When analyzing situations involving intelligent agents with objectives, it can be helpful to use discrete games as models. Within such game models the synthesis of winning strategies is of interest, and many algorithmic methods have been developed for this purpose. This project focused on a less tractable game type, involving a coalition of players without the ability to communicate. For this type of game we propose two methods for exploring knowledge-based strategies. One is an extension of the previously developed Multiplayer Knowledge- Based Subset Construction with the additional assumption of action observability within the coalition. The other is a novel method called Epistemic Expansion, which assumes that the coalition coordinates before playing the game. We demonstrate how these methods can be used to help find winning strategies in example games with relevant properties. / Diskreta spel kan utgöra lämpliga modeller för många situationer där intelligenta spelare är inblandade. I dessa modellspel är det av intresse att hitta vinnande strategier och många algoritmer har utvecklats i detta syfte. I detta projekt undersöker vi spel i vilka en koalition av spelare med ett gemensamt mål ska samarbeta utan kommunikation. För att underlätta syntesen av vinnande strategier är det lämpligt att följa hur spelarnas kunskapsläge utvecklas under spelets gång. Vi föreslår två kunskapsbaserade konstruktioner för att modellera två skilda antaganden. Det första är att spelarna kan observera varandras handlingar, och det andra är att koalitionen har möjlighet att skapa en koordinerad strategi innan spelet börjar. Vi visar hur dessa konstruktioner kan användas för att syntetisera vinnande strategier i utvalda exempelspel. / Kandidatexjobb i elektroteknik 2020, KTH, Stockholm

The behavior of repairable equipment is often modeled under assumptions such as perfect repair, minimal repair, or negligible repair. However the majority of equipment behavior does not fall into any of these categories. Rather, repair actions do take time and the condition of equipment following repair is not strictly "as good as new" or "as bad as it was" prior to repair. Non-homogeneous processes that reflect this type of behavior are not studied nearly as much as the minimal repair case, but they far more realistic in many situations. For this reason, the quasi-renewal process provides an appealing alternative to many existing models for describing a non-homogeneous process. A quasi-renewal process is characterized by a parameter that indicates process deterioration or improvement by falling in the interval [0,1) or (1,Infinity) respectively. This parameter is the amount by which subsequent operation or repair intervals are scaled in terms of the immediately previous operation or repair interval. Two equivalent expressions for the point availability of a system with operation intervals and repair intervals that deteriorate according to a quasi-renewal process are constructed. In addition to general expressions for the point availability, several theoretical distributions on the operation and repair intervals are considered and specific forms of the quasi-renewal and point availability functions are developed. The two point availability expressions are used to provide upper and lower bounds on the approximated point availability. Numerical results and general behavior of the point availability and quasi-renewal functions are examined. The framework provided here allows for the description and prediction of the time-dependent behavior of a non-homogeneous process without the assumption of limiting behavior, a specific cost structure, or minimal repair. / Ph. D.

