Synchronization Method Research Articles

Synchronization and coordination control based on enhanced deviation coupling for multi-motor rigid connection systems

Abstract The operational performances of the conventional controlled multi-motor drive systems are affected by the parameters of the motor, sudden load changes, and external disturbances. These factors may cause issues such as motor speed loss and torque imbalance, with severe cases potentially resulting in motor shaft fractures. In this paper, an enhanced deviation coupling-based synchronization and coordination control method is proposed for multi-motor rigid connection systems. The monomer and gear structure of the induction motor are modeled, respectively, and the transfer functions are given to analyze the factors that affect speed unsynchrony and torque uncoordination for the multi-motor systems. The inherent shortcomings of simple deviation coupling control are clarified, which makes it difficult to achieve the speed synchronization and torque balance of the multi-motor systems. An enhanced deviation coupling control method that simultaneously compensates for speed and torque is designed, and its stability is analyzed. Compared with the deviation coupling control method, the experimental results show that the proposed control method effectively reduces the speed synchronization errors and suppresses the torque output fluctuation. The control system has better performance of real-time and robustness.

Dual-wavelength synchronous control method for liquid crystal optical phased array

The liquid crystal optical phased array (LCOPA), as a key beam steering device, has gained increasing significance in the field of space laser communication. With the rapid advancement of space laser communication technology, the demand for precise synchronous control of multi-wavelength beams has significantly increased, particularly in ensuring reliable communication links through synchronized control of signal and beacon beams. The signal beam is primarily utilized for data transmission, while the beacon beam is responsible for path calibration and real-time tracking. However, due to the limitations of natural dispersion effects, conventional LCOPA control methods struggle to achieve synchronized manipulation of beams at different wavelengths, resulting in error accumulation and response delays in communication links, thereby compromising the accuracy and efficiency of information transmission. To address this challenge, this study proposes and validates a dual-wavelength synchronous control method based on LCOPA. The method establishes a phase optimization principle centered on minimizing the least-squares error of complex amplitudes and expands the phase modulation capability of LCOPA hardware, thereby overcoming the natural dispersion governed by the grating equation. Simulation and experimental results demonstrate that this method achieves exceptionally high beam pointing accuracy, meeting the demands of high-precision information transmission in multi-wavelength laser communication. This study provides an innovative technical pathway for the application of LCOPA in multi-wavelength laser communication and establishes a solid theoretical foundation for future experimental research on multi-wavelength control.

A Low-Cost Evaluation Tool for Synchronization Methods in Three-Phase Power Systems

The use of renewable energy sources (RESs) together with energy storage systems (ESSs) allows for smoothing power variations, thus improving power backup capabilities and power quality in the electric power grid. These applications require power converters to transfer energy between the renewable generator or energy storage and the power grid. In any case, the control algorithm of the power converter requires the synchronization method to provide a correct estimation of the instantaneous voltage of the power grid. This work provides engineers and researchers with an accessible platform at a low cost (less than USD 100) and a methodology for the experimental validation of digital synchronization algorithms as a step before their implementation in grid-connected equipment. The methodology evaluates the performance of the digital algorithms when there are variations in amplitude, frequency, phase, and harmonic content in the emulated three-phase power grid, as well as the execution times (tex), while a digital platform emulates the electrical signals and generates reference signals for the evaluation. To illustrate this proposal, two synchronization algorithms—SRF-PLL and DSOGI-PLL with a low-pass filter—are implemented in a digital controller and tested. The evaluation tool confirms the algorithms’ performance and shows that the execution time of DSOGI-PLL is 91% longer than that of SRF-PLL, which is well known in the literature.

Presetting-time complete synchronization of two Lorenz systems with applications into nonlinear PMSMs and Hindmarsh-Rose neuron models

Abstract This paper begins by examining the presetting-time synchronization (PtS) of two nonlinear Lorenz systems and subsequently applies these findings to synchronize the permanent magnet synchronous motors (PMSMs) and Hindmarsh-Rose neuron models. Unlike conventional finite-time synchronization (FtS) or fixed-time synchronization (FxS) methods, the upper bound estimation of convergence time (UBECT) in this study can be predefined as a constant, unaffected by initial conditions or control parameters. Furthermore, the control schemes developed here are free from chattering, as they avoid using traditional discontinuous signum and absolute value functions. Through classical Lyapunov stability analysis, sufficient conditions are derived to ensure PtS between nonlinear Lorenz systems, PMSMs, and Hindmarsh-Rose neuron models. Lastly, numerical simulations are conducted to confirm the accuracy and efficiency of the theoretical findings, with comparisons and perturbation analyses also included.

