Search results for " sensor"
showing 10 items of 1714 documents
A Novel Wireless Sensor Network for Electric Power Metering
2013
Wireless sensor network with lightweight and efficient communication infrastructures are today a great interest, both at research and industrial level, as they are the basis for reliable monitoring services. Mesh networks are ideal candidates in this scenario, as they can be very fault-tolerant. After introducing wireless network systems requirements, we show the design of a mesh network routing protocol based on AODV schemas. Its implementation runs on top of low-cost off-the-shelf components, and allowed us to build a custom power meter wireless sensor node.
The Combitube, Self-Inflating Bulb, and Colorimetric Carbon Dioxide Detector to Advance Airway Management in the First Echelon of the Battlefield
2006
Combat lifesavers and Army medics are regular combat soldiers who possess skills that enable them to provide lifesaving assistance to combat casualties. Although their training is not equal to that of paramedics, combat lifesavers and Army medics are trained to assess casualties for airway obstruction, as well as the presence or absence of spontaneous ventilation. They are also familiar with the same basic airway maneuvers that are required for blind insertion of the esophageal-tracheal double-lumen airway (ETDLA). Use of the ETDLA in combination with an esophageal detector device and a colorimetric carbon dioxide detector would require skill similar to that which they already possess in pe…
Optimal placement of quality sensors in water distribution systems
2019
Water supply infrastructures are crucial for the sustainable existence and development of modern cities [1,2]. Water distribution systems (WDSs) are complex structures formed by many elements designed and erected to transport water of sufficient quality from water sources to consumers. The amount of the above elements, which can reach up to tens of thousands of links and junctions, their frequently wide spatial dispersion and the WDS characteristic of being very dynamic structures make the management of real WDSs a complex problem [3-5]. Moreover, although the main objective is to supply water in the quantity and quality required, other requirements are essential, namely maintaining conditi…
Wavefront sensing using a graphical user interface
2015
Contract grant sponsor: Ministerio de Economia y Competividad; Contract grant number: FIS2011-23175; Contract grant sponsor: Generalitat Valenciana; Contract grant number: PROMETEOII/2014/072; Contract grant sponsor: Universitat de Valencia; Contract grant number: UV-SFPIE_DINV14-222801
Dynamic wavefront sensing and correction with low-cost twisted nematic spatial light modulators
2010
Off-the-shelf spatial light modulators (SLMs), like twisted nematic liquid crystal displays (TNLCDs) used in projection systems, show some interesting features such as high spatial resolution, easy handling, wide availability, and low cost. We describe a compact adaptive optical system using just one TNLCD to measure and compensate optical aberrations. The current system operates at a frame rate of the order of 10 Hz with a four-level codification scheme. Wavefront estimation is performed through conventional Hartmann–Shack sensing architecture. The system has proved to work properly with a maximum rms aberration of 0. 76 μm and wavefront gradient of 50 rad/mm at a wavelength of 514 nm. The…
Optical phase retrieval using four rotated versions of a single binary amplitude modulating mask
2019
In recent years, phase retrieval methods recovering the phase of an object from coded diffraction patterns have gained popularity. A numerical phase retrieval method called PhaseLift that recovers the phase of an object from a very limited number of coded diffraction patterns was recently proposed. Performance of PhaseLift has been analyzed for different types and the number of masks modulating an object. We present a unique application of PhaseLift that uses four rotations of a single mask, modulating only the amplitude of an object. In simulations, a phase screen with the root-mean-square (RMS) value 0.294 μm was used as the test object. The RMS value of the retrieved phase screen after …
Drifts in real-time partial wavefront correction and how to avoid them
2017
In visual experiments that require real-time partial correction of wavefront aberrations, small errors occur that accumulate over time and lead to drifts in Zernike coefficients of the uncorrected aberrations. A simple algorithm that does not require the inclusion of an additional optical path to obtain independent measurements of the eye's aberrations is described here, and its effectiveness in preventing these drifts is demonstrated.
Hyperspectral imager calibration using ceramic color tiles (Conference Presentation)
2019
Sets of chromatic and neutral ceramic tiles are widely used as measurement standards for reflectance factors in color applications. The usual instrument for color measurements is a spectrophotometer that measures the tiles using either a 0:45 or 45:0 illumination and viewing geometry, or with an integrating sphere in order to measure the reflectance factor in either specular excluded or specular included conditions. Having the corresponding measurements of the tile set from a calibrated instrument, systematic errors in the instrument under study can be diagnosed and corrected using a model of the errors and fitting it to the difference in measurements. One such is the Berns-Petersen model, …
Total ionizing dose (TID) evaluation of magnetic tunnel junction (MTJ) current sensors
2015
Abstract The paper shows an experimental study to know the behaviour of tunnel magnetoresistive effect-based current sensors configured in a Wheatstone bridge in response to irradiation. In particular the sensitivity, hysteresis, output offset voltage and input resistance are discussed when the sensors are submitted to a total irradiation dose of 43 krad with 36 krad/h dose rate. The same electrical parameters were studied subsequently once the irradiated sensors were submitted to an 80 °C annealing process. The studied TMR sensors are applied in a switched-mode power converter for space application.
Electrical Characterization of a Magnetic Tunnel Junction Current Sensor for Industrial Applications
2012
The objective of the work was the design of a Wheatstone bridge current sensor using MTJ as magnetoresistive elements. Each one of the four resistances of the bridge consists on 360 MTJ single elements connected in series for improved electrical robustness. A printed circuit board (PCB) was designed with a U-shaped copper trace placed under the PCB maintaining a 1.1 mm separation distance between sensor and trace. A 160% of tunnel magnetoresistance effect in the single junction and a 120% in its corresponding series elements connection has been achieved with a sensitivity of 9.2 Ω/Oe in a 65 Oe linear range. The DC sensor sensitivity in response to an external DC current sweeps of ±10, ±20,…