Signal to Noise Ratio

In Earth observation programs there is a need of passive low frequency (L-band) measurements to monitor soil moisture and ocean salinity with high spatial resolution 10-20 Km, a radiometric resolution of 1K and a revisit time of 1-3 days [1]. Compared to total power radiometers aperture synthesis interferometric radiometers are technologically attractive because of their reduced mass and hardware requirements. In this field it should be mentioned the one-dimensional (1-D) linear interferometer ESTAR developed by NASA [2] and MIRAS a two-dimensional (2-D) Y-shaped interferometer currently under study by European Space Agency (ESA) [3]. Interferometer radiometers measure the correlation between pairs of nondirective antennas. Each complex correlation is a sample of the "visibility" function which, in the ideal case, is the spatial Fourier transform of the brightness temperature distribution. Since most receiver phase and amplitude errors can be hardware calibrated, Fourier based iterative inversion methods will be useful when antenna errors are small, their radiation voltage patterns are not too different, and mutual coupling is small. In order to minimize on-board hardware requirements-antennas, receivers and correlators-the choice of the interferometer array shape is of great importance since it determines the (u; v) sampling strategy and the minimum number of visibility samples required for a determined aliasing level. In this sense, Y-shaped and triangularshaped arrays with equally spaced antennas are optimal. The main contribution of this paper is a technique that allows us to process the visibility samples over the hexagonal sampling grids given by Y-shaped and triangular-shaped arrays with standard rectangular FFT routines. Since no interpolation processes are involved, the risk of induced artifacts in the recovered brightness temperature over the wide field of view required in Earth observation missions is minimized and signal to noise ratio (SNR) is preserved.

Abstract—In Earth observation programs there is a need of passive low frequency (L-band) measurements to monitor soil moisture and ocean salinity with high spatial resolution 10–20 Km, a radiometric resolution of 1K and a revisit time of 1–3 days [1]. Compared to total power radiometers ...

Under the two initial 1-D one parameter velocity distribution forms (one is normal, the other is exponential), the z direction scale height evolution of normal neutron stars in the Galaxy is studied by numerical simulation. We do statistics for the cases at different time segments, also do statistics for the cumulative cases made of each time segment. The results show in the cumulative cases the evolution curves of the scale heights are smoother than in the each time segment, i.e., the cumulation improve the signal-to-noise ratio. Certainly the evolution cases are different at different Galactic disk locations, which also have very large difference from the average cases in the whole disk. In the initial stages of z evolution of normal neutron stars, after the beginning transient states, the cumulative scale heights increase linearly with time, and the cumulative scale height increasing rates have linear relationship with the initial velocity distribution parameters, which have larg...

In our previous study we have shown that identification of bacteria species with the use of Fresnel diffraction patterns is possible with high accuracy and at low cost. Fresnel diffraction patterns were recorded with the optical system with converging spherical wave illumination. Obtained experimental results have shown that colonies of specific bacteria species generate unique diffraction signatures. Features used for building classification models and thus for identification were simply mean value and standard deviation calculated of pixel intensities within regions of interest called rings. This work presents new, interpretable features denoting morphological and textural properties of the Fresnel diffraction patterns and their verification with the use of the statistical analysis workflow specially developed for bacteria species identification. As data set of bacteria species diffraction patterns it is very important to find features that differentiate species in the best manner. This task includes two steps. The first is finding and extracting new, interpretable features that can potentially be better for bacteria species differentiation than the ones used before. While the second one is deciding which of them are the best for identification purposes. The new features are calculated basing on normalized diffraction patterns and central statistical moments. For the verification the analysis workflow based on ANOVA for feature selection, LDA, QDA and SVM models for classification and identification and CV, sensitivity and specificity for performance assessment of the identification process, are applied. Additionally, the Fisher divergence method also known as signal to noise ratio (SNR) for feature selection was exploited.

