Consider s + 1 univariate normal populations with common variance σ2 and means μi, i = 0, 1, . . . , s, constrained by the tree-order restrictions μ0 ≤ μi, i = 1, 2, . . . , s. For certain sequences μ0, μ1, . . . the maximum likelihood-based estimator (MLBE) of μ0 diverges to −∞ as s → ∞ and its bias is unbounded. By contrast, the bias of an alternative estimator of μ0 proposed by Cohen and Sac...

This paper presents the extension of an audio watermarking approach to the blind detection of multiple watermarks. The underlying statistical watermarking method working in the fourier domain with different test functions is investigated. The extension of this semiprivate watermarking method to enable a blind detection is presented. To enable the embedding of multiple watermarks the algorithm d...

This paper deals with the question how various lInaturalll conditions posed on time-frequency distribution functions prevent them to be non-negative everywhere for all signals. The attention is mainly restricted to distribution functions that involve the signal bilinearly. This paper summarizes and extends results recently obtained; the emphasis is on a coherent presentation of these results, r...

in this research, the daily precipitation data of 1437 synoptic, climatic and rain gauging stations of iran in the time interval 1961- 2004 (equal to 15705 days) was utilized. using kriging geostatistics method, the data were interpolated on the pixels of 15 *15km2, so as an array to the dimension of 15705 * 7187 was formed. to identify the fittest distribution of the days with over 5.0mm preci...

abstract spi is based on fitting a gamma distribution to precipitation amounts in selected periods. based on current research, the gamma distribution may not be fitted to annual precipitation of some regions. in order to evaluate this subject, annual precipitation have been used during 1958- 2007 at 11 synoptic stations in iran. in first step, values of spi and frequency of different classes of...

The Wigner distribution (WD) possesses a number of desirable mathematical properties relevant time-frequency analysis. However, the presence of interference terms renders the WD of multicomponent signals extremely di cult to interpret. In this work, we propose an adaptivedecomposition of the WD using extended libraries of orthonormal bases. A prescribed signal is expanded on a basis of adapted ...

We investigate the time-frequency characteristics of high-order harmonics generated in atomic gases by intense femtosecond laser pulses, using the Wigner distribution function. The dynamically induced chirp of high harmonics is calculated both quantum mechanically and semiclassically, and a good agreement between them is reached as long as the tunneling effect is properly taken into account. Us...

Digital modulation signals such as FSK are time-varying signals that can he represented in the time-frequency representation. The smooth lag-windowed Wigner-Ville distribution (SLWWVD) is proposed as a method to obtain accurate time-frequency representation of FSK signals used in HF (High Frequency) radio communications. Unlike existing time-frequency distributions such as the windowed Wigner-V...