Search results for " Informatica"

Spectral decomposition of RR-variability obtained by an open loop parametric model for the diagnosis of neuromediate syncope

2002

The role of the cardiovascular regulatory mechanism in patients with neuromediate syncope (NS) is poorly understood. The aim of this study was to accomplish continuous non-invasive analysis of the baroreflex mechanism in patients during a head-tip tilt-table test (HTT) using an open-loop autoregressive model with exogenous input. The model describes the causal dependence of the RR interval on the systolic arterial pressure (SAP) variability. Thus, RR variability results as the linear composition of SAP-dependent (Pdep) and SAP-independent parts of the RR power (P). Further, the model allows the estimation of the baroreflex gain using the modulus of the transfer function (G) from SAP to RR i…

Synchronization index for quantifying nonlinear causal coupling between RR interval and systolic arterial pressure after myocardial infarction

2002

The analysis of nonlinear couplings among cardiovascular variability series can improve the knowledge of the cardioregulatory mechanism and help to understand how it can be affected by pathologies. In this study, the influences of acute myocardial infarction (AMI) on the causal relationships between the heart period and the arterial pressure were investigated by a nonlinear dynamic approach based on the corrected cross-conditional entropy. Whereas the global synchronization index did not differentiate the post-AMI patients from the young and old control groups, the causal indexes evidenced the impairment of the baroreflex control and showed an increase of the mechanical driving of the RR in…

Quantitative assessment of regularity and synchronization of intracardiac recordings during human atrial fibrillation

2003

This study proposes the morphology-based evaluation of the regularity (R) and the synchronization (S) of intra-atrial electrograms acquired during atrial fibrillation (AF). R is defined as the degree of repetitiveness over time of the shapes of the activation waves detected in single atrial recordings. S accounts for the simultaneous presence of morphologically similar activation waves in two atrial electrograms, and for the dispersion of the propagation delays between the two sites. Both R and S resulted unitary for normal sinus rhythm and decreased significantly moving from atrial flutter (R=0.93, S=0.88) to AF of increasing complexity class (type I AF: R=0.75, S=0.66; type II AF: R=0.32,…

Information-Theoretic Analysis of Cardiorespiratory Interactions during Apneic Events in Sleep

2020

In this work, measures of information dynamics are used to describe the dynamics of heart rate and cardiorespiratory interaction associated to sleep breathing disorders. In a large group of patients reporting repeated episodes of hypopneas, apneas (central, obstructive, mixed) and respiratory effort related arousals (RERA), we computed information storage of heart period variability and information transfer from heart period to airflow amplitude before, during and after each event. We find a general tendency to decrease of the information storage, suggesting higher complexity of the cardiac dynamics. The information transfer decreased during apneic events, and increased during milder disord…

Characterisation of the Degree of Musical Non-Markovianity

2022

As an aid for musical analysis, in computational musicology mathematical andinformatics tools have been developed to characterise quantitatively some aspectsof musical compositions. A musical composition can be attributed by ear a certainamount of memory. These results are associated with repetitions and similarities ofthe patterns in musical scores. To higher variations, a lower amount of memory isperceived. However, the musical memory of a score has never been quantitativelydefined. Here we aim to give such a measure following an approach similar tothat used in physics to quantify the memory (non-Markovianity) of open quantumsystems. We apply this measure to some existing musical composit…

ON-LINE CONSTRUCTION OF A SMALL AUTOMATON FOR A FINITE SET OF WORDS

2012

In this paper we describe a "light" algorithm for the on-line construction of a small automaton recognising a finite set of words. The algorithm runs in linear time. We carried out good experimental results on real dictionaries, on biological sequences and on the sets of suffixes (resp. factors) of a set of words that shows how our automaton is near to the minimal one. For the suffixes of a text, we propose a modified construction that leads to an even smaller automaton. We moreover construct linear algorithms for the insertion and deletion of a word in a finite set, directly from the constructed automaton.

Influence on the transient evoked otoacoustic emission by GSM 915 MHz electromagnetic fields: comparative analysis between control and exposed groups

2006

Archaeometric characterization and 3D survey: new perspectives for monitoring and valorization of Morgantina silver Treasure (Sicily)

2015

The Morgantina silver Treasure belonging to the collections of the Archaeological Museum of Aidone (Sicily) were involved in a 3D survey and diagnostics campaign for monitoring over time of the finds, in anticipation of their temporary transfer to the Metropolitan Museum of Art in New York, for a period of four years. According to a multidisciplinary approach, it has been developed a scientific and methodological protocol based on non-invasive techniques to achieve a complete and integrated knowledge of the precious items, of their conservation state and increasing their valorisation. All acquired data, i.e. 3D models, UV fluorescence and X-Ray images and chemical information, will be made …

Mathematics and Musical Entropy

2020

Arts can provide intuitive examples to enhance the understanding of complex mathematical concepts. Also, mathematics can give precise answers to musical questions that can be raised during the analysis of works of art including musical scores. If musical parameters and mathematical objects are seen as belonging to categories, analysis becomes a dialogue and a mapping between them. This paper develops an idea of “open” musicology that exploits suggestions and contaminations with other research areas, first of all from mathematics and the mathematical formalism behind physics. The focus is on the concept of entropy joined with Discrete Fourier Transforms (DFT), that can be extended to the def…

Machine Learning Models for Measuring Syntax Complexity of English Text

2019

In this paper we propose a methodology to assess the syntax complexity of a sentence representing it as sequence of parts-of-speech and comparing Recurrent Neural Networks and Support Vector Machine. We have carried out experiments in English language which are compared with previous results obtained for the Italian one.