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Publications

Publications by CTM

2011

REFLECT: Rendering FPGAs to Multi-core Embedded Computing

Authors
Cardoso, JMP; Diniz, PC; Petrov, Z; Bertels, K; Hübner, M; van Someren, H; Gonçalves, F; de Coutinho, JGF; Constantinides, GA; Olivier, B; Luk, W; Becker, J; Kuzmanov, G; Thoma, F; Braun, L; Kühnle, M; Nane, R; Sima, VM; Krátký, K; Alves, JC; Ferreira, JC;

Publication
Reconfigurable Computing

Abstract

2011

Concatenative singing voice resynthesis

Authors
Fonseca, N; Ferreira, A; Rocha, AP;

Publication
17th DSP 2011 International Conference on Digital Signal Processing, Proceedings

Abstract
The concept of capturing the sound of something for later replication is not new, and it is used in many synthesizers. But capturing sounds and use them as an audio effect, is less common. This paper presents an approach for the resynthesis of a singing voice, based on concatenative techniques, that uses pre-recorded audio material as an high level semantic audio effect, replacing an original audio recording with the sound of a different singer, while trying to keep the same musical/phonetic performance. © 2011 IEEE.

2011

Estimation of harmonic and noise components of the glottal excitation

Authors
Sousa, R; Ferreira, A; Alku, P;

Publication
Models and Analysis of Vocal Emissions for Biomedical Applications - 7th International Workshop, MAVEBA 2011

Abstract
This paper describes an algorithm which enables harmonic and noise splitting of the glottal excitation of voiced speech. The algorithm utilizes a straightforward harmonic and noise splitter which is utilized prior to glottal inverse filtering. The results show improved estimates of the glottal excitation in comparison to a known inverse filtering method.

2011

Singing Voice Analysis Using Relative Harmonic Delays

Authors
Sousa, R; Ferreira, A;

Publication
12TH ANNUAL CONFERENCE OF THE INTERNATIONAL SPEECH COMMUNICATION ASSOCIATION 2011 (INTERSPEECH 2011), VOLS 1-5

Abstract
In this paper we introduce new phase-related features denoting the delay between the harmonics and the fundamental frequency of a periodic signal, notably of voiced singing. These features are identified as Normalized Relative Delay (NRD) and denote the phase contribution to the shape invariance of a periodic signal. Thus, NRDs are amenable to a physical and psychophysical interpretation and are structurally independent of the overall time shift of the signal, an important property that is shared with the magnitude spectrum in the case of a locally stationary signal. We describe the NRD and report on preliminary studies testing the discrimination capability of NRDs applied to singing signals.

2011

Fast prototyping of network protocols through ns-3 simulation model reuse

Authors
Carneiro, G; Fontes, H; Ricardo, M;

Publication
SIMULATION MODELLING PRACTICE AND THEORY

Abstract
In the networking research and development field, one recurring problem faced is the duplication of effort to write first simulation and then implementation code. We posit an alternative development process that takes advantage of the built in network emulation features of Network Simulator 3 (ns-3) and allows developers to share most code between simulation and implementation of a protocol. Tests show that ns-3 can handle a data plane processing large packets, but has difficulties with small packets. When using ns-3 for implementing the control plane of a protocol, we found that ns-3 can even outperform a dedicated implementation.

2011

On performance of group key distribution techniques when applied to IPTV services

Authors
Pinto, A; Ricardo, M;

Publication
COMPUTER COMMUNICATIONS

Abstract
IPTV services consist of multiple video channels grouped in bundles, such as sports, movies or generic bundles; users typically subscribe multiple bundles, including the generic bundle. Secure IP multicast can be used to implement IPTV services, but it still has problems to be addressed. Current solutions require high computational power in video channel zapping situations, lack support for groups sourced at the users, and present a weak support for admission control in IP multicast for both sources and receivers in dynamically configured environments. This work proposes a new, secure and efficient IPTV solution that, cumulatively: (a) enforces individual access control to groups of real-time IPTV video channels; (b) enforces IP multicast admission control for both multicast senders and receivers; (c) supports user generated videos; (d) generates low signaling overheads; (e) does not introduce perceivable delays, particularly in video channel zapping situations. Moreover, this solution can be easily integrated in the IPTV architectures being developed by ETSI and ITU-T.

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