We study games where a team of agents needs to collaborate against an adversary to achieve a common goal. The agents make their moves simultaneously, and they have different perceptions about the system state after each move, due to different sensing capabilities. Each agent can only act based on its own experiences, since no communication is assumed during the game. However, before the game begins, the agents can agree on some strategy. A strategy is winning if it guarantees that the agents achieve their goal regardless of how the opponent acts. Identifying a winning strategy, or determining that none exists, is known as the strategy synthesis problem. In this thesis, we only consider a simple objective where the agents must force the game into a given state. Much of the literature is focused on strategies that either rely on that the agents (a) can remember everything that they have perceived or (b) can only remember the last thing that they have perceived. The strategy synthesis problem is (in the general case) undecidable in (a) and has exponential running time in (b). We are interested in the middle, where agents can have finite memory. Specifically, they should be able to keep a finite-state machine, which they update when they make new observations. In our case, the internal state of each agent represents its knowledge about the state of affairs. In other words, an agent is able to update its knowledge, and act based on it. We propose an algorithm for constructing the finite-state machine for each agent, and assigning actions to the internal states before the game begins. Not every winning strategy can be found by the algorithm, but we are convinced that the ones found are valid ones. An important building block for the algorithm is the knowledge-based subset construction (KBSC) used in the literature, which we generalise to games with multiple agents. With our construction, the game can be reduced to another game, still with uncertain state information, but with less or equal uncertainty. The construction can be applied arbitrarily many times, but it appears as if it stabilises (so that no new knowledge is gained) after only a few steps. We discuss this and other interesting properties of our algorithm in the final chapters of this thesis. / Vi studerar spel där ett lag agenter behöver samarbeta mot en motståndare för att uppnå ett mål. Agenterna agerar samtidigt, och vid varje steg av spelet så har de olika uppfattning om spelets tillstånd. De antas inte kunna kommunicera under spelets gång, så agenterna kan bara agera utifrån sina egna erfarenheter. Innan spelet börjar kan agenterna dock komma överrens om en strategi. En sådan strategi är vinnande om den garanterar att agenterna når sitt mål oavsett hur motståndaren beter sig. Att hitta en vinnande strategi är känt som syntesproblemet. I den här avhandlingen behandlar vi endast ett enkelt mål där agenterna måste tvinga in spelet i ett givet tillstånd. Mycket av litteraturen handlar om strategier där agenterna antingen antas (a) kunna minnas allt som de upplevt eller (b) bara kunna minnas det senaste de upplevt. Syntesproblemet är (i det generella fallet) oavgörbart i (a) och tar exponentiell tid i (b). Vi är intressede av fallet där agenter kan ha ändligt minne. De ska kunna ha en ändlig automat, som de kan uppdatera när de får nya observationer. I vårt fall så representerar det interna tillståndet agentens kunskap om spelets tillstånd. En agent kan då uppdatera sin kunskap och agera utifrån den. Vi föreslår en algoritm som konstruerar en ändlig automat åt varje agent, samt instruktioner för vad agenten ska göra i varje internt tillstånd. Varje vinnande strategi kan inte hittas av algoritmen, men vi är övertygade om att de som hittas är giltiga. En viktig byggsten är den kunskapsbaserade delmängskonstruktionen (KBSC), som vi generaliserar till spel med flera agenter. Med vår konstruktion kan spelet reduceras till ett annat spel som har mindre eller lika mycket osäkerhet. Detta kan göras godtyckligt många gånger, men det verkar som om att ingen ny kunskap tillkommer efter bara några gånger. Vi diskuterar detta vidare tillsammans med andra intressanta egenskaper hos algoritmen i de sista kapitlen i avhandlingen.

This thesis develops a macroeconomic model with monopolistic competition and considers the search cost for consumption in order to analyze how advertising influences the major macroeconomic variables and causes the entry barriers. In the short run, we find that advertising will raise aggregate output. The higher the sensitivity of advertising elasticity of search cost, the greater the rising of aggregate output. Further, whether the price level rise or fall is dependent on the magnitude of the advertising elasticity of search cost. The higher sensitivity of this elasticity on advertising, the higher the price level. Moreover, advertising does not influence the market power in the short run. In the long run, we find that whether advertising causes the barriers to entry is determined by the sensitivity of the advertising elasticity of search cost. When this elasticity is small, advertising will create the entry barriers and further strengthen the monopoly power for firms. Furthermore, how advertising affects the price level and aggregate output depends not only on the advertising elasticity of search cost, but also the sensitivity of the elasticity of substitution on the number of firms.

Paper [I] Using a unique and highly detailed data set on energy consumption at the appliance-level for 200 Swedish households, seemingly unrelated regression (SUR)-based end-use specific load curves are estimated. The estimated load curves are then used to explore possible restrictions on load shifting (e.g. the office hours schedule) as well as the cost implications of different load shift patterns. The cost implications of shifting load from "expensive" to "cheap" hours, using the Nord Pool spot prices as a proxy for a dynamic price, are computed to be very small; roughly 2-4% reduction in total daily costs from shifting load up to five hours ahead, indicating small incentives for households (and retailers) to adopt dynamic pricing of electricity. Paper [II] Using a detailed data set on appliance-level electricity consumption at the hourly level, we provide the first estimates of hourly and end-use-specific income elasticities for electricity. Such estimates are informative about how consumption patterns in general, and peak demand in particular, will develop as households’ income changes. We find that the income elasticities are highest during peak hours for kitchen and lighting, with point estimates of roughly 0.4, but insignificant for space heating. Paper [III] In this paper, I estimate the price elasticity of electricity as a function of the choice between fixed-price and variable-price contracts. Further, assuming that households have imperfect information about electricity prices and usage, I explore how media coverage of electricity prices affects electricity demand, both by augmenting price responsiveness and as a direct effect of media coverage on electricity demand, independent of prices. I also address the endogeneity of the choice of electricity contract. The parameters in the model are estimated using unique and detailed Swedish panel data on monthly household-level electricity consumption. I find that price elasticities range between −0.025 and −0.07 at the mean level of media coverage, depending on contract choice, and that households with monthly variation in electricity prices respond more to prices when there is extensive media coverage of electricity prices. When media coverage is high, for example 840 news articles per month (which corresponds to the mean plus two standard deviations), the price elasticity is −0.12, or 1.7 times the elasticity at the mean media coverage. Similarly, media coverage is also found to have a direct effect on electricity demand. Paper [IV] I explore how households switch between fixed-price and variable-price electricity contracts in response to variations in price and temperature, conditional on previous contract choice. Using panel data with roughly 54000 Swedish households, a dynamic probit model is estimated. The results suggest that the choice of contract exhibits substantial state dependence, with an estimated marginal effect of previous contractchoiceof0.96, andthattheeffectofvariationinpricesandtemperatureonthechoice of electricity contract is small. Further, the state dependence and price responsiveness are similar across housing types, income levels and other dimensions. A plausible explanation of these results is that transaction costs are larger than the relatively small cost savings from switching between contracts.

