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  • Title/Summary/Keyword: 손상코드

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Structural Analysis for the Container-Shaped Type A Package of Radioactive Materials (컨테이너형태의 방사성물질 A형 운반용기에 대한 구조해석)

  • 이영신;이호철;정성환;이흥영;김용재
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.14 no.2
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    • pp.143-150
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    • 2001
  • 원자력발전소의 1차 계통에서 오염된 장비들을 취급이 용이하고 안전하게 운반하기 위한 운반용기는 내부의 방사성 물질에 대한 방사능 평가에 의하여 방사성물질 A형 운반용기로 분류된다. 방사성물질 A형 운반용기는 IAEA Safety Standard Series No. ST-1 및 국내 원자력법 등 관련규정의 기술기준을 만족하여야 하는데, 운반용기는 중량에 따라 0.3∼1.2m의 높이에서 소성이 일어나지 않는 단단한 바닥면으로 가장 심각한 손상을 주는 방향으로 낙하시키는 정상운반조건(normal transport conditions)에 대하여 구조적 건전성을 유지하여야 한다. 여기서는 ABAQUS/Explicit 코드를 이용하여 컨테이너형태의 A형 운반용기에 대하여 최대손상이 야기되는 0.9m 경사낙하조건에 대한 3차원 충격해석을 수행하고 구조적 건전성을 평가하였는데, 운반용기는 경사낙하시 코너피팅(corner fitting)의 분쇄(crush)에 의하여 대부분의 충격을 흡수하였으며 운반용기의 격납경계는 구조적 건전성을 유지하였다.

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차세대원자로의 주증기관 파단사고시 안전주입수 직접주입에 대한 유체혼합해석

  • 강형석;조봉현;배윤영
    • Proceedings of the Korean Nuclear Society Conference
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    • 1996.05b
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    • pp.304-309
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    • 1996
  • 차세대원자로(KNGR) 안전주입계통은 원자로용기 하향유로(RVDC)로 직접주입(DVI)되도록 설계되며 이는 4-트레인 안전주입계통의 설계에 있어 고유한 기본구조이다. DIV 채택으로 인해 가압열충격(PTS)과 관련된 인허가 상의 관심사론 조사하고 DVI 주입구 위치에 대한 RVDC에서의 유체거동과 온도분포를 상용전산코드인 FLOW3D를 이용하여 분석하였다. PTS관점에서 가장 최악의 경우인 외부 전원상실을 동반한 영출력 주증기관 파단사고를 해석대상으로 하였으며 사고후 570 ~ 600초 사이의 과도상태를 분석하였다. 본 연구의 결과로 주증기관 파단으로 야기되는 자연순환에 의한 열혼합은 충분히 이루어져 RVDC에서의 온도가 R TPTS 이상임을 확인했고 손상루프측 위의 DVI 주입구의 유동중 일부가 손상루프측 저온관 유동과 상호작용하여 건전루프측 저온관아래로 흐르며 이 영향으로 건전루프측 저온관 아래에서의 온도가 국부적으로 감소함을 확인하였다.다.

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Challenges of Address Sanitizer in Embedded Systems (임베디드 시스템에서 Address Sanitizer 의 한계)

  • Jaeyeol Park;Seonghwan Park;Donghyun Kwon
    • Annual Conference of KIPS
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    • 2023.05a
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    • pp.156-157
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    • 2023
  • 메모리 손상으로 인해 발생하는 컴퓨터 시스템의 버그는 아주 오랫동안 지속적으로 발견된 컴퓨터 보안 이슈 중 하나이다. 이에 대한 보호 기법이 많이 제안되었으며 Address Sanitizer(ASAN) 또한 buffer overflow, use-after-free 와 같은 메모리 손상 버그를 보호하기 위한 기술 중 하나이다. 그러나 해당 기술은 소프트웨어적으로만 구현되었고, 충분한 컴퓨팅 자원이 있을 때만 그 유효성과 실용성이 검증되었고 컴퓨팅 자원이 제한된 임베디드 시스템에서의 적용에 대한 연구나 실효성 검증이 부족하다. 이에 본 논문에서는 임베디드 시스템에 ASAN 를 적용하기 위한 코드를 작성하고 성능을 측정하고 분석하였다.

