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Currently, the widely used methods for direction of arrival (DOA) estimation were constructed based on the subspace, such as Multiple Signal Classification (MUSIC) and Estimating Signal Parameter via Rotational Invariance Techniques (ESPRIT), which required that the number of sources is known beforehand. In this paper, a new method based on the Vector Error Model (VEM) for estimating the DOAs was proposed, which do not need the sources number in advance. The comparison of the performance between the VEM and the MUSIC model for DOA problem was given to demonstrate the effectiveness of our method. The algorithm of multi-target intermittent particle swarm optimization (MIPSO) was adopted to solve the VEM, and the performance of the VEM-MIPSO method was analysed through simulations for a uniform linear array and an L-shaped array respectively. The results showed that: (1) the VEM was an effective model to solve the DOA estimation without prior knowledge of the sources number; (2) the MIPSO was an efficient algorithm to solve the DOA estimation with high precision.

Geomechanical model test is an important way to analyze the safety of high arch dams. The traditional monitored displacements and stresses are difficult to interpret the internal failure process of dams and foundations. Acoustic emission(AE) technique was used in the geomechanical model test of arch dam to analyze its internal failure. AE 2D planar locating technology for arch dams and signal parameter analysis method were studied and applied to an arch dam geomechanical model test. The failure process of the dam body and foundation was revealed. The left dam heel of the arch dam model cracked first, continuing to expand to higher elevation along the left abutment with the increase of overload times, and the horizontal crack penetration leaded to the ultimate failure of the dam body. Safety factors for initial crack, nonlinear deformation and ultimate bearing capacity of the arch dam model had been clearly obtained based on AE technique. The results of AE analysis coincided well with the actual failure condition. So it is confirmed that AE technique is effective for geomechanical model test, and it has a bright prospect to be used in situ test of arch dam.

In the article analyzes the issues of ensuring the safety of the most stressed and critical components and parts and the theoretical aspects of diagnostics using electromagnetic-acoustic wave phenomena, provides a general expression for the instantaneous mechanical stress $\sigma\mathrm{m}$ acting on the surface of a layered medium, a complex of diagnostic parameters for determining the technical condition of metal elements of power equipment; algorithms for determining the technical condition of metal elements of power equipment; methods for assessing the safe operation resource of technological equipment by signal parameter values.

Spherical arrays have been widely used in direction-of-arrival estimation in recent years, and most algorithms in the spherical harmonics domain typically simultaneously obtain the 2-D angles. In this paper, we first use the structured least squares (SLS) to improve the performance of the decoupled spherical harmonics estimation of the signal parameter via rotational invariance technique (D-SHESPRIT) and propose D-SHESPRIT-SLS. Second, we derive the mean square error of the proposed algorithm and compare estimated results with theoretical results. The simulation results demonstrate the satisfactory performance of the proposed method.

Acoustic emission is one of the effective techniques used for the condition monitoring of rolling element bearings. Contamination is one of the major reasons for bearing early failure due to presence of solid particle in lubricant grease. In most cases, outer race is stationary and the inner race is attached to the rotating assembly. The lubrication is very essential for the bearing to perform under various demanding conditions. The main aim of this project is to analyze the effect of contamination of lubricant by solid particles on the dynamic behavior of rolling bearing. Green sand at three concentration levels 5%, 15%, 25% and different particle sizes 75 μm, 106 μm and 150μm is used to contaminate the lubricant. Experimental tests have been performed for different load and speed condition in good and contaminated ball bearings lubricated with grease. The trends in the amount of AE waves affected by the contamination of the grease were determined. Acoustic emission signals were analyzed in terms of RMS, kurtosis, and peak-peak.

A parameter extraction method to determine the parameters of small signal equivalent circuit model for PIN photodiodes is proposed in this study, which combines the analytical approach and the empirical optimisation procedure. The equations used for extraction and the extracted parameters of circuit elements are presented. Good agreement is obtained between the simulated and measured S -parameters up to 40 GHz.

