• 한국항해항만학회지
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• 제36권10호
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• pp.803-810
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• 2012

냉동컨테이너 화물의 해상운송이 증가함에 따라 냉동컨테이너 화물의 손상과 관련된 분쟁 및 클레임이 화물 소유자인 화주와 화물운송의 주체인 운송인 간에 빈번하게 발생하고 있는 실정이다. 냉장 냉동화물은 그 특성상 다른 일반화물에 비해 화물손상에 대한 분쟁 및 클레임이 많은 편이며, 일단 화물손상이 발생하면 관련 당사자들에게 분쟁이나 클레임으로 인한 불필요한 시간낭비 및 물류비용 즉, 손상화물의 검사비용, 손상화물의 폐기비용, 클레임관련 소송비용 등 불필요한 경제적 비용을 증가시킨다. 따라서 본 연구의 목적은 냉동컨테이너 화물손상의 개선방안을 모색하여 해상으로 운송되고 있는 냉동컨테이너 화물의 손상을 사전에 예방해 화물손상으로 인한 불필요한 물류비용 및 시간낭비를 감소시킴과 동시에 냉동컨테이너 화물을 목적지까지 보다 안전하고 효율적으로 운송하여 원활한 물류흐름에 기여하는데 있다.

• 환경정책연구
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• 제9권1호
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• pp.31-55
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• 2010

기후변화 정책 분석 모델 (PAGE, Policy Analysis of Greenhouse Effect)을 이용해 여러 온실가스 배출 시나리오에 따른 기후변화의 피해 비용을 분석했다. 국내외 기후변화 영향에 관한 선행 연구 결과에 따르면 한국의 기후변화의 민감도는 경제 협력개발기구(OECD) 회원국들과 유사한 수준이 될 것으로 전망되었으나 구체적인 한국의 분야별 영향평가가 이루어져야 보다 정량적인 기후변화의 피해함수 추정이 가능할 것이다. 온실가스 배출량, 이산화황 배출량, 적응정책의 정도, 경제 성장, 인구 성장 등 많은 인자들이 기후변화로 인한 피해 정도에 영향을 미친다. 본 연구에서는 PAGE 모델을 이용해 미래의 여러 상황에 따른 기후변화의 피해 정도를 알아보기 위하여 A2, B1, Kyoto, 3가지 시나리오에 대한 분석을 하였다. 만일 전 세계가 온실가스 감축을 위한 아무 대책도 실행하지 않는다면 2100년 한국은 약 3도 정도의 온도상승이 예측되고 이로 인해 12조에서 58조정도의 피해가 일어날 것으로 분석되었다. 1990년에서 2100년까지 기후변화로 인한 누적 피해비용은 약 143조에서 921조에 이를 것으로 분석되었다.그러나 이는 소수의 피해함수에 대한 연구결과만을 반영해 산정한 결과며 분야별로 더 많은 연구가 수행되어야 보다 신뢰도 높은 피해비용을 산정할 수 있다.

• Smart Structures and Systems
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• 제18권6호
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• pp.1233-1250
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• 2016

Cracks in plate-like structures are some of the main reasons for destruction of the entire structure. In this study, a novel two-stage methodology is proposed for damage detection of flexural plates using an optimized artificial neural network. In the first stage, location of damages in plates is investigated using curvature-moment and curvature-moment derivative concepts. After detecting the damaged areas, the equations for damage severity detection are solved via Bat Algorithm (BA). In the second stage, in order to efficiently reduce the computational cost of model updating during the optimization process of damage severity detection, multiple damage location assurance criterion index based on the frequency change vector of structures are evaluated using properly trained cascade feed-forward neural network (CFNN) as a surrogate model. In order to achieve the most generalized neural network as a surrogate model, its structure is optimized using binary version of BA. To validate this proposed solution method, two examples are presented. The results indicate that after determining the damage location based on curvature-moment derivative concept, the proposed solution method for damage severity detection leads to significant reduction of computational time compared with direct finite element method. Furthermore, integrating BA with the efficient approximation mechanism of finite element model, maintains the acceptable accuracy of damage severity detection.

• Smart Structures and Systems
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• 제26권1호
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• pp.23-33
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• 2020

Majority of the damage in engineering structures is nonlinear. Damage sensitive features (DSFs) extracted by traditional methods from linear time series models cannot effectively handle nonlinearity induced by structural damage. A new DSF is proposed based on vector space cosine similarity (VSCS), which combines K-means cluster analysis and Bayesian discrimination to detect nonlinear structural damage. A reference autoregressive moving average (ARMA) model is built based on measured acceleration data. This study first considers an existing DSF, residual standard deviation (RSD). The DSF is further advanced using the VSCS, and then the advanced VSCS is classified using K-means cluster analysis and Bayes discriminant analysis, respectively. The performance of the proposed approach is then verified using experimental data from a three-story shear building structure, and compared with the results of existing RSD. It is demonstrated that combining the linear ARMA model and the advanced VSCS, with cluster analysis and Bayes discriminant analysis, respectively, is an effective approach for detection of nonlinear damage. This approach improves the reliability and accuracy of the nonlinear damage detection using the linear model and significantly reduces the computational cost. The results indicate that the proposed approach is potential to be a promising damage detection technique.

