on the pressure regularity criterion of the 3d navier stokes equations abstract in the study of regularity criteria for the weak solutions of the 3d navier stokes equations an improved regularity criterion is obtained more precisely it is proved that if the pressure satisfies the critical growth condition x t l 2 2 r 0 t b r r 3 for 1 r 1 then the weak solution u x t is regular on 0 t the finding is mainly based on the innovative function decomposition methods together with besov space techniques

boosting the margin a new explanation for the effectiveness of voting methods one of the surprising recurring phenomena observed in experiments with boosting is that the test error of the generated classifier usually does not increase as its size becomes very large and often is observed to decrease even after the training error reaches zero in this paper we show that this phenomenon is related to the distribution of margins of the training examples with respect to the generated voting classification rule where the margin of an example is simply the difference between the number of correct votes and the maximum number of votes received by any incorrect label we show that techniques used in the analysis of vapnik s support vector classifiers and of neural networks with small weights can be applied to voting methods to relate the margin distribution to the test error we also show theoretically and experimentally that boosting is especially effective at increasing the margins of the training examples finally we compare our explanation to those based on the bias variance decomposition

multiple bursts multiple looks and stream coherence in the release from informational masking in the simultaneous multitone masking paradigm introduced by neff and green percept psychophys 41 409 415 1987 the masker typically is a small number of tones having frequencies and levels that are randomly drawn on every presentation large amounts of masking for a pure tone signal often occur that are thought to reflect central rather than peripheral limitations on processing previous work from this laboratory has indicated that playing a rapid succession of randomly drawn multitone maskers in each observation interval dramatically reduces the amount of masking that is observed relative to a single burst sb in this multiple bursts different mbd procedure the signal tone is the only constant frequency component during the sequence of bursts and tends to perceptually segregate from the masker in this study the number of masker bursts and the interburst interval ibi were varied the goals were to determine how the release from masking relative to the sb condition depends on the number of bursts and to examine whether increasing the ibi would cause each burst to be processed independently if the latter were true it might disrupt the perception of signal stream coherence thereby diminishing the mbd advantage however multiple independent looks could also lead to an improvement in performance for those subjects showing large amounts of informational masking in the sb condition substantial reduction in masked thresholds occurred as the number of masker bursts increased while masking increased as ibi lengthened the results were not consistent with a simple version of a multiple look model in which the information from each burst was combined optimally but instead appear to be attributable to mechanisms involved in the perceptual organization of sounds

on regularity criteria for the n dimensional navier stokes equations in terms of the pressure abstract we study the cauchy problem for the n dimensional navier stokes equations n 3 and prove some regularity criteria involving the integrability of the pressure or the pressure gradient for weak solutions in the morrey besov and multiplier spaces

generic solvability of the axisymmetric 3 d euler equations and the 2 d boussinesq equations abstract in this paper we first prove a new criterion of global solvability for smooth axisymmetric solutions of the 3 d euler equations for a cylindrical type of domain which can be whole r3 then using this result we obtain generic solvability of the equations in the cylindrical domain which does not include the axis of symmetry by a similar method we also obtain generic solvability of the 2 d boussinesq system

on some classes of nonstationary axially symmetric solutions to the navier stokes equations in the paper the navier stokes equations are studied in axially symmetric cases of nonstationary motion with rotation of incompressible viscous fluids the problem is reduced to a nonlinear system of three partial differential equations for three unknown functions of the cylindrical coordinates r and z and time t the three functions are sought in the form of power series in r with coefficients depending on t and z for the unknown coefficients recurrence relations are obtained which contain three arbitrary functions the relations are examined in three particular cases in which they give analytical solutions to the navier stokes equations for any values of the coordinates t z and r

examination of a linear model in an informational masking study when multitone maskers are used in a two interval forced choice experiment the amount of masking is larger when the masker is randomly chosen on each presentation interval compared to on each trial the same masker in the two listening intervals these conditions are referred to as having within versus between trial randomization if it is assumed that an observer s ultimate detection decision depends on a single decision variable dv it is probable that the dv s variance will be substantially larger in the within trial randomization condition compared to the between trial randomization condition the goal of the current experiment is to evaluate the degree to which this stimulus based change in dv variance can account for the difference in thresholds in the within versus between trial randomization conditions thresholds are measured for the detection of a tone added to a six component masker in between and within trial randomization conditions the slopes of the psychometric functions provide an estimate of the variance in the dv for the between and within trial randomization conditions additionally a channel model is fitted to the psychophysical results in the within trial randomization condition the resulting model is then used to predict the value of the dv for each trial and ultimately to estimate the proportion of the total variance in the within trial randomization condition that is attributable to changes in maskers across intervals the variance of the dv in the between trial randomization condition accounted for approximately 65 of the total variance in the dv in the within trial randomization condition stimulus based interval by interval masker randomization accounted for approximately 20 of the total variance of the within trial randomization dv the remaining 15 of the dv variance in the within trial randomization condition remained unaccounted for this result is fairly stable whether the maskers are drawn from a small versus large pool of potential maskers

