low precision a d conversion for maximum information rate in channels with memory analog to digital converters that maximize the information rate between the quantized channel output sequence and the channel input sequence are designed for discrete time channels with intersymbol interference additive noise and for independent and identically distributed signaling optimized scalar quantizers with regions achieve the full information rate of log2 bits per channel use with a transmit alphabet of size at infinite signal to noise ratio these quantizers however are not necessarily uniform quantizers low precision scalar and two dimensional analog to digital converters are designed at finite signal to noise ratio and an upper bound on the information rate is derived simulation results demonstrate the effectiveness of the designed quantizers over conventional quantizers the advantage of the new quantizers is further emphasized by an example of a channel for which a slicer with a single threshold at zero and a carefully optimized channel input with memory fail to achieve a rate of one bit per channel use at high signal to noise ratio in contrast to memoryless binary signaling and an optimized quantizer

communication on the grassmann manifold a geometric approach to the noncoherent multiple antenna channel we study the capacity of multiple antenna fading channels we focus on the scenario where the fading coefficients vary quickly thus an accurate estimation of the coefficients is generally not available to either the transmitter or the receiver we use a noncoherent block fading model proposed by marzetta and hochwald see ibid vol 45 p 139 57 1999 the model does not assume any channel side information at the receiver or at the transmitter but assumes that the coefficients remain constant for a coherence interval of length t symbol periods we compute the asymptotic capacity of this channel at high signal to noise ratio snr in terms of the coherence time t the number of transmit antennas m and the number of receive antennas n while the capacity gain of the coherent multiple antenna channel is min m n bits per second per hertz for every 3 db increase in snr the corresponding gain for the noncoherent channel turns out to be m 1 m t bits per second per hertz where m min m n t 2 the capacity expression has a geometric interpretation as sphere packing in the grassmann manifold

subblock constrained codes for real time simultaneous energy and information transfer consider an energy harvesting receiver that uses the same received signal both for decoding information and for harvesting energy which is employed to power its circuitry in the scenario where the receiver has limited battery size a signal with bursty energy content may cause power outage at the receiver since the battery will drain during intervals with low signal energy in this paper we analyze subblock energy constrained codes seccs which ensure that sufficient energy is carried within every subblock duration we consider discrete memoryless channels and characterize the secc capacity and the secc error exponent and provide useful bounds for these values we also study constant subblock composition codes csccs which are a subclass of seccs where all the subblocks in every codeword have the same fixed composition and this subblock composition is chosen to maximize the rate of information transfer while meeting the energy requirement compared with constant composition codes cccs we show that csccs incur a rate loss and that the error exponent for csccs is also related to the error exponent for cccs by the same rate loss term we exploit the symmetry in csccs to obtain a necessary and sufficient condition on the subblock length for avoiding power outage at the receiver furthermore for cscc sequences we present a tight lower bound on the average energy per symbol within a sliding time window we provide numerical examples highlighting the tradeoff between the delivery of sufficient energy to the receiver and achieving high information transfer rates it is observed that the ability to use energy in real time imposes less of penalty compared with the ability to use information in real time

an improvement to the bit stuffing algorithm the bit stuffing algorithm is a technique for coding constrained sequences by the insertion of bits into an arbitrary data sequence this approach was previously introduced and applied to d k constrained codes results show that the maximum average rate of the bit stuffing code achieves capacity when k d 1 or k spl infin while it is suboptimal for all other d k pairs furthermore this technique was generalized to produce codes with an average rate that achieves capacity for all d k pairs however this extension results in a more complicated scheme this correspondence proposes a modification to the bit stuffing algorithm that maintains its simplicity we show analytically that the proposed algorithm achieves improved average rates over bit stuffing for most d k constraints we further determine all constraints for which this scheme produces codes with an average rate equal to the shannon capacity

extensions of the i mmse relationship to gaussian channels with feedback and memory unveiling a fundamental link between information theory and estimation theory the i mmse relationship by guo et al together with its numerous extensions has great theoretical significance and various practical applications on the other hand its influences to date have been restricted to channels without feedback or memory due to the absence of its extensions to such channels in this paper we propose the extensions of the i mmse relationship to discrete time and continuous time gaussian channels with feedback and or memory our approach is based on a very simple observation which can be applied to other scenarios such as a simple and direct proof of the classical de bruijn s identity

permutation trellis codes we introduce the new concept of permutation trellis codes and present a generalized construction procedure applying our technique of distance preserving mappings minimum distance decoding follows naturally using the viterbi algorithm we furthermore investigate the performance of these codes when combined with multitone frequency shift keying modulation and noncoherent detection in a diversity scheme to make transmissions robust against narrowband broadband and background noise disturbances such as those encountered in power line communications

an advanced boundary element fast fourier transform axisymmetric formulation for acoustic radiation and wave scattering problems an advanced boundary element fast fourier transform be fft methodology for solving axisymmetric acoustic wave scattering and radiation problems with non axisymmetric boundary conditions is reported the boundary quantities of the problem are expanded in complex fourier series with respect to the circumferencial direction each of the expanding coefficients satisfies a surface integral equation which due to axisymmetry is reduced to a line integral along the surface generator of the body and an integral over the angle of revolution the first integral is evaluated through gauss quadrature by employing a two dimensional boundary element methodology the integration over the circumferencial direction is performed simultaneously for all the fourier coefficients through the fft the singular and hyper singular integrals are computed directly by employing highly accurate three dimensional integration techniques the accuracy of the proposed boundary element methodology is demonstrated by means of representative numerical examples

analyticity of entropy rate of hidden markov chains with continuous alphabet we first prove that under certain mild assumptions the entropy rate of a hidden markov chain observed when passing a finite state stationary markov chain through a discrete time continuous output channel is analytic with respect to the input markov chain parameters we then further prove under strengthened assumptions on the channel that the entropy rate is jointly analytic as a function of both the input markov chain parameters and the channel parameters in particular the main theorems establish the analyticity of the entropy rate for two representative channels 1 cauchy and 2 gaussian the analyticity results obtained are expected to be helpful in computation estimation of entropy rate of hidden markov chains and capacity of finite state channels with continuous output alphabet

