fixed point theorems of rothe and altman types about convex power condensing operator and application in this paper fixed point theorems of rothe and altman types about convex power condensing operator are given and applied to the differential equation of one order with integral boundary conditions in abstract space

positive solutions of nth order impulsive boundary value problems with integral boundary conditions in banach spaces abstract by using the fixed point theory for strict set contraction operator this paper investigates the existence of positive solutions for a class of n th order impulsive boundary value problems with integral boundary conditions in banach spaces moreover we offer some interesting discussion of the associated boundary value problems since the technique to deal with n th order bvp is completely different from that of previous papers the expression of the associated integral equation is simpler than that of relevant papers and upper and lower bounds for these positive solutions also are given our work is new

positive solutions of some singular m point boundary value problems at non resonance this paper investigates the existence of positive solutions for second order singular m point boundary value problems at non resonance a necessary and sufficient condition for the existence of c 0 1 as well as c 1 0 1 positive solutions is given by constructing lower and upper solutions and with the maximal theorem our nonlinearity f t x may be singular at x t 0 and or t 1

chaotic component obscured by strong periodicity in voice production system the effect of glottal aerodynamics in producing the nonlinear characteristics of voice is investigated by comparing the outputs of the asymmetric composite model and the two mass model the two mass model assumes the glottal airflow to be laminar nonviscous and incompressible in this model when the asymmetric factor is decreased from 0 65 to 0 35 only 1 1 and 1 2 modes are detectable however with the same parameters four vibratory modes 1 1 1 2 2 4 2 6 are found in the asymmetric composite model using the navier stokes equations to describe the complex aerodynamics in the glottis moreover the amplitude of the waveform is modulated by a small amplitude noiselike series the nonlinear detection method reveals that this noiselike modulation is not random but rather it is deterministic chaos this result agrees with the phenomenon often seen in voice in which the voice signal is strongly periodic but modulated by a small amplitude chaotic component the only difference between the two mass model and the composite model is in their descriptions of glottal airflow therefore the complex aerodynamic characteristics of glottal airflow could be important in generating the nonlinear dynamic behavior of voice production including bifurcation and a small amplitude chaotic component obscured by strong periodicity

bifurcations in an asymmetric vocal fold model a two mass model of vocal fold vibrations is analyzed with methods from nonlinear dynamics bifurcations are located in parameter planes of physiological interest subglottal pressure stiffness of the folds it is shown that a sufficiently large tension imbalance of the left and right vocal fold induces bifurcations to subharmonic regimes toroidal oscillations and chaos the corresponding attractors are characterized by phase portraits spectra and next maximum maps the relevance of these simulations for voice disorders such as laryngeal paralysis is discussed

positive solutions for a class of boundary value problems on time scales by obtaining intervals of the parameter l this paper is concerned with the existence and nonexistence of positive solution of the second order nonlinear dynamic equation on time scales p t x d t q t x t lw t f t x ax r a bx d r a 0 cx b dx d b 0 for t a b t where t is a time scale a 0 c 0 b 0 d 0 with a c 0 the arguments are based upon fixed point theorems in a cone

multiple sign changing solutions for fourth order m point boundary value problems abstract in this paper we study the existence and multiplicity of nontrivial solutions for the fourth order m point boundary value problems making use of the theory of the fixed point index in a cone and the leray schauder degree under general conditions on nonlinearity we prove that there exist at least six different nontrivial solutions for the fourth order m point boundary value problems furthermore if the nonlinearity is odd we obtain that there exist at least eight different nontrivial solutions

theoretical and experimental study of quasisteady flow separation within the glottis during phonation application to a modified two mass model most flow models used in numerical simulation of voiced sound production rely for the sake of simplicity upon a certain number of assumptions while most of these assumptions constitute reasonable first approximations others appear more doubtful in particular it is implicitly assumed that the air flow through the glottal channel separates from the walls at a fixed point since this assumption appears quite unrealistic and considering that the position of the separation point is an important parameter in phonation models in this paper a revised fluid mechanical description of the air flow through the glottis is proposed in which the separation point is allowed to move this theoretical model as well as the assumptions made are validated using steady and unsteady flow measurements combined with flow visualizations in order to evaluate the effective impact of the revised theory we then present an application to a simple mechanical model of the vocal cords derived from the classical two mass model as expected implementation of a moving separation point appears to be of great importance for the modeling of glottal signals it is further shown that the numerical model coupled with a more realistic description of the vocal cord collision can lead to signals surprisingly close to those observed in real speech by inverse filtering

