Reconfigurable middleware architectures for large scale sensor networks

Wireless sensor networks, in an effort to be energy efficient, typically lack the high-level abstractions of advanced programming languages. Though strong, the dichotomy between these two paradigms can be overcome. The SENSIX software framework, described in this dissertation, uniquely integrates constraint-dominated wireless sensor networks with the flexibility of object-oriented programming models, without violating the principles of either. Though these two computing paradigms are contradictory in many ways, SENSIX bridges them to yield a dynamic middleware abstraction unifying low-level resource-aware task reconfiguration and high-level object recomposition. Through the layered approach of SENSIX, the software developer creates a domain-specific sensing architecture by defining a customized task specification and utilizing object inheritance. In addition, SENSIX performs better at large scales (on the order of 1000 nodes or more) than other sensor network middleware which do not include such unified facilities for vertical integration

Uncertainty Management of Intelligent Feature Selection in Wireless Sensor Networks

Wireless sensor networks (WSN) are envisioned to revolutionize the paradigm of monitoring complex real-world systems at a very high resolution. However, the deployment of a large number of unattended sensor nodes in hostile environments, frequent changes of environment dynamics, and severe resource constraints pose uncertainties and limit the potential use of WSN in complex real-world applications. Although uncertainty management in Artificial Intelligence (AI) is well developed and well investigated, its implications in wireless sensor environments are inadequately addressed. This dissertation addresses uncertainty management issues of spatio-temporal patterns generated from sensor data. It provides a framework for characterizing spatio-temporal pattern in WSN. Using rough set theory and temporal reasoning a novel formalism has been developed to characterize and quantify the uncertainties in predicting spatio-temporal patterns from sensor data. This research also uncovers the trade-off among the uncertainty measures, which can be used to develop a multi-objective optimization model for real-time decision making in sensor data aggregation and samplin

The solar energy consumer agent decision (SECAD) model : addressing complexity through GIS-integrated agent-based modeling

textThis thesis presents a step-by-step implementation of the Solar Energy Consumer Agent Decision (SECAD) model: an empirically-grounded multi-agent model of residential solar photovoltaic (PV) adoption with an integrated geospatial topology. Solar PV diffusion is a complex system with geographic heterogeneity, uncertain information, high financial risk, and important social interaction and feedback effects between consumers. A key limitation for agentbased models in human socio-technical systems is the integration of empirical patterns in the model structure, initialization, and validation efforts. This limitation is addressed though highly granular and interlocking data-streams from the geographic, social network, financial, demographic, and decision-making process of real households in the study. The fitted and validation model is used to simulate implementation of potential policies to inform decision-makers: i) Targeted informational dissemination campaigns, ii) Tiered rebates, iii) Locational pricing, and iv) Alternative rebate schedules. Informational campaigns can increase cumulative installations by as much as 12%, but vary greatly in their effectiveness based on which agents are targeted. Simulations suggest that by lowering the cost barrier to lower wealth households through a slightly higher rebate (+$0.25/Watt), the mean difference in wealth between solar adopters and non adopters could be reduced by 22.6$0.25 higher offering increased the percentage of adopters in the target area from less than 1% to over 10%. Relative to flatter rebate schedules, sharply decreasing schedules are effective in terms of motivating adoption but inefficient in small markets. It is our hope that this work will provide a working example for other agent-based models of human socio-technical systems as well as provide insight into the likely outcomes of novel policy-levers such as those described above.Energy and Earth ResourcesPublic Affair

