Hybrid Switching System Research Articles

A two-strain model of infectious disease spread with asymmetric temporary immunity periods and partial cross-immunity.

We introduce a two-strain model with asymmetric temporary immunity periods and partial cross-immunity. We derive explicit conditions for competitive exclusion and coexistence of the strains depending on the strain-specific basic reproduction numbers, temporary immunity periods, and degree of cross-immunity. The results of our bifurcation analysis suggest that, even when two strains share similar basic reproduction numbers and other epidemiological parameters, a disparity in temporary immunity periods and partial or complete cross-immunity can provide a significant competitive advantage. To analyze the dynamics, we introduce a quasi-steady state reduced model which assumes the original strain remains at its endemic steady state. We completely analyze the resulting reduced planar hybrid switching system using linear stability analysis, planar phase-plane analysis, and the Bendixson-Dulac criterion. We validate both the full and reduced models with COVID-19 incidence data, focusing on the Delta (B.1.617.2), Omicron (B.1.1.529), and Kraken (XBB.1.5) variants. These numerical studies suggest that, while early novel strains of COVID-19 had a tendency toward dramatic takeovers and extinction of ancestral strains, more recent strains have the capacity for co-existence.

H∞ Tracking Control of Uncertain Markovian Hybrid Switching Systems: A Fuzzy Switching Dynamic Adaptive Control Approach.

This article investigates the H∞ stochastic tracking control problem for uncertain fuzzy Markovian hybrid switching systems by using a fuzzy switching dynamic adaptive control approach. The long and the short is to construct multiple piecewise stochastic Lyapunov functions which provide an effective tool for designing hybrid switching law and fuzzy switching dynamic adaptive law. A hybrid switching law, including both stochastic switching and deterministic switching, is designed to represent more general switching scenarios, which can improve the H∞ adaptive tracking performance through offering a running time before stochastic switching for the adaptive control strategy to work well. A fuzzy switching dynamic adaptive control technique is developed such that all signals of the tracking error equation are bounded, and the system state trajectory tracks the reference model state trajectory under a disturbance attenuation level as closely as possible. Finally, an application study verifies the effectiveness of the acquired methods.

A gradient algorithm for solution of the optimal control problem for hybrid switching systems

SummaryIn this article, an algorithm is presented for solving the optimal control problem for the general form of a hybrid switching system. The cost function comprises terminal, running and switching costs. The controlled system is an autonomous hybrid switching system with jumps either at some switching times or some time varying switching manifolds. The proposed algorithm is an extension of the first‐order gradient method for the conventional optimal control problem. The algorithm requires a low computational effort. The system's dynamical equations together with a set of algebraic equations are solved at each iteration in order to find the descent direction. The convergence of algorithm is proved and examples are provided to demonstrate the efficiency of the algorithm for different types of hybrid switching system optimal control problems.

A Switching Multiplicative Watermarking Scheme for Detection of Stealthy Cyber-Attacks

This article addresses the detection of stealthy attacks on sensor measurements. Inspired in authentication schemes with weak cryptographic guarantees, we propose a watermarking approach to validate the data and its source. In particular, we propose a multiplicative scheme, where the sensor outputs are watermarked by a bank of filters, then transmitted through the possibly unsecured communication network. The original measurement data are finally reconstructed by a watermark remover. To allow the detection of replay attacks, the watermarking filters are devised as hybrid switching systems, whose parameters are assumed to be unknown to the adversary. Design rules are provided, guaranteeing that the nominal closed-loop performance is not deteriorated by the watermarking scheme and ensuring robust stability with mismatched filter parameters. Moreover, we design a switching protocol with no communication overhead to allow the watermarking filters to synchronously update their parameters. The detectability properties of cyber-attacks are analyzed, and the results are illustrated through numerical examples for replay and data injection attacks.