multiple emitter location and signal parameter estimation processing the signals received on an array of sensors for the location of the emitter is of great enough interest to have been treated under many special case assumptions the general problem considers sensors with arbitrary locations and arbitrary directional characteristics gain phase polarization in a noise interference environment of arbitrary covariance matrix this report is concerned first with the multiple emitter aspect of this problem and second with the generality of solution a description is given of the multiple signal classification music algorithm which provides asymptotically unbiased estimates of 1 number of incident wavefronts present 2 directions of arrival doa or emitter locations 3 strengths and cross correlations among the incident waveforms 4 noise interference strength examples and comparisons with methods based on maximum likelihood ml and maximum entropy me as well as conventional beamforming are included an example of its use as a multiple frequency estimator operating on time series is included

a generalized multi point boundary value problem for second order ordinary differential equations let f 0 1 x r 2 r be a function satisfying caratheodory s conditions and e t l 1 0 1 let x i t j 0 1 a i b j r i 1 2 m 2 j 1 2 n 2 0 x 1 x 2 x m 2 1 0 t 1 t 2 t n 2 1 be given this paper is concerned with the problem of existence of a solution for the generalized multi point boundary value problems x t f t x t x t e t 0

nonlinear analysis of irregular animal vocalizations animal vocalizations range from almost periodic vocal fold vibration to completely atonal turbulent noise between these two extremes a variety of nonlinear dynamics such as limit cycles subharmonics biphonation and chaotic episodes have been recently observed these observations imply possible functional roles of nonlinear dynamics in animal acoustic communication nonlinear dynamics may also provide insight into the degree to which detailed features of vocalizations are under close neural control as opposed to more directly reflecting biomechanical properties of the vibrating vocal folds themselves so far nonlinear dynamical structures of animal voices have been mainly studied with spectrograms in this study the deterministic versus stochastic dvs prediction technique was used to quantify the amount of nonlinearity in three animal vocalizations macaque screams piglet screams and dog barks results showed that in vocalizations with pronounced harmonic components adult macaque screams certain piglet screams and dog barks deterministic nonlinear prediction was clearly more powerful than stochastic linear prediction the difference termed low dimensional nonlinearity measure lnm indicates the presence of a low dimensional attractor in highly irregular signals such as juvenile macaque screams piglet screams and some dog barks the detectable amount of nonlinearity was comparatively small analyzing 120 samples of dog barks it was further shown that the harmonic to noise ratio hnr was positively correlated with lnm it is concluded that nonlinear analysis is primarily useful in animal vocalizations with strong harmonic components including subharmonics and biphonation or low dimensional chaos

performance analysis of music type high resolution estimators for direction finding in correlated and coherent scenes an asymptotic analysis is presented of a class of high resolution estimators for resolving correlated and coherent plane waves in noise these estimators are in turn constructed from certain eigenvectors associated with spatially smoothed or unsmoothed covariance matrices generated from a uniform array the analysis is first carried out for the smoothed case and from this the conventional i e unsmoothed multiple signal classification music scheme follows as a special case independent of the total number of sources present in the scene the variance of the conventional music estimator along the true arrival angles is shown to be zero within a first order approximation the bias expressions in the smoothed case are used to obtain a resolution threshold for two coherent equipowered plane waves in white noise and the result is compared to the one derived by kaveh et al 1986 for two uncorrelated equipowered plane waves

eigenvalues of fourth order singular sturm liouville boundary value problems abstract in this paper by establishing a new comparison theorem and constructing upper and lower solutions some sufficient conditions of existence of positive solutions for the following nonlinear fourth order singular sturm liouville eigenvalue problem 1 p t p t u t f t u t 0 1 u 0 u 1 0 u 0 lim t 0 p t u t 0 u 1 lim t 1 p t u t 0 are established due to the schauder s fixed point theorem for large enough where 0 0 f and p can be singular at t 0 and or 1 moreover f can also be singular at u 0 in addition some peculiar cases are discussed and some further results are obtained

estimating model parameters by chaos synchronization using chaos synchronization and a proposed iterative method of parameter adaptation we precisely estimate the model parameters of chaotic systems and synchronize two chaotic systems with originally mismatching model parameters this parameter adaptation method can be applied to a spatiotemporal chaotic system with a one way coupled map lattice as a biomedical application this method is capable of estimating the asymmetric tension parameter of a vocal fold model

exact number of solutions for a class of two point boundary value problems with one dimensional p laplacian abstract in this paper exact number of solutions are obtained for the one dimensional p laplacian in a class of two point boundary value problems the interesting point is that the nonlinearity f is general form f u g u h u meanwhile some properties of the solutions are given in details the arguments are based upon a quadrature method

existence and multiplicity of solutions of a kind of fourth order boundary value problem abstract in this paper the existence and multiplicity results of the solutions are obtained for the fourth order boundary value problem u 4 t f t u t for all t 0 1 subject to u 0 u 1 u 0 u 1 0 where f is continuous the monotone operator theory and critical point theory are employed to discuss this problem respectively

