• Structural Engineering and Mechanics
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• 제9권2호
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• pp.195-208
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• 2000

To confirm the theory and static defect energy (SDE) equations proposed in the first part, extensive numerical simulation studies are performed in this portion. Stiffness method is applied to calculate the components of the stresses and strains from which the energy components and finally, the SDE are obtained. Examples are designed to cover almost all kinds of possibilities. Variables include structural type, material, cross-section, support constraint, loading type, magnitude and position. The SDE diagram is unique in the way of presenting damage information: two different energy constants are separated by a sharp vertical drop right at the damage location. Simulation results are successfully implemented for both methods in all the cases.

• 한국조경학회지
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• 제35권4호
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• pp.71-80
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• 2007

The purpose of this study is to suggest the criteria for the damaged mountainous landscape based on the shape, location and ratio of damaged landscape. For the study, the preference and landscape adjectives were analyzed on visual images and simulations. The variables for analysis were the amount of the damaged ratio(10%, 30%, 50%), the location of the damage (upper, middle, lower) and the various forms of the damage(spot, line, area). According to the results of this study, in accordance with the amount of damage, the visual preference recorded its lowest with the a rate of 50%. As for the location of the damage, the lower-ridge of the mountain showed the highest preference, and the upper-ridge was recorded as the lowest. The linear damage type showed the highest preference. On the other hand, the spotted damage type showed lowest. The results indicate that the visual preference increases when there is a lower ratio of damage, as the damage locates at the lower-ridge, and also when there is a presence of linear formation development. The group of linear formation-the lower ridge-10% showed the highest preference, and the group of linear formation-the mid ridge-50% was the lowest with the results of 3-way ANOVA. The group of linear formation-lower ridge-10% in particular had virtually no differences of visual preference when it was compared with the original scene. The damage with the spotted formation, on the mid-upper location and the high ratio of damage were analyzed as factors that give negative influence on the mountainous landscape. The main features of mountainous landscape were reduced into two factors, 'total estimation' and 'spatial scale' by the factor analysis with total variance of 65.96%.

• Structural Engineering and Mechanics
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• 제40권5호
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• pp.719-743
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• 2011

A hybrid damage monitoring scheme using parallel acceleration-impedance approaches is proposed to detect girder damage and support damage in steel plate-girder bridges which are under ambient train-induced excitations. The hybrid scheme consists of three phases: global and local damage monitoring in parallel manner, damage occurrence alarming and local damage identification, and detailed damage estimation. In the first phase, damage occurrence in a structure is globally monitored by changes in vibration features and, at the same moment, damage occurrence in local critical members is monitored by changes in impedance features. In the second phase, the occurrence of damage is alarmed and the type of damage is locally identified by recognizing patterns of vibration and impedance features. In the final phase, the location and severity of the locally identified damage are estimated by using modal strain energy-based damage index methods. The feasibility of the proposed scheme is evaluated on a steel plate-girder bridge model which was experimentally tested under model train-induced excitations. Acceleration responses and electro-mechanical impedance signatures were measured for several damage scenarios of girder damage and support damage.

• 한국지진공학회논문집
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• 제2권1호
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• pp.95-111
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• 1998

본 연구에서 구조요소 및 구조계에 대한 지진손상 해석방법의 개념 및 과정을 연구하였다. 구조요소에 대한 지진손상도 해석은 구조요소나 단자유도계에 관한 기존의 방법으로 가장 널리사용되고 있는 Park & Ang 방법에 의하여 예제구조물에 대하여 수행하였다. 구조계에 대한 지진손상도 해석을 수행하기 위해서는 두 가지의 과정을 사용하였다. 첫 번째 과정은 구조계에 해당하는 지진응답을 구조계 대표응답법과 등가단자유도계 응답법을 이용하여 구한 후, 구조계의 지진손상도는 기존의 단자유도계나 구조요소에 관한 방법을 이용하여 구조계의 지진응답으로부터 구한다. 두 번째 구조요소에 대한 지진손상도 해석결과를 손상지수 조합법을 이용하여 선형적으로 조합하여 구조계의 지진손상도를 구한다. 각 방법의 유용성은 몇 개의 다른 지진과 예제구조물에 대하여 비교를 통하여 연구하였다.

• 반도체디스플레이기술학회지
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• 제22권4호
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• pp.99-102
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• 2023

In this paper, the system is proposed and implemented to share the part number, the part name, and the vehicle type through the improvement sharing bulletin board for automobile repair and maintenance. And when photos of damage parts are uploaded to the system, the system analyzes it using a deep learning model to analyze whether it is damaged and automatically classify the type of damage. By providing repair and maintenance quotes for a significant part, the system provides economically repaired by providing comparative adjustment information on repair costs to drivers who are particularly concerned about the market prices of parts and maintenance services. Through the existing bulletin board, you can exchange and share information about parts by sharing various information on repair and maintenance. This paper provides in detail the average market price per type of damage during automobile repair and maintenance, helping drivers who do not know the details of parts and maintenance services to receive reasonable quotes by providing price information.

