• Title/Summary/Keyword: 손상 추정

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Reconstruction of Partially Damaged face for Improving a Face Recognition Rate (얼굴 인식률 향상을 위한 손상된 얼굴 영역의 복원)

  • 최재영;황승호;김낙빈
    • Journal of Korea Multimedia Society
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    • v.7 no.3
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    • pp.308-318
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    • 2004
  • A subject to recognize the damaged facial image is becoming an important issue in commercialization of automatic face recognition. The method to recognize a face on a damaged image is divided into two types. The one is to recognize remainders after removing the damaged information and the other is to recognize a total face after recovering the damaged information. On this paper, we present the reconstruction method by analyzing the main materials after extracting the damaged region through Kohonen network. The suggested algorithm in this paper estimates feature vectors of the damaged region using eigen-faces in PCA and then reconstructs the damaged image. This allows also the reconstruction under the untrained images. Through testing the artificial images where the eye and the mouth which have many effects to face recognition are damaged, the recognition rate of the proposed results showed similar results with the method which used Kohonen network, and improved about 11.8% more than symmetrical property method. Also, in case of the untrained image, our results improved about 14% more than that of the Kohonen method and about 7% more than that of the symmetrical property method.

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Efficient Structral Safety Monitoring of Large Structures Using Substructural Identification (부분구조추정법을 이용한 대형구조물의 효율적인 구조안전도 모니터링)

  • 윤정방;이형진
    • Journal of the Earthquake Engineering Society of Korea
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    • v.1 no.2
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    • pp.1-15
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    • 1997
  • This paper presents substructural identification methods for the assessment of local damages in complex and large structural systems. For this purpose, an auto-regressive and moving average with stochastic input (ARMAX) model is derived for a substructure to process the measurement data impaired by noises. Using the substructural methods, the number of unknown parameters for each identification can be significantly reduced, hence the convergence and accuracy of estimation can be improved. Secondly, the damage index is defined as the ratio of the current stiffness to the baseline value at each element for the damage assessment. The indirect estimation method was performed using the estimated results from the identification of the system matrices from the substructural identification. To demonstrate the proposed techniques, several simulation and experimental example analyses are carried out for structural models of a 2-span truss structure, a 3-span continuous beam model and 3-story building model. The results indicate that the present substructural identification method and damage estimation methods are effective and efficient for local damage estimation of complex structures.

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Damage Detection for Bridge Pier System Using filbert-Huang Transom Technique (Hilbert-Huang변환을 이용한 교각시스템의 손상위치 추정기법)

  • 윤정방;심성한;장신애
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 2002.03a
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    • pp.159-168
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    • 2002
  • A recently developed filbert-Huang transform (HHT) technique is applied to detect damage locations of bridge structures. The HHT may be used to identify the locations of damages which exhibit nonlinear and nonstationary behavior, since the HHT can show the instantaneous frequency characteristics of the signal. A series of numerical simulations were conducted for bridge pier systems with damages under a controlled load with sweeping frequency. The results of the numerical simulation study indicate that the HHT method can reasonably identify damage locations using a limited number of acceleration sensors under severe measurement noise condition.

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모달 변형에너지를 이용한 플로팅 구조물의 손상탐지

  • Park, Su-Yong;Jeon, Yong-Hwan
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2011.06a
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    • pp.189-191
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    • 2011
  • 구조물의 동적특성인 모드형상을 통해 국부적인 손상을 탐지하는 손상평가 기법은 많은 연구자에 의해 발전되고 있다. 하지만 플로팅 구조물에 대한 손상탐지 기법은 그 사례를 찾아보기 힘들다. 본 논문에서는 플로팅 구조물의 함체 부분을 모델링 하고, 손상 전과 손상 후 구조물의 모드형상에서 얻을 수 있는 모달 변위로 나타낸 손상지수를 통해 플로팅 구조물에 발생할 수 있는 손상을 추정하여, 제안된 이론의 적용성을 검증 하였다.

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Occupational Injuries in Korea : A Comparison of Blue-Collar and White-Collar Worker's Rates and Underreporting (특집 - 제2회 산업보건학술제 수상 논문 - 한국의 산업재해 : 사무직과 생산직 근로자의 손상률 비교와 낮은 산재 보고율 -)

  • Won, Jong-Uk
    • 월간산업보건
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    • s.260
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    • pp.69-81
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    • 2009
  • $\bullet$ 목적 본 연구는 한국의 생산직 근로자와 사무직 근로자의 직업성 손상 및 질환의 차이를 비교하고 산재보고 축소(underreporting)의 규모를 추정하고자 수행되었다. $\bullet$ 방법 한국의 경인지역에서 구축된 근로자 건강진단 수진자 코호트와 1999-2001년 사이에 재직 중이었던 근로자의 건강보험 청구자료를 이용하였다. 근로자의 직무내용과 건강진단의 종류(특수건강진단 및 일반건강진단)로 사무직과 생산직 근로자로 구분하였으며, 이들 사이의 근골격계질환과 손상 및 중독에 해당하는 건강보험 이용률의 차이를 신고되지 않은 산재로 추정하였다. 이를 바탕으로 도수율, 산재발생률 및 재해율을 계산하였다. $\bullet$ 결과 생산직 근로자는 사무직 근로자보다 100 인년 당 3.47건 더 높은 건강보험이용률을 보였다. 이를 토대로 추정한 한국의 도수율은 12.57-18.1, 재해율은 2.74-3.29, 산재발생률은 3.62-5.44이었다. $\bullet$ 결론 한국 제조업의 산재발생률은 공식적인 통계보다 2-3배 더 높을 것으로 추정되지만, 연구의 제한점을 고려하여 이해할 필요가 있다.