A safe and robust in-situ polymerized cementitious electrolyte coupled with NiCo2S4@CuCo2S4 electrode for superior load-bearing integrated electrochemical capacitor.

Load bearing/energy storage integrated devices (LEIDs) featuring cementitious electrolytes have become ideal for large-scale energy storage. Nevertheless, the progression of LEIDs is still in its nascent phase and considerable endeavors concerning cementitious electrolytes and electrode materials are necessary to further boost the charge storage ability. Here, we propose a facile synchronous reaction method for preparing sodium acrylate (SA)-based in-situ polymerized cementitious electrolyte. The soft polymer network and hard cement matrix are interwoven together. The resulting cementitious electrolyte not only exhibits improved mechanical properties (flexural strength of 14.7MPa and compressive strength of 44.7MPa), but also possesses enhanced ionic conductivity (26.7mScm-1). Moreover, a core-shell NiCo2S4@CuCo2S4/NF heterostructure is synthesized on nickel foam (NF) substrate by hydrothermal assisted electrodeposition techniques, which showcases a remarkable capacitance of 5626.6mFcm-2 at 1mAcm-2. As a proof, with integrated merits of the optimal cementitious electrolyte and NiCo2S4@CuCo2S4/NF electrode, the as-built LEID demonstrates a high energy density of 138.5μWhcm-2 at 0.75mWcm-2 and a cycling durability of 90.7% after 8000 cycles, showing good practicability in lighting light-emitting diodes (LEDs) or driving a thermal hygrometer. Notably, the LEID can endure external forces without distinctly sacrificing electrochemical properties. This work provides insight into developing novel cementitious electrolytes and electrode materials toward superior LEIDs.

An improved carrier-phase-based method for precise time synchronization using the observations from the China Space Station-ground synchronization system

The development of precise time synchronization technology is key to the effective application of time–frequency standards. It will significantly promote the application of precise time–frequency standards in the areas such as Positioning, Navigation, and Timing, lunar navigation, and cutting-edge fundamental physics research. This study presents an improved carrier-phase-based method for time synchronization, which was demonstrated through both laboratory and satellite-ground experiments via the China Space Station (CSS)-ground synchronization system. Initial laboratory experiments confirmed the system’s stability, achieving picosecond-level accuracy, highlighting the robustness of the method in controlled environments. Then, preliminary satellite-to-ground synchronization experiments were conducted using the CSS and ground stations, validating the effectiveness of the carrier-phase-based method. The time synchronization accuracy reached the picosecond-level, significantly surpassing traditional pseudocode techniques, which typically achieve sub-nanosecond level accuracy. Additionally, the Allan Deviation results indicated an improvement in stability by about an order of magnitude compared to traditional pseudocode-based methods. This demonstrates that the carrier-phase-based method can effectively mitigate common sources of system errors and enhance time synchronization capabilities. Therefore, this method can provide an effective technical reference for future applications requiring higher precision in time synchronization.

Synchronous multi-wavelength interferometric method for measuring aspherical surface profile

Synchronous multi-wavelength interferometric method for measuring aspherical surface profile

Pharmacy students' perspective on remote flipped classrooms in Malaysia: a qualitative study.

This study aimed to explore pharmacy students' perceptions of remote flipped classrooms in Malaysia, focusing on their learning experiences and identifying areas for potential improvement to inform future educational strategies. A qualitative approach was employed, utilizing inductive thematic analysis. Twenty Bachelor of Pharmacy students (18 women, 2 men; age range, 19-24 years) from Monash University participated in 8 focus group discussions over 2 rounds during the coronavirus disease 2019 pandemic (2020-2021). Participants were recruited via convenience sampling. The focus group discussions, led by experienced academics, were conducted in English via Zoom, recorded, and transcribed for analysis using NVivo. Themes were identified through emergent coding and iterative discussions to ensure thematic saturation. Five major themes emerged: flexibility, communication, technological challenges, skill-based learning challenges, and time-based effects. Students appreciated the flexibility of accessing and reviewing pre-class materials at their convenience. Increased engagement through anonymous question submission was noted, yet communication difficulties and lack of non-verbal cues in remote workshops were significant drawbacks. Technological issues, such as internet connectivity problems, hindered learning, especially during assessments. Skill-based learning faced challenges in remote settings, including lab activities and clinical examinations. Additionally, prolonged remote learning led to feelings of isolation, fatigue, and a desire to return to in-person interactions. Remote flipped classrooms offer flexibility and engagement benefits but present notable challenges related to communication, technology, and skill-based learning. To improve remote education, institutions should integrate robust technological support, enhance communication strategies, and incorporate virtual simulations for practical skills. Balancing asynchronous and synchronous methods while addressing academic success and socioemotional wellness is essential for effective remote learning environments.