Towards establishing electrical interfaces with patterned in vitro neurons, we have previously described the fabrication of hybrid elastomer-glass devices polymer-on-multielectrode array technology and obtained single-electrode recordings of extracellular potentials from confined neurons . Here, we demonstrate the feasibility of spatially localized multisite recordings from individual microchannel-guided neurites extending from microwell-confined somas with good signal-to-noise ratios (20 dB) and spike magnitudes of up to 300 V.

Due to influence of compressibility, shock wave, instabilities, and turbulence on supersonic flows, current flow visualization and imaging techniques encounter some problems in high spatiotemporal resolution and high signal-to-noise ratio (SNR) measurements. Therefore, nanoparticle based planar laser scattering method (NPLS) is developed here. The nanoparticles are used as tracer, and pulse planar laser is used as light source in NPLS; by recording images of particles in flow field with CCD, high spatiotemporal resolution supersonic flow imaging is realized. The flow-following ability of nanoparticles in supersonic flows is studied according to multiphase flow theory and calibrating experiment of oblique shock wave. The laser scattering characteristics of nanoparticles are analyzed with light scattering theory. The results of theoretical and experimental studies show that the dynamic behavior and light scattering characteristics of nanoparticles highly enhance the spatiotemporal resolution and SNR of NPLS, with which the flow field involving shock wave, expansion, Mach disk, boundary layer, sliding-line, and mixing layer can be imaged clearly at high spatiotemporal resolution.

A globally convergent adaptive control scheme for robot motion control with the following features is proposed. First, the adaptation law possesses enhanced robustness with respect to noisy velocity measurements. Second, the controller does not require the inclusion of high gain loops that may excite the unmodeled dynamics and amplify the noise level. Third, we derive for the unknown parameter design a relationship between compensator gains and closed-loop convergence rates that is independent of the robot task. A simulation example of a two-DOF manipulator features some aspects of the control scheme.

Topic detection with large and noisy data collections such as social media must address both scalability and accuracy challenges. KeyGraph is an efficient method that improves on current solutions by considering keyword cooccurrence. We show that KeyGraph has similar accuracy when compared to state-of-the-art approaches on small, well-annotated collections, and it can successfully filter irrelevant documents and identify events in large and noisy social media collections. An extensive evaluation using Amazon’s Mechanical Turk demonstrated the increased accuracy and high precision of KeyGraph, as well as superior runtime performance compared to other solutions.

This paper presents an application, "LentInfo", which is a system used to provide information about programmes for the Festival Lent in Slovenia. The Festival Lent consists of different open-air theatre and music performances and raws more than 400,000 visitors per year. This application is based on a Hidden Markov Model (HMM) speech recogniser, and the dialogue construction and management is done using the CSDP (Common Spoken Dialogue Platform) dialogue management system. It is represented as a finite-state structure. The dialogue can be specified in a script using simple syntax description. The dialogue manager is multi-application oriented, so it can easily be upgraded for new applications. If some new concepts are needed, only new actions need be added to the existing ones. Currently, prompt messages are prerecorded, but it is also possible to include a speech synthesis system depending on the needs of the application. Error recovery during the dialogue is done with user confirmation of the recognised input speech. The results are presented for tests performed in the year 2001. The results are analyzed according to the phone type (fixed/mobile), signal to noise ratio, dialogue path, etc. Although some calls where carried out using mobile phones from noisy festival places, the performance of the system decreased only slightly under these conditions.

This paper presents a novel structure of wideswing CMOS voltage buffer, which is based on the flipped voltage follower. When compared with the previously established buffer based on the same principle, the proposed circuit is less complex and consumes less power while attaining wide bandwidth and high slew-rate. Simulated results of the proposed buffer using a 0.35µm CMOS process are provided. I.

