symbol by symbol map demodulation of cpm and psk signals on rayleigh flat fading channels demodulation using the symbol by symbol maximum a posteriori probability map algorithm is presented the algorithm is derived for the case of continuous phase modulation cpm signals transmitted over rayleigh flat fading channels and a corresponding receiver structure is specified it is shown that the map algorithm requires computing for each trellis branch the sum of the products of the weights of all paths through the trellis which pass through that branch and that this generic computational problem can be solved efficiently by an approach that uses a forward and backward recursion through the trellis simulation results are presented which show both the hard and soft decision performance of the map receiver to be robust even in the presence of fade rates of up to 30 of the symbol rate the application of the receiver concept to phase shift keying psk signals is also discussed and then evaluated via simulation the concept of joint demodulation and decoding using iterative processing techniques is introduced it is shown that the map receiver is well suited for iterative processing applications due to its use of a priori symbol probabilities and its production of optimal soft decisions simulation results for the reception of quaternary psk qpsk show that the bit error rate ber performance of the iterative map receiver can approach that of a receiver operating with perfect knowledge of the fading process

a new completely general class of variational inclusions with noncompact valued mappings abstract in this paper we introduce and study a new completely general class of variational inclusions with noncompact valued mappings and construct some new iterative algorithms we prove the existence of solutions for the completely general class of variational inclusions and the convergence of iterative sequences generated by the algorithms

perturbed proximal point algorithms for general quasi variational like inclusions in this paper we introduce two new concepts of subdifferential and proximal mappings of proper functionals on hilbert spaces the existence and lipschitz continuity of proximal mapping of a proper functional are proved by applying these concepts we introduce and study a class of general quasi variational like inclusions and develop some new perturbed proximal point algorithms of mann and ishikawa type for finding the approximate solutions of the general quasi variational like inclusions the convergence criteria of the sequences of approximate solutions generated by these new algorithms are also discussed our algorithms and results improve and generalize many known results in the literature

on interleaved differentially encoded convolutional codes we study a serially interleaved concatenated code construction where the outer code is a standard convolutional code and the inner code is a recursive convolutional code of rate 1 we focus on the ubiquitous inner differential encoder used in particular to resolve phase ambiguities double differential encoder used to resolve both phase and frequency ambiguities and another rate 1 recursive convolutional code of memory 2 we substantiate analytically the rather surprising result that the error probabilities corresponding to a maximum likelihood ml coherently detected antipodal modulation over the additive white gaussian noise awgn channel for this construction are advantageous as compared to the stand alone outer convolutional code this is in spite of the fact that the inner code is of rate 1 the analysis is based on the tangential sphere upper bound of an ml decoder incorporating the ensemble weight distribution wd of the concatenated code where the ensemble is generated by all random and uniform interleavers this surprising result is attributed to the wd thinning observed for the concatenated scheme which shapes the wd of the outer convolutional code to resemble more closely the binomial distribution typical of a fully random code of the same length and rate this gain is maintained regardless of a rather dramatic decrease as demonstrated here in the minimum distance of the concatenated scheme as compared to the minimum distance of the outer stand alone convolutional code the advantage of the examined serially interleaved concatenated code given in terms of bit and or block error probability which is decoded by a practical suboptimal decoder over the optimally decoded standard convolutional code is demonstrated by simulations and some insights into the performance of the iterative decoding algorithm are also discussed though we have investigated only specific constructions of constituent inner rate 1 and outer codes we trust hinging on the rational of the arguments here that these results extend to many other constituent convolutional outer codes and rate 1 inner recursive convolutional codes

on improved bounds on the decoding error probability of block codes over interleaved fading channels with applications to turbo like codes we derive here improved upper bounds on the decoding error probability of block codes which are transmitted over fully interleaved rician fading channels coherently detected and maximum likelihood ml decoded we assume that the fading coefficients during each symbol are statistically independent due to a perfect channel interleaver and that perfect estimates of these fading coefficients are provided to the receiver the improved upper bounds on the block and bit error probabilities are derived for fully interleaved fading channels with various orders of space diversity and are found by generalizing some previously introduced upper bounds for the binary input additive white gaussian nose awgn channel the advantage of these bounds over the ubiquitous union bound is demonstrated for some ensembles of turbo codes and low density parity check ldpc codes and it is especially pronounced in a portion of the rate region exceeding the cutoff rate our generalization of the duman and salehi bound duman and salehi 1998 duman 1998 which is based on certain variations of gallager s 1965 bounding technique is demonstrated to be the tightest reported upper bound we therefore apply it to calculate numerically upper bounds on the thresholds of some ensembles of turbo like codes referring to the optimal ml decoding for certain ensembles of uniformly interleaved turbo codes the upper bounds derived here also indicate good match with computer simulation results of efficient iterative decoding algorithms