Synchronization in Public Transportation: A Review of Challenges and Techniques

Performing synchronization in public transport is one of the most challenging tasks that transport managers perform when organizing the processes of passenger servicing. Many variables characterizing existing public transport lines should be considered in the final timetable; in addition, the complexity of the transportation system, the variability in transport demand, and the stochasticity of the servicing process both in time and space have a significant influence on the result of synchronization. The synchronization problem in real-world applications does not have an exact solution, so in practice, a variety of techniques were developed to achieve a rational solution in a reasonable time. In our paper, we classify existing approaches to solving the problem of public transport synchronization, describe the essence of the most promising methods, and study their popularity based on the most recent scientific publications. As the result of our research, we show the most promising directions for the future development of synchronization methods and their application in public transportation.

Enhanced spectral resolution in mid-infrared dual-comb spectroscopy via synchronous offset frequency tuning.

Mid-infrared dual-comb spectroscopy offers significant advantages by combining the high sensitivity of mid-infrared spectroscopy with the high spectral resolution and rapid acquisition of the dual-comb method. However, its effective resolution, constrained by the inherent comb line spacing, hinders its ability to resolve narrow absorption features, common in critical applications such as sub-Doppler spectroscopy, low-pressure gas analysis, and construction of the atmospheric profile. To address this challenge, we present a synchronous offset frequency tuning method for the mid-infrared dual-comb system to improve effective resolution far beyond comb line spacing. In our system, the mid-infrared dual-comb source is generated from a near-infrared dual-comb source and a continuous-wave pump laser via difference frequency generation in a single periodically poled lithium niobate bulk. By adjusting the phase-lock frequency of the pump laser to one of the near-infrared combs, we synchronously tune the offset frequencies of both mid-infrared combs without changing the near-infrared dual-comb source. We demonstrated that this method enabled the high resolution of overlapped spectral lines of ethane around 3000 cm-1, achieving a uniform spectral sampling interval of 10 MHz in the interleaved spectrum and a 25-fold enhancement in effective resolution. This approach allows for sub-MHz spectral resolution in mid-infrared dual-comb spectroscopy without any modifications to the data acquisition system, offering possibilities for high-precision spectral analysis.

A two‐channel data and power synchronous transmission method for SRG‐integrated power networks through piecewise composite modulation

AbstractReliable communication is key to achieving remote control, status monitoring, and early fault detection in SRG‐integrated power networks. This paper proposes a novel piecewise composite modulation method to simultaneously modulate data and power during the excitation and power generation stages in each phase of an SRG system. By adopting a frequency‐shift keying modulation strategy, two‐channel data can be modulated and injected into the bus voltage as voltage ripples, allowing for more efficient use of the bus voltage frequency band. Welch's algorithm‐based power spectrum method is innovatively employed to demodulate the transmitted data on the SRG's output bus. Experimental results confirm the feasibility of the proposed data and power synchronous transmission (DPST) strategy, which shows significant potential in SRG‐integrated power networks.

Tectonic implications of raised Quaternary relative sea‐level indicators along the NE border of the Campania Plain (southern Italy)

