Search results for "TTR"
showing 10 items of 3945 documents
Assessing Transfer Entropy in cardiovascular and respiratory time series: A VARFI approach
2021
In the study of complex biomedical systems represented by multivariate stochastic processes, such as the cardiovascular and respiratory systems, an issue of great relevance is the description of the system dynamics spanning multiple temporal scales. Recently, the quantification of multiscale complexity based on linear parametric models, incorporating autoregressive coefficients and fractional integration, encompassing short term dynamics and long-range correlations, was extended to multivariate time series. Within this Vector AutoRegressive Fractionally Integrated (VARFI) framework formalized for Gaussian processes, in this work we propose to estimate the Transfer Entropy, or equivalently G…
Le impressioni dei viaggiatori italiani e stranieri
2011
Il contributo propone la raccolta antologica delle annotazioni più significative che i viaggiatori giunti a Palermo tra l'inizio del Seicento e la prima metà dell’Ottocento hanno lasciato sui Quattro Canti, centro fisico e simbolico della città, nonché snodo obbligatorio per la sua visita.
Damping Provision by Different Virtual Synchronous Machine Schemes
2020
The adoption of virtual synchronous machine (VSM) schemes for the control of power converters is gaining more and more attention both in academia and industry. The VSM control strategies fall into the category of grid-forming converter controls, and they are intended for a range of different applications, providing specific services and different kinds of support to the grid. The paper investigates the possibility of damping provision to the system by VSM power converters. Different schemes are considered and compared, showing the opportunity of the investigated solutions through combined modal and time domain analyses. A specific modification of the power synchronization loop is recognized…
Sensitivity Analysis and Frequency Dynamics of Grid-Connected Converters with Virtual Inertia
2021
For the participation in the frequency control of the system, power converters can be controlled with different strategies and methods, sharing the common concept of virtual inertia capability. In this work, a sensitivity analysis of two main categories of converter controls with virtual inertia is presented. The considered schemes are a grid-following current vector control with additional virtual inertia block and a grid-forming control scheme based on virtual synchronous machine concept. A proper basis for the comparison is first assessed providing an analytical correlation between the control parameters of the two schemes. For the two control strategies, the sensitivity analysis of the …
I diversi volti dell'eutanasia. Prospettive teologiche, etiche e giuridiche a cura di Alessandro Argiroffi, Paolo Becchi, Anna Pia Viola, Daniele ans…
2010
Il libro ha il merito di offrire una panoramica del dibattito in corso su una problematica di grande rilevanza filosofica, teologica e giuridica.
Experimental Validation of Maximum Constant Boost Control and Switching Frequency Optimal for three-phase Quasi-Z-Source Converters
2020
This paper presents a modified modulation scheme for quasi-Z-Source converters, based on the Maximum Constant Boost Control (MCBC) concept and Switching Frequency Optimal (SFO) as reference signal. The effectiveness of the proposed technique is validated by comparing the obtained results (in terms of AC harmonic content and voltage stress) with those carried out from traditional modulation schemes. For this reason, a test bench has been assembled and the benefits of the SFO MCBC modulation scheme have been valuated.
Decoupled control scheme of grid-connected split-source inverters
2017
Grid-connected power conversion systems for renewable energy sources must fulfill several requirements, e.g., the high efficiency, the reduced cost and complexity, and, quite often, the boost capabilities that is usually achieved using a front-end dc–dc boost converter before the inversion stage, leading to a two-stage architecture. Meanwhile, single-stage power conversion systems, which perform the boosting operation within the inversion one, offer some potential advantages, in terms of reducing the complexity and the volume of the whole system. Among several proposed options, the split-source inverter (SSI) has been recently proposed by Abdelhakim et al. as an alternative option with some…
The causal representation of outpatients with Crohn's disease: is there a link between psychological distress and clinical disease activity?
2013
Objectives: Because of the fluctuating and occasional character of Crohn’s disease (CD), patients have to cope with a changeable condition of health. Personal perceived control is known to be an important element of adaptation to their medical condition. The objectives of this work are to determine if perceived personal control is predictive of the clinical activity of the disease and of psychological distress (depression, anxiety). Methods: The Hospital Anxiety Depression Scale (HADS), the causal dimension scale and the Clinical Global Impression (CGI; assessing perceived severity) were administered to 160 patients affected by Crohn’s disease. Indicators of inflammation (CRP), disease dura…
Evaluation of the wave energy density on the Sicilian coast
2016
In this article the wave energy density of the northern Sicilian coasts is evaluated and is used to evaluate the producibility of a wave nergy converter to be installed in an area in the north west part of Sicily. In particular, the objective of the study is the evaluation of a potential installation in an area between Trapani and Palermo, which are the largest cities in the north west part of Sicily. In particular in this research, the wave energy density of Sicily has been analyzed by using an analysis of wave data carried out in a 10-year period, using the measurements of buoyant of National Wave measuring System (RON - Rete Ondametrica Nazionale). The analysis shows that the north-weste…