QoS provisioning and energy saving scheme for distributed cognitive radio networks using deep learning

One of the major challenges facing the realization of cognitive radios (CRs) in future mobile and wireless communications is the issue of high energy consumption. Since future network infrastructure will host real-time services requiring immediate satisfaction, the issue of high energy consumption will hinder the full realization of CRs. This means that to offer the required quality of service (QoS) in an energy-efficient manner, resource management strategies need to allow for effective trade-offs between QoS provisioning and energy saving. To address this issue, this paper focuses on single base station (BS) management, where resource consumption efficiency is obtained by solving a dynamic resource allocation (RA) problem using bipartite matching. A deep learning (DL) predictive control scheme is used to predict the traffic load for better energy saving using a stacked auto-encoder (SAE). Considered here was a base station (BS) processor with both processor sharing (PS) and first-come-first-served (FCFS) sharing disciplines under quite general assumptions about the arrival and service processes. The workload arrivals are defined by a Markovian arrival process while the service is general. The possible impatience of customers is taken into account in terms of the required delays. In this way, the BS processor is treated as a hybrid switching system that chooses a better packet scheduling scheme between mean slowdown (MS) FCFS and MS PS. The simulation results presented in this paper indicate that the proposed predictive control scheme achieves better energy saving as the traffic load increases, and that the processing of workload using MS PS achieves substantially superior energy saving compared to MS FCFS.

On the Decidability of Membership in Matrix-exponential Semigroups

We consider the decidability of the membership problem for matrix-exponential semigroups: Given k ∈ N and square matrices A 1 , … , A k , C , all of the same dimension and with real algebraic entries, decide whether C is contained in the semigroup generated by the matrix exponentials exp ( A i t ), where i ∈ { 1,… , k } and t ≥ 0. This problem can be seen as a continuous analog of Babai et al.’s and Cai et al.’s problem of solving multiplicative matrix equations and has applications to reachability analysis of linear hybrid automata and switching systems. Our main results are that the semigroup membership problem is undecidable in general, but decidable if we assume that A 1 , … , A k commute. The decidability proof is by reduction to a version of integer programming that has transcendental constants. We give a decision procedure for the latter using Baker’s theorem on linear forms in logarithms of algebraic numbers, among other tools. The undecidability result is shown by reduction from Hilbert’s Tenth Problem.

Study of the effect of adiabatic heating on the operation of the electrodynamic actuator

Electrodynamic actuators are used in hybrid switching systems where a very quick contact separation as well as operation repeatability and long-term reliability are required. The article presents selected results of thermal studies in the electrodynamic drive system. Study was carried out on the ba sis of the 3D electromagneto-thermal model implemented in the Ansys_Maxwell environment. The present model allows to determine the critical parameters related to the heating and to guarantee the correct and repeatable operation of the actuator.

Hybrid adaptive framework for coordinated control of distributed generators in cyber‐physical energy systems

With the development of information and communications technology (ICT) and inundation of sensing devices, the control of smart grid is undergoing a paradigm shift from centralised/decentralised to a more distributed nature allowing each distributed generator to receive information from sensors at distant buses. In such systems, there is much interdependency between various power, control and communication parameters due to which the control of parameters from one domain gets affected by other. The central idea of this study is to develop a generic, hybrid and customised framework to jointly model the multi-disciplinary variables and their interactions present in the smart grid and to develop controllers in an adaptive manner to ensure better control of physical variables such as voltage irrespective of the changes in operating point brought about by changes in physical/cyber parameters. Hence, the different operating conditions of the power system have been modelled as multiple subsystems of a hybrid switching system and controller design is carried out by solving the optimisation formulations developed for delay-free and delay-existent cases using the theory of common Lyapunov function. The optimisation is carried out using the block coordinate descent methodology by converting the non-convex formulation into a series of convex problems to obtain a solution.

Resource Allocation in Electrical/Optical Hybrid Switching Data Center Networks

Hybrid switching combines the strengths of electronic packet switching and high-speed optical circuit switching and is thus widely believed to be a cost-effective solution for current and future data center networks (DCNs). In designing a hybrid switching DCN, it is essential to know how many resources should be devoted to optical circuit switching and electronic packet switching so the performance requirements in both planes can be satisfied, and, at the same time, objectives such as minimizing the overall system building cost or the power consumption can be realized. In this paper, we introduce BLOC, the Blocking LOss Curve, as a tool to characterize hybrid switching DCNs. With BLOC, the three interacting components in hybrid switching systems-resource allocation, traffic partitioning, and system performance-can be naturally integrated and studied together. We show how BLOC can be used to obtain feasible resource allocation/traffic partition combinations. We also show how system parameters, such as flow arrival characteristics, may affect resource allocation and system costs. Our study reveals that the total amount of resource required to satisfy 95th percentile traffic can be as low as 60% of that required for 99.9th percentile traffic.

