**Commenced**in January 2007

**Frequency:**Monthly

**Edition:**International

**Paper Count:**398

# Search results for: signal approximation

##### 398 Cooperative Sensing for Wireless Sensor Networks

**Authors:**
Julien Romieux,
Fabio Verdicchio

**Abstract:**

**Keywords:**
Cooperative signal processing,
power management,
signal representation,
signal approximation,
wireless sensor
networks.

##### 397 Best Co-approximation and Best Simultaneous Co-approximation in Fuzzy Normed Spaces

**Authors:**
J. Kavikumar,
N. S. Manian,
M.B.K. Moorthy

**Abstract:**

The main purpose of this paper is to consider the t-best co-approximation and t-best simultaneous co-approximation in fuzzy normed spaces. We develop the theory of t-best co-approximation and t-best simultaneous co-approximation in quotient spaces. This new concept is employed us to improve various characterisations of t-co-proximinal and t-co-Chebyshev sets.

**Keywords:**
Fuzzy best co-approximation,
fuzzy quotient spaces,
proximinality,
Chebyshevity,
best simultaneous co-approximation.

##### 396 Improved Approximation to the Derivative of a Digital Signal Using Wavelet Transforms for Crosstalk Analysis

**Authors:**
S. P. Kozaitis,
R. L. Kriner

**Abstract:**

**Keywords:**
digital signals,
electronics,
IBIS model,
printedcircuit board,
wavelets

##### 395 Comparison between Beta Wavelets Neural Networks, RBF Neural Networks and Polynomial Approximation for 1D, 2DFunctions Approximation

**Authors:**
Wajdi Bellil,
Chokri Ben Amar,
Adel M. Alimi

**Abstract:**

This paper proposes a comparison between wavelet neural networks (WNN), RBF neural network and polynomial approximation in term of 1-D and 2-D functions approximation. We present a novel wavelet neural network, based on Beta wavelets, for 1-D and 2-D functions approximation. Our purpose is to approximate an unknown function f: Rn - R from scattered samples (xi; y = f(xi)) i=1....n, where first, we have little a priori knowledge on the unknown function f: it lives in some infinite dimensional smooth function space and second the function approximation process is performed iteratively: each new measure on the function (xi; f(xi)) is used to compute a new estimate Ôêºf as an approximation of the function f. Simulation results are demonstrated to validate the generalization ability and efficiency of the proposed Beta wavelet network.

**Keywords:**
Beta wavelets networks,
RBF neural network,
training algorithms,
MSE,
1-D,
2D function approximation.

##### 394 On an Open Problem for Definable Subsets of Covering Approximation Spaces

**Authors:**
Mei He,
Ying Ge,
Jingyu Qian

**Abstract:**

**Keywords:**
Covering approximation space,
covering approximation operator,
definable subset,
inner definable subset,
outer definable subset.

##### 393 Some Separations in Covering Approximation Spaces

**Authors:**
Xun Ge,
Jinjin Li,
Ying Ge

**Abstract:**

**Keywords:**
Rough set,
covering approximation space,
granularitywise separation.

##### 392 A New Method for Contour Approximation Using Basic Ramer Idea

**Authors:**
Ali Abdrhman Ukasha

**Abstract:**

**Keywords:**
Polygonal approximation,
Ramer,
Triangle and
Trapezoid methods.

##### 391 Definable Subsets in Covering Approximation Spaces

**Authors:**
Xun Ge,
Zhaowen Li

**Abstract:**

**Keywords:**
Covering approximation space,
covering approximation operator,
definable subset,
inner definable subset,
outer definable subset.

##### 390 High-Resolution 12-Bit Segmented Capacitor DAC in Successive Approximation ADC

**Authors:**
Wee Leong Son,
Hasmayadi Abdul Majid,
Rohana Musa

**Abstract:**

**Keywords:**
Successive Approximation Register Analog-to-
Digital Converter,
SAR ADC,
Low voltage ADC.

##### 389 Time Delay Estimation Using Signal Envelopes for Synchronisation of Recordings

**Authors:**
Sergei Aleinik,
Mikhail Stolbov

**Abstract:**

In this work, a method of time delay estimation for dual-channel acoustic signals (speech, music, etc.) recorded under reverberant conditions is investigated. Standard methods based on cross-correlation of the signals show poor results in cases involving strong reverberation, large distances between microphones and asynchronous recordings. Under similar conditions, a method based on cross-correlation of temporal envelopes of the signals delivers a delay estimation of acceptable quality. This method and its properties are described and investigated in detail, including its limits of applicability. The method’s optimal parameter estimation and a comparison with other known methods of time delay estimation are also provided.

