Synchronization Scheme Research Articles

Scalable control of cluster synchronization in a chaotic, directed, complex semiconductor laser network

With the rapid growth of information technology, controlling the synchronization of large-scale networks has become more challenging and costly. To address this, we propose a scalable regulation scheme of cluster synchronization in a directed complex semiconductor lasers (SLs) network. The stability of chaotic synchronization for the entire network could be scalably regulated by only modifying the parameters of the driver cluster based on the hierarchical dependency of cluster synchronization in directed network, thus improving the control efficiency and reducing costs. The influence of parameters associated with the driver cluster is discussed systematically, and we numerically and experimentally demonstrate that a complex SLs network could achieve ideal cluster synchronization with the introduction of the proposed scalable regulation scheme. At last, encrypting and decrypting images is realized by leveraging the controlled chaotic cluster synchronization in complex, SLs networks.

Analysis on dynamic characteristics and control strategy of medium structure network converter in new energy medium voltage flexible interconnection project

Abstract In view of the possible voltage and current overshoot problems in the process of new energy grid connection, the dynamic characteristics analysis and control strategy of the network converter in the new medium voltage flexible interconnection project are proposed. Firstly, a synchronous control strategy based on voltage phase and amplitude compensation is proposed. Then, based on the characteristics of new AC-DC hybrid distribution network, the new energy medium voltage flexible interconnection network is analyzed. The simulation experiment reveals the dynamic response characteristics of the new energy grid converter under frequency interference and load change.

520 μJ Microsecond Burst-Mode Pulse Fiber Amplifier with GHz-Tunable Intra-Burst Pulse and Flat-Top Envelope

We present a 520 μJ microsecond burst-mode pulse fiber amplifier with a GHz-tunable intra-burst repetition rate and a nearly flat-top pulse envelope. The amplifier architecture comprises a microsecond pulse seed, a high-bandwidth electro-optic modulator (EOM), two pre-amplifier stages, a waveform-compensated acoustic-optic modulator (AOM), and two main amplifier stages. To address amplified spontaneous emission (ASE) and nonlinear effects, a multistage synchronous pumping scheme that achieved a maximum energy output of 520 μJ and has a peak power of 160 W was used. To produce a flat-topped burst pulse envelope, the AOM generates an editable waveform with a leading edge and a high trailing edge to compensate for waveform distortion, resulting in a 5 μs nearly flat-top pulse envelope at maximum energy. The laser provides an adjustable intra-burst pulse repetition rate range of 1–5 GHz through the high-bandwidth EOM modulation. The intra-burst pulse jitter time of the laser remains below 4.31 ps at different frequencies. Moreover, the beam quality of the amplifier is M2x = 1.04 and M2y = 1.1. This amplifier exhibits promising potential and can be further amplified as an optical drive source for high-power, large-bandwidth microwave photon (MWP) radar applications. Meanwhile, it is also potentially applicable as a pulse source for high-speed optical communications, the high-precision processing of special materials, and LIDAR ranging.

Oral Akkermansia muciniphila Biomimetic Nanotherapeutics for Ulcerative Colitis Targeted Treatment by Repairing Intestinal Epithelial Barrier and Restoring Redox Homeostasis.

The structural disruption of intestinal barrier and excessive reactive oxygen/nitrogen species (RONS) generation are two intertwined factors that drive the occurrence and development of ulcerative colitis (UC). Synchronously restoring the intestinal barrier and mitigating excess RONS is a promising strategy for UC management, but its treatment outcomes are still hindered by low drug accumulation and retention in colonic lesions. Inspired by intestine colonizing bacterium, we developed a mucoadhesive probiotic Akkermansia muciniphila-mimic entinostat-loaded hollow mesopores prussian blue (HMPB) nanotherapeutic (AM@HMPB@E) for UC-targeted therapy via repairing intestinal barrier and scavenging RONS. After oral administration, the negatively charged AM@HMPB@E specifically bind to the positively charged inflamed colon lesions via electrostatic interactions and Akkermansia muciniphila membrane-mediated bioadhesion mechanism. Subsequently, the superoxide dismutase (SOD)-, and catalase (CAT)-like HMPB eliminated RONS, thereby alleviating RONS-mediated inflammation and intestinal epithelial damage. Meanwhile, the UC-site locally released entinostat could repair the damaged intestinal epithelial barrier by inhibiting intestinal endothelial cell apoptosis and up-regulating the expression of tight junctions. Both in vitro and in vivo results shown that AM@HMPB@E not only exhibited an exceptional retention in the colitis site but also demonstrated superior therapeutic efficacy compared to the first-line drug sulfasalazine, as evidenced by the longer colon, less rectal bleeding and body weight loss. Collectively, our findings highlight the clinical application prospects of this synchronous nanotherapeutic strategy for UC treatment, offering a paradigm for the rational design of oral nanomedicine.

