SLAM using an Imaging Sonar for Partially Structured Underwater Environments

In this paper we describe a system for underwater navigation with AUVs in partially structured environments, such as dams, ports or marine platforms. An imaging sonar is used to obtain information about the location of planar structures present in such environments. This information is incorporated into a feature-based SLAM algorithm in a two step process: (I) the full 360deg sonar scan is undistorted (to compensate for vehicle motion), thresholded and segmented to determine which measurements correspond to planar environment features and which should be ignored; and (2) SLAM proceeds once the data association is obtained: both the vehicle motion and the measurements whose correct association has been previously determined are incorporated in the SLAM algorithm. This two step delayed SLAM process allows to robustly determine the feature and vehicle locations in the presence of large amounts of spurious or unrelated measurements that might correspond to boats, rocks, etc. Preliminary experiments show the viability of the proposed approach

Diagnosi multifuncional de la conca de la riera de Santa Coloma

Estudi de la qualitat de l’aigua de la riera de Santa Coloma i el seu paper dins la connectivitat multifuncional de la comarca de la Selva. La riera és l’eix fluvial principal de la subconca més important de la Tordera i el seu curs abraça gran part de la comarca. Per avaluar la qualitat de l’aigua s’han fet anàlisis amb paràmetres fisicoquímics i biològics. Per a l’estudi de la connectivitat s’ha fet un anàlisi a nivell local (barreres transversals a la llera i QBR) i a nivell regional identificant les principals amenaces per a la connectivitat ecològica i paisatgística (col.lisions d’ungulats o punts negres, fitxes de punts crítics, entre d’altres). S’arriba a la conclusió que la riera no té una bona qualitat de l’aigua (en alguns casos hi ha eutrofització), el seu bosc de ribera està molt degradat (sobretot a la part baixa del curs) i finalment, hi ha un gran nombre d’espais amb una gran importància estratègica per a la connectivitat però que alhora pateixen fortes pressions antròpiques per les infraestructures lineals, les quals a més, redueixen la permeabilització ecològica i fins i tot, provoquen col.lisions amb ungulats

Diagnosi de les potencialitats silvoramaderes per a la prevenció d’incendis forestals a Fitor (EIN Gavarres)

Diagnosi ambiental de la zona de Fitor (EIN Gavarres) per tal de gestionar aquesta zona, reduint el risc d’ incendi forestal. Amb l’ objectiu de reduir el risc d’ incendi en aquesta zona es proposa la introducció d’ un ramat de 350 individus per rebaixar la fitomassa del sotabosc, tenint en compte els PEG’s (Punts Estratègics de Gestió) marcats en el PPIF (Pla de Prevenció d’ Incendis Forestals). Es proposen una sèrie de recorreguts i àrees de pastura per tal de reduir o mantenir la fitomassa del sotabosc, i unes propostes d’actuació a nivell executiu i divulgatiu per dinamitzar el sector ramader

Diagnosi ambiental d'oportunitats de minimització a l'Ajuntament de Banyoles

Aplicació d'una DAOM (Diagnosi Ambiental d’Oportunitats de Minimització)a l'Ajuntament de Banyoles. Una DAOM és una eina desenvolupada pel Centre per a l’Empresa i el Medi Ambient, que consisteix en l’avaluació d’una activitat o procés, per determinar les possibles oportunitats de prevenció i reducció en origen de la contaminació, i aportar-hi alternatives d’actuació tècnica i econòmicament viables

Mophological analysis of the human vasculature from medical imaging. Application to cerebral and coranary arteries

In this project, we have investigated new ways of modelling and analysis of human vasculature from Medical images. The research was divided in two main areas: cerebral vasculature analysis and coronary arteries modeling. Regarding cerebral vasculature analysis, we have studed cerebral aneurysms, internal carotid and the Circle of Willis (CoW). Aneurysms are abnormal vessel enlargements that can rupture causing important cerebral damages or death. The understanding of this pathology, together with its virtual treatment, and image diagnosis and prognosis, includes identification and detailed measurement of the aneurysms. In this context, we have proposed two automatic aneurysm isolation method, to separate the abnormal part of the vessel from the healthy part, to homogenize and speed-up the processing pipeline usually employed to study this pathology, [Cardenes2011TMI, arrabide2011MedPhys]. The results obtained from both methods have been also compared and validatied in [Cardenes2012MBEC]. A second important task here the analysis of the internal carotid [Bogunovic2011Media] and the automatic labelling of the CoW, Bogunovic2011MICCAI, Bogunovic2012TMI]. The second area of research covers the study of coronary arteries, specially coronary bifurcations because there is where the formation of atherosclerotic plaque is more common, and where the intervention is more challenging. Therefore, we proposed a novel modelling method from Computed Tomography Angiography (CTA) images, combined with Conventional Coronary Angiography (CCA), to obtain realistic vascular models of coronary bifurcations, presented in [Cardenes2011MICCAI], and fully validated including phantom experiments in [Cardene2013MedPhys]. The realistic models obtained from this method are being used to simulate stenting procedures, and to investigate the hemodynamic variables in coronary bifurcations in the works submitted in [Morlachi2012, Chiastra2012]. Additionally, another preliminary work has been done to reconstruct the coronary tree from rotational angiography, and published in [Cardenes2012ISBI].

