1,721,431 research outputs found
Non-uniformly sampled mosaic construction using resolution map
No full textA new type of mosaic is suggested: a non-uniformly sampled mosaic to minimise the loss of image data occurring by coordinate transformations. A resolution map is introduced in order to measure the spatially variant number of samples. By using an appropriate method of blending and interpolation, we construct a non-uniformly sampled mosaic. Simulation results show an increase in the image quality of the frames reconstructed from the non-uniformly sampled mosaic
An ultraprecision stage for alignment of wafers in advanced microlithography
No full textWe present an ultraprecision stage specially designed to align wafers for the microlithography of integrated circuit patterns of sub-0.3 mu m design rules. The whole stage mechanism is composed of two individually operating xy theta-stages: a global stage to provide initial coarse alignment of wafers in stepping mode; and a micro stage to produce fine controlability in nanometer range. The global stage is configured with three linear motors kinematically linked to produce xy theta-motions without resorting to precision guideways. The micro stage corrects positional errors in the global stage by activating three piezoelectric microactuators housed in an elastic flexure. These two stages are simultaneously controlled as a dual servo system, because the main emphasis is given to achieving an overall positioning reproducibility of 20 nanometers in xy theta-motions in aligning wafers of 200-mm size. (C) 1997 Elsevier Science Inc
A Flexible Preprocessing System for NASTRAN: Neutral Geometric Data Base Approach to Integrated CAD
No full text
Complex time series modeling and analysis for rotor dynamics identification
No full textA new time series method, directional ARMAX (dARMAX) model-based approach, is proposed for rotor dynamics identification. The dARMAX processes complex-varied signals, utilizing the complex modal resting theory which enables the separation of the backward and forward modes in the two-sided frequency domain and makes effective modal parameter identification possible, to account for the dynamic characteristics inherent in rotating machinery. The dARMAX is superior in nature to the conventional ARMAX particularly in the estimation of the modal parameters for isotropic and weakly anisotropic rotors. Numerical simulations are performed to demonstrate effectiveness of the dARMAX
Piecewise regression for fuzzy input-output data with automatic change-point detection by quadratic programming
No full text[[abstract]]To handle the large variation issues in fuzzy input-output data, the proposed quadratic programming (QP) method uses a piecewise approach to simultaneously generate the possibility and necessity models, as well as the change-points. According to Tanaka and Lee [ H. Tanaka, H. Lee, Interval regression analysis by quadratic programming approach, IEEE Transactions on Fuzzy Systems 6 ( 1998) 473-481], the QP approach gives more diversely spread coefficients than linear programming ( LP) does. However, their approach only deals with crisp input and fuzzy output data. Moreover, their method is weak in handling fluctuating data. So far, no method has been developed to cope with the large variation problems in fuzzy input-output data. Hence, we propose a piecewise regression for fuzzy input-output data with a QP approach. There are three advantages in our method. First, the QP technique gives a more diversely spread coefficient than does a linear programming technique. Second, the piecewise approach is used to detect the change-points in the estimated model automatically, and handle the large variation data such as outliers well. Third, the possibility and necessity models with better fitness in data processing are obtained at the same time. Two examples are presented to demonstrate the merits of the proposed method. (C) 2009 Elsevier B. V. All rights reserved.[[note]]SC
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