• 한국지반신소재학회논문집
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• 제23권2호
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• pp.29-42
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• 2024

2017년 포항지진으로 인해 액상화 현상에 의한 안벽구조물에 피해가 발생하였다. 액상화는 지진 시 과잉간극수압 증가로 인해 유효응력이 소실되어 발생하게 된다. 이에 따른 잔교식 안벽의 피해 발생 부분을 규명하며 액상화로 인한 피해를 분석하였다. 또한 개량지반의 경우 연암층과 강성차이로 인해 하부 Sand 층의 액상화 현상으로 인해 피해가 발생하여, 비액상화 지반으로 가정하고 추가적인 수치해석을 수행하였다. 과잉간극수압비의 증가에 영향을 주는 요인으로는 지반의 상대밀도 및 입력 지진가속도의 크기 등 여러 가지 원인이 있다. 따라서 본 연구는 입력가속도의 크기를 증가시켜 Case 1~3에 대해 수치해석을 수행하였고, 개량지반의 경우 하부 Sand층의 액상화 현상으로 인한 피해가 발생하여 비액상화지반으로 가정하여 분석을 수행하였다. 결과적으로, 개량지반은 하부 액상화지반이 있을 경우 추가적인 보강이 필요하며, 잔교식 안벽 말뚝의 수평변위가 약 2배 감소하는 현상이 나타났다.

• Molecules and Cells
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• 제19권2호
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• pp.167-179
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• 2005

The cells of metazoans respond to DNA damage by either arresting their cell cycle in order to repair the DNA, or by undergoing apoptosis. This response is highly conserved across species, and many of the genes involved in this DNA damage response have been shown to be inactivated in human cancers. This suggests the importance of DNA damage response with regard to the prevention of cancer. The DNA damage checkpoint responses vary greatly depending on the developmental context, cell type, gene expression profile, and the degree and nature of the DNA lesions. More valuable information can be obtained from studies utilizing whole organisms in which the molecular basis of development has been well established, such as Drosophila. Since the discovery of the Drosophila p53 orthologue, various aspects of DNA damage responses have been studied in Drosophila. In this review, I will summarize the current knowledge on the DNA damage checkpoint response in Drosophila. With the ease of genetic, cellular, and cytological approaches, Drosophila will become an increasingly valuable model organism for the study of mechanisms inherent to cancer formation associated with defects in the DNA damage pathway.

• 한국소음진동공학회논문집
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• 제20권3호
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• pp.272-278
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• 2010

A method for damage detection in a plate structure is presented based on strain waves that are generated by impact or damage in the structure. Strain responses from continuous sensors, which are long ribbon-like sensors made from piezoceramic fibers or other materials, were used with a neural network technique to estimate the damage location. The continuous sensor uses only a small number of channels of data acquisition and can cover large areas of the structure. A grid type structural neural system composed of the continuous sensors was developed for effective damage localization in a plate structure. The ratios of maximum strains and arrival times of the maximum strains obtained from the continuous sensors were used as input data to a neural network. Simulated damage localizations on a plate were carried out and the identified damage locations agreed reasonably well with the exact damage locations.

• Structural Engineering and Mechanics
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• 제38권1호
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• pp.81-97
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• 2011

In this research, the wavelet transform is used to analyze time response of a cracked beam carrying moving mass for damage detection. In this respect, a new damage detection method based on the combined use of continuous and discrete wavelet transforms is proposed. It is shown that this method is more capable in making damage signature evident than the traditional two approaches based on direct investigation of the wavelet coefficients of structural response. By the proposed method, it is concluded that strain data outperforms displacement data at the same point in revealing damage signature. In addition, influence of moving mass-induced terms such as gravitational, Coriolis, centrifuge forces, and pure inertia force along the deflection direction to damage detection is investigated on a sample case. From this analysis it is concluded that centrifuge force has the most influence on making both displacement and strain data damage-sensitive. The Coriolis effect is the second to improve the damage-sensitivity of data. However, its impact is considerably less than the former. The rest, on the other hand, are observed to be insufficient alone.

• 한국지진공학회논문집
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• 제9권5호
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• pp.53-61
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• 2005

부재의 내력비, 강성비에 영향을 받는 다층 강구조 골조의 내진성능을 평가하기 위하여 내력비 및 강성비를 설계 파라메타로 하여 동적 비탄성 응답해석을 수행하였다. 해석 결과에 대한 분석을 통하여 내력비와 강성비의 변화폭이 큰 다층골조의 손상분포 예측식을 제안하였다. 본 연구에서 얻어진 결과는 다음과 같이 요약할 수 있다. 1) 보기둥 내력비 및 강성비가 작아질수록 1층의 기둥 주각부에서의 손상집중 현상이 크게 나타났다. 2) 보기둥 내력비 및 강성비를 고려하여 보붕괴형 강구조 다층골조의 손상분포를 예측할 수 있는 식을 제안하였으며, 예측식은 응답해석 결과와 좋은 대응을 보였다. 3) 본 연구에서 제안한 손상분포 예측식은 강접 및 반강접 보붕괴형 강구조 다층골조의 손상분포를 예측할 수 있을 것으로 판단된다.