Ontología para planificación lineal

Como consecuencia de la ineficiencia potencial de la planificación lineal manifestada en el excesivo retroceso durante la búsqueda en algunos de los primeros sistemas planificadores lineales, este tipo de planificación había quedado relegado a un segundo plano como herramienta de propósito general. Recientemente, sin embargo, se ha reabierto el debate al incluirse un nuevo elemento de juicio: la mayor capacidad de expresión en la codificación de los dominios, lo que facilita la implementación de conocimiento específico para guiar la búsqueda, al desarrollarse ésta en un espacio de estados. En esta tesis se ha continuado esta línea de investigación, aportando un marco formalizador para la representación de conocimiento específico en dominios de planificación clásica. Se propone una metodología innovadora de propósito general que se ha denominado ESPLAN (EStrategias para PLANificación), para capturar el conocimiento específico en los términos del experto en el dominio. A tal fin, el planificador ESPLAN debe poder representar intuiciones, posiblemente incompletas, aprovechar nuevas oportunidades que se presenten y recuperarse de errores en su propia base de conocimiento, durante la planificación. Esta metodología aportada ESPLAN se fundamenta en una nueva ontología que utiliza la noción estrategia para construir jerarquías, de forma similar a lo que ocurre en la planificación HTN. A diferencia de las tareas HTN, se ha previsto para las estrategias que puedan ser incompletas y que puedan transmitir información durante los retrocesos. Las estrategias conforman la base de conocimiento del planificador ESPLAN que se encuentra en un plano superior a las acciones concretas, lo que permite diseñar la Teoría de Estrategias para el dominio, de forma totalmente independiente de la posterior representación de las acciones. La ontología se complementa con un nuevo algoritmo de planificación que introduce una búsqueda de oportunidades y de contingencia innovadora, que se solapa con la búsqueda convencional. Se definen además los elementos necesarios para controlar la complejidad añadida, así como condiciones operativas para su uso. En esta tesis el modelado ESPLAN se ha aplicado al ajedrez, dominio éste en el que normalmente no se ha utilizado la perspectiva de la planificación. En este dominio complejo se ha definido aquí una Teoría de Estrategias lo suficientemente representativa para realizar búsquedas totalmente guiadas por estrategias en algunas posiciones prototipo, en el que el conocimiento existente permite dirigir la búsqueda completamente. Se han construido varios demostradores. Uno de ellos, además de validar la metodología propuesta en el dominio del ajedrez, tiene la suficiente entidad como para ser un verdadero banco de pruebas que permita, en un futuro próximo, incorporar cada vez más conocimiento heurístico a este dominio, en términos similares a los que emplean los Grandes Maestros

A PDDL-based simulation system

This paper presents a planning simulation system that allows automated planning practitioners to experiment with planning domains, defined using the PDDL language. The proposed system has a modular architecture including a SAT planner (PDDL parser, SAT encoder and SAT solver), a plan simulator and a 3D view user interface. Most of these modules can be changed with other with similar purpose. This system allows users to test and validate PDDL domains and solutions, using an attractive user interface that includes the simulation of the execution of the plan on a 3D view as an animation

Computation of the optimal relative pose between overlapping grid maps through discrepancy minimization

Grid maps are a common environment representation in mobile robotics. Many Simultaneous Localization and Mapping (SLAM) solutions divide the global map into submaps, forming some kind of graph or tree to represent the structure of the environment, while the metric details are captured in the submaps. This work presents a novel algorithm that is able to compute a physically feasible relative pose between two overlapping grid maps. Our algorithm can be used for correspondence search (data association), but also for integrating negative information in a unified way. This paper proposes a discrepancy measure between two overlapping grid maps and its application in a quasi Newton optimization algorithm, with the hypothesis that minimizing such discrepancy could provide useful information for SLAM. Experimental evidence is provided showing the high potential of the algorithm

