1,372 research outputs found

    LIPIcs, Volume 251, ITCS 2023, Complete Volume

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    LIPIcs, Volume 251, ITCS 2023, Complete Volum

    Advances and Applications of DSmT for Information Fusion. Collected Works, Volume 5

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    This fifth volume on Advances and Applications of DSmT for Information Fusion collects theoretical and applied contributions of researchers working in different fields of applications and in mathematics, and is available in open-access. The collected contributions of this volume have either been published or presented after disseminating the fourth volume in 2015 in international conferences, seminars, workshops and journals, or they are new. The contributions of each part of this volume are chronologically ordered. First Part of this book presents some theoretical advances on DSmT, dealing mainly with modified Proportional Conflict Redistribution Rules (PCR) of combination with degree of intersection, coarsening techniques, interval calculus for PCR thanks to set inversion via interval analysis (SIVIA), rough set classifiers, canonical decomposition of dichotomous belief functions, fast PCR fusion, fast inter-criteria analysis with PCR, and improved PCR5 and PCR6 rules preserving the (quasi-)neutrality of (quasi-)vacuous belief assignment in the fusion of sources of evidence with their Matlab codes. Because more applications of DSmT have emerged in the past years since the apparition of the fourth book of DSmT in 2015, the second part of this volume is about selected applications of DSmT mainly in building change detection, object recognition, quality of data association in tracking, perception in robotics, risk assessment for torrent protection and multi-criteria decision-making, multi-modal image fusion, coarsening techniques, recommender system, levee characterization and assessment, human heading perception, trust assessment, robotics, biometrics, failure detection, GPS systems, inter-criteria analysis, group decision, human activity recognition, storm prediction, data association for autonomous vehicles, identification of maritime vessels, fusion of support vector machines (SVM), Silx-Furtif RUST code library for information fusion including PCR rules, and network for ship classification. Finally, the third part presents interesting contributions related to belief functions in general published or presented along the years since 2015. These contributions are related with decision-making under uncertainty, belief approximations, probability transformations, new distances between belief functions, non-classical multi-criteria decision-making problems with belief functions, generalization of Bayes theorem, image processing, data association, entropy and cross-entropy measures, fuzzy evidence numbers, negator of belief mass, human activity recognition, information fusion for breast cancer therapy, imbalanced data classification, and hybrid techniques mixing deep learning with belief functions as well

    Machine Learning Approaches for Semantic Segmentation on Partly-Annotated Medical Images

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    Semantic segmentation of medical images plays a crucial role in assisting medical practitioners in providing accurate and swift diagnoses; nevertheless, deep neural networks require extensive labelled data to learn and generalise appropriately. This is a major issue in medical imagery because most of the datasets are not fully annotated. Training models with partly-annotated datasets generate plenty of predictions that belong to correct unannotated areas that are categorised as false positives; as a result, standard segmentation metrics and objective functions do not work correctly, affecting the overall performance of the models. In this thesis, the semantic segmentation of partly-annotated medical datasets is extensively and thoroughly studied. The general objective is to improve the segmentation results of medical images via innovative supervised and semi-supervised approaches. The main contributions of this work are the following. Firstly, a new metric, specifically designed for this kind of dataset, can provide a reliable score to partly-annotated datasets with positive expert feedback in their generated predictions by exploiting all the confusion matrix values except the false positives. Secondly, an innovative approach to generating better pseudo-labels when applying co-training with the disagreement selection strategy. This method expands the pixels in disagreement utilising the combined predictions as a guide. Thirdly, original attention mechanisms based on disagreement are designed for two cases: intra-model and inter-model. These attention modules leverage the disagreement between layers (from the same or different model instances) to enhance the overall learning process and generalisation of the models. Lastly, innovative deep supervision methods improve the segmentation results by training neural networks one subnetwork at a time following the order of the supervision branches. The methods are thoroughly evaluated on several histopathological datasets showing significant improvements

    Design and characterisation of monolithic CMOS detectors for high energy particle physics and SEU radiation tests for ATLAS Inner Tracker Upgrade readout chip

