• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.11
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• pp.574-582
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• 2018

In systems such as railways, automobiles, and airplanes, system malfunctions may lead to accidents, which often cause serious personal injury and economic loss. In previous studies, failure analysis has been performed, and safety measures derived using the component level information to reduce damage when a failure occurs. However, in functional safety concept, a focus is placed on lowering the frequency of occurrence of failures by performing risks analysis, setting up safety goals, and designing safety functions. Therefore, it is necessary to study how to determine the required safety function that can reduce the failure frequency to the acceptable level. To achieve this, we first studied a failure modeling method using SysML. It was then presented how several alternatives can be assessed to determine the desired safety function by simulating the generated SysML failure models and calculating the ability to reduce the failure frequency. A case study of a railway signaling system was done, demonstrating the effectiveness of the approach. We assessed whether the safety objectives were met for the alternative design of the railway signaling system through M & S. The results can be useful in that it can be applied from the early design phase and allow to choose the appropriate safety function that satisfies safety objectives among various design alternatives.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.9
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• pp.541-550
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• 2019

An emergency generator is key equipment for fire-fighting to supply power to fire-fighting facilities, which protect property and people in cases of fire accidents. A rated load test for emergency generators must be carried out by connecting an emergency load to the generator in accordance with related regulations. However, a no-load test has been performed for emergency generators in general since serious problems can occur when the main power is cut off, including the damage of customer devices and shut down of critical loads. Therefore, this paper proposes a load test method for an emergency generator using energy storage system (ESS) without the interruption of main power. The emergency power system was also modeled based on PSCAD/EMTDC software, and a 200-kW scale ESS load test device was implemented. The simulation and test results show that the load test method is useful and practical for an emergency power supply system.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.12
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• pp.178-185
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• 2018

A self-report evaluation is used to prevent driving accidents by elderly drivers. The majority of normal older adults may have mild cognitive impairment with reduced cognitive function. These depressed cognitive functions may be variables that affect the performance of elderly drivers. This study confirmed the cognitive functions that affect the self-reported evaluation for elderly drivers with mild cognitive impairment. Based on the results of the Korean Version of the Montreal Cognitive Assessment, 103 elderly drivers were classified into mild cognitive impairment and normal groups of elderly drivers. The Korean-Drivers 65 plus scores used in the self-reported evaluation of the two groups were compared, and the cognitive functions affecting the evaluation were analyzed. Results found the mild cognitive impairment group showed a significantly lower evaluation performance compared to the normal group, and the self-reported evaluation results of the elderly driver with mild cognitive impairment showed a significant correlation between visuoconstructional skills and delayed recall. As a result of regression analysis, the visuoconstructional skill was identified as the cognitive function with the strongest influence on the self-reported evaluation performance. Delayed recall was also found to have a partial effect but not at the level of altering the self-reported evaluation results of the elderly driver with mild cognitive impairment.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.3
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• pp.611-619
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• 2021

Porous asphalt pavement (PAP) has many functions, such as reducing accidents and decreasing noise. On the other hand, vulnerability is inevitable because PAP contains approximately 20% porosity. This study evaluated the effects of the maximum aggregate size (MAS), temperature, and porosity on the PAP durability. The indirect tensile strength measures durability. This study tested the samples that stayed dry and were moisturized by freezing and thawing for mixtures having the same porosity of 20% and MAS of 13mm, 10mm, and 8mm. The same test was performed on a mixture of 20% and 22% voids made of the same material with a MAS of 10mm. As a result, for 20% porosity, significant differences in the changes in MAS and temperature were found. A clear difference was observed between 8mm and 13mm under dry conditions, but there were no other significant differences in the MAS change. Furthermore, there was a clear difference in temperature for the change in porosity and temperature, but the gap in 2% porosity at 20% did not show a clear difference. Therefore, it is necessary to develop a more durable PAP through quantitative evaluations of the factors affecting the PAP durability.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.2
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• pp.179-187
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• 2021

In the past five years, form construction, which accounts for approximately 25% of the total construction period, has continued to occur without a significant decrease in the number of deaths, with the largest proportion of collapse accidents. Accordingly, this study analyzed the difference in perception between the manager and worker by a questionnaire survey on the degree of risk and safety management level regarding a mold collapse accident. The survey was conducted in three groups: safety manager, field worker, and field manager. The results of the survey were analyzed by an independent sample T-Test using the SPSS program. As a result, there was almost no difference in recognition between managers, but a significant difference in recognition between managers and workers. In addition, there was a difference in management perception between the administrator and worker, which clearly shows the difference in the position between the administrator who manages and supervises hazardous disaster factors and the worker who works directly in the field. Such differences in perception can be a factor that cannot be mitigated. Based on this study, more developed research can narrow the perception gap between managers and workers and be used as a basic material for disaster research.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.12
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• pp.227-233
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• 2020

