33,647 research outputs found

    Parallel detrended fluctuation analysis for fast event detection on massive PMU data

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    ("(c) 2015 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works.")Phasor measurement units (PMUs) are being rapidly deployed in power grids due to their high sampling rates and synchronized measurements. The devices high data reporting rates present major computational challenges in the requirement to process potentially massive volumes of data, in addition to new issues surrounding data storage. Fast algorithms capable of processing massive volumes of data are now required in the field of power systems. This paper presents a novel parallel detrended fluctuation analysis (PDFA) approach for fast event detection on massive volumes of PMU data, taking advantage of a cluster computing platform. The PDFA algorithm is evaluated using data from installed PMUs on the transmission system of Great Britain from the aspects of speedup, scalability, and accuracy. The speedup of the PDFA in computation is initially analyzed through Amdahl's Law. A revision to the law is then proposed, suggesting enhancements to its capability to analyze the performance gain in computation when parallelizing data intensive applications in a cluster computing environment

    Parallel detrended fluctuation analysis for fast event detection on massive PMU data

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    ("(c) 2015 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works.")Phasor measurement units (PMUs) are being rapidly deployed in power grids due to their high sampling rates and synchronized measurements. The devices high data reporting rates present major computational challenges in the requirement to process potentially massive volumes of data, in addition to new issues surrounding data storage. Fast algorithms capable of processing massive volumes of data are now required in the field of power systems. This paper presents a novel parallel detrended fluctuation analysis (PDFA) approach for fast event detection on massive volumes of PMU data, taking advantage of a cluster computing platform. The PDFA algorithm is evaluated using data from installed PMUs on the transmission system of Great Britain from the aspects of speedup, scalability, and accuracy. The speedup of the PDFA in computation is initially analyzed through Amdahl's Law. A revision to the law is then proposed, suggesting enhancements to its capability to analyze the performance gain in computation when parallelizing data intensive applications in a cluster computing environment

    Detecting Distracted Driving with Deep Learning

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    © Springer International Publishing AG 2017Driver distraction is the leading factor in most car crashes and near-crashes. This paper discusses the types, causes and impacts of distracted driving. A deep learning approach is then presented for the detection of such driving behaviors using images of the driver, where an enhancement has been made to a standard convolutional neural network (CNN). Experimental results on Kaggle challenge dataset have confirmed the capability of a convolutional neural network (CNN) in this complicated computer vision task and illustrated the contribution of the CNN enhancement to a better pattern recognition accuracy.Peer reviewe

    Immune regulatory networks coordinated by glycans and glycan-binding proteins in autoimmunity and infection

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    The immune system is coordinated by an intricate network of stimulatory and inhibitory circuits that regulate host responses against endogenous and exogenous insults. Disruption of these safeguard and homeostatic mechanisms can lead to unpredictable inflammatory and autoimmune responses, whereas deficiency of immune stimulatory pathways may orchestrate immunosuppressive programs that contribute to perpetuate chronic infections, but also influence cancer development and progression. Glycans have emerged as essential components of homeostatic circuits, acting as fine-tuners of immunological responses and potential molecular targets for manipulation of immune tolerance and activation in a wide range of pathologic settings. Cell surface glycans, present in cells, tissues and the extracellular matrix, have been proposed to serve as “self-associated molecular patterns” that store structurally relevant biological data. The responsibility of deciphering this information relies on different families of glycan-binding proteins (including galectins, siglecs and C-type lectins) which, upon recognition of specific carbohydrate structures, can recalibrate the magnitude, nature and fate of immune responses. This process is tightly regulated by the diversity of glycan structures and the establishment of multivalent interactions on cell surface receptors and the extracellular matrix. Here we review the spatiotemporal regulation of selected glycan-modifying processes including mannosylation, complex Nglycan branching, core 2 O-glycan elongation, LacNAc extension, as well as terminal sialylation and fucosylation. Moreover, we illustrate examples that highlight the contribution of these processes to the control of immune responses and their integration with canonical tolerogenic pathways. Finally, we discuss the power of glycans and glycan-binding proteins as a source of immunomodulatory signals that could be leveraged for the treatment of autoimmune inflammation and chronic infection.This work was supported by grants from SSP: co-funded by the European Union (ERC, GlycanSwitch, 101071386). Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Research Council Executive Agency. Neither the European Union nor the granting authority can be held responsible for them. The work was also co-funded by EU GlycanTrigger-grant Agreement No: 101093997. Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or European Health and Digital Executive Agency. Neither the European Union nor the granting authority can be held responsible for them. SSP also acknowledges funding by “2022 LRA Lupus Innovation Award” and by “European Crohn’s and Colitis Organisation (ECCO) Pioneer Award 2021”. SSP also acknowledges the US Department of Defense, US Army Medical Research Acquisition Activity, FY18 Peer Reviewed Medical Research Program Investigator-Initiated Research Award (award number W81XWH1920053) as well as grant funded by the Portuguese Foundation for Science and Technology – FCT (EXPL/MED-ONC/0496/2021). IA acknowledges FCT for funding (2022.00337.CEECIND). JG acknowledges funding from ESCMID (ESCMID Research Grant 2022), ECCO (ECCO Grant 2023) and FCT (2020.00088.CEECIND). G.A.R acknowledges grants from the Argentinean Agency for Promotion of Science, Technology and Innovation (PICT 2017-0494, PICT-FBB 620 and PICT 2020-01552). The authors are also thankful for generous support from Sales (Argentina), Bunge & Born (Argentina), Baron (Argentina), Williams (Argentina) and Richard Lounsbery (USA) Foundations, as well as donations from Ferioli-Ostry and Caraballo families to GAR