Experimental demonstration of 8190-km long-haul semiconductor-laser chaos synchronization induced by digital optical communication signal

Common-signal-induced synchronization of semiconductor lasers have promising applications in physical-layer secure transmission with high speed and compatibility with the current fiber communication. Here, we propose an ultra-long-distance laser synchronization scheme by utilizing random digital optical communication signal as the common drive signal. By utilizing the long-haul optical coherent communication techniques, high-fidelity fiber transmission of the digital drive can be achieved and thus ultra-long-distance synchronization is expected. Experiments were implemented with distributed feedback lasers injected by a random-digital phase-modulated drive light. Results show that high-quality synchronization can be achieved as the drive signal rate is larger than the laser relaxation frequency and the transmission bit error ratio is below a critical value. Chaos synchronization over 8191-km fiber transmission was experimentally achieved. Compared to traditional common-signal-induced synchronization using analog drive signal such as chaos, the distance is increased by 8 times, and complicated hardware devices for channel impairment compensation are no longer required. In addition, the proposed method does not sacrifice communication capacity like traditional methods which need a channel to transmit analog drive signal. It is therefore believed that this common-digital-signal induced laser synchronization paves a way for secure backbone and submarine transmission.

Preamble Design and Noncoherent ToA Estimation for Pulse-Based Wireless Networks-on-Chip Communications in the Terahertz Band.

The growing demand for high-speed data transfer and ultralow latency in wireless networks-on-chips (WiNoC) has spurred exploration into innovative communication paradigms. Recent advancements highlight the potential of the terahertz (THz) band, a largely untapped frequency range, for enabling ultrafast tera-bit-per-second links in chip multiprocessors. However, the ultrashort duration of THz pulses, often in the femtosecond range, makes synchronization a critical challenge, as even minor timing errors can cause significant data loss. This study introduces a preamble-aided noncoherent synchronization scheme for time-of-arrival (ToA) estimation in pulse-based WiNoC communication operating in the THz band (0.02-0.8 THz). The scheme transmits the preamble, a known sequence of THz pulses, at the beginning of each symbol, allowing the energy-detection receiver to collect and analyze the energy of the preamble across multiple integrators. The integrator with maximum energy output is then used to estimate the symbol's ToA. A preamble design based on maximum pulse energy constraints is also presented. Performance evaluations demonstrate a synchronization probability exceeding 0.98 for distances under 10 mm at a signal-to-noise ratio of 20 dB, with a normalized mean squared error below 10-2. This scheme enhances synchronization reliability, supporting energy-efficient, high-performance WiNoCs for future multicore systems.

Multi-rate sampled-data observer-based networked load frequency control for multi-area interconnected power systems under multiple cyber-attacks

This paper addresses the problem of adaptive event-triggered load frequency control (LFC) for multi-rate sampling multi-area interconnected power systems with integrated renewable energy. Different network channels can be vulnerable to multiple cyber-attacks, including deception attacks and DoS attacks. First, a matching mechanism is constructed to fuse the multi-rate sampled data, and a set of observers based on multi-rate sampled data is designed to independently estimate the states of the individual power systems. A networked sampled-data PI controller is then developed by introducing a new synchronous sampling scheme and an adaptive event-triggered mechanism. A co-design approach is proposed that integrates decentralized PI controllers, observers, and adaptive event-triggered mechanisms to achieve exponential mean-square stability with a given H∞ performance level for the networked LFC system in the presence of multiple cyber-attacks and multi-rate sampling. Finally, the effectiveness of the proposed method is verified through an example of an interconnected power system.

Study on the influence of distributed photovoltaic access grid on voltage quality based on virtual synchronous control strategy

Study on the influence of distributed photovoltaic access grid on voltage quality based on virtual synchronous control strategy

Effect of two different estrus synchronization protocols on pregnancy rate in Blonde D'aquitaine cattle breed reared in Bulgaria

