PERFORMANCE ANALYSIS OF AN INPUT-BUFFERED ATM SWITCHING FABRIC WITH INDEPENDENT WINDOW-ACCESS SCHEME

In this paper, an Independent Window-Access(IWA) scheme is proposed, and the performance of an input-buffered ATM switching fabric with the IWA scheme is analysed by means of a probability generating function approach, the closed formulas of the average cell delay and the maximum throughput are given, and results show that the IWA scheme makes the switching fabric have better performances than traditional window-access scheme. The computer simulation results are in good agreement with these analytical results.

Discontinuous event-trigger scheme for global stabilization of state-dependent switching neural networks with communication delay

This paper is concerned with the global stabilization of state-dependent switching neural networks(SDSNNs)viadiscontinuous event-triggered control with network-induced communication delay.Aiming at decreasing triggering times,a discontinuous event-trigger scheme is utilized to determine whether the sampling information is required to be sent outor not.Meanwhile,under the effect of communication delay,the trigger condition and SDSNNs are transformed into twotractable models by designing a fictitious delay function.Then,using the Lyapunov–Krasovskii stability theory,someinequality estimation techniques,and extended reciprocally convex combination method,two sufficient criteria are established for ensuring the global stabilization of the resulting closed-loop SDSNNs,respectively.A unified framework isderived that has the ability to handle the simultaneous existence of the communication delay,the properties of discontinuousevent-trigger scheme,as well as feedback controller design.Additionally,the developed results demonstrate a quantitativerelationship among the event trigger parameter,communication delay,and triggering times.Finally,two numerical examples are presented to illustrate the usefulness of the developed stabilization scheme.

UNITED STABILIZING SCHEME FOR EDGE DELAY IN OPTICAL BURST SWITCHED NETWORKS

A novel scheme, namely united stabilizing scheme for edge delay, is introduced in optical burst switched networks. In the scheme, the limits of burst length and assembly time are both set according to certain qualifications. For executing the scheme, the conception for unit input bit rate is introduced to improve universality, and the assembly algorithm with a buffer safety space under the self-similar traffic model at each ingress edge router is proposed. Then, the components of burst and packet delay are concluded, and the equations that limits of burst length and assembly time should satisfy to stabilize the burst edge delay under different buffer offered loads are educed. The simulation results show that united stabilizing scheme stabilizes both burst and packet edge delay to a great extent when buffer offered load changes from 0.1 to 1, and the edge delay of burst and packet are near the limit values under larger offered load, respectively.

基于通道交换(Path Switching)的ATM交换

首次将虚通道概念引入到ＡＴＭ交换技术中，提出一种基于通道交换的ＡＴＭ交换，基交换结构采用模块化设计思想和分布式控制原理。准静态（周期的或固定的）路由策略，可确保所建立的线条虚通道的有效带宽。与信元交换和电路交换比较表明：通道交换有更优越的性能，更适于组建大规模ＡＴＭ交换结构。同时，在交换技术中引入虚通道概念，为开发ＡＴＭ交换技术提供了新思路。

Switching Equalization Algorithm Based on a New SNR Estimation Method

It is well-known that turbo equalization with the max-log-map （MLM） rather than the log-map （LM） algorithm is insensitive to signal to noise ratio （SNR） mismatch. As our first contribution, an improved MLM algorithm called scaled max-log-map （SMLM） algorithm is presented. Simulation results show that the SMLM scheme can dramatically outperform the MLM without sacrificing the robustness against SNR mismatch. Unfortunately, its performance is still inferior to that of the LM algorithm with exact SNR knowledge over the class of high-loss channels. As our second contribution, a switching turbo equalization scheme, which switches between the SMLM and LM schemes, is proposed to practically close the performance gap. It is based on a novel way to estimate the SNR from the reliability values of the extrinsic information of the SMLM algorithm.

Event-triggered H_(∞) PI state estimation for delayed switched neural networks

On state estimation problems of switched neural networks,most existing results with an event-triggered scheme(ETS)not only ignore the estimator information,but also just employ a fixed triggering threshold,and the estimation error cannot be guaranteed to converge to zero.In addition,the state estimator of non-switched neural networks with integral and exponentially convergent terms cannot be used to improve the estimation performance of switched neural networks due to the difficulties caused by the nonsmoothness of the considered Lyapunov function at the switching instants.In this paper,we aim at overcoming such difficulties and filling in the gaps,by proposing a novel adaptive ETS(AETS)to design an event-based H_(∞)switched proportional-integral(PI)state estimator.A triggering-dependent exponential convergence term and an integral term are introduced into the switched PI state estimator.The relationship among the average dwell time,the AETS and the PI state estimator are established by the triggering-dependent exponential convergence term such that estimation error asymptotically converges to zero with H_(∞)performance level.It is shown that the convergence rate of the resultant error system can be adaptively adjusted according to triggering signals.Finally,the validity of the proposed theoretical results is verified through two illustrative examples.

