A new protocol for texture mapping process and 2d representation of rupestrian architecture

The development of the survey techniques for architecture and archaeology requires a general review in the methods used for the representation of numerical data. The possibilities offered by data processing allow to find new paths for studying issues connected to the drawing discipline. The research project aimed at experimenting different approaches for the representation of the rupestrian architecture and the texture mapping process. The nature of the rupestrian architecture does not allow a traditional representation of sections and projections of edges and outlines. The paper presents a method, the Equidistant Multiple Sections (EMS), inspired by cartography and based on the use of isohipses generated from different geometric plane. A specific paragraph is dedicated to the texture mapping process for unstructured surface models. One of the main difficulty in the image projection consists in the recognition of homologous points between image and point cloud, above all in the areas with most deformations. With the aid of the “virtual scan” tool a different procedure was developed for improving the correspondences of the image. The result show a sensible improvement of the entire process above all for the architectural vaults. A detailed study concerned the unfolding of the straight line surfaces; the barrel vault of the analyzed chapel has been unfolded for observing the paintings in the real shapes out of the morphological context

Modeling and control of PEM fuel cells

Aplicat embargament des del moment de la defensa fins al 5 de juliol de 2019.In recent years, the PEM fuel cell technology has been incorporated to the R&D plans of many key companies in the automotive, stationary power and portable electronics sectors. However, despite current developments, the technology is not mature enough to be significantly introduced into the energy market. Performance, durability and cost are the key challenges. The performance and durability of PEM fue! cells significantly depend on variations in the concentrations of hydrogen and oxygen in the gas channels, water activity in the catalyst layers and other backing layers, water content in the polymer electrolyte membrane, as well as temperature, among other variables. Such variables exhibit intemal spatial dependence in the direction of the fuel and air streams of the anode and cathode. Highly non-uniform spatial distributions in PEM fuel cells result in local over-heating, cell flooding, accelerated ageing, and lower power output than expected. Despite the importance of spatial variations of certain variables in PEM fuel cells, not many works available in the literature target the control of spatial profiles. Most control-oriented designs use lumped-parameter models because of their simplicity and convenience for controller performance. In contrast, this Doctoral Thesis targets the distributed parameter modelling and control of PEM fuel cells. In the modelling part, the research addresses the detailed development of a non-linear distributed parameter model of a single PEM fuel cell, which incorporates the effects of spatial variations of variables that are relevant to its proper performance. The model is first used to analyse important cell intemal spatial profiles, and it is later simplified in arder to decrease its computational complexity and make it suitable for control purposes. In this task, two different model order reduction techniques are applied and compared. The purpose of the control part is to tackle water management and supply of reactants, which are two major PEM fuel cell operation challenges with important degradation consequences. In this part of the Thesis, two decentralised control strategies based on distributed parameter model predictive controllers are designed, implemented and analysed via simulation environment State observers are also designed to estímate intemal unmeasurable spatial profiles necessary for the control action. The aim of the first strategy is to monitor and control observed water activity spatial profiles on both sides of the membrana to appropriate levels. These target values are carefully chosen to combine proper membrane, catalyst layer and gas diffusion layer humídification, whilst the rate of accumulation of excess liquid water is reduced. The key objective of this approach is to decrease the frequency of water removal actions that cause disruption in the power supplied by the cell, increased parasitic losses or degradation of cell efficiency. The second strategy is a variation of the previous water activity control strategy, which includes the control of spatial distribution of gases in the fuel and air channels. This integrated solution aims to avoid starvation of reactants by controlling corresponding concentration spatial profiles. This approach is intended to prevent PEM fuel cell degradation due to corrosion mechanisms, and thennal stress caused by the consequences of reactant starvation.A pesar de los avances actuales, la tecnología de celdas de hidrógeno tipo PEM no está suficientemente preparada para ser ampliamente introducida en el mercado energético. Rendimiento, durabilidad y costo son los mayores retos. El rendimiento y la durabilidad de las celdas dependen significativamente de las variaciones en las concentraciones de hidrógeno y oxígeno en los canales de alimentación de gases, la humedad relativa en las capas catalizadoras, el contenido de agua de la membrana polimérica, así como la temperatura, entre otras variables. Dichas variables presentan dependencia espacial interna en la dirección del flujo de gases del ánodo y del cátodo. Distribuciones espaciales altamente no uniformes en algunas variables de la celda resultan en sobrecalentamiento local, inundación, degradación acelerada y menor potencia de la requerida. Muy pocos trabajos disponibles en la literatura se ocupan del control de perfiles espaciales. La mayoría de los diseños orientados a control usan modelos de parámetros concentrados que ignoran la dependencia espacial de variables internas de la celda, debido a la complejidad que añaden al funcionamiento de controladores. En contraste, esta Tesis Doctoral trata la modelización y control de parámetros distribuidos en las celdas de hidrógeno tipo PEM. En la parte de modelización, esta tesis presenta el desarrollo detallado de un modelo no lineal de parámetros distribuidos para una sola celda, el cual incorpora las variaciones espaciales de todas las variables que son relevantes para su correcto funcionamiento. El modelo se usa primero para analizar importantes perfiles espaciales internos, y luego se simplifica para reducir su complejidad computacional y adecuarlo a propósitos de control. En esta tarea se usan y se comparan dos técnicas de reducción de orden de modelos. El propósito de la parte de control es abordar la gestión de agua y el suministro de reactantes, que son dos grandes retos en el funcionamiento de las celdas con importantes consecuencias para su vida útil. En esta parte de la tesis, dos estrategias de control descentralizadas, basadas en controladores predictivos de modelos de referencia con parámetros distribuidos, son diseñadas, implementadas y analizadas en un entorno de simulación. Estas tareas incluyen también el diseño de observadores de estado que estiman los perfiles espaciales internos necesarios para la acción de control. El objetivo de la primera estrategia es monitorear y controlar perfiles espaciales observados de la humedad relativa en las capas catalizadoras para mantenerlos en niveles apropiados. Estos niveles son escogidos cuidadosamente para combinar la correcta humidificación de la membrana y las capas catalizadoras, reduciendo la velocidad de acumulación de agua líquida. El objetivo clave de este enfoque es disminuir la frecuencia de las acciones de remoción de agua dentro de la celda, ya que estas acciones causan interrupción en la potencia suministrada, aumento de las cargas parasitarias y disminución de la eficiencia. La segunda estrategia es una variación de la estrategia anterior que considera adicionalmente el control de la distribución espacial de los gases en los canales del ánodo y cátodo. Esta solución integrada tiene como objetivo evitar la ausencia local de reactantes mediante el control de perfiles espaciales de concentración de gases. Este enfoque pretende prevenir la degradación de las celdas debido a mecanismos de corrosión. Los resultados muestran un mayor rendimiento de la celda considerando los enfoques de control de perfiles espaciales propuestos en esta tesis, en comparación con técnicas de control que ignoran dichos perfiles. Además, la característica descentralizada de los esquemas de control, combinada con el uso de modelos reducidos dentro de los controladores predictivos, tiene un impacto positivo importante en el rendimiento general del control.Postprint (published version

