Swinging the Score: Compositional and empirical investigations into the performance of swing and groove rhythms by score-reading musicians

This PhD project consists of (1) an empirical thesis and (2) a portfolio of compositions with commentary. 1.) The thesis explores the effect of habitually playing from music notation on classical musicians’ ability to play by ear and produce the jazz phrasing structure known as “swing”. Swing and its relationship to groove are explored from musicological and psychological perspectives, focussing especially on its conflicting relationship with notation when performed by classical musicians. Two behavioural studies explore interactions between classical musicians’ notation reading, aural discrimination skills, and their swing performance. One of these also allows for formulating a syntax definition of swing, which so far is lacking in the literature. The first study investigates levels of score-dependency, i.e. dependency on notational over aural learning, in classical musicians. Results of several aural reproduction tasks show that score-dependent musicians are more limited in aural reproduction of pitch than score-independent musicians, though no difference between groups is found for rhythmic reproduction. Score-dependency is found to be a likely consequence of long-term task specialisation that can be mitigated by engaging in practices involving playing by ear. The second study focuses on how classical musicians produce swing while playing from notation, as evaluated by jazz-enculturated listeners. In line with the first study, results suggest that performers’ score-dependency has little bearing on their perceived swing rhythm. Instead it modulates the relationship between notational style and swing, with score-dependent musicians swinging more using classical and jazz notation formats. Unlike in jazz practice, listening to jazz recordings did not improve classical musicians’ swing. Jazz listeners’ detailed critiques of classical musicians’ swing provided details for formulating a syntax definition of swing: Swing is a particular cultural expression of groove, characterised by both synchronization and de-synchronization from a near- metronomic beat sequence, an unequal beat subdivision, rhythmic displacement, offbeat articulation, and a preference for faster tempi. The results presented in this thesis have wider implications for research on behavioural and microrhythmic issues in swing and groove production, cognition in aural vs. notation-based music learning, and effects of musical experiences on performance practice. 2.) The portfolio of compositions demonstrates the practical application of swing and groove rhythms in notation for artistic purposes. Over the course of four pieces, it explores how such rhythms can be negotiated in a variety of contexts, including semi-improvised vs. fully scripted performances, classical vs. crossover orchestrations, and metric ambiguities vs. steady rhythmic frameworks. Together, the portfolio and thesis contribute to both creative and empirical research on intercultural composition and associated notation practices

Stability and statistical inferences in the space of topological spatial relationships

Modelling topological properties of the spatial relationship between objects, known as the extit{topological relationship}, represents a fundamental research problem in many domains including Artificial Intelligence (AI) and Geographical Information Science (GIS). Real world data is generally finite and exhibits uncertainty. Therefore, when attempting to model topological relationships from such data it is useful to do so in a manner which is both extit{stable} and facilitates extit{statistical inferences}. Current models of the topological relationships do not exhibit either of these properties. We propose a novel model of topological relationships between objects in the Euclidean plane which encodes topological information regarding connected components and holes. Specifically, a representation of the persistent homology, known as a persistence scale space, is used. This representation forms a Banach space that is stable and, as a consequence of the fact that it obeys the strong law of large numbers and the central limit theorem, facilitates statistical inferences. The utility of this model is demonstrated through a number of experiments

Spatio-temporal modeling of the topology of swarm behavior with persistence landscapes

We propose a method for modeling the topology of swarm behavior in a manner which facilitates the application of machine learning techniques such as clustering. This is achieved by modeling the persistence of topological features, such as connected components and holes, of the swarm with respect to time using zig-zag persistent homology. The output of this model is subsequently transformed into a representation known as a persistence landscape. This representation forms a vector space and therefore facilitates the application of machine learning techniques. The proposed model is validated using a real data set corresponding to a swarm of 300 fish. We demonstrate that it may be used to perform clustering of swarm behavior with respect to topological features

Modelling topological features of swarm behaviour in space and time with persistence landscapes

This paper presents a model of swarm behaviour that encodes the spatial-temporal characteristics of topological features such as holes and connected components. Specifically, the persistence of topological features with respect to time are computed using zig-zag persistent homology. This information is in turn modelled as a persistence landscape which forms a normed vector space and facilitates the application of statistical and data mining techniques. Validation of the proposed model is performed using a real data set corresponding to a swarm of fish. It is demonstrated that the proposed model may be used to perform retrieval and clustering of swarm behaviour in terms of topological features. In fact, it is discovered that clustering returns clusters corresponding to the swarm behaviours of flock, torus and disordered. These are the most frequently occurring types of behaviour exhibited by swarms in general

