Integrando problem frames com aspectos

Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do grau de Mestre em Engenharia Informática

A new approach to the initial value problem

5th Portuguese Conference on Automatic Control, September, 5-7, 2002, Aveiro, Portugal

Modeling assembly program with constraints. A contribution to WCET problem

Dissertação para obtenção do Grau de Mestre em Lógica Computacional

GIS capacity building for risk management to help developing countries:Case of climate change problem in Amhara rural region (Ethiopia)

Dissertation submitted in partial fulfillment of the requirements for the Degree of Master of Science in Geospatial Technologies.

Sintomas somatoformes em Medicina Geral e Familiar

RESUMO: Os doentes que vão à consulta com sintomas físicos para os quais o médico não encontra uma causa orgânica, são frequentes na Medicina Geral e Familiar, embora não sejam específicos, e são o objecto de estudo do presente trabalho. Não deixar uma doença por diagnosticar (erro de tipo II) sem contudo rotular pessoas saudáveis como doentes (erro de tipo I) é um dos mais difíceis problemas da prática clínica diária e para o qual não existe uma orientação infalível e não é previsível que alguma vez venha a existir. Mas se o diagnóstico de doença ou não-doença é difícil, o tratamento dos que não tem doença, embora com sofrimento, também não é mais fácil, sobretudo, se estivermos conscientes do sofrimento que determina a medicalização e a iatrogenia. O presente trabalho está estruturado em 3 partes. Na primeira parte descrevemos a nossa visão integrada do que apreendemos da leitura da literatura publicada e à qual tivemos acesso. À semelhança do que se verifica na maioria das áreas da Medicina esta é também uma em que o conhecimento cresce a ritmo exponencial. No entanto, à falta de conceitos precisos e de definições consensuais sucede um conhecimento, por vezes, pouco consistente, tanto mais que estamos na fronteira entre a cultura leiga e a cultura erudita médica em que os significados devem, a todo o momento, ser validados. Fizemos uma revisão sobre as definições do que está em questão, sobre o que se sabe sobre a frequência dos sintomas físicos na população, quantos recorrem aos serviços de saúde e o que lhes é feito. Passámos por uma revisão da fisiologia destes sintomas e algumas explicações fisiopatológicas para terminarmos sobre o que os doentes pensam sobre os seus sintomas e os cuidados que recebem e o que os profissionais pensam sobre estes doentes. Esta parte termina com uma revisão das propostas de abordagem para este tipo de doentes. Na segunda parte, descrevemos os estudos empíricos focados no problema dos pacientes com sintomas físicos mas sem evidência de doença orgânica. Começa por uma apresentação dos aspectos processuais e metodológicos dos estudos realizados, mais especificamente, de dois estudos quantitativos e um qualitativo. No primeiro estudo pretendeu-se avaliar quais são os sintomas físicos e a sua frequência na população em geral e a frequência de pacientes que procuram (ou não) os serviços de saúde tendo como motivo este tipo de sintomas. O objectivo deste estudo é contribuir para a demonstração que este tipo de sintomas faz parte da vida do dia-a-dia e que, na maioria das vezes, só por si não significa doença, sem contudo negar que representa sofrimento, por vezes até maior do que quando há patologia orgânica. Se no primeiro estudo era demonstrar que os sintomas físicos são frequentes na população, no segundo estudo o objectivo é demonstrar que pacientes com este tipo de sintomas são igualmente frequentes e que o tipo de sintomas apresentados na consulta não difere dos referidos pela população em geral. Pretendia-se ainda saber o que é feito ou proposto pelo médico a estes doentes e se estes doentes traziam ou não, junto com os sintomas, ideias explicativas para os mesmos. Finalmente e não menos importante, é avaliar o grau de fidedignidade do diagnóstico de sintoma somatoforme, chamando assim ao sintoma físico que foi “levado” à consulta e que o médico diagnosticou como não tendo causa orgânica. O terceiro estudo parte do conhecimento adquirido que a Medicina tem muitas respostas para este problema, mas poucas que se possam considerar satisfatórias se usadas isoladamente. Que a maioria das soluções é procurada entre a cultura médica e num paradigma reducionista de separação mente-corpo. Contudo, se o sintoma é “construído” pelo doente, se o principal problema não está no sintoma mas na forma como o paciente o vê, então pareceu-nos lógico que a solução também tem que passar por integrarmos no plano de abordagem o que o doente entende ser melhor para si. Nesta sequência, entrevistaram-se alguns doentes cujo diagnóstico de sintomas somatoformes estava demonstrado pelo teste do tempo. Por isso, entrevistaram-se doentes que já tinham ido à consulta de MGF há mais de 6 meses por sintomas somatoformes e, na data da entrevista, o diagnóstico se mantinha inalterado, independentemente da sua evolução. As entrevistas visaram conhecer as ideias dos doentes sobre o que as motivou a procurarem a consulta, o que pensavam da forma como foram cuidados e que ideias tinham sobre o que os profissionais de saúde devem fazer para os ajudar a restabelecer o equilíbrio com o seu ambiente evitando a medicalização, a iatrogenia e a evolução para a cronicidade. Na terceira parte, discutem-se e integram-se os resultados encontrados no conhecimento previamente existente. Tenta-se teorizar, fazer doutrina sobre o tema e contribuir para abordagens terapêuticas mais personalizadas, abrangentes, variadas e multimodais, baseadas sempre no método clínico centrado no paciente, ou de modo menos correcto mas enfático, baseadas no método centrado na relação. Apresentam-se algumas hipóteses de trabalhos futuros sobre o tema e, sobretudo, esperamos ter contribuído para o reconhecimento da necessidade de a comunicação médico-doente ser uma aprendizagem transversal a todos os profissionais de saúde e ao longo da vida, com a ideia que é sempre possível fazer melhor, caso contrário tenderemos, inexoravelmente, a fazer cada vez pior.