Investigation and System Implementation of Flexible Bandwidth Switching for a Software-Defined Space Information Network

This paper proposes and experimentally demonstrates a hybrid switching system that provides flexible bandwidth allocation for future laser and microwave space information networks. First, a switching node structure is designed for laser and microwave hybrid links, and an optimized strategy of flexible bandwidth allocation is presented based on the traffic distribution. Then, we establish a reconfigurable light and microwave hybrid switching system based on microwave photonics. The experimental results indicate that the proposed system can realize microwave frequency conversion and photoelectric hybrid switching. Additionally, bandwidth resources can be allocated flexibly and the bit-error rate of the baseband data is less than 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−9</sup> . Furthermore, the simulation results of the proposed flexible bandwidth allocation strategy reveal that the spectrum utilization rate is more than 94% when the traffic is saturated.

Investigation into Limitation of Arc Erosion in LV Switches Through Application of Hybrid Switching

In this paper, measurement results of the arc erosion limitation in low voltage (LV) switches are presented. The reduction of the arc erosion in the analyzed electromechanical switches was achieved through an application of the hybrid switching in the tested alternative current circuit during interruption of the inductive current. The presented method is based on a commutation of the current during its interruption into a semiconductor branch that is connected in parallel to the operated switch. Thus, this approach is able to limit the electric arc energy efficiently, and as a consequence the arc erosion of the electrical contacts is also significantly reduced. For this reason, the application of the hybrid switching has a positive influence on a lifespan and a reliability of the operated switch. In order to evaluate the influence of the hybrid switching application on an effectiveness of the limitation of the arc erosion in the analyzed LV switches, 50 000 current interruptions were conducted in the tested circuit by each of four analyzed switches. Researches were performed for two standalone switches during a standard current interruption, as well as, for two switches with applied the hybrid switching system. In order to compare the arc erosion of the contact surfaces in both considered cases, scanning electron microscope method coupled with energy dispersion spectroscopy was applied. Moreover, photos of the electric contact surfaces are presented. Additionally, frames registered by high-speed camera during current interruption are presented for both considered approaches.

BLOC: A Generic Resource Allocation Framework for Hybrid Packet/Circuit-Switched Networks

In the current Internet, large flows co-exist with small flows and often consume a significant proportion of the network bandwidth. This imposes a challenge on network resource management. Various hybrid switching architectures have been proposed in recent years, aiming to address this challenge and improve energy efficiency and resource utilization. However, there is still a need for means for the design and dimensioning of resources in multiple switching planes and understanding the system behavior under different traffic patterns. In this paper, we propose a framework that we call the blocking-loss curve (BLOC) to address the resource allocation problem in hybrid switching systems. BLOC can capture the behavior of hybrid switching systems under different resource allocation solutions considering packet loss and request blocking. This framework also allows us to identify the feasible region for resource allocation, which can satisfy both the packet loss and request blocking requirements. An optimal resource allocation strategy may be found based on this feasible region. We also study the application of BLOC to a specific hybrid switching system, where packet switching comprises TCP flows with active queue management, and circuit switching is single granular, e.g., lightpath switching. Numerical results demonstrate how the flow characteristics and system parameters may affect the feasible region and the optimal allocation of resources.

Analytic–numerical approach in modeling electrodynamic phenomena of inductive dynamic drive

Inductive dynamic drives (IDD) are used in hybrid switching systems where a very quick contact separation as well as operation repeatability and long-term reliability are required. This paper presents more important existing examples of modeling the drive and their criticism. The author proposes a better model of electrodynamic inductive drive. Due to the cylindrical symmetry of the drives involved, a number of analytical dependencies were applied to develop the mathematical models. Additionally, the paper presents research results for a physical IDD model, those results determining the application range for the electrodynamic model assuming that the driven disc is perfectly stiff. Magnetic pressure acting on the disc obtained from the electrodynamic model can used as input in the mechanical model.

