Channel modelling for MIMO systems

Systems equipped with multiple antennas at the transmitter and at the receiver, known as MIMO (Multiple Input Multiple Output) systems, offer higher capacities, allowing an efficient exploitation of the available spectrum and/or the employment of more demanding applications. It is well known that the radio channel is characterized by multipath propagation, a phenomenon deemed problematic and whose mitigation has been achieved through techniques such as diversity, beamforming or adaptive antennas. By exploring conveniently the spatial domain MIMO systems turn the characteristics of the multipath channel into an advantage and allow creating multiple parallel and independent virtual channels. However, the achievable benefits are constrained by the propagation channel’s characteristics, which may not always be ideal. This work focuses on the characterization of the MIMO radio channel. It begins with the presentation of the fundamental results from information theory that triggered the interest on these systems, including the discussion of some of their potential benefits and a review of the existing channel models for MIMO systems. The characterization of the MIMO channel developed in this work is based on experimental measurements of the double-directional channel. The measurement system is based on a vector network analyzer and a two-dimensional positioning platform, both controlled by a computer, allowing the measurement of the channel’s frequency response at the locations of a synthetic array. Data is then processed using the SAGE (Space-Alternating Expectation-Maximization) algorithm to obtain the parameters (delay, direction of arrival and complex amplitude) of the channel’s most relevant multipath components. Afterwards, using a clustering algorithm these data are grouped into clusters. Finally, statistical information is extracted allowing the characterization of the channel’s multipath components. The information about the multipath characteristics of the channel, induced by existing scatterers in the propagation scenario, enables the characterization of MIMO channel and thus to evaluate its performance. The method was finally validated using MIMO measurements.

What a girl's gotta do: the labor of the biopolitical celebrity in austerity Britain

This article debunks the widespread view that young female celebrities, especially those who rise to fame through reality shows and other forms of media-orchestrated self-exposure, dodge “real” work out of laziness, fatalism, and a misguided sense of entitlement. Instead, the authors argue that becoming a celebrity in a neoliberal economy such as that of the United Kingdom, where austerity measures disproportionately disadvantage the young, women, and the poor, is not as irregular or exceptional a choice as previously thought, especially since the precariousness of celebrity earning power adheres to the current demands of the neoliberal economy on its workforce. What is more, becoming a celebrity involves different forms of labor that are best described as biopolitical, since such labor fully involves and consumes the human body and its capacities as a living organism. Weight gain and weight loss, pregnancy, physical transformation through plastic surgery, physical symptoms of emotional distress, and even illness and death are all photographically documented and supplemented by extended textual commentary, usually with direct input from the celebrity, reinforcing and expanding on the visual content. As well as casting celebrity work as labor, the authors also maintain that the workings of celebrity should always be examined in the context of wider cultural, social and real economies.

Model comparison for temperature estimation inside buildings

This paper presents a comparison between a physical model and an artificial neural network model (NN) for temperature estimation inside a building room. Despite the obvious advantages of the physical model for structure optimisation purposes, this paper will test the performance of neural models for inside temperature estimation. The great advantage of the NN model is a big reduction of human effort time, because it is not needed to develop the structural geometry and structural thermal capacities and to simulate, which consumes a great human effort and great computation time. The NN model deals with this problem as a “black box” problem. We describe the use of the Radial Basis Function (RBF), the training method and a multi-objective genetic algorithm for optimisation/selection of the RBF neural network inputs and number of neurons.

L'appropriation d'un dispositif hybride en formation pour adultes le cas du Campus numérique à l'ESSCA

This thesis focuses on the study of setting up a system of innovative distance learning and its appropriation by the involved actors. The researcher tries to understand or to explain the ownership of an innovative educational context, both from a technology and pedagogy, through the mobilization of the actors of the system, and specifically their dynamic capacities. The aim of this research is to clarify the components of such a mobilization, and develop an explanatory model that values the dynamic capacity of actors, and mainly their absorptive capacities. The research strategy is a process case study research: the appropriation by the actors of the ESSCA (École Supérieure des Faculté des sciences Commerciales d'Angers, France), and by the institution itself, of a training distance learning device. The study is located in a interpretative paradigm. Qualitative data were collected since the beginning of the process, ie since 2001. First, the analysis of the appropriation process reveals a pattern of conditions that will allow the recruitment of actors, and promote ownership. The results highlight the crucial role of a common language for all from a structured approach to translation, the need to promote collaboration operations, and given the fundamental motivation for both individual and institutional. Next, the analysis of the appropriation process highlights a procedural model of the absorptive capacity of the institution and its actors. To estimate the value of new knowledge, the actors will be based on prior knowledge from the external domain or from the institution. Feeding their motivation, they will acquire new knowledge to assimilate and transform in the laboratory and prototype stages. The project stage will see the capacity of actors to use this knowledge to generate new knowledge for transfer to other training programs.

