3,101 research outputs found
A distributed energy-balance melt model of an alpine debris-covered glacier
No full textDistributed energy-balance melt models have rarely been applied to glaciers with extensive supraglacial debris cover. This paper describes the development of a distributed melt model and its application to the debris-covered Miage glacier, western Italian Alps, over two summer seasons. Sub-debris melt rates are calculated using an existing debris energy-balance model (DEB-Model), and melt rates for clean ice, snow and partially debris-covered ice are calculated using standard energy-balance equations. Simulated sub-debris melt rates compare well to ablation stake observations. Melt rates are highest, and most sensitive to air temperature, on areas of dirty, crevassed ice on the middle glacier. Here melt rates are highly spatially variable because the debris thickness and surface type varies markedly. Melt rates are lowest, and least sensitive to air temperature, beneath the thickest debris on the lower glacier. Debris delays and attenuates the melt signal compared to clean ice, with peak melt occurring later in the day with increasing debris thickness. The continuously debris-covered zone consistently provides ~30% of total melt throughout the ablation season, with the proportion increasing during cold weather. Sensitivity experiments show that an increase in debris thickness of 0.035 m would offset 1°C of atmospheric warmin
A 23-μW Keyword Spotting IC With Ring-Oscillator-Based Time-Domain Feature Extraction
No full textThis article presents the first keyword spotting (KWS) IC that uses a ring-oscillator-based time-domain processing technique for its analog feature extractor (FEx). Its extensive usage of time-encoding schemes allows the analog audio signal to be processed in a fully time-domain manner except for the voltage-to-time conversion stage of the analog front end. Benefiting from fundamental building blocks based on digital logic gates, it offers better technology scalability compared to conventional voltage-domain designs. Fabricated in a 65-nm CMOS process, the prototyped KWS IC occupies 2.03 mm 2 and dissipates 23- power consumption, including analog FEx and digital neural network classifier. The 16-channel time-domain FEx achieves a 54.89-dB dynamic range for 16-ms frame shift size while consuming 9.3 . The measurement result verifies that the proposed IC performs a 12-class KWS task on the Google Speech Command dataset (GSCD) with >86% accuracy and 12.4-ms latency. Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Electronic
A 15-nW per Sensor Interference-Immune Readout IC for Capacitive Touch Sensors
No full textThis paper presents a readout IC that uses an asynchronous capacitance-to-digital-converter (CDC) to digitize the capacitance of a touch sensor. A power-efficient tracking algorithm ensures that the CDC consumes negligible power consumption in the absence of touch events. To facilitate its use in wake-on-touch applications, the CDC can be periodically triggered by a co-integrated ultra-low-power relaxation oscillator. At a 38-Hz scan rate, the readout IC consumes 15 nW per touch sensor, which is the lowest reported to date.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Electronic InstrumentationMicroelectronic
When Anxiety Meets Impulsivity: A Risk Factor for Poor Effortful Control
No full textLong viewed as opposing traits, anxiety and impulsivity are increasingly recognized for their co-occurrence. Yet, effortful control (EC) in the context of impulsivity and anxiety remains underexplored. EC refers to a group of self-regulatory functions, including inhibitory control (IC), attentional control (ATTC), and activation control (ACTC), that support goal-directed behaviour. This study examined the relationships among trait anxiety, impulsivity, and EC in 104 young adults. Participants completed self-report measures of trait anxiety (State Trait Anxiety Inventory), impulsivity (Barratt Impulsiveness Scale), and EC functions (Adult Temperament Questionnaire), along with a mixed antisaccade eye tracking task as a behavioural measure of IC. Participants were independently categorized into high- and low-anxiety groups, as well as high-and low-impulsivity groups using a median split. Independent samples t-test revealed that high-anxious (HA) participants did not significantly differ on antisaccade performance (antisaccade correct mean reaction time, antisaccade percent correct) compared to low-anxious (LA) participants, but HA participants self-reported lower levels of EC compared to LA participants. Group differences between high-impulsive (HI) and low-impulsive (LI) participants followed a similar pattern. Moderation results showed that trait anxiety was negatively related to self-reported attentional control, but only at low and medium levels of impulsivity. These findings highlight that the relationship between trait anxiety and EC, particularly ATTC, might differ depending on the level of impulsivity. Moreover, the observed discrepancy between self-report and behavioural measures of EC emphasizes the importance of using multi-method assessments to measure self-regulatory functions
A 20-bit ±40-mV Range Read-Out IC With 50-nV Offset and 0.04% Gain Error for Bridge Transducers
