3,397 research outputs found
Measuring the Muon Content of Air Showers with IceTop
IceTop, the surface component of the IceCube detector, has been used to
measure the energy spectrum of cosmic ray primaries in the range between 1.58
PeV and 1.26 EeV. It can also be used to study the low energy muons in air
showers by looking at large distances (> 300m) from the shower axis. We will
show the muon lateral distribution function at large lateral distances as
measured with IceTop and discuss the implications of this measurement. We also
discuss the prospects for low energy muon studies with IceTop.Comment: 5 pages, 9 figures, presented at the 18th meeting of the
International Symposium on Very High Energy Cosmic Ray Interactions (ISVHECRI
2014
Real-Time odor classification through sequential bayesian filtering
The classification of volatiles substances with an e-nose is still a challenging problem, particularly when working under real-time, out-of-the-lab environmental conditions where the
chaotic and highly dynamic characteristics of the gas
transportation induce an almost permanent transient state in the e-nose readings. In this work, a sequential Bayesian filtering approach is proposed to efficiently integrate information from previous e-nose observations while updating the belief about the gas class on a real-time basis. We validate our proposal with two
real olfaction datasets composed of dynamic time-series experiments (gas transitions are Considered, but no mixture of gases), showing an improvement in the classification rate when compared to a stand-alone probabilistic classifier.Universidad de Málaga. Campus de Excelencia Internacional AndalucĂa Tech
Planar Odometry from a Radial Laser Scanner. A Range Flow-based Approach
In this paper we present a fast and precise method to estimate the planar motion of a lidar from consecutive range scans. For every scanned point we formulate the range flow constraint equation in terms of the sensor velocity, and
minimize a robust function of the resulting geometric constraints to obtain the motion estimate. Conversely to traditional
approaches, this method does not search for correspondences but performs dense scan alignment based on the scan gradients,
in the fashion of dense 3D visual odometry. The minimization problem is solved in a coarse-to-fine scheme to cope with large displacements, and a smooth filter based on the covariance of the estimate is employed to handle uncertainty in unconstraint scenarios (e.g. corridors). Simulated and real experiments have
been performed to compare our approach with two prominent scan matchers and with wheel odometry. Quantitative and qualitative results demonstrate the superior performance of our approach which, along with its very low computational cost (0.9 milliseconds on a single CPU core), makes it suitable for those robotic applications that require planar odometry. For this purpose, we also provide the code so that the robotics community can benefit from it.Universidad de Málaga. Campus de Excelencia Internacional AndalucĂa Tech. Spanish Government under project DPI2014-55826-R and the grant program FPI-MICINN 2012
Online Estimation of 2D Wind Maps for Olfactory Robots
This work introduces a novel solution to approximate in real time the 2D wind flow present in a geometrically known environment. It is grounded on the probabilistic
framework provided by a Markov random field and enables the
estimation of the most probable wind field from a set of noisy observations, for the case of incompressible and steady wind flow. Our method delivers reasonably precise results without falling into common unrealistic assumptions like homogeneous wind
flow, absence of obstacles, etc., and performs very efficiently (less
than 0.5 seconds for an environment represented with a 100x100
cell grid). This approach is then quite suitable for applications
that require real-time estimation of the wind flow, as for example, the localization of gas sources, prediction of the gas dispersion, or the mapping of the gas distribution of different chemicals released in a given scenario.Universidad de Málaga. Campus de Excelencia Internacional AndalucĂa Tech
A Robotic Experiment Toward Understanding Human Gas-Source Localization Strategies
This paper describes an experiment for gas-source localization with a human-teleoperated mobile robot devised to gather data on how humans search for odor-sources. To that end,
more than 150 repetitions of the search process are recorded for 69 test subjects, under 4 sensor configurations (including electronic nose, anemometer and video camera) and 4 scenarios (i.e. with different wind-flow conditions and gas-source position). The experiment has been carried out with a ROS-based simulator that allows driving the robot while recording data of interest (e.g. driving
commands, robot localization, sensor measurements, groundtruth,
etc.) for further analyzing the human process of gas-source searching, and computational fluid dynamics (CFD) to generate realistic and repeatable test conditions. The manuscript describes the different environmental parameters and sensor combinations of the experiment, and explains the methodology under which it was executed. The obtained dataset is publicly available at
http://mapir.isa.uma.es/mapirwebsite/index.php/253-gsl-dataset.Universidad de Málaga. Campus de Excelencia Internacional AndalucĂa Tech
Gluino Air Showers as a Signal of Split Supersymmetry
It has been proposed recently that, within the framework of split
Supersymmetry, long lived gluinos generated in astrophysical sources could be
detected using the signatures of the air showers they produce, thus providing a
lower bound for their lifetime and for the scale of SUSY breaking. We present
the longitudinal profile and lateral spread of -hadron induced extensive air
showers and consider the possibility of measuring them with a detector with the
characteristics of the Pierre Auger Observatory.Comment: 4 pages, 3 eps figure
A Configurable Smart E-Nose for Spatio-Temporal Olfactory Analysis
This paper describes a novel electronic nose (enose) aimed at applications that require knowing not only the gas composition and concentration, but also its temporal and spatial evolution. This is done by capturing additional
information related to the chemical substance such as the timestamp and geo-location of the measurements, as well as other physical magnitudes of the environment like temperature and humidity for correcting and interpreting the data. The device has been conceived following a modular architecture as a set of independent smart modules, which are interconnected and
controlled through an I2C interface by a central processing unit. Each smart module can identify itself, store settings for autoconfiguration
and perform signal pre-processing of the measured
variables. Smart module types include: chemical sensors, communication interfaces, batteries, data storage, GPS, temperature and humidity.Universidad de Málaga. Campus de Excelencia Internacional AndalucĂa Tech
Creating maps of VOC odors in urban areas by cycling with a portable e-nose
This work describes an application for monitoring volatile organic compounds (VOCs) in urban areas, likely coming from residential waste or the public sewage system. The objective is to obtain a spatial and temporal representation of such odors by means of a gas distribution map, from which valuable information such as the location, or the time-intervals of maximum strength of the nuisance odors can be inferred. The necessary data: chemical, temporal and spatial; is provided by a GPS and a specific e-nose accommodating eight metal oxide (MOX) gas sensors, both mounted on a bicycle.
The results of a monitoring campaign carried out in a town in southern Spain are presented. The campaign comprises nine measurement runs distributed along three consecutive days, with a total path of more than 90Km. Fig.1 shows an illustrative example of the data collected during this process, and the generated geo-referenced gas distribution maps. As can be appreciated, the chemical, temporal and spatial data are successfully merged to obtain representative information about the presence of VOCs in the urban area. A deeper analysis comprising the study of the areas showing the higher VOCs concentration, as well as the temporal variability among the different days and hours within the day are also provided.Universidad de Málaga. Campus de Excelencia Internacional AndalucĂa Tech.Proyectos de Excelencia de la Junta de AndalucĂa: TEP08-4016 y TEP2012-53
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