Book•
An Introduction to Automata Theory
01 Mar 1988-
TL;DR: Great Aunt Eugenia and other automata Sundry machines Implementing finite automata Implementation and realization Behavioural equivalence, SP partitions and reduced machines
Abstract: Great Aunt Eugenia and other automata Sundry machines Implementing finite automata Implementation and realization Behavioural equivalence, SP partitions and reduced machines Parallel and serial composition of automata The parallel decomposition theorem The serial decomposition theorem The lattice of SP partitions Analysis of machines Concurrent systems: net theory Concurrent systems: the calculus of communicating systems. Appendix: Sets, relations and functions.
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Book•
01 Jan 1996TL;DR: This chapter surveys the theory of two-party communication complexity and presents results regarding the following models of computation: • Finite automata • Turing machines • Decision trees • Ordered binary decision diagrams • VLSI chips • Networks of threshold gates.
Abstract: In this chapter we survey the theory of two-party communication complexity. This field of theoretical computer science aims at studying the following, seemingly very simple, scenario: There are two players Alice who holds an n-bit string x and Bob who holds an n-bit string y. Their goal is to communicate in order to compute the value of some boolean function f(x, y), while exchanging a number of bits which is as small as possible. In the first part of this survey we present, mainly by giving examples, some of the results (and techniques) developed as part of this theory. We put an emphasis on proving lower bounds on the amount of communication that must be exchanged in the above scenario for certain functions f . In the second part of this survey we will exemplify the wide applicability of the results proved in the first part to other areas of computer science. While it is obvious that there are many applications of the results to problems in which communication is involved (e.g., in distributed systems), we concentrate on applications in which communication does not appear explicitly in the statement of the problems. In particular, we present results regarding the following models of computation: • Finite automata • Turing machines • Decision trees • Ordered binary decision diagrams (OBDDs) • VLSI chips • Networks of threshold gates We provide references to many other issues and applications of communication complexity which are not discussed in this survey.
2,004 citations
Cites background from "An Introduction to Automata Theory"
...For formal definitions of finite automata and many of their properties, including the transformation of nondeterministic automata into deterministic automata, the reader is referred to any of the standard texts in this area (e.g., [Hopcroft and Ullman 1979])....
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...(Again, for formal definitions of Turing machines, as well as the notions of time and space, the reader is referred to any of the standard texts in computability or complexity, e.g., [Hopcroft and Ullman 1979].)...
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Proceedings Article•
25 Aug 1997TL;DR: The theoretical foundations of DataGuides are presented along with an algorithm for their creation and an overview of incremental maintenance, and performance results based on the implementation of dataGuides in the Lore DBMS for semistructured data are provided.
Abstract: In semistructured databases there is no schema fixed in advance. To provide the benefits of a schema in such environments, we introduce DataGuides: concise and accurate structural summaries of semistructured databases. DataGuides serve as dynamic schemas, generated from the database; they are useful for browsing database structure, formulating queries, storing information such as statistics and sample values, and enabling query optimization. This paper presents the theoretical foundations of DataGuides along with an algorithm for their creation and an overview of incremental maintenance. We provide performance results based on our implementation of DataGuides in the Lore DBMS for semistructured data. We also describe the use of DataGuides in Lore, both in the user interface to enable structure browsing and query formulation, and as a means of guiding the query processor and optimizing query execution.
1,341 citations
Cites background from "An Introduction to Automata Theory"
...That paper proved that creating a DataGuide over a source database is equivalent to conversion of a non-deterministic finite automaton (NFA) to a deterministic finite automaton (DFA), a well -studied problem [HU79]....
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...Unfortunately, no research known to the authors formally identifies those NFAs that do or do not require exponential time or space to be converted to equivalent DFAs....
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...From automata theory, we know that a single NFA may have many equivalent DFAs [HU79]....
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TL;DR: The higraph, a general kind of diagramming object, forms a visual formalism of topological nature that is suited for a wide array of applications to databases, knowledge representation, and the behavioral specification of complex concurrent systems using the higraph-based language of statecharts.
Abstract: The higraph, a general kind of diagramming object, forms a visual formalism of topological nature. Higraphs are suited for a wide array of applications to databases, knowledge representation, and, most notably, the behavioral specification of complex concurrent systems using the higraph-based language of statecharts.
1,332 citations
31 Aug 2004
TL;DR: This paper proposes techniques to semi-automatically separate reputable, good pages from spam, and shows that they can effectively filter out spam from a significant fraction of the web, based on a good seed set of less than 200 sites.
Abstract: Web spam pages use various techniques to achieve higher-than-deserved rankings in a search engine's results. While human experts can identify spam, it is too expensive to manually evaluate a large number of pages. Instead, we propose techniques to semi-automatically separate reputable, good pages from spam. We first select a small set of seed pages to be evaluated by an expert. Once we manually identify the reputable seed pages, we use the link structure of the web to discover other pages that are likely to be good. In this paper we discuss possible ways to implement the seed selection and the discovery of good pages. We present results of experiments run on the World Wide Web indexed by AltaVista and evaluate the performance of our techniques. Our results show that we can effectively filter out spam from a significant fraction of the web, based on a good seed set of less than 200 sites.
1,259 citations
Cites background from "An Introduction to Automata Theory"
...2The general problem of identifying the minimal set of pages that yields maximum coverage is equivalent to the independent set problem [7] on directed graphs as shown next....
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03 Sep 2001
TL;DR: The paper provides a sound and complete set of inference rules and a cubic time algorithm for determining implication of the keys in a key constraint language for XML.
Abstract: The paper proposes a key constraint language for XML and investigates its associated decision problems. The language is defined in terms of regular path expressions extended with downward and upward wildcards, which can not only move down XML document trees, but also upwards. In a uniform syntax it is capable of expressing both absolute keys and relative keys, which are important to hierarchically structured data. In addition, keys defined in the language can be reasoned about efficiently. The paper provides a sound and complete set of inference rules and a cubic time algorithm for determining implication of the keys.
1,206 citations