AbstractTectonically raised paleoshorelines have been recently identified along the southern fault scarps of the Mt. Fellino and Roccarainola horst blocks, which are part of the northeastern border of the Campania Plain coastal basin (southern Apennines, Italy). Such horst blocks are bounded to the south by the Polvica Fault, a roughly E‐W trending normal fault. The sequence of uplifted paleoshorelines has been studied in detail by integrating geomorphological, structural and stratigraphical analyses to assess the Quaternary uplift of the Mt. Fellino and Roccarainola horst blocks. Yet, the staircase of paleoshorelines is still not chronologically well constrained.Aimed at constraining the uplift history of Mt. Fellino and Roccarainola horst blocks and the rate of activity of the Polvica fault, in this study, we integrate former knowledge on paleoshorelines with a geomorphological analysis to map erosional terraces, that we interpret as remnants of shore platforms. We apply the synchronous correlation method, driven by new and a former 230Th/234U dating of calcite veins cutting marine sands, to infer the age of the paleoshorelines and terraces. Based on the synchronous correlation, the mapped paleoshorelines and terraces are correlated with sea‐level peaks of the late Early to Late Pleistocene. In particular, the paleoshorelines along the Mt. Fellino ridge are correlated with the Marine Isotope Stage (MIS) 7e and 9c or 11, while the oldest terrace is correlated with the sea‐level peak of 980 ka. Using inferred paleoshorelines ages, we estimate the uplift rate of the Polvica Fault footwall. The uplift rate varies from c. 0.2 mm/yr close to the western fault tip up to c. 0.5–0.6 mm/yr in the East, in the Roccarainola block. We combine surface evidence with subsurface data from a shallow well to constrain the vertical throw of the Polvica Fault. A mean fault throw rate of c. 0.4 mm/yr in the last c. 1 Ma is estimated for the central part of the PF. Assuming that the Polvica Fault is still active, we estimate the maximum expected earthquake by means of empirical relationship and obtain a Mw ~ 6.2 value and recurrence interval value of c. 1,200 yr. Historical seismicity activity of the PF has not been acknowledged to date. However, our results raise the crucial question of an in‐depth assessment of the seismic hazard for the densely populated Campania Plain.

ADALINE-based synchronous detection for enhanced shunt APF performance

Power quality issues caused by current harmonics from nonlinear and unbalanced loads are a growing concern. This paper presents a novel control strategy for four-wire shunt active power filters (SAPF) that surpasses existing conventional methods in mitigating harmonics and power factor correction. The strategy employs an improved synchronous detection method (SDM) enhanced by an adaptive linear neural network (ADALINE) trained using the least mean square (LMS) algorithm. This approach accurately estimates harmonic frequencies, enabling the SAPF to generate precise compensation currents. The effectiveness of the proposed method is validated through MATLAB-Simulink simulations under balanced supply conditions, encompassing diverse load scenarios. These simulation results are compared with those obtained using instantaneous power theory (IPT). They demonstrate the ability of the proposed method to achieve excellent harmonic identification and elimination, to comply with IEEE 519 harmonic limits, to ensure sinusoidal and balanced line currents, and to compensate for reactive power and neutral current. Furthermore, its simple architecture and noise robustness make it a promising solution for enhancing power quality.

A Low-Complexity Sensing-Aided Timing Synchronization Method for UAV-Assisted OFDM Systems

A Low-Complexity Sensing-Aided Timing Synchronization Method for UAV-Assisted OFDM Systems

Methods for Detecting Phosphorylated Proteins and Observing Intracellular Localization During Mitosis.

This protocol describes the detection of phosphorylated proteins within cells and the identification of their intracellular localization, with a particular focus on mitotic cells. While the detection of phosphorylated proteins can be achieved using radioactive labeling with 32Pi, this method presents experimental challenges due to the requirement for radioisotopes. Alternatively, detection using phosphorylation-specific antibodies is a potent method; however, it necessitates the identification of phosphorylation sites and further requires the generation of antibodies targeting these sites, making it effective only for thoroughly analyzed phosphorylations. Here, we outline a convenient method for detecting intracellular phosphorylation using the Phos-tag technique. Additionally, we discuss the establishment of inducible stable cell lines using lentivirus, synchronization methods for cells in the mitotic phase using thymidine and nocodazole, as well as some tips for immunoprecipitation, Western blotting, and immunostaining from mitotic cells.

A Multi Parameter Synchronous Identification Method for Stiffness and Damping of Single Fixed Clamp Based on Pareto Algorithm

As a composite structure, the single fixed clamp (SFC) is an important supporting component of the aeroengine piping system. The dynamic parameters (stiffness and damping) of SFC have significant differences in bolt direction and opening direction. Accurately identifying the dynamic parameters of an SFC in both directions is of great significance for the study of pipeline system dynamics. At present, there is very little research on the identification of dynamic parameters for such SFC. Therefore, an SFC-straight pipe structure for identifying the dynamic parameters of an SFC is proposed in this paper. In this structure, one end of the straight pipe is completely fixed, and the other end is supported by an SFC. This structure can better reflect the working state of the SFC. A dynamic model of this structure is established based on the finite element method for parameter identification of SFC. In the finite element model (FEM), the constraint effect of the SFC is simplified into two identical spring-damping groups. Considering the structural asymmetry, spring and damping parameters for bolt direction and opening direction are separately set in each spring damping group. Next, based on the Pareto multi-objective genetic algorithm, an identification algorithm and procedure for the stiffness and damping of the SFC using modal test data as input parameters are proposed. Through experimental testing, parameter identification is carried out for DK8 type SFC, and a straight pipe experimental structure completely supported by two SFCs is constructed to verify the correctness of the identification results.

