• Nuclear Engineering and Technology
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• v.54 no.5
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• pp.1674-1685
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• 2022

The ball valve is an important device in the pipeline transportation system of nuclear power plants. Its operational stability and safety directly affect the normal working of nuclear power plants. In this study, the transient numerical simulation of the opening and closing process of a ball valve was conducted on the basis of the flow interruption capability experiment of the ball valve by using the moving mesh method and inlet and outlet variable boundary conditions. The flow rate and pressure difference with time of the opening and closing process of the ball valve were studied. The internal flow characteristics of the ball valve under different relative openings were analyzed in conjunction with the typical back-step flow structure. Results show that the transient numerical results agree well with the experimental results. The internal flow characteristics of the ball valve are similar at the same opening during opening and closing process. At small opening, the spool and outlet channels easily form a back-step flow structure. The disappearance and generation of backflow vortices during opening and closing occur at 85% opening and 75% opening, respectively. With the decrease in opening degree, the difference in vortex core area in the flow channel of the ball valve spool in the opening and closing process gradually appears. The research results provide some reference value for the design and optimization of ball valves.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.32 no.5
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• pp.891-898
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• 2022

Along with global interest, drones are expanding the base of utilization such as transportation of goods, forest protection, and safety management, and cluster flights are being applied in various fields such as military operations and environmental monitoring. Currently, specialized networks such as e-UM 5G for services in specific industries are being established in Korea. In this regard, drone systems are also moving to establish specialized networks to provide services that are fused with AI and autonomous flight. As drones converge with various services, various security threats in various environments are also subordinated, and in response, requirements and guidelines for drone security are being prepared in Korea. In this paper, we propose a technology method for peer identification and safe information provision between cluster flight drones by utilizing a cryptographic module equipped with wireless LAN and quantum entropy-based random number generator in a cluster flight system and a mobile communication network such as e-UM 5G.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.21 no.6
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• pp.165-176
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• 2022

In order to prevent various accidents with construction machinery, Korea enacted the Construction Machinery Management Act to enhance safety. Until now, there has been a lack of systematic research related to traffic accidents with construction machinery. Therefore, domestic and foreign systems related to construction machinery were reviewed, and the current status was analyzed based on traffic accident data over the past 5 years to derive implications. It is necessary to ensure the safety of construction machinery by correcting institutional loopholes and preparing follow-up measures. In addition, it is necessary to create a separate traffic-safety education program for construction machinery operators to create an environment that can comply with safe road-driving methods and traffic laws.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.23 no.1
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• pp.1-12
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• 2024

Pedestrian facilities encompass pedestrian roads, stairs, and queuing areas exclusively designed for pedestrian use. The Korean Highway Capacity Manual provides guidelines for analyzing the capacity and level of service of pedestrian facilities. However, there is a lack of analysis methods tailored specifically for pedestrian facilities. Therefore, in this study, we introduced a new standard of pedestrian space to account for changes in the Korean body ellipse. Furthermore, based on this newly defined pedestrian space, we proposed a new standard value for the level of service of queuing areas. The results of on-site surveys confirmed that the proposed level of service can effectively reflect the actual walking situation.

• Journal of the Korea Society of Computer and Information
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• v.29 no.3
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• pp.1-10
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• 2024

The research on predicting the routes of ships, which constitute the majority of maritime transportation, can detect potential hazards at sea in advance and prevent accidents. Unlike roads, there is no distinct signal system at sea, and traffic management is challenging, making ship route prediction essential for maritime safety. However, the time intervals of the ship route datasets are irregular due to communication disruptions. This study presents a method to adjust the time intervals of data using appropriate interpolation techniques for ship route prediction. Additionally, a deep learning model for predicting ship routes has been developed. This model is an LSTM model that predicts the future GPS coordinates of ships by understanding their movement patterns through real-time route information contained in AIS data. This paper presents a data preprocessing method using linear interpolation and a suitable deep learning model for ship route prediction. The experimental results demonstrate the effectiveness of the proposed method with an MSE of 0.0131 and an Accuracy of 0.9467.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.1
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• pp.39-46
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• 2020

Accident prevention is more important than follow-up, which is based on Heinrich's law. The marine incident system is a very meaningful system that can prevent similar accidents, and was introduced in 2010 in Korea in accordance with the enforcement of the Code for the Investigation of Marine Casualties and Incidents (CI Code). Based on the CI Code, ship owners or ship operators are required to notify the Central Chief Inspector using the designated notification form in the event of a marine incident, but the number of voluntary notifications is still small. In this regard, this study intends to provide a direction for improvement by conducting an in-depth analysis focusing on the lack of notification procedures and forms of the marine incident system. To this end, we analyzed related regulations, cases of excellent overseas shipping countries such as the United Kingdom and Singapore, cases of similar domestic transportation systems such as aviation and railways, and marine incident notification procedures and forms of leading shipping companies. Major improvements in the notification process include the transition of the marine incidents to voluntary reporting, the expansion of the reporting subjects, and the identification of the security of the informer's identity. The main contents of the notification form revision include the use of the term "reporting" instead of "notification," the content of the identity guarantee in the notification form, and the increase in statistical value through the expansion of optional entries.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.4
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• pp.582-587
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• 2020