Motivé par l'étude de tissus biologiques, ce travail contribue aux développements d'outils numériques permettant de prédire la réponse mécanique de matériaux hétérogènes non linéaires dans lesquels les énergies d'interfaces deviennent prépondérantes. Ainsi, une méthode d'homogénéisation multi échelle combinée à une technique de réduction de modèle basée sur la décomposition orthogonale aux valeurs propres est proposée dans un cadre thermique et hyperélastique. Les énergies d'interfaces entre les différentes phases des composites sont décrites par un modèle d'interface cohérent et prises en compte numériquement par une approche liant la méthode des éléments finis étendus et la méthode level-set. Une étude de l'étalement d'une cellule vivante entre deux lamelles fixes est ensuite réalisée. Les deux modèles utilisés pour les simulations montrent que l'assemblage cortex d'actine-membrane plasmique ne joue qu'un rôle minime dans la réponse mécanique cellulaire / Motivated by the study of biological tissues, this work contributes to developing numerical tools to predict the mechanical response of nonlinear heterogeneous materials in which the energies of interfaces can no longer be ignored. First, a computational homogenization strategy combined with a model reduction technique based on the proper orthogonal decomposition is implemented in the cases of large elastic deformations and highly nonlinear conduction. The interfaces between the different phases of a composite are described by means of a coherent interface model and taken into account numerically by an extended finite element method in tandem with a level-set technique. Finally, experimental results of single cell spreading between two fixed parallel microplates are exploited through finite element modelling. Our two models show that the bilayer membrane and the actin cortex do not play a significant role in the cell mechanical response

The objective of this thesis is to examine real exchange rate volatility, with a particular focus on investigating the causes of exchange rate jumps. While the predominant approach in the literature is to examine the interaction between nominal rigidities and nominal shocks, this thesis examines the volatility that arises from real rigidities and shocks. Trying to better understand the transmission of real shocks to the exchange rate is a worthwhile task, given the substantial evidence that these shocks and rigidities are important for explaining other economic fluctuations. This thesis develops theoretical models that examine the contributions of specific real rigidities to exchange rate volatility. Chapter 1 introduces our baseline specification - a frictionless model, with the exception of capital adjustment costs. This baseline generates very mild exchange rate fluctuations. Additional rigidities are required to generate volatility of the magnitude that is typically observed. Chapter 2 finds that introducing imperfect asset substitutability - specifically, home asset bias - goes a little towards achieving this. When investors are biased, the exchange rate must adjust by more to equilibrate asset markets. This greater burden of adjustment on the exchange rate along the short run path typically translates to larger jumps after shocks. Similarly, Chapter 3 shows that augmenting the baseline with banks and financial frictions raises exchange rate volatility. The key point is that, in the presence of financial frictions, there is a risk premium that widens after negative shocks, increasing the required adjustment of the exchange rate. A fourth chapter extends Chapter 3 and shows that unconventional credit policy, while beneficial in some respects, nonetheless entails nontrivial costs because it invites moral hazard by encouraging banks to be more highly leveraged, which increases exchange rate and consumption volatility. So, the overall message is that, in the presence of plausible real frictions - including (i) capital adjustment costs, (ii) imperfect asset substitutability, and (iii) financial frictions - real shocks can generate a plausibly significant degree of real exchange rate volatility. This thus posits an additional explanation of exchange rate jumps that complements the predominantly monetary literature.

This theses is dedicated to the use of the verbal paradigms hablara and hablase in contemporary Spanish. We demonstrate that due to historical reasons the usage of paradigm hablara is much wider than that of hablase, which can be used only in the subjunctive meaning. According to the valid linguistic norm, the paradigm hablara (and not hablase) can be used instead of the Past Perfect (although it is not recommended). The same is evidenced with the conditional tense of the modal verbs querer, deber and poder as well as with the main clause of the unreal conditional clauses in the present tense. This means that these two verb paradigms can be arbitralily substituted only when used in the subjunctive function. On the basis of our own frecuency analysis of twenty most used Spanish verbs in the language corpus CREA, we prove that the frecuency of the hablase on average 18% in Spain and 10% in Latin America. Our analysis of this corpus material does not confirm the statement of some linguists that the frecuency of -se form is generally slightly higher in negative sentences. However, our analysis of a parallel corpus InterCorp seems to indicate that it is higher (by 7%) after the conditional conjunction ‚si'.

