Search results for "Tribute"
showing 10 items of 1455 documents
Link scheduling in sensor networks for asymmetric average consensus
2012
Wireless Sensor Networks constitute a recent technology where the nodes cooperate to obtain, in a totally distributed way, certain function of the sensed data. One example is the average consensus algorithm, which allows every node to converge to the global average. However, this algorithm presents two major drawbacks in practice. The first one is that instantaneous symmetric links are required, which are hard to ensure in practice because of the presence of wireless interferences. The second one is that all the nodes are required to communicate with all of their local neighbors in every iteration, which can lead to an unbounded delay. In order to solve these issues, we propose a novel link…
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…
A methodology for evaluation of operational zones for distributed generation based on DFIG
2017
This study developed a methodology to determine zones of acceptable voltage profiles for wind power generation connected to distribution systems. Three load profiles (residential, commercial and industrial) connected to the distribution network were analyzed considering the impact on voltage levels and steady-state stability for different wind speeds and wind generator control strategies. The wind generator model is based on doubly fed induction generator (DFIG) and were developed using Matlab/Simulink. The presented methodology can be used to map the impact on operation of different types of control, the time of day and the available wind speed and it is not limited only for DFIG. The resu…
Italian red wine in the Japanese market: a hedonic price analysis
2017
This study applies the hedonic pricing model to examine important objective attributes appearing on the label of Italian wines influencing average customer wine prices in Japan. Data on 829 red Italian wines sold in the Japanese market were collected through the wine searcher dataset, and the information included on the wine labels, useful for assisting in the selection and appreciation of wines, has been included. A log-linear model was esteemed and the proposed hedonic equation accounted for 43.5% of the variation in wine prices. The results indicate that international grape varieties, alcohol content and the year of production explain most of the price difference. On the other hand, the …
The premium price for Italian red wines in new world wine consuming countries: the case of the Russian market
2017
Italian wine is increasingly appreciated in new world consumer countries and, in particular, in Russia where consumers associate its consumption with an Italian lifestyle. In this paper, market value for wine search attributes is measured through the estimation of a hedonic price model using online data from a Wine Searcher website and the information contained in the labels of wines marketed in Russia. Results show a premium price for wines from Piedmont and Tuscany, and in particular for non-native varieties and for Indicazione Geografica Tipica and Protected Geographical Indication wines. Additionally, vintage and higher alcohol content have a significant positive impact on the prices th…
Factors affecting consumer preferences for “natural wine”: An exploratory study in the Italian market
2020
PurposeThe aim of this study is to understand which wine quality characteristics, consumers' attitudes and socio-demographic characteristics affect the consumers' willingness to pay (WTP) a premium price for a bottle of natural wine.Design/methodology/approachThe research is experimental and investigated the purchasing intentions of 613 Italian wine consumers within a hypothetical setting. In order to elicit WTP for natural wine, a multiple price list (MPL) in a comparison with one bottle of conventional wine, with an average price of €5 was adopted. To understand which quality attributes of wine affect the consumers' WTP for natural wine, a Tobit regression model was implemented.FindingsTh…
Network Reconfiguration Suitability for Scientific Applications
2008
This paper analyzes the communication pattern of several scientific applications and how they can make profit of network reconfiguration in order to adapt network topology to the communication needs so that total execution time is reduced. By using an analysis methodology based on real application executions, we study the variation of the required communication bandwidth with time and also the global interprocedural communication patterns. Results show that required bandwidth between each pair of processes does not significantly fluctuates, leading to a constant use of the links and therefore discouraging dynamic reconfigurations of the network during execution time. Nevertheless, the group…
Measurement and Modeling of the Origins of Starvation of Congestion-Controlled Flows in Wireless Mesh Networks
2009
Significant progress has been made in understanding the behavior of TCP and congestion-controlled traffic over CSMA-based multihop wireless networks. Despite these advances, however, no prior work identified severe throughput imbalances in the basic scenario of mesh networks, in which a one-hop flow contends with a two-hop flow for gateway access. In this paper, we demonstrate via real network measurements, testbed experiments, and an analytical model that starvation exists in such a scenario; i.e., the one-hop flow receives most of the bandwidth, while the two-hop flow starves. Our analytical model yields a solution consisting of a simple contention window policy that can be implemented vi…
Supporting a Pseudo-TDMA Access Scheme in Mesh Wireless Networks
2013
Wireless mesh networks appear a promising solution for pro- viding ubiquitous low-cost wireless access, but cannot rely on simple CSMA access protocols because of the critical inefficiencies that arise in topologies with hidden nodes. To overcome these limitations, some important protocol extensions based on synchronization and reservation mechanisms have been ratified. In this paper we show that an alternative approach to the standardiza- tion of new features and signaling messages for mesh networks can be the utilization of programmable nodes able to execute different MAC protocols programmed on the fly. Signaling messages are used only for disseminating the new protocol among the nodes. …
An automatic cooperative retransmission MAC protocol in Wireless Local Area Networks
2009
Existing solutions for cooperation in wireless networks either require simultaneous transmission of source and relay nodes or impose major modifications to original MAC protocols. In this paper, a new efficient retransmission MAC protocol is proposed for IEEE 802.11 based cooperation communications, with minimum modifications to the DCF scheme. Throughput and access delay performance of the proposed protocols is analyzed in error-prone and highly temporally correlated channels. Numerical results show that significant benefits can be achieved with our cooperative protocol, compared with the legacy schemes.