• Nuclear Engineering and Technology
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• v.53 no.1
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• pp.103-110
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• 2021

In the development of a Risk Monitor probabilistic safety assessment (PSA) model from the basic PSA model of a nuclear power plant, the modeling of common-cause failure (CCF) is very important. At present, some approximate modeling methods are widely used, but there lacks criterion of modeling accuracy and error analysis. In this paper, aiming at ensuring the accuracy of risk assessment and minimizing the Risk Monitor PSA models size, we present three basic issues of CCF model resulted from the changes of a nuclear power plant configuration, put forward corresponding modeling methods, and derive accuracy criteria of CCF modeling based on minimum cut sets and risk indicators according to the requirements of risk monitoring. Finally, a nuclear power plant Risk Monitor PSA model is taken as an example to demonstrate the effectiveness of the proposed modeling method and accuracy criteria, and the application scope of the idea of this paper is also discussed.

• Journal of KIBIM
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• v.7 no.4
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• pp.8-20
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• 2017

When it comes to set up the BIM through the reverse engineering, the level of detail(LoD) required for finalized outcomes is different from each purpose. Therefore, it is necessary to establish some concrete criteria which describe the definition of LoDs on 3D modeling for the purpose of each reverse engineering. This research shows the criteria of the 1) positional accuracy, 2) generalization level, 3) scale level, 4) scope of description, and 5) the area available for application by classifying LoD from 1 to 6 on 3D modeling for each purpose of reverse engineering. Moreover, through applying those criteria for the 3D point cloud dataset of building made by terrestrial LiDAR, this research finds out the working hour of 3D modeling of reverse engineering by each LoDs according to defined LoD criteria for each level. It is expected that those findings, how those criteria of LoD on reverse engineering are utilized for modeling-workers to decide whether the outcomes can be suitable for their budget, applicable fields or not, would contribute to help them as a basic information.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.9 no.3
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• pp.1-7
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• 2010

The aim of this research is to evaluate movement and path characteristics of developed heavy duty handling robot using laser tracker(API T3) according to the ISO 9283 robot performance evaluation criteria. As carry out 3D modeling and simulation using CATIA, a test cube was set up to select moving and measuring range of robot. Performance test for pose and distance accuracy, path and path velocity accuracy under payload zero and 440kgf was accomplished. The resulted output data show the reliability of the developed robot.

• Journal of Information Technology Services
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• v.16 no.4
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• pp.161-176
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• 2017

Recently, most of the users can easily get access to a variety of information sources about companies, products, and services through online channels. Therefore, the online user evaluations are becoming the most powerful tool to generate word of mouth. The user's evaluation is provided in two forms, quantitative rating and review text. The rating is then divided into an overall rating and a detailed rating according to various evaluation criteria. However, since it is a burden for the reviewer to complete all required ratings for each evaluation criteria, so most of the sites requested only mandatory inputs for overall rating and optional inputs for other evaluation criteria. In fact, many users input only the ratings for some of the evaluation criteria and the percentage of missed ratings for each criteria is about 40%. As these missed ratings are the missing values in each criteria, the simple average calculation by ignoring the average 40% of the missed ratings can sufficiently distort the actual phenomenon. Therefore, in this study, we propose a methodology to predict the rating for the missed values of each criteria by analyzing user's evaluation information included the overall rating and text review for each criteria. The experiments were conducted on 207,968 evaluations collected from the actual hotel evaluation site. As a result, it was confirmed that the prediction accuracy of the detailed criteria ratings by the proposed methodology was much higher than the existing average-based method.

• Computers and Concrete
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• v.32 no.3
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• pp.339-349
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• 2023

Fast-built construction is a key feature for successful applications of precast concrete (PC) moment frame system in recent construction practices. To this end, by introducing some unique splicing details in precast connections, especially between PC columns including panel zones, use of temporary supports and bracings can be minimized based on their self-sustaining nature. In addition, precast wide beams are commonly adopted for better economic feasibility. In this study, three self-sustaining precast concrete (PC) wide beam-column connection specimens were fabricated and tested under reversed cyclic loadings, and their seismic performances were quantitatively evaluated in terms of strength, ductility, failure modes, energy dissipation and stiffness degradation. Test results were compared with ASCE 41-17 nonlinear modeling curves and its corresponding acceptance criteria. On this basis, an improved macro modeling method was explored for a more accurate simulation. It appeared that all the test specimens fully satisfy the acceptance criteria, but the implicit joint model recommended in ASCE 41-17 tends to underestimate the joint shear stiffness of PC wide beam-column connection. While, the explicit joint model along with concentrated plastic hinge modeling technique is able to present better accuracy in simulating the cyclic responses of PC wide beam-column connections.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2005.10a
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• pp.288-293
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• 2005

In this study, SWAT model was applied to the Soyang Dam upstream watershed in order to evaluate the model applicability for estimating runoff, sediment, and nutrients loadings from the watershed. By trial and error method, the model parameters related with runoff, sediment, nitrogen and phosphorus were calibrated step by step. Then the simulated runoff, sediment, and nutrients loadings by the model were compared with the observed data measured at the Soyang Dam, the outlet of the watershed. And several statistical criteria were calculated to evaluate the model performance. From the comparison and statistical criteria, good agreement between simulated and observed stream flows was found. For sediment and nutrients, it was not reliable to quantitatively model the observed values, but the model could simulate the trend with reasonable accuracy. Hence, it was concluded that the model can be applied for the long-term non-point modeling in a large watershed.

