comparison and stability of solutions to a class of quasilinear parabolic problems on presente des resultats de comparaison et d unicite pour les solutions de problemes aux valeurs limites quasilineaires paraboliques avec et sans obstacles un resultat de stabilite dans l 1 donne la stabilisation asymptotique dans cet espace quand t vers le probleme elliptique correspondant

new sufficient conditions for robust stability analysis of interval matrices abstract this letter presents new sufficient conditions for robust hurwitz stability of interval matrices the proposed conditions are based on two approaches i finding a common lyapunov matrix for the interval family and ii converting the robust stability problem into a robust non singularity problem using kronecker operations the main contribution of the letter is to derive accurate and computationally simple optimal estimates of the robustness margin and spectral bound of general interval matrices the evaluation of the condition relies on the solutions of linear matrix inequalities lmis and eigenvalue problems both of which are solved very efficiently the improvements gained by using the proposed conditions are demonstrated through application to previous examples in the literature

stability robustness of interval matrices via lyapunov quadratic forms a sufficient condition for the robust stability of a class of interval matrices is derived using the lyapunov approach the matrices considered have elements which are nonlinear functions of a vector of independent and bounded parameters the robust stability condition requires that a quadratic form be positive definite in a finite number of conspicuous points of an enlarged parameter space

affine parameter dependent lyapunov functions and real parametric uncertainty this paper presents new tests to analyze the robust stability and or performance of linear systems with uncertain real parameters these tests are extensions of the notions of quadratic stability and performance where the fixed quadratic lyapunov function is replaced by a lyapunov function with affine dependence on the uncertain parameters admittedly with some conservatism the construction of such parameter dependent lyapunov functions can be reduced to a linear matrix inequality lmi problem and hence is numerically tractable these lmi based tests are applicable to constant or time varying uncertain parameters and are less conservative than quadratic stability in the case of slow parametric variations they also avoid the frequency sweep needed in real spl mu analysis and numerical experiments indicate that they often compare favorably with spl mu analysis for time invariant parameter uncertainty

analysis and control of differential inclusions with anti periodic conditions we deal with the optimal control of systems driven by differential inclusions with anti periodic conditions in banach spaces the operators in the differential inclusions describing the control system all depend on control variables by a solution of the control system we mean a trajectory control pair we first prove that for fixed control variables the set of solutions is non empty for the corresponding differential inclusion with anti periodic conditions we then show the functional topological properties of the set of solutions finally we investigate the existence of solutions to the optimal control problem these abstract results can be used to study optimal control systems of evolutionary hemi variational inequalities

directional stability radius a stability analysis tool for uncertain polynomial systems coefficients of characteristic polynomials for stable parametrically uncertain systems are allowed to perturb to some extent for stability stability radius is a useful tool to assess the allowance of the stability for the systems to enhance its usefulness we modify stability radius so that it takes into account of given restricted perturbations which we call directional stability radius for an application we show shifted hurwitz stability conditions and a stability analysis method for interval polynomial systems using the directional stability radii

a stabilization algorithm for a class of uncertain linear systems abstract this paper presents an algorithm for the stabilization of a class of uncertain linear systems the uncertain systems under consideration are described by state equations which depend on time varying unknown but bounded uncertain parameters the construction of the stabilizing controller involves solving a certain algebraic riccati equation furthermore the solution to this riccati equation defines a quadratic lyapunov function which is used to establish the stability of the closed loop system this leads to a notion of quadratic stabilizability it is shown that the stabilization procedure will succeed if and only if the given uncertain linear system is quadratically stabilizable the paper also deals with a notion of overbounding for uncertain linear systems this procedure enables the stabilization algorithm to be applied to a larger class of uncertain linear systems also included in the paper are results which indicate the degree of conservativeness introduced by this overbounding process

zonotopic guaranteed state estimation for uncertain systems this paper presents a new approach for guaranteed state estimation based on zonotopes for linear discrete time multivariable systems with interval multiplicative uncertainties in the presence of bounded state perturbations and noises at each sample time the presented approach computes a zonotope which contains the real system state a p radius based criterion is minimized in order to decrease the size of the zonotope at each sample time and to obtain an increasingly accurate state estimation the proposed approach allows one to efficiently handle the trade off between the complexity of the computation and the accuracy of the estimation an illustrative example is analyzed in order to highlight the advantages of the proposed state estimation technique

