• 대한기계학회논문집A
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• 제20권12호
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• pp.3892-3898
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• 1996

In this study, the prediction of the fatigue life as well as the extimation of the characteristics of fatigue cumulative damage on GFRP under random loading were performed. The constant amplitude tests and the ramdom loading test were carried on notched GFRP specimens with a circular hole. Random waves were generated with a micro-computer and had wide band spectra. Since it is useful that the prediction of fatigue life ot the given load sequences is based on S-N curves under constant amplitude loading, the estimation of equivalent stress is done on every random waves. The equivalent stress wasat first estimated by Miner's rule and then by the proposed model which was based on Hashin-Rotem's comulative damage theory regarding nonlinear fatigue cumulative damage behavior. The fatigue lives were predicted from each equivalent stress evaluated. And each predicted fatigue llife was compared with experimental results. The number of cycles of random loads were counted by mean-cross counting method. The reuslts showed that the fatigue life predicted by proposed model was correlated well with the experimental results in comparison with Miner's model.

• 한국구조물진단유지관리공학회 논문집
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• 제6권4호
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• pp.169-179
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• 2002

This paper presents an efficient algorithm for the estimation of damage location and severity in structure using Probabilistic Neural Network (PNN). Artificial neural network has been being used for damage assessment by many researchers, but there are still some barriers that must be overcome to improve its accuracy and efficiency. The major problems with the conventional neural network are the necessity of many training data for neural network learning and ambiguity in the relation of neural network architecture with convergence of solution. In this paper, PNN is used as a pattern classifier to overcome those problems in the conventional neural network. The basic idea of damage assessment algorithm proposed in this paper is that modal characteristics from a damaged structure are compared with the training patterns which represent the damage in specific element to determine how close it is to training patterns in terms of the probability from PNN. The training pattern that gives a maximum probability implies that the element used in producing the training pattern is considered as a damaged one. The proposed damage assessment algorithm using PNN is applied to a 2-span continuous beam model structure to verify the algorithm.

• 자원ㆍ환경경제연구
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• 제19권3호
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• pp.459-483
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• 2010

본 연구는 오염을 배출하고 있는 과점기업들이 시장 진입을 내생적으로 결정할 때 정부가 부과할 수 있는 산출세와 진입세로 구성된 이부 환경세를 설계하고 있다. 특히, 시장 산출량에 따라 비례적으로 오염의 외부성이 발생하는 경우 이부 환경세는 후생을 극대화하는 사회적 최적 수준을 달성할 수 있다는 것을 보였다. 또한 논의의 확장으로 규제 과정에서 추정오차가 존재하는 경우 이부 환경세가 사회후생과 정부조세에 미치는 영향에 대해서도 분석하고 있다. 구체적으로, 사회적 이익집단들이 각자 자신들의 이익에 따라 서로 다른 정보를 제공하는 경우 이부 환경세가 시장 산출량, 정부조세, 그리고 사회 후생에 미치는 영향을 정태적으로 비교 분석해 보았다. 결과적으로, 정부가 사회 후생의 손실분과 정부의 조세 수입 모두를 고려한다면, 오염 함수의 기울기에 대한 과대 추정뿐만 아니라 수요 함수의 기울기에 대한 과소 추정에 대해 유의해야 한다.

• 한국안전학회지
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• 제31권2호
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• pp.127-132
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• 2016

In this study, the plan to construct a disaster information categorization system that can be objectively and efficiently performed was suggested in order to perform disaster management task systematically. Recently, the damage of natural disasters is gradually growing larger and faster, increasing the economic loss. Especially, as for the domestic storm damage, the damage from strong wind was found to be greater than the damage from torrential rain. Also, strong wind was found to be inflicting a great damage on human life, property and agricultural crops, so the necessity to study damage restoration from strong wind is increasing. Nevertheless, the damage items categorized in the domestic disaster year book are often comprehensive or unclear in criteria, and thus fail to reflect items or matters due to actual disaster damage. It is difficult to aggregate damage accurately such that it does not correspond to the national compensation scope or the damage amount is calculated according to subjective judgment of the investigator in charge. As such, if the disaster information management is inadequate by not applying accurate categorization criteria from damage amount calculation, there can be an issue with fairness when paying the damage support aid. Therefore, this study suggested a categorization plan for objective and efficient execution of disaster information management task in order to resolve such issues. It is expected that quick and efficient execution would be possible in disaster information management and task procedure domestically by constructing systematic categorization system related to disaster information.

