172,576 research outputs found
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A unified model of the electrical power network
Traditionally, the different infrastructure layers, technologies and management activities associated with the design, control and protection operation of the Electrical Power Systems have been supported by numerous independent models of the real world network. As a result of increasing competition in this sector, however, the integration of technologies in the network and the coordination of complex management processes have become of vital importance for all electrical power companies.
The aim of the research outlined in this paper is to develop a single network model which will unify the generation, transmission and distribution infrastructure layers and the various alternative implementation technologies. This 'unified model' approach can support ,for example, network fault, reliability and performance analysis. This paper introduces the basic network structures, describes an object-oriented modelling approach and outlines possible applications of the unified model
Unified Performance Analysis of Mixed Line of Sight RF-FSO Fixed Gain Dual-Hop Transmission Systems
In this work, we carry out a unified performance analysis of a dual-hop fixed
gain relay system over asymmetric links composed of both radio-frequency (RF)
and unified free-space optics (FSO) under the effect of pointing errors. The RF
link is modeled by the Nakagami- fading channel and the FSO link by the
Gamma-Gamma fading channel subject to both types of detection techniques (i.e.
heterodyne detection and intensity modulation with direct detection (IM/DD)).
In particular, we derive new unified closed-form expressions for the cumulative
distribution function, the probability density function, the moment generation
function, and the moments of the end-to-end signal-to-noise ratio of these
systems in terms of the Meijer's G function. Based on these formulas, we offer
exact closed-form expressions for the outage probability, the higher-order
amount of fading, and the average bit-error rate of a variety of binary
modulations in terms of the Meijer's G function. Further, an exact closed-form
expression for the end-to-end ergodic capacity for the Nakagami--unified FSO
relay links is derived in terms of the bivariate G function. All the given
results are verified via Computer-based Monte-Carlo simulations
On the Computation of the Higher Order Statistics of the Channel Capacity over Generalized Fading Channels
The higher-order statistics (HOS) of the channel capacity
, where denotes the
order of the statistics, has received relatively little attention in the
literature, due in part to the intractability of its analysis. In this letter,
we propose a novel and unified analysis, which is based on the moment
generating function (MGF) technique, to exactly compute the HOS of the channel
capacity. More precisely, our mathematical formalism can be readily applied to
maximal-ratio-combining (MRC) receivers operating in generalized fading
environments (i.e., the sum of the correlated noncentral chi-squared
distributions / the correlated generalized Rician distributions). The
mathematical formalism is illustrated by some numerical examples focussing on
the correlated generalized fading environments.Comment: Submitted to IEEE Wireless Communications Letter, February 18, 201
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Survey of unified approaches to integrated-service networks
The increasing demand for communication services, coupled with recent technological advances in communication media and switching techniques, has resulted in a proliferation of new and expanded services. Currently, networks are needed which can transmit voice, data, and video services in an application-independent fashion. Unified approaches employ a single switching technique across the entire network bandwidth, thus, allowing services to be switched in an application-independent manner. This paper presents a taxonomy of integrated-service networks including a look at N-ISDN, while focusing on unified approaches to integrated-service networks.The two most promising unified approaches are burst and fast packet switching. Burst switching is a circuit switching-based approach which allocates channel bandwidth to a connection only during the transmission of "bursts" of information. Fast packet switching is a packet switching-based approach which can be characterized by very high transmission rates on network links and simple, hardwired protocols which match the rapid channel speed of the network. Both approaches are being proposed as possible implementations for integrated-service networks. We survey these two approaches, and also examine the key performance issues found in fast packet switching. We then present the results of a simulation study of a fast packet switching network
Re-thinking technology and its growing role in enabling patient empowerment
© The Author(s) 2018. The presence and increase of challenges to eHealth in today’s society have begun to generate doubts about the capability of technology in patient empowerment, especially within the frameworks supporting empowerment. Through the review of existing frameworks and articulation of patient demands, weaknesses in the current application of technology to support empowerment are explored, and key constituents of a technology-driven framework for patient empowerment are determined. This article argues that existing usage of technology in the design, development and implementation of patient empowerment in the healthcare system, although well intentioned, is insufficiently constituted, primarily as a result of fragmentation. Systems theory concepts such as holism and iteration are considered vital in improving the role of technology in enabling patient empowerment
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