In this paper, a one-step method is proposed for the classification and estimation of the parameters in the scenario of mixed near-field and far-field stationary sources. By constructing several temporal-spatial cumulant matrices, utilizing the stationary property of sources, and introducing a mechanism for controlling the rank, a parameters estimation matrix is formed. This matrix contains electric angles and signals information. By introducing a method based on the rotational invariant technique and using the estimation signal parameter, the direction-of-arrival of all sources' signals and the range of the near-field sources (NFSs) are estimated. Also, a reasonable classification of the signals types is provided. Unlike conventional methods, the proposed method does not require any spectral search stage, so it reduces the computational complexity to a great extent. The proposed algorithm prevents the array aperture loss, has no need to know the number of NFSs or field-field sources, and does not require any extra stage to pair the parameters. Mathematical analysis and simulation results validate the good performance of parameters estimation and sources classification in the proposed method.

In this letter, we propose a method to extract the small-signal equivalent circuit model for GaN HEMTs using extrinsic-level RF broadband (0.5–50 GHz) Z-parameters. The measured Z-parameters of large gate-periphery GaN devices exhibit certain interesting characteristics, due to their inherently larger intrinsic capacitances and their subsequent interaction with the extrinsic inductances. We exploit these characteristics to simultaneously extract the intrinsic as well as the extrinsic small-signal model components and successfully validate it with measured S-parameter data for a $10~\times90~\mu \text{m}$ GaN device.

The Adaptive Quantization is proposed-an algorithm for generating sinusoidal signal samples for a digital-controlled measuring oscillator. Adaptive quantization significantly improves the selected signal parameter, for example, the error of the first harmonic, reduces the dependence of the parameter on the sampling frequency, reduces the requirements for the DAC.

Currently, the widely used methods for direction of arrival (DOA) estimation were constructed based on the subspace, such as Multiple Signal Classification (MUSIC) and Estimating Signal Parameter via Rotational Invariance Techniques (ESPRIT), which needed to know the number of sources in advance. In this paper, a new model based on the Generalized Reference Curve Model (GRCM) for the DOA estimation was proposed, which do not need to know the sources number in advance. And the comparison of the performance between the proposed model and the MUSIC model was given to demonstrate the effectiveness of our method. The algorithm of Multi-target Intermittent Particle Swarm Optimization (MIPSO) was adopted to solve the model proposed in this paper, and the performance of the MIPSO was analyzed through a simulation. The result shown that:(1) the GRCM was an effective model to solve the DOA estimation without prior knowledge of the sources number; (2) the MIPSO was an efficient algorithm to solve the DOA estimation with much shorter operation time and high precision.

The study is devoted to a perspective diagnostic method, which makes it possible to deal with diagnostic tasks – the acoustic non-destructive inspection method based on acoustic emission (AE) signal parameter analysis. The practical use of this method is related to the interpretation of diagnostic measurement data. The parameters of acoustic emission (AE) signals were measured during bench tests of the tail boom structure and fin, as well as the joint areas of the fin, tail boom, and fuselage of the helicopter (joint area No.1 and No.19, frames of the tail boom and fuselage respectively).The analysis of fatigue damage kinetics was carried out in several stages for groups of bolts and for characteristic structure loading intervals. Bolt fracture was predicted at least 26 to 44 flight hours before the actual collapse. Using the AE parameters, the micro crack origin intervals identified when the bolt bearing capacity after the occurrence of the damage reached 96%.

RFID is a technology allowing tracking objects or people and mainly applied in critical applications including industrial control, personnel access, etc… Nowadays, demands for providing positional information has grown rapidly and RFID positioning technique is emerging especially for an indoor locating as its development and implementation are very fast. WSN gives information about the objects physical conditions that permit to create cost effective services adapted to application needs. Thus, RFID and WSN integration is an emerging technology utilizing both systems advantages making it reliable and efficient. In this paper, we propose real time locating techniques to satisfy the request of mobile expensive medications localization and managing in a hospital environment efficiently using AOA and TOA based on received signal parameter. We implemented WSN and RFID architectures and discussed it by specifying advantages and disadvantages for indoor real time positioning in our healthcare application.

