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ABSTRACT: In this paper, the detection of weak signals in additive noise described by the first-order moving average (FOMA) of an impulsive process is considered. Specifically, decision regions of the maximum likelihood (ML) and suboptimum ML (S-ML) detectors are derived in the FOMA noise model, and specific examples of the ML and S-ML decision regions are obtained. The ML and S-ML detectors are employed in the antipodal signaling system and compared in terms of bit error rate in an impulsive noise environment. Numerical results show that the S-ML detector, despite its reduced complexity and simpler structure, exhibits practically the same performance as the optimum ML detector. It is also observed that the performance gap between detectors for FOMA and independent and identically distributed noise becomes larger as the degree of noise impulsiveness increases
IEEE Transactions on Vehicular Technology 02/2007; · 1.92 Impact Factor
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ABSTRACT: In this paper, the performance of rake receivers in the presence of fading and impulsive noise is addressed. The optimum maximum likelihood (ML) rake receiver for impulsive fading channel is derived, and a suboptimum rake receiver with a reduced complexity is obtained for practical purposes. Numerical results show that the suboptimum rake receiver exhibits almost the same performance as the optimum rake receiver. It is also observed that, as the number of fingers of a rake receiver increases, the performance of the rake receiver designed for impulsive environment improves, while the rake receiver optimized for Gaussian environment experiences performance degradation in an impulsive environment
IEEE Transactions on Vehicular Technology 12/2006; · 1.92 Impact Factor
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ABSTRACT: A high repetitive, compact and low-debris Xenon Z-pinch discharge system has been designed and fabricated as an EUV light source, in which a newly developed gas jet-type Z-pinch source is used. The discharge head has a coaxial double nozzle and a diffuser. Xenon Z-pinch plasma that emits EUV light is produced between the inner nozzle and the corresponding diffuser. An annular shell of a He gas curtain produced by the outer nozzle is specially designed for shielding the debris and suppressing the inner gas expansion. We have succeeded in generating EUV emitting plasma of 0.14 mm FWHM diameter and 0.80 mm FWHM length. We have also developed a new pulse power supply system, which has two magnetic pulse compression stages to achieve higher discharge current
Discharges and Electrical Insulation in Vacuum, 2006. ISDEIV '06. International Symposium on; 10/2006
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ABSTRACT: This paper presents different approaches to design and implement a fuzzy logic controller (FLC) for an intelligent parking system (IPS). In recent years fuzzy logic has been adopted for scientific and engineering applications. FLC is particularly successful in the area of system control when human expert knowledge is available. It provides an alternative much simpler than the use of an analytical model. FLC can be implemented on an FPGA (field-programmable gate array) using software or hardware approach. With the software approach, FLC is performed on a flexible FPGA soft core processor. The FLC is developed and tested on a reconfigurable FPGA board
Design and Test of Integrated Systems in Nanoscale Technology, 2006. DTIS 2006. International Conference on; 10/2006
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ABSTRACT: In this correspondence, we address the derivation of joint distributions and correlation coefficients for seven pairs of statistics used commonly in a number of signal detection schemes. The upper and lower bounds of the correlation coefficients are obtained, and relationships among the correlation coefficients are derived. Explicit values of the correlation coefficients evaluated for some specific noise distributions are shown for easy reference.
IEEE Transactions on Information Theory 06/2006; · 3.01 Impact Factor
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ABSTRACT: The authors investigate the performance of two types of
direct-sequence spread-spectrum multiple-access (DS/SSMA) systems in an
impulsive noise, Rician fading environment. It is observed that it is
possible to get some coding gain over uncoded systems except at low SNR
and that additional coding gain can be obtained by using optimum
asymmetric TCM. It is also shown that the performance of the DS/SSMA
systems degrades more as the noise becomes more impulsive
IEE Proceedings - Communications 09/1998; · 0.32 Impact Factor
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ABSTRACT: The authors consider the discrete-time signal detection problem
under the presence of additive noise exhibiting weak dependence. They
first propose a weakly dependent noise model, in which the additive
noise is modelled as a moving average process. They derive the locally
optimum, memoryless, and one-memory detector test statistics under the
model. The asymptotic performance of the one-memory detector is compared
with that of the locally optimum and memoryless detectors. Specific
examples for the asymptotic performance comparison of these detectors
are considered. The authors also investigate the finite sample-size
performance of several detectors through Monte-Carlo simulation. It is
observed that the one-memory detector can achieve almost optimum
performance at the expense of only one memory unit under the weakly
dependent noise model, and is rather insensitive to slight model change
IEE Proceedings - Vision Image and Signal Processing 11/1994;
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ABSTRACT: In the article an application of the fuzzy testing of hypothesis
to the stochastic-signal detection problem is considered when the
signal-to-noise ratio approaches zero. We first obtain the general
relationship between the test statistic of the locally optimum fuzzy
detector and that of the locally optimum detector. Based on this result,
the test statistic and structures of the locally optimum fuzzy detector
for stochastic signals are obtained. Several aspects of the locally
optimum fuzzy nonlinearity for stochastic signals are also described.
