• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.3
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• pp.529-540
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• 2015

The NGN should support an ubiquitous environment in which users can use multiple devices. Especially, services should be provided to users in a seamless manner across multiple devices which are dynamically found in users' vicinity. Therefore, supporting service continuity is essential in the NGN. Currently the IMS, which is a session control layer for the NGN, deals with session control procedures in detail for service continuity. However, the IMS provides limited methods how users can find target terminals for transferring the session. The target terminals tend to be located near in user's physical location, and could be shared among different users. For providing better service experience in the NGN, The NGN needs to encompass methods to enable for users to use the dynamically-found terminals in users' vicinity seamlessly. In this paper, we introduce a novel registration method based on virtual ISIM by which the target terminals in user's vicinity can register themselves to the IMS, and also we discuss how service continuity is supported.

• Current Industrial and Technological Trends in Aerospace
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• v.6 no.2
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• pp.80-89
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• 2008

Photogrammetry is a non-direct 3-dimensional coordinate measurement technique using 2-dimensional photographic images. For reconstruction 3-dimensional data from the 2-dimensional photos, photogrammetry uses the fundamental principle of triangulation. Digital photogrammetry solve for the camera location and coordinates simultaneously through the mapping, scaling and bundle processing in software processing. In this paper, several applications for photogrammetry measurement are introduced, such as 'photogrammetric measurement of the gravity deformation of a cassegrain type antenna', 'analysis of photogrammetry data from ISIM mockup', 'underwater photogrammetric verification of nuclear fuel assemblies', 'spacecraft optical bench measurement' and 'spacecraft ground support equipment measurement'.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.05a
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• pp.169-170
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• 2018

이진체 상의 타원곡선 B-233을 지원하는 타원곡선 암호 프로세서를 32-비트 워드기반 몽고메리 곱셈기를 이용하여 설계하였다. 스칼라 곱셈을 위해 수정된 몽고메리 래더 (Modified montgomery ladder) 알고리즘을 적용하여 단순 전력분석에 내성을 갖도록 하였으며, Lopez-Dahab 투영 좌표계와 페르마의 소정리(Fermat's little theorem)를 적용하여 하드웨어 자원 소모가 큰 나눗셈과 역원 연산을 제거하여 저면적으로 설계하였다. 설계된 ECC 프로세서는 Xilinx ISim을 이용하여 기능검증을 하였으며, $0.18{\mu}m$ CMOS 셀 라이브러리로 합성한 결과 100 MHz의 동작 주파수에서 9,614 GEs와 4 Kbit RAM으로 구현되었으며, 최대 동작 주파수는 125 MHz로 예측되었다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.05a
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• pp.188-190
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• 2017

투영(projective) 좌표계를 이용한 스칼라 곱셈(scalar multiplication) 연산을 지원하는 224-비트 타원곡선 암호(Elliptic Curve Cryptography; ECC) 프로세서의 설계에 대해 기술한다. 소수체 GF(p)상의 덧셈, 뺄셈, 곱셈 등의 유한체 연산을 지원하며, 연산량과 하드웨어 자원소모가 큰 나눗셈 연산을 제거함으로써 하드웨어 복잡도를 감소시켰다. 수정된 Montgomery ladder 알고리듬을 이용하여 스칼라 곱셈 연산을 제어하였으며, 단순 전력분석에 보다 안전하다. 스칼라 곱셈 연산은 최대 2,615,201 클록 사이클이 소요된다. 설계된 ECC-P224 프로세서는 Xilinx ISim을 이용한 기능검증을 하였다. Xilinx Virtex5 FPGA 디바이스 합성결과 7,078 슬라이스로 구현되었으며, 최대 79 MHz에서 동작하였다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.05a
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• pp.194-196
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• 2017

본 설계에서는 임의의 길이의 메시지를 256-비트의 해시 코드로 압축하는 해시 알고리듬인 SHA-256(Secure Hash Algorithm-256) 해시함수를 경량화 구현 설계 하였다. 미국 표준 기술연구소 NIST에서 발표한 표준문서 FIPS 180-4에 정의16된 32-비트의 데이터 패스를 16-비트로 설계하여 경량화 구현하였다. Verilog HDL로 설계된 SHA-256 해시함수는 Xilinx ISim를 사용하여 시뮬레이션 검증을 하였다. CMOS 표준 셀 라이브러리로 합성한 결과 100MHz 동작주파수에서 18,192 GE로 구현되었으며, 192MHz의 최대 동작주파수를 갖는다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.10a
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• pp.158-160
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• 2016

전자서명(ECDSA), 키 교환(ECDH) 등에 사용되는 233-비트 타원곡선 암호(Elliptic Curve Cryptography; ECC) 프로세서의 설계에 대해 기술한다. $GF(2^{333})$ 상의 덧셈, 곱셈, 나눗셈 등의 유한체 연산을 지원하며, 하드웨어 자원 소모가 적은 쉬프트 연산과 XOR 연산만을 이용하여 구현하였다. 스칼라 곱셈은 modified montgomery ladder 알고리듬을 이용하여 구현하였으며, 정수 k의 정보를 노출하지 않고, 단순 전력분석에 보다 안전하다. 스칼라 곱셈 연산은 최대 490,699 클록 사이클이 소요된다. 설계된 ECC 프로세서는 Xilinx ISim을 이용한 시뮬레이션 결과값과 한국인터넷진흥원(KISA)의 참조 구현 값을 비교하여 정상 동작함을 확인하였다. Xilinx Virtex5 XC5VSX95T FPGA 디바이스 합성결과 1,576 슬라이스로 구현되었으며, 189 MHz의 최대 동작주파수를 갖는다.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.31 no.1
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• pp.41-48
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• 2008

Enhanced machine reliability has dramatically reduced the rate and number of railway accidents but for further reduction human error should be considered together that accounts for about 20% of the accidents. Therefore, the objective of this study was to suggest a new taxonomy of performance shaping factors (PSFs) that could be utilized to identify the causes of a human error associated with railway accidents. Four categories of human factor, task factor, environment factor, and organization factor and 14 sub-categories of physical state, psychological state, knowledge/experience/ability, information/communication, regulation/procedure, specific character of task, infrastructure, device/MMI, working environment, external environment, education, direction/management, system/atmosphere, and welfare/opportunity along with 131 specific factors was suggested by carefully reviewing 8 representative published taxonomy of Casualty Analysis Methodology for Maritime Operations (CASMET), Cognitive Reliability and Error Analysis Method (CREAM), Human Factors Analysis and Classification System (HFACS), Integrated Safety Investigation Methodology (ISIM), Korea-Human Performance Enhancement System (K-HPES), Rail safety and Standards Board (RSSB), $TapRoot^{(R)}$, and Technique for Retrospective and Predictive Analysis of Cognitive Errors (TRACEr). Then these were applied to the case of the railway accident occurred between Komo and Kyungsan stations in 2003 for verification. Both cause decision chart and why-because tree were developed and modified to aid the analyst to find causal factors from the suggested taxonomy. The taxonomy was well suited so that eight causes were found to explain the driver's error in the accident. The taxonomy of PSFs suggested in this study could cover from latent factors to direct causes of human errors related with railway accidents with systematic categorization.