4,939 research outputs found
A Ground Control Station for Collaborative Unmanned Surface Vehicles
[ES] El Centro de Control de Tierra (CCT) es uno de los elementos imprescindibles para la supervisión y control de vehículos autónomos que realizan misiones complejas. En la actualidad cada vez hay más aplicaciones donde se utilizan múltiples vehículos autónomos y el tradicional Centro de Control está evolucionando para ser capaz de gestionar diversos vehículos y operadores. Este artículo presenta las características más relevantes de un CCT adaptable y versátil, especialmente diseñado para que un equipo heterogéneo de operadores puedan monitorizar y supervisar el funcionamiento colaborativo de un conjunto heterogéneo de vehículos autónomos. Entre estas características destacan la posibilidad de, según las necesidades de los operadores y de la misión, 1) reconfigurar cuál (y cómo) es la información que se muestra de cada vehículo a cada operador, 2) definir alarmas que atraigan la atención de los operadores ante determinados eventos (y liberen su carga de trabajo mientras estos no se den) y 3) re-asignar en tiempo real la gestión de los vehículos a los diferentes operadores. Para alcanzarlas, se ha realizado un cuidadoso diseño de la arquitectura software del CCT, que se detalla en el artículo y que se encuentra formada por: un módulo de comunicaciones; un módulo planificador de alto nivel; un módulo (replicable en tantos equipos como se desee) de monitorización y supervisión de vehículos; y tantos módulos comandadores como vehículos diferentes existan en la misión. Este CCT ha sido desarrollado dentro del proyecto de investigación SALACOM (Sistema Autónomo de Localización y Actuación ante Contaminantes en el Mar), en el que dos barcos autónomos maniobran de forma colaborativa para desplegar una barrera para la contención de un vertido contaminante en el mar ydonde la incorporación del operador en la supervisión y control de las maniobras de los vehículos es un requisito imprescindible para dar seguridad y confianza a la operación realizada. Finalmente, se presenta un caso de uso del Centro de Control de Tierra donde se realiza una maniobra de seguimiento entre dos vehículos autónomos de superficie.[EN] The Ground Control Station (GCS) is one of the essential elements to supervise and control autonomous vehicles performing complex missions. The increasing number of systems that involve multiple autonomous vehicles is making traditional GCSs evolve to let them handle dierent vehicles and operators. In this article, we present the more relevant properties of a versatile adaptable GCS that has been especially designed to let multiple operators, each using a dierent computer equipment, be in charge of controlling a heterogeneous team of autonomous vehicles. Its main properties are the possibility of 1) reconfiguring which information is displayed to each operator, 2) defining alarms to draw the operators attention when required, and 3) re-assigning, in real-time, the vehicles to dierent operators. These properties are supported by a distributed design of the GCS software architecture, presented in the paper and consistent of: a communication module, a high level planner, replicable monitoring and supervising units, and as many commanders as vehicles within each mission. This GCS has been developed within SALACOM (an autonomous system for locating and acting against sea spills), where two Unmanned Surface Vehicles (USVs) cooperate to collect a sea spill under the supervision of several operators that are responsible of the security of the mission. Finally, this paper also presents a case of use of the GCS within a real-world experiment involving two USVs performing leader-follower formation maneouvres.Los autores del art´ıculo quieren agradecer al Ministerio de Econom´ıa y Competitividad español su apoyo a través del proyecto SALACOM (DPI2013-46665-C2-1-R).Bonache Seco, J.; Dormido Canto, J.; Montalvo Martinez, M.; López-Orozco, J.; Besada Portas, E.; De La Cruz Garcia, J. (2017). Centro de Control de Tierra para Colaboración de Vehículos Autónomos Marinos. Revista Iberoamericana de Automática e Informática industrial. 15(1):1-11. https://doi.org/10.4995/riai.2017.8737OJS111151ASTM, 2017. Committee F41 on unmanned maritime vehicle systems (umvs). 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A., Besada-Portas, E., Aranda-Almansa, J., 2015. A streamlined nonlinear path following kinematic controller. In: 2015 IEEE International Conference on Robotics and Automation (ICRA). IEEE, pp. 6394-6401. https://doi.org/10.1109/ICRA.2015.7140097Heo, J., Kim, S., Kwon, Y., 2016. Design of ground control station for operation of multiple combat entities. Journal of Computer and Communications 4, 66-71. https://doi.org/10.4236/jcc.2016.45010Lalish, E., Morgansen, K. A., 2008. Decentralized reactive collision avoidance for multivehicle systems. In: Proceedings of the 47th IEEE Conference on Decision and Control. IEEE, pp. 1218-1224. https://doi.org/10.1109/CDC.2008.4738894Lapierre, L., Soetanto, D., 2007. Nonlinear path-following control of an auv. Ocean engineering 34 (11), 1734-1744. https://doi.org/10.1016/j.oceaneng.2006.10.019LibrePilot, 2015. Software suite to control multicopter and other rc-models. 