10,439 research outputs found
Multi-loop position analysis via iterated linear programming
Robotics: Science and Systems Conference (RSS), 2006, Filadelfia (EE.UU.)This paper presents a numerical method able to isolate all configurations that an arbitrary loop linkage can adopt, within given ranges for its degrees of freedom. The procedure is general, in the sense that it can be applied to single or multiple intermingled loops of arbitrary topology, and complete, in the sense that all possible solutions get accurately bounded, irrespectively of whether the analyzed linkage is rigid or mobile. The problem is tackled by formulating a system of linear, parabolic, and hyperbolic equations, which is here solved by a new strategy exploiting its structure. The method is conceptually simple, geometric in nature, and easy to implement, yet it provides solutions at the desired accuracy in short computation times.This work was supported by the project 'Planificador de trayectorias para sistemas robotizados de arquitectura arbitraria' (J-00930).Peer Reviewe
SecDec-3.0: numerical evaluation of multi-scale integrals beyond one loop
SecDec is a program which can be used for the factorization of dimensionally
regulated poles from parametric integrals, in particular multi-loop integrals,
and the subsequent numerical evaluation of the finite coefficients. Here we
present version 3.0 of the program, which has major improvements compared to
version 2: it is faster, contains new decomposition strategies, an improved
user interface and various other new features which extend the range of
applicability.Comment: 46 pages, version to appear in Comput.Phys.Com
Two-Loop integrals for CP-even heavy quarkonium production and decays: Elliptic Sectors
By employing the differential equations, we compute analytically the elliptic
sectors of two-loop master integrals appearing in the NNLO QCD corrections to
CP-even heavy quarkonium exclusive production and decays, which turns out to be
the last and toughest part in the relevant calculation. The integrals are found
can be expressed as Goncharov polylogarithms and iterative integrals over
elliptic functions. The master integrals may be applied to some other NNLO QCD
calculations about heavy quarkonium exclusive production, like
, ,~and~, heavy quarkonium exclusive
decays, and also the CP-even heavy quarkonium inclusive production and decays.Comment: 23 pages, 3 figures, more discussions and references adde
The Lazy Flipper: MAP Inference in Higher-Order Graphical Models by Depth-limited Exhaustive Search
This article presents a new search algorithm for the NP-hard problem of
optimizing functions of binary variables that decompose according to a
graphical model. It can be applied to models of any order and structure. The
main novelty is a technique to constrain the search space based on the topology
of the model. When pursued to the full search depth, the algorithm is
guaranteed to converge to a global optimum, passing through a series of
monotonously improving local optima that are guaranteed to be optimal within a
given and increasing Hamming distance. For a search depth of 1, it specializes
to Iterated Conditional Modes. Between these extremes, a useful tradeoff
between approximation quality and runtime is established. Experiments on models
derived from both illustrative and real problems show that approximations found
with limited search depth match or improve those obtained by state-of-the-art
methods based on message passing and linear programming.Comment: C++ Source Code available from
http://hci.iwr.uni-heidelberg.de/software.ph
Performance-oriented model learning for data-driven MPC design
Model Predictive Control (MPC) is an enabling technology in applications
requiring controlling physical processes in an optimized way under constraints
on inputs and outputs. However, in MPC closed-loop performance is pushed to the
limits only if the plant under control is accurately modeled; otherwise, robust
architectures need to be employed, at the price of reduced performance due to
worst-case conservative assumptions. In this paper, instead of adapting the
controller to handle uncertainty, we adapt the learning procedure so that the
prediction model is selected to provide the best closed-loop performance. More
specifically, we apply for the first time the above "identification for
control" rationale to hierarchical MPC using data-driven methods and Bayesian
optimization.Comment: Accepted for publication in the IEEE Control Systems Letters (L-CSS
- …