• Korean Journal of Computational Design and Engineering
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• v.15 no.3
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• pp.243-252
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• 2010

This paper describes a new practical simplification method for feature-based solid models. In this approach, a solid model created using feature modeling operations is first simplified by the suppression of detailed features, and then, if necessary, the model is converted to a surface model to facilitate its modification. Finally, the simplified surface model is delivered to analysis packages. The algorithm was implemented based on CATIA V.5 and applied to mid-surface generation of plastic parts for structural analysis to prove the validity and usefulness.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.31 no.8
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• pp.33-38
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• 1982

This paper deals with the simplification of the transfer function in a frequency domain, viz. the integral of the squared errors between the original and the simplified model is minimized and the latter is estimated by the Walsh function. It tries to minimize the errors between the frequency responses of the two functions. This method is compared with the existing method by means of a numercal example. The frequency response of this simplified model approximates closely to that of the original model. The proposed method is simpler in analysis and easier in implementation than the existing methods. Though the Walsh function can be easily generated with the discrete values, it has errors because its zero crossings are not continuous. This method aims at the reduction of the errors in the real parts and the imaginary parts of the two functions by dividing into the more sub-intervals, and selecting the reduced-order model according to the response of the model. As a result, it can be applied for the simplification of higher order functions into lower order functions and for the design of control systems.

• Nuclear Engineering and Technology
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• v.51 no.5
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• pp.1333-1344
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• 2019

An integrated approach of model simplification for high burnup spent nuclear fuel is proposed based on material calibration using optimization. The spent fuel rods are simplified into a beam with a homogenous isotropic material. The proposed approach of model simplification is applied to fuel rods with two kinds of interfacial configurations between the fuel pellets and cladding. The differences among the generated models and the effects of interfacial bonding efficiency are discussed. The strategy of model simplification adopted in this work is to force the simplified beam model of spent fuel rods to possess the same compliance and failure characteristics under critical loads as those that result in the failure of detailed fuel rod models. It is envisioned that the simplified model would enable the assessment of fuel rod failure through an assembly-level analysis, without resorting to a refined model for an individual fuel rod. The effective material properties of the simplified beam model were successfully identified using the integrated optimization process. The feasibility of using the developed simplified beam models in dynamic impact simulations for a horizontal drop condition is examined, and discussions are provided.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.42 no.6
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• pp.141-148
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• 2005

Simplification of 3D models is becoming necessary with popularity of 3D graphics over mobile or the internet channels with limited channel capacity. Surfaces of a 3D model are usually approximated by a series of triangular meshes, and vertex contraction method is employed widely to minimize the deviation from the original model. Determination of the best position after contraction depends on the calculation of simplification error. We propose a new measure for computing the error so that the simplified model represents the original faithfully. We demonstrate the improved results with real 3D models.

• Journal of Korean Society of Water and Wastewater
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• v.21 no.4
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• pp.409-420
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• 2007

ASM No. 1 is a very useful model to analyze wastewater treatment system removing organic carbon and nitrogen material. But it isn't adequate to control the wastewater treatment system with real time since it has many material divisions and parameters. So, the purpose of this study is the simplification of ASM No. 1 to control the wastewater treatment system. ASM No. 1 was changed with the model which has 3 material divisions(COD, $NH_4{^+}$, $NO_3{^-}$) and two phases(Aerobic and Anoxic condition). SBR was running with two phases(Phase I and II). Phase II running 20 minutes with aerobic time was used for deciding model parameters and Phase I running 12 minutes with aerobic time was used for proving the simplified model. The simplified model was compared with ASM No. 1 using data of Phase I and II. As a result of model comparison, the simplified model has enough ability to express the variation of $NH_4{^+}$ compound.

• Journal of Korea Water Resources Association
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• v.52 no.8
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• pp.531-543
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• 2019

Constructing a reliable runoff model and reducing model runtime are important in research of real-time urban flood forecasting to reduce the repetitive flood damage. Sewer networks in the major urban basin such as Seoul are vast and complex so that it is not suitable for real-time urban flood forecasting. Therefore, the rainfall-runoff model should be simplified. However, the runoff results due to the simplification of sewer networks can vary depending on the subjectivity and simplification method of the researcher and there is a significant difference especially in 2-D inundation analysis. In this study, the sewer networks in various urban basins with different numbers and distributions of sewer networks were simplified to certain criteria. The accuracy of the simplification model according to the sewer network scale is evaluated by 2-D inundation analysis. The runoff models of Gwanak, Sillim, and Dorimcheon, frequently inundated basins were simplified based on four simplification ranges due to the cumulative drainage area set as a criterion for calculating the simplification range. This study will be expected that the inundation result of simplification models estimated through the analysis can contribute to the construction of a reasonable and accurate runoff model suitable for real-time flood forecasting.

• ETRI Journal
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• v.34 no.5
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• pp.791-794
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• 2012

We propose an efficient framework to realistically render 3D faces with a reduced set of points. First, a robust active appearance model is presented to detect facial features in the projected faces under different illumination conditions. Then, an adaptive simplification of 3D faces is proposed to reduce the number of points, yet preserve the detected facial features. Finally, the point model is rendered directly, without such additional processing as parameterization of skin texture. This fully automatic framework is very effective in rendering massive facial data on mobile devices.

• The Journal of the Korea Contents Association
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• v.3 no.4
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• pp.69-76
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• 2003

Recently, in computer graphics, researches on 3D animations have been very active. one of the important research areas in 3D animation is animation of human being. The creation and animation of 3D facial models has depended on animators' manual work frame by frame. Thus, it needs many efforts and time as well as various hardwares and softwares. In this paper, we implements a way to generation 3D human face model easily and quickly just with the front face images. Then, we suggests a methodology for mesh data simplification of 3D generic model.

• Journal of Institute of Control, Robotics and Systems
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• v.6 no.5
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• pp.339-344
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• 2000

This paper is concerned with the simplification of complex linear time-invariant systems. A simple technique is suggested using the well-known least squares method in the frequency domain. Given a high-order transfer function in the s- or z-domain, the squared-gain function corresponding to a low-order model is computed by the least squares method. Then, the low-order transfer function is obtained through the factorization. Three examples are given to illustrate the efficiency of the proposed method.

• 제어로봇시스템학회:학술대회논문집
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• 1986.10a
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• pp.65-67
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• 1986

The model simplification method of the linear time invariant continuous system is proposed. Using the energy dispersion method the dynamic modes with dominent energy contribution are selected, and the poles of the denomenater are retained. And there is investigated how the dynamic modes affected the system characteristic. The parameters of the numerator are determined by time moment matching method. This method is that the algorithm is simple and also the simplified model found is always stable if the original system is stable, and through examples we assured that this method leads to good results in both transient and steady state responses.