Oil hydrocarbon-bacteria interactions in coastal environments

The ability of microorganisms to use oil hydrocarbons as a source of carbon and energy is crucial for environmental oil detoxification. However, there is still a lack of knowledge on fundamental aspects of this process on specific habitats and under different climate scenarios. In the first phase of this work, the culturable fraction of the oil hydrocarbon (OH) degrading bacteria from the sea surface microlayer (SML) of the estuarine system Ria de Aveiro was characterized. In the second phase, the impact of oil contamination on the active bacterial community was studied under climate change scenarios. Pseudomonas emerged as the prevailing genera among OH degrading bacteria in the SML. Moreover, culture-independent methods revealed that the relative abundance and diversity of Gammaproteobacteria, in which Pseudomonas is included, varies along an estuarine gradient of contamination. In order to access the impact of oil contamination on microbial communities under climate change scenarios, an experimental life support system for microcosm experiments (ELLS) was developed and validated for simulation of climate change effects on microbial communities. With the ELSS it is possible to simulate, in controlled conditions, fundamental parameters of the dynamics of coastal and estuarine systems while maintaining community structure in terms of the abundance of the most relevant members of the indigenous bacterial community. A microcosm experiment in which the independent and combined impact of ultraviolet radiation, ocean acidification and oil contamination on microbial communities was conducted. The impact on bacterial communities was accessed with a 16S RNA (cDNA) based barcode pyrosequencing approach. There was a drastic decrease of Desulfobacterales relative abundance after oil contamination under the reduced pH value estimated for 2100, when compared to present values. Since members of this order are known OH degraders, such a significant decrease may have consequences on OH detoxification of contaminated environments under the pH levels of the ocean expected for the future. Metagenome predictions based on the 16S RNA database indicated that several degradation pathways of OH could be affected under oil contamination and reduced water pH. Taken together, the results from this work bring new information on the dynamics of OH degrading bacteria in coastal and estuarine environments under present and future climate scenarios.

Control design for multicast-aware class-based networks

The expectations of citizens from the Information Technologies (ITs) are increasing as the ITs have become integral part of our society, serving all kinds of activities whether professional, leisure, safety-critical applications or business. Hence, the limitations of the traditional network designs to provide innovative and enhanced services and applications motivated a consensus to integrate all services over packet switching infrastructures, using the Internet Protocol, so as to leverage flexible control and economical benefits in the Next Generation Networks (NGNs). However, the Internet is not capable of treating services differently while each service has its own requirements (e.g., Quality of Service - QoS). Therefore, the need for more evolved forms of communications has driven to radical changes of architectural and layering designs which demand appropriate solutions for service admission and network resources control. This Thesis addresses QoS and network control issues, aiming to improve overall control performance in current and future networks which classify services into classes. The Thesis is divided into three parts. In the first part, we propose two resource over-reservation algorithms, a Class-based bandwidth Over-Reservation (COR) and an Enhanced COR (ECOR). The over-reservation means reserving more bandwidth than a Class of Service (CoS) needs, so the QoS reservation signalling rate is reduced. COR and ECOR allow for dynamically defining over-reservation parameters for CoSs based on network interfaces resource conditions; they aim to reduce QoS signalling and related overhead without incurring CoS starvation or waste of bandwidth. ECOR differs from COR by allowing for optimizing control overhead minimization. Further, we propose a centralized control mechanism called Advanced Centralization Architecture (ACA), that uses a single state-full Control Decision Point (CDP) which maintains a good view of its underlying network topology and the related links resource statistics on real-time basis to control the overall network. It is very important to mention that, in this Thesis, we use multicast trees as the basis for session transport, not only for group communication purposes, but mainly to pin packets of a session mapped to a tree to follow the desired tree. Our simulation results prove a drastic reduction of QoS control signalling and the related overhead without QoS violation or waste of resources. Besides, we provide a generic-purpose analytical model to assess the impact of various parameters (e.g., link capacity, session dynamics, etc.) that generally challenge resource overprovisioning control. In the second part of this Thesis, we propose a decentralization control mechanism called Advanced Class-based resource OverpRovisioning (ACOR), that aims to achieve better scalability than the ACA approach. ACOR enables multiple CDPs, distributed at network edge, to cooperate and exchange appropriate control data (e.g., trees and bandwidth usage information) such that each CDP is able to maintain a good knowledge of the network topology and the related links resource statistics on real-time basis. From scalability perspective, ACOR cooperation is selective, meaning that control information is exchanged dynamically among only the CDPs which are concerned (correlated). Moreover, the synchronization is carried out through our proposed concept of Virtual Over-Provisioned Resource (VOPR), which is a share of over-reservations of each interface to each tree that uses the interface. Thus, each CDP can process several session requests over a tree without requiring synchronization between the correlated CDPs as long as the VOPR of the tree is not exhausted. Analytical and simulation results demonstrate that aggregate over-reservation control in decentralized scenarios keep low signalling without QoS violations or waste of resources. We also introduced a control signalling protocol called ACOR Protocol (ACOR-P) to support the centralization and decentralization designs in this Thesis. Further, we propose an Extended ACOR (E-ACOR) which aggregates the VOPR of all trees that originate at the same CDP, and more session requests can be processed without synchronization when compared with ACOR. In addition, E-ACOR introduces a mechanism to efficiently track network congestion information to prevent unnecessary synchronization during congestion time when VOPRs would exhaust upon every session request. The performance evaluation through analytical and simulation results proves the superiority of E-ACOR in minimizing overall control signalling overhead while keeping all advantages of ACOR, that is, without incurring QoS violations or waste of resources. The last part of this Thesis includes the Survivable ACOR (SACOR) proposal to support stable operations of the QoS and network control mechanisms in case of failures and recoveries (e.g., of links and nodes). The performance results show flexible survivability characterized by fast convergence time and differentiation of traffic re-routing under efficient resource utilization i.e. without wasting bandwidth. In summary, the QoS and architectural control mechanisms proposed in this Thesis provide efficient and scalable support for network control key sub-systems (e.g., QoS and resource control, traffic engineering, multicasting, etc.), and thus allow for optimizing network overall control performance.