an efficient lmi approach for the quadratic stabilisation of a class of linear uncertain time varying systems the purpose of this article is to provide a numerically efficient method for the quadratic stabilisation of a class of linear discrete time uncertain time varying systems the considered class of systems is characterised by an interval time varying itv matrix and constant sensor and actuator matrices it is required to find a linear time invariant lti static output feedback controller yielding a quadratically stable closed loop system independently of the parameter variation rate the solvability conditions are stated in terms of linear matrix inequalities lmis the set of lmis includes the stability conditions for the feedback connection of a unique suitably defined extreme plant with an lti output controller and the positivity of a closed loop extremal matrix a consequent noticeable feature of the article is that the total number of lmis is independent of the number of uncertain parameters this greatly enhances the numerical efficiency of the design procedure

hemivariational inequality for viscoelastic contact problem with slip dependent friction abstract in this paper we consider a class of hyperbolic hemivariational inequalities modeling the frictional contact between a viscoelastic body and a rigid foundation the friction law is described by a multivalued subdifferential relation which includes the slip displacement dependent friction and the tresca models we establish the existence of weak solutions to the problem by using a surjectivity result for pseudomonotone mappings

boundary hemivariational inequality of parabolic type abstract in this paper we consider a parabolic hemivariational inequality with a nonmonotone multivalued boundary condition and with a time dependent pseudomonotone operator we establish the existence of solutions for such inequality our proof is based on a known surjectivity result for operators of pseudomonotone type we present an example of semipermeability heat conduction problem to which the result applies

quasilinear elliptic inclusions of hemivariational type extremality and compactness of the solution set abstract we consider the dirichlet boundary value problem for an elliptic inclusion governed by a quasilinear elliptic operator of leray lions type and a multivalued term which is given by the difference of clarke s generalized gradient of some locally lipschitz function and the subdifferential of some convex function problems of this kind arise e g in mechanical models described by nonconvex and nonsmooth energy functionals that result from nonmonotone multivalued constitutive laws our main goal is to characterize the solution set of the problem under consideration in particular we are going to prove that the solution set possesses extremal elements with respect to the underlying natural partial ordering of functions and that the solution set is compact the main tools used in the proofs are abstract results on pseudomonotone operators truncation and special test function techniques zorn s lemma as well as tools from nonsmooth analysis

existence results for quasilinear parabolic hemivariational inequalities abstract this paper is devoted to the periodic problem for quasilinear parabolic hemivariational inequalities at resonance as well as at nonresonance by use of the theory of multi valued pseudomonotone operators the notion of generalized gradient of clarke and the property of the first eigenfunction we build a landesman lazer theory in the nonsmooth framework of quasilinear parabolic hemivariational inequalities

multiple solutions of quasilinear periodic parabolic inclusions abstract the existence of multiple solutions for a class of quasilinear periodic parabolic boundary value problems is proved our proof is based on the one hand on the sub supersolution method for general quasilinear periodic parabolic inclusions on the other hand it relies on the construction of non overlapping ordered intervals of sub supersolutions by the use of appropriately designed quasilinear elliptic problems and the maximum and anti maximum principles our approach also allows us to provide an elementary existence proof for semilinear periodic parabolic problems which have been studied otherwise by rather involved and elaborated abstract topological tools

sub super solution method for a class of higher order evolution hemivariational inequalities abstract in this paper we extend the extremality results for the variational inequality to a higher order evolution hemivariational inequality more precisely we give an existence theorem of solution for the higher order evolution hemivariational inequality by using the sub super solution method we prove the compactness of the solution set within an order interval formed by the sub solution and super solution we also show an existence theorem of the extremal solution for the higher order evolution hemivariational inequality under consideration

effects of spectral smearing and temporal fine structure distortion on the fluctuating masker benefit for speech at a fixed signal to noise ratio normal hearing listeners receive less benefit from momentary dips in the level of a fluctuating masker for speech processed to degrade spectral detail or temporal fine structure tfs than for unprocessed speech this has been interpreted as evidence that the magnitude of the fluctuating masker benefit fmb reflects the ability to resolve spectral detail and tfs however the fmb for degraded speech is typically measured at a higher signal to noise ratio snr to yield performance similar to normal speech for the baseline stationary noise condition because the fmb decreases with increasing snr this snr difference might account for the reduction in fmb for degraded speech in this study the fmb for unprocessed and processed tfs removed or spectrally smeared speech was measured in a paradigm that adjusts word set size rather than snr to equate stationary noise performance across processing conditions compared at the same snr and percent correct level but with different set sizes processed and unprocessed stimuli yielded a similar fmb for four different fluctuating maskers speech modulated noise one opposite gender interfering talker two same gender interfering talkers and 16 hz interrupted noise these results suggest that for these maskers spectral or tfs distortions do not directly impair the ability to benefit from momentary dips in masker level