Close range mini Uavs photogrammetry for architecture survey

The survey of historical façades contains several bottlenecks, mainly related to the geometrical structure, the decorative framework, the presence of natural or artificial obstacles, the environment limitations. Urban context presents additional restrictions, binding by ground acquisition activity and leading to building data loss. The integration of TLS and close-range photogrammetry allows to go over such stuff, not overcoming the shadows effect due to the ground point of view. In the last year the massive use of UAVs in survey activity has permitted to enlarge survey capabilities, reaching a deeper knowledge in the architecture analysis. In the meanwhile, several behaviour rules have been introduced in different countries, regulating the UAVs use in different field, strongly restricting their application in urban areas. Recently very small and light platforms have been presented, which can partially overcome these rules restrictions, opening to very interesting future scenarios. This article presents the application of one of these very small RPAS (less than 300 g), equipped with a low-cost camera, in a close range photogrammetric survey of an historical building façade in Bologna (Italy). The suggested analysis tries to point out the system accuracy and details acquisition capacity. The final aim of the paper is to validate the application of this new platform in an architectonic survey pipeline, widening the future application of close-range photogrammetry in the architecture acquisition process

Il Disegno per la ricostruzione di una storia. Il restauro virtuale del Monumento a Costanzo Ciano a Montenero di Livorno

