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Traditionally, the using an analog-to-digital conversion demands agreeing with the requirements of Shannon, Nyquist and Kotel'nikov theorem. According to this theorem, the frequency of the conversion should, at least, twice exceed the upper boundary frequency of the spectrum of the converted signal. It is also traditionally considered that the presence of high-frequency noises of more than one quantization...
In this paper, a new cyber-attack is proposed for distributed systems, while detection of such an attack is recommended based on H-infinity filtering. In particular, we study the effect of a specific attack on the communication links between local control centers. Today's cyber-physical systems are complex and large scale, so that they are distributed over a large area. Using distributed control and...
The Wiener filtering deconvolution algorithm applied to the correlation identification method which stability is poor and identification effect is undesirable that caused by the noise change of outside the band. The reasons of Wiener filtering deconvolution algorithm which adaptive of noise is unsatisfactory is analyzed by this undesirable consequence. The incremental wiener filter that used in correlation...
In this paper, an improved nonlinear resolution enhancement scheme based on Laplacian pyramid is proposed, which incorporates the peak sharpening technique into conventional nonlinear resolution enhancement methods. In the proposed scheme, the peak sharpening algorithms are firstly introduced to narrow the component with the shape preserved. Then the higher frequency component is generated by a nonlinear...
This paper proposes a photovoltaic (PV) power generation system, which is implemented by means of multilevel converters. The PV system is connected to utility grid and operates as a unified power quality conditioner (UPQC). Thus, the PV-UPQC system injects active power into the there-phase grid and, simultaneously, performs active power-line filtering, in order to improve the power quality. By using...
The paper briefly elaborates the basic principle and method of wavelet and wavelet packet analysis, and on this basic introduces the general method steps of making a denoising for signal by using of wavelet packet method. The designed computer simulation is made, and for an EEG test signal including random noising, the effects of wavelet and wavelet packet de-noising are compared by waveform and specific...
Orthogonal frequency division multiple access (OFDMA) has been widely used for multiple access in broadband wireless network. However, a major drawback of OFDMA signals is the high peak-to-average power ratio (PAPR). Tone reservation (TR) is a well known method using reserved subcarriers to design a peak-cancelling signal for lower PAPR of transmit OFDMA signals. In this paper, we propose an improved...
Image quality enhancement is a crucial requirement in many applications of digital image and video processing. Removing artifacts which are suffered from image compression will lose simultaneously image texture components. This paper combines Beltrami method and the window derivative to construct the texture map in an attempt to preserve image details during filtering artifacts. Texture map enhancement...
In the collaborative filtering recommendation technology, the similarity measurement part plays a vital role, and similarity measurement accuracy seriously affects the similarity measurement part and all the subsequent parts. However, there are many shortcomings in the similarity measurement part of traditional memory-based collaborative filtering recommendation technology. In order to solve the inaccuracy...
In this paper a time-domain iterative filtering technique is investigated to remove the need for iterative process and obtain a cross-correlation response close to an ideal thumbtack peak response with minimal sidelobes. Simulation results are reported for Gaussian random noise cases as well as for a case utilizing Barker code of length 13.
Distributed Denial of Service (DDoS) attacks have become a major threat to current networks. This article provides an overview on existing DDoS attacks generating tools and defense methods against them. The main difficulty of exploring DDoS attack features using such tools is the problem of raising huge real network and making lots of preparations to run tests executing these tools. We provide novel...
This paper presents the development of a new numerical algorithm for statistical inference problems that require sampling from distributions which are intractable. We propose to develop our sampling algorithm based on a class of Monte Carlo methods, Approximate Bayesian Computation (ABC), which are specifically designed to deal with this type of likelihood-free inference. ABC has become a fundamental...
This paper presents a novel multi-frame denoising method for low light images to get a clear shot even under dark conditions. To this end, multiple short-exposure images are aligned and filtered with a temporal-spatial filter to suppress the noise. Simulation results on real low-light scenes show that the proposed method outperforms the state-of-the-art image denoising method both on processing speed...
In this paper, a new nonlinear acoustic echo cancellation system is proposed, which utilizes adaptive 3rd-order Volterra filtering with a modified variable step-size GSPAP (VSS-GSPAP) algorithm. In particular, the proposed approach yields better echo cancellation performance than conventional VSS-NLMS methods in case of the double-talk situation in background noise. Simulation results demonstrate...
Botnets are one of the most serious threats to Internet security. Isolated and single point security defense technologies can't effectively counteract large-scale, distributed botnet attacks, such as Spamming and Distributed Denial of service attack. Collaboration among different kind of security devices is needed. To solve this problem, we proposed a conceptual model of botnet collaborative defense...
Clipping and filtering can be used to effectively reduce the peak-to-average power ratio (PAPR) of orthogonal frequency division multiplexing (OFDM) signals at the cost of introducing distortion. So far, various clipping and filtering techniques have been proposed in the literature, which have different performance in terms of PAPR reduction and signal distortion. However, the minimum signal distortion...
One of the major concerns of Orthogonal Frequency Division Multiplexing (OFDM) systems are its high Peak to Average Power Ratio (PAPR) values. These high PAPR values result in serious degradation in performance when a non-linear power amplifier is employed. The Conventional Partial Transmit Sequence (C-PTS) technique is one of the highly efficient methods for PAPR reduction in OFDM systems. Unfortunately,...
In present paper an innovating LED power supply based on inductive ballast is presented. New design cost efficient power supply is proposed as an alternative to high-end switch power supply (SMPS) for LED cluster feeding. The design schematics had been showed and circuit topology was explained. Ballast inductance and DC filtering capacitor sizing had been chosen after comparative studies of the output...
MANETS are used in a variety of applications today ranging from military communications networks to emergency response team networks. Their dynamic network topology is one of the greatest strength in employing MANETS, but invites many opportunities for cyber security attacks as computational power for these systems is always a viable resource. This paper documents a study where a MATLAB simulation...
This paper presents the development of the SNCF's HIL plateform whose purpose is testing, evaluation and validation of Energy Management Systems (EMS) for hybrid railway systems. In this way, The real EMS of the SNCF's hybrid locomotive PLATHEE has been coupled with modeling of the hybrid traction chain through a real Controller Area Network protocol (CAB) and signal HIL simulation has been performed‥...
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