**Keywords:**
Cross-correlation,
delay estimation,
signal envelope,
signal processing.

##### 388 Target Signal Detection Using MUSIC Spectrum in Noise Environment

**Authors:**
Sangjun Park,
Sangbae Jeong,
Moonsung Han,
Minsoo hahn

**Abstract:**

**Keywords:**
Beamforming,
direction of arrival,
multiple signal
classification,
target signal detection.

##### 387 Implemented 5-bit 125-MS/s Successive Approximation Register ADC on FPGA

**Authors:**
S. Heydarzadeh,
A. Kadivarian,
P. Torkzadeh

**Abstract:**

**Keywords:**
Analog to digital converter,
Successive
approximation,
Capacitor switching algorithm,
FPGA

##### 386 Generalization Kernel for Geopotential Approximation by Harmonic Splines

**Authors:**
Elena Kotevska

**Abstract:**

**Keywords:**
Geopotential,
Reproducing Kernel,
Approximation,
Regular Surface

##### 385 The Inverse Problem of Nonsymmetric Matrices with a Submatrix Constraint and its Approximation

**Authors:**
Yongxin Yuan,
Hao Liu

**Abstract:**

In this paper, we first give the representation of the general solution of the following least-squares problem (LSP): Given matrices X ∈ Rn×p, B ∈ Rp×p and A0 ∈ Rr×r, find a matrix A ∈ Rn×n such that XT AX − B = min, s. t. A([1, r]) = A0, where A([1, r]) is the r×r leading principal submatrix of the matrix A. We then consider a best approximation problem: given an n × n matrix A˜ with A˜([1, r]) = A0, find Aˆ ∈ SE such that A˜ − Aˆ = minA∈SE A˜ − A, where SE is the solution set of LSP. We show that the best approximation solution Aˆ is unique and derive an explicit formula for it. Keyw

**Keywords:**
Inverse problem,
Least-squares solution,
model updating,
Singular value decomposition (SVD),
Optimal approximation.

##### 384 A Numerical Model to Study the Rapid Buffering Approximation near an Open Ca2+ Channel for an Unsteady State Case

**Authors:**
Leena Sharma

**Abstract:**

Chemical reaction and diffusion are important phenomena in quantitative neurobiology and biophysics. The knowledge of the dynamics of calcium Ca^{2+} is very important in cellular physiology because Ca^{2+} binds to many proteins and regulates their activity and interactions Calcium waves propagate inside cells due to a regenerative mechanism known as calcium-induced calcium release. Buffer-mediated calcium diffusion in the cytosol plays a crucial role in the process. A mathematical model has been developed for calcium waves by assuming the buffers are in equilibrium with calcium i.e., the rapid buffering approximation for a one dimensional unsteady state case. This model incorporates important physical and physiological parameters like dissociation rate, diffusion rate, total buffer concentration and influx. The finite difference method has been employed to predict [Ca^{2+}] and buffer concentration time course regardless of the calcium influx. The comparative studies of the effect of the rapid buffered diffusion and kinetic parameters of the model on the concentration time course have been performed.

**Keywords:**
Calcium Profile,
Rapid Buffering Approximation,
Influx,
Dissociation rate constant.

##### 383 Reduction of Linear Time-Invariant Systems Using Routh-Approximation and PSO

**Authors:**
S. Panda,
S. K. Tomar,
R. Prasad,
C. Ardil

**Abstract:**

Order reduction of linear-time invariant systems employing two methods; one using the advantages of Routh approximation and other by an evolutionary technique is presented in this paper. In Routh approximation method the denominator of the reduced order model is obtained using Routh approximation while the numerator of the reduced order model is determined using the indirect approach of retaining the time moments and/or Markov parameters of original system. By this method the reduced order model guarantees stability if the original high order model is stable. In the second method Particle Swarm Optimization (PSO) is employed to reduce the higher order model. PSO method is based on the minimization of the Integral Squared Error (ISE) between the transient responses of original higher order model and the reduced order model pertaining to a unit step input. Both the methods are illustrated through numerical examples.

