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In Disruption Tolerant Network(DTN), determining the exact location of data and amount of delay to query the data by a requester is a major concern. It is costly for a node to maintain information of opportunistic paths to every other node in a DTN. Identifying appropriate caching locations is a difficult task. In this paper, we propose a technique for selecting the nodes for caching data based on...
Consider the problem of source number detection in the presence of nonuniform noise, a new method based on the orthogonality of noise subspace and signal subspace is proposed. Estimate the direction of any incident signal, get eigen-decomposition of the covariance matrix and calculate the inner product vector of eigenvector and the steering array vector. Then a sequential hypothesis test is proposed...
Based on joint iterative optimization, a robust widely linear (WL) reduced-rank minimum variance distortion less response (MVDR) beam forming algorithm is proposed for noncircular signals. To handle the issue of the mismatch between the presumed array steering vector and actual array steering vector, a diagonal loading technique is devised. As the proposed beam former takes advantage of the noncircular...
This paper addresses the problem of passive wideband localization of a shallow water noise source in near-field with a horizontal array in the presence of multipath propagation. Multipath propagation gives rise to attenuated and time-delayed replicas of the original transmitted signal. The conventional beamforming approach to wideband localization involves the coherent signal-subspace method (CSM)...
Tools and methods able to simplify the development process of parallel software, but also to assure a high level of performance and robustness, are necessary. Power lists and their variants are data structures that can be successfully used in a simple, provably correct, functional description of parallel programs, which are divide-and-conquer in nature. The paper presents how programs defined based...
In this paper, the asymptotic favorable propagation (FP) condition is thoroughly analyzed under the assumption that user terminals (UTs) are gathered in a size-limited circular area. Uniform distribution is assumed for UTs. Assumptions that are accordant with realistic propagation environment are used, which mathematically bring in close-form approximations for mean and variance of FP. Based on these...
In this work, we argue that energy management should be a guiding principle for design and implementation of algorithms. Traditional complexity models for algorithms are simple and do not aid in design of energy-efficient algorithms. In this work, we conducted a large number of experiments to understand energy consumption for algorithms. We study the energy consumption for popular vector operations,...
Adaptive equalization is a widely used method of mitigating the effects of multipath propagation and Doppler spreading in underwater acoustic communication channels. This paper examines some specifics associated with the design of a multi-channel equalizer for time-varying underwater acoustic channels. More specifically, we study how the number of sensors and separation between them impact the equalization...
Falling is a common health problem for elderly. To address the problem, we are currently developing an acoustic fall detection system, FADE, which automatically detects a fall and reports to the caregiver. Of great importance of the fall detection system is a low false alarm rate that can be achieved by knowing where the acoustic signal comes from. The previous work showed the sound source localization...
A hearing aid, worn in or around a wearer's ear, is an electroacoustic device to block noise and enhance target sound signal for the wearer. However, there is no method in traditional hearing aids that can automatically separate noise from a received signal mixture. Especially when the backing round is complex, amplified sound by a traditional hearing aid is still a multi-source mixture, and its wearer...
Recently, the direction-of-arrival (DOA) estimation using an array antenna has been studied extensively. Accordingly, array calibration method has also become an important topic. Conventional data acquisition methods often require a positioner or an azimuth table to make sources of known DOAs for pre-measurement of array calibration in a radio anechoic chamber. However, such a measurement is both...
MIMO radar and Khatri-Rao (KR) product virtual array are the methods for increasing angular resolution of the array radar. The KR product is not suited to radar because KR product needs data property of uncorrelated wave incidence. However, when we extract responses of moving targets having different Doppler frequencies by Doppler filtering, the KR product array works almost properly because their...
Efficient calculation of the greatest common divisor (GCD) for big integers each whose number of bits is greater than or equal to 1024 has drawn a considerable amount of attention because it can be used to detect a weakness of the RSA security infrastructure. This paper presents a parallel binary GCD algorithm and its implementation for big integers on the Intel Xeon Phi coprocessor. This algorithm...
This paper presents the control of a Photovoltaic (PV) using a fuzzy model approach. A fuzzy controller will be designed based on a Takagi-Sugeno (TS) fuzzy plant model of the PV. This proposed controller is capable of driving the system states of the PV to follow those of a stable reference fuzzy model with the stability of the closed-loop system guaranteed‥ The simulation results through Matlab/Simulink...
A novel algorithm has been proposed for joint angle and frequency estimation based on uniform rectangular acoustic vector sensors array. The joint angle and frequency problem is linked to a parafac quadrilinear model. Exploiting this link, it drives a quadrilinaear decomposition-based joint angle and frequency algorithm. This proposed algorithm has improved angle and frequency estimation compared...
In this paper, a calibration method is proposed for a nonplanar array with arbitrary geometry. This method can estimate the errors of array sensor position, gain and phase simultaneously using known calibration sources. Note that the technique does not use iterative calculation in estimating the array parameters and hence it has no convergent problem. However, it requires that four directions of arrival...
Mutual coupling is a practical problem in array signal processing, which seriously degrades the performance of most high-resolution array processing methods. In this paper, an improved sparse representation method is proposed for direction-of-arrival estimation in the presence of unknown mutual coupling. By making use of the special structure of mutual coupling matrix for uniform linear array, the...
In this paper we address a novel method of eliminating ambiguity for planar array. It is known that ambiguity appears in the direction of arrivals (DOA) estimation when the aperture of the array is large enough. We propose a method of rotating the array to solve the ambiguity problem. Firstly, we use multiple signal classical algorithm (MUSIC) to estimate DOA. Then we rotate an angle of the array...
Content-based image retrieval system needs a feature vector with dimensionality as lower as possible. In this paper, we propose an image retrieval system using low-dimensional color feature vector containing only one image feature termed as weighted average of colorful image. For finding similar images, the euclidean distance between the feature vector of query image and each feature vector of database...
The health state evaluation method is one of the key technologies of Prognostic and Health Management (PHM). Through the health assessment of the satellite power system, it can timely find the potential trend of health degradation and hidden danger of influence of health level, thus improving the level of effectiveness, precision and autonomation of the power system management. Firstly, it analyzed...
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