81 research outputs found
An improved neural network technique for data dimensionality reduction in satellite imagery
This paper presents an application of back-propagation neural network based mapping scheme of multispectrale data images.
The approach exploits the ability of neural networks for non-linear projection of multidimensional data, and their advantages
over traditional methods. An updating rule for this network, based on the Conjugate Gradient Algorithm is used. The main
advantage of this algorithm is the speedup of the convergence rate. Performance evaluation using a Landsat image of KĂ©nitra
region (Morocco) is carried out. Classification results of the proposed algorithm outperform those obtained using conventional
methods.Ce papier prĂ©sente une nouvelle technique de rĂ©duction du nombre de canaux spectraux pour aider Ă la classification des images multispectrales en mode d'occupation du sol. Cette technique, basĂ©e sur des rĂ©seaux de neurones multicouches, propose une rĂšgle d'apprentissage de ces rĂ©seaux qui adapte le gradient conjuguĂ© Ă la mĂ©thode de rĂ©tropropagation; permettant ainsi une convergence rapide au rĂ©seau. Les rĂ©sultats de classification sont Ă©valuĂ©s sur une fenĂȘtre d'image Landsat-TM de 512*512 pixels, relative Ă la rĂ©gion de KĂ©nitra (Maroc), et comparĂ©s Ă ceux obtenus par les mĂ©thodes classiques
FastIC: a fast integrated circuit for the readout of high performance detectors
This work presents the 8-channel FastIC ASIC developed in CMOS 65ânm technology suitable for the readout of positive and negative polarity sensors in high energy physics experiments, Cherenkov detectors and time-of-flight systems. The front-end can be configured to perform analog summation of up to 4 single-ended channels before discrimination in view of improving time resolution when segmenting a SiPM. The outputs encode the time-of-arrival information and linear energy measurement which captures the peak amplitude of the input signal in the 5 ”Aâ25 mA input peak current range. Power consumption of the ASIC is 12 mW/ch with default settings. Measurements of single photon time resolution with a red-light laser source and a HPK SiPM S13360-3050CS are â140âps FWHM
Quantum numbers of the X (3872 ) state and orbital angular momentum in its Ï0J /Ï decay
Angular correlations in B+ â X(3872)K+ decays, with X(3872) â Ï 0J/Ï, Ï 0 â Ï +Ï â and J/Ï â ” +” â, are used to measure orbital angular momentum contributions and to determine the J P C value of the X(3872) meson. The data correspond to an integrated luminosity of 3.0 fbâ1 of proton-proton collisions collected with the LHCb detector. This determination, for the first time performed without assuming a value for the orbital angular momentum, confirms the quantum numbers to be J P C = 1++. The X(3872) is found to decay predominantly through S wave and an upper limit of 4% at 95% C.L. is set on the D-wave contribution
HRFlexToT: A High Dynamic Range ASIC for Time-of-Flight Positron Emission Tomography
Abstract: Time-of-Flight positron emission tomography scanners demand fast and efficient photo sensors and scintillators coupled to fast readout electronics. This article presents the high resolution flexible Time-over-Threshold (HRFlexToT), a 16-channel application-specific-integrated circuit for silicon photomultipliers (SiPM) anode readout manufactured using XFAB 0.18- ÎŒm CMOS technology. The main features of the HRFlexToT are a linear Time-over-Threshold with an extended dynamic range (10 bits) for energy measurement, low power consumption (â 3.5 mW/ch), and an excellent timing response. The experimental measurements show an energy linearity error of â 3% and an energy resolution of about 12% at 511 keV. Single-photon time resolution measurements performed using an Fondazione Bruno Kessler (FBK) SiPM NUV-HD ( 4Ă4 mm2 pixel, 40- ÎŒm cell) and a Hamamatsu SiPM S13360-3050CS are around 142 and 167 ps full width at half maximum (FWHM), respectively. Coincidence time resolution (CTR) measurements with small cross-section pixelated crystals (LSO:Ce,Ca 0.4%, 2Ă2Ă5 mm3) coupled to the same Hamamatsu S13360-3050CS and FBK NUV-HD sensors yield a CTR of 117 ps and 119 ps, respectively. Measurements performed with a large cross-section monolithic crystal (LFS crystal measuring 25Ă25Ă20 mm3) and a Hamamatsu SiPM array S13361-6050NE-04 show a CTR of 324 ps FWHM after time-walk and time-skew correction
A High Dynamic Range ASIC for Time of Flight PET with monolithic crystals
The HRFlexToT is a 16-channel ASIC for SiPM anode readout designed for Positron Emission Tomography (PET) applications that features high dynamic range (>8 bits), low input impedance, common cathode connection, high speed and low power (~3.5 mW/ch). The ASIC has been manufactured using XFAB 0.18 mm CMOS technology. The main characteristics of the HRFlexToT, compared to its predecessor, are a new energy measurement readout providing a linear Time Over Threshold (ToT) with an extended dynamic range, lower power consumption and better timing response. Initial measurements show a linearity error below 3%. Single Photon Time Resolution (SPTR) measurements performed using a Hamamatsu MPPC S13360-3050CS (3x3 mm2 pixel, 50 umm cell) shows 30% improvement with respect to the previous version of the ASIC, setting this specification in the order of 141 ps FWHM and reducing 3 times power consumption. It is important to highlight that an SPTR of 141 ps FWHM is, according to the best of our knowledge, the best resolution achieved so far for this sensor. Coincidence Time Resolution (CTR) measurements are expected to be performed during 2018
Personalizing Cancer Pain Therapy: Insights from the Rational Use of Analgesics (RUA) Group
Introduction: A previous Delphi survey from the Rational Use of Analgesics (RUA) project involving Italian palliative care specialists revealed some discrepancies between current guidelines and clinical practice with a lack of consensus on items regarding the use of strong opioids in treating cancer pain. Those results represented the basis for a new Delphi study addressing a better approach to pain treatment in patients with cancer. Methods: The study consisted of a two-round multidisciplinary Delphi study. Specialists rated their agreement with a set of 17 statements using a 5-point Likert scale (0 = totally disagree and 4 = totally agree). Consensus on a statement was achieved if the median consensus score (MCS) (expressed as value at which at least 50% of participants agreed) was at least 4 and the interquartile range (IQR) was 3â4. Results: This survey included input from 186 palliative care specialists representing all Italian territory. Consensus was reached on seven statements. More than 70% of participants agreed with the use of low dose of strong opioids in moderate pain treatment and valued transdermal route as an effective option when the oral route is not available. There was strong consensus on the importance of knowing opioid pharmacokinetics for therapy personalization and on identifying immediate-release opioids as key for tailoring therapy to patientsâ needs. Limited agreement was reached on items regarding breakthrough pain and the management of opioid-induced bowel dysfunction. Conclusion: These findings may assist clinicians in applying clinical evidence to routine care settings and call for a reappraisal of current pain treatment recommendations with the final aim of optimizing the clinical use of strong opioids in patients with cancer
- âŠ