Iterative Learning Control for a Class of Linear Continuous-time Switched Systems with Fixed Initial Shifts

This paper deals with the problem of iterative learning control for a class of linear continuous-time switched systems in the presence of a fixed initial shift. Here, the considered switched systems are operated during a finite time interval repetitively. According to the characteristics of the systems, a PD-type learning scheme is proposed for such switched systems with arbitrary switching rules, and the corresponding output limiting trajectories under the action of the PD-type learning scheme are given. Based on the contraction mapping method, it is shown that this scheme can guarantee the outputs of the systems converge uniformly to the output limiting trajectories of the systems over the whole time interval. Furthermore, the initial rectifying strategies are applied to the systems for eliminating the effect of the fixed initial shift. When the learning scheme is applied to the systems, the outputs of the systems can converge to the desired reference trajectories over a pre-specified interval. Finally, simulation examples illustrate the effectiveness of the proposed method.

Self-adjusting entropy-stable scheme for compressible Euler equations

In this work,a self-adjusting entropy-stable scheme is proposed for solving compressible Euler equations.The entropy-stable scheme is constructed by combining the entropy conservative flux with a suitable diffusion operator.The entropy has to be preserved in smooth solutions and be dissipated at shocks.To achieve this,a switch function,which is based on entropy variables,is employed to make the numerical diffusion term be automatically added around discontinuities.The resulting scheme is still entropy-stable.A number of numerical experiments illustrating the robustness and accuracy of the scheme are presented.From these numerical results,we observe a remarkable gain in accuracy.

Fifth-Order A-WENO Schemes Based on the Adaptive Diffusion Central-Upwind Rankine-Hugoniot Fluxes

We construct new fifth-order alternative WENO(A-WENO)schemes for the Euler equations of gas dynamics.The new scheme is based on a new adaptive diffusion centralupwind Rankine-Hugoniot(CURH)numerical flux.The CURH numerical fluxes have been recently proposed in[Garg et al.J Comput Phys 428,2021]in the context of secondorder semi-discrete finite-volume methods.The proposed adaptive diffusion CURH flux contains a smaller amount of numerical dissipation compared with the adaptive diffusion central numerical flux,which was also developed with the help of the discrete RankineHugoniot conditions and used in the fifth-order A-WENO scheme recently introduced in[Wang et al.SIAM J Sci Comput 42,2020].As in that work,we here use the fifth-order characteristic-wise WENO-Z interpolations to evaluate the fifth-order point values required by the numerical fluxes.The resulting one-and two-dimensional schemes are tested on a number of numerical examples,which clearly demonstrate that the new schemes outperform the existing fifth-order A-WENO schemes without compromising the robustness.

Event-Triggered Finite-Time <i>H</i>_∞Control for Switched Stochastic Systems

This paper investigates the problem of event-triggered finite-time H∞ control for a class of switched stochastic systems. The main objective of this study is to design an event-triggered state feedback H∞ controller such that the resulting closed-loop system is finite-time bounded and satisfies a prescribed H∞ level in some given finite-time interval. Based on stochastic differential equations theory and average dwell time approach, sufficient conditions are derived to ensure the finite-time stochastic stability with the prescribed H∞ performance for the relevant closed-loop system by employing the linear matrix inequality technique. Finally, the desired state feedback H∞ controller gain matrices can be expressed in an explicit form.

基于切换策略的车辆质心侧偏角高性能获取

现有的基于融合策略的车辆质心侧偏角(vehicle sideslip angle,VSA)获取方法需要针对不同的场景、结构或信号进行优化和改进,计算复杂度和系统成本也随之增加。本文提出一种基于切换策略的VSA软测量方法。在传感器量测信号预处理部分,利用贝塞尔滤波器对侧向加速度信号进行时延处理和噪声滤除,设计可靠性检验模块对横摆角速度等信号中的突变实现有效清除。在此基础上,根据现有运动学和动力学方案的优势确定切换策略,尽量缩短运动学方案的连续工作区间以抑制其误差累积,同时将动力学方案限制在线性区工作以避免其性能下降,并在多个工况下进行仿真和硬件在环试验,以验证所提出的VSA获取方法的效果。试验结果表明,相较于采用典型的融合策略的对比方法,本文提出的方法在精度和运行时间方面都具有明显的优势,且二者对路况的变化均具有较强的鲁棒性。