global regularity criterion for the 3d navier stokes equations involving one entry of the velocity gradient tensor in this paper we provide a sufficient condition in terms of only one of the nine entries of the gradient tensor that is the jacobian matrix of the velocity vector field for the global regularity of strong solutions to the three dimensional navier stokes equations in the whole space as well as for the case of periodic boundary conditions

the cauchy problem for heat equations with exponential nonlinearity abstract the cauchy problem for the semilinear heat equations is studied in the orlicz space exp l 2 r n where any power behavior of interaction works as a subcritical nonlinearity we prove the existence of global solutions for the semilinear heat equations with the exponential nonlinearity under the smallness condition on the initial data in exp l 2 r n

informational masking for simultaneous nonspeech stimuli psychometric functions for fixed and randomly mixed maskers sensitivity d and response bias were measured as a function of target level for the detection of a 1000 hz tone in multitone maskers using a one interval two alternative forced choice 1i 2afc paradigm ten such maskers each with eight randomly selected components in the region 200 5000 hz with 800 1250 hz excluded to form a protected zone were presented under two conditions the fixed condition in which the same eight component masker is used throughout an experimental run and the random condition in which an eight component masker is chosen randomly trial to trial from the given set of ten such maskers differences between the results obtained with these two conditions help characterize the listener s susceptibility to informational masking im the d results show great intersubject variability but can be reasonably well fit by simple energy detector models in which internal noise and filter bandwidth are used as fitting parameters in contrast the results are not well fit by these models in addition to presentation of new data and its relation to energy detector models this paper provides comments on a variety of issues problems and research needs in the im area 2005 acoustical society of america doi 10 1121 1 2032748

regularity criterion to the axially symmetric navier stokes equations abstract smooth solutions to the axially symmetric navier stokes equations obey the following maximum principle r u r z t l r u r z 0 l we first prove the global regularity of solutions if r u r z 0 l or r u r z t l r r 0 is small compared with certain dimensionless quantity of the initial data this result improves the one in zhen lei and qi s zhang 10 as a corollary we also prove the global regularity under the assumption that r u r z t ln r 3 2 0 r 0 0 1 2

a generalized regularity criterion for 3d navier stokes equations in terms of one velocity component abstract in this article we study the global regularity of the 3d navier stokes equations in terms of one velocity component in particular we establish a new version of regularity criterion in the framework of the anisotropic lebesgue space it is a generalization of the notable work of c cao and e s titi 2011 3

liouville type theorems for the euler and the navier stokes equations abstract we prove liouville type theorems for weak solutions of the navier stokes and the euler equations in particular if the pressure satisfies p l 1 0 t l 1 r n with r n p x t d x 0 then the corresponding velocity should be trivial namely v 0 on r n 0 t in particular this is the case when p l 1 0 t h q r n where h q r n q 0 1 the hardy space on the other hand we have equipartition of energy over each component if p l 1 0 t l 1 r n with r n p x t d x 0 similar results hold also for the magnetohydrodynamic equations

existence and regularity of a class of weak solutions to the navier stokes equations abstract we construct a class of weak solutions to the navier stokes equations which have second order spatial derivatives and one order time derivatives of p power summability for 1 p 5 4 meanwhile we show that u l s 0 t w 2 r with 1 s 3 2 r 2 for 1 r 5 4 r can be relaxed not to exceed 3 2 if we consider only in the interior of in the end we extend the classical regularity theorem our results show that u is a regular solution if u l s 0 t l r with 1 s 3 2 r 1 for satisfying 1 3 with 1 s 1 r 5 6 for arbitrary domain in r 3 and 1 s 2 for r n with n 3 this result was previously obtained byh beirao da veiga chinese ann math ser b 16 1995 407 412

the small convection limit in a two dimensional chemotaxis navier stokes system this paper deals with an initial boundary value problem for the chemotaxis navier stokes system begin aligned left begin array lcll n t u cdot nabla n delta n nabla cdot n nabla c qquad quad x in omega t 0 c t u cdot nabla c delta c nc qquad quad x in omega t 0 u t kappa u cdot nabla u delta u nabla p n nabla phi qquad quad x in omega t 0 nabla cdot u 0 qquad quad x in omega t 0 end array right end aligned in a bounded convex domain omega subset mathbb r 2 with smooth boundary with kappa in mathbb r and a given smooth potential phi omega rightarrow mathbb r it is known that for each kappa in mathbb r and all sufficiently smooth initial data this problem possesses a unique global classical solution n kappa c kappa u kappa the present work asserts that these solutions stabilize to n 0 c 0 u 0 uniformly with respect to the time variable more precisely it is shown that there exist mu 0 and c 0 such that whenever kappa in 1 1 begin aligned big vert n kappa cdot t n 0 cdot t big vert l infty omega big vert c kappa cdot t c 0 cdot t big vert l infty omega quad big vert u kappa cdot t u 0 cdot t big vert l infty omega le c kappa e mu t end aligned for all t 0 this result thereby provides an example for a rigorous quantification of stability properties in the stokes limit process as frequently considered in the literature on chemotaxis fluid systems in application contexts involving low reynolds numbers

