1,256 publications from this institution
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In the practical thickener cone systems, the underflow concentration is hard to measure through physical sensors while there exist the high cost and significant measurement delay. This paper presents a novel and deeply efficient long short-time memory (DE-LSTM) method for concentration prediction in the deep cone thickener system. First, the DE-LSTM for thicker systems is developed for feature learning and long temporal preprocessing. Then, the feedforward and reverse LSTM subnetworks are employed to learn the robust information without loss. At last, the experimental verification of an industrial deep cone thicker demonstrates the proposed DE-LSTM’s performance outperforms other state-of-the-art methods.
The Designs Travel Award for 2018 has been granted to Mr. David Schmelzeisen, a PhD student from Institut für Textiltechnik (ITA), RWTH Aachen University, Aachen, Germany. [...]
This paper reports on a study undertaken within the CEPT SE42 project team, with the objective of deriving regulatory out-of-block radiation limits for mitigating the impact of adjacent-channel interference between TDD and FDD terminal stations (TSs) in the 2.6 GHz band. We present a novel stochastic approach for the calculation of TS block-edge mask (BEM) out-of-block (or baseline) limits. Appropriate BEM baseline limits are subsequently derived via Monte-Carlo simulations based on interferer TS spatial densities commensurate with those observed in busy hot-spots. It is shown that, for a typical activity factor of up to 12.5%, a TS BEM baseline limit of -22.5 dBm/MHz is sufficient to ensure that the victim TS is desensitized by 3 dB with a probability of only 5%.
European administrations are currently in the process of defining national spectrum sharing frameworks to enable coexistence between new entrant Mobile/Fixed Communication Networks (MFCNs) and the incumbent Fixed Satellite Service (FSS) downlink and Fixed Service (FS) in the 3.6-3.8 GHz band. In this paper we propose a methodology for establishing such frameworks whereby administrations define criteria for the protection of the incumbent users in the form of maximum permitted interference levels at the input of the FSS and FS receivers. These limits are then used to calculate either geographic exclusion zones or the maximum permitted radiated powers of MFCN base stations, so as to avoid harmful interference to the FSS and FS. The above calculations can be performed by the MFCN operators, the administration, or a third party. We also set out a number of novel options to account for interference aggregation and the partitioning of the interference budget across multiple MFCN base stations and operators. There is always a trade-off between the simplicity of a spectrum sharing framework and spectrum sharing efficiency. The proposed methodology provides the flexibility for administrations to exploit this trade-off according to their specific national circumstances.
This paper is concerned with the problem of robust reliable control for a class of uncertain discrete impulsive switched systems with state delays, where the actuators are subjected to failures. The parameter uncertainties are assumed to be norm-bounded, and the average dwell time approach is utilized for the stability analysis and controller design. Firstly, an exponential stability criterion is established in terms of linear matrix inequalities (LMIs). Then, a state feedback controller is constructed for the underlying system such that the resulting closed-loop system is exponentially stable. A numerical example is given to illustrate the effectiveness of the proposed method.
This paper deals with the wavelet-based performance analysis of the safety barrier for use in a full-scale test. The test involves a vehicle, a Ford Fiesta, which strikes the safety barrier at a prescribed angle and speed. The vehicle speed before the collision was measured. Vehicle accelerations in three directions at the centre of gravity were measured during the collision. The yaw rate was measured with a gyro meter. Using normal speed and high-speed video cameras, the behavior of the safety barrier and the test vehicle during the collision was recorded. Based upon the results obtained, the tested safety barrier, has proved to satisfy the requirements for an impact severity level. By taking into account the Haar wavelets, the property of integral operational matrix is utilized to find an algebraic representation form for calculate of wavelet coefficients of acceleration signals. It is shown that Haar wavelets can construct the acceleration signals well.
This paper is concerned with the problem of global finite-time control for switched nonlinear systems whose nonlinear terms satisfy homogenous growth conditions. At first, we design homogenous output feedback controllers for nominal switched nonlinear systems by adding a power integrator method. Then, we employ the homogeneous domination approach to scale homogeneous observers and controllers to render switched nonlinear systems with lower-triangular homogenous growth condition globally finite-time stable. Finally, the proposed control method can be extended to switched nonlinear systems satisfying with upper-triangular homogeneous growth condition. Two examples are provided to demonstrate the effectiveness of the proposed control scheme.
