• Information and Communications Magazine
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• v.29 no.2
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• pp.39-45
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• 2012

V2X 차량 안전 시스템은 ITS 환경에서 주행하는 모든 차량들이 V2V 혹은 V2I 기반의 협력통신을 통해 안전 서비스를 제공하는 기술이다. 이는 실제 도로환경에서의 실험, 즉 Field Operational Tests(FOTs)를 통한 검증과 평가 수행이 요구된다. 그러나, 일반적으로 실 도로환경에서 시스템 및 서비스에 대한 검증과 평가는 많은 시간과 비용을 필요로 한다. 따라서 실제 도로 주행 테스트 전에 V2X 안전 서비스의 기본적인 성능을 검증할 V2X 시뮬레이션 방안이 필요하다. 본 논문에서는 국외의 V2X 시뮬레이터 기술 개발 동향과 함께 차량 간 통신 시뮬레이션 분야에서 연구되고 있는 주요 이슈들을 알아보고 이를 극복하기 위한 연구 방호별 제시한다.

• Journal of the Korea Concrete Institute
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• v.22 no.1
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• pp.93-102
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• 2010

Recently, FRP usage for strengthening RC structures in civil engineering has been increasing. Especially, the use of FRP to strengthen structures against blast loading is growing rapidly. To estimate FRP retrofitting effect under blast loading, blast tests with nine $1,000{\times}1,000{\times}150\;mm$ RC panel specimens, which were retrofitted with carbon fiber reinforced polymer (CFRP), Polyurea, CFRP with Poly-urea and basalt fiber reinforced polymer (BFRP) have been carried out. The applied blast load was generated by the detonation of 15.88 kg ANFO explosive charge at 1.5 m standoff distance. The data acquisitions not only included blast waves of incident pressure, reflected pressure, and impulse, but also included central deflection and strains at steel, concrete, and FRP surfaces. The failure mode of each specimen was observed and compared with a control specimen. From the test results, the blast resistance of each retrofit material was determined. The test results of each retrofit material will provide the basic information for preliminary selection of retrofit material to achieve the target retrofit performance and protection level.

• Journal of IKEEE
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• v.23 no.4
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• pp.1461-1464
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• 2019

In this paper, we propose the development of embedded board for integrated radiation exposure protection fireman's life-saving alarm capable of location tracking and radiation measurement. The proposed techniques consist of signal processing unit, communication unit, power unit, main control unit. Signal processing units apply shielding design, noise reduction technology and electromagnetic wave subtraction technology. The communication unit is designed to communicate using the wifi method. In the main control unit, power consumption is reduced to a minimum, and a high performance system is formed through small, high density and low heat generation. The proposed techniques are equipment operated by exposure to poor conditions, such as disaster and fire sites, so they are designed and manufactured for external appearance considering waterproof and thermal endurance. The proposed techniques were tested by an authorized testing agency to determine the effectiveness of embedded board. The waterproof grade has achieved the IP67 rating, which can maintain stable performance even when flooded with water at the disaster site due to the nature of the fireman's equipment. The operating temperature was measured in the range of -10℃ to 50℃ to cope with a wide range of environmental changes at the disaster site. The battery life was measured to be available 144 hours after a single charge to cope with emergency disasters such as a collapse accident. The maximum communication distance, including the PCB, was measured to operate at 54.2 meters, a range wider than the existing 50 meters, at a straight line with the command-and-control vehicle in the event of a disaster. Therefore, the effectiveness of embedded board for embedded board for integrated radiation exposure protection fireman's life-saving alarm has been demonstrated.

• Journal of the Korea Institute of Building Construction
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• v.13 no.6
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• pp.579-584
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• 2013

The stable fueling and water supply should be prerequisites to guarantee the operational sustainment of military command post. Meanwhile, in terms of the operational sustainment, it is verified that the current wave-guided below cutoff (WBC) system cannot satisfy the requirement of control associated with water supply and fueling within the command post. In this study, as the dielectric substance can block electromagnetic pulse (EMP), it was tried to identify the shielding effectiveness of the multi WBCs filled with water and diesel for attenuating the EMP effect using experiment based on the MIL STD 188-125-1. According to the experimental results, used water in the experiment show the shielding effectiveness from around 640 MHz frequency because of minerals contained in the water. Furthermore, it was noted that EMP attenuating strength of the WBC filled with diesel was enlarged from around 1,680 MHz frequency. Resultingly, it could be concluded that it is enough to supply stable water and diesel through the multi WBC to block EMP within the military command post for guaranteeing the military operations sustainment.

• Journal of the Korean Society of Propulsion Engineers
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• v.10 no.3
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• pp.53-59
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• 2006

This paper presents the IR-Lamp test results of evaluating heat protection performance and measuring of mechanical/thermal properties in the heat protection material of missile external surface. The results showed that increasing the contents of microballoons improved the heat protection performance, but the mechanical properties were deteriorated. Among the kinds of microballoons, Epoxy/Phenolic Microballoons mixture showed the best mechanical properties and low thermal conductivity. Epoxy/Cork mixture showed the best heat protection in the IR-Lamp test, though it has low mechanical properties and high thermal conductivity.

