669 research outputs found

    Enough is Enough: Towards Autonomous Uncertainty-driven Stopping Criteria

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    Autonomous robotic exploration has long attracted the attention of the robotics community and is a topic of high relevance. Deploying such systems in the real world, however, is still far from being a reality. In part, it can be attributed to the fact that most research is directed towards improving existing algorithms and testing novel formulations in simulation environments rather than addressing practical issues of real-world scenarios. This is the case of the fundamental problem of autonomously deciding when exploration has to be terminated or changed (stopping criteria), which has not received any attention recently. In this paper, we discuss the importance of using appropriate stopping criteria and analyse the behaviour of a novel criterion based on the evolution of optimality criteria in active graph-SLAM

    The economic geography of football success: empirical evidence from european cities

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    Introduction. – 1. The geography of successful football teams: an analytical framework – 2. Empirical analysis – 2.1. Data, model estimation and results – 2.2. Cities and teams: some remarks about market size and teams’ performance – 3. Conclusions – 4. Annex

    The production process in basketball: Empirical evidence from Spanish league

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    The main objective of this paper is to provide an empirical assessment of the production process in a basketball team. We estimate a logit model in which the output produced by a team is the game outcome (win or loss) and the inputs are those play characteristics that impact on that outcome. From the results obtained it is clear that, on average, there is a substantial difference between the impact of each play characteristic on a basketball team’s winning probability and that probability varies as the quality/quantity of the inputs used changes, albeit not proportionally.sports economics, team sport, professional basketball, productive process, logit model

    Control of a multi-axis platform for metrological purposes using diferential flatness

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    Positioning and tracking devices with micrometer range and sub-micrometer resolution are becoming of special interest in recent years for an extending range of applications including metrological devices, manipulators and mechanization systems both in research and high precision industries (for example, semiconductors). The control of these systems is not an easy task because of its normally high stiffness and the coupling existing between the different degrees of freedom. The present work proposes a control strategy based on differential flatness for static positioning and dynamic trajectory tracking with a platform of three degrees of freedom. The system uses piezoelectric actuators and is specially conceived for metrological devices, which do not suffer important external loads. The proposed method permits to decouple the design of a closed loop control for each degree of freedom and calculates an open loop command directly from the trajectory definition in the three degrees of freedom. The performance of the controller has been experimentally checked both in positioning and tracking applications

    A visual analytics framework for cluster analysis of DNA microarray data

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    Prova tipográficaCluster analysis of DNA microarray data is an important but difficult task in knowledge discovery processes. Many clustering methods are applied to analysis of data for gene expression, but none of them is able to deal with an absolute way with the challenges that this technology raises. Due to this, many applications have been developed for visually representing clustering algorithm results on DNA microarray data, usually providing dendrogram and heat map visualizations. Most of these applications focus only on the above visualizations, and do not offer further visualization components to the validate the clustering methods or to validate one another. This paper proposes using a visual analytics framework in cluster analysis of gene expression data. Additionally, it presents a new method for finding cluster boundaries based on properties of metric spaces. Our approach presents a set of visualization components able to interact with each other; namely, parallel coordinates, cluster boundary genes, 3D cluster surfaces and DNA microarray visualizations as heat maps. Experimental results have shown that our framework can be very useful in the process of more fully understanding DNA microarray data. The software has been implemented in Java, and the framework is publicly available at http://www. analiticavisual.com/jcastellanos/3DVisualCluster/3D-VisualCluster.This work has been partially funded by the Spanish Ministry of Science and Innovation, the Plan E from the Spanish Government, the European Union from the ERDF (TIN2009-14057-C03-02)