Majorantes para a ordem de subgrafos induzidos k-regulares

Muitos dos problemas de otimização em grafos reduzem-se à determinação de um subconjunto de vértices de cardinalidade máxima que induza um subgrafo k-regular. Uma vez que a determinação da ordem de um subgrafo induzido k-regular de maior ordem é, em geral, um problema NP-difícil, são deduzidos novos majorantes, a determinar em tempo polinomial, que em muitos casos constituam boas aproximações das respetivas soluções ótimas. Introduzem-se majorantes espetrais usando uma abordagem baseada em técnicas de programação convexa e estabelecem-se condições necessárias e suficientes para que sejam atingidos. Adicionalmente, introduzem-se majorantes baseados no espetro das matrizes de adjacência, laplaciana e laplaciana sem sinal. É ainda apresentado um algoritmo não polinomial para a determinação de umsubconjunto de vértices de umgrafo que induz umsubgrafo k-regular de ordem máxima para uma classe particular de grafos. Finalmente, faz-se um estudo computacional comparativo com vários majorantes e apresentam-se algumas conclusões.

U-TRACER® - the use of communication technology in higher education - an information visualization tool for the context of Portuguese public higher education

Information Visualization is gradually emerging to assist the representation and comprehension of large datasets about Higher Education Institutions, making the data more easily understood. The importance of gaining insights and knowledge regarding higher education institutions is little disputed. Within this knowledge, the emerging and urging area in need of a systematic understanding is the use of communication technologies, area that is having a transformative impact on educational practices worldwide. This study focused on the need to visually represent a dataset about how Portuguese Public Higher Education Institutions are using Communication Technologies as a support to teaching and learning processes. Project TRACER identified this need, regarding the Portuguese public higher education context, and carried out a national data collection. This study was developed within project TRACER, and worked with the dataset collected in order to conceptualize an information visualization tool U-TRACER®. The main goals of this study related to: conceptualization of the information visualization tool U-TRACER®, to represent the data collected by project TRACER; understand higher education decision makers perception of usefulness regarding the tool. The goals allowed us to contextualize the phenomenon of information visualization tools regarding higher education data, realizing the existing trends. The research undertaken was of qualitative nature, and followed the method of case study with four moments of data collection.The first moment regarded the conceptualization of the U-TRACER®, with two focus group sessions with Higher Education professionals, with the aim of defining the interaction features the U-TRACER® should offer. The second data collection moment involved the proposal of the graphical displays that would represent the dataset, which reading effectiveness was tested by end-users. The third moment involved the development of a usability test to the UTRACER ® performed by higher education professionals and which resulted in the proposal of improvements to the final prototype of the tool. The fourth moment of data collection involved conducting exploratory, semi-structured interviews, to the institutional decision makers regarding their perceived usefulness of the U-TRACER®. We consider that the results of this study contribute towards two moments of reflection. The challenges of involving end-users in the conceptualization of an information visualization tool; the relevance of effective visual displays for an effective communication of the data and information. The second relates to the reflection about how the higher education decision makers, stakeholders of the U-TRACER® tool, perceive usefulness of the tool, both for communicating their institutions data and for benchmarking exercises, as well as a support for decision processes. Also to reflect on the main concerns about opening up data about higher education institutions in a global market.

