Auto-correction of 3D-orientation of IMUs on electric bicycles

The application of inertial measurement units (IMU) in electronically power-assisted cycles (EPACs) has become increasingly important for improving their functionalities. One central issue of such an application is to calibrate the orientation of the IMU on the EPAC. The approach presented in this paper utilizes common bicycling motions to calibrate the 2D- and 3D-mounting orientation of a micro-electro-mechanical system (MEMS) IMU on an electric bicycle. The method is independent of sensor biases and requires only a very low computation expense and, thus, the estimation can be realized in real-time. In addition, the acceleration biases are estimated using a barometric pressure sensor. The experimental results show high accuracy of the calibrated orientation and estimated sensor biases

Active topolectrical circuits

The transfer of topological concepts from the quantum world to classical mechanical and electronic systems has opened fundamentally new approaches to protected information transmission and wave guidance. A particularly promising technology are recently discovered topolectrical circuits that achieve robust electric signal transduction by mimicking edge currents in quantum Hall systems. In parallel, modern active matter research has shown how autonomous units driven by internal energy reservoirs can spontaneously self-organize into collective coherent dynamics. Here, we unify key ideas from these two previously disparate fields to develop design principles for active topolectrical circuits (ATCs) that can self-excite topologically protected global signal patterns. Realizing autonomous active units through nonlinear Chua diode circuits, we theoretically predict and experimentally confirm the emergence of self-organized protected edge oscillations in one- and two-dimensional ATCs. The close agreement between theory, simulations and experiments implies that nonlinear ATCs provide a robust and versatile platform for developing high-dimensional autonomous electrical circuits with topologically protected functionalities.Comment: 10 pages, 4 figures, includes supplementary material. This version adds 2D experiment

Heat source localisation by trilateration of helium II second sound detected with transition edge sensors thermometry

The detection of second sound in He-II can be exploited during superconducting cavity testing to locate the germ of a quench. The sudden appearance of a hotspot generates this wave in the helium II bath, which is routinely detected by Oscillating Superleak Transducers (OST) reacting to the first arrived inter-component velocity front. Recently, we have developed Transition Edge Sensors (TES) that are able to detect second sound by measuring directly the temperature fluctuation of second sound (below milli-Kelvin, in sub-millisecond time scale) with a good native signal-to-noise ratio. We present the current state of development of second sound detectors based on TES, experiments aiming to characterize more thoroughly their behaviour as second sound detectors by thermometry, and the capabilities they provide in terms of localisation of the heat source in the case of direct sight

Realizing efficient topological temporal pumping in electrical circuits

Quantized adiabatic transport can occur when a system is slowly modulated over time. In most realizations however, the efficiency of such transport is reduced by unwanted dissipation, back-scattering, and non-adiabatic effects. In this work, we realize a topological adiabatic pump in an electrical circuit network that supports remarkably stable and long-lasting pumping of a voltage signal. We further characterize the topology of our system by deducing the Chern number from the measured edge band structure. To achieve this, the experimental setup makes use of active circuit elements that act as time-variable voltage-controlled inductors.Comment: main (5 pages, 3 figures) plus supplement (8 pages, 4 figures

Simulating hyperbolic space on a circuit board

The Laplace operator encodes the behavior of physical systems at vastly different scales, describing heat flow, fluids, as well as electric, gravitational, and quantum fields. A key input for the Laplace equation is the curvature of space. Here we discuss and experimentally demonstrate that the spectral ordering of Laplacian eigenstates for hyperbolic (negatively curved) and flat two-dimensional spaces has a universally different structure. We use a lattice regularization of hyperbolic space in an electric-circuit network to measure the eigenstates of a ‘hyperbolic drum’, and in a time-resolved experiment we verify signal propagation along the curved geodesics. Our experiments showcase both a versatile platform to emulate hyperbolic lattices in tabletop experiments, and a set of methods to verify the effective hyperbolic metric in this and other platforms. The presented techniques can be utilized to explore novel aspects of both classical and quantum dynamics in negatively curved spaces, and to realise the emerging models of topological hyperbolic matter

Unified access to media metadata on the web: Towards interoperability using a core vocabulary.

The goal of the W3C's Media Annotation Working Group (MAWG) is to promote interoperability between multimedia metadata formats on the Web. As experienced by everybody, audiovisual data is omnipresent on today's Web. However, different interaction interfaces and especially diverse metadata formats prevent unified search, access, and navigation. MAWG has addressed this issue by developing an interlingua ontology and an associated API. This article discusses the rationale and core concepts of the ontology and API for media resources. The specifications developed by MAWG enable interoperable contextualized and semantic annotation and search, independent of the source metadata format, and connecting multimedia data to the Linked Data cloud. Some demonstrators of such applications are also presented in this article

