8,600 research outputs found

    Mobile Robots for Localizing Gas Emission Sources on Landfill Sites: Is Bio-Inspiration the Way to Go?

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    Roboticists often take inspiration from animals for designing sensors, actuators, or algorithms that control the behavior of robots. Bio-inspiration is motivated with the uncanny ability of animals to solve complex tasks like recognizing and manipulating objects, walking on uneven terrains, or navigating to the source of an odor plume. In particular the task of tracking an odor plume up to its source has nearly exclusively been addressed using biologically inspired algorithms and robots have been developed, for example, to mimic the behavior of moths, dung beetles, or lobsters. In this paper we argue that biomimetic approaches to gas source localization are of limited use, primarily because animals differ fundamentally in their sensing and actuation capabilities from state-of-the-art gas-sensitive mobile robots. To support our claim, we compare actuation and chemical sensing available to mobile robots to the corresponding capabilities of moths. We further characterize airflow and chemosensor measurements obtained with three different robot platforms (two wheeled robots and one flying micro-drone) in four prototypical environments and show that the assumption of a constant and unidirectional airflow, which is the basis of many gas source localization approaches, is usually far from being valid. This analysis should help to identify how underlying principles, which govern the gas source tracking behavior of animals, can be usefully “translated” into gas source localization approaches that fully take into account the capabilities of mobile robots. We also describe the requirements for a reference application, monitoring of gas emissions at landfill sites with mobile robots, and discuss an engineered gas source localization approach based on statistics as an alternative to biologically inspired algorithms

    DeepToF: Off-the-shelf real-time correction of multipath interference in time-of-flight imaging

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    Time-of-flight (ToF) imaging has become a widespread technique for depth estimation, allowing affordable off-the-shelf cameras to provide depth maps in real time. However, multipath interference (MPI) resulting from indirect illumination significantly degrades the captured depth. Most previous works have tried to solve this problem by means of complex hardware modifications or costly computations. In this work, we avoid these approaches and propose a new technique to correct errors in depth caused by MPI, which requires no camera modifications and takes just 10 milliseconds per frame. Our observations about the nature of MPI suggest that most of its information is available in image space; this allows us to formulate the depth imaging process as a spatially-varying convolution and use a convolutional neural network to correct MPI errors. Since the input and output data present similar structure, we base our network on an autoencoder, which we train in two stages. First, we use the encoder (convolution filters) to learn a suitable basis to represent MPI-corrupted depth images; then, we train the decoder (deconvolution filters) to correct depth from synthetic scenes, generated by using a physically-based, time-resolved renderer. This approach allows us to tackle a key problem in ToF, the lack of ground-truth data, by using a large-scale captured training set with MPI-corrupted depth to train the encoder, and a smaller synthetic training set with ground truth depth to train the decoder stage of the network. We demonstrate and validate our method on both synthetic and real complex scenarios, using an off-the-shelf ToF camera, and with only the captured, incorrect depth as input

    End-to-end Security for Connected Vehicles

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    Recently Mode 4 operation of Cellular Vehicle to Everything (C-V2X) specifies the operation of vehicle-to-vehicle, vehicle-to-pedestrian and vehicle-to-UE-stationary over the PC5 interface. However, the security is delegated to the application layer, which is out of the scope of the 3GPP-layer specification. Hence, we propose a transparent and independent distributed security protocol for C-V2X over the PC5 interface at the RLC-layer based on cryptographic ratchets. Our new proposed security protocol provides authenticated encryption, integrity, forward and backward secrecy. The security procedure can start on the fly as soon as vehicles enter a C-V2X group over the PC5 interface, using the cryptographic credentials of the digital certificate issued for ITS applications. The distributed security protocol supports strong encryption, authentication and privacy regardless of the use case in 5G applications for C-V2X over the PC5 interface.12th International Workshop on Information Network Design (WIND-2020), in conjunction with 12th International Conference on Intelligent Networking and Collaborative Systems (INCoS-2020), August 31st - September 2nd, 2020, University of Victoria, Canada(新型コロナ感染拡大に伴い、現地開催中止

    Gallic acid production with mouldy polyurethane particles obtained from solid state culture of Aspergillus niger GH1

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    Gallic acid production in a batch bioreactor was evaluated using as catalytic material the mouldy polyurethane solids (MPS) obtained from a solid-state fermentation (SSF) bioprocess carried out for tannase production by Aspergillus niger GH1 on polyurethane foam powder (PUF) with 5 % (v/w) of tannic acid as inducer. Fungal biomass, tannic acid consumption and tannase production were kinetically monitored. SSF was stopped when tannase activity reached its maximum level. Effects of washing with distilled water and drying on the tannase activity of MPS were determined. Better results were obtained with dried and washed MPS retaining 84 % of the tannase activity. Maximum tannase activity produced through SSF after 24 h of incubation was equivalent to 130 U/gS with a specific activity of 36 U/mg. The methylgallate was hydrolysed (45 %) in an easy, cheap and fast bioprocess (30 min). Kinetic parameters of tannase self-immobilized on polyurethane particles were calculated to be 5 mM and 04.1×102 mM/min for K M and V max, respectively. Results demonstrated that the MPS, with tannase activity, can be successfully used for the production of the antioxidant gallic acid from methyl-gallate substrate. Direct use of PMS to produce gallic acid can be advantageous as no previous extraction of enzyme is required, thus reducing production costs.Authors thank the National Council for Science and Technology (CONACYT-Mexico) for the financial support. The present work was performed as part of a cooperative agreement between DIA-Universidad Autonoma de Coahuila (Mexico) and IBB-Universidade do Minho (Portugal) within a specific training stay undertaken at the DEB-UM. Part of the research was funded by a project SEP-CONACYT-CB-2011

