250 research outputs found
Fractal-fractional advection–diffusion–reaction equations by Ritz approximation approach
In this work, we propose the Ritz approximation approach with a satisfier function to solve fractalfractional advection–diffusion–reaction equations. The approach reduces fractal-fractional advection–diffusion– reaction equations to a system of algebraic equations; hence, the system can be solved easily to obtain the numerical solution for fractal-fractional advection–diffusion–reaction equations. With only a few terms of two variables-shifted
Legendre polynomials, this method is capable of providing
high-accuracy solution for fractal-fractional advection–diffusion–reaction equations. Numerical examples show that this
approach is comparable with the existing numerical method.
The proposed approach can reduce the number of terms of
polynomials needed for numerical simulation to obtain the
solution for fractal-fractional advection–diffusion–reaction
equations
China-Europe cooperation in the telecommunications: the case of China Unicom/Telefónica, 2002-2016
This research seeks to explore the driving forces behind the diverse pathways of telecommunications and, in particular, the rationale for international alliances in the context of globalisation and the extension of the value chain induced by technological change. It attempts to answer two interrelated questions: from China's side, why Telefónica and from this operator's side, why China? China was looking for a reliable technology partner for its weak market segments and a bridge to Latin America. Telefónica ambitioned to expand its mobile customer base in a country with high growth potential (NYT) while reducing through economies of scale equipment supply costs in an oligopolistic market. The research adopts a case study methodology and focuses on the service operators China Unicom and Telefónica de España in the years after the dotcom crash and before the arrival of the Covid-19 pandemic. The investigation is based on sources from the companies involved and relevant documents from specialised institutions. The study finds that the need for cooperation in the knowledge and capital-intensive services and the coincidence in strategies led to the frame of international alliances of companies
Теорія систем мобільних інфокомунікацій. Системна архітектура
Навчальний посібник містить опис логічних та фізичних структур, процедур,
алгоритмів, протоколів, принципів побудови і функціонування мереж
стільникового мобільного зв’язку (до 3G) і мобільних інфокомунікацій (4G і вище),
приділяючи увагу розгляду загальних архітектур мереж операторів мобільного
зв’язку, їх управління і координування, неперервності еволюції розвитку засобів
функціонування і способів надання послуг таких мереж. Посібник структурно має
сім розділів і побудований так, що складність матеріалу зростає з кожним
наступним розділом. Навчальний посібник призначено для здобувачів ступеня
бакалавра за спеціальністю 172 «Телекомунікації та радіотехніка», буде також
корисним для аспірантів, наукових та інженерно-технічних працівників за
напрямом інформаційно-телекомунікаційних систем та технологій.The manual contains a description of the logical and physical structures, procedures, algorithms, protocols, principles of construction and operation of cellular networks for mobile communications (up to 3G) and mobile infocommunications (4G and higher), paying attention to the consideration of general architectures of mobile operators' networks, their management, and coordination, the continuous evolution of the development of the means of operation and methods of providing services of such networks. The manual has seven structural sections and is structured in such a way that the complexity of the material increases with each subsequent chapter. The textbook is intended for applicants for a bachelor's degree in specialty 172 "Telecommunications and Radio Engineering", and will also be useful to graduate students, and scientific and engineering workers in the direction of information and telecommunication systems and technologies
Optimización de una Estación Base con Tecnología LTE-TDD en la Ciudad de Jinotepe
El presente trabajo presenta el uso de la tecnología LTE (Long Term Evolution) usando uno de los tipos de duplexaciones permitidos dentro de la tecnología de comunicación celular, TDD (Time Divison Duplex) para bandas no emparejada
Análise da utilização do 5G em aplicações de redes elétricas inteligentes
The Brazilian electrical system has particular characteristics that demand very specific operational requirements and Smart Grids applications. One example is the fact
of the system is mostly interconnected, with a large territorial extension and with most
of the electric generation being of hydraulic origin, what is a situation that allows the
inclusion of water resource monitoring as an Smart Grids application. In addition,
other applications are present, such as remote metering, energy management, automation, demand response, vehicular electrification, distributed generation and control of protection systems. One factor that makes these applications viable is the use
of communication technologies, which must meet specific requirements for each kind
of application. Therefore, a wide range of technologies need to be analyzed carefully
and technically for each case, such as WiMAX, NB-IoT, LoRa, Sigfox, Bluetooth,
Zigbee, GOES, Wi-Fi, Ingenu, 6LoWPAN, DASH7 and cellular technologies. In this
scenario, the telecommunications system in Brazil is constantly being updated and
is being prepared to receive the 5G cellular network, which has been analyzed in all
the aforementioned applications and is shown to be viable in most of them. In addi tion, 5G has been widely studied, being one of the most cited wireless communication
technologies in scientific publications related to Smart Grids. This scenario shows a
great interest of the scientific community of 5G in Smart Grids context.O sistema elétrico brasileiro possui características particulares que demandam requisitos operacionais e aplicações de redes elétricas inteligentes bastante específicas. Pode-se citar, por exemplo, o fato de o sistema ser majoritariamente interligado,
