45 research outputs found

    Construction of a Pushdown Automaton Accepting a Postfix Notation of a Tree Language Given by a Regular Tree Expression

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    Regular tree expressions are a formalism for describing regular tree languages, which can be accepted by a finite tree automaton as a standard model of computation. It was proved that the class of regular tree languages is a proper subclass of tree languages whose linear notations can be accepted by deterministic string pushdown automata. In this paper, we present a new algorithm for transforming regular tree expressions to equivalent real-time height-deterministic pushdown automata that accept the trees in their postfix notation

    Target Code Selection by Tilling AST with the Use of Tree Pattern Pushdown Automaton

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    A new and simple method for target code selection by tilling an abstract syntax tree is presented. As it is usual, tree patterns corresponding to target machine instructions are matched in the abstract syntax tree. Matching tree patterns is performed with the use of tree pattern pushdown automaton, which accepts all tree patterns matching the abstract syntax tree in the linear postfix bar notation and represents a full index of the abstract syntax tree for tree patterns. The use of the index allows to match patterns quickly, in time depending on the size of patterns and not depending on the size of the tree. The selection of a particular target instruction corresponds to a modification of the abstract syntax tree and also a corresponding incremental modification of the index is performed. A reference to a fully functional prototype is provided

    Indications and management of implantable cardioverter-defibrillator therapy in childhood hypertrophic cardiomyopathy

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    Sudden cardiac death is the most common mode of death during childhood and adolescence in hypertrophic cardiomyopathy, and identifying those individuals at highest risk is a major aspect of clinical care. The mainstay of preventative therapy is the implantable cardioverter-defibrillator, which has been shown to be effective at terminating malignant ventricular arrhythmias in children with hypertrophic cardiomyopathy but can be associated with substantial morbidity. Accurate identification of those children at highest risk who would benefit most from implantable cardioverter-defibrillator implantation while minimising the risk of complications is, therefore, essential. This position statement, on behalf of the Association for European Paediatric and Congenital Cardiology (AEPC), reviews the currently available data on established and proposed risk factors for sudden cardiac death in childhood-onset hypertrophic cardiomyopathy and current approaches for risk stratification in this population. It also provides guidance on identification of individuals at risk of sudden cardiac death and optimal management of implantable cardioverter-defibrillators in children and adolescents with hypertrophic cardiomyopathy

    Subtree matching by pushdown automata

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    On modification of Boyer-Moore-horspool's algorithm for tree pattern matching in linearised trees

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    Tree pattern matching on ordered trees is an important problem in Computer Science. Ordered trees can be represented as strings with additional properties via various linearisations. We present a backward tree pattern matching algorithm for ordered trees for various linear representations of trees and tree patterns. The algorithm adaptations find all occurrences of a single given tree pattern which match an input tree regardless of the chosen linearisation. The algorithms preserve the properties and advantages of standard backward string pattern matching using Boyer-Moore-Horspool's bad character shift heuristics. The number of symbol comparisons in the backward tree pattern matching can be sublinear in the size of the input tree. As in the case of the string version of Boyer-Moore-Horspool's matching algorithm, the size of the bad character shift table used by the algorithm is linear in the size of the alphabet. We compare the algorithm adaptations with the algorithm using originally chosen linear representation and with the best performing previously existing algorithms based on (non-linearised) tree pattern matching using finite tree automata or stringpath matchers. We show that the presented backward tree pattern matching algorithms outperform the non-linearising ones for single pattern matching and they perform among themselves comparably

    OASIcs, Volume 74, SLATE\u2719, Complete Volume

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    OASIcs, Volume 74, SLATE\u2719, Complete Volum

    Front Matter, Table of Contents, Preface, Conference Organization

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    Front Matter, Table of Contents, Preface, Conference Organizatio

    Hydroxyl Radical Induced Ultra-Weak Photon Emission from Tyrosine Solutions

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    This paper deals with ultra-weak photon emission (UPE) from aqueous tyrosine solutions induced by hydroxyl radical. The physical nature of this specific phenomenon is presented and the proposed mechanism of its origin during oxidation of tyrosine is described. The experimental part of the work is focused on the measurements of intensity of ultra-weak photon emission from different solutions of tyrosine. The emission from solutions with and without presence of hydroxyl radical is analyzed. The results confirm the assumption that the highest intensity is detected from the solution of tyrosine, hydrogen peroxide and ferrous sulphate heptahydrate, likely due the Fenton reaction originated hydroxyl radical, which causes oxidation of tyrosine, formation of high-energy intermediates and electron excited species. Since hydroxyl radical induced ultra-weak photon emission from tyrosine has not been analyzed before in the available literature, our results could be the beneficial contribution to this field of research
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