Biopolymers - facts and statistics

The IfBB – Institute for Bioplastics and Biocomposites is a research institute within the Hochschule Hannover, University of Applied Sciences and Arts, which was established in 2011 to respond to the growing need for expert knowledge in the area of bioplastics. With its practice-oriented research and its collaboration with industrial partners, the IfBB is able to shore up the market for bioplastics and, in addition, foster unbiased public awareness and understanding of the topic. As an independent research-led expert institution for bioplastics, the IfBB is willing to share its expertise, research findings and data with any interested party via the Internet, online and offline publications or at fairs and conferences. In carrying on these efforts, substantial information regarding market trends, processes and resource needs for bioplastics is being presented here in a concise format, in addition to the more detailed and comprehensive publication and “Engineering Biopolymers”1. One of our main concerns is to furnish a more rational basis for discussing bioplastics and use fact-based arguments in the public discourse. Furthermore, “Biopolymers – facts and statistics” aims to provide specific, qualified answers easily and quickly for decision-makers in particular from public administration and the industrial sector. Therefore, this publication is made up like a set of rules and standards and largely foregoes textual detail. It offers extensive market-relevant and technical facts presented in graphs and charts, which means that the information is much easier to grasp. The reader can expect comparative market figures for various materials, regions, applications, process routes, agricultural land use or resource consumption, production capacities, geographic distribution, etc.

Desenho, arte e criatividade : um projeto pedagógico centrado no desenvolvimento pessoal

Relatório da Prática de Ensino Supervisionada, Mestrado em Ensino de Artes Visuais, Universidade de Lisboa, 2011

The role of reciprocal regulation between TAL1 and miRNA expression in T-cell leukemia progression

Tese de doutoramento, Ciências Biomédicas (Biologia Celular e Molecular), Universidade de Lisboa, Faculdade de Medicina, 2015

Design e auto-produção : novos paradigmas para o design de artefactos na sociedade pós-industrial : a contribuição das tecnologias digitais

Tese de doutoramento, Belas-Artes (Design de Equipamento), Universidade de Lisboa, Faculdade de Belas-Artes, 2015

Identity, Well-being and Effectiveness: the Emotional Contexts of Teaching

This paper draws on findings from a four‐year longitudinal research project, commissioned by the Department for Education and Skills (DfES), which investigated Variations in Teachers’ Work, Lives and Effectiveness (VITAE). Drawing on data gathered from 300 teachers working in 100 primary and secondary schools in England, the research identified associations between commitment and effectiveness (perceived and in terms of pupil attainment) and found that there were more, and less, effective teachers in each of six professional life phases. It found that teachers in each of these phases experienced a number of different scenarios that challenged their abilities to sustain their commitment (i.e. remain resilient). This paper discusses how these impact, positively and negatively, on teachers’ capacities for sustaining their initial commitment and associations between identity, well‐being and effectiveness. It finds that teacher identities are neither intrinsically stable nor intrinsically fragmented, but that they can be more, or less, stable and more or less fragmented at different times and in different ways according to the influence of the interaction of a number of personal, professional and situated factors. The extent to which teachers are able to and are supported in managing the scenarios they experience will determine their sense of effectiveness.

Application of Decision-Making Theory to the Regulation of Muscular Work Rate During Self-Paced Competitive Endurance Activity.

Successful participation in competitive endurance activities requires continual regulation of muscular work rate in order to maximise physiological performance capacities, meaning that individuals must make numerous decisions with regards to the muscular work rate selected at any point in time. Decisions relating to the setting of appropriate goals and the overall strategic approach to be utilised are made prior to the commencement of an event, whereas tactical decisions are made during the event itself. This review examines current theories of decision-making in an attempt to explain the manner in which regulation of muscular work is achieved during athletic activity. We describe rational and heuristic theories, and relate these to current models of regulatory processes during self-paced exercise in an attempt to explain observations made in both laboratory and competitive environments. Additionally, we use rational and heuristic theories in an attempt to explain the influence of the presence of direct competitors on the quality of the decisions made during these activities. We hypothesise that although both rational and heuristic models can plausibly explain many observed behaviours in competitive endurance activities, the complexity of the environment in which such activities occur would imply that effective rational decision-making is unlikely. However, at present, many proposed models of the regulatory process share similarities with rational models. We suggest enhanced understanding of the decision-making process during self-paced activities is crucial in order to improve the ability to understand regulation of performance and performance outcomes during athletic activity.

Considering the relationship between freight transport and urban form

There has been much discussion since the mid-1980s about the relationship between transport and urban form. However, all of this body of research has concerned itself with passenger transport (i.e. the movement of people). This report is intended as an initial investigation into the relationship between road freight transport and urban form. Important trends in road freight transport and logistics and the land use associated with these activities are discussed. Data about road freight transport activity by heavy goods vehicles (HGVs) in Britain that has been disaggregated from a UK government survey is analysed to investigate the nature of urban freight operations in sixteen selected urban areas. This includes analysis of the efficiency and transport intensity of these operations on journeys to, from and within each urban area. Scenarios concerning urban freight operations based on reductions in length of haul, and improvements in vehicle lading factors, vehicle carrying capacities and empty running are constructed in order to investigate the potential effect of such changes on the vehicle kilometres performed on journeys to, from and within the sixteen urban areas.

