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In this paper we investigate the degradation of the statistic properties of chaotic maps as consequence of their implementation in a digital media such as Digital Signal Processors (DSP), Field Programmable Gate Arrays (FPGA) or Application-Specific Integrated Circuits (ASIC). In these systems, binary floating- and fixed-point are the numerical representations available. Fixed-point representation is preferred over floating-point when speed, low power and/or small circuit area are necessary. Then, in this paper we compare the degradation of fixed-point binary precision version of chaotic maps with the one obtained by using floating point 754-IEEE standard, to evaluate the feasibility of their FPGA implementation. The specific period that every fixed-point precision produces was investigated in previous reports. Statistical characteristics are also relevant, it has been recently shown that it is convenient to describe the statistical characteristic using both, causal and non-causal quantifiers. In this paper we complement the period analysis by characterizing the behavior of these maps from an statistical point of view using cuantifiers from information theory. Here, rather than reproducing an exact replica of the real system, the aim is to meet certain conditions related to the statistics of systems. Fil: Antonelli, Maximiliano. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Científicas y Tecnológicas en Electrónica. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones Científicas y Tecnológicas en Electrónica; Argentina Fil: de Micco, Luciana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Científicas y Tecnológicas en Electrónica. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones Científicas y Tecnológicas en Electrónica; Argentina Fil: Larrondo, Hilda Angela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Científicas y Tecnológicas en Electrónica. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones Científicas y Tecnológicas en Electrónica; Argentina Fil: Rosso, Osvaldo Aníbal. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidade Federal de Alagoas; Brasil. Hospital Italiano; Argentina. Universidad de Los Andes; Chile

Additive White Gaussian Noise (AWGN) generators are a basic tool for the test and measurement of digital systems. One drawback for hardware implementation of the classically used algorithms is that they require the hardware implementation of complex operations (such as sinusoidal and logarithmic functions). In this chapter, a method for the design and hardware implementation of an AWGN generator based on chaotic maps is described. The advantage is that deterministic chaotic systems are described by simple nonlinear equations, and therefore, they are straightforward to implement in hardware. To ensure that the generated sequence has the desired Probability Density Function (PDF), the chaotic map, which is the heart of the system, is synthesized using an approach based on the theory of positive matrices method. The hardware implementation was developed using an Altera Cyclone III FPGA with the 3C120 Development Board.

The appearance of a maximum in the intensity of scattered light at a nonzero wave vector for systems undergoing a polymerization-induced phase separation (PIPS) has been considered in the past as conclusive evidence of the presence of a spinodal demixing mechanism. However, recent results from light scattering studies of colloidal aggregation and phase separation in aqueous biopolymers systems and polymer blends prove that the maximum may also be generated by a nucleation-growth process (NG). The origin of this scattering behavior is the presence of a layer surrounding dispersed-phase particles that contains less solute concentration than the bulk (depletion layer). We apply this concept to a system undergoing PIPS through an NG mechanism. The analysis is constrained to the generation of a diluted dispersion of spherical particles where concentration profiles around particles may be analytically derived. Both Rayleigh−Gans and Mie scattering theories are used to describe the patterns of scattered light. I...

Any incident plane polarized beam, after travelling through the fiber, will emerge in a state of general elliptic polarization. The size and shape of the ellipse will depend critically on the total path travelled inside the fiber, which in turn is related to the stresses applied to it. By analyzing the emerging light with a polarizer, one can detect even tiny variations in the fiber length. Using this method in a commercial fiber together with inexpensive equipment, the breaking of individual wires in a multiwired steel rope is detected

In this paper a hardware implementation of a Maximum Lyapunov Exponent (MLE) quantifier is designed and implemented using a field programmable gate array (FPGA). The design was optimized in terms of accuracy employing floating point architecture to represent the values. The proposed design takes advantage of the underline parallelism of the MLE computation equations and allows its concurrent implementation based on FPGA technology.

Methods for evaluating the structural health of mechanical cables and detecting their imminent failure could prevent the loss of valuable equipment and, more importantly, the possible loss of human life. The non-destructive test methods available are: thorough visual examination and measurement of the external diameter; X-rays; (induced) wave propagation; acoustic emission; magnetostrictive sensors; infrared detection. A new method which employs a commercial optical fiber for detecting the breakage of individual wires in a rope is proposed in the present paper.

This paper presents some numerical experiments performed on transverse vibrations and the elastic stability of homogeneous, isotropic, clamped circular plates of discontinuously varying thickness. The purpose of the study is threefold: (1) to determine dynamic stiffening situations; (2) to experiment on the effect of optimization with respect to an exponential parameter (non-integer version of the Rayleigh-Ritz method or the ‘optimized Rayleigh-Ritz method’) as opposed to the classical version of the energy method; and (3) to ascertain the relative accuracy of the optimized Rayleigh-Ritz method by comparing eigenvalues determined using this technique and those calculated using a very efficient standard finite element code.

The dual deterministic-stochastic behavior of chaotic systems (CS) makes them extremely interesting in electronic engineering as CS may replace noise sources in different applications. Consequently it is convenient to have hardware implementations for both, analog and digital versions. Discrete components, Micro Controllers, Digital Signal Processors (DSP) and Field Programmable Gate Arrays (FPGAs) are possible choices.

An exact solution of the title problem is presented. The overall situation is of great interest in many engineering applications. Three combinations of boundary conditions for the structural element are considered: simply supported, simply supported - clamped and clamped at both ends. An analysis of the situation where the spring-mass system acts as a dynamic absorber cancelling out the motion at the point of attachment for certain modes of vibration is presented. An independent solution has also been obtained by means of a finite element code in order to ascertain the validity and accuracy of the results predicted by the exact solution of Timoshenko's dynamic differential system.

A large number of papers and technical reports are available on the technically important problem of structural elements executing transverse vibrations and carrying concentrated masses. In general it is assumed that the attachment is perfectly rigid. On the other hand, a rather limited amount of published work is available when the mass is elastically connected to the structure. The system then exhibits a more complex behavior than in the case of rigid attachment. The present study deals with the solution of the title problem using the well-known normal mode, sinusoidal eigenfunction expansions.

Civil, naval and ocean engineers are frequently confronted with the problem of mounting dynamic, operational units on structural elements. The designer must be able to determine natural frequencies of the coupled system: structure-motor or engine and its elastic mounting. Frequency coefficients are obtained in the present study for three combinations of boundary conditions: simply supported; simply supported and clamped at both ends.

In this paper finite sequences, known as Pseudo Noise codes (PN‐codes) are studied. PN‐codes are used in Spread Spectrum Digital Systems (SSDS), a widely employed wireless communication technique. The selection of the best “set of PN‐codes” (PN‐family) is an important issue in SSDS. This selection is based on a very involved statistical analysis. This paper presents three contributions in this field: the first contribution is the definition of new global quantifiers instead of those used in the engineering literature. The second contribution is to show that a quantifier based on the Zipping Complexity Measure may be a global optimization quantifier of the whole system. Finally a comparison between usual PN‐families and chaotic generated PN‐families is presented, showing that chaotic systems are competitive in this application field.

A chaotic communication system based on standard digital signal processing (DSP) boards is presented. It consists of two chaotic oscillators synchronised in an active passive decomposition scheme. It is more versatile and easier to synchronise than its analogue counterpart and allows the control of the information signal bandwidth by software.

The present note deals with an approximate solution of the title problem in the case where a portion of the plate is subject to a p o cos ωt-type excitation. The lower natural frequency coefficients and dimensionless values of displacements and stress resultants are determined for several combinations of the mechanical parameters coming into play.