Sample-level sound synthesis with recurrent neural networks and conceptors

Conceptors are a recent development in the field of reservoir computing; they can be used to influence the dynamics of recurrent neural networks (RNNs), enabling generation of arbitrary patterns based on training data. Conceptors allow interpolation and extrapolation between patterns, and also provide a system of boolean logic for combining patterns together. Generation and manipulation of arbitrary patterns using conceptors has significant potential as a sound synthesis method for applications in computer music but has yet to be explored. Conceptors are untested with the generation of multi-timbre audio patterns, and little testing has been done on scalability to longer patterns required for audio. A novel method of sound synthesis based on conceptors is introduced. Conceptular Synthesis is based on granular synthesis; sets of conceptors are trained to recall varying patterns from a single RNN, then a runtime mechanism switches between them, generating short patterns which are recombined into a longer sound. The quality of sound resynthesis using this technique is experimentally evaluated. Conceptor models are shown to resynthesise audio with a comparable quality to a close equivalent technique using echo state networks with stored patterns and output feedback. Conceptor models are also shown to excel in their malleability and potential for creative sound manipulation, in comparison to echo state network models which tend to fail when the same manipulations are applied. Examples are given demonstrating creative sonic possibilities, by exploiting conceptor pattern morphing, boolean conceptor logic and manipulation of RNN dynamics. Limitations of conceptor models are revealed with regards to reproduction quality, and pragmatic limitations are also shown, where rises in computation and memory requirements preclude the use of these models for training with longer sound samples. The techniques presented here represent an initial exploration of the sound synthesis potential of conceptors, demonstrating possible creative applications in sound design; future possibilities and research questions are outlined

Effect of exercise and of meals of differing starch content on glucose kinetics and muscle glycogen utilization and replenishment in horses

A combination of plasma and muscle biochemical methods, indirect calorimetry, isotopic tracer studies ([6,6-2H]glucose as constant rate infusion) and real-time reverse transcription polymerase chain reaction techniques were used to gain a better understanding of the effect of ingestion of meals of differing starch content prior to or after exercise by horses. In the first study (Chapter 3), horses were fed before exercise either (1) corn, (2) an isocaloric amount of alfalfa cubes (51.4 KJ/kg DE), or (3) not fed. The main finding was that meal type prior to exercise modestly altered substrate use during exercise such that corn feeding resulted in greater carbohydrate oxidation due to higher skeletal muscle utilization of blood-borne glucose, unchanged muscle glycogenolysis and lower whole body lipid oxidation. In the second study (Chapter 4), the glycemic response to ingestion of cereals (cracked corn, steamed oat groats or rolled barley) and intragastric administration of glucose was assessed by giving equal amounts of hydrolyzable carbohydrates. We determined that oat groats, corn and barley have similar areas under the plasma glucose concentration time curve in horses, and compared with the glycemic index of 100, these cereals were approximately 60. In the third study (Chapter 5), horses with exercise-induced muscle glycogen depletion were either not fed for 8 h, fed mixed alfalfa and grass hay (~15 Mcal, ~62 MJ DE), or fed an isocaloric amount of corn immediately and 4 h after exercise. The main findings were that corn feeding, when compared to feed withholding, resulted in mild to moderate hyperglycemia and hyperinsulinemia, and a 3-fold greater whole body availability and utilization of glucose. However, muscle glycogen replenishment was only minimally enhanced. In the last study (Chapter 6), we described the effect of glycogen-depleting exercise and of meal type after exercise (as in Chapter 5) on the insulin responsive glucose transporter (GLUT4) gene expression in skeletal muscle. We found that GLUT 4 gene expression in muscle increased by ~2-4 fold during 24 h after exercise, when compared to that prior to exercise but no differences were observed due to meal type fed after exercise

Effect of exercise and of meals of differing starch content on glucose kinetics and muscle glycogen utilization and replenishment in horses