existence of anti periodic solutions for quasilinear parabolic hemivariational inequalities abstract in this paper we consider the problem of the existence of anti periodic solutions for quasilinear parabolic hemivariational inequalities with a pseudomonotone operator using regularized approximating and first eigenfunction methods and the surjectivity result we prove the existence of solutions for quasilinear parabolic hemivariational inequalities

boundary hemivariational inequality problems with doubly nonlinear operators in this paper we investigate a class of nonlinear boundary hemivariational inequality problems under suitable hypotheses the existence of solutions is established via rewriting these problems into a class of evolution inclusions and using the discretization method and the theory of pseudomonotone operators moreover the continuous dependence result of the solutions to the initial data is given

mathematical treatment of context effects in phoneme and word recognition percent recognition of phonemes and whole syllables measured in both consonant vowel consonant cvc words and cvc nonsense syllables is reported for normal young adults listening at four signal to noise s n ratios similar data are reported for the recognition of words and whole sentences in three types of sentence high predictability hp sentences with both semantic and syntactic constraints low predictability lp sentences with primarily syntactic constraints and zero predictability zp sentences with neither semantic nor syntactic constraints the probability of recognition of speech units in context pc is shown to be related to the probability of recognition without context pi by the equation pc 1 1 pi k where k is a constant the factor k is interpreted as the amount by which the channels of statistically independent information are effectively multiplied when contextual constraints are added empirical values of k are approximately 1 3 and 2 7 for word and sentence context respe

existence and regularity results for doubly nonlinear inclusions with nonmonotone perturbation abstract this paper deals with a class of nonlinear evolution inclusions arising from enthalpy formulation of heat conduction problems with phase change and nonmonotone source using time discretization technique and monotone operators theory we show the existence of weak solutions then we prove strong convergence of approximate solutions and lift regularity of the weak solutions under appropriate conditions moreover application to physical model described by hemivariational inequality is given

on stability of interval matrices new sufficient and sometimes necessary and sufficient conditions are obtained for schur and hurwitz stability of interval matrices by relying on the concept of connective stability and m matrices the necessity part is broadened to include interval matrices with mixed signs of the off diagonal elements provided the sign patterns follow that of the morishima matrix the obtained results are extended to cover convex combinations of interval matrices

signorini type variational inequality with state dependent discontinuous multi valued boundary operators abstract we consider an elliptic variational inequality of signorini type in a bounded domain r n of the form find u k and 2 u u such that a u v u s v u d 0 v k where a is a quasilinear elliptic operator in divergence form k is the nonempty closed convex set representing the thin obstacle signorini problem on s and w 1 p l p denotes the trace operator the multi valued boundary operator is generated by the multifunction s 2 s s where r r r is a function such that s r s is supposed to be locally lipschitz for all r r while r r s is allowed to be discontinuous and 2 r s stands for clarke s generalized gradient of with respect to its second argument the novelty of this paper is that the multifunction r 2 r s may discontinuously depend on r in a certain specified way which gives rise to a new class of discontinuous nonmonotone multi valued boundary operators that is rich in structure to cover a wide range of multi valued constitutive laws on the contact surface s such as e g multi valued adhesion and friction laws that are not necessarily of subdifferential type our main goal is to provide an analytical framework to prove existence enclosure and comparison results for this new class of multi valued boundary variational inequalities that includes the theory of variational hemivariational inequalities as special case

the sign definiteness lemma and its applications to robust transceiver optimization for multiuser mimo systems we formally generalize the sign definiteness lemma to the case of complex valued matrices and multiple norm bounded uncertainties this lemma has found many applications in the study of the stability of control systems and in the design and optimization of robust transceivers in communications we then present three different novel applications of this lemma in the area of multi user multiple input multiple output mimo robust transceiver optimization specifically the scenarios of interest are i robust linear beamforming in an interfering adhoc network ii robust design of a general relay network including the two way relay channel as a special case and iii a half duplex one way relay system with multiple relays for these networks we formulate the design problems of minimizing the sum mse of the symbol detection subject to different average power budget constraints we show that these design problems are non convex with bilinear or trilinear constraints and semi infinite in multiple independent uncertainty matrix valued variables we propose a two stage solution where in the first step the semi infinite constraints are converted to linear matrix inequalities using the generalized sign definiteness lemma and in the second step we use an iterative algorithm based on alternating convex search acs via simulations we evaluate the performance of the proposed scheme

