• Carbon letters
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• v.25
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• pp.55-59
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• 2018

Carbon chain inserted carbon nanotubes (CNTs) have been experimentally proven having undergone pronounced property change in terms of electrical conductivity compared with pure CNTs. This paper simulates the geometry of carbon chain inserted CNTs and analyzes the mechanism for conductivity change after insertion of carbon chain. The geometric simulation of Pt doped CNT was also implemented for comparison with the inserted one. The results indicate that both modification by Pt atom on the surface of CNT and addition of carbon chain in the channel of the tube are effective methods for transforming the electrical properties of the CNT, leading to the redistribution of electron and thereby causing the conductivity change in obtained configurations. All the calculations were obtained based on density functional theory method.

• Proceedings of the IEEK Conference
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• 2002.06c
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• pp.131-134
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• 2002

As the increased use of computer, wired/wireless/mobile Internet, security in using Internet becomes a more important problem. Thus, biometric technology using physical and behavior characteristics of a person is hot issue. Many different types of biometric technologies of a person such as fingerprint, face, iris, vein, DNA, brain wave, palm, voice, dynamic signature, etc. had already been studied but remained unsuccessful because they do not meet social demands. However, recently many of these technologies have been actively revived and researchers have developed new products on various commercial fields. Dynamic signature verification technology is to verify the signer by calculating his writing manner, speed, angle, and the number of strokes, order, the down/up/movement of pen when the signer input his signature with an electronic pen for his authentication. Then signature verification system collects mentioned above various feature information and compares it with the original one and simultaneously analyzes to decide whether signature is forgery or true. The prospect of signature verification technology is very promising and its use will be wide spread in terms of economy, security, practicality, stability and convenience.

• Proceedings of the Korea Information Processing Society Conference
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• 2016.10a
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• pp.439-442
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• 2016

제한된 환경에서 로봇이 동적 장애물들에 대해 능동적으로 대처하며 목표한 지점까지 도달하기 위한 알고리즘을 제안한다. 로봇은 행동기반 시스템으로 만들어져 주변 장애물들을 자율적으로 회피한다. ex-agent는 공중에서 주변 환경들을 modeling 한 뒤 cell-map을 만들어 $A^*$알고리즘을 통해 이동 경로를 설정한다. 이동 경로와 로봇의 진행방향을 비교하여 회전 방향을 조언해준다. 로봇은 ex-agent 로부터 받은 조언과 센서값들을 조율하여 장애물들을 능동적으로 회피하며 목표 위치를 찾아갈 수 있다. 실험은 시뮬레이터를 통해 이루어졌으며 장애물들에 대해 원반한 회피율을 보였다.

• Journal of Information Processing Systems
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• v.12 no.3
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• pp.538-547
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• 2016

Cloud computing is a new style of computing in which dynamically scalable and reconfigurable resources are provided as a service over the internet. The MapReduce framework is currently the most dominant programming model in cloud computing. It is necessary to protect the integrity of MapReduce data processing services. Malicious workers, who can be divided into collusive workers and non-collusive workers, try to generate bad results in order to attack the cloud computing. So, figuring out how to efficiently detect the malicious workers has been very important, as existing solutions are not effective enough in defeating malicious behavior. In this paper, we propose a security protection framework to detect the malicious workers and ensure computation integrity in the map phase of MapReduce. Our simulation results show that our proposed security protection framework can efficiently detect both collusive and non-collusive workers and guarantee high computation accuracy.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.7
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• pp.2904-2918
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• 2020

With a huge demand for replicated content on the Internet, a new networking paradigm called information-centric networking (ICN) has been introduced for efficient content dissemination. In ICN, named content is distributed over the network cache and it is accessed by name instead of a location identifier. These aspects allow users to retrieve content from any of the nodes having replicas, and consequently 1) network resources are more efficiently utilized by avoiding redundant transmission and 2) more scalable services are provided by distributing server loads. However, in-network caching in ICN brings about a new type of security issues, called content poisoning attacks, where fabricated content is located in the network cache and interferes with the normal behavior of the system. In this paper, we look into the problems of content poisoning in ICN and discuss security architectures against them. In particular, we reconsider the state-of-the-art schemes from the perspective of feasibility, and propose a practical security architecture.

