pitch strength of regular interval click trains with different length runs of regular intervals click trains were generated with first and second order statistics following kaernbach and demany j acoust soc am 104 2298 2306 1998 first order intervals are between successive clicks while second order intervals are those between every other click click trains were generated with a repeating alternation of fixed and random intervals which produce a pitch at the reciprocal of the duration of the fixed interval the intervals were then randomly shuffled and compared to the unshuffled alternating click trains in pitch strength comparison experiments in almost all comparisons for the first order interval stimuli the shuffled interval click trains had a stronger pitch strength than the unshuffled interval click trains the shuffled interval click trains only produced stronger pitches for second order interval stimuli when the click trains were unfiltered several experimental conditions and an analysis of runs of regular and random intervals in these click trains suggest that the auditory system is sensitive to runs of regular intervals in a stimulus that contains a mix of regular and random intervals these results indicate that fine structure regularity plays a more important role in pitch perception than randomness and that the long term autocorrelation function or spectra of these click trains are not good predictors of pitch strength

a numerical study on the solution of the cauchy problem in elasticity this work deals with the cauchy problem in two dimensional linear elasticity the equations of the problem are discretized through a standard fem approach and the resulting ill conditioned discrete problem is solved within the frame of the tikhonov approach the choice of the required regularization parameter is accomplished through the generalized cross validation criterion on this basis a numerical experimentation has been performed and the calculated solutions have been used to highlight the sensitivity to the amount of known data the noise always present in the data the regularity of boundary conditions and the choice of the regularization parameter the aim of the numerical study is to implicitly device some guidelines to be used in the solution of this kind of problems

finite element solution of two dimensional inverse elastic problems using spatial smoothing a finite element method fem is presented for calculating the surface tractions on a body from internal measurements of displacement at discrete sensor locations the solution algorithm employs a sensitivity analysis which minimizes the difference between the calculated and measured displacements at each sensor location spatial regularization is one technique employed to stabilize the minimization process by imposing various degrees of smoothness on the solution it also allows the problem to be solved with fewer sensors than traction boundary nodes as an alternative to spatial regularization a method based on keynodes is introduced which assumes that each component of the boundary traction distribution can be described by a polynomial of specified order the methods are applied to several two dimensional examples including a rolling contact problem the effects of parameters such as the number of sensors the location of the sensors and the error in the sensor displacements are discussed

finite element interval analysis of external loads identified by displacement input with uncertainty a finite element formulation is proposed for the interval estimation of the nodal forces identified by displacement input with uncertainty the stiffness matrix of the structural system in problem of linear elastic body under static loading is assumed to be known and determinate this assumption enables us to derive the governing equation of the nodal forces to be identified with respect to the nominal displacement input from the stiffness equation based on the moore penrose generalized inverse solution of the unknown remnant displacements we assume that the uncertain errors involved in the nodal displacements obtained somehow by measurement and used as input are confined in a convex hull the effect of the uncertainty on the identified nodal forces is evaluated by the sensitivity analysis of the forces with respect to the uncertain displacements how to estimate the scatter of the identified nodal forces corresponding to the uncertain displacements confined in the convex hull is devised by means of the lagrange multiplier method the validity of the proposed method for identification and interval estimation of the nodal forces is shown by the numerical example of an elastic square plate in the plane stress state and subject to in plane loading

polar codes for broadcast channels polar codes are introduced for discrete memoryless broadcast channels for m user deterministic broadcast channels polarization is applied to map uniformly random message bits from m independent messages to one codeword while satisfying broadcast constraints the polarization based codes achieve rates on the boundary of the private message capacity region for two user noisy broadcast channels polar implementations are presented for two information theoretic schemes 1 cover s superposition codes and 2 marton s codes due to the structure of polarization constraints on the auxiliary and channel input distributions are identified to ensure proper alignment of polarization indices in the multiuser setting the codes achieve rates on the capacity boundary of a few classes of broadcast channels e g binary input stochastically degraded the complexity of encoding and decoding is o n log n where n is the block length in addition polar code sequences obtain a stretched exponential decay of o 2 n beta of the average block error probability where 0 reproducible experiments for finite block lengths n 512 1024 2048 corroborate the theory

a meshless method for solving the cauchy problem in three dimensional elastostatics the application of the method of fundamental solutions to the cauchy problem in three dimensional isotropic linear elasticity is investigated the resulting system of linear algebraic equations is ill conditioned and therefore its solution is regularized by employing the first order tikhonov functional while the choice of the regularization parameter is based on the l curve method numerical results are presented for both under and equally determined cauchy problems in a piece wise smooth geometry the convergence accuracy and stability of the method with respect to increasing the number of source points and the distance between the source points and the boundary of the solution domain and decreasing the amount of noise added into the input data respectively are analysed

sound quality characteristics of refrigerator noise in real living environments with relation to psychoacoustical and autocorrelation function parameters psychoacoustical and autocorrelation function acf parameters were employed to describe the temporal fluctuations of refrigerator noise during starting transition into from the stationary phase and termination of operation the temporal fluctuations of refrigerator noise include a click at start up followed by a rapid increase in volume a change of pitch and termination of the operation subjective evaluations of the noise of 24 different refrigerators were conducted in a real living environment the relationship between objective measures and perceived noisiness was examined by multiple regression analysis sound quality indices were developed based on psychoacoustical and acf parameters the psychoacoustical parameters found to be important for evaluating noisiness in the stationary phase were loudness and roughness the relationship between noisiness and acf parameters shows that sound energy and its fluctuations are important for evaluating noisiness also refrigerator sounds that had a fluctuat