Development of Non-Contact Fiber Jumper Cord and Evaluation of Light Transmission Performance (비접촉식 광 점퍼 코드 개발 및 광 전송 성능 평가)

  • Kim, Heonyoung;Kang, Donghoon
    • Journal of the Korean Society for Nondestructive Testing
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    • v.36 no.5
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    • pp.399-405
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    • 2016
  • Recently, fiber optic sensors, which have many advantages are being applied in various fields by replacing conventional electric sensors. To transmit the light signals between an interrogator and a sensor head, optical components such as an optical adaptor and optical jumper cords are generally used. When signals are transmitted using an adaptor, the end surface of each jumper cord is faced together. If alien substances exist on the core surface of an optical fiber, those can cause light transmission loss and signal disappearance. For this reason, non-contact fiber jumper cords are developed to overcome the problems that require continual attention. The light transmission performance of non-contact fiber jumper cords are also evaluated. From the test results, conventional fiber jumper cords are unable to transmit the signals over 2 mm cavity between the ends of both cords. Otherwise, non-contact fiber jumper cords can transmit the signals with stability up to the cavity of 7 mm though they have more transmission loss than the conventional ones. Consequently, non-contact fiber jumper cords that have better signal stability than conventional ones in environments are highly recommended in field applications, especially if they play a role as a cable for signal transmission between fiber optic sensors.

Study on the Precise Controlling of Fracture Plane in Smooth Blasting Method (SB발파에서 파단면 제어의 고도화에 관한 연구)

  • Cho, Sang-Ho;Jeong, Yun-Young;Kim, Kwang-Yum;Kaneko, Katsuhiko
    • Tunnel and Underground Space
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    • v.19 no.4
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    • pp.366-372
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    • 2009
  • Recently, in order to achieve smooth fracture plane and minimize the excavation damage zone in rock blasting, controlled blasting methods which utilize new technologies such as electronic delay detonator (EDD) and a notched charge hole have been suggested. In this study, smooth blastings utilizing three wing type notched charge holes are simulated to investigate the influence of explosive initial density on the resultant fracture plane and damage zone using dynamic fracture process analysis (DFPA) code. Finally, based on the dynamic fracture process analyses, novel smooth blasting method, ED-Notch SB (Electronic Detonator Notched Charge Hole Smooth Blasting) is suggested.

LSTF 주증기배관 파단사고 평가

  • 이규복;손상배
    • Proceedings of the Korean Nuclear Society Conference
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    • 1996.05b
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    • pp.260-267
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    • 1996
  • LSTF의 주증기배관 파단사고 실험(RUN SB-SL-01)에 대한 RELAP5/MOD2 해석결과를 제시하고, LSTF의 RUN SB-SL-01 실험결과 중에서 일차측과 이차측 사이의 열전달률에 촛점을 맞추어 증기발생기 이차측 및 일차계통의 압력, 온도 등과 같은 주요변수를 조사하여 RELAP5/MOD2코드의 성능을 평가하였다. 10% 주증기배관파단사고에 관한 최적 평가에서 주요 매개변수의 전체적 추세가 비교적 잘 예측되었다. 원자로압력용기 상층부에서 기포가 발생하는 기간 동안에는 계통 압력에서 작은 차이가 발생함을 알 수 있었는데, 압력차 발생은 가압기가 비어 있거나 원자로압력용기 상층부에서 기포가 발생하기 때문으로 판단된다.

