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On Digital Images Which Cannot be Generated by Small Generalised Stochastic Automata
 In Proc. MFCS Workshop on Randomised Algorithms
, 1998
"... It is known, chiefly through the work of Culik and Kari that generalised stochastic automata (GSA) can be used to compress digital (pixel) images. A theoretical account of GSAbased image compression has not been carried out. This paper contributes to such an account by exhibiting a family of image ..."
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Cited by 2 (2 self)
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It is known, chiefly through the work of Culik and Kari that generalised stochastic automata (GSA) can be used to compress digital (pixel) images. A theoretical account of GSAbased image compression has not been carried out. This paper contributes to such an account by exhibiting a family of images such that a member image having S pixels cannot be generated by a generalised stochastic automaton having fewer than approximately S 1=2 states. This lower bound on the number of states holds even when a certain type of loss is permitted. These images are deterministically defined and are based on work of Ablayev. 1 Introduction Culik and Kari were the first to observe that digital images could be generated by generalised stochastic automata (GSA), and that in some cases lossy compression of an image could be obtained by regarding a GSA as a representation for the image that it `nearly' reproduces. Culik and Kari used the term weighted finite automaton (WFA), rather than than GSA, bu...
A Recursive GSA Acquisition Algorithm for Image Compression
, 1997
"... Culik and Kari introduced the use of generalised stochastic automata (GSA) as a method of digital image compression. The construction of a GSA from an image is a kind of automaton acqusition, although with special characteristics because reproduction is not required to be lossless. In this view an i ..."
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Cited by 2 (2 self)
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Culik and Kari introduced the use of generalised stochastic automata (GSA) as a method of digital image compression. The construction of a GSA from an image is a kind of automaton acqusition, although with special characteristics because reproduction is not required to be lossless. In this view an image is a kind of finite formal language. We detail experimental and theoretical results concerning a simple, recursive GSA acqusition algorithm and discuss directions for future research.
An Interlacing Measure for Formal Polynomials with an Application to Languages
, 1998
"... The syntax of most programming languages is largely specified by grammars that generate DCFL. UCFGn can be put in a realworld context by imagining a situation in which one is given two UCFGs (programming language compiler frontends) and asked to decide whether they are equivalent for all programs ..."
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The syntax of most programming languages is largely specified by grammars that generate DCFL. UCFGn can be put in a realworld context by imagining a situation in which one is given two UCFGs (programming language compiler frontends) and asked to decide whether they are equivalent for all programs up to some large number of tokens, say 104.