Calibration approaches for higher order ambisonic microphones

Recent years have seen an increase in the capture and production of ambisonic material due to companies such as YouTube and Facebook utilizing ambisonics for spatial audio playback. Consequently, there is now a greater need for affordable high order microphone arrays due to this uptake in technology. This work details the development of a five-channel circular horizontal ambisonic microphone intended as a tool to explore various optimization techniques, focusing on capsule calibration & pre-processing approaches for unmatched capsules

Takens-Bogdanov bifurcation of travelling wave solutions in pipe flow

The appearance of travelling-wave-type solutions in pipe Poiseuille flow that are disconnected from the basic parabolic profile is numerically studied in detail. We focus on solutions in the 2-fold azimuthally-periodic subspace because of their special stability properties, but relate our findings to other solutions as well. Using time-stepping, an adapted Krylov-Newton method and Arnoldi iteration for the computation and stability analysis of relative equilibria, and a robust pseudo-arclength continuation scheme we unfold a double-zero (Takens-Bogdanov) bifurcating scenario as a function of Reynolds number (Re) and wavenumber (k). This scenario is extended, by the inclusion of higher order terms in the normal form, to account for the appearance of supercritical modulated waves emanating from the upper branch of solutions at a degenerate Hopf bifurcation. These waves are expected to disappear in saddle-loop bifurcations upon collision with lower-branch solutions, thereby leaving stable upper-branch solutions whose subsequent secondary bifurcations could contribute to the formation of the phase space structures that are required for turbulent dynamics at higher Re.Comment: 26 pages, 15 figures (pdf and png). Submitted to J. Fluid Mec

A Computational Procedure to Detect a New Type of High Dimensional Chaotic Saddle and its Application to the 3-D Hill's Problem

A computational procedure that allows the detection of a new type of high-dimensional chaotic saddle in Hamiltonian systems with three degrees of freedom is presented. The chaotic saddle is associated with a so-called normally hyperbolic invariant manifold (NHIM). The procedure allows to compute appropriate homoclinic orbits to the NHIM from which we can infer the existence a chaotic saddle. NHIMs control the phase space transport across an equilibrium point of saddle-centre-...-centre stability type, which is a fundamental mechanism for chemical reactions, capture and escape, scattering, and, more generally, ``transformation'' in many different areas of physics. Consequently, the presented methods and results are of broad interest. The procedure is illustrated for the spatial Hill's problem which is a well known model in celestial mechanics and which gained much interest e.g. in the study of the formation of binaries in the Kuiper belt.Comment: 12 pages, 6 figures, pdflatex, submitted to JPhys

Radiator design system computer programs

Minimum weight space radiator subsystems which can operate over heat load ranges wider than the capabilities of current subsystems are investigated according to projected trends of future long duration space vehicles. Special consideration is given to maximum heat rejection requirements of the low temperature radiators needed for environmental control systems. The set of radiator design programs that have resulted from this investigation are presented in order to provide the analyst with a capability to generate optimum weight radiator panels or sets of panels from practical design considerations, including transient performance. Modifications are also provided for existing programs to improve capability and user convenience

Exploring Musical Expression on the Web: Deforming, Exaggerating, and Blending Decomposed Recordings

We introduce a prototype of an educational web application for comparative performance analysis based on source separation and object-based audio techniques. The underlying system decomposes recordings of classical music performances into note events using score-informed source separation and represents the decomposed material using semantic web technologies. In a visual and interactive way, users can explore individual performances by highlighting specific musical aspects directly within the audio and by altering the temporal characteristics to obtain versions in which the micro-timing is exaggerated or suppressed. Multiple performances of the same work can be compared by juxtaposing and blending between the corresponding recordings. Finally, by adjusting the timing of events, users can generate intermediates of multiple performances to investigate their commonalities and differences

Capsule Calibration Approaches for Low-Cost Higher Order Ambisonic Microphone Arrays

Low-cost electret microphone capsules, such as those accessible to the audio hobbyist or DIY audio electronics community are typically available ‘unmatched’. Ideally one would like to ensure these capsules all reside within a very small production/performance tolerance. In a cost-focused, mass-production environment it is not feasible to measure and match large batches of capsules hence the acoustic performance will differ from capsule to capsule. This paper summarises workaround approaches to capsule calibration in an effort to mitigate/overcome the problems caused by capsule mismatch, with a specific focus on its applications ambisonics and multi-microphone arrays

The Sexual Politics of Clinical Psychoanalysis and Transgender Mental Health

Perversion is derived from the Latin pervertere which means to turn around and has been broadly conceptualized as that which deviates or wavers from an original course. One could argue that the perverse is fundamentally constructed through difference; its existence is predicated upon being set up against some norm and its eccentricity is maintained through a continued refusal to adhere to the rule. This dissertation explores questions of gender difference and sexual deviance as they relate to the clinical pathologization of transgender peoples mental health. In particular, it considers how psychoanalytic theories of perversion - in their multifaceted definitions and various clinical applications - can be usefully employed to understand transphobia as it emerges throughout psychiatric institutions. In borrowing from Freuds polymorphous perversity, fetishism, perverse defense, and Lacans perverse structure, this study both contributes to and moves beyond a genealogical account of transgender peoples relationship to psychoanalysis. It uniquely considers the psychical provocations behind clinicians anxious descriptions and treatments of gender variance, as they have emerged since transsexuals nosological coinage in the early 20th century. By combining two disparate contemporary fields of study - psychoanalysis and transgender studies - this project also asks how transgender people may re-narrate their relationship to the perverse. To do so, this research investigates many under-considered objects of study, including surrealist transsexual drawings from the mid 1900s, lineages of psychiatric taxonomies, science fiction literature, contemporary transgender art installations, autoethno-pornographic transition narratives, and transgender accounts of undergoing psychoanalytic psychotherapy. Through a combination of critical historiographies, discourse analysis, content analysis, and narrative research, this dissertation contributes to a rapidly emerging non-pathological conversation about the psychic life of gender variance, both for transgender people themselves and the mental health institutions that serve them. Ultimately, it finds perversion to be quite useful as a floating signifier, as its various theoretical containers and clinical meanings are employed to deconstruct institutionalized transphobias tenacity. Furthermore, this research centers an archive of historically neglected transgender narratives on mental health as they emerge in the clinic, through case study, and in art or aesthetics. Keywords: transgender, psychoanalysis, mental health, perversion, sexuality, visual ar