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Normal Form Algorithms for Extended ContextFree Grammars
 Theoretical Computer Science
, 2000
"... We investigate the complexity of a variety of normalform transformations for extended contextfree grammars, where by extended we mean that the set of righthand sides for each nonterminal in such a grammar is a regular set. The study is motivated by the implementation project GraMa which will p ..."
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Cited by 18 (2 self)
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We investigate the complexity of a variety of normalform transformations for extended contextfree grammars, where by extended we mean that the set of righthand sides for each nonterminal in such a grammar is a regular set. The study is motivated by the implementation project GraMa which will provide a C++ toolkit for the symbolic manipulation of contextfree objects just as Grail does for regular objects. Our results generalize known complexity bounds for contextfree grammars but do so in nontrivial ways. Specifically, we introduce a new representation scheme for extended contextfree grammars (the symbolthreaded expression forest), a new normal form for these grammars (dot normal form) and new regular expression algorithms. 1 Introduction In the 1960's, extended contextfree grammars were introduced, based on BackusNaur form, as a useful abbreviatory notation that made contextfree grammars easier to write. More recently, the Standardized General Markup Language (SGML...
Interactive manipulation of regular objects with FAdo
 In Proceedings of 2005 Innovation and Technology in Computer Science Education (ITiCSE 2005). ACM
, 2005
"... FAdo 1 is an ongoing project which aims the development of an interactive environment for symbolic manipulation of formal languages. In this paper we focus in the description of interactive tools for teaching and assisting research on regular languages, and in particular finite automata and regular ..."
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Cited by 10 (7 self)
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FAdo 1 is an ongoing project which aims the development of an interactive environment for symbolic manipulation of formal languages. In this paper we focus in the description of interactive tools for teaching and assisting research on regular languages, and in particular finite automata and regular expressions. Those tools implement most standard automata operations, conversion between automata and regular expressions, and word recognition. We illustrate their use in training and automatic assessment. Finally we present a graphical environment for editing and interactive visualisation.
Assembling Molecules in Atomix is Hard
, 2001
"... . It is shown that assembling molecules in the Atomix game can be used to simulate nite automata. In particular, an instance of Atomix is constructed that has a solution if and only if the nonemptiness intersection problem for nite automata is solvable. This shows that the game under considerat ..."
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Cited by 10 (1 self)
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. It is shown that assembling molecules in the Atomix game can be used to simulate nite automata. In particular, an instance of Atomix is constructed that has a solution if and only if the nonemptiness intersection problem for nite automata is solvable. This shows that the game under consideration is PSPACEcomplete, improving a recent result of Huner et al. [9]. Thus, there are Atomix games which have superpolynomially long optimal solutions. We also give an easy construction of Atomix game levels whose optimal solutions meet the worst case. 1
Policydriven memory protection for reconfigurable systems
 In Proceedings of the European Symposium on Research in Computer Security (ESORICS
, 2006
"... Abstract. While processor based systems often enforce memory protection to prevent the unintended sharing of data between processes, current systems built around reconfigurable hardware typically offer no such protection. Several reconfigurable cores are often integrated onto a single chip where the ..."
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Cited by 10 (6 self)
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Abstract. While processor based systems often enforce memory protection to prevent the unintended sharing of data between processes, current systems built around reconfigurable hardware typically offer no such protection. Several reconfigurable cores are often integrated onto a single chip where they share external resources such as memory. While this enables small form factor and low cost designs, it opens up the opportunity for modules to intercept or even interfere with the operation of one another. We investigate the design and synthesis of a memory protection mechanism capable of enforcing policies expressed as a formal language. Our approach includes a specialized compiler that translates a policy of legal sharing to reconfigurable logic blocks which can be directly transferred to an FPGA. The efficiency of our access language design flow is evaluated in terms of area and cycle time across a variety of security scenarios.
Subset construction complexity for homogeneous automata, position automata and ZPCstructures
 Theoretical Computer Science
, 2001
"... The aim of this paper is to investigate how subset construction performs on specific families of automata. A new upper bound on the number of states of the subsetautomaton is established in the case of homogeneous automata. The complexity of the two basic steps of subset construction, i.e. the comp ..."
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Cited by 7 (2 self)
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The aim of this paper is to investigate how subset construction performs on specific families of automata. A new upper bound on the number of states of the subsetautomaton is established in the case of homogeneous automata. The complexity of the two basic steps of subset construction, i.e. the computation of deterministic transitions and the set equality tests, is examined depending on whether the nondeterministic automaton is an unrestricted one, an homogeneous one, a position one or a ZPCstructure, which is an implicit construction for a position automaton.
FAdo and GUItar: tools for automata manipulation and visualization
 14th CIAA 2009, volume 5642 of LNCS
, 2009
"... Abstract. FAdo is an ongoing project which aims to provide a set of tools for symbolic manipulation of formal languages. To allow highlevel programming with complex data structures, easy prototyping of algorithms, and portability (to use in computer grid systems for example), are its main features. ..."
