An upper bound on the probability of a sequence drawn from a finite-state source is derived. The bound is given in terms of the number of phrases obtained by parsing the sequence according to the lempel-ziv (L-Z) incr...
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An upper bound on the probability of a sequence drawn from a finite-state source is derived. The bound is given in terms of the number of phrases obtained by parsing the sequence according to the lempel-ziv (L-Z) incremental parsing rule, and is universal in the sense that it does not depend on the statistical parameters that characterize the source. This bound is used to derive an upper bound on the redundancy of the L-Z universal data compression algorithm applied to finite-state sources, that depends on the length N of the sequence, on the number K of states of the source, and, eventually, on the source entropy. A variation of the L-Z algorithm is presented, and an upper bound on its redundancy is derived for finite-state sources. A method to derive tighter implicit upper bounds on the redundancy of both algorithms is also given, and it is shown that for the proposed variation this bound is smaller than for the original L-Z algorithm, or every value of N and K.
A new analysis shows that, when we apply the lempel-ziv incremental parsing algorithm to an i.i.d., source with probabilities pi, i = 1, . . ., m, the expected length E\W(t)\ of the tth parsed segment W(t) is given by...
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A new analysis shows that, when we apply the lempel-ziv incremental parsing algorithm to an i.i.d., source with probabilities pi, i = 1, . . ., m, the expected length E\W(t)\ of the tth parsed segment W(t) is given by ( t/n ) SIGMA(n = 1)t (-1) n - 1 PI(l = 2)n (1 - SIGMA(i = 1)m p(i)l), with the null product being 1. It is also shown that lim(t --> infinity) E\W(t)\/logt = H(X)-1 for the same source with the entropy H(X). This gives a variable-to-fixed length (VF) scheme version of the ziv-lempel universal coding theorem.
Precipitation is an important part of the hydrologic cycle, and its complexity is closely related to surface runoff and changing groundwater dynamics, which in turn influences the accuracy of precipitation forecasts. ...
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Precipitation is an important part of the hydrologic cycle, and its complexity is closely related to surface runoff and changing groundwater dynamics, which in turn influences the accuracy of precipitation forecasts. In this study, we used the lempel-ziv algorithm (LZA) and a multi-scaling approach to assess precipitation complexity for 1958-2011 by analyzing time series data from 28 gauging stations located throughout Jilin province, China. The spatial distribution of normalized precipitation complexity was measured by LZA, a symbolic dynamics algorithm, and by a multi-scaling approach, which is described by fractals. In addition, the advantages and limitations of these two methods were investigated. The results indicate that both methods are applicable and consistent for calculating precipitation complexity, and that the degree of relief is a primary factor controlling precipitation complexity in the mountainous area;in the plain terrain, however, the prominent influencing factor is climate.
We derive several almost-sure results related to the sliding-window lempel-ziv (SWLZ) algorithm. A principal result is a path-wise lower bound to the redundancy equal to 1/2h log(2) log(2) n(w)/log(2) n(w) in the main...
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We derive several almost-sure results related to the sliding-window lempel-ziv (SWLZ) algorithm. A principal result is a path-wise lower bound to the redundancy equal to 1/2h log(2) log(2) n(w)/log(2) n(w) in the main term, where n(w) is the sliding window size. This bound is off by a factor of two from the main term in the lower bound of A. J. Wyner and the work of Yang and Kieffer, which hold in the expected sense for the fixed-database lempel-ziv algorithm (FDLZ). Another aspect of the present work studies the asymptotic behavior of the ratio of the number of phrases to the length of the parsed string for any finite sliding Window size;in here we exploit the theory of asymptotic mean stationary processes of Gray and Kieffer and some results of Kieffer and Rahe. In all cases it is assumed that the source is stationary and that in the most restrictive case it is an irreducible and aperiodic Markov chain;some of the results hold for sources that have exponential rates for entropy and more generally for the ergodic setting.
Two universal lossy data compression schemes, one with fixed rate and the other with fixed distortion, are presented, based on the well-known lempel-ziv algorithm. In the case of fixed rate R, our universal lossy data...
