Dados um espaço de medida (X;A;m) e números reais p,q>1 com 1/p+1/q=1, o Teorema de Representação de Riesz afirma que Lq(X;A;m) é o dual topológico de Lp(X;A;m) e que Loo(X;A; m) é o dual topológico de L1(X;A;m) se o espaço (X;A;m) for sigma-finito. Observamos que a sigma-finitude de (X;A;m) é condição suficiente mas não necessária para que Loo(X;A;m) seja o dual de L1(X;A;m). Os contra-exemplos tipicamente apresentados para essa última identificação são \"triviais\", no sentido de que desaparecem se \"consertarmos\" a medida , transformando-a numa medida perfeita. Neste trabalho apresentamos condições sufcientes mais fracas que sigma-finitude a fim de que Loo(X;A;m) e o dual de L1(X;A;m) possam ser isometricamente identificados. Além disso, introduzimos um invariante cardinal para espaços de medida que chamaremos a dimensão do espaço e mostramos que se o espaço (X;A;m) for de medida perfeita e tiver dimensão menor ou igual à cardinalidade do continuum então uma condição necessária e suficiente para Loo(X;A;m) seja o dual de L1(X;A;m) é que X admita uma decomposição. / Given a measure space (X;A;m) and real numbers p,q>1 with 1/p+1/q=1, the Riesz Representation Theorem states that Lq(X;A;m) is the topological dual space of Lp(X;A;m) and that Loo(X;A; m) is the topological dual space of L1(X;A;m) if (X;A; m) is sigma-finite. We observe that the sigma-finiteness of (X;A;m) is a suficient but not necessary condition for Loo(X;A;m) to be the dual of L1(X;A;m). The counter-examples that are typically presented for Loo(X;A;m) = L1(X;A;m)* are \"trivial\", in the sense that they vanish if we fix the measure , making it into a perfect measure. In this work we present suficient conditions weaker than sigma-finiteness in order that Loo(X;A; m) and L1(X;A;m)* can be isometrically identified. Moreover, we introduce a cardinal invariant for measure spaces which we call the dimension of the space and we show that if the space (X;A;m) has perfect measure and dimension less than or equal to the cardinal of the continuum then a necessary and suficient condition for Loo(X;A;m) = L1(X;A;m)* is that X admits a decomposition.

Nous étudions, dans la première partie de notre thèse, les polysimplexes d’un espace euclidien de dimension quelconque, c’est-à-dire les objets consistant en une juxtaposition de simplexes réguliers (de tétraèdres si la dimension est 3) accolés le long de leurs faces. Nous étudions principalement le groupe des symétries de ces polysimplexes. Nous présentons une façon de représenter un polysimplexe à l’aide d’un diagramme. Ceci fournit une classification complète des polysimplexes à similitude près. De plus, le groupe des symétries se déduit du groupe des automorphismes du diagramme. Il découle en particulier de notre étude qu’en dimension supérieure à 2, une telle structure ne possède jamais deux faces parallèles et ne contient jamais de circuit fermé de simplexes.<p><p>Dans la seconde partie de notre thèse, nous abordons un problème classique de combinatoire :l’énumération des pavages d’un rectangle mxn à l’aide de dominos. Klarner et Pollack ont montré qu’en fixant m la suite obtenue vérifie une relation de récurrence linéaire à coefficients constants. Nous établissons une nouvelle méthode nous permettant d’obtenir la fonction génératrice correspondante et la calculons pour m <= 16, alors qu’elle n’était connue que pour m <= 10.<p> / Doctorat en Sciences / info:eu-repo/semantics/nonPublished

This master's thesis aims to compare Horacio Quiroga's short story with a general theory of the short story and to juxtapose it with Quiroga's own Ten Rules for the Perfect Storyteller. The first theoretical part looks at the short story from the point of view of literary history with a special focus on the differences between a short story and a novel. It goes on to give a short overview of the literary development in Latin America, outlining specific features of the given area and their influence on Horacio Quiroga's works. A separate chapter covers the Hispanic - American fantasy short story, its general principles and some examples of Horacio Quiroga's works. In the next chapter the paper refers to Quiroga's essays concerning theories of the short story, particularly Ten Rules for the Perfect Storyteller, aiming to introduce the theoretical concept of Quiroga's art of storytelling. Ten Rules for the Perfect Storyteller provides the paper with the background to interpret a number of selected Quiroga's short stories as well as to compare the theories of the short story between Horacio Quiroga and Edgar Allan Poe. Having briefly outlined the context of Quiroga's complete work, the paper identifies the main recurring themes and touches upon Quiroga's character in his short stories set in the...