com grande extensão territorial e com a maior parte da geração elétrica sendo de
origem hidráulica, situação que permite a inclusão de monitoramento de recurso hídrico como uma aplicação de redes elétricas inteligentes. Além disso, outras aplicações estão presentes, tais como medição remota, gerenciamento de energia, automação, resposta de demanda, eletrificação veicular, geração distribuída e controle
de sistemas de proteção. Um fator que viabiliza estas aplicações é o uso de tecnologias de comunicação, as quais devem atender requisitos específicos para cada
uma delas. Sendo assim, uma vasta gama de tecnologias precisam ser analisadas
criteriosamente e tecnicamente para cada caso, como por exemplo WiMAX, NB-IoT,
LoRa, Sigfox, Bluetooth, Zigbee, GOES, Wi-Fi, Ingenu, 6LoWPAN, DASH7 e as diversas tecnologias celulares. Neste cenário, o sistema de telecomunicações no Brasil está em constante atualização e se prepara para a chegada da rede móvel 5G, o
qual foi analisado em todas as aplicações citadas e se mostra viável na maioria delas. Além disso, o 5G vem sendo amplamente estudado, sendo uma das tecnologias
de comunicação sem fio mais citadas em publicações científicas relacionadas às
redes elétricas inteligentes
Enrutamiento y seguridad de señalización en el núcleo de las redes móviles 5G stand-alone
Este TFG ofrece el estudio y análisis de la gestión de la señalización en el núcleo de redes móviles 5G Stand-Alone. Está basado en el estado actual de su estandarización, así como en la implantación real
de esta tecnología en las redes móviles existentes a nivel mundial. Mostrando la evolución y los cambios
más relevantes con respecto a las tecnologías móviles precedentes, pone foco en las funciones de red
específicamente definidas para el manejo de la señalización en el núcleo de las redes móviles 5G Stand-Alone, tanto a nivel de enrutamiento como de seguridad. Ofrece también un análisis específico de los escenarios de roaming, explorando casos de uso reales de señalización extremo a extremo.This TFG provides the study and analysis of the architecture and topology required for Core Network
Signaling in 5G Stand-Alone mobile networks. It is based on its current standardization status, as well
as in the current real implementations of this technology in the existing mobile networks worldwide.
Showing the evolution and the most relevant changes compared to the preceding mobile technologies, it
focuses on the network functions specifically defined for managing signaling in the core networks of 5G
Stand-alone mobile networks, both at routing level and security level. It also offers specific analysis of
roaming scenarios, exploring real end to end signaling use cases.Grado en Ingeniería Telemátic
Enabling Technology in Optical Fiber Communications: From Device, System to Networking
This book explores the enabling technology in optical fiber communications. It focuses on the state-of-the-art advances from fundamental theories, devices, and subsystems to networking applications as well as future perspectives of optical fiber communications. The topics cover include integrated photonics, fiber optics, fiber and free-space optical communications, and optical networking
Recent Advances in Wireless Communications and Networks
This book focuses on the current hottest issues from the lowest layers to the upper layers of wireless communication networks and provides "real-time" research progress on these issues. The authors have made every effort to systematically organize the information on these topics to make it easily accessible to readers of any level. This book also maintains the balance between current research results and their theoretical support. In this book, a variety of novel techniques in wireless communications and networks are investigated. The authors attempt to present these topics in detail. Insightful and reader-friendly descriptions are presented to nourish readers of any level, from practicing and knowledgeable communication engineers to beginning or professional researchers. All interested readers can easily find noteworthy materials in much greater detail than in previous publications and in the references cited in these chapters
Discrete Wavelet Transforms
The discrete wavelet transform (DWT) algorithms have a firm position in processing of signals in several areas of research and industry. As DWT provides both octave-scale frequency and spatial timing of the analyzed signal, it is constantly used to solve and treat more and more advanced problems. The present book: Discrete Wavelet Transforms: Algorithms and Applications reviews the recent progress in discrete wavelet transform algorithms and applications. The book covers a wide range of methods (e.g. lifting, shift invariance, multi-scale analysis) for constructing DWTs. The book chapters are organized into four major parts. Part I describes the progress in hardware implementations of the DWT algorithms. Applications include multitone modulation for ADSL and equalization techniques, a scalable architecture for FPGA-implementation, lifting based algorithm for VLSI implementation, comparison between DWT and FFT based OFDM and modified SPIHT codec. Part II addresses image processing algorithms such as multiresolution approach for edge detection, low bit rate image compression, low complexity implementation of CQF wavelets and compression of multi-component images. Part III focuses watermaking DWT algorithms. Finally, Part IV describes shift invariant DWTs, DC lossless property, DWT based analysis and estimation of colored noise and an application of the wavelet Galerkin method. The chapters of the present book consist of both tutorial and highly advanced material. Therefore, the book is intended to be a reference text for graduate students and researchers to obtain state-of-the-art knowledge on specific applications
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