• Korean journal of applied entomology
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• v.62 no.2
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• pp.69-78
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• 2023

The currently implemented Positive List System, sales manager training, and pesticide sales record systems focus on the safety of determined pesticide use, but the proposed agrochemical pharmacist (AP) system aims accurate diagnosis and reasonable prescription. In this study, 81% of famers claimed expert assistance for purchasing and applying pesticides, and 42~86% of sales managers insisted on the strengthening expertise in diagnosis and prescription. In the institutionalization of AP, a special implementation guideline is essential to embrace the present sales managers with long experience. Sales managers of commercial and agricultural cooperatives recognize the qualifications of agrochemical pharmacists as a strategy to differentiate themselves from competitors, and increase sales through market positioning of "pesticides prescribed by trustworthy agrochemical pharmacists", not sales managers anymore.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.3
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• pp.30-37
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• 2023

The PSCB girder bridge is a closed cross-section in which the top and bottom flanges and the web are integrated, and the structural characteristics are generally different from the bridges in which the girder and the floor plate are separated, so a maintenance plan that reflects the characteristics of the PSCB girder bridge is required. As a result of analyzing damage types by collecting detailed safety diagnosis reports of highway PSCB girder bridges, most of the deterioration and damage occurring during use is concentrated on the top flange. In particular, cracks in the bridge direction on the underside of the top flange occurred in about 70 % of the PSCB girder bridges to be analyzed, and these cracks were judged to be caused by indirect loads such as heat of hydration and drying shrinkage rather than structural cracks caused by external loads. In order to improve durability and reduce maintenance costs of PSCB girder bridges in use, it is necessary to control restraint drying shrinkage cracks from the design stage. Therefore, in this paper, the cracks caused by drying shrinkage under restraint, which is the main cause of cracks under the flanges of the top part of the PSCB girder bridge, were directly calculated using the Gilbert Model, and the influencing factors such as the amount of reinforcing bars, diameter and spacing of reinforcing bars were analyzed. As a result of the analysis, it was found that the crack width caused by restraint drying shrinkage exceeded the allowable crack width of 0.2 mm for reinforcing bars with a reinforcing bar ratio of 0.01 or less based on the H16 reinforcing bar and a reinforcing bar with a diameter greater than H19 based on the reinforcing bar ratio of 0.01. Finally, based on the results of the crack width review, a method for controlling the crack width of the top flange of the PSCB girder bridge was proposed.

• Korean small business review
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• v.41 no.4
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• pp.65-86
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• 2019

This study empirically analyzed how the elements of entrepreneurship and the fear of entrepreneurial failure influence entrepreneurial intention with each other in a situation that encourages startups. In particular, the moderating effect of fear of entrepreneurial failure was verified by dividing the fear of entrepreneurial failure into three sub-variables: fear of financial loss, fear of psychological loss, and fear of career loss. As a result, it was found that proactiveness and risk-taking had a positive effect on entrepreneurial intention, but innovativeness did not. Fear of entrepreneurial failure(all of sub-variables) was found to have no significantly moderating effect on the relationship between entrepreneurship and entrepreneurial intention. Therefore it seemed to have a negative effect as a independent variable. However, considering the regression coefficient(β) is positive or negative depending on the interaction terms of the sub-variables of fear of entrepreneurial failure and the entrepreneurship, it could be inferred that the moderating effect could be positive or negative. Based on this research results, a sophisticated entrepreneurship education program to inspire entrepreneurship and lower the fear of failure is needed in order to promote startups. And at the same time, a social safety net construction plan to reduce the fear of entrepreneurial failure needs to be prepared.