We are using organic small molecules as absorbing material to investigate coherent perfect absorption in layered thin-film structures. Therefore we realize strongly asymmetric resonator structures with a high optical quality dielectric distributed Bragg reflector and thermally evaporated wedged organic materials on top. We investigate the optical properties of these structures systematically by selective optical pumping and probing of the structure. By shifting the samples along the wedge, we demonstrate how relations of phase and amplitude of all waves can be tuned to achieve coherent perfect absorption. Thus almost all incident radiation dissipates in the thin organic absorbing layer. Furthermore, we show how these wedged structures on a high-quality reflective dielectric mirror can be used to determine optical dispersion relations of absorbing materials in a broad spectral range. This novel approach does not require any specific a priori knowledge on the absorbing film.

The popularity of mobile devices and location-based services (LBS) have created great concerns regarding the location privacy of the users of such devices and services. Anonymization is a common technique that is often being used to protect the location privacy of LBS users. This technique assigns a random pseudonym to each user and these pseudonyms can change over time. Here, we provide a general information theoretic definition for perfect location privacy and prove that perfect location privacy is achievable for mobile devices when using the anonymization technique appropriately. First, we assume that the user’s current location is independent from her past locations. Using this i.i.d model, we show that if the pseudonym of the user is changed before O(n2/(r−1)) number of anonymized observations is made by the adversary for that user, then she has perfect location privacy, where n is the number of users in the network and r is the number of all possible locations that the user might occupy. Then, we model each user’s movement by a Markov chain so that a user’s current location depends on his previous locations, which is a more realistic model when approximating real world data. We show that perfect location privacy is achievable in this model if the pseudonym of the user is changed before O(n2/(|E|−r)) anonymized observations is collected by the adversary for that user where |E| is the number of edges in the user’s Markov model.

The present work reports a study related to the potential improvement of the energy performances of a heat pump based heating system for a Swedish single-family house. The analysis is focused on the design of new rule-based control strategies which employ perfect predictions of weather forecast and human behaviour information. In particular, the considered signals are the outdoor temperature, the solar radiation, the internal gain due to inhabitants’ activities and the Domestic Hot Water (DHW) consumption. The study is performed by means of the TRNSYS® simulation software in which the model of the heating system is implemented. More specifically, it is composed by a Ground Source Heat Pump (GSHP) unit, a stratified storage tank of three hundred litres and the building element. The performances of the developed control logics are evaluated using a degree-minute on/off controller as reference case. The results show that the improved control logics yield to an increase of the energy efficiency of the system as well as an enhancement of the indoor and DHW temperatures stability. / EffSys Expand P18: Smart Cotnrol Strategies for Heat Pump Systems

The present work deals with a study related to the analysis of weather data for heat pump system control improvement based on both instantaneous and forecasted measurements. In particular, the analysis is firstly focused on the comparison of multiple weather sources for the assessment of weather forecast uncertainties, based on the evaluation of errors in prediction with respect to measured values. Afterwards, the results are compared with the ones related to persistent predictions methods that assumes the state of the atmosphere to be stationary over the considered time interval. The development and testing of a new preliminary “predictive” control logic is also performed, thanks to TRNSYS numerical simulations, considering a typical Swedish single-family house located in Stockholm, with the aim of optimizing the operation of a heat pump heating system based on solar radiation prediction to yield energy and cost savings. With the crucial points of accuracy and precision by which the local weather processes can be predicted, the same TRNSYS model is run accounting for perfect predictions and solar radiation forecasted values. From this perspective, given the fact that forecast of solar radiation are usually absent within most of the weather forecast datasets, a deep analysis is also performed on hourly measurements of solar radiation to define a simple and effective methods to calculate hourly solar radiation predictions. The results show that, when a short-time horizon is considered, persistent predictions allow to provide forecasts with a sufficient accuracy, whereas, when longer horizon time are considered, significantly higher errors are calculated when persistent prediction techniques are adopted. Independently of the uncertainties considered for weather forecasts, the improved control logics demonstrated a potential for energy savings and improvements in indoor temperature stability when compared with a reference case of variable speed compressor with PID controller. / EffSys Expand P18: Smart Cotnrol Strategies for Heat Pump Systems

