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.

Medium access control design for distributed opportunistic radio networks

Existing wireless networks are characterized by a fixed spectrum assignment policy. However, the scarcity of available spectrum and its inefficient usage demands for a new communication paradigm to exploit the existing spectrum opportunistically. Future Cognitive Radio (CR) devices should be able to sense unoccupied spectrum and will allow the deployment of real opportunistic networks. Still, traditional Physical (PHY) and Medium Access Control (MAC) protocols are not suitable for this new type of networks because they are optimized to operate over fixed assigned frequency bands. Therefore, novel PHY-MAC cross-layer protocols should be developed to cope with the specific features of opportunistic networks. This thesis is mainly focused on the design and evaluation of MAC protocols for Decentralized Cognitive Radio Networks (DCRNs). It starts with a characterization of the spectrum sensing framework based on the Energy-Based Sensing (EBS) technique considering multiple scenarios. Then, guided by the sensing results obtained by the aforementioned technique, we present two novel decentralized CR MAC schemes: the first one designed to operate in single-channel scenarios and the second one to be used in multichannel scenarios. Analytical models for the network goodput, packet service time and individual transmission probability are derived and used to compute the performance of both protocols. Simulation results assess the accuracy of the analytical models as well as the benefits of the proposed CR MAC schemes.

A systematic methodology to analyse the performance and design configurations of business interoperability in cooperative industrial networks

This thesis proposes a methodology for modelling business interoperability in a context of cooperative industrial networks. The purpose is to develop a methodology that enables the design of cooperative industrial network platforms that are able to deliver business interoperability and the analysis of its impact on the performance of these platforms. To achieve the proposed objective, two modelling tools have been employed: the Axiomatic Design Theory for the design of interoperable platforms; and Agent-Based Simulation for the analysis of the impact of business interoperability. The sequence of the application of the two modelling tools depends on the scenario under analysis, i.e. whether the cooperative industrial network platform exists or not. If the cooperative industrial network platform does not exist, the methodology suggests first the application of the Axiomatic Design Theory to design different configurations of interoperable cooperative industrial network platforms, and then the use of Agent-Based Simulation to analyse or predict the business interoperability and operational performance of the designed configurations. Otherwise, one should start by analysing the performance of the existing platform and based on the achieved results, decide whether it is necessary to redesign it or not. If the redesign is needed, simulation is once again used to predict the performance of the redesigned platform. To explain how those two modelling tools can be applied in practice, a theoretical modelling framework, a theoretical Axiomatic Design model and a theoretical Agent-Based Simulation model are proposed. To demonstrate the applicability of the proposed methodology and/or to validate the proposed theoretical models, a case study regarding a Portuguese Reverse Logistics cooperative network (Valorpneu network) and a case study regarding a Portuguese construction project (Dam Baixo Sabor network) are presented. The findings of the application of the proposed methodology to these two case studies suggest that indeed the Axiomatic Design Theory can effectively contribute in the design of interoperable cooperative industrial network platforms and that Agent-Based Simulation provides an effective set of tools for analysing the impact of business interoperability on the performance of those platforms. However, these conclusions cannot be generalised as only two case studies have been carried out. In terms of relevance to theory, this is the first time that the network effect is addressed in the analysis of the impact of business interoperability on the performance of networked companies and also the first time that a holistic approach is proposed to design interoperable cooperative industrial network platforms. Regarding the practical implications, the proposed methodology is intended to provide industrial managers a management tool that can guide them easily, and in practical and systematic way, in the design of configurations of interoperable cooperative industrial network platforms and/or in the analysis of the impact of business interoperability on the performance of their companies and the networks where their companies operate.

Migrant networks and migrant intentions to return

Social ties are potentially an important determinant of migrants’ intention to return to their home country, and yet this topic has not been addressed in the existing economics literature on international migration. This study examines the absolute and relative importance of migrant social networks both at destination and at origin. We base our research on experimental data from Batista and Narciso (2013)1. By defining networks according to different characteristics of their members and migrant return intentions with respect to three different time horizons, we are able to dissect the network effect into its components. After controlling for unobserved heterogeneity and reverse causality biases we find that network at home seems to be the most important determinant of the migrant’s intention to return home within five and ten years.

