• Journal of the Korean Society of Safety
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• v.22 no.6
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• pp.41-45
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• 2007

Short circuit and ground fault account for the primary causes of electrical fires. In this research, real-scale experiments were conducted to assess the possibility of electrical fires due to these causes. The experiment conditions were identical with an actual fire accident, in which the power cable was supported by an iron fence. The purposes of this research are to investigate the short circuit caused by wire cutting, the conductivity of the iron fence depending on its coating conditions, and the ground fault of one wire or two wires in an effort to reconstruct the fire accident. The test results show that, owing to the instant operation of circuit breaker in the moment of short circuit or ground fault, the generated ignition energy is far less than necessary to start an ignition. Therefore it is concluded that electrical fire is highly unlikely if the electric system is protected by a circuit breaker with normal functions.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2006.06b
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• pp.209-214
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• 2006

This paper desires to assist ensuring of propriety clean-up equipment for clean-up shore or sea of pollution, there is not that responsible ability of a nation has an amount of skimmer or the length of boom. responsible ability of a nation must express overall evaluation what is considering quickly, system, and economizing in addition to an amount or clean-up equipment. responsible ability of a nation is complication and it's mutual relation of each other factor therefore responsible capacity of a nation is expressed using powersim with system dynamics theory.

• Journal of Korean Society for Quality Management
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• v.47 no.3
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• pp.453-465
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• 2019

Purpose: A main purpose is to increase the operational rate and reduce operating maintenance costs by Improving the durability of Blower of Military Armored Vehicle and Self-propelled Artillery. As a result, it is expected to improve the service quality of customers. Methods: After analyzing the cause of the stop of the blower, the improvement plans were established and the effectiveness of each improvement plans were verified by testing. Results: Mechanical, electrical and environmental factors affecting brush wear were reviewed, but it was difficult to specify the cause, which necessitated a review of the application of the BLDC motor. Conclusion: After applying the BLDC motor to the blower, tests proved that the existing blower can be replaced. It is expected that this study will help improve the durability life of similar equipment that is applied with Brushed DC motors as well as blowers.

• Journal of the Korea Institute of Military Science and Technology
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• v.22 no.5
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• pp.674-686
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• 2019

In this paper, we will discuss the absolute angular error control mode for the Gun/Turret driving system. The Gun/Turret driving controller receives absolute angular error calculated from the fire control system (FCS). Thus, the Gun/Turret driving controller is subjected to step command to cause residual vibration and system unstable. In order to reduce residual vibration and to ensure the system stability, we propose an error motion profile method with two types of trapezoidal and S-Curve. The validity of the proposed error motion profile method is confirmed via simulation by observing that the resulting position error, driving power, and power density satisfied the control performance.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.2
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• pp.363-370
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• 2021

The perimeter intrusion detection system is very important in physical security. In this study, a micro smart device (module) using MEMS sensor was developed in IoT environment for external intrusion detection. The outer intrusion detection system applying the smart device developed in this study is installed in various installation environments, such as barbed wire of various materials and shapes, the city center, the beach, and the mountain, so that it can detect external intrusion and its location as well as false alarms. As a smart sensor that can minimize the false alarm rate and economical construction cost, it is expected that it can be used for the safe operation of major facilities and prevention of disasters and crimes.

• Proceedings of the KSME Conference
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• 2001.06e
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• pp.772-776
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• 2001

The flow structures of turbulent shear layer behind oil fences with different tip configurations were investigated experimentally using flow visualization and PIV velocity field measurement. An oil fence was installed in a circulating water channel and the flow structure around the fence tip was mainly analyzed in this experiment. The four tip configurations tested in this experiment are knife edge; semi-circle edge, circular edge and rectangular edge. The 300 instantaneous velocity fields were measured using the single-frame PIV system and they were ensemble averaged to give the mean velocity field and spatial distribution of turbulent statistics. Free stream velocity was fixed at 10ms/sec and the corresponding Reynolds number based on the fence height was Re=4000. As a result, for the oil fence with rectangular edge, the streamwise velocity component was decreased. On the other hand it was increased for the oil fence with circular edge. For all four fences tested in this study, general flow pattern of the lower shear layer is analogous but the upper layer shows difference depending on the tip configurations. The oil fence with circular edge has more diffusive upper shear layer than that of the others. The shear layer of the oil fence with rectangular edge has relatively thin thickness. The oil fence with circular edge was found to be proper shape for tandem fence.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.3
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• pp.257-267
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• 2015