Real-Time Hybrid Switching Control of Automotive Cold Start Hydrocarbon Emission

Reduction of cold start hydrocarbon (HC) emissions requires a proper compromise between low engine-out HC emission and fast light-off of the three way catalytic converter (TWC). In this paper, a hybrid switching system is designed and optimized for reducing HC emissions of a mid-sized passenger car during the cold start phase of FTP-75 (Federal Test Procedure). This hybrid system has the benefit of increasing TWC temperature during the early stages of the driving cycle by switching between different operational modes. The switching times are optimized to reduce the cumulative tailpipe HC of an experimentally validated automotive emission model. The designed hybrid system is tested in real-time on a real engine control unit (ECU) in a model-in-the-loop structure. The results indicate the new hybrid controller reduces the HC emissions over 6.5% compared to nonswitching cold start controller designs.

Passivity-based control of hybrid impulsive and switching systems with singular structure

In this paper, stability, dissipativity, and passivity-based control of a class of hybrid impulsive switching systems with singular structures and uncertainties are investigated. Using switching Lyapunov functions, sufficient conditions for dissipativity and stability of those hybrid impulsive and switching singular systems are established. A switching control strategy is then presented. Finally, an example is given to illustrate the obtained results.

Necessary Optimality Conditions for a Class of Impulsive and Switching Systems

An optimal control problem for a class of hybrid impulsive and switching systems is considered. By defining switching times as part of extended state, we get the necessary optimality conditions for this problem. It is shown that the adjoint variables satisfy certain jump conditions and the Hamiltonian are continuous at switching instants. In addition, necessary optimality conditions of Fréchet subdifferential form are presented in this paper.

Stability analysis of a reduced model of the lac operon under impulsive and switching control

The study of the stability is an important motif in biological systems. Stability plays a significant role in some of the basic processes of life. In this paper, we provide a theoretical method for analyzing the exponential stability of a reduced model of the lac operon under the impulsive and switching control. Under the hybrid control, the reduced model becomes a nonlinear hybrid impulsive and switching system, and we get the sufficient conditions of its exponential stability. Finally, we give examples to illustrate the effectiveness of our method.

On optimal control problems of a class of impulsive switching systems with terminal states constraints

The global optimal control problem is proposed for a special class of hybrid dynamical systems, i.e. impulsive switching systems. Then the necessary condition of the above problem, the minimum principle, is given. Ekeland’s variational principle and the matrix cost functional structure expression are utilized in the process of the proof. Based on the main result, a special linear hybrid impulsive and switching system (HISS) is illustrated and the optimal control algorithm is presented. Moreover, the cases of pure impulsive systems and pure switched systems are included in this paper.

On hybrid impulsive and switching systems and application to nonlinear control

In this note, a new class of hybrid impulsive and switching models is introduced and their asymptotic stability properties are investigated. Using switched Lyapunov functions, some new general criteria for exponential stability and asymptotic stability with arbitrary and conditioned impulsive switching are established. In addition, a new hybrid impulsive and switching control strategy for nonlinear systems is developed. A typical example, the unified chaotic system, is given to illustrate the theoretical results.

An SFQ-based high-performance packet switch for next-generation high-end routers

Switching throughput capacities of over 10 Tbps will be required of high-end systems on the backbones of nationwide telecommunications networks within the next decade. However conventional technologies cannot accommodate such capacities. Superconducting single flux quantum (SFQ) technology is a promising approach because of its ultra-low power consumption and ultra-high speed characteristics. We have proposed an opto-electronic-SFQ hybrid switching system. This system is separated into three functions: SFQ packet switching, high-performance CMOS control, and optical transmission. The packet switch is an improved Batcher–Banyan switch that uses a time-shifted internal speedup unit, and shuffle and grouping exchange schemes. Simulation showed good scalability; no conventional router could ever attain this capacity. We report on the numerical analysis and architectural-level design results for this packet switch.