Search results for " Automobile"
showing 10 items of 138 documents
Testbed implementation of the meta-MAC protocol
2016
The meta-MAC protocol is a systematic and automatic method to dynamically combine any set of existing MAC protocols into a single higher layer MAC protocol. We present a proof-of-concept implementation of the meta-MAC protocol by utilizing a programmable wireless MAC processor (WMP) on top of a commodity wireless card in combination with a host-level software module. The implementation allows us to combine, with certain constraints, a number of protocols each represented as an extended finite state machine. To illustrate the combination principle, we combine protocols of the same type but with varying parameters in a wireless mesh network. Specifically, we combine TDMA protocols with all po…
Significance of channel failures on network performance in CRNs with reserved spectrum
2016
It is well understood that in wireless networks, channel failures, which are typically caused by equipment or power failures as well as intrinsic features in radio transmissions, such as fading and shadowing, can easily result in network performance degradation. Therefore, fast recovery from channel failures is an important measure that should be incorporated with those networks. Consequently, in a cognitive radio network (CRN), channel failures can cause significant performance degradation in both primary and secondary networks. Instead, retainability, i.e., the capability of providing continuous connection for users must be guaranteed even if a significant network element is disrupted. In…
An Impulse Response Model for the 60 Ghz Channel Based on Spectral Techniques of alpha-stable Processes
2007
International audience; In order to make realistic simulations of the radio propagation mechanism in ultra-wide band channels, an appropriate model is needed. In this paper we propose a new technique to model the impulse response of the 60 Ghz channel. This new approach is based on the spectral analysis of alpha-stable processes. Our new model presents many advantages: firstly, the channel is characterized only by a one deterministic function (spectral density) in the place of four parameters. Secondly, the estimations procedure deals directly with the measured transfer functions which avoids loosing information in data pretreatment. Finally, an estimation of the spectral measure permits to…
Le comportement des résidents dans leur stationnement automobile
2000
International audience
Configuration des trajets domicile travail des ménages biactifs
2020
La présence de deux actifs occupés dans un ménage représente depuis le dernier quart du XXème siècle la norme dominante pour les familles : une situation censée assurer un certain bien être et les bonnes conditions de reproduction de la société. Les biactifs comptent pour un tiers des ménages en 2015, ils représentent la moitié des individus et du parc automobile des ménages. Or les différentes études menées dans ce rapport sur la configuration spatiale des trajets domicile-travail révèlent une hétérogénéité profonde en ce qui concerne les contraintes de coût et de temps passé en transport. La configuration spatiale formée par le lieu de résidence et les deux lieux d'emplois est assimi…
Target 5G visible light positioning signal subcarrier extraction method using particle swarm optimization algorithm
2021
International audience; With the explosive growth of demand for Internet of Things (IoT) applications and the increasing dependence of users on wireless connections, indoor location based service(LBS) under 5G-Public-Private Partnership (5G-PPP) using cases have received more attention and get rapid development. Thanks to the safty, security and customization of 5G network pointed by 5G forum white paper, indoor positioning systems using unified 5G New Radio (NR) signals have become the focus of the next generation of visible light positioning (VLP) systems. In 5G New Radio(NR) frame, totally 192 subcarriers are used to carry positioning reference signal(PRS). In order to improve the positi…
Alliance portfolio diversity, organizational slack, and firm performance
2013
In this paper we analyze whether and how the availability of internal resources in the form of slack influences a firm ability to deal with partner diversity in its alliance portfolio. Alliances with diverse partners provide access to a broader pool of complementary resources, but they also entail significant coordination costs. In this context, we argue that slack acts as a doubleedged sword that can either facilitate or hinder the management of interdependencies among different alliance projects. Accordingly, we further argue that the net impact of slack will depend on the firm’s experience in dealing with the challenges posed by portfolio diversity. Empirical analysis on a sample of firm…
Presse de gauche, autodromes et courses de vitesse. L'Humanité et Le Populaire aux prises avec l'essor des sports automobiles (1920-1939)
2022
IV. Sous le signe de la détente ? Popularisation des autodromes et des sports mécaniques (1934-1939) V. Conclusion, perspectives Résumé : La presse socialiste et communiste est mobilisée ici comme première entrée pour la définition d'un discours « de gauche » sur les autodromes et les courses automobiles. Les archives du Populaire et de L'Humanité sont interrogées et comparées pour la période 1920-1939, à travers des méthodologies visant à croiser les discours « ordinaires » sur ces objets et ceux qui se déploient à l'occasion de « grands événements » (Grand prix de l'Automobile Club de France, 24 heures du Mans). Au fil du temps, et d'un quotidien à l'autre, l'attention accordée au sport a…
Fast 3D Ray Tracing for Indoor Coverage Solutions
2016
Optimal wireless indoor network planning requires huge number of iterations and evaluations of indoor coverage for each antenna location until an optimal solution is reached. Consequently, accurate and scalable calculation of power strength for indoor scenarios becomes necessary. The contribution in this paper is to reduce the complexity of 3D ray tracing for deterministic indoor power prediction. In order to achieve that while preserving the accuracy, image theory with feasible reflection volume as preprocessing approach is introduced. This proposed algorithm stores the image, its feasible reflection volume and valid area of receiving points. Significant complexity reduction is achieved by…
Channel Occupancy-Based Dynamic Spectrum Leasing in Multichannel CRNs: Strategies and Performance Evaluation
2016
Spectrum leasing has been proposed as an effective approach for enabling more flexible spectrum utilization in CRNs. In CRNs, a primary network (PN) which consists of multiple primary users (PUs) can lease part of the licensed spectrum to secondary users (SUs) in exchange for operational benefits. The focus of this study is to investigate how and to what extent the PN allows spectrum leasing in CRNs, considering the QoS requirements of the PN and the secondary network (SN). Correspondingly, we propose two dynamic spectrum leasing strategies, which can improve the QoS performance of SUs while ensuring sufficient remuneration for PUs. In order to dynamically adjust the portion of leased bandw…