In the study, two protocols for synchronization of estrus and ovulation in seventeen Blonde d’Aquitaine cows reared in Bulgaria are presented. The animals were similar in age (5-6 years), physiological status (non-pregnant with weaned calves, more than 210 days post-calving), and body condition score (average 5 on a 9-point scale). The experiment was conducted on a beef cattle farm near the Danube River at the end of the grazing season. The objective was to investigate the pregnancy rates under different estrus synchronization schemes. Two synchronization schemes with artificial insemination (FTAI – 72 hours) at fixed time were applied. The schemes were based on prostaglandin F2 alpha (PGF2α) and Gonadotropin-Releasing Hormone (GnRH), with one of them using а Progesterone Releasing Intravaginal Device Delta - PRID DELTA. After executing the two protocols, 47.92 ± 12.34% of the Blonde d’Aquitaine cows were confirmed to be pregnant. In the synchronization protocol using PRID DELTA 62.50 ± 17.87% of inseminated cows were pregnant. In the protocol without the device, 33.33 ± 16.94% of inseminated cows were confirmed to be pregnant. Keywords: beef cattle, estrus synchronization, PRID-Synchprotocol

The Resampling Methods Direct Sequence Spread Spectrum Signal’s Demodulator Implementation

Relevance. The direct spread spectrum signals are widely used in navigation and communication systems recently. These signals prevail in modern satellite navigation systems and are used in various communication systems with code division multiplexing in particularly. In this regard, the tasks of building direct spread spectrum signals’ demodulators have the key importance. Mach importance in the construction of demodulators is the problem chip rate variability.The purpose of the study is to propose a demodulator structure focused on solving this problem.Methods. The research is based on computer modeling methods.Decision. The paper proposes an approach to the construction of the direct spread spectrum signal’s demodulators based on modern methods of digital signal processing. It is shown that the main advantage of the proposed approach is the possibility of rebuilding the variable chip rate demodulators. Based on the results obtained, a scheme for the direct spread spectrum signals demodulator using resampling methods is proposed. Resampling, in turn, is implemented on the basis of polynomial interpolation using Lagrange polynomials. The structure of the resampler is proposed, similar to the structure of an interpolating filter with a finite impulse response. The presented simulation results show the effectiveness of the proposed approach.Novelty. It seems that the currently common methods of implementing direct spread spectrum signal in terms of delay synchronization do not sufficiently meet modern requirements. The implementation of delay synchronization schemes based on resampling is practically not discussed in well-known works. At the same time, modern methods and devices of digital signal processing make it possible to ensure an effective hardware implementation of the scheme in question. In this context, the approach proposed in the paper to the construction of demodulators seems to be very relevant.Significance. The results of the work can be used in the construction with direct spread spectrum signals’ demodulators for a wide range of communication and navigation systems. The synchronous sampling structure proposed in this paper is very promising, especially for variable chip rate demodulators.

Proteomic and phosphoproteomic analyses reveal that TORC1 is reactivated by pheromone signaling during sexual reproduction in fission yeast.

Starvation, which is associated with inactivation of the growth-promoting TOR complex 1 (TORC1), is a strong environmental signal for cell differentiation. In the fission yeast Schizosaccharomyces pombe, nitrogen starvation has distinct physiological consequences depending on the presence of mating partners. In their absence, cells enter quiescence, and TORC1 inactivation prolongs their life. In presence of compatible mates, TORC1 inactivation is essential for sexual differentiation. Gametes engage in paracrine pheromone signaling, grow towards each other, fuse to form the diploid zygote, and form resistant, haploid spore progenies. To understand the signaling changes in the proteome and phospho-proteome during sexual reproduction, we developed cell synchronization strategies and present (phospho-)proteomic data sets that dissect pheromone from starvation signals over the sexual differentiation and cell-cell fusion processes. Unexpectedly, these data sets reveal phosphorylation of ribosomal protein S6 during sexual development, which we establish requires TORC1 activity. We demonstrate that TORC1 is re-activated by pheromone signaling, in a manner that does not require autophagy. Mutants with low TORC1 re-activation exhibit compromised mating and poorly viable spores. Thus, while inactivated to initiate the mating process, TORC1 is reactivated by pheromone signaling in starved cells to support sexual reproduction.

Pulse Modulated Neural Nets with Adaptive Temporal Windows for Enhanced Video Perception

A key challenge in modern artificial intelligence is the limited awareness of temporal dynamics. This is especially evident in AI's struggles with video animation and interpreting sequential frames or time-dependent data. This paper presents a new method for modulating neuron spikes to synchronize with incoming frames, addressing the temporal limitations of voltage AI models. This approach involves a specialized class of neuron, similar to Wolfgang Maass's liquid state machine concept. However, our model differs significantly in its synchronization strategy. Neurons are synchronized with frame import, incorporating a flexible time window that enables spike modulation ranging from 1 to 1024 spikes per frame. This adaptability is crucial for accurately processing and interpreting time-based data. The main focus of this paper is to explore the operational principles of these specialized neurons. While the wiring and architectural design of these neurons will be discussed in a future article, this paper aims to establish the foundational understanding of how these neurons function individually and in response to temporal data inputs. By synchronizing neuron spikes with frame inputs and allowing for variable spike modulation, this method aims to enhance AI's ability to handle time-based data. The proposed neuron model represents a step towards more advanced and temporally aware AI systems, potentially unlocking new capabilities in video animation and other time-sensitive applications.