This paper presents a ultra-wideband sinuous antenna that operates in a whole frequency range (0.824~5.85 GHz) of Cellular/GSM-800, GSM900, ISM, GPS, DCS/GSM1800, PCS/GSM1900, WCDMA/UMTS/IMT2000, WiBro, WLAN and WiMax. The proposed antenna, which is composed of two sinuous arms, is designed as a self-complementary structure in order to have frequency-independent characteristics. It also uses a wideband balun of Klopfenstein taper structure to match to $50{\Omega}$. Experimental results show that the -10 dB return loss bandwidth of the proposed antenna is 5.24 GHz that ranges from 0.76 to 6 GHz, which covers all the frequency bands of the various wireless services. Within the entire operating frequency range, the measured radiation patterns in both E-plane and H-plane show nearly constant bidirectional broadside beams and the maximum antenna gain is measured to fall between 2.32~6.01 dBi.

• Journal of the Korea Furniture Society
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• v.20 no.4
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• pp.307-316
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• 2009

Seoul, the capital of Korea, is worldwide city; Seoul is 600 year-old city as a capital and more than 10 millions of population live in Seoul, Image of Seoul has began to be known to the peoples in the world through 1988 Seoul Olympic Games and 2002 World Cup. However, in the public design and trees lining street system, Seoul hasn't been escaped from the image of a city which lacks of the characterization in the culture and identity aspects. This paper applied a protective fence designing simulation for Cultural Street in Seoul to develop much more the identity of Seoul and characterization of local culture. Also, It's examined and analyzed R&D data, and applied traditional patterns to design to set developmental capacity of design and a direction of fence design in the past, present and future. It's analyzed the present condition of domestic manufacturers and examples for installation, selected randomly 7 places of domestic cultural places as an alternative to compare the previous design to the present design with 3D design and photos composing method, and developed the related situation. Also, It's visualized this method to let the citizens and all levels of society determine the design. besides that, developed the traditional patterns to apply the patterns to the design, considering the characteristic of each region and characteristic of each road. It's suggested this fence design to apply the image of advanced Korea and Seoul as a creative cultural city, and the international status of Korea and Seoul to the trees on the historical and traditional street. Also, put an importance to bring the identity of Seoul and Korea in the world into relief.

• The Journal of the Korea Contents Association
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• v.20 no.8
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• pp.538-546
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• 2020

This study uses a epidemic film that is being re-illuminated due to the recent appearance of COVID-19. In particular, The flu, Train to Busan, and Deranged are representative works of the "Epidemic Genre" in domestic disaster films, and their performance reports are different. Researcher set the pandemic film as one aspect of the genre film, and analyzed and compared three films in terms of three elements of the genre film: formula, convention, and iconography. An important element in the epidemic film was the improvement of reality through 'suspension of suspense' and 'ambiguity in the epidemic setting'. Lastly, Researcher hope the Korean film industry will develop more deeply through the "Epidemic Genre," a new genre of Korean films that has been spotlighted by the COVID-19 incident.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.6
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• pp.16-22
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• 2004

Unsteady vortex shedding behind a rectangular cylinder near a wall influences both increasing of drag and dynamic stability of heavy vehicle, bridge or building. Incompressible Averaged Navier-Stokes equation with modified ${\varepsilon}-SST$ turbulence model is adapted for investigating the flow field between the rectangular cylinder and the wall. In case the vortex shedding happens, not only the averaged maximum velocity is higher than other cases, but the position of the maximum velocity is closer to the lower surface of rectangular cylinder. On this study, it is confirmed that the vortex shedding behind a rectangular cylinder can be suppressed by the passive control method added by horizontal and vertical fences to the lower surface of rectangular cylinder.