• 한국해안·해양공학회논문집
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• 제22권5호
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• pp.295-305
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• 2010

국내 경사식 방파제는 거의 매년 태풍 피해를 지속적으로 입고 있지만 피복블록의 침식피해를 정량적으로 분석한 사례가 드물다. 본 논문에서는 피복블록의 침식을 상대피해로 표준화하여 나타내었다. 블록의 이탈 개수가 조사된 경우에는 이를 블록의 전체 개수로 나누어 상대피해를 계산하였으며, 피해 복구 비용이 조사된 경우에는 현재 가치로 환산한 복구 비용과 상대피해의 관계를 이용하여 상대피해를 산정하였다. 상대 피해는 태풍 매개변수인 중심기압 및 최대풍속과 지역별로 뚜렷한 상관관계를 보였다. 또한 기존 누적 피해 계산 방법 중에서 합리적 방법을 선정하기 위해 수리모형 실험결과와 두 가지 수치 모의 방법을 비교하였다. 본 연구에서 Melby and Kobayashi (1998) 방법이 합리적임을 증명하였고 이 방법으로 계산된 상대피해를 관측된 상대피해와 비교하였다. 여수항 동방파제에서 관측된 상대피해와 수치 모의 결과는 잘 일치하지만 나머지 방파제에서는 상당한 차이를 보였다. 이는 기후변화에 따른 태풍 강도의 증가로 방파제의 설계파고보다 큰 파고가 사용년수 동안에 발생하여 실제 상대피해가 증가된 것으로 추정된다.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2006년도 정기 학술대회 논문집
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• pp.549-556
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• 2006

Life cycle cost is one of important factors in the evaluation of economy feasibility. Load carrying capacity curves for girders and decks are derived on the basis of bridge diagnostic results and condition grade curves to determine the service life and life cycle profile. The total life cycle costs including initial cost, damage cost, maintenance cost, user cost, and etc for the service life are calculated for steel box girder, PSC-I girder and rationalized plate girder. The optimal designs are performed for various service lifes and different superstructure types. The effects of parameters on the life cycle cost are investigated and the economy feasibility is evaluated through the sensitivity analysis.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 춘계학술대회논문집
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• pp.577-582
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• 2001

Identification of damage of structures has recently received considerable attention in the light of maintenance and safety assessment under service loads. In buildings, the current techniques of safety assessment largely depend on partial experiments such as visual inspection, destructive and nondestructive tests which lead to overconsumption of time and cost as well as higher labor intensity. Therefore, a new trial for safety assessment is urgently needed today. In this respect, the vibration characteristics of buildings have been applied steadily to obtain a damage index of the whole building, but it cannot be established as a practical method until now. This study is aimed at investigating the application of damage identification methods using vibration characteristics of building. Numerical tests are performed on a apartment building. From the test results, it is observed that severity and location of damage can be estimated with a relatively small error by using natural frequency and mode shape data.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 1996년도 International Conference on Agricultural Machinery Engineering Proceedings
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• pp.878-885
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• 1996

The brown rice drying is effective for energy saving and cost reduction. However, deterioration after drying is one problem, because the skin damage occurs during the drying. So, the measures to preserve the quality has been investigated. One of major quality deteriorations is the oxidation of fat which is contained in the bran layer. So, milling should be carried out to remove the fat as soon as possible after brown rice drying. And the low temperature storage is also worth to be examined for prevention of oxidation. The effect of skin damage on the increase of fat oxidation was clarified. For the grain of skin damage, the increased of fatty acid vaule was remarkable after 70 days elapsed from occurrence of skin damage even in $15\;^{\circ}C$ condition. Therefore it is impossible to keep grain as brown rice form after brown rice drying. For the clean rice and excessively milled rice, the quality can be preserved even in high temperature of $30\;^{\circ}C$. Therefore the brown rice drying can b applied practically using the clean rice technique.

• Transactions on Electrical and Electronic Materials
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• 제3권4호
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• pp.1-4
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• 2002

As the application of semiconductor chips into electronics increases, it requires more complete integration, which results in higher performance. And it needs minimization in device design for cost saving of manufacture. Therefore oxide gap fill has become one of the major issues in sub-micron devices. Currently HDP (High-Density Plasma) CVD system is widely used in IMD (Inter Metal Dielectric) to fill narrower space between metal lines. However, HDP-CVD system has some potential problems such as plasma charging damage, metal damage and etc. Therefore, we will introduce about one of via resistance failure by metal damage and a preventive method in this paper.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2002년도 봄 학술발표회 논문집
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• pp.263-270
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• 2002

During deep excavation, changes in the state of stress in the ground mass around the excavation and subsequent ground losses inevitably occur. These changes in the stress and ground losses are reflected on surrounding ground in the form of ground movements, which eventually Impose strains onto nearby structures through translation, rotation, distortion, and possibly damage. A substantial portion of the cost of deep excavations in urban environments is, therefore, devoted to prevent ground movements. Prediction of ground movements and assessment of the risk of damage to adjacent structures has become an essential part of the planning, design, and construction of a deep excavation project in the urban environments. This paper presents excavation-induced ground movement characteristics as well as important issues related to excavation-induced building damage assessment.