We propose the audio inpainting framework that recovers portions of audio data distorted due to impairments such as impulsive noise, clipping, and packet loss. In this framework, the distorted data are treated as missing and their location is assumed to be known. The signal is decomposed into overlapping time-domain frames and the restoration problem is then formulated as an inverse problem per audio frame. Sparse representation modeling is employed per frame, and each inverse problem is solved using the Orthogonal Matching Pursuit algorithm together with a discrete cosine or a Gabor dictionary. The Signal-to-Noise Ratio performance of this algorithm is shown to be comparable or better than state-of-the-art methods when blocks of samples of variable durations are missing. We also demonstrate that the size of the block of missing samples, rather than the overall number of missing samples, is a crucial parameter for high quality signal restoration. We further introduce a constrained Matching Pursuit approach for the special case of audio declipping that exploits the sign pattern of clipped audio samples and their maximal absolute value, as well as allowing the user to specify the maximum amplitude of the signal. This approach is shown to outperform state-of-the-art and commercially available methods for audio declipping in terms of Signal-to-Noise Ratio.

This report describes separation and detection of chlorophenoxy acid herbicides spiked in drinking water by the technique combining solid-phase extraction, fieldamplified sample stacking, capillary electrophoresis, and potential gradient detection. The herbicide solution (400 mL) was concentrated to 0.1 mL by the solid-phase extraction procedure. The buffer containing 3 mM ammonia and 0.3 mM hydroxypropyl-bcyclodextrin was adjusted to pH 9.0 with ammonia. The sample solution was injected into the capillary to 30% of the whole length, and 29 kV and 9 kV were employed for field-amplified sample stacking and separation, respectively. The herbicides were baseline separated and the detection limits with the above combined techniques were in the range of 1-4610 22 ng/mL.

There is a vast demand for in vivo methods for the detection of skin cancer, one of the most dangerous skin lesions. Use of near infrared Fourier transform (NIR-FT)-Raman spectroscopy virtually eliminates the fluorescence of the normal cell constituents and provides a signal to noise ratio, r SN , large enough to successfully evaluate the spectra using chemometric methods. A novel fiber optic probe for NIR-FT-Raman spectroscopy was used, which allows sterilization and the prevention of hazards due to laser radiation and makes in vivo measurements possible. The Raman spectra of normal skin are dominated by the connective tissue, mainly collagen type I. The Raman spectra of skin with inflammatory diseases show an increased lipid and water content. Kaposi sarcomas show typical features of tumors mainly in the amide III and the protein backbone range. A clear separation of Raman spectra of normal skin from those of benign and malignant neoplasms can be achieved by cluster analysis. However, the unequivocal diagnosis of skin cancer needs investigation of a larger number of more defined skin samples, taking into consideration the concurrent appearance of different skin symptoms like coloring and inflammation. cal fibers are used in Raman endoscopes [14] for measurement.

Acetohydroxy acid synthase (AHAS) and related enzymes catalyze the production of chiral compounds [(S)-acetolactate, (S)-acetohydroxybutyrate, or (R)-phenylacetylcarbinol] from achiral substrates (pyruvate, 2-ketobutyrate, or benzaldehyde). The common methods for the determination of AHAS activity have shortcomings. The colorimetric method for detection of acyloins formed from the products is tedious and does not allow time-resolved measurements. The continuous assay for consumption of pyruvate based on its absorbance at 333 nm, though convenient, is limited by the extremely small extinction coefficient of pyruvate, which results in a low signal-to-noise ratio and sensitivity to interfering absorbing compounds. Here, we report the use of circular dichroism spectroscopy for monitoring AHAS activity. This method, which exploits the optical activity of reaction products, displays a high signal-to-noise ratio and is easy to perform both in time-resolved and in commercial modes. In addition to AHAS, we examined the determination of activity of glyoxylate carboligase. This enzyme catalyzes the condensation of two molecules of glyoxylate to chiral tartronic acid semialdehyde. The use of circular dichroism also identifies the product of glyoxylate carboligase as being in the (R) configuration.

