Sound mosaics: a graphical user interface for sound synthesis based on audio-visual associations.

This thesis presents the design of a Graphical User Interface (GUI) for computer-based sound synthesis to support users in the externalisation of their musical ideas when interacting with the System in order to create and manipulate sound. The approach taken consisted of three research stages. The first stage was the formulation of a novel visualisation framework to display perceptual dimensions of sound in Visual terms. This framework was based on the findings of existing related studies and a series of empirical investigations of the associations between auditory and visual precepts that we performed for the first time in the area of computer-based sound synthesis. The results of our empirical investigations suggested associations between the colour dimensions of brightness and saturation with the auditory dimensions of pitch and loudness respectively, as well as associations between the multidimensional precepts of visual texture and timbre. The second stage of the research involved the design and implementation of Sound Mosaics, a prototype GUI for sound synthesis based on direct manipulation of visual representations that make use of the visualisation framework developed in the first stage. We followed an iterative design approach that involved the design and evaluation of an initial Sound Mosaics prototype. The insights gained during this first iteration assisted us in revising various aspects of the original design and visualisation framework that led to a revised implementation of Sound Mosaics. The final stage of this research involved an evaluation study of the revised Sound Mosaics prototype that comprised two controlled experiments. First, a comparison experiment with the widely used frequency-domain representations of sound indicated that visual representations created with Sound Mosaics were more comprehensible and intuitive. Comprehensibility was measured as the level of accuracy in a series of sound image association tasks, while intuitiveness was related to subjects' response times and perceived levels of confidence. Second, we conducted a formative evaluation of Sound Mosaics, in which it was exposed to a number of users with and without musical background. Three usability factors were measured: effectiveness, efficiency, and subjective satisfaction. Sound Mosaics was demonstrated to perform satisfactorily in ail three factors for music subjects, although non-music subjects yielded less satisfactory results that can be primarily attributed to the subjects' unfamiliarity with the task of sound synthesis. Overall, our research has set the necessary groundwork for empirically derived and validated associations between auditory and visual dimensions that can be used in the design of cognitively useful GUIs for computer-based sound synthesis and related area

Inhomogeneity driven by Higgs instability in gapless superconductor

The fluctuations of the Higgs and pseudo Nambu-Goldstone fields in the 2SC phase with mismatched pairing are described in the nonlinear realization framework of the gauged Nambu--Jona-Lasinio model. In the gapless 2SC phase, not only Nambu-Goldstone currents can be spontaneously generated, but the Higgs field also exhibits instablity. The Nambu-Goldstone currents generation indicates the formation of the single plane wave LOFF state and breaks rotation symmetry, while the Higgs instability favors spatial inhomogeneity and breaks translation invariance. In this paper, we focus on the Higgs instability which has not drawn much attention yet. The Higgs instability cannot be removed without a long range force, thus it persists in the gapless superfluidity and induces phase separation. In the case of g2SC state, the Higgs instability can only be partially removed by the electric Coulomb energy. However, it is not excluded that the Higgs instability might be completely removed in the charge neutral gCFL phase by the color Coulomb energy.Comment: 21 pages, 5 figure

Thermal Phase Transitions and Gapless Quark Spectra in Quark Matter at High Density

Thermal color superconducting phase transitions in three-flavor quark matter at high baryon density are investigated in the Ginzburg-Landau (GL) approach. We constructed the GL potential near the boundary with a normal phase by taking into account nonzero quark masses, electric charge neutrality, and color charge neutrality. We found that the density of states averaged over paired quarks plays a crucial role in determining the phases near the boundary. By performing a weak coupling calculation of the parameters characterizing the GL potential terms of second order in the pairing gap, we show that three successive second-order phase transitions take place as the temperature increases: a modified color-flavor locked phase (ud, ds, and us pairings) -> a ``dSC'' phase (ud and ds pairings) -> an isoscalar pairing phase (ud pairing) -> a normal phase (no pairing). The Meissner masses of the gluons and the number of gapless quark modes are also studied analytically in each of these phases.Comment: 15 pages, 6 figure

