44 research outputs found
Efficient Autonomous Navigation for Planetary Rovers with Limited Resources
Rovers operating on Mars are in need of more and more autonomous features to ful ll their
challenging mission requirements. However, the inherent constraints of space systems make
the implementation of complex algorithms an expensive and difficult task. In this paper
we propose a control architecture for autonomous navigation. Efficient implementations of
autonomous features are built on top of the current ExoMars navigation method, enhancing
the safety and traversing capabilities of the rover. These features allow the rover to detect
and avoid hazards and perform long traverses by following a roughly safe path planned by
operators on ground. The control architecture implementing the proposed navigation mode
has been tested during a field test campaign on a planetary analogue terrain. The experiments
evaluated the proposed approach, autonomously completing two long traverses while
avoiding hazards. The approach only relies on the optical Localization Cameras stereobench,
a sensor that is found in all rovers launched so far, and potentially allows for computationally
inexpensive long-range autonomous navigation in terrains of medium difficulty
Coupled path and motion planning for a rover-manipulator system
This paper introduces a motion planning strategy aimed
at the coordination of a rover and manipulator. The main
purpose is to fetch samples of scientific interest that could
be placed on difficult locations, requiring to maximize
the workspace of the combined system. In order to validate
this strategy, a simulation environment has been built, based on the VORTEX Studio platform. A virtual model of the ExoTer rover prototype, owned by the European Space Agency, has been used together with the same robot control software. Finally, we show in this paper the benefits of validating the proposed strategy on simulation, prior to its future use on the real experimental rover.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec
Dynamic path planning for reconfigurable rovers using a multi-layered grid
Autonomy on rovers is desirable in order to extend the traversed distance, and therefore, maximize the number
of places visited during the mission. It depends heavily on the information that is available for the traversed
surface on other planet. This information may come from the vehicle’s sensors as well as from orbital images.
Besides, future exploration missions may consider the use of reconfigurable rovers, which are able to execute
multiple locomotion modes to better adapt to different terrains. With these considerations, a path planning
algorithm based on the Fast Marching Method is proposed. Environment information coming from different
sources is used on a grid formed by two layers. First, the Global Layer with a low resolution, but high extension
is used to compute the overall path connecting the rover and the desired goal, using a cost function that takes
advantage of the rover locomotion modes. Second, the Local Layer with higher resolution but limited distance
is used where the path is dynamically repaired because of obstacle presence. Finally, we show simulation and
field test results based on several reconfigurable and non-reconfigurable rover prototypes and a experimental
terrain
Optimal path planning using a continuous anisotropicmodel for navigation on irregular terrains.
Mobile robots usually need to minimize energy when they are traversing uneven terrains. To reach a location of interest, one strategy consists of making the robot follow the path that demands the least possible amount of energy. Yet, its calculation is not trivial with irregular surfaces. Gravity makes the energy consumption of a robot change according to its heading. Such a variation is subject to the terramechanic characteristics of the surface. This paper introduces a cost function that addresses this variation when traversing slopes. This function presents direction-dependency (anisotropic) and returns the cost for all directions (continuous).. Moreover, it is compatible with the Ordered Upwind Method, which allows finding globally optimal paths in a deterministic way. Besides, the segments of these paths are not restricted to the shape of a grid. Finally, this paper also introduces the description and discussion of a simulation experiment. It served to analyse what kinds of terrain motivate the use of anisotropy. The Ordered Upwind Method was executed on a virtual crater with different terrain parameter configurations, using both isotropic (direction-non-dependent) and anisotropic cost functions. The results evince how in certain situations the use of an anisotropic cost function instead of an isotropic one produces a path that reduces the accumulated cost by up to 20%.Funding for open access publishing: Universidad de Málaga/CBUA
The development of the skill in basketball: keys for the formation process of the high performance player
Recientes investigaciones han puesto de manifiesto la dificultad de predecir resultados futuros a partir de los mecanismos tradicionales
en la detección de talentos. Como consecuencia de esta problemática se vienen realizando estudios que se centran en el
desarrollo de la pericia. La intención es conocer con detalle el itinerario deportivo de aquellos que han alcanzado grandes éxitos
(expertos) para intentar adaptarlo a las futuras promesas. Con este planteamiento se pone más énfasis en el cuidado del talento que
en la detección. En esta investigación se ha comparado el itinerario deportivo de 7 jugadores internacionales de baloncesto en activo
con el objetivo de aportar más conocimiento sobre el proceso de formación del jugador de alto rendimiento. A través del análisis
cualitativo de las entrevistas se ha conformado un modelo de desarrollo de la pericia en donde se observa la compleja interacción del
contexto, la práctica y las motivaciones en el proceso de formación del jugador de alto rendimiento.Recent research studies have shown the difficulty of predicting future results based on traditional mechanisms in talent detection.
