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MATRIX FORMULATION OF SUPERSPACE ON 1D LATTICE WITH TWO SUPERCHARGES
No full textFollowing the approach developed by some of the authors in recent papers and using a matrix representation for the superfields, we formulate an exact supersymmetric theory with two supercharges on a one dimensional lattice. In the superfield formalism supersymmetry transformations are uniquely defined and do not suffer of the ambiguities recently pointed out by some authors. The action can be written in a unique way and it is invariant under all supercharges. A modified Leibniz rule applies when supercharges act on a superfield product and the corresponding Ward identities take a modified form but hold exactly at least at the tree level, while their validity in presence of radiative corrections is still an open problem and is not considered here
Self-similarity of higher order moving averages
Full text linkIn this work, higher-order moving average polynomials are defined by straightforward generalization of the standard moving average. The self-similarity of the polynomials is analyzed for fractional Brownian series and quantified in terms of the Hurst exponent H by using the detrending moving average method. We prove that the exponentH of the fractional Brownian series and of the detrending moving average variance asymptotically agree for the first-order polynomial. Such asymptotic values are compared with the results obtained by the simulations. The higher-order polynomials correspond to trend estimates at shorter time scales as the degree of the polynomial increases. Importantly, the increase of polynomial degree does not require to change the moving average window. Thus trends at different time scales can be obtained on data sets with the same size. These polynomials could be interesting for those applications relying on trend estimates over different time horizons (financial markets) or on filtering at different frequencies (image analysis)
Design of multi-frequency compact antennas for automotive communications
No full textTwo designs of multi-band antennas for automotive
communications are presented. Both antennas are designed to operate in four frequency bands (GSM, E-GSM, DCS, PCS) and are
intended to be integrated in a PCB, placed inside a plastic box and
mounted under the dashboard of the vehicle. The first design is
a planar printed antenna fully integrated into the printed circuit
board (PCB), thus reducing the cost virtually to zero; the second
design is a three dimensional antenna, which does not require any
dedicated space on the PCB. Both antennas have been designed
taking into account the presence of the other electronic components
on the PCB. The simulated reflection coefficients and radiation patterns of both antennas are in good agreement with prototype measurements
Design of multi-band compact antennas for automotive communications
No full textThis paper presents the design of two different quad-band antennas for GSM/DCS/PCS communication equipment to be mounted inside vehicles (cars, trucks, ...). The first solution is an antenna printed on a printed circuit board (PCB), thus reducing the cost virtually to zero, while the second solution is a three-dimensional patch antenna. Both antennas have been designed to be integrated on the PCB, with many other electronic components. The simulated return loss and radiation patterns are reported and analyzed
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