Search results for " Network"

Using self-deferral to achieve fairness between Wi-Fi and NR-U in downlink and uplink scenarios

2022

Wireless networks operating in unlicensed bands generally use one of two channel access paradigms: random access (e.g., Wi-Fi) or scheduled access (e.g., LTE License Assisted Access, LTE LAA and New Radio-Unlicensed, NR-U). The coexistence between these two paradigms is based on listen before talk (LBT), which was, however, designed for random access. Meanwhile, scheduled systems require that their transmissions start at the beginning of a slot boundary. Synchronizing this boundary to the end of LBT usually requires transmitting a reservation signal (RS) to block the channel. Since the RS is a waste of channel resources, we investigate an alternative self-deferral approach (gap-based access…

Achieving Fair Bandwidth Distribution in WiFi Networks: A Game Theoretical Approach

2011

International audience; Achieving fair bandwidth distribution among uplink and downlink ows in IEEE 802.11 infrastructure networks is a complex issue, due to the well-known features of the Distributed Coordination Function (DCF) which regulates the access to the shared medium. Indeed, the dynamic adaptation of the contention windows causes phenomena of short-term unfairness, while the use of homogeneous contention parameters among the contending nodes makes the aggregated downlink bandwidth equal to the uplink bandwidth of a single node. We propose a dynamic tuning of the contention parameters used by the nodes, based on simple network monitoring functionalities and rational strategies. Spe…

Analysis and modeling of wind directions time series

2013

This work aims at studying some aspects of wind directions in Italy and supplying appropriate models. A comparison is presented between independent mixture and Hidden Markov models, which seem to be appropriate as far as the series we studied.

Wind speed spatial estimation for energy planning in Sicily: introduction and statistical analysis

2008

Abstract The exploitation of the renewable energy sources plays a key role for achieving the CO 2 emissions reduction targets established by the Kyoto Protocol, as well as for facing the shortage of world fossil fuels reserves. In countries like Italy, with an high potential in terms of wind power generation, an efficient energy planning based on renewables is a very complex task. It encompasses many aspects: the resource availability assessment, the compliance with environmental and legislative constraints and last, but not least, the technical aspects linked to the safe integration to the grid of the intermittent power generated by the wind farms. This paper is the first part of a study a…

An Ontology-Based Monitoring System in Vineyards of the Burgundy Region

2019

Given the France's rich wine heritage as well as its pioneering position as the world's second wine producer, the production of high quality wines plays a role of primary importance. The recent development of IOT and efficient big data processing has been shown to provide purposeful issue to permanent monitoring during the entire wine making process. Standing within this trend, we introduce in this paper an intelligent system for vineyards monitoring in the Burgundy region. The main trust of the proposed system relies on the use of the Swrl rules in WineCloud ontology. The design of the ontology is mainly based on information gathered from interviews with wine growers. In addition, sensor d…

Mapping the scientific research on wine and health (2001-2011)

2013

[EN] There have been a substantial number of studies suggesting possible health benefits from polyphenols in wine, especially red wine. These hypothetical effects, in addition to those of alcohol, are attributed by many to antioxidant and antiinflammatory effects of the polyphenols. The aim of this paper was to map the scientific research on wine and health by using bibliographic analyses of papers published during the period 2002−2011. Papers were published in 535 different journals and in 106 different subject categories, the most productive journals being the Journal of Agricultural and Food Chemistry, Food Chemistry and Molecular Nutrition, and Food Research, and the most productive sub…

Monitoring High-Quality Wine Production using Wireless Sensor Networks

2009

This work reports the experience on the design and deployment of a WSN-based system for monitoring the productive cycle of high-quality wine in a Sicilian winery. Besides providing the means for pervasive monitoring of the cultivated area, the project described here is aimed to support the producer in ensuring the overall quality of their production, in terms of accurate planning of interventions in the field, and preservation of the stored product. Wireless Sensor Networks are employed as the sensing infrastructure of a distributed system for the control of a prototypal productive chain; nodes have been deployed both in the field and in the cellar, where wine aging is performed, and data i…

Towards a Dual-mode Adaptive MAC Protocol (DMA-MAC) for Feedback-based Networked Control Systems

2014

Abstract Automated control systems play an important part in many industrial domains and the medium used for communication between devices in these systems is in transition from wired to wireless for cost reasons. Control systems have strict requirements on delay, throughput, and reliability, that vary with time during operation. Addressing these requirements requires predictable and robust protocols to be employed, and they must be adaptive to the varying states of the controlled process. In this article, we propose a dual-mode adaptive medium access control protocol that caters for two main operation modes in control systems: the steady mode operation, and the transient mode operation. We…

Adaptive Collision Avoidance through Implicit Acknowledgments in Wireless Sensor Networks

2008

Simultaneous ranging and self-positioning in unsynchronized wireless acoustic sensor networks

2016

Automatic ranging and self-positioning is a very desirable property in wireless acoustic sensor networks, where nodes have at least one microphone and one loudspeaker. However, due to environmental noise, interference, and multipath effects, audio-based ranging is a challenging task. This paper presents a fast ranging and positioning strategy that makes use of the correlation properties of pseudonoise sequences for estimating simultaneously relative time-of-arrivals from multiple acoustic nodes. To this end, a proper test signal design adapted to the acoustic node transducers is proposed. In addition, a novel self-interference reduction method and a peak matching algorithm are introduced, a…