Millimetre Wave Power Measurement

There is currently no traceable power sensor for millimetre wave frequencies above 110 GHz. This thesis investigates a novel approach to remove this limitation by combining the placement of a uniquely designed microchip directly in waveguide. The design of the chip is novel in that it does not rely on a supporting structure or an external antenna when placed in the waveguide. The performance of the design was primarily analysed by computer simulation and verified with the measurement of a scale model. The results show that it is feasible to measure high frequency power by placing a chip directly in waveguide. It is predicted that the chip is able to absorb approximately 60% of incident power. Any further efficiency would require modification of the chip substrate. However, this proposed design should allow the standards institutes a reference that will enable the calibration of equipment to beyond 110 GHz

Stochastic chemical enrichment in metal-poor systems II. Abundance ratios and scatter

A stochastic model of the chemical enrichment of metal-poor systems by core-collapse supernovae is used to study the scatter in stellar abundance ratios. The resulting scatter in abundance ratios, e.g. as functions of the overall metallicity, is demonstrated to be crucially dependent on the as yet uncertain supernovae yields. The observed abundance ratios and their scatters therefore have diagnostic power as regards the yields. The relatively small star-to-star scatter observed in many chemical abundance ratios, e.g. by Cayrel et al. (2004) for stars down to [Fe/H] = -4, is tentatively explained by the averaging of a large number of contributing supernovae and by the cosmic selection effects favoring contributions from supernovae in a certain mass range for the most metal-poor stars. The scatter in observed abundances of alpha-elements is understood in terms of observational errors only, while additional spread in yields or sites of nucleosynthesis may affect the odd-even elements Na and Al. For the iron-group elements we find systematically too high predicted Cr/Fe and Cr/Mg ratios, as well as differences between the different sets of yields, both in terms of predicted abundance ratios and scatter. The semi-empirical yields recently suggested by Francois et al. (2004) are found to lead to scatter in abundance ratios significantly greater than observed, when applied in the inhomogeneous models. "Spurs", very narrow sequences in abundance-ratio diagrams, may disclose a single-supernova origin of the elements of the stars on the sequence. Verification of the existence of such features, called single supernova sequences (SSSs), is challenging. This will require samples of several hundred stars with abundance ratios observed to accuracies of 0.05 dex or better.Comment: 19 pages, 20 figures, accepted for publication in Astronomy & Astrophysic

Study of helicopterroll control effectiveness criteria

A study of helicopter roll control effectiveness based on closed-loop task performance measurement and modeling is presented. Roll control critieria are based on task margin, the excess of vehicle task performance capability over the pilot's task performance demand. Appropriate helicopter roll axis dynamic models are defined for use with analytic models for task performance. Both near-earth and up-and-away large-amplitude maneuvering phases are considered. The results of in-flight and moving-base simulation measurements are presented to support the roll control effectiveness criteria offered. This Volume contains the theoretical analysis, simulation results and criteria development

Global-scale regionalization of hydrologic model parameters

Current state-of-the-art models typically applied at continental to global scales (hereafter called macroscale) tend to use a priori parameters, resulting in suboptimal streamflow (Q) simulation. For the first time, a scheme for regionalization of model parameters at the global scale was developed. We used data from a diverse set of 1787 small-to-medium sized catchments ( 10-10,000 km(2)) and the simple conceptual HBV model to set up and test the scheme. Each catchment was calibrated against observed daily Q, after which 674 catchments with high calibration and validation scores, and thus presumably good-quality observed Q and forcing data, were selected to serve as donor catchments. The calibrated parameter sets for the donors were subsequently transferred to 0.5 degrees grid cells with similar climatic and physiographic characteristics, resulting in parameter maps for HBV with global coverage. For each grid cell, we used the 10 most similar donor catchments, rather than the single most similar donor, and averaged the resulting simulated Q, which enhanced model performance. The 1113 catchments not used as donors were used to independently evaluate the scheme. The regionalized parameters outperformed spatially uniform (i.e., averaged calibrated) parameters for 79% of the evaluation catchments. Substantial improvements were evident for all major Koppen-Geiger climate types and even for evaluation catchments>5000 km distant from the donors. The median improvement was about half of the performance increase achieved through calibration. HBV with regionalized parameters outperformed nine state-of-the-art macroscale models, suggesting these might also benefit from the new regionalization scheme. The produced HBV parameter maps including ancillary data are available via

