Search results for "FREQUENCY"
showing 10 items of 2158 documents
Case study for 3G/UMTS services and billing methods
2001
The 3G/UMTS-networks and services will provide a wide range of telecommunication services. To achieve, this, we need a new view to networks, network services and service abilities. The amount of service providers in the 3G networks will be at least the same than in the present Internet. The amount of users in the 3G networks will overgrow the user amount of Internet forming a global worldwide communication society. This paper discusses customer billing in the 3G world. There are some main issues that are not very, clear to all 3G service and network providers, which however, should be settled before, 3G networks are operational. One of the most important matters is the QoS (Quality of Servi…
Design and optimisation of an innovative two-hub-and-spoke network for the Mediterranean short-sea-shipping market
2020
Abstract Short Sea Shipping (SSS) is generally considered as a privileged transport mode in terms of reducing road congestion and related external costs. In the last two decades, SSS has attracted a lot of attention in the European Union, where it is also regarded as a key factor for economic and social cohesion between countries. In this regard, the present study proposes a new network design that aims at improving and increasing freight traffic between the north-western and the south-eastern shores of the Mediterranean Basin. The proposed model, designed for Ro-Ro (Roll-on Roll-off) freight transport, tries to overcome the limits of the existing multi-port-calling services through an inno…
An RF Wireless Power Transfer system to power battery-free devices for asset tracking
2019
Internet of Things (IoT) and Wireless Sensor Networks (WSN) infrastructures are becoming more and more available and diffused. One major outcome is the development of new services that help to make everyday life easier and better. One of those to which this paper reserves special attention is asset tracking which refers to the method of tracking physical assets. This service is very well based on IoT infrastructure and, due to the enormous number of objects to be traced, desperately needs the availability of inexpensive tags with sensing capabilities, that can be conveniently monitored from a long distance and require no maintenance. For this, engineers are called to face very challenging i…
The effects of different milking intervals and milking times per day in jennet milk production
2012
Abstract In their first 150 days of lactation, nine Ragusana jennets were investigated at the ‘Istituto Sperimentale Zootecnico per la Sicilia’ (ISZS) in Palermo, to study the effects of different milking typologies on milk production. The jennets were kept in a paddock and were fed hay ad libitum and concentrate (3.5 kg jennet/day). From post-foaling day 21, every 3 weeks individual milk amounts were recorded, and individual milk samples were collected and analyzed for the main qualitative parameters. The compared theses were: two daily milking times with 6- and 3-h intervals; and two, three and eight daily milking times with 3-h interval. The jennets were manually milked. The foals were s…
Streams as Seams: Carving trajectories out of the time-frequency matrix
2020
A time-frequency representation of sound is commonly obtained through the Short-Time Fourier Transform. Identifying and extracting the prominent frequency components of the spectrogram is important for sinusoidal modeling and sound processing. Borrowing a known image processing technique, known as seam carving, we propose an algorithm to track and extract the sinusoidal components from the sound spectrogram. Experiments show how this technique is well suited for sound whose prominent frequency components vary both in amplitude and in frequency. Moreover, seam carving naturally produces some auditory continuity effects. We compare this algorithm with two other sine extraction techniques, bas…
Multi-body numerical simulation of the distribution drive system in an internal combustion engine
2008
V clanku je predstaven vyvoj metodiky pro vypocet dynamiky mechanismu motoroveho rozvodu. Vyuzity jsou techniky simulaci vicehmotovych soustav; pouzit byl software AVL/Tycon. Objektem vyzkumu byl vliv pracovnfho rezimu motoru na dynamiku retezoveho rozvodu s jednim (SOHC) a dvema (DOHC) vackovymi hndeli v hiave motoru. Analyza obsahuje dukaz, ze retezovy prevod zavadi (di'ky kinematickemu zaberu) vysokou frekvenci s velmi malou amplitudou v porovnani s harmonickymi frekvencemi od externi sil. Metodika umozhuje urdt zati'zeni vstupni'ho a pomocnych hridelu, zatizeni na strukturu motoru indukovane pres operne a napmaci kladky. Diky tomu se predstavena metodika stava vyznamnym nastrojem pro pr…
NUMERICAL STUDY OF THE PHENOMENON OF “BRAKE SQUEAL” IN THE DISC BRAKES. FIRST RESULTS
2009
In this paper we consider the problem of disc brake noise, an unstable behaviour that occurs in disc brakes due to particular vibratory phenomena. The most obvious phenomenology is the product wheezing during braking. The numerous researches carried out have not yet reached satisfactory results for knowledge. There was a total of high frequency squeal, which depends only on the characteristics of the disc and not by brake complete. Finite element method is applied to achieve modal analysis; a linear model was developed noting that to eliminate or reduce the phenomena of noise brake is necessary that the ranges of calliper-disc frequencies modal do not overlap. The modal analysis of the runw…
CFD PREDICTION OF BUBBLES BEHAVIOUR IN 2-DIMENSIONAL GAS-SOLID FLUIDIZED BEDS
2008
In recent years the use of Computational Fluid Dynamics (CFD) is significantly increasing to simulate multi-phase flows. It is invariably emphasized that a necessary step towards the development of reliable fully predictive CFD models is an extensive experimental validation of the simulation results. This work in particular focuses on the CFD simulation of a lab-scale 2D fluidized bed and the relevant experiments, in order to validate the prediction capability of the used codes and models. It must be emphasized that both experimental and computational quantitative data have been obtained by means of an original Digital Image Analysis Technique, that allows coherent comparison of computation…
Use of Time-Frequency map combined with DBSCAN algorithm for separation of partial discharge pulses under DC voltage
2022
The Phase-Resolved-Partial-Discharge pattern (PRPD) is a conventional technique used for the evaluation of partial discharges (PD) phenomena in High-Voltage-Alternating-Current (HVAC) systems. This map is constructed by plotting the peak of each detected pulses as a function of the phase angle of the supply voltage. Therefore it is obvious that this technique cannot be used for the analysis of data from PD mesaurement under different supply voltage condition (DC). The aim of this paper is to evaluate the application of the Time-Frequency map (TF map) for the analysis of a dataset obtained from PD measurement under DC voltage. A density-based clustering algorithm was also used to gain more i…
A combined CWT-DWT method using model-based design simulator for partial discharges online detection
2009
The suppression of noises is fundamental in onsite Partial Discharge (PD) measurements. For this purpose, the wavelet transform analysis method has been developed and it is a powerful tool for processing the transient and suddenly changing signals. As the wavelet transform possesses the properties of multi-scale analysis and time-frequency domain localization, it is also particularly suitable to process the suddenly changing signals of the partial discharge pulse (PD). In this paper, an improved Wavelet denoising method developed by a model-based design software is presented. Simulations are provided as well as some results obtained during laboratory experiment and on-line PD measurements. …