Developing Libraries Using Software Transactional Memory

Software transactional memory is a promising programming model that adapts many concepts borrowed from the databases world to control concurrent accesses to main memory (RAM) locations. This paper discusses how to support apparently irreversible operations, such as memory allocation and deallocation, within software libraries that will be used in (software memory) transactional contexts, and propose a generic and elegant approach based on a handler system, which provide the means to create and execute compensation actions at key moments during the life-time of a transaction.

Potential of CPV receivers integrating screen-printed solar cells

Dissertação para obtenção do Grau de Mestre em Energias Renováveis – Conversão Eléctrica e Utilização Sustentável

On the existence of pure-strategy equilibria in large games

Over the years, several formalizations and existence results for games with a continuum of players have been given. These include those of Schmeidler (1973), Rashid (1983), Mas-Colell (1984), Khan and Sun (1999) and Podczeck (2007a). The level of generality of each of these existence results is typically regarded as a criterion to evaluate how appropriate is the corresponding formalization of large games. In contrast, we argue that such evaluation is pointless. In fact, we show that, in a precise sense, all the above existence results are equivalent. Thus, all of them are equally strong and therefore cannot rank the different formalizations of large games.

Thermal performance of cool facades: evaluation by Infrared Thermography

High reflective paints (cool paints) are used on flat roofs to reduce heat gains from the incidence of solar radiation and thus improve the thermal comfort and energy efficiency of buildings, especially in summer periods. Given the application potential of these paints on vertical surfaces, a research study has been developed to evaluate the thermal performance of reflective paints on walls under real exposure conditions. Accordingly, different reflective paints have been applied as the final coating of an ETICS type solution, on the facades of a full scale experimental cell built at LNEC campus. For being applied in an ETICS system a paint has to fulfill several requirements, whether aesthetic or functional (such as the adhesion between the coating layers or the durability of the insulation), essential for its efficient performance. Since this construction coating system is subject to a prolonged sun exposure, various problems may arise, such as paint degradation or deterioration of the thermal insulation properties, particularly when dark colors are applied. To evaluate the thermal performance of the chosen paints, the method of non-destructive analysis by Infrared Thermography was used. Thermography allows knowing the temperature distribution of facades by measuring the radiation emitted by their surfaces. To complement the thermographic diagnosis, thermocouples were placed between the insulation and the paint system of the experimental cell. Additional laboratory tests allowed the characterization of the optical properties (reflectance and emittance) of the different reflective paints used in this study. The comparative analysis of the thermal performance of reflective and conventional paints revealed that the reflective paint allows a reduction of the facade surface temperature, reducing the risk of loss of insulating properties of the ETICS system and thus ensuring its longevity and functionality. The color of the paint used affects, naturally, the reflective ability of the surface and may have an important role in energy balance of the building. This paper also showed the potential of infrared thermography in the evaluation of the thermal performance of reflective paints.

Contingencies of humble leadership

Double degree

Infraventus-internationalizing a renewables business to Kenya

Infraventus – Internationalizing a Renewables Business to Kenya Infraventus is a renewable energy development company, with a consolidated experience, since 1988, in developing, constructing and operating projects mainly in Portugal, but also in other countries: Spain, Poland, France, Australia, Finland and Panama, and is now regarding Kenya as a possible destiny. Kenya is the biggest economy of East Africa, with a growing GDP around 5% and a low level of electric grid coverage thru its territory, 33% of national access to electricity. Kenya energy policy is intended to promote the investment in renewables; wind and sun are existing resources in good measures. Kenya is an interesting destiny to Infraventus, but has many risks. The objective of this dissertation is to evaluate the possible advantages of this investment and risks and propose recommendations about how to mitigate them considering alternative entry mode

The determinants of net interest margins & net interest spreads in the Russian & Japanese Commercial Banking sectors

This study presents an empirical investigation of the determinants of net interest margins and spreads in the Russian and Japanese banking sectors with a particular focus on commercial banks. Net interest mar-gins and spreads serve as indicators of financial intermediation efficiency. This paper employed a bank-level unbalanced panel dataset prolonging from 2005 to 2014. My main empirical results show that bank characteristics explain the most of the variation in not only net interest margins but also in spreads. Capi-talization, liquidity risk, inflation, economic growth, private and government debt are important determi-nants of margin in Russia. In Japan to the contrary loan and deposit market concentration along with bank size do predominate. Common significant variables in both countries are the substitution effect, cost effi-ciency and profitability. Turning to net interest spreads, micro- and macro-specific variables are the main significant drivers in Russia. I reach the conclusion that there are no significant determinants of net interest spreads in Japan within the original selection of variables, but operating efficiency and deposits to total funding seem to prevail. In both countries, there are solid differences in the net interest margins as well as spreads once the pre- and the post-crisis periods are considered.