Computing communities in large networks using random walks.
Convergence behavior of the (1 +, λ) evolution strategy on the ridge functions.
The convergence behavior of (1 +, λ)-ES is investigated at parabolic ridge, sharp ridge, and at the general case of the ridge functions. The progress rate, the distance to the ridge axis, the success rate, and the success probability are used in the analysis. The strong dependency of the (1 + λ)-ES to the initial conditions is shown using parabolic ridge test function when low distances to the ridge axis are chosen as the start value. The progress rate curve and the success probability curve of...
Dynamic programming for reduced NFAs for approximate string and sequence matching
searching for all occurrences of a pattern (string or sequence) in some text, where the pattern can occur with some limited number of errors given by edit distance. Several methods were designed for the approximate string matching that simulate nondeterministic finite automata (NFA) constructed for this problem. This paper presents reduced NFAs for the approximate string matching usable in case, when we are interested only in occurrences having edit distance less than or equal to a given integer,...
Efficient algorithms on the Moore family associated to an implicational system.
Efficient drawing of RNA secondary structure.
Efficient Improvement of Brain-Tharp's Algorithm
Efficient maxima-finding algorithms for random planar samples.
Efficient validation and construction of border arrays and validation of string matching automata
We present an on-line linear time and space algorithm to check if an integer array is the border array of at least one string built on a bounded or unbounded size alphabet . First of all, we show a bijection between the border array of a string and the skeleton of the DFA recognizing , called a string matching automaton (SMA). Different strings can have the same border array but the originality of the presented method is that the correspondence between a border array and a skeleton of SMA...
Efficient validation and construction of border arrays and validation of string matching automata
We present an on-line linear time and space algorithm to check if an integer array f is the border array of at least one string w built on a bounded or unbounded size alphabet Σ. First of all, we show a bijection between the border array of a string w and the skeleton of the DFA recognizing Σ*ω, called a string matching automaton (SMA). Different strings can have the same border array but the originality of the presented method is that the correspondence between a border array and a...
Fuzzy neural network approach to fuzzy polynomials.
In this paper, an architecture of fuzzy neural networks is proposed to find a real root of a dual fuzzy polynomial (if exists) by introducing a learning algorithm. We proposed a learning algorithm from the cost function for adjusting of crisp weights. According to fuzzy arithmetic, dual fuzzy polynomials can not be replaced by a fuzzy polynomials, directly. Finally, we illustrate our approach by numerical examples.
Fuzzy termination criteria in Knapsack Problem algorithms.
Fuzzy rule based termination criteria are introduced in two conventional and exact algorithms solving Knapsack Problems. As a consequence two new solution algorithms are obtained. These algorithms are heuristic ones with a high performance. The efficiency of the algorithms obtained is illustrated by solving some numerical examples.
Heuristic and metaheuristic methods for computing graph treewidth
The notion of treewidth is of considerable interest in relation to NP-hard problems. Indeed, several studies have shown that the tree-decomposition method can be used to solve many basic optimization problems in polynomial time when treewidth is bounded, even if, for arbitrary graphs, computing the treewidth is NP-hard. Several papers present heuristics with computational experiments. For many graphs the discrepancy between the heuristic results and the best lower bounds is still very large. The...
Heuristic and metaheuristic methods for computing graph treewidth
The notion of treewidth is of considerable interest in relation to NP-hard problems. Indeed, several studies have shown that the tree-decomposition method can be used to solve many basic optimization problems in polynomial time when treewidth is bounded, even if, for arbitrary graphs, computing the treewidth is NP-hard. Several papers present heuristics with computational experiments. For many graphs the discrepancy between the heuristic results and the best lower bounds is still very large....
Implementation of directed acyclic word graph
An effective implementation of a Directed Acyclic Word Graph (DAWG) automaton is shown. A DAWG for a text is a minimal automaton that accepts all substrings of a text , so it represents a complete index of the text. While all usual implementations of DAWG needed about 30 times larger storage space than was the size of the text, here we show an implementation that decreases this requirement down to four times the size of the text. The method uses a compression of DAWG elements, i. e. vertices,...
Improvement to the cooperative rules methodology by using the ant colony system algorithm.
The cooperative rules (COR) methodology [2] is based on a combinatorial search of cooperative rules performed over a set of previously generated candidate rule consequents. It obtains accurate models preserving the highest interpretability of the linguistic fuzzy rule-based systems. Once the good behavior of the COR methodology has been proven in previous works, this contribution focuses on developing the process with a novel kind of metaheuristic algorithm: the ant colony system one. Thanks to...
Level planar embedding in linear time.
Minimal 2-dominating sets in trees
We provide an algorithm for listing all minimal 2-dominating sets of a tree of order n in time 𝒪(1.3248n). This implies that every tree has at most 1.3248n minimal 2-dominating sets. We also show that this bound is tight.
Phenotypic evolution with a mutation based on symmetric α-stable distributions
Multidimensional Symmetric α-Stable (SαS) mutations are applied to phenotypic evolutionary algorithms. Such mutations are characterized by non-spherical symmetry for α<2 and the fact that the most probable distance of mutated points is not in a close neighborhood of the origin, but at a certain distance from it. It is the so-called surrounding effect (Obuchowicz, 2001b; 2003b). For α=2, the SαS mutation reduces to the Gaussian one, and in the case of α=1, the Cauchy mutation is obtained. The...
Quasi-hierarchical evolution algorithm for flow assignment in survivable connection-oriented networks
The main objective of this paper is to develop an effective evolutionary algorithm (EA) for the path-assignment problem in survivable connection-oriented networks. We assume a single-link failure scenario, which is the most common and frequently reported failure event. Since the network flow is modeled as a non-bifurcated multicommodity flow, the discussed optimization problem is NP-complete. Thus, we develop an effective heuristic algorithm based on an evolutionary algorithm. The main novelty of...
Several methods of the reduction of computational complexity.