• Industry Promotion Research
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• v.8 no.4
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• pp.37-46
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• 2023

Due to the aging, advancement, and complexity of chemical facilities, non-routine work such as facility inspection, repair, or maintenance work is increasing. Of the 1,483 accidents that occurred over the past 10 years at chemical product manufacturing sites subject to PSM, accidents that occurred during non-routine work accounted for 56% (932 Cases) of the total. It can be seen that more accidents occur during non-routine work than during routine work. In particular, in order to improve the economy and efficiency of factory operation, there are cases where some facilities are stopped without stopping the entire factory and then inspection, repair, or maintenance work is performed while isolated from the operating facilities. Therefore, first, a safe isolation method must be selected by establishing an isolation standard (Baseline Isolation Standard) based on the chemicals handled, operating conditions, and risk level of the equipment in the chemical plant. Second, since current domestic laws and standards do not suggest the need for specific quarantine standards, it is necessary to institutionalize the preparation of quarantine standards. Technical and institutional improvements are needed to prevent fires, explosions, and poisoning accidents caused by leaks of chemical substances.

• Clean Technology
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• v.29 no.4
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• pp.297-304
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• 2023

The rapid advancement of the high-tech electronics industry has led to a significant increase in high-concentration ammonia wastewater. Various methods have been attempted to reliably treat wastewater containing high concentrations of ammonia, but no successful technology has yet been developed and applied. In this study, the removal efficiency and characteristics of ammonia nitrogen was evaluated according to changes in temperature, air loading rate, and liquid loading rate using a closed circulation countercurrent packed tower type demonstration facility for wastewater containing high concentrations of ammonia generated in the high-tech electronics industry. The temperature was varied while maintaining operating conditions of a wastewater flowrate of 20.8 m³ h^-1 and an air flow rate of 18,000 Nm³ h^-1. The results showed that at temperatures of 45,50,55, and 60℃, the removal efficiencies of ammonia nitrogen (NH₃-N) were 87.5%, 93.4%, 96.8%, and 98.7%, respectively. It was observed that temperature had the most significant impact on the removal efficiency of NH₃-N under these conditions. As the air loading rate increases, the removal rate also increases, but the increase in removal efficiency is not significant because droplets from the absorption tower flow into the stripping tower. Even if the liquid loading rate was changed by ±30%, the removal rate did not change significantly. This does not mean that the removal rate was unaffected, but was believed to be due to the relatively high air load rate. Through demonstration research, it was confirmed that ammonia stripping is a reliable technology that can stably treat high-concentration ammonia wastewater generated in the high-tech electronics industry.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.6
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• pp.735-747
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• 2023

In recent times, the sharp increase in extreme flood damages due to climate change has posed a challenge to effectively address flood-related issues solely relying on conventional flood management infrastructure. In response to this problem, this study aims to consider the effectiveness of nature-based flood management approaches, specifically levee retreat and relocation. To achieve this, we utilized a 1D numerical model, HEC-RAS, to analyze the flood reduction effects concerning floodwater levels, flow velocities, and time-dependent responses to a 100-year frequency flood event. The analysis results revealed that the effect of creating a flood buffer zone of the nature-based solution extends from upstream to downstream, reducing flood water levels by up to 30 cm. The selection of the flow roughness coefficient in consideration of the nature-based flood buffer space creation characteristics should be based on precise criteria and scientific evidence because it is sensitive to the flood control effect analysis results. Notably, floodwater levels increased in some expanded floodplain sections, and the reduction in flow velocities varied depending on the ratio of the expanded cross-sectional area. In conclusion, levee retreat and floodplain expansion are viable nature-based alternatives for effective flood management. However, a comprehensive design approach is essential considering flood control effects, flow velocity reduction, and the timing of peak water levels. This study offers insights into addressing the challenges of climate-induced extreme flooding and advancing flood management strategies.

