• Journal of the Korean Institute of Navigation
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• v.21 no.3
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• pp.83-90
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• 1997

Damage stability is generally very important as a part of rescue technique of damaged ship and also in connection with the requirements of MARPOL73/78[2]. Damage stability calculation program has been developed and suggest, which can be used on an onboard computer for any operating drafts. The program is based on lost buoyancy method for calculation of final drafts, and also based on added mass method for calculation of residual righting arm. The numerical method suggested by Hamamoto-Kim[6] is adopted for calculation of intact righting arm(GZ). The model experiments on damage stability are also carried out in a small tank with tanker model 2.385 meters long. The experimental results are compared with the calculations by the suggested method.

• The Journal of Fisheries Business Administration
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• v.37 no.1 s.70
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• pp.25-44
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• 2006

Under the provision of Article 63 of the Enforcement Regulation of the Act on Acquisition and Compensation of Land and Others for Public Project that is recently enacted and implemented (hereinafter referred to as the 'Lend Compensation Act') the compensation is required to make 'When the Actual Damage Amount' is confirmed for the damage in fishery affairs that is outside of the public project area. The compensation for fishery business on the indirect damage area has been excluded from the advance compensation subject to conflict with the existing laws on fishery business compensation with the controversy in method, procedure, time and others to confirm the actual damage amount, and it lacks the standard of calculation for detailed compensation on partial damages outside of business implementation area, which caused the ceaseless conflicts and straggles between the project implementation party and the victimized fishermen regarding the calculation method of damages, standard, compensation period and others. In particular, from the numerous problems in damage compensation in fishery on the indirect damage area, the most recent problem emerged is the issue on application method of damage period in calculating the damage compensation amount that the struggle has been deepened with the differences between the project implementation party and the victimized fishermen without the stipulation on the compensation, that caused the difficulties in carrying out the public project and other serious social problems. In this study, the reasonable application method for the damage period and the calculation plan of the damage amount for calculating the damages on fishery industry outside of the public project implementation zone that is not fully specified under the Land Compensation Act, and the indirect damage area is not influenced for the notification of project recognition, and the compensation to undertake with the damage in the fishery industry in project implementation area to have the nature of damage compensation, the right to engage in fishery industry has the perpetual nature of rights, the fishery damage compensation system of Japan also recognizes the perpetual right on fishery industry to calculate the compensation amount, and the compensation for damage amount has been exercised for the period of actual damage occurrence period regardless of remaining effective period for most of fishery permit and license for fishery compensation outside of the project implementation area following the recent various public projects as well as the development process of theory on fishery loss compensation that the calculation of damage amount on the fishery industry outside of the project implementation zone would be prudent to compensate by calculating the applicable damages during the period of actual damages, and by doing so, the 'just compensation' guaranteed under the Constitution may be materialized. Therefore, the calculation of the damages from the implementation of the public project shall consider the actual period of damages and the degree of damage from the public project to calculate by the income capitalization method, however, considering the equitable consideration with the compensation following the cancellation, it shall not exceed the compensation following the termination of the applicable fishery businesses. Furthermore, the calculation method of partial damage amount on the fishery business following the project implementation shall apply, depending on the period of damage occurrence, by (1) the case of calculating the future damage amount at the present time, and (2) calculating the damage from the past to the present time as well as the damage to be incurred later, by selecting the calculation method for damages following the damage occurrence type.

• Journal of Ocean Engineering and Technology
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• v.32 no.3
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• pp.151-157
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• 2018

Offshore structures are exposed to low- and high-frequency responses due to environmental loads, and fatigue damage models are used to calculate the fatigue damage from these. In this study, we tried to optimize the main parameters used in fatigue damage calculation to derive a new fatigue damage model. A total of 162 bi-modal spectra using the elliptic equation were defined to describe the response of offshore structures. To calculate the fatigue damage from the spectra, time series were generated from the spectra using the inverse Fourier transform, and the rain-flow counting method was applied. The considered optimization variables were the size of the frequency increments, ratio of the time increment, and number of repetitions of the time series. In order to obtain optimized values, the fatigue damage was calculated using the parameter values proposed in previous work, and the fatigue damage was calculated by increasing or decreasing the proposed values. The results were compared, and the error rate was checked. Based on the test results, new values were found for the size of the frequency increment and number of time series iterations. As a validation, the fatigue damage of an actual tension spectrum found using the new proposed values and fatigue damage found using the previously proposed method were compared. In conclusion, we propose a new optimized calculation process that is faster and more accurate than the existed method.

• Journal of the Earthquake Engineering Society of Korea
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• v.21 no.4
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• pp.189-195
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• 2017

In the seismic design of building structural members, due to the complexity of the placement of PC steels in prestressed concrete members, it is necessary to review and define the definition of member damage in comparison with reinforced concrete members. In this study, the results of past experiments compared with the calculation results by 'section Analysis Method', with the aim of reviewing the precision of calculation results when member damage evaluation is performed using the section analysis method. Furthermore, it is also compared with the calculation results by the 'split Element Method'. In addition, parametric studies were carried out, and the influence of the difference between the amount of PC steels and reinforced bar on the residual strain was examined.