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Study on Design Change of a Pipe Affected by Liquid Droplet Impingement Erosion (액적충돌침식 영향 배관의 설계변경에 관한 연구)

  • Hwang, Kyeong-Mo;Lee, Chan-Gyu;Bhang, Keug-Jin;Yim, Young-Sig
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.35 no.10
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    • pp.1097-1103
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    • 2011
  • Liquid droplet impingement erosion (LDIE) is caused by the impact of high-velocity droplets entrained in steam or air on metal. The degradation caused by the LDIE has been experienced in steam turbine internals and high-velocity airplane components (particularly canopies). Recently, LDIE has also been observed in the pipelines of nuclear plants. LDIE among the pipelines occurs when two-phase steam experiences a high pressure drop (e.g., across an orifice in a line to the condenser). In 2011, a nuclear power plant in Korea experienced a steam leak caused by LDIE in a pipe through which a two-phase fluid was flowing. This paper describes a study on the design change of a pipe affected by LDIE in order to mitigate the damage. The design change has been reviewed in terms of fluid dynamics by using the FLUENT code.

Block-based Image Authentication Algorithm using Differential Histogram-based Reversible Watermarking (차이값 히스토그램 기반 가역 워터마킹을 이용한 블록 단위 영상 인증 알고리즘)

  • Yeo, Dong-Gyu;Lee, Hae-Yeoun
    • The KIPS Transactions:PartB
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    • v.18B no.6
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    • pp.355-364
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    • 2011
  • In most applications requiring high-confidential images, reversible watermarking is an effective way to ensure the integrity of images. Many watermarking researches which have been adapted to authenticate contents cannot recover the original image after authentication. However, reversible watermarking inserts the watermark signal into digital contents in such a way that the original contents can be restored without any quality loss while preserving visual quality. To detect malicious tampering, this paper presents a new block-based image authentication algorithm using differential histogram-based reversible watermarking. To generate an authentication code, the DCT-based authentication feature from each image block is extracted and combined with user-specific code. Then, the authentication code is embedded into image itself with reversible watermarking. The image can be authenticated by comparing the extracted code and the newly generated code and restored into the original image. Through experiments using multiple images, we prove that the presented algorithm has achieved over 97% authentication rate with high visual quality and complete reversibility.

Ransomware Detection and Recovery System Based on Cloud Storage through File System Monitoring (파일 시스템 모니터링을 통한 클라우드 스토리지 기반 랜섬웨어 탐지 및 복구 시스템)

  • Kim, Juhwan;Choi, Min-Jun;Yun, Joobeom
    • Journal of the Korea Institute of Information Security & Cryptology
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    • v.28 no.2
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    • pp.357-367
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    • 2018
  • As information technology of modern society develops, various malicious codes with the purpose of seizing or destroying important system information are developing together. Among them, ransomware is a typical malicious code that prevents access to user's resources. Although researches on detecting ransomware performing encryption have been conducted a lot in recent years, no additional methods have been proposed to recover damaged files after an attack. Also, because the similarity comparison technique was used without considering the repeated encryption, it is highly likely to be recognized as a normal behavior. Therefore, this paper implements a filter driver to control the file system and performs a similarity comparison method that is verified based on the analysis of the encryption pattern of the ransomware. We propose a system to detect the malicious process of the accessed process and recover the damaged file based on the cloud storage.

Crashworthy Safety Assessment of High Speed Passenger Ship with Underwater Floating Matter (쾌속여객선의 수중부유물과의 내충돌 안전성 평가)

  • Lee, Sang-Gab;Lee, Jae-Seok;Baek, Yun-Hwa;Jun, Seung-Hwan
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2009.06a
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    • pp.30-31
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    • 2009
  • Through the full scale ship collision response analysis of high speed passenger ship with underwater floating matters, the objective of this study is to perform the crashworthy safety assessment of its hull and passengers. For this safety assessment, diverse collision scenarios could be established through the thorough understanding of damage mechanisms due to the collision of its hydrofoil system with underwater floating matter examining the damage informations of its hull and passengers from the collision accidents, and through the estimation of the damages of its hull and passenger. The next step, crashworthy safety assessment of its hull and passengers, was carried out by the collision response analyses of high speed passenger ship with underwater floating matter using Fluid-Structure Interaction(FSI) analysis technique of LS-DYNA code in consideration of surrounding water, and using local zooming analysis technique.

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