This paper presents a methodology for computation of artificial vector fields that allows a robot to converge to and circulate around generic curves specified in n-dimensional spaces. These vector fields may be directly applied to solve several robotnavigation problems such as border monitoring, surveillance, target tracking, and multirobot pattern generation, with special application to fixed-wing aerial robots, which must keep a positive forward velocity and cannot converge to a single point. Unlike previous solutions found in the literature, the approach is based on fully continuous vector fields and is generalized to time-varying curves defined in n-dimensional spaces. We provide mathematical proofs and present simulation and experimental results that illustrate the applicability of the proposed approach. We also present a methodology for construction of the target curve based on a given set of its samples.

This paper deals with the model-reference control of timed event graphs using the dioid algebra and the residuation theory. It proposes a control structure based on a precompensator and a feedback controller to improve the controlled system performance. It is shown that this approach always leads to an optimal behavior of the closed-loop system. An example is given to illustrate the proposed approach.

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A structured and robust methodology of modeling and simulation can be available through modular stochastic timed Petri nets, including experiments that allow designers to simulate the processes involved in ore production on well-founded estimates. This prerogative guides an experimental research based on real data from an Brazilian open pit mine operation. Three basic simple modules allows to achieve complex models for a real mine. The difference between simulated and measured average productivities are small when compared to an analytic model for the bottleneck and a model implemented in discrete event system language SIMAN, which also validates the simple truck dispatch rule proposed in this paper. As results of the experiment, we derived a valid simulation structure for the open-pit mining process using Petri nets. It was obtained a behavioral evaluation of the efficiency of the structure according to variations in the probability distribution function. INDEX TERMS Design techniques, open pit mines, stochastic experiments, stochastic timed petri nets.

In this paper semirings with an idempotent addition are considered. These algebraic structures are endowed with a partial order. This allows to consider residuated maps to solve systems of inequalities $A \otimes X \preceq B$. The purpose of this paper is to consider a dual product, denoted $\odot$, and the dual residuation of matrices, in order to solve the following inequality $ A \otimes X \preceq X \preceq B \odot X$. Sufficient conditions ensuring the existence of a non-linear projector in the solution set are proposed. The results are extended to semirings of intervals

This paper deals with the state estimation for max-plus linear systems. This estimation is carried out following the ideas of the observer method for classical linear systems. The system matrices are assumed to be known, and the observation of the input and of the output is used to compute the estimated state.The observer design is based on the residuation theory which is suitable to deal with linear mapping inversion in idempotent semiring.