Time transfer and clock synchronization with ghost frequency comb

We report an experimental demonstration of a time transfer and distant clock synchronization scheme based on what we have labeled as a ghost frequency comb, observed from the nonlocal correlation measurements of a laser beam. Unlike a conventional frequency comb, the laser beam used in this work does not consist of a pulse train but instead it is in a continuous-wave operation. The laser beam, consisting of half a million longitudinal cavity modes from a fiber ring laser, is split into two beams, each sent to a distant observer. In their local measurements, both observers observe constant intensity with no pulse structure present. Surprisingly, a pulse train of comb-like, ultra-narrow peaks is observed from their nonlocal correlation function measurement. This observation makes an important contribution to the field of precision spectroscopy, as we show in optical correlation-based nonlocal timing and positioning.

A Novel Synchronization Strategy for Distributed Energy Resources in Weak Grids Using Remote Strong Grid Sensing

This paper proposes a novel strategy for the current injection-based control of distributed energy resources connected to weak grids via a voltage source converter. The current injection controller is no longer synchronized with the point of common coupling but with the strong grid point voltage. The strong grid synchronization control strategy improves the output dynamics of the voltage source converter and recovery after faults in weak grids. The phase difference between the voltage source converter and the strong grid voltages caused by the long power lines does not affect the power control. Furthermore, a time delay-compensation method is proposed which tolerates the communication time delay introduced by the transmission of the synchronization signal from the strong grid point. The performance of the proposed control strategy is verified in detail using MATLAB 2023b simulations and real-time digital simulations on a medium voltage model and also validated in an experiment on a low-voltage grid-feeding inverter setup.

Phase-locked loop based synchronization schemes for three-phase unbalanced and distorted grid: a review

The rapidly growing dispersion of distributed generation systems into the utility grid needs appropriate control techniques to stay interconnected even under abnormal and distorted grid conditions to ensure the overall grid stability. To avoid the loss of renewable energy sources (RES) based power generation, the disintegration of RES with respect to synchronization issues must be prohibited for efficient operation. RES control highly relies on the synchronization technique as it is faster and accurate enough to detect the utility grid variables in terms of amplitude, phase, and frequency. Mostly, the phase-locked loop (PLL) synchronization schemes are utilized for control of RES and monitoring of grid voltage. The dynamics of the grid side converter (GSC) is directly influenced by the performance and design criteria of the PLLs. This paper proposes an overall review of the performances of three phase PLL based grid synchronization methods under diverse weak grid conditions.

A Direct-Digital 40 μA 100 kb/s Intracardiac Communication Receiver with 250 μs Startup Time for Low Duty-Cycle Leadless Pacemaker Synchronization.

The first commercial dual-chamber leadless pacemaker (LLPM) was introduced recently. The system combines two separate implants situated in the right atrium and the right ventricle of the heart. Implant synchronization is accomplished with conductive intracardiac communication (CIC) using the myocardium and blood as transmission channel. Successful implant synchronization of this dual-chamber LLPM has been demonstrated. However, the continuously active synchronization transceivers, consuming about 800 nA, cause a 25-45% reduction in the projected device longevity. This work proposes an alternative strategy for power-optimized LLPM synchronization, which is based on synchronous duty-cycling of the transceivers and direct-digital CIC (DD-CIC). In line with this strategy, a novel low-power DD-CIC receiver for short-packet communication based on Manchester-encoded data and with fast startup time is presented. The circuit was fabricated in 180 nm CMOS technology and analyzed with respect to sensitivity, current consumption and startup time under highly duty-cycled operation. The receiver achieves a sensitivity of 81.6±7.4 μV at a data rate of 100 kb/s, with an active current consumption of 39.1±0.6 μA and a startup time below 250 μs. Operating the receiver as specified by the proposed LLPM synchronization strategy reduces the current consumption to a measured average value of 73 nA. In conclusion, this work suggests synchronous duty-cycling for CIC-based implant synchronization as a promising concept to severely reduce the current consumption of contemporary dual-chamber LLPMs. Consequently, device longevity may be increased significantly, potentially reducing the frequency of costly and complication-prone re-interventions.

Separable synchronous auxiliary model adaptive momentum estimation strategy for a time-varying system with colored noise from on-line measurements.