diagonal stability of interval matrices and applications abstract let a i a r n n a a a be an interval matrix and 1 p we introduce the concept of schur and hurwitz diagonal stability relative to the holder p norm of a i abbreviated as sds p and hds p respectively this concept is formulated in terms of a matrix inequality using the p norm which must be satisfied by the same positive definite diagonal matrix for all a a i the inequality form is different for sds p and hds p the particular case of p 2 is equivalent to the condition of quadratic stability of a i the sds 2 inequality is equivalent to the stein inequality a a i a t pa p 0 and the hds 2 inequality is equivalent to the lyapunov inequality a a i a t p pa 0 in both cases p is a positive definite diagonal matrix and the notation 0 means negative definite the first part of the paper provides sds p and hds p criteria presents methods for finding the positive definite diagonal matrix requested by the definition of sds p and hds p analyzes the robustness of sds p and hds p and explores the connection with the schur and hurwitz stability of a i the second part shows that the sds p or hds p of a i is equivalent to the following properties of a discrete or continuous time dynamical interval system whose motion is described by a i the existence of a strong lyapunov function defined by the p norm and the existence of exponentially decreasing sets defined by the p norm that are invariant with respect to system s trajectories

consonant recognition loss in hearing impaired listeners this paper presents a compact graphical method for comparing the performance of individual hearing impaired hi listeners with that of an average normal hearing nh listener on a consonant by consonant basis this representation named the consonant loss profile clp characterizes the effect of a listener s hearing loss on each consonant over a range of performance the clp shows that the consonant loss which is the signal to noise ratio snr difference at equal nh and hi scores is consonant dependent and varies with the score this variation in the consonant loss reveals that hearing loss renders some consonants unintelligible while it reduces noise robustness of some other consonants the conventional snr loss metric snr50 defined as the snr difference at 50 recognition score is insufficient to capture this variation the snr50 value is on average 12 db lower when measured with sentences using standard clinical procedures than when measured with nonsense syllables a listener with symmetric hearing loss may not have identical clps for both ears some consonant confusions by hi listeners are influenced by the high frequency hearing loss even at a presentation level as high as 85 db sound pressure level

an lmi approach to d stability and d stabilization of linear discrete singular systems with state delay abstract the problems of d stability and d stabilization for linear discrete singular systems with state delay are addressed in this paper by using the state augmentation technique a necessary and sufficient d stability condition and a sufficient d stabilization condition for linear discrete singular time delay systems are firstly proposed then based on these conditions quadratic d stability and d stabilization conditions for linear discrete singular time delay systems with norm bounded uncertainties and interval uncertainties are obtained respectively both the d stability and d stabilization conditions are proposed in terms of linear matrix inequalities finally illustrative examples show that the proposed conditions are effective to check the d stability and to design the d stabilizing controller for linear discrete singular time delay systems

speech reception by listeners with real and simulated hearing impairment effects of continuous and interrupted noise the effects of audibility and age on masking for sentences in continuous and interrupted noise were examined in listeners with real and simulated hearing loss the absolute thresholds of each of ten listeners with sensorineural hearing loss were simulated in normal hearing listeners through a combination of spectrally shaped threshold noise and multi band expansion for octave bands with center frequencies from 0 25 8 khz each individual hearing loss was simulated in two groups of three normal hearing listeners an age matched and a non age matched group the speech to noise ratio s n for 50 correct identification of hearing in noise test hint sentences was measured in backgrounds of continuous and temporally modulated 10 hz square wave noise at two overall levels for unprocessed speech and for speech that was amplified with the nal rp prescription the s n in both continuous and interrupted noise of the hearing impaired listeners was relatively well simulated in both groups of normal hearing listeners thus release from masking the difference in s n obtained in continuous versus interrupted noise appears to be determined primarily by audibility minimal age effects were observed in this small sample observed values of masking release were compared to predictions derived from intelligibility curves generated using the extended speech intelligibility index esii rhebergen et al 2006 j acoust soc am 120 3988 3997

enclosure results for quasilinear systems of variational inequalities abstract in this paper we consider systems of quasilinear elliptic variational inequalities and prove the existence of minimal and maximal in the set theoretical sense solutions within some ordered interval of an appropriately defined pair of sub and supersolutions we show that the notion of sub and supersolutions of variational inequalities introduced here is consistent with the usual notion of sub supersolutions for variational equations for weakly coupled quasimonotone systems of variational inequalities the existence of smallest and greatest solutions is proved