• Smart Structures and Systems
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• v.15 no.6
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• pp.1439-1461
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• 2015

Design criteria, modeling rules, and analysis principles of seismic isolation systems have already found place in important building codes and standards such as the Uniform Building Code and ASCE/SEI 7-05. Although real behaviors of isolation systems composed of high damping or lead rubber bearings are nonlinear, equivalent linear models can be obtained using effective stiffness and damping which makes use of linear seismic analysis methods for seismic-isolated buildings possible. However, equivalent linear modeling and analysis may lead to errors in seismic response terms of multi-story buildings and thus need to be assessed comprehensively. This study investigates the accuracy of equivalent linear modeling via numerical experiments conducted on generic five-story three dimensional seismic-isolated buildings. A wide range of nonlinear isolation systems with different characteristics and their equivalent linear counterparts are subjected to historical earthquakes and isolation system displacements, top floor accelerations, story drifts, base shears, and torsional base moments are compared. Relations between the accuracy of the estimates of peak structural responses from equivalent linear models and typical characteristics of nonlinear isolation systems including effective period, rigid-body mode period, effective viscous damping ratio, and post-yield to pre-yield stiffness ratio are established. Influence of biaxial interaction and plan eccentricity are also examined.

• Journal of Physiology & Pathology in Korean Medicine
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• v.28 no.1
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• pp.76-81
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• 2014

The aim of this study was to build the diagnosis criteria of Qi deficiency using distribution of sum of 11 items for Qi deficiency in stroke patients. Between September 2006 and December 2010, 2,994 patients from 11 Korean medical hospitals were asked to complete the Korean Standard Pattern Identification for Stroke (K-SPI-Stroke) questionnaire as a part of project 'Fundamental study for the standardization and objectification of pattern identification in traditional Korean medicine for stroke (SOPI-Stroke). Each patient was independently diagnosed by two experts (traditional Korean medicine physicians) from the same site according to one of five patterns. 2,994 patients were divided modeling and testing in 70:30 ratio by stratification of pattern identification. We calculated the sensitivity, specificity, accuracy and odds ratio (OR) using distribution of sum of 11 items (signs and symptoms) for Qi deficiency. More than four from 11 items of Qi deficiency in modeling dataset, sensitivity, specificity, accuracy and OR was 70.07%, 74.94%, 73.92% and 7.00, respectively. In testing dataset, 78.31%, 73.45%, 74.47% and 9.98, respectively. Although this values are not high, after values of sensitivity, specificity, accuracy and OR should be more than current value, and then we should be able to suggest as objective diagnosing criteria.

• Spatial Information Research
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• v.18 no.4
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• pp.13-22
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• 2010

For implementing TMDL(Total Maximum Daily Loading) to adopt more effective management of water pollution, water quality modeling is pre-requisite and such modeling requires the extraction of stream centerline. The institutes responsible for the water quality modeling, however, generates the stream centerline with their own criteria and this lead to low accuracy of the extracted centerline as well as different modeling results for the same watershed. Therefore, this study mainly focused on the development of extraction method of the stream centerline. For that, an automated method has been developed through the integration of the centerline extraction method using a maximum inscribed circle with GIS. The result has shown that the newly developed method could enable to represent more details of the stream topography along with enhanced accuracy compared with conventional extraction method. Furthermore, the new method can afford centerline extraction for the island areas which has been the limitation of the conventional method thereby supporting water quality modeling in a detailed level.

• Journal of Korea Multimedia Society
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• v.18 no.7
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• pp.886-894
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• 2015

In this paper, we conduct sensitivity analysis of parameters used for inverse modeling in order to estimate the PM₁₀ emissions from the 16 areas in East Asia accurately. Parameters used in sensitivity analysis are R, the observational error covariance matrix, and B, a priori (background) error covariance matrix. In previous studies, it was used with the predetermined parameter empirically. Such a method, however, has difficulties in estimating an accurate emissions. Therefore, an automatically determining method for the most suitable value of R and B with an error measurement criteria and posteriori emissions accuracy is required. We determined the parameters through a sensitivity analysis, and improved the accuracy of posteriori emissions estimation. Inverse modeling methods used in the emissions estimation are pseudo inverse, NNLS (Nonnegative Least Square), and BA(Bayesian Approach). Pseudo inverse has a small error, but has negative values of emissions. In order to resolve the problem, NNLS is used. It has a unrealistic emissions, too. The problems are resolved with BA(Bayesian Approach). We showed the effectiveness and the accuracy of three methods through case studies.