The primary focus of this article is to explore parameter estimation for time-varying systems affected by colored noise. Based on the attributes of the time-varying system with colored noise under investigation, the original system is separated and two different subsystems are reconstructed. To address the influence of the hidden variables in the system and the time-varying noise signal, we introduce auxiliary models into the reconstructed systems to achieve the separation and synchronization estimation of the time-varying parameters within the system. With the aim of achieving high-precision performance in estimating the time-varying parameters, a separable synchronous auxiliary model adaptive momentum algorithm is presented by introducing bias correction to the momentum and gradient square term and online parameter estimation is implemented. The proposed algorithm is used for estimating the time-varying output error moving average model to verify the performance. The results of simulation experiments illustrate the efficacy of the proposed method for estimating the time-varying system with colored noise. Additionally, the proposed algorithm is extended to a kind of direct current (DC) motor modeling parameter identification problem and shows good tracking performance.

An effective path planning approach for robot welding considering redundant kinematics

Robot welding with redundant kinematics demands precise coordination of the welding path and redundant axis motion for stable operation. This paper introduces an effective G3 continuous path planning approach for a 6-DOF friction stir welding robot, integrating redundant axis motion to enhance welding stability and quality. The method encompasses a two-pronged strategy: a five-axis path corner smoothing technique and a motion synchronization strategy. Initially, a robust toolpath preprocessing algorithm is presented to mitigate curvature extremities of the inserted smoothing curves within predefined error limits. Subsequently, leveraging G3 continuity criteria, a B-spline-based smoothing method is advanced for refining tool position and orientation paths, with an analytical determination of spline control points facilitated by an explicit smoothing error expression. An effective motion synchronization technique is then proposed, which formulates the tool position, tool orientation, and redundant axis path as explicit functions of the position path arc length. The effectiveness of the proposed method is demonstrated through simulations and experiments on a robot welding platform, with the integration of a jerk-continuous feedrate profile for smooth motion execution. The findings indicate a significant improvement in robotic welding quality by integrating the proposed path planning method with existing workpiece posture optimization techniques.

Advanced Hierarchical Lithiophilic Scaffold Design to Facilitate Synchronous Deposition for Dendrite‐Free Lithium Metal Batteries

AbstractLocalized deposition behavior tends to induce the growth of lithium dendrite and hinder the the full utilization of lithium storage space, significantly impeding the practical application of 3D conductive hosts. Here, a novel synchronous deposition mode is proposed for the first time through hierarchical structure design of 3D Li host. The top‐down gradually enhanced lithiophilicity and conductivity of 3D scaffold provide sufficient driving force for Li+ to migrate downward, promoting synchronous Li deposition within the entire space of the host. Notably, the novel deposition mode has been theoretically and experimentally validated through finite element simulation and in situ optical microscopy, respectively. The meticulously designed strategy not only maximizes the utilization of the entire 3D scaffold space but also prevents the formation of Li dendrites under high current rate. Consequently, the symmetric Li//Li cell exhibits a long‐term cycling lifespan over 3700 h with a low overpotential of 15.6 mV, together with a Coulombic efficiency as high as 99.5% over 300 cycles at 3 mA cm−2. The full cell paired with LiFePO4 cathode demonstrates a cycling lifespan of 1000 cycles with a capacity retention rate of 91.6%. The proposed synchronous deposition strategy opens up a new paradigm for the design and construction of 3D hosts for dendrite‐free Li metal anode.

GSyncCode: Geometry Synchronous Hidden Code for One-step Photography Decoding

Invisible hyperlinks and hidden barcodes have recently emerged as a hot topic in offline-to-online messaging, where an invisible message or barcode is embedded in an image and can be decoded via camera shooting. Current schemes involve a two-step decoding process: starting with vertex localization of the embedded region to correct the perspective distortion introduced by shooting, followed by decoding the message from the corrected region. However, vertex localization can be complex and time-consuming, which affects the efficiency and accuracy of message decoding. To address this issue, this paper proposes a geometry synchronous decoding scheme called GSyncCode, allowing for one-step extraction of a Data Matrix code from the photograph. Instead of correction before decoding, GSyncCode directly decodes a geometry-transformed Data Matrix that is synchronized with the embedded region. A barcode scanner is then used to efficiently retrieve messages. We design a Haar-transform based encoder HaarUNet and a HaarLoss visual function to select the key component of the Data Matrix for embedding. They improve the visual quality of the embedded image by reducing redundant embedding signals. Extensive simulated and real-world experiments demonstrate the superiority of GSyncCode in both decoding efficiency and accuracy. Our codes are published at: https://github.com/zcx-language/GSyncCode.