Search

The article presents an approach to train traffic modelling that allows for the analysis of how railway networks respond to various disturbances, including increased traffic and disturbance events. It discusses different methods of reconfiguration actions in key points of the railway network, which helps reduce delay propagation in the transport system. The 1st part covers building simulation models, which include defining infrastructure, setting train routes, configuring rolling stock, and disturbance scenarios, enabling the analysis of various disruptive events. The simulations allow for testing disturbance scenarios with minimal downtime risk without interfering with the real-world environment. The study results identified key system parameters generating the largest delays, such as platform availability, signaling, and the number of block sections. Probability density distributions for event intervals and durations were analyzed. The Kolmogorov--Smirnov test was used to confirm the fit of empirical distributions with theoretical ones, which were then implemented in the model of railway line No 271, running from Wrocław to Żmigród (Poland). As part of the reconfiguration of this railway line, new platforms were added, the time required for route setting was reduced, and the number of block sections was increased. These actions significantly reduced average delays, improved line capacity, and enhanced the robustness of the railway transport system against disturbances. The reconfiguration effectively reduced delays in areas causing significant time exceedances above 359 s, which was recognized in the Polish railway network as critical. [ABSTRACT FROM AUTHOR]

This article is the second of a series of two articles. In the first article of the series, a new K v distribution model and an experimental methodology to measure the K v distribution were introduced. In this second part, the K v distribution is integrated into a lyo-simulation tool, to more accurately predict the variability of the product temperature, primary drying time, total sublimation mass flow and Pirani signal. The K v distribution is also integrated into the graphical design space. The impact of incorporating the R p distribution is briefly discussed. The comparison of the simulation tool with actual product temperature monitoring, Pirani signal or overall sublimation flow shows very good agreement in the case studies presented. Overall, the lyo-simulation incorporating the K v distribution is a very useful tool to support industrial development, i.e. process optimization, scale assessment, technology transfer, and troubleshooting of the lyophilization process. [Display omitted] [ABSTRACT FROM AUTHOR]

Copyright of Railway Signalling & Communication Engineering is the property of Railway Signalling & Communication Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Telecommunication Engineering is the property of Telecommunication Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Machine Tool & Hydraulics is the property of Guangzhou Mechanical Engineering Research Institute (GMERI) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this paper, we present a novel hybrid method to simulate discrete stochastic reaction-diffusion models arising in biochemical signaling pathways. We study moderately stiff systems, for which we can partition each reaction or diffusion channel into either a slow or fast subset, based on its propensity. Numerical approaches missing this distinction are often limited with respect to computational run time or approximation quality. We design an approximate scheme that remedies these pitfalls by using a new blending strategy of the well-established inhomogeneous stochastic simulation algorithm and the tau-leaping simulation method. The advantages of our hybrid simulation algorithm are demonstrated on three benchmarking systems, with special focus on approximation accuracy and efficiency. [ABSTRACT FROM AUTHOR]

The injection of finite duration vibrational signals encoding information into a biomolecular wire of the polypeptide glycine1000 is investigated theoretically using molecular dynamics simulations and digital signal processing techniques. We demonstrate that the amplitude modulated signal applied to one of the C–N bonds of the molecule transmits in the two directions through the long polypeptide molecule, which is connected to gold clusters at each of its ends. A decay of the signal propagation speed is observed along with intensity decay. On the other hand, the molecular dynamics simulations show that signal transmission is completely achievable at room temperature, thus realistic transmission of signals through linear molecules can be performed. [ABSTRACT FROM AUTHOR]

For the purpose of target parameter estimation of the orthogonal frequency-division multiplexing (OFDM) radar, a high-resolution method of joint estimation on range and direction of arrival (DOA) based on OFDM array radar is proposed in this paper. It begins with the design and analysis of an echo model of OFDM array radar. Since there is no coupling between range and angle parameter estimation for a narrow-band signal, a method which exploits the data of one snapshot to estimate the range and angle of the target by means of multiple signal classification (MUSIC) based on virtual two-dimensional spatial smoothing in range and angle dimensions is devised. The proposed method is capable of joint estimating the range and DOA of the target in a high resolution under a single snapshot circumstance. Simulation experiments demonstrate the validity of the proposal. [ABSTRACT FROM AUTHOR]