multiple solutions for fourth order boundary value problem abstract in this paper we study the existence and multiplicity of nontrivial solutions for the fourth order two point boundary value problems making use of the theory of fixed point index in cone and leray schauder degree under general conditions on nonlinearity we prove that there exist at least six different nontrivial solutions for the fourth order two point boundary value problems furthermore if the nonlinearity is odd we obtain that there exist at least eight different nontrivial solutions

a new method for solving singular fourth order boundary value problems with mixed boundary conditions abstract in 1 2 3 4 5 6 7 8 it is very difficult to get reproducing kernel space of problem 1 this paper is concerned with a new algorithm for giving the analytical and approximate solutions of a class of fourth order in the new reproducing kernel space the numerical results are compared with both the exact solution and its n order derived functions in the example it is demonstrated that the new method is quite accurate and efficient for fourth order problems

a resolution measure for the music algorithm and its application to plane wave arrivals contaminated by coherent interference the authors present a deterministic approach to the resolution analysis of the music algorithm for resolving plane waved contaminated by coherent interference when ensemble average covariance matrices are used a resolution measure to describe the resolution potential of music in resolving two plane waves in noise is introduced a closed form solution for the resolution measure is given and the result is compared to the resolution threshold derived by m kaveh and a j barabell 1986 when the covariance matrices are estimated from a finite number of snapshots an approximate expression for the threshold signal to interference ratio sir is derived for the cases when sirs are large and the coherent interference and direct arrivals are well separated in spatial frequency illustrations are given using an 11 element uniform array for the cases of plane wave reflection from an infinite plane and scattering from an infinite conducting circular cylinder

necessary and sufficient conditions for the existence of quasi symmetric positive solutions of singular boundary value problem abstract this paper investigates the existence of quasi symmetric positive solutions for fourth order singular three point boundary value problem we first give definitions of quasi symmetric lower and upper solutions by constructing quasi symmetric lower and upper solutions and using the schauder fixed point theorem necessary and sufficient conditions for existence results are obtained

the existence and the uniqueness of symmetric positive solutions for a fourth order boundary value problem the purpose of this paper is to investigate the existence and the uniqueness of symmetric positive solutions for a class of fourth order boundary value problem y 4 t f t y t t 0 1 y 0 y 1 y 0 y 1 0 by using the fixed point index method we establish the existence of at least one or at least two symmetric positive solutions for the above boundary value problem further by using a fixed point theorem of general a concave operators we also present criteria which guarantee the existence and uniqueness of symmetric positive solutions for the above boundary value problem

nonlinear dynamical analysis of speech this paper reports results of the estimation of dynamical invariants namely lyapunov exponents dimension and metric entropy for speech signals two optimality criteria from dynamical systems literature namely singular value decomposition method and the redundancy method are used to reconstruct state space trajectories of speech and make observations the positive values of the largest lyapunov exponent of speech signals in the form of phoneme articulations show the average exponential divergence of nearby trajectories in the reconstructed state space the dimension of a time series is a measure of its complexity and gives bounds on the number of state space variables needed to model it it is found that most speech signals in the form of phoneme articulations are low dimensional for comparison a statistical model of a speech time series is also used to estimate the correlation dimension the second order dynamical entropy which is a lower bound of metric entropy of speech time series is found to

noise can delay and advance the collapse of spatiotemporal chaos spatiotemporal chaos on a regular ring network of excitable gray scott dynamical elements collapses to a stable asymptotic state we find that the addition of dynamical noise clearly influences the spatiotemporal pattern and the transient lifetime of spatiotemporal chaos spatially uniform noise significantly decreases the average lifetime of spatiotemporal chaos due to an enlargement of regions of local collapse for spatially inhomogeneous noise the collapse is maximally delayed at an intermediate noise level but drastically advanced for larger noise levels

modeling of chaotic vibrations in symmetric vocal folds the chaos mechanism of above range phonation was examined in symmetrically modeled vocal folds by using the traditional two mass model assumption the poincare map technique was used to display chaotic attractors this method provided an effective description of irregular vocal fold movements the power spectrum lyapunov exponent and kaplan yorke dimension were employed to describe chaotic vibrations in the vocal fold model these nonlinear dynamic analyses suggested that for the positive lyapunov exponent chaotic attractors contribute to irregular vocal fold vibrations descriptions of complicated irregular vibrations of the vocal fold yielded evidence of chaos to investigate the effects of independent parameters such as subglottal pressure coupling stiffness and phonation neutral area bifurcation diagrams based on the poincare map were discussed the results confirmed that the dynamics of the two mass model was strongly influenced by independent parameters nonlinear dynamic methods were expecte

