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Investigation of nonlinear dynamical properties by the observed complex behaviour as a basis for construction of dynamical models of atmospheric photochemical systems

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FARADAY DISCUSSIONS 2001年第0期120卷 105-123页

作者： Feigin, AM Molkov, YI Mukhin, DN Loskutov, EM Russian Acad Sci Inst Appl Phys Nizhnii Novgorod 603950 Russia

The importance of the investigation of nonlinear dynamical properties (NDPs) of the atmospheric photochemical systems (PCSs) was demonstrated in ref. 1 and 2 (A. M. Feigin and I. B. Konovalov, J. Geophys. Res., 1996, 101 (D20),26038;1. B. Konovalov, A. M. Feigin and A. Y. Mukhina, J. Geophys. Res., 1999,104 (D3), 3669). The only known way to study NDPs of any natural dynamical system (including atmospheric PCSs) is to construct a mathematical model of the system. The key point here is adequacy of the NDPs of the constructed model to the system observed. We propose a new approach to construction of such an adequate model for systems manifesting nonstationary chaotic behaviour and describe an algorithm based exclusively on nonlinear dynamical analysis of the observed time series (TS) without invoking any a priori knowledge about the properties of the system observed. Potentialities of the algorithm are demonstrated with the aid of a computer model of the mesospheric PCS. The duration of the "observed" TS is limited so that the system demonstrates only one-chaotic-type of behaviour, without any bifurcations throughout the observed TS. The proposed algorithm enabled us to make a correct prognosis of bifurcation sequences and calculate probabilities to reveal, at the time instant of interest, predicted regimes of the system's behaviour for times much greater than the length of the initial TS.

关键词： .calculate exclusively proposed algorithm time instant bifurcations Geophys Res nonlinear dynamical dynamical models atmospheric photochemical NDPs atmospheric PCSs nonstationary chaotic observed time mesospheric observed TS predicted regimes system behaviour

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Wave Height Field Measurement Using a Compact Dual-frequency HF Radar

Wave Height Field Measurement Using a Compact Dual-frequency...

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OCEANS - MTS/IEEE Kobe Techno-Oceans Conference (OTO)

作者： Tian, Yingwei Wen, Biyang Tian, Zhen Wuhan Univ Sch Elect Informat Wuhan 430072 Hubei Peoples R China

ISBN: (纸本)9781538616543

Compact high frequency (HF) radar using small antenna has been widely accepted in ocean surface current mapping, but is challenging in measurement of wave height, particularly wave height field, due to its broad beam. First-order Bragg scattering theory has been explored to estimate sea state, including wind speed and wave height, from the first-order ocean echo, which provides a capability of distinguishing waves information over different directions. However, this method is troubled by the calibration of direction dependent spreading factor. A new approach is proposed by adopting a dual-frequency compact radar, and the ratio of power of Bragg resonant waves associated with two frequencies, rather than that of a single frequency, is utilized to simultaneously eliminate the effect of spreading factor and estimate wave height. In addition, direction finding algorithm such as multiple signal classification (MUSIC) is employed to obtain wave field information. Preliminary results are presented to verify the effectiveness of the proposed algorithm.

关键词： HF MUSIC proposed algorithm Multiple signal classification Wave Height Hf(hafnium) High frequency High frequency radar sea states Dual band single-frequency hyaluronate lyase Compact Compact Pattern

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Parameter estimation in a spiking-bursting H-R neural model with random fluctuation

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DIFFERENTIAL EQUATIONS AND DYNAMICAL SYSTEMS 2021年第4期29卷 857-869页

作者： Mondal, Argha Paul, Chinmoy Vishwakarma, Gajendra Kumar Upadhyay, Ranjit Kumar Indian Sch Mines Dept Appl Math Indian Inst Technol Dhanbad 826004 Bihar India

This article reports a method for the estimation of parameters of a 3D Hindmarsh Rose neural model under a noisy measurement. Estimation procedure is based on reparametrization of the 3D model in a linear form. Method of least square has been used to estimate the biophysical parameters of the model. It is known that the presence of unavoidable noise effects the estimation procedure. To reduce the influence of noise to a certain extent, a denoising algorithm based on local projection is considered. Estimation procedure has been derived both in noisy and denoised condition to present the effectiveness of the algorithm. The denoising technique has been applied to reduce the influence of noisy stimuli in an experimentally collected EEG data set and the results are presented in terms of reduction in variance level. The effectiveness of the method is presented using analytical/mathematical and simulation results.