a new upper bound on the ml decoding error probability of linear binary block codes in awgn interference performance evaluation of maximum likelihood ml soft decision decoded binary block codes is usually carried out using bounding techniques many tight upper bounds on the error probability of binary codes are based on the so called gallager s first bounding technique gfbt the tangential sphere bound tsb of poltyrev which has been believed for many years to offer the tightest bound developed for binary block codes is an example within the framework of the tsb and gfbt we apply a new method referred to as the added hyper plane ahp technique to the decomposition of the error probability this results in a bound developed upon the application of two stages of the gfbt with two different gallager regions culminating in a tightened upper bound beyond the tsb the proposed bound is simple and only requires the spectrum of the binary code

on the error exponents of improved tangential sphere bounds the performance of maximum likelihood ml decoded binary linear block codes over the additive white gaussian noise awgn channel is addressed via the tangential sphere bound tsb and two of its recent improved versions the correspondence is focused on the derivation of the error exponents of these bounds although it was shown that some recent improvements of the tsb tighten this bound for finite length codes it is demonstrated in this correspondence that their error exponents coincide for an arbitrary ensemble of binary linear block codes the common value of these error exponents is explicitly expressed in terms of the asymptotic growth rate of the average distance spectrum

perturbed proximal point algorithms for generalized quasivariational inclusions abstract in this paper we study a class of generalized quasivariational inclusions by using the properties of the resolvent operator associated with a maximal monotone mapping in hilbert space we have established an existence theorem of solutions for generalized quasivariational inclusions suggesting a new iterative algorithm and a perturbed proximal point algorithm for finding approximate solutions which strongly converge to the exact solution of the generalized quasivariational inclusions as special cases some known results in this field are also discussed

auxiliary principle and iterative algorithms for generalized set valued strongly nonlinear mixed variational like inequalities in this paper we extend the auxiliary principle technique to study a class of generalized set valued strongly nonlinear mixed variational like inequalities we prove the existence of a solution of the auxiliary problem for the generalized set valued strongly nonlinear mixed variational like inequalities construct the iterative algorithm for the generalized set valued strongly nonlinear mixed variational like inequalities and show the existence of a solution of the generalized set valued strongly nonlinear mixed variational like inequality by using the auxiliary principle technique we also prove the convergence of iterative sequences generated by the algorithm

joint noncoherent demodulation and decoding for the block fading channel a practical framework for approaching shannon capacity the paper contains a systematic investigation of practical coding strategies for noncoherent communication over fading channels guided by explicit comparisons with information theoretic benchmarks noncoherent reception is interpreted as joint data and channel estimation assuming that the channel is time varying and a priori unknown we consider iterative decoding for a serial concatenation of a standard binary outer channel code with an inner modulation code amenable to noncoherent detection for an information rate of about 1 2 bit per channel use the proposed scheme using a quaternary phase shift keying qpsk alphabet provides performance within 1 6 1 7 db of shannon capacity for the block fading channel and is about 2 5 3 db superior to standard differential demodulation in conjunction with an outer channel code we also provide capacity computations for noncoherent communication using standard phase shift keying psk and quadrature amplitude modulation qam alphabets comparing these with the capacity with unconstrained input provides guidance as to the choice of constellation as a function of the signal to noise ratio these results imply that qpsk suffices to approach the unconstrained capacity for the relatively low information and fading rates considered in our performance evaluations but that qam is superior to psk for higher information or fading rates motivating further research into efficient noncoherent coded modulation with qam alphabets

a distance spectrum interpretation of turbo codes the performance of turbo codes is addressed by examining the code s distance spectrum the error floor that occurs at moderate signal to noise ratios is shown to be a consequence of the relatively low free distance of the code it is also shown that the error floor can be lowered by increasing the size of the interleaver without changing the free distance of the code alternatively the free distance of the code may be increased by using primitive feedback polynomials the excellent performance of turbo codes at low signal to noise ratios is explained in terms of the distance spectrum the interleaver in the turbo encoder is shown to reduce the number of low weight codewords through a process called spectral thinning this thinned distance spectrum results in the free distance asymptote being the dominant performance parameter for low and moderate signal to noise ratios