Investigating relationships between road freight transport, facility location, logistics management and urban form

This paper examines road freight transport activity and its relationship with facility location, logistics management and urban form through an analysis of 14 selected urban areas in the UK. Improved understanding of this relationship will assist planners when making transport and land use decisions. The findings suggest that several geographical, spatial and land use factors have important influences on freight activity in urban areas. Commercial and industrial land use patterns affect the types and quantities of goods produced, consumed, and hence the total quantity of freight transport handled. This also influences the distances over which goods are moved and by what specific mode. There has been relatively low growth in warehousing in many of the selected areas over the last decade compared to the national average as well suburbanisation of warehousing in some locations. This affects the origin and destination of journeys visiting these facilities and typically increases the distance of such journeys. A greater proportion of road freight has been shown to be lifted on internal journeys in large urban areas than in smaller ones. Journeys within urban areas have been shown to be less efficient than journeys to and from the urban area in the 14 locations studied due to the much smaller average vehicle carrying capacities and lower lading factors for journeys within urban areas. The length of haul on journeys to and from urban areas studied was found to be greatest for those areas with a major seaport and/or which were geographically remote. This affects the road freight transport intensity of goods transport journeys.

The potential for neighbourhood regeneration in a period of austerity: changing forms of neighbourhood governance in two cities

Localism is an active political strategy, developed in a period of austerity by the UK's coalition government as a justification for the restructuring of state-civil society relationships. The deprived neighbourhood has long been a site for service delivery and a scale for intervention and action, giving rise to a variety of forms of neighbourhood governance. Prior international comparative research indicated convergence with the US given the rise of the self-help conjuncture and the decline of neighbourhood governance as a medium of regeneration. The subsequent shift in the UK paradigm from ‘big’ to ‘small state’ localism and deficit-reducing cuts to public expenditure confirm these trends, raising questions about the forms of neighbourhood governance currently being established, the role being played by local and central government, and the implications for neighbourhood regeneration. Two emerging forms of neighbourhood governance are examined in two urban local authorities and compared with prior forms examined in earlier research in the case study sites. The emerging forms differ significantly in their design and purpose, but as both are voluntary and receive no additional funding, better organised and more affluent communities are more likely to pursue their development. While it is still rather early to assess the capacity of these forms to promote neighbourhood regeneration, the potential in a period of austerity appears limited. Reduced funding for local services increases the imperative to self-help, while rights to local voice remain limited and the emerging forms provide little scope to influence (declining) local services and (still centralised) planning decisions, especially in neighbourhoods with regeneration needs which are likely to lack the requisite capacities, particularly stores of linking social capital. Initial conclusions suggest greater polarity and the further containment of deprived neighbourhoods.

Rights, Rationality and Reproduction: Balancing Interests in the Abortion Debate

As medical technology has advanced, so too have our attitudes towards the level of control we can or should expect to have over our procreative capacities. This creates a multidimensional problem for the law and family planning services in terms of access to services – whether to avoid conception or terminate a pregnancy – and the negligent provision of these services. These developments go to the heart of our perception of autonomy. Unsurprisingly, these matters also raise a moral dilemma for the law. Distinctively, discourse in this area is dominated by assertions of subjective moral value; in relation to life, to personal choice and to notions of the archetypal family. Against this, I stress that a model of objective morality can answer these challenging questions and resolve the inherent problems of legal regulation. Therefore, I argue that notions of autonomy must be based on a rational, action-based understanding of what it means to be a ‘moral agent’. I claim that from this we might support a legal standard, based on objective rational morality, which can frame our constitutional norms and our conception of justice in these contentious areas. This paper claims that the current regulation of abortion is outdated and requires radical reform. It proposes a scheme that would shift the choice towards the mother (and the father), remove the unnecessarily broad disability ground and involve doctors having a role of counsel (rather than gatekeeper).

Brief response to Ashton and colleagues regarding Fractionating Human Intelligence

Ashton and colleagues concede in their response (Ashton, Lee, & Visser, in this issue), that neuroimaging methods provide a relatively unambiguous measure of the levels to which cognitive tasks co-recruit dif- ferent functional brain networks (task mixing). It is also evident from their response that they now accept that task mixing differs from the blended models of the classic literature. However, they still have not grasped how the neuroimaging data can help to constrain models of the neural basis of higher order ‘g’. Specifically, they claim that our analyses are invalid as we assume that functional networks have uncorrelated capacities. They use the simple analogy of a set of exercises that recruit multiple muscle groups to varying extents and highlight the fact that individual differences in strength may correlate across muscle groups. Contrary to their claim, we did not assume in the original article (Hampshire, High- field, Parkin, & Owen, 2012) that functional networks had uncorrelated capacities; instead, the analyses were specifically designed to estimate the scale of those correlations, which we referred to as spatially ‘diffuse’ factors