• Structural Engineering and Mechanics
• /
• v.41 no.1
• /
• pp.25-41
• /
• 2012

Kriging surrogate model provides explicit functions to represent the relationships between the inputs and outputs of a linear or nonlinear system, which is a desirable advantage for response estimation and parameter identification in structural design and model updating problem. However, little research has been carried out in applying Kriging model to crack identification. In this work, a scheme for crack identification based on a Kriging surrogate model is proposed. A modified rectangular grid (MRG) is introduced to move some sample points lying on the boundary into the internal design region, which will provide more useful information for the construction of Kriging model. The initial Kriging model is then constructed by samples of varying crack parameters (locations and sizes) and their corresponding modal frequencies. For identifying crack parameters, a robust stochastic particle swarm optimization (SPSO) algorithm is used to find the global optimal solution beyond the constructed Kriging model. To improve the accuracy of surrogate model, the finite element (FE) analysis soft ANSYS is employed to deal with the re-meshing problem during surrogate model updating. Specially, a simple method for crack number identification is proposed by finding the maximum probability factor. Finally, numerical simulations and experimental research are performed to assess the effectiveness and noise immunity of this proposed scheme.

• 한국기계연구소 소보
• /
• s.9
• /
• pp.183-191
• /
• 1982

This report describes the analysis method of the full-scale propulsive performance by using the data of model test and the full-scale speed trial. The model test data were analyzed by the computer program "PPTT" based on "1978 ITTC Performance Prediction Method for Single Screw Ships." Also the full-scale speed trial data were analyzed by the computer program "SSTT" based on the newly proposed “SRS-KIMM Standard Method of Speed Trial Analysis." An analysis of model and full-scale test data was carried out for a 60.000 DWT Bulk Carrier and the correlation between model and full-scale ship was stuied.

• Computational Structural Engineering : An International Journal
• /
• v.1 no.2
• /
• pp.81-87
• /
• 2001

A framework for reliability analysis of structural components and systems under conditions of statistical and model uncertainty is presented. The Bayesian parameter estimation method is used to derive the posterior distribution of model parameters reflecting epistemic uncertainties. Point, predictive and bound estimates of reliability accounting for parameter uncertainties are derived. The bounds estimates explicitly reflect the effect of epistemic uncertainties on the reliability measure. These developments are enhance-ments of second-moment uncertainty analysis methods developed by A. H-S. Ang and others three decades ago.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2000.10a
• /
• pp.320-324
• /
• 2000

Nonlinear stress analysis of nuclear containment building is carried out using microscopic concrete material model. The present study mainly focuses on the evaluation of the ultimate pressure capacity of idealized containment building in nuclear power plant. For this purpose, an eight-node degenerated shell element it adopted and an imaginary opening in the apex of containment building is allowed in FE model. From numerical analysis, the adopted concrete material model performs well and has a good agreement with the result obtained by using ABAQUS. Finally, we propose the present study as a benchmark test for nonlinear analysis of containment building.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1996.11a
• /
• pp.69-73
• /
• 1996

Tool wear monitoring is very important aspect in metal cutting because tool wear effects quarity and precision of workpiece, tool life etc. In this study we detected force signal through tool dynamometer in turning and using it we conducted 6th AR modeling and fractal analysis. Finally the back-propagation model of the neural network is utilized to monitor tool wear and features are extracted through AR model and fractal analysis.

• Proceedings of the KSR Conference
• /
• 2009.05b
• /
• pp.517-524
• /
• 2009

This paper proposes a magnetic analysis model and design method of transformer for the high-speed EMU. It has a many part of the consideration in design because the transformer in high-speed train has the multiple output. Also the output characteristic, weight, and size of transformer is an important factor. This research proposes a design method of transformer in high-speed EMU. And it is easy to design by using the analysis model in design the transformer through the establishment of the magnetic analysis model.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.19 no.40
• /
• pp.1-14
• /
• 1996

We develop a dynamic demand forecasting model compared to regression analysis model and AutoRegressive Integrated Moving Average(ARIMA) model. The dynamic model can apply to the current dynamic data to forecasts through introducing state equation. A multiple regression model and ARIMA model using given data are designed via the model analysis. The forecasting fitness evaluation between the designed models and the dynamic model is compared with the criterion of sum of squared error.

• The Journal of the Society of Korean Medicine Diagnostics
• /
• v.15 no.2
• /
• pp.159-168
• /
• 2011

Objectives: The purpose of this study is to develop the pulse wave analysis model with the palpation pressure and the skin effect. Methods: The position of pulse diagnosis was modeled with elastic string system. The skin was modeled with the elastic string, the palpation pressure with tension in the string, and the blood vessel pressure with external force on the string. Using the wave equation in the physics, the simplified pulse model was transformed to the mathematical model. Results: To the verification of the model, the effects of the palpation pressure and the skin effect were tested. Conclusions: There was optimal palpation pressure, describing the exact vessel pressure pattern and maximizing the amplitude of the skin displacement. For the optimal condition, the increased palpation pressure was needed with the increased skin thickness. Therefore, the developed pulse wave analysis model showed the good results.

• Korean Journal of Hydrosciences
• /
• v.10
• /
• pp.17-34
• /
• 1999

The SSARR model adopting Is(integrated snowband) watershed model is applied to Nakdong River basin for lowflow analysis. The IS watershed model is added to new version of the SSARR which has functions of simulating evapotranspiration, infiltration and lower zone routing. It provieds annual water budget informations as an output file and can be operated by interactive mode. Sensitivity analysis for both cases of high and lowflows was carried out, which becomes the knowledge base for model calibration. Model verification was performed using the relative errors of highflows and absolute errors of lowflows at the control points. Monthly water budget analysis was done by IS watershed model, and is reveals that runoff coefficient is 52.6%.

• Korean Journal of Construction Engineering and Management
• /
• v.5 no.4 s.20
• /
• pp.79-86
• /
• 2004

One of the most difficult tasks in pavement management information systems is establishing the links between performance measures of a structure and the design and construction inputs. In-situ pavement performance can be considered a response variable to many project input variables, such as design, construction, and traffic loading effects. If we are to fully understand the component of pavement performance and specify the inputs through design and construction specifications to achieve that performance we must develop quantitative relationship between input and response variables through a scientific, fully integrated Pavement Performance Analysis System (PPAS). Hence, the objective of this study is to design a database model required for developing an effective database template that will allow analysis of pavement performance measures based on design and construction information linked by location. In order to select the most appropriate database model, a conceptual database model (Entity Relationship Model) and dimensional model, which is believed to be the most effective modeling technique for data warehouse project, are designed and compared. It is believed that other state highway agencies could adopt the proposed design strategy for implementing a PPAS at the discretion of the state highway agencies.