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The article in the Spanish Journal of Physics focuses on the tribute to José Manuel Casado Vázquez and Manuel Morillo Buzón, professors of Theoretical Physics at the University of Seville. It highlights José Manuel's academic contributions in kinetic theory and numerical methods, as well as his passion for literature and photography. On the other hand, it emphasizes Manuel's research in stochastic and quantum systems, his international collaboration, and his teaching work. Both left a significant legacy in the academic community. [Extracted from the article]

This work presents an application of the Risk-Sensitive (R-S) control with tracking applied to a stochastic nonlinear system which models the operation of an electronic expansion valve (EEV) in a conventional evaporator. A novel dynamical stochastic equation represents the mathematical model of the evaporator system. The R-S stochastic optimal problem consists of the design of an optimal control u(t) such that the state reaches setpoint values (SP) and minimizes the exponential quadratic cost function. The presence of disturbances and errors in the sensor measurements is represented by Gauss white noise in the state equation, with the coefficient ... One novel characteristic in this proposal is that the coefficient of the control into the state equation contains the state term. The error and exponential quadratic cost function show that the R-S control has a better performance versus the classical PID (Proportional, Integral Derivative) control, applying different tuning methodologies. [ABSTRACT FROM AUTHOR]

This paper proposes the use of random noise signals for the determination of the seismometers and accelerometers frequency response, as part of a device for device calibration which are the fundamental part of seismometric channel. The theory of the method is presented including mathematical relationship, considering these sensors as linear time invariant system (LTI) excited by stochastic signals and calculating the frequency response using these signals as a function of the Power Spectral Densities (PSD). Also, the main relationships and input - output equations defining the frequency response of these systems are shown and finally presented, for example, the calibration of very broad band sensor which is use extensive in seismic networks at national and international level. [ABSTRACT FROM AUTHOR]

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Simulation is used when the stochastic system is too complex to be analyzed satisfactorily through analytic-mathematical models. In this research, the simulation was used to show the impact of the ergonomic redesigns at the workstations in a conveyor. To simulate this system, a preliminary analysis of the workstations was made in the order to collect useful information to design a logic model. This model was simulated and changed according to the ergonomic redesign of the workstations. The results proved the usefulness of simulation for predicting and analyzing the impact of the implemented propositions. [ABSTRACT FROM AUTHOR]

We describe the maximum likelihood method as a mechanism for estimating parameters in stochastic differential equations used to describe the behavior of financial variables. Are considered special cases of the Black-Scholes model and Vasicek, for which estimates are derived parameters that determine them. [ABSTRACT FROM AUTHOR]

Copyright of Archivos de Medicina Veterinaria is the property of Universidad Austral de Chile, Facultad de Ciencias Veterinarias and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A novel algorithm is presented for the optimal estimation of parameters and for determining the initial conditions in non linear mathematical models. The work was developed based on models derived from property balance equations. A matrix relation between the variation of degrees of freedom of the process and the variations of the input variables was used to formulate the objective function, which was optimized via orthogonal projection methods. The technique was applied to a continuous stirred tank reactor obtaining results that were consistent with the dynamic behavior of the reactor. [ABSTRACT FROM AUTHOR]