نتایج جستجو برای: adaptive filtering

تعداد نتایج: 259590  

2002
Shinsuke Takaoka Fumiyuki Adachi

Adaptive prediction iterative channel estimation is presented for combined antenna diversity and coherent rake reception of direct sequence spread spectrum (DSSS) signals. Its first stage uses pilot-aided adaptive prediction channel estimation, while the succeeding iteration stages use decision feedback and moving average filtering for channel re-estimation. The bit error rate (BER) performance...

2002
Andrei Anghelescu Endre Boros David D. Lewis Vladimir Menkov David J. Neu Paul B. Kantor

This year at TREC 2002 we participated in the adaptive filtering sub-task of the filtering track with some models for training a Rocchio classifier. Results were poorer than average on the utility type measures. Using simple feature selection produced better than average results on an F-type measure. The key to our approach was the use of pseudojudgments, and an approach to threshold updating. ...

2013
Mikhail Erekhinsky Ivan K. Schuller

The magnetoresistance of Ni/V2O3/Py devices shows interesting behavior in the temperature dependence across the V2O3 metal-insulator transition. A spin-valve effect ( 0.1%) is found below the transition temperature when V2O3 is in the insulating phase. Contrary to expectation, the spin-valve effect disappears when device is heated above 150 K and V2O3 is in the metallic state. At these temperat...

2004
J. M. de Haan

Subband adaptive filters have been proposed to circumvent the drawbacks of slow convergence and high computational complexity associated with time domain adaptive filters. Subband processing introduces transmission delays and signal degradations due to aliasing effects. In order to overcome the transmission delays, delayless adaptive filtering has been introduced where the coefficient adaptatio...

2005
Gert Schoonenberg Marc Schrijver Qi Duan Richard Kemkers Andrew Laine

Adaptive filtering of temporally varying X-ray image sequences acquired during endovascular interventions can improve the visual tracking of catheters by radiologists. Existing techniques blur the important parts of image sequences, such as catheter tips, anatomical structures and organs; and they may introduce trailing artifacts. To address this concern, an adaptive filtering process is presen...

2013
Ryan J. Tibshirani

We study trend filtering, a recently proposed tool of Kim et al. (2009) for nonparametric regression. The trend filtering estimate is defined as the minimizer of a penalized least squares criterion, in which the penalty term sums the absolute kth order discrete derivatives over the input points. Perhaps not surprisingly, trend filtering estimates appear to have the structure of kth degree splin...

2017
Weiwei Lyu Xianghong Cheng

Transfer alignment is always a key technology in a strapdown inertial navigation system (SINS) because of its rapidity and accuracy. In this paper a transfer alignment model is established, which contains the SINS error model and the measurement model. The time delay in the process of transfer alignment is analyzed, and an H∞ filtering method with delay compensation is presented. Then the H∞ fi...

Journal: :Journal of magnetic resonance imaging : JMRI 2001
C F Westin L Wigström T Loock L Sjöqvist R Kikinis H Knutsson

In order to enhance 3D image data from magnetic resonance angiography (MRA), a novel method based on the theory of multidimensional adaptive filtering has been developed. The purpose of the technique is to suppress image noise while enhancing important structures. The method is based on local structure estimation using six 3D orientation selective filters, followed by an adaptive filtering step...

Journal: :Vision Research 1997
Steven C. Dakin

Experiments are reported which examine the judgement of the mean orientation of textures composed either of short lines or dipoles (Glass patterns). The effects of element length, density, and orientation variation are described. Psychophysical data are compared with predictions from four schemes for extracting features from Glass patterns: token matching, isotropic filtering, oriented filterin...

2009
N. Praveen Kumar Abhijit Mitra Cemal Ardil

Decision feedback equalizers are commonly employed to reduce the error caused by intersymbol interference. Here, an adaptive decision feedback equalizer is presented with a new adaptation algorithm. The algorithm follows a block-based approach of normalized least mean square (NLMS) algorithm with set-membership filtering and achieves a significantly less computational complexity over its conven...

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