• 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.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.21 no.5
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• pp.42-56
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• 2022

The thesis is automated traffic control equipment system aims to improve. Areas where improvement is needed about the existing automated traffic control equipment by applying the latest technology and to improve the things that can be derived. Reflecting the derived improvements, we intend to present a plan for the design and implementation of a new unmanned traffic control device. The main improvements were designed to change the housing material of the unmanned traffic control equipment, simplify the configuration of the equipment, reduce the weight of the equipment, and change the purpose of the software. In order to evaluate the objective performance of the improved unmanned traffic control equipment through this study, it was requested to a public certification authority. The reliability of the equipment was secured through KC certification and durability test. It is intended to present the feasibility of securing the marketability of the unmanned traffic control equipment by comparing and evaluating the construction period and installation cost with the existing unmanned traffic control equipment.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.4
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• pp.723-730
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• 2023

Due to the recent development of battery technology, various types of means of transportation such as electric kickboards, Segways, and electric bicycles have emerged, which can be defined as Personal Mobility. In this paper, as the incidence of safety accidents increases due to the increase in the number of users of Personal Mobility, safety helmet devices that strengthen safety capabilities and peripheral recognition functions were studied. In order for the helmet to send a safety signal, Arduino was used as a base to set the value of the sensor according to changes in distance and angle using the ultrasonic sensor to minimize errors and ensure smooth recognition. In addition, a gyro sensor was used to turn on the direction indicator according to each slope. Using a CDS sensor, the LED is designed to turn on when it goes below 150 lux at night. Finally, it is possible to check whether a helmet is worn within 5cm, and when driving at an average speed, the direction indicator light is turned on at 10 degrees, and the LED is turned on at less than 150 lux.

• Asia Marketing Journal
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• v.14 no.3
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• pp.119-135
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• 2012

The purpose of this research is to investigate the effects of the product display type on the consumers' purchase intention, attitude toward store, and revisit intention in the various mobile shopping situations. To test the hypothesis, between-subjects experiment with 3 mobile shopping situations (outdoor place, public transportation, commercial facilities) by 3 product display types (search, category, product) was conducted, and analyzed with ANCOVA (analysis of covariance). The result of the experiment shows there are no main effects of the mobile shopping situations and the product display types, but the interaction effects of the product display type and the mobile shopping situation on the purchase intention and the revisit intention are statistically significant. However the attitude toward the store is not affected by the treatments. Experiment results suggest that the positive consumer responses in terms of the purchase and revisit intention can be achieved when the product display is matched with the situation in the mobile shopping setting. Controlling consumers' evaluation on the product information and their experience of online shopping, we can take these effect as the results of match-up between the product display type and the situational factors surrounding mobile shopping. The result provides strong support for the location-based service in mobile shopping. Most of the mobile device can utilize the consumers' location which can be easily interpreted as the situational factors. With regard of the level of the external stimulation, the shopping service providers can offer the main interface with the right match with the consumers' situations. When the external stimulation level is high, they should provide the category display or product display in the target promotion in their mobile shopping apps. However if the target is on the way with the low external stimulation level, they should provide the search format as the main interface in their apps. More interestingly, this kind of manipulation does not affect the consumers' attitude toward the store according to our research result. Future research direction is discussed.

• Transactions of the Korean hydrogen and new energy society
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• v.34 no.6
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• pp.581-586
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• 2023

As the development of alternative energy is required due to the depletion of fossil fuels, interest in the use of hydrogen energy is increasing. Hydrogen is a promising clean energy source with high energy density and can lead to the application of environmentally friendly technologies. However, due to difficulties in production, storage, and transportation that prevent the application of hydrogen-based eco-friendly technology, research on reforming reactions using dimethyl ether (DME) is being conducted. Unlike other hydrocarbons, DME is attracting attention as a hydrogen carrier because it has excellent storage stability and transportability, and there is no C-C bond in the molecule. The reaction between DME and steam is one of the reforming processes with the highest hydrogen yield in theory at a temperature lower than that of other hydrocarbons. In this study, a hydrogen reforming device using DME was developed and a catalyst prepared by supporting Cu in alumina was put into a reactor to find optimal hydrogen production conditions for supplying hydrogen to fuel cells while changing reaction temperature (300-500℃), pressure (5-10 bar), and steam/carbon ratio (3:1 to 5:1).

• Korean Chemical Engineering Research
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• v.61 no.4
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• pp.611-618
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• 2023

The purpose of the refueling protocol and the contents of SAE J2601, which is used as the basis for hydrogen vehicles refueling around the world, were investigated, and research contents related to domestic protocols were also investigated. In addition, the components of the hydrogen refueling performance evaluation device developed in Korea and the method for evaluating the performance and safety of hydrogen refueling stations were reviewed. And, the result were analyzed by applying it to the hydrogen refueling stations currently operating in Korea. In addition, an economic feasibility analysis was conducted using data collected from domestic hydrogen refueling stations. In order to secure the safety and economy of a hydrogen refueling station, the protocol must be satisfied, and in order to satisfy the protocol, it is necessary to evaluate whether the refueling temperature, refueling pressure, and refueling flow are controlled within a safe range.