new performance bounds for turbo codes we derive a new upper bound on the word and bit error probabilities of turbo codes with maximum likelihood decoding by using the gallager bound since the derivation of the bound for a given interleaver is intractable we assume uniform interleaving as in the derivation of the standard union bound for turbo codes the result is a generalization of the transfer function bound and remains useful for a wider range of signal to noise ratios particularly for some range below the channel cutoff rate the new bound is also applicable to other linear codes

tightened upper bounds on the ml decoding error probability of binary linear block codes the performance of maximum likelihood ml decoded binary linear block codes is addressed via the derivation of tightened upper bounds on their decoding error probability the upper bounds on the block and bit error probabilities are valid for any memoryless binary input and output symmetric communication channel and their effectiveness is exemplified for various ensembles of turbo like codes over the additive white gaussian noise awgn channel an expurgation of the distance spectrum of binary linear block codes further tightens the resulting upper bounds

target locus scaling for modeling formant transitions in vowel consonant vowel utterances the coarticulatory effects described by ohman j acoust soc am 39 151 168 1966 imply that consonant loci cannot always be defined by their associated consonantal contexts alone but in swedish vowel consonant vowel utterances they must also depend on their trans consonantal vowels tcvs his discovery is extended here using a model with tcv dependent consonant loci and with a unique target for each vowel the model accurately characterizes the vowel to consonant and consonant to vowel transitions for the b and d contexts from ohman s second formant frequency data as families connected by linear scaling relationships

coded modulation in the block fading channel coding theorems and code construction we consider coded modulation schemes for the block fading channel in the setting where a codeword spans a finite number n of fading degrees of freedom we show that coded modulations of rate r bit per complex dimension over a finite signal set spl chi spl sube spl copf of size 2 sup m achieve the optimal rate diversity tradeoff given by the singleton bound spl delta n m r 1 spl lfloor n 1 r m spl rfloor for r spl isin 0 m spl rfloor furthermore we show also that the popular bit interleaved coded modulation achieves the same optimal rate diversity tradeoff we present a novel coded modulation construction based on blockwise concatenation that systematically yields singleton bound achieving turbo like codes defined over an arbitrary signal set spl chi spl sub spl copf the proposed blockwise concatenation significantly outperforms conventional serial and parallel turbo codes in the block fading channel we analyze the ensemble average performance under maximum likelihood ml decoding of the proposed codes by means of upper bounds and tight approximations we show that differently from the additive white gaussian noise awgn and fully interleaved fading cases belief propagation iterative decoding performs very close to ml on the block fading channel for any signal to noise ratio snr and even for relatively short block lengths we also show that at constant decoding complexity per information bit the proposed codes perform close to the information outage probability for any block length while standard block codes e g obtained by trellis termination of convolutional codes have a gap from outage that increases with the block length this is a different and more subtle manifestation of the so called interleaving gain of turbo codes

differential turbo coded modulation with app channel estimation a serially concatenated coding system which can operate without channel state information csi with use of a simple channel estimation technique is presented this channel estimation technique uses the inner decoder s a posteriori probability app information about the transmitted symbols to form a channel estimate for each symbol interval and is termed app channel estimation the serially concatenated code is comprised of an outer rate 2 3 binary error control code separated by a bit interleaver from an inner code consisting of an 8 phase shift keying psk bit mapping and differential 8 psk modulation coherent decoding provides bit error rate performance 0 6 db from 8 psk capacity for large interleaver sizes app channel estimation decoding without initial csi over constant and random walk phase models shows near coherent results with fractions of a decibel performance loss for random walk and linear phase models

on the asymptotic input output weight distributions and thresholds of convolutional and turbo like encoders we present a general method for computing the asymptotic input output weight distribution of convolutional encoders in some instances one can derive explicit analytic expressions in general though to determine the growth rate of the input output weight distribution for a particular normalized input weight spl kappa and output weight spl omega a system of polynomial equations has to be solved this method is then used to determine the asymptotic weight distribution of various concatenated code ensembles and to derive lower bounds on the thresholds of these ensembles under maximum likelihood ml decoding

bounds on the decoding error probability of binary linear codes via their spectra bounds on the error probability of maximum likelihood decoding of a binary linear code are considered the bounds derived use the weight spectrum of the code and they are tighter than the conventional union bound in the case of large noise in the channel the bounds derived are applied to a code with an average spectrum and the result is compared to the random coding exponent the author shows that the bound considered for the binary symmetrical channel case coincides asymptotically with the random coding bound for the case of awgn channel the author shows that berlekamp s 1980 tangential bound can be improved but even this improved bound does not coincide with the random coding bound although it can be very close to it