This paper deals with iterative maximum-likelihood synchronization of a scalar parameter. An efficient implementation of the Newton-Raphson (NR) maximum-search method is proposed. Considering the latter implementation, the NR approach is shown to be an attractive alternative to synchronization methods based on the expectation-maximization (EM) algorithm. Simulation results for the case of phase-offset synchronization show that NR method usually increases the speed of convergence of the synchronization algorithm.

Falls have become a common health problem among older adults. In previous study, we proposed an acoustic fall detection system (acoustic FADE) that employed a microphone array and beamforming to provide automatic fall detection. However, the previous acoustic FADE had difficulties in detecting the fall signal in environments where interference comes from the fall direction, the number of interferences exceeds FADE's ability to handle or a fall is occluded. To address these issues, in this paper, we propose two blind source separation (BSS) methods for extracting the fall signal out of the interferences to improve the fall classification task. We first propose the single-channel BSS by using nonnegative matrix factorization (NMF) to automatically decompose the mixture into a linear combination of several basis components. Based on the distinct patterns of the bases of falls, we identify them efficiently and then construct the interference free fall signal. Next, we extend the single-channel BSS to the multichannel case through a joint NMF over all channels followed by a delay-and-sum beamformer for additional ambient noise reduction. In our experiments, we used the Microsoft Kinect to collect the acoustic data in realhome environments. The results show that in environments with high interference and background noise levels, the fall detection performance is significantly improved using the proposed BSS approaches.

Lithium salts have been widely used in the treatment of mood disorders, but the mechanism of action is still not clear. In this work, a methodology for two-dimensional Lithium-7 imaging on clinical systems is presented. The data were acquired using a phosphorus volume head coil that was re-tuned for the Lithium-7 frequency. A spectroscopic sequence was used to acquire the fi-ee induction decay (FID) alter volume excitation using a hard pulse. The results obtained on the head of patients undergoing lithium treatment (n = 7, 0.6 mEq/l average serum level) demonstrate that images of adequate signal to noise ratio (100:1) can be obtained in acceptable imaging times (55 min)using the proposed methodology. The distribution of 7Li appears uniform in the brains of the patients studied. ~-~

A new and powerful method of spectral analysis, which is named the "Sompi" method after a Japanese word, is introduced and applied to low-frequency seismograms. The Sompi method is based on an autoregressive (AR) process model, which is different from an ordinary prediction type AR model. In the ordinary AR model the AR coefficients predict the present observation from the past observations so that they are determined by minimizing the prediction error. The model implicitly assumes that the past observations are noise-free and that only the present observation consists of signal and noise. The method thus gives an unbiased estimate of the linear relationship among the past data and the present signal. In our AR model the AR coefficients extract signals from the time series so that they are determined by minimizing the extraction residual. The model assumes that each observation, either past or present, consists of signal and noise. The method thus gives an unbiased estimate of the linear relationship among the successive signals. Those who wish to make an unbiased spectral estimation for the signal must therefore minimize the extraction residual, rather than the prediction error. Minimization of the extraction residual leads to an eigenvalue problem of a non-Toeplitz matrix of autocovariance. The minimum eigenvalue yields the extraction residual which is an estimate of the noise power. The corresponding eigenvector constitutes the AR coefficients whose characteristic equation gives the complex frequencies (frequencies and decay or growth rates) of the signals extracted. The complex amplitudes (amplitudes and phases) are then determined through a least squares procedure. The Sompi method thus first retrieves medium-sensitive parameters, frequencies, and Q and then excitation-sensitive parameters, amplitudes, and phases. From the practical point of view it is not feasible to apply the Sompi method directly to such data as the Earth's free oscillations in which spectral peaks are densely and nonuniformly distributed over the entire frequency domain. We propose an algorithm of aliased sampling which enables us to apply the Sompi method to such data. In this algorithm the time series is first narrowly and sharply band-pass filtered. The resultant time series is then decimated at a rate corresponding to the bandwidth of the filter. The contributions of all the decimated time series, which may mutually lag in time, are stacked into the matrix elements of autocovariance for the eigenvalue problem. The Sompi method with this algorithm is tested against a synthetic seismogram to see the resolvability of the two modes closely spaced in frequency. The Sompi method is next applied to the seismograms of the 1977 Sumbawa Island earthquake recorded in the International Deployment of Accelerometers network. First, the two radial modes oSo and 1So are analyzed to examine the uniformity of their spectral parameters among different stations. Second, the fundamental multipiers o& (1 = 5-43) are analyzed to see how their initial amplitudes and phases oscillate with respect to I at one station. Third, the gravest mode oS2 is analyzed in an attempt to resolve the five singlets with their Q values. Fourth, the analysis is made for the coupled multiplets oSt-oTt+• (1 = 10-12) to observe their mutual repulsion in frequency and their mutual attraction in decay rate. Fifth, the core mode 7S3, a mode with most of its energy confined to the inner core, is detected. All five experiments demonstrate remarkable accuracy and resolvability of the Sompi method. ]. Most of these studies owe a debt to the improvement of the quality of data and progress in computer technology. The former has been guaranteed by the installation of the worldwide digital seismic observation network (for example, International Deployment of Accelerometers (IDA), Seismic Research Observatory (SRO), and GEO-SCOPE). The latter has enabled us not only to utilize a huge quantity of data but also to apply a computationally involved algorithm for analysis.

