The Probability Distribution for Non-Gaussianity Estimators

One of the principle efforts in cosmic microwave background (CMB) research is measurement of the parameter fnl that quantifies the departure from Gaussianity in a large class of non-minimal inflationary (and other) models. Estimators for fnl are composed of a sum of products of the temperatures in three different pixels in the CMB map. Since the number ~Npix^2 of terms in this sum exceeds the number Npix of measurements, these ~Npix^2 terms cannot be statistically independent. Therefore, the central-limit theorem does not necessarily apply, and the probability distribution function (PDF) for the fnl estimator does not necessarily approach a Gaussian distribution for N_pix >> 1. Although the variance of the estimators is known, the significance of a measurement of fnl depends on knowledge of the full shape of its PDF. Here we use Monte Carlo realizations of CMB maps to determine the PDF for two minimum-variance estimators: the standard estimator, constructed under the null hypothesis (fnl=0), and an improved estimator with a smaller variance for |fnl| > 0. While the PDF for the null-hypothesis estimator is very nearly Gaussian when the true value of fnl is zero, the PDF becomes significantly non-Gaussian when |fnl| > 0. In this case we find that the PDF for the null-hypothesis estimator fnl_hat is skewed, with a long non-Gaussian tail at fnl_hat > |fnl| and less probability at fnl_hat < |fnl| than in the Gaussian case. We provide an analytic fit to these PDFs. On the other hand, we find that the PDF for the improved estimator is nearly Gaussian for observationally allowed values of fnl. We discuss briefly the implications for trispectrum (and other higher-order correlation) estimators.Comment: 10 pages, 6 figures, comments welcom

Distortion maps for genus two curves

Distortion maps are a useful tool for pairing based cryptography. Compared with elliptic curves, the case of hyperelliptic curves of genus g > 1 is more complicated since the full torsion subgroup has rank 2g. In this paper we prove that distortion maps always exist for supersingular curves of genus g>1 and we construct distortion maps in genus 2 (for embedding degrees 4,5,6 and 12).Comment: 16 page

Enabling Live Presence: Dynamic Video Compression for the Telematic Arts

Telematic performance, connecting performing artists in different physical locations in a single unified ensemble, places extreme demands on the supporting media. High audio and video quality plays a fundamental role in enabling inter-artist communication and collaboration. However, currently available video solutions are either inadequate to the task or pose extreme technical requirements. A new solution is presented, vipr (videoimage protocol), which exposes a number of popular, robust video compression methods for real-time use in Jitter and Max. This new software has successfully enabled several inter-continental performances and presents exciting potentials for creative, telematic artists, musicians, and dancers

Hand Skates : an apparatus for physically intelligent exercise

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2005.Includes bibliographical references (p. 24).Physical Intelligence refers to the ability of the human organism to smartly and precisely coordinate its internal components and interactions in its environment to solve physically complex tasks. While Physical Intelligence is a key part of physical movement, many pieces of physical fitness equipment fail to challenge or exercise the organism's internal intelligence. Therefore, the goal of this thesis is to design an apparatus that through performing a set of exercises, challenges and develops the body's physical intelligence. Several strategies for developing an apparatus to develop physical intelligence were considered, including an underwater treadmill and an elastic method of providing resistance while running. In the end, however, the strategy developed was the HandSkate, a handheld, low-friction device intended to train core and upper-body muscles by forcing the user to balance themselves and stabilize the HandSkates while performing simple, familiar exercises. Two concepts for the HandSkate were prototyped and tested. The first concept, the 'Boomerang' design, was prototyped from aluminum and consists of a flat, V-shaped base with a cantilevered handle.(cont.) This design is small and comfortable to grip and performs well during exercises that benefit from independent hand movement. The second prototype, the 'T' design, is larger than the first but has several options for hand orientation and allows for a two-handed grip, which allows the user to perform exercises that work best with only one device. Both prototypes easily provide fine motion and provide instability, which challenges the user's physical intelligence while the user exercises. Future improvements include reducing the size of the 'T' design and manufacturing in lighter, less expensive materials.by Benjamin D. Smith.S.B

Musical Deep Learning: Stylistic Melodic Generation with Complexity Based Similarity

The wide-ranging impact of deep learning models implies significant application in music analysis, retrieval, and generation. Initial findings from musical application of a conditional restricted Boltzmann machine (CRBM) show promise towards informing creative computation. Taking advantage of the CRBM’s ability to model temporal dependencies full reconstructions of pieces are achievable given a few starting seed notes. The generation of new material using figuration from the training corpus requires restrictions on the size and memory space of the CRBM, forcing associative rather than perfect recall. Musical analysis and information complexity measures show the musical encoding to be the primary determinant of the nature of the generated results

Big Tent: A Portable Immersive Intermedia Environment

Big Tent, a large scale portable environment for 360 degree immersive video and audio artistic presentation and research, is described and initial experiences are reported. Unlike other fully-surround environments of considerable size, Big Tent may be easily transported and setup in any space with adequate foot print, allowing immersive, interactive content to be brought to non-typical audiences and environments. Construction and implementation of Big Tent focused on maximizing portability by minimizing setup and tear down time, crew requirements, maintenance costs, and transport costs. A variety of different performance and installation events are discussed, exploring the possibilities Big Tent presents to contemporary multi-media artistic creation

Relative Sound Localization for Sources in a Haphazard Speaker Array

A rapidly deployable, easy to use method of automatically configuring multi-channel audio systems is described. Compensating for non-ideal speaker positioning is a problem seen in immersive audio-visual art installations, home theater surround sound setups, and live concerts. Manual configuration requires expertise and time, while automatic methods promise to reduce these costs, enabling quick and easy setup and operation. Ideally the system should outperform a human in aural sound source localization. A naïve method is proposed and paired software is evaluated aiming to cut down on setup time, use readily available hardware, and enable satisfactory multi-channel spatialization and sound-source localization

ArraYnger: New Interface for Interactive 360° Spatialization

Interactive real-time spatialization of audio over large immersive speaker arrays poses significant interface and control challenges for live performers. Fluidly moving and mixing numerous sound objects over unique speaker configurations requires specifically designed software interfaces and systems. Currently available software solutions either impose configuration limitations, require extreme degrees of expertise, or extensive configuration time to use. A new system design, focusing on simplicity, ease of use, and live interactive spatialization is described. Automation of array calibration and tuning is included to facilitate rapid deployment and configuration. Comparisons with other solutions show favorability in terms of complexity, depth of control, and required features

Advancing Expert Human-Computer Interaction Through Music

One of the most important challenges for computing over the next decade is discovering ways to augment and extend human control over ever more powerful, complex, and numerous devices and software systems. New high-dimensional input devices and control systems provide these affordances, but require extensive practice and learning on the part of the user. This paper describes a system created to leverage existing human expertise with a complex, highly dimensional interface, in the form of a trained violinist and violin. A machine listening model is employed to provide the musician and user with direct control over a complex simulation running on a high-performance computing system

Interactive High Performance Computing for Music

The origins of computer music are closely tied to the development of the first high-performance computers associated with major academic and research institutions. These institutions have continued to build extremely powerful computers, now containing thousands of CPUs with incredible processing power. Their precursors were typically designed to operate in non-real time, “batch” mode, and that tradition has remained a dominant paradigm for high performance computing. We describe experimental research in developing the interactive use of a modern high- performance machine, the Abe supercomputer at the National Center for Supercomputing Applications on the University of Illinois at Urbana-Champaign campus, for real-time musical and artistic purposes. We describe the requirements, development, problems, and observations from this project.National Science Foundation, TG-DDM09000