• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.10
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• pp.1-8
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• 2016

Automation of inventory management in a steel plate factory was a difficult problem unresolved for a long time. And now, it is also necessary to work diligently in the steel industry on efficient inventory management of thick plates. So far, the environmental characteristics of stacked thick plates means it is not easy to apply advanced technology for their automatic identification. In this paper, we propose a thick-plate robotic scanning system based on radio-frequency identification (RFID) that can provide quick and accurate inventory management by acquiring plate information after the scanning automatically recognizes the RFID tags under difficult load conditions. This system is equipped with a crane to move the plates in a pulled-up operation. It is equipped with a plate-only linear dipole antenna only for scanning the position of the plate tag. Only the linear dipole antenna, while moving the x-axis and y-axis information, automatically identifies the tag information attached to the plate. The tag information acquired by the system is used for stockpiling and is managed by steel plate inventory control software. The effectiveness of the proposed system is verified through field performance evaluation. As a result, the recognition rate of the plate tags is 99.9% at a maximum distance of 320 cm. The developed thick-plate antenna showed excellent performance compared to an existing commercial antenna.

• Korean Journal of Construction Engineering and Management
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• v.21 no.5
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• pp.3-10
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• 2020

Subcontracting of construction is essential to carry out public construction projects. Subcontractor of the construction work shall enter into a contract with the original contractor without directly entering into a contract with the owner. Subcontracts are therefore greatly affected by the original contract with the owner. To protect subcontractors, the Fair Trade Act is enacted and the construction company's standard subcontracting contract is in operation. However, subcontracts are not properly reflected in the Government contract system, which deals with the relationships between the owner and the original contractor. In particular, the subcontractor may complain of difficulties at the public construction site as such procedures are not properly reflected in the construction work standard subcontract, although various procedures shall be carried out depending on the amount when change order occurs in subcontracts. Thus, the direction of improvement of subcontracting systems was proposed in the case of change order at public construction project sites as follows: First, the rights of subcontractors should be strengthened. Second, in order to resolve the information non-identity, subcontractors should have access to information related to subcontracts. Third, the status of subcontractor shall be guaranteed by reflecting the characteristics of the subcontract when the original contract for public works is concluded. Fourth, the dispute settlement method should be prioritized over litigation in order to fair subcontracting.

• Journal of Ocean Engineering and Technology
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• v.30 no.4
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• pp.334-340
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• 2016

The combustion chamber of a diesel engine is often exposed to a more serious wear and corrosion environment than other parts of the engine because its temperature increases as a result of using heavy oil of low quality. Therefore, repair and built-up welding methods must be performed on worn or corroded parts of the piston crown, exhaust valve, etc. from an economical point of view. In this study, Inconel 718 filler metal was used in repair welding on the groove of a forged steel specimen for a piston crown, along with built-up welding on the surface of another forged steel specimen. Then, the corrosion characteristics of the weld metal zone for the repair welding and the deposited metal zone for the built-up welding were investigated using electrochemical methods in a 35% H₂SO₄ solution. The deposited metal zone indicated better corrosion resistance than the weld metal zone, showing a nobler corrosion potential, higher impedance, and smaller corrosion current density. It is considered that metal elements with good corrosion resistance were generally included in the filler metal, and these elements were also greatly involved in the deposited meta by built-up welding, whereas the weld metal consisted of metal elements mixed with both the filler metal and base metal elements because of the molten pool produced by the repair welding. Finally, it is considered that the hardness of the weld metal was increased by the repair welding, whereas the built-up welding improved the corrosion resistance of the deposited metal.