Assessing the role of social networks on migrant labor market outcomes: Evidence from a representative immigrant survey

What role do social networks play in determining migrant labor market outcomes? We examine this question using data from a random sample of 1500 immigrants living in Ireland. We propose a theoretical model formally predicting that immigrants with more contacts have additional access to job offers, and are therefore better able to become employed and choose higher paid jobs. Our empirical analysis confirms these findings, while focusing more generally on the relationship between migrants’ social networks and a variety of labor market outcomes (namely wages, employment, occupational choice and job security), contrary to the literature. We find evidence that having one more contact in the network is associated with an increase of 11pp in the probability of being employed and with an increase of about 100 euros in the average salary. However, our data is not suggestive of a network size effect on occupational choice and job security. Our findings are robust to sample selection and other endogeneity concerns.

`When I'm sixty-four': old age, family values, and private financial transfers

Private financial transfers are becoming more and more important as ageing levels increase in Europe, with elders acting as both givers and receivers. Our study is divided in two main parts. In the first part we analyse the determinants of private financial transfers, using the Survey of Health, Ageing, and Retirement in Europe (SHARE). In the second part we analyse the importance of family values for these transfers, combining SHARE with European Values Study. We show that family functions as the main agent of private transfers. We conclude that family values drive financial transfers, mainly gifts provided by elderly individuals. We find that receipts by old-aged people are more related with need cases, such as illness and poorness; moreover, for these particular cases, family network plays a very important role, working as a safety net.

Predicting market movement with Artificial Neural Networks

This paper presents an application of an Artificial Neural Network (ANN) to the prediction of stock market direction in the US. Using a multilayer perceptron neural network and a backpropagation algorithm for the training process, the model aims at learning the hidden patterns in the daily movement of the S&P500 to correctly identify if the market will be in a Trend Following or Mean Reversion behavior. The ANN is able to produce a successful investment strategy which outperforms the buy and hold strategy, but presents instability in its overall results which compromises its practical application in real life investment decisions.

As necessidades e redes de apoio de famílias de pessoas com perturbação do espectro do autismo

RESUMO: O objectivo do presente estudo consistiu em avaliar as necessidades de apoio de 63 pais com filhos (crianças, jovens ou adultos) com Perturbação do Espectro Autista (PEA), no que diz respeito a: (1) necessidades de apoio identificadas pelos pais, (2) redes de suporte destes pais e (3) relação entre necessidades de apoio e características dos pais e filhos. Todos os pais tinham participado no 1º nível do projecto nacional intitulado “Oficinas de Pais/Bolsas de Pais” – o Grupo de Apoio Emocional (GAE). No sentido de verificar se ocorreram mudanças nas suas necessidades de apoio, avaliou-se o antes (momento I) e o depois do GAE (momento II). Utilizou-se a Escala de Funções de Apoio Social (Dunst, Trivette, & Deal, 1988) para avaliar as necessidades de apoio e a Escala de Apoio Social (Dunst, Trivette, & Deal, 1988) para avaliar as redes de apoio social. Os resultados demonstram que os pais de pessoas com PEA apresentam (tanto antes como após a frequência nas oficinas do GAE) sobretudo necessidades de apoio de carácter emocional e profissional, e menos necessidades de carácter prático. Para suprir as necessidades de apoio, antes e após o GAE, estes pais recorreram, numa primeira opção, ao cônjuge, aos profissionais e posteriormente aos amigos. Os vizinhos constituíram a rede de apoio social a quem menos recorreram. Apesar de algumas diferenças observadas entre o momento I e momento II, estas não foram estatisticamente significativas nem para as necessidades de apoio, nem para as redes de apoio social.------------------------- ABSTRACT: The study aimed to evaluate the support needs of 63 parents of children, adolescents and adults with Autistic Spectrum Disorder (ASD), concerning three aspects: (1) support needs that parents identified as major target, (2) social support network of these parents, and (3) the relationship between support needs and parent and children characteristics. All parents had participated in the first level of the national project “Oficinas de Pais/Bolsas de Pais” - the Emotional Support Group (ESG). In order to verify if any changes occurred in the needs of support, evaluation was carried before (moment I) and after (moment II) the ESG. In this context, parents filled the Supports Function Scale (Dunst, Trivette, & Deal, 1988), which evaluated their different needs of support, and also the Social Supports Scale (Dunst, Trivette & Deal, 1988) which in turn evaluated their social support network. The results showed that parents of children with ASD, both before and after the ESG, revealed emotional and professional needs and, in a less extent, also practical needs. To address the referred needs (before and after the ESG) these parents seek in the first place the support of their spouse, then that of professionals and, later on, that of friends. Neighbours are the support that parents least address. Despite some observed differences in support needs and social support networks between the two moments, these were, however, not statistically significant.