• Smart Structures and Systems
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• v.24 no.4
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• pp.475-490
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• 2019

The detection of structural damage without a priori information on the healthy state is challenging. In order to address the issue, the study presents a baseline-free approach to detect damage in beam structures based on an actual influence line. In particular, a multi-segment function-fitting calculation is developed to extract the actual deflection influence line (DIL) of a damaged beam from bridge responses due to a passing vehicle. An intact basis function based on the measurement position is introduced. The damage index is defined as the difference between the actual DIL and a constructed function related to the intact basis, and the damage location is indicated based on the local peak value of the damage index curve. The damage basis function is formulated by using the detected damage location. Based on the intact and damage basis functions, damage severity is quantified by fitting the actual DIL using the least-square calculation. Both numerical and experimental examples are provided to investigate the feasibility of the proposed method. The results indicate that the present baseline-free approach is effective in detecting the damage of beam structures.

• Structural Engineering and Mechanics
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• v.81 no.6
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• pp.665-675
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• 2022

The safety problems of giant hydraulic structures such as dams caused by terrorist attacks, earthquakes, and wars often have an important impact on a country's economy and people's livelihood. For the national defense department, timely and effective assessment of damage to or impending damage to dams and other structures is an important issue related to the safety of people's lives and property. In the field of damage assessment and vulnerability analysis, it is usually necessary to give the damage assessment results within a few minutes to determine the physical damage (crack length, crater size, etc.) and functional damage (decreased power generation capacity, dam stability descent, etc.), so that other defense and security departments can take corresponding measures to control potential other hazards. Although traditional numerical calculation methods can accurately calculate the crack length and crater size under certain combat conditions, it usually takes a long time and is not suitable for rapid damage assessment. In order to solve similar problems, this article combines simulation calculation methods with machine learning technology interdisciplinary. First, the common concrete gravity dam shape was selected as the simulation calculation object, and XFEM (Extended Finite Element Method) was used to simulate and calculate 19 cracks with different initial positions. Then, an LSTM (Long-Short Term Memory) machine learning model was established. 15 crack paths were selected as the training set and others were set for test. At last, the LSTM model was trained by the training set, and the prediction results on the crack path were compared with the test set. The results show that this method can be used to predict the crack propagation path rapidly and accurately. In general, this article explores the application of machine learning related technologies in the field of mechanics. It has broad application prospects in the fields of damage assessment and vulnerability analysis.

• Journal of Welding and Joining
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• v.26 no.3
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• pp.67-73
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• 2008

Fatigue life evaluation of welded structures in a range of high cycles is one of the most difficult problems since extremely small plastic deformation and damage occur during the loading cycles. Moreover, it is very difficult to identify the strong non-linearities of welding, inducing residual stress. In this paper, numerical fatigue test method for welded structures was developed using continuum damage mechanics with inherent strain. Recently, continuum damage mechanics, which can simulate both crack initiation at the micro-scale level and crack propagation at the meso-scale level, has been adopted in the fracture related problem. In order to consider the residual stresses in the welded strictures, damage calculation in conjunction with welding, inducing inherent strain, was proposed. The numerical results obtained from the damage calculation were compared to experimental results.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.5
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• pp.203-208
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• 2018

In this paper, we selected power and power distribution facilities corresponding to urban infrastructure from the types of damage that could be caused by earthquakes and studied how they were calculated to damage. To calculate the damage, a graph of the magnitude of the damage was produced by applying the vulnerability curve calculation formula, which can be calculated for each type and type of facility. The scale of the earthquake and the probability of the occurrence of damage by the maximum earthquake acceleration were shown in the form of a vulnerability rate when the earthquake occurred in the urban infrastructure facility for utilizing the calculation result. It also applied a method of quantifying the fragility, which is a method of converting the calculated fragility into an integrated form, to represent a constant value for the magnitude of the damage. Continuing research, such as the method applied in this paper, could help identify in advance the types of structures affected by an earthquake and respond to reducing damage.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.38 no.5
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• pp.741-749
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• 2018

The purpose of this study is to propose a rational and scientific damage calculation model in relation to damages caused by bid rigging in construction projects. Previous studies and precedents in relation to calculating damages from bid rigging suggest that the main issue was the lack of consideration in standards for deciding successful bids, selection of inadequate standard comparative markets, insufficiency in analyzing the appropriateness of competitive bid price influence factors, and absence of calculation model verification. In order to improve on these issues, a damage calculation method on alternative tenders for construction projects was proposed. For this calculation model, first, a standard market adequate to the successful bid selection standards was determined, second, an appropriate factor was selected by analyzing the correlation between competitive bid price influence factors, and third, a regression analysis was conducted on the selected factor. Lastly, this was demonstrated through verification of appropriateness, significance & normality of the proposed model and application of actual bid rigging cases. Through the proposed calculation model, this study seeks to serve as a base to prevent opportunity damages for parties involved in related court cases by early resolution of disputes and relief from issues of unfair damage burdens on a particular party.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.6
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• pp.1053-1061
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• 2017

The study is concerned with providing the improvement method on making a reasonable and scientific decision on the damages accrued from the bid rigging in the construction work. According to the review on the precedent studies and decision cases on the damages caused by bid rigging, the representative problems include the insufficiency of the classification system on the damage calculation method and the omission of the necessary stage in the damage determination process. First, the improved classification system on calculating the damages caused by bid rigging is presented with the application to the bid rigging in the construction work by adding the ratio factor in addition to the damage calculation parameters such as price and cost. Second, the standard procedures organized with six stages is presented as the process required for determining the damages if the indemnification for bid rigging is claimed. The study becomes the foundation for resolving the problem with the undue burden on a party and for preventing the opportunity loss by resolving a dispute early through the improvement classification system and standard procedures presented in the study.