95 research outputs found

    Intelligent Control of a Robotic Arm Using Hierarchical Neural Network Systems

    Get PDF
    Two artificial neural network systems are considered in a hierarchical fashion to plan the trajectory and control of a robotic arm. At the higher level of the hierarchy the neural system consists of four networks: a restricted Coulomb energy network to delineate the robot arm workspace; two standard backpropagation (BP) networks for coordinates transformation; and a fourth network which also uses BP and participates in the trajectory planning by cooperating with other knowledge sources. The control emulation process which is developed using a second neural system at a lower hierarchical level provides the correct sequence of control actions. An example is presented to illustrate the capabilities of the developed architectures

    Hierarchical Neurocontroller Architecture for Robotic Manipulation

    Get PDF
    A hierarchical neurocontroller architecture consisting of two artificial neural network systems for the manipulation of a robotic arm is presented. The higher-level network system participates in the delineation of the robot arm workspace and coordinates transformation and the motion decision-making process. The lower-level network provides the correct sequence of control actions. A straightforward example illustrates the architecture\u27\u27s capabilities, including speed, adaptability, and computational efficienc

    A methodology for realistic space launch risk estimation using information-fusion-based metric

    Get PDF
    In light of the significant changes being observed in the US space industry, in terms of the increase share of commercial launches, the development of inland spaceports, and the emergence of new vehicle designs and propulsion systems, there is need to reassess launch safety. In this paper, several issues related to space launch safety are reviewed, one in particular being the use, as the main the safety metric, of the mean collective risk to the general public, also known as the expectation of casualties. A new, decision level, information-fusion-based metric is proposed, and through a detailed case study, its merit in terms of the quality and quantity of information it generates is illustrated. The need for a new metric is here advocated as a critical first step toward the necessary transition from a risk avoidance philosophy to space launch safety to a risk management philosophy

    Planning and Control of a Robotic Manipulator Using Neural Networks

    Get PDF
    An architecture which utilizes two artificial neural systems for planning and control of a robotic arm is presented. The first neural network system participates in the trajectory planning and the motion decision-making process. The second neural network system provides the correct sequence of control actions with a high accuracy due to the utilization of an unsupervised/supervised neural network scheme. The utilization of a hybrid hierarchical/distributed organization, supervised/unsupervised learning models, and forward modeling yielded an architecture with capabilities of high level functionality

    Psychometric properties of a brief non-verbal test of g factor intelligence

    Get PDF
    Intelligence is the most studied construct in psychology and cognitive neuroscience. In Brazil, the administration of intelligence tests is needed for a number of social rights, including driving privileges. Such requirements have led to a large testing industry but the vast majority of intelligence tests require extended administration times and language skills. In this study, we sought to investigate the psychometric properties and normative results of a new non-verbal intelligence test, the General Matrix of Intelligence (GMI). The GMI is comprised of 28 matrix-based items and can be administered in as little as six-minutes. In this initial pilot test, the GMI was administered to 1,326 participants, ages 15-64 years old (M = 25.65 years, SD = 9.6 years), from all regions in Brazil. These data were analyzed using a 2PL Item Response Theory model, regression analyses were conducted to determine the role of sociodemographic factors, and preliminary norms were computed. Results indicated a unidimensional solution that reproduced the g factor theory, invariance across genders, evidence that cognitively demanding items involving movement or three-dimensional shapes were more difficult than items with less cognitive load, a normal distribution for results, and an interaction between education level and age group in predicting performance. Implications of these findings for research and practice are discussed and all data and codes are provided at https://osf.io/kvu42

    Bradykinin or Acetylcholine as Vasodilators to Test Endothelial Venous Function in Healthy Subjects

