59 research outputs found
Difficulty Classification of Mountainbike Downhill Trails utilizing Deep Neural Networks
The difficulty of mountainbike downhill trails is a subjective perception.
However, sports-associations and mountainbike park operators attempt to group
trails into different levels of difficulty with scales like the
Singletrail-Skala (S0-S5) or colored scales (blue, red, black, ...) as proposed
by The International Mountain Bicycling Association. Inconsistencies in
difficulty grading occur due to the various scales, different people grading
the trails, differences in topography, and more. We propose an end-to-end deep
learning approach to classify trails into three difficulties easy, medium, and
hard by using sensor data. With mbientlab Meta Motion r0.2 sensor units, we
record accelerometer- and gyroscope data of one rider on multiple trail
segments. A 2D convolutional neural network is trained with a stacked and
concatenated representation of the aforementioned data as its input. We run
experiments with five different sample- and five different kernel sizes and
achieve a maximum Sparse Categorical Accuracy of 0.9097. To the best of our
knowledge, this is the first work targeting computational difficulty
classification of mountainbike downhill trails.Comment: 11 pages, 5 figure
Programmable quantum simulation of 2D antiferromagnets with hundreds of Rydberg atoms
Quantum simulation using synthetic systems is a promising route to solve
outstanding quantum many-body problems in regimes where other approaches,
including numerical ones, fail. Many platforms are being developed towards this
goal, in particular based on trapped ions, superconducting circuits, neutral
atoms or molecules. All of which face two key challenges: (i) scaling up the
ensemble size, whilst retaining high quality control over the parameters and
(ii) certifying the outputs for these large systems. Here, we use programmable
arrays of individual atoms trapped in optical tweezers, with interactions
controlled by laser-excitation to Rydberg states to implement an iconic
many-body problem, the antiferromagnetic 2D transverse field Ising model. We
push this platform to an unprecedented regime with up to 196 atoms manipulated
with high fidelity. We probe the antiferromagnetic order by dynamically tuning
the parameters of the Hamiltonian. We illustrate the versatility of our
platform by exploring various system sizes on two qualitatively different
geometries, square and triangular arrays. We obtain good agreement with
numerical calculations up to a computationally feasible size (around 100
particles). This work demonstrates that our platform can be readily used to
address open questions in many-body physics.Comment: Main text: 6 pages, 4 figures. Supplementary information: 10 pages,
16 figure
Incidence and severity of paravalvular aortic regurgitation with multidetector computed tomography nominal area oversizing or undersizing after transcatheter heart valve replacement with the Sapien 3 : a comparison with the Sapien XT.
Objectives : This study sought to compare the influence of the extent of multidetector computed tomography (MDCT) area oversizing on the incidence of paravalvular aortic regurgitation (PAR) between the Sapien 3 and the Sapien XT transcatheter heart valve (THV) to define a new MDCT sizing guideline suitable for the Sapien 3 platform.
Background : The inverse relationship of PAR occurrence and oversizing has been demonstrated for the Sapien XT but the incidence of PAR with comparable oversizing with the Sapien 3 is not known.
Methods : Sixty-one prospectively enrolled patients who underwent transcatheter aortic valve replacement with the Sapien 3 THV were compared with 92 patients who underwent transcatheter aortic valve replacement with the Sapien XT THV. Patients were categorized depending on the degree of MDCT area oversizing percentage: undersizing (below 0%), 0% to 5%, 5% to 10%, and above 10%. The primary endpoint was mild or greater PAR on transthoracic echocardiography.
Results : Mild or greater PAR was present in 19.7% of patients (12 of 61) in the Sapien 3 group and in 54.3% of patients (50 of 92) in the Sapien XT group (p 10% (p for interaction = 0.54). Moderate or severe PAR rates were also lower in the Sapien 3 group than in the Sapien XT group (3.3% vs. 13.0%, p = 0.04). In the Sapien 3 group, a MDCT area oversizing percentage value of =4.17% was identified as the optimal cutoff value to discriminate patients with or without mild or greater PAR.
Conclusions : Our retrospective analysis suggests that the Sapien 3 THV displays significantly lower rates of PAR than does the Sapien XT THV. A lesser degree of MDCT area oversizing may be employed for this new balloon-expandable THV
The impact of trans-catheter aortic valve replacement induced leftbundle branch block on cardiac reverse remodeling
Background Left bundle branch block (LBBB) is common following trans-catheter aortic valve replacement (TAVR) and has been linked to increased mortality, although whether this is related to less favourable cardiac reverse remodeling is unclear. The aim of the study was to investigate the impact of TAVR induced LBBB on cardiac reverse remodeling. Methods 48 patients undergoing TAVR for severe aortic stenosis were evaluated. 24 patients with new LBBB (LBBB-T) following TAVR were matched with 24 patients with a narrow post-procedure QRS (nQRS). Patients underwent cardiovascular magnetic resonance (CMR) prior to and 6 m post-TAVR. Measured cardiac reverse remodeling parameters included left ventricular (LV) size, ejection fraction (LVEF) and global longitudinal strain (GLS). Inter- and intra-ventricular dyssynchrony were determined using time to peak radial strain derived from CMR Feature Tracking. Results In the LBBB-T group there was an increase in QRS duration from 96 ± 14 to 151 ± 12 ms (P < 0.001) leading to inter- and intra-ventricular dyssynchrony (inter: LBBB-T 130 ± 73 vs nQRS 23 ± 86 ms, p < 0.001; intra: LBBB-T 118 ± 103 vs. nQRS 13 ± 106 ms, p = 0.001). Change in indexed LV end-systolic volume (LVESVi), LVEF and GLS was significantly different between the two groups (LVESVi: nQRS -7.9 ± 14.0 vs. LBBB-T -0.6 ± 10.2 ml/m2, p = 0.02, LVEF: nQRS +4.6 ± 7.8 vs LBBB-T -2.1 ± 6.9%, p = 0.002; GLS: nQRS -2.1 ± 3.6 vs. LBBB-T +0.2 ± 3.2%, p = 0.024). There was a significant correlation between change in QRS and change in LVEF (r = -0.434, p = 0.002) and between change in QRS and change in GLS (r = 0.462, p = 0.001). Post-procedure QRS duration was an independent predictor of change in LVEF and GLS at 6 months. Conclusion TAVR-induced LBBB is associated with less favourable cardiac reverse remodeling at medium term follow up. In view of this, every effort should be made to prevent TAVR-induced LBBB, especially as TAVR is now being extended to a younger, lower risk population
3D-Navigation und Projektion in der Leberchirurgie - Ergebnisse einer Pilotstudie
In this work culture-specific and cross-cultural influences on frequency of use of media and trust in media for B-2-B communication purposes were explored, taking Brazil and Germany as exemplary countries. Using an online survey, 236 respondents from Brazil and Germany were examined regarding their professional media usage. Findings show both culture-specific as well as cultural insensitive media usage in B-2-B communication. Brazilians use new media more frequently than Germans. However, it was also revealed that cross-cultural variables as age, gender and technical self-efficacy influence even more significantly the frequency of use of media. Furthermore, trust in media for B-2-B communication showed to positively correlated with the frequency of use of media in both countries
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