new techniques for upper bounding the ml decoding performance of binary linear codes in this paper new techniques are presented to either simplify or improve most existing upper bounds on the maximum likelihood ml decoding performance of the binary linear codes over additive white gaussian noise awgn channels firstly the recently proposed union bound using truncated weight spectrum by ma et al is re derived in a detailed way based on gallager s first bounding technique gfbt where the good region is specified by a sub optimal list decoding algorithm the error probability caused by the bad region can be upper bounded by the tail probability of a binomial distribution while the error probability caused by the good region can be upper bounded by most existing techniques secondly we propose two techniques to tighten the union bound on the error probability caused by the good region the first technique is based on pair wise error probabilities the second technique is based on triplet wise error probabilities which can be upper bounded by the fact that any three bipolar vectors form a non obtuse triangle the proposed bounds improve the conventional union bounds but have a similar complexity since they involve only the q function the proposed bounds can also be adapted to bit error probabilities

a perturbed algorithm for variational inclusions a perturbed method for solving a new class of variational inclusions is presented and a convergence result which includes as a special case some known results in this field is given

mann and ishikawa type perturbed iterative algorithms for generalized quasivariational inclusions abstract in this paper we introduce a class of generalized quasivariational inclusions and show its equivalence with a class of fixed point problems by making use of the properties of proximal maps using this equivalence we develop the mann and ishikawa type perturbed iterative algorithms for this class of generalized quasivariational inclusions further using fixed point techniques we prove the existence of solutions for the class of generalized quasivariational inclusions and discuss the convergence criteria for the perturbed algorithms our algorithms and results improve and generalize many known corresponding algorithms and results

a system of generalized variational inclusions involving generalized h accretive mapping in real q uniformly smooth banach spaces abstract in this paper we consider a class of accretive mappings called generalized h accretive mappings in banach spaces we prove that the proximal point mapping of the generalized h accretive mapping is single valued and lipschitz continuous further we consider a system of generalized variational inclusions involving generalized h accretive mappings in real q uniformly smooth banach spaces using proximal point mapping method we prove the existence and uniqueness of solution and suggest an iterative algorithm for the system of generalized variational inclusions furthermore we discuss the convergence criteria of the iterative algorithm under some suitable conditions our results can be viewed as a refinement and improvement of some known results in the literature

improved upper bounds on the ml decoding error probability of parallel and serial concatenated turbo codes via their ensemble distance spectrum the ensemble performance of parallel and serial concatenated turbo codes is considered where the ensemble is generated by a uniform choice of the interleaver and of the component codes taken from the set of time varying recursive systematic convolutional codes following the derivation of the input output weight enumeration functions of the ensembles of random parallel and serial concatenated turbo codes the tangential sphere upper bound is employed to provide improved upper bounds on the block and bit error probabilities of these ensembles of codes for the binary input additive white gaussian noise awgn channel based on coherent detection of equi energy antipodal signals and maximum likelihood decoding the influence of the interleaver length and the memory length of the component codes is investigated the improved bounding technique proposed here is compared to the conventional union bound and to a alternative bounding technique by duman and salehi 1998 which incorporates modified gallager bounds the advantage of the derived bounds is demonstrated for a variety of parallel and serial concatenated coding schemes with either fixed or random recursive systematic convolutional component codes and it is especially pronounced in the region exceeding the cutoff rate where the performance of turbo codes is most appealing these upper bounds are also compared to simulation results of the iterative decoding algorithm

an iterative method for generalized nonlinear set valued mixed quasi variational inequalities with h monotone mappings generalized nonlinear set valued mixed quasi variational inequalities with maximal monotone mappings have been studied in the literature since the maximal monotone operators are known as special cases of the h monotone operators we generalize the study for these inequality problems with h monotone mappings in this paper precisely we establish the existence of solutions for the generalized nonlinear set valued mixed quasi variational inequality problem with h monotone mappings an iterative method for finding their approximate solutions are proposed furthermore a new convergence criteria for this iterative method is imposed

an analytical method for approximate performance evaluation of binary linear block codes an analytical method for approximate performance evaluation of binary linear block codes using an additive white gaussian noise channel model with binary phase shift keying modulation is presented we focus on the probability density function of the bit log likelihood ratio llr which is expressed in terms of the gram charlier series expansion this expansion requires knowledge of the statistical moments of the bit llr we introduce an analytical method for calculating these moments this is based on some recursive calculations involving certain weight enumerating functions of the code it is proved that the approximation can be as accurate as desired if we use enough terms in the gram charlier series expansion numerical results are provided for some examples which demonstrate close agreement with simulation results