A general methodology for rating both performance and potential of lidar systems used for detection of atmospheric trace constituents including pollutants and gas leaks is developed. By individually examining and decomposing the contribution of both lidar system parameters and atmospheric operating conditions on signal-to-noise-ratio, a generalized figure of merit, V , for lidar quality is introduced and evolved. Computer simulations based on V and atmospheric parameters are carried out to determine achievable lidar performance. A simple design procedure is outlined for determination of lidar instrumentation parameters to ensure the best monitoring efficiency for a given set of initial parameters/requirements, including operation range, minimum detectable gas concentration, and so on.

This work considers PSK with noncoherent demodulation. It is shown that by performing noncoherent demodulation over an increased observation interval, the performance approaches that of coherent PSK. This block demodulation technique of PSK is a natural generalization of differentially coherent detection and yields improved SNR performance. PSK with noncoherent block demodulation could be very attractive for harsh channels wich are power and bandwidth limitted, such as in Mobile Digital Cellular systems. reference used in demodulation is simply the previous received symbol.

This paper considers the K-user cognitive interference channel with one primary and K − 1 secondary/cognitive transmitters with a cumulative message sharing structure, i.e., cognitive transmitter i ∈ [2 : K] knows non-causally all messages of the users with index less than i. We propose a computable outer bound valid for any memoryless channel. We first evaluate the sum-rate outer bound for the high-SNR linear deterministic approximation of the Gaussian noise channel. This is shown to be capacity for the 3-user channel with arbitrary channel gains and the sum-capacity for the symmetric K-user channel.

The a priori signal-to-noise ratio (SNR) plays an important role in many speech enhancement algorithms. In this paper we present a data-driven approach to a priori SNR estimation. It may be used with a wide range of speech enhancement techniques, such as, e.g., the minimum mean square error (MMSE) (log) spectral amplitude estimator, the super Gaussian joint maximum a posteriori (JMAP) estimator, or the Wiener filter. The proposed SNR estimator employs two trained artificial neural networks, one for speech presence, one for speech absence. The classical decision-directed a priori SNR estimator by Ephraim and Malah is broken down into its two additive components, which now represent the two input signals to the neural networks. Both output nodes are combined to represent the new a priori SNR estimate. As an alternative to the neural networks, also simple lookup tables are investigated. Employment of these data-driven nonlinear a priori SNR estimators reduces speech distortion, particularly in speech onset, while retaining a high level of noise attenuation in speech absence.