Past construction research has focused primarily on the realization of tracking systems but much less on their effectiveness. Despite significant achievements, little is known about the relationship between the environmental site conditions and deployed sensors and their influence on system effectiveness. To reduce this knowledge gap, we investigate the effect of cement-based material on signal energy loss using electromagnetic simulation. We take conventional electromagnetic equations and derive equations that quantitatively describe the signal behavior influenced by cement-based material. Then, we conduct high frequency structure simulator (HFSS) simulations and use the experimental measurements for benchmark comparison with our analytical solution. Results suggest that our analytical method accurately quantifies attenuated signal loss. Also, we construct an attenuation spectrum of energy loss for cement-based material, which can serve as a reference for sensor deployment. Therefore, the method should enable quantification of the signal loss of sensors without actually deploying them or measuring signal data, which should lead to the more effective deployment of tracking sensors. [ABSTRACT FROM AUTHOR]

This paper considers the problem of recovering a structured signal from a relatively small number of noisy measurements with the aid of a similar signal which is known beforehand. We propose a new approach to integrate prior information into the standard recovery procedure by maximizing the correlation between the prior knowledge and the desired signal. We then establish performance guarantees (in terms of the number of measurements) for the proposed method under sub-Gaussian measurements. Specific structured signals including sparse vectors, block-sparse vectors, and low-rank matrices are also analyzed. Furthermore, we present an interesting geometrical interpretation for the proposed procedure. Our results demonstrate that if prior information is good enough, then the proposed approach can (remarkably) outperform the standard recovery procedure. Simulations are provided to verify our results. [ABSTRACT FROM AUTHOR]

This study presents a model reference adaptive control scheme based on reference-shaping approach. The proposed adaptive control structure includes two optimizer processes that perform gradient descent optimization. The first process is the control optimizer that generates appropriate control signal for tracking of the controlled system output to a reference model output. The second process is the adaptation optimizer that performs for estimation of a time-varying adaptation gain, and it contributes to improvement of control signal generation. Numerical update equations derived for adaptation gain and control signal perform gradient descent optimization in order to decrease the model mismatch errors. To reduce noise sensitivity of the system, a dead zone rule is applied to the adaptation process. Simulation examples show the performance of the proposed Reference-Shaping Adaptive Control (RSAC) method for several test scenarios. An experimental study demonstrates application of method for rotor control. [ABSTRACT FROM AUTHOR]

This paper presents a model that anticipates the emissions from eddy current brakes (ECBs) installed in high-speed trains. The emissions are computed in the 10 KHz–1.3 MHz range, where trackside signaling devices operate and issues related to electromagnetic compatibility have arisen, hindering ECB's promise of full deployment. The electromagnetic model provides a transfer function in the frequency domain between the nondesired harmonic currents produced by the train power supply and the subsequent radiated emissions by the ECBs at the trackside. The model includes the influence of the on-board ECB system's electric circuitry on the three-dimensional field computation of the electromagnets by a cosimulation approach (circuit and electromagnetic cross talk). After the data are postprocessed, the simulated results are compared with the results of an extensive measurement campaign on board a high-speed ICE 3 train equipped with ECBs. The high correlation makes it possible to anticipate ECB emissions in order to save costly on-track test runs, to suggest ECB design strategies and to provide safe limits when the worst cases occur. [ABSTRACT FROM PUBLISHER]

Networked systems and their control are highly important and appear in a variety of applications, including vehicle platooning and formation control. Especially vehicle platoons have been intensively investigated. An interesting problem that arises in this area is string stability, which broadly speaking means that an input signal amplifies unboundedly as it travels through the vehicle string. However, various, not necessarily equivalent, definitions are commonly used. In this paper, we aim to formalise the notion of string stability and illustrate the importance of those distinctions on simulation examples. A second goal is to extend the definitions to general networked systems. [ABSTRACT FROM AUTHOR]

Computers are widely used for educational purposes. Multimedia tools and simulations are mostly preferred for learning especially hard and complex structures in technical field and hardly realized experiments in laboratory environment. Besides, supporting theoretical knowledge with practical applications is crucial in engineering education. But, effects of negative conditions such as hardware deficiency (experimental gadgets, measuring instruments, etc.) in education environment, high number of students, less number of educators can be diminished with concepts which are distance education, computer-aided education, etc. In this study, web-based educational tool which is oriented to signals and systems subjects/courses is realized. This tool provides learning of signals and systems subjects with its subject descriptions, solved/unsolved problems, animations, simulations, interactive simulators, real-time applications, general exams, online communication/support, and new educational strategy in easy, simple, and effective way. Usability and educational contribution of realized study was inspected with questionnaires which were filled anonymously by 110 students in Uludag University and assessed according to SUS and Likert scales. [ABSTRACT FROM AUTHOR]

