From Science direct: One of the nanowires was covered with a 2-Hydroxyethyl methacrylate based compound to prevent hydrogen from reaching the wire. The compound was dried by a UV source and tested in chamber for comparison with previous measurements. The results shows that temperature effects can be reduced by a digital signal processing algorithm without measuring temperature near or at the substrate. With this method no additional temperature probes are necessary making this solution a candidate for ultra low power wireless applications.
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from the article: The demand for a wireless CO2 solution is ever increasing. One of the biggest problems with the majority of commercial available CO2 sensors is the high energy consumption which makes them unsuitable for battery operation. Possible candidates for CO2 sensing in a low power wireless application are very limited and show a problematic calibration process. This study focuses on one of those EMF candidates, which is a Ag4RbI5 based sensor. This EMF sensor is based on the potentiometric principle and consumes no energy. The EMF cell was studied in a chamber where humidity, temperature and CO2 level could be controlled. This study gives an detailed insight in the different drift properties of the potentiometric CO2 sensor and a method to amplify the sensors signal. Furthermore, a method to minimize the several types of drift is given. With this method the temperature drift can be decreased by a factor 10, making the sensor a possible candidate for a wireless CO2 sensor network.
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Author supplied from the article: Abstract A temperature compensated hydrogen sensor was designed and made capable of detecting H2 within a broad range of 100–10.000 ppm while compensating instantaneously for large (±25 °C) temperature variations. Two related operational constraints have been simultaneously addressed: (1) Selective, and sensitive detection under large temperature changes, (2) Fast warning at low and increasing H2 levels. Accurate measurements of hydrogen concentrations were enabled by matching relevant time-constants. This was achieved with a microchip having two temperature coupled palladium nanowires. One of the H2 sensitive Pd nanowires was directly exposed to hydrogen, whilst the other nanowire was used as a temperature sensor and as a reference. A drop forging technique was used to passivate the second Pd wire against H2 sensing. Temperature effects could be substantially reduced with a digital signal processing algorithm. Measurements were done in a test chamber, enabling the hydrogen concentration to be controlled over short and long periods. An early response for H2 sensing is attainable in the order of 600 milliseconds and an accurate value for the absolute hydrogen concentration can be obtained within 15 s.
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Dit onderzoek is bedoeld om de huidige labelvorming van kinderen met luisterproblemen te onderzoeken en om in samenwerking met logopedisten en audiologen in Nederland te komen tot een uniforme en hanteerbare definitie en om de kennis en ervaring op het gebied van signalering, diagnostiek en behandeling te bundelen. De aanleiding voor dit promotieonderzoek zijn de vragen vanuit het werkveld (logopedisten, audiologen, psychologen AC) over AVP die tijdens presentaties op diverse congressen, in logopedische kwaliteitskringen en dyslexiekringen in de periode 2008-2012 en tijdens de studiedag “Diagnostiek van auditieve verwerkingsproblemen” van de FENAC op 21 mei 2014 (http://www.fenac.nl/algemeen/opleiding/studiedag-avp/studiedag-diagnostiek-van-auditieve-verwerkingsproblemen-avp.html) gesteld werden.
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Brochure from the Inauguration of Klaas Dijkstra, professor Computer Vision and Data Science
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Standard SARS-CoV-2 testing protocols using nasopharyngeal/throat (NP/T) swabs are invasive and require trained medical staff for reliable sampling. In addition, it has been shown that PCR is more sensitive as compared to antigen-based tests. Here we describe the analytical and clinical evaluation of our in-house RNA extraction-free saliva-based molecular assay for the detection of SARS-CoV-2. Analytical sensitivity of the test was equal to the sensitivity obtained in other Dutch diagnostic laboratories that process NP/T swabs. In this study, 955 individuals participated and provided NP/T swabs for routine molecular analysis (with RNA extraction) and saliva for comparison. Our RT-qPCR resulted in a sensitivity of 82,86% and a specificity of 98,94% compared to the gold standard. A false-negative ratio of 1,9% was found. The SARS-CoV-2 detection workflow described here enables easy, economical, and reliable saliva processing, useful for repeated testing of individuals.
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The nonlinearity induced by light-emitting diodes in visible light communication (VLC) systems presents a challenge to the parametrization of orthogonal frequency division multiplexing (OFDM). The goal of the multi-objective optimization problem presented in this study is to maximize the transmitted power (superimposed LED bias-current and signal amplification) for both conventional and constant envelope (CE) OFDM while also maximizing spectral efficiency. The bit error rate (BER) metric is used to evaluate the optimization using the non-dominated sorting genetic algorithm II. Simulation results show that for a BER of 1×10 −3 , the signal-to-noise ratio (SNR) required decreases with the guard band due to intermodulation distortions. In contrast to SNR values of approximately 13 and 25 dB achieved by traditional OFDM-based systems, the VLC system with CE signals achieves a guard band of 6% of the signal bandwidth with required SNR values of approximately 10.8 and 24 dB for 4-quadrature amplitude modulation (QAM) and 16-QAM modulation orders, respectively.
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This paper describes the concept of a new algorithm to control an Unmanned Aerial System (UAS) for accurate autonomous indoor flight. Inside a greenhouse, Global Positioning System (GPS) signals are not reliable and not accurate enough. As an alternative, Ultra Wide Band (UWB) is used for localization. The noise is compensated by combining the UWB with the delta position signal from a novel optical flow algorithm through a Kalman Filter (KF). The end result is an accurate and stable position signal with low noise and low drift.
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This paper describes experiments with a game device that was used for early detection of delays in motor skill development in primary school children. Children play a game by bi-manual manipulation of the device which continuously collects ac- celerometer data and game state data. Features of the data are used to discriminate between normal children and children with delays. This study focused on the feature selection. Three features were compared: mean squared jerk (time domain); power spectral entropy (fourier domain) and cosine similarity measure (quality of game play). The discriminatory power of the features was tested in an experiment where 28 children played games of different levels of difficulty. The results show that jerk and cosine similarity have reasonable discriminatory power to detect fine-grained motor skill development delays especially when taking the game level into account. Duration of a game level needs to be at least 30 seconds in order to achieve good classification results.
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This work is on 3-D localization of sensor motes in massive swarms based solely on 1-D relative distance-measurements between neighbouring motes. We target applications in remote and difficult-to-access environments such as the exploration and mapping of the interior of oil reservoirs where hundreds or thousands of motes are used. These applications bring forward the need to use highly miniaturized sensor motes of less than 1 centimeter, thereby significantly limiting measurement and processing capabilities. These constraints, in combination with additional limitations posed by the environments, impede the communication of unique hardware identifiers, as well as communication with external, fixed beacons.
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