In wireless environment, the channels are really affected by a number of factors such as: fading, interference, noise. In most of wireless communications, we have applied the training sequences as known signal at the receiver for estimating the channel as well as the transmitted signal. Nowadays, many paid services in the entertainment industry have required the high security for their data and this issue is challenge which needs to be solved. Recently, the semi-blind channel estimations have contributed in term of remarkable enhancement in the total bandwidth efficiency of multipleinput multiple-output (MIMO) systems. To obtain the high data rate demands, there is a fewer training symbols using in these semi-blind algorithms. However, each system model must be satisfied the safe data for both the suppliers and the customers. Based on the information theory, we propose the new transmit structure with the training data embedding secure symbols for distinguishing authorized users and the eavesdroppers. This solution is so-called security on the physical level which is considered as the robust solution for processing by the traditional software. In this investigation, we also focus on normalized mean square error (NMSE) analysis for different performance of two types of users mentioned. Simulation results confirm our modified scheme and illustrate that the semi-blind channel estimation with embedded secure data is capable of improving the security of the overall system.

GPS multipath reflectometry (GPS-MR) is a technique that uses geodetic quality GPS receivers to estimate snow depth. The accuracy and precision of GPS-MR retrievals are evaluated at three different sites: grasslands, alpine, and forested. The assessment yields a correlation of 0.98 and an rms error of 6-8 cm for observed snow depths of up to 2.5 m. GPS-MR underestimates in situ snow depth by 10%-15% at these three sites, although the validation methods do not measure the same footprint as GPS-MR.

We present closed-form expressions for the average bit error probability (ABEP) of BPSK, QPSK and M -QAM of an amplify-and-forward average power scaling dual-hop relay transmission, over non-identical Nakagami-m fading channels, with integer values of m. Additionally, we evaluate in closedform the ABEP under sufficiently large signal-to-noise ratio for the source-relay link, valid for arbitrary m. Numerical and simulation results show the validity of the proposed mathematical analysis and point out the effect of the two hops unbalanced fading conditions on the error performance.

GENZ, A.S.; FLETCHER, C.H.; DUNN, R.A.; FRAZER, L.N., and ROONEY, J.J., 2007. The predictive accuracy of shoreline change rate methods and alongshore beach variation on Maui, Hawaii. Journal of Coastal Research, 23(1), 87-105. West Palm Beach (Florida), ISSN 0749-0208.

We present a spectroscopic analysis of HST/STIS and FOS low-and intermediate-resolution spectroscopy of 55 stars in four globular clusters (47 Tucanae, M 3, NGC 6752, and NGC 6397). Stars hotter than T eff = 5750 K and with a signal-to-noise ratio larger than 15 were analyzed with non-Local Thermodynamic Equilibrium model atmospheres, and values for their effective temperatures and gravities were obtained. Using photometric fluxes, we also obtained radii, luminosities and spectroscopic masses.

A new high-resolution recording device for transmission electron microscopy (TEM) is urgently needed. Neither film nor CCD cameras are systems that allow for efficient 3-D high-resolution particle reconstruction. We tested an active pixel sensor (APS) array as a replacement device at 200, 300, and 400 keV using a JEOL JEM-2000 FX II and a JEM-4000 EX electron microscope. For this experiment, we used an APS prototype with an area of 64  64 pixels of 20 mm  20 mm pixel pitch. Single-electron events were measured by using very low beam intensity. The histogram of the incident electron energy deposited in the sensor shows a Landau distribution at low energies, as well as unexpected events at higher absorbed energies. After careful study, we concluded that backscattering in the silicon substrate and reentering the sensitive epitaxial layer a second time with much lower speed caused the unexpected events. Exhaustive simulation experiments confirmed the existence of these back-scattered electrons. For the APS to be usable, the backscattered electron events must be eliminated, perhaps by thinning the substrate to less than 30 mm. By using experimental data taken with an APS chip with a standard silicon substrate (300 mm) and adjusting the results to take into account the effect of a thinned silicon substrate (30 mm), we found an estimate of the signal-to-noise ratio for a back-thinned detector in the energy range of 200-400 keV was about 10:1 and an estimate for the spatial resolution was about 10 mm. r