non iterative regularized mfs solution of inverse boundary value problems in linear elasticity numerical reconstruction of the missing boundary data in 2d and 3d linear elasticity noisy over prescribed data are available on the remaining accessible boundary the inverse problem is solved by a meshless method i e the method of fundamental solutions mfs stabilization is achieved via several svd based regularization methods the regularization parameter is selected via the criteria used for inverse problems the numerical reconstruction of the missing dirichlet and neumann data on an inaccessible part of the boundary in the case of two and three dimensional linear isotropic elastic materials from the knowledge of over prescribed noisy measurements taken on the remaining accessible boundary part is investigated this inverse problem is solved using the method of fundamental solutions mfs whilst its stabilization is achieved through several singular value decomposition svd based regularization methods such as the tikhonov regularization method 48 the damped svd and the truncated svd 18 the regularization parameter is selected according to the discrepancy principle 40 generalized cross validation criterion 14 and hansen s l curve method 20

iterated rippled noise discrimination at long durations iterated rippled noise irn was used to study discrimination of irn stimuli with a lower number of iterations from irn stimuli with a higher number of iterations as a function of stimulus duration 100 2000 ms such irn stimuli differ in the strength of the repetition pitch in some cases the gain used to generate irn stimuli was adjusted so that both irn stimuli in the discrimination task had the same height of the first peak in the autocorrelation function or autocorrelogram in previous work involving short duration irn stimuli 500 ms listeners were not able to discriminate between irn stimuli that had different numbers of iterations but the same height of the first peak in the autocorrelation function in the current study irn discrimination performance improved with increases in duration even in cases when the height of the first peak in the autocorrelation was the same for the two irn stimuli thus future studies involving discrimination of irn stimuli may need to use longer durations 1 s or greater than those that have been used in the past

outer bounds on the admissible source region for broadcast channels with correlated sources two outer bounds on the admissible source region for broadcast channels with correlated sources are presented the first one is strictly tighter than the existing outer bound by gohari and anantharam while the second one provides a complete characterization of the admissible source region in the case where the two sources are conditionally independent given the common part these outer bounds are deduced from the general necessary conditions established for the lossy source broadcast problem via suitable comparisons between the virtual broadcast channel induced by the source and the reconstructions and the physical broadcast channel

an achievable rate region for joint compression and dispersive information routing for networks this paper considers the problem of minimum cost communication of correlated sources over a network with multi ple sinks which consists of distributed source coding followed by routing we introduce a new routing paradigm called dispersive information routing dir wherein the intermediate nodes are allowed to split a packet and forward subsets of the received bits on each of the forward paths this paradigm opens up a rich class of research problems which focus on the interplay between encoding and routing in a network unlike conventional routing methods such as in 1 dir ensures that each sink receives just the information needed to reconstruct the sources it is required to reproduce we demonstrate using simple examples that the proposed approach offers better asymptotic performance than conventional routing techniques we show that under certain assumptions on the cost function the problem of finding the minimum cost under dir essentially reduces to characterizing an achievable rate region for a new multiterminal information theoretic setup while it is possible to derive an achievable region for this setup using prior results from general multiterminal source coding 3 these techniques do not exploit the underlying problem structure and thereby lead to suboptimal regions in this paper we propose a new coding scheme using principles from multiple descriptions encoding 2 and show that it strictly improves upon a corresponding variant of coding scheme in 3 we further show that the new coding scheme achieves the complete rate region for certain special cases of the general setup and thereby achieves the minimum communication cost under this routing paradigm

the frequency range applicable to pitch identification based upon the auto correlation function model abstract pitch identification experiments were conducted to determine the upper boundary of the frequency range within which the autocorrelation function acf model described by ando see reference 16 is applicable to the phenomenon of the missing fundamental of a complex tone pitch matching tests were conducted using 1 complex tones consisting of 2 f 3 f and 4 f where f denotes the fundamental frequencies of 0 5 1 0 1 2 1 6 2 0 or 3 0 khz and 2 complex tones consisting of 2 f and 3 f these tests showed that for both kinds of complex tones the acf model can account for the perception of pitch when the fundamental frequency is below 1200 hz

exploring the temporal mechanism involved in the pitch of unresolved harmonics this paper continues a line of research initiated by kaernbach and demany j acoust soc am 104 2298 2306 1998 who employed filtered click sequences to explore the temporal mechanism involved in the pitch of unresolved harmonics in a first experiment the just noticeable difference jnd for the fundamental frequency f0 of high pass filtered and low pass masked click trains was measured with f0 100 to 250 hz and the cut frequency 0 5 to 6 khz being varied orthogonally the data confirm the result of houtsma and smurzynski j acoust soc am 87 304 310 1990 that a pitch mechanism working on the temporal structure of the signal is responsible for analyzing frequencies higher than ten times the fundamental using high pass filtered click trains however the jnd for the temporal analysis is at 1 2 as compared to 2 3 found in studies using band pass filtered stimuli two further experiments provide evidence that the pitch of this stimulus can convey musical information a fourth experiment replicates the finding of kaernbach and demany on first and second order regularities with a cut frequency of 2 khz and extends the paradigm to binaural aperiodic click sequences the result suggests that listeners can detect first order temporal regularities in monaural click streams as well as in binaurally fused click streams

