4,205 research outputs found
Modelling and trading the Greek stock market with gene expression and genetic programing algorithms
This paper presents an application of the gene expression programming (GEP) and integrated genetic programming (GP) algorithms to the modelling of ASE 20 Greek index. GEP and GP are robust evolutionary algorithms that evolve computer programs in the form of mathematical expressions, decision trees or logical expressions. The results indicate that GEP and GP produce significant trading performance when applied to ASE 20 and outperform the well-known existing methods. The trading performance of the derived models is further enhanced by applying a leverage filter
Improved Bounds for Drawing Trees on Fixed Points with L-shaped Edges
Let be an -node tree of maximum degree 4, and let be a set of
points in the plane with no two points on the same horizontal or vertical line.
It is an open question whether always has a planar drawing on such that
each edge is drawn as an orthogonal path with one bend (an "L-shaped" edge). By
giving new methods for drawing trees, we improve the bounds on the size of the
point set for which such drawings are possible to: for
maximum degree 4 trees; for maximum degree 3 (binary) trees; and
for perfect binary trees.
Drawing ordered trees with L-shaped edges is harder---we give an example that
cannot be done and a bound of points for L-shaped drawings of
ordered caterpillars, which contrasts with the known linear bound for unordered
caterpillars.Comment: Appears in the Proceedings of the 25th International Symposium on
Graph Drawing and Network Visualization (GD 2017
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Algorithms for network piecewise-linear programs
In this paper a subarea of Piecewise-Linear Programming named network Piecewise-Linear Programming (NPLP) is discussed. Initially the problem formulation, main efinitins and related Concepts are presented. In the sequence of the paper, four specialized algorithms for NPLP, as well as the results of a preliminary computational study, are presented
Locating a Tree in a Phylogenetic Network in Quadratic Time
International audienceA fundamental problem in the study of phylogenetic networks is to determine whether or not a given phylogenetic network contains a given phylogenetic tree. We develop a quadratic-time algorithm for this problem for binary nearly-stable phylogenetic networks. We also show that the number of reticulations in a reticulation visible or nearly stable phylogenetic network is bounded from above by a function linear in the number of taxa
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