1,181 research outputs found
Algorithms and VLSI architectures for parametric additive synthesis
A parametric additive synthesis approach to sound synthesis is advantageous as it can model sounds in a large scale manner, unlike the classical sinusoidal additive based synthesis paradigms. It is known that a large body of naturally occurring sounds are resonant in character and thus fit the concept well. This thesis is concerned with the computational optimisation of a super class of form ant synthesis which extends the sinusoidal parameters with a spread parameter known as band width. Here a modified formant algorithm is introduced which can be traced back to work done at IRCAM, Paris. When impulse driven, a filter based approach to modelling a formant limits the computational work-load. It is assumed that the filter's coefficients are fixed at initialisation, thus avoiding interpolation which can cause the filter to become chaotic. A filter which is more complex than a second order section is required. Temporal resolution of an impulse generator is achieved by using a two stage polyphase decimator which drives many filterbanks. Each filterbank describes one formant and is composed of sub-elements which allow variation of the formantâs parameters. A resource manager is discussed to overcome the possibility of all sub- banks operating in unison. All filterbanks for one voice are connected in series to the impulse generator and their outputs are summed and scaled accordingly. An explorative study of number systems for DSP algorithms and their architectures is investigated. I invented a new theoretical mechanism for multi-level logic based DSP. Its aims are to reduce the number of transistors and to increase their functionality. A review of synthesis algorithms and VLSI architectures are discussed in a case study between a filter based bit-serial and a CORDIC based sinusoidal generator. They are both of similar size, but the latter is always guaranteed to be stable
Neural network computing using on-chip accelerators
The use of neural networks, machine learning, or artificial intelligence, in its broadest and most controversial sense, has been a tumultuous journey involving three distinct hype cycles and a history dating back to the 1960s. Resurgent, enthusiastic interest in machine learning and its applications bolsters the case for machine learning as a fundamental computational kernel. Furthermore, researchers have demonstrated that machine learning can be utilized as an auxiliary component of applications to enhance or enable new types of computation such as approximate computing or automatic parallelization. In our view, machine learning becomes not the underlying application, but a ubiquitous component of applications. This view necessitates a different approach towards the deployment of machine learning computation that spans not only hardware design of accelerator architectures, but also user and supervisor software to enable the safe, simultaneous use of machine learning accelerator resources.
In this dissertation, we propose a multi-transaction model of neural network computation to meet the needs of future machine learning applications. We demonstrate that this model, encompassing a decoupled backend accelerator for inference and learning from hardware and software for managing neural network transactions can be achieved with low overhead and integrated with a modern RISC-V microprocessor. Our extensions span user and supervisor software and data structures and, coupled with our hardware, enable multiple transactions from different address spaces to execute simultaneously, yet safely. Together, our system demonstrates the utility of a multi-transaction model to increase energy efficiency improvements and improve overall accelerator throughput for machine learning applications
Aircraft noise prediction program theoretical manual: Rotorcraft System Noise Prediction System (ROTONET), part 4
This document describes the theoretical methods used in the rotorcraft noise prediction system (ROTONET), which is a part of the NASA Aircraft Noise Prediction Program (ANOPP). The ANOPP code consists of an executive, database manager, and prediction modules for jet engine, propeller, and rotor noise. The ROTONET subsystem contains modules for the prediction of rotor airloads and performance with momentum theory and prescribed wake aerodynamics, rotor tone noise with compact chordwise and full-surface solutions to the Ffowcs-Williams-Hawkings equations, semiempirical airfoil broadband noise, and turbulence ingestion broadband noise. Flight dynamics, atmosphere propagation, and noise metric calculations are covered in NASA TM-83199, Parts 1, 2, and 3
Holonomic Bessel modules and generating functions
We have solved a number of holonomic PDEs derived from the Bessel modules
which are related to the generating functions of classical Bessel functions and
the difference Bessel functions recently discovered by Bohner and Cuchta. This
-module approach both unifies and extends generating functions of the
classical and the difference Bessel functions. It shows that the algebraic
structures of the Bessel modules and related modules determine the possible
formats of Bessel's generating functions studied in this article. As a
consequence of these -modules structures, a number of new recursion
formulae, integral representations and new difference Bessel polynomials have
been discovered. The key ingredients of our argument involve new transmutation
formulae related to the Bessel modules and the construction of -linear maps
between different appropriately constructed submodules. This work can be viewed
as -module approach to Truesdell's -equation theory specialised to Bessel
functions. The framework presented in this article can be applied to other
special functions.Comment: 97 pages including one blank pag
Designing sound : procedural audio research based on the book by Andy Farnell
In
procedural
media,
data
normally
acquired
by
measuring
something,
commonly
described
as
sampling,
is
replaced
by
a
set
of
computational
rules
(procedure)
that
defines
the
typical
structure
and/or
behaviour
of
that
thing.