Germline variation at 8q24 and prostate cancer risk in men of European ancestry

Chromosome 8q24 is a susceptibility locus for multiple cancers, including prostate cancer. Here we combine genetic data across the 8q24 susceptibility region from 71,535 prostate cancer cases and 52,935 controls of European ancestry to define the overall contribution of germline variation at 8q24 to prostate cancer risk. We identify 12 independent risk signals for prostate cancer (p < 4.28 × 10−15), including three risk variants that have yet to be reported. From a polygenic risk score (PRS) model, derived to assess the cumulative effect of risk variants at 8q24, men in the top 1% of the PRS have a 4-fold (95%CI = 3.62–4.40) greater risk compared to the population average. These 12 variants account for ~25% of what can be currently explained of the familial risk of prostate cancer by known genetic risk factors. These findings highlight the overwhelming contribution of germline variation at 8q24 on prostate cancer risk which has implications for population risk stratification

Fine-mapping of prostate cancer susceptibility loci in a large meta-analysis identifies candidate causal variants

Prostate cancer is a polygenic disease with a large heritable component. A number of common, low-penetrance prostate cancer risk loci have been identified through GWAS. Here we apply the Bayesian multivariate variable selection algorithm JAM to fine-map 84 prostate cancer susceptibility loci, using summary data from a large European ancestry meta-analysis. We observe evidence for multiple independent signals at 12 regions and 99 risk signals overall. Only 15 original GWAS tag SNPs remain among the catalogue of candidate variants identified; the remainder are replaced by more likely candidates. Biological annotation of our credible set of variants indicates significant enrichment within promoter and enhancer elements, and transcription factor-binding sites, including AR, ERG and FOXA1. In 40 regions at least one variant is colocalised with an eQTL in prostate cancer tissue. The refined set of candidate variants substantially increase the proportion of familial relative risk explained by these known susceptibility regions, which highlights the importance of fine-mapping studies and has implications for clinical risk profiling. © 2018 The Author(s).Prostate cancer is a polygenic disease with a large heritable component. A number of common, low-penetrance prostate cancer risk loci have been identified through GWAS. Here we apply the Bayesian multivariate variable selection algorithm JAM to fine-map 84 prostate cancer susceptibility loci, using summary data from a large European ancestry meta-analysis. We observe evidence for multiple independent signals at 12 regions and 99 risk signals overall. Only 15 original GWAS tag SNPs remain among the catalogue of candidate variants identified; the remainder are replaced by more likely candidates. Biological annotation of our credible set of variants indicates significant enrichment within promoter and enhancer elements, and transcription factor-binding sites, including AR, ERG and FOXA1. In 40 regions at least one variant is colocalised with an eQTL in prostate cancer tissue. The refined set of candidate variants substantially increase the proportion of familial relative risk explained by these known susceptibility regions, which highlights the importance of fine-mapping studies and has implications for clinical risk profiling. © 2018 The Author(s).Peer reviewe

Detection of Second Sound in He-II for Thermal Quench Mapping of Superconducting Radio Frequency Accelerating Cavities

The development of future particle accelerators requires intensive testing of superconducting radio frequency cavities with different sizes and geometries. Non-contact thermometry quench localisation techniques proved to be beneficial for the localisation of surface defects that can originate a quench (sudden loss of superconducting state). These techniques are based on the detection of second sound in helium II. Transition Edge Sensors (TES) are highly sensitive thin film thermometers with fast time response. In the present work, their capability as a thermal quench mapping device for superconducting radio frequency cavities is proven experimentally by detecting second sound waves emitted by SMD heaters in a He-II bath at saturated vapour pressure. A characterisation of the sensors at steady bath temperatures was conducted to calculate the thermal sensitivity. An intense metallurgical study of gold-tin TES with different compositions revealed important relations between the superconducting behaviour and the microstructure of the thin film. It was successfully demonstrated that heat treatment can be used to enhance the superconductivity of the sensors after the manufacturing process if desired. A strategy for optimal biasing of the sensors was developed to maximise the signal-to-noise-ratio of the measured second sound signal. The velocity of second sound at 1.8K could be confirmed and the position of the heaters was successfully localised by trilateration with more than 90% of success. In a dedicated testing setup, the threedimensional propagation of second sound could be investigated in terms of angle and distance between heater and sensor. Especially the influence of the heater size and the detection angle could be studied, which reveals useful information for quench detection tests. Finally, the different nature of TES and Oscillating Superleak Transmitters (OST), another common second sound detector, was investigated experimentally showing that the temperature measurement of the TES is less angle dependent than the detection of the movement of the two components in helium II by the OST

Live-Ticker Supported Sports-Video Annotation Enabling Tactic Analysis

International audienceAutomatic semantic annotation of videos remains an openresearch problem. In the domain of soccer matches, live tickers are freelyavailable on the Internet. These tickers can be used as sources of informationabout the events of a soccer match: as they are written by humans,they contain semantic information. This work presents a prototype thatprocesses live ticker texts and transforms them into machine-readable annotations.The prototype produces semantic annotated actions as RDFgraphs.The resulting annotation may be used for other purposes, suchas tactical analysis of the match, semantic multimedia query processingor assistance to other video annotation tools