excitation based and informational masking of a tonal signal in a four tone masker this study examined contributions of peripheral excitation and informational masking to the variability in masking effectiveness observed across samples of multi tonal maskers detection thresholds were measured for a 1000 hz signal presented simultaneously with each of 25 four tone masker samples using a two interval forced choice adaptive task thresholds were measured with each sample fixed throughout trial blocks for ten listeners average thresholds differed by as much as 26 db across samples an excitation based model of partial loudness moore b c j et al 1997 j audio eng soc 45 224 237 was used to predict thresholds these predictions accounted for a significant portion of variance in the data of several listeners but no relation between the model and data was observed for many listeners moreover substantial individual differences on the order of 41 db were observed for some maskers the largest individual differences were found for maskers predicted to produce minimal excitat

a new proof of the caffarelli kohn nirenberg theorem here we give a self contained new proof of the partial regularity theorems for solutions of incompressible navier stokes equations in three spatial dimensions these results were originally due to scheffer and caffarelli kohn and nirenberg our proof is much more direct and simpler 1998 john wiley sons inc

regularity conditions of 3d navier stokes flow in terms of large spectral components abstract we develop ladyzhenskaya prodi serrin type spectral regularity criteria for 3d incompressible navier stokes equations in a torus concretely for any n 0 let w n be the sum of all spectral components of the velocity fields whose wave numbers k i n for all i 1 2 3 then we show that for any n 0 the finiteness of the serrin type norm of w n implies the regularity of the flow it implies that if the flow breaks down in a finite time the energy of the velocity fields cascades down to the arbitrarily large spectral components of w n and corresponding energy spectrum in some sense roughly decays slower than 2

two regularity criteria for the 3d mhd equations this work establishes two regularity criteria for the 3d incompressible mhd equations the first one is in terms of the derivative of the velocity field in one direction while the second one requires suitable boundedness of the derivative of the pressure in one direction

on prodi serrin type conditions for the 3d navier stokes equations abstract in this paper we prove several new prodi serrin type regularity criteria with weak lebesgue integrability in both space and time for the 3d navier stokes equations in the whole space

navier stokes equations with lower bounds on the pressure we prove that weak solutions of the three dimensional incompressible navier stokes equations are smooth if the negative part of the pressure is controlled or if the positive part of the quantity v 2 2p is controlled

individual differences in simultaneous masking with random frequency multicomponent maskers individual differences were examined for 49 listeners in a simultaneous masking task with random frequency multicomponent maskers and a 1000 hz signal across conditions the maskers were broadband noise or complexes of 2 100 sinusoids whose frequencies were randomly chosen with each presentation maskers were equal rms waveforms presented at 60 db spl thresholds for the multicomponent maskers spanned a range of up to 59 db across listeners within conditions without distinct groupings when divided into quartiles mean thresholds for listeners in the lowest quartile increased monotonically with the number of masker components and peaked below values produced by broadband noise listeners in the upper quartile had nonmonotonic functions with a broad peak around 10 20 components with values above those produced by broadband noise quiet thresholds and masked thresholds for the broadband noise masker did not distinguish high from low threshold groups lowering masker uncertainty frequencies randomized between but not within trials or introducing temporal differences by shortening the signal both improved performance by as much as 40 db dependent on the masking produced with maximum uncertainty training effects within experiment excluding an initial training period were examined for all listeners and for five listeners across two consecutive experiments eleven of forty nine listeners 22 showed systematic improvement averaging 12 db within experiment independent of high or low original thresholds for the five tested longer four improved by 5 db or more in at least one condition but the change in performance occurred primarily during initial training for the second experiment the large individual differences documented present a challenge to the development of models for masking produced by masker frequency uncertainty

solutions for semilinear parabolic equations in lp and regularity of weak solutions of the navier stokes system abstract we construct a unique local regular solution in l q 0 t l p for a class of semilinear parabolic equations which includes the semilinear heat equation u t u u u 0 and the navier stokes system here p and q are so chosen that the norm of l q 0 t l p is dimensionless or scaling invariant the main relation between p and q for the semilinear heat equation is 1 q 1 p 1 q n 2 provided that initial data are in l r with r n 2 1 where n is the space dimension applying our regular solutions to the navier stokes system we show that the k 2 dimensional hausdorff measure of possible time singularities of a turbulent solution is zero if the turbulent solution is in l q 0 t l p where k 2 q nq p p n 1 q we show moreover that a turbulent solution is regular if it is in c 0 t l n

