In the most of DOA estimation methods, environmental noise model is considered to be uniform spatial white noise. However, in many applications this kind of modeling may not be appropriate and leads to considerable direction finding errors. Non-equal output noise power of array elements that causes nonuniform noise is one of these cases. The most important goal of this paper is the investigation and comparison of DOA estimation in presence of nonuniform noise using simulation as well as presenting a novel and effective method for DOA estimation in the mentioned situation. A novel low complexity algorithm for DOA estimation in presence of nonuniform spatial white noise is proposed. Additionally, the performance of the proposed method is simulated and compared with that of matrix completion based method and also iterative subspace estimation schemes for various parameters. The simulation results demonstrate that the proposed scheme achieves a considerable advantage over the existing schemes with remarkably lower complexity.

The objective of exploration seismology is to measure accurately reflected wavefields from subsurface interfaces in order to generate an image of the geological formations. More often the seismic data is non-uniformly sampled, i.e. the data is not acquired on an equidistantly spaced grid. This may result in artifacts during data processing that complicate interpretation. Sampling may be nonuniform because of human-related reasons such as: 1. Faulty equipment and positioning errors, 2. It may be due to environmental circumstances, such as cable feathering in marine acquisition induced by ocean currents or 3. Due to inaccessible areas in land acquisition (cities, rivers, and canyons).The generation of uniformly sampled data from nonuniformly sampled data is called reconstruction and many different methods to reconstruct seismic data have been published over the years. The method used in this paper is called reconstruction of nonuniformly sampled data with least squares Fourier transform. It is based on estimating the Fourier coefficients that describe the non-uniformly sampled data, and once these coefficients have been found the signal can be reconstructed on any suitable grid via an inverse Fourier transformation. The efficiency of the method is evaluated on both real and synthetic seismic. All necessary codes were written in MATLAB environment.

In this paper, a new method for extending and relaxing the noise-coupling (NC) technique is proposed to enhance the noise-shaping order without adding the number of integrators. The noise-shaping order of the introduced ∑∆ modulator whit applying a second-order noise-coupling technique is enhanced and its performance with optimizing the noise transfer function (NTF) zeros is improved. Also, by removing the analog adder at feedforward path and transferring it to a new feedback branch before the last integrator and adding second-order NC path can be decreased the input voltage swing to the quantizer. Thus, by improving the modulator resolution, power consumption can be reduced. Mathematical analyses and behavioural simulation results confirm the effectiveness of the new NC method. To examine its performance, a 2nd-order single loop ΣΔ modulator was designed. The new noise-coupling method is used to achieve the three-order noise shaping to increase the resolution with low complexity and low-power. The results show an outstanding improvement in signal-to-noise and distortion ratio (SNDR) compared to the conventional structure.

Introduction: Cochlear dead zones are defined as areas where the inner hair cells have been destroyed.Thresholds on the audiograms show the integrity of those parts of the ear that are tested. Care must be taken in interpretating audiograms. Thanks to the advances in understanding of cochlear functions, it is now possible to spot false responses that come from dead zones of the cochlea. Recently, cochlear dead regions have been detected via TEN (Threshold Equalizing Noise) test in which ipsilateral broadband noise and threshold shifting are used.Materials and Methods: A review of the literature on the subject of dead zones published from 1993 to 2003 was performed using Pubmed, Ebsco, Science Direct, Google Scholar Thieme ProQuest databases and library sources. key word: were "cochlear dead zone", "traveling wave", "ten (threshold equalizing noise) test", "ipsilateral noise" and "real-ear measurement for hearing aids prescription".Conclusion: Hearing aids fitting process for patients with severe and sloping sensory neural hearing loss must be noted specially by amplifying active zone and avoiding amplification for dead region i.e., offering amplification to the transition frequencies that have better hearing than others, those among the fine regions and the dead zones. Dead zone detection may help in hearing aids fitting and fine tuning.