The paper is devoted to the development of an algorithm for resolution and parameter estimation of radio impulses with partially overlapping spectra in the area of their nonorthogonality (the correlation coefficient varies from 0 to 0.9). The implementation of the suggested algorithm makes it possible to design filters for resolving frequency-dependent signals and, therefore, to increase the capacity of a communication channel. The maximum likelihood method has been used to obtain analytical expressions and to perform model investigations for frequency resolution of nonorthogonal signals. The dynamic range of signal parameter estimates has been found as a function of signal-to-noise ratio and correlation coefficient. It has been shown that the likelihood functional value in its global minimum allows one to estimate noise variance and the number of radio impulses in a received signal.

In today's complex battlefield environment, the interference signal parameter identification is the key to distinguish the interference signals, and the basis of winning information warfare. This paper first introduces the five traditional characteristic parameters that must be extracted in the signal sorting, and introduces the extraction methods and steps of the five parameters in detail. Then, from the point of distinguishing the parameter invariant signals and the parameter agile signals, presents two common signal sorting algorithms. Finally, the content of this paper is summarized.

Spherical arrays have become a popular research topic in recent years because of their advantages in direction-of-arrival (DOA) estimation. In this paper, we develop a two-stage method (TSM) based on spherical arrays to estimate DOAs of source signals. First, we propose a novel spherical harmonics estimation of signal parameter via rotational invariance technique that independently obtains the elevation using one recurrence relation of spherical harmonics (SHESPRIT-ELE). Second, we utilize spherical harmonics root-MUSIC, which can only obtain the azimuth with a determined elevation, to estimate the azimuth based on the elevation obtained in the first stage (SHRMUSIC-AZI). The proposed TSM owns high estimation accuracy and low computational complexity. The simulation results verify the performance of the proposed method.

Algorithm of radio thermal signal processing in the radiometer, which is characterized by unstable gain in predetection section of receiver, is given. This algorithm compares with signal processing algorithm in Dicke radiometer. Differences in the signal processing are indicated and the statistical characteristics of the radio-brightness temperatures estimations are compared, and the fluctuation sensitivity of the receivers. The conditions are grounded with which the application of the new type modulation radiometer is the most expedient.

We use S-Parameter Methodto extract device parameter of InAlN/GaN HEMT in this paper. We find thatparasitic capacitance and parasitic inductance can be extracted in traditionaltest structure method, but do nothing about parasitic resistor. Cold parameter methodcan extract parasitic resistor efficiently, but there is greater error inparasitic capacitance and parasitic inductance extraction. We propose a methodwhich combines test structure method and cold parameter method to extract parasitic parameteraccurately. We can acquire intrinsic parameters through getting rid ofparasitism parameters, and can fitting test outcome satisfactorily. It canreflect accurately the physical characteristics of GaN HEMT devices, and givesfeedback and guidance to device technology at the same time.

In this work, an acoustic emission monitoring experiment of a tank floor plate was conducted in a laboratory simulation of practical production conditions. In addition to analysis of the corrosion mechanism, emission signals were collected in experiments using acoustic emission signal parameter analysis, and the acoustic emission characteristics of the tank floor corrosion process were obtained under different working conditions. Thus this chapter provides a basis for acoustic emission testing and evaluation in the field, with improved reliability.

Although the phase difference method, proposed in the previous work by Jeong, can be a very useful signal parameter for investigating fretting behavior as well as distinguishing the fretting regime...

A certain algorithm and hardware implementation used to measure current and voltage parameters in electric generator during excitation are considered. As is generally known, measurement time for these parameters plays a crucial role. Until recently, the performance of such devices has been limited by frequency of the generated voltage (50 Hz). The paper presents an algorithm and hardware implementation of the parameter measuring-predicting device which possesses higher performance.