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Two universal lossy data compression schemes, one with fixed rate and the other with fixed distortion, are presented, based on the well-known lempel-ziv algorithm. In the case of fixed rate R, our universal lossy data compression scheme works as follows: first pick a codebook B-n consisting of all reproduction sequences of length n whose lempel-ziv codeword length is less than or equal to nR, and then use B1 to encode the entire source sequence n-block by n-block. This fixed-rate data compression scheme is universal in the sense that for any stationary, ergodic source or for any individual sequence, the sample distortion performance as n --> infinity is given almost surely by the distortion rate function. A similar result is shown in the context of fixed distortion lossy source coding.
The problem of non-distorting compression (or coding) of sequences of symbols is considered. For sequences of asymptotically zero empirical entropy, a modification of the lempel-ziv coding rule is offered whose coding...
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The problem of non-distorting compression (or coding) of sequences of symbols is considered. For sequences of asymptotically zero empirical entropy, a modification of the lempel-ziv coding rule is offered whose coding cost is at most a finite number of times worse than the optimum. A combinatorial proof is offered for the well-known redundancy estimate of the lempel-ziv coding algorithm for sequences having a positive entropy. (C) 2002 Elsevier B.V. All rights reserved.
The fixed-database version of the lempel-ziv algorithm closely resembles many versions that appear in practice, In this paper, we ascertain several key asymptotic properties of the algorithm as applied to sources with...
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The fixed-database version of the lempel-ziv algorithm closely resembles many versions that appear in practice, In this paper, we ascertain several key asymptotic properties of the algorithm as applied to sources with finite memory, First, we determine that for a dictionary of size n, the algorithm achieves a redundancy rho(n) = H log log n/log n + o (log log n/log n) where H is the entropy of the process, This is the first, nontrivial, lower bound on any lempel-ziv-type compression scheme, We then find the limiting distribution and all moments of the lengths of the phrases by comparing them to a random-walk-like variable with well-known behavior.
We derive several almost-sure results related to the sliding-window lempel-ziv (SWLZ) algorithm. A principal result is a path-wise lower bound to the redundancy equal to 1/2h log(2) log(2) n(w)/log(2) n(w) in the main...
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We derive several almost-sure results related to the sliding-window lempel-ziv (SWLZ) algorithm. A principal result is a path-wise lower bound to the redundancy equal to 1/2h log(2) log(2) n(w)/log(2) n(w) in the main term, where n(w) is the sliding window size. This bound is off by a factor of two from the main term in the lower bound of A. J. Wyner and the work of Yang and Kieffer, which hold in the expected sense for the fixed-database lempel-ziv algorithm (FDLZ). Another aspect of the present work studies the asymptotic behavior of the ratio of the number of phrases to the length of the parsed string for any finite sliding Window size;in here we exploit the theory of asymptotic mean stationary processes of Gray and Kieffer and some results of Kieffer and Rahe. In all cases it is assumed that the source is stationary and that in the most restrictive case it is an irreducible and aperiodic Markov chain;some of the results hold for sources that have exponential rates for entropy and more generally for the ergodic setting.
We study lempel-ziv-Yokoo algorithm [1,algorithm 4] for universal data compression. In this paper, we give a simpler implementation of lempel-ziv-Yokoo algorithm than the original one[l,algorithm 4] and show its asymp...
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We study lempel-ziv-Yokoo algorithm [1,algorithm 4] for universal data compression. In this paper, we give a simpler implementation of lempel-ziv-Yokoo algorithm than the original one[l,algorithm 4] and show its asymptotic optimality for a stationary ergodic source.
We establish a coding theorem and a matching converse theorem for separate encodings and joint decoding of individual sequences using finite-state machines. The achievable rate region is characterized in terms of the ...
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We establish a coding theorem and a matching converse theorem for separate encodings and joint decoding of individual sequences using finite-state machines. The achievable rate region is characterized in terms of the lempel-ziv (LZ) complexities, the conditional LZ complexities and the joint LZ complexity of the two source sequences. An important feature that is needed to this end, which may be interesting on its own right, is a certain asymptotic form of a chain rule for LZ complexities, which we establish in this work. The main emphasis in the achievability scheme is on the universal decoder and its properties. We then show that the achievable rate region is universally attainable by a modified version of Draper's universal incremental Slepian-Wolf (SW) coding scheme, provided that there exists a low-rate reliable feedback link.
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