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Cited by 7 (5 self)
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Abstract. FAdo is an ongoing project which aims to provide a set of tools for symbolic manipulation of formal languages. To allow highlevel programming with complex data structures, easy prototyping of algorithms, and portability (to use in computer grid systems for example), are its main features. Our main motivation is the theoretical and experimental research, but we have also in mind the construction of a pedagogical tool for teaching automata theory and formal languages. For the graphical visualization and interactive manipulation a new interface application, GUItar, is being developed. In this paper, we describe the main components of the FAdo system as well as the basics of the graphical interface and editor, the export/import filters and its generic interface with external systems, such as FAdo. 1
State complexity of union and intersection of finite languages
 In Proceedings of DLT’07, Lecture Notes in Computer Science 4588
, 2007
"... Abstract. We investigate the state complexity of union and intersection for finite languages. Note that the problem of obtaining the tight bounds for both operations was open. We compute the upper bounds based on the structural properties of minimal deterministic finitestate automata (DFAs) for fin ..."
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Cited by 4 (2 self)
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Abstract. We investigate the state complexity of union and intersection for finite languages. Note that the problem of obtaining the tight bounds for both operations was open. We compute the upper bounds based on the structural properties of minimal deterministic finitestate automata (DFAs) for finite languages. Then, we show that the upper bounds are tight if we have a variable sized alphabet that can depend on the size of input DFAs. In addition, we prove that the upper bounds are unreachable for any fixed sized alphabet. 1
Extended ContextFree Grammars and Normal Form Algorithms
, 1998
"... We investigate the complexity of a variety of normalform transformations for extended contextfree grammars, where by extended we mean that the set of righthand sides for each nonterminal in such a grammar is a regular set. The study is motivated by the implementation project GraMa which will prov ..."
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Cited by 3 (2 self)
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We investigate the complexity of a variety of normalform transformations for extended contextfree grammars, where by extended we mean that the set of righthand sides for each nonterminal in such a grammar is a regular set. The study is motivated by the implementation project GraMa which will provide a C++ toolkit for the symbolic manipulation of contextfree objects just as Grail does for regular objects. Our results generalize known bounds for contextfree grammars but do so in nontrivial ways. Specifically, we introduce a new representation scheme for extended contextfree grammars (the symbolthreaded expression forest), a new normal form for these grammars (dot normal form) and new regular expression algorithms. 1 Introduction in the 1960's, extended contextfree grammars were introduced, using BackusNaur form, as a useful abbreviatory notation that made contextfree grammars easier to write. More recently, the Standardized General Markup Language (SGML) [13] used a similar ab...
Transition Diagram Systems and Normal Form Algorithms
, 1998
"... We investigate the complexity of a variety of normalform transformations for transition diagram systems, which are a parsing view of extended contextfree grammars. A transition diagram system is a finite collection of finitestate machines each of which is labeled with a unique nonterminal symbol. ..."
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Cited by 1 (1 self)
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We investigate the complexity of a variety of normalform transformations for transition diagram systems, which are a parsing view of extended contextfree grammars. A transition diagram system is a finite collection of finitestate machines each of which is labeled with a unique nonterminal symbol. The study is motivated by the implementation project GraMa which will provide a C++ toolkit for the symbolic manipulation of contextfree objects just as Grail does for regular objects. 1 Introduction In the 1960's, extended contextfree grammars (as BackusNaur form) were introduced as a useful abbreviatory notation that made contextfree grammars easier to write. More recently, the Standardized General Markup Language (SGML) [17] used a similar abbreviatory notation to define extended contextfree grammars for documents. Currently, XML [4], which is a simplified version of SGML, is being promoted as the markup language for the web, instead of HTML (a specific grammar or DTD specified us...
A Reexamination of the Glushkov and Thompson Constructions
, 1998
"... We reexamine the relationship between the two most popular methods for transforming a regular expression into a finitestate machine: the Glushkov and Thompson constructions. These methods have received more attention recently because of the Standard Generalized Markup Language (SGML) and a revival ..."
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Cited by 1 (0 self)
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We reexamine the relationship between the two most popular methods for transforming a regular expression into a finitestate machine: the Glushkov and Thompson constructions. These methods have received more attention recently because of the Standard Generalized Markup Language (SGML) and a revival of interest in symbolic toolkits for regular and contextfree expressions, grammars, and machines. We establish that: ffl Every Thompson machine is, in a sense we make precise, a Glushkov machine ffl Every Glushkov machine is hidden in the corresponding Thompson machine 1 Introduction Inductive construction of finitestate machines from regular expressions are a popular implementation technique in system utilities, such as awk and grep, and in software tools for regularexpression manipulation such as AMoRE [12], AUTOMATE [6] and Grail [13]. When implementing regularexpression tools the regular expressions are usually, but not always, compiled into an executable form based on finitestat...