Preventing atomicity violations with contracts

Concurrent programming is a difficult and error-prone task because the programmer must reason about multiple threads of execution and their possible interleavings. A concurrent program must synchronize the concurrent accesses to shared memory regions, but this is not enough to prevent all anomalies that can arise in a concurrent setting. The programmer can misidentify the scope of the regions of code that need to be atomic, resulting in atomicity violations and failing to ensure the correct behavior of the program. Executing a sequence of atomic operations may lead to incorrect results when these operations are co-related. In this case, the programmer may be required to enforce the sequential execution of those operations as a whole to avoid atomicity violations. This situation is specially common when the developer makes use of services from third-party packages or modules. This thesis proposes a methodology, based on the design by contract methodology, to specify which sequences of operations must be executed atomically. We developed an analysis that statically verifies that a client of a module is respecting its contract, allowing the programmer to identify the source of possible atomicity violations.

Functional monolithic platforms for antibody purification

Dissertação para obtenção do Grau de Doutor em Química Sustentável

The politics of growth: Can lobbying raise growth and welfare?

This paper aims at analyzing the effects of lobbying over economic growth and primarily welfare. We model explicitly the interaction between policy-makers and firms in a setup where the latter undertakes political contributions to the former in exchange for more restrictive market regulations which induce exit and enhance the profitability of the market. In a sectorial equilibrium, despite stimulating growth, lobbying restricts the market structure and reduces welfare when compared to the free-entry outcome. However, once general equilibrium considerations are taken into account, we find that lobbying may improve welfare over a welfare maximizing free-entry equilibrium, by means of an expansion in aggregate demand. This introduces a new paradigm in the literature about the effects of lobbying over economic performance.

R&D spillovers in an endogenous growth model with physical capital, human capital and varieties

There is a family of models with Physical, Human capital and R&D for which convergence properties have been discussed (Arnold, 2000a; Gómez, 2005). However, spillovers in R&D have been ignored in this context. We introduce spillovers in this model and derive its steady-state and stability properties. This new feature implies that the model is characterized by a system of four differential equations. A unique Balanced Growth Path along with a two dimensional stable manifold are obtained under simple and reasonable conditions. Transition is oscillatory toward the steady-state for plausible values of parameters.

Endogenous spillovers in the trade-off between centralization and decentralization

In this paper, we revisit the classical trade-off between centralized and decentralized provision of local public goods, in a setting where interregional spillovers depend on the level of a national public good. We compare the standard benevolent planner approach with a political economy in which decisions, in a centralized system, are undertaken by a non-cooperative legislature with no separation of powers. We observe that the policy-maker in a centralized system is able to play both with local public goods and spillovers, a mechanism that is not available under a decentralized system. When compared to the traditional exogenous spillovers assumption, this improves the case for centralization under the standard benevolent planner approach. However, the same is not necessarily true in the non-cooperative legislature, as in this case the interests of the legislator do not need to be aligned with those of the society. Finally, we extend the traditional political economy analysis by considering a legislature in which decisions are undertaken by different committees (separation of powers), and show that it performs better than the original non-cooperative legislature, greatly improving the case for centralization.

Share the fame or share the blame? The reputational implications of partnerships

We use an adverse selection model to study the dynamics of firms' reputations when firms implement joint projects. We show that in contrast with projects implemented by a single firm, in the case of joint projects a firm's reputation does not necessarily increase following a success and does not necessarily decrease following a failure. We also study how reputation considerations affect firms ' decisions to participate in joint projects. We show that a high quality partner may not be preferable to a low quality partner, and that a high reputation partner is not necessarily preferable to a low reputation partner.

A Evolução dos Transportes e Acessibilidades e as Transformações na Organização do Território

O Livro consubstancia o resultado do Projecto de Carácter Exploratório "A evolução dos transportes e acessibilidades e as transformações na organização do território”, o qual visou aprofundar o conhecimento sobre os impactes territoriais dos investimentos em infra-estruturas de transporte através da análise da evolução das acessibilidades em Portugal Continental desde a década de 1980 e das suas repercussões em matéria de organização e estruturação do território, com recurso a análises de natureza quantitativa e qualitativa. O Livro encontra-se estruturado em cinco grandes capítulos. O primeiro capítulo, de natureza introdutória, procura elucidar sobre a oportunidade e relevância do projecto, assim como apresentar os objectivos que lhe estão subjacentes. Relativamente ao quadro metodológico adoptado, esta matéria encontra enquadramento no segundo capítulo. No terceiro capítulo, procede-se à revisão da literatura sobre o conceito de acessibilidade, assim como à discussão de um conjunto de indicadores de acessibilidade. O quarto capítulo centra-se na análise de informação quantitativa, mostrando a evolução das redes rodoviária e ferroviária e as melhorias registadas através da análise dos indicadores de acessibilidades. A discussão e considerações finais constam do quinto capítulo.

Transitional dynamics of an endogenous growth model with an erosion effect

The convergence features of an Endogenous Growth model with Physical capital, Human Capital and R&D have been studied. We add an erosion effect (supported by empirical evidence) to this model, and fully characterize its convergence properties. The dynamics is described by a fourth-order system of differential equations. We show that the model converges along a one-dimensional stable manifold and that its equilibrium is saddle-path stable. We also argue that one of the implications of considering this “erosion effect” is the increase in the adherence of the model to data.

InStory – The Making of na Interactive Digital Narrative

Em cooperação com Glorianna Davenport do M.I.T. Media Lab

Documenting InStory – Mobile Storytelling in a Cultural Heritage Environment

This paper describes the process and problems that had to be faced during the elaboration of a digital interactive narrative for the Instory project (http://img.di.fct.unl.pt/InStory/) implanted in «Quinta da Regaleira», Sintra, Portugal, and classified as World Heritage by Unesco. It also explores some of the practical and theoretical issues in what regards the literary terminology and strategies involved.

Avaliação de desempenho ambiental no sector público: estudo do sector da defesa

Dissertação apresentada para obtenção do Grau de Doutor em Engenharia do Ambiente pela Universidade Nova de Lisboa, Faculdade de Ciências e Tecnologia

Valorisation of vegetable oil deodorizer distillate by enzymatic reaction and membrane processing

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

Indicadores de qualidade do emprego. Uma aplicação a Portugal no contexto da União Europeia

O presente artigo decorre da investigação conducente à realização da tese de Doutoramento em Economia da autora, pelo que um agradecimento especial é dirigido ao seu orientador, o Doutor Nuno Crespo (Instituto Universitário de Lisboa, ISCTE-IUL e BRU-IUL) e à Professora Nádia Simões (Instituto Universitário de Lisboa, ISCTE-IUL e BRU-IUL). Uma versão prévia do artigo foi apresentada no Colóquio Internacional Law and Inequalities, do CES-FEUC, Universidade de Coimbra, Abril 23-24, 2012. A autora gostaria de agradecer os comentários e sugestões dos participantes na conferência.

Joga outra vez: um conjunto de objectos que nos contam histórias inteligentes

Dissertação de mestrado em Audiovisuais e Media Interactivos (Ciências da Comunicação)

Optimização do factor de cobertura de condensadores de tântalo produzidos com pós de elevada carga específica

Dissertação para obtenção do Grau de Doutor em Nanotecnologias e Nanociências