iterative decoding of space time differentially coded unitary matrix modulation noncoherent communication over the rayleigh flat fading channel with multiple transmit and receive antennas is investigated codes achieving bit error rate ber lower than 10 sup 4 at bit energy over the noise spectral density ratio e sub b n sub 0 of 0 8 to 2 8 db from the capacity limit were found with coding rates of 0 5 to 2 25 bits per channel use the codes are serial concatenation of a turbo code and a unitary matrix differential modulation code the receiver is based on a high performance joint iterative decoding of the turbo code and the modulation code information theoretic arguments are harnessed to form guidelines for code design and to evaluate performance of the iterative decoder

upper bounds to error probabilities of coded systems beyond the cutoff rate a family of upper bounds to error probabilities of coded systems was recently proposed by d divsalar see ieee communication theory workshop 1999 jpl tmo prog rep 42 139 1999 these bounds are valid for transmission over the additive white gaussian noise channel and require only the knowledge of the weight spectrum of the code words after illustrating these bounds we extend them to fading channels contrary to the union bound our bounds maintain their effectiveness below the signal to noise ratio snr at which the cutoff rate of the channel equals the rate of the code some applications are shown first we derive upper bounds to the minimum snr necessary to achieve zero error probability as the code block length increases to infinity next we use our bounds to predict the performance of turbo codes and low density parity check codes

generalized tangential sphere bound on the ml decoding error probability of linear binary block codes in awgn interference the error probability of maximum likelihood ml soft decision decoded binary block codes rarely accepts nice closed forms in addition for long codes ml decoding becomes prohibitively complex nevertheless bounds on the performance of ml decoded systems provide insight into the effect of system parameters on the overall system performance as well as a measure of goodness of the suboptimum decoding methods used in practice using the so called gallager s first bounding technique involving a so called gallager region and within the framework of tangential sphere bound tsb of poltyrev we develop a general bound referred to as the generalized tsb gtsb the gallager region is chosen to be a general hyper surface of revolution hsr which is optimized to tighten the bound the search for the optimal gallager region is a classical problem dating back to gallager s thesis in the early 1960s for the random coding case gallager provided the optimal solution in a closed form while for the nonrandom case the problem has been an active area of research in information theory for many years we prove that for a sphere code the optimal hsr within the proposed gtsb is a hyper cone this will climax to the tsb of poltyrev one of the tightest bounds ever developed for binary block codes and therefore terminates the search for a better gallager region in the groundwork of the gtsb

the error probability of m ary psk block coded modulation schemes a tight upper bound on the decoding error probability is derived for block coded modulation structures where an m ary phase shift keying m psk signal constellation is employed this bound called a tangential sphere bound is tight for very low as well as for high signal to noise ratios snrs berlekamp s tangential union bound previously derived for binary codes can be derived for an m psk block coded modulation structure as well however it is proven that our tangential sphere bound is tighter than berlekamp s 1980 tangential bound for particular schemes it is shown that for low snrs our bound is considerably tighter than the tangential bound as one of the examples a multistage decoder is considered

sphere packing bounds revisited for moderate block lengths the main reference of this paper is the sphere packing bound of 1967 sp67 derived by shannon gallager and berlekamp it offers a lower bound on the decoding error probability over a very large variety of channels if it has failed so far to provide any usable material in practical implementation of telecommunication systems it is due to an original focus on asymptotic results making it inapplicable for moderate code lengths and to the difficulty of the involved methods which makes the derivation of sp67 quite hermetic and uninspiring for further research the purpose of this paper is two fold 1 to stir up some renewed interest in the topic on which shannon concluded his career in information theory thanks to a qualitative rather than technical review of the derivation of sp67 introduced by a review of the simpler sphere packing bound derived by shannon in 1959 2 to prove the practical interest of sp67 by extending its field of application to continuous output channels and particularly the additive white gaussian noise awgn channel used with any particular modulation scheme and by improving its lower bound for the moderate code length case so that it becomes the best lower bound for most iteratively decodable codes turbo codes low density parity check ldpc codes repeat accumulate ra codes etc of usual lengths

