Master-slave Scheme Research Articles

Global Uniform Synchronization With Estimated Error Under Transmission Channel Noise

This paper investigates the problem of estimating synchronization errors and its application to global uniform synchronization with an estimated error bound for the master-slave chaos synchronization scheme via linear control input, which is possibly subject to disturbances by unknown but bounded channel noise and time-delay. Based on Lyapunov function, Razumikhin technique, nonlinear parametric variation, and input-to-state stability (ISS) theory, estimation formulas of synchronization errors with or without time-delays but with noise in transmission channel (TC) are derived. By using the error estimation formula, the maximal upper bound for time-delays is also obtained. These formulas can be used to design a control gain matrix which forces the synchronization error to the minimal value. Meanwhile, theoretical discussion is made by comparing Lyapunov-Krasovskii function method with respect to time-delays in TC. After the theoretical analysis, some representative examples and their numerical simulations are given for illustration.

Immersed particle method for fluid–structure interaction

AbstractA method for treating fluid–structure interaction of fracturing structures under impulsive loads is described. The coupling method is simple and does not require any modifications when the structure fails and allows fluid to flow through openings between crack surfaces. Both the fluid and the structure are treated by meshfree methods. For the structure, a Kirchhoff–Love shell theory is adopted and the cracks are treated by introducing either discrete (cracking particle method) or continuous (partition of unity‐based method) discontinuities into the approximation. Coupling is realized by a master–slave scheme where the structure is slave to the fluid. The method is aimed at problems with high‐pressure and low‐velocity fluids, and is illustrated by the simulation of three problems involving fracturing cylindrical shells coupled with fluids. Copyright © 2009 John Wiley & Sons, Ltd.

A NEW CNN-BASED CHAOTIC CIRCUIT: EXPERIMENTAL RESULTS

In this note the dissipative form of the nonlinear oscillator proposed in [Pokrovskii et al., 2007] is introduced. The behavior of such system is investigated through an experimental implementation of the circuit realized using electronic devices. The proposed implementation of the dissipative nonlinear oscillator, based on Cellular Nonlinear Networks, is fully described and the characterization of the rich dynamical behavior of the circuit performed, disclosing the wide range of dynamical behaviors assumed with respect to different values of the forcing frequency. Moreover, a master–slave scheme has been proposed to synchronize two dissipative oscillators in the chaotic regime. The onset of synchronization is proved both theoretically and experimentally.

Experimental robust synchronization of hyperchaotic circuits

Even if complete synchronization between two chaotic circuits can be reached only when the systems are identical, in this paper we address the robustness of synchronization in the presence of parameter mismatches between the coupled circuits in the case of hyperchaotic behavior. In particular, a master–slave scheme based on negative feedback [T. Kapitaniak, Synchronization of chaos using continuous control, Phys. Rev. E 50 (1994) 1642–1644] is considered and the strategy to design the slave system as an observer of the master is given. With the proposed approach, based on the concept of the Master Stability Function, the two circuits are coupled through a unique scalar signal. Experimental results obtained from two hyperchaotic circuits will be presented in order to show that synchronization occurs widely in the range of electronic component tolerances.

SYNCHRONIZATION OF TWO NON-IDENTICAL HYPERCHAOTIC CIRCUITS

In this work we study synchronization in presence of parameter mismatches between two coupled hyperchaotic circuits. A master-slave scheme based on negative feedback [Kapitaniak et al. (1994)] is considered, where the slave system is designed as an observer of the master. The choice of the observer gains is based on the Master Stability Function in the case that the two circuits are coupled through a unique scalar signal. The approach is experimentally validated, showing how synchronization widely occurs in the range of electronic component tolerances.

GLOBAL CHAOS SYNCHRONIZATION OF NONAUTONOMOUS GYROSTAT SYSTEMS VIA VARIABLE SUBSTITUTION CONTROL

This paper suggests a master-slave nonautonomous synchronization scheme with variable substitution control. According to the scheme, some sufficient algebraic criteria for global chaos synchronization of the master and slave nonautonomous gyrostat systems via various single-variable coupling are derived. The effectiveness of the obtained criteria is numerically verified by some examples.

Multi-synchronization of chaos via linear output feedback strategy

Multi-synchronization of chaotic systems based on the master-slave scheme as an extension of the dual synchronization problem is introduced. It is assumed that the only information available from the master systems is a linear combination of their state vectors. The design procedure for multi-synchronization through output feedback strategy is described and the sufficient condition is given. The performance of the proposed algorithm is numerically examined by applying it to the Chen–Lorenz–Rossler and the Duffing–Van der Pol chaotic systems. Simulation results show the effectiveness of the proposed scheme.

