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A Survey of Computational Complexity Results in Systems and Control
, 2000
"... The purpose of this paper is twofold: (a) to provide a tutorial introduction to some key concepts from the theory of computational complexity, highlighting their relevance to systems and control theory, and (b) to survey the relatively recent research activity lying at the interface between these fi ..."
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Cited by 187 (21 self)
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The purpose of this paper is twofold: (a) to provide a tutorial introduction to some key concepts from the theory of computational complexity, highlighting their relevance to systems and control theory, and (b) to survey the relatively recent research activity lying at the interface between these fields. We begin with a brief introduction to models of computation, the concepts of undecidability, polynomial time algorithms, NPcompleteness, and the implications of intractability results. We then survey a number of problems that arise in systems and control theory, some of them classical, some of them related to current research. We discuss them from the point of view of computational complexity and also point out many open problems. In particular, we consider problems related to stability or stabilizability of linear systems with parametric uncertainty, robust control, timevarying linear systems, nonlinear and hybrid systems, and stochastic optimal control.
Growth Grammar Interpreter GROGRA 2.4  A software tool for the 3dimensional interpretation of stochastic, sensitive growth grammars in the context of plant modelling
, 1994
"... Introduction and Reference Manual Winfried Kurth Berichte des Forschungszentrums Waldokosysteme Gottingen Ser. B, Vol. 38 Gottingen 1994 Contents Preface iii Introduction 1 1 The role of growth grammars in modelling forest ecosystems 3 1.1 General purposes of modelling . . . . . . . . . . . . ..."
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Cited by 46 (12 self)
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Introduction and Reference Manual Winfried Kurth Berichte des Forschungszentrums Waldokosysteme Gottingen Ser. B, Vol. 38 Gottingen 1994 Contents Preface iii Introduction 1 1 The role of growth grammars in modelling forest ecosystems 3 1.1 General purposes of modelling . . . . . . . . . . . . . . . . . . . . 3 1.2 Systematisation of approaches . . . . . . . . . . . . . . . . . . . . 4 1.3 Purposes of morphological models . . . . . . . . . . . . . . . . . . 7 1.4 The role of GROGRA . . . . . . . . . . . . . . . . . . . . . . . . 10 1.5 Related approaches . . . . . . . . . . . . . . . . . . . . . . . . . . 12 2 Stochastic sensitive growth grammars: Mathematical foundations 19 2.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 2.2 Mathematical definitions . . . . . . . . . . . . . . . . . . . . . . . 24 3 Quick guide for using GROGRA 39 3.1 Installation . . . . . . . . . . . . .
Generating Grammars for Structured Documents Using Grammatical Inference Methods
, 1996
"... Dictionaries, user manuals, encyclopedias, and annual reports are typical examples of structured documents. Structured documents have an internal, usually hierarchical, organization that can be used, for instance, to help in retrieving information from the documents and in transforming documents int ..."
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Cited by 43 (4 self)
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Dictionaries, user manuals, encyclopedias, and annual reports are typical examples of structured documents. Structured documents have an internal, usually hierarchical, organization that can be used, for instance, to help in retrieving information from the documents and in transforming documents into another form. The document structure is typically represented by a contextfree or regular grammar. Many structured documents, however, lack the grammar: the structure of individual documents is known but the general structure of the document class is not available. Examples of this kind of documents include documents that have Standard Generalized Markup Language (SGML) tags but not a Document Type Definition (DTD). In this thesis we present a technique for generating a grammar describing the structure of a given structured document instances. The technique is based on ideas from machine learning. It forms first finitestate automata describing the given instances completely. These automata ...
Regular algebra applied to pathfinding problems
 Journal of the Institute of Mathematics and Applications
, 1975
"... In an earlier paper, one of the authors presented an algebra for formulating and solving extremal path problems. There are striking similarities between that algebra and the algebra of regular languages, which lead one to consider whether the previous results can be generalized—for instance to path ..."
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Cited by 37 (8 self)
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In an earlier paper, one of the authors presented an algebra for formulating and solving extremal path problems. There are striking similarities between that algebra and the algebra of regular languages, which lead one to consider whether the previous results can be generalized—for instance to path enumeration problems—and whether the algebra of regular languages can itself be profitably used for the general study of pathfinding problems. This paper gives affirmative answers to both these questions. 1.
Dynamic systems as tools for analysing human judgement
 THINKING AND RESONING
, 2001
"... With the advent of computers in the experimental labs, dynamic systems have become a new tool for research on problem solving and decision making. A short review of this research is given and the main features of these systems (connectivity and dynamics) are illustrated. To allow systematic approach ..."