-----------ABSTRACT: Patients who go to consultation with physical symptoms, for which the doctor does not find an organic cause, are the subject of the present study. They are common in family medicine, although not specific. Do not let an undiagnosed disease (type II error), but without labeling healthy people as patients with disease (type I error) is one of the most difficult problems in clinical practice and for which doesn’t exist an infallible guide and it is unlikely that any since coming into existence. But, if the diagnosis of disease or non-disease is difficult, the treatment of those who do not have the disease, though suffering, it is not easy, especially if we are aware of the suffering that medicalization and iatrogenic determines. This work is structured in three parts. In the first part we describe our integrated view of what we grasp from reading the published literature and to which we had access. Similar to that found in most areas of medicine, this is also one in which knowledge grows exponentially. However, the absence of precise concepts and consensual definitions determines an inconsistent knowledge, especially because we're on the border between secular culture and medical culture where, at all times, the meaning must be validated. We did a review on the definitions of what is at issue, what is known about the frequency of physical symptoms in the population, how many use the services of health and what they receive as care. We went through a review of the physiology of these symptoms and some pathophysiological explanations, to finish on what patients think about their symptoms and how they perceived the care they received and, finally, what professionals think about these patients. This part ends with a review of the approaches proposed for such patients. In the second part, we describe the empirical studies focused on the problem of patients with physical symptoms but no evidence of organic disease. Begins with a presentation of the procedural and methodological aspects of studies, more specifically, two quantitative and one qualitative. The first study sought to assess which are the physical symptoms, their incidence in the general population and the frequency they seek (or not) health services on behalf of those symptoms. The aim behind this study was to contribute to the demonstration that this type of symptoms is part of life's day-to-day and that, in most cases, does not represent disease by itself, without denying that they represent suffering, sometimes even greater than when there are organic disease. The first study endeavor to demonstrate that the physical symptoms are common in the population. The second study aspires to demonstrate that patients with such symptoms are also common and that the type of symptoms presented in the consultation does not differ from those in the general population. The aim was also to know what is done or proposed by the physician for these patients and if these patients brought or not, along with the symptoms, explanatory ideas for them. Finally and not least, it would try to assess the degree of reliability of diagnosis of somatoform symptoms, thus drawing the physical symptom that patient presents in the consultation and that the doctor diagnosed as having no organic cause. The third study starts from the acquired knowledge that medicine has many answers to this problem, but few can be considered satisfactory if used in isolation. The most solutions are sought in the medical culture and based on a reductionist paradigm of mind-body. However, if the symptom is "built" by the patient, if the main problem is not the symptom but the way the patient sees it, then it seemed logical to us that the solution must integrate the approaches that patients believes are best for them. Subsequently, a few patients, whose diagnosis of somatoform symptoms was demonstrated by the test of time, were interviewed. Therefore, patients who were interviewed had gone to the consultation of family medicine more than 6 months before for somatoform symptoms and. at the moment of the interview, the diagnosis remained unchanged, regardless of their evolution. The interviews aimed to ascertain the patients' ideas about what motivated them to seek consultation, what they thought about the care they got and which ideas they have about what health professionals should do to help these patients to re-establish equilibrium with its environment avoiding medicalization, iatrogenic effects and the evolution to chronicity. In the third section, we discuss and integrate the results found in previously existing knowledge. Attempts to theorize on the subject and contribute to more personalized treatment, comprehensive, varied and multi-modal approaches, always based on patient-centered clinical method, with emphasis on the relationship. We presents some hypotheses for future work on the subject and,above all, defend the recognition of the importance of lifelong learning communication skills for all health professionals, with the idea that we can always do better, otherwise we tend inexorably to do worse.