    Some Variations on Maxwell's Equations

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    In the first sections of this article, we discuss two variations on Maxwell's equations that have been introduced in earlier work--a class of nonlinear Maxwell theories with well-defined Galilean limits (and correspondingly generalized Yang-Mills equations), and a linear modification motivated by the coupling of the electromagnetic potential with a certain nonlinear Schroedinger equation. In the final section, revisiting an old idea of Lorentz, we write Maxwell's equations for a theory in which the electrostatic force of repulsion between like charges differs fundamentally in magnitude from the electrostatic force of attraction between unlike charges. We elaborate on Lorentz' description by means of electric and magnetic field strengths, whose governing equations separate into two fully relativistic Maxwell systems--one describing ordinary electromagnetism, and the other describing a universally attractive or repulsive long-range force. If such a force cannot be ruled out {\it a priori} by known physical principles, its magnitude should be determined or bounded experimentally. Were it to exist, interesting possibilities go beyond Lorentz' early conjecture of a relation to (Newtonian) gravity.Comment: 26 pages, submitted to a volume in preparation to honor Gerard Emch v. 2: discussion revised, factors of 4\pi corrected in some equation

    Prospects for the development of odour baits to control the tsetse flies Glossina tachinoides and G. palpalis s.l.

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    Field studies were done of the responses of Glossina palpalis palpalis in Côte d'Ivoire, and G. p. gambiensis and G. tachinoides in Burkina Faso, to odours from humans, cattle and pigs. Responses were measured either by baiting (1.) biconical traps or (2.) electrocuting black targets with natural host odours. The catch of G. tachinoides from traps was significantly enhanced (~5×) by odour from cattle but not humans. In contrast, catches from electric targets showed inconsistent results. For G. p. gambiensis both human and cattle odour increased (>2×) the trap catch significantly but not the catch from electric targets. For G. p. palpalis, odours from pigs and humans increased (~5×) the numbers of tsetse attracted to the vicinity of the odour source but had little effect on landing or trap-entry. For G. tachinoides a blend of POCA (P = 3-n-propylphenol; O = 1-octen-3-ol; C = 4-methylphenol; A = acetone) alone or synthetic cattle odour (acetone, 1-octen-3-ol, 4-methylphenol and 3-n-propylphenol with carbon dioxide) consistently caught more tsetse than natural cattle odour. For G. p. gambiensis, POCA consistently increased catches from both traps and targets. For G. p. palpalis, doses of carbon dioxide similar to those produced by a host resulted in similar increases in attraction. Baiting traps with super-normal (~500 mg/h) doses of acetone also consistently produced significant but slight (~1.6×) increases in catches of male flies. The results suggest that odour-baited traps and insecticide-treated targets could assist the AU-Pan African Tsetse and Trypanosomiasis Eradication Campaign (PATTEC) in its current efforts to monitor and control Palpalis group tsetse in West Africa. For all three species, only ~50% of the flies attracted to the vicinity of the trap were actually caught by it, suggesting that better traps might be developed by an analysis of the visual responses and identification of any semiochemicals involved in short-range interaction

