• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.49 no.5
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• pp.355-363
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• 2021

Heat resistance performance evaluation and thermal analysis were performed to confirm the applicability of the lyocell-based carbon/phenolic composite material for heat-resistant parts for aerospace. Heat resistance performance evaluation of carbon/phenolic was conducted by Thermal Protection Evaluation Motor (TPEM). In this paper, boundary layer integration code considering the boundary layer analysis of combustion gas and MSC-Marc 2018 considering ablation and thermal pyrolysis were used for the thermal analysis. The ablation and thermal insulation performance were analyzed by the pressure curve of test motor and the cut carbon/phenolic specimens. The thermal response of the lyocell-based carbon/phenolic material was similar to that of the rayon-based carbon/phenolic material. Based on the results through the combustion test, the applicability of heat-resistant parts for aerospace to which domestic lyocell-based carbon fibers were applied was confirmed.

• Journal of the Korea Institute of Military Science and Technology
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• v.23 no.5
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• pp.475-484
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• 2020

Individual curing process of each layer in two resin composites can be caused the separation between two layers. In this study, co-curing process for two resin composites is suggested to improve the inter-layer bonding. Glass fiber reinforced composites with phenolic and epoxy resins were manufactured by co-curing process, and several types of glass/phenolic composites were considered to confirm the application on two resin composites. Experiments for smoke resistance, scratch resistance and flexural strength were carried out to verify requirements corresponding to thermal and mechanical environments. It was validated that two resin composites with phenolic resin impregnated prepreg exhibits good thermal and mechanical characteristics, and it can serve as highly effective composite structures in aerospace and many industry areas.

• Journal of the Korea Society for Simulation
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• v.29 no.2
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• pp.49-61
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• 2020

It is important to operate a limited number of interceptors effectively to counter ballistic missile threats. The existing interceptor operating method determines the number of interceptors according to the level of TBM (Theater Ballistic Missile) engagement effectiveness applied to a defended asset. It can cause either excessive interceptor waste compared to the intercept probability or the intercept probability decrease. Thus, interceptor operating method must be decided considering the number of ballistic missiles, intercept probability and cost. This study proposes a mathematical model to improve the existing interceptor operating method. In addition, the efficiency indicator is proposed for trade-off between intercept probability and cost. As a result of the simulations, the mathematical model-based interceptor operating method can achieve better results than the existing interceptor operating method.

• Journal of the Korea Institute of Military Science and Technology
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• v.19 no.3
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• pp.330-338
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• 2016

Impregnation of shear-thickening fluid(STF) into high-strength fabrics makes a considerable improvement on the ballistic performance of fabric armors. Understanding dissipation augmentation due to shear thickening effects on yarn-yarn and yarn-projectile friction is of great importance in liquid armor research. This paper takes a shearthickening effect into account in numerical simulations by using a velocity-dependent friction model. Impact simulations were performed to validate the friction model as well as to evaluate the ballistic performance of STF-fabrics. Impact simulations on neat fabrics were also conducted to provide baseline results for comparison.

• IE interfaces
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• v.22 no.3
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• pp.287-301
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• 2009

The purpose of this study is to develop a mid and long-term roadmap for "Commercial and Military Collaboration Standardization(CMCS) program." We developed three layer's roadmap through systematical process. The roadmap is composed of four targets, eight projects and forty-six tasks. To evaluate the quality of the roadmap, we applied checklist method and statistical analysis. Consequently, the quality is positive and it shows that the roadmap could apply for CMCS program. In addition, it is expected to contribute to the standardization between military supplies and commercial products.

• Journal of Aerospace System Engineering
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• v.15 no.6
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• pp.59-65
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• 2021

In this paper, the transmission characteristics of the multi-layered composite material with wire mesh and honeycomb core for aircraft applications have been analyzed with the proposed method. The proposed method converts the conductive wire mesh into effective layer, while for the dielectric honeycomb core, effective permittivity has been derived based on volume fraction with the proposed method. The proposed method has been verified through comparison with full-wave simulation and revealed excellent. In addition, the calculation time of the proposed method is a few order of magnitude faster in comparison with the full-wave simulation.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.22 no.3
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• pp.679-689
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• 2012

There were clear differences between the DDoS attack on 7th July 2009 and the rest of them prior to the attack. Despite It had emitted relatively small sized packets per infected PC, the attack was very successful making use of HTTP Flooding attack by aggregating small sized packets from the well sized zombie network. As the objective of the attack is not causing permanent damage to the target system but temporal service disruption, one should ensure the availability of the target server by deploying effective defense strategy. In this paper, a novel HTTP based DDoS defense mechanism is introduced with capacity based defense-in-depth strategy.

• Journal of the Korea Institute of Military Science and Technology
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• v.27 no.2
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• pp.285-293
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• 2024

This paper describes the interception using fine fragments and particles to hypersonic vehicles which have a vulnerability in thermal and pressure during glide-phase flight. This interception concept is based on the fast relative velocity and the flight vulnerability of hypersonic vehicles. For the density calculation of fragmentation and particle in interception, error analysis of end-phase was performed including radar, intercept missile and target maneuvering errors. In relation to the vulnerability and error analysis, the penetration characteristics of fine fragments in high temperature were analyzed. Presented the interception in glide-phase could be applied to the concept of horizontal multi-layer defense to hypersonic vehicles.

• Proceedings of the Korean Society of Computer Information Conference
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• 2010.07a
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• pp.525-526
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• 2010

2000년 대규모 DDoS 공격이래, 2009년 7월 7일 국가주요정부기관 및 인터넷 포털, 금융권 등의 웹사이트 대상으로 1차, 2차, 3차로 나누어 대규모 사이버 공격이 발생하였다. 지속적으로 발전되는 행태를 보이고 DDoS 공격에 대해 본 논문에서는 계층적인 침입탐지시스템을 설계하였다. 네트워크 패킷을 분석하기 위해 e-Watch, NetworkMiner등의 패킷, 프로토콜 분석도구를 이용하여 TCP/IP의 Layer별 공격을 분석한 후 패킷의 유입량, 로그정보, 접속정보, Port, Address 정보를 분석하고 계층침입에 대한 방어를 수행하도록 설계하였다. 본 논문은 DDoS(Distributed Denial of Service)에 대한 패킷 전송에 대해 계층적인 방어를 통해 보다 안정적인 패킷수신이 이루어진다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.277-280
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• 2010

Network based on the OSI 7 Layer communication protocol is implemented, and the Internet TCP / IP Layer Based on the vulnerability is discovered and attacked. In this paper, using the programs on the network Layer Scanning conducted by the Layer-by each subsequent vulnerability analysis. Layer by Scanning each vulnerability analysis program to analyze the differences will be studied. Scanning for the studies in the program reflects the characteristics of the Scanning Features of way, and security countermeasures by each Layer is presented. The results of this study was to analyze its vulnerability to hackers and security for defense policy as the data is utilized to enhance the security of the network will contribute.