Experimental Study of the Applicability of Simple Microcontrollers for Implementing the Microgrid Decentralized Synchronization Method in the Electrical Network

Currently, on the basis of local power supply systems with small distributed generation, active networks called Microgrid are formed. Such networks can be adapted to work both independently and in parallel with the external network. In such networks, it is difficult to synchronize sources. The purpose of this paper is to study the features of implementing the Microgrid decentralized synchronization method on simple controllers and assess the sufficiency of their technical capabilities. Atmega 328P – Arduino NANO and UNO were used as microcontrollers.

On novel Hexa-compound combination synchronization over nineteen n-dimensional category-B chaotic systems and electronic circuit schematic

Abstract Synchronization of chaotic models involving multiple drives and responses has numerous practical applications in cryptography and information processing. Existing research on synchronizing multiple chaotic systems is currently limited to twelve components. This study introduces a novel higher-order synchronization method, hexa compound combination, that synchronizes an assembly of nineteen n-dimensional chaotic models. Well-known synchronization methods, such as double compound, triple compound, and quad compound, serve as particular instances of this new strategy. Thus, our research significantly advances the understanding of multi-leveled chaos synchronization. In addition, we also present a non-uniformly conservative system classified into a rare category B, analyze its dynamic properties, and utilize it for achieving the proposed synchronization. Numerical results are provided through graphical representations to illustrate the efficacy of the new synchronization approach by comparing it with other techniques. Furthermore, we emulate the corresponding virtual schematic circuit of the newly designed system to evaluate its real-world applicability and utility.

Digital Twin-Based Production-Logistics Synchronization System for Satellite Mass Assembly Shop-Floor

AbstractIn recent years, the rapid development of large-scale satellite constellations has challenged the mass production capabilities of satellite manufacturers. Assembly is the last and critical phase of satellite production. Achieving satellite mass assembly is the key to realizing satellite mass production. To this end, satellite manufacturers are working to construct the satellite mass assembly shop-floor (SMAS) to enable moving assembly. However, there is still a lack of a modularized manufacturing system oriented to flexible production for SMAS, as well as disturbance detection methods and production-logistics synchronization methods to deal with various disturbances. Therefore, this paper proposes a digital twin-based production-logistics synchronization system (DT-PLSS) for SMAS. The framework of DT-PLSS is introduced first. In this framework, DT-PLSS can achieve modular construction, as well as distributed management and control. Based on the proposed framework, the construction methods of resource level digital twin (DT), workstation level DT, and shop-floor level DT in SMAS are discussed. The DT-based disturbance detection method for SMAS is presented, aiming to detect or predict different types of disturbances and to analyze the effect of disturbances. Then, a DT enhanced production-logistics synchronization mechanism for SMAS is proposed. With this mechanism, the logistics distribution in the dynamic shop-floor environment and production-logistics synchronization under various disturbances can be realized. Finally, a case study in a real SMAS verifies the feasibility and effectiveness of the proposed system and methods. This research proposes a practical framework and system which could realize disturbance detection, logistics distribution, and the production-logistics synchronization in complex SMAS scenario effectively.

A Conceptual Framework for Open Distance Learning of Economics in Malaysia

The aim of the paper is to propose a comprehensive conceptual framework of open and distance learning (ODL) for economics courses to enhance the effectiveness and accessibility of economics education. The rise of ODL, fueled by advances in digital technology, has significantly transformed higher education, providing flexible learning opportunities that transcend geographical limitations. However, teaching economics in an ODL environment presents unique challenges, particularly in maintaining student engagement and delivering complex theoretical content. This research draws from literature review and key concepts to conceptualise a model for ODL in economics undergraduate teaching and learning. The proposed framework emphasizes the integration of synchronous and asynchronous learning methods, the use of Learning Management Systems (LMS) and the incorporation of interactive technologies such as virtual and augmented reality to facilitate an engaging and effective learning experience. Additionally, the framework addresses curriculum design, student engagement and assessment strategies, proposing a balanced approach that combines traditional teaching methods with innovative digital tools. By focusing on the goal of teaching students to "think like an economist," this framework provides a structured approach to ODL that enhances both the delivery and the reception of economic education. The paper’s recommendations are to modernize the curriculum, strengthen institutional support and optimize the use of digital tools in the teaching of macroeconomics. This research contributes to the broader discourse on the potential of ODL to transform economics education in Malaysia and beyond.