an efficient and highly accurate solver for multi body acoustic scattering problems involving rotationally symmetric scatterers a numerical method for solving the equations modeling acoustic scattering in three dimensions is presented the method is capable of handling several dozen scatterers each of which is several wave lengths long on a personal work station even for geometries involving cavities solutions accurate to seven digits or better were obtained the method relies on a boundary integral equation formulation of the scattering problem discretized using a high order accurate nystrom method a hybrid iterative direct solver is used in which a local scattering matrix for each body is computed and then gmres accelerated by the fast multipole method is used to handle reflections between the scatterers the main limitation of the method described is that it currently applies only to scattering bodies that are rotationally symmetric

bounds on the information rate of intertransition time restricted binary signaling over an awgn channel upper and lower bounds on the capacity of a continuous time additive white gaussian noise awgn channel with bilevel spl plusmn spl radic p input signals subjected to a minimum inter transition time t sub min constraint are derived the channel model and input constraints reflect basic features of certain magnetic recording systems the upper bounds are based on duncan s relation between the average mutual information in an awgn regime and the mean square error mse of an optimal causal estimator evaluation or upper bounding the mse of suboptimal causal estimators yields the desired upper bounds the lower bound is found by invoking the extended mrs gerber s lemma and asymptotic properties of the entropy of max entropic bipolar d k codes asymptotic results indicate that at low snr pt sub min n sub 0 with n sub 0 designating the noise one sided power spectral density the capacity tends to p n sub 0 nats per second nats s i e it equals the capacity in the simplest average power limited case at high snr the capacity in the simplest average power limited case at high snr the capacity behaves asymptotically as t sub min sup 1 ln snr ln snr nats s demonstrating the degradation relatively to t sub avg sup 1 lnsnr which is the asymptotic known behavior of the capacity with a bilevel average intertransition time t sub avg restricted channel input additional lower bounds are obtained by considering specific signaling formats such as pulsewidth modulation the effect of mild channel filtering on the lower bounds on capacity is also addressed and novel techniques to lower bound the capacity in this case are introduced

constraint gain in digital storage systems where the input to the noisy channel is required to satisfy a modulation constraint the constrained code and error control code ecc are typically designed and decoded independently the achievable rate for this situation is evaluated as the rate of average intersection of the constraint and the ecc the gap from the capacity of the noisy constrained channel is called the constraint gain which represents the potential improvement in combining the design and decoding of the constrained code and the ecc the constraint gain is computed for various constraints over the binary input additive white gaussian noise awgn channel biawgnc as well as over intersymbol interference isi channels finally it is shown that an infinite cascade of reverse concatenation with independent decoding of constraint and ecc has a capacity equal to the rate of average intersection

a generalized upper bound and a multilevel construction for distance preserving mappings a new general upper bound is derived on the sum of the hamming distances between sequences when mapping from one set of sequences to another it is shown that a similar upper bound for mappings from binary sequences to permutation sequences is a special case of this upper bound and this is used to evaluate known mappings also new distance preserving mappings dpms from binary sequences to permutation sequences are presented based on a multilevel construction in addition to explicit distance conserving mappings distance increasing and distance reducing mappings are also presented several of the new dpms attain the upper bound

a boundary integral approach for acoustic radiation of axisymmetric bodies with arbitrary boundary conditions valid for all wave numbers a boundary integral method for solving the exterior acoustic radiation problem of axisymmetric bodies with arbitrary boundary conditions is developed the new formulation derives from the method proposed by burton and miller proc r soc london ser a 323 201 210 1971 which uses a linear combination of the helmholtz integral equation and its normal derivative to ensure the uniqueness of the numerical solution at all frequencies it is shown that the use of tangential operators enables one to easily compute the hypersingular integral without much extra effort by taking advantage of the properties of axisymmetric geometry and using the expansion of the boundary conditions and the surface distribution functions in fourier series with respect to the angle of revolution the surface integral is reduced to a line integral along the generator of the body and fourier integrals of the green s function and its derivatives over the circumferential angle the fourier integrals with singular kernels are eval

new bounds and constructions for granular media coding improved lower and upper bounds on the size and the rate of grain correcting codes are presented the lower bound is gilbert varshamov like combined with a construction by gabrys et al and it improves on the previously best known lower bounds on the asymptotic rate of lceil tau n rceil grain correcting codes of length n on the interval 0 0 0668 one of the two newly presented upper bounds improves on the best known upper bounds on the asymptotic rate of lceil tau n rceil grain correcting codes of length n on the interval tau in 0 1 8 and meets the lower bound of 1 2 for tau geq 1 8 moreover in a nonasymptotic regime both upper bounds improve on the previously best known results on the largest size of t grain correcting codes of length n for certain values of n and t constructions of 1 grain correcting codes based on a partitioning technique are presented for lengths up to 18 finally a lower bound of 1 2 log 2 n on the minimum redundancy of infty grain detecting codes of length n is presented

elastic scatterer interaction via generalized born series and far field approximations methods for solving elastic wave scattering problems in three dimensions 3d with multiple inhomogeneities are discussed a problem of homogeneous isotropic elastic defects in an otherwise homogeneous isotropic elastic full space is formulated as a boundary integral equation this equation is solved by discretizing the surface of each scatterer in a fashion known as the boundary element method the resulting matrix equation may be solved in a fully implicit manner but an implicit iterative method is more efficient with this hybrid method a portion of the nonsingular integral operator is expanded in a neumann series terms in this series correspond physically to nth order born approximations of the scatterers interaction the relative advantage of this hybrid scheme depends on the number of iterations required except for closely situated strong scatterers terms beyond the first few orders are not significant and thus the method can be quite advantageous when the separation is large another appro

state splitting for variable length graphs corresp the state splitting algorithm of adler coppersmith and hassner for graphs with edges of fixed length is extended to graphs with edges of variable lengths this has the potential to improve modulation code construction techniques although the ideas of state splitting come from dynamical systems completely graph theoretic terms are used

a boundary integral formulation for the prediction of acoustic scattering from periodic structures the scattering of sound by reflecting surfaces is an important feature in room acoustics the boundary element method has been shown in the past to be an accurate method to calculate the scattering pattern of complex surfaces however this numerical method is expensive to use on large surfaces where a large number of elements is required this paper proposes a method of reducing the number of boundary elements required to model large but periodic structures the method is based on a consideration of the relationship between the field variables at two points exactly one period apart the problem is reduced to the modeling of just one period of the structure in cases of plane wave incidence the prediction using this method agrees very well with the prediction obtained by modeling the complete structure with the point source in the near field of the surface the incidence field is no longer periodic and the assumption of a constant periodic factor does not hold in this case it is shown that the metho