Acoustic communication often mediates agonistic interactions in territo- rial species. Because both the reaction to potential intruders and the lack thereof are costly, mechanisms that allow recognition of conspecific sig- nals should be evident in intrasexual communication systems. While the spectral domain of the recognition space of the frog Allobates femoralis appears asymmetrically shaped in a way that reduces masking interfer- ence by the often syntopic frog Ameerega trivittata, frequency alone does not appear to account for the correct identification of conspecific intrud- ers (Amezquita et al., Animal Behaviour, 70, 2005: 1377). As signal rec- ognition may rely on a combination of spectral and temporal parameters of the signal, we test here the subsequent prediction that the recogni- tion space should be asymmetrical in the temporal domain as well. We conducted playback experiments with 80 synthetic calls on 30 males and modeled all-or-none responses to define unidimensional functions of the recognition space for two call parameters: note duration and in- ternote interval. For both parameters, male maximal response matched very well the average values of the conspecific signal and decreased with concomitant deviations from these values. While the response curves exceeded the range of signal variation and were not asymmetri- cal for either call parameter, they differed in breadth. The highest male permissiveness to variation in internote interval, as evidenced by a broader response curve, coincided with the lower probability of between-species overlap in this signal parameter. Together with previous studies, our data suggest that a combination of spectral and temporal parameters of the advertisement call is necessary for recognition of call- ing intruders in A. femoralis. Our results emphasize the importance of multidimensional approaches in understanding signal recognition mech- anisms in acoustically complex environments.

An automatic pairing joint direction-of-arrival (DOA) and frequency estimation is presented to overcome the unsatisfactory performances of estimation of signal parameter via rotational invariance techniques- (ESPRIT-) like algorithm of Wang (2010), which requires an additional pairing. By using multiple-delay output of a uniform linear antenna arrays (ULA), the proposed algorithm can estimate joint angles and frequencies with an improved ESPRIT. Compared with Wang’s ESPRIT algorithm, the angle estimation performance of the proposed algorithm is greatly improved. The frequency estimation performance of the proposed algorithm is same with that of Wang’s ESPRIT algorithm. Furthermore, the proposed algorithm can obtain automatic pairing DOA and frequency parameters, and it has a comparative computational complexity in contrast to Wang’s ESPRIT algorithm. By the way, this proposed algorithm can also work well for nonuniform linear arrays. The useful behavior of this proposed algorithm is verified by simulations.

In this paper, we propose an Estimation of Signal Parameter via Rotational Invariance Techniques (ESPRIT) based algorithm for estimating the two-dimensional-direction-of-arrivals (2D-DOA) of signals impinging on a uniform rectangular array (URA). The basic idea of the proposed algorithm is to successively apply two rounds of one-dimensional ESPRIT (1D-ESPRIT) algorithm for 2D-DOA estimation. The first round 1D-ESPRIT is applied on columns of the URA whereas the other round 1D-ESPRIT is on the rows of the URA. In between, a grouping technique is developed to produces signal groups each containing signals with distinguishable spatial signatures. The grouping technique is performed by using the subspace projection method where the needed spatial information is provided by the first round 1D-ESPRIT algorithm. Computer simulations show that, in addition to having significantly reduced computational complexity, the proposed algorithm possesses better estimation accuracy as compared to the conventional 2D-ESPRIT algorithm.

In this paper, we present a new method for multi-scale analysis of electromyography signals based on an interesting fractal process known as multiplicative cascade multi-fractal. Using simulated needle electromyography signals, we show this method provides a means for discrimination of normal and neuropathic electromyography signals. We also present experimental results that show the new parameters, computed using multiplicative cascade multi-fractal modeling, are more robust than the conventional signal parameter, number of turns, in the presence of additive noise. Results of multiplicative cascade multi-fractal modeling are consistent with other multi-scale approaches; advantages and differences are high lighted.

The methodological aspects and results of experimental studies allowing for remote evaluation of the integrity of structural materials under loading using the method of electromagnetic emission (EME) are considered. It is known that in the process of loading different materials systems of cracks that are formed in them emit acoustic and electromagnetic signals. Based on signal parameter variations, it is possible to predict an oncoming moment of disruption of their integrity. The EME is a remote method and does not require direct contact with an object under study, be it rock specimens or metal articles. It is proposed to use it for testing the integrity of metal articles. The first results of diagnostics of the integrity of metal rings made of different materials (steels, duraluminum, zirconium, and copper) using sensing devices, namely antennas of electrical and magnetic types, are presented. It is shown that when loaded different types of materials emit EME signals of different amplitudes whose level substantially exceeds the level of external disturbances and internal equipment noises. It is proposed to evaluate the integrity of different metal articles, especially those in nooks, based on increased amplitudes of EME signals.

