Synchronization Scheme Research Articles

An event-triggered synchronization strategy for high-precise clock systems with switching topologies

The clock synchronization is a key technology for the reliability of wireless sensor networks (WSN). To reduce the communication burden and address the challenge of clock synchronization for high-precise clock systems in WSN with switching topologies, this paper proposes an event-triggered synchronization strategy for high-precise clock systems. Firstly, based on the concept of offset and skew, the model of whole clock systems is investigated and an event-triggered strategy is proposed for high-precise clock systems with switching topologies. Then, a synchronization strategy for clock systems is presented to achieve clock synchronization with the convergence of clock offset and clock skew. The sufficient condition for the synchronization of high-precise clock systems with switching topologies is obtained. Afterwards, the optimal event-triggered weighting matrices and controller gains are calculated by converting the clock synchronization problem as a solvable optimization problem. Finally, the performance of the proposed clock synchronization method is evaluated by simulations.

Robust Symbol and Frequency Synchronization Method for Burst OFDM Systems in UAV Communication

This paper introduces a robust synchronization method for orthogonal frequency division multiplexing (OFDM) in multi-unmanned aerial vehicle (UAV) communication systems, focusing on minimizing overhead while achieving reliable synchronization. The proposed synchronization scheme enhances both frame efficiency and implementation simplicity. Initially, a high-efficiency frame structure is designed without a guard time interval, utilizing a preamble sequence to simultaneously achieve both symbol synchronization and automatic gain control (AGC) before demodulation. Subsequently, a novel 2-bit non-uniform quantization method for the Zadoff–Chu sequences is developed, enabling the correlation operations in the traditional symbol synchronization algorithm to be implemented via bitwise exclusive OR (XOR) and addition operations. The complexity of hardware implementation and the energy consumption for symbol synchronization can be reduced significantly. Furthermore, the impact of AGC on frequency synchronization performance is examined, and an improved frequency synchronization method based on AGC gain compensation is proposed. Finally, the performance of the proposed method is rigorously analyzed and compared with that of the traditional method through computer simulations, demonstrating the effectiveness and superiority of the proposed approach.

A new fixed-time sliding mode control scheme for synchronization of chaotic systems

Chaotic synchronization is crucial in the field of secure communication, and fixed-time synchronization has realistic application prospects and demands. Aiming at the traditional sliding mode synchronization control method with chattering problem, based on the Lyapunov stability theory and incorporating the continuous time fixed time stability theorem, this paper proposed a new fixed-time sliding mode control scheme for synchronization of chaotic systems. The traditional finite-time sliding mode synchronization is compared with the proposed fixed-time sliding mode synchronization scheme and the results are discussed. The efficacy of the controller is validated using MATLAB simulations, which eliminates the chatter problem in the traditional sliding mode synchronization scheme and has the advantage of short synchronization time. In addition, the parameters of the controller can be set flexibly, which is an advantage of the fixed-time synchronous control scheme.

A cooperative timestamp-free clock synchronization scheme based on fast unscented Kalman filtering for time-sensitive networking

Clock synchronization, built on the classical two-way message exchange scheme, is the key prerequisite for the normal operation of time-sensitive networking (TSN). In practical TSN, the imperfect oscillator caused by environmental changes leads to clock parameters drift. Moreover, synchronization errors accumulate in multi-hop networks, making it difficult for nodes at the edge of the network to achieve precise synchronization performance. Additionally, in some industrial and vehicular scenarios, the energy consumption and complexity of clock synchronization are important factors that need to be considered. To address these problems, this paper proposes a cooperative synchronization clock offset and clock skew joint tracking algorithm based on fast Unscented Kalman filter (FUKF). To further reduce the computation and energy consumption caused by clock synchronization, we introduce randomized singular value decomposition and timestamp-free exchange. The former uses small sub-matrices approximations to replace extremely high-dimensional matrices, reducing computational time in the update stage of the UKF. The latter reduces energy consumption by setting response intervals at the receiving end, eliminating the need for timestamp exchange during the synchronization process. Therefore, this algorithm can achieve long-term synchronization without requiring excessive computational and communication overhead. The results show that the proposed method, while maintaining accuracy unchanged, reduced the running time by 20% to 90% as the number of observations increased, thus verifying the effectiveness of the algorithm.