reliable communications across parallel asynchronous channels with arbitrary skews transmissions across asynchronous communication channels are subject to delay injection attacks which can cause an arbitrary number of skews that is such attacks can cause an arbitrary number of transmitted signals to arrive after the first signal of the next transmission has arrived the common assumption that despite the delays all signals from the i th transmission arrive at the decoder before any signal from the i 2 text nd transmission arrives is called a no switch assumption this paper presents a self synchronizing zero latency zero error coding scheme that requires no acknowledge and can decode transmissions distorted by an arbitrary number of skews that obey this no switch assumption the rate associated with the coding scheme provides a lower bound of 0 6942 for the zero error capacity of such a channel it is further shown that zero error channel capacity of the channel is upper bounded by 0 7248 finally this paper presents bounds on the zero error capacity of a channel for which the number of transmissions that can mix with one another is large

variable length state splitting with applications to average runlength constrained arc codes a new class of constrained systems average runlength constraints arcs is defined by requiring that the sum of n consecutive run lengths be bounded above by a linear function of n in particular the running average runlength of every sequence in the system is bounded above by a constant a general result is given on the capacity of arc systems the state splitting algorithm is then improved for variable length graphs this is then applied to obtain high fixed rate codes from the free binary source to arc systems as an example a rate 1 2 d k

simulation based computation of information rates for channels with memory the information rate of finite state source channel models can be accurately estimated by sampling both a long channel input sequence and the corresponding channel output sequence followed by a forward sum product recursion on the joint source channel trellis this method is extended to compute upper and lower bounds on the information rate of very general channels with memory by means of finite state approximations further upper and lower bounds can be computed by reduced state methods

on the power spectral density of constrained sequences this paper derives a simple closed form expression for computing the power spectral density psd of constrained sequences whose constraints are characterized by a function of an ergodic markov process specified in terms of a mealy machine a suitable matrix description of the stochastic behavior of the constrained sequence is used to express its autocorrelation sequence in a compact matrix form that simplifies the calculation of the psd examples of the application of this technique in cases of practical interest are provided including differentially encoded binary sequences source driven binary huffman codes maximum entropy d k codes and convolutional or block encoded sequences a unified treatment to several widely used constrained sequences is provided

a binary analog to the entropy power inequality let x sub n y sub n be independent stationary binary random sequences with entropy h x h y respectively let h zeta zeta log zeta 1 zeta log 1 zeta 0 or sigma x sigma y where sigma z h sup 1 h z and alpha beta alpha 1 beta beta 1 alpha when y sub n are independent identically distributed this reduces to mrs gerber s lemma from a d wyner and j ziv 1973

on the capacity of a direct detection photon channel with intertransition constrained binary input the classical directed detection photon channel is modeled by an output nu sub t observed signal describing the photon arrival poisson count process with intensity rate lambda sub t lambda sub 0 where lambda sub t photons s is the channel input information carrying intensity and lambda sub 0 photons s is the dark current intensity upper and lower bounds on the capacity of this channel are presented for two level binary inputs taking on the extreme value lambda sub t in 0 a where a denotes the peak power satisfying an average power constraint e lambda sub t

subset source coding this paper studies the fundamental limits of storage for structured data where statistics and structure are both critical to the application accordingly a framework is proposed for optimal lossless and lossy compression of subsets of the possible realizations of a discrete memoryless source dms for the lossless subset compression problem it turns out that the optimal source code may not index the conventional source typical sequences but rather index certain subset typical sequences consistent with the subset of interest building upon an achievability and a strong converse an analytic expression is given based on the shannon entropy relative entropy and subset entropy which identifies such subset typical sequences for a broad class of subsets of a dms intuitively subset typical sequences belong to those typical sets which highly intersect the subset of interest but are still closest to the source distribution in the sense of relative entropy for the lossy subset compression problem an upper bound is derived on the subset rate distortion function in terms of the subset mutual information optimized over the set of conditional distributions that satisfy the expected distortion constraint with respect to the subset typical distribution and over a set of certain auxiliary subsets by proving a strong converse result this upper bound is shown to be tight for a class of symmetric subsets as shown in our numerical examples more often than not one achieves a gain in the fundamental limits in that the optimal compression rate for the subset in both the lossless and lossy settings can be strictly smaller than the source entropy and the source rate distortion function respectively although exceptions are also possible

capacity achieving code constructions for two classes of d k constraints this correspondence presents two variable rate encoding algorithms that achieve capacity for the d k constraint when k 2d 1 or when k d 1 is not prime the first algorithm symbol sliding is a generalized version of the bit flipping algorithm introduced by aviran in addition to achieving capacity for d 2d 1 constraints it comes close to capacity in other cases the second algorithm is based on interleaving and is a generalized version of the bit stuffing algorithm introduced by bender and wolf this method uses fewer than k d biased bit streams to achieve capacity for d k constraints with k d 1 not prime in particular the encoder for d d 2 sup m 1 constraints 2 spl les m spl infin requires only m biased bit streams

timing metrics for constrained codes the effect of data constraints on synchronization is quantified by the use of three simple timing metrics that respectively measure the ensemble average the worst and the best timing qualities attainable with a given binary pulse amplitude modulation pam waveform these timing metrics are computed with the help of a graph which represents the constrained pam system the timing metrics of the 0 k constraint are studied in detail for selected pam pulses

distance preserving and distance increasing mappings from ternary vectors to permutations permutation arrays have found applications in powerline communication one construction method for permutation arrays is to map good codes to permutations using a distance preserving mappings dpm dpms are mappings from the set of all q ary vectors of a fixed length to the set of permutations of some fixed length the same or longer such that every two distinct vectors are mapped to permutations with the same or larger hamming distance than that of the vectors a dpm is called distance increasing dim if the distances are strictly increased except when the two vectors are equal in this correspondence we propose constructions of dpms and dims from ternary vectors the constructed dpms and dims improve many lower bounds on the maximal size of permutation arrays

spectral analysis of maximum entropy multitrack modulation codes the problem of calculating the power spectral density of a constrained maxentropic vector sequence a sup n a sup n a sub i sup n sub 0 spl les i spl les n 1 is considered the constraints of the constituent sequences a sub i sup n are defined by the sofic systems s sub i presented by the directed graphs g sub i 0 spl les i spl les n 1 but the vector sequence itself is constrained additionally and given by a function spl phi of constituent graphs g spl phi g sub 0 spl middot spl middot spl middot g sub n 1 this class of vector constraints is met in parallel multitrack recording the general case of a simultaneous recording on n tracks is considered assuming that the common vector constraint is track invariant