• The Journal of Bigdata
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• v.7 no.1
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• pp.15-27
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• 2022

In the past five years, the fatality rate of single-vehicle accidents has been 4.7 times higher than that of all accidents, so it is necessary to establish a system that can detect and respond to single-vehicle accidents immediately. The IoT(Internet of Thing)-based real-time traffic accident recognition system proposed in this study is as following. By attaching an IoT sensor which detects the impact and vehicle ingress to the guardrail, when an impact occurs to the guardrail, the image of the accident site is analyzed through artificial intelligence technology and transmitted to a rescue organization to perform quick rescue operations to damage minimization. An IoT sensor module that recognizes vehicles entering the monitoring area and detects the impact of a guardrail and an AI-based object detection module based on vehicle image data learning were implemented. In addition, a monitoring and operation module that imanages sensor information and image data in integrate was also implemented. For the validation of the system, it was confirmed that the target values were all met by measuring the shock detection transmission speed, the object detection accuracy of vehicles and people, and the sensor failure detection accuracy. In the future, we plan to apply it to actual roads to verify the validity using real data and to commercialize it. This system will contribute to improving road safety.

• Journal of the Korean Geosynthetics Society
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• v.22 no.4
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• pp.17-26
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• 2023

To consider the risk of damage and fracture of P.C strands, the existing post-maintenance system alone has the limitations, hence it is necessary to quantitatively evaluate and predict the deterioration, durability and safety of facilities and establish a reasonable maintenance system considering the asset value of facilities. Therefore, it is worth considering a preventive maintenance plan that allows proactive measures to be taken before a major defect occurs in the temporary anchor. This study devised a preventive over tension method, reviewed its effectiveness through design and field tests, by calculating the resistance factors by performing a reliability-based optimization design. At this time, the over tension anchor method was evaluated using the ratio of the residual tension force after the fracture of P.C strands to the effective tension force before the fracture of P.C strand, followed by the resistance factor calculated by the optimal solution for each random variables using Excel solver and applying it to the limit state equations. As a result of the study, if the over tension ratio is 125% to 130%, the remaining strands showed a high resistance effect even after the fracture of P.C strand. As a result of the optimization design, it was found that it is appropriate to apply the load factor (γ) of 1.25, and the resistance factors of Φ₁, Φ₂, Φ₃ as 0.7, 0.5, 0.6.

• Journal of Environmental Impact Assessment
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• v.32 no.5
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• pp.338-352
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• 2023

As of 2019, Korea's fine dust is the most severe among 38 OECD countries, and in the same year, 「the Framework on Disaster and Safety Management」 was revised to define fine dust as a social disaster. Currently, the government is working to achieve its emission reduction goals by preparing a comprehensive fine dust management plan (2022-2023) consisting of a total of five areas, 42 tasks, and 177 detailed tasks. However, it is necessary to come up with measures in consideration of the various spatial characteristics of the city, not just as a source of emission. Therefore, in this study, the shape of the city was classified using the LCZ (Local Climate Zone) classification system into 17 types by building type and land cover type in Busan, and the average annual PM10 and PM2.5 concentration were mapped using the IDW technique. In addition, Fragstats and Moving Window were used to quantify the LCZ classification system. Finally, correlation analysis and regression analysis were conducted to analyze the relationship between the LCZ classification system and PM10 and PM2.5. As a result, it was confirmed that the type of low height of the building and the type of green space with trees had a positive effect on the concentration of PM10 and PM2.5. Therefore, this study is expected to be used as basic data to establish fine dust reduction policies based on efficient spatial planning.

• Korean Chemical Engineering Research
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• v.61 no.4
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• pp.496-504
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• 2023

