• Journal of Radiation Protection and Research
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• v.28 no.2
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• pp.97-108
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• 2003

A three-dimensional wind field model based on the variational technique has been developed for estimating the overall wind patterns over a complex terrain. The three-dimensional elliptic partial differential equations on Cartesian and terrain-following coordinates have been established to obtain the Lagrangian multiplier and the adjusted wind velocity. The simulations were performed to evaluate the variations of the velocity vectors on the hemisphere, half-cylinder, and saddle type obstacles. Also, the wind field model in the terrain-following coordinate has been applied for evaluating the characteristics of wind patterns according to the variations of Gauss precision moduli on the hemispheric topography. The results showed that the horizontal and vertical wind components were strongly governed by the selection of the values of Gauss precision moduli.

• Journal of Radiation Protection and Research
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• v.28 no.1
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• pp.1-8
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• 2003

The periodic safety review of operational nuclear power plants requires that the plants should keep a well organized environmental monitoring program. The past records of environment monitoring data were analyzed. and the tritium concentrations of the samples in the surface and ground water around Kori site were measured. It was shown that the tritium concentrations around the Kori site were slightly higher than that of natural background. The change of background tritium concentration was estimated through a numerical modeling. Two different versions of 7 compartments model - the world and the northern hemisphere - defined in NCRP-62 were modeled for the global tritium cycling. The numerical solution of the model was obtained using a computer program, AMBER. The four cases of tritium source-terms into the atmosphere were considered. The results showed that the tritium concentration in the surface soil water was higher than that in sea water or surface stream water. Also, it was shown that the tritium produced by the interaction between cosmic rays and the gases were the major source of tritium, and the tritium produced by nuclear weapon test decreased considerably.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.11 no.2
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• pp.13-26
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• 2001

This paper presents the network security modeling methodology and simulation using the hierarchical and modular modeling and simulation framework. Recently, Howard and Amoroso developed the cause-effect model of the cyber attack, defense, and consequences, Cohen has been proposed the simplified network security simulation methodology using the cause-effect model, however, it is not clear that it can support more complex network security model and also the model-based cyber attack simulation. To deal with this problem, we have adopted the hierarchical and modular modeling and simulation environment so called the System Entity Structure/Model Base (SES/MB) framework which integrates the dynamic-based formalism of simulation with the symbolic formalism of AI. Several simulation tests performed on sample network system verify the soundness of our method.

• The Journal of the Korea Contents Association
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• v.22 no.9
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• pp.104-112
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• 2022

The pandemic caused by the COVID-19 virus, which has lasted for the past three years, has changed society and the way people live in many ways. These changes also affect cyberspace, so the pre-pandemic information security model and standards have limitations when applied to the current situation. In this paper, a new method to improve the information security model of public institutions was proposed in consideration of various situations in the new normal era. In other words, through the proposed information security model, the possibility of external intrusion is blocked in advance through the policy and technical supplementation of remote work, which is a weakness of the existing information security operation of public institutions. Also, how to prevent abnormal authentication attempts by building a secure VPN environment, how to prevent social engineering cyber attacks targeting fear and uncertainty caused by COVID-19, and how to use a smooth network and create a remote work environment. For this purpose, methods for securing service availability were additionally presented.

• Convergence Security Journal
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• v.24 no.2
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• pp.9-17
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• 2024

This paper examines the security threats to enterprise Generative Artificial Intelligence systems and proposes countermeasures. As AI systems handle vast amounts of data to gain a competitive edge, security threats targeting AI systems are rapidly increasing. Since AI security threats have distinct characteristics compared to traditional human-oriented cybersecurity threats, establishing an AI-specific response system is urgent. This study analyzes the importance of AI system security, identifies key threat factors, and suggests technical and managerial countermeasures. Firstly, it proposes strengthening the security of IT infrastructure where AI systems operate and enhancing AI model robustness by utilizing defensive techniques such as adversarial learning and model quantization. Additionally, it presents an AI security system design that detects anomalies in AI query-response processes to identify insider threats. Furthermore, it emphasizes the establishment of change control and audit frameworks to prevent AI model leakage by adopting the cyber kill chain concept. As AI technology evolves rapidly, by focusing on AI model and data security, insider threat detection, and professional workforce development, companies can improve their digital competitiveness through secure and reliable AI utilization.

