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Publicações

Publicações por CTM

2020

TIV.lib: an open-source library for the tonal description of musical audio

Autores
Ramires, A; Bernardes, G; Davies, MEP; Serra, X;

Publicação
CoRR

Abstract
In this paper, we present TIV.lib, an open-source library for the content-based tonal description of musical audio signals. Its main novelty relies on the perceptually-inspired Tonal Interval Vector space based on the Discrete Fourier transform, from which multiple instantaneous and global representations, descriptors and metrics are computed-e.g., harmonic change, dissonance, diatonicity, and musical key. The library is cross-platform, implemented in Python and the graphical programming language Pure Data, and can be used in both online and offline scenarios. Of note is its potential for enhanced Music Information Retrieval, where tonal descriptors sit at the core of numerous methods and applications.

2020

Interfacing sounds: Hierarchical audio content morphologies for creative re-purposing in eargram 2.0

Autores
Bernardes, G;

Publicação
Proceedings of the International Conference on New Interfaces for Musical Expression

Abstract
Audio content-based processing has become a pervasive methodology for techno-fluent musicians. System architectures typically create thumbnail audio descriptions, based on signal processing methods, to visualize, retrieve and transform musical audio efficiently. Towards enhanced usability of these descriptor-based frameworks for the music community, the paper advances a minimal content-based audio description scheme, rooted on primary musical notation attributes at the threefold sound object, meso and macro hierarchies. Multiple perceptually-guided viewpoints from rhythmic, harmonic, timbral and dynamic attributes define a discrete and finite alphabet with minimal formal and subjective assumptions using unsupervised and user-guided methods. The Factor Oracle automaton is then adopted to model and visualize temporal morphology. The generative musical applications enabled by the descriptor-based framework at multiple structural hierarchies are discussed. © 2020, Steering Committee of the International Conference on New Interfaces for Musical Expression. All rights reserved.

2020

Examining Temporal Trends and Design Goals of Digital Music Instruments for Education in NIME: A Proposed Taxonomy

Autores
Margarida Pessoa; Cláudio Parauta; Pedro Luís; Isabela Almeida; Gilberto Bernardes;

Publicação

Abstract
This paper presents an overview of the design principles behind Digital Music Instruments (DMIs) for education across all editions of the International Conference on New Interfaces for Music Expression (NIME). We compiled a comprehensive catalogue of over hundred DMIs with varying degrees of applicability in the educational practice. Each catalogue entry is annotated according to a proposed taxonomy for DMIs for education, rooted in the mechanics of control, mapping and feedback of an interactive music system, along with the required expertise of target user groups and the instrument learning curve. Global statistics unpack underlying trends and design goals across the chronological period of the NIME conference. In recent years, we note a growing number of DMIs targeting non-experts and with reduced requirements in terms of expertise. Stemming from the identified trends, we discuss future challenges in the design of DMIs for education towards enhanced degrees of variation and unpredictability.

2020

Analysis and Design of a Polar Digitally Modulated CMOS PA Based on Switched Constant-Current

Autores
Gomes, R; Duarte, C; Pedro, JC;

Publicação
IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES

Abstract
Typical polar digital power amplifiers (DPAs) employ unit-cells operated in class-E or D-1, denoting a switched-resistance operation which degrades linearity. Besides introducing higher demand on digital predistortion (DPD), it also requires extra quantization bits, impacting the overall efficiency and system complexity. To address this, the present work makes use of an optimized constant-current cascode unit-cell which is combined with reduced conduction angle to achieve linear and efficient operation, while minimizing the effort on DPD and/or calibration. A design strategy is developed which focuses on the cascode bias voltage and transistor relative dimensions as design parameters, allowing cascode efficiency optimization without compromising linearity or reliability. A single-ended polar switched constant-current DPA is implemented in 180-nm standard CMOS. Continuous-wave measurements performed at 800 MHz demonstrate an output power of 24 dBm with a PAE of 47%. The DPA dynamic behavior was tested with a 64-QAM signal with 10 MS/s, achieving an average PAE of 20.9% with a peak-to-average power ratio (PAPR) of 8.7 dB and adjacent-channel leakage ratio (ACLR) = 40.34 dB. These results demonstrate comparable performance with the prior art while using only 6-bits clocked at 100 MHz baseband sampling frequency.

2020

Yield Analysis for Electrical Circuit Designs: Many Problems and Some Recent Developments in Electronic Engineering

Autores
Weber, S; Duarte, C;

Publicação
IEEE Solid-State Circuits Magazine

Abstract
A high production yield, Y = 1 - pfail, and thus a low failure rate, pfail, is a key requirement for successful chip design and the design of many other technical products and systems. We focus on IC design in the analog and mixedsignal domains, where Monte Carlo (MC) techniques have been a standard method for many years (see "Important Monte Carlo Rules Engineers Should Know"). Circuits have to be reliable under certain ranges of environmental parameters, such as supply voltage (V) and temperature (T). Furthermore, the set of semiconductor technology parameters (P) varies significantly, from die to die (global variations) to device to device (local variations, called mismatch). Many circuit tricks are known to minimize all of these influences (for example, using cascodes for a high power-supply rejection, differential pairs to cancel out threshold voltages, special layout techniques, and so on), but at some point problems become hard to anticipate, and further improvements are difficult to achieve. We must accept such variations and need to analyze their impact on production yield, which is a function of these parameters and the specifications (such as design topology and component sizes, among others). © 2009-2012 IEEE.

2020

Can learned frame prediction compete with block motion compensation for video coding?

Autores
Sulun, S; Tekalp, AM;

Publicação
Signal, Image and Video Processing

Abstract

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