Search results for "Time domain"
showing 10 items of 161 documents
Inter-area oscillations in the 500-kV Vietnamese power system
2019
The paper presents the study of the 500-kV Vietnamese power system. The oscillatory response of the system is analyzed both with a modal analysis and a time domain analysis. The 500-kV system of Vietnam is modeled in details, including all the power plants with the corresponding regulators. The model is developed in collaboration with the Institute of Energy Science IES-VAST of Vietnam and it is validated with the data provided by the National Load Dispatch Centre (NLDC) of Vietnam. The simulation results reveal a clear identification of potential inter-area oscillations between North and South of the Country. A worsening of the observed phenomenon should be considered as possible, especial…
Bearing fault detection based on time-frequency representations of vibration signals
2015
To prevent failures of a rolling bearing in the gearbox drive system, acceleration sensors are used to detect fault-related signals of the bearing. It is a big challenge to observe and identify signals caused by bearing defects in the time domain or the frequency spectrum by a conventional Fourier analysis. The time-frequency representation of the fault-related signals implemented by the windowed Fourier transform is studied in this work. It is shown that the fault characteristic frequencies can be clearly identified in the time-frequency spectrum if a fault occurs in the bearing of the gearbox at different speeds. Otherwise, the shaft frequency and its multiples are the main harmonics in t…
Reliability and validity of time domain heart rate variability during daily rout¡ne activities : an alternative to the morning orthostatic test?
2017
Summary Study aim: To determine the reliability and validity of a time domain heart rate variability (HRV) index during free-living physical activity (FLPA). Material and methods: Eight white-collar workers participated in this study. RR intervals (time between consecutive R-peaks of the PQRS complex) were recorded using the Polar V800 heart rate (HR) monitor upon awakening and at work on 16 different days. A total of 127 cycles of sitting periods followed by walking breaks were included for consecutive pairwise analysis for reliability. The HR values from the orthostatic test (OT) were compared with the corresponding values at work. Results: The HR values showed high levels of repeatabilit…
Exact Reconstruction of Sub-wavelength THz Source Profile via Combination of Knife-edge Technique and Time-domain Spectroscopy
2013
Brevi note a margine di Cassazione 23 marzo 2017 n. 7551 in tema di sdemanializzazione tacita
2017
La sentenza della Cassazione 23 marzo 2017 n. 7551 ribadisce il principio che la natura demaniale marittima di un terreno non può essere esclusa se non in forza di un provvedimento amministrativo. Non può pertanto il giudice sostituirsi all’amministrazione in tale valutazione discrezionale. The judgment of the Supreme Court (n° 7551/2017) reiterates the principle according to which the public maritime nature of an area can not be excluded except by virtue of an administrative decision. Therefore, the judge can not substitute the administration for this discretionary assessment.
Rotational effects on the oscillation frequencies of newly born proto-neutron stars
2003
In this paper we study the effects of rotation on the frequencies of the quasi-normal modes of a proto-neutron star (PNS) born in a gravitational collapse during the first minute of life. Our analysis starts a few tenths of seconds after the PNS formation, when the stellar evolution can be described by a sequence of equilibrium configurations. We use the evolutionary models developed by Pons et al. (1999; 2001) that describe how a non rotating star cools down and contracts while neutrino diffusion and thermalization processes dominate the stellar dynamics. For assigned values of the evolution time, we set the star into slow rotation and integrate the equations of stellar perturbations in th…
Fault diagnosis of induction motors broken rotor bars by pattern recognition based on noise cancelation
2014
Current signal monitoring (CSM) can be used as an effective tool for diagnosing broken rotor bars fault in induction motors. In this paper, fault diagnosis and classification based on artificial neural networks (ANNs) is done in two stages. In the first stage, a filter is designed to remove irrelevant fault components (such as noise) of current signals. The coefficients of the filter are obtained by least square (LS) algorithm. Then by extracting suitable time domain features from filter's output, a neural network is trained for fault classification. The output vector of this network is represented in one of four categories that includes healthy mode, a 5 mm crack on a bar, one broken bar, …
Exploiting ongoing EEG with multilinear partial least squares during free-listening to music
2016
During real-world experiences, determining the stimulus-relevant brain activity is excitingly attractive and is very challenging, particularly in electroencephalography. Here, spectrograms of ongoing electroencephalogram (EEG) of one participant constructed a third-order tensor with three factors of time, frequency and space; and the stimulus data consisting of acoustical features derived from the naturalistic and continuous music formulated a matrix with two factors of time and the number of features. Thus, the multilinear partial least squares (PLS) conforming to the canonical polyadic (CP) model was performed on the tensor and the matrix for decomposing the ongoing EEG. Consequently, we …
End-users Co-create Shared Information for a More Complete Real-time Maritime Picture
2017
European Union Member States are working towards an integrated maritime surveillance and deeper information sharing and implementation of Common Information Sharing Environment. Value networks aiming at co-creation, need active facilitation, and relevant platforms for open cooperation. This study analysed scenario analytics, and narrative documents from projects CoopP, CISE, and MARISA by using a Data Extraction Table to classify both objects and phenomenon relevant to European maritime information sharing systems. The object and phenomenon rows are grouped under a European Coast Guard Functions, CGFs framework, to better understand their occurrence and interdependencies. This paper finds t…