56 research outputs found

    Towards Efficient In-memory Computing Hardware for Quantized Neural Networks: State-of-the-art, Open Challenges and Perspectives

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    The amount of data processed in the cloud, the development of Internet-of-Things (IoT) applications, and growing data privacy concerns force the transition from cloud-based to edge-based processing. Limited energy and computational resources on edge push the transition from traditional von Neumann architectures to In-memory Computing (IMC), especially for machine learning and neural network applications. Network compression techniques are applied to implement a neural network on limited hardware resources. Quantization is one of the most efficient network compression techniques allowing to reduce the memory footprint, latency, and energy consumption. This paper provides a comprehensive review of IMC-based Quantized Neural Networks (QNN) and links software-based quantization approaches to IMC hardware implementation. Moreover, open challenges, QNN design requirements, recommendations, and perspectives along with an IMC-based QNN hardware roadmap are provided

    Theory of diffusive light scattering cancellation cloaking

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    We report on a new concept of cloaking objects in diffusive light regime using the paradigm of the scattering cancellation and mantle cloaking techniques. We show numerically that an object can be made completely invisible to diffusive photon density waves, by tailoring the diffusivity constant of the spherical shell enclosing the object. This means that photons' flow outside the object and the cloak made of these spherical shells behaves as if the object were not present. Diffusive light invisibility may open new vistas in hiding hot spots in infrared thermography or tissue imaging.Comment: 16 pages, 5 figure

    Reliable High-Frequency Fabricated Fractional-Order Capacitors and Their Passive Circuit Models

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    The impedance characteristics of three different type of fractional-order capacitors (FOCs) with an order of -0.74, -0.79, and -0.91 are analyzed. The used devices have excellent feature such as constant phase angle in the frequency range 10 MHz - 100 MHz. Their impedance data is fitted with second-order passive electrical model structures of Foster-I abd Foster-II using standard EIA-48 compliant component values phase error. The effect on phase and pseudo-capacitance using a detailed experimental study of series-, parallel-, and inter-connected FOCs is also shown

    Development of Primary Percutaneous Coronary Intervention as a National Reperfusion Strategy for Patients with ST-Elevation Myocardial Infarction and Assessment of Its Use in Egypt

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    Objective: Early treatment of acute ischemia of the heart by performing immediate percutaneous coronary intervention (PCI) to restore blood flow in patients with the clinical presentation of an acute coronary syndrome and more specifically with ST-elevation myocardial infarction (STEMI) can save lives. This study aims to identify the mean time (door to balloon time and first contact to balloon time) to primary PCI for STEMI patients and to assess the percentage of primary PCI and its success rate in Egypt. Methods: A registry study of patients presenting to cardiac centers in Egypt was designed, where patients’ basic characteristics, the treatment strategy, and the door to balloon time and the first contact to balloon time were assessed. Results: One thousand six hundred fifty STEMI patients with a mean age of 57 years were included in the study. Immediate transfer for primary PCI was the most used treatment strategy, representing 74.6% of all treatment strategies used. The door to balloon time and the first contact to balloon time were 50 and 60 minutes, respectively, with a primary PCI success rate of 65.1%. Conclusion: The registry study results showed a marked improvement by implementation of the best treatment strategy with respect to the time factor to achieve a better outcome for STEMI patients in Egypt

    Effects of hospital facilities on patient outcomes after cancer surgery: an international, prospective, observational study

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    Background Early death after cancer surgery is higher in low-income and middle-income countries (LMICs) compared with in high-income countries, yet the impact of facility characteristics on early postoperative outcomes is unknown. The aim of this study was to examine the association between hospital infrastructure, resource availability, and processes on early outcomes after cancer surgery worldwide.Methods A multimethods analysis was performed as part of the GlobalSurg 3 study-a multicentre, international, prospective cohort study of patients who had surgery for breast, colorectal, or gastric cancer. The primary outcomes were 30-day mortality and 30-day major complication rates. Potentially beneficial hospital facilities were identified by variable selection to select those associated with 30-day mortality. Adjusted outcomes were determined using generalised estimating equations to account for patient characteristics and country-income group, with population stratification by hospital.Findings Between April 1, 2018, and April 23, 2019, facility-level data were collected for 9685 patients across 238 hospitals in 66 countries (91 hospitals in 20 high-income countries; 57 hospitals in 19 upper-middle-income countries; and 90 hospitals in 27 low-income to lower-middle-income countries). The availability of five hospital facilities was inversely associated with mortality: ultrasound, CT scanner, critical care unit, opioid analgesia, and oncologist. After adjustment for case-mix and country income group, hospitals with three or fewer of these facilities (62 hospitals, 1294 patients) had higher mortality compared with those with four or five (adjusted odds ratio [OR] 3.85 [95% CI 2.58-5.75]; p<0.0001), with excess mortality predominantly explained by a limited capacity to rescue following the development of major complications (63.0% vs 82.7%; OR 0.35 [0.23-0.53]; p<0.0001). Across LMICs, improvements in hospital facilities would prevent one to three deaths for every 100 patients undergoing surgery for cancer.Interpretation Hospitals with higher levels of infrastructure and resources have better outcomes after cancer surgery, independent of country income. Without urgent strengthening of hospital infrastructure and resources, the reductions in cancer-associated mortality associated with improved access will not be realised

    The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

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    INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

    Stochasticity Modeling in Memristors

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    CMOS-RC Colpitts Oscillator Design Using Floating Fractional-Order Inductance Simulator

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    This paper deals with CMOS fractional-order inductance (FoL) simulator design and its utilization in 2.75th-order Colpitts oscillator providing high frequency of oscillation. The proposed floating FoL is composed of two unity-gain current followers (CF +/- s), two inverting voltage buffers, a transconductor, and a fractional-order capacitor (FoC) of order 0.75, while the input intrinsic resistance of CF. is used as design parameter instead of passive resistor. The resulting equivalent inductance value of the FoL can be adjusted via order of FoC, which was emulated via 5th-order Foster II RC network and values optimized using modified least squares quadratic method. In frequency range 138 kHz -2.45 MHz the L. shows +/- 5 degree phase angle deviation. Theoretical results are verified by SPICE simulations using TSMC 0.18 mu m level-7 LO EPI SCN018 CMOS process parameters with +/- 1 V supply voltages
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