To make valid inferences from recurrence plots for time-delay embedded signals, two underlying key questions are: (1) to what extent does an unthresholded recurrence (URP) plot carry the same information as the signal that generated it, and (2) how does the information change when the URP gets distorted. We studied the first question in our earlier work [1] , where it was shown that the URP admits the reconstruction of the underlying signal (up to its mean and a choice of sign) if and only if an associated graph is connected. Here we refine this result and we give an explicit condition in terms of the embedding parameters and the discrete Fourier spectrum of the URP. We also develop a method for the reconstruction of the underlying signal which overcomes several drawbacks that earlier approaches had. To address the second question we investigate robustness of the proposed reconstruction method under disturbances. We carry out two simulation experiments which are characterized by a broad band and a narrow band spectrum respectively. For each experiment we choose a noise level and two different pairs of embedding parameters. The conventional binary recurrence plot (RP) is obtained from the URP by thresholding and zero-one conversion, which can be viewed as severe distortion acting on the URP. Typically the reconstruction of the underlying signal from an RP is expected to be rather inaccurate. However, by introducing the concept of a multi-level recurrence plot (MRP) we propose to bridge the information gap between the URP and the RP, while still achieving a high data compression rate. We demonstrate the working of the proposed reconstruction procedure on MRPs, indicating that MRPs with just a few discretization levels can usually capture signal properties and morphologies more accurately than conventional RPs. [ABSTRACT FROM AUTHOR]

The El Niño–Southern Oscillation (ENSO) is dominant mode of interannual climate variability, but its response to external climate forcings remains uncertain. Past studies have limitations including the use of short datasets and the uncertainty contained in reconstructions or simulations of past ENSO variations. To improve our understanding on ENSO variations, it is important to examine its response to these forcings by using multi model simulations since they provide longer datasets and help improving the statistical significance of the results. In this study, Granger causality test is applied to investigate the influence of external forcings on ENSO by using past millennium simulations (period 850–1850 CE) of Coupled Model Intercomparison Project Phase 5 (CMIP5) models. The results show robust influence of volcanic forcing to ENSO during preindustrial times of last millennium. The response of ENSO to solar forcing is more likely to be weak. Detection of GHGs variations signal in ENSO response is not significant. However, this study also indicates that there are uncertainties in the responses of ENSO to solar forcing and GHGs radiative forcing. The possibility of the true causal connection between Total Solar Irradiance (TSI) or GHGs radiative forcing and ENSO cannot be rejected at 95% significance level. [ABSTRACT FROM AUTHOR]

We propose a quantized feedback-based differential signaling scheme for $2 \times 1$ free space optical (FSO) multiple-input single-output communication systems. The analytical bit error rate (BER) for the proposed differential signaling scheme is derived and compared with the existing differential signaling scheme for FSO systems. The asymptotic BER of the proposed scheme is also determined and it is shown by using the asymptotic BER expression that the proposed scheme achieves full spatial diversity of two. Moreover, the effect of the feedback error on the performance of the proposed scheme is studied and it is demonstrated by simulation-based and analytical results that the proposed scheme significantly outperforms a previously proposed differential signaling scheme in terms of turbulence fades reduction for tolerable feedback errors. [ABSTRACT FROM AUTHOR]