As a consequence, studies focused on expertise development have been conducted. The aim is to know in detail the sports path of
those who have achieved great success (experts) in order to try to adapt it to the new promising sportspeople. This approach focuses
more on talent care than on talent detection. In the present research we have compared the sports paths of 7 international active
basketball players with the aim of providing more knowledge on the high performance player formation process. Through the qualitative
analysis of the interviews, a model of expertise development has been created, where the complex interaction of the context,
the practice and motivations in the formation process of the high performance player are observed
Detección de ca liberibacter solanacearum y fitoplasmas en cultivo de papa (solanum tuberosum l.) en el valle de toluca
Título en ingles: Detection of Ca Liberibacter solanacearum and phytoplasma in potato crop (Solanum tuberosum L.) in Toluca Valley Título corto: Detección de Ca Liberibacter solanacearum y fitoplasmas Resumen En México y Centro América se han detectado tubérculos de papa con manchado interno. Recientemente en Texas EUA a esta enfermedad se le ha denominado “Zebra Chip” (ZC) o rayado de la papa, los síntomas foliares se asemejan al síndrome denominado “Punta Morada de la Papa” (PMP) o enfermedad del “amarillamiento por psilidos” la cual es asociada con la presencia de “Candidatus Liberibacter solanacearum”. El objetivo de esta investigación fue detectar la presencia de esta bacteria y de fitoplasmas en plantas de papa que presentaban la coloración purpura de los foliolos. Durante el ciclo primavera – verano 2011 y 2012 se hizo un muestreo en los municipios de Tenango del Valle, Zinacantepec, Villa de Allende y San José del Rincón, del Estado de México. La detección de ambos patógenos se realizó mediante la reacción en cadena de la polimerasa (PCR) con los iniciadores específicos para fitoplasmas: P1/P7, R16mF2/R16mR1 y para Ca Liberibacter solanacearum: OA2/Oi2c, resultando el 35,8% de las plantas positivas para fitoplasmas y el 11,6% para la bacteria. Los resultados indican que en algunas regiones productoras de papa del Estado de México, los dos presuntos agentes causales del síndrome de PMP, fitoplasmas y Ca. Liberibacter solanacearum, pueden estar asociados. Palabras clave: Candidatus Liberibacter solanacearum; Fitoplasma; punta morada. Abstract In Mexico and Central America have been detected stained potato tubers with internal browning; recently in Texas, USA, this disease has been called "Zebra Chip" (ZC) or striped potato, foliar symptoms resemble the syndrome called "Potato Purple Top" (PPT) or "psyllid yellows" disease which is associated with the presence of "Candidatus liberibacter solanacearum”. The aim of the current work was to detect the presence of this bacterium and phytoplasma in potato plants with purple top symptoms. During 2011 and 2012 Spring – Summer cycle, a directed sampling was carried out in Tenango del Valle, Zinacantepec, Villa de Allende and San José del Rincón, State of México. The detection of both pathogens was performed by Polymerase Chain Reaction (PCR) with specific primers for phytoplasmas: P1/ P7, R16mF2/R16mR1 and for Ca Liberacter solanacearum: OA2/Oi2c, being 35,8 % from the positive plants for phytoplasmas and 11,6 % for this bacterium. These results indicated that in some areas these two PPT syndrome suspected causative agents, phytoplasmas and Ca. Liberibacter solanacearum, could be associated in the State of Mexico potato-producing region. Key words: Candidatus Liberibacter solanacearum; Phytoplasm; Purple Top
Hydroxychloroquine is associated with a lower risk of polyautoimmunity: data from the RELESSER Registry
Objectives. This article estimates the frequency of polyautoimmunity and associated factors in a large retrospective cohort of patients with SLE. Methods. RELESSER (Spanish Society of Rheumatology Lupus Registry) is a nationwide multicentre, hospital-based registry of SLE patients. This is a cross-sectional study. The main variable was polyautoimmunity, which was defined as the co-occurrence of SLE and another autoimmune disease, such as autoimmune thyroiditis, RA, scleroderma, inflammatory myopathy and MCTD. We also recorded the presence of multiple autoimmune syndrome, secondary SS, secondary APS and a family history of autoimmune disease. Multiple logistic regression analysis was performed to investigate possible risk factors for polyautoimmunity. Results. Of the 3679 patients who fulfilled the criteria for SLE, 502 (13.6%) had polyautoimmunity. The most frequent types were autoimmune thyroiditis (7.9%), other systemic autoimmune diseases (6.2%), secondary SS (14.1%) and secondary APS (13.7%). Multiple autoimmune syndrome accounted for 10.2% of all cases of polyautoimmunity. A