Search results for "Telecommunication"

2020

The growth of cloud-based services is mainly supported by the core networking infrastructures of large-scale data centers, while the scalability of these services is influenced by the performance and dependability characteristics of data centers. Hence, the data center network must be agile and reconfigurable in order to respond quickly to the ever-changing application demands and service requirements. The network must also be able to interconnect the big number of nodes, and provide an efficient and fault-tolerant routing service to upper-layer applications. In response to these challenges, the research community began exploring novel interconnect topologies, namely: Flecube, DCell, Ficonn…

A study on the use of bare buried conductors in an extended interconnection of earthing systems inside a MV network

2005

In the field of electrical safety an important topic is the transmission of voltages, during an earth fault, inside an extended interconnection of local earthing systems. The paper presents a study, with reference to the MV networks, about those systems where the interconnection between the earth electrodes of the electrical installations is carried out using bare buried conductors. Starting from the description of the circuital model of a bare buried conductor interconnecting together the earth electrodes of two MV/lv substations, the mathematical model of the whole interconnected earthing system is found. Finally, the results of some simulations, giving the distribution of the fault curre…

Analysis of the new submarine interconnection system between Italy and Malta: Simulation of transmission network operation

2016

In this paper, some simulations of the interconnected Sicilian and Maltese transmission systems are performed, in order to assess this new system configuration. The HVAC submarine interconnection between Italy and Malta came into operation in 2015 and is part of a European programme for transmission grid interconnection improvement. This new line has been built in order to allow a better management of the power system of both the islands. Firstly, a brief description of the interconnection system is given. Moreover, the transmission systems of Sicily and Malta are depicted and their structures are shown. The simulations are carried out by means of a model of the interconnected system create…

Analysis of different Sleeve Ferrite Cores Performance according to their Dimensions

2019

Sleeve ferrite core is an EMI suppressor widely used to reduce the conductive and radiated electromagnetic noise in cables. The interconnection of different electronic systems through cables is becoming more difficult due to the hard restrictions related to EMC compliance requirements. Thereby, the research of new solutions able to provide a great attenuation ratio in a wide frequency band is a challenge. This contribution focuses on analyzing and comparing the performance of a novel sleeve ferrite solution based on a nanocrystalline (NC) structure with several materials with different compositions. This component is able to provide a high initial permeability value at the same time that ma…

Benefits from energy policy synchronisation of Brazil’s North-Northeast interconnection

2020

Abstract During the last 10 years Brazil has accelerated the incorporation of new wind capacity into its power matrix. This situation has generated the need for increased transport capacity. However, there have been delays in the planning process for new transmission line construction, thus inducing trapped electricity in the system; in other words, electricity that cannot be dispatched to the interconnected system. Using system dynamics modelling, this paper assesses energy policy alternatives for improving the synchronisation between the construction of both power generation and transmission capacities. Simulation results show that policy synchronisation within the wind industry may provi…

Secondary users selection and sparse narrow-band interference mitigation in cognitive radio networks

2018

Spectrum scarcity is a critical problem that may reduce the effectiveness of wireless technologies and services. To address this problem, different spectrum management techniques have been proposed in the literature such as overlay cognitive radio (CR) where the unlicensed users can share the same spectrum with the licensed users. The main challenges in overlay CR networks are the identification and detection of the Primary User (PU) signals in a multi-source narrow-band interference (NBI) scenario. Therefore, in this paper, we investigate the performance of an orthogonal frequency division multiplexing (OFDM) overlay CR network with Secondary Users (SUs) and subcarriers selection schemes. …

Evaluation of Internet channels and their impacts on Irish mobile operators' business models

2013

Ademowo, Adewale Adebayo Evaluation of Internet Channels and their impacts on Irish Mobile Operators' Business Models Jyväskylä: University of Jyväskylä, 2013, 108 p. Mobile Technology and Business (Major in Information Systems Science), Master's Thesis Supervisor: Luoma, Eetu This study finds the impacts of the Internet channels on mobile operators’ business models with Ireland as a case. It reflects on the business model concepts, business models of mobile telecom industry and specifically Irish mobile operators; and evaluates and highlights the impacts of the internet channels used by the operators. This study uses exploratory case study as a methodology and qualitative method as an appr…

EECDC-MAC: An energy efficient cooperative duty cycle MAC protocol

2012

In this paper, we propose a novel energy efficient cooperative duty cycle MAC (EECDC-MAC) protocol in which sensor nodes use fixed wakeup rendezvous scheduling to exchange messages and a cooperative transmission mechanism to avoid overuse of nodes with lower residual energy. Numerical results demonstrate that the EECDC-MAC protocol can prolong the entire network longevity efficiently in comparison with an existing cooperative duty cycle MAC protocol, CDC-MAC, and another popular duty cycle MAC protocol, prediction wakeup MAC (PW-MAC) protocol.

Advanced Monitoring Systems Based on Battery-Less Asset Tracking Modules Energized through RF Wireless Power Transfer

2020

Asset tracking involving accurate location and transportation data is highly suited to wireless sensor networks (WSNs) featuring battery-less nodes that can be deployed in virtually any environment and require little or no maintenance. In response to the growing demand for advanced battery-less sensor tag solutions, this article presents a system for identifying and monitoring the speeds of assets in a WSN with battery-less tags that receive all their operating energy through radio frequency (RF) wireless power transfer (WPT) architecture, and a unique measurement approach to generate time-domain speed readouts. The assessment includes performance characteristics and key features of a syste…

Struggles for recognition: a content analysis of messages posted on the Internet

2012

Anders Johan W Andersen,1,2 Tommy Svensson31Department of Psychosocial Health, University of Agder, Norway; 2Nordic School of Public Health, Gothenburg, Sweden; 3Department of Behavioral Sciences and Learning, Linköping University, Linköping, SwedenBackground: The Internet has enlarged the possibilities of human communication and opened new ways of exploring perceptions of mental health. This study is part of a research project aiming to explore, describe, and analyze different discourses of mental health in Norway and Sweden, using material from Internet-based services.Aim: To examine messages posed by users of publicly available question-and-answer services and to descri…