Manufacturing the Digital Advertising Audience

How does a new medium create its audience? This study takes the business model of commercial media as its starting point and identifies industrial audience measurement as a constitutive operation in creating the sellable asset of advertising- funded companies. The study employs a qualitative case study design to analyse how a mobile virtual network operator (MVNO) company harnesses digital behavioural records generated by computational network infrastructure to turn network subscribers into an advertising audience product. The empirical evidence is based on a three-months intensive fieldwork at the company office. The analysis reveals comprehensiveness, openness and granularity as the historically new attributes of computational data vis-à-vis traditional audience measurement arrangements. These attributes are then juxtaposed with four kinds of business analytical operations (automatic data aggregation procedures, the use of software reporting tools, organizational reporting practices and custom analyses) observed at the research site to assess how does computational media environment rule key audiencemaking practices. Finally, the implications of this analytical infrastructure are reflected upon three sets of organizational practices. The theoretical framework for the analysis is composed by critically assessing constructivist approaches (SCOT, ANT and sociomateriality) for studying technology and by discussing an approach inspired by critical realism to overcome their limitations with respect to the objectives of the study. The findings contribute toward innovating new digital services, information systems (IS) theory and the study of media audiences. The case opens up considerable complexity involved in establishing a new kind of advertising audience and, more generally, a platform business. Sending out advertisements is easy compared to demonstrating that somebody is actually receiving them. The three computational attributes both extend and provide summative validity for mid-range theorizing on how computational objects mediate organizational practices and processes. Finally, the analysis reveals an interactive nature of digital audience stemming from the direct and immediate behavioural feedback in an audiencemaking cycle

Policy and regulatory barriers to local energy markets in Great Britain

EPG Working Paper: EPG 1801The requirement to decarbonise the GB electricity system, alongside the falling costs of renewable technologies and developments in IT capabilities, provides GB with an opportunity for systemic change in the way that electricity is produced and sold, with the potential to enable flexibility markets at the local level given the correct regulatory conditions. The report highlights a range of regulatory and policy barriers to the Local Energy Market (LEM) approach

Incrementando as redes centradas à informaçãopara uma internet das coisas baseada em nomes

The way we use the Internet has been evolving since its origins. Nowadays, users are more interested in accessing contents and services with high demands in terms of bandwidth, security and mobility. This evolution has triggered the emergence of novel networking architectures targeting current, as well as future, utilisation demands. Information-Centric Networking (ICN) is a prominent example of these novel architectures that moves away from the current host-centric communications and centres its networking functions around content. Parallel to this, new utilisation scenarios in which smart devices interact with one another, as well as with other networked elements, have emerged to constitute what we know as the Internet of Things (IoT). IoT is expected to have a significant impact on both the economy and society. However, fostering the widespread adoption of IoT requires many challenges to be overcome. Despite recent developments, several issues concerning the deployment of IPbased IoT solutions on a large scale are still open. The fact that IoT is focused on data and information rather than on point-topoint communications suggests the adoption of solutions relying on ICN architectures. In this context, this work explores the ground concepts of ICN to develop a comprehensive vision of the principal requirements that should be met by an IoT-oriented ICN architecture. This vision is complemented with solutions to fundamental issues for the adoption of an ICN-based IoT. First, to ensure the freshness of the information while retaining the advantages of ICN’s in-network caching mechanisms. Second, to enable discovery functionalities in both local and large-scale domains. The proposed mechanisms are evaluated through both simulation and prototyping approaches, with results showcasing the feasibility of their adoption. Moreover, the outcomes of this work contribute to the development of new compelling concepts towards a full-fledged Named Network of Things.A forma como usamos a Internet tem vindo a evoluir desde a sua criação. Atualmente, os utilizadores estão mais interessados em aceder a conteúdos e serviços, com elevados requisitos em termos de largura de banda, segurança e mobilidade. Esta evolução desencadeou o desenvolvimento de novas arquiteturas de rede, visando os atuais, bem como os futuros, requisitos de utilização. As Redes Centradas à Informação (Information-Centric Networking - ICN) são um exemplo proeminente destas novas arquiteturas que, em vez de seguirem um modelo de comunicação centrado nos dispositivos terminais, centram as suas funções de rede em torno do próprio conteúdo. Paralelamente, novos cenários de utilização onde dispositivos inteligentes interagem entre si, e com outros elementos de rede, têm vindo a aparecer e constituem o que hoje conhecemos como a Internet das Coisas (Internet of Things - IoT ). É esperado que a IoT tenha um impacto significativo na economia e na sociedade. No entanto, promover a adoção em massa da IoT ainda requer que muitos desafios sejam superados. Apesar dos desenvolvimentos recentes, vários problemas relacionados com a adoção em larga escala de soluções de IoT baseadas no protocolo IP estão em aberto. O facto da IoT estar focada em dados e informação, em vez de comunicações ponto-a-ponto, sugere a adoção de soluções baseadas em arquiteturas ICN. Neste sentido, este trabalho explora os conceitos base destas soluções para desenvolver uma visão completa dos principais requisitos que devem ser satisfeitos por uma solução IoT baseada na arquitetura de rede ICN. Esta visão é complementada com soluções para problemas cruciais para a adoção de uma IoT baseada em ICN. Em primeiro lugar, assegurar que a informação seja atualizada e, ao mesmo tempo, manter as vantagens do armazenamento intrínseco em elementos de rede das arquiteturas ICN. Em segundo lugar, permitir as funcionalidades de descoberta não só em domínios locais, mas também em domínios de larga-escala. Os mecanismos propostos são avaliados através de simulações e prototipagem, com os resultados a demonstrarem a viabilidade da sua adoção. Para além disso, os resultados deste trabalho contribuem para o desenvolvimento de conceitos sólidos em direção a uma verdadeira Internet das Coisas baseada em Nomes.Programa Doutoral em Telecomunicaçõe

