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74
PRIX: Indexing And Querying XML Using Prufer Sequences
 In ICDE
, 2003
"... We propose a new way of indexing XML documents and processing twig patterns in an XML database. ..."
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Cited by 49 (6 self)
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We propose a new way of indexing XML documents and processing twig patterns in an XML database.
Coalescent Random Forests
 J. COMBINATORIAL THEORY A
, 1998
"... Various enumerations of labeled trees and forests, including Cayley's formula n n\Gamma2 for the number of trees labeled by [n], and Cayley's multinomial expansion over trees, are derived from the following coalescent construction of a sequence of random forests (R n ; R n\Gamma1 ; : ..."
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Cited by 39 (18 self)
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Various enumerations of labeled trees and forests, including Cayley's formula n n\Gamma2 for the number of trees labeled by [n], and Cayley's multinomial expansion over trees, are derived from the following coalescent construction of a sequence of random forests (R n ; R n\Gamma1 ; : : : ; R 1 ) such that R k has uniform distribution over the set of all forests of k rooted trees labeled by [n]. Let R n be the trivial forest with n root vertices and no edges. For n k 2, given that R n ; : : : ; R k have been defined so that R k is a rooted forest of k trees, define R k\Gamma1 by addition to R k of a single edge picked uniformly at random from the set of n(k \Gamma 1) edges which when added to R k yield a rooted forest of k \Gamma 1 trees. This coalescent construction is related to a model for a physical process of clustering or coagulation, the additive coalescent in which a system of masses is subject to binary coalescent collisions, with each pair of masses of magnitude...
FiST: Scalable XML Document Filtering by Sequencing Twig Patterns
 IN PROC. OF VLDB
, 2005
"... In recent years, publishsubscribe (pubsub) systems based on XML document filtering have received much attention. In a typical pubsub system, subscribed users specify their interest in profiles expressed in the XPath language, and each new content is matched against the user profiles so that ..."
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Cited by 29 (4 self)
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In recent years, publishsubscribe (pubsub) systems based on XML document filtering have received much attention. In a typical pubsub system, subscribed users specify their interest in profiles expressed in the XPath language, and each new content is matched against the user profiles so that the content is delivered to only the interested subscribers. As the number of subscribed users and their profiles can grow very large, the scalability of the system is critical to the success of pubsub services. In this
Redundant representations in evolutionary computation
 EVOLUTIONARY COMPUTATION
, 2003
"... This paper investigates how the use of redundant representations influences the performance of genetic and evolutionary algorithms. Representations are redundant if the number of genotypes exceeds the number of phenotypes. A distinction is made between synonymously and nonsynonymously redundant ..."
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Cited by 27 (2 self)
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This paper investigates how the use of redundant representations influences the performance of genetic and evolutionary algorithms. Representations are redundant if the number of genotypes exceeds the number of phenotypes. A distinction is made between synonymously and nonsynonymously redundant representations. Representation are synonymously redundant if the genotypes that represent the same phenotype are very similar to each other. Nonsynonymously redundant representations do not allow genetic operators to work properly and result in a lower performance of evolutionary search. When using synonymously redundant representations, the performance of selectorecombinative genetic algorithms (GAs) depends on the modification of the initial supply. Theoretical models are developed that show the necessary population size to solve a problem and the number of generations goes with O(2 /r), where k r is the order of redundancy and r is the number of genotypic building blocks (BB) that represent the optimal phenotypic BB. Therefore, uniformly redundant representations do not change the behavior of GAs. Only by increasing r, which means overrepresenting the optimal solution, does GA performance increase. Therefore, nonuniformly redundant representations can only be used advantageously if apriori information exists regarding the optimal solution. The validity of the proposed theoretical concepts is illustrated for the binary trivial voting mapping and the realvalued linkbiased encoding. The empirical investigations show that the developed population sizing and time to convergence models allow an accurate prediction of the empirical results.
Determinant factorization: A new encoding scheme for spanning trees applied to the probabilistic minimum spanning tree problem
 In Eschelman, L. (Ed.), Proceedings of the S9cth International Conference on Genetic Algorithms
, 1995
"... This paper describes a new encoding scheme for the representation of spanning trees. This new encoding scheme is based on the factorization of the determinant of the indegree matrix of the original graph. Each factor represents a spanning tree if the determinant corresponding to that factor is equa ..."