• Proceedings of the Korean Information Science Society Conference
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• 2007.10d
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• pp.27-30
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• 2007

초기의 웜은 감염 및 확산의 신속성을 중요시하였으나, 생존성은 고려하진 않았다. 하지만 보안도구(Anti-worm)의 발달에 따라 2004년 이후 대규모의 웜 확산에 의한 피해가 보고되지 않고 있다. 이에 웜도 보안도구를 회피하는 자기방어(Self-Defense) 기법을 개발하여 생존성을 증가시키면서 진화하고 있다. 본 논문은 현존하는 웜 자기방어 기법과 그 한계를 분석한 후 행동기반 탐지 기법을 우회하는 자기방어 기법을 제안하도록 하겠다.

• ETRI Journal
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• v.28 no.5
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• pp.692-695
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• 2006

Recently, there has been a constant barrage of worms over the Internet. Besides threatening network security, these worms create an enormous economic burden in terms of loss of productivity not only for the victim hosts, but also for other hosts, as these worms create unnecessary network traffic. Further, measures taken to filter these worms at the router level incur additional network delays because of the extra burden placed on the routers. To develop appropriate tools for thwarting the quick spread of worms, researchers are trying to understand the behavior of worm propagation with the aid of epidemiological models. In this study, we present an optimization model that takes into account infection and treatment costs. Using this model we can determine the level of treatment to be applied for a given rate of infection spread.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.11a
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• pp.665-666
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• 2009

정보통신 기술과 저장 매체의 발전으로 많은 분야에 편리함과 더불어 산업기밀유출사고의 위험이 늘어나고 있다. 보안사고 중 80% 이상이 인적 보안 유출 이였으며 현직 직원의 유출은 약 25%정도의 부분을 차지하고 있었다. 기존의 단순한 시스템 로그 정보를 이용한 사용자 감사기술, DRM을 이용한 데이터 보호기술방법 보다는 진보된 방법이 필요하다. 사용자 정보와 시스템 정보, 시스템 콜 정보 수집을 통한 구분된 감사데이터의 통계기법을 이용한 지능적인 이상행위 탐지 기법을 제시한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2007.11a
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• pp.300-303
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• 2007

사용자의 행동을 모니터링 하는 것에 대한 이전의 기술적인 연구는 네트워크 트래픽과 데이터 베이스 접근 패턴에 집중되어 있으나 이러한 접근은 사용자간의 데이터를 교환하고 공유하는 등의 상호 작용을 관찰하기에는 부족하다. 따라서 'BHave' 라는 가상 환경에서 사용자의 행동을 추적할 수 있는 시스템을 개발하여 문서에 접근하는 사용자의 행동을 모니터링한다. 서버쪽의 데이터베이스에서 데이터를 가져와서 클라이언트의 API 를 통하여 사용자가 선택한 데이터를 분석한 뒤 사용자에게 그래프를 통해서 시각적으로 분석 결과를 보여준다.

• Korean Security Journal
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• no.10
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• pp.15-34
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• 2005

1. There was significant relationship between personality traits and coping behavior. (1) Type A Group used more problem-focused and emotion-focused coping style than Type B Group (2) Non-sociable group used more emotion-focused coping style especially 'escape-avoidance' behavior than sociable group (3) Emotionally unstable group used more emotion-focused coping style especially 'distancing' and 'escape-avoidance behavior than stable group. 2. There was no significant relationship between personality traits and stress coping effect except emotional stability. 3. There was same inter-correlations among personality, coping style, and coping effect, (1) Type A was significantly correlated with sociability but not with emotional stability. (2) Problem-focused coping style was positively correlated with emotion-focused coping style. (3) Coping effect was not significantly correlated with coping style and personality traits accept emotional stability. 4. There was significant relationship between cognitive appraisal and coping style. (1) When they appraised the event 'could change or did something about it,' that used more problem-focused coping style than appraised 'had to accept.' (2) When they appraised the event ' could control before it occures.' they used more problem-focused and emotion-focused coping style than appraised it 'could not control'. (3) When they appraised the event 'had to gold back.' they used more problem-focused and emotion-focused coping style than appraised it 'had not to hold back.' (4) When they appraised the event 'happened by me.' they used more problem-focused coping style than appraised it 'happened by others.' (5) When they appraised the event 'needed to know more, 'they did not significantly use more coping behavior than appraised it 'needed not to know more.' 5. There was no significant difference except two cases in cognitive appraisal to the problem according to the personality. The two cases were as follows: (1) Sociability group appraised the event 'had to accept.' while non-sociability group appraised it 'could change or did some thing about.' (2) Emotionally stable group appraised the event 'happened by others.' while emotionally unstable group appraised it "happened by me".