2012
Authors
Barczy, M; Ispany, M; Pap, G; Scotto, M; Silva, ME;
Publication
STATISTICAL PAPERS
Abstract
In this paper the integer-valued autoregressive model of order one, contaminated with additive outliers is studied in some detail. Moreover, parameter estimation is also addressed. Supposing that the timepoints of the outliers are known but their sizes are unknown, we prove that the conditional least squares (CLS) estimators of the offspring and innovation means are strongly consistent. In contrast, however, the CLS estimators of the outliers' sizes are not strongly consistent, although they converge to a random limit with probability 1. We also prove that the joint CLS estimator of the offspring and innovation means is asymptotically normal. Conditionally on the values of the process at the timepoints neighboring to the outliers' occurrences, the joint CLS estimator of the sizes of the outliers is also asymptotically normal.
2011
Authors
Soiisa, R; Ferreira, A;
Publication
Proceedings of the AES International Conference
Abstract
In this paper we focus on the real-time frequency domain analysis of speech signals, and on the extraction of suitable and perceptually meaningful features that are related to the glottal source and that may pave the way for robust speaker identification and voice register classification. We take advantage of an analysis-synthesis framework derived from an audio coding algorithm in order to estimate and model the relative delays between the different harmonics reflecting the contribution of the glottal source and the group delay of the vocal tract filter. We show in this paper that this approach effectively captures the shape invariance of a periodic signal and may be suited to monitor and extract in real-time perceptually important features correlating well with specific voice registers or with a speaker unique sound signature. A first validation study is described that confirms the competitive performance of the proposed approach in the automatic classification of the breathy, normal and pressed voice phonation types.
2011
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
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
Authors
Brás, L; Jorge, AM; Gomes, EF; Duarte, R;
Publication
Technology and Medical Sciences - TMSi 2010
Abstract
We are developing a new method for the identification of rib boundaries in chest x-ray images. The identification of rib boundaries is important for radiologist diagnosis of lung diseases as TB. The radiologists use the ribs as reference for location and can be used to eliminate false positives in the detection of abnormalities. Our method automatically identifies rib boundaries from raw images through a sequence of steps using a combination of image processing techniques. Radiographs are still very relevant in practice because in Portugal and many other countries it is the first step for TB detection. We have access a large database of x-ray images provided by the pneumological screening centre (CDP) of Vila Nova de Gaia, in Portugal.
2011
Authors
Bras, L; Jorge, AM; Gomes, EF; Duarte, R;
Publication
TECHNOLOGY AND MEDICAL SCIENCES - TMSI 2010
Abstract
We are developing a new method for the identification of rib boundaries in chest x-ray images. The identification of rib boundaries is important for radiologist diagnosis of lung diseases as TB. The radiologists use the ribs as reference for location and can be used to eliminate false positives in the detection of abnormalities. Our method automatically identifies rib boundaries from raw images through a sequence of steps using a combination of image processing techniques. Radiographs are still very relevant in practice because in Portugal and many other countries it is the first step for TB detection. We have access a large database of x-ray images provided by the pneumological screening centre (CDP) of Vila Nova de Gaia, in Portugal.
The access to the final selection minute is only available to applicants.
Please check the confirmation e-mail of your application to obtain the access code.