informational masking with small set sizes informational masking refers to interference in the detectability of a sound or discrimination of some property of a sound beyond that which can be attributed to interactions at the auditory periphery in the current experiments the signal to be detected was a tone added to a 6 tone masker and informational masking was introduced by randomly choosing the frequencies of the tones that comprise the masker the primary question was whether small numbers of maskers could replace randomly drawn maskers without sacrificing the underlying detection schemes adopted by observers similar to the method used by wright and saberi j acoust soc am 105 1765 1775 1999 detection thresholds were measured for different masker set sizes where set size refers to the number of 6 tone maskers from which any one masker was drawn set sizes of 3 6 12 and 24 were tested as well as conditions in which the maskers were chosen at random in addition observers memory for maskers was coarsely evaluated large differences in thresholds were found across observers and across different masker sets even for set sizes of 24 the memory test suggests some recognition of maskers for some observers post hoc analysis of the data included an evaluation of the relative contribution of different frequencies using a single linear model as a base for comparison a linear model fitted to each condition was also evaluated although the data were fitted better using many rather than one linear model the reduction in quality of fit was modest this result suggests substantial consistency in decision strategies regardless of masker set size

on the regularity of the axisymmetric solutions of the navier stokes equations we obtain improved regularity criteria for the axisymmetric weak solutions of the three dimensional navier stokes equations with nonzero swirl in particular we prove that the integrability of single component of vorticity or velocity fields in terms of norms with zero scaling dimension give sufficient conditions for the regularity of weak solutions to obtain these criteria we derive new a priori estimates for the axisymmetric smooth solutions of the navier stokes equations

regularity of the 3d navier stokes equations with viewpoint of 2d flow abstract the regularity of 2d navier stokes flow is well known in this article we study the relationship of 3d and 2d flow and the regularity of the 3d naiver stokes equations with viewpoint of 2d equations we consider the problem in the cartesian and in the cylindrical coordinates

strategies used to detect auditory signals in small sets of random maskers detection performance for a masked auditory signal of fixed frequency can be substantially degraded if there is uncertainty about the frequency content of the masker a quasimolecular psychophysical approach was used to examine response strategies in masker uncertainty conditions and to investigate the influence of uncertainty when the number of different masker samples was limited to ten or fewer the task of the four listeners was to detect a 1000 hz signal that was presented simultaneously with one of ten ten tone masker samples the masker sample was either fixed throughout a block of two interval forced choice trials or was randomized across or within trials the primary results showed that 1 when the signal level was low and the masker sample differed between the two intervals of a trial most listeners based their responses more on the presence of specific masker samples than on the signal 2 the detrimental effect of masker uncertainty was clearly evident when only four maskers were randomly presented and grew as the size of the masker set was increased from two to ten 3 the slopes of psychometric functions measured with the same masker samples differed among the fixed and two random masker conditions 4 there were large differences in the influence of masker uncertainty across masker samples and listeners these data demonstrate the great susceptibility of human listeners to the influence of masker uncertainty and the ability of quasimolecular investigations to reveal important aspects of behavior in uncertainty condition

on 3d mhd equations with regularity in one directional derivative of the velocity abstract this work establishes a new regularity criterion for the 3d incompressible magneto hydrodynamical mhd equations in terms of one directional derivative of the velocity i e 3 u on framework of the anisotropic lebesgue spaces more precisely it is proved that if 3 u satisfies 0 t 3 u l x 3 l x 1 x 2 q d where 2 q 1 2 k 1 3 2 and 3 k 1 k 1 for some t 0 then the corresponding solution u b to the 3d mhd equations is regular on 0 t r 3

turbulence properties and global regularity of a modified navier stokes equation abstract we introduce a modification of the navier stokes equation that has the remarkable property of possessing an infinite number of conserved quantities in the inviscid limit this new equation is studied numerically and turbulence properties are analyzed concerning energy spectra and scaling of structure functions the dissipative structures arising in this new equation are curled vortex sheets instead of the vortex tubes arising in navier stokes turbulence the numerically calculated scaling of structure functions is compared with a phenomenological model based on the she leveque approach finally for this equation we demonstrate global well posedness for sufficiently smooth initial conditions in the periodic case and in r 3 the key feature is the availability of an additional estimate which shows that the l 4 norm of the velocity field remains finite

well posedness and regularity of the generalized burgers equation in periodic gevrey spaces we consider the generalized burgers equation in a class of gevrey functions g s t we show that the generalized burgers equation is well posed in this space furthermore we show that the solution is gevrey in the spacial variable and gevrey 2 in the time variable

a remark on the blow up criterion of strong solutions to the navier stokes equations abstract in this note we prove that b 1 norm of the vorticity controls the blow up phenomena of strong solutions to the navier stokes equations our criterion is a limiting case in yuan zhang 11 and an improvement of giga s result 3