optimal block codes for m ary runlength constrained channels in this work we consider the analysis and design of optimal block decodable m ary runlength limited rll codes we present two general construction methods one based on permutation codes due to datta and mclaughlin 1999 and the other a nonbinary generalization of the binary enumeration methods of patrovics and immink 1996 and gu and fuja 1994 the construction based on permutation codes is simple and asymptotically in block length optimal while the other construction is optimal in the sense that the resulting codes have the highest rate among all block decodable codes for any block length in the process we shall also extend a result due to zehavi and wolf 1988 on the capacity of binary d k constraints to m ary channels finally we present examples of template codes remarkably low complexity m d k block codes which achieve the optimal rate without the use of enumeration

multiple scattering and modified green s functions abstract exterior boundary value problems for the helmholtz equation can be reduced to boundary integral equations it is known that the simplest of these fail to be uniquely solvable at certain irregular frequencies for a single smooth scatterer it is also known that irregular frequencies can be eliminated by using a modified fundamental solution one that has additional singularities inside the scatterer this approach is extended to treat the three dimensional exterior neumann problem for any finite number of disjoint smooth scatterers using a fundamental solution that has additional singularities inside every scatterer

deterministic coding capacity of networks in the low power regime the deterministic coding capacity of a network is the capacity of a network when nodes are restricted to transmitting reliable information that is asymptotically deterministic functions of the source messages this is a generalization of network coding to wireless networks the main contribution of this paper is to develop new outer bounds on the deterministic coding capacity in the low power regime mathrm snr to 0 this is accomplished by developing a technique for finding the limits of single letter bounds for mathrm snr to 0 even when these cannot be evaluated for finite snr it is shown that these outer bounds are tight in a number of cases including the butterfly network of ahlswede et al in a wireless setting

bounds on the zero error capacity of the input constrained bit shift channel new lower and upper bounds on a maximal achievable rate fur runlength limited codes capable of correcting any combination of bit shift errors i e a zero error capacity of the bit shift channel are presented the lower bound is a generalization of the bound obtained by shamai and zehavi 1991 it is shown that in certain cases the upper and the lower bounds asymptotically coincide

the feedback capacity of the binary erasure channel with a no consecutive ones input constraint the input constrained erasure channel with feedback is considered where the binary input sequence contains no consecutive ones i e it satisfies the 1 infty rll constraint we derive the capacity for this setting which can be expressed as c epsilon max 0 leq p leq 0 5 frac 1 epsilon h b p 1 1 epsilon p where epsilon is the erasure probability and h b cdot is the binary entropy function moreover we prove that a priori knowledge of the erasure at the encoder does not increase the feedback capacity the feedback capacity was calculated using an equivalent dynamic programming dp formulation with an optimal average reward that is equal to the capacity furthermore we obtained an optimal encoding procedure from the solution of the dp leading to a capacity achieving zero error coding scheme for our setting dp is thus shown to be a tool not only for solving optimization problems such as capacity calculation but also for constructing optimal coding schemes the derived capacity expression also serves as the only non trivial upper bound known on the capacity of the input constrained erasure channel without feedback a problem that is still open

achievable performance over the correlated rician channel the correlated rician channel is a useful model for a slowly fading channel in which the complex fading process is composed of two quadrature gaussian processes with a given autocorrelation function for slow fading the correlation between adjacent symbols is relatively high the authors investigate the achievable error probabilities over the channel employing coherent detection and ideal side information on the realization of the fading processes at the receiver an underlying decoding delay constraint which precludes the use of ideal interleaving is assumed coded bpsk performance is addressed both with and without the piecewise constant approximation according to which the fading value remains constant during the symbol duration for the latter case that is no piecewise constant approximation the analysis relies on the fredholm determinant associated with the fading process autocorrelation function the authors focus on the exponentially correlated channel the worst case pairs of codewords are identified the exponential behavior of the error probability with random coding and i i d gaussian inputs is analyzed and the behavior of the cut off rate and capacity is addressed the results enhance the insight to the effect of the basic parameters governing the performance and these are examined in view of previous works and compared to relevant performance results for the block fading channel model

capacity and error exponent for the direct detection photon channel ii for pt i see ibid vol 34 no 6 p 1449 61 1980 the discussion of the capacity and error exponent of the direct detection optical channel is continued the channel input in a t second interval is a waveform satisfying certain peak and average power constraints for the optical signals the channel output is a poisson process with an intensity parameter that accounts for the dark current component an upper bound is obtained on the error exponent which coincides with the lower bound thus this channel is one for which the error exponent can be known exactly

markov processes asymptotically achieve the capacity of finite state intersymbol interference channels recent progress in capacity evaluation has made it possible to compute a sequence of lower bounds on the capacity of a finite state intersymbol interference isi channel by finding a sequence of optimized markov input processes with increasing order for which the state of the process is the previous input symbols in this correspondence we prove that as the order goes to infinity the sequence of optimized markov sources asymptotically achieves the capacity of the channel the conclusion is extended to two dimensional finite state isi channels the binary symmetric channel bsc with constrained inputs and general indecomposable finite state channels with a mild constraint

a multiple insertion deletion correcting code for run length limited sequences a code construction is proposed to add a multiple insertion deletion error correcting capability to a run length limited sequence the codewords of this code are themselves run length limited the insertion deletion correcting capability is achieved by requiring several weighted sums of run lengths in the codewords to satisfy certain congruences modulo primes the construction is similar to the number theoretic code proposed by dolecek and anantharam which can correct multiple repetition errors or equivalently multiple insertions of zeros it is shown that if the codewords in this code are run length limited then the code is capable of correcting both insertions and deletions of zeros and ones an algorithm is proposed for decoding over a multiple insertion deletion channel following the work of dolecek and anantharam a systematic encoding method is also proposed for the codes furthermore it is shown that the proposed construction has a higher rate asymptotically than the helberg code which is unconstrained in terms of run lengths even though our construction has the additional run length constraints the need for run length limited codes that can correct insertion deletion errors is motivated by bit patterned media for magnetic recording

on the capacity of binary and gaussian channels with run length limited inputs bounds on the capacity of binary symmetric channels and additive gaussian channels with run length limited two level binary bipolar inputs are presented and their tightness is demonstrated for some cases stationary input sequences which do not degrade capacity are considered when deriving the bounds lower bounds on the magnetic recording density for a simple continuous time recording model incorporating a minimal intertransition constraint are evaluated for soft and hard decisions a superiority of about 1 5 db in signal to noise ratio is observed for the soft decision scheme

