Search results for "Multia"

Vers la conception d'une action de réponse pour la gestion de catastrophe, utilisant la modélisation de connaissances

2018

International audience; Ce travail de positionnement souligne les problèmes actuels liés aux diffé-rents aspects de la collaboration inter agence pendant la réponse à une catastrophe. La coordination et la coopération dépendent de l'usage et du partage d'informations, qui doivent faire face aux problèmes d'interopérabilité, de droits d'accès et de qualité. Le projet de recherche a pour but de fournir une évaluation de l'impact de l'information sur la réponse à une catastrophe afin d'aider la prise de décision concernant l'usage et le partage de l'information en répondant à des questions telles que: quelles informa-tions devraient être partagées ou quelle qualité de données utilisées pour am…

Naimisen normit, käytännöt ja konfliktit : esiaviollinen ja aviollinen seksuaalisuus 1800-luvun lopun keskisuomalaisella maaseudulla

2010

Anomaly‐based intrusion detection systems: The requirements, methods, measurements, and datasets

2021

International audience; With the Internet's unprecedented growth and nations' reliance on computer networks, new cyber‐attacks are created every day as means for achieving financial gain, imposing political agendas, and developing cyberwarfare arsenals. Network security is thus acquiring increasing attention among researchers, practitioners, network architects, policy makers, and others. To defend organizations' networks from existing, foreseen, and future threats, intrusion detection systems (IDSs) are becoming a must. Existing surveys on anomaly‐based IDS (AIDS) focus on specific components such as detection mechanisms and lack many others. In contrast to existing surveys, this article co…

Energy Efficient Optimization for Solar-Powered UAV Communications System

2021

In this work, we explore the energy efficiency optimization for a solar-powered unmanned aerial vehicle (UAV) communications system. We consider a scenario where a number of ground users (GUs) connect with a solar-powered multi-antenna UAV over a wireless link. First, we are able to derive the relations between the uplink data rate and heading angle of UAV and transmission power of GUs. In addition, the harvested energy from solar light is also affected by UAV’s angle. Accordingly, with the objective to maximize the energy efficiency that is related to uplink data rate and energy consumption, we propose to dynamically adjust the UAV trajectory and gesture, by optimizing its velocity, accele…

Synthesis and characterization of well-defined poly(tert-butyl acrylate) star polymers

2009

Abstract Star polymers with different numbers and lengths of poly(tert-butyl acrylate) (PTBA) arms were obtained via atom transfer radical polymerization. Aliphatic alcohols with different number of hydroxyl groups varying from 3 to 6 and calix[4]arenes based on pyrogallol with 12 and 16 phenol groups were transformed to bromoester derivatives to prepare multifunctional ATRP initiators used as the cores of the stars. The star polymers were characterized by GPC with refractive index, multiangle laser light scattering and viscosimetric detectors. The molar masses of the stars reached 70,000 g/mol and the molar mass dispersities did not exceed 1.2. To elucidate the compact structure of the sta…

Photodegradation of polyglycidol in aqueous solutions exposed to UV irradiation

2011

The photodegradation of polyglycidol in aqueous solution with UV wavelength of 254 nm was investigated. The experiments were carried out in air at a constant temperature and the photodegradation of polyglycidol (PGl) was compared to that of poly(ethylene oxide) (PEO), the most widely studied polyether. Size exclusion chromatography with multiangle light scattering detection (SEC-MALLS) was used to measure the changes in the molar masses and molar mass dispersities of polymers during degradation. The molar mass of PGl decreased dramatically during the first period of UV irradiation and then gradually approached a limiting value of 17,000 g/mol, regardless of the initial polymer concentration…

Star poly(2-ethyl-2-oxazoline)s-synthesis and thermosensitivity

2011

A series of star-shaped poly(2-ethyl-2-oxazoline)s was prepared by cationic polymerization. The polymerization was initiated by dipentaerythrityl hexakis(4-nitrobenzene sulfonate) and a tosylated hyperbranched polymer of glycidol. The polymerization proceeded in a controlled manner. The star structure of the products was determined by nuclear magnetic resonance. The molar mass distributions that were measured by gel permeation chromatography with multiangle laser light scattering were narrow, and the experimental values of the molar masses were close to those predicted. The very compact structure of the polymers obtained (compared with the linear counterparts) confirmed the star formation. …

CONSIDERAZIONI TEORICHE E PRATICHE SUL METODO DEL MASSIMO RETTANGOLO CIRCOSCRITTO PER LA VALUTAZIONE DELL’AMPIEZZA DELLA TENSIONE TANGENZIALE NEI CRI…

2012

The multiaxial fatigue criteria based on the approach of the critical plane require the determination of the amplitude of the alternating shear stress τ aacting on different planes passing through the point of the material analyzed. In the case of non-proportional stresses the shear stress vector varies both in modulus and direction and its tip describes a curvedefined loading path. In these cases τ ais identified and evaluated by means of special procedures the most recent, and apparently more effective, of which is that of the Maximum Circumscribed Rectangle (MCR) to the loading path itself. In particular τ ais equal to the length of the diagonal of the MCR. In this paper, the MCR method …

Improvements in the algorithms for the determination of the shear stress components in critical plane class fatigue criteria

2010

This paper presents two improvements in the procedure for the evaluation of the amplitude and mean values of the shear stress in critical plane class fatigue criteria, when the method of the Minimum Circumscribed Circle (MCC) to the path of the tip of the  vector is used. In particular, the paper shows how it is possible to reduce the number of material planes passing through the point of interest in which the MCC has to be determined and the number of points of each curve that has to be considered for the determination of the MCC, noticeably reducing the computational time.

Decentralized classification in societies of autonomous and heterogenous robots

2011

This paper addresses the classification problem for a set of autonomous robots that interact with each other. The objective is to classify agents that “behave” in “different way”, due to their own physical dynamics or to the interaction protocol they are obeying to, as belonging to different “species”. This paper describes a technique that allows a decentralized classification system to be built in a systematic way, once the hybrid models describing the behavior of the different species are given. This technique is based on a decentralized identification mechanism, by which every agent classifies its neighbors using only local information. By endowing every agent with such a local classifie…