4,659 research outputs found
Review and Perspectives of Micro/Nano Technologies as Key-Enablers of 6G
No full textTo date, 5G (5th generation of mobile communications) roll out has been going on for more than two years, and the most of it has still to come. Meanwhile, Key Performance Indicators (KPIs) and Key Enabling Technologies (KETs) of Beyond-5G (B5G) and 6G (6th generation of mobile communications) are already at stake, looking at 2030. Future networks will leverage autonomous and evolutionary characteristics, triggered by the cornerstone of Artificial Intelligence (AI), falling well-beyond the scopes of 5G. Besides, seamless increase of KPIs, across the transition from 5G to 6G, with 100-1000 times higher data rate per user, latency reduction and reliability improvement, also stepping into the domain of (sub-)THz and optical communications, will set unparalleled demands for Hardware (HW) systems and components. This work focuses on the envisaged gap existing between currently in use strategies for design of Hardware-Software (HW-SW) systems and what the AI-driven 6G will demand, in terms of adaptivity, flexibility and evolution. An important part is forecasted for Micro/Nano technologies, devices and systems, in enabling 6G functionalities, especially at the network edge, stimulating partial reconceptualization of the classical idea of HW, in fact, rising its level of abstraction
Privacy-cost trade-offs in smart electricity metering systems
No full textTrade-offs between privacy and cost are studied for a smart grid consumer, whose electricity consumption is monitoredin almost real time by the utility provider (UP) through smart meter (SM) readings. It is assumed that an electrical battery isavailable to the consumer, which can be utilized both to achieve privacy and to reduce the energy cost by demand shaping.Privacy is measured via the mean squared distance between the SM readings and a target load profile, while time-of-use (ToU)pricing is considered to compute the cost incurred. The consumer can also sell electricity back to the UP to further improve theprivacy-cost trade-off. Two privacy-preserving energy management policies (EMPs) are proposed, which differ in the way the targetload profile is characterized. A more practical EMP, which optimizes the energy management less frequently, is also considered.Numerical results are presented to compare the privacy-cost trade-off of these EMPs, considering various privacy indicators
Physical-Layer Secrecy for OFDM Transmissions Over Fading Channels
No full textThis paper considers the information theoretic secrecy rates that are achievable by an orthogonal frequency-division multiplexing (OFDM) transmitter/receiver pair in the presence of an eavesdropper that might either use an OFDM structure or choose a more complex receiver architecture. The analysis is made possible by modeling the system as a particular instance of a high dimensional multiple-input multiple-output wiretap channel. The secrecy capacity is formulated as a maximization problem under a trace constraint, and simple expressions are given for its high signal-to-noise (SNR) limit. The low rate limit of the secrecy outage probability is also evaluated under a fading channel model. As for the finite SNR case, the secrecy rates that can be achieved with particular inputs are considered. Numerical results are provided under a Rayleigh fading channel model and under dependence of the main and eavesdropper channels. The secrecy loss due to the OFDM structure constraints, and the information gain for an eavesdropper that uses amore complex receiver, are also considered
Non-coherent successive relaying and cooperation: principles, designs, and applications
No full textCooperative communication is capable of forming a virtual antenna array for each node (user) in a network by allowing the nodes (users) to relay the messages of others to the destination. Such a relay aided network may be viewed as a distributed multiple-input multiple-output (MIMO) system relying on the spatially distributed single antennas of the cooperating mobiles, which avoids the correlation of the antenna elements routinely encountered in conventional MIMO systems and hence attains the maximum achievable diversity gain. Therefore, the family of cooperative communication techniques may be regarded as a potential solution for future wireless networks. However, constrained by the half-duplex transmit/receive mode of most practical transceivers, the cooperative networks may impose a severe 50% throughput loss. As a remedy, successive relaying can be employed, which is capable of mimicking a full-duplex relay and thereby recovering much of the 50% throughput loss. Furthermore, for the sake of bypassing power-hungry and potentially excessive-complexity channel estimation, noncoherent detection techniques may be employed for multiple-antenna aided systems, because estimating all the associated channels may become unrealistic. Explicitly, the mobile-stations acting as relays cannot be realistically expected to estimate the source-to-relay channels. In order to motivate further research on noncoherent successive relaying aided systems, a comprehensive review of its basic concepts, fundamental principles, practical transceiver designs and open challenges is provide
Optimal demand-side management for joint privacy-cost optimization with energy storage
No full textThe smart meter (SM) privacy problem is addressed together with the cost of energy for the user. It is assumed that a storage device, e.g., an electrical battery, is available to the user, which can be utilized both to achieve privacy and to reduce the energy cost by modifying the energy consumption profile. Privacy is measured via the mean squared-error between the SM readings, which are reported to the utility provider (UP), and a target load; while time-of-use pricing is considered for energy cost calculation. The optimal trade-off between the achievable privacy and the energy cost is characterized by taking into account the limited capacity of the battery as well as the capability to sell energy to the UP. Extensive numerical simulations are presented to evaluate the performance of the proposed strategy for different system settings
Education and Training in St. Vincent and the Grenadines: A Partially Annotated Bibliography
No full textThis bibliography on “Education and Training in St. Vincent and the Grenadines” has been specifically prepared for the UWI School of Continuing Studies’ St. Vincent and the Grenadines Conference. It covers all aspects of education and training in St. Vincent and the Grenadines including: Academic achievement,economics of education, educational infrastructure, literacy and mathematics education
Colour, class and gender in post-emancipation St. Vincent, 1834-1884
No full textThis thesis examines the experiences of the inhabitants of
St. Vincent during the first fifty years of freedom. It
examines social changes, work opportunities and areas of
conflicts that developed during the period. It also details
the effects of the declining economy on the islanders. The
main subjects of the thesis are the agricultural labourers
who were freed from slavery. It investigates their working
lives, their attempts to achieve independent status as
freeholders and their family and religious experiences. It
also examines the changing attitudes towards them that were
held by the planter class, the clergy and colonial
officials, and how these views influenced the formation of a
free society. In particular, the thesis investigates how
perspectives of race, class and gender differed within the
island, and how these divergencies created hostilities
between different social groups often leading to unrest.
While the main focus of the thesis is St. Vincent, it
also compares conditions in St. Vincent with other Caribbean
islands and Britain. This has helped illustrate how some
local conditions, such as the lack of available land,
ineffective plantation management and economic factors,
reduced the opportunities for the freed people of St.
Vincent. However, it also illustrates a commonality of
experiences among the poor in both the Caribbean and
Britain. It illustrates how the lives of the poor in the
Caribbean were often restricted by the same class and gender
biases experienced in Britain, as well as by racial
prejudices held by the ruling authorities.
The thesis relies on a variety of source material.
Most of the primary sources were official Colonial Office
dispatches, newspapers and Wesleyan missionary letters and
reports. Throughout the thesis, I have questioned the
motivations of the writers of these documents and
interpreted the discourses they employed. I have also
attempted to place the findings of my research within
current debates among Caribbean historians of the postemancipation
period to illustrate the importance of further
gender analysis and research
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