Parallelization strategies for rapid and robust evolutionary multiobjective optimization in water resources applications

This study uses a formal metrics-based framework to demonstrate the Master–Slave (MS) and the Multiple-Population (MP) parallelization schemes for the Epsilon-Nondominated Sorted Genetic Algorithm-II ( ε-NSGAII). The MS and MP versions of the ε-NSGAII generalize the algorithm’s auto-adaptive population sizing, ε-dominance archiving, and time continuation to a distributed processor environment using the Message Passing Interface. This study uses three test cases to compare the MS and MP versions of the ε-NSGAII: (1) an extremely difficult benchmark test function termed DTLZ6 drawn from the computer science literature, (2) an unconstrained, continuous hydrologic model calibration test case for the Leaf River near Collins, Mississippi, and (3) a discrete, constrained four-objective long-term groundwater monitoring (LTM) application. The MP version of the ε-NSGAII is more effective than the MS scheme when solving DTLZ6. Both the Leaf River and the LTM test cases proved to be more appropriately suited to the MS version of the ε-NSGAII. Overall, the MS version of the ε-NSGAII exhibits superior performance on both of the water resources applications, especially when considering its simplicity and ease-of-implementation relative to the MP scheme. A key conclusion of this study is that a simple MS parallelization strategy can exploit time-continuation and parallel speedups to dramatically improve the efficiency and reliability of evolutionary multiobjective algorithms in water resources applications.

速度制御系をベースとしたマスタースレーブ方式による射出装置の同軸制御

In this paper, a novel master-slave system is proposed for the coaxial control of injection equipments constituted with two or more drive axes. Each drive axis is basically controlled by the PI speed control system and a new master-slave scheme is introduced for the tracking control of the angles of the two parallel subsystems. The adequacy of the scheme is supported by the controllability of the system. Easiness of the parameter tuning of the controller is clarified from the viewpoint of stability, tracking property, and disturbance rejection property. Simulation result and experimental result are also given for the test equipment.

Schemes for Indoor Network Synchronization in UWB Positioning

Location Positioning is a major technology for ubiquitous computing. A research on Location Positioning using UWB is ongoing. In order to construct an indoor location network, synchronization of base stations is very important. NTP is popularly used as a clock synchronization protocol ranging from LAN to WAN. The Master-Slave scheme, however, is the simplest method for synchronizing an indoor network that uses UWB. In this paper, we compare and analyze the NTP and Master-Slave schemes according to the statistical channel model for an indoor multi-path propagation environment. Error ranges are calculated at various circumstances such as when the indoor network expands from one primary base station to several base stations. In particular, we compare the correctness of the NTP and Master-Slave synchronization methods. We have found that NTP is a more reasonable synchronization protocol in UWB positioning.

Synchronizing Tracking Control for Flexible Joint Robots via Estimated State Feedback

In this paper, we propose a synchronization controller for flexible joint robots, which are interconnected in a master-slave scheme. The synchronization controller is based on feedback linearization and only requires measurements of the master and slave link positions, since the velocities and accelerations are estimated by means of model-based nonlinear observers. It is shown, using Lyapunov function based stability analysis, that the proposed synchronization controller yields local uniformly ultimately boundedness of the closed loop errors. A tuning gain procedure is presented. The results are supported by simulations in a one degree of freedom master-slave system.

High-frequency broad-band signal generation using a semiconductor laser with a chaotic optical injection

Chaotic signals with a flat power spectrum over 20 GHz have been generated using two commercially available semiconductor lasers coupled in a unidirectional master-slave scheme. The master laser has an external optical feedback that induces optical chaos in the laser output. A part of the chaotic light output from the master laser is injected into the slave laser. We experimentally demonstrated the generation of broad-band signals up to 22 GHz using lasers whose relaxation oscillation frequency in the free-running state is only around 6.4 GHz. We also show that the experimental results can be well reproduced by numerical simulations using two coupled rate equations. The numerical investigation shows that the high-frequency broad-band signal generation is owing to two key effects: high-frequency oscillations as a result of beating between the master and slave laser lights, and spectrum flattening due to the injection of the chaotic signal. The flatness, stability, and tunability of the power spectra demonstrated in our experiments suggests that the proposed system can be potentially useful for generation of high-frequency broad-band random signals.

Parallel Algorithms for Particles–Turbulence Two-Way Interaction Direct Numerical Simulation

Understanding the demixing effect on the dispersion of particles by large-scale turbulence is very important in practical applications. Using pseudo-spectral and Lagrangian approaches, we have simulated a three-dimensional particle-laden mixing layer under one-way coupling effect. However, the computer resource required to simulate such a two-phase flow with high Reynolds number and two-way momentum coupling effect exceeds the limit of the current single processor. In this paper, the computation of particles and the two-way momentum coupling terms are partitioned in the span-wise direction because particles are distributed most evenly in this direction. The computation of the tree-dimensional flow field is first partitioned into three groups of processors because of the most independence of the computation among the three spatial dimensions. In each group, the domain is then partitioned using two different schemes based on the property of the fast Fourier transformation. The first one, the master–slave scheme, is employed for Algorithm MS due to its simplicity and overlapping of communication and computation. The second one, the transpose approach, is used for Algorithm TP order to partition all of the flow field computation. An analysis shows that compared to Algorithm MS, Algorithm TP can also reduce nearly a half of the amount of communication work. Experiments show that Algorithm MS has obtained a speedup of 4.3 using 9HP workstations and a speedup of 6.4 using 15 nodes of IBM SP-2 for a problem size on the order of 643, and Algorithm TP has achieved speedups 44% higher than Algorithm MS.