upper bound on the minimum distance of turbo codes an upper bound on the minimum distance of turbo codes is derived which depends only on the interleaver length and the component scramblers employed the derivation of this bound considers exclusively turbo encoder input words of weight 2 the bound does not only hold for a particular interleaver but for all possible interleavers including the best it is shown that in contrast to general linear binary codes the minimum distance of turbo codes cannot grow stronger than the square root of the block length this implies that turbo codes are asymptotically bad a rigorous proof for the bound is provided which is based on a geometric approach

on the error probability of signals in additive white gaussian noise a new upper bound to the probability of error in detecting one of m equally probable signals in additive white gaussian noise is presented this bound is easy to calculate can be applied to any signal set it is always better than the union and minimum distance bounds examples demonstrate the use of the bound

lower bounds on the error probability of block codes based on improvements on de caen s inequality new lower bounds on the error probability of block codes with maximum likelihood decoding are proposed the bounds are obtained by applying a new lower bound on the probability of a union of events derived by improving on de caen s lower bound the new bound includes an arbitrary function to be optimized in order to achieve the tightest results since the optimal choice of this function is known but leads to a trivial and useless identity we find several useful approximations for it each resulting in a new lower bound for the additive white gaussian noise awgn channel and the binary symmetric channel bsc the optimal choice of the optimization function is stated and several approximations are proposed when the bounds are further specialized to linear codes the only knowledge on the code used is its weight enumeration the results are shown to be tighter than the latest bounds in the current literature such as those by seguin 1998 and by keren and litsyn 2001 moreover for the bsc the new bounds widen the range of rates for which the union bound analysis applies thus improving on the bound to the error exponent compared with the de caen based bounds

the performance of serial turbo codes does not concentrate minimum distances and maximum likelihood error probabilities of serial turbo codes with uniform interleaver are analyzed it is shown that for a fraction of interleavers approaching one as the block length grows large the minimum distance of serial turbo codes grows as a positive power of their block length while their error probability decreases exponentially fast in some positive power of their block length on sufficiently good memoryless channels such a typical code behavior contrasts the performance of the average serial turbo code whose error probability is dominated by an asymptotically negligible fraction of poorly performing interleavers and decays only as a negative power of the block length the analysis proposed in this paper relies on precise bounds of the minimum distance of the typical serial turbo code whose scaling law is shown to depend both on the free distance of its outer constituent encoder which determines the exponent of its sub linear growth in the block length and on the effective free distance of its inner constituent encoder the latter is defined as the smallest weight of codewords obtained when the input word of the inner encoder has weight two and appears as a linear scaling factor for the minimum distance of the typical serial turbo code hence despite the lack of concentration of the maximum likelihood error probability around its expected value the main design parameters suggested by the average code analysis turn out to characterize also the performance of the typical serial turbo code by showing for the first time that the typical serial turbo code s minimum distance scales linearly in the effective free distance of the inner constituent encoder the presented results generalize and improve upon the probabilistic bounds of kahale and urbanke as well as the deterministic upper bound of bazzi mahdian and spielman where only the dependence on the outer encoder s free distance was proved

an investigation of locus equations as a source of relational invariance for stop place categorization locus equations were investigated as a potential metric capable of illustrating relational invariance for place of articulation in voiced initial stop consonants independently of vowel context locus equations are straight line regression fits to data points formed by plotting onsets of f2 transitions along the y axis and their corresponding midvowel nuclei along the x axis twenty subjects 10 male and 10 female produced b v t d v t and g v t tokens for ten vowel contexts each cvc token was repeated in a carrier phrase five times yielding 50 tokens per stop place category formant measures were obtained using the macspeech lab ii speech analysis system extremely linear regression functions were found characterized by distinct slopes and y intercepts as a function of place of articulation a discriminant analysis using f2onset and vowel frequencies as predictors showed 82 78 and 67 classification rates for labial alveolar and velar place using derived slope and y intercept values as predictors led to 100 classification into stop place categories a neurobiologically oriented perspective on the invariance issue is developed and a brain based recognition algorithm for stop place integrating burst and f2 trajectory cues is offered

well posedness of generalized mixed variational inequalities inclusion problems and fixed point problems we introduced and studied the concept of well posedness to a generalized mixed variational inequality some characterizations are given under suitable conditions we prove that the well posedness of the generalized mixed variational inequality is equivalent to the well posedness of the corresponding inclusion problem we also discuss the relations between the well posedness of the generalized mixed variational inequality and the well posedness of the corresponding fixed point problem finally we derive some conditions under which the generalized mixed variational inequality is well posed