The reflection of a low-mode internal tide on the Tasman continental slope is investigated using simulations of realistic and simplified topographies. The slope is supercritical to the internal tide, which should predict a large fraction of the energy reflected. However, the response to the slope is complicated by a number of factors: the incoming beam is confined laterally, it impacts the slope at an angle, there is a roughly cylindrical rise directly offshore of the slope, and a leaky slope-mode wave is excited. These effects are isolated in simulations that simplify the topography. To separate the incident from the reflected signal, a response without the reflector is subtracted from the total response to arrive at a reflected signal. The real slope reflects approximately 65% of the mode-1 internal tide as mode 1, less than two-dimensional linear calculations predict, because of the three-dimensional concavity of the topography. It is also less than recent glider estimates, likely as a result of along-slope inhomogeneity. The inhomogeneity of the response comes from the Tasman Rise that diffracts the incoming tidal beam into two beams: one focused along beam and one diffracted to the north. Along-slope inhomogeneity is enhanced by a partially trapped, superinertial slope wave that propagates along the continental slope, locally removing energy from the deep-water internal tide and reradiating it into the deep water farther north. This wave is present even in a simplified, straight slope topography; its character can be predicted from linear resonance theory, and it represents up to 30% of the local energy budget. [ABSTRACT FROM AUTHOR]

NPP’s power supply system is repairable and there is common cause failure between the components. The repair rate is introduced and total signaling is considered in the improved GO-FLOW method, aimed at reliability analysis for NPP’s power supply system. Traditional GO-FLOW operators’ algorithms are improved. Comprehensively considering the effect of total signaling flow in the power supply system, the equivalent reliability parameter model and common cause failure probability model of multimodal repairable components are constructed. The improved GO-FLOW model of NPP’s power supply system is set up. Based on the proposed model, components’ reliability parameters are computed. The failure probability time-varying trend in thirty years, respectively, of NPP’s offsite power source and power supply system, is simulated and analyzed. Compared with calculation results of dynamic fault tree analysis method, the validity and the simplicity of the improved GO-FLOW method are verified. The effectiveness and applicability of the improved GO-FLOW model for NPP’s power supply system are proved by simulation examples. [ABSTRACT FROM AUTHOR]

This paper proposes a two-stage fast convergence adaptive complex-valued independent component analysis based on second-order statistics of complex-valued source signals. The first stage constructs a cost function by extending the real-valued whiten cost function to a complex-valued domain and optimizes the cost function using a complex-valued gradient. The second stage uses the restriction that the pseudocovariance matrix of the separated signal is a diagonal matrix to construct the cost function and the geodesic method is used to optimize the cost function. Compared with other adaptive complex-valued independent component analysis, the proposed method shows a faster convergence rate and smaller error. Computer simulations were performed on synthesized signals and communications signals. The simulation results demonstrate the validity of the proposed algorithm. [ABSTRACT FROM AUTHOR]

Proportionate-type normalized subband adaptive filter (PNSAF-type) algorithms are very attractive choices for echo cancellation. To further obtain both fast convergence rate and low steady-state error, in this paper, a variable step size (VSS) version of the presented improved PNSAF (IPNSAF) algorithm is proposed by minimizing the square of the noise-free a posterior subband error signals. A noniterative shrinkage method is used to recover the noise-free a priori subband error signals from the noisy subband error signals. Significantly, the proposed VSS strategy can be applied to any other PNSAF-type algorithm, since it is independent of the proportionate principles. Simulation results in the context of acoustic echo cancellation have demonstrated the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

In many control system applications, tracking a periodic reference signal or rejecting a disturbance signal with a limited frequency band is a necessary task. Repetitive control systems are designed to perform such tasks. Because the repetitive control systems by nature have introduced unstable controller structures, control signal amplitude constraints commonly encountered in control system applications need to be considered with special care. Otherwise, the repetitive control system could become unstable when the control signals became saturated. Using the same framework of Model Predictive Control (MPC), but without the cost of online optimization that usually occurs in the MPC algorithms, this paper shows the design and implementation procedures of repetitive control of multi-input and multi-output systems with anti-windup mechanisms. Furthermore, by using Fourier analysis of a reference signal or a disturbance signal, the structure of a repetitive control system is determined. Simple and complex simulation examples are used to illustrate the procedures of design and implementation. [ABSTRACT FROM AUTHOR]