• The Journal of Korean Philosophical History
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• no.31
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• pp.321-346
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• 2011

This is a preliminary study in order to deal intensively with the overall characteristics of Korean military science in the future days. First off, the history of military science of China based on the precedent studies was recapitulated, and a comparative study on the acceptance process of the books on military art and science, as well as on understanding patterns of literati on the subject through literature searches, ranging from the Three Kingdoms Period to the Goryeo Dynasty in Korean peninsula, was conducted. In case of Korea, the Chinese books on military strategy, including Sun Tzu's the Art of War, had already been passed down during the Three Kingdoms Period, and broadly read by scholarly people. They had utilized diverse methods based on their knowledge of Confucianism. In the reference materials, the authors of Korean military strategy books had greatly relied upon the Chinese books on military strategies, however, they had made the military principles run in their own way. At the end of Goryeo Dynasty, 'Military Science' had been well established as a subject in academia, and this curriculum had been taught not only at the National Confucian Academy, Seonggyun-gwan, in the capital but also at the country public school ("Hyanggyo") in the province together with Confucianism. Because of the limits of reference materials, however, it was difficult to confirm whether or not such strategic experiences were actually led to the publication of the books on military art and science, or how many books on military strategies and tactics had been published up until the end of Goryeo Dynasty. But, the facts that there were not many publications of the books on military strategies during the era of Three Kingdoms and of Goryeo Dynasty don't mean that Korean military science had entirely relied upon the Chinese military art and science. For instance, such strategies, tactics and leaderships as exhibited in the process of the Great Victory at Salsu River ("Salsu Daecheop") achieved by General Eulji Mun-deok, as well as the Great Victory at Gwiju ("Gwiju Daecheop") achieved by General Kang Gam-chan could never happen by chance.

• Review of Culture and Economy
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• v.19 no.2
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• pp.97-120
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• 2016

This study aims to identify how performing artists in Korea, who are the target beneficiaries of the Arts Council Korea's Performing Arts Fostering Program, Chang-jak-san-shil(CJSS), would perceive and assess the current state of CJSS and its effects. To do so, this paper has adopted a bottom-up approach as a theoretical lens for policy evaluative analysis. This research engages with qualitative research design by conducting a series of in-depth interviews and FGIs with 28 participants in total. The interview participants consist of CJSS grantees(n=21) and peer-review panels(n=7) based on the intension to enhance objectivity and reliability of the study. Results of the data analysis suggest that the grant program still carries pressing needs to achieve a success as follows: providing post-program support, enhancing transparency of the panel appointment process and the peer review process, reflecting different nature of each arts discipline, and having more open communications with arts professionals. Based on these findings, this paper will provide and discuss about policy implications which can contribute to the performing arts domain at large.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.10
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• pp.117-124
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• 2019

Military Vehicles of the Korean army had been developed before 2004 and used manual transmissions. Manual transmissions contain a clutch system regulating the force from engine to transmission. In this study, a 2.5-ton military vehicle's clutch system was investigated. The existing clutch system had the characteristics that need to adjust the clearance between the clutch cover and release bearing. Improper clearance led to early wear of the clutch disk and failure of the clutch cover. To solve these problems, an improved clutch system was suggested and tested. The improved clutch system contains auto adjustment of the clearance and an enhanced clutch disk. To verify the improved clutch systems, 2 stage tests were conducted: an accelerated life test of the clutch system, and a driving test by trainee of driving more than 3,000km. As a result, the problems caused by the improper clearance adjustment were solved and this design was verified.

• The Journal of the Convergence on Culture Technology
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• v.5 no.4
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• pp.277-282
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• 2019

This study analyzed the determinants of the financial Soundness of savings banks. In particular, empirical analysis was carried out on how the loan deposit ratio correlates with financial soundness after restructuring. As the restructuring of savings banks was finalized in 2014, asset management changed and it is time to analyze the financial characteristics of savings banks. In summary, the relationship between the savings bank lending rate and the NPL ratio is estimated to have a negative value at the 1% significance level. In other words, the higher the mortgage rate, the lower the substandard and below ratio. It can be said that it is not easy for a savings bank to build an aggressive loan portfolio. In other words, the more difficult it is to finance loans through savings deposits, the more likely the risk aversion tends to be. The higher the corporate loan ratio, average interest expense, and economic growth rate, the higher the risk index. The larger the asset size and the higher the loan growth rate, the lower the risk index. Increasing the mortgage rate may reduce risk-seeking behavior, but it does not mean that it is unconditionally positive for savings banks. Therefore, the loan deposit rate regulation should reduce the incentives for excessive asset expansion and manage preemptive soundness through lending portfolio management.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.10
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• pp.738-746
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• 2019

