Reinforcement learning in a multi-agent framework for pedestrian simulation

El objetivo de la tesis consiste en la utilización de Aprendizaje por refuerzo (Reinforcement Learning) para generar simulaciones plausibles de peatones en diferentes entornos. Metodología Se ha desarrollado un marco de trabajo multi-agente donde cada agente virtual que aprende un comportamiento de navegación por interacción con el mundo virtual en el que se encuentra junto con el resto de agentes. El mundo virtual es simulado con un motor físico (ODE) que está calibrado con parámetros de peatones humanos extraídos de la bibliografía de la materia. El marco de trabajo es flexible y permite utilizar diferentes algoritmos de aprendizaje (en concreto Q-Learning y Sarsa(lambda) en combinación con diferentes técnicas de generalización del espacio de estados (en concreto cuantización Vectorial y tile coding). Como herramientas de análisis de los comportamientos aprendidos se utilizan diagramas fundamentales (relación velocidad/densidad), mapas de densidad, cronogramas y rendimientos (en términos del porcentaje de agentes que consiguen llegar al objetivo). Conclusiones: Tras una batería de experimentos en diferentes escenarios (un total de 6 escenarios distintos) y los correspondientes analisis de resultados, las conclusiones son las siguientes: - Se han conseguido comportamientos plausibles de peatones -Los comportamientos son robustos al escalado y presentan capacidades de abstracción (comportamientos a niveles táctico y de planificación) -Los comportamientos aprendidos son capaces de generar comportamientos colectivos emergentes -La comparación con otro modelo de peatones estandar (Modelo de Helbing) y los análisis realizados a nivel de diagramas fundamentales, indican que la dinámica aprendida es coherente y similar a una dinámica de peatones

Using Inverse Reinforcement Learning with Real Trajectories to Get More Trustworthy Pedestrian Simulation

Reinforcement learning is one of the most promising machine learning techniques to get intelligent behaviors for embodied agents in simulations. The output of the classic Temporal Difference family of Reinforcement Learning algorithms adopts the form of a value function expressed as a numeric table or a function approximator. The learned behavior is then derived using a greedy policy with respect to this value function. Nevertheless, sometimes the learned policy does not meet expectations, and the task of authoring is difficult and unsafe because the modification of one value or parameter in the learned value function has unpredictable consequences in the space of the policies it represents. This invalidates direct manipulation of the learned value function as a method to modify the derived behaviors. In this paper, we propose the use of Inverse Reinforcement Learning to incorporate real behavior traces in the learning process to shape the learned behaviors, thus increasing their trustworthiness (in terms of conformance to reality). To do so, we adapt the Inverse Reinforcement Learning framework to the navigation problem domain. Specifically, we use Soft Q-learning, an algorithm based on the maximum causal entropy principle, with MARL-Ped (a Reinforcement Learning-based pedestrian simulator) to include information from trajectories of real pedestrians in the process of learning how to navigate inside a virtual 3D space that represents the real environment. A comparison with the behaviors learned using a Reinforcement Learning classic algorithm (Sarsa(λ)) shows that the Inverse Reinforcement Learning behaviors adjust significantly better to the real trajectories

Peritoneal Dissemination of Hepatoid Carcinoma of the Ovary Treated with Cytoreductive Surgery and Hyperthermic Intraoperative Intraperitoneal Chemotherapy

Hepatoid carcinoma of the ovary (HCO) was first reported in 1987 in 5 cases of malignant ovarian tumors which were similar to hepatocarcinoma in the histological analysis. We report the first case in the literature of a patient diagnosed with HCO treated using HIPEC after extensive cytoreductive surgery, and we discuss the value of this therapeutical option in patients with HCO

Placebo-controlled trial of nimodipine in the treatment of acute ischemic cerebral infarction