• Journal of the Korean Society of Radiology
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• v.17 no.7
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• pp.1179-1187
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• 2023

Recent advancements in modern transportation have led to the active development of various biomedical signal and medical imaging technologies. Particularly, in the field of cognitive/neuroscience, the importance of electroencephalography (EEG) measurement and the development of accurate EEG measurement technology in moving vehicles represent a challenging area. This study aims to extensively investigate and analyze the trends in technology research utilizing EEG during driving. For this purpose, the Scopus database was used to explore EEG-related research conducted since the year 2000, resulting in the selection of about 40 papers. This paper sheds light on the current trends and future directions in signal processing technology, EEG measurement device development, and in-vehicle driver state monitoring technology. Additionally, a ultra compact 32-channel EEG measurement module was designed. By implementing it simply and measuring and analyzing EEG signals, in-vehicle EEG module's functionality was checked. This research anticipates that the technology for measuring and analyzing biometric signals during driving will contribute to driver care and health monitoring in the era of autonomous vehicles.

• Design & Manufacturing
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• v.18 no.2
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• pp.1-8
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• 2024

Unlike the roll-to-roll process that uses a steel roll and a nip roll, a vacuum roll can hold and transfer a thin film using a single roll. To precisely manufacture a vacuum roll, a thin outer cylinder must be machined, which is assembled on the outside of the roll and contacts the film via vacuum pressure. In this study, the effects of jaw width and chucking force on the deformation of the outer cylinder during the turning process were investigated using analysis, and a precision machining and burr removal process was developed. The deformation of the outer cylinder decreased almost linearly with increasing jaw width and increased with higher chucking force and larger cylinder diameter. Additionally, the deflection due to the weight of the outer cylinder was approximately three times greater than that caused by film tension. For the machined outer cylinder, a burr removal experiment was conducted, and concentricity and cylindricity were measured. Using a device that removes burrs by rotating a wheel connected to the main shaft at high speed, it was found that burrs generated on the inner diameter could be removed very efficiently. On the vacuum side, the concentricity errors of the inner and outer diameters were 0.015 mm and 0.014 mm, respectively, and on the opposite side, they were 0.006 mm and 0.010 mm, respectively. Additionally, the measurement of Total Indicator Runout (TIR) according to the angle showed that the maximum cylindricity of the outer and inner diameters was 0.02 mm and 0.025 mm, respectively. Finally, through burr-height measurement at the hole boundary, it was found that the heights were within 0.05 mm.

• The Korean Journal of Air & Space Law and Policy
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• v.28 no.1
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• pp.55-71
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• 2013

By aircraft from Aviation regulations and institutional regulatory framework for ensuring the safety is secured. State-of-the-art aircraft, according to the type of development and diversification, modernization and new types of aircraft are operated. In particular, light aircraft and ultralight flying device such as the gyro-plane and unmanned flying devices is introduced a new device, and the device operates at these flight in accordance with the standards of the Aviation Act regulations may not occur often. Variety of light aircraft and ultra-light aircraft assembly, can be adapted for a person engaged in the business of aviation safety management and to perform the legal basis was established. Depending on the classification of newly introduced aircraft, the biggest change is the introduction of the concept of the LSA. In Korea, the various light aircraft are operating, but these aircraft range not clearly Aviation Regulations had difficulty in ensuring safety. This study examined the differences between international rules and regulations of Korea about the classification of aircraft. The LSA are included in aircraft categories internationally, but LSA will not be included in the aircraft categories, which is one of a range of powered flight device exists in Korea Aviation Act. Limit for maximum continuous power speed in a LSA, it is a limit on the right of the people who want using the high-performance plane. Also it is an international trend does not fit in, and is consistent with the intent of LSA manufacturer. Delete the content from a range of future aviation law revisions and light aircraft-related provisions to limit the maximum continuous power speed is considered to be suitable for the purpose of introducing the light aircraft industry. The laws and regulations set up in order to ensure the safety of ultralight aircraft categories existing in ultralight aircraft that exceeds the purpose of the introduction of LSA technology development at home and abroad, and is intended to reflect. These standards complement of aircraft operation is not appropriate for the situation unless the country is difficult to ensure the safety of operations. Also developed in other countries, the introduction of aircraft operating in the country, so many problems occur early revision is required.

• Journal of Korean Society of Transportation
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• v.22 no.7 s.78
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• pp.119-129
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• 2004

This paper is designed to report the results of development and validation procedures in relation to the Freeway Incident Management System (FIMS) prototype development as part of Intelligent Transportation Systems Research and Development program. The central core of the FIMS is an integration of the component parts and the modular, but the integrated system for freeway management. The whole approach has been component-orientated, with a secondary emphasis being placed on the traffic characteristics at the sites. The first action taken during the development process was the selection of the required data for each components within the existing infrastructure of Korean freeway system. After through review and analysis of vehicle detection data, the pilot site led to the utilization of different technologies in relation to the specific needs and character of the implementation. This meant that the existing system was tested in a different configuration at different sections of freeway, thereby increasing the validity and scope of the overall findings. The incident detection module has been performed according to predefined system validation specifications. The system validation specifications have identified two component data collection and analysis patterns which were outlined in the validation specifications; the on-line and off-line testing procedural frameworks. The off-line testing was achieved using asynchronous analysis, commonly in conjunction with simulation of device input data to take full advantage of the opportunity to test and calibrate the incident detection algorithms focused on APID, DES, DELOS and McMaster. The simulation was done with the use of synchronous analysis, thereby providing a means for testing the incident detection module.