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This paper discusses the effect of losses in determining the optimal capacity of DC cable for a Solar Photovoltaic (PV) system application. The optimization problem is formulated to trade-off between the costs of losses against the cable investment cost over the operational lifetime of the cable. This is to minimize the total cost. The optimization problem is solved in closed form, clearly pointing...
The sampling rate offset (SRO) phenomenon in wireless acoustic sensor network (WASN) is considered in this work. The use of different clock sources in each node results in a drift between the nodes' signals. The aim of this work is to estimate these SROs and to re-synchronize the network, enabling coherent multi-microphone processing. First, the link between SRO and the Doppler effect is driven. Then,...
A PV arc-fault detection technique using spread spectrum time domain reflectometry (SSTDR) method has been introduced in this paper. SSTDR is a reflectometry method that has been commercially used for detecting aircraft wiring faults although SSTDR could be potentially used for many other applications. We have used SSTDR for detection of both ground and arc faults in a PV array. It has been demonstrated...
This paper presents a unique system specifically made to capture and create image mosaics of flat, wide, and shallow coral reefs at the Tubbataha Reefs Natural Park to assist in the rapid assessment of the reef scars caused by the grounding of the USS Guardian last January 17, 2013. This system is composed of an array of underwater cameras coupled with a GPS and depth logging device, and a mosaicking...
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...
Compact structure of the large-scale antenna array and low power angular spread (PAS) in vertical dimension improve the fading correlation of wireless channel dramatically in full-dimension multiple input multiple output (FD-MIMO) systems. Whereby beamforming (BF) can fully exploit the quasi-static spatial correlation to reduce dependence on the instantaneous channel state information at the transmitter...
Practical application of intracortical microelectrode technology is currently hindered by the inability to reliably record neuronal signals chronically. The precise mechanism of device failure is still under debate, but most likely includes some combination of tissue reaction, mechanical failure, and chronic material degradation. Impedance is a measure of the ease with which current flows through...
Climate modeling data are usually multidimen-sional arrays of floating-point numbers. These arrays typically have two or three spatial dimensions and one temporal dimension, describing the evolvement of climate variables in a time span. With the advances of high performance computing, the volume of climate data is expanding exponentially, bringing tough challenges for climate data archiving and sharing...
Design and Optimization of Sparse MMW synthesis aperture imaging array on hexagonal grids are researched in this paper. The arrangement of sparse array can be represented by configuration matrix. Using auto correlation matrix and cross correlation matrix of configuration matrix, distribution of sampling points in UV plane of hexagonal array is analyzed, and conditions for sampling points covering...
This paper proposes a novel demosaicing algorithm based on improved gradients with color correlation. Compared to conventional method, especially on region with dense lines and textures, the proposed method may reduce the probability on the edge direction judgment, which may lead to obvious artifacts. The improved adaptive gradients calculation uses color correlation information. The proposed method...
Clinical electrodes for epileptic seizure monitoring traditionally require a tradeoff between coverage area and spatial resolution. However, with multiplexed, flexible array devices, high spatial resolution is possible over large surface areas. This high resolution data, recorded from 360 electrodes or more, is difficult to review manually for subtle patterns. Here we develop innovative methods for...
This paper discusses the optimization procedure and the selection of the resolution of the analog/digital converter (ADC) for the Square Kilometre Array (SKA) receiver chain. Once the optimum input voltage levels of ADCs with different resolutions are selected, the maximum interference levels and correlator integration time are investigated for a two-antenna system. The selection methodology, based...
In this paper, we address the problem of estimating the two-dimensional (2-D) directions of arrival (DOA) of multiple signals, by means of a sparse L-shaped array. The array consists of one uniform linear array (ULA) and one sparse linear array (SLA). The shift-invariance property of the ULA is used to estimate the elevation angles with low computational burden. The source waveforms are then obtained...
In this paper a technique for estimating the single channel Wiener filter post-processor using two complementary adaptive near-field beamformers is presented as an alternative to voice activity detection for speech enhancement applications. Two near-field beamformers, the MVDR beamformer and an adaptive nullformer based on noise to signal maximisation, are used to generate estimates of signal and...
A robust sparse regularization technique for source localization that accounts for the joint effects of sensor position errors and noise is presented. Finding a good choice of the regularization parameter is a key component in sparse optimization problems and its automated determination is typically a non-trivial task. Our approach attempts to statistically determine an upper bound of the mean-squared...
A 2D antenna array introduces a new level of control and additional degrees of freedom in multiple-input-multiple-output (MIMO) systems particularly for the so-called “massive MIMO” systems. To accurately assess the performance gains of these large arrays, existing azimuth-only channel models have been extended to handle 3D channels by modeling both the elevation and azimuth dimensions. In this paper,...
Robust design is an effective approach to improve product quality and reduce manufacturing cost. Taguchi method, which is widely used, is a traditional method of robust design, but it can't solve the multi-response problem which often exists in engineering practice, even some responses are correlated. This paper uses principal component analysis (PCA) to eliminate the correlation among multiple responses...
An efficient approach for determination of incoming direction of electromagnetic (EM) signals radiated from multiple stochastic sources in far-field is presented in this paper. The approach is based on using a neural model realized by the Multi-Layer Perceptron (MLP) artificial neural network. MLP neural model, successfully trained by using correlation matrix of signals sampled by receiving antenna...
Passive geolocation of a skywave HF source requires accurate estimation of azimuth and elevation angles together with correct ionospheric modeling. Arrays of polarimetric vector sensors have been proposed to reduce the array aperture required for this purpose. However, several factors complicate their application including magneto-ionic raymode splitting resulting in closely-spaced arrivals in both...
A cross-shelf moored array, shipboard current profiler observations and glider observations were collected over the first few months of 2012 as part of a study of wintertime phytoplankton blooms off the coast of northern South Carolina, United States. The combined dataset is examined to document the internal wave field in the region inshore of the offshore deflection of the Gulf Stream. Moderate amplitude...
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