time domain galerkin method for dynamic load identification summary this paper proposes a new method called time domain galerkin method tdgm for investigating the structural dynamic load identification problems firstly the shape functions are adopted to approximate three parameters such as the dynamic load kernel function response and measured structural response secondly defining a residual function could be expressed as the difference of the measured response and the computational response thirdly select an appropriate weighting function to multiply the defined residual function and make integral operation with respect to time to be zero finally when the shape functions are chosen as the weighting function it establishes the forward model called tdgm furthermore the regularization method could have effectiveness in solving the ill posed matrix of load reconstruction and obtaining the accurate identified results of the dynamic load compared with the traditional green kernel function method gkfm tdgm can effectively overcome the influences of noise and improve the accuracy of the dynamic load identification three numerical examples are provided to demonstrate the correctness and advantages of tdgm copyright 2015 john wiley sons ltd

inverse boundary traction reconstruction with the bem abstract a boundary integral formulation is presented for the solution of the inverse elastostatics problem iesp of reconstructing missing boundary tractions in two dimensional structural members traction reconstruction may involve the determination of the location of the traction distribution in addition to its extent and amplitude the missing boundary tractions are rebuilt from measured quantities such as displacements strains or stresses these quantities may be obtained from sensors located at some internal or boundary points of the object the proposed formulation starts with an initial guess for the magnitude extent and location of the missing boundary tractions and proceeds towards the final traction distribution in a sequence of iterative steps the inverse problem is written as an optimization problem with the objective function being the sum of the squares of the differences between the measured quantities at each sensor location and the corresponding computed quantities for the assumed boundary traction distribution the constraints that the missing traction distribution lies within a certain portion of the boundary of the object are imposed this is done using the step retraction and inverse penalty function approach in which the objective function is augmented by the constraint equations using a penalty parameter the unknown traction distribution and its location are defined in terms of load and geometric parameters and the sensitivities with respect to these parameters are obtained in the boundary element framework using the implicit differentiation approach a series of numerical examples involving the reconstruction of linear parabolic and trigonometric boundary tractions respectively are solved using the present approach the effect of gaussian errors in the sensors is also studied good reconstruction of the missing boundary tractions is obtained for the examples studied the advantages of the present boundary element formulation over the corresponding finite element formulations are also outlined

a strategy to identify exciting forces acting on structures the strategy for identifying the external forces acting on structures sketched by turco comput method appl mech eng 1998 165 291 306 is extended to the dynamic case starting from the measurement of the stress or strain history in a suitable number of points of the structure the exciting forces are reconstructed this inverse problem is tackled in the frequency domain by using the standard tools of computational mechanics along with a classical approach to treat ill conditioned problems some numerical results relating to pin jointed trusses are discussed in order to validate the proposed strategy copyright 2005 john wiley sons ltd

psychophysical evidence against the autocorrelation theory of auditory temporal processing nowadays it is widely believed that the temporal structure of the auditory nerve fibers response to sound stimuli plays an important role in auditory perception an influential hypothesis is that information is extracted from this temporal structure by neural operations akin to an autocorrelation algorithm the goal of the present work was to test this hypothesis the stimuli consisted of sequences of unipolar clicks that were high pass filtered and mixed with low pass noise so as to exclude spectral cues in experiment 1 interfering clicks were inserted in an otherwise periodic isochronous click sequence each click belonging to the periodic sequence was followed after a random portion of the period by one interfering click this disrupted the detection of temporal regularity even when the interfering clicks were 5 db less intense than the periodic clicks experiments 2 4 used click sequences that showed a single peak in their autocorrelation functions for some sequences this peak originated from first order temporal regularities that is from the temporal relations between consecutive clicks for other sequences the peak originated instead from second order regularities relative to nonconsecutive clicks the detection of second order regularities appeared to be much more difficult than the detection of comparable first order regularities overall these results do not tally with the current autocorrelation models of temporal processing they suggest that the extraction of temporal information from a group of closely spaced spectral components makes no use of time intervals between nonconsecutive peaks of the amplitude envelope

experimental study of random dynamic loads identification based on weighted regularization method abstract in the identification of random dynamic loads acting on the structure it is necessary to take into account the effect of measuring error of responses and estimation error of frequency response functions frfs for this purpose a dynamic load identification model was built in which the relative error bound of the identified loads was estimated to mitigate error propagation and ill posed problem during the process of identification a weighted regularization approach based on the proper orthogonal decomposition pod was proposed where the regularization parameter was selected by the gcv method to verify the feasibility and effectiveness of this method experiments of loads identification were performed on a plate structure which was randomly excited by three electromagnetic exciters the results show a good agreement between the identified random dynamic loads and the actually exerted loads

