Every normal logic program has a 2-valued semantics: theory, extensions, applications, implementations

Trabalho apresentado no ��mbito do Doutoramento em Inform��tica, como requisito parcial para obten����o do grau de Doutor em Inform��tica

Health care marketing: the theory of planned behavior applied to patients' choise between private and public providers in the portuguese health care system.

Dissertation submitted in partial fulfillment of the requirements for degree of Master in Statistics and Information Management.

Depositions of rulers in the later middle ages: on the theory of th "useless ruler" and its practical utilization

pp. 157-168

���The past is a foreign country���? Acculturation theory and the anthropology of globalization

Etnogr��fica, 15 (2): 313-336

Coalition of distributed generation units to Virtual Power Players - a game theory approach

Smart Grids (SGs) have emerged as the new paradigm for power system operation and management, being designed to include large amounts of distributed energy resources. This new paradigm requires new Energy Resource Management (ERM) methodologies considering different operation strategies and the existence of new management players such as several types of aggregators. This paper proposes a methodology to facilitate the coalition between distributed generation units originating Virtual Power Players (VPP) considering a game theory approach. The proposed approach consists in the analysis of the classifications that were attributed by each VPP to the distributed generation units, as well as in the analysis of the previous established contracts by each player. The proposed classification model is based in fourteen parameters including technical, economical and behavioural ones. Depending of the VPP strategies, size and goals, each parameter has different importance. VPP can also manage other type of energy resources, like storage units, electric vehicles, demand response programs or even parts of the MV and LV distribution network. A case study with twelve VPPs with different characteristics and one hundred and fifty real distributed generation units is included in the paper.

Decision Support for Energy Contracts Negotiation with Game Theory and Adaptive Learning

This paper presents a decision support methodology for electricity market players��� bilateral contract negotiations. The proposed model is based on the application of game theory, using artificial intelligence to enhance decision support method���s adaptive features. This model is integrated in AiD-EM (Adaptive Decision Support for Electricity Markets Negotiations), a multi-agent system that provides electricity market players with strategic behavior capabilities to improve their outcomes from energy contracts��� negotiations. Although a diversity of tools that enable the study and simulation of electricity markets has emerged during the past few years, these are mostly directed to the analysis of market models and power systems��� technical constraints, making them suitable tools to support decisions of market operators and regulators. However, the equally important support of market negotiating players��� decisions is being highly neglected. The proposed model contributes to overcome the existing gap concerning effective and realistic decision support for electricity market negotiating entities. The proposed method is validated by realistic electricity market simulations using real data from the Iberian market operator���MIBEL. Results show that the proposed adaptive decision support features enable electricity market players to improve their outcomes from bilateral contracts��� negotiations.

Fiscal decentralisation and economic theory

There is no complete overview or discussion of the literature of the economics of federalism and fiscal decentralization, even though scholarly interest in the topic has been increasing significantly over recent years. This paper provides a general, brief but comprehensive overview of the main insights from the literature on fiscal federalism and decentralization. In doing so, literature on fiscal federalism and decentralization is grouped into two main approaches: ���first generation of theories��� and ���second generation of theories���.

Understanding the internet banking adoption by Portuguese customers - a unified theory of acceptance and use of technology and perceived risk application.

Trabalho de Projeto apresentado como requisito parcial para obten����o do grau de Mestre em Estat��stica e Gest��o de Informa����o

Men���s purchase intention of shampoo: a model based on the theory of planned behavior and self-concept

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Management from the NOVA ��� School of Business and Economics

Three essays on game theory and bargaining

A PhD Dissertation, presented as part of the requirements for the Degree of Doctor of Philosophy from the NOVA - School of Business and Economics

Spiteful Strategies. The ontogeny and the practice of spite in human interaction: an experimental game theory approach and empirical applications

