Search results for "DISTANCE"
showing 10 items of 1009 documents
Phylogeographical structure in the coastal speciesSenecio rodriguezii(Asteraceae), a narrowly distributed endemic Mediterranean plant
2009
Aim Our goals were (1) to assess the levels of chloroplast DNA variation in a narrowly distributed plant restricted to continental islands, (2) to ascertain whether a phylogeographical structure is present in plants restricted to coastal linear systems, and (3) to interpret the results in the light of the known palaeogeography of these islands. Location The Eastern Balearic Islands (Majorca and Minorca) in the Western Mediterranean Basin. Methods Sampling included 134 individuals from 28 populations of Senecio rodriguezii covering the entire range of the species. Sequences of the chloroplast genome (trnT-trnL spacer) were obtained and parameters of population genetic diversity and substruct…
Between-population Similarity in Intestinal Parasite Community Structure of Pike (Esox Lucius)—Effects of Distance and Historical Connections
2009
The effect of geographical distance on similarity in parasite communities of freshwater fish has received considerable attention in recent years, and it has become evident that these apparently simple relationships are influenced by, among other things, colonization ability of parasites and degree of connectivity between the populations. In the present paper, we explored qualitative and quantitative similarity in the intestinal parasite communities of pike (Esox lucius) in a particular system where previously interconnected groups of lakes became isolated ca. 8,400 yr ago. Contrary to our expectations, we did not find differences in similarity between the lake groups or a negative effect of…
Minimal learning machine in hyperspectral imaging classification
2020
A hyperspectral (HS) image is typically a stack of frames, where each frame represents the intensity of a different wavelength of light. Each spatial pixel has a spectrum. In the classification of the HS image, each spectrum is classified pixel-by-pixel. In some of the real-time applications, the amount of the HS image data causes performance challenges. Those issues relate to the platforms (e.g. drones) payload restrictions, the issues of the available energy and to the complexity of the machine learning models. In this study, we introduce the minimal learning machine (MLM) as a computationally cheap training and classification machine learning method for the hyperspectral imaging classificatio…
Individuals in Their Spatial and Social Environments
2016
International audience; This chapter presents the psychological context in which individuals find themselves when they have to choose a place to live (to rent or buy) in a given setting. The act of living in a particular place and type of dwelling arises out of a specific process. It is this decision mechanism that we wish to account for here.
Usefulness of an Internet-based thematic learning network: comparison of effectiveness with traditional teaching.
2006
UniNet is an Internet-based thematic network for a virtual community of users (VCU). It supports one multidisciplinary community of doctoral students, who receive most of the courses on the network. The evident advantages of distance learning by Internet, in terms of costs, comfort, etc., require a previous evaluation of the system, focusing on the learning outcomes of the student. The aim was to evaluate the real learning of the students of doctorate courses, by comparing the effectiveness of distance learning in UniNet with traditional classroom-based teaching. Five doctorate courses were taught simultaneously to two independent groups of students in two ways: one, through the UniNet Netw…
A Non-linear Diffeomorphic Framework for Prostate Multimodal Registration
2011
International audience; This paper presents a novel method for non-rigid registration of prostate multimodal images based on a nonlinear framework. The parametric estimation of the non-linear diffeomorphism between the 2D fixed and moving images has its basis in solving a set of non-linear equations of thin-plate splines. The regularized bending energy of the thin-plate splines along with the localization error of established correspondences is jointly minimized with the fixed and transformed image difference; where, the transformed image is represented by the set of non-linear equations defined over the moving image. The traditional thin-plate splines with established correspondences may p…
Experimental Evaluation of Protein Secondary Structure Predictors
2009
Understanding protein biological function is a key issue in modern biology, which is largely determined by its 3D shape. Protein 3D shape, in its turn, is functionally implied by its amino acid sequence. Since the direct inspection of such 3D structures is rather expensive and time consuming, a number of software techniques have been developed in the last few years that predict a spatial model, either of the secondary or of the tertiary form, for a given target protein starting from its amino acid sequence. This paper offers a comparison of several available automatic secondary structure prediction tools. The comparison is of the experimental kind, where two relevant sets of proteins, a non…
A Dynamic Distributed Algorithm for Multicast Path Setup
2005
In the past few years, there has been a considerable work on multicast route selection techniques, with the aim to design scalable protocols which can guarantee an efficient use of network resources. Steiner tree-based multicast algorithms produce optimal trees, but they are prohibitively expensive. For this reason, heuristic methods are generally employed. Conventional centralized Steiner heuristics provide effective solutions, but they are unpractical for large networks, since they require a complete knowledge of the network topology. In this paper, we propose a new distributed approach that is efficient and suitable for real network adoption. Performance evaluation indicates that it outp…
An efficient distributed approach for dynamic multicast trees
2005
In this paper we present a distributed algorithm for constructing efficient multicast trees in large networks. The algorithm allows the set up of effective distribution trees using a coordination protocol among the network nodes. The algorithm has been implemented and extensively tested both in simulation, and on experimental networks. Performance evaluation indicates that our approach outperforms the state-of-the-art distributed algorithms for multicast tree setup, providing good levels of convergence time and communication complexity. Furthermore, we introduce a distributed technique for dynamically updating the multicast tree. The approach monitors the accumulated damage as nodes join or…
Proximity and distance in spatial economic theory
1997
La proximité entre des éléments d’un ensemble évoque une certaine similitude entre un ou plusieurs de leurs attributs. Elle peut, en général, être évaluée par une distance. L’article revient d’abord sur l’idée de distance, son rôle et les modalités de son expression. Ensuite, il présente diverses représentations formalisées, il expose les contraintes qu’elles imposent dans la représentation de l’espace. Enfin, dans la mesure où la proximité d’un lieu est souvent définie par rapport à un ensemble d’autres sites, on met en évidence le rôle du choix d’une représentation de la distance dans la détermination du lieu qui offre la proximité optimale et l’influence du critère à partir duquel est dé…