• Proceedings of the Korean Information Science Society Conference
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• 2003.04a
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• pp.485-487
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• 2003

본 논문에서는 간단하고 효율적인 상호 인증 가능한 키 교환 프로토콜을 제안한다. 제안한 프로토콜은 두 참여들 사이에 미리 공유된 사람이 기억할 수 있는 패스워드를 이용하여 세션키를 교환하고 서로를 인증한다. 우리는 제안한 프로토콜이 중간 침입자 공격과 패스워드 추측 공격에 안전하고 완전한 전방향 보안성을 제공함을 보여준다. 즉, 제안한 프로토콜은 수동적인 공격자나 적극적인 공격자의 공격들에 안전하다. 제안된 프로토콜의 안정성은 이산대수 문제와 Diffie-Hellman 문제의 어려움에 기반을 두고 있다. 제안된 프로토콜은 구성이 간단하고 효율적이어서 소프트웨어나 하드웨어로 구현하기가 용이할 것으로 기대된다.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10a
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• pp.622-624
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• 2003

본 논문에서는 사람이 기억할 수 있는 패스워드만을 이용하여 안전하지 않은 통신상에서 사용자와 서버간에 서로를 인증하고 세션키를 공유하기 위한 새로운 키 교환 프로토콜을 제안한다. 제안된 프로토콜은 사용자가 자유롭게 자신의 패스워드를 변경할 수 있는 기능을 제공한다. 또한 여러 가지 다양한 공격들, 즉 패스워드 추측 공격, 중간 침입자 공격, Denning-Sacco 공격, Stolen-verifier 공격, 그리고 서비스 거부 공격에 안전하며, 완전한 전방향 보안성을 제공하도록 설계되었다.

• Proceedings of the Korean Information Science Society Conference
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• 2004.10a
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• pp.418-420
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• 2004

패스워드 기반의 키 교환 프로토콜들은 참여자들이 쉽게 기억할 수 있는 자신의 패스워드를 사용하므로 단순성, 편리성, 이동성의 장점 때문에 광범위하게 사용되지만 완전한 전 방향 보안성(perfect forward secrecy), 패스워드 추측공격과 Denning-Saccon 공격에 취약하다. 본 논문에서 제안한 검증자(verifier)를 사용한 패스워드 기반의 인증 및 키 교환 프로토콜은 키 교환 프로토콜 요구 사항을 만족하고, 알려진 공격으로부터 안전하며 DH(Diffie-Hellman) 키 교환 방법과 해쉬 함수만을 사용하기 때문에 기존의 프로토콜보다 구조가 간단하며 높은 효율성을 가진다.

• Proceedings of the Korea Multimedia Society Conference
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• 2004.05a
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• pp.131-134
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• 2004

위치기반서비스(Location Based Service)는 이동중인 사용자의 위치 정보를 타 정보와 결합해 사용자가 요청, 혹은 필요로 하는 부가적인 응용 서비스를 제공하기 위한 기술을 말한다. 현재의 개인 위주의 서비스에서 국가 전반적인 인프라 차원으로 급속히 확대 발전함에 따라 사용자의 프라이버시(Privacy) 문제나 접근제어와 같은 인증문제가 중요한 이슈로 대두되고 있다. 본 논문에서는 LBS 기업체 동향 및 전반적인 사항을 분석하여 문제점을 도출하고 LBS 프라이버시(Privacy) 보호를 위한 접근제어 문제, 인증 문제 및 키 신규성 확인 기능을 제공하는 타원곡선 기반의 인증 및 키 교환 프로토콜 기술을 제시한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2010.11a
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• pp.1320-1323
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• 2010

2009년 Yang과 Chang은 Computers and Security에 "An ID-based-remote mutual authentication with key agreement scheme on elliptic curve cryptosystem"을 제안하였다. 하지만 제안된 방법에서 사용한 타원곡선 곱셈에서 수학적 오류를 범하였고, 수학적 오류를 수정한 방법을 제안하고자 한다.

• The KIPS Transactions:PartB
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• v.8B no.5
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• pp.579-586
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• 2001

Digital watermarking is to embed imperceptible mark into image, video, audio, and text data to prevent the illegal copy of multimedia data. arbitrary modification, and also illegal sales of the copies without agreement of copyright ownership. In this paper, we study for the embedding and extraction of watermark key using wavelet in the luminance signal in order to implement the system to protect the copyright for image MPEG. First, the original image is analyzed into frequency domain by discrete wavelet transform. The RSA(Rivest, Shamir, Aldeman) public key of the coded target is RUN parameter of VLD(variable length coding). Because the high relationship among the adjacent RUN parameters effect the whole image, it prevents non-authorizer not to possess private key from behaving illegally. The Results show that the proposed method provides better moving picture and the distortion more key of insert than direct coded method on low-frequency domain based DCT.