High-Performance Implementation and Analysis of the Linkmap Program

Linkage analysis uses information from family pedigrees to map genes and locate disease genes on particular chromosomes. A recombination fraction denoted as θ is estimated as a measure of crossing over between two loci. Genetic linkage calculations are very time-consuming particularly for large family pedigrees, a large number of θ values, and an increased number of markers. This paper reports the implementation of a dynamic master-slave scheme for the parallelization of the Linkmap program on a high-performance cluster such as the Origin 2000 (O2K) consisting of 56 R12000 processors. The Linkmap program is one of four programs in the LINKAGE;shFASTLINK legacy package widely used by the medical research community. Implementations issues are addressed and results are compared with previous results on a cluster of DEC Alphas, and with the sequential execution on the O2K machine.

Co-ordination of Two Robot Manipulators via Nonlinear Estimated State Feedback

In this note we present a controller that solves the problem of co-ordination of two (or more) robots, under a master-slave scheme, in the case when only position measurements are available. The controller consists of a feedback control law based on estimated velocities, which are generated by two nonlinear observers (for master and slave robot respectively). It is shown that the controller yields semi-global uniform ultimate boundedness of the closed loop errors, and a relation between this bound and the gains of the controller is established, as well as for the region of attraction.

Coordination of two robot manipulators based on position measurements only

In this note we propose a controller that solves the problem of coordination of two (or more) robots, under a master-slave scheme, in the case when only position measurements are available. The controller consists of a feedback control law, and two non-linear observers. It is shown that the controller yields ultimate uniformly boundedness of the closed loop errors, a relation between this bound and the gains on the controller is established. Simulation results on two twolink robot systems show the predicted convergence performance.

Diode laser frequency-noise suppression by >50 dB by use of electro-optic parametric master oscillators

We demonstrate a novel frequency-stabilization scheme for laser diodes that is capable of linewidth reduction by more than 5 orders of magnitude. In this master-slave scheme the diode laser emission is frequency-offset phase locked to the emission of an electro-optic parametric oscillator (EOPO), and the laser diode is simultaneously used as the EOPO pump source. As a result the initial frequency fluctuations of the pump are reduced to the intrinsic noise level of the EOPO, which can be extremely small. We demonstrate that subhertz linewidths of the beat notes of the signals of two of these systems can be readily achieved if acoustic perturbations are suppressed.

Master-slave scheme and controlling chaos in the Braiman-Goldhirsch method

This Brief Report presents a master-slave scheme to demonstrate explicitly how control chaos works in the Braiman-Goldhirsch method for the one-dimensional map system. The scheme also naturally explains why the anomalous responses arise in a periodically perturbed, unimodal map system. The extension of the master-slave scheme to the D-dimensional map is also presented.

Magneto-optic trapping of lithium using semiconductor lasers

We present an experimental investigation of a magneto-optical trap for 7 Li atoms which is operated exclusively with low-power single-mode diode lasers. A master-slave scheme based on injection locking of two diode lasers is employed to reach sufficiently high power of tunable narrowband radiation. The trap is loaded from an atomic beam which is decelerated in a compact Zeeman-slower with decreasing field resulting in trap loading rates close to 10 8 atoms/s. The dependence of loading rate, trap spring constant, temperature, number and density of trapped atoms on the laser parameters is studied. More than 10 9 atoms are accumulated at a density approaching 10 11 atoms/cm 3. Since the highest particle numbers are achieved at trap laser detunings of several linewidths from resonance, light-assisted inelastic collisions are of minor importance, and the number of trapped atoms is mainly limited by background gas collisions. The volume occupied by the trapped atoms is found to be independent of the particle number for densities up to 10 10 atoms/cm 3 and particle numbers up to 10 8. The lowest measured temperature 300±50 μK corresponds to a momentum spread of 7 photon recoil momenta.

Design and implementation of a tunable 40 MHz-70 MHz Gm-C bandpass ΔΣ modulator

The discrete-time /spl Delta//spl Sigma/ modulator is transformed to the continuous-time /spl Delta//spl Sigma/ modulator. For either nonreturn to-zero or return to-zero feedback, the loop transfer functions of the continuous-time and discrete-time modulators can be made exactly equivalent. Hence, a stable discrete-time /spl Delta//spl Sigma/ modulator is mapped to a stable continuous-time /spl Delta//spl Sigma/ modulator having the same SNR. The anti-alias (image rejection) properties of the continuous-time modulator are described. Experimental results for a tunable 40 MHz-70 MHz continuous-time Gm-C modulator are shown to verify the theory. A master-slave tuning scheme is developed to tune the Gm-C /spl Delta//spl Sigma/ loop filter.