Asymptotically Optimal Approximation Algorithms for Coflow Scheduling

Many modern datacenter applications involve large-scale computations composed of multiple data flows that need to be completed over a shared set of distributed resources. Such a computation completes when all of its flows complete. A useful abstraction for modeling such scenarios is a {\em coflow}, which is a collection of flows (e.g., tasks, packets, data transmissions) that all share the same performance goal. In this paper, we present the first approximation algorithms for scheduling coflows over general network topologies with the objective of minimizing total weighted completion time. We consider two different models for coflows based on the nature of individual flows: circuits, and packets. We design constant-factor polynomial-time approximation algorithms for scheduling packet-based coflows with or without given flow paths, and circuit-based coflows with given flow paths. Furthermore, we give an $O(\log n/\log \log n)$-approximation polynomial time algorithm for scheduling circuit-based coflows where flow paths are not given (here $n$ is the number of network edges). We obtain our results by developing a general framework for coflow schedules, based on interval-indexed linear programs, which may extend to other coflow models and objective functions and may also yield improved approximation bounds for specific network scenarios. We also present an experimental evaluation of our approach for circuit-based coflows that show a performance improvement of at least 22% on average over competing heuristics.Comment: Fixed minor typo

Effect of face masks on interpersonal communication during the COVID-19 pandemic

Interpersonal communication has been severely affected during the COVID-19 pandemic. Protective measures, such as social distancing and face masks, are essential to mitigate efforts against the virus, but pose challenges on daily face-to-face communication. Face masks, particularly, muffle sounds and cover facial expressions that ease comprehension during live communication. Here, we explore the role of facial expressions in communication and we highlight how the face mask can hinder interpersonal connection. In addition, we offer coping strategies and skills that can ease communication with face masks as we navigate the current and any future pandemic

Mathematical Modelling in PET Studies

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COVID-19 pandemic: an insult over injury for Lebanon

The outbreak of the novel coronavirus disease in 2019 (COVID-19) caused a plethora of challenges worldwide and tested healthcare systems across the six continents. Lebanon had recently faced harsh political and economic crises. We aim to describe the effect of COVID-19 on an already crisis-stricken country. A descriptive analysis of the burden of COVID-19 pandemic on Lebanon was performed. Relevant data on COVID-19 was retrieved from the Lebanese Ministry of Public Health from February 21 till June 13th, 2020. Results obtained were analyzed and a literature review was performed. 1422 confirmed COVID-19 cases were identified and reported in Lebanon by June 13th, 2020, comprising an incidence rate of 208/million persons. There has been a total of 31 deaths thus far, with a reported death rate of 5/million persons. The age group with the highest number of cases was 20–29 years. Beirut was the district with the highest number of cases (18%). The COVID-19 crisis has impacted the country on a multifactorial level. COVID-19 could not have come at a worse time for Lebanon. The country is on brink of bankruptcy, the healthcare system is struggling for survival and the government is striving to regain the trust of the population

Re-architecting datacenter networks and stacks for low latency and high performance

© 2017 ACM. Modern datacenter networks provide very high capacity via redundant Clos topologies and low switch latency, but transport protocols rarely deliver matching performance. We present NDP, a novel datacenter transport architecture that achieves near-optimal completion times for short transfers and high flow throughput in a wide range of scenarios, including incast. NDP switch buffers are very shallow and when they fill the switches trim packets to headers and priority forward the headers. This gives receivers a full view of instantaneous demand from all senders, and is the basis for our novel, high-performance, multipath-aware transport protocol that can deal gracefully with massive incast events and prioritize traffic from different senders on RTT timescales. We implemented NDP in Linux hosts with DPDK, in a software switch, in a NetFPGA-based hardware switch, and in P4. We evaluate NDP's performance in our implementations and in large-scale simulations, simultaneously demonstrating support for very low-latency and high throughput.This work was partly funded by the SSICLOPS H2020 project (644866)

Salivary biomarkers for the diagnosis and monitoring of neurological diseases

Current research efforts on neurological diseases are focused on identifying novel disease biomarkers to aid in diagnosis, provide accurate prognostic information and monitor disease progression. With advances in detection and quantification methods in genomics, proteomics and metabolomics, saliva has emerged as a good source of samples for detection of disease biomarkers. Obtaining a sample of saliva offers multiple advantages over the currently tested biological fluids as it is a non-invasive, painless and simple procedure that does not require expert training or harbour undesirable side effects for the patients. Here, we review the existing literature on salivary biomarkers and examine their validity in diagnosing and monitoring neurodegenerative and neuropsychiatric disorders such as autism and Alzheimer\u27s, Parkinson\u27s and Huntington\u27s disease. Based on the available research, amyloid beta peptide, tau protein, lactoferrin, alpha-synuclein, DJ-1 protein, chromogranin A, huntingtin protein, DNA methylation disruptions, and micro-RNA profiles display a reliable degree of consistency and validity as disease biomarkers

3D Bio-convective nanofluid Bödewadt slip flow comprising gyrotactic microorganisms over a stretched stationary disk with modified Fourier law

The renowned Bödewadt flow problem is considered here for the case of Bio-convective nanofluid flow encompassing gyrotactic microorganisms over a stationary disk. The flow is initiated owing to the rotation of water-based nanofluid which is at a large distance from an immovable disk. The analysis is performed with modified Fourier law in a Darcy-Forchheimer spongy media accompanied by slip and zero mass flux conditions at the surface. The subject Bödewadt nanofluid flow is considered with gyrotactic microorganisms and Cattaneo-Christov (C-C) heat flux effects for the first time. Conformist Von Kármán relations are affianced to attain a similar governing system of differential equations. An efficient MATLAB software-based numerical scheme bvp4c is employed to address the envisaged novel mathematical model. An outstanding synchronization is achieved when a comparative statement is formulated in a limiting case. Outcomes of the proclaimed parameters versus involved distributions are discussed with logical reasoning. It is comprehended that the microorganism density boundary layer is prominent for higher values of the Peclet number. Furthermore, it is remarked that the fluid temperature is diminished for significant values of the thermal relaxation time

Intraoperative periprosthetic humeral fracture during reverse shoulder arthroplasty: a sequelae of prior biceps tenodesis

Intraoperative periprosthetic humeral fractures are a rare but debilitating complication of reverse shoulder arthroplasty and can occur during multiple stages of the procedure. Prior biceps tenodesis has been found to reduce cortical humeral strength and predispose the patient to humeral fracture. We present a case of a 68-year-old female with a previous history of biceps tenodesis due to an irreparable rotator cuff tear. Months later, and after symptoms persisted, a reverse shoulder arthroplasty was performed. During the surgery and while performing final reduction, a fracture line was observed involving the hole used for the previous tenodesis procedure. The fracture was repaired, and the patient reported favorable outcomes. We report several factors that might have contributed to sustenance of this intraoperative fracture including prior biceps tenodesis, use of a press fit humeral stem, and the sex of the patient.Level of evidence: V

Hepatic Glucose Metabolism of Diabetic Patient Evaluated by 18FDG PET Scan

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