    Vegetation and the importance of insecticide-treated target siting for control of Glossina fuscipes fuscipes

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    Control of tsetse flies using insecticide-treated targets is often hampered by vegetation re-growth and encroachment which obscures a target and renders it less effective. Potentially this is of particular concern for the newly developed small targets (0.25 high × 0.5 m wide) which show promise for cost-efficient control of Palpalis group tsetse flies. Consequently the performance of a small target was investigated for Glossina fuscipes fuscipes in Kenya, when the target was obscured following the placement of vegetation to simulate various degrees of natural bush encroachment. Catches decreased significantly only when the target was obscured by more than 80%. Even if a small target is underneath a very low overhanging bush (0.5 m above ground), the numbers of G. f. fuscipes decreased by only about 30% compared to a target in the open. We show that the efficiency of the small targets, even in small (1 m diameter) clearings, is largely uncompromised by vegetation re-growth because G. f. fuscipes readily enter between and under vegetation. The essential characteristic is that there should be some openings between vegetation. This implies that for this important vector of HAT, and possibly other Palpalis group flies, a smaller initial clearance zone around targets can be made and longer interval between site maintenance visits is possible both of which will result in cost savings for large scale operations. We also investigated and discuss other site features e.g. large solid objects and position in relation to the water's edge in terms of the efficacy of the small targets

    Toward Energetically Autonomous Foraging Soft Robots

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    © 2016, Mary Ann Liebert, Inc. A significant goal of robotics is to develop autonomous machines, capable of independent and collective operation free from human assistance. To operate with complete autonomy robots must be capable of independent movement and total energy self-sufficiency. We present the design of a soft robotic mouth and artificial stomach for aquatic robots that will allow them to feed on biomatter in their surrounding environment. The robot is powered by electrical energy generated through bacterial respiration within a microbial fuel cell (MFC) stomach, and harvested using state-of-the-art voltage step-up electronics. Through innovative exploitation of compliant, biomimetic actuation, the soft robotic feeding mechanism enables the connection of multiple MFC stomachs in series configuration in an aquatic environment, previously a significant challenge. We investigate how a similar soft robotic feeding mechanism could be driven by electroactive polymer artificial muscles from the same bioenergy supply. This work demonstrates the potential for energetically autonomous soft robotic artificial organisms and sets the stage for radically different future robots

    Near-optimal asymmetric binary matrix partitions

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    We study the asymmetric binary matrix partition problem that was recently introduced by Alon et al. (WINE 2013) to model the impact of asymmetric information on the revenue of the seller in take-it-or-leave-it sales. Instances of the problem consist of an n×mn \times m binary matrix AA and a probability distribution over its columns. A partition scheme B=(B1,...,Bn)B=(B_1,...,B_n) consists of a partition BiB_i for each row ii of AA. The partition BiB_i acts as a smoothing operator on row ii that distributes the expected value of each partition subset proportionally to all its entries. Given a scheme BB that induces a smooth matrix ABA^B, the partition value is the expected maximum column entry of ABA^B. The objective is to find a partition scheme such that the resulting partition value is maximized. We present a 9/109/10-approximation algorithm for the case where the probability distribution is uniform and a (11/e)(1-1/e)-approximation algorithm for non-uniform distributions, significantly improving results of Alon et al. Although our first algorithm is combinatorial (and very simple), the analysis is based on linear programming and duality arguments. In our second result we exploit a nice relation of the problem to submodular welfare maximization.Comment: 17 page

    Theory of differential inclusions and its application in mechanics

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    The following chapter deals with systems of differential equations with discontinuous right-hand sides. The key question is how to define the solutions of such systems. The most adequate approach is to treat discontinuous systems as systems with multivalued right-hand sides (differential inclusions). In this work three well-known definitions of solution of discontinuous system are considered. We will demonstrate the difference between these definitions and their application to different mechanical problems. Mathematical models of drilling systems with discontinuous friction torque characteristics are considered. Here, opposite to classical Coulomb symmetric friction law, the friction torque characteristic is asymmetrical. Problem of sudden load change is studied. Analytical methods of investigation of systems with such asymmetrical friction based on the use of Lyapunov functions are demonstrated. The Watt governor and Chua system are considered to show different aspects of computer modeling of discontinuous systems
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