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    This thesis covers the characterisation results and the design of monolithic CMOS detectors designed in TowerJazz 180nm CMOS technology for High Energy Particle Physics applications. Three different detectors have been studied the MALTA, the Mini-MALTA and the MALTA2. The MALTA sensor showed some efficiency losses at the corners of the pixels after irradiation, which meant that it was not suitable for the radiation environments in which it was supposed to be installed. Therefore, the front-end electronics and the fabrication process were modified to overcome this issue. The Mini-MALTA prototype was designed including the above mentioned improvements, fabricated and fully characterised. Finally taking into account all the knowledge acquired during these years of developments another large scale sensor the MALTA2 has been produced which should be radiation tolerant and have very good time resolution. The description and studies of the different architectures used in this family of detectors are covered and a simulation to estimate the bandwidth capabilities have been reported. Furthermore, this work will present characterisation of single event effects in the ITkPixV1, the prototype version of the ATLAS Inner Tracker Upgrade chip for the High Luminosity LHC. Measurements were made in testbeam campaigns with high energy ions and protons to evaluate the level of single event effects in the chip

    Planar Disjoint Paths, Treewidth, and Kernels

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    In the Planar Disjoint Paths problem, one is given an undirected planar graph with a set of kk vertex pairs (si,ti)(s_i,t_i) and the task is to find kk pairwise vertex-disjoint paths such that the ii-th path connects sis_i to tit_i. We study the problem through the lens of kernelization, aiming at efficiently reducing the input size in terms of a parameter. We show that Planar Disjoint Paths does not admit a polynomial kernel when parameterized by kk unless coNP \subseteq NP/poly, resolving an open problem by [Bodlaender, Thomass{\'e}, Yeo, ESA'09]. Moreover, we rule out the existence of a polynomial Turing kernel unless the WK-hierarchy collapses. Our reduction carries over to the setting of edge-disjoint paths, where the kernelization status remained open even in general graphs. On the positive side, we present a polynomial kernel for Planar Disjoint Paths parameterized by k+twk + tw, where twtw denotes the treewidth of the input graph. As a consequence of both our results, we rule out the possibility of a polynomial-time (Turing) treewidth reduction to tw=kO(1)tw= k^{O(1)} under the same assumptions. To the best of our knowledge, this is the first hardness result of this kind. Finally, combining our kernel with the known techniques [Adler, Kolliopoulos, Krause, Lokshtanov, Saurabh, Thilikos, JCTB'17; Schrijver, SICOMP'94] yields an alternative (and arguably simpler) proof that Planar Disjoint Paths can be solved in time 2O(k2)nO(1)2^{O(k^2)}\cdot n^{O(1)}, matching the result of [Lokshtanov, Misra, Pilipczuk, Saurabh, Zehavi, STOC'20].Comment: To appear at FOCS'23, 82 pages, 30 figure

