Basic properties of Davis-Wielandt shells are presented. Conditions on two operators A and B with the same Davis-Wielandt shells are analyzed. Special attention is given to the case when B is a compression of A, and when B = A∗, A, or (A∗)t, where A is the transpose of A with respect to an orthonormal basis. The results are used to study the point spectrum, approximate spectrum, and residual sp...

A method to detect and characterize a frequency hopping (FH) signal is proposed. The context is Spectrum Surveillance. Hence, no a priori information is available: the parameters of the modulation must be automatically determined. Spread spectrum (SS) modulations are well-known for their low probability of interception (LPI). Nevertheless the aim of this paper is to show that, using a time–freq...

Future lithography systems must produce more dense chips with smaller feature sizes, while maintaining the throughput of one wafer per sixty seconds per layer achieved by today’s optical lithography systems. To achieve this throughput with a direct-write maskless lithography system, using 25 nm pixels for 50 nm feature sizes, requires data rates of about 10 Tb/s. In a previous paper, we present...

Perceptual harmonic cepstral coefficients (PHCC) are proposed as features to extract from speech for recognition in noisy environments. A weighting function, which depends on the prominence of the harmonic structure, is applied to the power spectrum to ensure accurate representation of the voiced speech spectral envelope. The harmonics weighted power spectrum undergoes mel-scaled band-pass filt...

background: in patients undergoing mechanical ventilation, mucus production and secretion is high as a result of the endotracheal tube. because endotracheal suction in these patients is essential, chest physiotherapy techniques such as expiratory rib cage compression before endotracheal suctioning can be used as a means to facilitate mobilizing and removing airway secretion and improving alveol...

brown tumors may occur secondary to hyperparathyroidism in patients with chronic renal failure (ckd). they are increasingly rare because hyperparathyroidism in now diagnosed and treated at an early stage. we report 67-year-old man who had been on hemodialysis for crf for over 3 years, who presented with back pain over the thoracolumbar junction from 2 years ago and because of pain he could not ...

this research was performed to determine the efficiency effect of sedimentary environment of kerman city area on soil structure bycomparing natural and reconstituted consolidation curves. in this regard, four different criteria such as sensitivity strength, stresssensitivity, schmertman criteria and the result of the uniaxial compression test were used. the base of these criteria is to compare ...

in the hot compression test friction has a detrimental influence on the flow stress through the process and therefore, correcting the deformation curve for real behavior is very important for both researchers and engineers. in this study, a series of compression tests were simulated using abaqus software. in this study, it has been employed the taguchi method to design experiments by the factor...

we define a new type of spectrum, called δ-approximate spectrum, of an element a in a complex unital banach algebra a and show that the δ-approximate spectrum σ_δ (a) of a is compact. the relation between the δ-approximate spectrum and the usual spectrum is investigated. also an analogue of the classical gleason-kahane-zelazko theorem is established: for each ε>0, there is δ>0 such that if ϕ is...