Collateral, default penalties and infinite horizon equilibrium

Pascoa and Seghir (2009) noticed that when collateralized promises become subject to utility penalties on default, Ponzi schemes may occur. However, equilibrium exists in some interesting cases. Under low penalties, equilibrium exists if the collateral does not yield utility (for example, when it is a productive asset or a security). Equilibrium exists also under more severe penalties and collateral utility gains, when the promise or the collateral are nominal assets and the margin requirements are endogenous: relative inflation rates and margin coefficients can make the income effects dominate the penalty effects. An equilibrium refinement avoids no-trade equilibria with unduly repayment beliefs. Our refinement differs from the one used by Dubey, Geanakoplos and Shubik (2005) as it does not eliminate no trade equilibria whose low delivery rates are consistent with the propensity to default of agents that are on the verge of selling.

Business model analysis of Mobitto: How to solve the chicken and egg problem of a multi-sided platform?

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

Corporate finance in general equilibrium models with incomplete markets: A survey

A Masters Thesis, presented as part of the requirements for the award of a Research Masters Degree in Economics from 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

Experimental Gravimetric Adsorption Equilibrium of n-Alkanes and Alkenes, Carbon Dioxide and Nitrogen in MIL-53(Al) and Zeolite 5A

Dissertação para obtenção do Grau de Mestre em Engenharia Química e Bioquímica

Upgrade of an experimental volumetric unit for gas adsorption equilibrium studies

In this work, a volumetric unit previously assembled by the research group was upgraded. This unit revamping was necessary due to the malfunction of the solenoid valves employed in the original experimental setup, which were not sealing the gas properly leading to erroneous adsorption equilibrium measurements. Therefore, the solenoid valves were substituted by manual ball valves. After the volumetric unit improvement its operation was validated. For this purpose, the adsorption equilibrium of carbon dioxide (CO2) at 323K and 0 - 20 bar was measured on two different activated carbon samples, in the of extrudates (ANG6) and of a honeycomb monolith (ACHM). The adsorption equilibrium results were compared with data previously measured by the research group, using a high-pressure microbalance from Rubotherm GmbH (Germany) – gravimetric. The results obtained using both apparatuses are coincident thus validating the good operation of the volumetric unit upgraded in this work. Furthermore, the adsorption equilibrium of CO2 at 303K and 0 - 10 bar on Metal-Organic Frameworks (MOFs) Cu-BTC and Fe-BTC was also studied. The CO2 adsorption equilibrium results for both MOFs were compared with the literature results showing good agreement, which confirms the good quality of the experimental results obtained in the new volumetric unit. Cu-BTC sample showed significantly higher CO2 adsorption capacity when compared with the Fe-BTC sample. The revamping of the volumetric unit included a new valve configuration in order to allow testing an alternative method for the measurement of adsorption equilibrium. This new method was employed to measure the adsorption equilibrium of CO2 on ANG6 and ACHM at 303, 323 and 353K within 0-10 bar. The good quality of the obtained experimental data was testified by comparison with data previously obtained by the research group in a gravimetric apparatus.

