A novel low-power full-adder cell for low voltage

This paper presents a novel low-power majority function-based 1-bit full adder that uses MOS capacitors (MOSCAP) in its structure. It can work reliably at low supply voltage. In this design, the time-consuming XOR gates are eliminated. The circuits being studied are optimized for energy efficiency at 0.18-μm CMOS process technology. The adder cell is compared with seven widely used adders based on power consumption, speed, power-delay product (PDP) and area efficiency. Intensive simulation runs on a Cadence environment and HSPICE show that the new adder has more than 11% in power savings over a conventional 28-transistor CMOS adder. In addition, it consumes 30% less power than transmission function adder (TFA) and is 1.11 times faster.     

A New Construction of Signature Waveforms for Multi-rate Multi-cell QS-CDMA Systems

In this paper, we propose a new construction of signature waveform sets based on Generalized Loosely Synchronization (GLS) sets and different chip waveforms. The new signature sets are applied into the multi-rate multi-cell quasi-synchronous CDMA (QS-CDMA) system where each cell is assigned with a GLS set; different users in the same cell are assigned with different GLS sequences in the same GLS set; user’s different streams are assigned with the same GLS sequence but different chip waveforms. According to the properties of GLS sets, the inter-cell interference (ICI) and the multi-user interference (MUI) in the same cell can be reduced significantly. The interferences among different streams of the same user are handled by an optimal (or suboptimal) multi-stream detector(s), notice that the multi-stream detector mentioned here is also named as multi-user detector in other references. We compare the performance of the multi-rate multi-cell QS-CDMA system employing the proposed sets with that of multi-rate system employing well-known concatenated orthogonal/PN sets and that of single-rate system employing GLS sets. The results show that the multi-rate system employing the proposed sets can achieve significant interference reduction. Meanwhile the performance of multi-rate system is similar to that of single-rate system due to the inclusion of multi-user detection.

Analytical EVM, BER, and TD performances of the OFDM systems in the presence of jointly nonlinear distortion and IQ imbalance

The orthogonal frequency-division multiplexing (OFDM) systems are highly sensitive to the nonlinear distortions introduced by the high-power amplifier at the transmitter and to the in-phase and quadrature (IQ) imbalance of the down converter at the receiver. In this paper, the joint effects of these impairments on the performance of the OFDM systems with M signal points quadrature amplitude modulation (M-QAM) are investigated. Moreover, the analytical formulations for the error vector magnitude, the bit error rate, and the total degradation performances of the M-QAM-OFDM systems in additive white Gaussian noise channels as a function of the output back off and IQ imbalance parameters are derived. The computer simulation results confirm the accuracy and validity of our proposed analytical approach.     

Strong Convergence of an Inexact Proximal Point Algorithm in a Banach Space

Journal of Optimization Theory and Applications - By using our own approach, we study the strong convergence of an inexact proximal point algorithm with possible unbounded errors for a maximal...     

Cramer–Rao bound and minimum variance unbiased estimator for joint sampling clock offset and channel taps in MC‐CDMA systems

Exact closed‐form expressions of the Cramer–Rao bound (CRB) for joint sampling clock offset and channel taps are obtained in multi‐carrier code division multiple access systems. CRB is undoubtedly the most well known variance's bound to determine. It provides a benchmark against which we can compare the performance of any unbiased estimator. Furthermore, minimum variance unbiased (MVU) estimator for these parameters is proposed. Moreover, maximum likelihood (ML) and least‐squares estimators for joint sampling clock offset and channel taps are presented. Best linear unbiased estimator is also introduced just for channel taps. The performances of the estimators are compared through simulation results with the proposed CRB. Our results show the better performances of MVU and ML estimators with more computational complexity compared with the others. Copyright © 2008 John Wiley & Sons, Ltd.     

Preserving maximal monotonicity with applications in sum and composition rules

In this paper, we study maximal monotonicity preserving mappings on the Banach space X × X ^*. Indeed, for a maximal monotone set ${M \subset X\times X^*}$ and for a multifunction ${T: X \times X^* \multimap Y \times Y^*}$ , under some sufficient conditions on M and T we show that T(M) is maximal monotone. As two consequences of this result we get sum and composition rules for maximal monotone operators.     

Feed-forward modelling and fuzzy logic based control strategy for powertrain efficiency improvement in a parallel hybrid electric vehicle

With the stricter limitations on both fuel consumption and air pollution, the advantages of a hybrid electric vehicle are becoming more evident than ever. In the present study, an energy management system for a hybrid electric vehicle is developed. Because the plant under consideration is nonlinear, multi-domain, time-varying, has multiple uncertainties and, in addition, the designed control strategy must be able to obey the driver's commands and achieve the par-internship for a new generation of vehicle regulations, the fuzzy logic approach is chosen. A feed-forward hybrid vehicle simulation model is used to demonstrate the validity and the convenience of the current approach and its results have been compared with the other parallel hybrid electric vehicle control strategies. Simulation results show considerable improvement in the efficiency of the internal combustion engine and, consequently, fuel consumption and acceleration performances.     

Sonochemical synthesis and characterization of nano-sized lead(II) 3D coordination polymer: Precursor for the synthesis of lead(II) oxybromide nanoparticles

Nanoparticles of a three-dimensional coordination polymer, [Pb(L)(μ₂-Br)(H₂O)]_n (1), (L^? = 1H-1,2,4-triazole-3-carboxylate), have been synthesized by an ultrasonic method and characterized by scanning electron microscopy, X-ray powder diffraction, IR spectroscopy and elemental analyses. The thermal stability of compound 1 both its bulk and nano-size has been studied by thermal gravimetric (TG) and differential thermal (DTA) analyses and compared each other. Concentration of initial reagents effects and the role of power ultrasound irradiation on size and morphology of nano-structured compound 1, have been studied. Calcination of the compound 1 at 500 °C under air atmosphere yields Pb₃O₂Br₂ nanoparticles.     

Tachyon-polytropic inflation on the brane

We consider the tachyon-brane inflationary universe model in the context of a polytropic gas equation of state. In slow-roll approximation, we discuss general conditions of this model. For exponential potential, in high-energy limit the characteristics of the model are presented. By using the seven-year Wilkinson Microwave Anisotropy Probe (WMAP7) observational data, we constrain the cosmological parameters of the model.     

A new model for automatic normalization of multitemporal satellite images using Artificial Neural Network and mathematical methods

Relative Radiometric Normalization is often required in remote sensing image analyses particularly in the land cover change detection process. Normalization process minimizes the radiometric differences between two images caused by inequalities in the acquisition conditions rather than changes in surface reflectance. A wide range of RRN methods have been developed to adjust linear models. This paper proposes an automated Relative Radiometric Normalization (RRN) method to adjust a non-linear model based on an Artificial Neural Network (ANN) and unchanged pixels. The proposed method includes the following stages: (1) automatic detection of unchanged pixels based on a new idea that uses CVA (Change Vector Análysis) method, PCA (Principal Component Analysis) transformation and K-means clustering technique, (2) evaluation of different architectures of perceptron neural networks to find the best architecture for this specific task and (3) use of the aforementioned network for normalizing the subject image. The method has been implemented on two images taken by the TM sensor. Experimental results confirm the effectiveness of the presented technique in the automatic detection of unchanged pixels and minimizing imaging condition effects (i.e., atmosphere and other effective parameters).