    Prototyping of petalets for the Phase-II Upgrade of the silicon strip tracking detector of the ATLAS Experiment

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    In the high luminosity era of the Large Hadron Collider, the HL-LHC, the instantaneous luminosity is expected to reach unprecedented values, resulting in about 200 proton-proton interactions in a typical bunch crossing. To cope with the resultant increase in occupancy, bandwidth and radiation damage, the ATLAS Inner Detector will be replaced by an all-silicon system, the Inner Tracker (ITk). The ITk consists of a silicon pixel and a strip detector and exploits the concept of modularity. Prototyping and testing of various strip detector components has been carried out. This paper presents the developments and results obtained with reduced-size structures equivalent to those foreseen to be used in the forward region of the silicon strip detector. Referred to as petalets, these structures are built around a composite sandwich with embedded cooling pipes and electrical tapes for routing the signals and power. Detector modules built using electronic flex boards and silicon strip sensors are glued on both the front and back side surfaces of the carbon structure. Details are given on the assembly, testing and evaluation of several petalets. Measurement results of both mechanical and electrical quantities are shown. Moreover, an outlook is given for improved prototyping plans for large structures.Comment: 22 pages for submission for Journal of Instrumentatio

    Diversity and Strain Specificity of Plant Cell Wall Degrading Enzymes Revealed by the Draft Genome of Ruminococcus flavefaciens FD-1

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    Ruminococcus flavefaciens is a predominant cellulolytic rumen bacterium, which forms a multi-enzyme cellulosome complex that could play an integral role in the ability of this bacterium to degrade plant cell wall polysaccharides. Identifying the major enzyme types involved in plant cell wall degradation is essential for gaining a better understanding of the cellulolytic capabilities of this organism as well as highlighting potential enzymes for application in improvement of livestock nutrition and for conversion of cellulosic biomass to liquid fuels

    Effect of lipid-lowering treatment in cardiovascular disease prevalence in familial hypercholesterolemia

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    Background and aims: The impact on heterozygous familial hypercholesterolemia (HeFH) health led by high-intensity lipid-lowering therapy (HILLT) is unknown, and the question remains if there is still an unacceptably high residual risk to justify treatment with new lipid-lowering drugs. Methods: This observational, retrospective, multicenter, national study in Spain, whose information was obtained from a national dyslipemia registry, was designed to establish the current prevalence of cardiovascular disease (CVD) in HeFH and to define the impact of HILLT on CVD in this population. Odds were estimated using several logistic regression models with progressive adjustment. Results: 1958 HeFH, mean age 49.3 ± 14.3 years, were included in the analysis. At inclusion in the registry, 295 patients (15.1%) had suffered CVD and 164 (55.6%) had suffered the first event before the onset lipid-lowering treatment. Exposition to treatment associated more than ten times lower odds for CVD than in subjects naïve to treatment (OR 0.085, 95% CI 0.063–0.114, p < 0.001). A first CVD event after a mean treatment period of 9.1 ± 7.2 years occurred in 131 out of 1615 (8.1%) HeFH subjects, and 115 (87.8%) of them were on HILLT. Conclusions: Current prevalence of CVD among HeFH is one third of that reported before the statins era. Early initiation and prolonged lipid-lowering treatment was associated with a reduction in CVD. New cases of CVD, in spite of HILLT, appeared mostly among patients accumulating risk factors and probably they may be considered for further lipid-lowering drugs

    Circulating cardiac troponin I levels measured by a novel highly sensitive assay in acute decompensated heart failure: insights from the ASCEND-HF trial

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    Background: Circulating cardiac troponin levels (cTn), representative of myocardial injury, are commonly elevated in heart failure (HF) and related to adverse clinical events. However, whether cTn represents a spectrum of risk in HF is unclear. Methods: Baseline, 48–72 hour, and 30 day plasma cTnI was measured by a novel highly-sensitive assay in 900 subjects with acute decompensated HF (ADHF) in ASCEND-HF. Multivariable models determined the relationship between cTnI and outcomes. Results: The median(interquartile range) cTnI was 16.4 (9.3-31.6) ng/L at baseline, 14.1 (7.8-29.7) ng/L at 48-72 hours, and 11.6 (6.8-22.5) ng/L at 30 days. After additional adjustment for amino terminal pro-B-type natriuretic peptide (NT-proBNP) to established risk predictors, both baseline and 48-72 hour cTnI were associated with higher risk for death or worsening HF prior to discharge (OR 1.25, P=0.03 and OR 1.43, P=0.001, respectively). However, only cTnI at 30 days was associated 180-day death (HR 1.25, P=0.007). There were no curvilinear associations between changing cTnI and clinical outcomes. Conclusions: Circulating cTnI level was associated with clinical outcomes in ADHF, but these observations diminished with additional adjustment for NT-proBNP. Although they likely represent a spectrum of risk in ADHF, these findings question the implications of changing cTnI levels during treatment
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