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This paper shows complex dynamical behavior in an ideal commutable pendulum. This system is set with two regions of different natural frequencies and complex behavior is present by commuting from one region to the other under certain rules. This commutable commutable pendulum shows a very complex behavior besides the fact that it is based on a simple pendulum model. By varying a single parameter in...
The following concepts are discussed: automatic control; nonlinear systems; nonlinear control applications; sliding mode control; nonlinear control design; robotics and synchronisation; optimal control; solar cells; biomedical engineering; communications systems; computer science and computer engineering; mechatronics; solid state materials, electron devices and integrated circuits
This paper deals with the passive/active vibration control problem for damped Duffing systems, using a nonlinear pendulum-type vibration absorber. The primary system is a damped Duffing system affected by exogenous forces with excitation frequencies close to the principal parametric resonance. The design of the (passive) autoparametric vibration absorber is obtained by using an approximation of the...
To simulate the real conditions where the ultrasound will be applied, it is necessary the employment of materials to mimic the ultrasound behavior of tissues; these kind of materials are called phantoms. Therefore, it is important to measure the basic characteristics that must be mimicked; one of them is the ultrasound propagation speed. This characteristic could be employed to estimate the soft tissue...
Using measurement techniques and appropriate models for III-V semiconductor compound transistors we have implemented a large signal model for a commercial LDMOS transistor. Based on this model a 4 Watt UHF class AB power amplifier was simulated and evaluated. The power amplifier was characterized using an aluminum test bench and microstrips. Experimental results shown an output power of 36.3 dBm for...
In this paper a method to perform a smooth three-dimensional reconstruction from a contour map of a terrain is presented. The input data to the proposed method is 3D points of polygonal lines that represent contour maps with the elevation information included; such data is available at INEGI in the case of Mexico. The obtained 3D reconstruction is represented by a triangle mesh. The main idea of the...
This paper describes the prototype for a portable system that records and analyses electrocardiography signals in real time. The purpose of the system is to monitor patients during normal activity to help physicians to diagnose the long QT syndrome and alerts the patient to prevent sudden death. The system consists of a recording system for three leads electrocardiography signals and an algorithm...
In this paper we discuss the practical stability of a class of neutral type time delay systems. We obtain sufficient conditions based on Lyapunov-Krasovskii functionals stated in terms of the feasibility of a set of linear matriz inequalities (LMIpsilas). A ldquopracticalrdquo exponential estimate of the solution is also obtained.
This paper consider the remote control of an unicycle mobile robot subject to transport delay. The communication delay effects are considered by means of a discrete time approach that allows to solve the path tracking problem in terms of the delayed input. The causality problem involved in the proposed solution is carried out by considering an extension to the nonlinear case of the well known Smith...
Catalytic chemical vapor deposition (Cat-CVD), is a new technology to obtain device-quality thin films at low substrate temperatures. In the other hand, the inverted microcrystalline-silicon/crystalline-silicon (muc-Si/c-Si) hetero-junction, consists of a solar cell illuminated on the backside, the c-Si part of the hetero-structure. This, structure configuration avoids the light absorption in the...
The aim of the work was to study the effect of postgrowth thermal annealing processes on the characteristics of the zinc oxide films grown on silicon substrates by dc reactive magnetron sputtering. The growth temperature of the ZnO thin films was fixed at 230degC and then the samples were annealed in dry air atmosphere at 800degC for one hour. The surface of the ZnO samples was analyzed with a scanning...
A cell derives its electrical properties mostly from the electrical properties of its membrane. A membrane, in turn, acquires its properties from its lipids and proteins, such as ion channels and transporters. An electrical potential difference exists between the interior and exterior of cells. A charged object, such an ion, gain or loses energy as it moves between places of different electrical potential,...
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 circumvent...
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 averagerdquo...
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 below Tc and which were identified as the crystalline Ge1Sb4Te7. As...
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...
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...
The present work shows, implementation of neural ICA algorithms with multiple inputs using VHDL Design in a Field Programmable Gate Array (FPGA). We designed an architecture modular using INFOMAX algorithm in order to add n inputs for audio signals. Some simulations results using VHDL are presented using music and voice recorded. The study of performance is made in a net 2times2 and also a net of...
In this paper we present a comparative performance analysis of nine blind signature schemes that have been proposed since 1983 until 2008, spanning a total of 25 years of active research in this topic. We give a short description of all the schemes studied and their main components. This includes customary arithmetic building blocks such as modular exponentiation, elliptic curve scalar multiplication,...
New Advances in mobile computer technology, along with rapid growth of quality and quantity of wireless networks, introduce new capabilities, applications, and concerns to computer science and industry. Unique requirements and constraints of mobile systems bring new challenges to software development for such environments. It demands reconsidering the traditional approaches of information access,...
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