on runlength codes several results on binary d k codes are given first a novel derivation for the capacity of these codes based on information theoretic principles is given based on this result the spectrum of a d k code is computed finally the problem of computing the capacity of the binary symmetric channel under the condition that the input sequences satisfy the d k constraint is considered lower bounds on the capacity of such a channel are derived

lower bounds on achievable rates for limited bitshift correcting codes limited codes runlength limited charge constrained and so on capable of correcting shifts of their symbols are considered the error correction ability is characterized by the minimal bitshift distance d sub bs of a code for a given spl delta d sub bs n where n is the code length the achievable code rate r sub spl alpha is lower bounded we prove the existence of codes of rate r spl ges r sub spl alpha

a novel technique in boundary integral equations for analyzing acoustic radiation from axisymmetric bodies a novel technique is suggested to avoid singular integrals of boundary integral equations bie for exterior sound radiation problems the technique reproduction of diagonal terms rdt utilizes special solutions of some monopole sources which give the distribution of theoretical surface pressure and velocity to reproduce diagonal terms in the bie matrices it is proposed to employ three monopole sources in reproduction of diagonal terms in both pressure and velocity matrices although the interior points are applied to generate monopole solutions the concept is basically different from that of general interior helmholtz equations so the present technique is different from those traditional methods to improve bie method through added interior helmholtz equations several examples are presented to demonstrate the effectiveness of the proposed technique for closed axisymmetric surfaces numerical results show that the technique of rdt can improve the accuracy of the solution up to 10 times compared to the conventional techniques such as shf chief shf

concavity of the mutual information rate for input restricted memoryless channels at high snr we consider a memoryless channel with an input markov process supported on a mixing finite type constraint we continue the development of asymptotics for the entropy rate of the output hidden markov chain and deduce that at high signal to noise ratio the mutual information rate of such a channel is concave with respect to almost all input markov chains of a given order

asymptotics of input constrained erasure channel capacity in this paper we examine an input constrained erasure channel and we characterize the asymptotics of its capacity when the erasure rate is low more specifically for a general memoryless erasure channel with its input supported on an irreducible finite type constraint we derive partial asymptotics of its capacity using some series expansion type formula of its mutual information rate and for a binary erasure channel with its first order markovian input supported on the 1 infty rll constraint based on the concavity of its mutual information rate with respect to some parameterization of the input we numerically evaluate its first order markov capacity and further derive its full asymptotics the asymptotics obtained in this paper when compared with the recently derived feedback capacity for a binary erasure channel with the same input constraint enable us to draw the conclusion that feedback may increase the capacity of an input constrained channel even if the channel is memoryless

acoustic scattering by a hard or soft body across a wide frequency range by the helmholtz integral equation method in this paper the acoustic scattering by an obstacle across a wide frequency range of sound waves is investigated on the basis of the helmholtz integral formulation to overcome the nonuniqueness difficulties the methods proposed by burton npl report nac 30 jan 1973 and by burton and miller proc r soc london ser a 323 201 210 1971 are adopted for the dirichlet and neumann problems respectively the aim of this paper is twofold the first is to bring together completely regular formulations of the helmholtz integral equation and its normal derivative the second is to extend these formulations to treat the higher frequency problems the weakly singular integrals are regularized by subtracting out one term and adding it back depending on the problem concerned the additional integral can finally be expressed in an explicit form or results in solving a surface source distribution of the equipotential body the hypersingular kernels are regularized by the method of using some properties of the associated laplace equation originally proposed by chien et al j acoust soc am 88 918 937 1990 the completely regularized integral equations are amenable to computation by direct use of the standard quadrature methods to study the acoustic scattering due to higher frequency waves filon s quadrature method proc r soc edinburgh 49 38 47 1928 is extended to treat the rapidly oscillatory integrands numerical examples consist of acoustic scattering from a hard or soft sphere of radius a across a wide spectrum of wave numbers ka 20 comparisons of the numerical results with the exact solutions demonstrate the validity and efficiency of the implementation

constant weight and constant charge binary run length limited codes constant weight and constant charge binary sequences with constrained run length of zeros are introduced the weight and charge distribution for these sequences are found next recurrent and direct formulas for calculating the number of these sequences are obtained by considering these numbers of constant weight and constant charge run length limited rll sequences as coefficients of convergent power series generating functions are derived the fact that generating function for enumerating constant charge rll sequences does not have a closed form is proved subsequently implementation of encoding and decoding procedures using cover s enumerative scheme is shown based on the obtained results some examples such as enumeration of running digital sum rds constrained rll sequences or peak shifts control capability are also provided

a boundary integral equation method for two dimensional acoustic scattering problems this work formulates the singularity free integral equations to study 2 d acoustic scattering problems to avert the nonuniqueness difficulties burton s and burton and miller s methods are employed to solve the dirichlet and neumann problems respectively the surface helmholtz integral equations and their normal derivative equations in bounded form are derived the weakly singular integrals are desingularized by subtracting a term from the integrand and adding it back with an exact value depending on the relevant problem the additional integral can finally be either expressed in an explicit form or transformed to form a surface source distribution of the related equipotential body the hypersingular kernel is desingularized further using some properties of an interior laplace problem the new formulations are advantageous in that they can be computed by directly using standard quadrature formulas also discussed is the contour a unique feature of 2 d problems instead of dividing the boundary surface into several small elements a parametric representation of a 2 d boundary curve is further proposed to facilitate a global numerical implementation calculations consist of acoustic scattering by a hard and a soft circular cylinder respectively comparing the numerical results with the exact solutions demonstrates the proposed method s effectiveness

the capacity of binary channels that use linear codes and decoders this paper analyzes the performance of concatenated coding systems operating over the binary symmetric channel bsc by examining the loss of capacity resulting from each of the processing steps the techniques described in this paper allow the separate evaluation of codes and decoders and thus the identification of where loss of capacity occurs they are moreover very useful for the overall design of a communications system e g for evaluating the benefits of inner decoders that produce side information the first two sections of this paper provide a general technique based on the coset weight distribution of a binary linear code for calculating the composite capacity of the code and a bsc in isolation the later sections examine the composite capacities of binary linear codes the bsc and various decoders the composite capacities of the 8 4 extended hamming 24 12 extended golay and 48 24 quadratic residue codes appear as examples throughout the paper the calculations in these examples show that in a concatenated coding system having an inner decoder provide more information than the maximum likelihood ml estimate to an outer decoder is not a computationally efficient technique unless generalized minimum distance decoding of an outer code is extremely easy specifically for the 8 4 extended hamming and 24 12 extended golay inner codes the gains from using any inner decoder providing side information instead of a strictly ml inner decoder are shown to be no greater than 0 77 and 0 34 db respectively for a bsc crossover probability of 0 1 or less however if computationally efficient generalized minimum distance decoders for powerful outer codes e g reed solomon codes become available they will allow the use of simple inner codes since both simple and complex inner codes have very similar capacity losses

