• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.4
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• pp.113-120
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• 2005

In order to investigate the characteristics of penatration and the effect of surface treatment in A15052-H34, Al5082-Hl31 and titanium alloy laminates which were treated by anodizing and PVD(Physical Vapor Desposition) method, ballistic tests were conducted. Thickness of surface membrane in A15052-H34, Al5082-Hl31, were $25{\mu}m$ and that of titanium $0.9{\mu}m$ respectively. Surface hardness test was conducted using micro Vicker's hardness tester. Resistance to penetration is determined by the protection ballistic limit(V50), a statistical velocity with $50\%$ probability for complete penetration. Fracture behaviors and ballistic tolerance, described by penetration modes, are observed from the results of V50 test and Projectile Through Plate(PTP) test at velocities greater than protection ballistic limit, respectively. Present experimental results derived from this research help to optimize laminate impact behavior by varing the laminate thickness and surface treated materials.

• 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.

• Korean Security Journal
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• no.19
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• pp.67-103
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• 2009

Objectives of this study is develop security services through determinants analysis on the efficiency of security works regarding security and guarding business in Korea because nowadays the modern society like Korea let alone all over the world faces the increase of dangerous factors in every security field of the human societies, and also it is the very present situation that an individual's life even the national security itself can be at the risk without guaranteeing the efficiency of the security services. For this purpose, this study reviewed related documents, surveyed and interviewed security personnels to identify what the potentially influential factors are in both the public and private security organizations regarding the efficiency of present security services and organizations, and what differences are. Also, comparing the public and private security sectors, this study intended to suggest policy agendas how to enhance the efficiency of security services in the future. This study surveyed the 177 agents and former agents of the Presidential Security Service(PSS) for the public security sector, and also surveyed, interviewed, and internet-based polled 821 randomly selected personnels for the private security sector. This research showed that regarding the efficiency of the security services number of independent variables which had positive responses in the public security sector was more than that in the private security sector. Among the 21 questions regarding this issue, there were all of 21 positive responses in the public security sector while there were 18 negative responses in the private security sector. As a result of synthesizing all the answers of the both sides, it is possible to understand that mostly the ratio of the positive response was much higher. In the public security service, statistically significant variables were budget support for events, prior access of information, an integrated teamwork training, organizational atmosphere, morale of organization personnel. However, practical training of the security service and mutual communication showed unexpectedly negative(-) signs. In the private security service, statistically significant variables were budget support for events, integrated teamwork training, socially friendly atmosphere, compensation for the personnels, bullet-proof equipments and vehicles, mood of organization, personnel recruit and disposition, unexpected incidents and basic attitude for security services. In sum, while organizational personnel variables and organizational management variables were significant in the public security service, some organizational management variables and all socio-environment variables were statistically significant at 5% significance level.