Purpose: X-ray dark-field imaging promises information on the small angle scattering properties even of large samples. However, the dark-field image is correlated with the object's attenuation and phase-shift if a polychromatic x-ray spectrum is used. A method to remove part of these correlations is proposed. Methods: The experimental setup for image acquisition was modeled in a wave-field simulation to quantify the dark-field signals originating solely from a material's attenuation and phase-shift. A calibration matrix was simulated for ICRU46 breast tissue. Using the simulated data, a dark-field image of a human mastectomy sample was corrected for the finger print of attenuation- and phase-image. Results: Comparing the simulated, attenuation-based dark-field values to a phantom measurement, a good agreement was found. Applying the proposed method to mammographic dark-field data, a reduction of the dark-field background and anatomical noise was achieved. The contrast between microcalcifications and their surrounding background was increased. Conclusions: The authors show that the influence of and dispersion can be quantified by simulation and, thus, measured image data can be corrected. The simulation allows to determine the corresponding dark-field artifacts for a wide range of setup parameters, like tube-voltage and filtration. The application of the proposed method to mammographic dark-field data shows an increase in contrast compared to the original image, which might simplify a further image-based diagnosis. [ABSTRACT FROM AUTHOR]

In this paper, an overhearing protocol is proposed for two-way cooperative multiantenna relaying systems, where the relays equipped with multiple antennas collaborate to relay signals between the base station (BS) and two user equipment units (UEs). In the proposed overhearing protocol, the UE in the uplink transmission phase transmits only in the first time slot, i.e., it remains silent in the second time slot, whereas the previous overhearing protocol assumes that the UE transmits also in the second time slot. Therefore, the proposed overhearing protocol is more power efficient. The precoding matrix at each cooperative relay is optimized in the sense of minimizing the weighted mean squared error (WMSE). Simulation results show that the proposed scheme shows not only lower mean squared error but also higher achievable sum rate than existing cooperative relaying schemes. [ABSTRACT FROM AUTHOR]

There is an emerging need to prioritize remedial frequency control measures closer to the source of an imbalance event. This approach, referred to herein as responsibilization, is challenging to achieve within the conventional operating times of Primary Frequency Control (PFC) and, therefore, novel methods are sought. In this letter, a novel decentralized PFC is proposed, which relies on transient phase offset to achieve fast responsibilization autonomously. The effectiveness of the proposed control is demonstrated by real-time simulations and its stability assessed by small-signal analysis. This development will lead to increased system resilience during imbalance events. [ABSTRACT FROM PUBLISHER]

The current study aimed to develop the mechanism for generating strain signal utilising computer-based simulation. The strain data, caused by the acceleration, were undertaken from a fatigue data acquisition involving car movements. Using a mathematical model, the measured strain signals yielded to acceleration data used to describe the bumpiness of road surfaces. The acceleration signals were considered as an external disturbance on generating strain signals. Based on this comparison, both the actual and simulated strain data have similar pattern. The results are expected to provide new knowledge to generate a strain signal via a simulation. [ABSTRACT FROM AUTHOR]

An experiment simulating coal seam under forced vibration conditions was conducted. Acceleration response and microseism signal during the experiment were collected and analyzed. It is found that, with an increasing amount of vibration, the natural frequency of the specimen decreases, and this phenomenon reflects fractures appearing in the specimen. Acceleration response signals show that peaks in shock excitation frequency and shock excitation acceleration affect the acceleration response, which reflects damage to the specimen. When shock excitation frequency nears natural frequency, the acceleration response first decreases and then increases. When resonance occurs, it reaches its maximum value. As shock excitation acceleration peaks increase, the acceleration response peak of the specimen also increases. We conclude that destruction is mainly concentrated in the coal seam evidenced by specimen destruction situation. Then shock excitation frequency and shock excitation acceleration influence on microseism signals were analyzed by Hilbert-Huang transform. By receiving these signals and analyzing their characteristics, it is beneficial to develop new methods to predict disasters underground dynamically in the future. [ABSTRACT FROM AUTHOR]

A sufficient condition for least mean squares (LMS) algorithm stability with a small set of assumptions is derived in this paper. The derivation is not, contrary to the majority of currently known conditions, based on the independence assumption or other statistic properties of the input signals. Moreover, it does not make use of the small-step-size assumption, neither does it assume the input signals are stationary. Instead, it uses a theory of discrete systems and properties of a discrete state-space matrix. Therefore, the result can be applied to a wide set of signals, including deterministic and nonstationary signals. The location of all eigenvalues of the matrix responsible for the LMS algorithm stability has been calculated. Simulation experiments, where the step size reaches a couple of hundreds without loss of stability, are shown to support the theory. On the other hand, simulation where the calculations based on the small-step-size theory provide a too large estimation of the upper bound for the step size, while the new condition gives a proper solution, is also presented. Therefore, the new condition may be used in cases where fast adaptation is necessary and when the independence theory or the small-step-size assumptions do not hold. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