evaluation of marton s inner bound for the general broadcast channel the best known inner bound on the two receiver general broadcast channel is due to marton however this region is not computable except in certain special cases as no bounds on the cardinality of its auxiliary random variables exist nor is it even clear that the inner bound is a closed set the main obstacle in proving cardinality bounds is the fact that the traditional use of the caratheodory theorem the main known tool for proving cardinality bounds does not yield a finite cardinality result one of the main contributions of this paper is the introduction of a new tool based on an identity that relates the second derivative of the shannon entropy of a discrete random variable under a certain perturbation to the corresponding fisher information in order to go beyond the traditional caratheodory type arguments we identify certain properties that the auxiliary random variables corresponding to the extreme points of the inner bound need to satisfy these properties are then used to establish cardinality bounds on the auxiliary random variables of the inner bound thereby proving the computability of the region and its closedness lastly we establish a conjecture of nair and zizhou that marton s inner bound and the recent outer bound of nair and el gamal do not match in general

achievable rate region for three user discrete broadcast channel based on coset codes we consider the problem of developing coding techniques and deriving achievable rate regions for discrete memoryless broadcast channels with three receivers 3 dbc we begin by identifying a novel vector additive 3 dbc for which we characterize an upper bound on the the largest achievable rate region based on unstructured codes henceforth referred to as pmb mathscr u mathcal m region we propose a coding technique based on coset codes that yield an achievable rate triple not contained within pmb mathscr u mathcal m region we generalize the proposed coding technique using a new ensemble of codes partitioned coset codes pcc containing both empirical and algebraic properties and evaluate its performance to derive an achievable rate region for the general 3 dbc the new elements in this derivation are binning and joint typicality encoding and decoding of statistically correlated pccs we validate the utility of this technique by identifying non additive instances of 3 dbc for which the proposed coding techniques based on pcc yield strictly larger rates

an integral equations method combined minimum norm solution for 3d elastostatics cauchy problem abstract in this paper we establish new density results for the equilibrium equations based on the denseness result of the elastic potential functions the cauchy problem for the equilibrium equations is investigated for this ill posed problem we construct a regularizing solution using the single layer potential function the well posedness of the regularizing solution as well as the convergence property is rigorously analyzed the advantage of the proposed scheme is that the regularizing solution is of the explicit analytic solution and therefore is easy to be implemented the method combines minimum norm solution with morozov discrepancy principle to solve an inverse problem convergence and stability estimates are then given with some examples for numerical verification on the efficiency of the proposed method the numerical convergence accuracy and stability of the method with respect to the discretisation about the integral equations on pseudo boundary and the distance between the pseudo boundary and the real boundary of the solution domain and decreasing the amount of noise added into the input data respectively are also analysed with some examples

perception of the pitch of unresolved harmonics by 3 and 7 month old human infants three month olds discriminate resolved harmonic complexes on the basis of missing fundamental mf pitch in view of reported difficulty in discriminating unresolved complexes at 7 months and striking changes in the organization of the auditory system during early infancy infants ability to discriminate unresolved complexes is of some interest this study investigated the ability of 3 month olds 7 month olds and adults to discriminate the pitch of unresolved harmonic complexes using an observer based method stimuli were mf complexes bandpass filtered with a 12 db octave slope combined in random phase presented at 70 db sound pressure level spl for 650 ms with a 50 ms rise fall with a pink noise at 65 db spl the conditions were 1 low unresolved harmonics 2500 4500 hz based on mfs of 160 and 200 hz and 2 high unresolved harmonics 4000 6000 hz based on mfs of 190 and 200 hz to demonstrate mf discrimination participants had to ignore spectral changes in complexes with the same fundamental and respond only when the fundamental changed nearly all infants tested categorized complexes by mf pitch suggesting discrimination of pitch extracted from unresolved harmonics by 3 months adults also categorized the complexes by mf pitch although musically trained adults were more successful than musically untrained adults

on the evaluation of marton s inner bound for two receiver broadcast channels marton s inner bound is the best known achievable rate region for a general two receiver discrete memoryless broadcast channel in this paper we establish improved bounds on the cardinalities of the auxiliary random variables appearing in this inner bound to the true rate region we combine a perturbation technique along with a representation using concave envelopes of information theoretic functions that involve the use of auxiliary random variables to achieve this improvement the new cardinality bounds lead to a proof that a randomized time division strategy achieves every rate triple in marton s region for binary input broadcast channels this extends the result by hajek and pursley which showed that the cover van der muelen region was exhausted by the randomized time division strategy

the method of fundamental solutions for the cauchy problem in two dimensional linear elasticity in this paper the application of the method of fundamental solutions to the cauchy problem in two dimensional isotropic linear elasticity is investigated the resulting system of linear algebraic equations is ill conditioned and therefore its solution is regularised by employing the first order tikhonov functional while the choice of the regularisation parameter is based on the l curve method numerical results are presented for both smooth and piecewise smooth geometries as well as for constant and linear stress states the convergence and the stability of the method with respect to increasing the number of source points and the distance between the source points and the boundary of the solution domain and decreasing the amount of noise added into the input data respectively are analysed