3-D SPH simulations of colliding winds in eta Carinae

We study colliding winds in the superluminous binary eta Carinae by performing three-dimensional, Smoothed Particle Hydrodynamics (SPH) simulations. For simplicity, we assume both winds to be isothermal. We also assume that wind particles coast without any net external forces. We find that the lower density, faster wind from the secondary carves out a spiral cavity in the higher density, slower wind from the primary. Because of the phase-dependent orbital motion, the cavity is very thin on the periastron side, whereas it occupies a large volume on the apastron side. The model X-ray light curve using the simulated density structure fits very well with the observed light curve for a viewing angle of i=54 degrees and phi=36 degrees, where i is the inclination angle and phi is the azimuth from apastron.Comment: 6 pages, 3 figures, To be published in Proceedings of IAU Symposium 250: Massive Stars as Cosmic Engines, held in Kauai, Hawaii, USA, Dec 2007, edited by F. Bresolin, P.A. Crowther & J. Puls (Cambridge University Press

Exact Level And Power Of Permutation, Bootstrap, And Asymptotic Tests Of Trend

We develop computational tools that can evaluate the exact size and power of three tests of trend (e.g., permutation, bootstrap and asymptotic) without resorting to large-sample theory or simulations. We then use these tools to compare the operating characteristics of the three tests. It is seen that the bootstrap test is ultra-conservative relative to the other two tests and as a result suffers from a severe deterioration in power. The power of the asymptotic test is uniformly larger than that of the other two tests, but it fails to preserve the Type I error for most of the range of the baseline response probability. The permutation test, being exact, is guaranteed to preserve the Type I error throughout the range of the baseline response probability. The price paid for this guarantee is a loss of power relative to the asymptotic test. The power loss is, however, small in most situations

X-ray Modeling of \eta\ Carinae and WR140 from SPH Simulations

The colliding wind binary (CWB) systems \eta\ Carinae and WR140 provide unique laboratories for X-ray astrophysics. Their wind-wind collisions produce hard X-rays that have been monitored extensively by several X-ray telescopes, including RXTE. To interpret these RXTE X-ray light curves, we model the wind-wind collision using 3D smoothed particle hydrodynamics (SPH) simulations. Adiabatic simulations that account for the absorption of X-rays from an assumed point source at the apex of the wind-collision shock cone by the distorted winds can closely match the observed 2-10keV RXTE light curves of both \eta\ Car and WR140. This point-source model can also explain the early recovery of \eta\ Car's X-ray light curve from the 2009.0 minimum by a factor of 2-4 reduction in the mass loss rate of \eta\ Car. Our more recent models relax the point-source approximation and account for the spatially extended emission along the wind-wind interaction shock front. For WR140, the computed X-ray light curve again matches the RXTE observations quite well. But for \eta\ Car, a hot, post-periastron bubble leads to an emission level that does not match the extended X-ray minimum observed by RXTE. Initial results from incorporating radiative cooling and radiatively-driven wind acceleration via a new anti-gravity approach into the SPH code are also discussed.Comment: 5 pages, 3 figures, Proceedings of the 39th Li\'ege Astrophysical Colloquium, held in Li\`ege 12-16 July 2010, edited by G. Rauw, M. De Becker, Y. Naz\'e, J.-M. Vreux, P. William

High-Energy Astrophysics in the 2020s and Beyond

With each passing decade, we gain new appreciation for the dynamic, connected, and often violent nature of the Universe. This reality necessarily places the study of high-energy processes at the very heart of modern astrophysics. This White Paper illustrates the central role of high-energy astrophysics to some of the most pressing astrophysical problems of our time, the formation/evolution of galaxies, the origin of the heavy elements, star and planet formation, the emergence of life on exoplanets, and the search for new physics. We also highlight the new connections that are growing between astrophysicists and plasma physicists. We end with a discussion of the challenges that must be addressed to realize the potential of these connections, including the need for integrated planning across physics and astronomy programs in multiple agencies, and the need to foster the creativity and career aspirations of individual scientists in this era of large projects.Comment: Astro2020 White Paper submissio