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1.
AbstractModel order reduction is a common practice to reduce large order systems so that their simulation and control become easy. Nonlinearity aware trajectory piecewise linear is a variation of trajectory piecewise linearization technique of order reduction that is used to reduce nonlinear systems. With this scheme, the reduced approximation of the system is generated by weighted sum of the linearized and reduced sub-models obtained at certain linearization points on the system trajectory. This scheme uses dynamically inspired weight assignment that makes the approximation nonlinearity aware. Just as weight assignment, the process of linearization points selection is also important for generating faithful approximations. This article uses a global maximum error controller based linearization points selection scheme according to which a state is chosen as a linearization point if the error between a current reduced model and the full order nonlinear system reaches a maximum value. A combination that not only selects linearization points based on an error controller but also assigns dynamic inspired weights is shown in this article. The proposed scheme generates approximations with higher accuracies. This is demonstrated by applying the proposed method to some benchmark nonlinear circuits including RC ladder network and inverter chain circuit and comparing the results with the conventional schemes. 相似文献
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Jun-Bin Ko Sung Wook Lee Dong Eun Kim Young Un Kim Gang Li Seung Goo Lee Tae-Sun Chang Dojin Kim Yong Lak Joo 《Journal of Porous Materials》2006,13(3):325-330
(1 − x)SiO2-(x)ZrO2 (x = 0.1, 0.2) composite fiber mats were prepared by electrospinning their sol-gel precursors of zirconium acetate and tetraethyl
orthosilicate (TEOS) without using a polymer binder. The electrospun composite fibers were characterized by powder X-ray diffraction
(XRD), scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FT-IR) and mercury porosimetry. The composite
fibers having a tetragonal crystalline ZrO2 were obtained by calcining the electrospun composite fibers at high temperatures. The results show that the structure and
crystallization of ZrO2 in the composite fibers can be controlled by sintering temperature, while the porosity and morphology of the fiber mats did
not depend on the sintering temperature. 相似文献
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In financial service industry, service improvement should be considered from process viewpoint and customer viewpoint because the value creation is ultimately linked with internal business processes on the back office and customers are involved as a co-producer of value. In this perspective, customer complaints through call centers are adequate to support the analysis for service improvement in financial service industry. In this study, we propose a web-based decision support system for business process management employing customer complaints, namely Voice of the Customer (VOC), and its handling data for service improvement. It involves VOC conversion for data enrichment and includes analysis of summarization, exception and comparison. The proposed system is evaluated on a major credit card company in South Korea. 相似文献
7.
Dae-Woon Jeong Hyun-Suk Na Jae-Oh Shim Won-Jun Jang Hyun-Seog Roh Un Ho Jung Wang Lai Yoon 《International Journal of Hydrogen Energy》2014
Low temperature water–gas shift (WGS) reaction has been carried out at the gas hourly space velocity of 72,152 h−1 over Cu–CeO2 catalyst prepared by a co-precipitation method. Cu loading was optimized to obtain highly active co-precipitated Cu–CeO2 catalysts for low temperature WGS. 80 wt% Cu–CeO2 exhibited the highest CO conversion as well as the most stable activity (XCO > 46% at 240 °C for 100 h). The excellent catalytic performance is mainly due to a strong metal to support interaction, resulting in the prevention of Cu sintering. 相似文献
8.
Chung Sub Kim Oh Wook Kwon Sun Yeou Kim Sang Un Choi Ki Hyun Kim Kang Ro Lee 《Lipids》2014,49(11):1151-1159
In the course of our continuing search for bioactive constituents of Korean medicinal plants, we isolated five new oxylipins, chaenomic acid A–E ( 1 – 5 ), and six known ones ( 6 – 11 ) from the twigs of Chaenomeles sinensis. The structures of the new compounds ( 1 – 5 ) were determined by spectroscopic methods, including 1D and 2D NMR (1H and 13C NMR, 1H–1H COSY, HMQC, HMBC, and NOESY), olefin cross‐metathesis, and LC/MS analysis. The known compounds ( 6 – 11 ) were identified by comparison of their spectroscopic data and specific optical rotation with the reported data. The isolated compounds ( 1 – 11 ) were tested for their inhibitory effects on nitric oxide production in lipopolysaccharide‐activated murine microglial cells and for their cytotoxic activities against four human cancer cell lines (A549, SK‐OV‐3, A498, and HCT‐15). 相似文献
9.
Accurate measurements have been made to determine radiation transmission of concretes produced with barite, colemanite and normal aggregate by using beam transmission method for 0.663 MeV γ-rays energy of 137Cs radioactive isotopes by using NaI(Tl) scintillation detector. Linear and mass attenuation coefficients of thirteen heavy- and four normal-weight concretes were calculated. It was determined that the linear attenuation coefficient (μ, cm−1) decreased with colemanite concentration and increased with barite concentration in both type of the concretes. Mass attenuation coefficient values of our concretes were compared with the values proposed by the United States National Institute of Standards and Technology (NIST). 相似文献
10.
The cross-sectional distortion usually appears during rotary-draw bending process of thin-walled rectangular tube with small bending radius.To study the cross-sectional distortion of the tube,a three-dimensional finite-element model of the process was developed based on ABAQUS/Explicit code and its reliability was validated by experiment.Then,the cross-sectional distortion behaviors of the tube were investigated.The results show that a zone of larger circumferential stress appears on the tube when bending angle reaches 30°.And in the larger circumferential stress zone,the sagging phenomenon is produced obviously.The maximum cross-sectional distortion is located in the larger circumferential stress zone and the angle between the plane of maximum cross-sectional distortion and the bending reference plane is about 50°.The position of the maximum cross-sectional distortion keeps almost unchanged with the variation of the clearances between dies and tube. 相似文献