fundamental solutions method for elliptic boundary value problems we consider a procedure for solving boundary value problems for elliptic homogeneous equations known as the fundamental solutions method we prove its applicability for some second order operators as well as for fourth order ones the boundary conditions of an elliptic problem are approximated by using fundamental solutions of the corresponding operator with singularities located outside the domain of interest in a specific case of the laplacian an estimate shows that the method discussed possesses convergence properties as good as those of any method using harmonic polynomials as trial functions numerical examples are given among which are simple signorini s problems for harmonic and lame operators

achieving marton s region for broadcast channels using polar codes this paper presents polar coding schemes for the two user discrete memoryless broadcast channel dm bc which achieve marton s region with both common and private messages this is the best achievable rate region known to date and it is tight for all classes of two user dm bcs whose capacity regions are known to accomplish this task we first construct polar codes for both the superposition as well as binning strategy by combining these two schemes we obtain marton s region with private messages only finally we show how to handle the case of common information the proposed coding schemes possess the usual advantages of polar codes i e they have low encoding and decoding complexity and a superpolynomial decay rate of the error probability we follow the lead of goela abbe and gastpar who recently introduced polar codes emulating the superposition and binning schemes to align the polar indices for both schemes their solution involves some degradedness constraints that are assumed to hold between the auxiliary random variables and channel outputs to remove these constraints we consider the transmission of k blocks and employ a chaining construction that guarantees the proper alignment of the polarized indices the techniques described in this paper are quite general and they can be adopted to many other multiterminal scenarios whenever there polar indices need to be aligned

load distribution modelling for pin jointed trusses by an inverse approach the paper considers the load distribution modelling for pin jointed trusses when an approximate value of the normal stress on a suitable number of elements is known this inverse problem is formulated in the least square sense directly relating the stress on the elements with the external loads and successively solved using an iterative scheme which uses a standard decomposition method for the stiffness matrix and the conjugate direction strategy in order to obtain a regularized solution of this problem and so cut out the errors contained in the known term of the equation system the generalized cross validation criterion is used in a form suitable for iterative methods some numerical results allow an analysis of the algorithm s performance

investigation of regularization parameters and error estimating in inverse elasticity problems the method of tarantola1 based on bayesian statistical theory for solving general inverse problems is applied to inverse elasticity problems and is compared to the spatial regularization technique presented in schnur and zabaras 2 it is shown that when normal gaussian distributions are assumed and the error in the data is uncorrelated the bayesian statistical theory takes a form similar to the deterministic regularization method presented earlier in schnur and zabaras 2 as such the statistical theory can be used to provide a statistical interpretation of regularization and to estimate error in the solution of the inverse problem examples are presented to demonstrate the effect of the regularization parameters and the error in the initial data on the solution

on computing the forces from the noisy displacement data of an elastic body this study is concerned with the accurate computation of the unknown forces applied on the boundary of an elastic body using its measured displacement data with noise vision based minimally intrusive force sensing using elastically deformable grasping tools is the motivation for undertaking this problem since this problem involves incomplete and inconsistent displacement force of ail elastic body it leads to an ill posed problem known as cauchy s problem in elasticity vision based displacement measurement necessitates large displacements of the elastic body for reasonable accuracy therefore we use geometrically non linear modelling of the elastic body which was not considered by others who attempted to solve cauchy s elasticity problem before we present two methods to solve the problem the first method uses the pseudo inverse of an over constrained system of equations this method is shown to be not effective when the noise in the measured displacement data is high we attribute this to the appearance of spurious forces at regions where there should not be any forces the second method focuses on minimizing the spurious forces by varying the measured displacements within the known accuracy of the measurement technique both continuum and frame elements are used in the finite element modelling of the elastic bodies considered in the numerical examples the performance of the two methods is compared using seven numerical examples all of which show that the second method estimates the forces with an error that is not more than the noise in the measured displacements an experiment was also conducted to demonstrate the effectiveness of the second method in accurately estimating the applied forces

duality of a source coding problem and the semi deterministic broadcast channel with rate limited cooperation the wyner ahlswede korner wak empirical coordination problem where the encoders cooperate via a finite capacity one sided link is considered the coordination capacity region is derived by combining several source coding techniques such as wyner ziv coding binning and superposition coding furthermore a semi deterministic sd broadcast channel bc with one sided decoder cooperation is considered duality principles relating the two problems are presented and the capacity region for the sd bc setting is derived the direct part follows from an achievable region for a general bc that is tight for the sd scenario a converse is established by using telescoping identities the sd bc is shown to be operationally equivalent to a class of relay bcs and the correspondence between their capacity regions is established the capacity region of the sd bc is transformed into an equivalent region that is shown to be dual to the admissible region of the wak problem in the sense that the information measures defining the corner points of both regions coincide achievability and converse proofs for the equivalent region are provided for the converse we use a probabilistic construction of auxiliary random variables that depends on the distribution induced by the codebook several examples illustrate the results

on marton s inner bound and its optimality for classes of product broadcast channels marton s inner bound is the tightest known inner bound on the capacity region of the broadcast channel it is not known however if this bound is tight in general one approach to settle this key open problem in network information theory is to investigate the multiletter extension of marton s bound which is known to be tight in general this approach has become feasible only recently through the development of a new method for bounding cardinalities of auxiliary random variables by gohari and anantharam this paper undertakes this long overdue approach to establish several new results including 1 establishing the optimality of marton s bound for new classes of product broadcast channels 2 showing that the best known outer bound by nair and el gamal is not tight in general and 3 finding sufficient conditions for a global maximizer of marton s bound that imply that the 2 letter extension does not increase the achievable rate motivated by the new capacity results we establish a new outer bound on the capacity region of product broadcast channels