• Journal of the Korea institute for structural maintenance and inspection
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• v.28 no.3
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• pp.100-107
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• 2024

Currently, in Korea, due to the rapid aging and deterioration of facilities, the minimum Maintenance Level and Performance Level' of facilities are required by the 'Facility Safety Act' or 'Infrastructure Management Act'. Since infrastructure assets have a long lifespan and the pattern of deterioration over time is complex, it is very difficult to maintain infrastructure as 'minimum maintenance state' or 'minimum performance state' by the current way of management. 'Asset Management' shall be performed not only by a technical perspective, but also by an accounting perspective such as cost and asset value. However, due to lack of awareness of 'asset management' among stakeholder, only technical perspective management is being carried out in practice. In order to effectively manage infrastructure assets, complex consideration of various asset value factors such as budget and service as well as safety and durability are required. In this paper, we presented a theory to evaluate and quantify the road network value for efficient asset management of the road network. We also presented a method of simulation to apply the theory presented in this paper. Through simulation and the results derived from this study, it is possible to specify the budget for the future national asset management, and to optimize the strategy for the management of old road facilities.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.44 no.1
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• pp.101-108
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• 2024

The total number of railroad stations managed in Korea is 322 (including general and wide-area railways), and a considerable number of stations are aging. In terms of the size of the existing railway station and the number of entrances, it has not been possible to secure adequate service capacity, and the demand for station improvement is increasing due to changes in surrounding conditions such as urban development. In the past, railroad stations were focused on the simple function of a connection passage in terms of maintenance or management, but in recent years, railroad stations are also changing to an atmosphere that they should be reborn as a user-centered comfortable, convenient, and safe service provision space. In this study, a case study related to the improvement of the old railway station was conducted to derive an improvement plan that meets the improvement standard of the old station, and the service level evaluation standard was developed. By introducing the concept of service level (LOS) in the development model, station congestion, station movement convenience, and station safety were selected as evaluation indicators. In addition, this development model applied an analytical stratification technique to divide various evaluation elements of each indicator into major and detailed elements and derive the relative importance of the elements by class. Priority for improvement was derived using the ratio of the number of E and F on the LOS for each facility. Based on this study, it is expected to be helpful in using it as an evaluation criterion for improving objective and equitable railway station.

• Smart Media Journal
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• v.13 no.2
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• pp.68-84
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• 2024

This paper describes the development of a system and algorithms for high-quality welfare services by recognizing behavior development indicators (activity, sociability, danger) in children aged 0 to 2 years old using action recognition technology. Action recognition targeted 11 behaviors from lying down in 0-year-olds to jumping in 2-year-olds, using data directly obtained from actual videos provided for research purposes by three nurseries in the Gwangju and Jeonnam regions. A dataset of 1,867 actions from 425 clip videos was built for these 11 behaviors, achieving an average recognition accuracy of 97.4%. Additionally, for real-world application, the Edge Video Analyzer (EVA), a behavior analysis device, was developed and implemented with a region-specific random frame selection-based PoseC3D algorithm, capable of recognizing actions in real-time for up to 30 people in four-channel videos. The developed system was installed in three nurseries, tested by ten childcare teachers over a month, and evaluated through surveys, resulting in a perceived accuracy of 91 points and a service satisfaction score of 94 points.

• Land and Housing Review
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• v.15 no.1
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• pp.39-55
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• 2024

The aim of this study is to analyse housing satisfaction among residents of different types of public rental housing-permanent, national, and happy housing-following the integration of housing types upon the full-scale supply of integrated public rental housing. By identifying key factors that influence residential satisfaction, our goal is to inform the planning of public rental housing complexes and derive policy implications. The study focuses on analysing discrepancies in residential satisfaction among residents of different types of public rental housing and comparing the factors influencing this satisfaction. Microdata from the Ministry of Land, Infrastructure, and Transport's 'Housing Situation Survey' in 2021 is utilized for analysis, employing one-way ANOVA and binomial logistic regression methods. Empirical analysis reveals variations in residential satisfaction levels between residents of permanent and national rental housing, with national rental housing residents exhibiting higher satisfaction. The influencing factors of overall condition satisfaction are consistent for permanent and national rental residents but differ for happy housing residents. Additionally, the influencing factors of overall residential environmental satisfaction vary across all three housing types. Nonetheless, common factors across all types include housing noise and facility accessibility, highlighting their significance in complex planning. Subsequent studies may involve time series analysis to assess changes in influencing factors over time.