symmetric positive solutions for p laplacian fourth order differential equations with integral boundary conditions this paper investigates the existence and multiplicity of symmetric positive solutions for a class of p laplacian fourth order differential equations with integral boundary conditions the arguments are based upon a specially constructed cone and the fixed point theory for cones the nonexistence of a positive solution is also studied

a class of two point boundary value problems we improve the results obtained by the first author in a recent paper where a problem raised by a ambrosetti h brezis and g cerami concerning the exact structure of the set of solutions for a class of two point boundary value problems was solved here we study a more general problem and get more detailed results

recurrence plot analysis of nonstationary data the understanding of curved patterns recurrence plots of the calls of the nomascus concolor western black crested gibbon and hylobates lar white handed gibbon show characteristic circular curved and hyperbolic patterns superimposed to the main temporal scale of the signal it is shown that these patterns are related to particular nonstationarities in the signal some of them can be reproduced by artificial signals like frequency modulated sinusoids and sinusoids with time divergent frequency these modulations are too faint to be resolved by conventional time frequency analysis with similar precision therefore recurrence plots act as a magnifying glass for the detection of multiple temporal scales in slightly modulated signals the detected phenomena in these acoustic signals can be explained in the biomechanical context by taking in account the role of the muscles controlling the vocal folds

positive solutions for a fourth order p laplacian boundary value problem abstract in this paper we study the existence multiplicity and uniqueness of positive solutions for the fourth order p laplacian boundary value problem u p 1 u f t u u 2 i 0 u 2 i 1 0 i 0 1 here p 0 and f c 0 1 r r r 0 based on a priori estimates achieved by utilizing properties of concave functions we use fixed point index theory to establish our main results

upper and lower solution method for fourth order four point boundary value problems this paper is concerned with the fourth order ordinary differential equation u 4 t f t u t u t 0 0 some new existence results are obtained by developing the upper and lower solution method and the monotone iterative technique

the upper and lower solution method for a class of singular nonlinear second order three point boundary value problems in this paper we develop the upper and lower solution method and the monotone iterative technique for a class of singular nonlinear second order three point boundary value problems a maximum principle is established and some new existence results are obtained

the statistical performance of the music and the minimum norm algorithms in resolving plane waves in noise this paper presents an asymptotic statistical analysis of the null spectra of two eigen assisted methods music 1 and minimum norm 2 for resolving independent closely spaced plane waves in noise particular attention is paid to the average deviation of the null spectra from zero at the true angles of arrival for the plane waves these deviations are expressed as functions of signal to noise ratios number of array elements angular separation of emitters and the number of snapshots in the case of music an approximate expression is derived for the resolution threshold of two plane waves with equal power in noise this result is validated by monte carlo simulations

existence and nonexistence results of impulsive first order problem with integral boundary condition abstract this paper is concerned with a first order impulsive boundary value problem ibvp for short with integral boundary condition and depending on a parameter we obtain the existence and nonexistence results of positive solutions for the ibvp when the nonlinear term and the impulses satisfy different requirements of superlinearity and sublinearity and the parameter lies in some intervals

existence and multiplicity of solutions for fourth order boundary value problems with parameters abstract in this paper we study the existence and multiplicity of the solutions for the fourth order boundary value problem bvp u 4 t u t u t f t u t 0 t 1 u 0 u 1 u 0 u 1 0 where f 0 1 r r is continuous r and r are parameters by means of the idea of the decomposition of operators shown by chen w y chen a decomposition problem for operators xuebao of dongbei renmin university 1 1957 95 98 see also m krasnosel skii topological methods in the theory of nonlinear integral equations gostehizdat moscow 1956 and the critical point theory we obtain that if the pair is on the curve 2 4 satisfying 2 2 then the above bvp has at least one two three and infinitely many solutions for being in different interval respectively

positive solutions of m point boundary value problems for higher order ordinary differential equations abstract in this paper we study m point boundary value problems for higher order ordinary differential equation y 2 n t f t y t y t y 2 n 1 t 0 t 1 y 2 i 0 0 y 2 i 1 j 1 m 2 k i j y 2 i j 0 i n 1 where f is allowed to change sign and 0 0 1 2 m 2 m 1 1 we show sufficient conditions for the existence of at least two positive solutions by applying a new fixed point theorem in cones and the associated green s function in particular the second positive solutions for the above problem is not concave

