The thesis is divided in two parts, corresponding to the two main subjects on which I have worked during my PhD. In the first Part, we introduce many-body long-range interacting systems, such as plasma and self-gravitating systems. We first review the well known properties of isolated systems, which show peculiar behaviors both for what concern the equilibrium and the relaxation to equilibrium. We then consider long-range systems driven away from equilibrium and we show how the techniques developed for isolated systems can be extended to describe these situations. Generalizations to describe simplified models relevant for geophysical flows and two-dimensional turbulence are also discussed. Our work stands at the edge between the study of long-range interacting systems and the study of non-equilibrium systems.The second part of the thesis is devoted to the study of equilibrium properties of Hamiltonian systems with energy landscape techniques. A number of recent results is reviewed and applied to long and short-range interacting systems. One of the scope of my work was to study models whose energy landscape is much more complicated than what previously done. In the case of ferromagnetic short-range O(n) models on hypercubic lattices, our analysis unveiled a striking similarity between the critical energies of the Ising model and the O(n) models defined on the same lattice with the same interaction matrix. Generalizations of the Stillinger and Weber formalism are discussed as preliminary results and future perspectives.

Thesis (Ph.D.)-University of KwaZulu-Natal, Durban, 2012.

We consider the class of two-player symmetric n x n games with the total bandwagon property (TBP) introduced by Kandori and Rob (1998). We show that a game has TBP if and only if the game has 2^n - 1 symmetric Nash equilibria. We extend this result to bimatrix games by introducing the generalized TBP. This sheds light on the (wrong) conjecture of Quint and Shubik (1997) that any n x n bimatrix game has at most 2^n - 1 Nash equilibria. As for an equilibrium selection criterion, I show the existence of a ½-dominant equilibrium for two subclasses of games with TBP: (i) supermodular games; (ii) potential games. As an application, we consider the minimum-effort game, which does not satisfy TBP, but is a limit case of TBP. (author's abstract) / Series: Department of Economics Working Paper Series

Akademisk avhandling--København. / Dansk resumé. Bibliography: p. [205]-228.

Akademisk avhandling--København. / Dansk resumé. Bibliography: p. [205]-228.

Orientador: Reginaldo Guirardello / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-19T12:38:06Z (GMT). No. of bitstreams: 1 Cunico_LarissaPeixoto_M.pdf: 3845396 bytes, checksum: d8e7fc1418bed93fc9777451bc5ab2e5 (MD5) Previous issue date: 2012 / Resumo: A demanda mundial por energia cresce a cada ano. Essa demanda pode atingir níveis que os recursos atuais de combustíveis fósseis não podem sustentar. Neste contexto, os biocombustíveis surgem como uma fonte crescente de energia primária, aumentando a oportunidade de pesquisa e desenvolvimento de tecnologia a níveis animadores. Uma importante questão relacionada com o desenvolvimento destes biocombustíveis é o equilíbrio de fases entre seus componentes. Este trabalho investiga o equilíbrio líquido-vapor (ELV) de sistemas binários e o equilíbrio líquido-líquido (ELL) de sistemas ternários e quaternários, além do equilíbrio líquido-líquido-vapor (ELLV) de sistemas ternários, compostos por óleo vegetal, álcool, glicerina e éster, envolvidos na produção do biodiesel. O modelo desenvolvido também é capaz de predizer o equilíbrio químico e de fases para vários tipos de óleos vegetais na produção de biodiesel. Para tanto houve a necessidade da estimativa das propriedades físicas destes vários componentes e uma busca por métodos de predição através de contribuição de grupos foi realizada para as propriedades físicas não encontradas na literatura. A minimização da energia de Gibbs foi utilizada para calcular cada fase presente em uma determinada condição de pressão e temperatura, assim como a composição de cada fase prevista. A equação de estado de Soave-Redlich-Kwong (SRK-EOS) com a regra de mistura de van der Waals de dois parâmetros ajustáveis (VdW-2) foi empregada. O software GAMS® 23.1.3 (General Algebraic System Model) combinado com o solver CPLEX foi utilizado para resolver numericamente o modelo matemático. Através de discretização das frações molares, a modelagem do problema pode ser desenvolvida na forma de uma programação linear. Os dados experimentais foram representados de forma satisfatória por estes modelos e utilizando SRK-EOS obteve-se desvio absoluto médio e tempo computacional para sistemas binários, ternários e quaternários respectivamente de 1,03%, 1,39% e 1,30% e 0,17s, 27s e 6s, para os sistemas utilizando metanol. Já para os sistemas que utilizam etanol, o desvio absoluto médio e tempo computacional para sistemas binários e ternários são respectivamente de 0,64% e 2,10% e 0,14s e 26s / Abstract: The worldwide energy demand increases every year. This demand will reach levels that cannot be supplied by current conventional fossil fuel resources. In this context, biofuels arise as a growing primary source of energy, raising research opportunities and encouraging technology development. An important technical issue related to biofuels development is the phase equilibrium among their components. This work investigates the vapor-liquid equilibrium (VLE) and liquid-liquid equilibrium (LLE) of binary, ternary and quaternary systems composed by vegetable oil, alcohol, glycerol and ester, involved in biodiesel production. The Gibbs energy minimization was used to calculate the amount of each phase present in a particular condition of pressure and temperature, as well as the composition of each phase predicted. The Soave-Redlich-Kwong (SRK) equation of state with van der Waals mixing rule, with two adjustable parameters (vdW-2) was employed. The GAMS® 23.2.1 (General Algebraic Model System) in combination with the solver CPLEX was used to tackle the large and complex mathematical models. The minimization of the Gibbs energy was done using a discretized procedure, so that the problem could be solved as a linear programming approach. The proposed model is also used to predict the chemical and phase equilibrium for eight types of vegetable oils in biodiesel production. For this purpose it was necessary to estimate the physical properties of these various components and a search for methods of prediction by group contribution was made to physical properties not found in the literature. The experimental data were correlated quite well by the Soave-Redlich-Kwong (SRK) equation of state, with absolute medium deviations and computational time for binary, ternary and quaternary systems using methanol as a compound of: 0.83% and 0.17s, 1.39% and 27s and 1.30% and 6s, respectively. Using ethanol as a compound, the absolute medium deviations and computational time for binary and ternary systems of: 0,64%, 2,10% , 0,14s and 26s / Mestrado / Desenvolvimento de Processos Químicos / Mestre em Engenharia Química