Synchronizing chaos: Exploring attractive sets in a novel 4D hyperchaotic Lorenz model

Due to the very complex algebraic structure of hyperchaotic models, it is often difficult to determine their limits. Using Lyapunov’s stability theory and optimization methods, we study the limits of a new 4D hyperchaotic Lorenz model. Based on the results obtained, we study complete chaotic synchronization. Finally, to demonstrate the effectiveness of the proposed chaotic synchronization scheme, some numerical simulations are provided.

Analysis of adaptive parameter tuning control strategy of VSG

Abstract The traditional virtual synchronous inverter employs constant inertia and damping control, resulting in poor reliability when the system faces disturbances. Consequently, this paper proposes a synchronous virtual machine network control strategy based on adaptive technology. Firstly, the traditional principle is analyzed, followed by an examination of the effects of varying inertia and damping levels on the power grid. Leveraging the power angle characteristic and frequency oscillation characteristic of synchronous generators, an inertia and damping adaptive control strategy is devised. Subsequently, the effectiveness of the strategy is validated through simulation curves generated by a Simlink model.

Frequency Division Multiplexing-Based Power/Signal Synchronous Transmission Strategy for IPOS-DAB DC/DC Converters

Frequency Division Multiplexing-Based Power/Signal Synchronous Transmission Strategy for IPOS-DAB DC/DC Converters

A Simple Event-Based Average Consensus Clock Synchronization Scheme in Industrial Wireless Sensor Networks Under Communication Delays

A Simple Event-Based Average Consensus Clock Synchronization Scheme in Industrial Wireless Sensor Networks Under Communication Delays

A secure communication scheme based on generalized modified projective synchronization of a new 4-D fractional-order hyperchaotic system

This paper focuses on the exploration of the chaotic behavior of a new 4-D fractional-order hyperchaotic system with five nonlinearities. The Adomian decomposition method is employed to solve the fractional-order hyperchaotic system. The stability of equilibrium points in this system is analyzed. Through bifurcation diagrams, Lyapunov exponent spectra, chaotic attractors, 0-1 test, C 0 complexity, and spectral entropy, the chaotic dynamics of the proposed system are investigated. Using these tools, we demonstrate the fractional-order system’s sensitivity to variation in both the derivative order and initial conditions. Moreover, a modified generalized projective synchronization is developed to implement chaos synchronization between two coupled fractional-order hyperchaotic systems. Furthermore, this work presents an application of synchronization scheme in secure communication. Numerical simulations were implemented to validate the effectiveness of the proposed secure communication scheme.

Finite-time H∞ synchronization of semi-Markov jump neural networks with two delay components with stochastic sampled-data control

This article investigates the finite-time H∞ synchronization for semi-Markov jump neural networks with two delay components based on stochastic sampled data control. Additionally, the parametric uncertainties are randomly varying which follows the Bernoulli distributed sequences. In the stochastic sampled data control, the sampling interval ′m′ is supposed to be two different values in the time-varying component with given probability conditions. By constructing triple and quadruple integral term in the Lyapunov-Krasovskii functional (LKF) a new integral inequality technique is addressed to derive the main results. Dissimilar from previous literature, involving the new integral inequality, a delay dependent finite-time H∞ synchronization requirements are acquired with regard to linear matrix inequalities (LMIs). In the end, the effectiveness of the considered stochastic sampled data control finite time synchronization scheme is highlighted by numerical examples.