Characterization of myocardial deformation in patients with different etiologies of left ventricular hypertrophy by using strain distribution from Magnetic Resonance Imaging

Introducción y objetivos. Se ha señalado que, en la miocardiopatía hipertrófica (MCH), la desorganización de las fibras regionales da lugar a segmentos en los que la deformación es nula o está gravemente reducida, y que estos segmentos tienen una distribución no uniforme en el ventrículo izquierdo (VI). Esto contrasta con lo observado en otros tipos de hipertrofia como en el corazón de atleta o la hipertrofia ventricular izquierda hipertensiva (HVI-HT), en los que puede haber una deformación cardiaca anormal, pero nunca tan reducida como para que se observe ausencia de deformación. Así pues, proponemos el empleo de la distribución de los valores de strain para estudiar la deformación en la MCH. Métodos. Con el empleo de resonancia magnética marcada (tagged), reconstruimos la deformación sistólica del VI de 12 sujetos de control, 10 atletas, 12 pacientes con MCH y 10 pacientes con HVI-HT. La deformación se cuantificó con un algoritmo de registro no rígido y determinando los valores de strain sistólico máximo radial y circunferencial en 16 segmentos del VI. Resultados. Los pacientes con MCH presentaron unos valores medios de strain significativamente inferiores a los de los demás grupos. Sin embargo, aunque la deformación observada en los individuos sanos y en los pacientes con HVI-HT se concentraba alrededor del valor medio, en la MCH coexistían segmentos con contracción normal y segmentos con una deformación nula o significativamente reducida, con lo que se producía una mayor heterogeneidad de los valores de strain. Se observaron también algunos segmentos sin deformación incluso en ausencia de fibrosis o hipertrofia. Conclusiones. La distribución de strain caracteriza los patrones específicos de deformación miocárdica en pacientes con diferentes etiologías de la HVI. Los pacientes con MCH presentaron un valor medio de strain significativamente inferior, así como una mayor heterogeneidad de strain (en comparación con los controles, los atletas y los pacientes con HVI-HT), y tenían regiones sin deformación.

Diagnosi de necessitats socials i educatives de l'aula multilingüe: aproximació des del cas de matemàtiques

El nostre objectiu principal ha estat estudiar el desenvolupament de competències discursives de l’alumnat (d’origen) estranger que contribueixin a entendre i atendre les seves necessitats socials i educatives a l’aula (de matemàtiques) multilingüe. Amb aquesta intenció, hem dut a terme accions científiques a dos nivells: amb professorat i amb estudiants. Quant a la caracterització de la complexitat normativa de l’aula de matemàtiques multilingüe, tal com estava previst: 1) hem exemplificat diverses normes socials i lingüístiques existents en el desenvolupament de pràctiques matemàtiques a l’aula; i 2) hem particularitzat el fenomen de la diversitat de normes socials i lingüístiques en casos de sessions de classe de secundària. Quant a la documentació d'indicadors de progrés en la comprensió de normes socials i lingüístiques de l’aula, i en el desenvolupament de competències discursives d’adequació a aquestes normes, tal com estava previst: 1) hem caracteritzat estratègies d’ensenyament i aprenentatge de normes socials i lingüístiques en situacions d’interacció social en petit i gran grup; i 2) hem construït criteris de seguiment del grau de desenvolupament de competències discursives d’adequació a les normes, tant pel que a professorat com alumnat. Finalment, quant a l'anàlisi de la contribució de les competències discursives a la construcció d’identitats socials, lingüístiques i matemàtiques compartides: 1) hem estudiat els usos que l’estudiant (d’origen) estranger fa de normes escolars vinculades a pràctiques socials, lingüístiques i matemàtiques; i 2) hem examinat la construcció de significats socials, lingüístics i matemàtics compartits en un ampli ventall de processos d’adequació a normes de l’aula orquestrades pel professorat de la nostra mostra.

MSISpIC: A Probabilistic Scan Matching Algorithm Using a Mechanical Scanned Imaging Sonar

This paper compares two well known scan matching algorithms: the MbICP and the pIC. As a result of the study, it is proposed the MSISpIC, a probabilistic scan matching algorithm for the localization of an Autonomous Underwater Vehicle (AUV). The technique uses range scans gathered with a Mechanical Scanning Imaging Sonar (MSIS), and the robot displacement estimated through dead-reckoning with the help of a Doppler Velocity Log (DVL) and a Motion Reference Unit (MRU). The proposed method is an extension of the pIC algorithm. Its major contribution consists in: 1) using an EKF to estimate the local path traveled by the robot while grabbing the scan as well as its uncertainty and 2) proposing a method to group into a unique scan, with a convenient uncertainty model, all the data grabbed along the path described by the robot. The algorithm has been tested on an AUV guided along a 600m path within a marina environment with satisfactory results

