Madalena Chaves

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In this paper we will consider a network of vehicles exchanging information among themselves with the intention of achieving a specified polygonal formation. A stochastic model for information transmission and reception is considered , allowing for the randomly breaking of the communication links among the vehicles. The network achieves the formation(More)
In this paper, the study of the class of biochemical systems known as zero deficiency networks is extended to the case of time-varying kinetic parameters. We show that the resulting class of nonlinear systems with inputs satisfies a notion of input-to-state stability uniformly over a set of parameters. In particular, the input-to-state stability estimates(More)
A commonly employed measure of the signal amplification properties of an input/output system is its induced L 2 norm, sometimes also known as H ∞ gain. In general, however, it is extremely difficult to compute the numerical value for this norm, or even to check that it is finite, unless the system being studied is linear. This paper describes a class of(More)
This contribution provides an overview of our work on modelling biological processes focussing on the example of programmed cell death, also called apoptosis. Apoptosis is a molecular programme present in all cells of multi-cellular organisms. It is crucial during development and for cell homoeostasis in the adult. Misregu-lation is implicated in severe(More)
A qualitative method to control piecewise affine differential systems is proposed and explored for application to genetic regulatory networks. This study considers systems whose outputs and inputs are of a qualitative form, well suited to experimental devices: the measurements indicate whether the variables are " strongly " or " weakly " expressed, that is,(More)
The dynamics of Boolean networks can be represented by asynchronous transition graphs, whose attractors describe the system's asymptotic behavior. This paper shows that the attractors of the feedback interconnection of two Boolean modules can be fully identified in terms of cross-products of the attractors of each module. Based on this observation, a model(More)
The dynamics of the interconnection of two Boolean networks is analyzed directly from the properties of the two individual modules. Motivated by biological systems where multiple timescales are present, we consider asynchronous Boolean networks, whose dynamics can be described by non-deterministic transition graphs. Two new objects are introduced, the(More)