Least-squares congealing for large numbers of images

In this paper we pursue the task of aligning an ensemble of images in an unsupervised manner. This task has been commonly referred to as “congealing” in literature. A form of congealing, using a least-squares criteria, has been recently demonstrated to have desirable properties over conventional congealing. Least-squares congealing can be viewed as an extension of the Lucas & Kanade (LK)image alignment algorithm. It is well understood that the alignment performance for the LK algorithm, when aligning a single image with another, is theoretically and empirically equivalent for additive and compositional warps. In this paper we: (i) demonstrate that this equivalence does not hold for the extended case of congealing, (ii) characterize the inherent drawbacks associated with least-squares congealing when dealing with large numbers of images, and (iii) propose a novel method for circumventing these limitations through the application of an inverse-compositional strategy that maintains the attractive properties of the original method while being able to handle very large numbers of images.

A least squares based finite volume method for the Cahn-Hilliard and Cahn-Hilliard-reaction equations

A vertex-centred finite volume method (FVM) for the Cahn-Hilliard (CH) and recently proposed Cahn-Hilliard-reaction (CHR) equations is presented. Information at control volume faces is computed using a high-order least-squares approach based on Taylor series approximations. This least-squares problem explicitly includes the variational boundary condition (VBC) that ensures that the discrete equations satisfy all of the boundary conditions. We use this approach to solve the CH and CHR equations in one and two dimensions and show that our scheme satisfies the VBC to at least second order. For the CH equation we show evidence of conservative, gradient stable solutions, however for the CHR equation, strict gradient-stability is more challenging to achieve.

Orthogonality defect and reduced search-space size for solving integer least-squares problems

In the context of ambiguity resolution (AR) of Global Navigation Satellite Systems (GNSS), decorrelation among entries of an ambiguity vector, integer ambiguity search and ambiguity validations are three standard procedures for solving integer least-squares problems. This paper contributes to AR issues from three aspects. Firstly, the orthogonality defect is introduced as a new measure of the performance of ambiguity decorrelation methods, and compared with the decorrelation number and with the condition number which are currently used as the judging criterion to measure the correlation of ambiguity variance-covariance matrix. Numerically, the orthogonality defect demonstrates slightly better performance as a measure of the correlation between decorrelation impact and computational efficiency than the condition number measure. Secondly, the paper examines the relationship of the decorrelation number, the condition number, the orthogonality defect and the size of the ambiguity search space with the ambiguity search candidates and search nodes. The size of the ambiguity search space can be properly estimated if the ambiguity matrix is decorrelated well, which is shown to be a significant parameter in the ambiguity search progress. Thirdly, a new ambiguity resolution scheme is proposed to improve ambiguity search efficiency through the control of the size of the ambiguity search space. The new AR scheme combines the LAMBDA search and validation procedures together, which results in a much smaller size of the search space and higher computational efficiency while retaining the same AR validation outcomes. In fact, the new scheme can deal with the case there are only one candidate, while the existing search methods require at least two candidates. If there are more than one candidate, the new scheme turns to the usual ratio-test procedure. Experimental results indicate that this combined method can indeed improve ambiguity search efficiency for both the single constellation and dual constellations respectively, showing the potential for processing high dimension integer parameters in multi-GNSS environment.

The magic of numbers and the amazing disappearing act : the politics of counting youth homelessness

No-one wants to see young people who are no longer able to stay at home with their parents living in situations that are neither stable nor safe. Most Australians also appreciate that youth homelessness is typically a result of factors beyond the control of young people like poverty, lack of affordable housing, parental divorce or separation, family conflict and violence, sexual abuse, or mental health problems.1 Since the Burdekin Report of 1989 first put the issue on the national agenda, youth homelessness has been a point of some political sensitivity as the numbers of young homeless stayed stubbornly high through the 1990s and into the 2000s.

