3,809 research outputs found

    Using RBF nets in rubber industry process control

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    This paper describes the use of a radial basis function (RBF) neural network. It approximates the process parameters for the extrusion of a rubber profile used in tyre production. After introducing the problem, we describe the RBF net algorithm and the modeling of the industrial problem. The algorithm shows good results even using only a few training samples. It turns out that the „curse of dimensions“ plays an important role in the model. The paper concludes by a discussion of possible systematic error influences and improvements

    Using growing RBF-nets in rubber industry process control

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    This paper describes the use of a Radial Basis Function (RBF) neural network in the approximation of process parameters for the extrusion of a rubber profile in tyre production. After introducing the rubber industry problem, the RBF network model and the RBF net learning algorithm are developed, which uses a growing number of RBF units to compensate the approximation error up to the desired error limit. Its performance is shown for simple analytic examples. Then the paper describes the modelling of the industrial problem. Simulations show good results, even when using only a few training samples. The paper is concluded by a discussion of possible systematic error influences, improvements and potential generalisation benefits. Keywords: Adaptive process control; Parameter estimation; RBF-nets; Rubber extrusio

    Adaptive process control in rubber industry

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    This paper describes the problems and an adaptive solution for process control in rubber industry. We show that the human and economical benefits of an adaptive solution for the approximation of process parameters are very attractive. The modeling of the industrial problem is done by the means of artificial neural networks. For the example of the extrusion of a rubber profile in tire production our method shows good results even using only a few training samples

    Symbiosis through exploitation and the merger of lineages in evolution

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    A model for the coevolution of two species in facultative symbiosis is used to investigate conditions under which species merge to form a single reproductive unit. Two traits evolve in each species, the first affecting loss of resources from an individual to its partner, and the second affecting vertical transmission of the symbiosis from one generation to the next. Initial conditions are set so that the symbiosis involves exploitation of one partner by the other and vertical transmission is very rare. It is shown that, even in the face of continuing exploitation, a stable symbiotic unit can evolve with maximum vertical transmission of the partners. Such evolution requires that eventually deaths should exceed births for both species in the free-living state, a condition which can be met if the victim, in the course of developing its defences, builds up sufficiently large costs in the free-living state. This result expands the set of initial conditions from which separate lineages can be expected to merge into symbiotic units

    Nuclear forces from chiral Lagrangians using the method of unitary transformation II: The two-nucleon system

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    We employ the chiral nucleon-nucleon potential derived in ref.[1] to study bound and scattering states in the two-nucleon system. At next-to-leading order, this potential is the sum of renormalized one-pion and two-pion exchange and contact interactions. At next-to-next-to-leading order, we have additional chiral two-pion exchange with low-energy constants determined from pion-nucleon scattering. Alternatively, we consider the \Delta(1232) as an explicit degree of freedom in the effective field theory. The nine parameters related to the contact interactions can be determined by a fit to the np S- and P-waves and the mixing parameter \epsilon_1 for laboratory energies below 100 MeV. The predicted phase shifts and mixing parameters for higher energies and higher angular momenta are mostly well described for energies below 300 MeV. The S-waves are described as precisely as in modern phenomenological potentials. We find a good description of the deuteron properties.Comment: 41 pp, LaTeX2e file, 16 figures (uses epsf

    On relating multiple M2 and D2-branes

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    Due to the difficulties of finding superconformal Lagrangian theories for multiple M2-branes, we will in this paper instead focus on the field equations. By relaxing the requirement of a Lagrangian formulation we can explore the possibility of having structure constants fABCDf^{ABC}{}_D satisfying the fundamental identity but which are not totally antisymmetric. We exemplify this discussion by making use of an explicit choice of a non-antisymmetric fABCDf^{ABC}{}_D constructed from the Lie algebra structure constants fabcf^{ab}{}_c of an arbitrary gauge group. Although this choice of fABCDf^{ABC}{}_D does not admit an obvious Lagrangian description, it does reproduce the correct SYM theory for a stack of NN D2-branes to leading order in gYM1g_{YM}^{-1} upon reduction and, moreover, it sheds new light on the centre of mass coordinates for multiple M2-branes.Comment: 9 pages, references added and statements concerning the fundamental identity revise

    Off-shell structure of twisted (2,0) theory

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    A QQ-exact off-shell action is constructed for twisted abelian (2,0) theory on a Lorentzian six-manifold of the form M1,5=C×M4M_{1,5} = C\times M_4, where CC is a flat two-manifold and M4M_4 is a general Euclidean four-manifold. The properties of this formulation, which is obtained by introducing two auxiliary fields, can be summarised by a commutative diagram where the Lagrangian and its stress-tensor arise from the QQ-variation of two fermionic quantities VV and λμν\lambda^{\mu\nu}. This completes and extends the analysis in [arXiv:1311.3300].Comment: 15 pages, 2 figure

    Ab initio lattice results for Fermi polarons in two dimensions

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    We investigate the attractive Fermi polaron problem in two dimensions using non-perturbative Monte Carlo simulations. We introduce a new Monte Carlo algorithm called the impurity lattice Monte Carlo method. This algorithm samples the path integral in a computationally efficient manner and has only small sign oscillations for systems with a single impurity. As a benchmark of the method, we calculate the universal polaron energy in three dimensions in the scale-invariant unitarity limit and find agreement with published results. We then present the first fully non-perturbative calculations of the polaron energy in two dimensions and density correlations between the impurity and majority particles in the limit of zero range interactions. We find evidence for a smooth crossover transition from fermionic quasiparticle to molecular state as a function of interaction strength.Comment: Includes new results on density-density correlations. Final version as will appear in Phys. Rev. Let
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