    Design and Development of a Multi-Frequency System for Microwave Heating

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    [ES] La utilización de sistemas de microondas para aplicaciones de calentamiento está muy extendida, principalmente por su uso en el calentamiento doméstico. El volumen de ventas del horno de microondas doméstico refleja un dato curioso: es el electrodoméstico más vendido en el mundo cada año. Por ello, el coste de producción del elemento principal, el magnetrón, presenta unos márgenes de beneficio imbatibles. Sin embargo, los avances en la fabricación de generadores de RF de alta potencia de estado sólido han puesto de manifiesto no solo las limitaciones de los sistemas basados en magnetrón sino también las grandes ventajas de la tecnología de transistores. Actualmente, los amplificadores de potencia de estado sólido han alcanzado una madurez suficiente como para competir en eficiencia, coste y calidad de la onda generada con el magnetrón. Las principales ventajas de los transistores son un reducido tamaño, tensiones de alimentación bajas, un espectro puro en frecuencia, un mayor tiempo de vida y el control digital directo. Los sistemas de microondas con esta tecnología están siendo introducidos en el mercado desde hace diez años, aunque las aplicaciones reales que los utilizan son escasas. La principal razón es la falta de diseños de aplicadores específicos para sacar el máximo provecho a las fuentes de estado sólido. , por tanto, es éste el objetivo de la tesis doctoral. Los sistemas S2MH (Solid-State Microwave Heating) se presentan en esta disertación doctoral como una alternativa que ofrece un calentamiento mejorado. La posibilidad de seleccionar la frecuencia exacta, ajustar la potencia de salida y realizar barridos de fase de forma coherente con múltiples iluminadores proporcionan al sistema un control preciso del proceso de calentamiento. El resultado directo de éste es un calentamiento homogéneo y el uso de la tecnología de microondas en procesos de alto valor añadido y fuerte dependencia con la temperatura. Esta tesis doctoral presenta el trabajo realizado en el diseño y fabricación de dos sistemas S2MH: el primero es un horno estático versátil para diferentes procesos químicos, y el segundo un horno de transporte para el secado de almendras. Estos dos sistemas están formados por el SSMGS (Solid-State Microwave Generator System), que incluye cuatro amplificadores de estado sólido (SSPA) con una generación de la onda coherente, y el aplicador. Para el diseño del SSMGS se han tenido en cuenta los requisitos de potencia y frecuencia de cada aplicación. Se ha utilizado un SSMGS con cuatro PA de 250 W a 2,450 MHz para el horno de aplicaciones químicas, mientras que el secado de almendras necesita cuatro PA de 500 W a 915 MHz. Los dos sistemas de generación de microondas permiten un control individual o combinado de los parámetros de los cuatro módulos amplificadores, i.e., potencia, frecuencia y fase. Todo el proceso de diseño ha sido llevado a cabo mediante modelado multi-físico, poniendo un especial cuidado en las propiedades termofísicas y dieléctricas de los alimentos y soluciones acuosas que tienen una importante dependencia con la temperatura. El comportamiento completo del sistema aplicador se ha estudiado con estas herramientas. Tras la fabricación de los dos prototipos o pruebas de concepto (PoC), los resultados obtenidos presentan un comportamiento similar al modelo y muestran, además, prometedoras mejoras frente a los sistemas actuales. El sistema de aplicaciones químicas presenta mejoras en la distribución de campo, independientemente de la aplicación y la carga. Y el sistema de secado de almendras proporciona un mayor control sobre el proceso evitando la pérdida de material por sobrecalentamiento.[CA] La utilització de sistemes de microones en aplicacions d'escalfament està molt estesa, principalment pel seu us en escalfament domèstic. El volum de ventes del forn de microones domèstic reflexa una informació curiosa: es l'electrodomèstic més venut anualment al món. Per això, el cost de producció del seu element principal, el magnetró, presenta uns marges de benefici imbatibles. No obstant això, els avanços en la fabricació de generadors de RF d'alta potencia d'estat sòlid han posat de manifest tant les limitacions dels sistemes basats en magnetró, com els grans avantatges de la tecnologia de transistors. Actualment, els amplificadors de potència d'estat sòlid son el suficientment madurs com per competir en eficiència, cost i qualitat de l'ona generada amb el magnetró. Els principals avantatges dels transistors son les dimensions reduïdes, tensions d'alimentació baixes, un espectre pur en freqüència, major temps de vida i el control digital directe. Els sistemes de microones amb aquesta tecnologia estan sent introduïts al mercat des de fa deu anys, malgrat les aplicacions reals son escasses. El principal motiu és la falta de dissenys de aplicadors específics per obtindré el màxim profit de les fonts d'estat sòlid. , por tanto, es éste el objetivo de la tesis doctoral. Els sistemes S2MH es presenten en esta dissertació doctoral com una alternativa que ofereix un escalfament millorat. La possibilitat de seleccionar la freqüència exacta, ajustar la potència d'eixida i realitzar un rastreig de fase de forma coherent amb molts il·luminadors proporcionen al sistema un control precís del procés d'escalfament. El resultat directe d'aquest es un escalfament homogeni i el us de la tecnologia de microones en processos d'alt valor afegit i alta sensibilitat a la temperatura. Aquesta dissertació doctoral presenta el treball realitzat en el disseny i fabricació de dos sistemes S2MH: el primer és un forn estàtic i versàtil per a diferent processos químics, i el segon es tracta d'un forn de transport per l'assecatge d'ametles. Tots dos sistemes estan formats pel SSMGS, que inclou quatre amplificadors d'estat sòlid (SSPA) amb generació coherent de l'ona, i l'aplicador. Per al disseny del SSMGS s'han tingut en compte els requisits de potència i freqüència de cada aplicació. S'ha utilitzat un SSMGS amb quatre PA de 250 W a 2,450 MHz per al forn d'aplicacions químiques, mentre que per al d'assecat d'ametla es necessita quatre PA de 500 W a 915 MHz. Ambdós sistemes de generació de microones permeten un control individual o combinat dels paràmetres dels quatre mòduls amplificadors, i.e., potència, freqüència i fase. Tot el procés de disseny ha sigut realitzat amb l'ajuda del modelat multi-físic, prestant una especial atenció a les propietats termofísiques i dielèctriques dels aliments i solucions aquoses, que tenen una important dependència de la temperatura. El comportament complet del sistema aplicador ha sigut estudiat amb estes ferramentes digitals. Després de la fabricació dels dos prototips o proves de concepte (PoC), els resultats obtinguts presenten un comportament similar al model i, a més a més, mostren millores prometedores front als sistemes actuals. El sistema d'aplicacions químiques presenta millores en la distribució de camp, independentment de l'aplicació i la càrrega. I el sistema d'assecatge d'ametlles proporciona un major control sobre el procés, evitant la pèrdua de material per sobreescalfament.[EN] Microwave systems are widely used for heating applications, mainly domestic food heating. The microwave oven sales figures place it as the first domestic appliance, giving its core element, the magnetron, an unbeatable production cost margin. However, recent improvements in RF high-power generator manufacturing have pointed out not only the limitations of these systems based on the magnetron but also the main benefits of the transistors technology. Nowadays, solid-state power amplifiers are mature enough to compete in efficiency, cost and quality with the magnetron. Transistors' main benefits are their reduced size, low operation voltages, pure frequency spectrum, lifetime, and straightforward digital control. Microwave systems based on solid-state power amplifiers have been recently introduced, although the real applications making use of them are rare. The main issue is the lack of applicator designs for specific solid-state sources that fully exploit the mentioned advantages; therefore, this is the main objective of the present PhD thesis. Solid-State Microwave Heating (S2MH) systems are presented in this PhD dissertation as an alternative that offers enhanced heating. Fine frequency selection, adjustable output power and coherent phase sweep in multiple outputs provide the system with accurate control over the heating process. The direct outcome of this control is the production of homogeneous heating and the application of microwave technology into high-added-value temperature-sensitive processes. The complete design and manufacture of two S2MH systems have been carried out and presented in this PhD thesis. The two designed systems are a multi-process chemical lab batch oven and an almond drying conveyorized oven. These two systems are composed of the Solid-State Microwave Generator System (SSMGS), consisting of four Solid-State Power Amplifiers (SSPA) with coherent wave generation, and the applicator. The design of the SSMGS has been carried out according to the power and frequency requirements of the application. A 4 x 250 W SSPA at 2,450 MHz SSMGS has been used for the chemical processes oven, while the almond drying application needs 4 x 500 W SSPA at 915 MHz. Both SSMGS allow the individual or combined digital control of the parameters of the four amplifying modules, i.e., power, frequency and phase. Multiphysics modelling has been thoroughly studied with special attention to the temperature-dependent thermophysical and dielectric properties of food and liquid solutions. The overall applicators' behaviour has been analysed with this tool. After completing the two PoC (Proof of Concept), the results show good agreement with the models. Both PoCs have shown promising improvements to the current state-of-the-art systems. The chemical applications PoC shows electromagnetic field distribution improvements, independent of the application or load. On the other hand, the almonds drying system provides increased control over the process avoiding material losses through overheating.Santón Pons, P. (2022). Design and Development of a Multi-Frequency System for Microwave Heating [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/19132