Recently, disasters caused by extreme weather and the damage caused by them are increasing worldwide. The interest in disasters, such as earthquakes, typhoons, and ground subsidence, is increasing in Korea. Korea has enacted a special law based on disaster management, and has built monitoring systems for individual facility units by building precision sensors and related systems to measure the displacement status of long bridges and high-rise composite buildings. On the other hand, the application of a real-time monitoring system is insufficient for slopes, open-pit mines, small and medium structures due to weather, measurement methods, cost, and constant monitoring difficulties. In this study, the displacement monitoring method using the total station was studied and the applicability was suggested through the experiment. Through the research, the concept and operation flow of a monitoring system that can measure the displacement of the terrain or the structure using the total station was presented. The monitoring system allows the user to select the location and operation method of the equipment so that the equipment can be installed according to the site situation, and set the number of observations, the period, and the observation range of the object. Using the experiment on the monitoring system, the station was monitored with precision within 5mm, and it was suggested that the displacement of the object can be monitored using the total station. Further research will be needed to assess the applicability of monitoring to real slopes and structures.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.7
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• pp.841-850
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• 2019

The Korean government has designated speed-limit zones and speed limits in 19 ports and 3 routes to ensure safe navigation and transportation. However, the speed limit differs from port to port, no practical means of management exist. This often leads to violation of the speed limit. Additionally, ship collisions due to human error continue to occur. First, the study analyzed marine accidents that occurred at trade ports and fairways. The result of the analysis revealed the occurrence of 1344 accidents (average 269 cases per year) from 2014 to 2018. Five hundred sixty three accidents involved fishing boats, whereas, merchant vessels were involved in 508 cases. Second, the efficacy of the application of voice and message warnings to GPS plotters and electronic chart display and information system (ECDIS) was reviewed, and these were proposed as measures to inform vessel operators of the hazards of speed limit violation. Third, experts' opinions from relevant agencies and navigation system manufacturers were consulted and it was found that the proposed warning function was technically implementable. The findings are expected to help reduce human error among ship operators and establish a Korean e-navigation system.

• The Journal of the Korea Contents Association
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• v.21 no.7
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• pp.259-270
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• 2021

Recently, interests in the use of Sharing Bike is increasing in consideration of eco-friendly transportation and safety from viruses. As the technology for collecting and storing data is improved with the development of ICTs, research on mobility using the Sharing Bike Data is also actively progressing. Therefore, this paper analyzes the properties of Sharing Bike Data and cases of researches on it through literature review, and based on the results of the review, data of Eoulling, the Sharing Bike System of Sejong City is analyzed as a way to utilize Sharing Bike Data. Most of the selected literature used structured data, and analyzed it through statistical methods or data mining. Through data analysis, it identified the current status, found out problems of the Sharing Bike System, proposed a solution to solve them, developed plans to activate the use of Sharing Bike. This provides basic data for efficient management and operation plans for Sharing Bike System. Ultimately, it will be possible to explore ways to improve mobility in urban spaces by utilizing Sharing Bike Data.

• Journal of the Society of Disaster Information
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• v.18 no.1
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• pp.202-217
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• 2022

Purpose: The recent increased use of Personal Mobility (PM) has been accompanied by a rise in the annual number of accidents. Accordingly, the safety requirements for PM use are being strengthened, but the laws/systems, infrastructure, and management systems remain insufficient for fostering a safe environment. Therefore, this study comprehensively searches the main problems and improvement methods through a review of previous studies that are related to PM. Then the priorities according to the importance of the improvement methods are presented through the Delphi survey. Method: The research method is mainly composed of a literature study and an expert survey (Delphi survey). Prior research and improvement cases (local governments, government departments, companies, etc.) are reviewed to derive problems and improvements, and a problem/improvement classification table is created based on keywords. Based on the classification contents, an expert survey is conducted to derive a priority improvement plan. Result: The PM-related problems were in 'non-compliance with traffic laws, lack of knowledge, inexperienced operation, and lack of safety awareness' in relation to human factors, and 'device characteristics, road-drivable space, road facilities, parking facilities' in relation to physical factors. 'Management/supervision, product management, user management, education/training' as administrative factors and legal factors are divided into 'absence/sufficiency of law, confusion/duplication, reduced effectiveness'. Improvement tasks related to this include 'PM education/public relations, parking/return, road improvement, PM registration/management, insurance, safety standards, traffic standards, PM device safety, PM supplementary facilities, enforcement/management, dedicated organization, service providers, management system, and related laws/institutional improvement', and 42 detailed tasks are derived for these 14 core tasks. The results for the importance evaluation of detailed tasks show that the tasks with a high overall average for the evaluation items of cost, time, effect, urgency, and feasibility were 'strengthening crackdown/instruction activities, education publicity/campaign, truancy PM management, and clarification of traffic rules'. Conclusion: The PM market is experiencing gradual growth based on shared services and a safe environment for PM use must be ensured along with industrial revitalization. In this respect, this study seeks out the major problems and improvement plans related to PM from a comprehensive point of view and prioritizes the necessary improvement measures. Therefore, it can serve as a basis of data for future policy establishment. In the future, in-depth data supplementation will be required for each key improvement area for practical policy application.