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Nowadays, under controlled conditions the speaker verification systems based on the GMM-UBM paradigm show very good performance. However, in forensic investigation activities the conditions; in which recordings are acquired; are uncontrollable, a naive use of the baseline GMM-UBM system without feature normalization, model transformation and score normalization techniques yields to unreliable forensic...
Digital audio equalization is used to enhance the listening experience introducing corrections in the auditory frequency response. The equalizer performance depends on its implementation which includes optimal filters with sharp transition bandwidth development and a low computational complexity. Starting from a previous FIR implementation based on multirate systems and filterbanks theory, an optimized...
We propose a method of double linear correlation, which enables simultaneous calculation of the linear correlation between a sequence and a template and of the linear correlation between the sequence and the reversed template. Using the symmetric property of the discrete cosine transform (DCT) basis, we need to neither expand sequences symmetrically nor reverse the template. Proper zero-padding in...
Discussion on the reference signal (RS) and the related parameters in the recently proposed Cross Wigner-Ville distribution (XWVD) based method for the signal components instantaneous frequency (IF) estimation is presented. By a convenient choice of the reference signal, cross-terms are formed in such a way that the XWVD between the analyzed signal (AS) and a reference signal (RS) yields a scaled...
In the L-estimation and compressive sensing some arbitrarily positioned samples of the signal are either so heavily corrupted by disturbances that it is better to omit them in the analysis or they are unavailable. If the considered signal with missing samples is sparse then we are still able to reconstruct these samples by using the well know reconstruction algorithms. In this paper we will illustrate...
The class of lattice wave digital (LWD) filters, which are constructed as a parallel connection of two all-pass branches, is extended beyond the known lowpass, highpass, bandpass, and bandstop designs. The goal is to generate a generic design procedure for LWD filters having an arbitrary number of interlaced passbands and stopbands such that such that in each passband and stopband the magnitude criteria...
The analog filters are usually converted to IIR digital filters using appropriate transformation of system function from s-domain to z-domain. Recently another approach of converting an analog filter described by a diagram or a netlist to a digital filter has been proposed. Using this Analog Filter Netlist to Digital Filter Statements (AFN-DFS) approach, one can use a previous implementation in analog...
Recent advances in developing Brain-Computer Interfaces (BCIs) have opened up a new realm for designing efficient systems that could enable disabled people to communicate. The P300 speller is one important BCI application that allows the selection of characters on a virtual keyboard by analyzing recorded electroencephalography (EEG) activity. In this work, we propose an ensemble classifier that uses...
In many fields, non-preemptive real-time scheduling of a set of periodic tasks with different release times is very important if not even necessary. The number and characteristics of tasks may vary during time, thus imposing to re-evaluate the task schedulability over time. In this paper we propose an efficient sufficient schedulability condition, and we analytically show that if this bound is satisfied,...
Due to their local regularity properties, well logs are successfully modeled using multifractional Brownian motions. These local fractal processes provide a consistent framework to explore regularity of the logs, measured by the Hölder exponent (H), at all depths in the logged interval. This paper presents the results of a regularity analysis carried out on datasets recorded in three Algerian oil...
The scale invariant third order moment, skewness, is analysed as an objective function to an adaptive gradient ascent algorithm. The purpose is to achieve a spectrum at the filter output that can enable identification of possible bearing defect signatures which are impulsive and periodic. Harmonically related sinusoids are used to represent such signatures and to build a signal model allowing characterization...
The paper presents an improved version of Asynchronous Sigma-Delta Modulator (ASDM) in order to reduce its power consumption for time-encoding of analog signals. The proposed method is called Amplitude Adaptive ASDM (AA-ASDM) since time-varying envelope of the signal is used in the feedback loop of ASDM to reduce the switching rate of the output trigger. Regardless of this reduction the perfect recovery...
Finding the largest code with a given minimum distance is one of the most basic problems in coding theory. In this paper, we compute new upper bounds on size of codes in the Lee metric using the linear programming method. We present a recursive formula for obtaining the Lee-numbers, which makes it possible to efficiently compute these bounds. The obtained bounds are useful in determining whether good...
In this paper we are presenting a method for achieving strain analysis of cardiac tissues from 3D ultrasound images. First of all, the left ventricle was segmented by an iterative snake algorithm which exploits the gradient vector flow field estimated from the 3D images. Once the ventricle was segmented, a set of points located on the external surface of the ventricle was selected. The movement of...
High dynamic range displays based on dual panel LCD are a viable option for building a low-cost solution for providing high bit depth visualization systems. One of the factors limiting the usability of this type of displays are the computation requirements of the algorithm necessary for correct visualization using the two stacked panels. In this work we present the methodology and the results of mapping...
Previous studies on stereoscopic acuity have shown that the percentage of stereo blind subjects is relevant. Therefore, there is the need of performing a stereo blindness and stereo acuity test before each visualization session involving stereoscopic images. In this paper we propose a computer based test suitable for a generic stereo displays, with the aim of testing different visual parameters to...
The DICOM Grayscale Standard Display Function (GSDF) is widely used in the medical imaging field to map the image values into luminance emitted by the display. However, the DICOM GSDF is not accurate at very dark luminance levels, and this causes a loss of visibility in the details if an image is viewed on the novel High Dynamic Rance display devices such as the ones based on the Dual Layer LCD technology...
The objective of this study was to test the feasibility of using wearable sensors and wireless technology to measure the autonomic function and stress level in the ambulatory setting. Autonomic function was studied acquiring ECG tracings by means of a wearable sensorized chest strap. Galvanic skin response (GSR) was measured as an indicator of stress level by two electrodes positioned on the palm...
The purpose of this study is to develop a novel segmentation approach for saccular aneurysm extraction using computed tomography angiography (CTA). Manual segmentation is a tedious procedure, not precise and prone to inter- and intra-observer variability. Therefore, there is a need for an automated method, which is accurate, reproducible and reliable. The approach consists of four stages. At the first...
There is increased interest in the visualization community to experiment the benefit of HDR presentation. Current developments in HDR displays are geared towards projecting more realistic images than conventional (non-HDR) displays. The dynamic range of the natural world is approximately 14 orders of magnitude while conventional displays are limited to at most 3 orders of magnitude in luminance. A...
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