Generalized Dasymetric Mapping Algorithm for Accessing Land-Use Change

Contém resumo

Control in distribution networks with demand side management

The way in which electricity networks operate is going through a period of significant change. Renewable generation technologies are having a growing presence and increasing penetrations of generation that are being connected at distribution level. Unfortunately, a renewable energy source is most of the time intermittent and needs to be forecasted. Current trends in Smart grids foresee the accommodation of a variety of distributed generation sources including intermittent renewable sources. It is also expected that smart grids will include demand management resources, widespread communications and control technologies required to use demand response are needed to help the maintenance in supply-demand balance in electricity systems. Consequently, smart household appliances with controllable loads will be likely a common presence in our homes. Thus, new control techniques are requested to manage the loads and achieve all the potential energy present in intermittent energy sources. This thesis is focused on the development of a demand side management control method in a distributed network, aiming the creation of greater flexibility in demand and better ease the integration of renewable technologies. In particular, this work presents a novel multi-agent model-based predictive control method to manage distributed energy systems from the demand side, in presence of limited energy sources with fluctuating output and with energy storage in house-hold or car batteries. Specifically, here is presented a solution for thermal comfort which manages a limited shared energy resource via a demand side management perspective, using an integrated approach which also involves a power price auction and an appliance loads allocation scheme. The control is applied individually to a set of Thermal Control Areas, demand units, where the objective is to minimize the energy usage and not exceed the limited and shared energy resource, while simultaneously indoor temperatures are maintained within a comfort frame. Thermal Control Areas are overall thermodynamically connected in the distributed environment and also coupled by energy related constraints. The energy split is performed based on a fixed sequential order established from a previous completed auction wherein the bids are made by each Thermal Control Area, acting as demand side management agents, based on the daily energy price. The developed solutions are explained with algorithms and are applied to different scenarios, being the results explanatory of the benefits of the proposed approaches.

Measuring the effects of price movements on private consumption

This paper studies how shocks in the prices of Food, Energy and Financial Assets affect private consumption using a VAR Model. Then, the total effects are broken into direct and indirect effects, using the coefficients taken from the previous model. We use quarterly data for the Portuguese economy from the last 20 years. We found that energy prices and financial assets have a strong connection with consumption, suggesting that the economy may be too exposed to shocks in these markets.

A wave of change: Labor market and social security impacts of the EU refugee inflow

The recent massive inflow of refugees to the European Union (EU) raises a number of unanswered questions on the economic impact of this phenomenon. To examine these questions, we constructed an overlapping-generations model that describes the evolution of the skill premium and of the welfare benefit level in relevant European countries, in the aftermath of an inflow of asylum-seekers. In our simulation, relative wages of skilled workers increase between 8% and 11% in the period of the inflow; their subsequent time path is dependent on the initial skill premium. The entry of migrants creates a fiscal surplus of about 8%, which can finance higher welfare benefits in the subsequent periods. These effects are weaker in a scenario where refugees do not fully integrate into the labor market.

The price of honour: The corporate governance of Banco Espirito Santo

The Price of Honour is a case study, supported with teaching notes, which describes the events and circumstances surrounding the implosion of one of Portugal’s most systemically important banks - Banco Espírito Santo (BES). The case focuses on BES’s corporate governance and how the Espírito Santo family’s tight control of the bank led to its exploitation. Although the situation caught the attention of the bank’s supervisors, their untimely actions could not prevent BES’s financial health from crumbling only two months after a rights issue. With little leeway, the supervisors put forward a resolution which dramatically ended the bank’s centennial legacy.