Here,
a
general
approach
to
sound
as
a
definable
process,
rather
than
a
recording,
is
developed.
By
analysis
of
their
physical
and
perceptual
qualities,
natural
objects
or
processes
that
produce
sound
are
modelled
by
digital
Sounding
Objects
for
use
in
arts
and
entertainments.
This
Thesis
discusses
different
aspects
of
Procedural
Audio
introducing
several
new
approaches
and
solutions
to
this
emerging
field
of
Sound
Design.Em
Media
Procedimental,
os
dados
os
dados
normalmente
adquiridos
através
da
medição
de
algo
habitualmente
designado
como
amostragem,
sĂŁo
substituĂdos
por
um
conjunto
de
regras
computacionais
(procedimento)
que
definem
a
estrutura
tĂpica,
ou
comportamento,
desse
elemento.
Neste
caso
Ă©
desenvolvida
uma
abordagem
ao
som
definĂvel
como
um
procedimento
em
vez
de
uma
gravação.
Através
da
anĂĄlise
das
suas
caracterĂsticas
fĂsicas
e
perceptuais
,
objetos
naturais
ou
processos
que
produzem
som,
sĂŁo
modelados
como
objetos
sonoros
digitais
para
utilização
nas
Artes
e
Entretenimento.
Nesta
Tese
sĂŁo
discutidos
diferentes
aspectos
de
Ăudio
Procedimental,
sendo
introduzidas
vĂĄrias
novas
abordagens
e
soluçÔes
para
o
campo
emergente
do
Design
Sonoro
Deterministic Artificial Intelligence
Kirchhoffâs laws give a mathematical description of electromechanics. Similarly, translational motion mechanics obey Newtonâs laws, while rotational motion mechanics comply with Eulerâs moment equations, a set of three nonlinear, coupled differential equations. Nonlinearities complicate the mathematical treatment of the seemingly simple action of rotating, and these complications lead to a robust lineage of research culminating here with a text on the ability to make rigid bodies in rotation become self-aware, and even learn. This book is meant for basic scientifically inclined readers commencing with a first chapter on the basics of stochastic artificial intelligence to bridge readers to very advanced topics of deterministic artificial intelligence, espoused in the book with applications to both electromechanics (e.g. the forced van der Pol equation) and also motion mechanics (i.e. Eulerâs moment equations). The reader will learn how to bestow self-awareness and express optimal learning methods for the self-aware object (e.g. robot) that require no tuning and no interaction with humans for autonomous operation. The topics learned from reading this text will prepare students and faculty to investigate interesting problems of mechanics. It is the fondest hope of the editor and authors that readers enjoy the book
Numerical techniques for Fresnel diffraction in computational holography
Optical holography can produce very realistic virtual images due to its capability to properly convey the depth cues that we use to interpret three-dimensional objects. Computational holography is the use of digital representations plus computational methods to carry out the holographic operations of construction and reconstruction. The large computational requirements of holographic simulations prohibit present-day existence of real-time holographic displays comparable in size to traditional two-dimensional displays. Fourier-based approaches to calculate the Fresnel diffraction of light provide one of the most efficient algorithms for holographic computations because this permits the use of the fast Fourier transform (FFT). The limitations on sampling imposed by Fourier-based algorithms have been overcome by the development, in this research, of a fast shifted Fresnel transform. This fast shifted Fresnel transform was used to develop a tiling approach to hologram construction and reconstruction, which computes the Fresnel propagation of light between parallel planes having different resolutions. A new method for hologram construction is presented, named partitioned hologram computation, which applies the concepts of the shifted Fresnel transform and tiling
Digital Signal Processing (Second Edition)
This book provides an account of the mathematical background, computational methods and software engineering associated with digital signal processing. The aim has been to provide the reader with the mathematical methods required for signal analysis which are then used to develop models and algorithms for processing digital signals and finally to encourage the reader to design software solutions for Digital Signal Processing (DSP). In this way, the reader is invited to develop a small DSP library that can then be expanded further with a focus on his/her research interests and applications.