Fast processing of grid maps using graphical multiprocessors

Grid mapping is a very common technique used in mobile robotics to build a continuous 2D representation of the environment useful for navigation purposes. Although its computation is quite simple and fast, this algorithm uses the hypothesis of a known robot pose. In practice, this can require the re-computation of the map when the estimated robot poses change, as when a loop closure is detected. This paper presents a parallelization of a reference implementation of the grid mapping algorithm, which is suitable to be fully run on a graphics card showing huge processing speedups (up to 50×) while fully releasing the main processor, which can be very useful for many Simultaneous Localization and Mapping algorithms

Building maps of large environments using splines and geometric analysis

Recently, a novel solution to the Simultaneous Localization and Map building (SLAM) problem for complex indoor environments was presented, using a set of splines for describing the geometries detected by a laser range finder mounted on a mobile platform. In this paper, a method for exploiting the geometric information underlying in these maps in the data association process is described. The proposed approach uses graphs of relations between simple features extracted from the environment, and a bit encoded implementation for obtaining a maximum clique that relates observations with previously visited areas. This information is used to update the relative positions of a collage of submaps of limited size

SITED: Un laboratorio interactivo y portable de electrónica digital

Esta comunicación presenta un dispositivo que, conectado a un ordenador a través de un puerto USB, convierte el conjunto en una plataforma interactiva para la realización de prácticas básicas de Electrónica Digital, que hemos dado en llamar SITED, acrónimo de Sistema Interactivo Tutor de Electrónica Digital. Este sistema es una evolución de otro diseño anterior, que se denominó ETED (Entrenador Tutor de Electrónica Digital), con el que se ha obtenido una mejora de las actividades prácticas que se desarrollan en el Laboratorio de la asignatura “Electrónica Digital

An improved bit parallel exact maximum clique algorithm

This paper describes new improvements for BB-MaxClique (San Segundo et al. in Comput Oper Resour 38(2):571–581, 2011 ), a leading maximum clique algorithm which uses bit strings to efficiently compute basic operations during search by bit masking. Improvements include a recently described recoloring strategy in Tomita et al. (Proceedings of the 4th International Workshop on Algorithms and Computation. Lecture Notes in Computer Science, vol 5942. Springer, Berlin, pp 191–203, 2010 ), which is now integrated in the bit string framework, as well as different optimization strategies for fast bit scanning. Reported results over DIMACS and random graphs show that the new variants improve over previous BB-MaxClique for a vast majority of cases. It is also established that recoloring is mainly useful for graphs with high densities

Learning of the Object Oriented Paradigm Through Interactive Video-Games Development

The Object Orientation Paradigm (OOP) is more than Object Oriented languages. Learning the syntax of a language as C++ or Java is a relatively easy task compared with the understanding of the principles of OO Modeling and Design (OOD), which require a high ability of abstract reasoning. Moreover, it is not enough to teach the artifacts of Computer Aided Software Engineering (CASE) as the Unified Modeling Language (UML) if those principles are not properly understood. We wanted to engage the students in a motivating framework, so both the principles of OOD are properly acquired and put in practice with CASE and programming tools

Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

Summary Background Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. Methods We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung’s disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. Findings We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung’s disease) from 264 hospitals (89 in high-income countries, 166 in middleincome countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in lowincome countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. Interpretation Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between lowincome, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030

A novel clique formulation for the visual feature matching problem

© 2015, Springer Science+Business Media New York. This paper presents CCMM (acronym for image Clique Matching), a new deterministic algorithm for the visual feature matching problem when images have low distortion. CCMM is multi-hypothesis, i.e. for each feature to be matched in the original image it builds an association graph which captures pairwise compatibility with a subset of candidate features in the target image. It then solves optimum joint compatibility by searching for a maximum clique. CCMM is shown to be more robust than traditional RANSAC-based single-hypothesis approaches. Moreover, the order of the graph grows linearly with the number of hypothesis, which keeps computational requirements bounded for real life applications such as UAV image mosaicing or digital terrain model extraction. The paper also includes extensive empirical validation.This work is funded by the Spanish Ministry of Economy and Competitiveness (ARABOT: DPI 2010-21247-C02-01) and supervised by CACSA whose kindness we gratefully acknowledge.Peer Reviewe