93,051 research outputs found
Dynamic Occupancy Grid Prediction for Urban Autonomous Driving: A Deep Learning Approach with Fully Automatic Labeling
Long-term situation prediction plays a crucial role in the development of
intelligent vehicles. A major challenge still to overcome is the prediction of
complex downtown scenarios with multiple road users, e.g., pedestrians, bikes,
and motor vehicles, interacting with each other. This contribution tackles this
challenge by combining a Bayesian filtering technique for environment
representation, and machine learning as long-term predictor. More specifically,
a dynamic occupancy grid map is utilized as input to a deep convolutional
neural network. This yields the advantage of using spatially distributed
velocity estimates from a single time step for prediction, rather than a raw
data sequence, alleviating common problems dealing with input time series of
multiple sensors. Furthermore, convolutional neural networks have the inherent
characteristic of using context information, enabling the implicit modeling of
road user interaction. Pixel-wise balancing is applied in the loss function
counteracting the extreme imbalance between static and dynamic cells. One of
the major advantages is the unsupervised learning character due to fully
automatic label generation. The presented algorithm is trained and evaluated on
multiple hours of recorded sensor data and compared to Monte-Carlo simulation
The Distance and Morphology of V723 Cassiopeiae (NOVA CASSIOPEIA 1995)
We present spatially resolved infrared spectra of V723 Cas (Nova Cassiopeia
1995) obtained over four years with the integral field spectrograph OSIRIS on
Keck II. Also presented are one epoch of spatially unresolved spectra from the
long slit spectrograph NIRSPEC on Keck II. The OSIRIS observations made use of
the laser guide star adaptive optics facility that produced diffraction-limited
spatial resolution of the strong coronal emission features in the nova ejecta.
We remove the point-like continuum from V723 Cas data cubes to reveal details
of the extended nebula and find that emission due to [Si VI] and [Ca VIII] has
an equatorial ring structure with polar nodules-a strikingly different
morphology than emission due to [Al IX], which appears as a prolate spheroid.
The contrast in structure may indicate separate ejection events. Using the
angular expansion and Doppler velocities observed over four epochs spaced at
one year intervals, we determine the distance to V723 Cas to be 3.85+0.23-0.21
kpc. We present the OSIRIS three-dimensional data here in many ways: as
narrowband images, one- and two-dimensional spectra, and a volume rendering
that reveals the true shape of the ejecta.Comment: 37 pages, 8 figure
A survey on Human Mobility and its applications
Human Mobility has attracted attentions from different fields of studies such
as epidemic modeling, traffic engineering, traffic prediction and urban
planning. In this survey we review major characteristics of human mobility
studies including from trajectory-based studies to studies using graph and
network theory. In trajectory-based studies statistical measures such as jump
length distribution and radius of gyration are analyzed in order to investigate
how people move in their daily life, and if it is possible to model this
individual movements and make prediction based on them. Using graph in mobility
studies, helps to investigate the dynamic behavior of the system, such as
diffusion and flow in the network and makes it easier to estimate how much one
part of the network influences another by using metrics like centrality
measures. We aim to study population flow in transportation networks using
mobility data to derive models and patterns, and to develop new applications in
predicting phenomena such as congestion. Human Mobility studies with the new
generation of mobility data provided by cellular phone networks, arise new
challenges such as data storing, data representation, data analysis and
computation complexity. A comparative review of different data types used in
current tools and applications of Human Mobility studies leads us to new
approaches for dealing with mentioned challenges
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