Uncertainty analysis of pollutant build-up modelling based on a Bayesian Weighted Least Squares approach

Reliable pollutant build-up prediction plays a critical role in the accuracy of urban stormwater quality modelling outcomes. However, water quality data collection is resource demanding compared to streamflow data monitoring, where a greater quantity of data is generally available. Consequently, available water quality data sets span only relatively short time scales unlike water quantity data. Therefore, the ability to take due consideration of the variability associated with pollutant processes and natural phenomena is constrained. This in turn gives rise to uncertainty in the modelling outcomes as research has shown that pollutant loadings on catchment surfaces and rainfall within an area can vary considerably over space and time scales. Therefore, the assessment of model uncertainty is an essential element of informed decision making in urban stormwater management. This paper presents the application of a range of regression approaches such as ordinary least squares regression, weighted least squares Regression and Bayesian Weighted Least Squares Regression for the estimation of uncertainty associated with pollutant build-up prediction using limited data sets. The study outcomes confirmed that the use of ordinary least squares regression with fixed model inputs and limited observational data may not provide realistic estimates. The stochastic nature of the dependent and independent variables need to be taken into consideration in pollutant build-up prediction. It was found that the use of the Bayesian approach along with the Monte Carlo simulation technique provides a powerful tool, which attempts to make the best use of the available knowledge in the prediction and thereby presents a practical solution to counteract the limitations which are otherwise imposed on water quality modelling.

Sensuous geography : the role of sensuous experience and their contemporary implications in public squares, a Lefebvrian approach

This paper explores the sensuous relationship amongst people and the physical elements located in public squares. The research focuses on the study of sensuous geography and its social implications in contemporary city context. Case studies were drawn from various Western countries. A Lefebvrian approach was utilized to analyse the research findings. The study has generated a preliminary sensuous geography checklist for public squares that can predict the degree of popularity and experiential qualities of public squares. However, limits existed in the paper as sensory experiences are conditioned by individual, socio-cultural and climatic influences. The study suggests further integrated approach is needed in this field of study. The research findings indicated that better knowledge of sensuous geography is important in the design and planning disciplines.

Show me the magic : the adventures of Don McAlpine

Synopsis Show Me The Magic takes us on an enthralling and joyful journey into the life and work of the legendary and world-renowned Australian cinematographer, Don McAlpine. A country kid from the small wheat-belt town of Quandialla in isolated south-western New South Wales, Australia, McAlpine was born in 1934 - the year before the first technicolour film was released. There wasn’t even a cinema in Quandialla. Don helped his mother support their family from the age of 14, when his father was stricken by tuberculosis. His part-time job at the Temora chemist as a darkroom photo developer struck a chord in young Don's soul. Soon, a school performance of The Mikado ignited in him the desire to entertain an audience. His fascination with the magical images emerging from his darkroom set him on the winding path that would eventually lead to the glittering lights of Hollywood, where, in 2009, he received the American Society of Cinematographers’ “International Cinematographer of the Year” Award in front of the foremost luminaries of the American film industry. That same year, Don shot his 50th film, X-Men Origins: Wolverine, a big-budget, effects-driven action movie directed by Oscar-winner Gavin Hood and starring Hugh Jackman. Show Me the Magic takes us on set and behind the scenes of that film. In 2011, Don posted another landmark: Mental, a low budget movie directed by PJ Hogan (Muriel’s Wedding, My Best Friend’s Wedding, Peter Pan). Mental was Don’s first digital film and his first Australian film in 25 years. As we travel with Don back into his past, and into the Australian outback landscape that he loves so much, we experience the extremes of movie making: embedded alongside him on the contrasting sets of Wolverine and Mental, we peel back the layers of what Don calls ‘the beautiful deception' of cinema to illuminate the world behind the screen. Joined by celebrated Australian directors Bruce Beresford and Gillian Armstrong, we explore the heritage of the remarkable Australian films that Don photographed, including the iconic Breaker Morant and My Brilliant Career. In Los Angeles, Don reconnects with Paul Mazursky who gave him his big break in Hollywood with Tempest and followed up with Down and Out in Beverly Hills. And two Australians of a later generation - Baz Luhrmann and Catherine Martin - take us behind the scenes on Don’s spectacular creative achievements – Romeo + Juliet and Moulin Rouge! At once the story of a remarkable man and an exploration of filmmaking at the highest level, Show Me The Magic will engage and entrance anyone who has ever been touched by the magic of movies. - See more at: http://www.showmethemagic.com.au/film.htm#synopsis" This film is dedicated to the memory of South African film-maker Peter Henkel, 1924 - 1992.