In recent decades the effects of magnetic and electric fields on living cells and organisms have gained the increasedattention of researchers. In recent years, dielectrophoresis based microfluidics systems have been used to manipulatebiological micro particles, such as red blood cells, white blood cells, platelets, cancer cells, bacteria, yeast, microorganisms, proteins, DNA, etc. So most previous researchers have studied particle trajectory under theapplication of electric field in order to better design of such micro devices. In the current study the effect of nonuniformelectric field on a single cell is investigated. A neutral particle polarizes in the presence of electric field. It causes localchange in electrostatic potential distribution and local nonuniformity in electric field. These changes are ignored inprevious researches and effective dipole moment (EDM) approximation is applied to predict the DEP force exerted oncells. In the present research the effect of cell on electrostatic potential distribution and electric stresses acting on cellsurface is studied. To this end, the cell shape and internal boundary conditions on cell surface must be considered incomputational domain. To do this, Immersed Interface Method (IIM) which is a modified finite difference method isemployed. Some numerical results are presented to show the good accuracy of mentioned numerical method. Theelectric stresses on cell surface are calculated by Maxwell Stress Tensor (MST). Also some results are presented tovalidate the numerical solution and investigate the accuracy of EDM approximation. Other electrokinetic effects suchas electrophoresis and electro-osmosis are neglected in this study.

A new wideband Wilkinson Power Divider which use the nonuniform substrate integrated waveguide (NSIW) method is presented in this paper. This structure utilizes NSIWs instead of the uniform quarter wavelength SIWs in conventional Wilkinson power divider. The proposed structure is analyzed by odd and even mode analysis. The proper NSIW section widths can be extracted by using even mode while the divider resistances are achieved by odd mode analysis. Moreover using of half mode structure in the NSIW and two output ports reduces the overall size of the proposed divider. Finally a wideband Wilkinson power divider is designed and simulated to verify the proposed design method. A good return loss (S11, S22) and insertion loss (S21) across a very wideband width from 10 GHz to 20 GHz is achieved. Also, the isolation (S23) is better than -10 dB from 9.5 GHz to 21.5 GHz for the designed NSIW divider.

In this work, the propagation of the electrostatic drift waves is studied in a non-uniform quantum plasma medium. The analytical expression for dispersion relation of the waves is derived by taking into account the resistivity and quantum aspects of the medium. It has been shown that the quantum effects, alter the dispersion relation of the drift modes. The result is the appearance of modified electron diamagnetic drift waves as well as ion acoustic waves. Furthermore, the velocities of these waves are greater than their classical case. The graphical analysis also revealed that the quantum corrections cause electron branch of the drift waves to become propagative. In the presence of resistivity, the electron drift wave is always unstable, whereas the ion branch of the drift wave becomes damped. On the other hand, in the absence of quantum aspects and given zero resistivity, the two generated ion acoustic and electron drift waves are completely stable.

Teleoperation systems have attracted more attention in processes that human operator’s availability is difficult. In this paper, using retarded functions, teleoperation systems have been modeled as a special case of Network Control Systems (NCS) with nonuniform sampling and network delays. It is assumed that slave and master robots are linear and continues-time systems and input-delay approach is used for the stability analysis. Using the proposed Lyapunov function, the sufficient conditions for the stability of discrete network-based teleoperation system is proposed. It will be represented that the proposed conditions are less conservative than previous recent researches. Also an upper bound of sampling time for discrete control signals is computed in a manner that does not disturb the stability conditions. To meet this condition the problem is defined as the convex optimization program and is represented by the LMI terms. In the simulation part, the behavior of the teleoperation system under the nonuniform sampling is represented and the effect of sampling time on the trade-off between the stability and transparency has been studied.

In this paper, we introduce the notion of nonuniform semiorthogonal wavelet frame associated with nonuniform frame multiresolution analysis on non-Archimedean fields and provide their characterization by means of some basic equations in the frequency domain