Search results for " constraints"
showing 10 items of 109 documents
Covariation and phenotypic integration in chemical communication displays: biosynthetic constraints and eco-evolutionary implications
2018
Chemical communication is ubiquitous. The identification of conserved structural elements in visual and acoustic communication is well established, but comparable information on chemical communication displays (CCDs) is lacking. We assessed the phenotypic integration of CCDs in a meta‐analysis to characterize patterns of covariation in CCDs and identified functional or biosynthetically constrained modules. Poorly integrated plant CCDs (i.e. low covariation between scent compounds) support the notion that plants often utilize one or few key compounds to repel antagonists or to attract pollinators and enemies of herbivores. Animal CCDs (mostly insect pheromones) were usually more integrated t…
Phylogeography and Molecular Evolution of Potato virus Y
2012
Potato virus Y (PVY) is an important plant pathogen, whose host range includes economically important crops such as potato, tobacco, tomato, and pepper. PVY presents three main strains (PVYO, PVYN and PVYC) and several recombinant forms. PVY has a worldwide distribution, yet the mechanisms that promote and maintain its population structure and genetic diversity are still unclear. In this study, we used a pool of 77 complete PVY genomes from isolates collected worldwide. After removing the effect of recombination in our data set, we used Bayesian techniques to study the influence of geography and host species in both PVY population structure and dynamics. We have also performed selection and…
Interrogating witnesses for geometric constraint solving
2012
International audience; Classically, geometric constraint solvers use graph-based methods to decompose systems of geometric constraints. These methods have intrinsic limitations, which the witness method overcomes; a witness is a solution of a variant of the system. This paper details the computation of a basis of the vector space of free infinitesimal motions of a typical witness, and explains how to use this basis to interrogate the witness for dependence detection. The paper shows that the witness method detects all kinds of dependences: structural dependences already detectable by graph-based methods, but also non-structural dependences, due to known or unknown geometric theorems, which…
The directed profitable rural postman problem with incompatibility constraints
2017
[EN] In this paper, we study a variant of the directed rural postman problem (RPP) where profits are asso- ciated with arcs to be served, and incompatibility constraints may exist between nodes and profitable arcs leaving them. If convenient, some of the incompatibilities can be removed provided that penalties are paid. The problem looks for a tour starting and ending at the depot that maximizes the difference between collected profits and total cost as sum of traveling costs and paid penalties, while satisfying remaining incompatibilities. The problem finds application in the domain of road transportation service, and in particular in the context of horizontal collaboration among carriers …
Use of contrastive syllabic information in L1-L2map for Spanish pronunciation teaching
2018
En la adquisición del sistema fónico de una segunda lengua (L2) al aprendiz no le basta con familiarizarse con los nuevos sonidos nuevos de la L2, sino que debe interiorizar las pautas distribucionales de los segmentos y las restricciones silábicas propias de la L2. El objetivo de este trabajo es, por un lado, reflexionar sobre los factores lingüísticos y contrastivos que pueden influir en la adquisición de las restricciones silábicas del español como lengua extranjera y, por otro lado, presentar las nuevas funciones de la base de datos multilingüe L1-L2map que permiten, precisamente, realizar análisis contrastivos de la estructura silábica de una lengua nativa (L1) y una L2. A lo largo del…
Data from: Assessing metabolic constraints on the maximum body size of actinopterygians: locomotion energetics of Leedsichthys problematicus (Actinop…
2019
Maximum sizes attained by living actinopterygians are much smaller than those reached by chondrichthyans. Several factors, including the high metabolic requirements of bony fishes, have been proposed as possible body-size constraints but no empirical approaches exist. Remarkably, fossil evidence has rarely been considered despite some extinct actinopterygians reaching sizes comparable to those of the largest living sharks. Here, we have assessed the locomotion energetics of Leedsichthys problematicus, an extinct gigantic suspension-feeder and the largest actinopterygian ever known, shedding light on the metabolic limits of body size in actinopterygians and the possible underlying factors th…
Visual inference of arm movement is constrained by motor representations
2015
International audience; Several studies support the idea that motion inference is strongly motor dependent. In the present study, we address the role of biomechanical constraints in motion prediction and how this implicit knowledge can interfere in a spatial prediction task. Right-handed (RHS) and left-handed subjects (LHS) had to estimate the final position of a horizontal arm movement in which the final part of the trajectory was hidden. Our study highlighted a direction effect: end point prediction accuracy was better to infer the final position of horizontal motion directed toward the median line of human body. This finding suggests that the spatial prediction of end point is mapped ont…
Motivic Pattern Extraction in Symbolic Domain
2008
This chapter offers an overview of computational research in motivic pattern extraction. The central questions underlying the topic, concerning the formalization of the motivic structures, the matching strategies and the filtering of the results, have been addressed in various ways. A detailed analysis of these problems leads to the proposal of a new methodology, which will be developed throughout the study. One main conclusion of this review is that the problems cannot be tackled using purely mathematic or geometric heuristics or classical engineering tools, but require also a detailed understanding of the multiple constraints derived by the underlying cognitive context.
Solving the length constrained K-drones rural postman problem
2021
[EN] In this paper we address the Length Constrained K-Drones Rural Postman Problem (LC K-DRPP). This is a continuous optimization problem where a fleet of homogeneous drones have to jointly service (traverse) a set of (curved or straight) lines of a network. Unlike the vehicles in classical arc routing problems, a drone can enter a line through any of its points, service a portion of that line, exit through another of its points, then travel directly to any point on another line, and so on. Moreover, since the range of the drones is restricted, the length of each route is limited by a maximum distance. Some applications for drone arc routing problems include inspection of pipelines, railwa…
Directionnalité graphique et dominance manuelle : une perspective développementale et interculturelle
2012
In the present work, we try to provide some understanding about the factors underlying the directional tendencies, by examining the impact of biomechanical constraints and cultural habits on directionality in graphic movements. French and Syrian subjects, children and adults, were compared in six experiments in order, to put in evidence the cognitive and psychomotor differences caused by the fact that the Eastern and Western cultures oppose on the directionality of writing and reading habits, and that the two hands are opposite in the directionality by adopting movements determined by biomechanical constraints. Likewise, this comparison allowed us to determine the relative strength of these…