temporal dynamics of pitch strength in regular interval noises the pitch strength of rippled noise and iterated rippled noise has recently been fitted by an exponential function of the height of the first peak in the normalized autocorrelation function j acoust soc am 100 3329 3335 1996 the current study compares the pitch strengths and autocorrelation functions of rippled noise rn and another regular interval noise aabb rn is generated by delaying a copy of a noise sample and adding it to the undelayed version aabb with the same pitch is generated by taking a sample of noise a with the same duration as the rn delay and repeating it to produce aa and then concatenating many of these once repeated sequences to produce aabbccdd the height of the first peak h1 in the normalized autocorrelation function of aabb is 0 5 identical to that of rn the current experiments show the following 1 aabb and rn can be discriminated when the pitch is less than about 250 hz 2 for these low pitches the pitch strength of aabb is greater than that for rn

a relaxation method of an alternating iterative algorithm for the cauchy problem in linear isotropic elasticity we propose two algorithms involving the relaxation of either the given dirichlet data boundary displacements or the prescribed neumann data boundary tractions on the over specified boundary in the case of the alternating iterative algorithm of kozlov et al 16 applied to cauchy problems in linear elasticity a convergence proof of these relaxation methods is given along with a stopping criterion the numerical results obtained using these procedures in conjunction with the boundary element method bem show the numerical stability convergence consistency and computational efficiency of the proposed method

pitch of iterated rippled noise iterated rippled noise irn stimuli are generated by a cascade of delay d gain g and add networks the matched pitch of irn stimuli was determined as a function of the type of network used to generate irn stimuli the delay d 2 4 and 8 ms the number of iterations n 1 2 3 4 6 8 of the delay and add networks and whether the delayed noise was added g 1 to or subtracted g 1 from the undelayed noise the matched pitch of irn stimuli did not depend on the type of network when g 1 addition the matched pitch did not depend on the number of stages of iterations n and was always equal to the reciprocal of the delay 1 d when g 1 subtraction the match pitch depended on n when n 1 the matched pitch of irn stimuli was ambiguous having two pitches in the region of 1 d 10 when n 8 the match pitch was equal to 1 2d this change in the pitch occurred between n 2 and 6 the results are discussed in terms of spectral and temporal models of complex pitch processing a temporal model based on autocorrelation was able to provide quantitative predictions for the pitch of these irn stimuli however a spectral type of model can also account for the pitch of these irn stimuli

a boundary element strategy for elastostatic inverse problems involving uncertain boundary conditions in this paper a convenient strategy is developed to find solutions for a class of uncertain boundary value problems by the boundary element method bem such problems are ill posed but ill conditioning of the associated algebraic systems of equations can be controlled to a large extent and useful boundary data can be obtained despite ill conditioning interior data of not only sufficient quantity but also of good quality at good locations contribute to good solutions our strategy permits the condition number of the algebraic systems as a function of interior data locations to be monitored such that measured data from displacement sensors and or strain sensors at locations found to be good ones for the problem at hand can be used the present strategy is based upon the concept of a green s function library through partitioning of the bem algebraic system algebraic systems are solved using least squares via singular value decomposition svd the library idea takes advantage of modern data storage and retrieval technology and permits the process of repeated trials in order to determine good data sensor locations to be done quickly and efficiently several numerical examples are given to demonstrate the strategy some examples examine the consequences of errors in measured data copyright 1999 john wiley sons ltd

an information inequality and evaluation of marton s inner bound for binary input broadcast channels we establish an information inequality concerning five random variables this inequality is motivated by the sum rate evaluation of marton s inner bound for two receiver broadcast channels with a binary input alphabet we establish that randomized time division strategy achieves the sum rate of marton s inner bound for all binary input broadcast channels we also obtain an improved cardinality bound for evaluating the maximum sum rate given by marton s inner bound for all broadcast channels using these tools we explicitly evaluate the inner and outer bounds for the binary skew symmetric broadcast channel and demonstrate a gap between the bounds

relaxation procedures for an iterative mfs algorithm for the stable reconstruction of elastic fields from cauchy data in two dimensional isotropic linear elasticity we investigate two numerical procedures for the cauchy problem in linear elasticity involving the relaxation of either the given boundary displacements dirichlet data or the prescribed boundary tractions neumann data on the over specified boundary in the alternating iterative algorithm of kozlov et al 1991 the two mixed direct well posed problems associated with each iteration are solved using the method of fundamental solutions mfs in conjunction with the tikhonov regularization method while the optimal value of the regularization parameter is chosen via the generalized cross validation gcv criterion an efficient regularizing stopping criterion which ceases the iterative procedure at the point where the accumulation of noise becomes dominant and the errors in predicting the exact solutions increase is also presented the mfs based iterative algorithms with relaxation are tested for cauchy problems for isotropic linear elastic materials in various geometries to confirm the numerical convergence stability accuracy and computational efficiency of the proposed method