As estrat��gias de malevol��ncia implicam que um indiv��duo pague um custo para infligir um custo superior a um oponente. Como um dos comportamentos fundamentais da sociobiologia, a malevol��ncia tem recebido menos aten����o que os seus pares o ego��smo e a coopera����o. Contudo, foi estabelecido que a malevol��ncia �� uma estrat��gia vi��vel em popula����es pequenas quando usada contra indiv��duos negativamente geneticamente relacionados pois este comportamento pode i) ser eliminado naturalmente, ou ii) manter-se em equil��brio com estrat��gias cooperativas devido �� disponibilidade da parte de indiv��duos malevolentes de pagar um custo para punir. Esta tese prop��e compreender se a propens��o para a malevol��ncia nos humanos �� inerente ou se esta se desenvolve com a idade. Para esse efeito, considerei duas experi��ncias de teoria de jogos em crian��as em ambiente escolar com idades entre os 6 e os 22 anos. A primeira, um jogo 2x2 foi testada com duas variantes: 1) um pr��mio foi atribu��do a ambos os jogadores, proporcionalmente aos pontos acumulados; 2), um pr��mio foi atribu��do ao jogador com mais pontos. O jogo foi desenhado com o intuito de causar o seguinte dilema a cada jogador: i) maximizar o seu ganho e arriscar ter menos pontos que o advers��rio; ou ii) decidir n��o maximizar o seu ganho, garantindo que este n��o era inferior ao do seu advers��rio. A segunda experi��ncia consistia num jogo do ditador com duas op����es: uma escolha ego��sta/altru��sta (A), onde o ditador recebia mais ganho, mas o seu recipiente recebia mais que ele e uma escolha malevolente (B) que oferecia menos ganhos ao ditador que a A mas mais ganhos que o recipiente. O dilema era que se as crian��as se comportassem de maneira ego��sta, obtinham mais ganho para si, ao mesmo tempo que aumentavam o ganho do seu colega. Se fossem malevolentes, ent��o prefeririam ter mais ganho que o seu colega ao mesmo tempo que tinham menos para eles pr��prios. As experi��ncias foram efetuadas em escolas de duas ��reas distintas de Portugal (continente e A��ores) para perceber se as prefer��ncias malevolentes aumentavam ou diminu��am com a idade. Os resultados na primeira experi��ncia sugerem que (1) os alunos compreenderam a primeira variante como um jogo de coordena����o e comportaram-se como maximizadores, copiando as jogadas anteriores dos seus advers��rios; (2) que os alunos repetentes se comportaram preferencialmente como malevolentes, mais frequentemente que como maximizadores, com especial ��nfase para os alunos de 14 anos; (3) maioria dos alunos comportou-se reciprocamente desde os 12 at�� aos 16 anos de idade, ap��s os quais come��aram a desenvolver uma maior toler��ncia ��s escolhas dos seus parceiros. Os resultados da segunda experi��ncia sugerem que (1) as estrat��gias ego��stas eram prevalentes at�� aos 6 anos de idade, (2) as tend��ncias altru��stas emergiram at�� aos 8 anos de idade e (3) as estrat��gias de malevol��ncia come��aram a emergir a partir dos 8 anos de idade. Estes resultados complementam a literatura relativamente escassa sobre malevol��ncia e sugerem que este comportamento est�� intimamente ligado a prefer��ncias de considera����o sobre os outros, o paroquialismo e os est��gios de desenvolvimento das crian��as.************************************************************Spite is defined as an act that causes loss of payoff to an opponent at a cost to the actor. As one of the four fundamental behaviours in sociobiology, it has received far less attention than its counterparts selfishness and cooperation. It has however been established as a viable strategy in small populations when used against negatively related individuals. Because of this, spite can either i) disappear or ii) remain at equilibrium with cooperative strategies due to the willingness of spiteful individuals to pay a cost in order to punish. This thesis sets out to understand whether propensity for spiteful behaviour is inherent or if it develops with age. For that effect, two game-theoretical experiments were performed with schoolboys and schoolgirls aged 6 to 22. The first, a 2 x 2 game, was tested in two variants: 1) a prize was awarded to both players, proportional to accumulated points; 2), a prize was given to the player with most points. Each player faced the following dilemma: i) to maximise pay-off risking a lower pay-off than the opponent; or ii) not to maximise pay-off in order to cut down the opponent below their own. The second game was a dictator experiment with two choices, (A) a selfish/altruistic choice affording more payoff to the donor than B, but more to the recipient than to the donor, and (B) a spiteful choice that afforded less payoff to the donor than A, but even lower payoff to the recipient. The dilemma here was that if subjects behaved selfishly, they obtained more payoff for themselves, while at the same time increasing their opponent payoff. If they were spiteful, they would rather have more payoff than their colleague, at the cost of less for themselves. Experiments were run in schools in two different areas in Portugal (mainland and Azores) to understand whether spiteful preferences varied with age. Results in the first experiment suggested that (1) students understood the first variant as a coordination game and engaged in maximising behaviour by copying their opponent���s plays; (2) repeating students preferentially engaged in spiteful behaviour more often than maximising behaviour, with special emphasis on 14 year-olds; (3) most students engaged in reciprocal behaviour from ages 12 to 16, as they began developing higher tolerance for their opponent choices. Results for the second experiment suggested that (1) selfish strategies were prevalent until the age of 6, (2) altruistic tendencies emerged since then, and (3) spiteful strategies began being chosen more often by 8 year-olds. These results add to the relatively scarce body of literature on spite and suggest that this type of behaviour is closely tied with other-regarding preferences, parochialism and the children���s stages of development.

Process virtualization theory (PVT) and institutional theory (INT) to explain SAAS adoption

Software as a service (SaaS) is a service model in which the applications are accessible from various client devices through internet. Several studies report possible factors driving the adoption of SaaS but none have considered the perception of the SaaS features and the pressures existing in the organization���s environment. We propose an integrated research model that combines the process virtualization theory (PVT) and the institutional theory (INT). PVT seeks to explain whether SaaS processes are suitable for migration into virtual environments via an information technology-based mechanism. INT seeks to explain the effects of the institutionalized environment on the structure and actions of the organization. The research makes three contributions. First, it addresses a gap in the SaaS adoption literature by studying the internal perception of the technical features of SaaS and external coercive, normative, and mimetic pressures faced by an organization. Second, it empirically tests many of the propositions of PVT and INT in the SaaS context, thereby helping to determine how the theory operates in practice. Third, the integration of PVT and INT contributes to the information system (IS) discipline, deepening the applicability and strengths of these theories.