Instead of hydraulic actuation systems, an electromechanical actuation system is more efficient in terms of weight, cost, and test evaluation in the thrust vector control of the 7-ton gimbal engine used in the Korea Space Launch Vehicle-II(KSLV-II) $3^{rd}$ stage. The electromechanical actuator is a kind of servo actuator with position feedback and uses a BLDC motor that can operate at high vacuum. In the case of the gimballed rocket engine, a synthetic resonance phenomenon may occur due to a combination of a vibration mode of the actuator itself, a bending mode of the launcher structure, and an inertial load of the gimbals engine. When the synthetic resonance occurs, the control of the rocket attitude becomes unstable. Therefore, the requirements for the stiffness have been applied in consideration of the gimbal engine characteristics, the support structure, and the actuating system. For the 7-ton gimbal engine of the KSLV-II $3^{rd}$ stage, the stiffness requirement of the actuation system is $3.94{\times}10^7N/m$, and the direct drive type electromechanical actuator is designed to satisfy this requirement. In this paper, an equivalent stiffness analysis model of a direct drive electromechanical actuator designed based on the stiffness requirements is proposed and verified by experimental results.

• Journal of the Korea Society of Computer and Information
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• v.26 no.10
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• pp.83-91
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• 2021

In this paper, presents an efficient education method for training specialized edutainment SW education instructors and drone realistic media creators, not just training to acquire certificates through drone manipulation training. To this end, the NCS-based curriculum was derived. The developed curriculum includes the edutainment drone curriculum and the realistic media creator curriculum. Among them, core responsibilities were defined for the drone control curriculum and core tasks, knowledge, and attitudes were described for each. After that, a detailed curriculum for drone control was derived. In the realistic media creator curriculum, pilot education was conducted to actually produce advertisement videos to foster experts who can work directly in the industrial field. Finally, through holding an online conference in a metaverse environment, a virtual conference was operated to share and discuss media videos produced by trainees. After the end of education, the efficiency of this curriculum was proved through education satisfaction analysis for 46 education graduates. This paper presented a method to achieve internalization of SW education in non-face-to-face online education that our society must solve after post-COVID-19. In addition, an efficient educational method in a realistic media environment was suggested by showing a realistic media creator training curriculum, pilot programs, and metaverse conference management cases.

• Journal of the Korean Geotechnical Society
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• v.34 no.11
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• pp.81-92
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• 2018

For a marine bridge foundation construction, a large-circular-steel-pipe has been proposed for supporting vertical load and preventing water infiltration. However, a ship collision can adversely affect the structural stability. This paper presents a fundamental study on dynamic responses of the large-circular-steel-pipe by an impact load. In laboratory experiments, small-scaled steel pipe is installed in a soil tank. The soil height and water level are set to 23 cm and 25~70 cm, respectively. The upper part of the steel pipe is impacted using a hammer to simulate the ship collision. The dynamic responses are measured using accelerometers and strain gauges. Experimental results show that the strain decreases as the measured location is lowered. The higher frequency components appear in the impact load condition compared to the microtremor condition. However, the higher frequency components measured at the strain gauge located below the water level do not appear. For the accelerometer signal, the maximum frequency under the impact load is higher than that of the microtremor. The maximum frequency decreases as water level increases but it is larger than the maximum frequency of the microtremor. This study shows that strain gauge and accelerometer can be useful for evaluating the dynamic responses of large-circular-steel-pipes.