• Korean Journal of Construction Engineering and Management
• /
• v.24 no.3
• /
• pp.31-41
• /
• 2023

This study is a study to develop a configuration management methodology for efficient and systematic management in the event of configuration changes such as deformation, explosion, and remodeling of launch vehicle development test facilities, which are emerging as important national facilities in the era of full-scale space competition. Through the analysis of international standards for configuration management, a configuration management process framework to be applied to launch vehicle development test facilities is extracted, a survey was conducted on experts who performed life cycle engineering of launch vehicle development test facilities, and a configuration management methodology optimized for operation/management of domestic launch vehicle development test facilities was proposed. Identify the configuration for launch vehicle development test facilities, the configuration management manager, configuration management organization, and configuration management board approve/process the configuration changes, and after construction is completed according to design requirements, launch vehicle development test facilities try to manage the configuration in a controlled state.

• Journal of Advanced Navigation Technology
• /
• v.27 no.5
• /
• pp.519-527
• /
• 2023

Air-launch means launching from aircraft such as fighter jets, and has various advantages, such as cost reduction and less environmental/weather impact during launch. However, there are no air-launch satellite in Korea. Examining air-based launch satellite and anti-satellite missiles operated and developed by foreign private companies and various countries confirmed the necessity of domestic research and development. In South Korea, various research activities, including satellite launch system design and development approaches for different launch platforms, have been carried out mainly by academia. Development of upward maneuver air launch technology which is launched in the air when the aircraft is moving upward is suggested. Additionally, an introduction to wind tunnel tests for safety separation verification is provided. A new concept for a test facility has been suggested to conduct drop tests.

• Journal of Navigation and Port Research
• /
• v.48 no.1
• /
• pp.1-6
• /
• 2024

Aid-to-Navigation facility is important for maritime traffic safety. In Korea, for safe maritime traffic, the Ministry of Oceans and Fisheries is using an Aid-to-Navigation management system. The current Aid-to-Navigation management system displays information based on text, making it difficult to determine the impact if Aid-to-Navigation fails or an accident occurs. A simulator can be used to verify the placement of Aid-to-Navigation. However, real-time information is not applied and maintenance of the simulator is expensive. Additionally, the Aid-to-Navigation simulator cannot simulate effects of port backlighting. To improve these issues, we proposed an Aid-to-Navigation management platform based on digital twin technology. This system can predict failures by analyzing real-time sensor data collected from navigation signs. We plan to develop a function that can simulate Aid-to-Navigation placement. Aid-to-Navigation is expected to be managed efficiently by applying digital twin technology.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.44 no.3
• /
• pp.375-383
• /
• 2024

The size of the construction industry is increasing, and its impact on the entire national industry is also significant. However, construction cost increases, construction period delays, safety accidents, and quality problems occur during the construction process. This paper analyzed the construction cost, construction period, and change order performance for civil infrastructures for which post evaluation was performed. The analysis was conducted by dividing civil engineering facilities by type, construction nature, construction cost, contract nature, and delivery method. Planned and actual construction cost and period were compared during the planning, design, and construction process of civil engineering facilities. There is a possibility of input errors in project performance data, this paper proposes to the post-evaluation center should perform post-evaluation. Also, post-evaluation implementation guidelines for change orders should be revised. Additionally, further analysis of each facility was proposed through continuous data collection.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.19 no.5
• /
• pp.941-950
• /
• 2024

This study employed network analysis techniques to examine the relationships between spatiotemporal factors associated with crimes in public restrooms, drawing on diverse relevant data sources. We then evaluated the relative importance of these factors in crime occurrence. Variables related to crime incidence were identified, and their interconnectedness was assessed for network analysis, resulting in a data-driven network model with complex relational structures. The network model contributed to calculating the weight of each factor and identifying key elements. The location of public restrooms, usage time, surrounding environment, and facility conditions emerged as crucial factors in crime occurrence, with lighting quality and local security status showing high weightings. These findings can be utilized to prioritize interventions in public restroom design and management to enhance safety. The network analysis methodology demonstrated its potential in proposing crime prevention measures for public spaces, including restrooms, and contributing to the creation of safer public environments.

• Nuclear Engineering and Technology
• /
• v.55 no.6
• /
• pp.2335-2347
• /
• 2023

As medical facilities are usually built at urban areas, special concrete aggregates and evaluation methods are needed to optimize the design of concrete walls by balancing density, thickness, material composition, cost, and other factors. Carbon treatment rooms require a high radiation shielding requirement, as the neutron yield from carbon therapy is much higher than the neutron yield of protons. In this case study, the maximum carbon energy is 430 MeV/u and the maximum current is 0.27 nA from a hybrid particle therapy system. Hospital or facility construction should consider this requirement to design a special heavy concrete. In this work, magnetite is adopted as the major aggregate. Density is determined mainly by the major aggregate content of magnetite, and a heavy concrete test block was constructed for structural tests. The compressive strength is 35.7 MPa. The density ranges from 3.65 g/cm³ to 4.14 g/cm³, and the iron mass content ranges from 53.78% to 60.38% from the 12 cored sample measurements. It was found that there is a linear relationship between density and iron content, and mixing impurities should be the major reason leading to the nonuniform element and density distribution. The effect of this nonuniformity on radiation shielding properties for a carbon treatment room is investigated by three groups of Monte Carlo simulations. Higher density dominates to reduce shielding thickness. However, a higher content of high-Z elements will weaken the shielding strength, especially at a lower dose rate threshold and vice versa. The weakened side effect of a high iron content on the shielding property is obvious at 2.5 µSv=h. Therefore, we should not blindly pursue high Z content in engineering. If the thickness is constrained to 2 m, then the density can be reduced to 3.3 g/cm³, which will save cost by reducing the magnetite composition with 50.44% iron content. If a higher density of 3.9 g/cm³ with 57.65% iron content is selected for construction, then the thickness of the wall can be reduced to 174.2 cm, which will save space for equipment installation.