noisy constrained capacity for bsc channels we study the classical problem of noisy constrained capacity in the case of the binary symmetric channel bsc namely the capacity of a bsc whose input is a sequence from a constrained set as stated by fan while calculation of the noise free capacity of constrained sequences is well known the computation of the capacity of a constraint in the presence of noise has been an unsolved problem in the half century since shannon s landmark paper we first express the constrained capacity of a binary symmetric channel with d k constrained input as a limit of the top lyapunov exponents of certain matrix random processes then we compute asymptotic approximations of the noisy constrained capacity for cases where the noise parameter e is small in particular we show that when k 2d the error term excess of capacity beyond the noise free capacity is o e whereas it is o eloge when k 2d in both cases we compute the coefficient of the error term in the course of establishing these findings we also extend our previous results on the entropy of a hidden markov process to higher order finite memory processes these conclusions are proved by a combination of analytic and combinatorial methods

shannon capacity of m ary redundant multitrack runlength limited codes we consider multiamplitude multitrack runlength limited d k constrained channels with and without clock redundancy we calculate the shannon capacities of these channels and present some simple 100 efficient codes to compute capacity a constraint graph equivalent to the usual runlength limited constraint graph is used the introduced graph model has the vertex labeling independent of number of tracks to be written on in parallel which provides computational savings when the number of tracks is large we show that increasing the number of tracks written on in parallel provides significant increase of per track capacity for the more restrictive clocking constraint case i e when k d but it does not have much influence on the channel capacity when k spl ges d

on the capacity of channels with timing synchronization errors we consider a new formulation of a class of synchronization error channels and derive analytical bounds and numerical estimates for the capacity of these channels for the binary channel with only deletions we obtain an expression for the symmetric information rate in terms of subsequence weights which reduces to a tight lower bound for small deletion probabilities we are also able to exactly characterize the markov 1 rate for the binary channel with only replications for a channel that introduces deletions as well as replications of input symbols we design approximating channels that parameterize the state space and show that the information rates of these approximate channels approach that of the deletion replication channel as the state space grows for the case of the channel where deletions and replications occur with the same probabilities a stronger result in the convergence of mutual information rates is shown the numerous advantages this new formulation presents are explored

generating functions and lower bounds on rates for limited error correcting codes runlength limited rll and digital sum limited dsl codes are considered for these codes the finite and asymptotic lower bounds on achievable rates for the given minimum hamming distance are derived using generating functions and trellis diagram techniques the authors prove the existence of rll and dsl codes of rate r and minimum distance d delta n such that r or 2 log lambda sub 1 0 min log lambda sub 1 z delta log z 0

hamming distance preserving mappings and trellis codes with constrained binary symbols the transformation of a linear convolutional code into a run length constrained or balanced trellis code with the same or larger free distance is investigated the transformation involves a hamming distance preserving mapping of the set of unconstrained binary symbols of the convolutional code onto a set of suitably constrained symbols simple tests to determine if these mappings can exist and a tree search algorithm for finding such mappings are presented

zero error capacity of a class of timing channels we analyze the problem of zero error communica tion through certain timing channels that can be interpreted as discrete time queues with bounded waiting times these timing channels are partly motivated by settings in which communica tion is done with rather unconventional physical carriers such as particles molecules items etc the channel model includes the following assumptions 1 at most n particles are sent in each time slot 2 every particle is delayed in the channel for a number of slots chosen randomly from the setf0 1 kg and 3 the particles are indistinguishable and hence the information is conveyed via the number of particles in each slot only it is shown that the zero error capacity of this channel is logr where r is the unique positive real root of the polynomialx k 1 x k n it is interesting to note that in the particular case n 1 k 1 the capacity is equal to log where 1 p 5 2 is the golden ratio capacity achieving codes are explicitly constructed index terms error correcting code zero error capacity zero error code timing channel timing capacity discrete time queue fibonacci sequence recurrence relation

a fast wave superposition spectral method with complex radius vector combined with two dimensional fast fourier transform algorithm for acoustic radiation of axisymmetric bodies abstract based on the two dimensional fast fourier transform 2d fft algorithm a wave superposition spectral method with complex radius vector has been proposed to efficiently analyze the acoustic radiation from an axisymmetric body first the complex fourier series are used along both circumferential and meridian directions to expand the integral kernel function and unknown source strength density distributed function then by means of the rectangular integral formula the radiation sound pressure is described in the form of two dimensional discrete fourier transform and generalized through 2d fft algorithm finally several numerical examples are performed to verify the accuracy and efficiency of the present method comparing with the other existing analysis ways the present method has three different characteristics 1 there is no singular integral in the numerical computation 2 the unique solution can be given for all eigen wavenumbers owing to the application of the virtual boundary technology with complex radius vector and 3 the computational efficiency is improved remarkably because all fourier terms are calculated simultaneously through 2d fft algorithm

an analytical fundamental solution of the transient scalar wave equation for axisymmetric systems in the present paper a new time domain fundamental solution for axisymmetric scalar wave propagation problems is developed the result is an analytical expression which can be used in boundary element formulations in a more accurate way than the numerical integration procedures known so far the circumferential integration of the 3d fundamental solution necessary to take into account the axisymmetry is shown and two examples are presented in order to demonstrate the accuracy and the applicability of the new formulation

bounds on the capacity of the bit shift magnetic recording channel a simple statistical channel model is suggested to account for single position bit shifts that have been identified as one of the major impairments in magnetic recording the authors investigate bounds on the capacity of this channel where the channel inputs are the d k codes commonly used in magnetic recordings for d or 2 this channel is conveniently described in terms of phrase lengths where a bit shift causes a phrase either to shrink or to expand the inherent correlation present in consecutive shift affected phrases introduces memory into the channel model sequences of nondecreasing lower bounds and nonincreasing upper bounds on the capacity are evaluated and investigated for a variety of parameters lower bounds on the zero error capacity are also studied the channel model is extended to a concatenated scheme of a bit shift channel connected in tandem with the binary symmetric channel thus capturing both major error generating mechanisms the bit shifts as well as randomly generated errors lower and upper bounds on the capacity of this concatenated channel model with d k input sequences are derived and discussed