• Geomechanics and Engineering
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• v.23 no.5
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• pp.467-480
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• 2020

The failure behavior and tensile strength of sandstone materials under different strain rates are greatly different, especially under static loads and impact loads. In order to clearly investigate the failure mechanism of sandstone materials under static and impact loads, a series of Brazilian disc samples were used by employing green sandstone, red sandstone and black sandstone to carry out static and impact loading splitting tensile tests, and the failure properties subjected to two different loading conditions were analyzed and discussed. Subsequently, the failure behavior of sandstone materials also were simulated by finite element code. The good agreement between simulation results and experimental results can obtain the following significantly conclusions: (1) The relationship of the tensile strength among sandstone materials is that green sandstone < red sandstone < black sandstone, and the variation of the tensile sensitivity of sandstone materials is that green sandstone > red sandstone > black sandstone; (2) The mainly cause for the difference of dynamic tensile strength of sandstone materials is that the strength of crystal particles in sandstone material, and the tensile strength of sandstone is proportional to the fractal dimension; (3) The dynamic failure behavior of sandstone is greatly different from that of static failure behavior, and the dynamic tensile failure rate in dynamic failure behavior is about 54.92%.

• The Journal of Society for e-Business Studies
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• v.15 no.1
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• pp.157-171
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• 2010

To effectively maintain manufacturing collaboration, the development of effective performance measurements for the collaboration is required. Most existing key performance indicators however were developed to measure the performances of internal activities or outsourcing of a company. For that reason, it is necessary to devise new key performance indicators that the partners participating in the collaboration can arrange and compromise with each other to reflect their common goals. In this paper, we propose collaborative Key Performance Indicators(cKPIs), which is used to measure the collaboration work of multiple manufacturing partners on the basis of the Supply Chain Operations Reference(SCOR) model. Also, a modified Sigmoid function is devised as a desirability function to reflect the characteristics of Service Level Agreement(SLA) between two partners. The proposed indicators and the desirability functions can be utilized to perform and maintain the successful collaboration by providing a way to the quantitative measurement.

• Korean Journal of Clinical Pharmacy
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• v.29 no.1
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• pp.18-24
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• 2019

Background: Although a growing number of guidelines and clinical researches are available for immunosuppressive treatment of post-transplantation, there is no clinical practice guideline for the care of kidney transplant recipients in Korea. Selection of a researchable question is the most important step in conducting qualified guideline development. Thus, we aimed to formulate key questions for Korean guideline to aid clinical decision-making for immunosuppressive treatment. Methods: Based on previous published guidelines review, a first survey was constructed with 29 questions in the range of immunosuppressive treatments. The experts were asked to rate the clinical importance of the question using a 5-point Likert scale. The questions reached 60% or more from the first survey and additional new questions were included in the second survey. In analyzing the responses to items rated on the 9-point scale, consensus agreement on each question was defined as 75% or more of experts rating 7 to 9. Results: In the first survey, 50 experts were included. Among the 29 questions, 27 were derived to get 60% or more importance and 3 new questions were additionally identified. Through the second survey, 9 questions were selected that experts reached consensus on 75% and over of the options. Finally, we developed key questions using PICO (patient, intervention, comparison, and outcome) methodology. Conclusion: The experts reached a high level of consensus on many of key questions in the survey. Final key questions provide direction for developing clinical practice guideline in the immunosuppressive treatment of transplantation.

• Steel and Composite Structures
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• v.31 no.1
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• pp.1-12
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• 2019

Steel-concrete composite walls have been proposed and developed for applications in various types of structures. The double-skin profiled composite walls, as a natural development of composite flooring, provide structural and architectural merits. However, adequate intermediate fasteners between profiled steel plates and concrete core are required to fully mobilize the composite action and to improve the structural behavior of the wall. In this research, two new types of fasteners (i.e., threaded rods and vertical plates) were proposed and three specimens with different fastener types or fastener arrangements were tested under axial compression. The experimental results were evaluated in terms of failure modes, axial load versus axial displacement response, strength index, ductility index, and load-strain relationship. It was found that specimen with symmetrically arranged thread rods sustained more stable axial strain than that with staggered arranged threaded rods. Meanwhile, vertical plates are more suitable for practical use since they provide stronger confinement to profiled steel plate and effectively prevent the steel plate from early local buckling, which eventually enhance the composite action and increase the axial compressive capacity of the wall. The calculation methods were then proposed and good agreement was observed between the test results and the predicted results.