evolution hemivariational inequality for a class of dynamic viscoelastic nonmonotone frictional contact problems in this paper we consider a class of hyperbolic hemivariational inequalities modeling the frictional contact between a viscoelastic body and a rigid foundation the friction condition is described by a multivalued subdifferential relation which includes both the slip displacement and the slip rate dependent friction and the tresca models the existence of weak solutions to the problem is proved by exploiting a surjectivity result for a class of pseudomonotone mappings

quadratic stability and stabilization of dynamic interval systems this note presents necessary and sufficient conditions for the quadratic stability and stabilization of dynamic interval systems the results are obtained in terms of linear matrix inequalities lmis and extended to the quadratic stability and stabilization of linear systems with uncertain parameters with the powerful lmi toolbox it is very convenient to solve these problems the illustrative examples show that this method is effective and less conservative to check the robust stability and to design the stabilizing controller for dynamic interval systems

comments on quadratic stability and stabilization of dynamic interval systems in the above paper it was claimed that the necessary and sufficient conditions for the quadratic stability and stabilization of dynamic interval systems are given in terms of linear matrix inequalities lmis in this note numerical examples are presented to show that the necessity of the conditions given in does not hold

regularity and rothe method error estimates for parabolic hemivariational inequality this paper deals with regularity of solutions to the abstract operator version of parabolic partial differential inclusion of the form u t au t j u t f t with the multivalued term given in the form of clarke subdifferential of a locally lipschitz functional j using the rothe method it is shown that under appropriate assumptions on the data the solution has the increased regularity three regularity theorems are given the first one concerns the regularity of solution in the besov space b2 1 2 0 t h the second theorem provides assumption under which the solution lies in the space h1 0 t h l 0 t v c 0 t vweak the last one shows that if the operator a is strongly monotone and the multivalued term satisfies the relaxed monotonicity assumption then the unique solution also belongs to h1 0 t v w1 0 t h in the last case the error estimates on the rothe method are also proved

a class of generalized mixed variational hemivariational inequalities i existence and uniqueness results abstract we investigate a generalized lagrange multiplier system in a banach space called a mixed variational hemivariational inequality mvhvi for short which contains a hemivariational inequality and a variational inequality first we employ the minty technique and a monotonicity argument to establish an equivalence theorem which provides three different equivalent formulations of the inequality problem without compactness for one of operators in the problem a general existence theorem for mvhvi is proved by using the fan knaster kuratowski mazurkiewicz principle combined with methods of nonsmooth analysis furthermore we demonstrate several crucial properties of the solution set to mvhvi which include boundedness convexity weak closedness and continuity finally a uniqueness result with respect to the first component of the solution for the inequality problem is proved by using the ladyzhenskaya babuska brezzi lbb condition all results are obtained in a general functional framework in reflexive banach spaces

stability robustness bounds for linear state space models with structured uncertainty in this note we consider the robust stability analysis problem in linear state space models we consider systems with structured uncertainty some lower bounds on allowable perturbations which maintain the stability of a nominally stable system are derived these bounds are shown to be less conservative than the existing ones

efficient adaptive procedures for threshold and concurrent slope estimates for psychophysics and speech intelligibility tests the minimum standard deviations achievable for concurrent estimates of thresholds and psychometric function slopes as well as the optimal target values for adaptive procedures are calculated as functions of stimulus level and track length on the basis of the binomial theory the optimum pair of targets for a concurrent estimate is found at the correct response probabilities p1 0 19 and p2 0 81 for the logistic psychometric function an adaptive procedure that converges at these optimal targets is introduced and tested with monte carlo simulations the efficiency increases rapidly when each subject s response consists of more than one statistically independent bernoulli trial sentence intelligibility tests provide more than one bernoulli trial per sentence when each word is scored separately the number of within sentence trials can be quantified by the j factor boothroyd and nittrouer j acoust soc am 84 101 114 1988 the adaptive procedure was evaluated with 10 normal hearing and 11 hearing imp

evolutionary variational hemivariational inequalities existence and comparison results we consider an evolutionary quasilinear hemivariational inequality under constraints represented by some closed and convex subset our main goal is to systematically develop the method of sub supersolution on the basis of which we then prove existence comparison compactness and extremality results the obtained results are applied to a general obstacle problem we improve the corresponding results in the recent monograph s carl v k le d motreanu nonsmooth variational problems and their inequalities comparison principles and applications springer monogr math springer new york 2007