    LIPIcs, Volume 261, ICALP 2023, Complete Volume

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    LIPIcs, Volume 261, ICALP 2023, Complete Volum

    Integrality and cutting planes in semidefinite programming approaches for combinatorial optimization

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    Many real-life decision problems are discrete in nature. To solve such problems as mathematical optimization problems, integrality constraints are commonly incorporated in the model to reflect the choice of finitely many alternatives. At the same time, it is known that semidefinite programming is very suitable for obtaining strong relaxations of combinatorial optimization problems. In this dissertation, we study the interplay between semidefinite programming and integrality, where a special focus is put on the use of cutting-plane methods. Although the notions of integrality and cutting planes are well-studied in linear programming, integer semidefinite programs (ISDPs) are considered only recently. We show that manycombinatorial optimization problems can be modeled as ISDPs. Several theoretical concepts, such as the Chvátal-Gomory closure, total dual integrality and integer Lagrangian duality, are studied for the case of integer semidefinite programming. On the practical side, we introduce an improved branch-and-cut approach for ISDPs and a cutting-plane augmented Lagrangian method for solving semidefinite programs with a large number of cutting planes. Throughout the thesis, we apply our results to a wide range of combinatorial optimization problems, among which the quadratic cycle cover problem, the quadratic traveling salesman problem and the graph partition problem. Our approaches lead to novel, strong and efficient solution strategies for these problems, with the potential to be extended to other problem classes
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