5,105 research outputs found

    Stabilization Control of the Differential Mobile Robot Using Lyapunov Function and Extended Kalman Filter

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    This paper presents the design of a control model to navigate the differential mobile robot to reach the desired destination from an arbitrary initial pose. The designed model is divided into two stages: the state estimation and the stabilization control. In the state estimation, an extended Kalman filter is employed to optimally combine the information from the system dynamics and measurements. Two Lyapunov functions are constructed that allow a hybrid feedback control law to execute the robot movements. The asymptotical stability and robustness of the closed loop system are assured. Simulations and experiments are carried out to validate the effectiveness and applicability of the proposed approach.Comment: arXiv admin note: text overlap with arXiv:1611.07112, arXiv:1611.0711

    Renormalization group-like proof of the universality of the Tutte polynomial for matroids

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    In this paper we give a new proof of the universality of the Tutte polynomial for matroids. This proof uses appropriate characters of Hopf algebra of matroids, algebra introduced by Schmitt (1994). We show that these Hopf algebra characters are solutions of some differential equations which are of the same type as the differential equations used to describe the renormalization group flow in quantum field theory. This approach allows us to also prove, in a different way, a matroid Tutte polynomial convolution formula published by Kook, Reiner and Stanton (1999). This FPSAC contribution is an extended abstract.Comment: 12 pages, 3 figures, conference proceedings, 25th International Conference on Formal Power Series and Algebraic Combinatorics, Paris, France, June 201

    Energy harvesting over Rician fading channel: A performance analysis for half-duplex bidirectional sensor networks under hardware impairments

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    In this paper, a rigorous analysis of the performance of time-switching energy harvesting strategy that is applied for a half-duplex bidirectional wireless sensor network with intermediate relay over a Rician fading channel is presented to provide the exact-form expressions of the outage probability, achievable throughput and the symbol-error-rate (SER) of the system under the hardware impairment condition. Using the proposed probabilistic models for wireless channels between mobile nodes as well as for the hardware noises, we derive the outage probability of the system, and then the throughput and SER can be obtained as a result. Both exact analysis and asymptotic analysis at high signal-power-to-noise-ratio regime are provided. Monte Carlo simulation is also conducted to verify the analysis. This work confirms the effectiveness of energy harvesting applied in wireless sensor networks over a Rician fading channel, and can provide an insightful understanding about the effect of various parameters on the system performance.Web of Science186art. no. 1781

    Ultrasoft NLL Running of the Nonrelativistic O(v) QCD Quark Potential

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    Using the nonrelativistic effective field theory vNRQCD, we determine the contribution to the next-to-leading logarithmic (NLL) running of the effective quark-antiquark potential at order v (1/mk) from diagrams with one potential and two ultrasoft loops, v being the velocity of the quarks in the c.m. frame. The results are numerically important and complete the description of ultrasoft next-to-next-to-leading logarithmic (NNLL) order effects in heavy quark pair production and annihilation close to threshold.Comment: 25 pages, 7 figures, 3 tables; minor modifications, typos corrected, references added, footnote adde

    Two-way half duplex decode and forward relaying network with hardware impairment over Rician fading channel: system performance analysis

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    In this paper, the system performance analysis of a two-way decode and forward (DF) relaying network over the Rician fading environment under hardware impairment effect is proposed, analyzed and demonstrated. In this analysis, the analytical mathematical expressions of the achievable throughput, the outage probability, and ergodic capacity were proposed, analyzed and demonstrated. After that, the effect of various system parameters on the system performance is deeply studied with closed-form expressions for the system performance. Finally, the analytical results are also demonstrated by Monte-Carlo simulation in comparison with the closed-form expressions. The numerical results demonstrated and convinced the effect of the system parameters on the system performance of the two-way DF relaying network. The results show that the analytical mathematical and simulated results match for all possible parameter values.Web of Science242787