The design, circuit realization and applications of chaotic system with offset-boosting and multistability

Based on the foundation of a three-dimensional Jerk chaotic system, a novel four-dimensional chaotic system based on a memristor with cosine magneto-memristor is proposed. The system’s dynamical behavior is analyzed using bifurcation diagrams, Lyapunov exponents, multiple bifurcation diagrams, two-parameter Lyapunov exponents, complexity, and attractor basins. It is found that this new chaotic system exhibits characteristics such as multistability, transient chaos, intermittent chaos, spike discharge, controllable multi-vortex, and offset-boosting. The chaotic system is designed and simulated in analog circuit and realized in a digital circuit using a Field-Programmable Gate Array (FPGA). The consistency between simulation results and implementation results demonstrates the existence and feasibility of the system. Finally, the significance and superiority of the control scheme are verified based on the adaptive anti-synchronization control strategy, and the synchronization strategy is applied to image encryption, and the results show that the encryption effect is excellent and the anti-jamming ability is strong.

A meta-analysis supporting the superiority of staged carotid artery stenting and coronary artery bypass grafting in patients with concurrent severe coronary and carotid artery stenosis.

This study sought to ascertain whether a staged approach involving carotid artery stenting (CAS) and coronary artery bypass grafting (CABG) holds superiority over the synchronous (Syn) strategy of CAS or carotid endarterectomy (CEA) and CABG in patients necessitating combined revascularization for concurrent carotid and coronary artery disease. Studies were identified through 3 databases: PubMed, EMBASE, and the Cochrane Library. Statistical significance was defined as a P value of less than .05 for all analyses, conducted using STATA version 12.0. In the comparison between staged versus Syn CAS and CABG for patients with concomitant severe coronary and carotid stenosis, 4 studies were analyzed. The staged procedure was associated with a lower rate of 30-day stroke (OR = 8.329, 95% CI = 1.017-69.229, P = .048) compared to Syn CAS and CABG. In the comparison between staged CAS and CABG versus Syn CEA and CABG for patients with concomitant severe coronary and carotid stenosis, 5 studies were examined. The staged CAS and CABG procedure was associated with a lower rate of mortality (OR = 2.046, 95% CI = 1.304-3.210, P = .002) compared to Syn CEA and CABG. The Syn CAS and CABG was linked to a higher risk of peri-operative stroke compared to staged CAS and CABG. Additionally, patients undergoing staged CAS and CABG exhibited a significantly decreased risk of 30-day mortality compared to Syn CEA and CABG. Future randomized trials or prospective cohorts are essential to confirm and validate these findings.

Frequency stability of new energy power systems based on VSG adaptive energy storage coordinated control strategy

A self-adaptive energy storage coordination control strategy based on virtual synchronous machine technology was studied and designed to address the oscillation problem caused by new energy units. By simulating the characteristics of synchronous generators, the inertia level of the new energy power system was enhanced, and frequency stability optimization was achieved. This strategy is integrated with the frequency response model of the new energy power system to improve the system's frequency regulation capability and achieve more stable and efficient operation. From the results, the damping of the system increased, the oscillation frequency decreased after a duration of about 15 s, and the system stability improved by 76.09%. The proposed strategy based on virtual synchronous generator adaptive energy storage coordination control strategy was improved by 83.25%. In addition, the proposed strategy has improved stability indicators and system completion efficiency by 40.57% and 22.21% respectively, both of which are better than the comparative strategies. As a result, this strategy significantly enhances the frequency regulation capability of the system, which has a positive effect on achieving efficient operation of the new energy power system and maintaining the stability of the power system.