There are of course many excellent books and software systems available on this subject area. However, in many of these publications, the relationship between the mathematical methods associated with signal analysis and the software available for processing data is not always clear. Either the publications concentrate on mathematical aspects that are not focused on practical programming solutions or elaborate on the software development of solutions in terms of working âblack-boxesâ without covering the mathematical background and analysis associated with the design of these software solutions. Thus, this book has been written with the aim of giving the reader a technical overview of the mathematics and software associated with the âartâ of developing numerical algorithms and designing software solutions for DSP, all of which is built on firm mathematical foundations. For this reason, the work is, by necessity, rather lengthy and covers a wide range of subjects compounded in four principal parts. Part I provides the mathematical background for the analysis of signals, Part II considers the computational techniques (principally those associated with linear algebra and the linear eigenvalue problem) required for array processing and associated analysis (error analysis for example). Part III introduces the reader to the essential elements of software engineering using the C programming language, tailored to those features that are used for developing C functions or modules for building a DSP library.
The material associated with parts I, II and III is then used to build up a DSP system by defining a number of âproblemsâ and then addressing the solutions in terms of presenting an appropriate mathematical model, undertaking the necessary analysis, developing an appropriate algorithm and then coding the solution in C. This material forms the basis for part IV of this work.
In most chapters, a series of tutorial problems is given for the reader to attempt with answers provided in Appendix A. These problems include theoretical, computational and programming exercises. Part II of this work is relatively long and arguably contains too much material on the computational methods for linear algebra. However, this material and the complementary material on vector and matrix norms forms the computational basis for many methods of digital signal processing. Moreover, this important and widely researched subject area forms the foundations, not only of digital signal processing and control engineering for example, but also of numerical analysis in general.
The material presented in this book is based on the lecture notes and supplementary material developed by the author for an advanced Masters course âDigital Signal Processingâ which was first established at Cranfield University, Bedford in 1990 and modified when the author moved to De Montfort University, Leicester in 1994. The programmes are still operating at these universities and the material has been used by some 700++ graduates since its establishment and development in the early 1990s. The material was enhanced and developed further when the author moved to the Department of Electronic and Electrical Engineering at Loughborough University in 2003 and now forms part of the Departmentâs post-graduate programmes in Communication Systems Engineering. The original Masters programme included a taught component covering a period of six months based on two semesters, each Semester being composed of four modules. The material in this work covers the first Semester and its four parts reflect the four modules delivered. The material delivered in the second Semester is published as a companion volume to this work entitled Digital Image Processing, Horwood Publishing, 2005 which covers the mathematical modelling of imaging systems and the techniques that have been developed to process and analyse the data such systems provide.
Since the publication of the first edition of this work in 2003, a number of minor changes and some additions have been made. The material on programming and software engineering in Chapters 11 and 12 has been extended. This includes some additions and further solved and supplementary questions which are included throughout the text. Nevertheless, it is worth pointing out, that while every effort has been made by the author and publisher to provide a work that is error free, it is inevitable that typing errors and various âbugsâ will occur. If so, and in particular, if the reader starts to suffer from a lack of comprehension over certain aspects of the material (due to errors or otherwise) then he/she should not assume that there is something wrong with themselves, but with the author
Mixing in incompressible flows: transport, dissipation, and their interplay
In this survey, we address mixing from the point of view of partial differential equations, motivated by applications that arise in fluid dynamics. We give an account of optimal mixing, loss of regularity for transport equations, enhanced dissipation, and anomalous dissipation
- âŠ