• Journal of the Society of Disaster Information
• /
• v.17 no.4
• /
• pp.684-693
• /
• 2021

Purpose: The purpose is to establish a safe facility environment from abnormal voltages such as lightning by developing a smart land resistance measuring device that can acquire real-time land resistance data using Arduino. Method: This paper studied design models and application cases by developing a land resistance acquisition and analysis system with Arduino and a power line communication (PLC) system. Some sites in the wind power generation complex in Gyeongsangnam-do were selected as test beds, and real-time land resistance data applied with new technologies were obtained. The electrode arrangement adopted a smart electrode arrangement using a combination of a Wenner four electrode arrangement and a Schlumberger electrode arrangement. Result: First, the characteristic of this technology is that the depth of smart multi-electrodes is organized differently to reduce the error range of the acquired data even in the stratigraphic structure with specificity between floors. Second, IT convergence technology was applied to enable real-time transmission and reception of information on land resistance data acquired from smart ground electrodes through the Internet of Things. Finally, it is possible to establish a regular management system and analyze big data accumulated in the server to check the trend of changes in various elements, and to model the optimal ground algorithm and ground system design for the IT convergence environment. Conclusion: This technology will reduce surge damage caused by lightning on urban infrastructure underlying the 4th industrial era and design an optimized ground system model to protect the safety and life of users. It is also expected to secure intellectual property rights of pure domestic technology to create jobs and revitalize our industry, which has been stagnant as a pandemic in the post-COVID-19 era.

• Journal of Korean Society of Transportation
• /
• v.34 no.3
• /
• pp.207-221
• /
• 2016

In Korea, older pedestrian accounted for 57% of all pedestrian deaths although a ratio of older pedestrian accidents to total pedestrian accidents was only 25.9%. Though ageing population problem becomes more challenging for road safety, little is know about the behaviour of older pedestrian's behaviour. This study aimed to identify road crossing behaviour of older pedestrian at three-lane unsignalized crosswalks using video image analysis and to compare the behaviour of older pedestrian to younger one by indicators including approaching speed, the number of walking steps and other factors. The results showed that there was a difference of approaching time at kerb, waiting time at kerb, the number of glances at kerb, and the number of glances at crossing between two groups under the situation of car approaching to crosswalks. It also showed that older pedestrian usually spent 1.16 times more than younger pedestrian to walk across the crosswalk with only 84.4% of walking speed of younger pedestrian. The number of steps of older pedestrian for road crossing was 1.12 times higher with 90% shorter steps than younger pedestrian. It was concluded that older pedestrian usually decided to walk across in case of 1.67 times longer headway than younger pedestrian's decision. These results could be applied in road and facility design for better safety of older pedestrians.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.19 no.2
• /
• pp.50-55
• /
• 2018

Earthquakes are almost impossible to predict and take place in a short time. In addition, there is little time to take aggressive action when an earthquake occurs. Therefore, there are more casualties and property damage than with other natural disasters. Recently, earthquakes have been occurring all over the world. As the number of earthquakes increase, studies on the safety of structures are being carried out. On the other hand, there are few studies on the electric facilities, which are relatively non - structural factors. Currently, electrical equipment in Korea is often not designed for earthquake safety and is quite vulnerable to damage when an earthquake occurs. Therefore, in this study, modeling was conducted through ABAQUS similar to an actual cabinet panel and 3D dynamic nonlinear analysis was performed using a natural seismic. According to seismic zone I and normal ground rock conditions of the power transmission and transmission facility seismic design practical guide, the maximum response acceleration of the performance level was 0.157g. In this study, however, it was not safe to reach the limit state of 30% of the analytical result at 0.1g for the general cabinet panel. From the results, the seismic fragility curve was derived and analyzed. The derived seismic fragility curve is presented as a quantitative basis for determining the limit state of the cabinet panel and can be utilized as basic data in related research.

• Journal of the Korean Geotechnical Society
• /
• v.33 no.10
• /
• pp.25-31
• /
• 2017

The buffer is one of the major components of an engineered barrier system (EBS) for the disposal of high-level radioactive waste (HLW). As the buffer is located between a disposal canister and host rock, it is indispensable to assure the disposal safety of high-level radioactive waste. It can restrain the release of radionuclide and protect the canister from the inflow of groundwater. Since high quantity of heat from a disposal canister is released to the surrounding buffer, thermal properties of the buffer are very important parameters for the analysis of the entire disposal safety. Especially, temperature criteria of the compacted bentonite buffer can affect the design of HLW repository facility. Therefore, this paper investigated thermal properties for the Kyungju compacted bentonite buffer which is the only bentonite produced in South Korea. Hot wire method and dual probe method were used to measure thermal conductivity and specific heat capacity of the compacted bentonite buffer according to the temperature variation. Thermal conductivity and specific heat capacity were decreased dramatically when temperature variation was between $22^{\circ}C{\sim}110^{\circ}C$ as degree of saturation decreased according to the temperature variation. However, there was little variation under the high temperature condition at $110^{\circ}C{\sim}150^{\circ}C$.