We investigate a strategy to address the problem of low ship detection probability of space-based Automatic Identification System (AIS). A directional AIS antenna and an innovative beam scanning method are proposed, which scan the antenna across a wide swath to provide complete coverage and maintain the advantage of a narrow footprint to reduce signal collision. Aiming at the mission requirement of global ship detection by the year 2016, the appropriate swath, the scanning range and the scanning rate were studied and designed in detail. Theoretical analysis and simulations showed that this scanning antenna can greatly improve ship detection probability and hold the detection probability at an average reporting interval from six to 15 seconds for most oceans when compared with the traditional fixed wide beam antenna. Furthermore, the detection capacity of this scanning antenna was little affected by the heights of different Low Earth Orbits. The results of this work show that the design of the helical antenna along with the beam scanning method can be considered as a building block of future space-based AIS. [ABSTRACT FROM AUTHOR]

Abstract: The bin-normalized frequency-domain block LMS (FBLMS) algorithm has low computational burden and potential fast convergence; however, it suffers from a biased steady-state solution when the reference signal lags behind the desired signal or the adaptive filter is of insufficient length. This paper proposes a unified framework for the FBLMS algorithm, which can be used to comprehensively analyze its steady-state behavior. Furthermore, a modified FBLMS algorithm with guaranteed optimal steady-state performance is proposed based on the framework. Simulations are carried out to demonstrate the benefit of the proposed algorithm. [Copyright &y& Elsevier]

Abstract: In this paper the Generalized Seasonal Block Bootstrap (GSBB) method is applied to the first and the second order characteristics of the cyclostationary (CS) signal. The new method for detection of the significant frequencies in the Fourier expansions of the mean and the autocovariance functions of CS processes is provided. The consistency of GSBB is shown. Finally, the bootstrap pointwise and simultaneous confidence intervals are constructed and hence hypothesis tests for the presence of the first and the second order cyclostationarity can be performed. The real data example is presented to show the possible applications of our results. Moreover, the simulation study was performed to check the efficiency and robustness to the noise of the considered method. [Copyright &y& Elsevier]

ABSTRACT Small signal RF modeling of FinFETs is strongly dependent on the methodology used to extract transistor intrinsic and extrinsic parameters. In this article, an original extraction method is proposed for determining all FinFET extrinsic series elements values from S-parameters measurements at zero bias condition. The extracted technique is demonstrated through successful comparison between simulated and measured S-parameters over a widefrequency range. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:2616-2619, 2014 [ABSTRACT FROM AUTHOR]

ABSTRACT This article presents development and validation of an artificial neural network (ANN)-based model for accurate two-dimensional direction of arrival estimation of two coherent sources. The ANN model is developed using simulated signals and its performance is evaluated by measurements inside an anechoic chamber. Simulations and experiments show good agreement in estimating both azimuth and elevation angles of coherent sources. The proposed model demonstrates ability to separate two closely spaced sources and outperforms MUSIC with spatial smoothing preprocessing in the case of small number of signal snapshots. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:2558-2562, 2014 [ABSTRACT FROM AUTHOR]

DNA microarray technology has enabled biologists to study all the genes within an entire organism to obtain a global view of genes? interaction and regulation. This technology has a great potential in obtaining a deep understanding of the functional organization of cells. This paper is concerned with improving the processes involved in the analysis of microarray image data. The main focus is to clarify an image?s feature space in an unsupervised manner. Rather than using the raw microarray image, it proposes to produce filtered versions of the image data by applying nonlinear anisotropic diffusion so that the dynamic range of the image could be increased and, therefore, a better ability of signal extraction could be achieved. In this paper, a novel segmentation algorithm is developed. This algorithm is based on the Cellular Neural Network computational paradigm integrated with median and anisotropic diffusion filters. The AnaLogic CNN Simulation Toolbox for MATLAB (InstantVision Toolboxes for MATLAB) is used during the segmentation process. Quantitative comparisons among the proposed methods and GenePix® are carried out from both the objective and subjective points of view. It is shown that analogic algorithm integrated with Complex Diffusion filter is the best one to be applied to accomplish the segmentation. [ABSTRACT FROM AUTHOR]