Nimodipine is a 1,4-dihydropyridine derivative that shows a preferential cerebrovascular activity in experimental animals. Clinical data suggest that nimodipine has a beneficial effect on the neurologic outcome of patients suffering an acute ischemic stroke. Our double-blind placebo-controlled multicenter trial was designed to assess the effects of oral nimodipine on the mortality rate and neurologic outcome of patients with an acute ischemic stroke. One hundred sixty-four patients were randomly allocated to receive either nimodipine tablets (30 mg q.i.d.) or identical placebo tablets for 28 days. Treatment was always started less than or equal to 48 hours after the acute event. The Mathew Scale, slightly modified by Gelmers et al, was used for neurologic assessment. Mortality rate and neurologic outcome after 28 days were used as evaluation criteria. We considered 123 patients to be valid for the analysis of efficacy. Mortality rates did not differ significantly between groups. Neurologic outcome after 28 days of therapy did not differ between groups. However, when only those patients most likely to benefit from any intervention (Mathew Scale sum score of less than or equal to 65 at baseline) were analyzed separately in post hoc-defined subgroups, the nimodipine-treated subgroups showed a significantly better neurologic outcome. This result suggests that some patients with acute ischemic stroke will benefit from treatment with nimodipine tablets

Administración de servicios de Internet. De la teoría a la práctica

El principal objetivo de este libro se centra en exponer y organizar los diferentes conceptos, tecnologías, modelos y herramientas involucrados en el ámbito del desarrollo de sistemas distribuidos en Internet. El libro está organizado en dos grandes secciones: Servicios de red y Servicios avanzados para la red. La primera parte está dedicada a los conceptos y tecnologías asociados con la implantación de aplicaciones distribuidas. Los casos prácticos están más orientados a administradores de sistemas. La segunda parte está dedicada a servicios que suelen proporcionar soporte, no a los usuarios finales, sino a otras aplicaciones y servicios de red

Full-wave analysis and design of broadband turnstile junctions

The efficient design of broadband turnstile junctions compensated with piled-up cylindrical metallic posts is discussed in this contribution. Very high relative bandwidths can be obtained, while maintaining the diameter of the input circular access port lower than the width of the rectangular waveguide ports, thus reducing the number of excited higher order circular waveguide modes. A novel full-wave analysis tool has also been implemented in order to reduce the CPU effort related to the complete design process.San Blas Oltra, ÁA.; Pérez Soler, FJ.; Gil Raga, J.; Mira Pérez, FE.; Boria Esbert, VE.; Gimeno Martinez, B. (2011). Full-wave analysis and design of broadband turnstile junctions. Progress In Electromagnetics Research Letters. 24:149-158. doi:10.2528/PIERL11051703S1491582

Highly efficient full-wave electromagnetic analysis of 3D arbitrarily-shaped waveguide microwave devices using an integral equation technique

A novel technique for the full-wave analysis of 3-D complex waveguide devices is presented. This new formulation, based on the Boundary Integral-Resonant Mode Expansion (BI-RME) method, allows the rigorous full-wave electromagnetic characterization of 3-D arbitrarily shaped metallic structures making use of extremely low CPU resources (both time and memory). The unknown electric current density on the surface of the metallic elements is represented by means of Rao-Wilton-Glisson basis functions, and an algebraic procedure based on a singular value decomposition is applied to transform such functions into the classical solenoidal and nonsolenoidal basis functions needed by the original BI-RME technique. The developed tool also provides an accurate computation of the electromagnetic fields at an arbitrary observation point of the considered device, so it can be used for predicting high-power breakdown phenomena. In order to validate the accuracy and efficiency of this novel approach, several new designs of band-pass waveguides filters are presented. The obtained results (S-parameters and electromagnetic fields) are successfully compared both to experimental data and to numerical simulations provided by a commercial software based on the finite element technique. The results obtained show that the new technique is specially suitable for the efficient full-wave analysis of complex waveguide devices considering an integrated coaxial excitation, where the coaxial probes may be in contact with the metallic insets of the component.This work was supported by the Ministerio de Economia y Competitividad, Spanish Government, under the Research Projects TEC2013-47037-C5-1-R and TEC2013-47037-C5-4-R.Vidal Pantaleoni, A.; San Blas Oltra, ÁA.; Quesada Pereira, FD.; Pérez Soler, FJ.; Gil Raga, J.; Vicente Quiles, CP.; Gimeno Martinez, B.... (2015). Highly efficient full-wave electromagnetic analysis of 3D arbitrarily-shaped waveguide microwave devices using an integral equation technique. Radio Science. 50(7):642-655. https://doi.org/10.1002/2015RS005685S64265550

