10,768 research outputs found
Variance-constrained multiobjective control and filtering for nonlinear stochastic systems: A survey
The multiobjective control and filtering problems for nonlinear stochastic systems with variance constraints are surveyed. First, the concepts of nonlinear stochastic systems are recalled along with the introduction of some recent advances. Then, the covariance control theory, which serves as a practical method for multi-objective control design as well as a foundation for linear system theory, is reviewed comprehensively. The multiple design requirements frequently applied in engineering practice for the use of evaluating system performances are introduced, including robustness, reliability, and dissipativity. Several design techniques suitable for the multi-objective variance-constrained control and filtering problems for nonlinear stochastic systems are discussed. In particular, as a special case for the multi-objective design problems, the mixed H 2 / H ∞ control and filtering problems are reviewed in great detail. Subsequently, some latest results on the variance-constrained multi-objective control and filtering problems for the nonlinear stochastic systems are summarized. Finally, conclusions are drawn, and several possible future research directions are pointed out
Fuzzy-logic-based control, filtering, and fault detection for networked systems: A Survey
This paper is concerned with the overview of the recent progress in fuzzy-logic-based filtering, control, and fault detection problems. First, the network technologies are introduced, the networked control systems are categorized from the aspects of fieldbuses and industrial Ethernets, the necessity of utilizing the fuzzy logic is justified, and the network-induced phenomena are discussed. Then, the fuzzy logic control strategies are reviewed in great detail. Special attention is given to the thorough examination on the latest results for fuzzy PID control, fuzzy adaptive control, and fuzzy tracking control problems. Furthermore, recent advances
on the fuzzy-logic-based filtering and fault detection problems are reviewed. Finally, conclusions are given and some possible future research directions are pointed out, for example, topics on two-dimensional networked systems, wireless networked control systems, Quality-of-Service (QoS) of networked systems, and fuzzy access control in open networked systems.This work was supported in part by the National Natural Science Foundation of China under Grants 61329301,
61374039, 61473163, and 61374127, the Hujiang Foundation of China under Grants C14002 andD15009, the Engineering and Physical Sciences Research Council (EPSRC) of the UK, the Royal Society of the UK, and the Alexander von Humboldt Foundation of Germany
Structural and electronic properties of the metal-metal intramolecular junctions of single-walled carbon nanotubes
Several intramolecular junctions (IMJs) connecting two metallic (11, 8) and
(9, 6) carbon nanotubes along their common axis have been realized by using a
layer-divided technique to the nanotubes and introducing the topological
defects. Atomic structure of each IMJ configuration is optimized with a
combination of density-functional theory (DFT) and the universal force field
(UFF) method, based upon which a four-orbital tight-binding calculation is made
on its electronic properties. Different topological defect structures and their
distributions on the IMJ interfaces have been found, showing decisive effects
on the localized density of states, while the sigma-pi coupling effect is
negligible near Fermi energy (EF). Finally, a new IMJ model has been proposed,
which probably reflects a real atomic structure of the M-M IMJ observed in the
experiment [Science 291, 97 (2001)].Comment: 11 pages and 3 figure
Scaling of Anisotropic Flows and Nuclear Equation of State in Intermediate Energy Heavy Ion Collisions
Elliptic flow () and hexadecupole flow () of light clusters have
been studied in details for 25 MeV/nucleon Kr + Sn at large
impact parameters by Quantum Molecular Dynamics model with different potential
parameters. Four parameter sets which include soft or hard equation of state
(EOS) with/without symmetry energy term are used. Both number-of-nucleon ()
scaling of the elliptic flow versus transverse momentum () and the scaling
of versus have been demonstrated for the light clusters
in all above calculation conditions. It was also found that the ratio of
keeps a constant of 1/2 which is independent of for all the
light fragments. By comparisons among different combinations of EOS and
symmetry potential term, the results show that the above scaling behaviors are
solid which do not depend the details of potential, while the strength of flows
is sensitive to EOS and symmetry potential term.Comment: 5 pages, 5 figure
Phenomenological Scaling of Rapidity Dependence for Anisotropic Flows in 25 MeV/nucleon Ca + Ca by Quantum Molecular Dynamics Model
Anisotropic flows (, , and ) of light fragments up till
the mass number 4 as a function of rapidity have been studied for 25
MeV/nucleon Ca + Ca at large impact parameters by Quantum
Molecular Dynamics model. A phenomenological scaling behavior of rapidity
dependent flow parameters (n = 1, 2, 3 and 4) has been found as a
function of mass number plus a constant term, which may arise from the
interplay of collective and random motions. In addition, keeps
almost independent of rapidity and remains a rough constant of 1/2 for all
light fragments.Comment: 4 pages, 5 figure
Experimental Long-Distance Decoy-State Quantum Key Distribution Based On Polarization Encoding
We demonstrate the decoy-state quantum key distribution (QKD) with one-way
quantum communication in polarization space over 102km. Further, we simplify
the experimental setup and use only one detector to implement the one-way
decoy-state QKD over 75km, with the advantage to overcome the security
loopholes due to the efficiency mismatch of detectors. Our experimental
implementation can really offer the unconditionally secure final keys. We use 3
different intensities of 0, 0.2 and 0.6 for the pulses of source in our
experiment. In order to eliminate the influences of polarization mode
dispersion in the long-distance single-mode optical fiber, an automatic
polarization compensation system is utilized to implement the active
compensation.Comment: 4 pages,3 figure
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