variations on the gallager bounds connections and applications there has been renewed interest in deriving tight bounds on the error performance of specific codes and ensembles based on their distance spectrum we discuss many reported upper bounds on the maximum likelihood ml decoding error probability and demonstrate the underlying connections that exist between them in addressing the gallager bounds and their variations we focus on the duman and salehi see ieee trans commun vol 46 p 717 723 1998 variation which originates from the standard gallager bound a large class of efficient bounds or their chernoff versions is demonstrated to be a special case of the generalized second version of the duman and salehi bounds implications and applications of these observations are pointed out including the fully interleaved fading channel resorting to either matched or mismatched decoding the proposed approach can be generalized to geometrically uniform nonbinary codes finite state channels bit interleaved coded modulation systems and it can be also used for the derivation of upper bounds on the conditional decoding error probability

spectra and minimum distances of repeat multiple accumulate codes in this paper the ensembles of repeat multiple accumulate codes ram which are obtained by interconnecting a repeater with a cascade of m accumulate codes through uniform random interleavers are analyzed it is proved that the average spectral shapes of these code ensembles are equal to 0 below a threshold distance epsivm and moreover they form a nonincreasing sequence in m converging uniformly to the maximum between the average spectral shape of the linear random ensemble and 0 consequently the sequence epsivm converges to the gilbert varshamov gv distance a further analysis allows to conclude that if m ges 2 the ram are asymptotically good and that epsivm is the typical normalized minimum distance when the interleaver length goes to infinity combining the two results it is possible to conclude that the typical distance of the ensembles ram converges to the gilbert varshamov bound

characterization of h monotone operators with applications to variational inclusions this paper establishes necessary and sufficient conditions for operators to be h monotone based on these conditions we introduce a new iterative algorithm for solving a class of variational inclusions strong convergence of this algorithm is established under appropriate assumptions on the parameters estimate of its convergence rate is also provided

discussion on the existence and uniqueness of solution to nonlinear integro differential systems we present an abstract result for the existence and uniqueness of the solution of nonlinear integro differential systems involving the generalized p q laplacian the method used involves result on surjection of the sums of ranges of m accretive mappings and strongly accretive mappings the systems and technique discussed in this paper extend and complement some of the previous work

performance of parallel concatenated coding schemes in this paper ensembles of parallel concatenated codes are studied and rigorous results on their asymptotic performance under the assumption of maximum likelihood ml decoding are presented in particular it is proven that in any parallel concatenation scheme with k branches where all k encoders are recursive and the bhattacharyya parameter of the channel is sufficiently small the bit error rate ber and the word error rate go to 0 exactly like n 1 k and n 2 k respectively different types of ensembles by changing the subgroup of permutations used to interconnect the various encoders are considered

perturbed algorithms and sensitivity analysis for a general class of variational inclusions in the present paper we study a perturbed iterative method for solving a general class of variational inclusions an existence result which generalizes some known results in this field a convergence result and a new iterative method are given we also prove the continuity of the perturbed solution to a parametric variational inclusion problem several special cases are discussed

some new twists to problems involving the gaussian probability integral using an alternate form of the gaussian probability integral discovered a number of years ago it is shown that the solution to a number of previously considered communication problems can be simplified and in some cases made more accurate i e exact rather than bounded these problems include the evaluation of 1 the bit error probability of uncoded phase shift keying psk with costas loop tracking 2 word error probability of antipodal modulation in the presence of fading 3 bit error probability of coded m ary psk mpsk over the memoryless fading channel with given channel state information 4 conditional symbol error probability of mpsk in the presence of carrier synchronization error and 5 the average error probability for the binary additive white gaussian noise awgn intersymbol interference channel also obtained is a generalization of this new alternate form to the case of a two dimensional gaussian probability integral with arbitrary correlation which can be used to evaluate the symbol error probability of mpsk with i q unbalance

cross entropy and iterative decoding in this correspondence the relationship between iterative decoding and techniques for minimizing cross entropy is explained it is shown that minimum cross entropy mce decoding is an optimal lossless decoding algorithm but its complexity limits its practical implementation use of a maximum a posteriori map symbol estimation algorithm instead of the true mce algorithm provides practical algorithms that are identical to those proposed in the literature in particular turbo decoding is shown to be equivalent to an optimal algorithm for iteratively minimizing cross entropy under an implicit independence assumption

the mann process for perturbed m accretive operators in banach spaces this work was carried out while this author was visiting the university ofalabama in huntsville underthe nancial support by the lg yonam foundation 1998 and he would like to thank professor claudio h morales for his hospitality in the department of mathematics 0362 546x 01 see front matter 2001 elsevier science ltd all rights reserved pii s0362 546x 00 00115 2