    Get PDF
    INTRODUCTION: The evaluation of endothelial function has been performed in the arterial bed, but recently evaluation within the venous system has also been explored. Endothelial function studies employ different drugs that act as endothelium-dependent vasodilatory response inductors. OBJECTIVES: The aim of this study is to compare the endothelium-dependent venous vasodilator response mediated by either acetylcholine or bradykinin in healthy volunteers. METHODS AND RESULTS: Changes in vein diameter after phenylephrine-induced venoconstriction were measured to compare venodilation induced by acetylcholine or bradykinin (linear variable differential transformer dorsal hand vein technique). We studied 23 healthy volunteers; 31% were male, and the subject had a mean age of 33 ± 8 years and a mean body mass index of 23 ± 2 kg/m2. The maximum endothelium-dependent venodilation was similar for both drugs (p = 0.13), as well as the mean responses for each dose of both drugs (r = 0.96). The maximum responses to acetylcholine and bradykinin also had good agreement. CONCLUSION: There were no differences between acetylcholine and bradykinin as venodilators in this endothelial venous function investigation

    Evidence for Reductive Genome Evolution and Lateral Acquisition of Virulence Functions in Two Corynebacterium pseudotuberculosis Strains

    Get PDF
    Ruiz JC, D'Afonseca V, Silva A, et al. Evidence for Reductive Genome Evolution and Lateral Acquisition of Virulence Functions in Two Corynebacterium pseudotuberculosis Strains. PLoS ONE. 2011;6(4): e18551.Background: Corynebacterium pseudotuberculosis, a Gram-positive, facultative intracellular pathogen, is the etiologic agent of the disease known as caseous lymphadenitis (CL). CL mainly affects small ruminants, such as goats and sheep; it also causes infections in humans, though rarely. This species is distributed worldwide, but it has the most serious economic impact in Oceania, Africa and South America. Although C. pseudotuberculosis causes major health and productivity problems for livestock, little is known about the molecular basis of its pathogenicity. Methodology and Findings: We characterized two C. pseudotuberculosis genomes (Cp1002, isolated from goats; and CpC231, isolated from sheep). Analysis of the predicted genomes showed high similarity in genomic architecture, gene content and genetic order. When C. pseudotuberculosis was compared with other Corynebacterium species, it became evident that this pathogenic species has lost numerous genes, resulting in one of the smallest genomes in the genus. Other differences that could be part of the adaptation to pathogenicity include a lower GC content, of about 52%, and a reduced gene repertoire. The C. pseudotuberculosis genome also includes seven putative pathogenicity islands, which contain several classical virulence factors, including genes for fimbrial subunits, adhesion factors, iron uptake and secreted toxins. Additionally, all of the virulence factors in the islands have characteristics that indicate horizontal transfer. Conclusions: These particular genome characteristics of C. pseudotuberculosis, as well as its acquired virulence factors in pathogenicity islands, provide evidence of its lifestyle and of the pathogenicity pathways used by this pathogen in the infection process. All genomes cited in this study are available in the NCBI Genbank database (http://www.ncbi.nlm.nih.gov/genbank/) under accession numbers CP001809 and CP001829

    A list of land plants of Parque Nacional do Caparaó, Brazil, highlights the presence of sampling gaps within this protected area

    Get PDF
    Brazilian protected areas are essential for plant conservation in the Atlantic Forest domain, one of the 36 global biodiversity hotspots. A major challenge for improving conservation actions is to know the plant richness, protected by these areas. Online databases offer an accessible way to build plant species lists and to provide relevant information about biodiversity. A list of land plants of “Parque Nacional do Caparaó” (PNC) was previously built using online databases and published on the website "Catálogo de Plantas das Unidades de Conservação do Brasil." Here, we provide and discuss additional information about plant species richness, endemism and conservation in the PNC that could not be included in the List. We documented 1,791 species of land plants as occurring in PNC, of which 63 are cited as threatened (CR, EN or VU) by the Brazilian National Red List, seven as data deficient (DD) and five as priorities for conservation. Fifity-one species were possible new ocurrences for ES and MG states
    corecore