Exchange spring media are proposed for magnetic-recording systems consisting of a hard/soft bilayer. By varying the fraction of thickness for the hard and soft layer and by varying their saturation polarizations, the media properties can be optimized in order to achieve high thermal stability without increase of coercive field. In grains with identical size and coercivity, an optimized bilayer reaches an energy barrier exceeding those of optimized single-phase media by more than a factor of two. Thus, exchange spring media allow to reduce the grain diameter by more than a factor of 1 2. Additionally, the lower angular dependence of coercivity of exchange spring media improves the signal-to-noise ratio (SNR) by a factor of 2 5.

We present an approach for separating two speech signals when only one single recording of their linear mixture is available. For this purpose, we derive a filter, which we call the soft mask filter, using minimum mean square error (MMSE) estimation of the log spectral vectors of sources given the mixture's log spectral vectors. The soft mask filter's parameters are estimated using the mean and variance of the underlying sources which are modeled using the Gaussian composite source modeling (CSM) approach. It is also shown that the binary mask filter which has been empirically and extensively used in single channel speech separation techniques is, in fact, a simplified form of the soft mask filter. The soft mask filtering technique is compared with the binary mask and Wiener filtering approaches when the input consists of male+male, female+female, and male+female mixtures. The experimental results in terms of signal-to-noise ratio (SNR) and segmental SNR show that soft mask filtering outperforms binary mask and Wiener filtering.

A joint sampling-time error and channel skew background calibration technique for time interleaved analog to digital converters (TI-ADC) is presented. The technique is aimed at applications in dual-polarization QPSK/QAM receivers for coherent optical communications at high data rates (e.g., 40Gb/s and beyond). Unlike previous proposals, the calibration algorithm introduced here is used to jointly compensate for samplingtime and channel skew errors. Estimates of the gradient of the mean squared error (MSE) or the bit error rate (BER) with respect to the sampling phases of the different signal lanes and interleaves are computed and used to iteratively minimize a cost function (i.e., MSE or BER). Computer simulations demonstrate the excellent behavior of the proposed compensation technique. The calibration algorithm can be implemented with minimal hardware requirements and with a slow clock. This allows power dissipation in a CMOS VLSI implementation to be minimized.

We study the role of multiplicative colored noise for different values of the correlation time τc in the dynamics of two competing species, described by generalized Lotka-Volterra equations. The multiplicative colored noise models the interaction between the species and the environment. The interaction parameter between the species is a random process which obeys a stochastic differential equation with a generalized bistable potential in the presence of a periodic driving term, which accounts for the environment temperature variation. The bistable potential is useful to describe the coexistence and exclusion dynamical regimes of the ecosystem. Noise-induced periodic oscillations of the species concentrations and stochastic resonance phenomenon appear due to the presence of the multiplicative noise. We find that for low values of the correlation time τc the response of the system coincides with that obtained with multiplicative white noise. For higher values of τc the coherent response of the system and the maximum of the signal-to-noise ratio, signature of the stochastic resonance phenomenon, are shifted towards higher values of the noise intensity.

Wireline transceivers for high-speed data transmission through backplane and ethernet cables are important applications for microelectronic and nanoelectronic CMOS technologies. Although many circuit simulators provide correct system-level and transistor-level simulations, they usually fail to give correct results for many highly lossy or/and highly dispersive channels. This paper discusses the advanced simulator that we developed. It can give correct simulation results

A sensitive, precise and accurate method has been developed for the simultaneous determination of T-2 and HT-2 toxins in cereal grains at ppb levels using high-performance liquid chromatography (HPLC) with fluorescence detection and 1-antroylnitrile (1-AN) as labeling reagent after immunoaffinity clean-up. Cereal samples were extracted with methanol/water (90:10, v/v), and the extracts were cleaned-up through commercially available immunoaffinity columns containing

This paper presents analysis of a digital Ultrawideband (UWB) radio receiver operating in the 3.1 GHz to 10.6 GHz band. Analog to digital converter (ADC) bit precision is analyzed on two types of UWB signals -OFDM UWB and pulsed UWB -all in the presence of Additive White Gaussian Noise (AWGN) and a narrowband interferer in the channel. This paper shows how probability of error and the bit resolution of the ADC can be scaled depending on the Signal to Noise Ratio (SNR), Signal to Interference Ratio (SIR), and the type of UWB signal. It also includes considerations on timing recovery for pulsed UWB.