**Keywords:**
Model Order Reduction,
Markov Parameters,
Routh Approximation,
Particle Swarm Optimization,
Integral Squared Error,
Steady State Stability.

##### 382 On Diffusion Approximation of Discrete Markov Dynamical Systems

**Authors:**
Jevgenijs Carkovs

**Abstract:**

**Keywords:**
Markov dynamical system,
diffusion approximation,
equilibrium stochastic stability.

##### 381 A Markov Chain Approximation for ATS Modeling for the Variable Sampling Interval CCC Control Charts

**Authors:**
Y. K. Chen,
K. C. Chiou,
C. Y. Chen

**Abstract:**

**Keywords:**
Cumulative conformance count,
variable sampling
interval,
Markov Chain,
average time to signal,
control chart.

##### 380 Accurate And Efficient Global Approximation using Adaptive Polynomial RSM for Complex Mechanical and Vehicular Performance Models

**Authors:**
Y. Z. Wu,
Z. Dong,
S. K. You

**Abstract:**

**Keywords:**
Global approximation,
polynomial response surface,
domain decomposition,
domain combination,
multiphysics modeling,
hybrid powertrain optimization

##### 379 A Model to Study the Effect of Na+ ions on Ca2+diffusion under Rapid Buffering Approximation

**Authors:**
Vikas Tewari,
K.R. Pardasani

**Abstract:**

**Keywords:**
rapid buffer approximation,
sodium-calcium exchangeprotein,
Sarcolemmal Calcium ATPase pump,
buffer disassociationrate,
forward time centred space.

##### 378 EMD-Based Signal Noise Reduction

**Authors:**
A.O. Boudraa,
J.C. Cexus,
Z. Saidi

**Abstract:**

This paper introduces a new signal denoising based on the Empirical mode decomposition (EMD) framework. The method is a fully data driven approach. Noisy signal is decomposed adaptively into oscillatory components called Intrinsic mode functions (IMFs) by means of a process called sifting. The EMD denoising involves filtering or thresholding each IMF and reconstructs the estimated signal using the processed IMFs. The EMD can be combined with a filtering approach or with nonlinear transformation. In this work the Savitzky-Golay filter and shoftthresholding are investigated. For thresholding, IMF samples are shrinked or scaled below a threshold value. The standard deviation of the noise is estimated for every IMF. The threshold is derived for the Gaussian white noise. The method is tested on simulated and real data and compared with averaging, median and wavelet approaches.

**Keywords:**
Empirical mode decomposition,
Signal denoisingnonstationary process.

##### 377 GPS Signal Correction to Improve Vehicle Location during Experimental Campaign

**Authors:**
L. Della Ragione,
G. Meccariello

**Abstract:**

In recent years in Italy the progress of the automobile industry, in the field of reduction of emissions values, is very remarkable. Nevertheless their evaluation and reduction is a key problem, especially in the cities, that account for more than 50% of world population. In this paper we dealt with the problem of describing a quantitatively approach for the reconstruction of GPS coordinates and altitude, in the context of correlation study between driving cycles / emission / geographical location, during an experimental campaign realized with some instrumented cars.

**Keywords:**
Air pollution,
Driving cycles,
GPS signal.

##### 376 Algorithm of Measurement of Noise Signal Power in the Presence of Narrowband Interference

**Authors:**
Alexey V. Klyuev,
Valery P. Samarin,
Viktor F. Klyuev

**Abstract:**

A power measurement algorithm of the input mix components of the noise signal and narrowband interference is considered using functional transformations of the input mix in the postdetection processing channel. The algorithm efficiency analysis has been carried out for different interference-to-signal ratio. Algorithm performance features have been explored by numerical experiment results.

