• Korean Journal of Soil Science and Fertilizer
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• v.31 no.1
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• pp.51-55
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• 1998

The experiment was conducted to elucidate the growth response of rice seedling to heavy metals, copper and zinc. The copper and zinc concentration in rice seedling was 50mg/l and 100mg/l, respectively. Germination. chlorophyll and organic compounds were investigated in seedling of rice with or without heavy metals. Root growth and germination were inhibited at 50mg/l Cu and at 100mg/l compared to control and such reduction in growth was more remarkable at 100mg/l Zn than at 50mg/l Cu. Chlorophyll content was slightly reduced at both 50mg/l Cu and 100mg/l Zn. Malic acid was remarkably increased at 50mg/l Cu compared with that at Zn 100mg/l regardless of rice cultivars. The content of organic acids such as succinic, citric, and malic acid and free proline was increased with treatment of copper and zinc.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.6
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• pp.731-736
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• 2021

Oil fences effectively prevent the spread of oil spilled in the sea, thereby reducing the damage to the marine environment. However, the fence is damaged by oil and structures at the accident site and is discarded. When incinerated disposal method for discarded fences, fine dust, and harmful materials are generated. Moreover, as a part of the damaged fence is dumped into the sea, it may cause secondary environmental pollution, such as microplastics. Therefore, in this study, durability was measured using the most common solid foam type oil fences. As a result, the reduction rate of after five days of contact was 13 % in seawater and 3 % in oil, affected by temperature changes. Thus, the durability of the fence should be improved because it is exposed to seawater and oil and affected by wind, light, and waves depending on the weather conditions. Therefore, we suggest a method to improve the oil fence inspection to strengthen the durability of the fence's fabric part.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.31 no.5
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• pp.1001-1010
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• 2021

Smart factories are complex systems which combine latest information technology (IT) with operation technology (OT). A smart factory aims to provide manufacturing capacity improvement, customized production, and resource reduction with these complex technologies. Although the smart factory is able to increase the efficiency through the technologies, the security level of the whole factory is low due to the vulnerability transfer from IT. In addition, the response and restoration of the business continuity plan are insufficient in case of damage due to the absence of factory security experts. The cope with the such problems, we propose an information security practice content for analyzing the damage by generating ransomware attacks in a digital twin-based smart factory similar to the real world. In our information security content, we introduce our conversion technique of physical devices into virtual machines or simulation models to build a practical environment for the digital twin. This content generates two types of the ransomware attacks according to a defined scenario in the digital twin. When the two generated attacks are successfully completed, at least 8 and 5 of the 23 virtual elements are take damage, respectively. Thus, our proposed content directly identifies the damage caused by the generation of two types of ransomware in the virtual world' smart factory.

• Korean Journal of Remote Sensing
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• v.37 no.5_3
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• pp.1435-1446
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• 2021

Wind and flood damage caused by typhoons causes a lot of damage to the Korean Peninsula every year. In order to minimize damage, a preliminary analysis of damage estimation and evacuation routes is required for rapid decision-making. This study attempted to develop an analysis module that can provide necessary information according to the disaster stage. For use in the preparation stage, A function to check past typhoon routes and past damage information similar to typhoon routes heading north, a function to extract isolated dangerous areas, and a function to extract reservoir collapse areas were developed. For use in the early stages of response and recovery, a function to extract the expected flooding range considering the current flooding depth, a function to analyze expected damage information on population, buildings, farmland, and a function to provide evacuation information were included. In addition, an automated web map creation method was proposed to express the analysis results. The analysis function was developed and modularized based on Python open source, and the web display function was implemented based on JavaScript. The tools developed in this study are expected to be efficiently used for rapid decision-making in the early stages of monitoring against storm and flood damage.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.4
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• pp.545-553
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• 2021

The frequency by water disaster in urban areas are increasing continuously due to climate change and urbanization. Countermeasures are being conducted to reduce the damage caused by water disasters. An analysis based on permeability, one of the parameters that affect runoff, is needed to predict quantitative runoff in urban watersheds and study runoff reduction. In this study, the SWAT model was simulated for the oncheon stream basin, a representative urban stream in Busan. The permeability map was prepared by calculating the CN values for each hydrologic response unit. Based on the permeability map prepared, EPA SWMM analyzed the effect of LID technology application on the water cycle in the basin for short-term rainfall events. The LID element technology applied to the oncheon stream basin was rooftop greening in the residential complex, and waterproof packaging was installed on the road. The land cover status of the land selected based on the permeability map and the application of LID technology reduced the outflow rate, peak flow rate, and outflow rate and increased the infiltration. Hence, LID technology has a positive effect on the water cycle in an urban basin.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.3
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• pp.513-519
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• 2019

Typically, contaminated sediments cause clogging of the drain pipe, which increases the residual water pressure in the drain pipe; this study constructed a system for improving drainage efficiency of tunnels by reducing physical and chemical obstructions through ultrasonic energy generated by a PVDF film. The developed hybrid drainage system utilized a PVDF material film fused with an existing drainage tunnel and maintenance system resulting in the ability to initialize the reverse piezoelectric effect, which was evaluated through an on site application. In order to investigate the maintenance performance of the tunnel drainage system, contaminated sediments were simulated in a drainage pipe to test the effect of ultrasonic conditions on drainage efficiency in the laboratory. As a result of applying the developed portable equipment, the ultrasonic energy was generated for about 20 minutes resulting in a reduction of 74.62% of the contaminated sediments and improving drainage efficiency. From the tunnel, acoustic pressure measurements were taken to calculate the response rate while taking into account the laboratory results. In addition, PVDF film was attached to the transverse and longitudinal side of the drainage pipes where contaminated sediments occur most often in the field tunnel. these calculations show contaminant removal was 90% effective.

