• Journal of architectural history
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• v.21 no.2
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• pp.37-52
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• 2012

This research has set up the fire fighting general index for Fire fighting of Crowded Wooden Building Cultural Asset which is composed of traditional wooden building instinct or complex. The results of this study are as follows. First, Fire fighting general index for crowded wooden building cultural asset, it is necessary to set fire fighting priority by considering fire risk and cultural asset characteristic and establish the system to cope with fire disaster in the most effective way by arranging facilities with restricted resource. Second, Fire risk is the index to draw fire and spread risk of cultural asset by applying index calculation processes such as fire load, burning velocity and ignition material spread characteristic to various aspects such as individual building and complex and combining their results. Cultural asset importance index consists of individual building evaluation, publicity security degree, area importance evaluation and historical landscape degree evaluation. Third, for each index combination process, weight of each index is drawn on the basis of AHP analysis result that is performed to the specialists of related fields. The formula to apply and combine it is prepared to apply the model to include meaning of each index and comparative importance degree.

• Journal of the Korean Operations Research and Management Science Society
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• v.28 no.2
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• pp.17-33
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• 2003

The explosive growth of the internet-based transactions requires not only a secure payment system but also an appropriate trust measuring methodology and secure transaction protocols to guarantee the minimal risk for the transacting entities involved in specific transactions. Especially, in internet auction systems where either buyers or sellers or both can be more than one in one transaction, providing those systems that make sure no one transacting entity takes a major risk becomes critical. In this paper, an improved trust measuring method using a relationship-based internet community for an auction system is proposed. The proposed system incorporates fuzzy set and calculation concepts to help build trust matrices and models, which is used to measure the level of risk involved in a specific auction trade concerned. Also, to optimize the auction trade process in terms of cost and time, the proposed system recommends a differentiated trade protocol according to the risk level involved in each auction trade. To test the appropriateness of the proposed trusted auction system, a prototype system has been developed under a Windows-NT environment.

• The Korean Journal of Applied Statistics
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• v.34 no.6
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• pp.875-887
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• 2021

Value at Risk (VaR) is the most popular measure for market risk. In this paper, we consider the VaR estimation of portfolio consisting of a variety of assets based on multivariate copula model known as vine copula. In particular, sparse vine copula which penalizes too many parameters is considered. We show in the simulation study that sparsity indeed improves out-of-sample forecasting of VaR. Empirical analysis on 60 KOSPI stocks during the last 5 years also demonstrates that sparse vine copula outperforms regular copula model.

• Geomechanics and Engineering
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• v.37 no.6
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• pp.565-576
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• 2024

In this study, the earthquake risk assessment of single-story RC precast buildings in Turkey was carried out using loss curves. In this regard, Kocaeli, a seismically active city in the Marmara region, and this building class, which is preferred intensively, were considered. Quality and period parameters were defined based on structural and geometric properties. Depending on these parameters, nine main sub-classes were defined to represent the building stock in the region. First, considering the mean fragility curves and four different central damage ratio models, vulnerability curves for each sub-class were computed as a function of spectral acceleration. Then, probabilistic seismic hazard analyses were performed for stiff and soft soil conditions for different earthquake probabilities of exceedance in 50 years. In the last step, 90 loss curves were derived based on vulnerability and hazard results. Within the scope of the study, the comparative parametric evaluations for three different earthquake intensity levels showed that the structural damage ratio values for nine sub-classes changed significantly. In addition, the quality parameter was found to be more effective on a structure's damage state than the period parameter. It is evident that since loss curves allow direct loss ratio calculation for any hazard level without needing seismic hazard and damage analysis, they are considered essential tools in rapid earthquake risk estimation and mitigation initiatives.

• Journal of the Korean Institute of Landscape Architecture
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• v.51 no.2
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• pp.1-11
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• 2023

This study intended to develop a technique for quantitatively and 3-dimensionally predicting the potential failure zone and impulse that may occur when trees are fall down. The main outcomes of this study are as follows. First, this study established the potential failure zone and impulse calculation formula in order to quantitatively calculate the risks generated when trees are fallen down. When estimating the potential failure zone, the calculation was performed by magnifying the height of trees by 1.5 times, reflecting the likelihood of trees falling down and slipping. With regard to the slope of a tree, the range of 360° centered on the root collar was set in the case of trees that grow upright and the range of 180° from the inclined direction was set in the case of trees that grow inclined. The angular momentum was calculated by reflecting the rotational motion from the root collar when the trees fell down, and the impulse was calculated by converting it into the linear momentum. Second, the program to calculate a potential failure zone and impulse was developed using Rhino3D and Grasshopper. This study created the 3-dimensional models of the shapes for topography, buildings, and trees using the Rhino3D, thereby connecting them to Grasshopper to construct the spatial information. The algorithm was programmed using the calculation formula in the stage of risk calculation. This calculation considered the information on the trees' growth such as the height, inclination, and weight of trees and the surrounding environment including adjacent trees, damage targets, and analysis ranges. In the stage of risk inquiry, the calculation results were visualized into a three-dimensional model by summarizing them. For instance, the risk degrees were classified into various colors to efficiently determine the dangerous trees and dangerous areas.