binary transmission codes with higher order spectral zeros at zero frequency corresp a method is presented for designing binary channel codes in such a way that both the power spectral density function and its low order derivatives vanish at zero frequency the performance of the new codes is compared with that of channel codes designed with a constraint on the unbalance of the number of transmitted positive and negative pulses some remarks are made on the error correcting capabilities of these codes

capacity analysis for integrate and fire neurons with descending action potential thresholds understanding how a biological neuron works has been a major goal in neuroscience under the poisson excitation assumption results from earlier study by suksompong and berger on the timing jitter in the leaky integrate and fire lif model of neurons are used to determine families of neural thresholding functions that are appropriate in certain interesting senses next the neuron is treated as a communication channel for which information theoretic quantities can be calculated in particular the optimal distribution of the poisson excitation intensity is numerically evaluated along with the corresponding capacity using the blahut arimoto algorithm simple formulas which approximate the optimal intensity distribution are given furthermore the jimbo kunisawa algorithm is used to explore energy efficient operations for neuron finally a rate matching argument leads to a unique operating condition which turns out to agree with experimentally observed rate

perfect d k codes capable of correcting single peak shifts codes for the multibit peak shift recording channel called d k codes of reduced length n are considered arbitrary d k and perfect d k codes capable of correcting single peak shifts of given size t are defined for the construction of perfect codes a general combinatorial method connected with finding good weight sequences in abelian groups is used and the concept of perfect t shift n designs is introduced explicit constructions of such designs for t 1 t 2 and t p 1 2 are given where p is a prime this construction is universal in that it does not depend on the d k constraints it also allows automatic correction of those peak shifts that violate d k constraints the construction is extended to d k codes of fixed binary length and allows the beginning of the next codeword to be determined the question whether the designed codes can be represented as systematic codes with minimal redundancy is considered as well

an enumerative method for runlength limited codes permutation codes permutation codes introduced by slepian 1965 were shown to perform well on an additive white gaussian noise awgn channel unfortunately these codes required large lookup tables making them quite complex to implement even though the maximum likelihood decoder is very simple in this correspondence we present an enumeration scheme which encodes and decodes permutation codes with low complexity we concentrate on the use of permutation codes for constructing high rate codes that satisfy runlength limited constraints wolf 1990 showed that permutation codes can be used for runlength constraints and that they have rate that asymptotically achieves the capacity of a noiseless runlength limited constrained channel wolf however gave no efficient encoders decoder our code construction is enumerative but unlike other enumerative codes has storage requirements that are a function of the runlength parameters d and k instead of the block length n in addition these codes have error detection and correction capabilities finally we use this approach to construct 0 g i codes whereby all odd numbered occurrences of double adjacent errors are detected as an example a 99 2 efficient rate 498 528 0 6 3 code is presented

on channel capacity per unit cost memoryless communication channels with arbitrary alphabets where each input symbol is assigned a cost are considered the maximum number of bits that can be transmitted reliably through the channel per unit cost is studied it is shown that if the input alphabet contains a zero cost symbol then the capacity per unit cost admits a simple expression as the maximum normalized divergence between two conditional output distributions the direct part of this coding theorem admits a constructive proof via stein s lemma on the asymptotic error probability of binary hypothesis tests single user multiple access and interference channels are studied

a randomized algorithm for the capacity of finite state channels inspired by ideas from the field of stochastic approximation we propose a randomized algorithm to compute the capacity of a finite state channel with a markovian input when the mutual information rate of the channel is concave with respect to the chosen parameterization the proposed algorithm proves to be convergent to the capacity of the channel almost surely with the derived convergence rate we also discuss the convergence behavior of the algorithm without the concavity assumption

a note on the shannon capacity of run length limited codes corresp it is proven that 100 percent efficient fixed rate codes for run length limited rll d k and rll charge constrained d k c channels are possible in only two eases namely d k c 0 1 1 and 1 3 3 specifically the binary shannon capacity of rll d k constrained systems is shown to be irrational for all values of d k 0 leq d for rll charge constrained systems with parameters d k c the binary capacity is irrational for all values of d k c 0 leq d except 0 1 1 and 1 3 3 which both have binary capacity 1 2

a special integral equation formulation for acoustic radiation and scattering for axisymmetric bodies and boundary conditions this paper presents a simplified model of the helmholtz integral equation for bodies with axisymmetric shape and boundary conditions by taking advantage of a body s axisymmetric properties the surface integral is reduced to a line integral along the generator of the body and an integral over the angle of revolution the integration over the angle is performed partly analytically in terms of elliptic integrals and partly numerically using a gaussian quadrature formula the analytical formulation leading to elliptic integrals deals directly with the singularities in the green s function and its normal derivative examples are shown for scattering from a single sphere and two spheres and radiation from a finite cylinder the results are compared with analytical approximate and other accepted solutions

improved gilbert varshamov bound for constrained systems nonconstructive existence results are obtained for block error correcting codes whose codewords lie in a given constrained system each such system is defined as a set of words obtained by reading the labels of a finite directed labeled graph for a prescribed constrained system and relative minimum distance delta the new lower bounds on the rate of such codes improve on those derived recently by v d kolesnik and v y krachkovsky 1991 the better bounds are achieved by considering a special subclass of sequences in the constrained system namely those having certain empirical statistics determined by delta

the power spectrum of run length limited codes a novel method is developed for computing formulas for power spectra associated with run length limited rll codes explicit use is made of a compact description of the run length process associated with the rll code this association simplifies the general derivation of the power spectrum the calculation of the spectra of several rll codes popular in data storage applications is presented some of the closed form expressions for the spectra of these widely used codes are new

distance spectrum formulas on the largest minimum distance of block codes a general formula for the asymptotic largest minimum distance in block length of deterministic block codes under generalized distance functions not necessarily additive symmetric and bounded is presented as revealed in the formula the largest minimum distance can be fully determined by the ultimate statistical characteristics of the normalized distance function evaluated under a properly chosen random code generating distribution interestingly the new formula has an analogous form to the general information spectrum expressions of the channel capacity and the optimistic channel capacity respectively derived by verdu and han 1994 and chen and alajaji 1998 1999 as a result a minor class of distance functions for which the largest minimum distance can be derived is characterized a general varshamov gilbert lower bound is next addressed some discussions on the tightness of the general varshamov gilbert bound are also provided finally lower bounds on the largest minimum distances for several specific block coding schemes are rederived in terms of the new formulas followed by comparisons with the known results devoted to the same codes