    Intelligent business processes composition based on multi-agent systems

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    This paper proposes a novel model for automatic construction of business processes called IPCASCI (Intelligent business Processes Composition based on multi-Agent systems, Semantics and Cloud Integration). The software development industry requires agile construction of new products able to adapt to the emerging needs of a changing market. In this context, we present a method of software component reuse as a model (or methodology), which facilitates the semi-automatic reuse of web services on a cloud computing environment, leading to business process composition. The proposal is based on web service technology, including: (i) Automatic discovery of web services; (ii) Semantics description of web services; (iii) Automatic composition of existing web services to generate new ones; (iv) Automatic invocation of web services. As a result of this proposal, we have presented its implementation (as a tool) on a real case study. The evaluation of the case study and its results are proof of the reliability of IPCASCI

    Una experiencia docente en la enseñanza del desarrollo orientado a objetos de software utilizando herramientas visuales

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    En este trabajo ofrecemos una visión general de nuestra experiencia impartiendo la asignatura “Desarrollo orientado a objetos de software utilizando herramientas visuales” que se ha comenzado a ofrecer este año en la Facultad de Informática y Estadística de Sevilla. El curso se oferta como asignatura convalidable por créditos de libre configuración y tiene como objetivo fundamental ofrecer a los alumnos una formación de marcado carácter práctico en herramientas y técnicas que son de aplicación habitual dentro de nuestro entorno empresarial

    Three Realizations and Comparison of Hardware for Piezoresistive Tactile Sensors

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    Tactile sensors are basically arrays of force sensors that are intended to emulate the skin in applications such as assistive robotics. Local electronics are usually implemented to reduce errors and interference caused by long wires. Realizations based on standard microcontrollers, Programmable Systems on Chip (PSoCs) and Field Programmable Gate Arrays (FPGAs) have been proposed by the authors for the case of piezoresistive tactile sensors. The solution employing FPGAs is especially relevant since their performance is closer to that of Application Specific Integrated Circuits (ASICs) than that of the other devices. This paper presents an implementation of such an idea for a specific sensor. For the purpose of comparison, the circuitry based on the other devices is also made for the same sensor. This paper discusses the implementation issues, provides details regarding the design of the hardware based on the three devices and compares them

    Interleukin-10 facilitates the selection of patients for systemic thrombolysis

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    Background Clinical-Diffusion mismatch (CDM; NIHSS score ≥8 & DWI lesion volume ≤25 mL) and Perfusion-Diffusion mismatch (PDM; difference >20% between initial DWI and MTT lesion volumes) have been proposed as surrogates for ischemic brains that are at risk of infarction. However, their utility to improve the selection of patients for thrombolytic treatment remains controversial. Our aim was to identify molecular biomarkers that can be used with neuroimaging to facilitate the selection of ischemic stroke patients for systemic thrombolysis. Methods We prospectively studied 595 patients with ischemic stroke within 12 h of the stroke onset. A total of 184 patients received thrombolytic treatment according to the SITS-MOST criteria. DWI and MTT volumes were measured at admission. The main outcome variable was good functional outcome at 3 months (modified Rankin scale <3). Serum levels of glutamate (Glu), IL-10, TNF-α, IL-6, NSE, and active MMP-9 also were determined at admission. Results Patients treated with t-PA who presented with PDM had higher IL-10 levels at admission (p < 0.0001). In contrast, patients with CDM had higher levels of IL-10 (p < 0.0001) as well as Glu and TNF-α (all p < 0.05) and lower levels of NSE and active MMP-9 (all p < 0.0001). IL-10 ≥ 30 pg/mL predicts good functional outcome at 3 months with a specificity of 88% and a sensitibity of 86%. IL-10 levels ≥30 pg/mL independently in both patients with PDM (OR, 18.9) and CDM (OR, 7.5), after an adjustment for covariates. Conclusions Serum levels of IL-10 facilitate the selection of ischemic stroke patients with CDM and PDM for systemic thrombolysis.This project has been partially supported by grants from the Spanish Ministry of Science and Innovation (Fondo de Investigaciones Sanitarias, Instituto Salud Carlos III, RETICS-RD06/0026 and PI081472) and Xunta de Galicia (Consellería de Economía e Industria: 09CSA057918PR, Consellería de Sanidade: PS09/32)S
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