robust estimation of sinusoidal signals with colored noise using decentralized processing a technique is developed for the estimation of the number of signals and their central frequencies using decentralized processing when it is known a priori that the observations consist of a finite number of sinusoidal signals corrupted by an additive colored random noise process with unknown correlations such a noise sequence may be caused by jamming from a hostile agent the authors decentralized processing scheme is one in which each sensor estimates the frequencies and their covariance matrix and sends the results to the fusion center at the fusion center since the estimates from the sensors have a mixture density that is possibly not gaussian a robust technique is utilized to combine the estimates even when the numbers of frequencies transmitted by the various sensors are identical determining corresponding frequencies from each sensor is not a straightforward task also outliers caused by line splitting or by spurious frequencies are hard to detect these problems can be resolved by two methods the so called refitting method and the ranking method algorithms for both are presented in detail

symmetric positive solutions of boundary value problems with integral boundary conditions under conditions weaker than those used by ma we establish various results on the existence and nonexistence of symmetric positive solutions to fourth order boundary value problems with integral boundary conditions the arguments are based upon a specially constructed cone and the fixed point theory in a cone our results improve and extend that obtained in h ma symmetric positive solutions for nonlocal boundary value problems of fourth order nonlinear anal 68 2008 645 651 we illustrate our results by one example which cannot be handled using the existing results

positive solutions of fourth order four point boundary value problems with p laplacian operator in this paper we consider the existence of positive solutions for the singular fourth order p laplacian equation p u t f t u t 0 t 1 with the four point boundary conditions u 0 0 u 1 au u 0 0 u 1 bu where p t t p 2t p 1 0 1 f c 0 1 0 0 may be singular at t 0 and or 1 and u 0 by using the upper and lower solution method and fixed point theorems the existence of positive solutions to the above the boundary value problem is obtained

a monotone method for constructing extremal solutions to fourth order periodic boundary value problems in this paper we describe a constructive method which yields two monotone sequences that converge uniformly to extremal solutions to the periodic boundary value problemu 4 t f t u t u t email protected 0 email protected u 0 u email protected u 0 u email protected u 0 u email protected u 0 u email protected in the presence of an upper solution b and a lower solution a with b a

symmetric positive solutions of fourth order integral bvp for an increasing homeomorphism and homomorphism with sign changing nonlinearity on time scales in this paper we consider the eigenvalue problems for fourth order integral boundary value problems on time scales for an increasing homeomorphism and homomorphism with sign changing nonlinearities by using a fixed point index theorem we give the existence of eigenvalue intervals in which there exist one symmetric positive solution to the problem an example is also given to demonstrate the main results

glottal flow through a two mass model comparison of navier stokes solutions with simplified models a new numerical model of the vocal folds is presented based on the well known two mass models of the vocal folds the two mass model is coupled to a model of glottal airflow based on the incompressible navier stokes equations glottal waves are produced using different initial glottal gaps and different subglottal pressures fundamental frequency glottal peak flow and closed phase of the glottal waves have been compared with values known from the literature the phonation threshold pressure was determined for different initial glottal gaps the phonation threshold pressure obtained using the flow model with navier stokes equations corresponds better to values determined in normal phonation than the phonation threshold pressure obtained using the flow model based on the bernoulli equation using the navier stokes equations an increase of the subglottal pressure causes the fundamental frequency and the glottal peak flow to increase whereas the fundamental frequency in the bernoulli based model does not change with increasing pressure

positive solutions for a class of boundary value problems with integral boundary conditions this paper investigates the existence and multiplicity of positive solutions for a class of nonlinear boundary value problems of fourth order differential equations with integral boundary conditions the arguments are based upon a specially constructed cone and the fixed point theory in cone the nonexistence of positive solutions is also studied

routes to spatiotemporal chaos in the rheology of nematogenic fluids with a view to understanding the rheochaos observed in recent experiments in a variety of orientable fluids we study numerically the equations of motion of the spatiotemporal evolution of the traceless symmetric order parameter of a sheared nematogenic fluid in particular we establish by decisive numerical tests that the irregular oscillatory behavior seen in a region of parameter space where the nematic is not stably flow aligning is in fact spatiotemporal chaos we outline the dynamical phase diagram of the model and study the route to the chaotic state we find that spatiotemporal chaos in this system sets in via a regime of spatiotemporal intermittency with a power law distribution of the widths of laminar regions as in h chate and p manneville phys rev lett 58 112 1987 further the evolution of the histogram of band sizes shows a growing length scale as one moves from the chaotic towards the flow aligned phase finally we suggest possible experiments in which one can observe the intriguing behaviors discussed here

searching the least value method for solving fourth order nonlinear boundary value problems this paper obtains a searching least value slv method for a class of fourth order nonlinear boundary value problems is investigated the argument is based on the reproducing kernel space w 5 0 1 the approximate solutions u n x and u n k x are uniformly convergent to the exact solution u x and u k x k 1 2 3 4 respectively numerical results are verified that the method is quite accurate and efficient for this kind of problem