• Journal of the Korea Institute of Military Science and Technology
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• v.22 no.2
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• pp.151-161
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• 2019

In this study, to evaluate the High Altitude Electromagnetic Pulse(HEMP) protection performance of UHPC/CNT composites by the content of Carbon nanotubes(CNTs), Electromagnetic Shielding Effectiveness(SE) test was performed based on MIL-STD-188-125-1. And the results were verified by applying the Antenna theory. In the case of UHPC with a thickness of 200 mm mixed with 1 % CNT of cement weight, the SE was 28.98 dB at 10 kHz and 45.94 dB at 1 GHz. Then the Scabbing limit thickness for bullet proof was computed based on the result of compressive strength test which was 170 MPa, and it was examined whether it satisfied the HEMP protection criteria. As a result, the required HEMP shielding criteria were satisfied in all frequency ranges as well as the scabbing limit thickness was reduced by up to 43 % compared with that of ordinary concrete.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.25 no.6
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• pp.487-495
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• 2012

In order to prevent the high velocity bullet from penetration, aluminum alloy and RHA(Rolled Homogeneous Armour) steel, which have a high tensile and compressive strength, are usually used as the bullet-proof armor material. Although these materials have a good bullet proof performance, but not an area density which is a weight increasing factor of bullet-proof armor. Therefore, Mg(magnesium) alloy is a promising substitute for the traditional bullet-proof armor material due to the relatively low areal density. The spatial efficiency of Mg alloy, however, is inferior to the traditional material's, which is a volume(thickness) increasing factor of bullet-proof armor. In this study, we select the multi-layered hybrid armor which consist of Ceramic, with a high strength; Mg alloy, with a low areal density; Kevlar, with a high tensile strength-to-weight ratio; in order to make up for the poor spatial efficiency of Mg alloy. By predicting V50 of the multi-layered armor against 9mm FMJ(Full Metal Jarket). we show that the multi-layered armor have the capability in improving bullet-proof performance in the respect of the areal density, but also the spatial efficiency.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.5
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• pp.102-113
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• 2021

The deterioration environments caused by de-icing salt and airborne chlorides in the seashore, evaluated in the "Detailed guideline for safety and management practice of facilities (performance evaluation)", were reviewed in terms of penetrated chlorides into concrete on various road facilities. Target concrete structures, in this study, were 4 concrete barriers in Gangwon area, 3 concrete barriers and 1 retaining wall in Busan area, and 4 bridges in Gangwon-do, Seoul, Gyeonggi-do, and Busan. The deterioration environments were classified into three categories: direct and indirect de-icing salt attack, and airborne salt attack depending on the distance to seashore and the height of pier, and the penetrated chlorides in to concrete were analyzed. The results showed that (1) the regional deterioration environments were clearly classified by de-icing salt sprayed days (snowfall days), (2) the penetrated chlorides increased significantly when leakage occurred through slabs or expansion joints, and (3) the airborne chlorides affected to a height of 20 m concrete in the seashore, Busan. From these, it could be confirmed that the chloride ion penetration properties depend on the exposed aging environment, member location and height, and deterioration status, even on the same structure, so the selection of target members and location is very important in the inspection and maintenance. If the database of penetrated chlorides properties in various deterioration environments is constructed, it is expected that the proactive durability management on concrete structures will be possible in the field.

• Fire Science and Engineering
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• v.33 no.6
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• pp.43-52
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• 2019

A walk-down procedure for fire modeling of nuclear power plants, based on deterministic fire protection requirements, was developed. The walk-down procedure includes checking the locations of safety shutdown equipment and cables that are not correctly indicated on drawings and identifying the existence and location of combustibles and ignition sources. In order to verify the performance of the walk-down procedure developed in this study, a sample of important equipment and cables were selected for hypothetical multiple spurious operation (MSO) scenarios. In addition, the hypothetical fire modeling scenarios were derived from the selected safe shutdown equipment and cables and an actual walk-down was conducted. The plant information collected through the walk-down was compared to the information obtained from the drawings, so that the collected information may be used as input values for the fire modeling.

• Journal of the Korea Concrete Institute
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• v.28 no.2
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• pp.141-148
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• 2016

This paper employed finite element method (FEM) to study the dynamic response of Steel Fiber-Reinforced Concrete(SFRC) panels subjected to impact loading by spherical projectiles. The material properties and non-linear stress-strain curves of SFRC were obtained by compression test and flexural test. Various parametric studies, such as the effect of fiber volume fraction and thickness of panels, are made and numerical analyses are compared with experiments conducted. It is shown that protective performance of concrete panels will be improved by adding steel fiber. Area loss rates and weight loss rates are decreased with increasing fiber volume fraction. Also, penetration modes can be expected by FEM, showing well agreement with experiment. Results can be applied for designing the protection of military structures and other facilities against high-velocity projectiles.