2008 5th International Conference on Electrical Engineering, Computing Science and Automatic Control

In this paper, we study an a priori error analysis for the quadratic optimal control problems governed by nonlinear elliptic partial differential equations using mixed finite element methods. The state and the co-state are approximated by the lowest order Raviart-Thomas mixed finite element spaces and the control is approximated by piecewise constant functions. A priori error estimates for the mix... View full abstract»

In a very recent paper, Zhu et al. [Neural Process Lett (2007)26:191-200] proposed an interesting approach to study pth moment exponential stability of stochastic Cohen-Grossberg neural networks with time-varying delays. Unfortunately, since the constructed Lyapunov function is invalid for p=2k+1, kisinN, the main results obtained are not correct for the general case. This note intends to circumve... View full abstract»

In this paper, robust stabilizing controllers for the synchronous generator speed, series power flows, voltage magnitude and DC link voltage are designed for a power system with FACTS device (UPFC). To design these controllers, a combined super-twisting sliding mode (SM) and block control (BC) technique is implemented. The block control approach is used to design linear and nonlinear sliding manif... View full abstract»

The aim of this work is to investigate the amorphous-to-crystalline phase transformation process in Ge2Sb2Te5 ternary alloys. The experiments were carried out using impedance and X-ray diffraction measurements. The results have shown that the crystallization process in an amorphous Ge2Sb2Te5 alloy starts from nuclei, which appear be... View full abstract»

This paper presents the development of a mecatronic unit EOD/IEDD (explosive ordinance disposal/improvised explosive device disposal), by carrying out a modeling and simulation of a proposed PID control, this unit is applied to perform hazardous-duty operations. The mechatronic unit uses an interchangeable gripper, a robotic arm with 5 degrees of freedom Stanford type, a climbing system and 3 CCD ... View full abstract»

Classic results of the dynamical systems theory are extended and used to study the preservation of synchronization in chaotical dynamical systems. This results show that synchronization can be preserved after changes are made to the linear part of the dynamical system. When the Jacobian matrix of the system is evaluated in the hyperbolic points, the sign structure of the eigenvalues of this matrix... View full abstract»

Spinodal decomposition of the GaSbxNyAs1-x-y quaternary alloys lattice-matched to the GaAs as the result of the internal deformation and coherency strain energies is described. The alloys are represented as quasiternary regular solutions. The internal deformation energy is presented by the interaction parameters between the constituent compounds estimated within th... View full abstract»

Regularized versions of the rdquoProjectional Gradient Techniquerdquo and the ldquoExtraproximal Methodrdquo are suggested to be applied for finding Stackelberg-Nash equilibrium in a multi-participant static game. A comparative between these methods is shown. There exist two levels of hierarchy in decision making: the first one consists of a leader decision and the second one is formed by t... View full abstract»

Some basic concepts related to variable band-gap absorbing semiconductors in solar cell structures such as the associated quasi-electric field will be discussed. The effects of this quasi-electric field upon the minority carrier drift-diffusion length and the back surface recombination velocity will cause a larger generated carrier collection with the corresponding increase of the illumination cur... View full abstract»

We study the statistical nature of the multiuser interference (MUI) from pulse-based ultrawideband (UWB) signals with time-hopping (TH) and pulse position modulation (PPM). We determine the domain of validity for the Gaussian assumption for three different conditions: An ideal propagation channel with perfect and imperfect power control, as well as a multipath channel with rdquoperfect averagerdqu... View full abstract»

A prototype chip for characterization of optical devices is presented based on a simple architecture. This is very useful for the characterization of Phototransistors and photodiodes and also for custom design pixels for image cameras. Phototransistors and photodiodes in a matrix of 6times4, have been used, this is, six rows by four columns. Reading is carried out in the voltage-mode which is diff... View full abstract»

During epilepsy seizure Electrocorticogram (ECoG) may change dramatically from a nearly chaotic signal (basal state) into a highly synchronized signal during a seizure, characterized by high amplitude and low frequency, and suddenly go back to the basal sate, making hard to identify them from time series. The epileptic seizure shows some stages as it is evolving, the here studied are: basal, preic... View full abstract»

