Search results for "LESS"
showing 10 items of 2452 documents
Streaming for vehicular users via elastic proxy buffer management
2004
In this article we refer to the market of vehicular networks, where groups of customers located in the same public vehicle (e.g., a train or bus) connect to a terrestrial network through a wireless/satellite backbone link. Elastic buffering is a proxy management technique devised to decouple the multimedia information retrieval rate on the network backbone from the playout streaming rate at the user terminal. It has been shown in the past that the application of elastic buffering mechanisms in terrestrial networks brings significant advantages in terms of network effectiveness. We show that elastic buffering is an extremely effective means to reduce, or even eliminate, streaming service out…
Level-Crossing Rate and Average Duration of Fades of the Envelope of Mobile-to-Mobile Fading Channels in Cooperative Networks Under Line-of-Sight Con…
2008
This paper studies the fading behavior of mobile- to-mobile (M2M) fading channels in relay-based cooperative networks under line-of-sight (LOS) conditions. Here, we assume that LOS components exist in both the direct link between the source mobile station (SMS) and the destination mobile station (DMS) as well as in the link via the mobile relay (MR). In such a propagation environment, the fading channel is referred to as the multiple-LOS second-order scattering (MLSS) channel. The fading behavior of MLSS channels is studied by analyzing the level-crossing rate (LCR) and the average duration of fades (ADF) of the received envelope. We have derived analytical expressions for the LCR, ADF, and…
Mobile radio channel models for present and future wireless communication systems
2008
From the beginnings of mobile communication, there is a high demand for realistic models for mobile fading channels. The reason for the demand is that channel models are essential for the performance evaluation, parameter optimisation, and test of mobile communication systems. Design methods for mobile fading channels are therefore of great importance for system engineers who are involved in the development of present and future mobile communication systems. In this presentation, an overview will be given about several design methodologies commonly used for the design of mobile radio channel models in present and future wireless communication systems. All presented channel models have in co…
Modeling of mobility and groups in inter-vehicular MANET-based networks
2007
This paper evaluates the behavior of mobile ad hoc networks when group mobility is involved. We concentrate on group mobility because road vehicles tend to form groups or fleets whose behavior depends on the behavior of the close-by vehicles. We propose four different group mobility models and present a mobility pattern generator, called grcmob that we designed to be used with the ns-2 simulator. We evaluate the performance of vehicular ad hoc networks under a wide number of scenarios using both TCP and UDP data traffic. We show that the number of groups is more important than the number of nodes and that the impact of area size is almost negligible. We also reveal that the mixture of inter…
Group mobility impact over TCP and CBR traffic in mobile ad hoc networks
2004
We present an analysis of the effect that mobility models have over the performance of a mobile ad hoc network. We concentrate on group mobility because there is a growing attention on the development and evaluation of MANET's approach applied to personal area networks (PANs), especially based on Bluetooth technology. We investigate the effect that the mobility model has on the performance of CBR traffic and TCP traffic. We propose four different group mobility models and describe a mobility pattern generator called grcmob to be used with the ns-2 simulator. We perform a thorough evaluation of a MANET behavior using as a reference the behavior obtained with the random waypoint mobility mode…
Network Connectivity and Area Coverage for UAV Fleet Mobility Model with Energy Constraint
2016
International audience; Our main focus through the present paper is on developing an original distributed mobility model for autonomous fleet of interconnected UAVs (Unmanned Aerial Vehicles) performing an area exploration mission. The UAVs, equipped with wireless ad-hoc capabilities, are required to optimally explore an area while maintaining connectivity with their neighboring UAVs and the base station. Because energy is a scarce resource, especially for UAVs, its wise management is quite beneficial for the network lifetime and mission success. Hence, the proposed mobility model, compared to other models in the literature, is the first to ever include the remaining energy level as decisio…
LynxNet: Wild Animal Monitoring Using Sensor Networks
2010
Monitoring wild animals, especially those that are becoming endangered (for example, lynxes and wolves) is important for biology researchers. Solutions for the monitoring already exist; however, they all have drawbacks, such as limited range or lifetime, sensing modality, reporting delays, unreliability of operation. In this work we describe our experiences in designing an improved animal monitoring sensor system and low-level software for sensor node control and communication. The target animals for this particular research are wild lynxes or canines, however it can be extended to other animal species. The LynxNet system is based on tracking collars, built around TMote Mini sensor nodes, s…
Role of Molybdenum on the Electronic Properties of Passive Films on Stainless Steels
2020
Potentiostatic polarization of different stainless steel grades with a mirror surface finishing was performed in order to investigate the role of Mo on stainless steels corrosion behaviour. In the attempt to gain more insight into transpassive dissolution mechanism, passive films were grown in neutral aqueous solution (pH ∼ 7) at different polarizing potentials ranging from passive to transpassive conditions. According to the photoelectrochemical characterization, Cr dissolution occurs even at low polarizing potentials in the case of AISI 304L, while higher band gap values were obtained for passive films grown on austenitic 316L and duplex SSs. Capacitance measurements suggest that the flat…
Primeros hallazgos del molusco marino invasor Pinctada radiata (Leach, 1840) (Bivalvia: F. Margaritidae) en la costa valenciana (España)
2021
Se dan a conocer por primera vez diversos hallazgos del molusco bivalvo marino lessepsiano Pinctada radiata en la costa valenciana, concretamente en la costa del Golfo de Valencia (España). Esta especie puede causar efectos negativos sobre el ecosistema, afectando a su biodiversidad autóctona. Se proporcionan datos conquiológicos de la concha y el mapa de distribución geográfica actual de esta especie en la costa valenciana y en el mediterráneo occidental. -- First findings of invasive marine mollusc Pinctada radiata (Leach, 1840) (Bivalvia: F. Margaritidae) on the Valencian coast (Spain). Several findings of the marine Lessepsian bivalve mollusc Pinctada radiata are disclosed for the first…
Introduzione a Capitali senza re nella Monarchia spagnola
2020
Prefazione al volume Capitali senza re nella Monarchia spagnola. Preface to volume Capitali senza re nella Monarchia spagnola