discrimination of first and second order regular intervals from random intervals as a function of high pass filter cutoff frequency this study extends the work of kaernbach and demany j acoust soc am 104 2998 2306 1998 in which regular interval stimuli ris click trains with first order intervals could be discriminated from random interval click trains but ris with second order intervals could not kaernbach and demany concluded that their results cast doubt on autocorrelation as a method of analysis for such stimuli the present study investigated the same stimuli but for a variety of filter conditions the results suggest that while ris click trains with first order intervals are more easily discriminated from random interval stimuli than second order interval ris click trains discrimination based on second order intervals is possible except when the stimuli are high pass filtered above 8 khz i e above the spectral region of phase locking

further evidence that fundamental frequency difference limens measure pitch discrimination difference limens for complex tones dlcs that differ in f0 are widely regarded as a measure of periodicity pitch discrimination however because f0 changes are inevitably accompanied by changes in the frequencies of the harmonics dlcs may actually reflect the discriminability of individual components to test this hypothesis dlcs were measured for complex tones the component frequencies of which were shifted coherently upward or downward by f 0 25 37 5 or 50 of the f0 yielding fully harmonic f 0 strongly inharmonic f 25 37 5 or odd harmonic f 50 tones if dlcs truly reflect periodicity pitch discriminability they should be larger worse for inharmonic tones than for harmonic and odd harmonic tones because inharmonic tones have a weaker pitch consistent with this prediction the results of two experiments showed a non monotonic dependence of dlcs on f with larger dlcs for f s of 25 or 37 5 than for f s of 0 or 50 of f0 these findings are consistent with

a three dimensional b spline boundary element the paper deals with the boundary element discretization of three dimensional structural problems a model based on the management of the boundary by macro elements the use of a b spline quadratic description of the boundary variables and a systematic use of analytical integration is presented by referring to rectangular piece wise solids the results of the analytical integration are given in a general form utilizable for any order polynomial shape functions the discretization process has been designed with the aim of obtaining an accurate evaluation of the stress field two numerical tests which can be compared with analytical and refined finite element solutions have been selected to check the performance of the model

on two stage sequential coding of correlated sources we study the problem of two stage sequential coding tssc which is an extension of sequential coding of correlated sources let x and y be dependent random variables the network contains two encoders and two decoders 1 a y encoder with input y 2 an x encoder with inputs x and y 3 a y decoder that reconstructs y and 4 an x decoder that reconstructs x the first stage is traditional sequential coding where the y encoder describes y to both the x decoder and y decoder and the x encoder describes x and y to the x decoder at the second stage the y encoder refines the description of y and the x encoder refines the description of x the tssc model is a theoretical abstraction of scalable video coding here y and x represent successive frames of a video sequence and the two stages together give an embedded description that allows the video to be decoded at two distinct rates we give an inner bound on the rate distortion region for this tssc model the tight bound on the rate distortion region is derived when y must be reconstructed losslessly in the usual shannon sense in the second stage we also study the minimum total rate of the tssc model and show that the minimum total rate of one stage sequential coding cannot be achieved at both stages for jointly gaussian sources this theoretical result can shed light on the rate distortion performance behavior of scalable video coding widely noted by practitioners

searching for the time constant of neural pitch extraction multichannel auditory models have been repeatedly used to explain many aspects of human pitch perception among the most successful ones are models where pitch is estimated based on an analysis of periodicity in the simulated auditory nerve firing this periodicity analysis is typically implemented as a running autocorrelation i e the autocorrelation is calculated within a temporal window which is shifted along the time axis the window was suggested to have an exponential decay with time constant estimates between 1 5 and 100 ms the window length determines the minimal integration time of pitch extraction the present experiments are designed to quantify the temporal window of pitch extraction using regular interval noises rins rins were generated by concatenating equal duration noise samples which produce a pitch corresponding to the reciprocal of the sample duration when the samples are identical periodic noise when the samples are independent the stimulus is gaussian noise and produces no pitch using rin stimuli where periodic portions interchange with aperiodic portions it is shown that the temporal window of pitch extraction cannot be modeled using a single time constant but that the size of the temporal window depends on the pitch itself

monotone measures for non local correlations non locality is the phenomenon of observing strong correlations among the outcomes of local measurements of a multipartite physical system no signaling boxes are the abstract objects for studying non locality and wirings are local operations on the space of no signaling boxes this means that no matter how non local the nature is the set of physical non local correlations must be closed under wirings then one approach to identify the non locality of nature is to characterize the closed sets of non local correlations although non trivial examples of wirings of no signaling boxes are known there is no systematic way to study wirings in particular given a set of no signaling boxes we do not know a general method to prove that it is closed under wirings in this paper we propose the first general method to construct such closed sets of non local correlations we show that a well known measure of correlation called maximal correlation when appropriately defined for non local correlations is monotonically decreasing under wirings this establishes a conjecture about the impossibility of simulating isotropic boxes from each other implying the existence of a continuum of closed sets of non local boxes under wirings to prove our main result we introduce some mathematical tools that may be of independent interest we define a notion of maximal correlation ribbon as a generalization of maximal correlation and provide a connection between it and a known object called hypercontractivity ribbon we show that these two ribbons are monotone under wirings too

