Search results for " sensor"

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…

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…

Influence of Soil Salinity on Sensory Characteristics and Volatile Aroma Compounds of Nero d’Avola Wine

2010

The influence of soil salinity on the chemical composition, volatile aromatic compounds, and sensory characteristics of Nero d'Avola wine was examined. Data on vineyard productivity, such as grape yield, are also reported. Physicochemical parameters were determined on the samples analyzed. Solid-phase microextraction was used for the extraction of aromatic volatile compounds, followed by capillary gas chromatography-mass spectrometry. Sensory analyses were performed by visual inspection, smelling, and tasting. Statistical analysis showed that most of the physicochemical parameters and volatile constituents, both primary and fermentation aromas, were influenced by the soil salinity. The comp…

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…

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. …

Narrow Band Solid-Liquid Composite Arrangements: Alternative Solutions for Phononic Crystal-Based Liquid Sensors

2019

Periodic elastic composite structures attract great attention. They offer the ability to design artificial properties to advance the control over the propagation of elastic/acoustic waves. In previous work, we drew attention to composite periodic structures comprising liquids. It was shown that the transmission spectrum of the structure, specifically a well-isolated peak, follows the material properties of liquid constituent in a distinct manner. This idea was realized in several liquid sensor concepts that launched the field of phononic crystal liquid sensors. In this work we introduce a novel concept&mdash

Thermo-hygrometry and IAQ Related Measurements of the Indoor Physical Conditions of Exhibition Halls for Complying International Rules and Standards

2018

Off-line methods for detecting the indoor physical parameters of museums are important tools in order of continuously monitoring the conditions at which works of art are exposed. These conditions, in fact, are mandatory established by several rules and technical standards aimed at preserving the specific artifacts. Moreover, indoor microclimate parameters must also take into account the comfort conditions for visiting people. Both the above-cited requirements suggest to perform the indoor monitoring with equipment visually low impacting. In this paper, some examples of visually low impacting off-line monitoring methods, applied to three artifacts displayed in the “Museo Regionale” of Palerm…

The Wide Field Imager of the International X-ray Observatory

2010

The International X-ray Observatory (IXO) will be a joint X-ray observatory mission by ESA, NASA and JAXA. It will have a large effective area (3 m 2 at 1.25 keV) grazing incidence mirror system with good angular resolution (5 arcsec at 0.1–10 keV) and will feature a comprehensive suite of scientific instruments: an X-ray Microcalorimeter Spectrometer, a High Time Resolution Spectrometer, an X-ray Polarimeter, an X-ray Grating Spectrometer, a Hard X-ray Imager and a Wide-Field Imager. The Wide Field Imager (WFI) has a field-of-view of 18 ft � 18 ft. It will be sensitive between 0.1 and 15 keV, offer the full angular resolution of the mirrors and good energy resolution. The WFI will be imple…