关键词： H-R neural model Estimation proposed algorithm Denoising

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Fast Subspace Tracking algorithm Based on the Constrained Projection Approximation

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EURASIP JOURNAL ON ADVANCES IN SIGNAL PROCESSING 2009年第unknown期2009卷 576972-576972页

作者： Valizadeh, Amir Karimi, Mahmood Shiraz Univ Dept Elect Engn Shiraz *** Iran Engn Res Ctr Tehran *** Iran

We present a new algorithm for tracking the signal subspace recursively. It is based on an interpretation of the signal subspace as the solution of a constrained minimization task. This algorithm, referred to as the constrained projection approximation subspace tracking (CPAST) algorithm, guarantees the orthonormality of the estimated signal subspace basis at each iteration. Thus, the proposed algorithm avoids orthonormalization process after each update for postprocessing algorithms which need an orthonormal basis for the signal subspace. To reduce the computational complexity, the fast CPAST algorithm is introduced which has O(nr) complexity. In addition, for tracking the signal sources with abrupt change in their parameters, an alternative implementation of the algorithm with truncated window is proposed. Furthermore, a signal subspace rank estimator is employed to track the number of sources. Various simulation results show good performance of the proposed algorithms. Copyright (C) 2009 A. Valizadeh and M. Karimi.

关键词： .Approximation proposed algorithm Fast Subspace Tracking tracking the signal

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Detection and localization of image tampering in digital images with fused features

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CONCURRENCY AND COMPUTATION-PRACTICE & EXPERIENCE 2022年第23期34卷 e7191-e7191页

作者： Ahmad, Mohassin Khursheed, Farida Natl Inst Technol Elect & Commun Srinagar 190006 Jammu & Kashmir India Natl Inst Technol Srinagar Jammu & Kashmir India

In digital forensics, image tamper detection and localization have attracted increased attention in recent days, where the standard methods have limited description ability and high computational costs. As a result, this research introduces a novel picture tamper detection and localization model. Feature extraction, tamper detection, as well as tamper localization are the three major phases of the proposed model. From the input digital images, a group of features like "Scale-based Adaptive Speeded Up Robust Features (SA-SURF), Discrete Wavelet Transform (DWT) based Patched Local Vector Pattern (LVP) features, HoG feature with harmonic mean based PCA and MBFDF" are extracted. Then, with this extracted feature strain the "optimized Convolutional Neural Network (CNN)" will be trained in the tamper detection phase. Since it is the key decision-maker about the presence/absence of tamper, its weighting parameters are fine-tuned via a novel improved Sea-lion Customized Firefly algorithm (ISCFF) model. This ensures the enhancement of detection accuracy. Once an image is recognized to have tampers, then it is essential to identify the tamper localization. In the tamper localization phase, the copy-move tampers are localized using the SIFT features, splicing tampers are localized using the DBN and the noise inconsistency is localized with a newly introduced threshold-based tamper localization technique. The simulation outcomes illustrate that the adopted model attains better tamper detection as well as localization performance over the existing methods.

关键词： digital images optimized convolutional neural network (CNN) proposed algorithm tamper detection and localization

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The derivation of a new blind equalization algorithm

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ETRI JOURNAL 1996年第2期18卷 53-60页

作者： Kim, Y Kim, S Kim, M Mobile Multimedia Section Mobile Communications Department ETRI ETRI Mobile Multimedia Section Mobile Communications Department of the Electronics and Telecommunications Research Institute(ETRI

Blind equalization is a technique for adaptive equalization of a communication channel without the aid of training sequences. This paper proposes a new blind equalization algorithm. The advantage of the new algorithm is that it has the lower residual error than the GA (proposed by Godard) and Sign-GA (proposed by Weerackody et al.). The superior performance of the proposed algorithm is illustrated for the 16-QAM signal constellation. A Rummler channel model is assumed as a transmission medium. The performance of the proposed algorithm is compared to the GA, Sign-GA and Stop & Go algorithm (SGA). The simulation results demonstrate that an improvement in performance is achieved with the proposed equalization algorithm.

关键词： .New algorithm Equalizer QAM SGA proposed algorithm Mobile Multimedia New Blind Equalization residual error Rummler

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Resource Allocation with MAC Layer Node Cooperation in Cognitive Radio Networks

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INTERNATIONAL JOURNAL OF DIGITAL MULTIMEDIA BROADCASTING 2010年第unknown期2010卷

作者： Merentitis, Andreas Triantafyllopoulou, Dionysia Univ Athens Dept Informat & Telecommun Athens 15784 Greece

An algorithm for cooperative Dynamic Spectrum Access in Cognitive Radio networks is presented. The proposed algorithm utilizes Medium Access Control layer mechanisms for message exchange between secondary nodes that operate in license exempt spectrum bands, in order to achieve interference mitigation. A fuzzy logic reasoner is utilized in order to take into account the effect of the coexistence of a large number of users in the interference as well as to cope for uncertainties in the message exchange, caused by the nodes' mobility and the large delays in the updating of the necessary information. The proposed algorithm is applied in Filter Bank Multicarrier, as well as Orthogonal Frequency Division Multiplexing systems, and its performance is evaluated through extensive simulations that cover a wide range of typical scenarios. Experimental results indicate improved behaviour compared to previous schemes, especially in the case of uncertainties that cause underestimation of the interference levels.

