34,948 research outputs found
Beam test results of 3D fine-grained scintillator detector prototype for a T2K ND280 neutrino active target
An upgrade of the long baseline neutrino experiment T2K near detector ND280
is currently being developed with the goal to reduce systematic uncertainties
in the prediction of number of events at the far detector Super-Kamiokande. The
upgrade program includes the design and construction of a new highly granular
fully active scintillator detector with 3D WLS fiber readout as a neutrino
target. The detector of about in size and a mass
of 2.2~tons will be assembled from about plastic
scintillator cubes of . Each cube is read out by three
orthogonal Kuraray Y11 Wave Length Shifting (WLS) fibers threaded through the
detector. A detector prototype made of 125 cubes was assembled and tested in a
charged particle test beam at CERN in the fall of 2017. This paper presents the
results obtained on the light yield and timing as well as on the optical
cross-talk between the cubes.Comment: 5 pages, 8 figure
ShapeStacks: Learning Vision-Based Physical Intuition for Generalised Object Stacking
Physical intuition is pivotal for intelligent agents to perform complex
tasks. In this paper we investigate the passive acquisition of an intuitive
understanding of physical principles as well as the active utilisation of this
intuition in the context of generalised object stacking. To this end, we
provide: a simulation-based dataset featuring 20,000 stack configurations
composed of a variety of elementary geometric primitives richly annotated
regarding semantics and structural stability. We train visual classifiers for
binary stability prediction on the ShapeStacks data and scrutinise their
learned physical intuition. Due to the richness of the training data our
approach also generalises favourably to real-world scenarios achieving
state-of-the-art stability prediction on a publicly available benchmark of
block towers. We then leverage the physical intuition learned by our model to
actively construct stable stacks and observe the emergence of an intuitive
notion of stackability - an inherent object affordance - induced by the active
stacking task. Our approach performs well even in challenging conditions where
it considerably exceeds the stack height observed during training or in cases
where initially unstable structures must be stabilised via counterbalancing.Comment: revised version to appear at ECCV 201
Realtime Profiling of Fine-Grained Air Quality Index Distribution using UAV Sensing
Given significant air pollution problems, air quality index (AQI) monitoring
has recently received increasing attention. In this paper, we design a mobile
AQI monitoring system boarded on unmanned-aerial-vehicles (UAVs), called ARMS,
to efficiently build fine-grained AQI maps in realtime. Specifically, we first
propose the Gaussian plume model on basis of the neural network (GPM-NN), to
physically characterize the particle dispersion in the air. Based on GPM-NN, we
propose a battery efficient and adaptive monitoring algorithm to monitor AQI at
the selected locations and construct an accurate AQI map with the sensed data.
The proposed adaptive monitoring algorithm is evaluated in two typical
scenarios, a two-dimensional open space like a roadside park, and a
three-dimensional space like a courtyard inside a building. Experimental
results demonstrate that our system can provide higher prediction accuracy of
AQI with GPM-NN than other existing models, while greatly reducing the power
consumption with the adaptive monitoring algorithm
Counting-on, trading and partitioning: effects of training and prior knowledge on performance on Base-10 tasks
Factors affecting performance on Base-10 tasks were investigated in a series of four studies with a total of 453 children aged five to seven years. Training in counting-on was found to enhance child performance on Base-10 tasks (Studies 2, 3, and 4), while prior knowledge of counting-on (Study 1), trading (Studies 1 and 3) and partitioning (Studies 1 and 4) were associated with enhanced Base-10 performance. It emerged that procedural knowledge of counting-on, trading and partitioning can lead to improvements in procedural knowledge of the Base-10 system. The findings lend support to the model of iterative development of conceptual and procedural knowledge advanced by Rittle-Johnson, Siegler and Alibali (2001)
Laser geodynamic satellite thermal/optical/vibrational analysis and testing, volume 2, book 2
The main tasks described involved an interferometric evaluation of several cubes, a prediction of their dihedral angles, a comparison of these predictions with independent measurements, a prediction and comparison of far field performance, recommendations as to revised dihedral angles and a subsequent analysis of cubes which were reworked to confirm the recommendations. A tolerance study and theoretical evaluation of several cubes was also performed to aid in understanding the results. The far field characteristics evaluated included polarization effects and treated both intensity distribution and encircled energy data. The energy in the 13.2 - 16.9 arc-sec annular region was tabulated as an indicator of performance sensitivity. The results are provided in viewgraph form, and show the average dihedral angle of an original set of test cubes to have been 1.8 arc-sec with an average far field annulus diameter of 18 arc-sec. Since the peak energy in the 13.2 - 16.9 arc-sec annulus was found to occur for a 1.35 arc-sec cube, and since cube tolerances were shown to increase the annulus diameter slightly, a nominal dihedral angle of 1.25 arc-sec was recommended
Free Minimization of the Fundamental Measure Theory Functional: Freezing of Parallel Hard Squares and Cubes
Due to remarkable advances in colloid synthesis techniques, systems of
squares and cubes, once an academic abstraction for theorists and simulators,
are nowadays an experimental reality. By means of a free minimization of the
free-energy functional, we apply Fundamental Measure Theory to analyze the
phase behavior of parallel hard squares and hard cubes. We compare our results
with those obtained by the traditional approach based on the Gaussian
parameterization, finding small deviations and good overall agreement between
the two methods. For hard squares our predictions feature at intermediate
packing fraction a smectic phase, which is however expected to be unstable due
to thermal fluctuations. This implies that for hard squares the theory predicts
either a vacancy-rich second-order transition or a vacancy-poor weakly
first-order phase transition at higher density. In accordance with previous
studies, a second-order transition with a high vacancy concentration is
predicted for hard cubes
On the use of fractional Brownian motion simulations to determine the 3D statistical properties of interstellar gas
Based on fractional Brownian motion (fBm) simulations of 3D gas density and
velocity fields, we present a study of the statistical properties of
spectro-imagery observations (channel maps, integrated emission, and line
centroid velocity) in the case of an optically thin medium at various
temperatures. The power spectral index gamma_W of the integrated emission is
identified with that of the 3D density field (gamma_n) provided the medium's
depth is at least of the order of the largest transverse scale in the image,
and the power spectrum of the centroid velocity map is found to have the same
index gamma_C as that of the velocity field (gamma_v). Further tests with
non-fBm density and velocity fields show that this last result holds, and is
not modified either by the effects of density-velocity correlations. A
comparison is made with the theoretical predictions of Lazarian & Pogosyan
(2000).Comment: 28 pages, 14 figures, accepted for publication in ApJ. For preprint
with higher-resolution figures, see
http://www.cita.utoronto.ca/~mamd/miville_fbm2003.pd
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