Analyse et optimisation de problèmes sous contraintes d'autocorrélation

fin de rédaction : 20-07-2007In this work, we study how to take into account, from the convex analysis and optimization viewpoint, constraint sets of the following type : sets of vectors whose components are autocorrelations lags of finite discrete signals. A set of vectors with autocorrelated components turns out to be a convex cone, for which we etablish many basic properties such as : smoothness or not of the boundary, structure of faces, acuteness, expression of the polar cone, evaluation of the normal cone at a point, etc. Next, we propose some algorithms to solve optimization problems where this type of constraint set appears ; in particular we consider the problem of projecting a point on the convex cone of vectors with autocorrelated constraints. For these purposes, we study three different algorithms : an interior point method, one using alternating projections, and one via a non-convex relaxation of the original problem. Finally, we suggest extensions to the bi-dimensional signals case ; we outline the main difficulties which therefore appear : various possible new definitions, non-convexity of occuring problems, and increase in the computational complexity of the algorithmic procedures.Dans ce travail de thèse, nous étudions, dans un contexte d'analyse convexe et d'optimisation, la prise en compte des contraintes dites d'autocorrélation, c'est-à-dire : nous considérons les situations où les vecteurs représentant les variables à optimiser sont contraintes à être les coefficients d'autocorrélation d'un signal discret à support fini. Cet ensemble des vecteurs à composantes autocorrélées se trouve être un cône convexe ; nous essayons d'en établir le plus de propriétés possibles : concernant sa frontière (lisse/polyédrale), ses faces, l'acuité, l'expression du cône polaire, l'évaluation du cône normal en un point, etc. Ensuite, nous étudions divers algorithmes pour résoudre des problèmes d'optimisation où le cône des vecteurs à composantes autocorrélées entre en jeu. Notre principal objet d'étude est le problème de la projection sur ce cône, dont nous proposons la résolution par trois algorithmes différents : algorithmes dits de suivi de chemin, celui des projections alternées, et via une relaxation non-convexe. Enfin, nous abordons la généralisation de la situation d'autocorrélation au cas de signaux bi-dimensionnels, avec toute la complexité que cela engendre : multiples définitions possibles, non-convexité des problèmes résultants, et complexité calculatoire accrue pour les algorithmes

Grado de competencia digital y usos TIC en profesoras del Campo de Gibraltar

Esta investigación sirve para conocer y estudiar el grado de competencia digital y uso de redes sociales, la calidad relacional online y la inmersión digital de las profesoras correspondientes a la zona de Gibraltar de la que es responsable el CEP de Algeciras-La Línea. La metodología es cuantitativa, de corte correlacional y descriptivo, con una muestra de 1134 profesoras. El instrumento de investigación es un cuestionario que contiene diversos bloques con los constructos vinculados a la investigación diagnóstica de la competencia digital de estas profesoras. Por último, hemos podido saber que el grado de uso con las redes sociales es a diario, siendo la aplicación WhatsApp la más utilizada. En cuanto a dicho uso tecnológico es más difícil en la etapa de infantil que en etapas posteriores. Además se ha podido observar que existe mayor grado de relación entre Calidad Relacional e Inmersión Digital y entre Calidad Relacional y Competencia Digital. Al predecir la calidad relacional online dentro las competencias digitales generales especificamos dos especialmente importantes (Competencia digital socio comunicativa y Competencia digital emocional).The aim of this research is to know and study the digital skill level and network use, online relational quality and digital inmersion from female teachers of CEP1 de Algeciras-La Línea (Gibraltar). The metodology is cuantitative, correlational and descriptive, with a population of 1134 female teachers. The research instrument consist in a survey with several measure with constructs conected to the diagnostic research of these female teachers digital skill. In conclusion, we have discovered that networks are used daily and that WhatsApp is the most used.. However, the use of this App is less common in childhood than in later stages. Futhermore, it has been noticed that the connecting level is higher between relational quality and digital inmersion and between relational quality and digital skill. After predicting online relational quality inside general digital skills, we specify two important digital skills (comunicational digital skill and emotional digital skill).Universidad de Sevilla. Grado en Pedagogí