Contratos de prestação de serviços de comunicações electrónicas

The object of this dissertation is the analysis of the legal framework applicable to contracts for provision of electronic communications services, while trying to offer solutions to some of the issues regarding this matter. The main focus of this study will be the rules concerning service’s suspension, which have been recently amended. The technological development and the establishment of these services as information transmitters and work tools were noteworthy for its growing importance at the present time. These services include cable television, telephone (landline and mobile) and internet and they are regulated by Law nr 23/96, July 26th, along with other essential public services. Said law sets a group of principles and duties, such as good faith (article 3), continuity and quality of the service (article 7) and the duty to rightfully inform the user (article 4), in order to protect the users. For the analysis of legal framework applicable to these particular contracts it is also fundamental to mention Law nr 5/2004, February 10th, known as Electronic Communications Law. The provisions regarding the service’s suspension are currently prescribed in articles 52.º and 52.º-A of the law. Given the amendments introduced by Law nr 10/2013, January 28th, consumers are subjected to a regulation different from the one applicable to the other users, established in the new article 52.º-A. From our analysis, we have concluded that the main change from past provisions has to do with the automatic termination of the contract as consequence of the consumer’s failure to pay the price or to conclude a written payment arrangement after service’s suspension.

Exchange rate pressure in Angola

The objective of this work is to develop an operational tool to analyze exchange rate pressure in the context of Angola. The Angolan economy exhibits a number of relevant characteristics: a closed financial account, a partially controlled current account, a highly dollarized economy and exports (oil) price determined in World markets. These features have a direct effect on the demand of foreign currency and motivate their inclusion in the specification of a model for Angola. The model provides the rational for a measure of an exchange market rate pressure (EMP) index that contains exports changes, imports changes, the foreign interest rate and inflation and the change in foreign reserves corrected for a measure dollarization. The empirical performance new measure is comparable (slightly better) to the performance of the EMP indexes obtained in Eichengreen Rose and Wyplosz (1994) and Klassen and Jager (2011).

The effects of cultural heritage on residential property values: Evidence from Lisbon, Portugal

This paper examines the impact of historic amenities on residential housing prices in the city of Lisbon, Portugal. Our study is directed towards identifying the spatial variation of amenity values for churches, palaces, lithic (stone) architecture and other historic amenities via the housing market, making use of both global and local spatial hedonic models. Our empirical evidence reveals that different types of historic and landmark amenities provide different housing premiums. While having a local non-landmark church within 100 meters increases housing prices by approximately 4.2%, higher concentrations of non-landmark churches within 1000 meters yield negative effects in the order of 0.1% of prices with landmark churches having a greater negative impact around 3.4%. In contrast, higher concentration of both landmark and non-landmark lithic structures positively influence housing prices in the order of 2.9% and 0.7% respectively. Global estimates indicate a negative effect of protected zones, however this significance is lost when accounting for heterogeneity within these areas. We see that the designation of historic zones may counteract negative effects on property values of nearby neglected buildings in historic neighborhoods by setting additional regulations ensuring that dilapidated buildings do not damage the city’s beauty or erode its historic heritage. Further, our results from a geographically weighted regression specification indicate the presence of spatial non-stationarity in the effects of different historic amenities across the city of Lisbon with variation between historic and more modern areas.

Empowerment and intentions to resist future change: the moderating effect organization-based self-esteem

Nowadays, organizations face a constant need for adaptability, increasing the importance of change management. Our study focuses of how empowering leadership influences intentions to resist future changes, mediated by the effects of psychological and structural empowerment. From the responses of the two questionnaires (N1=230; Ntf=113), we found that empowering leadership fosters psychological and structural empowerment. Structural empowerment was the main driver in reducing intentions to resist future change when an employee has high organization-based self-esteem. Our findings add to the literature by examining how we can anticipate and manage change under an empowering context, building on social exchange and uncertainty reduction theories

Contributions towards smart cities : exploring block level census data for the characterization of change in Lisbon

The interest in using information to improve the quality of living in large urban areas and its governance efficiency has been around for decades. Nevertheless, the improvements in Information and Communications Technology has sparked a new dynamic in academic research, usually under the umbrella term of Smart Cities. This concept of Smart City can probably be translated, in a simplified version, into cities that are lived, managed and developed in an information-saturated environment. While it makes perfect sense and we can easily foresee the benefits of such a concept, presently there are still several significant challenges that need to be tackled before we can materialize this vision. In this work we aim at providing a small contribution in this direction, which maximizes the relevancy of the available information resources. One of the most detailed and geographically relevant information resource available, for the study of cities, is the census, more specifically the data available at block level (Subsecção Estatística). In this work, we use Self-Organizing Maps (SOM) and the variant Geo-SOM to explore the block level data from the Portuguese census of Lisbon city, for the years of 2001 and 2011. We focus on gauging change, proposing ways that allow the comparison of the two time periods, which have two different underlying geographical bases. We proceed with the analysis of the data using different SOM variants, aiming at producing a two-fold portrait: one, of the evolution of Lisbon during the first decade of the XXI century, another, of how the census dataset and SOM’s can be used to produce an informational framework for the study of cities.

