Improving tracking of trajectories through tracking rate regulation: application to UAVs

The tracking problem (that is, how to follow a previously memorized path) is one of the most important problems in mobile robots. Several methods can be formulated depending on the way the robot state is related to the path. “Trajectory tracking” is the most common method, with the controller aiming to move the robot toward a moving target point, like in a real-time servosystem. In the case of complex systems or systems under perturbations or unmodeled effects, such as UAVs (Unmanned Aerial Vehicles), other tracking methods can offer additional benefits. In this paper, methods that consider the dynamics of the path’s descriptor parameter (which can be called “error adaptive tracking”) are contrasted with trajectory tracking. A formal description of tracking methods is first presented, showing that two types of error adaptive tracking can be used with the same controller in any system. Then, it is shown that the selection of an appropriate tracking rate improves error convergence and robustness for a UAV system, which is illustrated by simulation experiments. It is concluded that error adaptive tracking methods outperform trajectory tracking ones, producing a faster and more robust convergence tracking, while preserving, if required, the same tracking rate when convergence is achieved

A Topologically Consistent Color Digital Image Representation by a Single Tree

A novel, flexible (non-unique) and topologically consistent representation called CRIT (Contour-Region incidence Tree) for a color 2D digital image I is defined here. The CRIT is a tree containing all the inter and intra connectivity information of the constant-color regions. Considering I as an abstract cell complex (ACC), its topological infor mation can be packed as a smaller (in terms of cells) ACC, whose 2-cells are the different constant-color regions of I. This modus operandi over comes the classical connectivity paradoxes of digital images by working with lower-dimensional cells such as 0-cells, 1-cells, and 2-cells. The CRIT structure allows to describe this smaller ACC in a non-redundant way. The proposed technique is based on the previous construction of the Homological Spanning Forest (HSF) structures for encoding homological information of the ACCs canonically associated to I, in terms of rooted trees connecting digital object elements without redundancyMinisterio de Ciencia e Innovación PID2019-110455GB-I00 (Par-HoT

Cambios dimensionales, detectados en telerradiografía de perfil y tomografía computarizada cone-beam, producidos en la vía aérea superior de pacientes adultos post-cirugía ortognática. Revisión sistemática de la literatura