Cette thèse étudie le système de distribution alimentaire au Vietnam fondée sur une approche de concurrence imparfaite. Le premier chapitre analyse le comportement de marché des intermédiaires dans le système de distribution alimentaire traditionnel. Nous modélisons le comportement des intermédiaires dans tous les cas de compétition de marché afin d'identifier l'impact du pouvoir de marché sur les producteurs alimentaires en amont, et sur les consommateurs en aval du système de distribution alimentaire traditionnel.La relation compétitive entre les différents circuits de distribution alimentaire est étudiée dans le second chapitre. Nous modélisation la compétition entre les systèmes de distribution alimentaire traditionnelle et moderne. Nous examinons la condition de coexistence qui permet aux deux circuits d'être active dans chaque cas spécifique de compétition de marché.Le troisième chapitre étudie le choix de circuit optimal des agriculteurs quand les coopératives agricoles soutiennent les petits producteurs dans l'accès au système de distribution alimentaire moderne. Nous introduisons deux circuits de distribution verticalement liés par la demande. Nous étudions le flux de quantité des petits producteurs aux consommateurs au moyen d'un équilibre de Nash, et nous abordons la question de la distribution des agriculteurs par un équilibre de libre entrée.Finalement, le quatrième chapitre analyse l'effet direct de la politique sur le système de distribution alimentaire. Nous proposons le modèle théorique de la réforme agraire, et étudions son impact sur le système de distribution alimentaire. / This dissertation studies the food distribution system in Viet Nam based on an imperfect competition approach.The first chapter analyzes the market behavior of the intermediaries in the traditional food distribution system. We model the intermediary behavior in all cases of market competition to recognize the impact of their market power on the food producers in the upstream, and on the consumers in the downstream of the traditional food distribution system.The competitive relationship between different food distribution channels is studied in the second chapter. We model the competition between the traditional and the modern food distribution system to analyze how the market behaves at equilibrium. We moreover investigate the coexistence condition which allows both channels to be active in each specific case of market competition.The third chapter studies the optimal channel choice of the farmers when agricultural cooperatives support these small producers accessing the modern food distribution system. We introduce two distribution channel vertically linked by demand. We study the quantity flow from small producers to the consumers by mean of a Nash equilibrium and address the question of the distribution of the farmers by a free entry equilibrium.Eventually, the fourth chapter analyzes the policy implication directly toward the food distribution system. We propose the theoretical model of land reform and study its impact on the food distribution system.

Os modelos de sistemas reparáveis usuais são os de reparo mínimo, perfeito e imperfeito, sendo que, na literatura, o modelo de reparo mínimo é o mais explorado. Em sistemas reparáveis é comum que componentes do mesmo tipo sejam estudados e nestes casos é relevante verificar a heterogeneidade entre eles. Segundo Vaupel et al. (1979), os métodos padrões em análise de dados de sistemas reparáveis ignoram a heterogeneidade não observada e em alguns casos esta deveria ser considerada. Tal variabilidade pode ser estimada a partir dos modelos de fragilidade, caracterizados pela utilização de um efeito aleatório. Propõe-se o modelo de reparo mínimo com fragilidade, afim de estimar a heterogeneidade não observada entre sistemas. Para este modelo foi realizado um estudo e simulação como objetivo de analisar as propriedades frequentistas do processo de estimação. A aplicação em um conjunto de dados reais mostrou a aplicabilidade do modelo proposto, em que a estimação dos parâmetros foram determinadas a partir das abordagens de máxima verossimilhança e Bayesiana. / The usual models in repair able systems are minimal, perfect and imperfect repair, and, in the literature, the minimum repair model is the most explored. In repair able systems it is common that the same type of components are studied and in these cases is relevant to verify the heterogeneity between them. According to Vaupel et al. (1979), the standard methods for analysis of repair able systems data ignore the heterogeneity not observed and in some cases this should be considered. Such variability can be estimated from frailty models, characterized by using a random effect. It is proposed that the minimum repair model with frailty in order to estimate the heterogeneity not observed between systems. For this model it was conducted a simulation study in order to analyze the frequentist properties of the estimation process. The application of a real data set showed the applicability of the proposed model, in which the estimation of the parameters were determined from maximum likelihood and Bayesian approaches.