In this paper, a novel algorithm is developed for identifying Hammerstein model. The static nonlinear function is characterized by function link artificial neural network (FLANN) and the linear dynamic subsystem by an ARMA model. The utilization of FLANN can not only result in a simple and effective representation of static nonlinearity but also simplify the learning algorithm. A two-step procedure is adopted to identify Hammerstein model by using a specially designed input signal, which separates the identification of linear part from that of nonlinear part. Levenberg-Marquart algorithm is used to learn the weights of FLANN. Simulation examples demonstrate the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

Wireless body area network (WBAN) collects significant signals of human body or environment information for health monitoring or professional services. But normal medium access protocols can hardly make a balance and ensure enough reliability of a network because there are specific features and service quality in WBAN applications. Contention access or fixed allocation of bandwidth cannot meet all nodes? requirements and may cause collisions and delay. Especially in emergency medical situations, some data must be transmitted immediately for accurate diagnosis and decision. The dropping of critical messages could possibly create life threatening results. In order to improve the reliability and efficiency of data transmission in WBAN, this paper proposes a fuzzy control medium access (FCMA) mechanism based on input parameters for performance gains. It controls the contention window in contention access period (CAP) and slots allocation in contention free period (CFP) according to nodes? status. Through simulation analysis, the improved performance of throughput, latency, and packets breakdown is demonstrated by efficient usage of bandwidth and avoidance of collision. [ABSTRACT FROM AUTHOR]

Analysis of the out-of-phase modulated photocurrent (MPC) signal, the so-calledYsignal, is proposed for determining the trapping–detrapping events, recombination processes and gap-state parameters in amorphous silicon. This is demonstrated by analysing experimentalYspectra obtained on this material from different laboratories including our own. Model simulations are also employed in which the amphoteric nature of the dangling bonds and their distribution according to the defect-pool model are taken into account. From the reconstruction of theYsignal, phase shift and MPC amplitude spectra, several contributions resolved from the frequency dependence of the experimentalYspectra are identified. Two electron trapping–detrapping processes are resolved. These are attributed to hydrogen-related positive defects and to transitions involving the D+/0level of the normal dangling bonds from the defect-pool distribution. At lower frequencies a residual contribution is resolved that is attributed to a term related to recombination through the D+/0and D0/−levels. Between 300 and 150 K the above recombination contribution is essentially from the D0/−and dominates theYsignal at lower frequencies. In this region a characteristic phase lead appears, which is attributed to the existence of safe hole traps in the valence band tail. Around 150 K, trapping–detrapping events in the conduction band tail dominate. [ABSTRACT FROM AUTHOR]

Highlights: [•] We model the optical process in liquid scintillator with Geant4 simulation toolkit. [•] We combine the optical process and the PMT response to simulate anode signal. [•] We performed experiments to benchmark the simulation results. [•] EJ301 and EJ339A are both good for PSD from simulation and experiment results. [•] EJ301 has a better PSD feature than EJ339A. [Copyright &y& Elsevier]

Highlights: [•] We investigate the joint influence of price and CO2 signals in DR programs. [•] We develop a simulation model consisting of a Markov-chain load model and a scheduling program. [•] Consumers’ attitude to the signals and willingness to change largely affect the load shift, bill saving and emission reduction. [•] The model could also provide suggestions on the required testing period to get sufficient load data. [ABSTRACT FROM AUTHOR]

SUMMARY In this paper, an adaptive fuzzy decentralized output feedback control approach is presented for a class of uncertain nonlinear pure-feedback large-scale systems with immeasurable states. Fuzzy logic systems are utilized to approximate the unknown nonlinear functions, and a fuzzy state observer is designed to estimate the immeasurable states. On the basis of the adaptive backstepping recursive design technique, an adaptive fuzzy decentralized output feedback is developed. It is proved that the proposed control approach can guarantee that all the signals of the resulting closed-loop system are semiglobally uniformly ultimately bounded (SUUB), and that the observer and tracking errors converge to a small neighborhood of the origin by appropriate choice of the design parameters. Simulation studies are included to illustrate the effectiveness of the proposed approach. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