additive logistic regression a statistical view of boosting boosting is one of the most important recent developments in classification methodology boosting works by sequentially applying a classification algorithm to reweighted versions of the training data and then taking a weighted majority vote of the sequence of classifiers thus produced for many classification algorithms this simple strategy results in dramatic improvements in performance we show that this seemingly mysterious phenomenon can be understood in terms of well known statistical principles namely additive modeling and maximum likelihood for the two class problem boosting can be viewed as an approximation to additive modeling on the logistic scale using maximum bernoulli likelihood as a criterion we develop more direct approximations and show that they exhibit nearly identical results to boosting direct multiclass generalizations based on multinomial likelihood are derived that exhibit performance comparable to other recently proposed multiclass generalizations of boosting in most situations and far superior in some we suggest a minor modification to boosting that can reduce computation often by factors of 10 to 50 finally we apply these insights to produce an alternative formulation of boosting decision trees this approach based on best first truncated tree induction often leads to better performance and can provide interpretable descriptions of the aggregate decision rule it is also much faster computationally making it more suitable to large scale data mining applications

regularity criteria for suitable weak solutions of the navier stokes equations near the boundary abstract we present some new regularity criteria for suitable weak solutions of the navier stokes equations near the boundary in dimension three we prove that suitable weak solutions are holder continuous up to the boundary provided that the scaled mixed norm l x t p q with 3 p 2 q 2 2 q p q 3 2 is small near the boundary our methods yield new results in the interior case as well partial regularity of weak solutions is also analyzed under some additional integral conditions

supervised projection approach for boosting classifiers in this paper we present a new approach for boosting methods for the construction of ensembles of classifiers the approach is based on using the distribution given by the weighting scheme of boosting to construct a non linear supervised projection of the original variables instead of using the weights of the instances to train the next classifier with this method we construct ensembles that are able to achieve a better generalization error and are more robust to noise presence it has been proved that adaboost method is able to improve the margin of the instances achieved by the ensemble moreover its practical success has been partially explained by this margin maximization property however in noisy problems likely to occur in real world applications the maximization of the margin of wrong instances or outliers can lead to poor generalization we propose an alternative approach where the distribution of the weights given by the boosting algorithm is used to get a supervised projection then the supervised projection is used to train the next classifier using a uniform distribution of the training instances the proposed approach is compared with three boosting techniques namely adaboost gentleboost and madaboost showing an improved performance on a large set of 55 problems from the uci machine learning repository and less sensitiveness to noise in the class labels the behavior of the proposed algorithm in terms of margin distribution and bias variance decomposition is also studied

boosting as a regularized path to a maximum margin classifier in this paper we study boosting methods from a new perspective we build on recent work by efron et al to show that boosting approximately and in some cases exactly minimizes its loss criterion with an l1 constraint on the coefficient vector this helps understand the success of boosting with early stopping as regularized fitting of the loss criterion for the two most commonly used criteria exponential and binomial log likelihood we further show that as the constraint is relaxed or equivalently as the boosting iterations proceed the solution converges in the separable case to an l1 optimal separating hyper plane we prove that this l1 optimal separating hyper plane has the property of maximizing the minimal l1 margin of the training data as defined in the boosting literature an interesting fundamental similarity between boosting and kernel support vector machines emerges as both can be described as methods for regularized optimization in high dimensional predictor space using a computational trick to make the calculation practical and converging to margin maximizing solutions while this statement describes svms exactly it applies to boosting only approximately

spectral weights in profile listening the coss analysis suggested by berg b g berg j acoust soc am 86 1743 1746 1989 is applied to a profile listening task the listener s task is to detect an increment in the level of the middle component of an n component spectrum the overall level of the components is randomly selected from a 20 db range on each presentation thus the detection task is essentially one of detecting a change in spectral shape to implement the coss analysis a small perturbation in level is added to each component of the complex coss functions are generated from these perturbations and the spectral weight that the listener assigns to each component is estimated data are reported for n 3 5 and 11 components and for perturbations with standard deviations of 0 5 1 and 2 db the estimated weights are similar to those derived for an optimum detector namely the level at the signal component is compared with the average level of the nonsignal components this result supports the view that profile analysis invol

abstract lp estimates for the cauchy problem with applications to the navier stokes equations in exterior domains abstract we apply an abstract perturbation theorem to derive global in time lq estimates for the cauchy problem and lq ls estimates for the nonstationary stokes equations in exterior domains this will be applied to obtain various new global in time estimates for weak solutions of the navier stokes equations

regularity criterion for solutions to the three dimensional navier stokes equations in the turbulent channel abstract in this paper we establish a regularity criterion of solutions to the incompressible navier stokes equations in three dimensional infinite channel in terms of the derivatives of the vertical component of the velocity field more precisely we show that the strong solution exists on the time interval 0 t provided that one of the following conditions holds u 3 x i l q 0 t l p 1 i 3 where p 3 1 q 3 p 2 q 1 2 3 2 p for i 1 2 and p 2 1 q 3 p 2 q 3 4 3 2 p for i 3

