• Title/Summary/Keyword: damage/damage identification

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Multi-Damage Detection in RC Bridges Using Differential Evolutionary Algorithm (차분진화 알고리즘을 이용한 다중 손상된 RC교량의 손상평가)

  • Tak, Moon-Ho;Noh, Myung-Hyun;Park, Tae-Hyo;Jang, Han-Teak
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2009.04a
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    • pp.296-299
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    • 2009
  • 본 논문은 차분진화 알고리즘을 이용한 다중 손상된 RC 슬라브 교량에 대한 시스템 인식(System Identification)기법을 소개한다. 제안된 기법을 이용하여 이동하중에 의한 교량의 동적응답을 기반으로 손상유무, 위치, 크기가 추정된다. ABAQUS를 이용한 손상된 3차원 슬라브 모델을 실험대상으로 하여, 모델로부터 동적응답을 찾아내었다. 차분진화 알고리즘(Differential Evolutioinary algorithm)을 기반으로 동적응답과 Bi-variate Gaussian 함수로 강성저하된 2차원 유한요소 MZC모델을 이용하여 손상된 위치와 크기, 이동하중의 크기와 속도가 추정되었다. 차분진화 알고리즘을 이용한 RC교량의 손상위치와 이동하중에 대한 추정은 3%이내의 오차를 보였고, 이로부터 제안된 방법의 효율성과 정확성이 검증되었다.

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Development of Damage Detection Technique in Laminated Composites using Tapping Sound (타격음을 이용한 복합재료 구조물의 손상탐지법의 개발)

  • 김승조;황준석;송준영
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2000.04a
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    • pp.171-174
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    • 2000
  • In this paper, impact sound realization of composite structures is performed to investigate the possibility of a new NDE system - Tapping Sound Analysis (TSA). TSA detects the existence of damages inside the structures by comparing tapping sound with pre-computed sound data of healthy structures. Tapping on the structures is modeled as impact problem and solved using finite element method. Calculation of sound is formulated based on the coupled finite element and boundary element method. Numerical simulation of impact sound and feature extraction scheme show that the impact sound can be used in the identification of damages of laminated composites.

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Dynamics Analysis for Preventing Failures of Steam Turbine Blade (증기터빈 블레이드의 파손방지를 위한 동특성 해석)

  • Kim, Hyo-Jin;Park, Jung-Yong
    • The KSFM Journal of Fluid Machinery
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    • v.1 no.1 s.1
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    • pp.17-23
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    • 1998
  • The blade failures are identified as the leading cause of unplanned outages for steam turbine. Most investigations of the failures are limited to material tests, chemical analysis of deposits, and possibly examination of material specimens. But to correct a blading problem requires more than positive identification of the mechanisms involved. An analytic procedure capable of predicting stress and dynamic characteristics of turbine blades is presented to increase steam turbine availability by decreasing blade failures. Finite element method is used to model and predict natural frequencies, steady and dynamic stresses of turbine blades. The procedure is illustrated by the case study. This procedure is used to guide, and support the plant manager's decision to avoid a costly, unplanned outage

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A Case of NRRL(Non-Recurrent Recurrent Laryngeal Nerve) in a Patient with the Parathyroid Adenoma (부갑상선 선종 수술시 관찰된 비회귀성 반회후두신경 (Non-Recurrent Recurrent Laryngeal Nerve) 1례)

  • 한수진;임재열;박헌이;최홍식
    • Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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    • v.11 no.2
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    • pp.188-191
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    • 2000
  • In thyroid and parathyroid surgery, damage to the recurrent laryngeal nerve(RLN) is the most common iatrogenic cause of vocal cord paralysis. Identification and preservation of the BLNs and meticulous technique can siginificantly decrease the incidence of this complication. We experienced one case of NRRLN in a patient with the parathyroid adenoma. During the dissection, there was no branch to be considered as RLN in tracheoesophageal groove. While searching for the RLN, We found a white structure coursing horizontally at the level of cricoid cartilage directly arising from the vagus nerve in the carotid sheath. That structure was nonrecurrent recurrent laryngeal nerve(NRRLN) and NRRLNs are exceedingly rare. Awareness of the possibility of NRRLN will prevent the surgeon from accidentally severing one if it is encountered during surgery.

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The Study on Improved Disaster Management System in Case of Large-scale Mass Casualties (대규모 인명피해 발생에 따른 재난관리체계 개선 방안)

  • Yoo, Byungtae;Ko, Jae Wook
    • Journal of the Korean Society of Safety
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    • v.30 no.2
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    • pp.77-82
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    • 2015
  • When accidents that relate to a large numbers of people occur, such as disasters involving group tours by ship or aircraft, or large-scale chemical leakages, it is very important to know the personal identification of victims and to determine their locations and status. It is true that there will be serious damage or injury to people who engaged especially when information does not transfer properly or people get inaccurate one. In this study, therefore, we analysed the disaster response management system for rescued people of the Sewo ferry sinking accident. Based on the analysis we proposed to improve the real-time disaster management system with ICT(Information & Communication Technology).