Submitted in fulfillment of the academic requirements for the degree of Master in Engineering, Durban University of Technology, Durban, South Africa, 2017. / Phase equilibrium data plays a significant role in the design and optimization of industrial separation schemes, such as distillation and absorption units. These separation processes are utilised for the purification of valuable chemicals, which play a pivotal role in daily human life. Separation units are operated at various conditions of temperature and pressure, however it is common for most units to operate in the moderate pressure region (100-500 kPa). On the contrary, there is a lack of phase equilibrium data available in the moderate pressure region, thus prompting an interest in this area. In this study, a new static synthetic cell was tested, and the experimental apparatus was successfully set up and commissioned. Some key features of this design include a total working cell volume of 60 cm3 (which reduces the amount of chemicals required compared to conventional static synthetic cells) and equilibrium is achieved faster. In addition, two high-accuracy Teledyne Isco pumps were utilised for the feed loading, as it is vital that the volume of chemicals dispensed into the cell be accurately determined. The necessary calibrations were conducted and the overall uncertainties were found to be 0.06 K, 0.36 kPa and 0.1 ml for temperature, pressure and volume respectively. The following test systems were measured to determine the reproducibility of the apparatus and to verify the experimental technique: • water (1) + 2-butanol (2) at 323.16 K • n-hexane (1) + 2-butanol (2) at 329.21 K • n-pentane (1) + 1-propanol (2) at 317.18 K • n-pentane (1) + 2-butanol (2) at 303.17 K • n-pentane (1) + ethanol (2) at 303.11 K The test systems measured produced a good fit with the literature data, and thus the experimental apparatus was commissioned. New systems, previously unmeasured in the open literature, were measured in this study. These systems include: • n-hexane (1) + perfluoro-n-heptane (2) at 313.21 and 333.12 K • n-pentane (1) + 2-propanol (2) at 313.11, 323.11 and 333.12 K The data was modelled on Aspen Plus®. Since the method of operation is of the static synthetic type, no analysis of the vapour and liquid phases took place, and instead an algorithm was developed using the combined method (γ-ϕ) together with the method of Barker (1953), to convert the overall composition (zi) to liquid mole fraction (xi). The Wilson and Non-Random Two-Liquid (NRTL) activity coefficient models together with the Ideal Gas law and Hayden O’Connell second virial coefficient were utilised to regress the data. For both the fluorinated and alkane + alcohol systems, the experimental i data produced an excellent fit with the activity coefficient models. For both systems, azeotropes were observed, indicating poor separation of these binary combinations at specific mole fractions. This is due to the boiling point of both components being similar under certain conditions. The calculated pressure residuals were well within the overall combined uncertainty for pressure, whilst the calculated temperature residuals were slightly above the overall combined uncertainty for temperature. / M