We investigate the phenomenon of stochastic resonance (SR) in parallel integrate-and-fire neuronal arrays with threshold driven by additive noise or signal-dependent noise (SDN) and a noisy input signal. SR occurs in this system. Whether the system is subject to the additive noise or SDN, the input noise [Formula: see text] weakens the performance of SR but the array size N and signal parameter [Formula: see text] promote the performance of SR. Signal parameter [Formula: see text] promotes the performance of SR for the additive noise, but the peak values of the output signal-to-noise ratio [Formula: see text] first decrease, then increase as [Formula: see text] increases for the SDN. Moreover, when [Formula: see text] tends to infinity, for the SDN, the curve of [Formula: see text] first increases and then decreases, however, for the additive noise, the curve of [Formula: see text] increases to reach a plain. By comparing system performance with the additive noise to one with SDN, we also find that the information transmission of a periodic signal with SDN is significantly better than one with the additive noise in limited array size N.

A field study of disputes over ownership of mating territories by male tarbush grasshoppers (Ligurotettix planum) revealed that most contests were settled ritualistically via the antiphonal exchange of acoustic signals. Males used a special aggressive signal, referred to as the “shuck” call, in these encounters. Individuals that never produced shuck calls invariably departed the contested sites, and a playback experiment showed that shuck calls elicited higher response levels from males than sexual advertisement calls. Approximately 1/5 of all territorial contests escalated to biting, grappling, or kicking. The outcomes of territorial contests that were settled via purely acoustic encounters could not be predicted by the size of the participants. Prior residency was a predictor of winning in some contests, but often the competing males did not possess clear intruder/resident roles. However, a signal parameter that was a combined measure of the rate of shuck calls and their mean length predicted the winner of most acoustic encounters. Contests that escalated, though, were generally distinguished by participants that displayed comparable measures of all signal parameters save call length. A tradeoff occurred between call rate and length in most individuals. This, as well as the finding that call length did predict winning in escalated contests, implies that these signal parameters may reflect an individual's strength or motivation. Contests in which the signal parameters of the males were similar tended to be prolonged and escalated. This relationship suggests that individuals assess the signals of their rivals and depart if they cannot match their call rate and length. That both call rate and length are assessed may enhance the reliability with which signals can be used to predict a rival's fighting ability in the event of escalation. Various simple mechanisms for signal assessment are proposed. A second playback experiment suggested that the insects heard less effectively while they called. Timing mechanisms that preclude the overlap of calls during contests occur, and they may have evolved because of the importance of precise assessment of the signals of rivals. Such mechanisms circumvent the potential impairment in perception noted above and also generate a conspicuous feature of L. planum contests — mutual alternation of signals.

A microbial biosensor analyzer for determination of the biological oxygen demand index was made and appraised. A mixed culture of bacteria of the genus Pseudomonas immobilized in an agar gel was a biologically sensitive element of the biosensor system; a transducer was an amperometric system of the Clark’s electrode, the maximum value of the variation of oxygen concentration in the measurement medium was the signal parameter being measured. The working characteristics of the microbial biosensor analyzer as well as the conditions of determinations and the algorithm of computing the biological oxygen demand index were elaborated on real objects of technogenic waters.

Background and Purpose— Gradient recalled echo MRI (GRE) has been shown to be as accurate as CT for the detection of acute intracerebral hemorrhage (ICH). However, because of the differences in the signal parameter being detected, apparent hemorrhage size is expected to vary by imaging modality, with GRE providing larger volumes attributable to susceptibility effects. Methods— Image data from patients participating in 3 ICH studies were retrospectively reviewed. Patients with acute ICH were included if (1) concurrent MRI and CT were performed within 72 hours of symptom onset, and (2) each modality was performed within 240 minutes of each other. ICH volumes were calculated using a semiautomated image analysis program. The least squares method was used to develop a conversion equation based on a linear regression of GRE volume on CT volume. Results— Thirty-six patients met inclusion criteria. MRI was performed first in 18, CT first in 18. Mean hemorrhage volume was 25.2cc (range 0.1 to 83.9cc) on CT and 32.7cc (range 0.1 to 98.7cc) measured on GRE. A linear relationship defined by CT Volume=GRE Volume*0.8 (Spearman’s correlation coefficient=0.992, P Conclusions— Acute ICH volumes as measured on GRE pulse sequences are consistently larger than CT volumes. A simple mathematical conversion model has been developed: CT volume=0.8*GRE volume. This formula can be used in studies using both imaging modalities, across different studies, or to track ICH growth over time independent of imaging modality in an individual patient.