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R., Steimle, E., Griffin, C., Cullins, C., Hall, M., Pratt, K., 2008. Cooperative use of unmanned sea surface and micro aerial vehicles at hurricane wilma. Journal of Field Robotics 25 (3), 164-180. https://doi.org/10.1002/rob.20235Park, S., Deyst, J., How, J. P., 2007. Performance and lyapunov stability of a nonlinear path following guidance method. Journal of Guidance, Control, and Dynamics 30 (6), 1718-1728. https://doi.org/10.2514/1.28957Patterson, M. C., Mulligan, A., Boiteux, F., 2013. Safety and security applications for micro-unmanned surface vessels. In: 2013 OCEANS-San Diego. IEEE, pp. 1-6.QGroundControl, 2017. A uav control station. [Online] http://qgroundcontrol.com/, accedido en Marzo de 2017.Ribas, D., Palomeras, N., Ridao, P., Carreras, M., Mallios, A., 2012. Girona 500 auv: From survey to intervention. IEEE ASME Transactions on Mechatronics 17 (1), 46-53. https://doi.org/10.1109/TMECH.2011.2174065STANAG4586, 2012. Standard interfaces of uav control system (ucs) for nato uav interoperability, ed. 3. NATO standardization agency (nsa). [Online] http://nso.nato.int/nso/nsdd/listpromulg.html.Sutton, R., Sharma, S., Xao, T., 2011. Adaptive navigation systems for an unmanned surface vehicle. Journal of Marine Engineering & Technology 10 (3), 3-20.Walter, B. E., Knutzon, J. S., Sannier, A. V., Oliver, J. H., 2004. Virtual uav ground control station. In: AIAA 3rd Unmanned Unlimited Technical Conference, Workshop and Exhibit. https://doi.org/10.2514/6.2004-6320WGSM, 2017. Wave glider management system. [Online] https://www.liquidrobotics.com/platform/software/
The reproductive capacity of Monk Parakeets Myiopsitta monachus is higher in their invasive range
Breeding parameters for Monk Parakeets Myiopsitta monachus nesting in Barcelona, Spain, were collected for 651 nests over five breeding seasons. This invasive population has a high reproductive capacity compared with the species in the native range: fledging success was double, the percentage of pairs attempting second broods three times higher and 55% of first-year birds bred compared with almost zero in South America
Overexpression of CYB5R3 and NQO1, Two NAD\u3csup\u3e+\u3c/sup\u3e-Producing Enzymes, Mimics Aspects of Caloric Restriction
Calorie restriction (CR) is one of the most robust means to improve health and survival in model organisms. CR imposes a metabolic program that leads to increased stress resistance and delayed onset of chronic diseases, including cancer. In rodents, CR induces the upregulation of two NADH‐dehydrogenases, namely NAD(P)H:quinone oxidoreductase 1 (Nqo1) and cytochrome b5 reductase 3 (Cyb5r3), which provide electrons for energy metabolism. It has been proposed that this upregulation may be responsible for some of the beneficial effects of CR, and defects in their activity are linked to aging and several age‐associated diseases. However, it is unclear whether changes in metabolic homeostasis solely through upregulation of these NADH‐dehydrogenases have a positive impact on health and survival. We generated a mouse that overexpresses both metabolic enzymes leading to phenotypes that resemble aspects of CR including a modest increase in lifespan, greater physical performance, a decrease in chronic inflammation, and, importantly, protection against carcinogenesis, one of the main hallmarks of CR. Furthermore, these animals showed an enhancement of metabolic flexibility and a significant upregulation of the NAD+/sirtuin pathway. The results highlight the importance of these NAD+ producers for the promotion of health and extended lifespan
Gauge and Scheme Dependence of Mixing Matrix Renormalization
We revisit the issue of mixing matrix renormalization in theories that
include Dirac or Majorana fermions. We show how a gauge-variant on-shell
renormalized mixing matrix can be related to a manifestly gauge-independent one
within a generalized scheme of renormalization. This
scheme-dependent relation is a consequence of the fact that in any scheme of
renormalization, the gauge-dependent part of the mixing-matrix counterterm is
ultra-violet safe and has a pure dispersive form. Employing the unitarity
properties of the theory, we can successfully utilize the afore-mentioned
scheme-dependent relation to preserve basic global or local symmetries of the