No full textThis paper presents a 20-b read-out IC with ±40-mV full-scale range that is intended for use with bridge transducers. It consists of a current-feedback instrumentation amplifier (CFIA) followed by a switched-capacitor incremental ΔΣ ADC. The CFIA's offset and 1/ f noise are mitigated by chopping, while its gain accuracy and gain drift are improved by applying dynamic element matching to its input and feedback transconductors. Their mismatch is reduced by a digitally assisted correction loop, which further reduces the CFIA's gain drift. Finally, bulk-biasing and impedance-balancing techniques are used to reduce the common-mode dependency of these transconductors, which would otherwise limit the achievable gain accuracy. The combination of these techniques enables the read-out IC to achieve 140-dB CMRR, a worst-case gain error of 0.04% over a 0-2.5 V common-mode range, a maximum gain drift of 0.7 ppm/°C and an INL of 5 ppm. After applying nested-chopping, the read-out IC achieves 50-nV offset, 6-nV/°C offset drift, a thermal noise floor of 16.2 nV/√Hz and a 0.1-mHz 1/ f noise corner. Implemented in a 0.7-μm CMOS technology, the prototype read-out IC consumes 270 μA from a 5-V supply.Accepted Author ManuscriptElectronic Instrumentatio
A 15nW Per Button Noise-Immune Readout IC for Capacitive Touch Sensor
No full textThis paper presents a readout IC that uses an asynchronous charge-redistribution-based capacitance-to-digital-converter (CDC) to digitize the capacitance of a touch sensor. Thanks to the power efficient tracking algorithm, the CDC consumes negligible power consumption in the absence of touch events. To facilitate stand-alone or wake-on-touch applications, the CDC can be periodically triggered by a co-integrated ultra-low power relaxation oscillator. At a 38 Hz scan-rate, the readout IC consumes 15 nW per touch sensor, which is the lowest reported to date.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Electronic InstrumentationMicroelectronic
A 1024-Channel 268 nW/pixel 36x36 μm<sup>2</sup>/ch Data-Compressive Neural Recording IC for High-Bandwidth Brain-Computer Interfaces
No full textThis paper presents a neural recording IC featuring lossy compression during digitization, thus preventing data deluge and enabling a compact active digital pixel design. The wired-OR-based compression discards unwanted baseline samples while allowing the reconstruction of spike samples. The IC features a 32x32 MEA with 36 μ m pixel pitch and consumes 268nW per pixel from a single 1V supply. It achieves 9.8 μ VRMS input-referred noise and 0.3-5kHz bandwidth, resulting in NEF/PEF of 3.7/14.1. Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Bio-Electronic
Tomographic particle-image velocimetry in an IC engine
No full textThe flow structures during the intake and compression phase within the cylinder of an internal combustion(IC)engine strongly influence the mixing and combustion process. To gain a better understanding of the flow field, fully three-dimensional quantitative measurement techniques have to be applied to the flow field. Analog off-axis holographic particle-image velocimetry is capable of resolving the whole flow field of an IC engine with very high resolution (van Overbrueggen et. al [21]). On the other hand, long processing procedures make this technique not feasible for a statistic flow field analysis. Tomographic particle-image velocimetry (Tomo-PIV) is another three-component/three-dimensional (3C/3D) measurement technique that could be used. It is digital and therefore possesses the advantage of relatively short processing time. In this study, cycle resolved tomographic particle-image velocimetry measurements are performed in a four-valve IC engine to resolve the highly three dimensional flow in a large area of the cylinder. The resolved volume has a size of about 60 x 60 x 80 mm3 for the 160? measurements. The three-dimensional structure of the flow field is analyzed for 80?, 160?, and 240? after top dead center (aTDC) during the intake and compression phase at an engine speed of 1,500 rpm. The flow fields are analyzed by ensemble-averaged velocity fields, turbulent kinetic energy (TKE), and the G1 vortex center criterion. The results provide detailed inside in the highly three-dimensional flow field inside an internal combustion engine and show the feasibility of tomographic PIV to resolve such a large volume in a complex geometry
On IC-Bag Based Systems
No full textIn this paper, we discuss the notion of IC-Bags as introduced by the author and some issues related to the systems development techniques associated with different phases Of IC-Bag based systems. We consider the situations where the hesitation factor associated with’ the count function is able to play a crucial role in defining the knowledge-base and the requirement specifications
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Sustainable Wellbeing in Belize: The Challenge of Diabetes
No full textThe purpose of this paper is to explore the dimensions of diabetes in Belize and its impact on sustainable wellbeing. Diabetes is the leading cause of death in Belize, with many contributing factors. The author identifies some of those factors as well as governmental and non-governmental efforts to reduce them. The author's research was partially funded by the Bridging Disciplines program of the School of Undergraduate Studies at The University of Texas at Austin, and conducted under the guidance of Dr. David Gibson of the IC² Institute.IC2 Institut
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