10 minutes between the rainfall radar observations and the ground precipitation meter observations and the average precipitation in the basin. As a result of examining the ground correction effect of the rainfall radar watershed average precipitation, the correlation between the area average precipitation after correction is rather low compared to the area average precipitation before correction, indicating that the correction effect of the current rainfall radar ground correction algorithm is not high.

• Korean journal of applied entomology
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• v.61 no.1
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• pp.267-274
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• 2022

Portable and vehicle thermal fogs were tested using etofenprox, bifenthrin, and deltamethrin diluted with diesel oil, kerosene, and water against domestic vector mosquitoes, Aedes albopictus, Anopheles sinensis s.l., Culex pipiens, and Culex tritaeniorhynchus. The female mosquitoes were confined in small cages suspended on poles at progressively greater distances from the fog release point at an open field. The average mortality rates of four vector mosquitoes to the three insecticides were 52.0% and 64.0% at a portable thermal fogs diluted with diesel oil and water within a 10 m distance, respectively. A vehicle thermal fog had a mean mortality of 34.8% of the females to the insecticides diluted with diesel oil within 50 m. The mortality rates were not significantly different among all the tested distances. At a dilution solvent test, the mortality of the females to the insecticides diluted with kerosene was 1.9 times higher than that of diesel oil.

• The Journal of Engineering Geology
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• v.32 no.4
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• pp.597-610
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• 2022

Knowledge of the failure behavior of friction materials considering their intermediate principal stress is related to an understanding of situations where these materials might be used: for example, the stability of deep-seated boreholes and fault slip analysis. This study designed equipment for physically implementing true triaxial compression and used it to assess specimens of plaster, a friction material. The material's mechanical behaviors are discussed based on the results. The applicability of the 3D failure criteria are also reviewed. The tested specimens were molded cuboids of width, length, and height 52, 52, and 104 mm, respectively. A total of 24 true triaxial compression tests were performed under various combinations of 𝜎₃ and 𝜎₂ conditions. Conventional uniaxial and triaxial compression tests were employed to estimate the mechanical properties of the plaster for use as parameters for 3D failure criteria. Examining the stress-strain relations of the plaster materials showed that a large difference between the intermediate principal stress and the minimum principal stress indicated strong brittle behavior. The mechanical behavior of the plaster used here reflects the change of intermediate principal stress. Nonlinear multiple regression analysis on the test data in the principal space showed that the modified Wiebols-Cook failure criterion and the modified Lade failure criterion were the most suitable 3D failure criteria for the tested plaster.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.34 no.3
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• pp.82-92
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• 2022

In recent years, coastal and port structures have attempted to prevent wave-overtopping or provide waterfront areas by installing superstructures on the structural crowns. In general, in the design stage, the Goda formula acting on the front the structure is applied to calculate the wave pressure acting on the superstructure in consideration of the wave-runup of the design wave. However, the wave pressure exceeding the Goda wave pressure could generate depending on the installation location of the superstructure where the wave-overtopping occurs. This study analyzed the applicability of the Goda formula to the wave pressure calculation for the superstructure of the vertical structures through hydraulic model experiments and numerical simulations. Furthermore, this study investigated the magnitude of the wave pressure acting on the superstructure based on detailed numerical results. As a result, the wave pressure acting on the superstructure was up to 120% higher than the maximum wave pressure on the still water surface. In addition, the wave pressure increases exponentially with the Froude number computed by the overtopping water depth at the crown of the structure, and we proposed an empirical formula for predicting the wave pressure based on the Froude number.

• Journal of Science Education
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• v.46 no.3
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• pp.293-311
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• 2022

In this study, a restriction enzyme mapping inquiry experiment was developed for cultivating basic knowledge on molecular biology and the effects on inquiry experiment ability and positive experience on science through student-centered molecular biology inquiry experiment class for second graders of a general high school was analyzed. First of all, it was found that the experimental class through the inquiry experiment was significantly effective as the percentage of high school students who answered 'yes' or higher in the positive science experience of general high school students was higher after than before the test. As a result of developing and applying a series of five classes for the creation of restriction enzyme maps, not only did the students' interest in science studies, but also their class participation increased. They were also used as effective specific science learning motives, science career aspirations and experience data. The science environment of the inquiry experiment class led to the improvement of students' learning attitudes and positive science experience, which had a positive effect on the importance of class concentration and class quality, active communication and mutual cooperation among students. In addition, inquiry and experiment classes will provide opportunities for career experience, which will become the foundation for cultivating basic knowledge on molecular biology and advancing to science and engineering.

• 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 the Society of Disaster Information
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• v.19 no.3
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• pp.498-509
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• 2023

Purpose: This paper proposes a method detecting the falling of a maintenance worker in the underground utility tunnel, by applying deep learning techniques using CCTV video, and evaluates the applicability of the proposed method to the worker monitoring of the utility tunnel. Method: Each rule was designed to detect the falling of a maintenance worker by using the inference results from pre-trained YOLOv5 and OpenPose models, respectively. The rules were then integrally applied to detect worker falls within the utility tunnel. Result: Although the worker presence and falling were detected by the proposed model, the inference results were dependent on both the distance between the worker and CCTV and the falling direction of the worker. Additionally, the falling detection system using YOLOv5 shows superior performance, due to its lower dependence on distance and fall direction, compared to the OpenPose-based. Consequently, results from the fall detection using the integrated dual deep learning model were dependent on the YOLOv5 detection performance. Conclusion: The proposed hybrid model shows detecting an abnormal worker in the utility tunnel but the improvement of the model was meaningless compared to the single model based YOLOv5 due to severe differences in detection performance between each deep learning model