Recursive Least-Squares Estimation for the Joint Input-State Estimation of Linear Discrete Time Systems with Unknown Input

This paper presents a recursive least-squares approach to estimate simultaneously the state and the unknown input of linear time varying discrete time systems with unknown input. The method is based on the assumption that no prior knowledge about the dynamical evolution of the input is available. The joint input and state estimation are obtained by recursive least-squares formulation by applying the inversion lemmas. The proposed filter is equivalent to recursive three step filter. To illustrate the performance of the proposed filter an example is given

Modeling of permanent magnet linear generator and state estimation based on sliding mode observer: A wave energy system application

summary:This paper synopsis a new solution for Permanent Magnets Linear Generator (PMLG) state estimation subject to bounded uncertainty. Therefore, a PMLG modeling method is presented based on an equivalent circuit, wherein a mathematical model of the generator adapted to wave energy conversion is established. Then, using the Linear Matrix Inequality (LMI) optimization and a Lyapunov function, this system's Sliding Mode Observer (SMO) design method is developed. Consequently, the proposed observer can give a robust state estimation. At last, numerical examples with and without uncertainty are included to exemplify the effectiveness and applicability of the suggested approaches

Contribution of cellular automata to the understanding of corrosion phenomena

We present a stochastic CA modelling approach of corrosion based on spatially separated electrochemical half-reactions, diffusion, acido-basic neutralization in solution and passive properties of the oxide layers. Starting from different initial conditions, a single framework allows one to describe generalised corrosion, localised corrosion, reactive and passive surfaces, including occluded corrosion phenomena as well. Spontaneous spatial separation of anodic and cathodic zones is associated with bare metal and passivated metal on the surface. This separation is also related to local acidification of the solution. This spontaneous change is associated with a much faster corrosion rate. Material morphology is closely related to corrosion kinetics, which can be used for technological applications.Comment: 13 pages, 9 figure

Robust Filtering for State and Fault Estimation of Linear Stochastic Systems with Unknown Disturbance

This paper presents a new robust filter structure to solve the simultaneous state and fault estimation problem of linear stochastic discrete-time systems with unknown disturbance. The method is based on the assumption that the fault and the unknown disturbance affect both the system state and the output, and no prior knowledge about their dynamical evolution is available. By making use of an optimal three-stage Kalman filtering method, an augmented fault and unknown disturbance models, an augmented robust three-stage Kalman filter (ARThSKF) is developed. The unbiasedness conditions and minimum-variance property of the proposed filter are provided. An illustrative example is given to apply this filter and to compare it with the existing literature results

Optimal Germination Temperature Assessed by Indices and Models in Field Bean (Vicia faba L. var. minor)

This paper seeks to shed light on the effect of temperature on field bean (Vicia faba L. var. minor) germination and root elongation. Accordingly, the results were as follows: germination was faster at 20°C than at 5, 10, 15, 25 or 30°C. However, temperature had no effect on total germination percentage between 10 and 30°C, although it was reduced by approximately 4% at 5°C and delayed at other temperatures. 50% germination required nine days at 5°C but only three days at 20°C. Seeds required a mean germination time of 12 days for total germination at 5°C but only four days at 20°C. The coefficient of the velocity or rate of germination index reached the highest (23.71%) and lowest (8.24%) value at 20°C and 5°C, respectively. Maximum germination speed (43.26), as assessed by the speed of germination index, was at 20°C. The speed of accumulated germination grew in proportion to the increase in incubation temperature. Th e main root axis length index and root elongation speed peaked at 20°C (five days and 0.72 cm/day, respectively). Prediction of optimal temperature for germination (To) by using the equation D = [a-(b×T) +(c×T2)] showed that 20°C is the optimum To, indicating that the theoretical model was robust. Hence, it could confidently be used to calculate all parameters related to the effect of temperature on faba bean germination