The demand for porous asphalt mixtures is increasing because it has a range of functions, such as reducing traffic accidents and traffic noise. On the other hand, its application is delayed due to concerns about durability. This study examined the effects of the maximum aggregate size, temperature, and porosity of an asphalt mixture on the durability. To this end, the durability measure was set to the Cantabro loss rate. Mixtures having the same porosity of 20% and the maximum aggregate diameters of 13 mm, 10 mm, and 8 mm were tested at 20℃ and -20℃. Mixtures containing 20% and 22% voids with the same material having the same diameter were tested. With 20% porosity, there was no significant difference in durability when there was a change in the maximum aggregate size. There was a significant difference between 20℃ and -20℃, but no significant difference in durability when there was a 2% difference between 20% and 22%. The significance of this study is that the durability was presented quantitatively by tests and statistical analysis. This research will help improve the durability of porous asphalt mixtures by evaluating the factors affecting the durability quantitatively.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.4
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• pp.67-74
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• 2021

Domestically, technical condition evaluation for breakwaters has been conducted through safety checks and safety diagnosis. If necessary, maintenance for the facility is conducted. However, in recent years, the need for infrastructure management has been increasing from a life-cycle-cost perspective. For these reasons, the "Sustainable Infrastructure Management Basic Act" was enacted. Previously, only the technical part of the breakwaters was evaluated. However, based on the act, comprehensive management of breakwaters will be possible through performance improvement by adding economic and political evaluations. In this study, evaluation factors and evaluation methods were developed for a breakwater rehabilitation project. The purpose of this study is to present a development direction, items, and methods for the evaluation of breakwater performance improvement to be applied in future practice. This study reviews the concept of maintenance and performance improvement, the literature related to performance improvement, and the project type for the common standard of performance improvement. Evaluation items and evaluation methods for breakwater rehabilitation are suggested to be reviewed by experts. The methodology suggested in this study could be used for preventive maintenance and to reduce accidents.

• Journal of Internet Computing and Services
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• v.23 no.1
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• pp.135-145
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• 2022

This paper presented a method to build a predictable smart ammunition logistics system using the 4th industrial technology for ammunition logistics, which is the core functions in the field of defense and logistics. We have analyzed the current level of ammunition logistics with various perspectives such as domestic and overseas logistics policies, technology trends, ammunition logistics characteristics, the smart logistics certification measures by Ministry of Land, Infrastructure and Transport. As a result it is considered that the current ammunition logistics needs needs improvement. To improve this, we presented a direction based on the implications derived after analyzing various ongoing programs such as wired/wireless-based automation, smart ammunition depots, and logistics innovation of the army, navy, and air force that can be applied to the ammunition logistics. In order to implement a data-based smart ammunition logistics management system that can achieve innovation and efficiency of total life cycle while meeting changes in the battlefield environment, we presented 4 objectives such as "automation and modernization of field work", "3D-based storage management & improvement of issuing at war," and "data management for prediction-oriented ammunition management". it is expected that there will be benefits such as improvement of operational continuity, guarantee of ammunition reliability, budget reduction, improvement of inefficiencies such as delay, waiting, and double work, and reduction of accidents.

• Journal of the Society of Disaster Information
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• v.19 no.1
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• pp.1-9
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• 2023

In order to carry out construction work, it is urgent to introduce a proper wage system so that the cost burden of projects that have been won due to bleeding competition among original government buildings based on low-priced bids can be transferred to subcontractors. Purpose: Construction with illegal multi-level industrial structure needs to improve the wage reduction environment leading to order (100%) → original contractor (80%) → subcontractor (65%) → load contractor (65%) and aims to ensure wages for end workers. Method: Investigate the current status of labor cost appropriate payment plan in the construction industry, and investigate the case of the appropriate wage system (P.W) in the United States. In addition, the effect and direction of the appropriate wage system are presented. Result: Individual minimum wage security was also mentioned in the Constitution, and many researchers suggested that only the introduction of an appropriate wage system could solve the problem of reducing worker labor and ensure quality and safety. Conclusion: The proper wage system in the construction industry will block illegal multi-level and illegal foreign work, improve the labor environment in the construction market, create an influx of young workers, and have a significant impact on the construction industry's competitive structure, safety, and quality.

• Journal of Industrial Convergence
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• v.21 no.6
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• pp.43-51
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• 2023

This study analyzed the patent status of the outdoor exercise equipment used primarily by the elderly. The purpose is to utilize the basic data obtained to promote the health of the elderly. The information on the patent was collected from KIPRIS, an information search service provided by the Korean Intellectual Property Office. The search term used was 'outdoor exercise equipment', directly related patents were selected, and a final 157 were analyzed. As a result of the analysis, first, patent registration began in 2007, and 2-3 patents were registered on average every year. Second, patents from the perspective of sports convergence that provide an exercise prescription system using wireless communication, such as the ability to generate electricity by operating a power generation module, providing information on the user's exercise amount, or preventing the loss and theft of weights and safety accidents due to their characteristics, were searched for. Lastly, patents related to exercise equipment that can provide user convenience and increase the frequency of use of exercise equipment were searched. The results of this study confirmed that outdoor exercise equipment is being developed more for the elderly and their convenience, and that companies and public institutions are showing increased interest in outdoor exercise equipment for the elderly. In addition to patent trends analysis, follow-up research in connection with exercise programs using outdoor exercise equipment is needed to develop practical and convenient outdoor exercise equipment in the future.