second order singular boundary value problems with integral boundary conditions abstract we study the second order singular boundary value problem u f t u 0 t 0 1 u 0 0 1 u s d s u 1 0 1 u s d s sufficient conditions are obtained for the existence and uniqueness of positive solutions the dependence of positive solutions on the parameter is also studied moreover application of our theory to a special problem is discussed to prove our theorem we utilize some results from the mixed monotone operator theory

intraglottal pressure profiles for a symmetric and oblique glottis with a divergence angle of 10 degrees human phonation does not always involve symmetric motions of the two vocal folds asymmetric motions can create slanted or oblique glottal angles this study reports intraglottal pressure profiles for a plexiglas model of the larynx with a glottis having a 10 degree divergence angle and either a symmetric orientation or an oblique angle of 15 degrees for the oblique glottis one side was divergent and the other convergent the vocal fold surfaces had 14 pressure taps the minimal glottal diameter was held constant at 0 04 cm results indicated that for either the symmetric or oblique case the pressure profiles were different on the two sides of the glottis except for the symmetric geometry for a transglottal pressure of 3 cm h2o for the symmetric case flow separation created lower pressures on the side where the flow stayed attached to the wall and the largest pressure differences between the two sides of the channel were 5 6 of the transglottal pressure for the oblique case pressures were lower

upper and lower solution method for a fourth order four point boundary value problem on time scales in this work we consider a fourth order four point boundary value problem on time scales we establish criteria for the existence of a solution by developing the upper and lower solution method and the monotone iterative technique

unsteady behavior of flow in a scaled up vocal folds model measurements of the fluid flow through a scaled up model of the human glottis are presented to determine whether glottal flow may be approximated as unsteady time and space resolved velocity vector fields from digital particle image velocimetry dpiv measurements of the flow through the gap between two moving rigid walls are presented in four cases over a range of strouhal numbers 0 010 0 018 0 035 0 040 corresponding to life scale f0 of 30 58 109 and 126hz respectively at a reynolds number of 8000 it is observed that 1 glottal flow onset is delayed after glottal opening and 2 glottal flow shutoff occurs prior to closure a comparison between flow through a fully open nonmoving glottis and that through the moving vocal folds shows a marked difference in spatial structure of the glottal jet the following features of the flow are seen to exhibit strong dependence on cycle frequency a glottal exit plane velocity b volume flow c vortex shedding rates and d vortex amplitude v

the resolution threshold of music with unkown spatially colored noise in this correspondence we present a resolution analysis for the music algorithm in a spatially colored noise environment by applying wilkinson s first order perturbation theory to the colored noise term we have shown that the music spectrum estimates at spa tial frequencies of plane wave arrivals are proportional to the square of array signal to interference ratio asir and that the resolution threshold asir for a uniform array is proportional to the inverse square of normalized spatial frequency separation between two ar rivals derivations and simulations are given for the case of two equi power plane wave arrivals the presence of unknown spatially colored noise in spatial fre quency estimation of plane wave arrivals can cause significant per formance degradation for the music algorithm for signal arrivals in a spatially white noise environment a complete eigenspace sep aration between signal subspace and noise subspace can be ob tained and music spectrum exhibits infinite peaks at signal fre quencies in a spatially colored noise scn environment an eigenspace separation with such properties can be made only if the correlation structure of the scn is known a priori i for an un known scn any partitioned subspace designated as the signal sub space will include components from part of the scn and the or thogonal relation between signal direction vectors and the noisc subspace will be destroyed as a result spectral peaks in the mu sic estimator are finite and resolutions are limited in this paper spatially colored noise scn is radiation sources whose spatial correlation matrix has a nonidentity structure spa tially colored noise typically arises from sources continuously dis tributed in spatial frequency examples are cosmic noise and at mospheric noise it also arises from additive sensor noise sources when they are nonwhite with unknown correlations or when they are uncorrelated but of unequal powers mathematically scn may be represented by a matrix component q in a spatial correlation matrix r 1

multiple solutions of some boundary value problems with parameters abstract in this paper we study the existence and multiplicity of nontrivial solutions for the following second order dirichlet nonlinear boundary value problem with odd order derivative u t a u t b u t f t u t for all t 0 1 with u 0 u 1 0 where a b r 1 f c 1 0 1 r 1 r 1 by using the morse theory we impose certain conditions on f which are able to guarantee that the problem has at least one nontrivial solution two nontrivial solutions and infinitely many solutions separately

positive solutions for second order m point boundary value problems by using the schauder fixed point theorem and analysis method we establish the existence of solutions for the m point boundary value problem u t a t f u 0 u 0 0 u 1 i 1m 2kiu i b where b ki 0 i 1 2 m 2 0 b