Downstream (DS) crosstalk channels of digital subscriber line systems can be estimated based on the reported signal-to-noise ratio (SNR). In the case of an already active victim line (VL) impacted by the joining of a new disturber line (DL), sending perturbing signals on the VL and reporting the SNRs allow the estimation of the crosstalk channel from the DL to the VL. This paper generalizes that concept to include full startup, tracking and joining scenarios as well as the impact of different perturbation signal choices. Additionally, the sensitivity of the algorithm to different sources of imperfection is analyzed. Simulation results reveal that starting without precoding, and updating the precoder matrix based on the DS crosstalk channel estimates, the far-end crosstalk-free SNR can be reached in a limited number of iterations (e.g., 36 SNR measurements are needed for the four lines case). The SNR-assisted method is documented in an informative appendix of the draft G.vector recommendation as a backward compatible method for very high speed digital subscriber lines (VDSL2) and, hence, can be used for channel acquisition today.

Position sensors other than the R/W heads are not embedded into current hard-disk drives (HDDs) due to cost, resolution, and signal-to-noise ratio (SNR) issues. Moreover, the "optimal" location for placing these sensors is still unknown. In this paper, the Pb-Zr-Ti (PZT) elements in the PZT suspension-based microactuator are used as a secondary actuator and a displacement sensor simultaneously with self-sensing actuation. The proposed displacement estimation circuit produces an estimated PZT microactuator's displacement with high SNR and nanometer resolution comparable to that measured from the laser doppler vibrometer (LDV). A robust active mode damping controller is then designed to damp the PZT microactuator suspension's torsion modes and sway mode, as well as decoupling the HDD dual-stage servo into two distinct loops for individual sensitivity optimization. Our results show attenuation of PZT microactuator's suspension modes by 5 dB and sway mode by 30 dB with low sensitivity. A reduction of up to 20% in 3σ position error signal is also observed.

We propose to use a kernel intensity penalizer (KIP) in the blind maximum likelihood expectation maximization (MLEM) deconvolution scheme. With this very general kernel regularization term, we can stabilize the blind MLEM scheme even for the deconvolution of wide-field microscopic recordings. No complex prior point spread function models are needed. We combine state of the art optimization schemes using Tikhonov-Miller and TV regularization with our new kernel regularization. The proposed method improves the conventional deconvolution methods in terms of SNR on real and simulated datasets.

Techniques based on impulsive sources are used since the beginning of the Underwater Acoustic science, to evaluate the distance of objects and to plot the profile of the sea bottom. In this paper the authors investigate the behavior of three not-impulsive techniques for the measurement of impulse responses: MLS (Maximum Length Sequence) signal, linear sine sweep and logarithmic sine sweep. This work will focus the attention on advantages and defects of these tree different methods, in comparison with the traditional pulse-based sonar techniques. The mathematical theory for the generation of the MLS, sine sweep signals and for the deconvolution of the system's impulse response are first described. Then a software implementation of the measurement methods, based on the creation of plug-ins for a shareware waveform editor, running on a low cost PC is demonstrated. Some experiments conducted under controlled conditions and in the sea show that the proposed techniques produce images of the bottom profile with higher signal-to-noise ratio and better spatial resolution than those obtainable with the impulsive technique. Moreover signal-to-noise ratio increases using sine sweep signal instead of MLS one. The new techniques seem superior also for some practical aspects connected with their very nature, which make them almost inaudible and makes the sound source barely localizable: this is very important for military applications.