Using artificial neural networks to generate trading signals for crude oil, copper and gold futures

In this thesis, a feed-forward, back-propagating Artificial Neural Network using the gradient descent algorithm is developed to forecast the directional movement of daily returns for WTI, gold and copper futures. Out-of-sample back-test results vary, with some predictive abilities for copper futures but none for either WTI or gold. The best statistically significant hit rate achieved was 57% for copper with an absolute return Sharpe Ratio of 1.25 and a benchmarked Information Ratio of 2.11.

The family Trypetheliaceae (Loculoascomycetes: lichenized Melanommatales) in Amazonian Brazil.

The family Trypetheliaceae is redefined including a key to the genera. Exiliseptum gen. nov. is described. Keys to the species are provided for the six genera which occur in Amazonian Brazil along with brief comments on the three other genera. Thirty-five species are included, tem new species described and ten new combinations proposed.

O âmbito de aplicação material da legislação de proteção de dados pessoais e o tratamento de imagem por pessoa singular

Images have gained a never before seen importance. Technological changes have given the Information Society extraordinary means to capture, treat and transmit images, wheter your own or those of others, with or without a commercial purpose, with no boundaries of time or country, without “any kind of eraser”. From the several different ways natural persons may engage in image processing with no commercial purpose, the cases of sharing pictures through social networks and video surveillance assume particular relevance. Consequently there are growing legitimate concerns with the protection of one's image, since its processing may sometimes generate situations of privacy invasion or put at risk other fundamental rights. With this in mind, the present thesis arises from the question: what are the existent legal instruments in Portuguese Law that enable citizens to protect themselves from the abusive usage of their own pictures, whether because that image have been captured by a smartphone or some video surveillance camera, whether because it was massively shared through a blog or some social network? There is no question the one's right to not having his or her image used in an abusive way is protected by the Portuguese constitution, through the article 26th CRP, as well as personally right, under the article 79th of the Civil Code, and finally through criminal law, articles 192nd and 193rd of the Criminal Code. The question arises in the personal data protection context, considering that one's picture, given certain conditions, is personal data. Both the Directive 95/46/CE dated from 1995 as well as the LPD from 1998 are applicable to the processing of personal data, but both exclude situations of natural persons doing so in the pursuit of activities strictly personal or family-related. These laws demand complex procedures to natural persons, such as the preemptive formal authorisation request to the Data Protection National Commission. Failing to do so a natural person may result in the application of fines as high as €2.500,00 or even criminal charges. Consequently, the present thesis aims to study if the image processing with no commercial purposes by a natural person in the context of social networks or through video surveillance belongs to the domain of the existent personal data protection law. To that effect, it was made general considerations regarding the concept of video surveillance, what is its regimen, in a way that it may be distinguishable from Steve Mann's definition of sousveillance, and what are the associated obligations in order to better understand the concept's essence. The application of the existent laws on personal data protection to images processing by natural persons has been analysed taking into account the Directive 95/46/CE, the LPD and the General Regulation. From this analysis it is concluded that the regimen from 1995 to 1998 is out of touch with reality creating an absence of legal shielding in the personal data protection law, a flaw that doesn't exist because compensated by the right to image as a right to personality, that anyway reveals the inability of the Portuguese legislator to face the new technological challenges. It is urgent to legislate. A contrary interpretation will evidence the unconstitutionality of several rules on the LPD due to the obligations natural persons are bound to that violate the right to the freedom of speech and information, which would be inadequate and disproportionate. Considering the recently approved General Regulation and in the case it becomes the final version, the use for natural person of video surveillance of private spaces, Google Glass (in public and private places) and other similar gadgets used to recreational purposes, as well as social networks are subject to its regulation only if the images are shared without limits or existing commercial purposes. Video surveillance of public spaces in all situations is subject to General Regulation provisions.

