• 정보처리학회논문지C
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• 제9C권2호
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• pp.157-162
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• 2002

본 연구에서는 DES 알고리즘과 EDE 알고리즘을 이용한 데이터 암호화와 전자서명 기술을 접목한 인터넷 폰 보안 시스템을 구현하였다. 비밀키 알고리즘의 키 분배 문제를 해결하기 위하여 Diffie-Hellman 알고리즘을 이용한 새로운 키 분배 방법을 제안하였다. 그리고 암호화에 따른 전송지연 시간을 감소시키기 위해 DES 알고리즘의 S-Box와 P-Box를 하나의 테이블로 조합하여 운영하였다. 제안된 인터넷 폰 보안 시스템은 자바로 구현하였으며, 실험결과 DES 알고리즘을 이용할 경우 1.46초, EDE 알고리즘을 이용할 경우 3.25초의 전송지연 시간을 보였다 제안된 시스템에서 사용된 기술들은 향후 음향제작물의 저작권 보호와 인터넷을 이용하는 데이터의 보호에 적용할 수 있을 것으로 생각된다.

• 정보보호학회논문지
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• 제7권3호
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• pp.65-78
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• 1997

DES가 Differential Cryptanalysis(이하 DC)에 쉽게 공격받을 수 있는 결정적인 취약점은 5-box를 포함한 암호함수의 구조에 있다 따라서 DES의 DC에 대한 대응방안으로는 XOR분포가 완전하게 균일(입력 XOR가 zero일 경우는 제외)하도록 5-box를 재구성하는 방법과 N-1 라운드 특성이 구성될 확률을 낮추기 위해 DES 알고리즘의 일부를 수정하는 방법을 생각할 수 있다. 그러나 Dawson과 Tavares가 제안한 완전히 균일한 XOR분포 테이블을 갖는 S-box는 오히려 균일하지 않을 매보다 더 취약하다고 Pieprzyk의 연구결과에 의해 증명되었다 결국 DES가 DC에 대응하기 위해서는 5-box의 재설계만으로는 부족하며 암호함수 자체를 수정해야 할 것이다. 본 논문에서는 DES의 암호함수를 일부 수정하여 DC에 대한 반복 특성이 구성될 확률을 낮추는 방안을 제안하고자 한다. 비교 분석 결과 제안된 알고리즘이 기존의 DES보다 DC 공격에 강함을 확인하였다.

• 정보보호학회논문지
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• 제21권2호
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• pp.91-100
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• 2011

Triple DES(Data Encryption Standard)는 DES의 안전성을 향상시키기 위하여 2번의 DES 암호화와 1번의 DES 복호화를 수행하는 국제 표준 암호 알고리즘이다. 본 논문에서는 Triple DES에서 수행되는 각각의 DES 알고리즘 중 마지막 라운드를 실행시키지 않도록 오류를 주입함으로써 비밀키를 찾아내는 차분 오류 분석(Differential Fault Analysis, DFA)공격을 제안한다. 제안한 공격 방법을 이용하여 시뮬레이션 결과, 9개 정도의 정상-오류 암호문 쌍을 얻을 수 있으면 $2^{24}$번의 비밀 키 전탐색을 통해 3개의 비밀키를 모두 찾을 수 있었다. 또한, ATmega128 칩에 Triple DES 암호 알고리즘을 실제로 구현하고 레이저를 이용한 오류를 주입함으로써 제안 공격이 오류 주입 대응책이 적용되지 않은 범용 마이크로프로세서 칩에 적용 가능함을 검증하였다.

• Advances in Computational Design
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• 제3권4호
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• pp.405-418
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• 2018

Building Information Modelling (BIM) and Discrete Event Simulation (DES) are tools widely used in the context of the construction industry. While BIM is used to represent the physical and functional characteristics of a facility, DES models are used to represent its construction process. Integrating both is beneficial to those interested in the field of construction management since it has many potential applications. Game engines provide a human navigable 3D virtual environment in which the integrated BIM and DES models can be visualised and interacted with. This paper reports the experience obtained while developing a simulator prototype which integrates a BIM and a DES model of a single construction activity within a commercial game engine. The simulator prototype allows the user to visualise how the duration of the construction activity is affected by different input parameters interactively. It provides an environment to conduct DES studies using the user's own BIM models. This approach could increase the use of DES technologies in the context of construction management and engineering outside the research community. The presented work is the first step towards the development of a serious game for construction management education and was carried out to determine the suitable IT tools for its development.

• 한국통신학회논문지
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• 제28권10B호
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• pp.916-926
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• 2003

본 논문에서는 VoIP의 보안을 위하여 적용된 암호화와 보안 적용 방식이 실시간 통신에 미치는 영향을 알아보기 위해 암호화에 주로 사용되는 DES, 3DES, SEED, AES 등의 암호 알고리즘을 VoIP에 적용한 후 지터나 RTT, 패킷 손실률 등의 여러 가지 QoS 요소를 측정하여 보았다. 또한 각 알고리즘별 암$.$복호화 전과 후의 패킷처리 시간 간격을 측정하여 암호화로 인한 시간 간격의 변화를 알아보았고, 음성으로 재생되기 직전의 처리 시간 간격을 측정하여 각 패킷이 어느 정도 주기적으로 공급되는지 여부와 실제 음질을 비교하여 보았다. 또한 대표적인 실시간 멀티미디어 보안 프로토콜인 H.235와 SRTP에서의 RTP 보안 적용 방식을 비교하여 키 교환 및 보안성과 공격 방어 측면 그리고 RTP 보안 적용의 효율성 등을 분석하였다.

