In the present paper, the aeroelastic stability of helicopter rotor blade is determined using Aeroelastic Frequency Response Function. The conventional methods of aeroelastic stability usually use an iterative procedure while the present method does not require such approach. Aeroelastic Frequency Response Functions are obtained by inverting dynamic stiffness matrix of the aeroelastic system. S...

according to high costs of phase shifters in antenna arrays, new methods for beam steering without phase shifter were introduced. frequency diverse array (fda) concept is another approach to beam steering problem. in this structure, the subsequent antenna elements are fed with stepped discrete frequencies causing continuous scanning of space in time. so a range-angle dependent scanning is made ...

Event picking is used in many steps of seismic processing. We present an automatic event picking method that is based on a new attribute of seismic signals, the instantaneous traveltime. The calculation of the instantaneous traveltime consists of two separate but interrelated stages. First, a trace is mapped onto the time-frequency domain. Then the time-frequency representation is mapped back o...

Moderation policies of “free speech” and “safe space” have often been equated to lowand highcensorship levels. However, this paper proposes that moderation policies of “safe space” and “free speech” can also be thought of as a design choice that establishes norms of how individuals should treat each other in that discussion space. Analysis of word usage in matched Reddit communities provides ev...

This paper addresses robust estimation for the frequency offset of orthogonal frequency division multiplexing in non-Gaussian noise channels. We first propose a maximum-likelihood (ML) estimator in non-Gaussian noise modeled as a complex isotropic Cauchy process, and then present a simpler, yet still robust, estimator based on the ML estimator. From numerical results, it is confirmed that the p...

the economic growth and development programs in iran call for particular attention for environmental quality control and protection through designing proper sewage treatment and disposal. to design such system, 'the frequency analysis of rainfall is required for the estimation of quantities of flows. there are few places in iran, with adequate rainfall data to permit frequency analysis, an...

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