As reações do mercado acionista e obrigacionista dos GIPSI às notícias da Troika durante o período de crise financeira: 2010-2013

A zona euro e mais concretamente o conjunto de países constituído por Grécia, Itália, Portugal, Espanha e Irlanda chamado de GIPSI, atravessam uma das maiores crises desde a Grande Depressão. De forma a ajudar estes países mais afetados, um conjunto de organizações internacionais (FMI/BCE/CE) apelidado de Troika, tem unido esforços para debelar as dificuldades de financiamento e criarem políticas de reforma com o objetivo de devolver a independência e potenciar o crescimento económico dos mesmos. As ações e comunicados destas organizações passaram assim a gozar de uma maior visibilidade e interesse por parte dos investidores. Tendo isso em conta, neste trabalho estudamos o impacto das notícias da Troika nos mercados acionista e obrigacionista dos GIPSI, com um maior foco no mercado português. Em Portugal não encontramos evidência de que as notícias diretamente relacionadas com as ações e comunicações da Troika têm efetivamente impactos significativos, quer no mercado acionista, quer no obrigacionista. No entanto, as notícias de carácter internacional sobre a crise, respeitantes aos outros países afetados, impactaram de forma significativa o PSI 20, especialmente quando estas foram boas, assim como outras notícias relativas a avaliações, anúncios de apoio ou críticas de outras organizações europeias e mundiais, bem como como de líderes de países intervenientes na ajuda aos países afetados e anúncios macroeconómicos, sendo que aqui esse impacto foi mais sentido nas más notícias. No mercado obrigacionista, voltamos a ter impactos significativos dos mesmos tipos de notícias juntando-se aqui as notícias relativas às medidas tomadas pelo Governo português e outros agentes governamentais. Os restantes mercados, Espanha e Grécia apresentaram impactos significativos no mercado acionista e obrigacionista, o que nos leva a confirmar estudos anteriores de que notícias relacionadas com a crise têm efeitos para além do país visado e impactam de forma significativa outros mercados, em especial os mais afetados.

Context-awareness privacy in data communications

Internet users consume online targeted advertising based on information collected about them and voluntarily share personal information in social networks. Sensor information and data from smart-phones is collected and used by applications, sometimes in unclear ways. As it happens today with smartphones, in the near future sensors will be shipped in all types of connected devices, enabling ubiquitous information gathering from the physical environment, enabling the vision of Ambient Intelligence. The value of gathered data, if not obvious, can be harnessed through data mining techniques and put to use by enabling personalized and tailored services as well as business intelligence practices, fueling the digital economy. However, the ever-expanding information gathering and use undermines the privacy conceptions of the past. Natural social practices of managing privacy in daily relations are overridden by socially-awkward communication tools, service providers struggle with security issues resulting in harmful data leaks, governments use mass surveillance techniques, the incentives of the digital economy threaten consumer privacy, and the advancement of consumergrade data-gathering technology enables new inter-personal abuses. A wide range of fields attempts to address technology-related privacy problems, however they vary immensely in terms of assumptions, scope and approach. Privacy of future use cases is typically handled vertically, instead of building upon previous work that can be re-contextualized, while current privacy problems are typically addressed per type in a more focused way. Because significant effort was required to make sense of the relations and structure of privacy-related work, this thesis attempts to transmit a structured view of it. It is multi-disciplinary - from cryptography to economics, including distributed systems and information theory - and addresses privacy issues of different natures. As existing work is framed and discussed, the contributions to the state-of-theart done in the scope of this thesis are presented. The contributions add to five distinct areas: 1) identity in distributed systems; 2) future context-aware services; 3) event-based context management; 4) low-latency information flow control; 5) high-dimensional dataset anonymity. Finally, having laid out such landscape of the privacy-preserving work, the current and future privacy challenges are discussed, considering not only technical but also socio-economic perspectives.

Vaness: DNS for nomadic users in vehicular networks

Vehicular networks, also known as VANETs, are an ad-hoc network formed by vehicles and road-side units. Nowadays they have been attracting big interest both from researchers as from the automotive industry. With the upcoming of automotive specific operating systems and self-driving cars, the use of applications on vehicles and the integration with common mobile devices is becoming a big part of VANETs. Although many advances have been made on this field, there is still a big discrepancy between the communication layer services provided by VANETs and the user level services, namely those accessible through mobile applications on other networks and technologies. Users and developers are accustomed to user-to-user or user-tobusiness communication without explicit concerns related with the available communication transport layer. Such is not possible in VANETs since people may use more than one vehicle. However, to send a message to a specific user in these networks, there is a need to know the ID of the vehicle where the user is, meaning that there is a lack of services that map each individual user to VANETs endpoint (vehicle identification). This dissertation work proposes VANESS, a naming service as a resource to support user-to-user communication within a heterogeneous scenario comprising typical ISP scenario and VANETs focused on mobile devices. The proposed system is able to map the user to an end point either locally (i.e. there is not internet connection at all), online (i.e. system is not in a vehicular network but has direct internet connection) and using a gateway (i.e. the system is in a vehicular network where some of the nodes have internet access and will act as a gateway). VANESS was fully implemented on android OS with results proving his viability, and partially on iOS showing its multiplatform capabilities.

Capacity forecasting for radio access networks

The mobile networks market (focus of this work) strategy is based on the consolidation of the installed structure and the optimization of the already existent resources. The increasingly competition and aggression of this market requires, to the mobile operators, a continuous maintenance and update of the networks in order to obtain the minimum number of fails and provide the best experience for its subscribers. In this context, this dissertation presents a study aiming to assist the mobile operators improving future network modifications. In overview, this dissertation compares several forecasting methods (mostly based on time series analysis) capable of support mobile operators with their network planning. Moreover, it presents several network indicators about the more common bottlenecks.