82 P.INTRODUCCIÓN: Son varios los tipos de intervenciones que se realizan en el territorio maxilofacial, en donde la cirugía ortognática ha sido el método que se utiliza más a menudo en deformidades dentofaciales moderadas o severas. El movimiento de los huesos implica cambios en los tejidos blandos adjuntos, generando cambios significativos en la apariencia facial y en las dimensiones del espacio de la vía aérea faríngea. Estas variaciones en las dimensiones pueden ser medidas en cone beam (CBCT) (3D) o en telerradiografía de perfil (TP) (2D). A partir de esto es que se realizó una revisión sistemática de la literatura que busca encontrar relación de los cambios en la vía aérea de pacientes adultos sometidos a cirugía ortognática, que sean detectados en TP y CBCT, según lo reportado por la literatura científica publicada en bases de datos electrónicas desde enero del año 2010 hasta octubre del año 2015. OBJETIVO: Identificar los cambios dimensionales producidos en la VAS post-cirugía ortognática en pacientes adultos, detectados en telerradiografía de perfil y/o tomografía computarizada cone-beam, en literatura publicada desde enero del 2010 hasta octubre de 2015. METODOLOGÍA: Se realizó un protocolo para la realización de una revisión sistemática de la literatura. Este protocolo se registró en el International Prospective Register of Systematic Review y se encuetra disponible en el sitio web http://www.crd.york.ac.uk/http://www.crd.york.ac.uk/PROSPERO/display_record.asp?ID=CRD42015029352. Se realiza una búsqueda principal en los sistemas de bases de datos electrónicos PubMed, Web of Sciences y The Cochrane Library. Y una búsqueda manual adicional en las referencias de artículos analizados a texto completo. Se utilizaron como palabras claves: “Orthognathic Surgery”; “Pharynx”; “Cone-Beam Computed Tomography”; “Cephalometry”. Se incluyeron artículos en idioma español e inglés; revisiones sistemáticas con y sin meta-análisis, ensayos clínicos controlados, estudios de cohorte, estudios de casos y controles; solo estudios realizados en humanos. Se excluyen los artículos que refieran a pacientes con algún síndrome (ejemplo: síndrome apnea obstructiva del sueño), que estén médicamente comprometidos o pacientes fisurados. Todas las fases fueron realizadas por tres evaluadores de forma independiente y las discrepancias fueron resueltas por consenso. RESULTADOS: La estrategia de búsqueda principal arrojó un total de 456 artículos. La búsqueda manual adicional identificó 4 nuevos registros. Se analizan 25 artículos a texto completo. Finalmente sólo se incluyen 12 artículos. CONCLUSIONES: En cirugías de avance maxilar y mandibular, o cada una por sí sola, tanto en CBCT y TP, la vía aérea aumenta. En cirugías de avance maxilar en conjunto con retroceso mandibular, o esta última por sí sola, tanto en CBCT y TP, la vía aérea disminuye. La herramienta CASP evidencia sesgo en la totalidad de los documentos seleccionados en: división de la vía aérea, referencias anatómicas usadas en CBCT o TP, división por género de la muestra, tiempo de seguimiento/control postquirúrgico de los pacientes. Además existen cambios relacionados a la posición del hueso hioides. PALABRAS CLAVES: "Orthognathic Surgery"; "Pharynx"; "Cone-Beam Computed Tomography"; "Cephalometry"/ABSTRACT: INTRODUCTION: There are several types of interventions performed in the maxillofacial territory, where orthognathic surgery has been the method most often used in moderate to severe facial deformities. The movement of the bones involves changes in the accompanying soft tissue, causing significant changes in facial appearance and space dimensions of the pharyngeal airway. These variations in dimensions can be measured in cone beam (CBCT) (3D) or teleradiography profile (TP) (2D). Since this is a systematic review of the literature that seeks to find relation of changes in the airway of adult patients undergoing orthognathic surgery, which are detected in TP and CBCT, as reported by the scientific literature was conducted in electronic databases from January 2010 to October 2015. OBJETIVE: Identify the dimensional changes in the post-orthognathic surgery in adult patients VAS, detected in teleradiography and / or cone-beam computed tomography in literature published from January 2010 to October 2015. METHODOLOGY: Has been made a protocol for conducting a systematic review of the literature. This protocol was recorded in the International Register of Systematic Review Prospective and is available on the website http://www.crd.york.ac.uk/PROSPERO/display_record.asp?ID=CRD42015029352. A main search is performed in the systems of electronic databases PubMed, Web of Sciences and The Cochrane Library. And an additional hand search of references to full-text articles analyzed. They were used as keywords: "Orthognathic Surgery"; "Pharynx"; "Cone-Beam Computed Tomography"; "Cephalometry". Items were included in Spanish and English; systematic reviews with or without meta-analysis, controlled clinical trials, cohort studies, case-control studies; only human studies. Who are medically compromised patients or fissured: items that refer to patients with a syndrome (syndrome obstructive sleep apnea example) are excluded. All phases were carried out by three reviewers independently and discrepancies were resolved by consensus. RESULTS: The primary search strategy yielded a total of 456 items. The additional manual search identified 4 new records. 25 full-text articles are analyzed. Finally only 12 items are included. CONCLUSIONS: In surgeries of maxillary and mandibular advancement, or each one alone, in CBCT and TP, the airway increases. In surgeries maxillary advancement recoil together with mandibular or latter alone, in CBCT and TP, airway decreases. The CASP tool evidence of bias in all selected documents in: division of the airway, anatomical references used in CBCT or TP, gender division of the sample, time tracking / control postsurgical patients. There are also related to the position of the hyoid bone changes. KEYS WORDS: "Orthognathic Surgery"; "Pharynx"; "Cone-Beam Computed Tomography"; "Cephalometry