Superpartner Solutions of a BPS Monopole in Noncommutative Space

We construct U(2) BPS monopole superpartner solutions in N=2 non-commutative super Yang-Mills theory. Calculation to the second order in the noncommutative parameter $\theta$ shows that there is no electric quadrupole moment that is expected from the magnetic dipole structure of noncommtative U(2) monopole. This might give an example of the nature of how supersymmetry works not changing between the commutative and noncommutative theories.Comment: 8 page

Gauge Field Fluctuations and First-Order Phase Transition in Color Superconductivity

We study the gauge field fluctuations in dense quark matter and determine the temperature of the induced first-order phase transition to the color-superconducting phase in weak coupling. We find that the local approximation of the coupling between the gauge potential and the order parameter, employed in the Ginzburg-Landau theory, has to be modified by restoring the full momentum dependence of the polarization function of gluons in the superconducting phase.Comment: 5 pages, 1 figure, Revtex, we have modified our conclusions for the metallic superconducto

Co-simulation setup for online model-assisted control design

For reduction of energy intensity of the building sector, effective and parsimonious use of energy resources and climate control systems is a prerequisite. Intelligent Building Energy Management Systems (BEMS) can be key ingredients towards achieving this goal; the incorporation of forecast data into the decision process can help achieve improved performance compared to existing state-of-the-art approaches. In the present paper, the potential of model-based supervisory control design algorithms for automatically designing BEMS is evaluated by performing experiments in a real building. A co-simulation setup is implemented where the thermal simulation model of the building is warmed up using past sensed data and then, given weather and occupancy forecasts, a controller is designed by solving a constrained minimization problem. A stochastic optimization algorithm is used to intelligently search the controller parameter space and identify a controller that minimizes an energy-related cost function, subject to thermal comfort constraints. A middleware solution is deployed in the building to facilitate two-way communication between the building (sensing and actuation) layer and the algorithmic layer

Higgs Mechanism in String Theory

In first-quantized string theory, spacetime symmetries are described by inner automorphisms of the underlying conformal field theory. In this paper we use this approach to illustrate the Higgs effect in string theory. We consider string propagation on M^{24,1} \times S^1, where the circle has radius R, and study SU(2) symmetry breaking as R moves away from its critical value. We find a gauge-covariant equation of motion for the broken-symmetry gauge bosons and the would-be Goldstone bosons. We show that the Goldstone bosons can be eliminated by an appropriate gauge transformation. In this unitary gauge, the Goldstone bosons become the longitudinal components of massive gauge bosons.Comment: 12 pages, Te

Anisotropic Null String Cosmologies

We study string propagation in an anisotropic, cosmological background. We solve the equations of motion and the constraints by performing a perturbative expansion of the string coordinates in powers of c^2, the world-sheet speed of light. To zeroth order the string is approximated by a tensionless string (since c is proportional to the string tension T). We obtain exact, analytical expressions for the zeroth and the first order solutions and we discuss some cosmological implications.Comment: 9 pages, plain Te

Absence of the London limit for the first-order phase transition to a color superconductor

We study the effects of gauge-field fluctuations on the free energy of a homogeneous color superconductor in the color-flavor-locked (CFL) phase. Gluonic fluctuations induce a strong first-order phase transition, in contrast to electronic superconductors where this transition is weakly first order. The critical temperature for this transition is larger than the one corresponding to the diquark pairing instability. The physical reason is that the gluonic Meissner masses suppress long-wavelength fluctuations as compared to the normal conducting phase where gluons are massless, which stabilizes the superconducting phase. In weak coupling, we analytically compute the temperatures associated with the limits of metastability of the normal and superconducting phases, as well as the latent heat associated with the first-order phase transition. We then extrapolate our results to intermediate densities and numerically evaluate the temperature of the fluctuation-induced first-order phase transition, as well as the discontinuity of the diquark condensate at the critical point. We find that the London limit of magnetic interactions is absent in color superconductivity.Comment: 14 pages, 5 figure