Authors:
Yuexian Zou, Department of Electrical and Electronic Engineering, The University of Hong Kong (Hong Kong)
S.C. Chan, Department of Electrical and Electronic Engineering, The University of Hong Kong (Hong Kong)
T.S. Ng, Department of Electrical and Electronic Engineering, The University of Hong Kong (Hong Kong)
Page (NA) Paper number 1948
Abstract:
In this paper, a robust M-estimate adaptive filter for impulse noise
suppression is proposed. The objective function used is based on a
robust M-estimate. It has the ability to ignore or down weight large
signal error when certain thresholds are exceeded. A systematic method
for estimating such thresholds for adaptation is also proposed. An
advantage of the proposed method is that its solution is governed by
a system of linear equation. Therefore, fast adaptation algorithms
for traditional linear adaptive filters can be applied. In particular,
a M-estimate recursive least square (M-RLS) adaptive algorithm is studied
in detail. Simulation results show that it is more robust against individual
and consecutive impulse noise than the MN-LMS [2] and the N-RLS algorithms
[7]. It also has fast convergence speed and a low steady state error
similar to its RLS counterpart.
Authors:
Hakan Öktem, Tampere University of Technology Signal Processing Laboratory Finland (Finland)
Karen O Egiazarian, Tampere University of Technology Signal Processing Laboratory Finland (Finland)
Juha Nousiainen, Tampere University of Technology Ragnar Granit Institute Finland (Finland)
Page (NA) Paper number 1676
Abstract:
There are various de-noising algorithms and optimization methods for
different signal and noise characteristics. However, the signals used
in real application may have deviations from the model. For example:
signal and/or noise may not be stationary or a proper model for them
may not be available. MCG (magnetocardiography) is an example signal,
where conventional de-noising methods are not giving satisfactory results.
Local adaptive processing allow to modify filtering parameters according
to the specific properties of different 'portions' of a signal. In
this paper a methodology for adopting the transform domain local adaptive
processing to the specific task of MCG signal de-noising is introduced.
Authors:
Hamid Krim,
Yufang Bao, ECE Dept., NCSU, Raleigh NC 27695-7914 and BUPT, P.R. China (China)
Page (NA) Paper number 2195
Abstract:
We present a stochastic formulation of a linear diffusion equation
(or heat equation), and in light of the potential applications ranging
from signal denoising to image enhancement/segmentation of its nonlinear
extensions, we propose a more general nonlinear stochastic diffusion.
The constructed stochastic framework, in contrast to traditional deterministic
approaches, unveils the sources of of existing limitations and allows
us to further significantly improve the performance by addressing the
key problem. Substantiating examples are provided.
Authors:
Petre Stoica, Systems and Control Group, Uppsala University, Uppsala, Sweden. (Sweden)
Hongbin Li, Department of Electrical and Computer Engineering,University of Florida, Gainesville, Florida, USA. (USA)
Jian Li, Department of Electrical and Computer Engineering,University of Florida, Gainesville, Florida, USA. (USA)
Page (NA) Paper number 1016
Abstract:
We investigate herein the problem of amplitude estimation of sinusoidal
signals from observations corrupted by colored noise. A relatively
large number of amplitude estimators are described which encompass
Least Squares (LS) and Weighted Least Squares (WLS) methods. Additionally,
filterbank approaches, which are widely used for spectral analysis,
are extended to amplitude estimation. Specifically, we consider the
recently introduced MAtched-FIlterbank (MAFI) approach and show that,
by appropriately designing the prefilters, the MAFI approach includes
the WLS approach. The amplitude estimation techniques discussed in
this paper do not model the noise, and yet they are all asymptotically
statistically efficient. It is their different finite-sample properties
that are of particular interest to this study. Numerical examples are
provided to illustrate the differences among the various estimators.
Though amplitude estimation applications are numerous, we focus on
system identification using sinusoidal probing signals.
Authors:
Channarong Tontiruttananon,
Jitendra K Tugnait,
Page (NA) Paper number 1321
Abstract:
The problem of closed loop system identification given noisy time-domain
input-output measurements is considered. It is assumed that the various
disturbances affecting the system are zero-mean stationary whereas
the closed loop system operates under an external cyclostationary input
which is not measured. Noisy measurements of the (direct) input and
output of the plant are assumed to be available. The closed loop system
must be stable but it is allowed to be unstable in open loop. Recently
we proposed two identification algorithms using cyclic-spectral analysis
of noisy input-output data. In this paper we provide an asymptotic
performance analysis of the recently proposed parameter estimators.
Computer simulation examples are presented in support of the analysis.
Authors:
Takashi Kimura,
Hideaki Sasaki,
Hiroshi Ochi, Faculty of Eng., Univ. of the Ryukyus (U.K.)
Page (NA) Paper number 1409
Abstract:
In this paper, we show a new blind identification algorithm which is
based on second order statistics and exploits a Single-Input Double-Output(SIDO)
model. It is suitable for a real-time processing system because of
lower operation and high-speed convergence. The proposed blind identification
algorithm is superior to conventional algorithms in view of simple
structure and the uniqueness of solution. We also verify its efficiency
by computer simulation.
Authors:
Gopal T Venkatesan,
Lang Tong,
Mostafa Kaveh,
Ahmed H Tewfik,
Kevin M Buckley,
Page (NA) Paper number 1040
Abstract:
In this paper we present a method for the deterministic blind identification
of single-input multiple-output systems with unknown model order. The
technique, that is applicable to both the FIR and IIR cases, requires
only an upper bound of the model order. It is based on the special
kernel structure of block Toeplitz matrices. When the model order is
overestimated, this special structure entails the true solution to
be embedded in the overestimated solution in a unique shift-chain form.
This special shift-chain structure is then utilized to extract the
true solution.
Authors:
Rafael Ruiz,
Margarita Cabrera,
Page (NA) Paper number 1251
Abstract:
This paper addresses the problems of blind channel estimation and symbol
detection with second order statistics methods from the received data.
It can be shown that this problem is similar to Direction Of Arrival
(DOA) estimation, where many solutions like the MUSIC algorithm or
"weighted" techniques (as Deterministic Maximum Likelihood or Weighted
Subspace Fitting method) have been developed. In this proposal we extend
these techniques to blind channel identification problem in an unified
framework known as Subspace Fitting. In this framework the estimated
and the received data are "fitting" through the subspaces in a least
square sense. Then, in order to solve this problem and estimate the
channel, a modified Gauss-Newton type algorithm is suggested. Simulations
are carried out comparing the proposed solutions with a classical signal
subspace-based blind channel identification scheme.
Authors:
Carlos Avendano,
Jacob Benesty,
Dennis R Morgan,
Page (NA) Paper number 1741
Abstract:
We describe a new method for blind system identification that uses
the cross relation properties between two or more sensor signals to
estimate the impulse responses of the channels. The method performs
as well or better than other similar blind identification techniques
under noisy and ill-conditioned channel conditions, and is computationally
simpler to implement.
Authors:
Konstantinos I Diamantaras, Dept. of Informatics, Technological Education Institute, GR-54101 Sindos, Greece (Greece)
Athina P Petropulu,
Page (NA) Paper number 2407
Abstract:
The blind estimation of mixing channels resulting from frequency selective
fading and multipath in a multi-user CDMA system is an important problem
in wireless communications. We present a novel frequency-domain approach
using second order spectral statistics for recovering the unknown channels.
Unlike other methods which are based on time-domain analysis we make
no particular assumption about the support of the mixing channels except
that they have finite length (FIR). The method is based on the fact
that the source sequences obtain a known spectral color derived from
the corresponding spreading code used in CDMA.
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