184 research outputs found
Towards automatic extraction of harmony information from music signals
PhDIn this thesis we address the subject of automatic extraction of harmony
information from audio recordings. We focus on chord symbol recognition
and methods for evaluating algorithms designed to perform that task.
We present a novel six-dimensional model for equal tempered pitch
space based on concepts from neo-Riemannian music theory. This model
is employed as the basis of a harmonic change detection function which
we use to improve the performance of a chord recognition algorithm.
We develop a machine readable text syntax for chord symbols and
present a hand labelled chord transcription collection of 180 Beatles songs
annotated using this syntax. This collection has been made publicly available
and is already widely used for evaluation purposes in the research
community. We also introduce methods for comparing chord symbols
which we subsequently use for analysing the statistics of the transcription
collection. To ensure that researchers are able to use our transcriptions
with confidence, we demonstrate a novel alignment algorithm based on
simple audio fingerprints that allows local copies of the Beatles audio files
to be accurately aligned to our transcriptions automatically.
Evaluation methods for chord symbol recall and segmentation measures
are discussed in detail and we use our chord comparison techniques
as the basis for a novel dictionary-based chord symbol recall calculation.
At the end of the thesis, we evaluate the performance of fifteen chord
recognition algorithms (three of our own and twelve entrants to the 2009
MIREX chord detection evaluation) on the Beatles collection. Results
are presented for several different evaluation measures using a range of
evaluation parameters. The algorithms are compared with each other in
terms of performance but we also pay special attention to analysing and
discussing the benefits and drawbacks of the different evaluation methods
that are used
Ultracold atoms in multiple-radiofrequency dressed adiabatic potentials
We present the first experimental demonstration of a multiple-radiofrequency
dressed potential for the configurable magnetic confinement of ultracold atoms.
We load cold Rb atoms into a double well potential with an adjustable
barrier height, formed by three radiofrequencies applied to atoms in a static
quadrupole magnetic field. Our multiple-radiofrequency approach gives precise
control over the double well characteristics, including the depth of individual
wells and the height of the barrier, and enables reliable transfer of atoms
between the available trapping geometries. We have characterised the
multiple-radiofrequency dressed system using radiofrequency spectroscopy,
finding good agreement with the eigenvalues numerically calculated using
Floquet theory. This method creates trapping potentials that can be
reconfigured by changing the amplitudes, polarizations and frequencies of the
applied dressing fields, and easily extended with additional dressing
frequencies.Comment: 16 pages, 6 figure
The Semantic Web MIDI Tape: An Interface for Interlinking MIDI and Context Metadata
The Linked Data paradigm has been used to publish a large number of musical datasets and ontologies on the Semantic Web, such as MusicBrainz, AcousticBrainz, and the Music Ontology. Recently, the MIDI Linked Data Cloud has been added to these datasets, representing more than 300,000 pieces in MIDI format as Linked Data, opening up the possibility for linking fine-grained symbolic music representations to existing music metadata databases. Despite the dataset making MIDI resources available in Web data standard formats such as RDF and SPARQL, the important issue of finding meaningful links between these MIDI resources and relevant contextual metadata in other datasets remains. A fundamental barrier for the provision and generation of such links is the difficulty that users have at adding new MIDI performance data and metadata to the platform. In this paper, we propose the Semantic Web MIDI Tape, a set of tools and associated interface for interacting with the MIDI Linked Data Cloud by enabling users to record, enrich, and retrieve MIDI performance data and related metadata in native Web data standards. The goal of such interactions is to find meaningful links between published MIDI resources and their relevant contextual metadata. We evaluate the Semantic Web MIDI Tape in various use cases involving user-contributed content, MIDI similarity querying, and entity recognition methods, and discuss their potential for finding links between MIDI resources and metadata
Probing multiple-frequency atom-photon interactions with ultracold atoms
We dress atoms with multiple-radiofrequency fields and investigate the
spectrum of transitions driven by an additional probe field. A complete
theoretical description of this rich spectrum is presented, in which we find
allowed transitions and determine their amplitudes using the resolvent
formalism. Experimentally, we observe transitions up to sixth order in the
probe field using radiofrequency spectroscopy of Bose-Einstein condensates
trapped in single- and multiple-radiofrequency-dressed potentials. We find
excellent agreement between theory and experiment, including the prediction and
verification of previously unobserved transitions, even in the
single-radiofrequency case.Comment: 20 pages, 7 figure
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Age Structure Metrics for Precautionary Management: Can Simpler Assessment Techniques Save Fish, Time, and Money?
