Hybrid Switching Research Articles

Analysis of Envelope-Tracking Power Amplifier Using Mathematical Modeling

This paper describes analysis of an envelope-tracking power amplifier (ET PA) to show its operational behavior. The RF PA is modeled by sweeping the input power and supply voltage. The RF PA model is composed of three 2-D lookup tables including the amplitude-to-amplitude modulation, amplitude-to-phase modulation, and amplitude-to-efficiency modulation. The hybrid switching supply modulator is also modeled using an ideal op-amp, ideal switches, and other assisting blocks. Based on the mathematical models of the RF PA and supply modulator, the ET PA can be analyzed with a fast calculation speed and a good accuracy to find the optimum ET operation point. A power control strategy is presented for the optimal ET operation over a broad output power range. The effect of the delay mismatch on the characteristics of the ET PA is also described to assist the time alignment algorithm. For a 10-MHz long-term evolution signal with a 7.44-dB PAPR, the implemented ET PA at 1.71 GHz delivers a PAE of 44.3%, a gain of 29 dB, an evolved universal terrestrial radio access adjacent channel leakage ratio of -35.1 dBc, and an error vector magnitude of 2.91% at an average output power of 28 dBm.

Stability of complex-valued impulsive and switching system and application to the Lü system

In this paper, the stability of complex-valued impulsive and switching system is addressed. By using switched Lyapunov functions on a complex field, some new stability criteria of complex-valued impulsive and switching systems are established, which not only generalize some known results in the literature, but also greatly reduce the complexity of analysis and computation. As an application, a new hybrid impulsive and switching feedback controller for the complex-valued chaotic Lü system is designed.

On hybrid control of higher order Boolean networks

In the present paper, we discuss the stabilization and controllability issues of the hybrid switching and impulsive higher order Boolean networks. First, the hybrid switching and impulsive controller is introduced. Second, the algebraic form of the system is given. Third, sufficient and necessary conditions for the stabilization and controllability of the system are presented, respectively. At last, an illustrative example shows the effectiveness of the main results.

Experimental Validation of a Cascaded Single Phase H-Bridge Inverter with a Simplified Switching Algorithm

This paper presents a new cascaded asymmetrical single phase multilevel converter with a lower number of power semiconductor switches and isolated DC sources. Therefore, the number of power electronic devices, converter losses, size, and cost are reduced. The proposed multilevel converter topology consists of two H-bridges connected in cascaded configuration. One H-bridge operates at a high frequency (high frequency inverter) and is capable of developing a two level output while the other H-bridge operates at the fundamental frequency (low frequency inverter) and is capable of developing a multilevel output. The addition of each power electronic switch to the low frequency inverter increases the number of levels by four. This paper also introduces a hybrid switching algorithm which uses very simple arithmetic and logical operations. The simplified hybrid switching algorithm is generalized for any number of levels. The proposed simplified switching algorithm is developed using a TMS320F2812 DSP board. The operation and performance of the proposed multilevel converter are verified by simulations using MATLAB/SIMULINK and experimental results.

QBNoC: QoS-aware bufferless NoC architecture

Chip area and power consumption are the main restrictions for Network-on-Chip (NoC), a high proportion of which is consumed by the buffers in the routers. Therefore, bufferless NoC, which completely eliminates in-router buffers, has been proposed. However, the existing bufferless NoC designs do not provide Quality-of-Service (QoS) guarantee. In this paper, we propose a QoS-aware Bufferless NoC, named QBNoC. QBNoC employs hybrid switching mechanism, namely circuit switching mechanism for real-time application and wormhole switching mechanism for other applications. Besides, in order to decrease the deflection probability and thus improve the performance of the network, we propose a new output port allocation policy, named Two-Stage Allocation (TSA). Furthermore, new router architecture with shorter critical path is designed for QBNoC. The evaluation results show that by efficiently exploiting resources, our proposal significantly improves the performance of the whole network, and meanwhile satisfies the QoS requirements of different applications.

EVALUATION OF HIDDEN MARKOV MODEL BASED ADAPTIVE PROVISIONING OF OPTICAL BURST SWITCHING NETWORKS AMENABLE FOR UPGRADATION TO GREEN FLEXIGRID NETWORKS

Catering to the evolving bandwidth-on-demand applications requires flexible provisioning architectures that ensure fairness to both high end and low end users of internet. Dynamic classification of network path s into long and short, based on traffic dependent connecti on holding times and a wavelength allocation from different subsets for these categories is a necessi ty for implementing energy saving hybrid switching, loss recovery and flexi grid bit rate variable schemes. Therefore, this study evaluates such a scheme of d ynamic classification based on HMM predicted connection-holding times with tightly integrated adaptive burst sizing and segregated wavelength allocation for lon g and short categories. Simulation study of a 28 no de OBS network shows that this coupled scheme reduces delays and results in throughput improvement of 67% for long and 12% for short traffic over schemes tha t employ adaptive burst sizing based on number of a ctive traffic flows and independent wavelength assignment schemes.

