3,677 research outputs found
Stabilization Control of the Differential Mobile Robot Using Lyapunov Function and Extended Kalman Filter
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
Neutron star cooling - a challenge to the nuclear mean field
The two recent density-dependent versions of the finite-range M3Y interaction
(CDM3Y and M3Y-P) have been probed against the bulk properties of
asymmetric nuclear matter (NM) in the nonrelativistic Hartree Fock (HF)
formalism. The same HF study has also been done with the famous Skyrme (SLy4)
and Gogny (D1S and D1N) interactions which were well tested in the nuclear
structure calculations. Our HF results are compared with those given by other
many-body calculations like the Dirac-Brueckner Hartree-Fock approach or
ab-initio variational calculation using free nucleon-nucleon interaction, and
by both the nonrelativistic and relativistic mean-field studies using different
model parameters. Although the two considered density-dependent versions of the
M3Y interaction were proven to be quite realistic in the nuclear structure or
reaction studies, they give two distinct behaviors of the NM symmetry energy at
high densities, like the Asy-soft and Asy-stiff scenarios found earlier with
other mean-field interactions. As a consequence, we obtain two different
behaviors of the proton fraction in the -equilibrium which in turn can
imply two drastically different mechanisms for the neutron star cooling. While
some preference of the Asy-stiff scenario was found based on predictions of the
latest microscopic many-body calculations or empirical NM pressure and isospin
diffusion data deduced from heavy-ion collisions, a consistent mean-field
description of nuclear structure database is more often given by some Asy-soft
type interaction like the Gogny or M3Y-P ones. Such a dilemma poses an
interesting challenge to the modern mean-field approaches.Comment: Version accepted for publication in Phys. Rev.
A cell-based smoothed discrete shear gap method (CS-DSG3) using triangular elements for static and free vibration analyses of shell structures
A new scenario of dynamical heterogeneity in supercooled liquid and glassy states of 2D monatomic system
Via analysis of spatio-temporal arrangements of atoms based on their dynamics in supercooled liquid and glassy states of 2D monatomic system with a double-well Lennard-Jones-Gauss (LJG) interaction potential, we find a new scenario of dynamical heterogeneity. Atoms with the same or very close mobility have a tendency to aggregate into clusters. Number of atoms with high mobility (and size of their clusters) increases with decreasing temperature passing over a maximum before decreasing downto zero. Position of the peak moves toward a lower temperature if mobility of atoms in clusters is lower together with an enhancement of height of the peak. In contrast, number of atoms with very low mobility or solidlike atoms (and size of their clusters) has a tendency to increase with decreasing temperature and then it suddenly increases in the vicinity of glass transition temperature leading to the formation of a glassy state. A sudden increase in the number of strongly correlated solidlike atoms in the vicinity of a glass transition temperature ( ) may be an origin of a drastical increase in viscosity of the glass-forming systems approaching glass transition. The fact, we find that diffusion coefficient decays exponentially with fraction of solidlike atoms exhibiting a sudden decrease in the vicinity of glass transition region
Unsupervised deep learning-based reconfigurable intelligent surface aided broadcasting communications in industrial IoTs
This paper presents a general system framework which lays the foundation for Reconfigurable Intelligent Surface (RIS)-enhanced broadcast communications in Industrial Internet of Things (IIoTs). In our system model, we consider multiple sensor clusters co-existing in a smart factory where the direct links between these clusters and a central base station (BS) is blocked completely. In this context, an RIS is utilized to reflect signals broadcast from BS toward cluster heads (CHs) which act as a representative of clusters, where BS only has access to the statistical distribution of the channel state information (CSI). An analytical upper bound of the total ergodic spectral efficiency and an approximation of outage probability are derived. Based on these analytical results, two algorithms are introduced to control the phase shifts at RIS, which are the Riemannian conjugate gradient (RCG) method and the deep neural network (DNN) method. While the RCG algorithm operates based on the conventional iterative method, the DNN technique relies on unsupervised deep learning. Our numerical results show that the both algorithms achieve satisfactory performance based on only statistical CSI. In addition, compared to the RCG scheme, using deep learning reduces the computational latency by more than 10 times with an almost identical total ergodic spectral efficiency achieved. These numerical results reveal that while using conventional RCG method may provide unsatisfactory latency, DNN technique shows much promise for enabling RIS in ultra reliable and low latency communications (URLLC) in the context of IIoTs
Percutaneous pulmonary valve implantation alters electrophysiologic substrate
BACKGROUND: Percutaneous pulmonary valve implantation (PPVI) is firstâline 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 shortâ and mediumâterm 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. AÂ 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 followâup time was 28Â months (7â63Â months). PreâPPVI, 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%). PostâPPVI, 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 mediumâterm followâup in 6 (86%) patients with newâonset NSVT and 7 (88%) patients with newâonset PVCs. There was no difference in QRS duration preâPPVI, postâPPVI, and at mediumâterm followâup (P=0.6). The median corrected QT lengthened immediately postâPPVI but shortened significantly at midterm followâup (P<0.01). CONCLUSIONS: PPVI reduced the prevalence of NSVT. The majority of postimplant arrhythmias resolve by 6Â months of followâup
ZAC: Efficient Zero-Knowledge Dynamic Universal Accumulator and Application to Zero-Knowledge Elementary Database
Virtual and Soft Pair Corrections to Polarized Muon Decay Spectrum
Radiative corrections to the muon decay spectrum due to soft and virtual
electron--positron pairs are calculated.Comment: 10pp, 2 PS figs, details of calculations are adde
Relativistic dynamical polarizability of hydrogen-like atoms
Using the operator representation of the Dirac Coulomb Green function the analytical method in perturbation theory is employed in obtaining solutions of the Dirac equation for a hydrogen-like atom in a time-dependent electric field. The relativistic dynamical polarizability of hydrogen-like atoms is calculated and analysed
Relativistic dynamical polarizability of hydrogen-like atoms
Using the operator representation of the Dirac Coulomb Green function the
analytical method in perturbation theory is employed in obtaining solutions of
the Dirac equation for a hydrogen-like atom in a time-dependent electric field.
The relativistic dynamical polarizability of hydrogen-like atoms is calculated
and analysed.Comment: 15 pages, 3 figures (not included, but hard copies are available upon
request
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