In this paper, we present five different approaches to estimate direction of arrival (DOA) of multiple incident RF sources. The proposed methods are based on extracting the signal and noise subspaces from the Q matrix, R matrix, or both Q and R matrices of the QR decomposed received data matrix. The angle of the signal arrival is extracted from the signal subspace by using similar techniques as employed by MUSIC and ESPRIT methods. The simulation results are shown which verify accurate DOA estimates for both single and two sources. In addition, an experimental verification of the proposed methods is also presented. The methods are implemented in LabVIEW software and a prototype is built using National Instruments (NI) hardware. Furthermore, the details of experimental procedures are presented which includes interfacing the uniform linear array (ULA) of antennas with the NI-PXI platform, phase difference calibration between the RF receivers, and selection of transmitter and receiver parameters. The experimental results are shown for a single and two RF sources lying at arbitrary angles from the array reference, which verify the successful real-time implement-ability of the proposed DOA estimation methods. [ABSTRACT FROM AUTHOR]

This paper reflects a part of electromagnetic susceptibility studies conducted on active circuits. An electromagnetic interference (EMI) is injected on a 5 GHz monolithic voltage-controlled oscillator (VCO). This circuit is implemented on a 0.35 μm BiCMOS SiGe process. Injection locking and pulling are put in evidence when the circuit is subject to a high frequency interference with possible frequency band widened with respect to the oscillation frequency band of the VCO. A simulation process based on envelope-transient method is presented. Its main goal is to predict the behavior of the VCO under injection with interference signal power ranging from low to high level. [ABSTRACT FROM PUBLISHER]

Wireless multicast is a spectrum efficient method for group-data transmission. This paper focuses on energy efficient two-stage cooperative multicast transmissions, aiming to minimize the total transmission power while ensuring a practical coverage ratio. To focus on the relationship between the base station (BS) power at the first stage (PBS,C) and the total power consumption, a selective combining based on average received signal strength (SCA) is assumed at the receiver and the user density is supposed to be sufficiently high. Then a mobile relay (MR) arrangement based on sector ring structures is proposed for the second stage transmission, followed by an analytical derivation of the optimal PBS,C conditioned on a desired coverage ratio. In addition, further approximations are exploited to provide a simple theoretical estimation for the optimal PBS,C, whose effectiveness is verified by numerical results. It is shown that compared to the conventional one-stage multicast transmission, the proposed two-stage cooperative scheme can reduce the total power consumption and the BS power consumption by more than 40% and 80%, respectively. Although the proposed scheme is obtained based on SCA, when the user density is higher than 2 x 10-4, a coverage ratio of 95% can be guaranteed by using a practical CP combining with the proposed scheme. Moreover, the effectiveness of the proposed MR arrangement is verified by simulations where it outperforms other three arrangements. It is also shown that targeting at minimizing the total transmission power with guaranteed coverage, the proposed scheme significantly outperforms the existing two-stage scheme in terms of energy consumption and efficiency. [ABSTRACT FROM AUTHOR]

Networks on-chip (NoCs) provide enhanced performance, scalability, modularity, and design productivity as compared with previous communication architectures for VLSI systems on-chip (SoCs), such as buses and dedicated signal wires. Since the NoC design space is very large and high dimensional, evaluation methodologies rely heavily on analytical modeling and simulation. Unfortunately, there is no standardmodeling framework. In this paper we illustrate how to design and evaluateNoCs by integrating theDiscrete Event System Specification (DEVS)modeling framework and the simulation environment calledDEUS.Theadvantage of such an approach is that both DEVS and DEUS support modularity--the former being a sound and complete modeling framework and the latter being an open, general-purpose platform, characterized by a steep learning curve and the possibility to simulate any system at any level of detail. [ABSTRACT FROM AUTHOR]

Highlights: [•] The proposed system is a kind of Fabry–Perot interferometer (common optical path). [•] For the measuring range up to 100mm, only few dynamic FPI mentioned. [•] This optical structure is significantly reducing the effect of the tilt angle. [•] The derived equations and theoretical simulations have been completely described. [•] Modified signal mode can be much similar to sinusoidal signals. [ABSTRACT FROM AUTHOR]

Highlights: [•] A new fast compass alignment method based on repeated navigation solution is designed in detail. [•] In this method, alignment time is reduced without reducing alignment accuracy. [•] The reason why repeated navigation solution can be used for SINS compass alignment is given. [•] Two repeated navigation solution algorithms are compared, and forward–forward loop is chosen. [•] Simulation and test results indicate the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]