3,269 research outputs found

    LEGO© Mindstorms NXT and Q-Learning: a teaching approach for robotics in engineering

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    Robotics has become a common subject in many engineering degrees and postgraduate programs. Although at undergraduate levels the students are introduced to basic theoretical concepts and tools, at postgraduate courses more complex topics have to be covered. One of those advanced subjects is Cognitive Robotics, which covers aspects like automatic symbolic reasoning, decision-making, task planning or machine learning. In particular, Reinforcement Learning (RL) is a machine learning and decision-making methodology that does not require a model of the environment where the robot operates, overcoming this limitation by making observations. In order to get the greatest educational benefit, RL theory should be complemented with some hands-on RL task that uses a real robot, so students get a complete vision of the learning problem, as well as of the issues that arise when dealing with a physical robotic platform. There are several RL techniques that can be studied in such a subject; we have chosen Q-learning, since is a simple, effective and well-known RL algorithm. In this paper we present a minimalist implementation of the Q-learning method for a Lego Mindstorms NXT mobile robot, focused on simplicity and applicability, and flexible enough to be adapted to several tasks. Starting from a simple wandering problem, we first design an off-line model of the learning process in which the Q-learning parameters are studied. After that, we implement the algorithm on the robot, gradually enlarging the number of states-actions of the problem. The final result of this work is a teaching framework for developing practical activities regarding Q-learning in our Robotics subjects, which will improve our teaching.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    On the parallelization of a three-parametric log-logistic estimation algorithm

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    Networked telerobots transmit data from its sensors to the remote controller. To provide guarantees on the time requirements of these systems it is mandatory to keep the transmission time delays below a given threshold, and to that end we should predict them. In this paper we tackle the parallelization of a procedure that models these stochastic time delays. More precisely, we focus on fitting the time delay signal using a three-parametrical log-logistic distribution. Since, the robot and the controller are powered by multicore processors and, mainly on the robot, the energy consumption is a relevant issue, we study different alternatives to optimize both performance and energy usage of the aforesaid algorithm. Two quad-core processors are considered: a low power Intel Core i7 (45W TDP) and a ultra low power Samsung Exynos 5 (6W TDP). Results show that parallelism is beneficial, but that not all the cores should be exploited if the system is targeted at optimizing a performance-energy tradeoff.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Hierarchical regulation of sensor data transmission for networked telerobots

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    Networked telerobots carry sensors that send data, with stochastic transmission times, to a remote human operator, who must execute some real-time control task (e.g., navigation). In this paper we propose to regulate the sensory information being transmitted in order to guarantee soft real-time requirements and also optimize the quality of control, through a novel two-level hierarchical controller that both varies the amount of transmitted sensor data and dynamically reconfigures active sensors. Our controller has been implemented in a web-based teleoperator interface that is highly portable (it runs on desktop PCs, tablets, smartphones, etc.) and non-invasive, i.e., requires minimal modifications in the existing components of the system, thus being suitable for many applications. Here we present our regulation methods and the results of some experiments. They demonstrate the maximization of the transmitted data while guaranteeing the real-time requirements.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    CuMV VLPs Containing the RBM from SARS-CoV-2 Spike Protein Drive Dendritic Cell Activation and Th1 Polarization.

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    Dendritic cells (DCs) are the most specialized and proficient antigen-presenting cells. They bridge innate and adaptive immunity and display a powerful capacity to prime antigen-specific T cells. The interaction of DCs with the receptor-binding domain of the spike (S) protein from the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a pivotal step to induce effective immunity against the S protein-based vaccination protocols, as well as the SARS-CoV-2 virus. Herein, we describe the cellular and molecular events triggered by virus-like particles (VLPs) containing the receptor-binding motif from the SARS-CoV-2 spike protein in human monocyte-derived dendritic cells, or, as controls, in the presence of the Toll-like receptors (TLR)3 and TLR7/8 agonists, comprehending the events of dendritic cell maturation and their crosstalk with T cells. The results demonstrated that VLPs boosted the expression of major histocompatibility complex molecules and co-stimulatory receptors of DCs, indicating their maturation. Furthermore, DCs' interaction with VLPs promoted the activation of the NF-kB pathway, a very important intracellular signalling pathway responsible for triggering the expression and secretion of proinflammatory cytokines. Additionally, co-culture of DCs with T cells triggered CD4+ (mainly CD4+Tbet+) and CD8+ T cell proliferation. Our results suggested that VLPs increase cellular immunity, involving DC maturation and T cell polarization towards a type 1 T cells profile. By providing deeper insight into the mechanisms of activation and regulation of the immune system by DCs, these findings will enable the design of effective vaccines against SARS-CoV-2

    Optimizing subject design, timing, and focus in a diversity of engineering courses through the use of a low-cost Arduino shield

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    This paper describes the design, implementation and evaluation of a novel circuitry that extends the popular Arduino UNO microcontroller board to facilitate multiple educational activities in engineering courses. In particular, the aim of this board, the UMA-AEB, is to minimize the overhead that is usually imposed on the students before they can conduct the actual exercises, yet retain the valuable experiences that could otherwise not be acquired with simulated experiments or inflexible electronic training-benches.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. This work has been supported by the University of Málaga (Spain) through the educational innovation project PIE-15-093 “Innovación en el trabajo en laboratorio de una diversidad de asignaturas de ingeniería mediante el diseño y aplicación de una extensión de la plataforma de hardware abierto Arduino”

    High proportion of smaller ranged hummingbird species coincides with ecological specialization across the Americas.

