Catálogo de publicaciones - libros

The development of a temperature sensor with a non-linear behaviour is described in this work. The device acts like a thermal switch with hysteresis and is able to return to the initial conditions. Its on-off settings are the passage on fixed temperature that corresponds to the critical temperature (Tc) of thermocromic materials, in this case vanadium dioxide. The final aim is to modify the device switching temperature by changing the thermocromic material critical temperature, following the needs of the specific application.

In this paper we consider a system comprising a highly hysteretic, single Josephson weak link SQUID ring (i.e. where 2π/ ≫ 1 for a SQUID ring inductance and weak link critical current with = /2) coupled to an finite quality factor parallel resonator (tank circuit), the schematic of which is shown in Fig. 1. The non-linear dynamics of this system has been the subject of a great deal of interest both for the quantum and classical operational regimes (see for example [1–3]). In this paper we confine ourselves to the semi-classical Resistively Shunted Junction plus Capacitance (RSJ+C) model of the SQUID ring [4]. For such a SQUID ring-tank circuit system, where the tank circuit is driven by a current , the equations of motion are

We have investigated information transmission in an array of threshold units. Each unit receives a common input signal but independent multiplicative noise. We demonstrate a phenomenon similar to stochastic resonance and suprathreshold stochastic resonance and show that information transmission can be enhanced by a non-zero multiplicative noise level. Given that sensory neurons in the nervous system have multiplicative as well as additive noise sources, and they act approximately like threshold units, our results suggest that multiplicative noise might be benefitial in increasing information transmission in neural populations.

Recently, the authors have developed and demonstrated a novel sensing technology, named SEPTIC (SEnsing of Phage-Triggered Ion Cascades), for the rapid, inexpensive and specific identification of bacteria. The method combines the specificity and fast response of the bacteriophage (“phages”; viruses that specifically detect and kill bacteria) with the sensitivity of the nano-scale fluctuation-enhanced sensing.

Dissipative chemical systems which are having to interact with its environment do not generally see the feeding or removal of species in a uniform or constant manner as is generally taken in simpler form of the theory of an ideal system. There are variations and an expansion of them in Fourier modes can always make some of them vulnerable (or useful if we have some control on it) for the present state of the system. A systematic study of parametric resonance is therefore very important for such systems. Surface wave of fluids generated by vertical oscillation is a well known example where parametric resonance breaks the continuous spatial symmetry [1–3]. In reaction diffusion systems the effect ofparametric resonance has been widely studied to see frequency entrainment and multiphaseoscillation [4–7].

This work aims to simulate potential scenarios in Rainfall-Runoff (R-R) transformation at daily scale, mainly perceived for the control and management of water resources, using feed-forward multilayer perceptrons (MLP) and, subsequently, Jordan Recurrent Neural Networks (JNN). R-R transformation is one of the most complex issue in hydrological environment due to high temporal and spatial variability, very strong and non linear interconnections among variables: a good challenge for Artificial Neural Networks (ANN). Abilities and limitations of MLP and JNN models have been investigated, especially focusing on drought periods where water resources management and control are particulary needed. The study compares the results of the two networks typologies to outputs from a conceptual linear model and then to physical context of two small Ligurian catchments. It also demonstrates the remarkable improvement obtained with the JNN approach especially when rainfall memory effect is employed as an additional input.

The main objective of this paper is to describe a solution to realize online connections between remote workstations placed into different locations. Unidirectional or bidirectional informational transfer has to be guaranteed. Local PCs network or Internet are considered as transmission support. The soft component represented by a LabView virtual instrument will coordinate and control the target communication.

In food processing, the hygienic issues are the most important issues for the health of the consumer; in particular the microbiological safety of cooked food is also regulated by hygienic legislation.

Designing and implementing nonlinear systems, onto hardware devices experiences a paradigm shift with the innovative rapid prototyping system (RPS). The RPS is low cost, commercially off-the-shelf (COTS), and ingeniously establishes a direct path from initial design to a hardware implementation operating in real-time, eliminating several levels of tedious programming for hardware, with automatic code generation. In this paper, the hardware device is a digital signal processor (DSP) embedded in a prototype board. The RPS extends to real-world hardware testing specific to application, from which the nonlinear system design can be revised and optimized. From the RPS, final nonlinear system hardware can be designed with a high level of confidence, and the prototype board can continue to simulate other nonlinear devices.

High-field phenomena in submicron electron devices cannot be described satisfactorily within the framework of the that do not include energy as a dynamical variable and are valid only in the quasi-stationary limit, while most hydrodynamical models suffer from serious theoretical drawbacks due to the treatment of the closure problem [1]. Here we employ a moment approach, previously introduced in [2, 3] (see also [4] for a complete review) in which the closure procedure is based on the maximum entropy principle while the conduction bands are described by the Kane dispersion relation. The electrons in GaAs are considered as a mixture of two fluids, one representing the electrons in the -valley and the other the electrons in the four equivalent -valleys. The model comprises the balance equations of electron density, energy density, velocity and energy flux for both populations, coupled to the Poisson equation for the electric potential.