Creative interactions between visual technology and sound art in a live performance context

For introducing this thesis, it is important to place it in a context of: models of interactivity – systems, systemic work, mediation, participation, collaboration, interfaces, dance, drawing, video, sound, interaction, multimedia, Digital versus analogue, layers, physical time versus performance and film time, physical space versus virtual space, material (paper ink etc.) versus light projection and sound, wearable technology, and to briefly pinpoint artists who are working in relevant ways for the discussion arising. Within dance itself the use of new technology is also varied and has seen the creation of different contexts for Dance The main question is on how to achieve a creative solution for nonintrusive technology for dance expression and a dialogue between different parts like drawing, video, dance improvisation, interactive performative dialogues and sound. By nonintrusive technology one means technology that does not physically interfere with the ability a dancer has to move freely like cables, wires or heavy suits that restrict movement instead of promoting it. Finding a research framework that goes towards this idea is at the forefront of this research as well as testing a system that goes towards this idea of allowing the dancers to perform freely without physical constrictions or barriers. The main research question is therefore split into several smaller items that will be looked at within the body of this research like where did the interaction between Dance and Technology had its roots? This research focuses on finding a way to marry video technology, drawing, sound and live performance from the performer’s point of view, to enhance the performer´s ability to interact with the elements, for the performers freedom to move without technological constrictions. This project is about creating a situation that allows for observation of the performers, exploring and educating themselves through experimenting and experiencing technology brought together thinking about movement itself. It uses improvisation as a language tool to facilitate a dialogue between technology and live performance. ‘LFPF’ is proposing to develop a new approach to relationship between performer, stage and sound better still between performance and its special environment/context. It offers innovative possibilities without being intimidating. Once in place (once set up) it provides a new approach for artists to collaborate, it provides a common ground for Dance Performance and Fine/Sound Artists to merge their skills through experimentation with a live performance as the ultimate goal. ‘LFPF’ – Live Film Performance Facilitator tests and provides a new approach to the relationship between live performance, film and sound when combined in live performance situations. It enables the use of improvisation as performance language, giving birth to a constructive dialogue between video technology and live performance. ‘LFPF’ is a structured environment for exploration of movement through film concepts with the input given by drawings. It enables a live video to develop in front of the audience. It enables the performers to inhabit a truly responsive environment that changes depending on their reaction. It is a twoway dialogue between performers and spatial context powered by a second performer inputting drawings. It also frees the performers from directly having to manipulate any technology and deal with just the artistic result of it. It is therefore a human mediated technological environment. ‘LFPF’ was tested in a series of performances. There are various ways in which Video and Technology are nowadays integrated into Live Performance. It is only natural that the marriage between these elements is going to create an increasingly fluid language for the future. I feel it is essential to think about creating a performance language which supports the ideas of artists, therefore the technology at the service of the artists and never the other way around. That is the idea when I refer to technology in the introduction as a tool for developing creativity.Para realizar a apresentação desta tese será necessário, antes de mais, colocála no seu devido contexto: modelos de interactividade – sistemas, trabalho sistémico, mediação, participação, multimédia, representação digital versus analógica, camadas, tempo físico versus tempo de performance e vídeo, espaço físico versus espaço virtual, material (papel, tinta, etc.) versus projecção de luz e som, tecnologia vestível, e salientar resumidamente quais os artistas que se encontram a desenvolver trabalho relevante na