Abandoning the Magic Circle

As a concept, the magic circle is in reality just 4 years old. Whilst often accredited to Johan Huizinga (1955), the modern usage of term in truth belongs to Katie Salen and Eric Zimmerman. It became in academia following the publication of “Rules of Play” in 2003. Because of the terminologyused, it carries with it unhelpful preconceptions that the game world, or play-space, excludes reality. In this paper, I argue that Salen and Zimmerman (2003) have taken a term used as an example, and applied a meaning to it that was never intended, based primarily upon definitions given by other authors, namely Apter (1991) and Sniderman (n.d.). I further argue that the definition itself contains a logical fallacy, which has prevented the full understanding of the definition in later work. Through a study of the literature in Game Theory, and examples of possible issues which could arise in contemporary games, I suggest that the emotions of the play experience continue beyond the play space, and that emotions from the “real world” enter it with the participants. I consider a reprise of the Stanley Milgram Obedience Experiment (2006), and what that tells us about human emotions and the effect that events taking place in a virtual environment can have upon them. I evaluate the opinion espoused by some authors of there being different magic circles for different players, and assert that this is not a useful approach to take when studying games, because it prevents the analysis of a game as a single entity. Furthermore I consider the reasons given by other authors for the existence of the Magic Circle, and I assert that the term “Magic Circle” should be discarded, that it has no relevance to contemporary games, and indeed it acts as a hindrance to the design and study of games. I conclude that the play space which it claims to protect from the courts and other governmental authorities would be better served by the existing concepts of intent, consent, and commonly accepted principles associated with international travel.

In Pursuit of Magic

In Pursuit of Magic is the next installment in Courtney’s exploration of her position as an artist in the ‘history’ of art in association with notions of infatuation, love and relationships, both real and imagined.

The links between public tendencies and the urban design framework of Brisbane’s public squares: Mapping urban design frameworks present in Brisbane public squares and the correlating activities of the Australian public

This research seeks to demonstrate the ways in which urban design factors, individually and in various well-considered arrangements, stimulate and encourage social activities in Brisbane’s public squares through the mapping and analysis of user behaviour. No design factors contribute to public space in isolation, so the combinations of different design factors, contextual and social impacts as well as local climate are considered to be highly influential to the way in which Brisbane’s public engages with public space. It is this local distinctiveness that this research seeks to ascertain. The research firstly pinpoints and consolidates the design factors identified and recommended in existing literature and then maps the identified factors as they are observed at case study sites in Brisbane. This is then set against observational mappings of the site’s corresponding user activities and engagement. These mappings identify a number of patterns of behaviour; pertinently that “activated” areas of social gathering actively draw people in, and the busier a space is, both the frequency and duration of people lingering in the space increases. The study finds that simply providing respite from the urban environment (and/or weather conditions) does not adequately encourage social interaction and that people friendly design factors can instigate social activities which, if coexisting in a public space, can themselves draw in further users of the space. One of the primary conclusions drawn from these observations is that members of the public in Brisbane are both actively and passively social and often seek out locations where “people-watching” and being around other members of the public (both categorised as passive social activities) are facilitated and encouraged. Spaces that provide respite from the urban environment but that do not sufficiently accommodate social connections and activities are less favourable and are often left abandoned despite their comparable tranquillity and available space.