Stock assessment techniques currently used in the United States are extremely costly to implement, involve significant data requirements, and are inaccessible to all but a few stock assessment scientists. A systematic decrease in fishery yields and the designation of several species as overfished on the west coast of the United States have resulted in stricter protocols regarding sustainable fisheries management and the rebuilding of overfished stocks, including the need to set annual harvest limits for all exploited species. An alternative and simpler approach to stock assessment which could address this need is described and an evaluation framework set up. Although no results have been obtained to date, possible costs and benefits of incorporating this approach into fisheries management are discussed
Evidence for a curvilinear relationship between sympathetic nervous system activation and women’s physiological sexual arousal
Abstract There is increasing evidence that women's physiological sexual arousal is facilitated by moderate sympathetic nervous system (SNS) activation. Literature also suggests that the level of SNS activation may play a role in the degree to which SNS activity affects sexual arousal. We provide the first empirical examination of a possible curvilinear relationship between SNS activity and women's genital arousal using a direct measure of SNS activation in 52 sexually functional women. The relationship between heart rate variability (HRV), a specific and sensitive marker of SNS activation, and vaginal pulse amplitude (VPA), a measure of genital arousal, was analyzed. Moderate increases in SNS activity were associated with higher genital arousal, while very low or very high SNS activation was associated with lower genital arousal. These findings imply that there is an optimal level of SNS activation for women's physiological sexual arousal
The Effect of Iron on Dislocation Evolution in Model and Commercial Zirconium Alloys
Although the evolution of irradiation-induced dislocation loops has been well correlated with irradiation-induced growth phenomena, the effect of alloying elements on this evolution remains elusive, especially at low fluences. To develop a more mechanistic understanding of the role iron has on loop formation, we used state-of-the-art techniques to study a proton-irradiated Zr-0.1Fe alloy and proton- and neutron-irradiated Zircaloy-2. The two alloys were irradiated with 2-MeV protons up to 7 dpa at 350\ub0C and Zircaloy-2 up to 14.7
7 1025n • m-2, approximately 24 dpa, in a boiling water reactor at approximately 300\ub0C. Baseline transmission electron microscopy showed that the Zr3Fe secondary-phase particles in the binary system were larger and fewer in number than the Zr (Fe, Cr)2and Zr2(Fe, Ni) particles in Zircaloy-2. An analysis of the irradiated binary alloy revealed only limited dissolution of Ze3Fe, suggesting little dispersion of iron into the matrix, while at the same time a higher 〈a〉-loop density was observed compared with Zircaloy-2 at equivalent proton dose levels. We also found that the redistribution of iron during irradiation led to the formation of iron nanoclusters. A delay in the onset of 〈c〉-loop nucleation in proton-irradiated Zircaloy-2 compared with the binary alloy was observed. The effect of iron redistributed from secondary-phase particles because of dissolution on the density and morphology of 〈a〉 and 〈c〉 loops is described. The implication this may have on irradiation-induced growth of zirconium fuel cladding is also discussed
Achieving the impossible : A review of magic-based interventions and their effects on wellbeing
Research has demonstrated that involvement with mainstream performing arts, such as music and dance, can boost wellbeing. This article extends this work by reviewing little-known research on whether learning magic tricks can have an equally beneficial effect. We first present an historic overview of several magic-based interventions created by magicians, psychologists and occupational therapists. We then identify the potential benefits of such interventions, and review studies that have attempted to systematically assess these interventions. The studies have mostly revealed beneficial outcomes, but much of the work is of poor methodological quality (involving small numbers of participants and no control group), and has tended to focus on clinical populations. Finally, we present guidelines for future research in the area, emphasizing the need for more systematic and better-controlled studies.Peer reviewe
Maternal Immune Activation Induces Adolescent Cognitive Deficits Preceded by Developmental Perturbations in Cortical Reelin Signalling.
Exposure to maternal immune activation (MIA) in utero significantly elevates the risk of developing schizophrenia and other neurodevelopmental disorders. To understand the biological mechanisms underlying the link between MIA and increased risk, preclinical animal models have focussed on specific signalling pathways in the brain that mediate symptoms associated with neurodevelopmental disorders such as cognitive dysfunction. Reelin signalling in multiple brain regions is involved in neuronal migration, synaptic plasticity and long-term potentiation, and has been implicated in cognitive deficits. However, how regulation of Reelin expression is affected by MIA across cortical development and associated cognitive functions remains largely unclear. Using a MIA rat model, here we demonstrate cognitive deficits in adolescent object-location memory in MIA offspring and reductions in Reln expression prenatally and in the adult prefrontal cortex. Further, developmental disturbances in gene/protein expression and DNA methylation of downstream signalling components occurred subsequent to MIA-induced Reelin dysregulation and prior to cognitive deficits. We propose that MIA-induced dysregulation of Reelin signalling contributes to the emergence of prefrontal cortex-mediated cognitive deficits through altered NMDA receptor function, resulting in inefficient long-term potentiation. Our data suggest a developmental window during which attenuation of Reelin signalling may provide a possible therapeutic target
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