A 10 bit 50 MS/s SAR ADC with partial split capacitor switching scheme in 0.18μm CMOS

This paper presents a 10 bit successive approximation register （SAR） analog-to-digital converter （ADC） in 0.18 μm 1P6M CMOS technology with a 1.8 V supply voltage. To improve the conversion speed, a partial split capacitor switching scheme is proposed. By reducing the time constant of the bit cycles, the proposed technique shortens the settling time of a capacitive digital-to-analog converter （DAC）. In addition, a new SAR control logic is proposed to reduce loop delay to further enhance the conversion speed. At 1.8 V supply voltage and 50 MS/s the SAR ADC achieves a signal-to-noise and distortion ratio （SNDR） of 57.5 dB and spurious-free dynamic range （SFDR） of 69.3 dB. The power consumption is 2.26 mW and the core die area is 0.096 mm2.

Conjoint analysis of crowbar switching scheme and its resistancebased on statistical sampling for LVRT of DFIG

An active crowbar protective circuit is an effective and common approach for low voltage ride through(LVRT) of a doubly-fed induction generator(DFIG). The crowbar resistance value and its switching scheme both have crucial effects on safety recovery. The effects encountered are correlative dependence and interplay so that analyzing them from a single factor, as most existing LVRT control methods would do, obtains a partial optimal solution. This paper combines these two factors toanalyze their coordination effects on the LVRT control,and to also investigate whether the global optimal performance of these factors can be achieved. The principles for resistance selection and the schemes for crowbar switching are discussed first. Next, the coupling relationship is ana-lyzed based on statistical sampling simulation data with different resistance values and various switching schemes.The results demonstrate that their coordination has critical influence on rotor peak current, DC-link voltage and reactive power. The optimal coordination will be different according to specific requirements. Hence the global optimal combination could be achieved when all requirements are taken into consideration.

A 12-bit current steering DAC with 2-dimensional gradient-error tolerant switching scheme

A 12-bit intrinsic accuracy digital-to-analog converter integrated into standard digital 0.18μm CMOS technology is proposed. It is based on a current steering segmented 6＋6 architecture and requires no calibration. By dividing one most significant bit unary source into 16 elements located in 16 separated regions of the array, the linear gradient errors and quadratic errors can be averaged and eliminated effectively. A novel static performance testing method is proposed. The measured differential nonlinearity and integral nonlinearity are 0.42 and 0.39 least significant bit, respectively. For 12-bit resolution, the converter reaches an update rate of 100 MS/s. The chip operates from a single 1.8 V voltage supply, and the core die area is 0.28 mm^2.

A congestion alleviated scheme in optical burst switching network

An optical burst switching （OBS） network platform is established with a ring topology of three nodes. A congestion Mleviated scheme using advanced token protocol and wavelength tunable receivers is demon- strated to optimize the network platform. Experimental results testify that this scheme can resist collision at the level of 0.1% congestion rate.

自动扶梯钥匙开关安全隐患分析及其规避方案

近年来为增强自动扶梯的安全性能,研究人员对检验检测技术等开展了卓有成效的研究,但是对于难以发现并具有一定安全隐患的故障现象却没有引起重视。本文以自动扶梯钥匙锁存在的问题为例,对其因长期使用而产生的摩擦磨损、复位弹簧发生形变等问题进行深入剖析,并将其置于控制回路中进行了探讨,最终在自动扶梯钥匙锁的结构、维护保养、使用管理、控制优化方面提出了相应建议,以期规避自动扶梯钥匙锁带来的安全隐患。

An all-optical matrix multiplication scheme with non-linear material based switching system

Optics is a potential candidate in information, data, and image processing. In all-optical data and information processing, optics has been used as information carrying signal because of its inherent advantages of parallelism. Several optical methods are proposed in support of the above processing. In many algebraic, arithmetic, and image processing schemes fundamental logic and memory operations are conducted exploring all-optical devices. In this communication we report an all-optical matrix multiplication operation with non-linear material based switching circuit.

国际会议中心供配电系统设计探讨

以广州白云国际会议中心国际会堂为例,介绍这类对供电可靠性要求很高的会议中心供配电系统的情况和特点。通过案例分析和比较,探讨供配电系统中10kV中低压系统接线方案、移动发电机、UPS等关键电气设备的设置原则和注意事项。

The Theory of Composite and Switching Characteristics under Sampling Scheme-I

Using the new theoretical method managed by theory concerned with recurrent state and transient state obtains complete composite and switching characteristics of various kinds of sampling schemes, especially ISO 2859.