Petre G. Pop

On the speaker verification using the TESPAR coding method

This work describes study on the speaker verification rate, using the TESPAR (Time Encoding Signal Processing and Recognition) coding method, when the speech signal is sampled at different rates. The effect of filtering on the speech signal was studied, as well. The TESPAR method is a processing and recognition method in the time domain, proposed by R.A. King. The key problem is to define the TESPAR alphabet used for the TESPAR coding process. In this paper is proposed an approach to generate this alphabet using the Kohonen Neural Networks in a vector quantization process. For the recognition process parallel Multi Layer Perceptron (MLP) neural network were used. As inputs for training/test vectors of the MLP-NN, the TESPAR-S matrices were employed.

DNA repeats detection using BW spectrograms

The presence of repeated sequences is a fundamental feature of genomes and detection of repeats is important in biology and medicine as it can be used for phylogenic studies and disease diagnosis. A major difficulty in identification of repeats arises from the fact that the repeat units can be either exact or imperfect, in tandem or dispersed, and of unspecified length. This paper presents results obtained by combining BW spectrograms with a novel numerical representation to isolate position and length of tandem repeats (TRs) in DNA sequences.

Tandem Repeats Localization Using Spectral Techniques

The detection of tandem repeats is important in biology and medicine as it can be used for phylogenic studies and disease diagnosis. A major difficulty in identification of repeats arises from the fact that the repeat units can be either exact or imperfect, in tandem or dispersed, and of unspecified length. This paper presents results obtained with a modified product spectrum and BW spectrograms to isolate position and length of tandem repeats (TRs) in DNA sequences.

Spectral Techniques In Finding DNA Approximate Tandem Repeats

The detection of tandem repeats is important in biology and medicine as it can be used for phylogenic studies and disease diagnosis. This paper presents results obtained with spectral techniques using Fourier analysis for detecting approximate tandem repeats (ATRs) in DNA sequences. These methods are sensitive to ATRs and are robust in the presence of substitutions, insertions, and deletions

In-memory dedicated dot-plot analysis for DNA repeats detection

DNA repeats are believed to play significant roles in genome evolution and manifestation of severe diseases. Many of the methods for finding repeated sequences use distances, similarities and consensus sequences to generate candidate sequences. This paper presents results obtained using a dedicated numerical representation with a mapping algorithm (using DNA distances and consensus types) and an in-memory dot-plot analysis combined with image processing techniques, to visual isolate the positions of DNA repeats with different lengths.

DNA repeats detection using a dedicated dot-plot analysis

DNA repeats are believed to play significant roles in genome evolution and diseases. Many of the methods for finding repeated sequences are part of the digital signal processing (DSP) field and most of these methods use distances, similarities and consensus sequences to generate candidate sequences. This paper presents results obtained using a dedicated numerical representation with a mapping algorithm (using DNA distances and consensus types) and a custom dot-plot analysis (using similarities to represent DNA patterns) combined with image processing techniques, to isolate the position of DNA patterns with different lengths.

A visual tool for DNA repeats screening

DNA sequence analysis has been developing to reveal some hidden structure, to distinguish coding from noncoding regions in DNA sequence, and to explore structural similarity among DNA sequences. DNA repeats are associated with human disease, seems to play a role in genome organization and evolution and are important in regulatory processes. A lot of the methods for finding repeated sequences use signal processing techniques which implies distances, similarities and consensus sequences to generate candidate sequences. This paper presents results obtained using a mapping algorithm and a custom dot-plot analysis combined with image processing techniques, to isolate the position of DNA patterns with different lengths.

Bias field inhomogeneity measurements

Magnetic resonance imaging (MRI) is affected by intensity inhomogeneity where the illuminated areas alternate with shadow areas. The phenomenon of inhomogeneity is barely noticeable by the human observer, but in the field of automated image segmentation or registration, the unwanted intensity variations can cause significant errors. An important step in image processing is the evaluation of the inhomogeneity and the adequate correction of this artifact. In this paper we have proposed to measure the inhomogeneity with the most well-known quantitative formulas. We shall also put forward two new measurement methods: one for direct measurement and one for indirect measurement. The first method measures the smoothness of the bias field ratio, regardless the used correction algorithm. The second defines a procedure and an image function for inhomogeneity evaluation. The values obtained point the inhomogeneity level out and suppress the white noise better than the usual algorithms. We used simulated MR images obtained from the Brain Web site in the quantitative and comparative evaluations. The results obtained, when compared to existing methods, show a significant confidence level for the proposed measurements.

Distances and numerical similarities in DNA repeats detection

Many of the methods for detecting repeated sequences are part of the digital signal processing (DSP) field and most of these methods use distances, similarities and consensus sequences to generate candidate sequences. This paper presents results obtained using a dedicated numerical representation and a mapping algorithm (with different DNA distances and consensus types) and a custom dot-plot analysis (with different similarities to represent DNA patterns) to isolate the position of DNA repeats with specific lengths.

DNA motifs detection algorithms in long sequences

The identification of DNA motifs remains an active challenge for the researchers in the bioinformatics domain. A considerable effort in this area was concentrated on understanding the evolution of the genome by identifying the DNA binding sites for transcription factors. The evolution in genome sequencing has led to the appearance of numerous computational methods for finding the short DNA segments, known as motifs. In this study, we present some of the computational methods that exist and try to evaluate their performance in case of long sequences.