Search results for " Sensor"
showing 10 items of 1714 documents
REDESIGN OF AN AUTO-LEVELLING BASE FOR SUBMARINE SEISMIC SENSOR
2011
The OBS (acronym of Ocean Bottom Seismometer) is a system to monitor the submarine seismic activity. To properly work, an OBS system needs a suitable auto-levelling base to maintain a fixed (horizontal) position during the measurement phases. In this work a new auto-levelling base for submarine seismic sensors has been designed. During the redesign process a preliminary phase of analysis of the state of art has been made. Afterwards, the technological solutions chosen by different manufactures have been critically analysed, and a full description of their functionalities, working principles and system performances has been carried out. Later, some innovative concepts have been proposed. Amo…
Autocorrelation Metrics to Estimate Soil Moisture Persistence From Satellite Time Series: Application to Semiarid Regions
2021
Satellite-derived soil moisture (SM) products have become an important information source for the study of land surface processes in hydrology and land monitoring. Characterizing and estimating soil memory and persistence from satellite observations is of paramount relevance, and has deep implications in ecology, water management, and climate modeling. In this work, we address the problem of SM persistence estimation from microwave sensors using several autocorrelation metrics that, unlike traditional approaches, build on accurate estimates of the autocorrelation function from nonuniformly sampled time series. We show how the choice of the autocorrelation estimator can have a dramatic impac…
DETERMINATION OF TDC IN INTERNAL COMBUSTION ENGINES BY A NEWLY DEVELOPED THERMODYNAMIC APPROACH
2010
Abstract In-cylinder pressure analysis is nowadays an indispensable tool in internal combustion engine research & development. It allows the measure of some important performance related parameters, such as indicated mean effective pressure (IMEP), mean friction pressure, indicated fuel consumption, heat release rate, mass fraction burned, etc. Moreover, future automotive engine will probably be equipped with in-cylinder pressure sensors for continuous combustion monitoring and control, in order to fulfil the more and more strict emission limits. For these reasons, in-cylinder pressure analysis must be carried out with maximum accuracy, in order to minimize the effects of its characteristic…
Application of propidium monoazide-qPCR to evaluate the ultrasonic inactivation of Escherichia coli O157:H7 in fresh-cut vegetable wash water.
2012
The efficacy of sanitizing technologies in produce or in vegetable wash water is generally evaluated by plate count in selective media. This procedure is time consuming and can lead to misinterpretations because environmental conditions and sanitizing processes may affect bacterial growth or culturable capability. Thus, the aim of this study was to determine the applicability of a propidium monoazide real-time PCR (PMA-qPCR) method to monitor the inactivation by ultrasound treatment of foodborne bacteria in fresh-cut vegetable wash water. To this aim, lettuce wash water was artificially inoculated with Escherichia coli O157:H7 (10⁶ CFU/mL) and treated by means of a continuous ultrasonic irr…
Assessment of the Potential future high and medium resolution sensors on geosynchronous orbit for coastal zone monitoring
2009
Geosynchronous satellite can measure any area with high temporal repetitivity within its coverage region because of its relative static location compared to Earth. Considering the temporal repetitivity, it can satisfy requirements for coastal zone monitoring but also has to face the influence of the varying solar angle and sensor angle (zenith and azimuth). Up to now, there is no geosynchronous sensor dedicated to ocean color monitoring (a geosynchronous sensor "Korea Geostationary Ocean Color Imager" (KGOCI) is supposed to be launched in 2009 [1]). To obtain radiances from the ocean at 36000km of altitude, we have to use a simulation model. In this conference, we present generic model of s…
Construction of Disjoint Virtual Backbones for Wireless Sensor Networks
2020
A wireless sensor network is a wireless network of sensors aimed at monitoring physical events. It has ingratiated itself into almost all areas of human endeavors. Data dissemination in these networks is quite challenging and is generally accomplished by flooding. But flooding introduces broadcast storm problem due from implosion and overlap. To overcome this, topology management can prescribe a virtual backbone network to which routing is confined. In this paper we propose an algorithm that constructs multiple disjoint virtual backbone networks, using only nodes' locations. The disjointedness makes routing more robust and the network exploitation energy efficient. Simulations show our algo…
RoadMic: Road Surface Monitoring Using Vehicular Sensor Networks with Microphones
2010
Road surface analysis including pothole reports is an important problem for road maintainers and drivers. In this paper we propose a methodology for pothole detection using mobile vehicles equipped with off the shelf microphone and global positioning devices attached to an on-board computer. The approach is generic enough to be extended for other kind of event detection using different sensors as well. The vehicles are driving on public streets and measuring pothole induced sound signals. Our approach was tested and evaluated by real world experiments in a road segment for which we had established the ground truth beforehand. The results show pothole detection with high accuracy despite the…
Passive RFID Strain-Sensor Based on Meander-Line Antennas
2011
The processing of backscattered signals coming from RFID tags is potentially useful to detect the physical state of the tagged object. It is here shown how to design a completely passive UHF RFID sensor for strain monitoring starting from a flexible meander-line dipole whose shape factor and feed section are engineered to achieve the desired sensing resolution and dynamic range. This class of devices is low-cost, promises sub-millimeter resolution and may found interesting applications in the Structural Health Monitoring of damaged structures and vehicles as well as during extreme and adverse events.
Multimode WSN: Improving Robustness, Fault Tolerance and Performance of Randomly Deployed Wireless Sensor Network
2010
This paper proposes an advanced, robust and flexible solution that applies the (revised) concept of Always Best Connected (ABC) Network, typical of multimode modern mobile devices, to Wireless Sensor Network. Hostile environments and unpredictable conditions (e.g. interferences) can negatively affect communication range, potentially increasing the number of unconnected nodes in random deployments. Multimode Wireless Sensor Network (MM-WSN) is provided with an adaptive mechanism for environmental condition evaluation and with the ability of self-configuring itself for optimal networking independence of detected conditions. Proposed solution is based on advanced smart nodes provided with mult…
Predicting the Batteries' State of Health in Wireless Sensor Networks Applications
2018
[EN] The lifetime of wireless sensor networks deployments depends strongly on the nodes battery state of health (SoH). It is important to detect promptly those motes whose batteries are affected and degraded by ageing, environmental conditions, failures, etc. There are several parameters that can provide significant information of the battery SoH, such as the number of charge/discharge cycles, the internal resistance, voltage, drained current, temperature, etc. The combination of these parameters can be used to generate analytical models capable of predicting the battery SoH. The generation of these models needs a previous process to collect dense data traces with sampled values of the batt…