Establishing measures for local stationarity is an open problem in the field of time-frequency analysis. One promising theoretical measure, known as the spread, provides a means for quantizing potential correlation between signal elements. In this paper we undertake the issue of generalizing techniques developed by the Authors to better estimate the spread of a signal. Existing techniques estim...

Properties of chirped-train waveforms such as their multi-band power spectra and the resulting point spread and ambiguity functions are described. Possible advantages in the utilization of chirped trains in “multi-spectral” imaging (i.e., imaging based on frequency sub-bands of the chirped train signal) allowing extraction of frequency dependent information with improved signal-to-noise ratio a...

A crucial assumption in the optimal auction literature is that each bidder’s valuation is known to be drawn from a unique distribution. In this paper, we study the optimal auction problem allowing for ambiguity about the distribution of valuations. Agents may be ambiguity averse (modeled using the maxmin expected utility model of Gilboa and Schmeidler 1989). When the bidders face more ambiguity...

In the paper we address the problem of constructing frequency hop codes for use in multiuser communication systems such as multiple-access spread-spectrum communications and multiuser radar and sonar systems. Previous frequency hopping techniques are reviewed. The construction of a new family of frequency hop codes called hyperbolic frequency hop codes is given. Exactly p-1 codes of length p-1 ...

We present a survey on the current status of the constructions of polyphase sequences with low correlation, discrete Fourier transform (DFT), and ambiguity in both time and phase domain, including some new insights and results. Firstly, we systematically introduce the concepts of phase-shift operators and ambiguity functions of sequences, and give a new construction of polyphase sequences from ...

In this paper the application of chaotic signals in continuous wave (CW) ranging systems is addressed. Diierent chaos generators that can be applied in this application are presented and analysed with respect to their signal properties. In the case of a CW ranging system the important requirement is an unambigu-ous range estimation. If classical correlation processing is applied in the CW rangi...

Economic evaluation of climate policy traditionally treats uncertainty by appealing to expected utility theory. Yet our knowledge of the impacts of climate policy may not be of sufficient quality to justify probabilistic beliefs. In such circumstances, it has been argued that the axioms of expected utility theory may not be the correct standard of rationality. By contrast, several axiomatic fra...

It has been shown that the fractional Fourier transform, recently very intensively investigated in mathematics, quantum mechanics, optics and signal processing, can be obtained as a special case of the earlier introduced linear coordinate transformations of the ambiguity function or Wigner distribution. Some applications of the generalized fractional transform on the time-frequency analysis are...

Advances in information technologies are narrowing the gap that traditionally existed between computing methods for radar signal processing, digital communications, and digital signal processing in general. A new field is becoming more stable as new applications and challenges are met for on board, real time operations. This field is termed computing methods for radar communications signal proc...

The problem of ground target detection with passive radars is considered. The design of an antenna array based on commercial elements is presented, based on a non-uniform linear array optimized according to sidelobe level requirements. Array processing techniques are applied in the cross-ambiguity function domain to exploit integration gain, system resolution and the sparsity of targets in this...