The presence of sodium deposits in defective regions of steam generator (SG) tubes of fast-breeder reactors is expected to influence the remote field eddy current (RFEC) signals. By exposing five SG tubes having uniform wall loss grooves to a sodium environment in a specially designed test vessel, changes in the shape of RFEC signals were observed and it was possible to approximate the volume of sodium deposited in defects. An invariant signal parameter was determined for quantitative characterization of defects despite the presence of sodium in the defects.

The changes in echolocation behaviour and the structure of calls ofPipistrellus pygmaeus (Leach, 1825) were studied in different habitats of a floodplain forest in south-eastern Moravia (Czech Republic) in 2001–2002. Calls (403 observations) were recorded in different sites between April and mid June (before weaning) using a time expansion bat-detector. Three signals per individual were analysed and descriptive statistics of variables of calls were presented. Association of signal types with habitat structure (cluttered, side-cluttered, semi-cluttered and uncluttered space) was found in echolocation sequences of the search phase of flight.P. pygmaeus used mainly narrowband signals (bandwidths less than 15 kHz) in uncluttered space and wideband signals (more than 15 kHz) in cluttered space. Almost 6% of the inter pulse intervals of signals were twice (or more) longer than usual inter pulse intervals (mainly in uncluttered space). In general, temporal variables of signals reached higher values in uncluttered spaces (except for inter pulse interval) than in cluttered ones. On the contrary, spectral variables of signals reached lower values in uncluttered habitats in comparison with cluttered ones. In addition, the signals were less variable in open spaces while in cluttered and partly-cluttered habitats different and higher variability was found. We also studied the accuracy of identification of pipistrelles by call parameters and possible misidentifications in relation to habitat structure. Multivariate discriminant analyses were carried out on the time and frequency parameters of calls produced by pipistrelles.

The paper reports on basic underlying principles of methods for evaluating the danger degree of fatigue cracks in the acoustic emission (AE) testing of cast pieces of freight-car trucks on the basis of statistical dependences of the AE signal parameters in the aw development stage.

A novel efficient method for two-dimensional (2D) direction-of-arrivals (DOAs) estimation is proposed to reduce the computational complexity of conventional 2D multiple signal classification (2D-MUSIC) algorithm with uniform rectangular arrays (URAs). By introducing two electrical DOAs, the formula of 2D-MUSIC is transformed into a new one-dimensional (1D) quadratic optimal problem. This 1D quadratic optimal problem is further proved equivalent to finding the conditions of noise subspace rank deficiency (NSRD), which can be solved by an efficient 1D spectral search, leading to a novel NSRD-MUSIC estimator accordingly. Unlike 2D-MUSIC with exhaustive 2D search, the proposed technique requires only an efficient 1D one. Compared with the estimation of signal parameter via rotation invariance techniques (ESPRIT), NSRD-MUSIC has a significantly improved accuracy. Moreover, the new algorithm requires no pair matching. Numerical simulations are conducted to verify the efficiency of the new estimator.