• Journal of Korean Tunnelling and Underground Space Association
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• v.25 no.6
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• pp.479-493
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• 2023

The need for safety management has arisen due to the increasing number of years of operated underground structures, such as tunnels and utility tunnels, and accidents caused by those aging infrastructures. However, in the case of privately managed underground utility ducts, there is a lack of detailed guidelines for facility safety and maintenance, resulting in inadequate safety management. Furthermore, the absence of basic design information and the limited space for safety assessments make applying currently used non-destructive testing methods challenging. Therefore, this study suggests non-destructive inspection methods using ultrasonic and impact-echo techniques to assess the quality of underground structures. Thickness, presence of rebars, depth of rebars, and the presence and depth of internal defects are assessed to provide fundamental data for the safety assessment of box-type general underground structures. To validate the proposed methodology, different conditions of concrete specimens are designed and cured to simulate actual field conditions. Applying ultrasonic and impact signals and collecting data through multi-channel accelerometers determine the thickness of the simulated specimens, the depth of embedded rebar, and the extent of defects. The predicted results are well agreed upon compared with actual measurements. The proposed methodology is expected to contribute to developing safety diagnostic methods applicable to general underground structures in practical field conditions.

• Journal of Cadastre & Land InformatiX
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• v.54 no.1
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• pp.19-32
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• 2024

This study examined the feasibility of image-based surveys by detecting objects in facilities and agricultural land using the YOLO algorithm based on drone images and comparing them with the land category by law. As a result of detecting objects through the YOLO algorithm, buildings showed a performance of detecting objects corresponding to 96.3% of the buildings provided in the existing digital map. In addition, the YOLO algorithm developed in this study detected 136 additional buildings that were not located in the digital map. Plastic greenhouses detected a total of 297 objects, but the detection rate was low for some plastic greenhouses for fruit trees. Also, agricultural land had the lowest detection rate. This result is because agricultural land has a larger area and irregular shape than buildings, so the accuracy is lower than buildings due to the inconsistency of training data. Therefore, segmentation detection, rather than box-shaped detection, is likely to be more effective for agricultural fields. Comparing the detected objects with the land category by law, it was analyzed that some buildings exist in agricultural and forest areas where it is difficult to locate buildings. It seems that it is necessary to link with administrative information to understand that these buildings are used illegally. Therefore, at the current level, it is possible to objectively determine the existence of buildings in fields where it is difficult to locate buildings.

• Journal of Cadastre & Land InformatiX
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• v.54 no.1
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• pp.75-87
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• 2024

There There is a difference in terms of administrative power in that the address of things are not an address under Public Act. In terms of location expression, it is possible to express the location more flexibly and in more detail than the road name address, so it should be improved so that it can be assigned and managed in an appropriate location, so that the location of the entire territory can be expressed together with the road name address. As a result of the comparison between the road name address and the address of things based on the analysis results of related laws such as the existing Road Name Address Act, the Building Act, and the Regulations on the Preparation and Management of Basic Address Information, it was confirmed that there are fundamental limitations of the address of things system. Accordingly, this study attempted to suggest ways to improve the address of thing system by broadly dividing it into the legal aspect and the addressable object aspect. From the legal point of view, firstly, it is necessary to improve the upper and lower level laws by unification together with a clear definition of the term subject of addressable object; secondly, according to the Building Act, facilities that are not used for residence among buildings must be given an address of thing; and thirdly, it is necessary to make it easy to use and link with heterogeneous public data by classifying the registration items of the basic address information map by type of geographical feature to be assigned an address. From the point of view of addressability, firstly, it must be given to all facilities in the relevant category so that it can be recognised that all specific facilities have object addresses, and secondly, it is necessary to be able to address the address of things to places that are used by many, even if there are no facilities.