42 research outputs found

    FDLA: A Novel Frequency Diversity and Link Aggregation Solution for Handover in an Indoor Vehicular VLC Network

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    VLC (VLC) has been introduced as a complementary wireless technology that can be widely used in industrial indoor environments where automated guided vehicles aim to ease and accelerate logistics. Despite its advantages, there is one significant drawback of using an indoor () network that is there is a high handover outage duration. In line-of-sight VLC links, such handovers are frequently due to mobility, shadowing, and obstacles. In this paper, we propose a frequency diversity and link aggregation solution, which is a novel technique in Data link layer to tackle handover challenge in indoor networks. We have developed a small-scale prototype and experimentally evaluated its performance for a variety of scenarios and compared the results with other handover techniques. We also assessed the configuration options in more detail, in particular focusing on different network traffic types and various address resolution protocol intervals. The measurement results demonstrate the advantages of our approach for low-outage duration handovers in. The proposed idea is able to decrease the handover outage duration in a two-dimensional network to about 0.2 s, which is considerably lower compared to previous solutions

    Extracting Trait Data from Digitized Herbarium Specimens Using Deep Convolutional Networks

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    Herbarium collections have been the foundation of taxonomical research for centuries and become increasingly important for related fields such as plant ecology or biogeography. Herbaria worldwide are estimated to include c. 400 million specimens, by inclusion of type specimens cover with few exceptions all known plant taxa (c. 350 000 species) and have a temporal dimension that is reached by only few other botanical data sources. Presently, c. 13.5 million digitized herbarium specimens are available online via institutional websites or aggregating websites like GBIF. We used these specimen images in combination with morphological trait data obtained from TRY and the FLOPO knowledge base in order to train deep convolutional networks to recognize these traits as well as phenological states from specimen images. To improve trait recognition, we expanded our approach to include high resolution scans to enable fine grain feature extraction. Furthermore we analyze differences in recognizability of traits depending on trait group (e.g. leaf traits) or higher taxa. Newly mobilized trait data will be used to improve our trait databases. Our approach is described in detail and performance in the recognition of different traits is analyzed and discussed

    TRY plant trait database – enhanced coverage and open access

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    Plant traits - the morphological, anatomical, physiological, biochemical and phenological characteristics of plants - determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait‐based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits - almost complete coverage for ‘plant growth form’. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait–environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives

    The James Webb Space Telescope Mission

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    Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least 4m4m. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the 6.5m6.5m James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 years, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space Telescope Overview, 29 pages, 4 figure

    Identification of genetic variants associated with Huntington's disease progression: a genome-wide association study

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    Background Huntington's disease is caused by a CAG repeat expansion in the huntingtin gene, HTT. Age at onset has been used as a quantitative phenotype in genetic analysis looking for Huntington's disease modifiers, but is hard to define and not always available. Therefore, we aimed to generate a novel measure of disease progression and to identify genetic markers associated with this progression measure. Methods We generated a progression score on the basis of principal component analysis of prospectively acquired longitudinal changes in motor, cognitive, and imaging measures in the 218 indivduals in the TRACK-HD cohort of Huntington's disease gene mutation carriers (data collected 2008–11). We generated a parallel progression score using data from 1773 previously genotyped participants from the European Huntington's Disease Network REGISTRY study of Huntington's disease mutation carriers (data collected 2003–13). We did a genome-wide association analyses in terms of progression for 216 TRACK-HD participants and 1773 REGISTRY participants, then a meta-analysis of these results was undertaken. Findings Longitudinal motor, cognitive, and imaging scores were correlated with each other in TRACK-HD participants, justifying use of a single, cross-domain measure of disease progression in both studies. The TRACK-HD and REGISTRY progression measures were correlated with each other (r=0·674), and with age at onset (TRACK-HD, r=0·315; REGISTRY, r=0·234). The meta-analysis of progression in TRACK-HD and REGISTRY gave a genome-wide significant signal (p=1·12 × 10−10) on chromosome 5 spanning three genes: MSH3, DHFR, and MTRNR2L2. The genes in this locus were associated with progression in TRACK-HD (MSH3 p=2·94 × 10−8 DHFR p=8·37 × 10−7 MTRNR2L2 p=2·15 × 10−9) and to a lesser extent in REGISTRY (MSH3 p=9·36 × 10−4 DHFR p=8·45 × 10−4 MTRNR2L2 p=1·20 × 10−3). The lead single nucleotide polymorphism (SNP) in TRACK-HD (rs557874766) was genome-wide significant in the meta-analysis (p=1·58 × 10−8), and encodes an aminoacid change (Pro67Ala) in MSH3. In TRACK-HD, each copy of the minor allele at this SNP was associated with a 0·4 units per year (95% CI 0·16–0·66) reduction in the rate of change of the Unified Huntington's Disease Rating Scale (UHDRS) Total Motor Score, and a reduction of 0·12 units per year (95% CI 0·06–0·18) in the rate of change of UHDRS Total Functional Capacity score. These associations remained significant after adjusting for age of onset. Interpretation The multidomain progression measure in TRACK-HD was associated with a functional variant that was genome-wide significant in our meta-analysis. The association in only 216 participants implies that the progression measure is a sensitive reflection of disease burden, that the effect size at this locus is large, or both. Knockout of Msh3 reduces somatic expansion in Huntington's disease mouse models, suggesting this mechanism as an area for future therapeutic investigation

