Supervised Multi‐Rejector of Periodic Disturbances for Nonlinear Systems Using Decoupled State Multimodel

In this paper, a multi‐rejector of periodic disturbances is proposed for discrete‐time nonlinear systems represented by a decoupled state multimodel. We report a decoupled state multimodel repetitive‐predictive control based on a supervised algorithm to ensure reference trajectory tracking and periodic disturbances rejection. Partial predictors associated to the local controllers make the best choice of the most valid partial controller that meets the desired closed loop performances. The effectiveness of the supervised multi‐rejector is shown via a simulation example. The obtained results are satisfactory and show a good rejection of periodic disturbances and reference trajectory tracking.     

Self-stabilizing algorithm for high service availability in spite of concurrent topology changes in ad hoc mobile networks

Mobile nodes in ad hoc networks move freely and run out of battery power so quickly, which leads to frequent network partitioning. Network partitioning considerably reduces service availability when the server node is not in the same partition as the client nodes. In order to provide a continuous service availability for all mobile nodes, we propose a self-stabilizing algorithm that can tolerate multiple concurrent topological changes and can incur a cost of one server per long-lived connected component. By using (1) the time interval-based computations concept that distinguishes between disjoint and concurrent computations, and (2) Markov chain model, the proposed algorithm can within a finite time converge to a legitimate state even if topological changes occur during the convergence time. Our simulation results show that the algorithm can ensure very high service availability, and each node has a strong path to the server of its network component over 98% of the time.     

Efficient data aggregation with in-network integrity control for WSN

Energy is a scarce resource in Wireless Sensor Networks (WSN). Some studies show that more than 70% of energy is consumed in data transmission in WSN. Since most of the time, the sensed information is redundant due to geographically collocated sensors, most of this energy can be saved through data aggregation. Furthermore, data aggregation improves bandwidth usage and reduces collisions due to interference. Unfortunately, while aggregation eliminates redundancy, it makes data integrity verification more complicated since the received data is unique.     

An analysis of the transition proportion for binarization in handwritten historical documents

In this paper, we will present a mathematical analysis of the transition proportion for the normal threshold (NorT) based on the transition method. The transition proportion is a parameter of NorT which plays an important role in the theoretical development of NorT. We will study the mathematical forms of the quadratic equation from which NorT is computed. Through this analysis, we will describe how the transition proportion affects NorT. Then, we will prove that NorT is robust to inaccurate estimations of the transition proportion. Furthermore, our analysis extends to thresholding methods that rely on Bayes rule, and it also gives the mathematical bases for potential applications of the transition proportion as a feature to estimate stroke width and detect regions of interest. In the majority of our experiments, we used a database composed of small images that were extracted from DIBCO 2009 and H-DIBCO 2010 benchmarks. However, we also report evaluations using the original (H-)DIBCO?s benchmarks.     

Performance evaluation and implementation complexity analysis framework for ZF based linear massive MIMO detection

Wireless Networks - This paper discusses a framework for algorithm-architecture synergy for (1) performance evaluation and (2) FPGA implementation complexity analysis of linear massive MIMO...     

Electrophoretic impregnation of porous anodizing layer by synthesized TiO<Subscript>2</Subscript> nanoparticles

This paper deals with the elaboration of a stable suspension of TiO₂ nanoparticles and their incorporation by electrophoretic deposition into pores of an anodized 5754 aluminum alloy. The as-synthesized TiO₂ nanopowder was characterized by the X-ray diffraction, scanning and transmission electron microscopy, energy dispersive X-ray spectroscopy and IR spectroscopy. During this work, both the transmission electron microscopy and particle analysis showed that the resulting particles had a narrow size distribution with a crystallite size of about 15 nm. The zeta potential and stability of TiO₂ nanoparticles dispersed with poly(acrylic acid) in an aqueous solution were also measured. A porous anodic film was synthesized in the phosphoric acid-base electrolyte and then filled by 15 nm TiO₂ particles via electrophoresis. In addition, the effect of poly(acrylic acid) and pH on the suspension stability has been investigated. It was also demonstrated that by adding glycine in buffered suspension gelating phenomenon can be avoided that inhibits the insertion of nanoparticles inside the pores of an anodic film. It was also noted that an applied electric field greatly influences the electrophoretic deposition process. The field emission gun-scanning electron microscopy observations showed that larger (125 nm in diameter) and linear (6 μm in length) pores are successfully filled in 5 min.     

Impact of the Cd2+ treatment on the electrical properties of Cu2ZnSnSe4 and Cu(In,Ga)Se2 solar cells

The present contribution aims at determining the impact of modifying the properties of the absorber/buffer layer interface on the electrical performance of Cu₂ZnSnSe₄ (CZTSe) thin‐film solar cells, by using a Cd²⁺ partial electrolyte (Cd PE) treatment of the absorber before the buffer layer deposition. In this work, CZTSe/CdS solar cells with and without Cd PE treatment were compared with their respective Cu(In,Ga)Se₂ (CIGSe)/CdS references. The Cd PE treatment was performed in a chemical bath for 7 min at 70 °C using a basic solution of cadmium acetate. X‐ray photoemission spectroscopy measurements have revealed the presence of Cd at the absorber surface after the treatment. The solar cells were characterized using current density–voltage (J–V), external quantum efficiency, and drive‐level capacitance profiling measurements. For the CZTSe‐based devices, the fill factor increased from 57.7% to 64.0% when using the Cd PE treatment, leading to the improvement of the efficiency (η) from 8.3% to 9.0% for the best solar cells. Similar observations were made on the CIGSe solar cell reference. This effect comes from a considerable reduction of the series resistance (R_S) of the dark and light J–V, as determined using the one‐diode model. The crossover effect between dark and light J–V curves is also significantly reduced by Cd PE treatment. Copyright © 2015 John Wiley & Sons, Ltd.     

Combining formant frequency based on variable order LPC coding with acoustic features for TIMIT phone recognition

Combination of multiple acoustic features has great potential to improve Automatic Speech Recognition (ASR) accuracy. Our contribution in this research was to investigate one novel method when using voiced formants’ features in combination with standard MFCC features in order to enhance TIMIT phone recognition. These voiced features provide accurate formants frequencies using a Variable Order LPC Coding (VO-LPC) algorithm that was combined with continuity constraints. The overall estimating formants were concatenated with MFCC features when a voiced frame could be detected. For feature-level combination, Heteroscedastic Linear Discriminant Analysis (HLDA) based approach had been used successfully to find an optimal linear combination of successive vectors of a single feature stream.     

On eliminating packet droppers in MANET: A modular solution

In this paper we deal with misbehaving nodes in mobile ad hoc networks (MANETs) that drop packets supposed to be relayed, whose purpose may be either saving their resources or launching a DoS attack. We propose a new solution to monitor, detect, and safely isolate such misbehaving nodes, structured around five modules: (i) The monitor, responsible for controlling the forwarding of packets, (ii) the detector, which is in charge of detecting the misbehaving of monitored nodes, (iii) the isolator, basically responsible for isolating misbehaving nodes detected by the detector, (iv) the investigator, which investigates accusations before testifying when the node has not enough experience with the accused, and (v) finally the witness module that responds to witness requests of the isolator. These modules are based on new approaches, aiming at improving the efficiency in detecting and isolating misbehaving nodes with a minimum overhead. We describe these modules in details, and their interactions as well. We also mathematically analyze our solution and assess its performance by simulation, and compare it with the watchdog, which is a monitoring technique employed by almost all the current solutions.