Diagnostic imaging modalities of osteoblastic metastases

Methods to quantify radiograph images are needed to improve the identification of metastases

Imaging the seascapes of the Mediterranean

The Mediterranean Sea is a relative newcomer to Earth"s landscape. Due to its complex tectonic history, this mid-latitude sea is composed of a cluster of basins. Their seascape is in most cases dominated by geologically young structures, but also by sedimentary processes. Among the latter, sedimentary processes related to the dynamics of the largest rivers in the Mediterranean (Ebro, Rhône, Po, Danube, and Nile) stand out. This overview article illustrates the main sedimentary processes and their products contributing to shape the Mediterranean seascape within a source-tosink approach. To highlight this approach, this article mainly focuses on one of the EUROSTRATAFORM project study areas: the northwestern Mediterranean.

Model-Free Reconstruction of Excitatory Neuronal Connectivity from Calcium Imaging Signals

A systematic assessment of global neural network connectivity through direct electrophysiological assays has remained technically infeasible, even in simpler systems like dissociated neuronal cultures. We introduce an improved algorithmic approach based on Transfer Entropy to reconstruct structural connectivity from network activity monitored through calcium imaging. We focus in this study on the inference of excitatory synaptic links. Based on information theory, our method requires no prior assumptions on the statistics of neuronal firing and neuronal connections. The performance of our algorithm is benchmarked on surrogate time series of calcium fluorescence generated by the simulated dynamics of a network with known ground-truth topology. We find that the functional network topology revealed by Transfer Entropy depends qualitatively on the time-dependent dynamic state of the network (bursting or non-bursting). Thus by conditioning with respect to the global mean activity, we improve the performance of our method. This allows us to focus the analysis to specific dynamical regimes of the network in which the inferred functional connectivity is shaped by monosynaptic excitatory connections, rather than by collective synchrony. Our method can discriminate between actual causal influences between neurons and spurious non-causal correlations due to light scattering artifacts, which inherently affect the quality of fluorescence imaging. Compared to other reconstruction strategies such as cross-correlation or Granger Causality methods, our method based on improved Transfer Entropy is remarkably more accurate. In particular, it provides a good estimation of the excitatory network clustering coefficient, allowing for discrimination between weakly and strongly clustered topologies. Finally, we demonstrate the applicability of our method to analyses of real recordings of in vitro disinhibited cortical cultures where we suggest that excitatory connections are characterized by an elevated level of clustering compared to a random graph (although not extreme) and can be markedly non-local.

Characterization of hydroxyapatite laser ablation plumes by fast intensified CCD-imaging

ArF excimer laser pulses (193 nm, 20 ns, 150 mJ) have been focused on a hydroxyapatite (HA) target in similar conditions to those normally used for thin film deposition. Fast intensified CCD images of HA laser ablation plumes have been taken in vacuum and under different water vapor pressures ranging from 0.01 mbar to 1 mbar. Images of HA ablation in vacuum have shown a plume freely expanding at a constant velocity of 2.3 106 cm/s. HA ablation under a water vapor pressure of 0.01 mbar has revealed an expansion behavior very similar to that of ablation in vacuum. Images taken under a water vapor pressure of 0.1 mbar have shown the formation of a shock structure in the plume. Finally, HA ablation under a water vapor pressure of 1 mbar has revealed the development of some irregularities in the shape of the plume.

Time-resolved imaging of the laser forward transfer of liquids

Time-resolved imaging is carried out to study the dynamics of the laser-induced forward transfer of an aqueous solution at different laser fluences. The transfer mechanisms are elucidated, and directly correlated with the material deposited at the analyzed irradiation conditions. It is found that there exists a fluence range in which regular and well-defined droplets are deposited. In this case, laser pulse energy absorption results in the formation of a plasma, which expansion originates a cavitation bubble in the liquid. After the further expansion and collapse of the bubble, a long and uniform jet is developed, which advances at a constant velocity until it reaches the receptor substrate. On the other hand, for lower fluences no material is deposited. In this case, although a jet can be also generated, it recoils before reaching the substrate. For higher fluences, splashing is observed on the receptor substrate due to the bursting of the cavitation bubble. Finally, a discussion of the possible mechanisms which lead to such singular dynamics is also provided.

Advances in medical imaging applied to bone metastases

Bone metastases are the result of a primary cancer invasion which spreads into the bone marrow through the lymphogenous or hematogenous pathways. Bone metastases are a common complication of cancer.The primary cancers that most frequently metastasize to bone are breast and prostate cancer (65 - 75 %) amongst many others (thyroid 42 %, lung 36 % or kidney 35 %) (Suva et al., 2011). Although the exact incidence of bone metastases is unknown given its dependence on the type of primary cancer, it is estimated that 350,000 people die of bone metastases annually in the United States.