Search results for " Distance"
showing 10 items of 696 documents
A new way of achieving multi-path routing in wireless networks
2020
In the 21st century, the wireless technology is still developing rapidly and trying to be 'Faster, Higher, and Stronger': faster data rate, higher bandwidth and stronger connectivity. Wireless Mesh Networks (WMN) have been envisioned as an important solution to the next generation wireless networking which can be used in wireless community networks, wireless enterprise networks, transportation systems, home networking and last-mile wireless internet access. They also provide a cheap, quick and effective way for building wireless data networks. Considering the nature of these networks, routing is a key process for operating the WMN. This paper proposes a new way of creating multi-path routin…
Une nouvelle approche de la réussite dans les MOOC : confronter les usages aux comportements réels pour adapter/repenser les indicateurs de l'évaluat…
2019
International audience; L'évaluation dans les MOOC a été réalisée de manière privilégiée à l'aide des learnings analytics, autant de traces numériques enregistrant l'ensemble des actions réalisées par un inscrit dans le dispositif. L'exploitation de ces données a révélé l'existence d'un très fort taux d'abandon parmi les cohortes d'inscrits au sein de MOOC. Ce faisant, ce sont deux principales approches de l'évaluation de la réussite qui ont été adoptées : celle de la persistance et celle, transposée de la formation formelle, de la validation par l'obtention d'une certification. Néanmoins, celles - ci ne permettent pas de tenir compte de la diversité des intentions des inscrits. A l'aide de…
Forests as dispersal barriers for Erebia medusa (Nymphalidae, Lepidoptera)
2000
Summary The nymphalid butterfly Erebia medusa is a typical species of meadows that are poor in nitrogen and fallow land. In forests, it is only found on clearings with meadow-like structures. However, it is missing on wind exposed places, too. 239 imagoes of E. medusa were sampled in the Aggtelek Karst region (north-eastern Hungary) at six different localities at the end of May 1997. The sample sizes varied between 33 and 46. The studied karst area has a typical forest steppe vegetation and is characterised by a mosaic-like distribution of meadows and forests. The sampled butterflies were analysed by allozyme electrophoresis. The level of polymorphism was significantly higher in the samples…
Enseigner l’EPS à distance. Des compétences nouvelles pour des savoirs secondaires
2021
International audience
Strategies to exiting the COVID-19 lockdown for workplace and school: A scoping review
2021
Highlights • Epidemiological conditions should be monitored and enforced. • COVID-19 must be under control below thresholds of safeguards. • Testing, contact tracing, and isolation strategies are essential components to ease the lockdown. • The maintenance of social distancing measures is an overarching mitigation strategy. • The benefit gained from the implementation of social distancing was evident.
L∞ estimates in optimal mass transportation
2016
We show that in any complete metric space the probability measures μ with compact and connected support are the ones having the property that the optimal transportation distance to any other probability measure ν living on the support of μ is bounded below by a positive function of the L∞ transportation distance between μ and ν. The function giving the lower bound depends only on the lower bound of the μ-measures of balls centered at the support of μ and on the cost function used in the optimal transport. We obtain an essentially sharp form of this function. In the case of strictly convex cost functions we show that a similar estimate holds on the level of optimal transport plans if and onl…
A Scatter Search Algorithm for the Split Delivery Vehicle Routing Problem
2008
In this chapter we present a metaheuristic procedure constructed for the special case of the Vehicle Routing Problem in which the demands of clients can be split, i.e., any client can be serviced by more than one vehicle. The proposed algorithm, based on the scatter search methodology, produces a feasible solution using the minimum number of vehicles. The quality of the obtained results is comparable to the best results known up to date on a set of instances previously published in the literature.
A New Metaheuristic for the Vehicle Routing Problem with Split Demands
2007
In this paper we present a metaheuristic procedure constructed for the special case of the Vehicle Routing Problem in which the demands of the clients can be split, i.e., any client can be serviced by more than one vehicle. The proposed algorithm, based on the scatter search methodology, produces a feasible solution using the minimum number of vehicles. The results obtained compare with the best results known up to date on a set of instances previously published in the literature.
Efficient Local Search Limitation Strategies for Vehicle Routing Problems
2008
In this paper we examine five different strategies for limiting the local search neighborhoods in the context of vehicle routing problems. The vehicle routing problem deals with the assignment of a set of transportation orders to a fleet of vehicles, and the sequencing of stops for each vehicle to minimize transportation costs. The examined strategies are applied to three standard neighborhoods and implemented in a recently suggested powerful memetic algorithm. Experimental results on 26 well-known benchmark problems indicate significant speedups of almost 80% without worsening the solution quality. On the contrary, in 12 cases new best solutions were obtained.
The effect of distance between parasitoid and host on the parasitism of Psyttalia concolor (Szépligeti) in organic olive orchards
2013
Bactrocera oleae (Rossi) is a major pest of olive fruits. Biological control of olive fruit fly mainly relies on the activity of the Braconid species Psyttalia concolor (Szépligeti), which parasitizes Bactrocera oleae at the larval stage. Parasitism tests have been carried out at the insect growing facility (insectariums) of the Mediterranean Agronomic Institute of Bari (C.I.H.E.A.M.). The critical point of the use of P. concolor as a biological control agent in organic olive crop is the assessment of its effectiveness against B. oleae. Its lower presence in fruits of cultivated olives rather than in small fruits of wild olives suggests an influence of the size of the fruit, and of the thic…