using statistical decision theory to predict speech intelligibility iii effect of audibility on speech recognition sensitivity the speech recognition sensitivity srs model h musch and s buus j acoust soc am 109 2896 2909 2001 is a macroscopic model for predicting speech intelligibility the present study proposes a modification to the relation between the srs model s audibility noise variance and the signal excitation to noise excitation ratio snre in the auditory periphery the modified relation is derived from data obtained in nine studies that measured normal hearing listeners consonant recognition performance at several levels of speech spectrum shaped noise when the audibility noise variance is directly proportional to the relative power of the noise excitation in the auditory periphery the srs model yields good predictions of the data four of the nine studies also reported consonant recognition performance in various filtering conditions good predictions of these data were achieved with srs model parameters that were consistent with the model parameters fitting the speech in noise data and with the mode

dynamic hemivariational inequalities in contact mechanics abstract this paper gives a review of results on the existence and uniqueness of solutions to some mechanical contact problems the second order evolution problems with a general normal compliance response condition and a normal damped response one in viscoelasticity are discussed finally a new result for a problem which includes the slip displacement dependent friction and the tresca model is provided

phoneme recognition in vocoded maskers by normal hearing and aided hearing impaired listeners this study compared modulation benefit for phoneme recognition obtained by normal hearing nh and aided hearing impaired hi listeners consonant and vowel recognition scores were measured using nonsense syllables in the presence of a steady state noise and four vocoded speech maskers vocoded maskers were generated by modulating the steady state noise in either one or six frequency channels with the speech envelope extracted from the speech of either a single talker or a four talker babble aided hi listeners obtained lower consonant recognition scores than nh listeners in all masker conditions vowel recognition scores for aided hi listeners were comparable to nh scores except in the six channel vocoded masker conditions where they were relatively lower analysis using the extended speech intelligibility index developed by rhebergen versfeld and dreschler 2006 j acoust soc am 120 6 3988 3997 suggested that the signal to noise ratio deficit observed in aided hi listeners was largely due to uncompensated audibility loss there was no significant difference between modulation masking release obtained by nh and aided hi listeners for both consonant and vowel recognition

stabilization of linear time invariant interval systems via constant state feedback control this paper investigates the stabilization problem of linear uncertain systems via constant state feedback control the systems under consideration contain time invariant uncertain parameters whose values are unknown but bounded in given compact sets and are thus called interval systems the criterion for the asymptotic stability of the closed loop system obtained when a state feedback control is applied is that all the eigenvalues of the resulting system matrix are in the strict left half of the complex plane first the author shows that to insure an interval system stabilizable some entries of the system matrices must be sign invariant more precisely the number of the least required sign invariant entries in system matrices is equal to the system order then the author studies the stabilizability of a set of interval systems called standard systems which contain sufficient numbers of sign invariant entries in proper locations after dividing all standard systems into some subsets by the uncertainty locations the author then derives necessary and sufficient conditions under which every system in a subset is stabilizable regardless of its parameter varying bounds the conditions show that all uncertain entries in system matrices should form a particular geometrical pattern called a generalized antisymmetric stepwise configuration for an interval system satisfying the stabilizability conditions a computational control design procedure is also provided and illustrated via an example the result is further generalized for nonstandard systems via linear transformation

evaluation of context effects in sentence recognition it was investigated whether the model for context effects developed earlier by bronkhorst et al j acoust soc am 93 499 509 1993 can be applied to results of sentence tests used for the evaluation of speech recognition data for two german sentence tests that differed with respect to their semantic content were analyzed they had been obtained from normal hearing listeners using adaptive paradigms in which the signal to noise ratio was varied it appeared that the model can accurately reproduce the complete pattern of scores as a function of signal to noise ratio both sentence recognition scores and proportions of incomplete responses in addition it is shown that the model can provide a better account of the relationship between average word recognition probability pew and sentence recognition probability pw than the relationship pw pej which has been used in previous studies analysis of the relationship between j and the model parameters shows that j is nevertheless a very useful parameter especially when it is combined with the parameter j which can be derived using the equivalent relationship pw 0 l pe j where pw 0 is the probability of recognizing none of the words in the sentence these parameters not only provide complementary information on context effects present in the speech material but they also can be used to estimate the model parameters because the model can be applied to both speech and printed text an experiment was conducted in which part of the sentences was presented orthographically with 1 3 missing words the results revealed a large difference between the values of the model parameters for the two presentation modes this is probably due to the fact that with speech subjects can reduce the number of alternatives for a certain word using partial information that they have perceived i e not only using the sentence context a method for mapping model parameters from one mode to the other is suggested but the validity of this approach has to be confirmed with additional data 2002 acoustical society of america

