23,736 research outputs found
A Deep Learning Approach to Drone Monitoring
A drone monitoring system that integrates deep-learning-based detection and
tracking modules is proposed in this work. The biggest challenge in adopting
deep learning methods for drone detection is the limited amount of training
drone images. To address this issue, we develop a model-based drone
augmentation technique that automatically generates drone images with a
bounding box label on drone's location. To track a small flying drone, we
utilize the residual information between consecutive image frames. Finally, we
present an integrated detection and tracking system that outperforms the
performance of each individual module containing detection or tracking only.
The experiments show that, even being trained on synthetic data, the proposed
system performs well on real world drone images with complex background. The
USC drone detection and tracking dataset with user labeled bounding boxes is
available to the public
Carbon Trading with Blockchain
Blockchain has the potential to accelerate the deployment of emissions
trading systems (ETS) worldwide and improve upon the efficiency of existing
systems. In this paper, we present a model for a permissioned blockchain
implementation based on the successful European Union (EU) ETS and discuss its
potential advantages over existing technology. We propose an ETS model that is
both backwards compatible and future-proof, characterised by
interconnectedness, transparency, tamper-resistance and high liquidity.
Further, we identify key challenges to implementation of a blockchain ETS, as
well as areas of future work required to enable a fully-decentralised
blockchain ETS
Joint Scheduling and Resource Allocation in the OFDMA Downlink: Utility Maximization under Imperfect Channel-State Information
We consider the problem of simultaneous user-scheduling, power-allocation,
and rate-selection in an OFDMA downlink, with the goal of maximizing expected
sum-utility under a sum-power constraint. In doing so, we consider a family of
generic goodput-based utilities that facilitate, e.g., throughput-based
pricing, quality-of-service enforcement, and/or the treatment of practical
modulation-and-coding schemes (MCS). Since perfect knowledge of channel state
information (CSI) may be difficult to maintain at the base-station, especially
when the number of users and/or subchannels is large, we consider scheduling
and resource allocation under imperfect CSI, where the channel state is
described by a generic probability distribution. First, we consider the
"continuous" case where multiple users and/or code rates can time-share a
single OFDMA subchannel and time slot. This yields a non-convex optimization
problem that we convert into a convex optimization problem and solve exactly
using a dual optimization approach. Second, we consider the "discrete" case
where only a single user and code rate is allowed per OFDMA subchannel per time
slot. For the mixed-integer optimization problem that arises, we discuss the
connections it has with the continuous case and show that it can solved exactly
in some situations. For the other situations, we present a bound on the
optimality gap. For both cases, we provide algorithmic implementations of the
obtained solution. Finally, we study, numerically, the performance of the
proposed algorithms under various degrees of CSI uncertainty, utilities, and
OFDMA system configurations. In addition, we demonstrate advantages relative to
existing state-of-the-art algorithms
Centrality dependence of the multiplicity and transverse momentum distributions at RHIC and LHC and the percolation of strings
The dependence of the multiplicity and the transverse momentum distribution
on the number of collisions are studied for central and peripheral Au-Au
collisions at SPS, RHIC and LHC energies in the framework of percolation of
strings. A scaling law relating the multiplicity to the mean transverse
momentum is obtained. Our results are in overall agreement with the SPS and
RHIC data, obtaining a suppression on distribution even for larger
than 1 GeV/c.Comment: Contribution to QM2002, espcrc1.st
Studies in matter antimatter separation and in the origin of lunar magnetism
Antimatter experiments of the University of Santa Clara are investigated. Topics reported include: (1) planetary geology, (2) lunar Apollo magnetometer experiments, and (3) Roche limit of a solid body
Event-by-Event Search for Charged Neutral Fluctuations in Pb - Pb Collisions at 158-A-GeV
Results from the analysis of data obtained from the WA98 experiment at the
CERN SPS have been presented. Some events have been filtered which show photon
excess in limited zones within the overlap region of the charged
particle and photon multiplicity detectors.Comment: 6 pages, 4 figure
Interferometry of direct photons in Pb+Pb collisions at 158 AGeV
We present final results from the WA98 experiment which provide first
measurements of Bose-Einstein correlations of direct photons in
ultrarelativistic heavy ion collisions. Invariant interferometric radii were
extracted in the range MeV/c and compared to interferometric
radii of charged pions. The yield of direct photons for MeV/c was
extracted from the correlation strength parameter and compared to the yield of
direct photons measured in WA98 at higher with the statistical
subtraction method, and to predictions of a fireball model.Comment: 4 pages, 3 figures, proceedings for Quark Matter 200
Investigation of high p events in Nucleus-Nucleus collisions using the Hijing event generator
In recent years lot of interest has been observed in the nucleus-nucleus
collisions at RHIC energies in phenomena related to high physics
\cite{ref1}. The suppression of high particles and disappearance of
back-to-back jets compared to the scaling with number of binary nucleon-nucleon
collisions indicates that a nearly perfect liquid is produced in these
collisions. Results on self shadowing of high events are presented
using hadron multiplicity associated to high and unbiased events in
nucleus-nucleus collisions \cite{ref2} obtained from the hijing event
generator.Comment: 4 pages, 3 figures, Proceedings of the poster presented at Quark
Matter 200
Change detection in categorical evolving data streams
Detecting change in evolving data streams is a central issue for accurate adaptive learning. In real world applications, data streams have categorical features, and changes induced in the data distribution of these categorical features have not been considered extensively so far. Previous work on change detection focused on detecting changes in the accuracy of the learners, but without considering changes in the data distribution.
To cope with these issues, we propose a new unsupervised change detection method, called CDCStream (Change Detection in Categorical Data Streams), well suited for categorical data streams. The proposed method is able to detect changes in a batch incremental scenario. It is based on the two following characteristics: (i) a summarization strategy is proposed to compress the actual batch by extracting a descriptive summary and (ii) a new segmentation algorithm is proposed to highlight changes and issue warnings for a data stream. To evaluate our proposal we employ it in a learning task over real world data and we compare its results with state of the art methods. We also report qualitative evaluation in order to show the behavior of CDCStream
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