334 research outputs found
Embedded SLAM algorithm based on ORB-SLAM2
The goal of this dissertation was to present a comprehensive analysis of the ORB-SLAM2 algorithm. By introducing the basis of points triangulation and ORB features, the whole structure of the algorithm has been analyzed, with a centralized focus on the graph-based optimization involved, as well as the place recognition mechanism. Additionally, the original code has been analyzed and optimized, resulting in a substantial increase in time performance while keeping a similar accuracy to the original one, proved by several simulations performed. The final goal of this thesis has been the testing of the obtained algorithm on a real quadcopter and the analysis of its outcomes: the results were affected by the limited computational resources available in the vehicle, obtaining a lower accuracy with respect to the simulation, but still proving the efficiency of the improvements applied on the original code
Highly Automated Formal Verification of Arithmetic Circuits
This dissertation investigates the problems of two distinctive formal verification techniques for verifying large scale multiplier circuits and proposes two approaches to overcome some of these problems. The first technique is equivalence checking based on recurrence relations, while the second one is the symbolic computation technique which is based on the theory of Gröbner bases. This investigation demonstrates that approaches based on symbolic computation have better scalability and more robustness than state-of-the-art equivalence checking techniques for verification of arithmetic circuits. According to this conclusion, the thesis leverages the symbolic computation technique to verify floating-point designs. It proposes a new algebraic equivalence checking, in contrast to classical combinational equivalence checking, the proposed technique is capable of checking the equivalence of two circuits which have different architectures of arithmetic units as well as control logic parts, e.g., floating-point multipliers
On probabilistic capacity maximization in a stationary gas network
The question for the capacity of a given gas network, i.e., determining the maximal amount of gas that can be transported by a given network, appears as an essential question that network operators and political administrations are regularly faced with. In that context we present a novel mathematical approach to assist gas network operators in managing uncertainty with respect to the demand and in exposing free network capacities while increasing reliability of transmission and supply. The approach is based on the rigorous examination of optimization problems with nonlinear probabilistic constraints. As consequence we deal with solving an optimization problem with joint probabilistic constraints over an infinite system of random inequalities. We will show that the inequality system can be reduced to a finite one in the situation of considering a tree network topology. A detailed study of the problem of maximizing free booked capacities in a stationary gas network is presented that comes up with an algebraic model involving Kirchhoff's first and second laws. The focus will be on both the theoretical and numerical side. We are going to validate a kind of rank two constraint qualification implying the differentiability of the considered capacity problem. At the numerical side we are going to solve the problem using a projected gradient decent method, where the function and gradient evaluations of the probabilistic constraints are performed by the approach of spheric-radial decomposition applied for multivariate Gaussian random variables and more general distributions
On probabilistic capacity maximization in a stationary gas network
The question for the capacity of a given gas network, i.e., determining
the maximal amount of gas that can be transported by a given network, appears
as an essential question that network operators and political administrations
are regularly faced with. In that context we present a novel the demand and
in exposing free network capacities while increasing reliability of
transmission and supply. The approach is based on the rigorous examination of
optimization problems with nonlinear probabilistic constraints. As
consequence we deal with solving an optimization problem with joint
probabilistic constraints over an infinite system of random inequalities. We
will show that the inequality system can be reduced to a finite one in the
situation of considering a tree network topology. A detailed study of the
problem of maximizing free booked capacities in a stationary gas network is
presented that comes up with an algebraic model involving Kirchhoffs first
and second laws. The focus will be on both the theoretical and numerical
side. We are going to validate a kind of rank two constraint qualification
implying the differentiability of the considered capacity problem. At the
numerical side we are going to solve the problem using a projected gradient
decent method, where the function and gradient evaluations of the
probabilistic constraints are performed by the approach of spheric-radial
decomposition applied for multivariate Gaussian random variables and more
general distributions
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