• Journal of Aerospace System Engineering
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• v.10 no.4
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• pp.26-34
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• 2016

In a number of industries, porous insulations have been frequently used, reducing thermal insulation space through excellent performance of the thermal insulation's characteristics. This paper suggests an effective thermal conductivity prediction model. Firstly, we perform a literature review of traditional effective thermal conductivity prediction models and compare each model with experimental heat transfer results. Furthermore, this research defines the effectiveness of thermal conductivity prediction models using experimental heat transfer results and the Zehner-Schlunder model. The newly defined effective thermal conductivity prediction model has been verified to better predict performance than other models. Finally, this research performs a transient heat transfer analysis of a thermal protection system with a porous insulation in a high speed vehicle using the finite element method and confirms the validity of the effective thermal conductivity prediction model.

• Journal of Convergence for Information Technology
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• v.8 no.1
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• pp.139-145
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• 2018

Ransomeware is a kind of malware. Computers infected with Ransomware have limited system access. It is a malicious program that must provide a money to the malicious code maker in order to release it. On May 12, 2017, with the largest Ransomware attack ever, concerns about the Internet security environment are growing. The types of Ransomware and countermeasures to prevent cyber terrorism are discussed. Ransomware, which has a strong infectious nature and has been constantly attacked in recent years, is typically in the form of Locky, Petya, Cerber, Samam, and Jigsaw. As of now, Ransomware defense is not 100% free. However, it can counter to Ransomware through automatic updates, installation of vaccines, and periodic backups. There is a need to find a multi-layered approach to minimize the risk of reaching the network and the system. Learn how to prevent Ransomware from corporate and individual users.

• Journal of Internet Computing and Services
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• v.18 no.5
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• pp.9-15
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• 2017

In the whole world the Attack Technologies of cyber warfare in modern society are growing faster and complicated. The frequency of the new attacks is shorter than before day by day. The defense technologies and experts against these attacks are very few. One of answers to solve these problems is the cyber range as a test-bed to prepare the cyber warfare considered by many countries. This paper examines the foreign cases and similar systems, collects and analyzes various attributes for cyber range. Finally it refines them through system engineering processes. In these processes missions and concepts for administration are set with architecture framework. The logical architecture is designed. Based on designed architecture two goals, defense technologies and procurement of experts, are established. And it shows effective and persistent administration of cyber range.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.79-79
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• 2018

하천시설물 설계, 시공 및 관리에 재료에 따른 호안이나 제방의 보호능력이 저하되어 설계 시 예상하지 못한 조건에서 쉽게 파손될 수 있으며, 하천환경의 변화를 야기시킬 수 있다. 제방 표면재료는 제외 비탈면의 침식 방지를 목적으로 사용되는 재료로 주로 호안블록. 식생 매트, 사석, 돌망태, 식생등이 주로 사용되며 국내에서는 2000년대 이전에는 자연 흙사면의 식생, 돌망태, 단순 돌기형 콘크리트 블록 등이 주로 사용되었으며 2000년대 이후에는 하천환경을 고려하여 식생의 생장이 가능한 친환경 호안 블록 및 식생 매트의 적용이 일반적인 실정이다. 제방의 수리적 설계를 위해서는 표면 재료의 수리 특성, 즉, 조도계수 및 한계 유속, 한계 소류력이 제시되어야 하는데 이는 실험을 통해서 결정되어야 한다. 때문에 본 연구에서는 자연형 하상재료를 이용하여 바이오 폴리머 첨가시 증가하는 방어능력에 대한 향상도를 평가하는 실험적 평가 방법을 제안하기위해 홍수시 수리조건을 반영하여 상류에서부터 사류까지 다양한 유속범위에 따른 세굴 및 침식에 대한 실험을 진행하였다. 본 연구에서는 실험연구를 통해 연구에 사용된 재료 외 추가적인 재료에 대해서도 평가방법이 적용될 수 있도록 제방 재료의 안정성 평가시스템을 개발하였고, 안정성 평가를 위한 실험진행은 기 개발된 바닥응력을 직접측정하는 장치와 PIV시스템을 이용하여 수리특성을 측정하였다.(Park J.H. et al. 2016, Flow Measurment and instrumentation.) 이러한 측정 장치를 이용하여 바이오폴리머의 첨가에 유무에 따라 세굴에 대한 방어능력의 향상정도를 측정하고자 세굴 및 침식에 대한 평가 방법을 제시하고 있다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.10
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• pp.1525-1530
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• 2022

BGP(Border Gateway Protocol) is a routing protocol that is actively used in inter-AS routing on the Internet. However, BGP routing protocol is vulnerable to BGP hijacking attacks that hijack the network by impersonating normal BGP sessions. BGP Hijacking attacks can lead to causing intercept IP traffic or interference with the normal service operation. Recently, BGP hijacking attacks, which have often occurred overseas, have also occurred in Korea. It means threatening the security of the Internet. In this paper, we analyze the overall process of attack through representative attack cases and virtual scenarios of BGP hijacking and based on the results of analyzing the application status of security technology to prevent BGP hijacking attacks by Korea and global major ISPs. It covers the technical proposal of ISPs and autonomous system operators should take to defend against BGP hijacking attacks.