• 한국지진공학회논문집
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• 제18권1호
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• pp.19-28
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• 2014

The seismic evaluation of electric power facilities in the switchyard of nuclear power plants is currently insufficient. In order to evaluate the seismic performance of lightning arrester subjected to four types of earthquake (near- and far-fault earthquakes, NEHRP Site Class A&B and D earthquakes), seismic fragility analysis using maximum likelihood estimation is performed considering various damage states. The comparison of the seismic fragility curves for three main parts of lightning arrester that are the busing, anchor and steel frame, reveals that the failure of lightning arrester is governed by the bushing damage mode such as porcelain cracking.

• Journal of Information Technology Applications and Management
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• 제15권2호
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• pp.67-82
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• 2008

Risk that breed large size disaster is happening variously for cause at social. natural a management. Incidence and damage scale are trend that increase rapidly than past. In these circumstance, to keep operational continuity of organization, area, society, risk management action that establish systematic counter measure estimating and analyze occurrence possibility and expectation damage of risk is essential indispensable issue and the best countermeasure. Risk management action does by main purpose establish optimum disaster reduction countermeasure. To deduce various countermeasure, process that estimate and analyze occurrence possibility and expectation damage of risk is essential indispensable issue. Therefore, this paper studies process design that can presume risk occurrence frequency and damage scale through distribution of probability.

• Structural Engineering and Mechanics
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• 제24권1호
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• pp.91-105
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• 2006

In this paper, post-earthquake capacity evaluation method of reinforced concrete buildings was studied. Substructure pseudo-dynamic test and static loading test of first story column in a four-story R/C building was carried out in order to investigate the validity of the evaluation method proposed in the Damage Assessment Guideline (JBDPA 2001). In pseudo-dynamic test, different levels of damage were induced in the specimens by pre-loading, and input levels of seismic motion, at which the specimens reached to the ultimate stage, were examined. From the experimental result, no significant difference in damage levels such as residual crack width between the specimens under static and pseudo-dynamic loading was found. It is shown that the seismic capacity reduction factors ${\eta}$ can provide a reasonable estimation of post-earthquake seismic capacity of R/C buildings suffered earthquakes.

• 한국지반공학회논문집
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• 제15권5호
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• pp.57-64
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• 1999

근거리 발파에 의한 구조물 피해의 임계진동수준을 결정하기 위해 구조물의 기존 균열 변형과 지반 진동수준을 계측하였다. 구조물에 대한 발파진동의 피해를 평가하기 위해 일상적인 환경변화에 의한 기존 균열의 최대 변형량을 고려한 새로운 기준을 제시하였다. 본 실험에서 사용된 2 채의 농어촌 조적조 가옥에 대한 시험 결과를 보면, 구조물에 피해를 유발하기 위한 진동 수준은 설계 기준보다 훨씬 더 큰 수준임을 알 수 있다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.678-683
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• 2003

Ultrasonic method using SH(shear horizontal) wave has been developed to determine the surface damage in fatigued material. Fatigue damages based on propagation energy were analyzed by multiregression analysis and phase measurement in interrupted fatigue test specimen including CrMoV and 12Cr alloy steel. From the test results, as the fatigue damage increased the propagation time of the launched waves increased and amplitude of wavelet decreased. Also, analysis for the waveform modulation showed a reliable estimation, with confidence limit of 97% for 12Cr steel and 95% for CrMoV steel, respectively. Therefore, It is thought that SH ultrasonic wave technique can be applied to determine fatigue damage of in-service component nondestructively.

• Computers and Concrete
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• 제5권1호
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• pp.37-60
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• 2008

Structural health monitoring of existing infrastructure is currently an important field of research, where elaborate experimental programs and advanced analytical methods are used in identifying the current state of health of critical and important structures. The paper outlines two methods of system identification of beam-like reinforced concrete structures representing bridges, through static measurements, in a distributed damage scenario. The first one is similar to the stiffness method, re-cast and the second one to flexibility method. A least square error (LSE) based solution method is used for the estimation of flexural rigidities and damages of simply supported, cantilever and propped cantilever beam from the measured deformation values. The performance of both methods in the presence of measurement errors is demonstrated. An experiment on an un-symmetrically damaged simply supported reinforced concrete beam is used to validate the developed method. A method for damage prognosis is demonstrated using a generalized, indeterminate, propped cantilever beam.