Reconstruction of environmental and climate dynamics using multi-proxy evidence from palaeosols of the Western Cape, South Africa

Includes abstract.Includes bibliographical references.Like many of the world’s subtropical regions, the Western Cape of South Africa is highly sensitive to oscillations in the earth’s climate system triggered by major tectonic changes, local variations in orbital forcing, better known as Milankovitch cycles, and its position at the interface between temperate and tropical circulation systems. Regrettably, a dearth of reliable and continuous palaeoenvironmental records means that relatively little is known about how regional environments have been impacted over centennial to multi-millennial timescales. Palaeosols constitute an important stratigraphic marker for past environments and may provide useful validation of pedogenic and other earth system process models. However, the characterisation and analysis of palaeosols has been a largely neglected source of information in the Western Cape, South Africa. This thesis aims to improve the understanding of the environments and climate dynamics using evidences from palaeosols. Various palaeosol-based proxies including geochemistry, mineralogical, macro- and micromorphological, δ13C and δ18O isotope, and selected physico-chemical properties of palaeosols were studied and records obtained for four sites in the Western Cape. A number of chemical weathering indices and geochemical climofunctions were used to calculate weathering intensities, pedogenesis, palaeotemperature and palaeoprecipitation for the various locations using geochemical and stable isotope data. Results of this study indicate that palaeosol-based proxies have the potential to provide snapshots into the palaeoenvironments and palaeoclimate of Western Cape and may complement previous studies done with other proxies such as pollens and diatoms. For example, the interpretation of the pedofeatures (calcareousness, vertic, gleyic, illuviation) - from the micromorphology - of thepalaeosols suggests cyclic patterns of erosion and deposition that correlate with climate changes of the past. Podzolization and laterization are the principal pedogenic processes responsible for the red palaeosol formation at the Cape Peninsula, while calcification and salinization are accountable for the Quaternary palaeosols. Inferences of gleization and lessivage are only evident in the mid-Miocene palaeosol at Langebaanweg. At LBW, pedogenesis was more advanced in the Mid-Miocene and Early Pliocene layers signifying a more humid and warmer climate with more stable landscape. Two major regional climate cycles were evident at the Cape Peninsula: relatively warm and humid subtropical climate which gave rise to the pedogenically modified buried red palaeosol and dry semi-arid Mediterranean climate under which the soils overlying the stone line is currently forming, as seen from the poor horizonation and translocation of materials. Clay mineral assemblages suggest the Quaternary palaeoclimate of the Western Cape has been predominantly characterised by low precipitation and active coastal erosion, which jointly accounted for poor soil profile development. This is in agreement with the early reports obtained from marine records of the African continent (e.g. deMenocal, 2005). A cross plot of the δ13C and δ18O of the carbonate palaeosols indicates they all formed under strong marine influence and C3 plants have been dominant since late Quaternary