• Korean Journal of Clinical Laboratory Science
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• v.50 no.4
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• pp.470-476
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• 2018

Facial motor evoked potential (FMEP) by multi-pulse transcranial electrical stimulation (mpTES) can complement free-running electromyography (EMG) and direct facial nerve stimulation to predict the functional integrity of the facial nerve during cerebello-pontine angle (CPA) tumor surgery. The purpose of this paper is to examine the standardized test methods and the usefulness of FMEP as a predictor of facial nerve function and to minimize the incidence of facial paralysis as an aftereffect of surgery. TES was delivered through electrode Mz (cathode) - M3/M4 (anode), and extracranially direct distal facial muscle excitation was excluded by the absence of single pulse response (SPR) and by longer onset latency (more than 10 ms). FMEP from the orbicularis oris (o.oris) and the mentalis muscle simultaneously can improve the accuracy and success rate compared with FMEP from the o.oris alone. Using the methods described, we can effectively predict facial nerve outcomes immediately after surgery with a reduction of more than 50% of FMEP amplitude as a warning criterion. In conclusion, along with free-running EMG and direct facial nerve stimulation, FMEP is a useful method to reduce the incidence of facial paralysis as a sequela during CPA tumor surgery.

• Journal of Microbiology and Biotechnology
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• v.29 no.7
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• pp.1083-1095
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• 2019

Butyrate is known to play a significant role in energy metabolism and regulating genomic activities that influence rumen nutrition utilization and function. Thus, this study investigated the effects of an isolated butyrate-producing bacteria, Clostridium saccharobutylicum, in rumen butyrate production, fermentation parameters and microbial population in Holstein-Friesian cow. An isolated butyrate-producing bacterium from the ruminal fluid of a Holstein-Friesian cow was identified and characterized as Clostridium saccharobutylicum RNAL841125 using 16S rRNA gene sequencing and phylogenetic analyses. The bacterium was evaluated on its effects as supplement on in vitro rumen fermentation and microbial population. Supplementation with $10^6CFU/ml$ Clostridium saccharobutylicum increased (p < 0.05) microbial crude protein, butyrate and total volatile fatty acids concentration but had no significant effect on $NH_3-N$ at 24 h incubation. Butyrate and total VFA concentrations were higher (p < 0.05) in supplementation with $10^6CFU/ml$ Clostridium saccharobutylicum compared with control, with no differences observed for total gas production, $NH_3-N$ and propionate concentration. However, as the inclusion rate (CFU/ml) of C. saccharobutylicum was increased, reduction of rumen fermentation values was observed. Furthermore, butyrate-producing bacteria and Fibrobacter succinogenes population in the rumen increased in response with supplementation of C. saccharobutylicum, while no differences in the population in total bacteria, protozoa and fungi were observed among treatments. Overall, our study suggests that supplementation with $10^6CFU/ml$ C. saccharobutylicum has the potential to improve ruminal fermentation through increased concentrations of butyrate and total volatile fatty acid, and enhanced population of butyrate-producing bacteria and cellulolytic bacteria F. succinogenes.

• The Journal of the Korea Contents Association
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• v.18 no.11
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• pp.1-12
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• 2018

Heat waves during summer cause a qualitative degradation in urban environments and increases the number of patients who suffer from heat-related illnesses, and the urbanization deepens these problems. It is a prerequisite to analyze the current status accurately in order to assess the urban heat island phenomenon. Thus, this study aims to collect weather measurements information at the occurrence of a severe heat wave in Seoul, thereby allowing analysis of information, which will also consider the land use type. The weather measurement information used in the analysis had an advantage, as the gap between measured locations is considerably shorter than before due to the miniaturization of the automatic weather systems (AWS), which are connected through the communication network. Based on the above collected information, a temporal change in the data due to land use type was analyzed. As a result, the difference in temperature change in response to the land use type could be compared, as could the occurrence pattern of the tropical night phenomenon, and the effect on temperature reduction in green belt areas could be identified through the comparison of the intensity of heat island by time and land use. The methods and results derived in this study through the comparative analysis in terms of time and land use, weather information measurements, and mapping can be utilized as foundational data that can be referred to in urban planning to reduce the heat island phenomenon in the future.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.9
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• pp.175-181
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• 2019

In the case of a conventional single stage decompression regulator used for large depressurization in the hydrogen fuel cell system of a fuel cell electric vehicle (FCEV), problems can arise, such as pulsation, slow response, hydrogen brittleness, leakage, high weight, and high cost due to high decompression. Most of these problems can be overcome easily using two decompression mechanisms (two-stage structures). In addition, a wide outlet-pressure control range can be secured if an electronic solenoid is applied to the second decompression. Accordingly, it is necessary to improve the precision of the outlet pressure of a two-stage pressure-reducing regulator and develop techniques, such as leakage prevention, durability, light weight, and price reduction. Therefore, to improve the outlet pressure accuracy and prevent leakage, the structural part before and after decompression to improve the air tightness were divided and the analysis was carried out assuming that the valve part was closed (open ratio: 0%) after each initial internal pressure application.