A read-efficient and write-optimized hash table for Intel Optane DC Persistent Memory

Emerging non-volatile memory technologies are driving the next generation of storage systems and durable data structures. Among them, many hash table proposals employ NVM as the storage layer for both fast access and efficient persistence. Most of them are based on the assumption that NVM has cacheline access granularity, poor write endurance, DRAM-comparable read latency and relatively higher write latency. However, a commercial non-volatile memory product, namely Intel Optane DC Persistent Memory (Optane), has some interesting features that are different from previous assumptions, such as 256-byte OptaneLine access granularity, higher read latency than DRAM and DRAM-comparable write latency, limited read/write bandwidth, and hardware-layer wear-leveling. Confronted with the new challenges brought by Optane, we propose Rewo-Hash, a novel read-efficient and write-optimized persistent hash table. Our incremental contributions over our previous work are summarized as follows. First, provide a more detailed technical description for cached table-inclined read mechanism and log-free atomic write mechanism. Second, we devise a consistent shadowing synchronization scheme to mask the data synchronization overhead. Third, we propose a non-blocking lightweight resizing scheme and elaborate the crash recovery mechanism. Fourth, we conduct a comprehensive analysis of the implications of Intel ceasing the production of Optane, and provide a forward-looking perspective on the future of non-volatile memory. The experimental results show that compared with state-of-the-art NVM-Optimized hash tables, Rewo-Hash gains remarkable performance improvement.

Macro-micro synchronization strategy based on fuzzy time-delay compensation for high-precision laser on-the-fly processing

Real-time control systems of macro-micro manipulators commonly confront time-delay challenges to achieve high precision and synchronization performance, because macro and micro subsystems always have significant difference mainly in mechanical inertia. In this paper, a self-designed PC-based real-time controller utilized in laser on-the-fly processing is introduced as a study case of macro-micro systems. A dynamic time-delay compensation method for this case is proposed based on efficient fuzzy-model prediction and special data compression/extension algorithm. This method takes account of the practical time-delay fluctuation and has capability of adjusting the compensator adaptively rather than fixing the compensator as a constant, compared with the conventional static compensation. Experimental results show that, after applying the dynamic compensation, the process error caused by time-delay is eliminated from 1.059 mm to 0.001 mm, while the quality of synchronization appears even better than the static compensation with the error of 0.014 mm. Besides, the proposed method is computationally optimized, and the extra load of real-time kernel merely fluctuates within 3 % of the total computation performance capacity.

Jerk Chaotic System: Analysis, Circuit Simulation, Control and Synchronization with Application to Secure Communication

Dynamical behaviors of 3D Jerk system were examined in terms of equilibrium, stability, dissipative, and phase space attractor in this study. The system’s practical applications were demonstrated through circuit realization and synchronization scheme via active backstepping control with its effectiveness demonstrated in secure communication. The viability of the theoretical model of 3D Jerk system was confirmed using electronic circuit workbench designed in MultiSIM enviroment. A nonlinear feedback controller was designed using the recursive backstepping technique to control and track a desire function. For secure communication application, active backstepping method was adopted to synchronize two identical chaotic systems evolving from different initial conditions. It was demonstrated that when the controller was activated, the systems synchronize successfully. The results of the active backstepping designed controllers were numerically applied in the area of secure communication, with the variable of the drive being encrypted information transmitted through a coupling channel. Using an additive encryption masking scheme, the encrypted signal was a superposition of sinusoidal information specified by period function and chaotic carrier generated from a variable of the Jerk system. The transmitted information signal was successfully retrieved from the chaotic response signal using an inverse function decryption algorithm, thereby confirming the effectiveness and robustness of the designed controller.

The Distributed Multi Constrained Channel Access Mechanism By Using Framework For Mobile Adhoc Network

The Mobile Ad hoc Network (MANET) is an autonomous wireless communication system, and does not have any fixed infrastructure. The Network loads which arise due to application evolving using MANET environment has to balance using routing protocol. Networks are increasingly resource intensive to efficiently manage the bandwidth & Energy in the group communication on basis of addressing the routing issues to provide the enhanced functionality of the network on basis of channel utilization and channel conditioning against load balancing. In this research, proposed a novel unified framework for Distributed multi constrained Channel Access Mechanism for mobile Adhoc Network on inclusion of Scheduled Throughput Discriminant Multi-Data synchronization Strategies for Channel Allocation in Mobile Adhoc Network on various traffic patterns, Multi Trajectory Particle Swarm Optimization towards Optimal Velocity Control against load balancing and band width controlling and finally Self Adaptive Redundancy Elimination Clustering and Distributed Load Bandwidth Management Constraints for Mobile Ad Hoc Network.