• The Journal of the Korea Contents Association
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• v.20 no.6
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• pp.90-98
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• 2020

Modern vehicles are evolving from manual to automatic driving. As the ratio of electrical equipment and software increases inside the vehicle, vehicles that support autonomous driving are becoming another open computer system that can communicate with the outside. The safety of the vehicle means the safety of both the passenger and the non-passenger. It is not clear whether the safety problem of ultimate autonomous vehicles can be solved by the current solution of computer systems related to fault tolerance and security. Autonomous vehicles should not be dangerous to people after they are released to the market, so it is necessary to proactively diagnose all the risks that can be predicted with current technology. This paper examines the current developments of autonomous vehicles and analyzes their dangers that threaten driving safety, as well as their countermeasures.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.28 no.5
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• pp.1247-1258
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• 2018

The Cyber Kill Chain originally proposed by Lockheed Martin defines the standard procedure of general cyber attacks and suggests tailored defensive actions per each step, eventually neutralizing the intent of the attackers. Defenders can effectively deal with Advanced Persistent Threat(APT)s which are difficult to be handled by other defensive mechanisms under the Cyber Kill Chain. Recently, however, social engineering techniques that exploits the vulnerabilities of humans who manage the target systems are prevail rather than the technical attacks directly attacking the target systems themselves. Under the circumstance, the Cyber Kill Chain model should evolve to encompass social engineering attacks for the improved effectiveness. Therefore, this paper aims to establish a definite concept of Cyber Kill Chain for social engineering based cyber attacks, called Social Engineering Cyber Kill Chain, helping future researchers in this literature.

• Journal of Radiation Protection and Research
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• v.2 no.1
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• pp.38-46
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• 1977

오늘날 에너지 공급(供給)을 위한 새로운 해결책(解決策)의 하나로서 등장(登場)한 원자력발전소(原子力發電所), 재래(在來)의 X선(線) 진료(診療) 이외(以外)에 의학계(醫學界)에 도입(導入)된 방사선원(放射線源), 그리고 각종(各種) 전자생산품(電子生産品) 등(等)의 증가현상(增加現象)은 방사선(放射線) 방어(防禦) 문제(問題)와 관련(關聯)하여 보건의학분야(保健醫學分野)에서 종사(從事)하는 사람들에게 지대(至大)한 관심(關心)거리가 되고있다. 그래서, 우선(于先) 방사선(放射線)에 관(關)한 사항(事項)중에서 가장 기초(基礎)가되는 방사선량계측(放射線量計測)에 있어서 그 양(量)과 단위(單位) 문제(問題)가 체계적(體系的)으로 서술(敍述)되었다. 즉(卽) 방사선(放射線)이 인체(人體)에 끼칠 수 있는 해(害)로운 영향(影響)에 그 주안점(主眼點)을 두어 조사선량(照射線量), 흡수선량(吸收線量), 선량당량(線量當量), 그리고 그들의 관계(關係) 및 방사능등(放射能等)에 관(關)하여 토론(討論)되었다. 특(特)히 조사선량률(放射線量率), X는 비(比)감마선선상수(線常數), ($\Gamma$)를 포함(包含)하는 함수(函數)로 표현(表現)되었고, 끝으로 인체(人體) 내부(內部)에 축적(蓄積)된 방사능(放射能)으로부터의 영향(影響)에 의(依)한 이른바 생물학적효과(生物學的效果) (Somatic or Genetic Effects)와 관련(關聯)되는 내부흡수선량율(內部吸收線量率)은 평형흡수선량상수(平衡吸收線量常數)($\Delta_i$)와 흡수율($F_i$)를 포함(包含)하는 수학적(數學的) 모델로 소개(紹介)되었다. 한편 방사능(放射能)은 방사선원(放射線源) 물질(物質)의 자연붕괴율(自然崩壞率)이므로 다른 방사선량(放射線量)들 즉(卽) 조사선량(照射線量), 흡수선량(吸收線量)그리고 선량당량(線量當量)과는 별도(別途)로 취급(取扱)하였음을 부언(附言)한다.