A combination of plasma and muscle biochemical methods, indirect calorimetry, isotopic tracer studies ([6,6-2H]glucose as constant rate infusion) and real-time reverse transcription polymerase chain reaction techniques were used to gain a better understanding of the effect of ingestion of meals of differing starch content prior to or after exercise by horses. In the first study (Chapter 3), horses were fed before exercise either (1) corn, (2) an isocaloric amount of alfalfa cubes (51.4 KJ/kg DE), or (3) not fed. The main finding was that meal type prior to exercise modestly altered substrate use during exercise such that corn feeding resulted in greater carbohydrate oxidation due to higher skeletal muscle utilization of blood-borne glucose, unchanged muscle glycogenolysis and lower whole body lipid oxidation. In the second study (Chapter 4), the glycemic response to ingestion of cereals (cracked corn, steamed oat groats or rolled barley) and intragastric administration of glucose was assessed by giving equal amounts of hydrolyzable carbohydrates. We determined that oat groats, corn and barley have similar areas under the plasma glucose concentration time curve in horses, and compared with the glycemic index of 100, these cereals were approximately 60. In the third study (Chapter 5), horses with exercise-induced muscle glycogen depletion were either not fed for 8 h, fed mixed alfalfa and grass hay (~15 Mcal, ~62 MJ DE), or fed an isocaloric amount of corn immediately and 4 h after exercise. The main findings were that corn feeding, when compared to feed withholding, resulted in mild to moderate hyperglycemia and hyperinsulinemia, and a 3-fold greater whole body availability and utilization of glucose. However, muscle glycogen replenishment was only minimally enhanced. In the last study (Chapter 6), we described the effect of glycogen-depleting exercise and of meal type after exercise (as in Chapter 5) on the insulin responsive glucose transporter (GLUT4) gene expression in skeletal muscle. We found that GLUT 4 gene expression in muscle increased by ~2-4 fold during 24 h after exercise, when compared to that prior to exercise but no differences were observed due to meal type fed after exercise

The synthesis of sound with application in a MIDI environment

The wide range of options for experimentation with the synthesis of sound are usually expensive, difficult to obtain, or limit the experimenter. The work described in this thesis shows how the IBM PC and software can be combined to provide a suitable platform for experimentation with different synthesis techniques. This platform is based on the PC, the Musical Instrument Digital Interface (MIDI) and a musical instrument called a digital sampler. The fundamental concepts of sound are described, with reference to digital sound reproduction. A number of synthesis techniques are described. These are evaluated according to the criteria of generality, efficiency and control. The techniques discussed are additive synthesis, frequency modulation synthesis, subtractive synthesis, granular synthesis, resynthesis, wavetable synthesis, and sampling. Spiral synthesis, physical modelling, waveshaping and spectral interpolation are discussed briefly. The Musical Instrument Digital Interface is a standard method of connecting digital musical instruments together. It is the MIDI standard and equipment conforming to that standard that makes this implementation of synthesis techniques possible. As a demonstration of the PC platform, additive synthesis, frequency modulation synthesis, granular synthesis and spiral synthesis have been implemented in software. A PC equipped with a MIDI interface card is used to perform the synthesis. The MIDI protocol is used to transmit the resultant sound to a digital sampler. The INMOS transputer is used as an accelerator, as the calculation of a waveform using software is a computational intensive process. It is concluded that sound synthesis can be performed successfully using a PC and the appropriate software, and utilizing the facilities provided by a MIDI environment including a digital sampler

Carbohydrate metabolism in exercising horses

Carbohydrate and fat are the predominant sources of energy during exercise in mammals. Carbohydrates, such as muscle glycogen and plasma glucose, and fats from adipose tissue and intramuscular triglycerides are oxidized during exercise in amounts and proportions that vary depending on the exercise intensity, level of fitness and nutritional status. In horses, muscle glycogen, and to a lesser extent plasma glucose, are oxidized in substantial amounts during low-, moderate- and high-intensity exercise. Carbohydrate availability to skeletal muscle affects exercise performance in humans, however this relationship is not well outlined in horses. Glucose supplementation by intravenous administration during exercise in horses increases duration of moderate intensity exercise. However, the effect of glucose supplementation by ingestion of a soluble carbohydrate-rich meal prior to exercise on athletic performance has not been established in horses. Low muscle glycogen concentrations prior to exercise in horses are associated with decreased time to exhaustion at moderate- and high-intensity exercise. Nutritional interventions intended to enhance muscle glycogen resynthesis have proved less successful in horses than in other species. Replenishment of muscle glycogen after strenuous exercise in horses is not complete until 48-72 h after exercise, whereas in humans and laboratory animals it is complete by 24 h. The slower rate of muscle glycogen replenishment after exercise in horses may be related to an inherent lower ability to digest starch and other sources of glucose, a lower ability to synthesize muscle glycogen, or both. The aim of this review is to describe the present understanding of carbohydrate metabolism in the exercising horse, its implications on nutrition and athletic performance, and to contrast it with that in other species