Photovoltaic Power Injection Control Based on a Virtual Synchronous Machine Strategy.

The increasing participation of photovoltaic sources in power grids presents the challenge of enhancing power quality, which is affected by the intrinsic characteristics of these sources, such as variability and lack of inertia. This power quality degradation mainly generates variations in both voltage magnitude and frequency, which are more pronounced in microgrids. In fact, the magnitude problem is particularly present in the distribution systems, where photovoltaic sources are spread along the grid. Due to the power converter's lack of inertia, frequency problems can be seen throughout the network. Grid-forming control strategies in photovoltaic systems have been proposed to address these problems, although most proposed solutions involve either a direct voltage source or energy storage systems, thereby increasing costs. In this paper, a photovoltaic injection system is designed with a virtual synchronous machine control strategy to provide voltage and frequency support to the grid. The maximum power point tracking algorithm is adapted to provide the direct voltage reference and inject active power according to the droop frequency control. The control strategy is validated through simulations and key experimental setup tests. The results demonstrate that it is possible to inject photovoltaic power and provide voltage and frequency support.

Alone, together: how a strategy of writing, reflecting and relating helped research students deal with isolation

PurposeThe purpose of this research is to assess the impact of the synchronous online teaching strategy on higher degree research students, particularly those dealing with isolation. The aim is to enhance their coping mechanisms and writing productivity, fostering a supportive learning environment.Design/methodology/approachThis study employed surveys to evaluate the effectiveness of a synchronous online teaching strategy designed for Higher Degree Research students who may experience isolation. The strategy incorporated activities involving writing, reflection, and peer interaction, targeting students who prefer social and solitary learning.FindingsThe results indicate that the teaching strategy significantly benefited a majority of higher degree research students, promoting skill improvement in writing, reflection, and meaningful connections within the student community. Notably, it exhibited the strongest positive correlation with solitary learners, particularly in terms of social connection, reducing their sense of isolation.Research limitations/implicationsThis research underscores the potential of tailored teaching strategies in addressing isolation among Higher Degree Research students, acknowledging limitations including reliance on surveys. The study’s findings have significance for pedagogical design in online and blended learning environments, offering strategies to combat isolation and enhance the student experience while supporting diverse learning preferences. Further investigation into different learning contexts and demographics is also warranted.Originality/valueThis research contributes to the field by demonstrating the positive impact of a synchronous online teaching strategy on higher degree research students, particularly those prone to isolation. It emphasises the value of tailored approaches in enhancing their educational experience and combating feelings of solitude.

Adaptive Synchronization and Pacing Control for Visual Interactive Simulation

Parallel and distributed computing enable the execution of large and complex simulations. Yet, the usual separation of (headless) simulation execution and (subsequent, offline) output analysis often renders the simulation endeavor long and inefficient. Recently, Visual Interactive Simulation (VIS) tools and methods that address this end-to-end efficiency are gaining relevance, offering in-situ visualization, real-time debugging, and computational steering. Here, the typically distributed computing nature of the simulation execution poses synchronization challenges between the headless simulation engine and the user-facing frontend required for Visual Interactive Simulation. To the best of our knowledge, state-of-the-art synchronization approaches fall short due to their rigidity and inability to adapt to real-time user-centric changes. This paper introduces a novel adaptive algorithm to dynamically adjust the simulation’s pacing through a buffer-based framework, informed by predictive workload analysis. Our extensive experimental evaluation across diverse synthetic scenarios illustrates our method’s effectiveness in enhancing runtime efficiency and synchronicity, significantly reducing end-to-end time while minimizing user interaction delays, thereby addressing key limitations of existing synchronization strategies.