We show that Einstein’s gravitational field equations for the Friedmann- Robertson-Lemaître-Walker (FRLW) and for two conformal versions of the Bianchi I and Bianchi V perfect fluid scalar field cosmological models, can be equivalently reformulated in terms of a single equation of either generalized Ermakov-Milne- Pinney (EMP) or (non)linear Schrödinger (NLS) type. This work generalizes or presents an alternative to similar reformulations published by the authors who inspired this thesis: R. Hawkins, J. Lidsey, T. Christodoulakis, T. Grammenos, C. Helias, P. Kevrekidis, G. Papadopoulos and F.Williams. In particular we cast much of these authors’ works into a single framework via straightforward derivations of the EMP and NLS equations from a simple linear combination of the relevant Einstein equations. By rewriting the resulting expression in terms of the volume expansion factor and performing a change of variables, we obtain an uncoupled EMP or NLS equation that is independent of the imposition of additional conservation equations. Since the correspondences shown here present an alternative route for obtaining exact solutions to Einstein’s equations, we reconstruct many known exact solutions via their EMP or NLS counterparts and show by numerical analysis the stability properties of many solutions.

<p>Similar to thermodynamic phase transitions in matter, readily apparent changes in optical response arise in the transition from isotropic to anisotropic optical phases. Treating the anisotropy of the dielectric permittivity as a control parameter, which changes continuously from zero to a nonzero finite value at the transition, in this work we describe the resulting effect on light propagation. </p> <p><br></p> <p>We begin by investigating a simple case of the manifestations of such optical transition in lossy media. In the presence of loss, isotropic materials do not support Brewster phenomenon, however, if one changes the anisotropy continuously, the exact zero in the reflection at the Brewster incidence angle is recovered. Next, in the case of uniaxial anisotropy, we uncover dramatic changes in far-field thermal radiation induced by the transitions between metal, dielectric, and hyperbolic optical regimes that can be observed in the same material. We demonstrate that continuous evolution between different ''phases'' in the electromagnetic response imprints a characteristic signature in the far-field thermal emission. Finally, we show that the evolution of the optical anisotropy from uniaxial to biaxial symmetry brings qualitatively new optical modes which are different from the conventional propagating and evanescent fields. These emergent ''ghost'' waves offer a unique way to control mode interactions in optical systems. Our work uncovers the connection between the macroscopic properties of the optical materials and the transitions between different regimes of the electromagnetic response in these media. At last, we propose a range of potential applications of the resulting phenomena, from perfect absorption in lossy media to thermal radiation and optical sensing.</p>

The forefront of game playing Artificial Intelligence (AI) has for the better part of 21st century been using an algorithm called Alpha-Beta Pruning (Alpha-Beta). In 2017, DeepMind launched a new AI, based on the algorithm Monte Carlo Tree Search (MCTS), which defeated the former Alpha-Beta based chess AI champion Stockfish. This accomplishment fueled up more excitement and interest for using MCTS to develop more complex and better performing game playing AI.This paper aims to compare the strengths of MCTS and Alpha-Beta by allowing them to play against each other in a classic game with no available robust AI - the Fox Game.The results showed an evident victory for the Alpha-Beta AI. Therefore, Alpha-Beta is the better suited algorithm for developing a simple AI for the Fox Game. Further optimizations would enhance the performance of both algorithms but it is unclear which of the algorithms would benefit from it the most. / Framkanten av Artificiell Intelligens (AI) som spelar spel har i större delen av 2000-talet använt sig av en algorithm vid namn Alpha-Beta-beskärning (Alpha-Beta). Denna bedrift höjde intresset för att använda MCTS i syfte att utveckla mer komplexa och bättre spelande AI.Denna rapport har som mål att jämföra styrkor hos MCTS och Alpha-Beta genom att låta dem spela mot varandra i ett klassiskt spel utan någon tillgänglig AI - Rävspelet. Resultaten visade på en klar seger för Alpha-Beta AI:n. Därför är Alpha-Beta den bättre lämpade algoritmen för att skapa en simpel AI. Fler optimiseringar hade förbättrat spelstyrkan hos bägge algoritmerna med det är oklart vilken av algoritmerna som hade gynnat mest utav det. / Kandidatexjobb i elektroteknik 2022, KTH, Stockholm