Current Issue : July - September Volume : 2015 Issue Number : 3 Articles : 5 Articles
Digital multiple notch filters are used in a variety of applications to remove or suppress multiple sinusoidal or\nnarrow-band interference in digital signals. In this paper, we propose an all-pass filter-based design framework for\ninfinite impulse response (IIR) multiple notch filters. Our approach aims to overcome the limitations of former\ntechniques through greater design capacity and performance. The proposed framework has versatility and enables\nthe tailored use of design constraints thus providing a family of possible multiple notch filter design methods. The\ndesign performance and practicality of the proposed framework are verified empirically by a series of experimental\nresults and different applications....
This paper analyzes the characteristics of narrowband power line communication (NB-PLC) channels and assesses\ntheir performance when used for advanced metering infrastructure (AMI) communications. This medium has been\ntraditionally considered too hostile. However, the research activities carried out in the last decade have shown that it\nis a suitable technology for a large number of applications. This work provides a statistical characterization of NB-PLC\nchannels in the CENELEC-A band. The presented results have been obtained from a set of 106 links measured in\nurban, suburban, and rural scenarios. The study covers the input impedance of the power line network, the channel\nresponse and the noise. The analysis of the channel response examines the delay spread, the coherence bandwidth,\nand the attenuation, while the assessment of the noise considers both its spectral and temporal characteristics. Since\nlow voltage (LV) distribution networks consists of several conductors, they can be simultaneously used to set up\nmultiple-input multiple-output (MIMO) communication links. This paper investigates the correlation between the\nMIMO streams. The bit rates that can be attained both in the single-input single-output (SISO) and in the MIMO cases\nare estimated and discussed....
In this paper, we propose a bit-depth scalable lossless coding method for high dynamic range (HDR) images based on\na reversible logarithmic mapping. HDR images are generally expressed as floating-point data, such as in the OpenEXR\nor RGBE formats. Our bit-depth scalable coding approach outputs base layer data and enhancement layer data. It can\nreconstruct the low dynamic range (LDR) image from the base layer data and reconstructs the HDR image by adding\nthe enhancement layer data. Most previous two-layer methods have focused on the lossy coding of HDR images.\nUnfortunately, the extension of previous lossy methods to lossless coding does not significantly compress the\nenhancement layer data. This is because the bit depth becomes very large, especially for HDR images in floating-point\ndata format. To tackle this problem, we apply a reversible logarithmic mapping to the input HDR data. Moreover, we\nintroduce a format conversion to avoid any degradation in the quality of the reconstructed LDR image. The proposed\nmethod is effective for both OpenEXR and RGBE formats. Through a series of experiments, we confirm that the\nproposed method decreases the volume of compressed data while maintaining the visual quality of the\nreconstructed LDR images....
With the onset of large numbers of energy-flexible appliances, in particular plug-in electric and hybrid-electric\nvehicles, a significant portion of electricity demand will be somewhat flexible and accordingly may be responsive to\nchanges in electricity prices. In the future, this increased degree of demand flexibility (and the onset of only short-term\npredictable intermittent renewable supply) will considerably exceed present level of uncertainty in day-ahead\nprediction of assumed inelastic demand. For such a responsive demand idealized, we consider a deregulated\nwholesale day-ahead electricity marketplace wherein bids by generators (or energy traders) are determined through a\nNash equilibrium via a common clearing price (i.e., no location marginality). This model assumes the independent\nsystem operator (ISO) helps the generators to understand how to change their bids to improve their net revenue\nbased on a model of demand-response. The model of demand-response (equivalently, demand-side bidding day\nahead) is based on information from load-serving entities regarding their price-flexible demand. We numerically\nexplore how collusion between generators and loads can manipulate this market. The objective is to learn how to\ndeter such collusion, e.g., how to set penalties for significant differences between stated and actual demand, resulting\nin higher energy prices that benefit certain generators....
Aiming to reduce the power/mass requirements in satellite transponders and to reduce mission costs, joint\namplification of multiple carriers using a single high-power amplifier (HPA) is being considered. In this scenario, a\ncareful investigation of the resulting power efficiency is essential as amplification is nonlinear, and multicarrier signals\nexhibit enlarged peak-to-average power ratio. Thus, operating the amplifier close to saturation vastly increases signal\ndistortion resulting in a severe degradation of performance, especially for higher order modulations. This paper\nproposes a reduced-complexity digital predistortion (DPD) scheme at the transmitter and a corresponding equalizer\n(EQ) at the receiver to mitigate these nonlinear effects. Scenarios include both the forward as well as the return links.\nIn particular, the paper exploits the MIMO Volterra representation and builds on a basis pursuit approach using a\nLASSO (least absolute shrinkage and selection operator) algorithm to achieve an efficient basis representation,\navoiding large computational complexity, to describe the selection of predistorter/equalizer model. The work further\ncompares and contrasts the two mitigation techniques taking various system aspects into consideration. The gains in\nperformance and amplification efficiency demonstrated by the use of DPD/ EQ motivate their inclusion in\nnext-generation satellite systems....
Loading....