Finally, performance characteristics of the locally optimum fuzzy
detector are briefly discussed
IEEE Transactions on Systems Man and Cybernetics 10/1993;
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ABSTRACT: The design and implementation results of a fifth-order Chebychev
filter using switched-current or (SI) bilinear integrators are
presented. The signal-flow graph of the filter is derived from an LC
ladder and is composed of basic building blocks of bilinear integrators.
These bilinear integrators are implemented using an SI integrator. Using
a 1.2-μm CMOS4S process, simulation results of the bilinear
integrator as well as the filter using CADENCE are shown, both at the
schematic level and the layout level
Circuits and Systems, 1993., ISCAS '93, 1993 IEEE International Symposium on; 06/1993
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ABSTRACT: The performance of a DS/SSMA (direct-sequence spread-spectrum
multiaccess) system with hard-limiting correlation receivers is analyzed
over nonselective Rician fading channels with impulsive noise. More
specifically, computation of the average bit-error probabilities of the
DS/SSMA system have been accomplished in this paper by exact computation
for short spreading sequences and by approximation for long spreading
sequences
Signals, Systems and Computers, 1992. 1992 Conference Record of The Twenty-Sixth Asilomar Conference on; 11/1992
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ABSTRACT: Nonparametric detection of a zero-mean random signal in additive
noise is considered. The locally optimum detector based on signs and
ranks of observations is derived, for good weak-signal detection
performance under any specified noise probability density function. This
detector is shown to have interesting similarities to the locally
optimum detector for random signals. It may also be viewed as a
generalization of the locally optimum rank detector for known signals.
Examples of the test statistic of the detector are given for some
specific noise probability density functions. Asymptotic and finite
sample-size performance of the locally optimum rank detector is also
considered
IEEE Transactions on Information Theory 08/1992; · 3.01 Impact Factor
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ABSTRACT: Performance characteristics of the locally optimum detector for
composite signals in additive and multiplicative noise are investigated.
A noise model in which the effects of both additive and multiplicative
noise components can simultaneously be considered for a signal detection
problem is used. The signal is a composite which contains both
deterministic and stochastic signal components. To illustrate the
performance of the locally optimum detector, finite sample-size
performance characteristics of the locally optimum detector are obtained
and compared with those of other detectors
Military Communications Conference, 1991. MILCOM '91, Conference Record, 'Military Communications in a Changing World'., IEEE; 12/1991
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ABSTRACT: A class of nonlinear filters that are based on the rank estimates
( R -estimates) of location parameters in statistical theory is
introduced. It is shown how moving-window rank filters
( R -filters) can be defined starting from rank estimates of
location. These filters utilize the relative ranks of the observations
in each window to produce an output value. The idea of rank
Winsorization is extended to that of averaging only observations which
lie within small temporal neighborhoods. This leads to a definition of
the class of generalized Wilcoxon (GW) filters, which are parameterized
by three parameters, namely the degrees of temporal and rank
Winsorization and the degree of averaging. The GW filters can be defined
to have desirable characteristics of edge preservation, detail
retention, and impulse rejection, in addition to the property of
Gaussian noise smoothing. Performance characteristics of these filters
are considered through analysis and simulation. The filters show that
all three well-known classes of robust location estimates, the
L -, M -, and R -estimates, can be applied to
nonlinear smoothing of signals
IEEE Transactions on Acoustics Speech and Signal Processing 10/1989;