on the distribution of runs of ones in binary strings in this paper we derive the number of binary strings which contain for a given i k exactly i k runs of 1 s of length k in all possible binary strings of length n email protected email protected n such a knowledge about the distribution pattern of runs of 1 s in binary strings is useful in many engineering applications for example data compression bus encoding techniques to reduce crosstalk in vlsi chip design computer arithmetic using redundant binary number system and design of energy efficient communication schemes in wireless sensor networks by transformation of runs of 1 s into compressed information patterns among others we present here a generating function based approach to derive a solution to this counting problem our experimental results demonstrate that for most commonly used file formats the observed distributions of exactly i k runs of length k email protected email protected n closely follow the theoretically derived distributions for a given n for n 8 we find that the experimentally obtained values for most file formats agree within 5 of the theoretically obtained values for all i k runs of length k email protected email protected n also the root mean square rms values of these deviations across all file types studied in this paper are less than 5 for n 8 in view of these facts the results presented in this paper could be useful in various application domains like the ones mentioned above

an advanced boundary element method for axisymmetric elastodynamic analysis an advanced boundary element method is appropriately combined with the fast fourier transform fft to analyze general axisymmetric problems in frequency domain elastodynamics the problems are characterized by axisymmetric geometry and non axisymmetric boundary conditions boundary quantities are expanded in complex fourier series in the circumferential direction and the problem is efficiently decomposed into a series of problems which are solved by the bem for the fourier coefficients of the boundary quantities discretizing only the surface generator of the axisymmetric body quadratic boundary elements are used and bem integrations are done by fft algorithm in the circumferential direction and by gauss quadrature in the generator direction singular integrals are evaluated directly in a highly accurate way the fourier transformed solution is then numerically inverted by the fft to provide the final solution the method combines high accuracy and efficiency and this is demonstrated by illustrative numerical examples

evaluation of the helmholtz boundary integral equation and its normal and tangential derivatives in two dimensions abstract this paper presents a means of evaluating singular integrals in the helmholtz boundary integral equation and its normal and tangential derivatives in two dimensions the subtraction addition technique is applied to the singular integral equations to convert the singular integrals to either ordinary integrals with bounded integrands or modified singular integrals including hypersingular integrals with exact integration values this regularization is performed before any discretization the modified integral equations can be calculated by directly applying standard quadrature rules over the entire integration domain numerical computations involve evaluating the acoustic field associated with a radiating inverse elliptic cylinder the velocity potential is obtained by applying the burton miller method which linearly combines the helmholtz boundary integral equation with its normal derivative to treat the fictitious characteristic frequencies further substituting the velocity potential into the regularized tangential derivative yields the surface tangential velocity comparing the numerical results with the analytical solutions verifies the effectiveness of the presented approach

extension of an entropy property for binary input memoryless symmetric channels the channel output entropy property introduced by a d wyner and j ziv ibid vol it 19 p 769 762 nov 1973 for a binary symmetric channel is extended to arbitrary memoryless symmetric channels with binary inputs and discrete or continuous outputs this yields lower bounds on the achievable information rates of these channels under constrained binary inputs using the interpretation of entropy as a measure of order and randomness the authors deduce that output sequences of memoryless symmetric channels induced by binary inputs are of a higher degree of randomness if the redundancy of the input binary sequence is spread in memory rather than in one dimensional asymmetry it is of interest to characterize the general class of schemes for which this interpretation holds

point processes and queues martingale dynamics i martingales 1 histories and stopping times 2 martingales 3 predictability 4 square integrable martingales references solutions to exercises chapter i ii point processes queues and intensities 1 counting processes and queues 2 watanabe s characterization 3 stochastic intensity general case 4 predictable intensities 5 representation of queues 6 random changes of time 7 cryptographic point processes references solutions to exercises chapter ii iii integral representation of point process martingales 1 the structure of internal histories 2 regenerative form of the intensity 3 the representation theorem 4 hilbert space theory of poissonian martingales 5 useful extensions references solutions to exercises chapter iii iv filtering 1 the theory of innovations 2 state estimates for queues and markov chains 3 continuous states and nontrivial prehistory references solutions to exercises chapter iv v flows in markovian networks of queues 1 single station the historical results and the filtering method 2 jackson s networks 3 burke s output theorem for networks 4 cascades and loops in jackson s networks 5 independence and poissonian flows in markov chains references solutions to exercises chapter v vi likelihood ratios 1 radon nikodym derivatives and tests of hypotheses 2 changes of intensities a la girsanov 3 filtering by the method of the probability of reference 4 applications 5 the capacity of a point process channel 6 detection formula187 references189 solutions to exercises chapter vi vii optimal control 1 modeling intensity controls 2 dynamic programming for intensity controls complete observation case 3 input regulation a case study in impulsive control 4 attraction controls 5 existence via likelihood ratio references solutions to exercises chapter vii viii marked point processes 1 counting measure and intensity kernels 2 martingale representation and filtering 3 radon nikodym derivatives 4 towards a general theory of intensity references solutions to exercises chapter viii a1 background in probability and stochastic processes 1 introduction 2 monotone class theorem 3 random variables 4 expectations 5 conditioning and independence 6 convergence 7 stochastic processes 8 markov processes references a2 stopping times and point process histories 1 stopping times 2 changes of time and meyer dellacherie s integration formula 3 point process histories references a3 wiener driven dynamical systems 1 ito s stochastic integral 2 square integrable brownian martingales 3 girsanov s theorem references a4 stieltjes lebesgue calculus 1 the stieltjes lebesgue integral 2 the product and exponential formulas references general bibliography

a boundary integral method for acoustic radiation and scattering in this article a computational method is proposed for computing the helmholtz integral equation for acoustic radiation and scattering problems with a three dimensional body shape unlike the previous boundary element method the integration of acoustic properties is based on the global body surface instead of local elements the approximation function of body geometry and the weighting function of numerical integration are independently chosen when the singular kernels of helmholtz equation are regularized as bounded discontinuous functions the order of integration polynomials for acoustic properties can be arbitrarily chosen therefore the accuracy and efficiency of computation can be increased