within consonant perceptual differences in the hearing impaired ear the consonant recognition of 17 ears with sensorineural hearing loss is evaluated for 14 consonants p t k f s b d g v z m n under four speech weighted noise conditions 0 6 12 db snr quiet one male and one female talker were chosen for each consonant resulting in 28 total consonant vowel test tokens for a given consonant tokens by different talkers were observed to systematically differ in both the robustness to noise and or the resulting confusion groups such within consonant token differences were observed for over 60 of the tested consonants and all hi ears only when hi responses are examined on an individual token basis does one find that the error may be limited to a small subset of tokens with confusion groups that are restricted to fewer than three confusions on average averaging different tokens of the same consonant can raise the entropy of a listener s responses i e the size of the confusion group causing the listener to appear to behave in a less systematic way quantifying these token differences provides insight into hi perception of speech under noisy conditions and characterizes each listener s hearing impairment

extremal solutions of quasilinear parabolic inclusions with generalized clarke s gradient abstract in this paper we consider an initial boundary value problem for a parabolic inclusion whose multivalued nonlinearity is characterized by clarke s generalized gradient of some locally lipschitz function and whose elliptic operator may be a general quasilinear operator of leray lions type recently extremality results have been obtained in case that the governing multivalued term is of special structure such as multifunctions given by the usual subdifferential of convex functions or subgradients of so called dc functions the main goal of this paper is to prove the existence of extremal solutions within a sector of appropriately defined upper and lower solutions for quasilinear parabolic inclusions with general clarke s gradient the main tools used in the proof are abstract results on nonlinear evolution equations regularization comparison truncation and special test function techniques as well as tools from nonsmooth analysis

existence and comparison results for noncoercive and nonmonotone multivalued elliptic problems abstract we consider noncoercive quasilinear elliptic inclusions under multivalued flux boundary conditions involving multifunctions of clarke s generalized gradient our main goal is to provide existence and comparison results which are based on an appropriate generalization of the notions of subsolutions and supersolutions furthermore compactness and extremality results of the solution set enclosed by an ordered pair of sub supersolutions will be proved

a riccati equation approach to the stabilization of uncertain linear systems this paper presents a method for designing a feedback control law to stabilize a class of uncertain linear systems the systems under consideration contain uncertain parameters whose values are known only to within a given compact bounding set furthermore these uncertain parameters may be time varying the method used to establish asymptotic stability of the closed loop system obtained when the feedback control is applied involves the use of a quadratic lyapunov function the main contribution of this paper involves the development of a computationally feasible algorithm for the construction of a suitable quadratic lyapunov function once the lyapunov function has been obtained it is used to construct the stabilizing feedback control law the fundamental idea behind the algorithm presented involves constructing an upper bound for the lyapunov derivative corresponding to the closed loop system this upper bound is a quadratic form by using this upper bounding procedure a suitable lyapunov function can be found by solving a certain matrix riccati equation another major contribution of this paper is the identification of classes of systems for which the success of the algorithm is both necessary and sufficient for the existence of a suitable quadratic lyapunov function

comments regarding on stability of interval matrices with reply we note that several of the results on schur stability of interval matrices in the above paper by sezer siljak ibid vol 39 can be viewed as special cases of results obtained in a more general framework and some of the latter were previously reported in the literature in reply sezer siljak response to the issues raised in the comment

on stabilization of a new class of linear time invariant interval systems via constant state feedback control the paper is concerned with stabilization problem of a new class of linear time invariant uncertain systems via linear state feedback control we derive a necessary and sufficient condition that extends a previous result in terms of system form

necessary and sufficient conditions for the hurwitz and schur stability of interval matrices establishes a set of new sufficient conditions for the hurwitz and schur stability of interval matrices the authors use these results to establish necessary and sufficient conditions for the hurwitz and schur stability of interval matrices the authors relate the above results to the existence of quadratic lyapunov functions for linear time invariant systems with interval valued coefficient matrices using the above results the authors develop an algorithm to determine the hurwitz and the schur stability properties of interval matrices the authors demonstrate the applicability of their results by means of two specific examples