A conspiracy theory for clefts : the syntax and interpretation of cleft constructions

O objetivo final deste estudo �� contribuir para a discuss��o sobre qual a medida em que conceitos sem��nticos e discursivos est��o sintaticamente codificados. Mais especificamente, investiga-se se existe alguma correla����o consistente entre alguns aspetos interpretativos e sint��ticos de quatro constru����es clivadas do Portugu��s Europeu, e como se deve dar conta teoricamente destas potenciais correla����es. As clivadas consideradas s��o as clivadas can��nicas, as pseudoclivadas, as clivadas de �� que e as clivadas de SER. Sintaticamente podemos distinguir dois tipos: clivadas bioracionais (can��nicas e pseudoclivadas) e clivadas mono-oracionais (clivadas de �� que e de SER). Todas as estruturas t��m um constituinte clivado focalizado que pode constituir tanto um foco informacional como um foco contrastivo, e uma ora����o clivada que introduz uma pressuposi����o existencial. Adicionalmente, o constituinte clivado identifica exaustivamente uma posi����o vazia na ora����o clivada. Adota-se a sem��ntica alternativa para o foco (Rooth 1985), segundo a qual o foco entoacional contribui uniformemente um conjunto de alternativas na Forma L��gica. Regras pragm��ticas operando neste conjunto d��o origem a duas implicaturas que podem ser suspensas: pressuposi����o existencial e exaustividade. Dado que as clivadas de �� que e as de SER t��m a mesma interpreta����o que ora����es n��o-clivadas, conclui-se que a sua estrutura sint��tica particular n��o contribui para estas propriedades interpretativas. Em contrapartida, as clivadas bioracionais, que s��o ora����es copulativas especificacionais, t��m uma presuposi����o existencial e uma interpreta����o exaustiva que n��o pode ser suspensa, tal como as ora����es especificacionais n��o-clivadas. Argumenta-se que isto se deve ao facto de o constituinte clivado identificar uma vari��vel introduzida por uma descri����o definida. Demonstra-se que a ora����o clivada, uma relativa em posi����o de complemento de um determinador definido nas clivadas can��nicas e uma relativa livre nas pseudoclivadas, tem a mesma denota����o que um DP definido, e portanto tem uma pressuposi����o existencial inerente. A interpreta����o exaustiva deve-se �� rela����o identificacional entre o constituinte clivado e a descri����o definida. Al��m disso, defende-se que em Portugu��s Europeu um tra��o de foco n��o desencadeia movimento-A��� para um FocP especializado. Os constituintes focalizados movem-se antes por raz��es independentes do foco. Isto �� confirmado pelo facto de apenas o constituinte clivado das clivadas de �� que ter propriedades de movimento A���, os outros parecem estar in situ. Prop��e-se que o constituinte clivado das clivadas de �� que �� um t��pico com um tra��o de foco que se move para um TopP. Esta an��lise d�� conta da exist��ncia de restri����es discursivas semelhantes para t��picos n��o focalizados e para o constituinte clivado das clivadas de �� que. O tra��o quantificacional de foco arrastado pela topicaliza����o d�� origem a efeitos de interven����o, causando a n��o-recursividade do foco na periferia esquerda e a sua incompatibilidade com movimento de outros constituintes com tra��os quantificacionais. A an��lise prediz as restri����es de encaixe observadas para as clivadas de �� que. Finalmente, desenvolve-se uma an��lise sint��tica das clivadas de SER que aproxima estas estruturas das estruturas com part��culas de foco. Prop��e-se que a c��pula �� um operador sens��vel ao foco que �� merged juntamente com o constituinte clivado. As restri����es distribucionais da c��pula devem-se a requisitos selecionais de n��cleos.

Quantum field theory approach to the optical conductivity of strained and deformed graphene

The computation of the optical conductivity of strained and deformed graphene is discussed within the framework of quantum field theory in curved spaces. The analytical solutions of the Dirac equation in an arbitrary static background geometry for one dimensional periodic deformations are computed, together with the corresponding Dirac propagator. Analytical expressions are given for the optical conductivity of strained and deformed graphene associated with both intra and interbrand transitions. The special case of small deformations is discussed and the result compared to the prediction of the tight-binding model.

Pseudofermion dynamical theory for the spin dynamical correlation functions of the half-filled 1D Hubbard model

A modified version of the metallic-phase pseudofermion dynamical theory (PDT) of the 1D Hubbard model is introduced for the spin dynamical correlation functions of the half-filled 1D Hubbard model Mott��� Hubbard phase. The Mott���Hubbard insulator phase PDT is applied to the study of the model longitudinal and transverse spin dynamical structure factors at finite magnetic field h, focusing in particular on the sin- gularities at excitation energies in the vicinity of the lower thresholds. The relation of our theoretical results to both condensed-matter and ultra-cold atom systems is discussed.