Disseny d'una bicicleta de neu

Aquest projecte pretén explicar el procés desenvolupat per al disseny d'una bicicleta de neu. El vehicle, a grans trets, és una bicicleta tot terreny adaptada per a la pràctica de l'esquí. El lector podrà trobar, a continuació, el camí a seguir des de la gènesi d'un nou concepte de vehicle fins a trobar un disseny validat d'un prototip llest per ser fabricat i provat en condicions reals. Abans de sintetitzar la bicicleta, s'analitza el context i els antecedents del vehicle. Amb aquest bagatge, es defineix l'ús específic que se li vol donar a aquesta bicicleta per tal de fer un disseny adequat. La fase disseny comença explicant una geometria preparada per satisfer l'ús que prèviament s'ha definit. A continuació, es vesteix la geometria amb el disseny d'un primer prototip modelant la solució adoptada. Posteriorment, en la part de càlcul, es valida el disseny proposat. Per això, es comproven els elements estructurals principals i les unions escollides durant la fase de disseny. El resultat és una bicicleta de neu preparada per ser fabricada com a prototip i per ser posada a prova en condicions reals

Modelització d'un aerogenerador offshore

Aquest projecte consisteix en el disseny i modelització d’un aerogenerador offshore (al mar). Aquest treball pretén aprofundir en l’anàlisi i el control de l’energia eòlica, en aquest cas generada al mar. L’estructura del treball consta de diferents blocs: en el primer es descriuen les parts i el funcionament d’un aerogenerador, i més tard es dissenya un model i un sistema de control, amb el qual es faran simulacions i s’estudiaran els resultat

Integration of a Retrograde Signal during Synapse Formation by Glia-Secreted TGF-β Ligand

SummaryGlial cells are crucial regulators of synapse formation, elimination, and plasticity [1, 2]. In vitro studies have begun to identify glial-derived synaptogenic factors [1], but neuron-glia signaling events during synapse formation in vivo remain poorly defined. The coordinated development of pre- and postsynaptic compartments at the Drosophila neuromuscular junction (NMJ) depends on a muscle-secreted retrograde signal, the TGF-β/BMP Glass bottom boat (Gbb) [3, 4]. Muscle-derived Gbb activates the TGF-β receptors Wishful thinking (Wit) and either Saxophone (Sax) or Thick veins (Tkv) in motor neurons [3, 4]. This induces phosphorylation of Mad (P-Mad) in motor neurons, its translocation into the nucleus with a co-Smad, and activation of transcriptional programs controlling presynaptic bouton growth [5]. Here we show that NMJ glia release the TGF-β ligand Maverick (Mav), which likely activates the muscle activin-type receptor Punt to potently modulate Gbb-dependent retrograde signaling and synaptic growth. Loss of glial Mav results in strikingly reduced P-Mad at NMJs, decreased Gbb transcription in muscle, and in turn reduced muscle-to-motor neuron retrograde TGF-β/BMP signaling. We propose that by controlling Gbb release from muscle, glial cells fine tune the ability of motor neurons to extend new synaptic boutons in correlation to muscle growth. Our work identifies a novel glia-derived synaptogenic factor by which glia modulate synapse formation in vivo

Multi-modal Deep Learning Approach for Flood Detection

In this paper we propose a multi-modal deep learning approach to detect floods in social media posts. Social media posts normally contain some metadata and/or visual information, therefore in order to detect the floods we use this information. The model is based on a Convolutional Neural Network which extracts the visual features and a bidirectional Long Short-Term Memory network to extract the semantic features from the textual metadata. We validate the method on images extracted from Flickr which contain both visual information and metadata and compare the results when using both, visual information only or metadata only. This work has been done in the context of the MediaEval Multimedia Satellite Task

Glia and Muscle Sculpt Neuromuscular Arbors by Engulfing Destabilized Synaptic Boutons and Shed Presynaptic Debris

As synapses grow at the Drosophila neuromuscular junction, they shed membrane material in an activity-dependent manner. Glia and postsynaptic muscle cells are required to engulf this debris to ensure new synaptic growth

Therapy of established B16-F10 melanoma tumors by a single vaccination of CTL/T helper peptides in VacciMax(®)