The fuel industry in many parts of the world is blending alcohols with motor fuel either to extend the fuel or to improve its octane rating or both. Unfortunately alcohols are hygroscopic and as a result, water becomes a component of the fuel. This can lead to phase separation and the formation of a water-rich layer which could have serious corrosion consequences. In an attempt to understand the phase-splitting in alcohol-petrol-water blends, phase equilibria in ternary systems (alcohol-hydrocarbon-water) have been determined by experiment. The phase equilibria in these ternary systems are also discussed in terms of modern theories of liquid mixtures and the UNIQUAC theory is applied to the "ethanol + benzene + water" ternary system. The alcohols are all the C₁, C₂, C₃ and C₄ alcohols, and the hydrocarbons include those typically found in petrol, e.g. cyclohexane, benzene and substituted benzenes.

The present doctoral thesis has been realized in accordance with the research line of Economy and Regulation in Telecommunications under the doctoral programme in Telecommunications of Universitat Politècnica de València. It has been developed on the basis of various research projects, especially the "Cooperation and Opportunity for Wireless Heterogeneous Networks Project" (TIN2010-21378-C02-02), which acted as my funding agent and the "S2EuNet-Security Project" . Mobile communications have undergone notable growth from their beginning up to the present day regarding devices and bandwidth available. Service providers have now to take the challenge of such increase. New technologies are being implemented to address the challenge and all of them belong to the world of mobile communications. This thesis will focus on the solutions provided by heterogeneous nets (HetNets) and, more speci¿cally, we will look at the Small Cells technology. It is starting to be widely deployed lately and allows for a visible increase in network capacity and a resulting enhancement in availability and coverage on the user side. Abundant research has proved that the integration of these technologies within markets is technically feasible. A marketing model is however still necessary which is able to prove its economic viability. A business model was laid out where a provider sets out to deploy small cells technology and stands as an incumbent service provider. The Theory of Games was used for the analysis of such models as it allows an insight of the decisions in equilibrium when entering into a competition among themselves and try the decisions of users need to be predicted. In this way we will manage to know the effect of such decisions over the pro¿ts of all the agents in the model. A clear picture will be thus obtained of the advantages of the implementation of the new technology in the market as well as of its effects over the incumbent service providers. This thesis intends to be a contribution towards the implementation of new technologies in the market of mobile technologies through the analysis of the competence between new service providers of Small Cells and an incumbent service providers along with the behaviour of the users of mobile communications. The result show that: users get a better service, the SSP pro¿ts are guaranteed and the entrance of the SSP improves the user comfort and social welfare. / Esta tesis se ha creado en el marco de la línea de investigación de Economía y Regulación de las Telecomunicaciones del programa de doctorado de Telecomunicaciones de la Universitat Politècnica de València, y se ha desarrollado en diferentes proyectos de investigación, en especial, el proyecto de "Cooperación yOportunismo enRedesde Acceso Inalámbricas y Heterogéneas" (TIN2010-21378-C02-02) y el proyecto S2EuNet-Security (FP7PEOPLE-2009- IRSES, 247083). Desde sus inicios las comunicaciones móviles han experimentado un gran crecimiento, tanto de dispositivos móviles como de cantidad de ancho de banda demandado, lo que ha provocado que los proveedores se encuentren con el desafío de hacer frente a este crecimiento. Para ello, se están implementando diferentes técnicas y tecnologías que se integran con el modeloactualdecomunicacionesmóviles.Enestatesisnoscentraremosenla solución que aportan las redes heterogéneas, especialmente en la tecnología de Small cells que se desplegado rápidamente en los últimos años y permite incrementar la capacidad de la red, así como obtener mejor disponibilidad y cobertura para los usuarios, pero falta un modelo de negocio claro donde se muestre su viabilidad económica. En esta tesis se plantea un modelo de negocio para un proveedor de servicio que despliega small cells y que compite como el proveedor de servicios incumbente. Para el análisis de este modelo se ha utilizado la Teoría de Juegos la cual ha permitido conocer las decisiones en equilibrio que toman los proveedores de servicio cuando compiten entre sí, así como las decisiones en equilibrio de los usuarios; de esta manera se ha obtenido el efecto de estas decisiones sobre los bene¿cios de todos los agentes del modelo y se han identi¿cado las ventajas y los inconvenientes que tiene la implementación de una nueva tecnología en el mercado. Esta tesis pretende ser una contribución al estudio de implementación de nuevas tecnologías en el mercado de comunicaciones móviles, más concretamente planteando modelos económicos que estudien su viabilidad a través del análisis de la competencia entre un nuevo proveedor se servicio de Small cells y el proveedor de servicio existente, y el comportamiento de los usuarios de comunicaciones móviles. Los resultados obtenidos muestran que los usuarios obtienen una mejor utilidad , el SSP siempre tiene unos bene¿cios garantizados, el MSP se ve obligado a competir y sus bene¿cios se ven perjudicados, además que la entrada del SSP mejora el bienestar de los usuarios y el bienestar social. / Aquesta tesi s'ha creat en el marc de la línia de recerca d'Economia i Regulació de les Telecomunicacions del programa de doctorat de Telecomunicacions de la Universitat Politècnica de València, i s'ha desenvolupat en diferents projectes de recerca, especialment, el projecte de Çooperació i Oportunisme en Xarxes d'Accés Sense ¿ls i Heterogènies"(TIN2010-21378-C02-02) i el projecte S2EuNet-Security (FP7PEOPLE-2009- IRSES, 247083). Des dels seus inicis les comunicacions mòbils han experimentat un gran creixement, tant de dispositius mòbils com de quantitat d'amplada de banda demandada, la qual cosa ha provocat que els proveïdors es troben amb el desa¿amentdeferfrontaaquestcreixement.Peraaixò,s'estanimplementant diferents tècniques i tecnologies que s'integren amb el model actual de comunicacions mòbils. En aquesta tesi ens centrarem en la solució que aporten les xarxes heterogènies, especialment a la tecnologia de Small cells que s'ha desplegat ràpidament en els últims anys i permet incrementar la capacitat de la xarxa, així com obtenir millor disponibilitat i cobertura per als usuaris, però falta un model de negoci clar on es mostre la seua viabilitat econòmica. En aquesta tesi es planteja un model de negoci per a un proveïdor de servei que desplega Small cells i que competeix com el proveïdor de serveis incumbent. Per a l'anàlisi d'aquest model s'ha utilitzat la Teoria de Jocs la qual ha permès conéixer les decisions en equilibri que prenen els proveïdors de servei quan competeixen entre si, així com les decisions en equilibri dels usuaris; d'aquesta manera s'ha obtingut l'efecte d'aquestes decisions sobre els bene¿cis de tots els agents del model i s'han identi¿cat els avantatges i els inconvenients que té la implementació d'una nova tecnologia al mercat. Aquesta tesi pretén ser una contribució a l'estudi d'implementació de noves tecnologies al mercat de comunicacions mòbils, més concretament plantejant models econòmics que estudien la seua viabilitat a través de l'anàlisi de la competència entre un nou proveïdor se servei de Small cells i el proveïdor de servei existent, i el comportament dels usuaris de comunicacions mòbils. Els resultats obtinguts mostren que els usuaris obtenen una millor utilitat, el SSP sempre té uns bene¿cis garantits, el MSP es veu obligat a competir i els seus bene¿cis es veuen perjudicats, a més que l'entrada del SSP millora el benestar dels usuaris i el benestar social. / Romero Chavarro, JC. (2017). Contribución al modelado y al análisis mediante Teoría de Juegos de la competencia entre operadores móviles en escenarios con tecnología "small cell" [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/85681 / TESIS

