• The Science & Technology
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• no.1 s.404
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• pp.56-60
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• 2003

세계 최고의 극비기관인 미 국가안전보장국(NSA)이 운영하는 '에셜론(Echelon)' 시스템은 국경을 넘나드는 전화통화, 팩스, 텔렉스, 전자우편은 물론 단파, 항공 및 해상주파를 포함한 무선신호 등 세계 각국에서 벌어지는 전자통신을 대부분 감청할 수 있다. 하지만 1998년 이른바 '에셜론 국제통신 감청 시스템'에 관해 이런저런 보도가 나갔을 때 미국과 유럽 당국은 이 사실을 대부분 부인했다. '에셜론'은 어떤 조직이며 어떤 일을 하는 곳인지, 유럽의회의 2000년 도청능력보고서를 통해 알아보았다.

• Information and Communications Magazine
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• v.24 no.11
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• pp.51-57
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• 2007

본 고에서는 미 국방성(DoD: Department of Defense) 커뮤니티 지원 하에 국가안전보장국 (NSA: National Security Agency)에 의해 작성된 공개키 기반구조 및 키 관리 기반구조 보안토큰 보호프로파일에서의 평가대상(TOE: Target of Evaluation) 분석을 통해 보안토큰에서의 평가대상 (TOE)에 대한 응용과 보안환경에 대하여 분석한다.

• Review of KIISC
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• v.9 no.2
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• pp.3-16
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• 1999

본 고에서는 국방부의 현대적 전쟁환경에 맞는 새로운 정보시스템을 구축하여 폭넓 은 정보교환과 효율적인 정보관리 능력을 증강하기 위하여 행정, 교육, 금융, 공안, 외교 및 물류 등의 독립적인 전용 전산망을 통합된 하나의 전산망으로 구축할 경우 다중등급보안을 처리하기 위해 미국 NSA가 주도하여 수행하고 있는 MISSI와 이에 이용되는 Fortezza 그리 고 현재 미국에서 구축중에 있는 DII의 구성에 대해 분석하였다. 본 고는 향후 정보전을 대 비한 효율적인 국방망 구축을 위한 기초자료이다.

• Review of KIISC
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• v.7 no.2
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• pp.35-54
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• 1997

본 고에서는 행정, 교육, 과학기술, 금융, 국방, 공안, 외교 및 물류 등의 전산망을 위한 통합적인 보안 해결책 및 초고속정보통신망을 위한 보안 해결책을 제시하기 위한 일환으로 미국 NSA가 주도하여 수행하고 있는 MISSI에 대하여 소개를 한다. MISSI는 다중등급 보안을 근간으로 하고 있으며 무결성, 사용자 신분확인, 부인봉쇄, 비밀성 및 가용성 등의 보안 서비스를 제공하고 있다. 이들 보안 서비스를 위하여 Firewall, Fortezza, Guard 및 안전한 컴퓨터와 같은 상용의 보안 제품을 사용할 수 있도록 하고 있다. 본 고는 국가 전산망 및 초고속정보통신망의 효과적인 보안 해결책으로써의 지침을 제공해 주리라 생각된다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.11
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• pp.902-910
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• 2013

The most representative research network in Korea, KREONET, has developed DynamicKL, an advance reservation based Network Service Agent (NSA) for user driven virtual circuit services. DynamicKL provides reservation, provisioning, release, termination, and inquiry web services for network resources by using an open standard network service interface (NSI), as well as web services for network resources by using a GUI interface. In addition, it has the RICE interface to support a protection management function per VC for virtual circuits and reservations. In this article, a protection management per VC for provisioned VCs and reservations is addressed in the DynamicKL framework, as a contribution to the VC protection management issue, which results in more manageable and reliable VC services compared to other advance reservation frameworks. An administrator can detect successful or unsuccessful VC protections in the event of a primary link failure and successful or unsuccessful VC retrievals after a primary link repair, by using RICE.

• Steel and Composite Structures
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• v.36 no.4
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• pp.399-415
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• 2020

Responses of semi-rigid frames having different degrees of semi-rigidity obtained by the nonlinear static analysis (NSA) are evaluated at specific target displacements by comparing them with those obtained by the nonlinear time-history analysis (NTHA) for scaled earthquakes. The peak ground accelerations (PGA) of the earthquakes are scaled such that the obtained peak top story displacements match with the target displacements. Three different types of earthquakes are considered, namely, far-field and near-field earthquakes with directivity and fling-step effects. In order to make the study a comprehensive one, three degrees of semi-rigidity (one fully rigid and the other two semi-rigid), and two frames having different heights are considered. An ensemble of five-time histories of ground motion is included in each type of earthquake. A large number of responses are considered in the study. They include the peak top-story displacement, maximum inter-story drift ratio, peak base shear, total number of plastic hinges, and square root of sum of the squares (SRSS) of the maximum plastic hinge rotations. Results of the study indicate that the nonlinear static analysis provides a fairly good estimate of the peak values of top-story displacements, inter-story drift ratio (for shorter frame), peak base shear and number of plastic hinges; however, the SRSS of maximum plastic hinge rotations in semi-rigid frames are considerably more in the nonlinear static analysis as compared to the nonlinear time history analysis.