¿La evaluación evoluciona? Una experiencia de coevaluación en ABP

Desde hace 8 años, el grado de Ingeniería Multimedia imparte el 4º curso utilizando Aprendizaje Basado en Proyectos (ABP) e integrando a todas las asignaturas en él. El programa ha tenido mucho éxito, pero siempre ha acusado un problema, la evaluación. Al tratarse de un trabajo en grupo altamente colaborativo, que integra a todas las asignaturas del curso y que durante los dos semestres trabaja en un único gran proyecto, es muy difícil discernir el trabajo real realizado por cada componente del equipo, produciéndose descompensaciones o incluso malas prácticas. Durante años, se ha tratado de adoptar medidas para paliar esta situación, pero persisten algunas disfunciones. Para solucionarlo, hemos diseñado e implantado una metodología de coevaluación, alineada con la gestión del programa ABP y que persigue dos objetivos: procurar un reparto de nota asociado con el esfuerzo individual realizado, basado en información objetiva y cuantificable, junto con una evaluación formativa y sumativa justa; y desarrollar las habilidades blandas imprescindibles hoy en día en entornos de trabajo colaborativos. En este artículo presentamos la herramienta de coevaluación desarrollada, la valoración realizada sobre la herramienta por las/os participantes en la experiencia y exalumnos de años anteriores, y los resultados obtenidos hasta la fecha.For the last 8 years, the Multimedia Engineering degree has been teaching the 4th year using Project Based Learning (PBL) and integrating all the subjects in it. The program has been very successful, but there has always been one problem: assessment. As it is a highly collaborative group work, integrating all the subjects of the course and working on a single large project during the two semesters, it is very difficult to discern the real work done by each member, causing imbalances or even malpractice. For years, we have tried to adopt measures to mitigate this situation, but without any positive results. To solve this problem, we have designed and implemented a co-evaluation methodology, aligned with the PBL program management, which has two objectives: to ensure a distribution of points associated with the individual effort, based on objective and measurable information, together with a fair formative and summative evaluation; and to develop the soft skills that are essential in current collaborative work environments. In this article we present the co-evaluation tool developed, the assessment made of the tool by the participants in the experience and alumni from previous years, and the results obtained to date.El presente trabajo ha contado con una ayuda del Programa de Redes de investigación en docencia universitaria del Instituto de Ciencias de la Educación de la Universidad de Alicante (convocatoria 2021-22). Ref.: 5490, Diseño y desarrollo de una metodología y plataforma TIC para coevaluación en ABP

Lipid profile, cardiovascular disease and mortality in a Mediterranean high-risk population: The ESCARVAL-RISK study.

The potential impact of targeting different components of an adverse lipid profile in populations with multiple cardiovascular risk factors is not completely clear. This study aims to assess the association between different components of the standard lipid profile with all-cause mortality and hospitalization due to cardiovascular events in a high-risk population. This prospective registry included high risk adults over 30 years old free of cardiovascular disease (2008-2012). Diagnosis of hypertension, dyslipidemia or diabetes mellitus was inclusion criterion. Lipid biomarkers were evaluated. Primary endpoints were all-cause mortality and hospital admission due to coronary heart disease or stroke. We estimated adjusted rate ratios (aRR), absolute risk differences and population attributable risk associated with adverse lipid profiles. 51,462 subjects were included with a mean age of 62.6 years (47.6% men). During an average follow-up of 3.2 years, 919 deaths, 1666 hospitalizations for coronary heart disease and 1510 hospitalizations for stroke were recorded. The parameters that showed an increased rate for total mortality, coronary heart disease and stroke hospitalization were, respectively, low HDL-Cholesterol: aRR 1.25, 1.29 and 1.23; high Total/HDL-Cholesterol: aRR 1.22, 1.38 and 1.25; and high Triglycerides/HDL-Cholesterol: aRR 1.21, 1.30, 1.09. The parameters that showed highest population attributable risk (%) were, respectively, low HDL-Cholesterol: 7.70, 11.42, 8.40; high Total/HDL-Cholesterol: 6.55, 12.47, 8.73; and high Triglycerides/HDL-Cholesterol: 8.94, 15.09, 6.92. In a population with cardiovascular risk factors, HDL-cholesterol, Total/HDL-cholesterol and triglycerides/HDL-cholesterol ratios were associated with a higher population attributable risk for cardiovascular disease compared to other common biomarkers.S