Hybrid MIMO communication systems combine spatial multiplexing with diversity gain to achieve both high spectral efficiency and link reliability. We present a novel hybrid scheme that allows the use of any number of spatial multiplexing layers, plus one quasi-orthogonal layer (ABBA) of either 3 or 4 antennas. We transform the system equations in terms of linear dispersion codes, from which we deri... View full abstract»

Cuprous oxide (Cu2O) crystals were grown by the two step crystallization method in air atmosphere conditions from polycrystalline copper plates. The method comprises two stages; in the first one the copper plates are oxidized at 1020degC by some hours in line with its initial thickness. In the second stage the growth of large crystalline areas is promoted by annealing the Cu2... View full abstract»

This paper proposes a simple wireless multi-waveform Urinary Electrical Stimulator (UES) to stimulate electrically patients with urinary incontinence. This system can generate a set of different programmable bipolar and monopolar waveforms, since pulse generator systems most provide different waveforms suitable for each individual patient [1]. This application discloses 6 distinct types of program... View full abstract»

This paper presents a partial state feedback controller for an active rectifier to regulate dc output voltage and to guarantee a power factor close to unity. The partial information controller is based on the Exact Tracking Error Dynamics Passive Output Feedback (ETDPOF) technique in conjunction with an Immersion and Invariance based inductor current observer. Numerical simulations are presented t... View full abstract»

The main aim of this paper is to comment about the difficulties encountered during the implementation of a well known analytic leak detection algorithm on a short length water pipeline prototype. In addition, the proposed solutions to overcome these difficulties are described. To improve the algorithm, extra filtering to all input signals is added and a freezing-method for the friction coefficient... View full abstract»

The objective of this work is to create a theoretical model and to conduct the detail research of the electromagnetic radiation interaction with granular product and insects. The theoretical research on the electromagnetic wave interaction with granular agricultural product and insects is done in the present work through the solving of electromagnetic boundary problem [1]. It is well-known that bo... View full abstract»

In this paper we introduce a reversible data hiding algorithm for medical images. Using the advantages of some proved methods and the characteristics of radiological medical images we obtain a large embedding capacity with minimum distortion of the original image using an easy control for recovering the hidden data and the original image. View full abstract»

A genetic-type-2 fuzzy logic controller (FLC) is proposed to achieve the output regulation of a servomechanism with backlash. The problem is the design of a type-2 FLC, which will be optimized by a genetic algorithm (GA) to obtain the closed-loop system in which the load of the driver is regulated to a desired position. The provided servomotor position is the only measurement available for feedbac... View full abstract»

The present work proposes an electronic waveform generator for transcorneal electrical stimulation (TES). The applied waveform model is generated into a digital processor by means of an adaptive finite impulse response (FIR) filter, which output waveform is synthesized from the original one registered using a multi-focal electroretinograph (MF-ERG). The stimulation waveform applied in patients wit... View full abstract»

This paper deals with an analysis of techniques of interleaved Echo-Planar imaging (EPI) method for Functional Magnetic Resonance Imaging (fMRI). In order to have optimum echo time and consequently achieving low image distortion, an approach has been emphasized upon a technique that acquires six images, each with a different echo time, in a single shot. Also investigation has been initiated for th... View full abstract»

This paper presents a methodology for closed-loop identification of velocity controlled servomotors. The approach considers a PI controller applied simultaneously to the real servomotor and its model. It is shown that under persistently exciting conditions the parameter estimates converges. Experimental results using a laboratory test bed validate the proposed approach. View full abstract»

This paper has as principal objective to determine the value of some parameters of light that are determinants in the activation or inhibition of the growth stimulus of wheat seeds (Triticum aestivum L). In this case intensity and dose, as important parameters, were considered. GaAlAs laser with lambda=850 nm was used to irradiate the biological system. The growth of main shoot was considered. All... View full abstract»

This work describes a Web search approach taking into account the semantic content of Web pages. Eliminating irrelevant Web pages, the time-consuming task of revise the obtained results from actual search engines is reduced. The proposed approach is focused on Web pages that are not defined with semantic Web structure (most of the actual Web pages are in this format). The challenge is extract the ... View full abstract»