solvability of an m point boundary value problem for second order ordinary differential equations let 0 1 r2 r be a function satisfying caratheodory s conditions and e t l1 0 1 let i 0 1 ai r all of the ai s having the same sign i 1 2 m 2 0 1 2 m 2 1 be given this paper is concerned with the problem of existence of a solution for the m point boundary value problem x t t x t x t e t t 0 1 e formula conditions for the existence of a solution for the above boundary value problem are given using the leray schauder continuation theorem

on the number of positive solutions of nonlinear systems abstract we prove that appropriate combinations of superlinearity and sublinearity of f u with respect to at zero and infinity guarantee the existence multiplicity and nonexistence of positive solutions to boundary value problems for the n dimensional system u h t f u 0 0 is defined by u u 1 u n where u u 1 u n and covers the two important cases u u and u u p 2 u p 1 our methods employ fixed point theorems in a cone

existence of positive solutions of lidstone boundary value problems abstract we show that there exists at least one positive solution for lidstone boundary value problem 1 n u 2 n t f t u t u t u 2 n 1 t 0 t 1 u 2 i 0 u 2 i 1 0 i 0 1 n 1 under some suitable conditions our proof is based upon global bifurcation techniques

music maximum likelihood and cramer rao bound the performance of the music and ml methods is studied and their statistical efficiency is analyzed the cramer rao bound crb for the estimation problems is derived and some useful properties of the crb covariance matrix are established the relationship between the music and ml estimators is investigated as well a numerical study is reported of the statistical efficiency of the music estimator for the problem of finding the directions of two plane waves using a uniform linear array an exact description of the results is included

existence and iteration of n symmetric positive solutions for a singular two point boundary value problem let n be an arbitrary natural number in this paper we consider the existence of n symmetric positive solutions and establish a corresponding iterative scheme for the two point boundary value problem w t h t f w t 0 0 t 1 w 0 w 0 0 1 w 1 0 the main tool is the monotone iterative technique here the coefficient h t is symmetric on 0 1 and may be singular at both end points t 0 and t 1

multiple solutions of some fourth order boundary value problems abstract for some fourth order boundary value problems several new existence theorems on multiple positive negative and sign changing solutions are obtained the critical point theory and the supersolution and subsolution method are employed to discuss this problem

global structure of nodal solutions for a fourth order two point boundary value problem we consider the fourth order two point boundary value problem x kx lx a t f x 0 t 1 x 0 x 1 x 0 x 1 0 where a c 0 1 0 with a t 0 on any subinterval of 0 1 f c 1 r 0 r c r r satisfies f x x 0 for all x 0 we give conditions on the constants k l and the function f x that guarantee the existence and multiplicity results of nodal solutions the proofs of our main results are based upon disconjugate operator theory and the global bifurcation techniques

a three point boundary value problem for nonlinear fourth order differential equations abstract in this paper the authors consider the nonlinear fourth order ordinary differential equation e u t g t f u 0 with the boundary conditions b u 0 u 1 u 0 u p u 1 0 some results on the existence and nonexistence of positive solutions to problem e b are obtained results on the existence of infinitely many positive solutions are also presented examples are included to demonstrate that the results are sharp

multiply sign changing solutions for fourth order nonlinear boundary value problems abstract this paper deals with the existence of sign changing solutions for the fourth order nonlinear boundary value problem u 4 f u u 0 t 1 u 0 u 1 u 0 u 1 0 where f r 2 r is a continuously odd function some conditions on f guaranteeing the existence and multiplicity of sign changing solutions are presented the existence and multiplicity conditions concern the eigenline of the associated two parameter linear eigenvalue problem the discussion is based on the fixed point index theory in cones and an anti symmetrical extension method of solution

constructive proof of existence for a class of fourth order nonlinear bvps a new existence proof of solutions for a class of fourth order nonlinear boundary value problems is proposed the proof of the main results is based on the reproducing kernel theorem it is worthwhile to point out that the method presented in this paper can be applied for the existence proof of diverse kinds of boundary conditions

symmetric positive solutions for nonlocal boundary value problems of fourth order abstract the singular fourth order nonlocal boundary value problem u t h t f t u 0 t 1 u 0 u 1 0 1 p s u s d s u 0 u 1 0 1 q s u s d s is considered under some suitable conditions concerning the first eigenvalue of the corresponding linear operator where p q l 1 0 1 h 0 1 0 is continuous symmetric on 0 1 and may be singular at t 0 and t 1 f 0 1 0 0 is continuous and f x is symmetric on 0 1 for all x 0 the existence of at least one symmetric positive solution is obtained by the application of the fixed point index in cones