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    Ecological communities that experience stable climate conditions have been speculated to preserve more specialized interspecific associations and have higher proportions of smaller ranged species (SRS). Thus, areas with disproportionally large numbers of SRS are expected to coincide geographically with a high degree of community-level ecological specialization, but this suggestion remains poorly supported with empirical evidence. Here, we analysed data for hummingbird resource specialization, range size, contemporary climate, and Late Quaternary climate stability for 46 hummingbird-plant mutualistic networks distributed across the Americas, representing 130 hummingbird species (ca 40% of all hummingbird species). We demonstrate a positive relationship between the proportion of SRS of hummingbirds and community-level specialization, i.e. the division of the floral niche among coexisting hummingbird species. This relationship remained strong even when accounting for climate, furthermore, the effect of SRS on specialization was far stronger than the effect of specialization on SRS, suggesting that climate largely influences specialization through species' range-size dynamics. Irrespective of the exact mechanism involved, our results indicate that communities consisting of higher proportions of SRS may be vulnerable to disturbance not only because of their small geographical ranges, but also because of their high degree of specialization

    Knowledge, attitudes and preventive practices of primary health care professionals towards alcohol use: A national, cross-sectional study.

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    Introduction Primary care (PC) professionals' knowledge about alcohol use has been identified as one of the barriers PC providers face in their clinic. Both PC professionals’ level of training and attitude are crucial in the clinical practice regarding alcohol use. Objective To evaluate the knowledge, attitude, and preventive practices of Spanish PC physicians and nurses towards alcohol use. Design An observational, descriptive, cross-sectional, multi-center study. Methodology Location: PC centers of the Spanish National Health System (NHS). Participants: PC physicians and nurses selected randomly from health care centers, and by sending an e-mail to semFYC and SEMERGEN members. Healthcare providers completed an online survey on knowledge, attitude, and follow-up recommendations for reducing alcohol intake. A descriptive, bivariate, and multivariate statistical analysis was conducted (p<0.05). Results Participants: 1,760 healthcare providers completed the survey (75.6% [95% CI 73.5–77.6] family physicians; 11.4% [95% CI 9.9–12.9] medical residents; and 12.5% [95% CI 10.9–14.1] nurses), with a mean age of 44.7 (SD 11.24, range: 26–64, 95% CI: 47.2–48.2). Knowledge was higher in family physicians (p<0.001), older professionals (Spearman's r = 0.11, p<0.001), and resident trainers (p<0.001). The PC professional most likely to provide advice for reducing alcohol use was: a nurse (p <0.001), female (p = 0.010), between 46 and 55 years old (p <0.001). Conclusions PC providers’ knowledge and preventive practices regarding alcohol use are scarce, hence specific training strategies to increase their knowledge and improve their attitude and skills with regard to this health problem should be considered a healthcare policy priority.post-print507 K

    TLR2 deficiency by compromising p19 (IL-23) expression limits T helper 17 cell responses to Mycobacterium tuberculosis

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    The authors are grateful to Drs. Manuel Teixeira da Silva, Fernando Rodrigues, Margarida Correia-Neves and Paul S. Redford for critically reading this manuscript and thank the personnel at the ICVS animal house facility for excellent animal husbandry.CD4+ Th1 cells producing IFN-γ are of extreme importance in controlling infections by Mycobacterium tuberculosis both in mice and in men. In addition to IFN-γ-producing T cells, IL-17-producing T cells (Th17) have been observed during mycobacterial infections. Nevertheless, their contribution for the host immune response to mycobacteria as well as the signals triggering M. tuberculosis -specific Th17 cell differentiation and maintenance are not fully understood. We show that signaling via Toll-like receptor (TLR) 2 has a major impact on the regulation of p19 (IL-23) expression in response to M. tuberculosis and therefore on the establishment of Th17 cell responses to M. tuberculosis infection. Diminished Th17 responses in the lung of M. tuberculosis -infected TLR2-deficient animals were not caused by defective cell differentiation in the draining lymph node (LN) but rather by reduced maintenance at the site of infection. Consistent with the decreased numbers of Th17 cells in the lungs of infected TLR2-deficient animals, we observed reduced expression of CXCL9, CXCL10 and CXCL11, chemokines involved in recall responses to M. tuberculosis. Our data provides insights into the TLR2 role in infection with M. tuberculosis, with implications in pathophysiology of the disease and vaccine design.Fundação para a Ciência e Tecnologia, Portugal (Project Grants PTDC/SAU/70895/2006 to AGC and PTDC/BIA-BCM/102776/2008 to MS; and Personal Grants SRFH/BD/33034/2006 to MTC; SFRH/BPD/3306/2007 to AC; SFRH/BD/35981/2007 to JC; SFRH/BI/33456/2008 to CS and PTDC/SAU-MII/70895/2006 to DRP) and by the Health Service of Fundação Calouste Gulbenkian. MS is a Ciência 2007 Fellow
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