Parallel Image Processing Using a Pure Topological Framework

Image processing is a fundamental operation in many real time applications, where lots of parallelism can be extracted. Segmenting the image into different connected components is the most known operations, but there are many others like extracting the region adjacency graph (RAG) of these regions, or searching for features points, being invariant to rotations, scales, brilliant changes, etc. Most of these algorithms part from the basis of Tracing-type approaches or scan/raster methods. This fact necessarily implies a data dependence between the processing of one pixel and the previous one, which prevents using a pure parallel approach. In terms of time complexity, this means that linear order O(N) (N being the number of pixels) cannot be cut down. In this paper, we describe a novel approach based on the building of a pure Topological framework, which allows to implement fully parallel algorithms. Concerning topological analysis, a first stage is computed in parallel for every pixel, thus conveying the local neighboring conditions. Then, they are extended in a second parallel stage to the necessary global relations (e.g. to join all the pixels of a connected component). This combinatorial optimization process can be seen as the compression of the whole image to just one pixel. Using this final representation, every region can be related with the rest, which yields to pure topological construction of other image operations. Besides, complex data structures can be avoided: all the processing can be done using matrixes (with the same indexation as the original image) and element-wise operations. The time complexity order of our topological approach for a m×n pixel image is near O(log(m+n)), under the assumption that a processing element exists for each pixel. Results for a multicore processor show very good scalability until the memory bandwidth bottleneck is reached, both for bigger images and for much optimized implementations. The inherent parallelism of our approach points to the direction that even better results will be obtained in other less classical computing architectures.1Ministerio de Economía y Competitividad (España) TEC2012-37868-C04-02AEI/FEDER (UE) MTM2016-81030-PVPPI of the University of Sevill

Building Hierarchical Tree Representations Using Homological-Based Tools

A new algorithm for computing the α-tree hierarchical repre sentation of a grey-scale digital image is presented here. The technique is based on an efficient simplified version of the Homological Spanning For est (HSF) for encoding homological and homotopy-based information of binary digital images. We create one Adjacency Tree (AdjT) for each intensity contrast in a fully parallel manner. These trees, which define a Contrast Adjacency Forest (CAdjF), are in turn transversely intercon nected by another couple of trees: the classical α-tree, and a new one complementing it, called here the α∗-tree. They convey the information of the contours and the flat regions of the original color image, plus the relations between them. Using both the α and α∗-trees, this new topolog ical representation prevents some classical drawbacks that appear when working with a single tree. An implementation in OCTAVE/MATLAB validates the correctness of our algorithm.Ministerio de Ciencia e Innovación PID2019-110455GB-I00 (Par-HoT

On the Topological Disparity Characterization of Square-Pixel Binary Image Data by a Labeled Bipartite Graph

Given an nD digital image I based on cubical n-xel, to fully characterize the degree of internal topological dissimilarity existing in I when using different adjacency relations (mainly, comparing 2n or 2n −1 adjacency relations) is a relevant issue in current problems of digital image processing relative to shape detection or identification. In this paper, we design and implement a new self-dual representation for a binary 2D image I, called {4, 8}-region adjacency forest of I ({4, 8}-RAF, for short), that allows a thorough analysis of the differences between the topology of the 4-regions and that of the 8-regions of I. This model can be straightforwardly obtained from the classical region adjacency tree of I and its binary complement image Ic, by a suitable region label identification. With these two labeled rooted trees, it is possible: (a) to compute Euler number of the set of foreground (resp. background) pixels with regard to 4-adjacency or 8-adjacency; (b) to identify new local and global measures and descriptors of topological dissimilarity not only for one image but also between two or more images. The parallelization of the algorithms to extract and manipulate these structures is complete, thus producing efficient and unsophisticated codes with a theoretical computing time near the logarithm of the width plus the height of an image. Some toy examples serve to explain the representation and some experiments with gray real images shows the influence of the topological dissimilarity when detecting feature regions, like those returned by the MSER (maximally stable extremal regions) method.Ministerio de Economía, Industria y Competitividad PID2019-110455GB-I00 (Par-HoT)Junta de Andalucía US-138107