presente área em discussão. Dentro da área da dança em si, já se assiste também à utilização de variadas novas tecnologias e à criação de diferentes contextos. A principal questão que aqui se coloca, é como alcançar uma solução criativa relativa às tecnologias não invasivas para a expressão na dança, e como estabelecer um diálogo entre as diferentes partes, como o desenho, o vídeo, a improvisação na dança, os diálogos interactivos e performativos e o som. Quando fazemos uso do termo “tecnologia não invasiva”, estamos a referirnos concretamente a qualquer tecnologia que não interfira com a integridade física de um dançarino e com a sua capacidade de se mover livremente, tais como cabos, fios ou roupas pesadas, que restrinjam os movimentos em vez de os fazerem fluir. Esta constitui a base do meu projecto: encontrar um quadro de investigação que vá ao encontro desta ideia, assim como encontrar um sistema de ensaio que permita ao dançarino actuar livremente, sem condicionantes ou barreiras físicas. O tema principal de investigação encontrase, como tal, dividido em vários pontos, que irão ser analisados individualmente ao longo da tese, como por exemplo: quando é que surgiu a interacção entre a dança e a tecnologia? O enfoque principal desta investigação é o de tentar casar a tecnologia de vídeo, desenho, som e performance ao vivo do ponto de vista do performer, de forma a melhorar a sua capacidade de interacção com os outros elementos, com total liberdade de movimentos e sem constrições tecnológicas. Este projecto pretende criar uma situação que permita a observação dos performers, explorando e educandose a si mesmos, através da experimentação e do uso de tecnologia aliadas ao movimento. A improvisação é utilizada como uma ferramenta de diálogo, de forma a facilitar a comunicação entre a tecnologia e a performance ao vivo. O ‘LFPF’ propõe desenvolver uma nova abordagem para a relação entre o performer, palco, som e ainda, entre a performance e o seu ambiente/contexto particular. Oferece possibilidades inovadoras sem se tornar intimidante. Uma vez colocado (devidamente configurado), proporciona novas possibilidades de colaboração entre os artistas e uma base comum para que o espectáculo de dança e os artistas plásticos/sonoros possam fundir artes, através da experimentação e do objectivo último: a performance ao vivo. O ‘LFPF’ (Live Film Performance Facilitator) testa e oferece uma nova abordagem à relação entre a performance ao vivo, filme e som, quando combinados em performances ao vivo. Permite a improvisação como linguagem de performance, dando origem a um diálogo constructivo entre a tecnologia de vídeo e a performance ao vivo. O ‘LFPF’ é um ambiente estruturado, destinado à exploração do movimento através da projecção de vídeo, cujo input é fornecido por desenhos. Desta forma é possível desenvolver um vídeo em directo para uma audiência, permitindo que os performers se movam num ambiente verdadeiramente interactivo, que se altera de acordo com a sua reacção. É, portanto, um diálogo nos dois sentidos, entre performers e contexto espacial, complementado por um segundo performer que nos vai apresentando desenhos. Esta dinâmica liberta também os performers de manusearem directamente qualquer tipo de tecnologia, lidando apenas com o respectivo resultado artístico. Tratase assim de um ambiente tecnológico mediado pela acção humana. O ‘LFPF’ já foi testado em vários espectáculos. Hoje em dia, as componentes de vídeo e tecnológica encontramse integradas de várias formas nas performances ao vivo. É, por isso, perfeitamente natural que o casamento entre estes elementos vá criar uma linguagem cada vez mais fluída no futuro. Creio que é fundamental pensar em criar uma linguagem de performance que harmonize as ideias dos artistas, no sentido de colocar a tecnologia ao seu dispor e não o inverso. É este o princípio base que defendo quando, ao longo da introdução, faço referência à tecnologia como uma ferramenta para desenvolver a criatividade

Reframing the Horizon within the Algorithmic Landscape of Northern Britain

Emerging from the artist’s constructed photographs and walking projects in the north, this paper considers the tension between the photograph as a fixed composition of the world and the dynamic image constructed from data. Whereas arguably, the traditional photograph exhibits a stable relationship between the world and the image, the constructed photograph shifts the focus onto the underlying algorithmic processes of production. This focus on the relational nature of the constructed photograph shifts our gaze from the horizon to the underlying systems in operation as we consider the relational nature of data as a photograph