**Keywords:**
Noise signal,
continuous narrowband interference,
signal power,
spectrum width,
detection.

##### 375 Approximation Algorithm for the Shortest Approximate Common Superstring Problem

**Authors:**
A.S. Rebaï,
M. Elloumi

**Abstract:**

**Keywords:**
Shortest approximate common superstring,
approximation algorithms,
strings overlaps,
complexities.

##### 374 A Study on the Least Squares Reduced Parameter Approximation of FIR Digital Filters

**Authors:**
S. Seyedtabaii,
E. Seyedtabaii

**Abstract:**

**Keywords:**
Digital filter,
filter approximation,
least squares,
model order reduction.

##### 373 An Approximation of Daily Rainfall by Using a Pixel Value Data Approach

**Authors:**
Sarisa Pinkham,
Kanyarat Bussaban

**Abstract:**

The research aims to approximate the amount of daily rainfall by using a pixel value data approach. The daily rainfall maps from the Thailand Meteorological Department in period of time from January to December 2013 were the data used in this study. The results showed that this approach can approximate the amount of daily rainfall with RMSE=3.343.

**Keywords:**
Daily rainfall,
Image processing,
Approximation,
Pixel value data.

##### 372 Nonlinear Power Measurement Algorithm of the Input Mix Components of the Noise Signal and Pulse Interference

**Authors:**
Alexey V. Klyuev,
Valery P. Samarin,
Viktor F. Klyuev,
Andrey V. Klyuev

**Abstract:**

A power measurement algorithm of the input mix components of the noise signal and pulse interference is considered. The algorithm efficiency analysis has been carried out for different interference-to-signal ratio. Algorithm performance features have been explored by numerical experiment results.

**Keywords:**
Noise signal,
pulse interference,
signal power,
spectrum width,
detection.

##### 371 An Empirical Validation of the Linear- Hyperbolic Approximation of the I-V Characteristic of a Solar Cell Generator

**Authors:**
A. A. Penin

**Abstract:**

An empirical linearly-hyperbolic approximation of the I - V characteristic of a solar cell is presented. This approximation is based on hyperbolic dependence of a current of p-n junctions on voltage for large currents. Such empirical approximation is compared with the early proposed formal linearly-hyperbolic approximation of a solar cell. The expressions defining laws of change of parameters of formal approximation at change of a photo current of family of characteristics are received. It allows simplifying a finding of parameters of approximation on actual curves, to specify their values. Analytical calculation of load regime for linearly - hyperbolic model leads to quadratic equation. Also, this model allows to define soundly a deviation from the maximum power regime and to compare efficiency of regimes of solar cells with different parameters.

**Keywords:**
a solar cell generator,
I − V characteristic,
p − n junction,
approximation

##### 370 Optimal Data Compression and Filtering: The Case of Infinite Signal Sets

**Authors:**
Anatoli Torokhti,
Phil Howlett

**Abstract:**

We present a theory for optimal filtering of infinite sets of random signals. There are several new distinctive features of the proposed approach. First, we provide a single optimal filter for processing any signal from a given infinite signal set. Second, the filter is presented in the special form of a sum with p terms where each term is represented as a combination of three operations. Each operation is a special stage of the filtering aimed at facilitating the associated numerical work. Third, an iterative scheme is implemented into the filter structure to provide an improvement in the filter performance at each step of the scheme. The final step of the concerns signal compression and decompression. This step is based on the solution of a new rank-constrained matrix approximation problem. The solution to the matrix problem is described in this paper. A rigorous error analysis is given for the new filter.

**Keywords:**
stochastic signals,
optimization problems in signal processing.

##### 369 Reliability Approximation through the Discretization of Random Variables using Reversed Hazard Rate Function

**Authors:**
Tirthankar Ghosh,
Dilip Roy,
Nimai Kumar Chandra

**Abstract:**

Sometime it is difficult to determine the exact reliability for complex systems in analytical procedures. Approximate solution of this problem can be provided through discretization of random variables. In this paper we describe the usefulness of discretization of a random variable using the reversed hazard rate function of its continuous version. Discretization of the exponential distribution has been demonstrated. Applications of this approach have also been cited. Numerical calculations indicate that the proposed approach gives very good approximation of reliability of complex systems under stress-strength set-up. The performance of the proposed approach is better than the existing discrete concentration method of discretization. This approach is conceptually simple, handles analytic intractability and reduces computational time. The approach can be applied in manufacturing industries for producing high-reliable items.

**Keywords:**
Discretization,
Reversed Hazard Rate,
Exponential
distribution,
reliability approximation,
engineering item.