Robotic System for Inspection by Contact of Bridge Beams Using UAVs

This paper presents a robotic system using Unmanned Aerial Vehicles (UAVs) for bridge-inspection tasks that require physical contact between the aerial platform and the bridge surfaces, such as beam-deflection analysis or measuring crack depth with an ultrasonic sensor. The proposed system takes advantage of the aerodynamic ceiling effect that arises when the multirotor gets close to the bridge surface. Moreover, this paper describes how a UAV can be used as a sensor that is able to fly and touch the bridge to take measurements during an inspection by contact. A practical application of the system involving the measurement of a bridge’s beam deflection using a laser tracking station is also presented. In order to validate our system, experiments on two different bridges involving the measurement of the deflection of their beams are shown.Ministerio de Economia, Industria, y Competitividad DPI2015-71524-RComisión Europea H2020-ICT-2015-687384Comisión Europea H2020-MG-2017-76906

Versatilidad y eficiencia de los autómatas celulares para la simulación y análisis de sistemas complejos en Ingeniería

Los autómatas celulares se componen de un conjunto de celdas (generalmente simples) interactuantes que evolucionan en pasos discretos, formando un sistema dinámico. Sus aplicaciones son múltiples y en muy diversos campos, no sólo dentro de la ingeniería sino dentro de las ciencias sociales, la economía, la biología, o las ciencias en general. Actualmente son una de las mejores maneras de simular un problema espacio-temporal, donde la vecindad y colaboración entre agentes (celdas) sea clave y resulte finalmente en uno o varios fenómenos emergentes. Además, su ventaja es que son intrínsicamente paralelos, permitiendo predecir el comportamiento de sistemas complejos con entradas diversas en muy poco tiempo, al poder repartirlos fácilmente en múltiples procesadores o en GPUs (Graphic Processing Units).Ministerio de Ciencia e Innovación y los fondos AEI/FEDER (EU) TIN2017-89842-P (MABICAP)Ministerio de Ciencia e Innovación y los fondos AEI/FEDER (EU) PID2019-110455GB-I00 (Par-HoT)Ministerio de Ciencia e Innovación y los fondos AEI/FEDER (EU) US-1381077 (CIUCAP-HSF

Use of Monoclonal Antibodies in Immunocompromised Patients Hospitalized with Severe COVID-19: A Retrospective Multicenter Cohort

This work was supported by the Research Institute Puerta de Hierro-Segovia de Aranda (IDIPHSA), funding number 0040200108 (2.400€).Objective: We aim to describe the safety and efficacy of sotrovimab in severe cases of COVID-19 in immunocompromised hosts. Methods: We used a retrospective multicenter cohort including immunocompromised hospitalized patients with severe COVID-19 treated with sotrovimab between October 2021 and December 2021. Results: We included 32 patients. The main immunocompromising conditions were solid organ transplantation (46.9%) and hematological malignancy (37.5%). Seven patients (21.9%) had respiratory progression: 12.5% died and 9.4% required mechanical ventilation. Patients treated within the first 14 days of their symptoms had a lower progression rate: 12.0% vs. 57.1%, p = 0.029. No adverse event was attributed to sotrovimab. Conclusions: Sotrovimab was safe and may be effective in its use for immunocompromised patients with severe COVID-19. More studies are needed to confirm these preliminary data.Depto. de MedicinaFac. de MedicinaTRUEResearch Institute Puerta de Hierro-Segovia de Aranda (IDIPHSA)pu