a methodology for modeling vowel formant contours in cvc context models for the formant frequency contours of vowels in cvc context are presented and illustrated with an american english database comprising isolated syllables with c c b d g and v i i q ae a c u u v w both established and reinterpreted regularities among context effects are cast in a series of successively elaborated mathematical models the first model model i in common with all its successors embodies the notion of the superposition of cv and vc transitions according to which a formant trajectory fcvc n is modeled as fcv n tv gvc n where n is duration normalized time tv is a vowel target and fcv n and gvc n are initial and final consonant transition functions the rms errors for f1 f2 and f3 30 89 and 111 hz against independent test data are near the minimum theoretical values 32 69 and 100 hz predicted from interrepetition variation and its contribution to uncertainty in the model elements subsequently the elements of the additive model are individually characte

mann and ishikawa type perturbed iterative algorithms for generalized nonlinear implicit quasi variational inclusions abstract in this paper we introduce a new class of generalized nonlinear implicit quasi variational inclusions and prove its equivalence with a class of fixed point problems by making use of the properties of maximal monotone we also prove the existence of solutions for this generalized nonlinear implicit quasi variational inclusions and the convergence of iterative sequences generated by the perturbed algorithms

h monotone operator and resolvent operator technique for variational inclusions in this paper we introduce a new class of monotone operators h monotone operators the resolvent operator associated with an h monotone operator is defined and its lipschitz continuity is presented we also introduce and study a new class of variational inclusions involving h monotone operators and construct a new algorithm for solving this class of variational inclusions by using the resolvent operator technique

maximum likelihood differential detection of uncoded and trellis coded amplitude phase modulation over awgn and fading channels spl minus metrics and performance this paper derives metrics for maximum likelihood differential detection of uncoded and trellis coded mpsk and qam transmitted over rayleigh and rician fading channels receiver structures based on these metrics are proposed and their error probability performance analyzed and or simulated the results represent a generalization of the notion of multiple symbol differential detection previously introduced by the authors for mpsk over an awgn to the fading channel and other modulations for the coded cases ideal interleaving deinterleaving is assumed and furthermore the presence or absence of channel state information an interesting side result is that for a constant envelope modulation transmitted over a fading channel with unknown but rapidly varying phase error the other extreme to the slowly varying phase error case normally assumed for differential detection under certain practical assumptions it is shown that the optimum receiver is of the limiter discriminator type

unveiling turbo codes some results on parallel concatenated coding schemes a parallel concatenated coding scheme consists of two simple constituent systematic encoders linked by an interleaver the input bits to the first encoder are scrambled by the interleaver before entering the second encoder the codeword of the parallel concatenated code consists of the input bits to the first encoder followed by the parity check bits of both encoders this construction can be generalized to any number of constituent codes parallel concatenated schemes employing two convolutional codes as constituent codes in connection with an iterative decoding algorithm of complexity comparable to that of the constituent codes have been previously shown to yield remarkable coding gains close to theoretical limits they have been named and are known as turbo codes we propose a method to evaluate an upper bound to the bit error probability of a parallel concatenated coding scheme averaged over all interleavers of a given length the analytical bounding technique is then used to shed some light on some crucial questions which have been floating around in the communications community since the proposal of turbo codes

on relaxed viscosity iterative methods for variational inequalities in banach spaces in this paper we suggest and analyze a relaxed viscosity iterative method for a commutative family of nonexpansive self mappings defined on a nonempty closed convex subset of a reflexive banach space we prove that the sequence of approximate solutions generated by the proposed iterative algorithm converges strongly to a solution of a variational inequality our relaxed viscosity iterative method is an extension and variant form of the original viscosity iterative method the results of this paper can be viewed as an improvement and generalization of the previously known results that have appeared in the literature

equivalency of convergence between one step iteration algorithm and two step iteration algorithm of variational inclusions for h monotone mappings the aim of this paper is to establish the equivalence of convergence for h monotone mappings of variational inclusions between the one step iteration algorithm of the paper y p fang n j huang h monotone opertor and resolvent operator technique for variational inclusions appl math comput 145 2003 795 803 and the two step iteration algorithm of the paper l c zeng s m guu j c yao characterization of h monotone operators with applications to variational inclusions comput math appl 50 2005 329 337 it is clear from this paper that the one step iteration algorithm with easy implement and small computational workload has more advantages than the two step iteration algorithm