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This paper addresses the problem of acquiring weak high-order binary offset carrier (BOC) signals in the context of high-sensitivity global navigation satellite system (HS-GNSS) receivers. The use of high-order BOC modulations provides an improvement over conventional BPSK modulation in terms of positioning accuracy, at the cost of secondary peaks appearing in the correlation function. The acquisition...
This paper presents the features of the MONITOR project. This project initiated by ESA / ESTEC aims to increase the knowledge of the ionospheric effects and its impact on GNSS systems during active periods of solar activity. It includes the deployment of a set of GNSS-based ionospheric monitoring receivers worldwide distributed, the development of specific analysis software tools some of them integrated...
The selection of the right low-power coding technique during the design of the interconnect architecture has a high potential. However, it requires the analysis and evaluation to be performed at high-levels of abstraction. Closed formulas to quantify the power reduction achieved by each low-power code are therefore highly desirable. Using a simplified Dual Bit Type model for the underlying signals,...
Heart Rate Turbulence (HRT) is a powerful risk stratification criterion in patients with cardiac disorders. Several physiological factors affect HRT, e.g., previous cardiac cycle (CC), coupling interval (CI), and compensatory pause (CP). However, classical HRT measurements often use an average of the available individual tachograms that might blur relevant physiological relationships. We hypothesized...
Although a number of studies have addressed the clinical usefulness of Heart Rate Variability (HRV) as a marker of the autonomic activity, there are few studies about the short-term day-to-day reproducibility of HRV nonlinear indices. A database of 31 7-Day Holters (7DH) from Chronic Heart Failure patients was used to analyze the reliability of nonlinear dynamics and to evaluate the usefulness of...
ECG, measuring body-surface electrical waves generated in the heart, is the golden standard for diagnosis of various cardiovascular diseases. The 2011 Physionet challenge visions mobile phones that can be used to collect and analyse ECG records. Such devices are particularly useful in underdeveloped regions, which have a large population size but lack adequate primary care capacity. Signals collected...
The increasing success of P2P-TV applications, that may overwhelm the network with their large volume of traffic in the near future, calls for the need of new traffic models that can effectively represent the traffic generated by these applications. In this paper, we study the traffic generated by PPLive and SopCast, that are among the most popular P2P-TV applications of today, and propose Hidden-Markov...
One of the current limitations to evaluate the impact of a realistic multipath environment over a GNSS receiver is the high number of multipath rays that are needed to model the channel in a HW RF constellation simulator. That makes necessary the application of reduction techniques to decrease the number of channels per satellite to be simulated. The initial evaluation of two reduction techniques...
A concern is any consideration that can impact the software architecture and other artefacts. Sustaining stability of concerns realised in architectural designs is essential to obtain long-lasting software products. It is often assumed that concern assessment mechanisms are effective to predict architecture stability. They ought to exert a positive or detrimental effect on software stability. In fact,...
Images taken with different focus settings are used in shape-from-focus to reconstruct the depth map of a scene. A problem when acquiring images with different focus settings is the shift of image features due to changes in magnification. This paper shows that those changes affect the shape-from-focus performance and that the final reconstruction can be improved by compensating for that shift. The...
MEMO systems where multipath fading is only partially correlated could use polarization diversity to provide a higher diversity gain. Recent letters have proposed the use of tri-polarized antennas and a novel true polarization diversity (TPD) scheme. In this paper, the full potential of TPD is evaluated with both simulations and measurements and compared to conventional orthogonal polarization diversity...
Fire severity can be considered one of the most influential factors in the postfire development of burnt areas. Ground level studies documenting changes in reflectance values improve the discrimination of spatial fire severity across large areas. The objective of this study was to determine those spectral regions most sensitive to fire severity levels by investigating the relationship between postfire...
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