• Journal of the Korean Electrochemical Society
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• v.6 no.2
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• pp.134-140
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• 2003

Stretchable Polypyrrole films(Ppy-DBSA, Ppy-mixed dopants) using functionalized doping agents dodecyl-benzensulfonic acid (DBSA) and mixed dopants{DBSA with $LIClO_4$, NSA (2-naphthalenesulfonic acid), DEHSA [di(2-ethylhexyl)sulfosuccinic acid]}, were synthesized by electrochemical method. Electrochemically prepared Polypyrrole films were stretch-oriented $(L/L_0=1.0-2.5)$ by a Bone drawing method and their electrical conductivities were measured. As the drawing ratio was increased, the electrical conductivities were increased. This results might be due to the increase in crystallinity through the incresase in draw ratio. The results of temperature dependence of electrical conductivity showed that power raw $(L/L_0=1.0-2.5)$ gave the best fit to the data for stretched Ppy-DBSA and Ppy-mixed dopants films.

• Structural Engineering and Mechanics
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• v.25 no.1
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• pp.53-73
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• 2007

In this study, an effective load increment method for multi modal adaptive non-linear static (pushover) analysis (NSA) for building type structures is presented. In the method, lumped plastisicity approach is adopted and geometrical non-linearties (second-order effects) are included. Non-linear yield conditions of column elements and geometrical non-linearity effects between successive plastic sections are linearized. Thus, load increment needed for formation of plastic sections can be determined directly (without applying iteration or step-by-step techniques) by using linearized yield conditions. After formation of each plastic section, the higher mode effects are considered by utilizing the essentials of traditional response spectrum analysis at linearized regions between plastic sections. Changing dynamic properties due to plastification in the system are used on the calculation of modal lateral loads. Thus, the effects of stiffness changes and local mechanism at the system on lateral load distribution are included. By using the proposed method, solution can be obtained effectively for multi-mode whereby the properties change due to plastifications in the system. In the study, a new procedure for determination of modal lateral loads is also proposed. In order to evaluate the proposed method, a 20 story RC frame building is analyzed and compared with Non-linear Dynamic Analysis (NDA) results and FEMA 356 Non-linear Static Analysis (NSA) procedures using fixed loads distributions (first mode, SRSS and uniform distribution) in terms of different parameters. Second-order effects on response quantities and periods are also investigated. When the NDA results are taken as reference, it is seen that proposed method yield generally better results than all FEMA 356 procedures for all investigated response quantities.

• Convergence Security Journal
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• v.18 no.3
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• pp.77-85
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• 2018

With the convergence of communications network between control system and public network, such threats like information leakage/falsification could be fully shown in control system through diverse routes. Due to the recent diversification of security issues and violation cases of new attack techniques, the security system based on the information database that simply blocks and identifies, is not good enough to cope with the new types of threat. The current control system operates its security system focusing on the outside threats to the inside, and it is insufficient to detect the security threats by insiders with　the authority of security access. Thus, this study conducted the importance analysis based on the main event log list of "Spotting the Adversary with Windows Event Log Monitoring" announced by NSA. In the results, the matter of importance of event log for the detection of insider threats to control system was understood, and the results of this study could be contributing to researches in this area.

• Structural Engineering and Mechanics
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• v.83 no.3
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• pp.327-340
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• 2022

The Collapse Margin Ratio (CMR) is a notable index used for seismic assessment of the structures. As proposed by FEMA P695, a set of analyses including the Nonlinear Static Analysis (NSA), Incremental Dynamic Analysis (IDA), together with Fragility Analysis, which are typically time-taking and computationally unaffordable, need to be conducted, so that the CMR could be obtained. To address this issue and to achieve a quick and efficient method to estimate the CMR, the Artificial Neural Network (ANN), Response Surface Method (RSM), and Adaptive Neuro-Fuzzy Inference System (ANFIS) will be introduced in the current research. Accordingly, using the NSA results, an attempt was made to find a fast and efficient approach to derive the CMR. To this end, 5016 IDA analyses based on FEMA P695 methodology on 114 various Reinforced Concrete (RC) frames with 1 to 12 stories have been carried out. In this respect, five parameters have been used as the independent and desired inputs of the systems. On the other hand, the CMR is regarded as the output of the systems. Accordingly, a double hidden layer neural network with Levenberg-Marquardt training and learning algorithm was taken into account. Moreover, in the RSM approach, the quadratic system incorporating 20 parameters was implemented. Correspondingly, the Analysis of Variance (ANOVA) has been employed to discuss the results taken from the developed model. Additionally, the essential parameters and interactions are extracted, and input parameters are sorted according to their importance. Moreover, the ANFIS using Takagi-Sugeno fuzzy system was employed. Finally, all methods were compared, and the effective parameters and associated relationships were extracted. In contrast to the other approaches, the ANFIS provided the best efficiency and high accuracy with the minimum desired errors. Comparatively, it was obtained that the ANN method is more effective than the RSM and has a higher regression coefficient and lower statistical errors.