family history was recorded in 11.8%. According to the multivariate analysis, the factors associated with polyautoimmunity were female sex [odds ratio (95% CI), 1.72 (1.07, 2.72)], RP [1.63 (1.29, 2.05)], interstitial lung disease [3.35 (1.84, 6.01)], Jaccoud arthropathy [1.92 (1.40, 2.63)], anti-Ro/SSA and/or anti-La/SSB autoantibodies [2.03 (1.55, 2.67)], anti-RNP antibodies [1.48 (1.16, 1.90)], MTX [1.67 (1.26, 2.18)] and antimalarial drugs [0.50 (0.38, 0.67)]. Conclusion. Patients with SLE frequently present polyautoimmunity. We observed clinical and analytical characteristics associated with polyautoimmunity. Our finding that antimalarial drugs protected against polyautoimmunity should be verified in future studies
Comprehensive description of clinical characteristics of a large systemic Lupus Erythematosus Cohort from the Spanish Rheumatology Society Lupus Registry (RELESSER) with emphasis on complete versus incomplete lupus differences
Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by multiple organ involvement and pronounced racial and ethnic heterogeneity. The aims of the present work were (1) to describe the cumulative clinical characteristics of those patients included in the Spanish Rheumatology Society SLE Registry (RELESSER), focusing on the differences between patients who fulfilled the 1997 ACR-SLE criteria versus those with less than 4 criteria (hereafter designated as incomplete SLE (iSLE)) and (2) to compare SLE patient characteristics with those documented in other multicentric SLE registries. RELESSER is a multicenter hospital-based registry, with a collection of data from a large, representative sample of adult patients with SLE (1997 ACR criteria) seen at Spanish rheumatology departments. The registry includes demographic data, comprehensive descriptions of clinical manifestations, as well as information about disease activity and severity, cumulative damage, comorbidities, treatments and mortality, using variables with highly standardized definitions. A total of 4.024 SLE patients (91% with ≥4 ACR criteria) were included. Ninety percent were women with a mean age at diagnosis of 35.4 years and a median duration of disease of 11.0 years. As expected, most SLE manifestations were more frequent in SLE patients than in iSLE ones and every one of the ACR criteria was also associated with SLE condition; this was particularly true of malar rash, oral ulcers and renal disorder. The analysis-adjusted by gender, age at diagnosis, and disease duration-revealed that higher disease activity, damage and SLE severity index are associated with SLE [OR: 1.14; 95% CI: 1.08-1.20 (P < 0.001); 1.29; 95% CI: 1.15-1.44 (P < 0.001); and 2.10; 95% CI: 1.83-2.42 (P < 0.001), respectively]. These results support the hypothesis that iSLE behaves as a relative stable and mild disease. SLE patients from the RELESSER register do not appear to differ substantially from other Caucasian populations and although activity [median SELENA-SLEDA: 2 (IQ: 0-4)], damage [median SLICC/ACR/DI: 1 (IQ: 0-2)], and severity [median KATZ index: 2 (IQ: 1-3)] scores were low, 1 of every 4 deaths was due to SLE activity. RELESSER represents the largest European SLE registry established to date, providing comprehensive, reliable and updated information on SLE in the southern European population
Marco de Fundamentación de las pruebas de la Evaluación Censal de Estudiantes. Segundo grado de primaria, cuarto grado de primaria EIB, cuarto grado de primaria (no EIB), segundo grado de secundaria
La Evaluación Censal de Estudiantes (ECE) se enmarca en las evaluaciones de sistema y es un esfuerzo del Minedu por ofrecer la oportunidad de contar con información válida, confiable y comparable, para reflexionar sobre ella y sobre los rumbos que se podrían tomar con el fin de ofrecer mayores y mejores oportunidades de aprendizaje a los estudiantes. De ese modo, la ECE es útil no solo para los gobiernos regionales y locales, y las distintas instancias del sistema educativo, sino también para las escuelas, pues les permite conocer sus resultados como institución y orientar así sus procesos pedagógicos. La construcción de una evaluación de sistema es una tarea que, por su envergadura, es de alta responsabilidad y complejidad. Es de alta responsabilidad porque sus resultados repercuten en el diseño de políticas educativas en varios niveles, lo cual implica que la evaluación estandarizada debe constituirse en un proceso legitimado socialmente. Asimismo, es una tarea compleja debido a los procesos altamente técnicos que implica y a la magnitud del operativo, todo ello con el fin de conseguir legitimidad (validez, confiabilidad, cobertura, estandarización, accesibilidad, probidad y confidencialidad) en los resultados. Así, la construcción de la ECE también es sensible a las diferencias individuales y culturales