• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.34 no.8
• /
• pp.989-996
• /
• 2010

Statistical regression and/or interpolation models have been used for data analysis and response prediction using the results of the physical experiments and/or computer simulations in structural engineering fields. These models have been employed during the last decade to develop a variety of design methodologies. However, these models only handled responses with respect to space variables such as size and shape of structures and cannot handle time-variant dynamic responses, i.e. response varying with time. In this research, statistical space-time metamodels based on multiple response approach that can handle responses with respect to both space variables and a time variable are proposed. Regression and interpolation models such as the response surface model (RSM) and kriging model were developed for handling time-variant dynamic responses of structural engineering. We evaluate the accuracies of the responses predicted by the two statistical space-time metamodels by comparing them with the responses obtained by the physical experiments and/or computer simulations.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.36 no.8
• /
• pp.873-879
• /
• 2012

Metamodels have been developed with a variety of design optimization techniques in the field of structural engineering over the last decade because they are efficient, show excellent prediction performance, and provide easy interconnections into design frameworks. To construct a metamodel, a sequential procedure involving steps such as the design of experiments, metamodeling techniques, and validation techniques is performed. Because validation techniques can measure the accuracy of the metamodel, the number of presampled points for an accurate kriging metamodel is decided by the validation technique in the sequential kriging metamodel. Because the interpolation model such as the kriging metamodel based on computer experiments passes through responses at presampled points, additional analyses or reconstructions of the metamodels are required to measure the accuracy of the metamodel if existing validation techniques are applied. In this study, we suggest a sensitivity validation that does not require additional analyses or reconstructions of the metamodels. Fourteen two-dimensional mathematical problems and an engineering problem are illustrated to show the feasibility of the suggested method.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.16 no.6
• /
• pp.1291-1299
• /
• 2012

UML is a semantically rich language, but it is difficult to ensure consistency of the diagrams you have written. Therefore, in this paper, we propose cross checking rules to improve consistency between UML diagrams, especially between UML static diagram and dynamic diagram. We use metamodels in order to more clearly reflect interactions of UML elements in the checking rules and use OCL(Object Constraint Language) to accurately represent the checking rules. By comparing with the well-formedness rules of UML specification, we focus on consistency of UML diagrams. And we derive metamodels of static diagram and dynamic diagram, analysis the relationships of UML diagrams and finally, we test the usability of derived rules through a case study.

• Structural Engineering and Mechanics
• /
• v.67 no.3
• /
• pp.301-310
• /
• 2018

In this paper, a multi-objective multiparameter optimization procedure is developed by combining rigorously developed metamodels with an evolutionary search algorithm-Genetic Algorithm (GA). Response surface methodology (RSM) is used for developing the metamodels to replace the tedious finite element analyses. A nine-node isoparametric plate bending element is used for conducting the finite element simulations. Highly accurate numerical data from an author compiled FORTRAN finite element program is first used by the RSM to develop second-order mathematical relations. Four material parameters-${\frac{E_1}{E_2}}$, ${\frac{G_{12}}{E_2}}$, ${\frac{G_{23}}{E_2}}$ and ${\upsilon}_{12}$ are considered as the independent variables while simultaneously maximizing fundamental frequency, ${\lambda}_1$ and frequency separation between the $1^{st}$ two natural modes, ${\lambda}_{21}$. The optimal material combination for maximizing ${\lambda}_1$ and ${\lambda}_{21}$ is predicted by using a multi-objective GA. A general sensitivity analysis is conducted to understand the effect of each parameter on the desired response parameters.

• Computers and Concrete
• /
• v.18 no.6
• /
• pp.1065-1082
• /
• 2016

The main aim of this study is to predict the compressive and flexural strengths of self-compacting mortar (SCM) containing $nano-SiO_2$, $nano-Fe_2O_3$ and nano-CuO using wavelet-based weighted least squares-support vector machines (WLS-SVM) approach which is called WWLS-SVM. The WWLS-SVM regression model is a relatively new metamodel has been successfully introduced as an excellent machine learning algorithm to engineering problems and has yielded encouraging results. In order to achieve the aim of this study, first, the WLS-SVM and WWLS-SVM models are developed based on a database. In the database, nine variables which consist of cement, sand, NS, NF, NC, superplasticizer dosage, slump flow diameter and V-funnel flow time are considered as the input parameters of the models. The compressive and flexural strengths of SCM are also chosen as the output parameters of the models. Finally, a statistical analysis is performed to demonstrate the generality performance of the models for predicting the compressive and flexural strengths. The numerical results show that both of these metamodels have good performance in the desirable accuracy and applicability. Furthermore, by adopting these predicting metamodels, the considerable cost and time-consuming laboratory tests can be eliminated.