The objective of this chapter is to study the problem of vibration control analysis and synthesis in a vehicle engine-body vibration structure. It is assumed that the actuator is subject to a time-varying delay for control of bounce and pitch vibrations. Based on a Lyapunov-Krasovskii functional and using some free weighting matrices, delay-dependent sufficient conditions for designing desired state- and output-feedback controllers are given in terms of linear matrix inequalities (LMIs). The state- and output-feedback controllers, which guarantee asymptotic stability with a prescribed γ-level L2-gain (or H∞ performance), are then developed directly instead of coupling the second-order model to a first-order system. The controller gains are determined by convex optimization over LMIs. Simulation results are included to demonstrate the validity and applicability of the technique.
No abstract is provided for this article.
The consensus problem has a crucial role in theoretical and practical aspects of interconnected systems, for instance in smart computing field. This paper is concerned with the observer-based H∞ consensus problem for a class of linear multi-agent systems subject to measurement outliers. In the addressed observer-based H∞ consensus problem, measurement outliers can affect the estimation accuracy and thus affect the consensus performance. To assuage the impact of measurement outliers, a control protocol based on an observer containing a saturation function with variable saturation limits is proposed. The purpose of this paper is to find a solution to the addressed H∞ consensus problem for a class of linear multi-agent systems subject to measurement outliers by designing an observer-based control protocol such that multi-agent systems can fulfill the H∞ consensus performance over a finite horizon. With the aid of Lyapunov theory, the sufficient condition is established to guarantee that the consensus error dynamic system satisfies the H∞ consensus performance. Then, the linear matrix inequality (LMI) approach is used to obtain the desired parameters of the observer-based control protocol. Finally, the effectiveness of the proposed control protocol is verified in a simulation environment. Aim: The purpose of this study is to find a solution to the addressed H∞ consensus problem for a class of linear multi-agent systems subject to measurement outliers. Methods: By choosing a suitable Lyapunov function, the sufficient condition is obtained, which can guarantee the consensus error dynamic system satisfying the given H∞ consensus performance. The LMI approach is employed to design the desired controller. With Matlab LMI toolbox, a numerical example was conducted to demonstrate the effectiveness of the proposed observer-based control protocol in the simulation environment. Results: A satisfactory consensus performance can be guaranteed for multi-agent systems subject to measurement outliers under the proposed observer-based control protocol. The constructed saturation function with variable saturation limits can mitigate the effect of measurement outliers by dynamically regulating saturation limits. Compared with the traditional observer-based control protocol, in this paper, the proposed observer-based control protocol shows robustness against measurement outliers. Conclusion: A solution to the addressed multi-agent consensus problem subject to measurement outliers was found by designing an observer-based consensus controller. The obtained results can be extended to sensor networks, neural networks, and nonlinear multi-agent systems.
1 School of Electrical and Electronic Engineering, The University of Adelaide, Adelaide, SA 5005, Australia 2 College of Engineering and Science, Victoria University, Melbourne, VIC 8001, Australia 3 Department of Engineering, Faculty of Technology and Science, University of Agder, 4898 Grimstad, Norway 4 School of Control Science and Engineering, Shandong University, Jinan 250061, China 5 School of Automation, Chongqing University, Chongqing 400044, China
This brief focuses on the sliding mode control (SMC) design for nonlinear stochastic switching systems subject to semi-Markov switching parameters and signal quantization. The aim of this brief is to design an efficient SMC scheme under quantization error effect. To this end, a mode-independent sliding surface is adopted to avoid the potential repetitive jumping effects. Then, based on the weak infinitesimal operator theory, sufficient conditions are given for the corresponding stochastic stability criteria. Furthermore, an appropriate SMC law is proposed to drive the state signals onto the predefined manifold and the effect of quantization error can be effectively attenuated. Finally, a single-link robot arm model is provided to illustrate the effectiveness of the theoretical findings.
One of the common problems of power quality is the occurrence of voltage sags due to different types of balanced and unbalanced short-circuit faults in electrical distribution systems. Dynamic Voltage Restorer (DVR) is the most effective equipment used for voltage recovery in power distribution systems and it injects voltage in series with line voltage for voltage recovery. In this paper, the structure and general components of this equipment are presented. In addition, by applying a control scheme based on Synchronous Reference Frame Theory (SRFT) in its control system, the effective role of this equipment in compensating and maintaining the voltage of a power distribution system under the occurrence of balanced three-phase short-circuit fault and unbalanced single-phase to ground short-circuit fault is investigated and analyzed using Simulink/Matlab software.