    Percutaneous pulmonary valve implantation alters electrophysiologic substrate

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    BACKGROUND: Percutaneous pulmonary valve implantation (PPVI) is first‐line therapy for some congenital heart disease patients with right ventricular outflow tract dysfunction. The hemodynamics improvements after PPVI are well documented, but little is known about its effects on the electrophysiologic substrate. The objective of this study is to assess the short‐ and medium‐term electrophysiologic substrate changes and elucidate postprocedure arrhythmias. METHODS AND RESULTS: A retrospective chart review of patients undergoing PPVI from May 2010 to April 2015 was performed. A total of 106 patients underwent PPVI; most commonly these patients had tetralogy of Fallot (n=59, 55%) and pulmonary insufficiency (n=60, 57%). The median follow‐up time was 28 months (7‐63 months). Pre‐PPVI, 25 patients (24%) had documented arrhythmias: nonsustained ventricular tachycardia (NSVT) (n=9, 8%), frequent premature ventricular contractions (PVCs) (n=6, 6%), and atrial fibrillation/flutter (AF/AFL) (n=10, 9%). Post‐PPVI, arrhythmias resolved in 4 patients who had NSVT (44%) and 5 patients who had PVCs (83%). New arrhythmias were seen in 16 patients (15%): 7 NSVT, 8 PVCs, and 1 AF/AFL. There was resolution at medium‐term follow‐up in 6 (86%) patients with new‐onset NSVT and 7 (88%) patients with new‐onset PVCs. There was no difference in QRS duration pre‐PPVI, post‐PPVI, and at medium‐term follow‐up (P=0.6). The median corrected QT lengthened immediately post‐PPVI but shortened significantly at midterm follow‐up (P<0.01). CONCLUSIONS: PPVI reduced the prevalence of NSVT. The majority of postimplant arrhythmias resolve by 6 months of follow‐up

    Improved Perturbative QCD Approach to the Bottomonium Spectrum

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    Recently it has been shown that the gross structure of the bottomonium spectrum is reproduced reasonably well within the non-relativistic boundstate theory based on perturbative QCD. In that calculation, however, the fine splittings and the S-P level splittings are predicted to be considerably narrower than the corresponding experimental values. We investigate the bottomonium spectrum within a specific framework based on perturbative QCD, which incorporates all the corrections up to O(alpha_S^5 m_b) and O(alpha_S^4 m_b), respectively, in the computations of the fine splittings and the S-P splittings. We find that the agreement with the experimental data for the fine splittings improves drastically due to an enhancement of the wave functions close to the origin as compared to the Coulomb wave functions. The agreement of the S-P splittings with the experimental data also becomes better. We find that natural scales of the fine splittings and the S-P splittings are larger than those of the boundstates themselves. On the other hand, the predictions of the level spacings between consecutive principal quantum numbers depend rather strongly on the scale mu of the operator \propto C_A/(m_b r^2). The agreement of the whole spectrum with the experimental data is much better than the previous predictions when mu \simeq 3-4 GeV for alpha_S(M_Z)=0.1181. There seems to be a phenomenological preference for some suppression mechanism for the above operator.Comment: 26 pages, 16 figures. Minor changes, to be published in PR

    Running of the heavy quark production current and 1/k potential in QCD

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    The 1/k contribution to the heavy quark potential is first generated at one loop order in QCD. We compute the two loop anomalous dimension for this potential, and find that the renormalization group running is significant. The next-to-leading-log coefficient for the heavy quark production current near threshold is determined. The velocity renormalization group result includes the alpha_s^3 ln^2(alpha_s) ``non-renormalization group logarithms'' of Kniehl and Penin.Comment: 30 pages, journal versio

    1S and MSbar Bottom Quark Masses from Upsilon Sum Rules

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    The bottom quark 1S mass, Mb1SM_b^{1S}, is determined using sum rules which relate the masses and the electronic decay widths of the Υ\Upsilon mesons to moments of the vacuum polarization function. The 1S mass is defined as half the perturbative mass of a fictitious 3S1{}^3S_1 bottom-antibottom quark bound state, and is free of the ambiguity of order ΛQCD\Lambda_{QCD} which plagues the pole mass definition. Compared to an earlier analysis by the same author, which had been carried out in the pole mass scheme, the 1S mass scheme leads to a much better behaved perturbative series of the moments, smaller uncertainties in the mass extraction and to a reduced correlation of the mass and the strong coupling. We arrive at Mb1S=4.71±0.03M_b^{1S}=4.71\pm 0.03 GeV taking αs(MZ)=0.118±0.004\alpha_s(M_Z)=0.118\pm 0.004 as an input. From that we determine the MSˉ\bar{MS} mass as mˉb(mˉb)=4.20±0.06\bar m_b(\bar m_b) = 4.20 \pm 0.06 GeV. The error in mˉb(mˉb)\bar m_b(\bar m_b) can be reduced if the three-loop corrections to the relation of pole and MSˉ\bar{MS} mass are known and if the error in the strong coupling is decreased.Comment: 20 pages, latex; numbers in Tabs. 2,3,4 corrected, a reference and a comment on the fitting procedure added, typos in Eqs. 2 and 23 eliminate
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