Assessing the role of social networks on migrant labor market outcomes: Evidence from a representative immigrant survey

What role do social networks play in determining migrant labor market outcomes? We examine this question using data from a random sample of 1500 immigrants living in Ireland. We propose a theoretical model formally predicting that immigrants with more contacts have additional access to job offers, and are therefore better able to become employed and choose higher paid jobs. Our empirical analysis confirms these findings, while focusing more generally on the relationship between migrants’ social networks and a variety of labor market outcomes (namely wages, employment, occupational choice and job security), contrary to the literature. We find evidence that having one more contact in the network is associated with an increase of 11pp in the probability of being employed and with an increase of about 100 euros in the average salary. However, our data is not suggestive of a network size effect on occupational choice and job security. Our findings are robust to sample selection and other endogeneity concerns.

A new credit monitoring framework for agents' networks

The purpose of this work is to develop a practicable approach for Telecom firms to manage the credit risk exposition to their commercial agents’ network. Particularly it will try to approach the problem of credit concession to clients’ from a corporation perspective and explore the particular scenario of agents that are part of the commercial chain of the corporation and therefore are not end-users. The agents’ network that served as a model for the presented study is composed by companies that, at the same time, are both clients and suppliers of the Telecommunication Company. In that sense the credit exposition analysis must took into consideration all financial fluxes, both inbound and outbound. The current strain on the Financial Sector in Portugal, and other peripheral European economies, combined with the high leverage situation of most companies, generates an environment prone to credit default risk. Due to these circumstances managing credit risk exposure is becoming increasingly a critical function for every company Financial Department. The approach designed in the current study combined two traditional risk monitoring tools: credit risk scoring and credit limitation policies. The objective was to design a new credit monitoring framework that is more flexible, uses both external and internal relationship history to assess risk and takes into consideration commercial objectives inside the agents’ network. Although not explored at length, the blueprint of a Credit Governance model was created for implementing the new credit monitoring framework inside the telecom firm. The Telecom Company that served as a model for the present work decided to implement the new Credit Monitoring framework after this was presented to its Executive Commission.

Crowdfunding

Crowdfunding, as we know it today, is a very recent activity that was born almost accidentally in the end of the 90’s decade. Due to the advent of the internet and the social networks, entrepreneurs are now able to promote their projects to a very large community. Whether it is composed by family, friends, acquaintances or simply people that are interested in the same topic or share the passion, the community is able to fund new ventures by individually investing modest amounts of money. In return, the entrepreneur can offer symbolic rewards, shares or other financial returns. New crowdfunding platforms are born almost every day all over the world, offering a new way of raising capital for their projects or a new way to invest their money in innovative ventures. Although crowdfunding is still finding its place in the financial services, successful cases such as Kickstarter demonstrate the power of the crowd in boosting creativity and productivity, financing thousands of projects by raising millions of dollars from thousands of investors. Due to regulatory restrictions, the most prominent model for now is reward-based crowdfunding, where the investors are prized with symbolic returns or privileged access to the products or services offered by the entrepreneurs. Other models such as peer-to-peer lending are also surging, allowing borrowers access to capital at a lower cost compared to so-called traditional financial institutions, and offering lenders a higher rate of return. But when it comes to offering shares to investors, i.e. using equity-based crowdfunding, entrepreneurs face regulatory obstacles in almost every country, where legislation was passed decades ago with the objective of promoting financially-capable ventures and protecting investors. Access to capital has become more difficult after the global economic recession of 2008, and for most countries it will not get easier in the near future, leaving start-ups and small enterprises with few options to start or expand their operations. In this study we attempt to answer the following research questions: how has equity-based crowdfunding evolved since its creation? Where and how has equity-based crowdfunding been implemented so far? What are the constraints and opportunities for implementing equity-crowdfunding in the world, and more particularly in Portugal? Finally, we will discuss the risks of crowdfunding and reflect on the future of this industry.

The relationship between the education level of successor's and the firm performance in German publicly listed family firms- an empirical analysis

The purpose of this thesis is to investigate how far the education level of the second or third generation of publicly traded German family firms affects the post-succession firm performance. By conducting a correlational and regression design, the aim is to examine how several variables influence the performance of family firms. Performance measures, for example ROA and Tobin’s q and variables, like Education level and succession periods, examine analytically that a positive succession trend will occur. However, with the used model, only a less rigid model shows empirical evidence.