positive solutions of m point boundary value problems the second order m point boundary value problem x h x f x 0 0 x 1 0 0 1 i 1m 2ai i is considered under some conditions concerning the first eigenvalue of the relevant linear operator where i 0 1 with 0 1 2 m 2 1 ai 0 with i 1m 2ai 1 h x is allowed to be singular at x 0 and x 1 the existence of positive solutions and multiple positive solutions is obtained by means of fixed point index theory similarly conclusions hold for some other m point boundary value conditions

spatio temporal analysis of irregular vocal fold oscillations biphonation due to desynchronization of spatial modes this report is on direct observation and modal analysis of irregular spatio temporal vibration patterns of vocal fold pathologies in vivo the observed oscillation patterns are described quantitatively with multiline kymograms spectral analysis and spatio temporal plots the complex spatio temporal vibration patterns are decomposed by empirical orthogonal functions into independent vibratory modes it is shown quantitatively that biphonation can be induced either by left right asymmetry or by desynchronized anterior posterior vibratory modes and the term ap anterior posterior biphonation is introduced the presented phonation examples show that for normal phonation the first two modes sufficiently explain the glottal dynamics the spatio temporal oscillation pattern associated with biphonation due to left right asymmetry can be explained by the first three modes higher order modes are required to describe the pattern for biphonation induced by anterior posterior vibrations spatial irregularity is

on positive solutions of some nonlinear fourth order beam equations abstract the existence uniqueness and multiplicity of positive solutions of the following boundary value problem is considered u 4 t f t u t 0 for 0 where 0 is a constant f 0 1 0 0 is continuous

positive solutions of fourth order nonlinear singular boundary value problems abstract we consider the existence of positive solutions for the following fourth order singular sturm liouville boundary value problem 1 p t p t u t g t f t u 0 0 t 1 1 u 0 1 u 0 0 1 u 1 1 u 1 0 2 u 0 2 lim t 0 p t u t 0 2 u 1 2 lim t 1 p t u t 0 where g p may be singular at t 0 and or 1 moreover f t x may also have singularity at x 0 the existence and multiplicity theorems of positive solutions for the fourth order singular sturm liouville boundary value problem are obtained by using the first eigenvalue of the corresponding linear problems our results significantly extend and improve many known results including singular and nonsingular cases

interpretation of biomechanical simulations of normal and chaotic vocal fold oscillations with empirical eigenfunctions empirical orthogonal eigenfunctions are extracted from biomechanical simulations of normal and chaotic vocal fold oscillations for normal phonation two dominant empirical eigenfunctions capture the vibration patterns of the folds and exhibit a 1 1 entrainment the eigenfunctions show some correspondence to theoretical low order normal modes of a simplified three dimensional elastic continuum and to the normal modes of a linearized two mass model the eigenfunctions also facilitate a physical interpretation of energy transfer mechanisms in vocal fold dynamics subharmonic regimes and chaotic oscillations are observed during simulations of a lax cover in which case at least three empirical eigenfunctions are necessary to capture the resulting vocal fold oscillations these chaotic oscillations might be understood in terms of a desynchronization of a few of the low order modes and may be related to mechanisms of creaky voice or vocal fry furthermore some of the empirical eigenfunctions captured during complex oscillations correspond to higher order normal modes described in earlier theoretical work the empirical eigenfunctions may also be useful in the design of lower order models valid over the range for which the empirical eigenfunctions remain more or less constant and may help facilitate bifurcation analyses of the biomechanical simulation

positive solutions of nonlinear three point boundary value problems abstract let a c 0 1 b c 0 1 0 let 1 t be the unique solution of the linear boundary value problem u t a t u t b t u t 0 t 0 1 u 0 0 u 1 1 we study the existence of positive solutions to the nonlinear boundary value problem u t a t u t b t u t h t f u 0 t 0 1 u 0 0 u u 1 where 0 0 and f c 0 0 we show the existence of at least one positive solution if f is either superlinear or sublinear by applying the fixed point theorem in cones

positive solutions of fourth order two point boundary value problems in this paper by using the krasnoselskii fixed point theorem we study the existence of one or multiple positive solution of the fourth order two point boundary value problem y 4 t f t y t y t y 0 y 1 y 0 y 1 0 we also give some examples to illustrate our results

triple positive solutions of three point boundary value problems for fourth order differential equations using the avery and peterson fixed point theorem we investigate the existence of three positive solutions for the fourth order three point boundary value problem u 4 t h t f t u t u t 00 0 x 1 and h t is sign changing on 0 1 the interesting point is that the nonlinear term is allowed to depend on u

positive solution for m point boundary value problems in this paper we investigate an m point boundary value problem with sign changing nonlinearity the existence of an interval of parameters which ensures the problem has at least one positive solution is determined by constructing available operator and combining the method of lower solution with the method of topology degree moreover the associated green s function for the above problem is also given