BACKGROUND: Melanoma tumors are known to express antigens that usually induce weak immune responses of short duration. Expression of both tumor-associated antigens p53 and TRP2 by melanoma cells raises the possibility of simultaneously targeting more than one antigen in a therapeutic vaccine. In this report, we show that VacciMax(® )(VM), a novel liposome-based vaccine delivery platform, can increase the immunogenicity of melanoma associated antigens, resulting in tumor elimination. METHODS: C57BL/6 mice bearing B16-F10 melanoma tumors were vaccinated subcutaneously 6 days post tumor implantation with a mixture of synthetic peptides (modified p53: 232–240, TRP-2: 181–188 and PADRE) and CpG. Tumor growth was monitored and antigen-specific splenocyte responses were assayed by ELISPOT. RESULTS: Vaccine formulated in VM increased the number of both TRP2- and p53-specific IFN-γ producing splenocytes following a single vaccination. Vaccine formulated without VM resulted only in enhanced IFN-γ producing splenocytes to one CTL epitopes (TRP2:180–188), suggesting that VM overcomes antigen dominance and enhances immunogenicity of multiple epitopes. Vaccination of mice bearing 6-day old B16-F10 tumors with both TRP2 and p53-peptides formulated in VM successfully eradicated tumors in all mice. A control vaccine which contained all ingredients except liposomes resulted in eradication of tumors in no more than 20% of mice. CONCLUSION: A single administration of VM is capable of inducing an effective CTL response to multiple tumor-associated antigens. The responses generated were able to reject 6-day old B16-F10 tumors

REVISITING ANNA MOSCOWITZ\u27S KROSS\u27S CRITIQUE OF NEW YORK CITY\u27S WOMEN\u27S COURT: THE CONTINUED PROBLEM OF SOLVING THE PROBLEM OF PROSTITUTION WITH SPECIALIZED CRIMINAL COURTS

This article explores New York City\u27s non-traditional, judicially based response to prostitution. This article first recounts the history of New York City’s Women’s Court. It then examines the work of the Midtown Community Court, the “problem-solving court” established in 1993 to address criminal issues, like prostitution, in Midtown Manhattan. It also discusses the renewed concerns about sex work in New York and describe the movement, propelled by modern reformers, to address prostitution through specialty courts. It then contrasts the shared features and attributes of the Women’s Court and Midtown Court models. Finally, the article urges modern reformers to step back from the problem-solving court movement and their call for the creation of more such specialized criminal courts

Rejection of large HPV-16 expressing tumors in aged mice by a single immunization of VacciMax® encapsulated CTL/T helper peptides

The incidence of cancer increases significantly in later life, yet few pre-clinical studies of cancer immunotherapy use mice of advanced age. A novel vaccine delivery platform (VacciMax®,VM) is described that encapsulates antigens and adjuvants in multilamellar liposomes in a water-in-oil emulsion. The therapeutic potential of VM-based vaccines administered as a single dose was tested in HLA-A2 transgenic mice of advanced age (48–58 weeks old) bearing large palpable TC1/A2 tumors. The VM-based vaccines contained one or more peptides having human CTL epitopes derived from HPV 16 E6 and E7. VM formulations contained a single peptide, a mixture of four peptides or the same four peptides linked together in a single long peptide. All VM formulations contained PADRE and CpG as adjuvants and ISA51 as the hydrophobic component of the water-in-oil emulsion. VM-formulated vaccines containing the four peptides as a mixture or linked together in one long peptide eradicated 19-day old established tumors within 21 days of immunization. Peptide-specific cytotoxic cellular responses were confirmed by ELISPOT and intracellular staining for IFN-γ producing CD8+ T cells. Mice rendered tumor-free by vaccination were re-challenged in the opposite flank with 10 million HLF-16 tumor cells, another HLA-A2/E6/E7 expressing tumor cell line. None of these mice developed tumors following the re-challenge. In summary, this report describes a VM-formulated therapeutic vaccine with the following unprecedented outcome: a) eradication of large tumors (> 700 mm3) b) in mice of advanced age c) in less than three weeks post-immunization d) following a single vaccination