bare Lagrangian through the entire process of renormalization. As an immediate
application of our study, we derive the gauge-independent renormalization-group
equations of mixing matrices in a minimal extension of the Standard Model with
isosinglet neutrinos.Comment: 31 pages, LaTeX, uses axodraw.st
Recommended from our members
A Search for Dark Higgs Bosons
Recent astrophysical and terrestrial experiments have motivated the proposal
of a dark sector with GeV-scale gauge boson force carriers and new Higgs
bosons. We present a search for a dark Higgs boson using 516 fb-1 of data
collected with the BABAR detector. We do not observe a significant signal and
we set 90% confidence level upper limits on the product of the Standard
Model-dark sector mixing angle and the dark sector coupling constant.Comment: 7 pages, 5 postscript figures, published version with improved plots
for b/w printin
Search for the standard model Higgs boson in the H to ZZ to 2l 2nu channel in pp collisions at sqrt(s) = 7 TeV
A search for the standard model Higgs boson in the H to ZZ to 2l 2nu decay
channel, where l = e or mu, in pp collisions at a center-of-mass energy of 7
TeV is presented. The data were collected at the LHC, with the CMS detector,
and correspond to an integrated luminosity of 4.6 inverse femtobarns. No
significant excess is observed above the background expectation, and upper
limits are set on the Higgs boson production cross section. The presence of the
standard model Higgs boson with a mass in the 270-440 GeV range is excluded at
95% confidence level.Comment: Submitted to JHE
Search for anomalous t t-bar production in the highly-boosted all-hadronic final state
A search is presented for a massive particle, generically referred to as a
Z', decaying into a t t-bar pair. The search focuses on Z' resonances that are
sufficiently massive to produce highly Lorentz-boosted top quarks, which yield
collimated decay products that are partially or fully merged into single jets.
The analysis uses new methods to analyze jet substructure, providing
suppression of the non-top multijet backgrounds. The analysis is based on a
data sample of proton-proton collisions at a center-of-mass energy of 7 TeV,
corresponding to an integrated luminosity of 5 inverse femtobarns. Upper limits
in the range of 1 pb are set on the product of the production cross section and
branching fraction for a topcolor Z' modeled for several widths, as well as for
a Randall--Sundrum Kaluza--Klein gluon. In addition, the results constrain any
enhancement in t t-bar production beyond expectations of the standard model for
t t-bar invariant masses larger than 1 TeV.Comment: Submitted to the Journal of High Energy Physics; this version
includes a minor typo correction that will be submitted as an erratu
Search for New Physics with Jets and Missing Transverse Momentum in pp collisions at sqrt(s) = 7 TeV
A search for new physics is presented based on an event signature of at least
three jets accompanied by large missing transverse momentum, using a data
sample corresponding to an integrated luminosity of 36 inverse picobarns
collected in proton--proton collisions at sqrt(s)=7 TeV with the CMS detector
at the LHC. No excess of events is observed above the expected standard model
backgrounds, which are all estimated from the data. Exclusion limits are
presented for the constrained minimal supersymmetric extension of the standard
model. Cross section limits are also presented using simplified models with new
particles decaying to an undetected particle and one or two jets
Combined search for the quarks of a sequential fourth generation
Results are presented from a search for a fourth generation of quarks
produced singly or in pairs in a data set corresponding to an integrated
luminosity of 5 inverse femtobarns recorded by the CMS experiment at the LHC in
2011. A novel strategy has been developed for a combined search for quarks of
the up and down type in decay channels with at least one isolated muon or
electron. Limits on the mass of the fourth-generation quarks and the relevant
Cabibbo-Kobayashi-Maskawa matrix elements are derived in the context of a
simple extension of the standard model with a sequential fourth generation of
fermions. The existence of mass-degenerate fourth-generation quarks with masses
below 685 GeV is excluded at 95% confidence level for minimal off-diagonal
mixing between the third- and the fourth-generation quarks. With a mass
difference of 25 GeV between the quark masses, the obtained limit on the masses
of the fourth-generation quarks shifts by about +/- 20 GeV. These results
significantly reduce the allowed parameter space for a fourth generation of
fermions.Comment: Replaced with published version. Added journal reference and DO
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