Enhancing Performance of Cloud Computing Data Center Networks by Hybrid Switching Architecture

Cloud computing services have driven a new design of data center networks. Hybrid switching architecture is one of the promising solutions since it makes better tradeoff between the network performance and technical feasibility. However, as the existing hybrid networks only deploy one-hop optical circuit switching (OCS) in the top layer, the flexibility and scalability is limited. To address this problem, a distributed OCS model is proposed. To reduce the high blocking ratio, the WDM and SDM technologies are introduced to increase the connectivity of the optical network. Moreover a multi-wavelength optical switch based on microring resonators is designed to enable the fast switching. Based on this model, the multi-rooted tree based hybrid architecture with deep integration of optical connection is constructed. A new way to solve the mixed traffic scheduling problem is also provided by delivering the small flows and large flows through the different networks. The simulation results indicate that the multi-rooted tree based hybrid architecture achieves better performance under various traffic patterns. It also introduces less control overhead compared with the existing traffic scheduling schemes.

A Cascaded Multi-level Inverter Topology with Improved Modulation Scheme

This article proposes a single-phase, cascaded multilevel inverter topology. Each of the cascaded unit cells is made up of a main inverting H-bridge leg and a level-clamping half-bridge circuit. The single-carrier, multilevel pulse-width modulation scheme is employed to generate gating signals fort he power switches. The modulation scheme is hybridized to enable the output voltage of the proposed inverter configuration, inherit the features of switching-loss reduction from fundamental pulse-width modulation, and good harmonic performance from multiple sinusoidal pulse-width modulation. A sequential switching scheme is embedded with the already employed hybrid modulation to overcome unequal switching losses among the power devices. A simple base pulse-width modulation circulation scheme is also introduced in this work to get resultant sequential switching hybrid pulse-width modulation circulation that balances power dissipation among the power modules. The proposed inverter configuration was subjected to a resistor-inductor load, and the respective numbers of output voltage level were synthesized. Fast Fourier transform (FFT) analyses of the output voltage waveforms were carried out. Analysis of the conduction power losses in the power semiconductor switches of the proposed inverter topology is given. Simulations and experiments are carried out on a 3.07-kW rated prototype of the proposed inverter for a resistor-inductor load.

Stability of Hybrid Stochastic Systems with Time-Delay

This paper develops some criteria for a kind of hybrid stochastic systems with time-delay, which improve existing results on hybrid systems without considering noises. The improved results show that the presence of noise is quite involved in the stability analysis of hybrid systems. New results can be used to analyze the stability of a kind of stochastic hybrid impulsive and switching neural networks (SHISNN). Therefore, stability analysis of SHISNN can be turned into solving a linear matrix inequality (LMI).

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.

Chaotification of a Class of Linear Switching Systems by Hybrid Driven Methods

This paper investigates a class of linear continuous-time switching systems and proposes a new approach to generate chaos by designing a hybrid switching rule. First, a computational formula for Lyapunov exponents is derived by extending the definition of Lyapunov exponent for continuous-time autonomous systems to that of a class of linear continuous-time switching systems. Then, a novel switching rule is proposed to gain global boundedness property as well as the required placement of Lyapunov exponents for chaos. A numerical example is given to illustrate the chaotic dynamic behavior of the generated system. The Lyapunov dimension of the system in the example is calculated and the corresponding bifurcation diagram and Lyapunov spectra are sketched, which, together with other phase portraits, clearly verify the validity of the main result.

Design of a hybrid switching architecture for avionic WDM platforms

A novel hybrid switching architecture using optical circuit switching for intra-subnet communication and fiber channel (FC) for inter-subnet communication is proposed. The proposed scheme utilizes small-size arrayed waveguide grating routers (AWGRs) and legacy FC switches to construct the large-scale avionic network, thus has the potential of the lower latency, the satisfactory network bandwidth and the lower power consumption. The simulation results verify that the proposed architecture outperforms FC switched architecture in terms of real time performance and power consumption.

Switching Hybrid Control of Blood Glucose in Diabetic Göttingen Minipigs

This paper presents the results of our recent blood glucose control trials with diabetic Göttingen minipigs. In particular, we describe our new switching hybrid control algorithm which uses different sampling intervals and insulin application strategies for daytime and night phases. The experimental results of the control application to two animals are given and compared with manual insulin treatment. Both strategies for glucose regulation result in comparable blood glucose trajectories even though meals were not announced to the controller but were taken into account in the manual protocol.