• Proceedings of the Korea Society of Poultry Science Conference
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• 2003.05a
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• pp.73-82
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• 2003

본 연구에서는 국내 종계의 생산성 저하요인들을 평가·분석하였으며, 국내사육 종계의 실질적인 생산성을 극대화 시킬 수 있는 방안을 제시하고자 시험을 수행하여 다음과 같은 결론을 얻었다. 1. 혈청검색에 의한 품종별 종게군 질병 모니터링을 실시 한 결과, SE, MS 등 2종의 난계대성 세균성 질병과 REV, APV, CAV, ORT, REO 등 5종의 만성소모성 질병을 유발하는 질병이 종계군의 산란기에 감염되어 이들이 단독 또는 중복감염되어 나타나는 피해가 예상되었으며, 이들의 감염을 효과적으로 예방 할 수 있는 백신의 개발 및 도입의 필요성이 대두되었다. 2. 집중관리 모니터링 대상농장에 대한 ND, IB, IBD 등 3종의 생독백신에 대한 접종효능을 평가해 본 결과 산란종계, 육용종계를 막론하고 전반적으로 니플급수기를 이용한 음수접종법 적용시 5주령 이하 계군에 2내지 3회의 음수접종을 실시하였음에도 불구하고 항체가 거의 형성되지 못하거나 매우 불균일한 면역반응이 나타나는 것으로 조사되어 국내 야외농장에 대한 분무접종 유도 등 기존의 백신접종법에 대한 시급한 개선대책 마련이 요구되었다. 3. 육성기 및 산란기 종계 질병·위생관리 프로그램 확립을 위하여 ND, IB, IBD에 대한 개선된 백신접종 프로그램을 모델계군에 적용한 후, 주령별로 생독백신 접종효능을 조사한 결과 백신접종 후 ND, IB, IBD에 대한 평균 항체가와 항체의 균일도 (%CV)가 표준 목표치 이상 상승하여 개선의 효과를 볼 수 있었다. 4. 산란기 종계 질병·위생관리 프로그램 확립을 위하여 실시된 변이형 IB에 대한 방어능 시험결과 정기적인 Mass type IB 생독백신의 분무접종은 국내 유행 호흡기형 IBV 유전형 VI에 대한 방어효과는 다소 떨어지는 것으로 조사되어 국내분리주를 이용한 IB 생독백신의 개발이 요구되었다. 5. 종계장 살모넬라 및 마이코플라즈마 조기 검출을 위하여 실시한 종계장 살모넬라 및 마이코플라즈마 환경 모니터링 실시 결과 기존의 평판응집반응이나 ELISA에 의한 혈청검색법에 비하여 검출효율이 매우 높은 것으로 조사되어 향후 국내 종게군에 대한 살모넬라 및 마이코플라즈마 조기검출과 방제연구에 큰 도움이 될 것으로 사료되었다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.4C
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• pp.451-457
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• 2006

A peer-to-peer(P2P) network is inherently vulnerable to malicious attacks from participating peers because of its open, flat, and autonomous nature. This paper addresses the problem of effectively defending from active attacks of malicious peers at bootstrapping phase and at online phase, respectively. We propose a secure membership handling protocol to protect the assignment of ID related things to a newly joining peer with the aid of a trusted entity in the network. The trusted entities are only consulted when new peers are joining and are otherwise uninvolved in the actions of the P2P networks. For the attacks in online phase, we present a novel message structure applied to each message transmitted on the P2P overlay. It facilitates the detection of message alteration, replay attack and a message with wrong information. Taken together, the proposed techniques deter malicious peers from cheating and encourage good peers to obey the protocol of the network. The techniques assume a basic P2P overlay network model, which is generic enough to encompass a large class of well-known P2P networks, either unstructured or not.