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Structural Damage and Residual Strength of Ships in Grounding with a Forward Speed (전진형 좌초시 선박의 구조손상 및 잔류강도)

  • J.K. Paik;T.K. Lee
    • Journal of the Society of Naval Architects of Korea
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    • v.32 no.4
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    • pp.73-86
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    • 1995
  • In this paper, the mechanics of ships in grounding with a forward speed is analyzed. A raking damage estimate model in grounding of ships is proposed. The accuracy and applicability of the model are verified by a comparison of experimental results. The progressive collapse analysis of damaged gull sections under vertical bending moments is described by using the ALPS/ISUM computer code. The procedure is applied to grounding simulation of a double hull tanker with a transverseless system.

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Nondestructive Damage Identification in a Truss Structure Using Time Domain Responses (시간영역의 응답을 사용한 트러스 구조물의 비파괴 손상평가)

  • Choi, Sang-Hyun;Park, Soo-Yong
    • Journal of the Earthquake Engineering Society of Korea
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    • v.7 no.4
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    • pp.89-95
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    • 2003
  • In this paper, an algorithm to locate and size damage in a complex truss structure using the time domain response is presented. Sampled response data for specific time interval is spatially expanded over the structure to obtain the mean train energy for each element of the structure. The mean strain energy for each element is, in turn, used to build a damage index that represents the ratio of the stiffness parameter of the pre-damaged to the post-damaged structure. The validity of the methodology is demonstrated using data from a numerical example of a space truss structure with simulated damage. Also in the example, the effects of noisy data on the proposed algorithm are examined by adding random noised to the response data.

Damage Detection of Structures using Peak and Zero of Frequency Response Functions (주파수 응답함수의 피크와 제로를 이용한 구조물의 손상탐지)

  • Park, Soo-Yong
    • Journal of the Earthquake Engineering Society of Korea
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    • v.11 no.2 s.54
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    • pp.69-79
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    • 2007
  • In this paper, a technique to detect structural damage and estimate its severity using peaks and zeros of frequency response functions (FRFs) is developed. The peaks in FRFs represent the natural frequencies of the structure and the zeros provide additional information. The characteristics of peaks and zeros are defined and the calculation procedure to obtain the peaks and zeros from the relationship between frequency response function and stiffness and mass matrices are clearly explained. A structural system identification theory which is utilizing the sensitivity of stiffness of a structural member to eigenvalues, i.e., peaks and zeros, is established. The proposed method can identify damage location and its severity, with natural and zero frequencies, by estimating structural stiffness of the structure in the process of making a analytical model The accuracy and feasibility is demonstrated by numerical models of a spring-mass system and a beam structure.

Damage Identification in Truss Bridges using Damage Index Method (손상지수법을 이용한 트러스 교량의 손상추정)

  • Lee, Bong Hak;Kim, Jeong Tae;Chang, Dong Il
    • Journal of Korean Society of Steel Construction
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    • v.10 no.2 s.35
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    • pp.279-290
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    • 1998
  • An existing Damage Index Method is verified to demonstrate its feasibility for detecting structural damage in truss bridges (1) for which modal parameters are available for a few modes of vibration and (2) for which baseline modal information is not available from its as-built state. The theory of approach to detect locations of damage and to identify baseline modal model is summarized on the basis of system identification theory and modal sensitivity theory. The feasibility of the Damage Index Method is demonstrated using a numerical example of a truss bridge with 11 subsystems of 211 members and for which only two modes of vibration were recorded for post-damaged state.

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A study on development of flood depth-damage functions focused on school buildings (학교건물에 대한 홍수 침수심별 손상함수 개발에 관한 연구)

  • Lee, Chang Hee;Kim, Sang Ho;Hwang, Shin Bum;Kim, Gil Ho
    • Journal of Korea Water Resources Association
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    • v.50 no.8
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    • pp.513-520
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    • 2017
  • In order to analyze flood damage mitigation effects, it is necessary not only to analyze inundation areas and depth through hydraulic and hydrological analysis but also to estimate flood damages. Flood damages of structure and contents of buildings are generally analyzed according to the flood depth. In this study, we developed and applied flood depth-damage functions for the school buildings based on actual damage data. In addition, the development and modification procedure of flood depth-damage functions for school buildings is presented in this paper, and the developed damage functions are verified by comparing them with the existing method. It is expected that the process of developing and applying flood depth-damage functions presented in this study can be used in the cost benefit analysis of flood damage mitigation measures.