effective properties of multicomponent simultaneous maskers under conditions of uncertainty when more than one sinusoid is used as a masker more masking is observed than would be predicted by a simple combination of their individual effects this masking is dramatically increased when the masker components vary in frequency and intensity with each presentation these studies manipulated several masker parameters under conditions of high masker uncertainty examining the effect of excluding critical band components fixing or randomizing component amplitudes and frequencies and narrowing the frequency range of the components the signal was always a 200 ms 1000 hz sinusoid presented simultaneously with the 200 ms masker removing critical band components reduced the amount of masking but considerable masking remained that appears to be nonperipheral in origin fixing masker frequencies across the two intervals of a trial greatly reduced the masking observed whereas fixing masker amplitudes had no effect reducing the frequency range from 5000 to 2700 hz generally increased the masking obser

remarks on the regularity criteria of generalized mhd and navier stokes systems we study the regularity criteria of the three dimensional generalized magnetohydrodynamics mhd and navier stokes systems in particular we show that the regularity criteria of the generalized mhd system may be reduced to depend only on two diagonal entries of the jacobian matrix of the velocity vector field or one vorticity component and one entry of the jacobian matrix of the velocity vector field

derivative estimates for the navier stokes equations in a three dimensional region on etablit des estimations fractionnaires pour les solutions de l equation de navier stokes dans le cas d un domaine avec une limite sur laquelle les composantes des solutions s annulent la condition de limite fixee appropriee pour des ecoulements visqueux

observer weighting strategies in interaural time difference discrimination and monaural level discrimination for a multi tone complex two experiments measured listeners abilities to weight information from different components in a complex of 553 753 and 953 hz the goal was to determine whether or not the ability to adjust perceptual weights generalized across tasks weights were measured by binary logistic regression between stimulus values that were sampled from gaussian distributions and listeners responses the first task was interaural time discrimination in which listeners judged the laterality of the target component the second task was monaural level discrimination in which listeners indicated whether the level of the target component decreased or increased across two intervals for both experiments each of the three components served as the target ten listeners participated in both experiments the results showed that those individuals who adjusted perceptual weights in the interaural time experiment could also do so in the monaural level discrimination task the fact that the same individuals appeared to be analytic in both tasks is an indication that the weights measure the ability to attend to a particular region of the spectrum while ignoring other spectral regions

relative estimates of combination weights decision criteria and internal noise based on correlation coefficients a means by which relative combination weights may be determined is described for a signal detection model in which the decision variable is a weighted linear combination of several independent normally distributed random variables xi s the first theorem presents the correlation between the binary response variables signal versus no signal and the component xi the second theorem presents a parallel result for the case that additive internal noise is present thus in psychophysical experiments the relative combination weights may be obtained by correlating the observers responses and the input random variables third three numerical methods which allow the evaluation of the relative magnitude of the decision criterion and the variance of a hypothetical additive internal noise are considered

the regularity criterion for 3d navier stokes equations involving one velocity gradient component abstract in this article we establish sufficient conditions for the regularity of solutions of navier stokes equations based on one of the nine entries of the gradient tensor we improve the recent results of c s cao e s titi c s cao e s titi global regularity criterion for the 3d navier stokes equations involving one entry of the velocity gradient tensor arch ration mech anal 202 2011 919 932 and y zhou m pokorn y zhou m pokorn on the regularity of the solutions of the navier stokes equations via one velocity component nonlinearity 23 2010 1097 1107

regularity criterion of weak solutions to the 3d navier stokes equations via two velocity components abstract this paper is concerned with the regularity criterion of leray hopf weak solutions to the 3d navier stokes equations with respect to serrin type condition on two velocity filed components it is shown that the weak solution u u 1 u 2 u 3 is regular on 0 t if there exist two solution components for example u 2 and u 3 satisfying the condition u 2 u 3 l p 1 0 t l q 1 r 3 for 2 p 1 3 q 1 2 3 2 q 1

on the 3d navier stokes equations with regularity in pressure abstract in this paper we investigate the global regularity of leray hopf weak solutions to the 3d navier stokes equations in terms of pressure in particular we establish three serrin type regularity criteria in framework of the anisotropic lebesgue spaces our result can be understood as a generalization of the notable works of y zhou 2006 23 c cao and e titi 2008 5 and y zhou and m pokorn 2010 24

on partial regularity results for the navier stokes equations looking at the regularity results of scheffer respectively caffarelli kohn and nirenberg from a new point of view indicates that estimates for the pressure do not play an essential role in partial regularity results for the navier stokes equations

boosting with early stopping convergence and consistency boosting is one of the most significant advances in machine learning for classification and regression in its original and computationally flexible version boosting seeks to minimize empirically a loss function in a greedy fashion the resulting estimator takes an additive function form and is built iteratively by applying a base estimator or learner to updated samples depending on the previous iterations an unusual regularization technique early stopping is employed based on cv or a test set this paper studies numerical convergence consistency and statistical rates of convergence of boosting with early stopping when it is carried out over the linear span of a family of basis functions for general loss functions we prove the convergence of boosting s greedy optimization to the infinimum of the loss function over the linear span using the numerical convergence result we find early stopping strategies under which boosting is shown to be consistent based on i i d samples and we obtain bounds on the rates of convergence for boosting estimators simulation studies are also presented to illustrate the relevance of our theoretical results for providing insights to practical aspects of boosting as a side product these results also reveal the importance of restricting the greedy search step sizes as known in practice through the work of friedman and others moreover our results lead to a rigorous proof that for a linearly separable problem adaboost with e 0 step size becomes an l 1 margin maximizer when left to run to convergence