• The KIPS Transactions:PartD
• /
• v.10D no.6
• /
• pp.971-982
• /
• 2003

The consistency of UML diagrams is a nature for checking whether diagrams are coherently designed with only one requirements and the correctness of UML Diagrams, especially it uses OCL(Object Constraint Language) which is standard constraint language in UML. Firstly we devise metamodels that are described with conponent and relationships, then we derive verification rules from each matamodels for verifying correctness and consistency, and then we formally specify the rules with OCL for automatic verification. Finally we verify the rules with USE TOOL.

• Journal of the Korea Society for Simulation
• /
• v.16 no.2
• /
• pp.45-54
• /
• 2007

In this article, we propose a different modeling approach, which aims at the simulation optimization so as to meet the design specification. Generally, Multi objective optimization problem is formulated by dependent factors as objective functions and independent factors as constraints. However, this paper presents the critical(dependent) factors as objective function and design(independent) factors as constraints for the selection of design factors directly. The objective function is normalized far the generalization of design factors while the constraints are composed of the simulation-based regression metamodels fer the critical factors and design factor's domain. Then the effective and fast solution procedure based on the pareto optimal solution set is proposed. This paper provides a comprehensive framework for the system design using the simulation and metamodels. Therefore, the method developed for this research can be adopted for other enhancements in different but comparable situations.

• The KIPS Transactions:PartD
• /
• v.16D no.3
• /
• pp.381-394
• /
• 2009

As a technique to enhance reusability for the created artifacts in software modeling process, the model driven method such like MDA has been applied. Unfortunately, the hierarchical and systematic MDA based development technique using UML is poor yet. This causes the problem that the MDA modeling with high consistency and reusability based on MDA metamodel is not being realized. To solve this problem, this paper proposes a MDA (PIM/PSM) component modeling technique using 2+1 view integrated metamodel. At first, the meta-architecture view model which can represents development process view and MVC view is defined. Then, the hierarchical integrated metamodels per view are addressed separately for modeling process and MVC at metamodel level on the hierarchy of the defined meta-architecture view model. These metamodels are defined hierarchically by layering the modeling elements in PIM and PSM pattern for UML models and GUI models. Appling the proposed metamodel to an ISMS application system, it is shown as a component modeling case study based on MDA. Through this approach, we are able to perform a component model with consistency and hierarchy corresponding to development process and MVC way. Accordingly, this may improve more independence and reusability of model.

• Journal of KIISE:Software and Applications
• /
• v.30 no.12
• /
• pp.1158-1171
• /
• 2003

The UML is a widely accepted standard in object-oriented modeling. As the UML is semantically rich, we can describe in detail the system that will be developed, but we cannot guarantee the correctness and consistency of the designed model. Therefore, it is important to minimize the error by verifying user models in an early stage. In this paper, we propose a method for verifying the consistency of UML structural diagrams and behavioral diagrams using OCL verification rules and meta-metamodel. The consistency is a nature for checking whether the structural diagrams and behavioral diagrams are coherently designed according to a specific requirement. First we build meta-metamodels of the structural diagram and behavioral diagram that are described with the UML diagrams and the related elements, we derive rules for verifying the consistency from each meta-metamodels, and then formally specify with the language such as OCL for automatic verification. Finally, we verify the usefulness of the rule through a case study.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.19 no.5
• /
• pp.975-982
• /
• 2024

This paper optimally designs the shape of the rotor notch to improve the efficiency and reduce torque ripple of a 30kW EV traction IPMSM. To improve torque ripple, notches were applied to the IPMSM rotor and the optimal design was performed. Elliptical, square, and triangular notches were applied to the IPMSM rotor and sample points of the IPMSM were generated within the specified design range using OLHD. Fifty sample points were generated for each of the three types of notches, and five metamodels were generated. The model with the lowest RMSE among the generated metamodels was selected, and parameter sensitivity analysis and optimal design were performed using this. The results of the optimal design were verified by FEA and compared with the torque characteristics of the existing IPMSM. As a result, the torque ripple was reduced by 62.5% to 1.376Nm compared to the initial model, the peak-to-peak cogging torque was reduced by 34% to 0.547Nm, and the efficiency was 96.742%.