Non-Standard Sound Synthesis with Dynamic Models

Full version unavailable due to 3rd party copyright restrictions.This Thesis proposes three main objectives: (i) to provide the concept of a new generalized non-standard synthesis model that would provide the framework for incorporating other non-standard synthesis approaches; (ii) to explore dynamic sound modeling through the application of new non-standard synthesis techniques and procedures; and (iii) to experiment with dynamic sound synthesis for the creation of novel sound objects. In order to achieve these objectives, this Thesis introduces a new paradigm for non-standard synthesis that is based in the algorithmic assemblage of minute wave segments to form sound waveforms. This paradigm is called Extended Waveform Segment Synthesis (EWSS) and incorporates a hierarchy of algorithmic models for the generation of microsound structures. The concepts of EWSS are illustrated with the development and presentation of a novel non-standard synthesis system, the Dynamic Waveform Segment Synthesis (DWSS). DWSS features and combines a variety of algorithmic models for direct synthesis generation: list generation and permutation, tendency masks, trigonometric functions, stochastic functions, chaotic functions and grammars. The core mechanism of DWSS is based in an extended application of Cellular Automata. The potential of the synthetic capabilities of DWSS is explored in a series of Case Studies where a number of sound object were generated revealing (i) the capabilities of the system to generate sound morphologies belonging to other non-standard synthesis approaches and, (ii) the capabilities of the system of generating novel sound objects with dynamic morphologies. The introduction of EWSS and DWSS is preceded by an extensive and critical overview on the concepts of microsound synthesis, algorithmic composition, the two cultures of computer music, the heretical approach in composition, non- standard synthesis and sonic emergence along with the thorough examination of algorithmic models and their application in sound synthesis and electroacoustic composition. This Thesis also proposes (i) a new definition for “algorithmic composition”, (ii) the term “totalistic algorithmic composition”, and (iii) four discrete aspects of non-standard synthesis

Interpretive electronic music systems: a portfolio of compositions

A portfolio of electronic music compositions employing adaptable controllers, graphic notation, and custom software performance environments. The portfolio is comprised of scores, recordings, and supporting software and audio files for the following: Short Circuit; Sample & Hold; Mute | Solo; NCTRN; Radio | Silence; and Please use the tramps provided. Supplementary files include alternative audio and video recordings of some of the works listed above, additional software documentation, and a video recording of a structured improvisation featuring the controllers and software used in this portfolio

Analysis and resynthesis of polyphonic music

This thesis examines applications of Digital Signal Processing to the analysis, transformation, and resynthesis of musical audio. First I give an overview of the human perception of music. I then examine in detail the requirements for a system that can analyse, transcribe, process, and resynthesise monaural polyphonic music. I then describe and compare the possible hardware and software platforms. After this I describe a prototype hybrid system that attempts to carry out these tasks using a method based on additive synthesis. Next I present results from its application to a variety of musical examples, and critically assess its performance and limitations. I then address these issues in the design of a second system based on Gabor wavelets. I conclude by summarising the research and outlining suggestions for future developments

The Effect of Forage Quality on Voluntary Hay Intake, Serum Glucose and Insulin, Muscle Glycogen, Whole Blood Lactate, Heart Rate, and Respiratory Parameters of Exercised Horses

Six mares and six geldings were used to determine the effect of forage quality on muscle glycogen utilization by exercised horses. Horses were fed 1.5% BW/d of high quality (65.6% NDF; 41.1% ADF) or low quality (74.6% NDF; 51.2% ADF) hay and a concentrate resulting in three diets: high quality hay and concentrate balanced to meet energy requirements (HQ); low quality hay and concentrate balanced to meet energy requirements; and low quality hay with the same amount of concentrate as the HQ diet. The effect of hay quality on serum insulin, serum glucose, whole blood lactate, and respiratory parameters were also determined. Results suggested varied metabolic responses to exercise between sexes and a possible glycogen sparing effect when low quality forage was consumed

Singing voice resynthesis using concatenative-based techniques

Tese de Doutoramento. Engenharia Informática. Faculdade de Engenharia. Universidade do Porto. 201