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Cited by 25 (12 self)
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With the advent of computers in the experimental labs, dynamic systems have become a new tool for research on problem solving and decision making. A short review of this research is given and the main features of these systems (connectivity and dynamics) are illustrated. To allow systematic approaches to the influential variables in this area, two formal frameworks (linear structural equations and finite state automata) are presented. Besides the formal background, the article sets out how the task demands of system identification and system control can be realised in these environments, and how psychometrically acceptable dependent variables can be derived. The use of computersimulated scenarios in problemsolving research has become increasingly popular during the last 25 years (for a representative collection of papers see, e.g., the two editions from Sternberg & Frensch, 1991, and Frensch & Funke, 1995). This new approach to problem solving seems attractive for several reasons. In contrast to static problems, computersimulated scenarios provide a unique opportunity to study human problemsolving and decisionmaking behaviour when the task environment and subjects ’ actions change concurrently. Subjects can manipulate a specific scenario via a number of input variables (typically ranging from 2 to 20, and in some exceptional instances even up to 2000), and they observe the system’s state changes in a number of output variables. In exploring and/or controlling a system, subjects have to continuously acquire and use knowledge about the internal structure of the system.
On the Power of Circular Splicing Systems and DNA Computability
 Proc. of IEEE Intern. Conf. on Evol. Comput. (ICEC'97
, 1997
"... From a biological motivation of interactions between linear and circular DNA sequences, we propose a new type of splicing models called circular H systems and show that they have the same computational power as Turing machines. It is also shown that there effectively exists a universal circular H sy ..."
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Cited by 22 (5 self)
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From a biological motivation of interactions between linear and circular DNA sequences, we propose a new type of splicing models called circular H systems and show that they have the same computational power as Turing machines. It is also shown that there effectively exists a universal circular H system which can simulate any circular H system with the same terminal alphabet, which strongly suggests a feasible design for a DNA computer based on circular splicing. 1 Introduction Since Adleman's breathtaking paper on molecular (DNA) computing ([1]), there have already been quite a few papers on this challenging topic : [10] shows how to solve NPcomplete problems using DNA, while [3] discusses a design method for simulating a Turing machine by molecular biological techniques and shows how to compute PSPACE, and [4]) gives a methodology for breaking the DES using techniques in genetic engineering. In response to the rapid stream of experimental research on this new computation paradigm...
On the Decomposition of Finite Languages
 Y.S. Han et al. / Intercode Regular Languages
, 1998
"... Representations of finite languages as a product (catenation) of languages are investigated, where the factor languages are "prime", that is, cannot be decomposed further in a nontrivial manner. In general, such prime decompositions are not unique  even the number of factors can vary expo ..."
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Cited by 18 (1 self)
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Representations of finite languages as a product (catenation) of languages are investigated, where the factor languages are "prime", that is, cannot be decomposed further in a nontrivial manner. In general, such prime decompositions are not unique  even the number of factors can vary exponentially. The paper investigates the uniqueness of prime decompositions, as well as the commuting of the factors. Interconnections to languages more general than finite are pointed out. In the case of regular languages, the notion of a decomposition set turns out to be a powerful tool. TUCS Research Group
On Presentations of Algebraic Structures
 in Complexity, Logic and Recursion Theory
, 1995
"... This paper is an expanded version of an part of a series of invited lectures given by the author during May 1995 in Siena, Italy to the COLORET II conference. This work is partially supported by Victoria University IGC and the Marsden Fund for Basic Science under grant VIC509. This paper is dedicat ..."
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Cited by 17 (6 self)
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This paper is an expanded version of an part of a series of invited lectures given by the author during May 1995 in Siena, Italy to the COLORET II conference. This work is partially supported by Victoria University IGC and the Marsden Fund for Basic Science under grant VIC509. This paper is dedicated to the memory of my friend and teacher Chris Ash who contributed so much to effective structure theory and who left us far too young early in 1995
On validation of XML streams using finite state machines
 IN WEBDB 2004
, 2004
"... We study validation of streamed XML documents by means of finite state machines. Previous work has shown that validation is in principle possible by finite state automata, but the construction was prohibitively expensive, giving an exponentialsize nondeterministic automaton. Instead, we want to fin ..."
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Cited by 16 (0 self)
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We study validation of streamed XML documents by means of finite state machines. Previous work has shown that validation is in principle possible by finite state automata, but the construction was prohibitively expensive, giving an exponentialsize nondeterministic automaton. Instead, we want to find deterministic automata for validating streamed documents: for them, the complexity of validation is constant per tag. We show that for a reading window of size one and nonrecursive DTDs with oneunambiguous content (i.e. conforming to the current XML standard) there is an algorithm producing a deterministic automaton that validates documents with respect to that DTD. The size of the automaton is at most exponential and we give matching lower bounds. To capture the possible advantages offered by reading windows of size k, we introduce kunambiguity as a generalization of oneunambiguity, and study the validation against DTDs with kunambiguous content. We also consider recursive DTDs and give conditions under which they can be validated against by using onecounter automata.