In un eterogeneo contesto storico-culturale, talvolta animato da umano pregiudizio, il porre l’attenzione su uno degli elementi simbolici più rappresentativi del Ventennio, potrebbe configurarsi forse come un atteggiamento provocatorio, ma prescindendo da considerazioni che esulano dagli intenti degli scriventi, il Monumento a Costanzo Ciano, riteniamo rappresenti un tanto interessante quanto emblematico episodio artistico di quel preciso periodo culturale. L’interesse non si limita alla sola valenza delle “tessere”, ancor oggi diffuse sul territorio nazionale, di un mosaico rimasto incompiuto, ma anche nelle ingenti ed interessanti testimonianze documentali di progetto. Elementi la cui lettura interpretativa è stata condotta mediante le metodologie di studio, proprie della Disciplina del Disegno, e più in particolare inerenti il campo del ‘restauro virtuale’, da intendere in questo caso come unico possibile ed efficace strumento di recupero di compiutezza formale, oltre che di comunicazione e divulgazione.The study about the Monument devoted to Costanzo Ciano, one of the most symbolic elements of the fascist period, could be considered provocative in such an historical and cultural period signed by human prejudice, but going beyond the writers’ intentions, the aim of this research is to investigate this interesting and emblematic artistic episode of that cultural period. The interest is not only limited to the value of the lost ‘pieces’ belonged to the unfinished mosaic and still scattered on the national territory, but it’s also related to the great and interesting documentary evidences associated to the project. Methodologies framed in the Representation Discipline have been applied for document interpretation, with attention to the ‘virtual restoration’ as the only possible and effective methodology both to recover its formal completeness, as well as of communicate and divulgate it

The ancient Roman gate along Appian way: San Sebastiano Gate

[EN] The application of integrated survey techniques and 3D modelling methodologies for Cultural Heritage analysis is now considered a consolidated process, while preserving and suggesting continuous research lines related from one side to the evolution of acquisition and restitution instruments, from the other to the problems linked to the specific case study and the goal of the research. This article describes the analysis of one of the largest and best-preserved gates of Rome, located within the Aurelian walls: Porta San Sebastiano. The original name of this gate was Porta Appia, transformed in the Middle Ages into San Sebastiano from the name of the Christian martyr buried in the Basilica on the Via Appia, located just outside the walls. The current gate aspect is the result of many architectural changes over the centuries, as well as a transformation happened in the twentieth century which has led it to a residential use, a unique example of its kind. Through the integration of different survey techniques, a geometric analysis of the complex building is completed, highlighting the construction complexity and the spatial articulation. A parametric model of a portion of the building is then suggested, aimed at understanding the logic underlying the definition of a HBIM model related to an existing complex artefact. Through an integrated analysis, the aim of the article is to provide an advancement in the knowledge of the specific Cultural Heritage through the integration of complementary methods of analysis and representation.Russo, M.; Lanfranchi, F.; Carnevali, L. (2020). The ancient Roman gate along Appian way: San Sebastiano Gate. Editorial Universitat Politècnica de València. 447-454. https://doi.org/10.4995/FORTMED2020.2020.11337OCS44745

Prefazione

La prefazione al libro riguarda la presentazione al volume, una sua valutazione sia complessiva che puntuale dal punto di vista contenutistico, attraverso una analisi qualitativa degli argomenti trattati nel rispetto dei temi propri del Settore Scientifico Disciplinare del Disegno

Performability evaluation of the ERTMS/ETCS - Level 3

Abstract Level 3 of the ERTMS/ETCS improves the capacity of railways by replacing fixed-block signalling, which prevents a train to enter a block occupied by another train, with moving block signalling, which allows a train to proceed as long as it receives radio messages ensuring that the track ahead is clear of other trains. If messages are lost, a train must stop for safety reasons within a given deadline, even though the track ahead is clear, making the availability of the communication link crucial for successful operation. We combine analytic evaluation of failures due to burst noise and connection losses with numerical solution of a non-Markovian model representing also failures due to handovers between radio stations. In so doing, we show that handovers experienced by a pair of chasing trains periodically affect the availability of the radio link, making behavior of the overall communication system recurrent over the hyper-period of periodic message releases and periodic arrivals at cell borders. As a notable aspect, non-Markovian transient analysis within two hyper-periods is sufficient to derive an upper bound on the first-passage time distribution to an emergency brake, permitting to achieve a trade-off between railway throughput and stop probability. A sensitivity analysis is performed with respect to train speed and headway distance, permitting to gain insight into the consequences of system-level design choices

Distributed parameter model simulation tool for PEM fuel cells

En este trabajo se ha desarrollado una herramienta de simulación para pilas de combustible tipo PEM, basada en un modelo de parámetros distribuidos. La herramienta está diseñada para realizar estudios de variaciones espaciales y temporales a lo largo de los canales de alimentación de reactantes. El trabajo muestra y analiza los resultados de simulación de una monocelda monocanal. Las variables estudiadas son las concentraciones de los reactantes, presiones, temperaturas, humidificación, contenido de agua de la membrana, corriente, entre otras que influyen significativamente sobre el rendimiento y durabilidad de las pilas PEM.Peer ReviewedPostprint (published version