A Study on Severe Accident Management Capabilities and Strategies for CANDU Reactor (가압중수로형원전의 중대사고 대응능력 연구)

  • Choi, Young;Park, Jong-Ho
    • Journal of the Korean Society of Safety
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    • v.29 no.5
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    • pp.160-165
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    • 2014
  • The realistic cases causing severe core damage should be analyzed and arranged systematically for preparing an accident management of the specific nuclear power plant. The objective of this paper is to establish basic technical information for reactor safety and reactor building integrity management strategies in CANDU reactor severe accident. For the development of severe accident management strategies, plant specific features and behaviors must be studied by detailed analysis works. This analysis scope will serve to cover overall methods and analyzing results to understand the reactor building integrity status in the most likely severe accident sequences that could occur at CANDU reactor. Also analysis results could help prevent or mitigate severe accidents for the identification of any plant specific vulnerabilities to severe accidents using the probabilistic safety assessment (PSA) quantified results.

Crack propagation and deviation in bi-materials under thermo-mechanical loading

  • Chama, Mourad;Boutabout, Benali;Lousdad, Abdelkader;Bensmain, Wafa;Bouiadjra, Bel Abbes Bachir
    • Structural Engineering and Mechanics
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    • v.50 no.4
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    • pp.441-457
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    • 2014
  • This paper presents a finite element based numerical model to solve two dimensional bi-material problems. A bi-material beam consisting of two phase materials ceramic and metal is modelled by finite element method. The beam is subjected simultaneously to mechanical and thermal loadings. The main objective of this study is the analysis of crack deviation located in the brittle material near the interface. The effect of temperature gradient, the residual stresses and applied loads on crack initiation, propagation and deviation are examined and highlighted.

Investigation on cosmetology theory and prescription In Shang Han Za Bing Lun(伤寒杂病论) (『상한잡병론(伤寒杂病论)』 미용이론여방약적고찰(美容理论与方药的考察))

  • Zhu, Hui;Kim, Hyo-Chul
    • Journal of Korean Medical classics
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    • v.26 no.4
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    • pp.89-94
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    • 2013
  • Objective : To collect cosmetology text in Shang Han Za Bing Lun(伤寒杂病论), to analyze theory and prescription about cosmetology before HAN(漢) dynasty, so to allow records for modern cosmetology of Traditional Chinese Medicine. Method : Through the systematize for all terms about cosmetology, to reveal the regularity about cosmetology before HAN(漢) dynasty. Result : There were damage-appearance disease in HAN(漢) dynasty, there are lots of ideas about cosmetology in Shang Han Za Bing Lun(伤寒杂病论). Conclusion : Shang Han Za Bing Lun(伤寒杂病论) is a monograph about pattern identification and treatment, and is an important ancient book for research of cosmetology of Traditional Chinese Medicine. In the further, we will research in knowledge discovery about cosmetology of Traditional Chinese Medicine. to strengthen the guidance of the theory of Zhang Zhongjing(张仲景) for clinical practice of cosmetology of Traditional Chinese Medicine.

IDENTIFICATION OF EROSION PRONE FOREST AREA - A REMOTE SENSING AND GIS APPROACH

  • Jayakumar, S.;Lee, Jung-Bin;Enkhbaatar, Lkhagva;Heo, Joon
    • Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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    • 2008.10a
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    • pp.251-253
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    • 2008
  • Erosion and landslide cause serious damage to forest areas. As a consequence, partial or complete destruction of vegetation occurs, which leads to many cascading problems. In this study, an attempt has been made to identify the forest areas, which are under different risk categories of erosion and landslide, in part of Eastern Ghats of Tamil Nadu. Relevantthematic maps were generated from satellite data, topographical maps, primary and secondary data and weights to each map were assigned appropriately. Weighted overlay analysis was carried out to identify the erosionprone forest areas. The result of erosion and landslide prone model reveals that 4712 ha(17%) of forest area is under high risk category and 15879 ha(58.65%) isunder medium risk category. The results of spatial modeling would be very much useful to the forest officials and conservationist to plan for effective conservation.

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Review of methodologies on network defects and vulnerability

  • Park, Won-Joo;Seo, Dong-Il;Kim, Dae-Young
    • 제어로봇시스템학회:학술대회논문집
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    • 2005.06a
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    • pp.1590-1593
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    • 2005
  • Security defects occurring within corporate networks and the Internet may be abused by internal or external malicious attackers. Such abuses cause a financial toll through expenditures on additional human resources, the impact of down-time as problems are fixed, as well as damage from divulging corporate informational assets. Hence, through the precise analysis of the possible defects in network security and the identification of risks, preventative policy should be established to ensure maximum security. This report reviews methodologies that calculate and analyze levels of network security in order to resolve these problems, and generates appropriate test steps, test methods, and test items.

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