关键词： .Mechanisms Delays Uncertainties proposed algorithm Cognitive Radio Reasoner Digital Multimedia Broadcasting spectrum bands

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Efficient computation of shortest paths in networks using particle swarm optimization and noising metaheuristics

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DISCRETE DYNAMICS IN NATURE AND SOCIETY 2007年第unknown期2007卷 1-25页

作者： Mohemmed, Ammar W. Sahoo, Nirod Chandra Multimedia Univ Fac Engn & Technol Jalan Ayer Keroh Lama 75450 Melaka Malaysia

This paper presents a novel hybrid algorithm based on particle swarm optimization (PSO) and noising metaheuristics for solving the single-source shortest-path problem (SPP) commonly encountered in graph theory. This hybrid search process combines PSO for iteratively finding a population of better solutions and noising method for diversifying the search scheme to solve this problem. A new encoding/decoding scheme based on heuristics has been devised for representing the SPP parameters as a particle in PSO. Noising-method-based metaheuristics ( noisy local search) have been incorporated in order to enhance the overall search effciency. In particular, an iteration of the proposed hybrid algorithm consists of a standard PSO iteration and few trials of noising scheme applied to each better/improved particle for local search, where the neighborhood of each such particle is noisily explored with an elementary transformation of the particle so as to escape possible local minima and to diversify the search. Simulation results on several networks with random topologies are used to illustrate the effciency of the proposed hybrid algorithm for shortest-path computation. The proposed algorithm can be used as a platform for solving other NP-hard SPPs. Copyright (c) 2007 A. W. Mohemmed and N. C. Sahoo. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

关键词： .topologies proposed algorithm local search encoding/decoding SPP hybrid algorithm Particle Swarm elementary transformation shortest-path metaheuristics standard PSO hybrid search noising method proposed hybrid

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Joint Beamforming and Power Allocation Design in Downlink Non-Orthogonal Multiple Access Systems

Joint Beamforming and Power Allocation Design in Downlink No...

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IEEE Globecom Workshops

作者： Xiaofang Sun Chao Shen Yanqing Xu Suhaib M. Al-Basit Zhiguo Ding Nan Yang Zhangdui Zhong State Key Lab of Rail Traffic Control and Safety Beijing Jiaotong University School of Computing and Communications Lancaster University Research School of Engineering Australian National University

ISBN: (纸本)9781509024834

We propose a joint design of beamforming and power allocation in a downlink multiple-input multiple-output multiuser system which employs non-orthogonal multiple access (NOMA). We address a new scenario where the users are divided into two groups by their quality of service (QoS) requirements, rather than the location information, such that the users in Group 1 expect to be served with the best efforts whereas the users in Group 2 require to reach target rates. For this scenario, The aim is to maximize the sum rate of the users in Group 1 while guarantee the minimum rates of the users in Group 2. We first apply the semidefinite relaxation (SDR) approach to linearize the quadratic forms of beamforming vectors, and then successively approximate the nonconvex constraints based on the arithmeticgeometric mean inequality to jointly design the beamforming matrices and power allocation. Finally, we show that the proposed algorithm achieves a profound sum rate advantage over the existing ones, and examine the impact of parameters on the convergence rate of the proposed algorithm.

关键词： output multiuser system employs proposed algorithm

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SINGLE IMAGE BRIGHTENING VIA EXPOSURE FUSION

SINGLE IMAGE BRIGHTENING VIA EXPOSURE FUSION

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IEEE International Conference on Acoustics, Speech and Signal Processing

作者： Zhengguo Li Jinghong Zheng Signal Processing Department Institute for Infocomm Research 1 Fusionopolis Way Singapore

ISBN: (纸本)9781479999897

It is very challenging to capture images via cell phone cameras in low-lighting conditions due to possible motion blur, especially for a high dynamic range (HDR) scene. In this paper, a new single image brightening algorithm is introduced to support capturing an image with a small exposure time and a small ISO value for a low-lighting scene. There are negligible motion blur and over-exposed pixels in the captured image while both details in the darkest regions and the brightness of the image are reduced. The proposed algorithm is applied to brighten the under-exposed regions and to enhance details of the under-exposed regions with negligible increment on the brightness of the brightest areas. The proposed algorithm can also be adopted to brighten an image captured for an HDR scene at day time but with dark objects.

关键词： darkest regions proposed algorithm under-exposed regions images image brightness motion blur Imagery (Psychotherapy) Brightening brightness Fusion reactions Fusion, biological FUSION fusion (melting) exposure time Image GATA3 gene hot dry rocks

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