Laughter in speech has been studied mostly relying upon the spectral representation like formants and harmonics derived from the short-time spectrum. Significant changes appear to take place in the characteristics of glottal source of excitation during the production of laughter, but these changes have not been explored much. In this study, we examine the changes in the glottal vibration charac...

In this paper we introduce the PCPH (Pseudo-Chaotic Phase Hopping) telecommunication scheme, which is obtained by combining pseudo-chaotic encoding with N -ary phase shift keying. For this system, we address the problem of finding the optimal constellation labeling in order to minimize the error probability.

Research in the design of ultra-wideband (UWB) radio systems suggests di erent kinds of signal design criteria. After an introduction to UWB radio, a variety of sequence design problems, motivated by UWB system constraints, will be presented. Design for time-hopping, for spectral atness, for rapid acquisition, and for multiple access will be discussed, and some sample designs will be presented.

AbsuactFrequency-Hopping (FH) techniques in conjunction with coding have been proposed for indoor radio systems based on the fact that FH behaves as an intrinsic frequency diversity technique. In this paper we assess the performance of a FH-BPSK for other situations not previously considered in the literature. In particular, the effects of having a non-null correlation coeffiiient in function o...

This paper presents a subspace method for bland channel est imation based on a special output correlation matrix. T h e approach relies on the i.i.d. assumption of the data sequence and uses the cyclic prefix redundancy present in OFDM systems or single-carrier systems with frequency domain equalization. This method has an important feature that allows channels to be longer than the cyclic pref...

Indoor localization of persons and objects poses a great engineering challenge. Previously developed localization systems demonstrate the use of wideband techniques in ultrasound ranging systems. Direct sequence and frequency hopping spread spectrum ultrasound signals have been proven to achieve a high level of accuracy. A novel ranging method using the frequency hopping spread spectrum with fi...

We investigate revenue maximization problems in auctions for dynamic spectrum access. We consider the frequency division and spread spectrum methods of dynamic spectrum sharing. In the frequency division method, a primary spectrum user allocates portions of spectrum to different secondary users. In the spread spectrum method, the primary user allocates transmission powers to each secondary user...

Steganography is the art and science of hiding that a communication is taken place. It embeds the secret file (text, audio or image) in other carrier file. Audio information hiding has attracted more attentions recently. Spread spectrum (SS) technique has developed rapidly in this area due to the advantages of good robustness and immunity to noise attack. Spread spectrum techniques really of di...

Different from one-dimensional systems, nesting in two-dimensional (2D) systems is not perfect but some 2D systems still have Peierls instability and hidden nesting. This paper shows that the nextnearest neighbor (NNN) hopping which controls the nesting deviation, heavily suppresses the Peierls instability. There is a critical value for the NNN hopping, beyond which the Peierls instability is d...