Sustainable mortars with incorporation of microencapsulated phase change materials

The construction industry is responsible for high energy and raw materials consumption. Thus, it is important to minimize the high energy consumption by taking advantage of renewable energy sources and reusing industrial waste, decreasing the extraction of natural materials. The mortars with incorporation of phase change materials (PCM) have the ability to regulate the temperature inside buildings, contributing to the thermal comfort and reduction of the use of heating and cooling equipment, using only the energy supplied by the sun. The simultaneous incorporation of PCM and fly ash (FA) can reduce the energy consumption and the amount of materials landfilled. However, the addition of these materials in mortars modifies its characteristics. The main purpose of this study was the production and characterization in the fresh and hardened state of mortars with incorporation of different contents of PCM and FA. The binders studied were aerial lime, hydraulic lime, gypsum and cement. The proportion of PCM studied was 0%, 20%, 40% and 60% of the mass of the sand. The content of fly ash added to the mortars was 0%, 20%, 40% and 60% of the mass of the binder. It was possible to observe that the incorporation of PCM and fly ash in mortars caused differences in properties such as workability, microstructure, water absorption, compressive strength, flexural strength and adhesion.

Assessing the feasibility of impregnating phase change materials in lightweight aggregate for development of thermal energy storage systems

This paper assesses the feasibility of impregnation/encasement of phase change materials (PCMs) in lightweight aggregates (LWAs). An impregnation process was adopted to carry out the encasement study of two different PCMs in four different LWAs. The leakage of the impregnated/encased PCMs was studied when they were submitted to freeze/thawing and oven drying tests, separately. The results confirmed that, the impregnation/encasement method is effective with respect to the large thermal energy storage density, and can be suitable for applications were PCMs cannot be incorporated directly such as asphalt road pavements.

Equity offerings, stock price crash risk, and the impact of securities regulation: international evidence

We examine whether earnings manipulation around seasoned equity offerings (SEOs) is associated with an increase in the likelihood of a stock price crash post-issue and test whether the enactment of securities regulations attenuate the relation between SEOs and crash risk. Empirical evidence documents that managerial tendency to conceal bad news increases the likelihood of a stock price crash (Jin and Myers, 2006; Hutton, Marcus, and Tehranian, 2009). We test this hypothesis using a sample of firms from 29 EU countries that enacted the Market Abuse Directive (MAD). Consistent with our hypothesis, we find that equity issuers that engage in earnings management experience a significant increase in crash risk post-SEO relative to control groups of non-issuers; this effect is stronger for equity issuers with poor information environments. In addition, our findings show a significant decline in crash risk post-issue after the enactment of MAD that is stronger for firms that actively manage earnings. This decline in post-issue crash risk is more effective in countries with high ex-ante institutional quality and enforcement. These results suggest that the implementation of MAD helps to mitigate managers’ ability to manipulate earnings around SEOs.

Earnings management and stock price crashes post-crossdelisting

We test whether cross-delisted firms from the major U.S. stock exchanges experience an increase in crash risk associated with earnings management. Consistent with our prediction, we find that earnings management have a greater positive impact on stock price crash risk post-cross-delisting when compared to a sample of still cross-listed firms. Moreover, our results suggest that this effect is more pronounced for crossdelisted firms from countries with weaker investor protection and poorer quality of their information environment. We further examine whether managers’ ability to manipulate earnings increases post-cross-delisting around seasoned equity offerings. Our evidence shows that cross-delisted firms that engage in earnings management to inflate reported earnings prior to a seasoned equity offering are more likely to observe a subsequent stock price crash.