Coding embedded hybrid switching fabric applications in next generation power system backbone

With the advent of the new information technologies, the power communication service object is continuously improved by the modernization level of the electric power industry. The long term planning goal is not only to provide a transmission pipeline of power dispatching, but also a variety of service type, which requires a reliable and high efficiency power system communication network. Previous researches on the wide area protection propose a feasible solution on adaptive protection by using IP/SDH-based WAN. With the increasing capacity requirement, tradition IP/SDH device will be replaced gradually by the optical transport network. In this paper, we propose a novel hybrid switching fabric reconfigurable optical add-drop multiplexer/optical cross-connect (ROADM/OXC) by using electric coding embedded approach on the high speed backbone router. Also, the corresponding hybrid switching network coding (HSNC) scheme is propose to implement real-time cross-connect operation. HSNC schemes are integrated with MAWAPS of previous research and the results show that it is an efficient approach for various granularities switching structure. Performance of HSNC under different switching ratio and fiber core is presented and is also compared with traditional approach, and it is concluded to be a competitive approach that can be widely used in the next generation power grid backbone.

Is Always a Hybrid Recommender System Preferable To Single Techniques?

Collaborative filtering (CF) recommender systems are typically unable to generate adequate recommendations in sparse datasets. Empirical evidence suggests that incorporation of a trust network among the users of a recommender system can significantly help to alleviate this problem. For this reason, some studies have been done on combining CF with trust-enhanced recommender system. In this study, we analyze the switching hybrid recommender system with the CF and trust-enhanced recommender system components from both rating coverage and mean absolute error point of view. Experiments on a dataset from Epinions.com prove that, although the rating coverage of this hybrid method is better than both (CF and trust-enhanced RS), but has lower accuracy than just using trust-enhanced RS. In other words, trust-enhanced RS outperforms the hybrid recommender system consisting of CF and trust-enhanced RS. Finally, we justify this result using analytical method.

Small Multi-Agent Wind Solar Hybrid Power Generation System Design and Implementation

This paper introduces a method of design and implementation of wind-solar hybrid power generation system based on multi-agent. The paper mainly introduces the system hardware structure chart and the parameters design of Buck-Boost circuit. It also introduces the software design of wind power and solar power generation agent module and storage battery charging and discharging agent module. Finally the system wind solar hybrid switching waveforms are analyzed, the waveform analysis can show that the circuit switch is normal and work stably.

Scalable, Low-Energy Hybrid Photonic Space Switch

A scalable monolithically integrated photonic space switch is proposed which uses a combination of Mach-Zehnder modulators and semiconductor optical amplifiers (SOAs) for improved crosstalk performance and reduced switch loss. This architecture enables the design of high-capacity, high-speed, large-port count, low-energy switches. Extremely low crosstalk of better than -50 dB can be achieved using a 2 × 2 dilated hybrid switch module. A “building block” approach is applied to make large port count optical switches possible. Detailed physical layer multiwavelength simulations are used to investigate the viability of a 64 × 64 port switch. Optical signal degradation is estimated as a function of switch size and waveguide induced crosstalk. A comparison between hybrid and SOA switching fabrics highlights the power-efficient, high-performance nature of the hybrid switch design, which consumes less than one-third of the energy of an equivalent SOA-based switch. The significantly reduced impairments resulting from this switch design enable scaling of the port count, compared to conventional SOA-based switches.

A New Relay and Jammer Selection Schemes for Secure One-Way Cooperative Networks

This paper presents different relay and jammer selection schemes for one-way cooperative networks to increase the security against malicious eavesdroppers. We consider a single source-destination cooperative network with multiple intermediate nodes and one or more eavesdroppers. The selection in the proposed schemes is made with the presence of direct links and the assumption that the broadcast phase is unsecured. The proposed schemes select three intermediate nodes. The first selected node operates in the conventional relay mode and assists the source to deliver its data to the corresponding destination via a Decode-and-Forward strategy. The second and third selected nodes are used in different communication phases as jammers to create intentional interference at the eavesdroppers' nodes. Moreover, a hybrid scheme which switches between jamming and non-jamming modes is introduced in this paper. The proposed schemes are analyzed in terms of ergodic secrecy capacity and secrecy outage probability. Extensive analysis and a set of simulation results are presented to demonstrate the effectiveness of the different schemes presented in this work. The obtained results show that the proposed schemes with jamming outperform the conventional non-jamming schemes and the hybrid switching scheme further improves the secrecy capacity. The impact of changing both the eavesdroppers and the relays location on ergodic secrecy capacity and secrecy outage probability is also discussed. Finally, the impact of the presence of multiple eavesdroppers is studied in this paper.

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.

Exponential synchronisation of hybrid impulsive and switching dynamical networks with time delays

This study formulates and studies a model of hybrid impulsive and switching dynamical networks with time delays. There are two separable switching functions acting on the network. One drives inherent network structures and the other induces finite-state feedback in the control law. These hybrid networks have both continuous-time and discrete-time dynamics. At each moment, the coupling structure changes from one graph to another. At the same time, the continuous state variables may jump from one value to another. Time delays considered in this paper exist in isolated dynamical nodes, interconnections and impulsive noise disturbances. Based on Lyapunov stability theory, some new sufficient criteria are derived for exponential convergence of disagreement dynamics, which implies that network synchronisation of such hybrid-delayed network is achieved. An illustrative example of a delayed chaotic network with switching topology and impulse effects is used to demonstrate the main results.