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Cited by 20 (0 self)
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This paper describes a new encoding scheme for the representation of spanning trees. This new encoding scheme is based on the factorization of the determinant of the indegree matrix of the original graph. Each factor represents a spanning tree if the determinant corresponding to that factor is equal to one. Our new determinant encoding will be compared to the Prufer encoding, and to the node and link biased encoding by solving an NPcomplete variation of the minimum spanning tree problem, known as the Probabilistic Minimum Spanning Tree Problem. Given a connected graph G(V,E), a cost function c:E;!< +, and a probability function P:2V;![0 � 1], the problem is to nd an a priori spanning tree of minimum expected length. Our results show a signi cant improvement in using the new determinant encoding and the node and link biased encoding compared to Prufer's encoding. We also show empirically that our new determinant encoding scheme is as good as the node and link biased encoding. Our new determinant encoding works very well for restricted spanning trees, and for incomplete graphs. 1
Kalmanextended genetic algorithm for search in nonstationary environments with noisy fitness evaluations
 IEEE Transactions on Evolutionary Computation
, 2001
"... Abstract In basic genetic algorithm (GA) applications, the fitness of a solution takes a value that is certain and unchanging. There are two classes of problem for which this formulation is insufficient. The first consists of ongoing searches for better solutions in a nonstationary environment, wh ..."
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Cited by 15 (0 self)
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Abstract In basic genetic algorithm (GA) applications, the fitness of a solution takes a value that is certain and unchanging. There are two classes of problem for which this formulation is insufficient. The first consists of ongoing searches for better solutions in a nonstationary environment, where the expected fitness of a solution changes with time in unpredictable ways. The second class consists of applications in which fitness evaluations are corrupted by noise. For problems belonging to either or both of these classes, the estimated fitness of a solution will have an associated uncertainty. Both the uncertainty due to environmental changes (process noise) and the uncertainty due to noisy evaluations (observation noise) can be reduced, at least temporarily, by reevaluating existing solutions. The Kalman formulation provides a welldeveloped formal mechanism for treating uncertainty within the GA framework. It provides the mechanics for determining the estimated fitness and uncertainty when a new solution is generated and evaluated for the first time. It also provides the mechanics for updating the estimated fitness and uncertainty after an existing solution is reevaluated, and for increasing the uncertainty with the passage of time. A Kalmanextended genetic algorithm (KGA) is developed to determine when to generate a new individual, when to reevaluate an existing individual, and which one to reevaluate. This KGA is applied to the problem of maintaining a network configuration with minimized message
EdgeSets: An Effective Evolutionary Coding of Spanning Trees
, 2002
"... The fundamental design choices in an evolutionary algorithm are its representation of candidate solutions and the operators that will act on that representation. We propose representing spanning trees in evolutionary algorithms for network design problems directly as sets of their edges, and we d ..."
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Cited by 15 (7 self)
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The fundamental design choices in an evolutionary algorithm are its representation of candidate solutions and the operators that will act on that representation. We propose representing spanning trees in evolutionary algorithms for network design problems directly as sets of their edges, and we describe initialization, recombination, and mutation operators for this representation. The operators offer
Random mappings, forests, and subsets associated with AbelCayleyHurwitz multinomial expansions
, 2001
"... Various random combinatorial objects, such as mappings, trees, forests, and subsets of a finite set, are constructed with probability distributions related to the binomial and multinomial expansions due to Abel, Cayley and Hurwitz. Relations between these combinatorial objects, such as Joyal&apo ..."
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Cited by 14 (9 self)
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Various random combinatorial objects, such as mappings, trees, forests, and subsets of a finite set, are constructed with probability distributions related to the binomial and multinomial expansions due to Abel, Cayley and Hurwitz. Relations between these combinatorial objects, such as Joyal's bijection between mappings and marked rooted trees, have interesting probabilistic interpretations, and applications to the asymptotic structure of large random trees and mappings. An extension of Hurwitz's binomial formula is associated with the probability distribution of the random set of vertices of a fringe subtree in a random forest whose distribution is defined by terms of a multinomial expansion over rooted labeled forests. Research supported in part by N.S.F. Grants DMS 9703961 and DMS0071448 1 Contents 1
AbelCayleyHurwitz multinomial expansions associated with random mappings, forests, and subsets
, 1998
"... Extensions of binomial and multinomial formulae due to Abel, Cayley and Hurwitz are related to the probability distributions of various random subsets, trees, forests, and mappings. For instance, an extension of Hurwitz's binomial formula is associated with the probability distribution of the r ..."
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Cited by 13 (12 self)
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Extensions of binomial and multinomial formulae due to Abel, Cayley and Hurwitz are related to the probability distributions of various random subsets, trees, forests, and mappings. For instance, an extension of Hurwitz's binomial formula is associated with the probability distribution of the random set of vertices of a fringe subtree in a random forest whose distribution is defined by terms of a multinomial expansion over rooted labeled forests which generalizes Cayley's expansion over unrooted labeled trees. Contents 1 Introduction 2 Research supported in part by N.S.F. Grant DMS9703961 2 Probabilistic Interpretations 5 3 Cayley's multinomial expansion 11 4 Random Mappings 14 4.1 Mappings from S to S : : : : : : : : : : : : : : : : : : : : : : : : : : : : 15 4.2 The random set of cyclic points : : : : : : : : : : : : : : : : : : : : : : : 18 5 Random Forests 19 5.1 Distribution of the roots of a pforest : : : : : : : : : : : : : : : : : : : : 19 5.2 Conditioning on the set...