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Results n° 1 to 8 of 51 matches
| Title |
Pavel A. Pevzner, "Bio-informatique moléculaire : une approche algorithmique", Traduction de Delphine Hachez, Springer, Coll. Iris, 2006. |
| Author |
GUENOCHE Alain |
| Keywords |
None |
| Topics |
Book review, Algorithms - Algorithmic Theory, Biology, Computer Sciences, Modelling |
| Abstract |
Book review |
| Number |
179, Fall 2007 |
| Language |
 French | Read the article
| Title |
Structuring probabilistic data by Galois lattices |
| Author |
BRITO Paula, POLAILLON Géraldine |
| Keywords |
Conceptual clustering, Galois lattice, Probabilistic data |
| Topics |
Algorithms - Algorithmic Theory, Data Analysis, Lattices, Orders and preorders, Probabilities |
| Abstract |
In this paper we address the problem of organising probabilistic data by Galois concept lattices. Two lattices are proposed, the union lattice and the intersection lattice, corresponding to two distinct semantics, by choosing accordingly the join and meet operators. A new algorithm is proposed to construct the concept lattice. Two real data examples illustrate the presented approach. |
| Number |
169, Spring 2005 |
| Language |
 English | Read the article
Read the article
| Title |
Arch graphs |
| Author |
LECLERC Bruno |
| Keywords |
2-tree, Algorithm, Cycle, Distance, Graph, Tree, Tree encoding |
| Topics |
Algorithms - Algorithmic Theory, Distances, Graphs, Trees |
| Abstract |
An arch-graph may be obtained from a simple edge by successive addings of 3-paths, grafted on their extremities. Equivalently, it admits no subgraph of which every vertex has degree at least three, and is maximal with this property, for a fixed number of vertices. It is known that a tree distance may be summarized by 2n-3 of its entries, conveniently chosen. Arch graphs with n vertices correspond to such sets of entries. They include the graphs of the so-called 2-tree type. We study these graphs, and the k-arch graphs and k-trees which naturally generalize them. It is recalled how a tree metric or function is associated to a valued arch graph, and the properties of this correspondence are investigated. |
| Number |
157, Spring 2002 |
| Language |
French | Read the article
| Title |
Maximizing association by grouping rows or columns of a crosstable |
| Author |
RITSCHARD Gilbert, ZIGHED Djamel, NICOLOYANNIS Nicolas |
| Keywords |
Aggregation, Association, Discretization, Square contingency table |
| Topics |
Algorithms - Algorithmic Theory, Data Analysis, Statistics |
| Abstract |
The strength of association between the row and column variables in a crosstable varies with the level of aggregation of each variable. In many settings such as the simultaneous discretization of two variables, it is useful to determine the aggregation level that maximizes the association. The main association measures with respect to aggregation of rows and columns are studied and permits a heuristic algorithm to (quasi-)maximize the association through aggregation. Simulations carried out to investigate the reliability of the algorithm are presented. |
| Number |
154, Summer 2001, special issue: Implicative statistical analysis |
| Language |
French | Read the article
| Title |
Finding concepts from fuzzy symbolic rooted tree data |
| Author |
GIRARD Régis, RALAMBONDRAINY Henri |
| Keywords |
Concepts, Galois lattice, Nuances, Structured data |
| Topics |
Algorithms - Algorithmic Theory, Classification - Clustering - Partitioning, Lattices, Orders and preorders, Trees |
| Abstract |
n this article, we propose a formalism (ASN) to deal with imprecise and structured data described with attributes and imprecise values. The ASN allow us to represente entities that are composed with parts and sub-parts ; values may be imprecise, unknown and the attributes may be not applicable. We can also take into account constraints that exist between the values of the attributes.
We aim to find concepts from a set of entities described with ASN. Concepts are defined from an extension of the Galois lattice theory to deal with imprecise and structured data. To find concepts, we propose an incremental algorithm that compute a lattice concepts extracted from the Galois lattice where the too general concepts? in regard to a given criteria? are not computed. |
| Number |
147, Fall 1999, special issue: Classification |
| Language |
French | Read the article
| Title |
Cutting seriation for approximate #SAT resolution |
| Author |
LERMAN Israël-César, ROUAT Valérie |
| Keywords |
#P-complete problems, Classification, Complexity theory, Counting, Satisfiability, Seriation |
| Topics |
Algebra, Algorithms - Algorithmic Theory, Classification - Clustering - Partitioning, Logic |
| Abstract |
We propose here a general method for approximating the number of solutions of a boolean formula in conjunctive normal form F. By applying the principle "divise to resolve", this method reduces considerably the computational complexity. It is based on cutting a seriation established on an incidence data table associated with F. Moreover, the independence probability concept is finely exploited. Theoretical justification and intensive experimentation validate the proposed method. |
| Number |
147, Fall 1999, special issue: Classification |
| Language |
French | Read the article
| Title |
A method of nonlinear canonical analysis and its application to biological data |
| Author |
MAKARENKOV Vladimir, LEGENDRE Pierre |
| Keywords |
Multiple linear regression, Polynomial regression, Redundancy analysis |
| Topics |
Algorithms - Algorithmic Theory, Biology, Classification - Clustering - Partitioning, Data Analysis, Linear Algebra, Regression |
| Abstract |
Among the various forms of canonical analysis available in the statistical literature, RDA (redundancy analysis) has become an instrument of choice for ecological analysis. A first data table (Y) contains the response variables (e.g. species data) whereas the second table (X) contains the explanatory variables (e.g. environmental variables). Classical RDA assumes that the relationships between variables in X and Y are linear ; this is unrealistic in most cases. We propose a new ordination method, called polynomial RDA, to do away with the constraints of linearity in these relationships. Polynomial RDA is based on an empirical regression algorithm which allows polynomial relationships to be modelled between the variables in X and Y ; it also takes into account the relationships among the explanatory variables. |
| Number |
147, Fall 1999, special issue: Classification |
| Language |
French | Read the article
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