• Journal of the Society of Naval Architects of Korea
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• v.60 no.1
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• pp.57-64
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• 2023

Recently, the increased use of anti-ship guided missiles, a weapon system that detects and attacks targets in naval engagement, has come to pose a major threat to the survivability of ships. In order to improve the survivability of ships in response to such anti-ship guided missiles, many studies of means to counteract them have been conducted in militarily advanced countries. The integrated survivability of a ship can be largely divided into susceptibility, vulnerability, and recoverability, and is expressed as the conditional probability, if the ship is hit, of damage and recovery. However, as research on susceptibility is a major military secret of each country, access to it is very limited and there are few publicly available data. Therefore, in this study, a possibility of estimating the susceptibility of ships using an anti-air defense system corresponding to anti-ship guided missiles was reviewed. To this, scenarios during engagement, weapon systems mounted to counter threats, and maximum detection/battle range according to the operational situation of the defense weapon system were defined. In addition, the effectiveness of the anti-air defense system and susceptibility was calculated based on the performance of the weapon system, the crew's ability to operate the weapon system, and the detection probability of the detection/defense system. To evaluate the susceptibility estimation feasibility, the sensitivity of the detailed variables was reviewed, and the usefulness of the established process was confirmed through sensitivity analysis.

• Proceedings of the Korean Information Science Society Conference
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• 2006.06c
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• pp.304-306
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• 2006

21세기 정보혁명을 바탕으로 전쟁의 양상은 정보전, 네트워크 및 컴퓨터 중심의 사이버전과 같은 새로운 전쟁 패러다임으로 변화하고 있다. 이러한 정보전에 대비하여 국방정보체계에 다양한 정보보호시스템을 설치하여 사용하고 있다. 그러나 국방정보체계 환경에 현재까지 배치된 정보보호시스템들은 침해 사고에 대한 탐지 및 보고 등의 수동적인 대응만을 지원한다. 그러므로 발생한 공격에 대한 대응을 마련하더라도 동일한 공격자가 동일한 목표 시스템에 대하여 또 다른 공격 기술을 이용하여 재침입이 가능하다. 이를 방어하기 위하여 공격에 대한 능동적인 대응이 필요하다. 대표적인 능동 대응 기술인 침입자 역추적은 시스템 및 네트워크에 대하여 공격을 시도하는 침입자의 네트워크 상의 실제 위치를 추적하는 기술이다. 침해 사고를 근본적으로 차단하기 위하여 침입자의 실제 신분 확인이 필수적이다. 이를 위하여 본 논문에서는 침입자 역추적 기술을 분석하고 국방정보체계 환경을 위한 세션분석기반의 침입자 역추적 기술을 제안한다. 또한 이 기술을 기반으로 구현한 침입자 역추적 시스템을 소개한다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.358-363
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• 2017

The high intercept probability depends on optimization of the system, which consists of target detection, tracking system, missile system and so on. To reduce the complexity of global optimization of the system performance, simplification of the relative dependances of each sub-system is done and design parameters for DACS configuration are identified. The conceptual design process is addressed based on the requirement of the design parameters and new methodology is suggested for higher performance.

• Journal of IKEEE
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• v.26 no.3
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• pp.389-395
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• 2022

With the evolution of technology, cyber physical systems (CPSs) are being upgraded, and new types of cyber attacks are being discovered accordingly. There are many forms of cyber attack, and all cyber attacks are made to manipulate the target systems. A representative system among cyber physical systems is a cyber physical power system (CPPS), that is, a smart grid. Smart grid is a new type of power system that provides reliable, safe, and efficient energy transmission and distribution. In this paper, specific types of cyber attacks well known as false data injection attacks targeting state estimation and energy distribution of smart grid, and protection strategies for defense of these attacks and dynamic monitoring for detection are described.

• Journal of Korea Water Resources Association
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• v.43 no.1
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• pp.51-65
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• 2010

We suggest a simple and practical flood forecasting and warning system, which can predict change in the water level of a river in a small to medium-size watershed where flash flooding occurs in a short time. We first choose the flood defense target points, through evaluation of the flood risk of dike overflow and lowland inundation. Using data on rainfall, and on the water levels at the observed and prediction points, we investigate the interrelations and derive a regression formula from which we can predict the flood level at the target points. We calculate flood water levels through a calibrated flood simulation model for various rainfall scenarios, to overcome the shortage of real water stage data, and these results as basic population data are used to derive a regression formula. The values calculated from the regression formula are modified by the weather condition factor, and the system can finally predict the flood stages at the target points for every leading time. We also investigate the applicability of the prediction procedure for real flood events of the Jungnang Stream basin, and find the forecasting values to have close agreement with the surveyed data. We therefore expect that this suggested warning scheme could contribute usefully to the setting up of a flood forecasting and warning system for a small to medium-size river basin.