[ES] Este trabajo propone la detección de FV y su discriminación de TV y otros ritmos cardiacos basándose en la representación tiempo-frecuencia del ECG y su conversión en imágen como entrada a un clasificador de vecinos más cercanos (KNN) sin necesidad de extracción de parámetros adicionales. Tres variantes de datos de entrada al clasificador son evaluados. Los resultados clasifican la señal en cuatro clases diferentes: ’Normal’ para latidos con ritmo sinusal, ’FV’ para fibrilación ventricular, ’TV’ para taquicardia ventricular y ’Otros’ para el resto de ritmos. Los resultados para detección de FV mostraron 88,27% de sensibilidad y 98,22% de especificidad para la entrada de imágen equivalente reducida que es la más rápida computacionalmente a pesar de obtener resultados de clasificación ligeramente inferiores a las representaciones no reducidas. En el caso de TV, se alcanzó un 88,31% de sensibilidad y 98,80% de especificidad, un 98,14% de sensibilidad y 96,82% de especificidad para ritmo sinusal normal y 96,91% de sensibilidad con 99,06% de especificidad para la clase ’Otros’. Finalmente, se realiza una comparación con otros algoritmos., [EN] This work describes new techniques to improve VF detection and its separation from Ventricular Tachycarida (VT) and other rhythms. It is based on time-frequency representation of the ECG and its use as input in an automatic classifier (K-nearest neighbours - KNN) without any further signal parameter extraction or additional characteristics. For comparison purposes, three time-frequency variants are analysed: pseudo Wigner-Ville representation (RTF), grey-scale image obtained from RTF (IRTF), and reduced image from IRTF (reduced IRTF). Four types of rhythms (classes) are defined: ’Normal’ for sinus rhythm, ’VT’ for ventricular tachycardia, ’VF’ for ventricular fibrillation and ’Others’ for the rest of rhythms. Classification results for VF detection in case of reduced IRTF are 88.27% sensitivity and 98.22% specificity. In case of VT, 88.31% sensitivity and 98.80% specificity is obtained, 98.14% sensitivity and 96.82% specificity for normal rhythms, and 96.91% sensitivity and 99.06% specificity for other rhythms. Finally, results are compared with other authors.

Article contains results of signal parameter research depend on increase crack length. Analysis methods of signal parameter resistance to external influences and signals clustering from crack propagation and mechanical influences are described in this paper.

The hot-carrier (HC) effect in high-k/metal-gate nMOSFETs is characterized using radio-frequency (RF) small-signal parameter analysis. To explain a novel HC degradation of RF small-signal parameters, we propose a modified surface channel resistance model that can be applied to not only conventional SiO2/poly-Si-gate nMOSFETs but also high-k/metal-gate nMOSFETs.

Although communication signals often vary continuously on the underlying signal parameter, they are perceived as distinct categories. We here report the opposite case where an electrocommunication signal is encoded in four distinct regimes, although the behavior described to date does not show distinct categories. In particular, we studied the encoding of chirps by P-unit afferents in the weakly electric fish Apteronotus leptorhynchus. These fish generate an electric organ discharge that oscillates at a certain individual-specific frequency. The interaction of two fish in communication contexts leads to the emergence of a beating amplitude modulation (AM) at the frequency difference between the two individual signals. This frequency difference represents the social context of the encounter. Chirps are transient increases of the fish's frequency leading to transient changes in the frequency of the AM. We stimulated the cells with the same chirp on different, naturally occurring backgrounds beats. The P-units responded either by synchronization or desynchronization depending on the background. Although the duration of a chirp is often shorter than a full cycle of the AM it elicits, the distinct responses of the P-units to the chirp can be predicted solely from the frequency of the AM based on the static frequency tuning of the cells.

An improved HBT small-signal parameter extraction procedure is presented in which all the equivalent circuit elements are extracted analytically without reference to numerical optimization. Approximations required for simplified formulae used in the extraction routine are revised, and it is shown that the present method has a wide range of applicability, which makes it appropriate for GaAs and InP-based single and double HBTs. Additionally, a new method is developed to extract the total delay time of HBTs at low frequencies, without the need to measure h/sub 21/ at very high frequencies and/or extrapolate it with -20 dB/dec roll-off. The existing methods of finding the forward transit time are also modified to improve the accuracy of this parameter and its components. The present technique of parameter extraction and delay time analysis is applied to an InGaP/GaAs DHBT and it is shown that: (1) variations of all the extracted parameters are physically justifiable; (2) the agreement between the measured and simulated S- and Z-parameters in the entire range of frequency is excellent; and (3) an optimization step following the analytical extraction procedure is not necessary. Therefore, we believe that the present technique can be used as a standard extraction routine applicable to various types of HBTs.