Recently, a considerable growth of interest in projected gradient (PG) methods has been observed due to their high efficiency in solving large-scale convex minimization problems subject to linear constraints. Since th...
Recently, a considerable growth of interest in projected gradient (PG) methods has been observed due to their high efficiency in solving large-scale convex minimization problems subject to linear constraints. Since the minimization problems underlying nonnegative matrix factorization (NMF) of large matrices well matches this class of minimization problems, we investigate and test some recent PG methods in the context of their applicability to NMF. In particular, the paper focuses on the following modified methods: projected Landweber, Barzilai-Borwein gradient projection, projected sequential subspace optimization (PSESOP), interior-point Newton (IPN), and sequential coordinate-wise. The proposed and implemented NMF PG algorithms are compared with respect to their performance in terms of signal-to-interference ratio (SIR) and elapsed time, using a simple benchmark of mixed partially dependent nonnegative signals.
A new in time passive localization system based on multi base-line phase comparison receivers is proposed. The new system uses short base-line to avoid the long base-line phase illegibility then uses the phase differe...
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Based on the property of Human vision system (HVS) that human eye's sensitivity to an image varies with different information regions of the image, Pulse-coupled neural network (PCNN) model is modified for image s...
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Based on the property of Human vision system (HVS) that human eye's sensitivity to an image varies with different information regions of the image, Pulse-coupled neural network (PCNN) model is modified for image segmentation. The modified PCNN stimulated by an input image has pulse output with multiple pulse values rather than only two in the conventional PCNN, according to the local information rate of the input image. This results in image segmentation according to local information rate delivered from the image by the modified PCNN. Experiments with the modified PCNN on image segmentation and image compression on the segmented images with the principle that the lower information rate is, the higher compression rate is applied, show much better performance in compression rate compared with that on the segmented images with the conventional PCNN.
For Multi-Carrier-Code Division Multiple Access (MC-CDMA) systems, it is usually assumed that the fading of the subcarriers is frequency non-selective and independent of each other. This paper shows that the two ass...
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For Multi-Carrier-Code Division Multiple Access (MC-CDMA) systems, it is usually assumed that the fading of the subcarriers is frequency non-selective and independent of each other. This paper shows that the two assumptions are incompatible. In fact, the MC-CDMA signals at each subcarrier undergo fading that are highly correlated. Based on this observation, this paper develops a simulation algorithm for Rayleigh fading channels via frequency-domain correlation functionl which incorporates the Doppler effect simultaneously. Numerical examples are presented to demonstrate the effectiveness of the new algorithm, with the conclusion that the independence assumption of subcarrier fading overrates the system performance.
In order to periodically reassess the status of the alternate path route(APR)set and to improve the efficiency of alternate path construction existing in most current alter-nate path routing protocols,we present a cro...
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In order to periodically reassess the status of the alternate path route(APR)set and to improve the efficiency of alternate path construction existing in most current alter-nate path routing protocols,we present a cross-layer design and ant-colony optimization based load-balancing routing protocol for ad-hoc networks(CALRA)in this *** CALRA,the APR set maintained in nodes is aged and reas-sessed by the inherent mechanism of pheromone evaporation of ant-colony optimization algorithm,and load balance of network is achieved by ant-colony optimization combining with cross-layer synthetic *** efficiency of APR set construction is improved by bidirectional and hop-by-hop routing update during routing discovery and routing maintenance ***,ants in CALRA deposit simulated pheromones as a function of multiple parameters corresponding to the information collected by each layer of each node visited,such as the distance from their source node,the congestion degree of the visited nodes,the current pheromones the nodes possess,the velocity of the nodes,and so on,and provide the information to the visiting nodes to update their pheromone tables by endowing the different parameters corresponding to different information and different weight values,which provides a new method to improve the congestion problem,the shortcut problem,the convergence rate and the heavy overheads commonly existed in existing ant-based routing protocols for ad-hoc *** performance of the algorithm is measured by the packet delivery rate,good-put ratio(routing overhead),and end-to-end *** results show that CALRA performs well in decreasing the route overheads,balancing traffic load,as well as increasing the packet delivery rate,etc.
A novel approach combining a time-frequency representation of brain activity in the form of recorded EEG signals together with nonnegative matrix factorization (NMF) post-processing section in brain computer interface...
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In this article, we propose a (t,n) threshold verifiable multi-secret sharing scheme, in which to reconstruct t secrets needs to solve t simultaneous equations. The analysis results show that our scheme is as easy as ...
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A method based on the fast adaptive chirplet transform is presented for bearing vibration signal analysis. Based on parameters coarse estimation, it converts multi-dimension optimization process to a traditional curve...
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The paper presents an effective algorithm to analyze MR-images in order to recognize Alzheimer's disease (AD) which appeared in patient's brain. The features of interest are categorized in features of the spat...
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The paper presents an effective algorithm to analyze MR-images in order to recognize Alzheimer's disease (AD) which appeared in patient's brain. The features of interest are categorized in features of the spatial domain (FSD's) and Features of the frequency domain (FFD's) which are based on the first four statistic moments of the wavelet transform. Extracted features have been classified by a multi-layer perceptron artificial neural network (ANN). Before ANN, the number of features is reduced from 44 to 12 to optimize and eliminate any correlation between them. The contribution of this paper is to demonstrate that by using the wavelet transform number of features needed for AD diagnosis has been reduced in comparison with the previous work. We achieved 79% and 100% accuracy among test set and training set respectively, including 93 MR-images.
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