Essays on bounded rationality: Individual decision and strategic interaction

Economics is a social science which, therefore, focuses on people and on the decisions they make, be it in an individual context, or in group situations. It studies human choices, in face of needs to be fulfilled, and a limited amount of resources to fulfill them. For a long time, there was a convergence between the normative and positive views of human behavior, in that the ideal and predicted decisions of agents in economic models were entangled in one single concept. That is, it was assumed that the best that could be done in each situation was exactly the choice that would prevail. Or, at least, that the facts that economics needed to explain could be understood in the light of models in which individual agents act as if they are able to make ideal decisions. However, in the last decades, the complexity of the environment in which economic decisions are made and the limits on the ability of agents to deal with it have been recognized, and incorporated into models of decision making in what came to be known as the bounded rationality paradigm. This was triggered by the incapacity of the unboundedly rationality paradigm to explain observed phenomena and behavior. This thesis contributes to the literature in three different ways. Chapter 1 is a survey on bounded rationality, which gathers and organizes the contributions to the field since Simon (1955) first recognized the necessity to account for the limits on human rationality. The focus of the survey is on theoretical work rather than the experimental literature which presents evidence of actual behavior that differs from what classic rationality predicts. The general framework is as follows. Given a set of exogenous variables, the economic agent needs to choose an element from the choice set that is avail- able to him, in order to optimize the expected value of an objective function (assuming his preferences are representable by such a function). If this problem is too complex for the agent to deal with, one or more of its elements is simplified. Each bounded rationality theory is categorized according to the most relevant element it simplifes. Chapter 2 proposes a novel theory of bounded rationality. Much in the same fashion as Conlisk (1980) and Gabaix (2014), we assume that thinking is costly in the sense that agents have to pay a cost for performing mental operations. In our model, if they choose not to think, such cost is avoided, but they are left with a single alternative, labeled the default choice. We exemplify the idea with a very simple model of consumer choice and identify the concept of isofin curves, i.e., sets of default choices which generate the same utility net of thinking cost. Then, we apply the idea to a linear symmetric Cournot duopoly, in which the default choice can be interpreted as the most natural quantity to be produced in the market. We find that, as the thinking cost increases, the number of firms thinking in equilibrium decreases. More interestingly, for intermediate levels of thinking cost, an equilibrium in which one of the firms chooses the default quantity and the other best responds to it exists, generating asymmetric choices in a symmetric model. Our model is able to explain well-known regularities identified in the Cournot experimental literature, such as the adoption of different strategies by players (Huck et al. , 1999), the inter temporal rigidity of choices (Bosch-Dom enech & Vriend, 2003) and the dispersion of quantities in the context of di cult decision making (Bosch-Dom enech & Vriend, 2003). Chapter 3 applies a model of bounded rationality in a game-theoretic set- ting to the well-known turnout paradox in large elections, pivotal probabilities vanish very quickly and no one should vote, in sharp contrast with the ob- served high levels of turnout. Inspired by the concept of rhizomatic thinking, introduced by Bravo-Furtado & Côrte-Real (2009a), we assume that each per- son is self-delusional in the sense that, when making a decision, she believes that a fraction of the people who support the same party decides alike, even if no communication is established between them. This kind of belief simplifies the decision of the agent, as it reduces the number of players he believes to be playing against { it is thus a bounded rationality approach. Studying a two-party first-past-the-post election with a continuum of self-delusional agents, we show that the turnout rate is positive in all the possible equilibria, and that it can be as high as 100%. The game displays multiple equilibria, at least one of which entails a victory of the bigger party. The smaller one may also win, provided its relative size is not too small; more self-delusional voters in the minority party decreases this threshold size. Our model is able to explain some empirical facts, such as the possibility that a close election leads to low turnout (Geys, 2006), a lower margin of victory when turnout is higher (Geys, 2006) and high turnout rates favoring the minority (Bernhagen & Marsh, 1997).

A public transport bus assignment problem: parallel metaheuristics assessment

Combinatorial Optimization Problems occur in a wide variety of contexts and generally are NP-hard problems. At a corporate level solving this problems is of great importance since they contribute to the optimization of operational costs. In this thesis we propose to solve the Public Transport Bus Assignment problem considering an heterogeneous fleet and line exchanges, a variant of the Multi-Depot Vehicle Scheduling Problem in which additional constraints are enforced to model a real life scenario. The number of constraints involved and the large number of variables makes impracticable solving to optimality using complete search techniques. Therefore, we explore metaheuristics, that sacrifice optimality to produce solutions in feasible time. More concretely, we focus on the development of algorithms based on a sophisticated metaheuristic, Ant-Colony Optimization (ACO), which is based on a stochastic learning mechanism. For complex problems with a considerable number of constraints, sophisticated metaheuristics may fail to produce quality solutions in a reasonable amount of time. Thus, we developed parallel shared-memory (SM) synchronous ACO algorithms, however, synchronism originates the straggler problem. Therefore, we proposed three SM asynchronous algorithms that break the original algorithm semantics and differ on the degree of concurrency allowed while manipulating the learned information. Our results show that our sequential ACO algorithms produced better solutions than a Restarts metaheuristic, the ACO algorithms were able to learn and better solutions were achieved by increasing the amount of cooperation (number of search agents). Regarding parallel algorithms, our asynchronous ACO algorithms outperformed synchronous ones in terms of speedup and solution quality, achieving speedups of 17.6x. The cooperation scheme imposed by asynchronism also achieved a better learning rate than the original one.

On the labor share the long-run equilibrium and its adjustment process

This research computes an Equilibrium Labor Share using a VECM for a panel of 19 countries, analyzes what determines the speed at which the labor share adjusts towards that equilibrium and decomposes this adjustment in terms of real wages and employment. Results suggest that the speed at which a country adjusts decreases with employment protection legislation and labor taxes. Most countries’ labor shares adjustment is made through real wages changes instead of changing employment, suggesting that wage moderation policies may play an important role on the adjustment process without harming employment. Keywords: Equilibrium

On the labor share the long-run equilibrium and its adjustment process

This research computes an Equilibrium Labor Share using a VECM for a panel of 19 countries, analyzes what determines the speed at which the labor share adjusts towards that equilibrium and decomposes this adjustment in terms of real wages and employment. Results suggest that the speed at which a country adjusts decreases with employment protection legislation and labor taxes. Most countries’ labor shares adjustment is made through real wages changes instead of changing employment, suggesting that wage moderation policies may play an important role on the adjustment process without harming employment.