Capturability analysis of the linear inverted pendulum (LIP) model enabled walking with constrained height based on the capture point. We generalize this analysis to the variableheight inverted pendulum (VHIP) and show how it enables 3D walking over uneven terrains based on capture inputs. Thanks to a tailored optimization scheme, we can compute these inputs fast enough for real-time model predictive control. We implement this approach as open-source software and demonstrate it in dynamic simulations.
We call a random point measure infinitely ramified if for every n ∈ N, it has the same distribution as the n-th generation of some branching random walk. On the other hand, branching Lévy processes model the evolution of a population in continuous time, such that individuals move in space independently, according to some Lévy process, and further beget progenies according to some Poissonian dynamics, possibly on an everywhere dense set of times. Our main result connects these two classes of processes much in the same way as in the case of infinitely divisible distributions and Lévy processes: the value at time 1 of a branching Lévy process is an infinitely ramified point measure, and conversely, any infinitely ramified point measure can be obtained as the value at time 1 of some branching Lévy process.
In this article, we study a branching random walk in an environment which
depends on the time. This time-inhomogeneous environment consists of a sequence
of macroscopic time intervals, in each of which the law of reproduction remains
constant. We prove that the asymptotic behaviour of the maximal displacement in
this process consists of a first ballistic order, given by the solution of an
optimization problem under constraints, a negative logarithmic correction, plus
stochastically bounded fluctuations.Comment: 42 pages, 7 figures, article updated to correct a mistake in the
proof of Lemma 3.
We propose an analysis and applications of sample pooling to the epidemiologic monitoring of COVID-19. We first introduce a model of the RT-qPCR process used to test for the presence of virus in a sample and construct a statistical model for the viral load in a typical infected individual inspired by large-scale clinical datasets. We present an application of group testing for the prevention of epidemic outbreak in closed connected communities. We then propose a method for the measure of the prevalence in a population taking into account the increased number of false negatives associated with the group testing method.
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