• 유체기계공업학회:학술대회논문집
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• 2006.08a
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• pp.279-282
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• 2006

Upon a turbopump's running, cavitation may occur at the inlet of the LOx pump by pressure drop and heat transfer along the LOx feeding line. Since the cavitation can cause serious damage to the pump or to stop running, the absence of the cavitation at the inlet of a turbopump should be confirmed before the using the turbopump. In the present study, the calculation of the volume fraction of LOx gas phase at the inlet of the pump are performed with different temperatures of LOx in the tank, pressure drops and heat transfers along the feeding line. This calculation method can be applied to define the limits of thermal and hydraulic characteristics during the design of a LOx feeding system.

• Journal of Radiation Protection and Research
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• v.46 no.4
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• pp.151-159
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• 2021

Background: Computed tomography (CT) is one of the crucial diagnostic tools in modern medicine. However, careful monitoring of radiation dose for CT patients is essential since the procedure involves ionizing radiation, a known carcinogen. Materials and Methods: The most desirable CT dose descriptor for risk analysis is the organ absorbed dose. A variety of CT organ dose calculators currently available were reviewed in this article. Results and Discussion: Key common elements included in CT dose calculators were discussed and compared, such as computational human phantoms, CT scanner models, organ dose database, effective dose calculation methods, tube current modulation modeling, and user interface platforms. Conclusion: It is envisioned that more research needs to be conducted to more accurately map CT coverage on computational human phantoms, to automatically segment organs and tissues for patient-specific dose calculations, and to accurately estimate radiation dose in the cone beam computed tomography process during image-guided radiation therapy.

• Korean Journal of Construction Engineering and Management
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• v.17 no.2
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• pp.90-98
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• 2016

High-rise buildings construction project have various risk factors. Major risk factors are negative results such as time delay and increase of costs. Therefore, this study was analyzed risk factors in construction stages of high-rise buildings using by PROMETHEE technique. For this, this research were identified risk factors through experts Focus Group Interview(FGI). And, PROMETHEE was used to setup evaluation standard for analysis of high-rise building construction risks. Next, the standard of evaluation index calculation was composed by using the definition level in PDRI. Preference function and evaluation index were identified through questionnaires. Through these processes, this study has calculated the importance of high-rise building construction risks using by PROMETHEE technique. As a result, high degree risk factors were as following. These are 'Operation plan of material lifting', 'Outrigger & Belt Truss Construction', 'Foundation work plan of high-rise building' and 'Considering a Structure concept of high-rise building'.

• Nuclear Engineering and Technology
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• v.21 no.3
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• pp.171-185
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• 1989

On the basis of equal health hazard risk, economic assessment of nuclear was compared with that of coal for the expansion planning of electric power generation in the year 2000. In comparing health risks, the risk of coal was roughly ten times higher than that of nuclear according to various previous risk assessments of energy system. The zero risk condition can never be achievable. Therefore, only excess relative health risk of coal over nuclear was considered as social cost. The social cost of health risk was estimated by calculation of mortality and morbidity costs. Mortality cost was ＄250,000 and morbidity cost was ＄90,000 in the year 2000.(1986US＄) Through Cost/Benefit Analysis, the optimal emission standards of coal-fired power generation were predicted. These were obtained at the point of least social cost for power generation. In the year 2000, the optimal emission standard of SOx was analyzed as 165ppm for coal-fired power plants in Korea. From this assessment, economic comparison of nuclear and coal in the year 2000 showed that nuclear would be more economical than coal, whereas uncertainty of future power generation cost of nuclear would be larger than that of coal.

• The Journal of Engineering Geology
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• v.29 no.3
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• pp.289-302
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• 2019

As the occurrence of ground subsidence near the excavation site increases recently, studies are being conducted to predict the possibility of ground subsidence prior to excavation. In this study, the ground subsidence risk rating for pre-excavation (GSRp) developed by the previous study was applied to actual excavation sites to verify its applicability. The final results for the evaluation of the ground subsidence risk level for five excavation sites revealed that GSRp scores were calculated between 40 and 79 points and classified mainly into grades II (Good Ground)~III (Fair Ground). In order to verify the evaluation method, the obtained GSRp grades were compared with the measured horizontal displacements. The horizontal displacements measured in five excavation sites were between 25% and 47% of the allowable displacement, which were well agreed with the low subsidence risk level obtained from GSRp calculation. It is expected that the GSRp method can be used as an evaluation tool for predicting the risk of ground subsidence before excavation if GSRp is verified and supplemented through the additional research for the poor soil with the high risk of ground subsidence.