a logarithmic improvement of regularity criterion for the mhd equations in terms of the pressure abstract in this paper we prove a logarithmic improvement of regularity criterion only in terms of the pressure in morrey campanato spaces for the cauchy problem to the incompressible mhd equations

remarks for the axisymmetric navier stokes equations abstract we are concerned with 3 d incompressible navier stokes equations when the initial data and the domain are cylindrically symmetric we show that there exists a solution in a weighted space and certain weighted norms of vorticity of the solution remain finite if they are finite initially consequently we can estimate the growth rate of the solution both spatially and temporally

on the extension to slip boundary conditions of a bae and choe regularity criterion for the navier stokes equations the half space case abstract this note concerns the sufficient condition for regularity of solutions to the evolution navier stokes equations known in the literature as prodi serrin s condition h o bae and h j choe proved in a 1997 paper that in the whole space r 3 it is merely sufficient that two components of the velocity satisfy the above condition below we extend the result to the half space case r n under slip boundary conditions we show that it is sufficient that the velocity component parallel to the boundary enjoys the above condition flat boundary geometry is not essential as shown in a forthcoming paper in cylindrical domains prepared in collaboration with j bemelmans and j brand

regularity criteria in terms of pressure for the 3 d navier stokes equations in a generic domain we consider the 3 d navier stokes equations in the half space 3 or a bounded domain with smooth boundary or else an exterior domain with smooth boundary some new sufficient conditions on pressure or the gradient of pressure for the regularity of weak solutions to the navier stokes equations are obtained

informational masking by everyday sounds tone in noise detection is severely degraded when only a few spectral components of the noise are presented at random on each trial neff and green percept psychophys 41 409 415 1987 the elevations in threshold are attributed to uncertainty regarding the noise caused by sparse sampling of noise components informational masking is the term used to describe the result the present experiment was undertaken to determine how informational masking is affected when sparse sampling is from a set of common everyday sounds instead of noise on each presentation a different masker waveform of constant total power was synthesized from the magnitude and phase of a fixed number m of spectral components m 2 921 across blocks of trials the components were selected at random from 1 of 50 common environmental sounds e g baby crying door slamming phone ringing or 1 of 50 samples of gaussian noise masked thresholds for a 1 0 khz signal in the presence of both types of maskers were obtained using an adaptive two interval forced choice procedure results with noise replicated earlier results showing largest elevations in threshold for 10 20 sampled components results with everyday sounds showed a similar pattern with thresholds elevated above those for noise by as much as 10 db at the larger values of m the differences in masked thresholds were systematically related to differences in the ensemble variance of masker spectra as predicted by a model previously applied to noise lutfi j acoust soc am 94 748 758 1993 not predicted was the result of a subsequent trial by trial analysis in which 9 11 db less masking was observed for samples from everyday sounds rated as easily recognized by listeners the results suggest that listeners fail to exploit lawful dependencies among spectral components of everyday sounds to aid detection unless enough information is available for the sound to be easily recognized

regularity criterion for generalized newtonian fluids in bounded domains abstract the regularity of a non newtonian flow in a domain with a boundary cannot be treated easily because of the nonlinear viscosity term and the global property of the pressure a distance function was used in a previous study to obtain a strong solution in the present study using the distance function idea we obtain serrin type regularity criteria for the vorticity and the velocity with regard to non newtonian equations with shear dependent viscosity in a bounded domain

informational processing of complex sound i intensity discrimination this paper reports on some initial experiments using the sample discrimination paradigm to investigate normal hearing listeners ability to process information in complex nonspeech sounds an important feature of the sample discrimination experiment is that the value of the d i f f e r e n c e to be discriminated randomly varies from trial to trial it is this variation that yields potential information in the present study listeners heard a pair of multitone complexes or sequences on each trial the individual levels of the tones were drawn from two normal distributions differing only in mean the listener s task was to identify the sound having the higher mean tone level for an ideal observer in these experiments performance in d grows as the square root n where n is the number of tones obtained d grew more nearly as the cube root of n regardless of whether the tones were played sequentially or simultaneously or whether they were increased in number from high frequencies to low or from low frequencies to high a preliminary model is proposed in which discrimination performance depends predominantly on the information content of the sounds and is largely independent of the physical dimensions along which the sounds vary information content is defined in terms of the variance of the underlying stimulus distributions and a stimulus equivocation factor that is derived from the data based on this model transmitted information is estimated to be between 1 0 and 2 6 bits

note on prodi serrin ladyzhenskaya type regularity criteria for the navier stokes equations in this article we prove new regularity criteria of the prodi serrin ladyzhenskaya type for the cauchy problem of the three dimensional incompressible navier stokes equations our results improve the classical lr 0 t ls regularity criteria for both velocity and pressure by factors of certain negative powers of the scaling invariant norms u l 3 and u h 1 2