• Steel and Composite Structures
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• 제45권6호
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• pp.839-850
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• 2022

This paper presents an analytical solution to study the combined effect of non-local and stretching effect on the vibration of advanced functionally graded (FG) nanoplates. A new quasi-3D plate theory is presented; there are only five unknowns and any shear correction factor is used. A new displacement field with a new shear warping function is proposed. The equilibrium equations of the FG nanoplates are obtained using the Hamilton principle and solved numerically using the Navier technique. The material properties of functionally graded nanoplates are presumed to change according to the power-law distribution of ceramic and metal constituents. The numerical results of this work are compared with those of other published results to indicate the accuracy and convergence of this theory. Hence, a profound parameterstudy is also performed to show the influence of many parameters of the functionally graded nanoplates on the free vibration responses is investigated.

• 정보보호학회논문지
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• 제9권1호
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• pp.3-14
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• 1999

본 논문에서는 스마트 카드를 이용한 인터넷 환경에서의 클라이언트-서버 인증 시스템을 설계, 구현하였다. 대칭형 암호인 삼중 DES를 지원하는 GEMPLUS사의 MPCOS-3DES 스마트 카드를 통해서 시도-응답(Challenge-Response) 기반의 사용자-카드, 플라이언트-서버 그리고 카드와 서버간의 3단계 인증 과정이 수행되어 진다.

• The Plant Pathology Journal
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• 제15권3호
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• pp.137-143
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• 1999

A novel chromosomal gene tagging technique using a specific fragment of the fatty acid desaturase-like open reading frame (des-like ORF) from the tox-argK gene cluster of Pseudomonas syringae pv. phaseolicola was developed to identify Xanthomonas spp.released into the environment as biocontrol agents. X. campestris pv. convolvuli FB-635, a pathogen of Convolvulus arvensis L., (bindweed), was chosen as the organism in which to develop and test the system. A 0.52 kb DES fragment amplified from P. syringae pv. phaseolicola C-199 was inserted into pGX15, a cosmid clone containing a 10.3 kb Eco RI-HindIII fragment derived from the xanthomonadin biosynthetic gene cluster contained in plasmid pIG102, to create a pigG::DES insertion. The 10.8 kb EcoRI-BamHI fragment carrying the pigG:: DES insertion was cloned into pLAFR3 to generate pLXP22. pLXP22 was then conjugated into X. campestris pv. convolvuli FB-635 and the pigG::DES insertion integrated into the bacterial chromosome by marker exchange. Rifampicin resistant, tetracycline sensitive, starch hydrolyzing, white colonies were used to differentiate the marked strain from yellow pigmented wild-type ones. PCR primers specific for the unique DES fragment were used for direct detection of the marked strain. Result showed the marked strain could be detected at very low levels even in the presence of high levels of other closely related or competitive bacteria. This PCR-based DES-tagging system provides a rapid and specific tool for directly monitoring the dispersal and persistence of Xanthomonas spp.released into the environment.

• Journal of Preventive Medicine and Public Health
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• 제46권4호
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• pp.201-209
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• 2013

Objectives: The goal of this study was to perform an economic analysis of a primary stenting with drug-eluting stents (DES) compared with bare-metal stents (BMS) in patients with acute myocardial infarction (AMI) admitted through an emergency room (ER) visit in Korea using population-based data. Methods: We employed a cost-minimization method using a decision analytic model with a two-year time period. Model probabilities and costs were obtained from a published systematic review and population-based data from which a retrospective database analysis of the national reimbursement database of Health Insurance Review and Assessment covering 2006 through 2010 was performed. Uncertainty was evaluated using one-way sensitivity analyses and probabilistic sensitivity analyses. Results: Among 513 979 cases with AMI during 2007 and 2008, 24 742 cases underwent stenting procedures and 20 320 patients admitted through an ER visit with primary stenting were identified in the base model. The transition probabilities of DES-to-DES, DES-to-BMS, DES-to-coronary artery bypass graft, and DES-to-balloon were 59.7%, 0.6%, 4.3%, and 35.3%, respectively, among these patients. The average two-year costs of DES and BMS in 2011 Korean won were 11 065 528 won/person and 9 647 647 won/person, respectively. DES resulted in higher costs than BMS by 1 417 882 won/person. The model was highly sensitive to the probability and costs of having no revascularization. Conclusions: Primary stenting with BMS for AMI with an ER visit was shown to be a cost-saving procedure compared with DES in Korea. Caution is needed when applying this finding to patients with a higher level of severity in health status.

• Membrane and Water Treatment
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• 제11권2호
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• pp.123-130
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• 2020

Submerged Membrane bioreactor (SMBR) is one of the last techniques that allow a high quality of treated industrial effluents by coupling biological treatment and membrane separation. Thus, this research was an effort to evaluate performance of a SMBR treating a model textile wastewater (MTWW). Different SMBR operating parameters like mixed liquor suspended solids (MLSS) and Dissolved oxygen concentration, hydraulic retention time (HRT), and nutrients addition (N and P) have been investigated. MTWW (influent to the SMBR) was generated using the reactive azo-dye, Novacron blue FNG (100mg/L feed concentration). Results of MTWW treatment using SMBR under optimal operating conditions (MLSS, 4.2-13.3g/L; HRT, 4 days; pH, 6.9-7.2; conductivity, 400-900 μS/cm and temperature, 19.4-22.2 ℃) showed that COD and blue colour treatment performances are between 94-98% and 30-80%, respectively. It is concluded that SMBR can be used in large scale textile wastewater treatment plants to improve effluent quality in order to meet effluent discharge standards.