1,725 research outputs found
The Drift Chambers Of The Nomad Experiment
We present a detailed description of the drift chambers used as an active
target and a tracking device in the NOMAD experiment at CERN. The main
characteristics of these chambers are a large area, a self supporting structure
made of light composite materials and a low cost. A spatial resolution of 150
microns has been achieved with a single hit efficiency of 97%.Comment: 42 pages, 26 figure
Visual motion processing and human tracking behavior
The accurate visual tracking of a moving object is a human fundamental skill
that allows to reduce the relative slip and instability of the object's image
on the retina, thus granting a stable, high-quality vision. In order to
optimize tracking performance across time, a quick estimate of the object's
global motion properties needs to be fed to the oculomotor system and
dynamically updated. Concurrently, performance can be greatly improved in terms
of latency and accuracy by taking into account predictive cues, especially
under variable conditions of visibility and in presence of ambiguous retinal
information. Here, we review several recent studies focusing on the integration
of retinal and extra-retinal information for the control of human smooth
pursuit.By dynamically probing the tracking performance with well established
paradigms in the visual perception and oculomotor literature we provide the
basis to test theoretical hypotheses within the framework of dynamic
probabilistic inference. We will in particular present the applications of
these results in light of state-of-the-art computer vision algorithms
Learning Online Smooth Predictors for Realtime Camera Planning using Recurrent Decision Trees
We study the problem of online prediction for realtime camera planning, where the goal is to predict smooth trajectories that correctly track and frame objects of interest (e.g., players in a basketball game). The conventional approach for training predictors does not directly consider temporal consistency, and often produces undesirable jitter. Although post-hoc smoothing (e.g., via a Kalman filter) can mitigate this issue to some degree, it is not ideal due to overly stringent modeling assumptions (e.g., Gaussian noise). We propose a recurrent decision tree framework that can directly incorporate temporal consistency into a data-driven predictor, as well as a learning algorithm that can efficiently learn such temporally smooth models. Our approach does not require any post-processing, making online smooth predictions much easier to generate when the noise model is unknown. We apply our approach to sports broadcasting: given noisy player detections, we learn where the camera should look based on human demonstrations. Our experiments exhibit significant improvements over conventional baselines and showcase the practicality of our approach
Performance of the LHCb muon system
The performance of the LHCb Muon system and its stability across the full
2010 data taking with LHC running at ps = 7 TeV energy is studied. The
optimization of the detector setting and the time calibration performed with
the first collisions delivered by LHC is described. Particle rates, measured
for the wide range of luminosities and beam operation conditions experienced
during the run, are compared with the values expected from simulation. The
space and time alignment of the detectors, chamber efficiency, time resolution
and cluster size are evaluated. The detector performance is found to be as
expected from specifications or better. Notably the overall efficiency is well
above the design requirementsComment: JINST_015P_1112 201
A SARIMAX coupled modelling applied to individual load curves intraday forecasting
A dynamic coupled modelling is investigated to take temperature into account
in the individual energy consumption forecasting. The objective is both to
avoid the inherent complexity of exhaustive SARIMAX models and to take
advantage of the usual linear relation between energy consumption and
temperature for thermosensitive customers. We first recall some issues related
to individual load curves forecasting. Then, we propose and study the
properties of a dynamic coupled modelling taking temperature into account as an
exogenous contribution and its application to the intraday prediction of energy
consumption. Finally, these theoretical results are illustrated on a real
individual load curve. The authors discuss the relevance of such an approach
and anticipate that it could form a substantial alternative to the commonly
used methods for energy consumption forecasting of individual customers.Comment: 17 pages, 18 figures, 2 table
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