a regularity criterion for the solution of nematic liquid crystal flows in terms of the b 1 norm abstract in this paper we investigate the regularity criterion for the solution of nematic liquid crystal flows in three dimensions n 3 and in two dimensions n 2 we prove that the solution u d is smooth up to time t provided that there exists a positive constant e 0 0 such that i for n 3 u d l 0 t b 1 e 0 and ii for n 2 d l 0 t b 1 e 0

sample discrimination of frequency differences with distracters this study examined the effect of the type and frequency range of remote frequency distracters on sample discrimination of frequency differences sd f for baseline sd f conditions normal hearing listeners judged frequency differences between pairs of target tones drawn from gaussian frequency distributions near 2000 hz in experiment 1 the distracters were pairs of random frequency tones fixed frequency tones or noise bands with one distracter above and one below the target region three frequency separations of targets and distracters were tested none overlapping the target region effects of fixed frequency or noise band distracters were small compared to that of random frequency distracters which drove performance to near chance in experiment 2 dominance of the low frequency distracter was supported by the effects of changing distracter level by presenting only the higher or lower frequency distracter and by the pattern of weights derived from trial by trial responses performance recovered only when the lower frequency distracter was attenuated 40 50 db relative to the targets in experiment 3 all stimulus distributions were shifted 2 octaves higher in frequency the stronger influence of the distracter frequency below the target remained the results demonstrate the importance of both stimulus variability and frequency relationships in the interaction of targets and distracters for sd f

prediction games and arcing algorithms the theory behind the success of adaptive reweighting and combining algorithms arcing such as adaboost freund schapire 1996a 1997 and others in reducing generalization error has not been well understood by formulating prediction as a game where one player makes a selection from instances in the training set and the other a convex linear combination of predictors from a finite set existing arcing algorithms are shown to be algorithms for finding good game strategies the minimax theorem is an essential ingredient of the convergence proofs an arcing algorithm is described that converges to the optimal strategy a bound on the generalization error for the combined predictors in terms of their maximum error is proven that is sharper than bounds to date schapire freund bartlett and lee 1997 offered an explanation of why adaboost works in terms of its ability to produce generally high margins the empirical comparison of adaboost to the optimal arcing algorithm shows that their explanation is n

the reaction diffusion equation with lewis function and critical sobolev exponent abstract in this paper we consider the existence and asymptotic estimates of global solutions and finite time blowup of reaction diffusion equation with lewis function and critical sobolev exponent

the random subspace method for constructing decision forests much of previous attention on decision trees focuses on the splitting criteria and optimization of tree sizes the dilemma between overfitting and achieving maximum accuracy is seldom resolved a method to construct a decision tree based classifier is proposed that maintains highest accuracy on training data and improves on generalization accuracy as it grows in complexity the classifier consists of multiple trees constructed systematically by pseudorandomly selecting subsets of components of the feature vector that is trees constructed in randomly chosen subspaces the subspace method is compared to single tree classifiers and other forest construction methods by experiments on publicly available datasets where the method s superiority is demonstrated we also discuss independence between trees in a forest and relate that to the combined classification accuracy

navier stokes equations green s matrices vorticity direction and regularity up to the boundary abstract we consider the initial boundary value problem for the 3d navier stokes equations the physical domain is a bounded open set with a smooth boundary on which we assume a condition of free boundary type we show that if a suitable hypothesis on the vorticity direction is assumed then weak solutions are regular the main tool we use in the proof is an explicit representation of the velocity in terms of the vorticity by means of green s matrices

rapid and brief communication local structure based supervised feature extraction in the past few years the computer vision and pattern recognition community has witnessed the rapid growth of a new kind of feature extraction method the manifold learning methods which attempt to project the original data into a lower dimensional feature space by preserving the local neighborhood structure among them locality preserving projection lpp is one of the most promising feature extraction techniques however when lpp is applied to the classification tasks it shows some limitations such as the ignorance of the label information in this paper we propose a novel feature extraction method called locally discriminating projection ldp ldp utilizes class information to guide the procedure of feature extraction in ldp the local structure of the original data is constructed according to a certain kind of similarity between data points which takes special consideration of both the local information and the class information the similarity has several good properties which help to discover the true intrinsic structure of the data and make ldp a robust technique for the classification tasks we compare the proposed ldp approach with lpp as well as other feature extraction methods such as pca and lda on the public available data sets feret and ar experimental results suggest that ldp provides a better representation of the class information and achieves much higher recognition accuracies

determining nodes for semilinear parabolic equations we are concerned with the determination of the asymptotic behavior of strong solutions to the initial boundary value problem for general semilinear parabolic equations by the asymptotic behavior of these strong solutions on a finite set more precisely if the asymptotic behavior of the strong solution is known on a suitable finite set which is called determining nodes then the asymptotic behavior of the strong solution itself is entirely determined we prove the above property by the energy method