abstract: The field of cyber-defenses has played catch-up in the cat-and-mouse game of finding vulnerabilities followed by the invention of patches to defend against them. With the complexity and scale of modern-day software, it is difficult to ensure that all known vulnerabilities are patched; moreover, the attacker, with reconnaissance on their side, will eventually discover and leverage them. To take away the attacker's inherent advantage of reconnaissance, researchers have proposed the notion of proactive defenses such as Moving Target Defense (MTD) in cyber-security. In this thesis, I make three key contributions that help to improve the effectiveness of MTD. First, I argue that naive movement strategies for MTD systems, designed based on intuition, are detrimental to both security and performance. To answer the question of how to move, I (1) model MTD as a leader-follower game and formally characterize the notion of optimal movement strategies, (2) leverage expert-curated public data and formal representation methods used in cyber-security to obtain parameters of the game, and (3) propose optimization methods to infer strategies at Strong Stackelberg Equilibrium, addressing issues pertaining to scalability and switching costs. Second, when one cannot readily obtain the parameters of the game-theoretic model but can interact with a system, I propose a novel multi-agent reinforcement learning approach that finds the optimal movement strategy. Third, I investigate the novel use of MTD in three domains-- cyber-deception, machine learning, and critical infrastructure networks. I show that the question of what to move poses non-trivial challenges in these domains. To address them, I propose methods for patch-set selection in the deployment of honey-patches, characterize the notion of differential immunity in deep neural networks, and develop optimization problems that guarantee differential immunity for dynamic sensor placement in power-networks. / Dissertation/Thesis / Doctoral Dissertation Computer Science 2020