130,502 research outputs found
Comparative Study on Pre-Distortion/Calibration Methods for Current-Steering Digital-to-Analog Converters
No full textThis paper introduces a variety of different pre-distortion/calibration methods for current-steering digital-to-analog converters (CS-DAC) and compares their respective performance. The comparison is done through simulations of the different methods with a static CS-DAC model in MATLAB and the subsequent calculation of the signal-to-distortion ratio (SDR) and the spurious-free dynamic range (SFDR). Since the requirements for high-speed, high-precision applications are becoming more and more stringent on the data converters the need for calibration methods becomes also increasingly important. A quantitative comparison can help to decide on the right method for different applications in terms of reducing the distortions resulting from the static current cell mismatch of CS-DACs. This paper extends upon the previous research by using different input signal types for the simulations
A Model-Based Approach Digital Pre-Distortion Method for Current-Steering Digital-to-Analog Converters
No full textThis paper presents a novel static digital pre-distortion (DPD) method for a current-steering digital-to-analog converter (CS-DAC). The proposed method utilizes the knowledge of the current cell array architecture to calculate the static mismatch currents of the cells. The mismatch values are stored in memory and added to the original input code to generate the new pre-distorted input word. The converter corrects the static error with its own current cells without incorporating an additional calibration DAC (CALDAC) or programmable current sources. This results in a reduction in area, power and simulation run times because of the simpler circuit design. An Overflow-Cell-Selection (OCS) is introduced as a novel solution to further enhance the static linearity of the converter. It also can be implemented as a software solution for already existing DAC designs which do not have an integrated DPD and lab/measurement equipment (e.g., arbitrary wave generator (AWG)). This poses as a strong differentiation factor compared to other state-of-the-art static DPD methods. The evaluation of the proposed DPD is done via simulations in MATLAB and on-chip measurements with a 14-bit CS-DAC in 16 nm. Single tone measurements show a performance gain of the total harmonic distortion (THD) of 12 dB
sj-pdf-1-prf-10.1177_02676591221078420 – Supplemental material Cell saver blood transfusions may be associated with a decrease in inflammation and improved outcome measures in pediatric cardiac surgery patients
No full textSupplemental material, sj-pdf-1-prf-10.1177_02676591221078420 for Cell saver blood transfusions may be associated with a decrease in inflammation and improved outcome measures in pediatric cardiac surgery patients by Michael J Martinez, Andreas Schwingshackl, Tahmineh Romero, Gavin D Roach, John A Belperio, and Myke D Federman in Perfusion</p
Static Digital Pre-Distortion Method for High-Speed Current-Steering Digital-to-Analog Converters
No full textThis paper presents a static digital pre-distortion (DPD) method for a current-steering digital-to-analog converter (CS-DAC). The proposed model utilizes the knowledge of the current cell array architecture to calculate the static mismatch currents of the cells. The mismatch values of all cells are stored in memory and added to the original input code to generate the new pre-distorted input word. The converter corrects the static error with its own current cells without incorporating an additional calibration DAC (CALDAC) or programmable current sources. This results in a reduction in area, power and simulation run times because of the simpler circuit design. The proposed method is able to use an information signal for the calibration phase, thus it is possible to be implemented as a background calibration. The evaluation of the proposed DPD is done via simulations in MATLAB with a 14-bit static CS-DAC model. The results show a performance gain of the signal-to-noise-plus-distortion ratio (SNDR) of up to 16dB
Comparison of contact parameters measured with two different friction rigs for nonlinear dynamic analysis
No full textThe accurate measurement of contact interface parameters is of great importance for nonlinear dynamic response computations since there is a lack of predictive capabilities for such input parameters. Several test rigs have been developed at different institutions, and a series of measurements published, but their reliability remains unknown due to a lack of direct comparisons. To somehow address this issue, a Round-Robin test campaign was performed including the high frequency friction rigs of Imperial College London and Politecnico di Torino. Comparable hysteresis loops were recorded on specimen pairs manufactured from the same batch of raw stainless steel, for a wide range of test conditions, including varying normal loads, sliding distances and nominal areas of contact. Measurements from the two rigs were compared to quantify the level of agreement between the two very different experimental setup, showing a reasonably good matching in the results, but also highlighting some differences. Results also demonstrated that loading conditions can strongly affect the contact parameters, and consequently their effect must be included in future nonlinear dynamic simulations for more reliable predictions
A Wireless Vibration Control Technique for Gas Turbine Blades Using Piezoelectric Plates and Contactless Energy Transfer
No full textMeSH term explosion and author rank improve expert recommendations
No full textInformation overload is an often-cited phenomenon that reduces the productivity, efficiency and efficacy of scientists. One challenge for scientists is to find appropriate collaborators in their research. The literature describes various solutions to the problem of expertise location, but most current approaches do not appear to be very suitable for expert recommendations in biomedical research. In this study, we present the development and initial evaluation of a vector space model-based algorithm to calculate researcher similarity using four inputs: 1) MeSH terms of publications; 2) MeSH terms and author rank; 3) exploded MeSH terms; and 4) exploded MeSH terms and author rank. We developed and evaluated the algorithm using a data set of 17,525 authors and their 22,542 papers. On average, our algorithms correctly predicted 2.5 of the top 5/10 coauthors of individual scientists. Exploded MeSH and author rank outperformed all other algorithms in accuracy, followed closely by MeSH and author rank. Our results show that the accuracy of MeSH term-based matching can be enhanced with other metadata such as author rank
Six degrees of freedom measurement with continuous scanning laser Doppler vibrometer
No full textThe dynamicresponseofastructurecanconsistofuptosixdegreesoffreedom(DOF).
Not allofthemmaybepresentatalltimesinastructure,butforadetailedfinite
elementmodelvalidationitisimportanttoprovideasmuchinformationaspossible.
CurrentcontacttransducerscanpickupacombinationofsomeofthementionedDOFs,
but arenotabletoprovideallsixDOFsfromasingletransducer.Severalcontact-less
transducers,suchasaScanningLaserDopplerVibrometer(SLDV),canbecombinedtoa
single measurementsystemthatallowsthedeterminationofuptothreetranslational
degreesoffreedomatapoint,buttheyarestillnotprovidingrotationalinformationas
the laserbeamisfixedtoapoint.ContinuouslyScanningLaserDopplerVibrometer
(CSLDV)methodscanpartlyovercomethisissuebytravellinginsmallcirclesaroundthe
measurementlocationandthusalsosensingtherotationaroundthethreeaxesata
point.AnintroductionofCSLDVmethodsformeasuringDOFsatapointisgiven,
focussingonamethodforcapturingupto5DOFsusingalens.However,thelenscan
make themeasurementofthein-planerotationverydifficultandimpractical.Thispaper
presentsanewtypeofscanningdevicewhichallowsmeasuringallsixdegreesof
freedomatameasurementlocationwithasinglesetupandasinglepointLDV,by
combiningvariablesmallcirclescans.Experimentalvalidationofthescanningheadis
presentedandthemeasurementofthelastDOF,thein-planerotation,isdemonstrated
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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