boundary element solution for the cauchy problem in linear elasticity using singular value decomposition abstract in this paper the singular value decomposition svd truncated at an optimal number is analysed for obtaining approximate solutions to ill conditioned linear algebraic systems of equations which arise from the boundary element method bem discretisation of an ill posed boundary value problem in linear elasticity the regularisation parameter namely the optimal truncation number is chosen according to the discrepancy principle the numerical results obtained confirm that the svd bem produces a convergent and stable numerical solution with respect to decreasing the mesh size discretisation and the amount of noise added into the input data

perception of the low pitch of frequency shifted complexes when all of the components in a harmonic complex tone are shifted in frequency by f the pitch of the complex shifts roughly in proportion to f for tones with a small number of components the shift is usually somewhat larger than predicted from pitch theories which has been attributed to the influence of combination tones smoorenburg j acoust soc am 48 924 941 1970 experiment 1 assessed whether combination tones influence the pitch of complex tones with more than five harmonics by using noise to mask the combination tones the matching stimulus was a harmonic complex test complexes were bandpass filtered with passbands centered on harmonic numbers 5 resolved 11 intermediate or 16 unresolved and fundamental frequencies f0s were 100 200 or 400 hz for the intermediate and unresolved conditions the matching stimuli were filtered with the same passband to minimize differences in the excitation patterns of the test and matching stimuli for the resolved condition the matching st

on marton s inner bound for the general broadcast channel we establish several new results on marton s inner bound on the capacity region of the general broadcast channel inspired by the fact that marton s coding scheme without superposition coding is optimal in the gaussian case we consider the class of binary input degraded broadcast channels with no common message that have the same property we characterize this class we also establish new properties of marton s inner bound that help restrict the search space for computing the marton sum rate in particular we establish an extension of the xor case of the binary inequality of nair wang and geng

an effective algorithm for reconstructing boundary conditions in elastic solids this paper discusses the reconstruction of boundary conditions for linear elastic solids when there are not enough known boundary conditions but the stress tensor is known in a sufficient number of internal points starting with a refined boundary elements discretization of the elastic solid an iterative strategy based on the conjugate gradient method is presented this iterative strategy uses a monte carlo simulation of the generalized cross validation criterion to select the optimal solution the proposed algorithm possesses some advantages with respect to direct approaches indeed it furnishes almost as accurate results but at a low computational cost some numerical results allow an analysis of the algorithm s performance

a fast monte carlo cross validation procedure for large least squares problems with noisy data we propose a fast monte carlo algorithm for calculating reliable estimates of the trace of the influence matrixa involved in regularization of linear equations or data smoothing problems where is the regularization or smoothing parameter this general algorithm is simply as follows i generaten pseudo random valuesw 1 w n from the standard normal distribution wheren is the number of data points and letw w 1 w n t ii compute the residual vectorw a w iii take the normalized inner product w t w a w w t w as an approximation to 1 n tr i a we show both by theoretical bounds and by numerical simulations on some typical problems that the expected relative precision of these estimates is very good whenn is large enough and that they can be used in practice for the minimization with respect to of the well known generalized cross validation gcv function this permits the use of the gcv method for choosing in any particular large scale application with only a similar amount of work as the standard residual method numerical applications of this procedure to optimal spline smoothing in one or two dimensions show its efficiency

boundary element discretization of plane elasticity and plate bending problems particular attention is paid to the efficiency of the interpolation used in approximating the boundary quantities and to the precision and computational convenience in evaluating the boundary integrals the proposed discretization model is based on the use of a quadratic b spline approximation to represent the boundary variables and on the results from the analytical integration to compute the boundary coefficients

the role of the envelope in processing iterated rippled noise iterated rippled noise irn is generated by a cascade of delay and add the gain after the delay is 1 0 or delay and subtract the gain is 1 0 operations the delay and add subtract operations impart a spectral ripple and a temporal regularity to the noise the waveform fine structure is different in these two conditions but the envelope can be extremely similar four experiments were used to determine conditions in which the processing of irn stimuli might be mediated by the waveform fine structure or by the envelope in experiments 1 and 3 listeners discriminated among three stimuli in a single interval task irn stimuli generated with the delay and add operations g 1 0 irn stimuli generated using the delay and subtract operations g 1 0 and a flat spectrum noise stimulus in experiment 2 the listeners were presented two irn stimuli that differed in delay 4 vs 6 ms and a flat spectrum noise stimulus that was not an irn stimulus in experiments 1 and 2 both the envelope and waveform fine structure contained the spectral ripple and temporal regularity in experiment 3 only the envelope had this spectral and temporal structure in all experiments discrimination was determined as a function of high pass filtering the stimuli and listeners could discriminate between the two irn stimuli up to frequency regions as high as 4000 6000 hz listeners could discriminate the irn stimuli from the flat spectrum noise stimulus at even higher frequencies as high as 8000 hz but these discriminations did not appear to depend on the pitch of the irn stimuli a control experiment fourth experiment suggests that irn discriminations in high frequency regions are probably not due entirely to low frequency nonlinear distortion products the results of the paper imply that pitch processing of irn stimuli is based on the waveform fine structure