Countries worldwide are striving to find new sources of sustainable energy without carbon emission due to the increasing impact of global warming. With the advancement of the fourth industrial revolution on a global scale, there has been a substantial rise in energy demand. Simultaneously, there is a growing emphasis on utilizing energy sources with minimal or zero carbon content to ensure a stable power supply while reducing greenhouse gas emissions. In this comprehensive overview, a comparative analysis of carbon reduction policies of government was conducted. Based on international carbon neutrality scenarios and the presence of remaining thermal power generation, it can be categorized into two types: "Rapid" and "Safety". For the domestic scenario, the projected power demand and current greenhouse gas emissions in alignment with "The 10th Basic Plan for Electricity Supply and Demand" was examined. Considering all these factors, an overview of the current status of carbon neutrality technologies by focusing on the energy sector, encompassing transitions, hydrogen, transportation and carbon capture, utilization, and storage (CCUS) was offered followed by summarization of key technological trends and government-driven policies. Furthermore, the central aspects of the domestic carbon reduction strategy were proposed by taking account of current mega trends in the energy sector which are highlighted in international scenario analyses.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.6
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• pp.55-61
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• 2023

In this study, a basic research was conducted to establish a maintenance plan considering the environmental factors and deterioration characteristics of port facilities. The precise safety diagnosis reports for Incheon and Busan port facilities were referenced to examine the extent of deterioration and damage. The relationship with the degradation environmental assessment presented in the current guidelines was also analyzed. The analysis of the damage level of Incheon and Busan port facilities revealed that Incheon Port exhibited approximately three times higher damage rate compared to Busan Port. In the case of Incheon Port, reinforcement corrosion and external damage showed similar proportions, while in Busan Port, reinforcement corrosion had a higher proportion compared to external damage. On the other hand, when comparing with the degradation environmental assessment presented in the guidelines, it was found that there were some limitations in performing quantitative evaluation based on the guidelines for assessing port facilities. Therefore, an analysis based on tidal range was conducted by referring to existing literature. The analysis of tidal range in Incheon and Busan regions showed that Incheon had approximately five times higher difference compared to Busan. It is considered that this can be utilized as a differentiated item from existing degradation environmental assessment criteria.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.6
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• pp.689-693
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• 2023

Domestic bridges with a service life of more than 30 years are expected to account for approximately 54% of all bridges within the next 10 years. As bridges rapidly deteriorate, it is necessary to establish an appropriate maintenance plan. Recent domestic and international research have focused on the integration of BIM to digitize bridge maintenance information and then enhance accessibility and usability of the information. Accordingly, this study developed a BIM-FEM interoperability algorithm for bridge decks to convert maintenance information into data and efficiently manage the history of maintenance. After creating an initial crack BIM based on an exterior damage map, bridge specification and damage information were linked to a numerical analysis that performs damage analysis considering damage scenarios and design loads. The spread of cracks obtained from the analysis results were updated into the BIM. Based on the damage spread information on the BIM, an automated technology was also developed to assess both the current and future condition ratings of the bridge deck. This approach can enable an efficient maintenance of the deck using the history data from bridge inspection and diagnosis as well as future information on cracks and defects. The expected early detection and prevention would ultimately improve the lifespan and safety of bridges.

• Journal of the Korean Institute of Gas
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• v.27 no.4
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• pp.70-77
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• 2023

In response to climate change, each country is proposing a goal to reduce greenhouse gases in its energy supply and demand plan, and the use of hydrogen gas is a topic that is always prioritized as an energy resource for implementation. A popular way to use this hydrogen gas is the use of hydrogen fuel cell vehicles, and expansion of hydrogen charging stations is essential for using these hydrogen fuel cell vehicles. However, there are several limitations to the expansion of hydrogen refueling stations, the most representative of which is resident acceptance. Most of the hydrogen charging stations currently built in Korea are located in the outskirts with low population density, so the inconvenience to hydrogen fuel cell vehicle users has not been resolved, and as a result, there has been no progress in the spread of hydrogen fuel cell vehicles. In this paper, we analyzed the consequences of accident damage to determine the risks of constructing a hydrogen charging station on a railroad site frequently used by citizens. The target hydrogen charging station site was a railroad depot in Busan, and there are trains, national highways, and commercial facilities around this site. Assuming the worst-case scenario, we would like to consider the safety of the hydrogen refueling station site by analyzing the area affected by the accident and its consequence.