134,879 research outputs found
Nonlinear Switched-Capacitor Networks: Basic Principles and Piecewise-Linear Design
The applicability of switched-capacitor (SC) components to the design of nonlinear networks is extensively discussed in this paper. The main objective is to show that SC's can be efficiently used for designing nonlinear networks. Moreover, the design methods to be proposed here are fully compatible with general synthesis methods for nonlinear n -ports. Different circuit alternatives are given and their potentials are evaluated.Office of Naval Research (USA) N00014-76-C-0572Comisión Interministerial de Ciencia y Tecnología 0235/81Semiconductor Research Corporation (USA) 82-11-00
Achieving the Dispatchability of Distribution Feeders through Prosumers Data Driven Forecasting and Model Predictive Control of Electrochemical Storage
We propose and experimentally validate a control strategy to dispatch the
operation of a distribution feeder interfacing heterogeneous prosumers by using
a grid-connected battery energy storage system (BESS) as a controllable element
coupled with a minimally invasive monitoring infrastructure. It consists in a
two-stage procedure: day-ahead dispatch planning, where the feeder 5-minute
average power consumption trajectory for the next day of operation (called
\emph{dispatch plan}) is determined, and intra-day/real-time operation, where
the mismatch with respect to the \emph{dispatch plan} is corrected by applying
receding horizon model predictive control (MPC) to decide the BESS
charging/discharging profile while accounting for operational constraints. The
consumption forecast necessary to compute the \emph{dispatch plan} and the
battery model for the MPC algorithm are built by applying adaptive data driven
methodologies. The discussed control framework currently operates on a daily
basis to dispatch the operation of a 20~kV feeder of the EPFL university campus
using a 750~kW/500~kWh lithium titanate BESS.Comment: Submitted for publication, 201
Floquet theory of neutrino oscillations in the earth
We review the Floquet theory of linear differential equations with periodic
coefficients and discuss its applications to neutrino oscillations in matter of
periodically varying density. In particular, we consider parametric resonance
in neutrino oscillations which can occur in such media, and discuss
implications for oscillations of neutrinos traversing the earth and passing
through the earth's core.Comment: LaTeX, 28 pages, 8 eps figures. Contribution to the special issue of
Yad. Fiz. dedicated to the memory of A.B. Migda
Introduction to Random Signals and Noise
Random signals and noise are present in many engineering systems and networks. Signal processing techniques allow engineers to distinguish between useful signals in audio, video or communication equipment, and interference, which disturbs the desired signal. With a strong mathematical grounding, this text provides a clear introduction to the fundamentals of stochastic processes and their practical applications to random signals and noise. With worked examples, problems, and detailed appendices, Introduction to Random Signals and Noise gives the reader the knowledge to design optimum systems for effectively coping with unwanted signals.\ud
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Key features:\ud
• Considers a wide range of signals and noise, including analogue, discrete-time and bandpass signals in both time and frequency domains.\ud
• Analyses the basics of digital signal detection using matched filtering, signal space representation and correlation receiver.\ud
• Examines optimal filtering methods and their consequences.\ud
• Presents a detailed discussion of the topic of Poisson processed and shot noise.\u
Discrete scale invariance and complex dimensions
We discuss the concept of discrete scale invariance and how it leads to
complex critical exponents (or dimensions), i.e. to the log-periodic
corrections to scaling. After their initial suggestion as formal solutions of
renormalization group equations in the seventies, complex exponents have been
studied in the eighties in relation to various problems of physics embedded in
hierarchical systems. Only recently has it been realized that discrete scale
invariance and its associated complex exponents may appear ``spontaneously'' in
euclidean systems, i.e. without the need for a pre-existing hierarchy. Examples
are diffusion-limited-aggregation clusters, rupture in heterogeneous systems,
earthquakes, animals (a generalization of percolation) among many other
systems. We review the known mechanisms for the spontaneous generation of
discrete scale invariance and provide an extensive list of situations where
complex exponents have been found. This is done in order to provide a basis for
a better fundamental understanding of discrete scale invariance. The main
motivation to study discrete scale invariance and its signatures is that it
provides new insights in the underlying mechanisms of scale invariance. It may
also be very interesting for prediction purposes.Comment: significantly extended version (Oct. 27, 1998) with new examples in
several domains of the review paper with the same title published in Physics
Reports 297, 239-270 (1998
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