an extension of petersen s lemma on matrix uncertainty petersen s lemma on matrix uncertainty is commonly used in the analysis and design for uncertain systems with time varying norm bounded uncertain parameter in this note petersen s lemma is extended to the case where the uncertain inequality contains two uncertain matrix pairs the condition is given such that the petersen s lemma gives a necessary and sufficient condition a numerical example is given to show the effectiveness of the proposed method

importance of tonal envelope cues in chinese speech recognition recent studies have shown that temporal waveform envelope cues can provide significant information for english speech recognition this study investigated the use of temporal envelope cues in a tonal language mandarin chinese in this study the speech was divided into several frequency analysis bands the amplitude envelope was extracted from each band by half wave rectification and low pass filtering and was used to modulate a noise of the same bandwidth as the analysis band these manipulations preserved temporal and amplitude cues in each frequency band but removed the spectral detail within each band chinese vowels consonants tones and sentences were identified by 12 native chinese speaking listeners with 1 2 3 and 4 noise bands the results showed that the recognition score of vowels consonants and sentences increased monotonically with the number of bands a pattern similar to that observed in english speech recognition in contrast tones were consistently recognized at about 80 correct level independent of the number of bands this high level of tone recognition produced a significant difference in the open set sentence recognition between chinese 11 0 and english 2 9 for the one band condition where no spectral information was available the data also revealed that with primarily temporal cues the falling rising tone tone 3 and the falling tone tone 4 were more easily recognized than the flat tone tone 1 and the rising tone tone 2 this differential pattern in tone recognition resulted in a similar pattern in word recognition words having either tone 3 or 4 were more likely to be recognized while words having tone 1 and 2 were not the quantitative role of tones in chinese speech recognition was further explored using a power function model and found to play a significant role in relating phoneme recognition to sentence recognition

periodic solutions for nonlinear differential inclusions with multivalued perturbations abstract in this paper the periodic solutions for nonlinear differential inclusion governed by convex subdifferential and different perturbations are studied it is firstly proved that the differential inclusion has unique periodic solution if the perturbation function is a single valued function then by schauder s fixed point theorem and kakutani s fixed point theorem we prove that the differential inclusion has at least a periodic solution when the perturbation function is an upper semicontinuous or lower semicontinuous multifunction moreover the existence of the extremal solution for the differential inclusion is also studied finally based on one sided lipschitz osl assumption we prove the related relaxation theorem

existence and comparison principles for general quasilinear variational hemivariational inequalities we consider quasilinear elliptic variational hemivariational inequalities involving convex lower semicontinuous and locally lipschitz functionals we provide a generalization of the fundamental notion of sub and supersolutions on the basis of which we then develop the sub supersolution method for variational hemivariational inequalities including existence comparison compactness and extremality results

authors reply to comment on further enhancement on robust h control design for discrete time singular systems the original authors thank drs x ji m ren and h su for their comment on section b of the paper ibid vol 52 no 2 pp 494 499 feb 2014 indeed the original authors results for systems without uncertainties or without uncertainties in the measurement are necessary and sufficient and the proofs are correct however when in addition the uncertainties appear in the output the results are only sufficient the necessity in the latter case still an open problem even in the quadratic stability as can be seen in references 2 4 provided herein

delay dependent stabilization of stochastic interval delay systems with nonlinear disturbances in this paper a delay dependent approach is developed to deal with the robust stabilization problem for a class of stochastic time delay interval systems with nonlinear disturbances the system matrices are assumed to be uncertain within given intervals the time delays appear in both the system states and the nonlinear disturbances and the stochastic perturbation is in the form of a brownian motion the purpose of the addressed stochastic stabilization problem is to design a memoryless state feedback controller such that for all admissible interval uncertainties and nonlinear disturbances the closed loop system is asymptotically stable in the mean square where the stability criteria are dependent on the length of the time delay and therefore less conservative by using ito s differential formula and the lyapunov stability theory sufficient conditions are first derived for ensuring the stability of the stochastic interval delay systems then the controller gain is characterized in terms of the solution to a delay dependent linear matrix inequality lmi which can be easily solved by using available software packages a numerical example is exploited to demonstrate the effectiveness of the proposed design procedure

an algorithm for checking stability of symmetric interval matrices a branch and bound algorithm for checking hurwitz and schur stability of symmetric interval matrices is proposed the algorithm in a finite number of steps either verifies stability or finds a symmetric matrix which is not stable it can also be used for checking positive definiteness of asymmetric interval matrices