    A forcing fictitious domain/immersed boundary method for super-quadric shape of particulate flow simulation of cementitious material

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    Fictitious domain/immersed boundary method (FD/IBM) has recently been used for particulate flows and complex fluid-solid interaction problems. The advantage of FD/IBM over the body- fitted method is that it substantially simplifies grid generation for immersed geometries, and it is easier to handle moving boundary situations. FD/IBM even allows the use of a stationary and non- deformation background mesh, as well as it reduces the cost of computation by avoiding generation of a body-fitted mesh for each time step. In this work, we develop a new platform to directly simulate super-quadric (SQ) particles in fluid based on a forcing fictitious domain method. Specifically, a super-quadric particle function is used to represent particle with varying shapes and sizes as encountered for concrete and mortar. The immersion of particles in fluid is handled by imposing a rigidity solid body motion in the particle domain, as well as adding a forcing term to the Navier-stokes equation by integral of pressure gradient and particle related velocity over the whole particle domain. Particle shapes are given by changing the super-quadric parameters of SQ equation. Particle motions, which occur during pumping of cementitious material, can be calculated and tracked by solving Newton’s equations of motions using the extended discrete element method (XDEM)[4] while the data of fluid flow properties are obtained by solving the Navier-Stokes equations which govern the fluid phase. Hence, a particle interface resolving solver is developed by coupling XDEM and IBM. We validate our solver by performing flow around particles and free falling of a particle in the channel at different parameters in 2D and 3D. The final objective of this work is to develop a particle-resolved direct numerical simulation platform to predict highly packed fluids with different shapes of particles and over a wide range of particle sizes

    Religionspädagogische Inszenierungen im Konfirmationsunterricht. Zur performativen Qualität religiösen Lernens und Lehrens im Raum der Kirche.

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    Die Konfirmation ist eines der zentralen Rituale Evangelischer Kirchlichkeit. Sie erfreut sich nach wie vor einer hohen Wertschätzung und Evidenz und stellt einen Höhepunkt im familiären wie kirchengemeindlichen Leben dar. Weitaus weniger selbstverständlich ist es um die pädagogische Vorbereitung der Kasualie bestellt. Die Umbenennung des Arbeitsfeldes von Konfirmandenunterricht in Konfirmandenarbeit markiert einen theoretischen wie praktischen Perspektivwechsel. Reflexion und Gestaltung wurden um empirisch-sozialwissenschaftliche Einsichten sowie Formen der Sozial- bzw. Gemeindepädagogik erweitert. Gleichwohl fehlt eine integrierende didaktische Theorie, die den Bildungsanlass Konfirmation unter bildungstheoretischen Gesichtspunkten bedenkt und orientiert. In diesem Zusammenhang erschließt die vorliegende Arbeit ein bisher unbearbeitetes Forschungsfeld: die qualitative Analyse didaktischer Prozesse im Rahmen der Konfirmandenarbeit. Bereitgestellt wird einerseits ein methodologisch-methodisches Instrumentarium zur Erkundung von Unterrichtsverläufen. Es wird einsichtig gemacht, wie einzelne Inszenierungen bestimmte Schwerpunkte des Religionssystems herausstellen und als heimlicher Lehrplan funktionieren. Vorgeschlagen wird eine modale Analyse zur Interpretation und Orientierung katechetischen Handelns. Dabei zeigt sich nicht zuletzt, dass und wie religionspädagogische Inszenierungen das Ziel religiöser Bildung unterlaufen bzw. konterkarieren können. Im Umkehrschluss wird eine konstruktive Bestimmung und Balance von Schwerpunkten möglich. Es handelt sich bei dieser Arbeit um Grundlagenforschung, so dass didaktisch-praktische wie normative Konsequenzen nur indirekt abzuleiten sind. Die dargestellten Einsichten können jedoch weitere Forschungsprozesse inspirieren, sie können in pragmatischer Aufnahme sowohl für Ausbildungs- als auch Fortbildungszwecke nutzbar gemacht werden
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