Dinâmicas de envolvimento das pessoas com incapacidade nas atividades turísticas

A promoção de uma sociedade mais inclusiva tem vindo a refletir-se numa progressiva tomada de consciência das dimensões associadas ao turismo acessível para todos. Ao mesmo tempo, no plano discursivo, assume-se cada vez mais o turismo como um bem social de primeira necessidade, essencial na qualidade de vida. No entanto, também é igualmente reconhecido que o acesso às práticas turísticas, por parte de pessoas com incapacidade, continua a ser moldado por dificuldades de vária ordem, às quais o sector do turismo não tem sabido responder, ou, pelo menos, a perceção consciente deste facto social tem sido muito débil e incipiente. Partindo destes pressupostos, a nossa investigação centrou-se, particularmente, na compreensão das dinâmicas de envolvimento e de participação das pessoas com incapacidade nas atividades turísticas. Concretamente, pretendemos analisar os aspetos associados à experiência das pessoas com incapacidade visual ou incapacidade física, identificando os fatores que restringem (inibidores) e os fatores que afetam a decisão de viajar de forma positiva (os facilitadores), procurando compreender como é que as pessoas se adaptam e se tornam viajantes ativos. Para a concretização deste objetivo utilizou-se um estudo qualitativo, baseado em entrevistas longas, que procurou dar voz aos atores com incapacidade visual e física. O tratamento da informação recolhida foi efetuado com base na análise de conteúdo de tipo temático-categorial. Os resultados assim obtidos permitem extrair as seguintes conclusões principais: a participação em atividades turísticas por parte das pessoas com incapacidade física e visual resulta de um processo dinâmico e interativo, no qual intervêm múltiplos fatores, com influência positiva ou negativa, na confluência do seu contexto pessoal, da sua condição de incapacidade e do seu ambiental social, com um impacto variável nas diferentes etapas do processo.

Avaliação ambiental estratégica de Planos Diretores Municipais

O objetivo do presente relatório de estágio é clarificar e sistematizar alguns conceitos associados à Avaliação Ambiental Estratégica (AAE) de Instrumentos de Gestão Territorial (IGT), e expor a aplicação desta ferramenta a um Plano Diretor Municipal (PDM). A Avaliação Ambiental Estratégica é um instrumento de avaliação da política de ambiente aplicado ao processo de planeamento para garantir que as considerações ambientais são integradas, a par das questões económicas e sociais, durante a fase de elaboração de planos e programas e antes da sua aprovação, com a finalidade de promover a adoção de soluções mais sustentáveis e o estabelecimento de diretrizes de seguimento que minimizem os impactes negativos. Em Portugal, a aplicação desta ferramenta de avaliação é um procedimento obrigatório desde a transposição da Diretiva 2001/42/CE, de 27 de junho para a ordem jurídica interna pelo Decreto-Lei n.º 232/2007, de 15 de junho. O processo de AAE desenvolve-se em três fases essenciais: o estabelecimento dos fatores críticos para a decisão, a avaliação e o seguimento. Este relatório de estágio analisa a aplicação da AAE à 1ª revisão do Plano Diretor Municipal de Castelo de Vide, onde se conclui que a identificação das oportunidades e riscos resultantes da estratégia de desenvolvimento territorial contribui para a prossecução do desenvolvimento sustentável e para uma tomada de decisão mais adequada.