Synchronization Method Research Articles

Feedback projection synchronization of discrete chaotic systems and its application to speech encryption

Abstract Chaotic systems are widely used in secure communication due to their sensitivity to initial values, unpredictability, and complex motion trajectories. In this paper, we study the encryption method of chaotic synchronization and introduce a scaling factor based on traditional feedback control synchronization to achieve more accurate projection synchronization. The effectiveness and robustness of the method in chaotic systems are verified through theoretical proofs and numerical simulations. A chaotic masked speech encryption system utilizing bit similarity is designed; the structural similarity index (SSIM) of the decrypted signal with the original signal is as high as 0.992866, while the SSIM value of the encrypted signal with the original signal is only 0.000030, proving the efficiency and security of the encryption process. Additionally, we analyzed the data transmission process of the encryption system. The fusion of the control signal and the encryption sequence into one transmission sequence in the channel not only saves hardware and software design resources but also reduces inter-channel interference and conflict, improving the reliability and stability of the transmission. Experimental results show that the system performs well in terms of data transmission security and anti-interference capability.

Accuracy study for over-the-air frequency synchronization of continuous wave signals

Abstract Future communication and radar sensing systems will require synchronization methods which are more versatile in terms of the systems involved in the synchronization process. We present an over-the-air frequency synchronization algorithm based on the standard and the generalized Kuramoto model which uses continuous wave (CW) signals. In contrast to other approaches, all nodes of the network participate equally, and synchronization can even be achieved in presence of a non-cooperative node. By changing the parameters of the radar or by modifying the synchronization algorithm, synchronization accuracy can be adjusted as well. All claims are supported by measurements conducted with CW radars. It will be demonstrated that our algorithm enables synchronization accuracies down to 1.92 ppb and thus could provide sufficient accuracy for velocity measurements on pedestrians.

A synchronization method based on current orthogonal decomposition considering harmonic components for wireless power transfer system

AbstractIn order to improve the wireless power transfer (WPT) system, an active rectifier is commonly used. Synchronization technology is critical for active rectifier. The traditional synchronization method based on zero‐crossing detection (ZCD) is unstable and not suitable for the case with lots of harmonic component in the resonant current. Here, a new synchronization method with harmonic compensation is proposed for the WPT system without the ZCD of the resonant current. A mathematical model is built to analyse and compensate the impact caused by the harmonic on phase angle. Therefore, the proposed method can be applied to the high‐order resonant network like LCC compensated topology where the harmonic component is rich in the resonant current. For verifying the proposed synchronization method, a laboratory prototype is built. The experimental results prove that the system can operate stably with parameter perturbation and different load. The peak transfer efficiency of the system can achieve the 94.5%.

Research on ultrasonic synchronous detection method for material residual stress and thickness

Being limited to the different transmission and reception modes and detection signals of the critical refracted longitudinal wave method for stress measurement and the perpendicular incident echo method for thickness measurement, it is necessary to use different probes and equipments when simultaneously measuring stress and thickness. For this difficulty, the acquisition frequency and the number of bits are taken as the research object to realize the optimization of the echo signal. By combining FEM simulations with Comsol software with experimental research, the effects of probe incidence angle, probe spacing, and temperature on ultrasonic waves are investigated, and the relationship between probe spacing and the stress coefficient of measured component (K) is analyzed. A novel ultrasonic synchronous detection method for residual stress and thickness is proposed. This method is based on an integrated transmit-receive probe with oblique incidence, utilizing critical refracted longitudinal wave (LCR wave) for stress detection and synchronously generated transverse waves for thickness measurement. For the first time, a formula for ultrasonic thickness measurement based on inclined incidence is derived. Using self-developed equipment, ultrasonic testing experiments on step test block and cantilever beam loading device were conducted to verify the accuracy and precision of the proposed synchronous detection method for stress and thickness. This method has significant application prospects in the inspection or online monitoring of pressure vessels concerned with fatigue and corrosion performance.

A Fast Converter Synchronization Speed Method Based on the Frequency Difference on Both Sides of the Grid Connection Point

The challenge of achieving a reliable and safe synchronization process for microgrids under weak communication conditions is a significant issue in distributed grid-connected energy storage. This is also the core motivation of this study. First, the concept of weak communication is introduced, and weak communication conditions are simulated by limiting the number of communications. Additionally, a fast synchronization method based on the frequency difference at the grid connection point is proposed, which allows for the rapid synchronization of converters under weak communication conditions. This method also includes an analysis of the range for key parameters, providing practical and feasible guidance for its real-world application. Finally, the validity of the theory is verified through PSCAD/EMTDC simulations and physical experiments.

Injection locking in DC-driven spintronic vortex oscillators via surface acoustic wave modulation

Control of the microwave signal generated by spin-transfer torque oscillators (STOs) is crucial for their applications in spin wave generation and neuromorphic computing. This study investigates injection locking of a DC-driven vortex STO using surface acoustic waves (SAWs) to enhance the STO’s signal and allow for its synchronization with external inputs. We employ a simplified model based on Thiele’s formalism and highlight the role of vortex deformations in achieving injection locking. Micromagnetic simulations are conducted to validate our theoretical predictions, revealing how the locking bandwidth depends on SAW amplitude, as well as on the amplitude and direction of an applied external field. Our findings are pivotal for advancing experimental research and developing efficient low-power synchronization methods for large-scale STO networks.

Preamble Detection Method for RSS Data Synchronization in WLAN Monitoring

Preamble Detection Method for RSS Data Synchronization in WLAN Monitoring

Load forecasting based on multi-core learning Support Vector Machine (SVM)

Abstract The development of smart grids requires enhanced data integration, robust risk assessment, and dynamic response optimization. In this paper, a multi-core learning Support Vector Machine (SVM) model is presented to improve the accuracy and efficiency of load and photovoltaic output forecasting. The model leverages kernel function optimization and parallel computing frameworks to handle large-scale data efficiently. Additionally, a comprehensive risk assessment system is developed to quantify risks such as overvoltage, undervoltage, line overload, and load loss in distribution networks. An adaptive genetic algorithm-based risk control model is also proposed, optimized in two stages—day-ahead and intra-day—to achieve minimal comprehensive risk through real-time adjustments in distributed power output and electric vehicle charging strategies. Furthermore, an integrated virtual synchronous control online verification method for source-network-load-storage is introduced, enhancing system response speed and control accuracy. These innovations collectively provide a solid theoretical foundation and technical support for the efficient and safe operation of smart grids, addressing the increasing demands of modern energy systems.

Can a zoom class be dialogic? An examination of a virtual English methods class

Purpose Synchronous virtual classes are becoming more common as universities expand access. However, instructors can feel hesitant as they move to a new style of teaching, especially if they are not sure their chosen pedagogy will work with virtual instruction. The purpose of this dialogic analysis is to examine the experiences of a dialogic teacher in a synchronous virtual English methods course. Design/methodology/approach The 75-min methods class met on Zoom twice a week. Class sessions were recorded. Dialogic analysis was used to analyze moments of whole-class discussion to explain what kinds of discussions happened and determine to what extent the class functioned as a dialogic class. Findings Overall, there was more student voice than teacher voice, and students spent over a third of the class in small group discussions. Even though the teacher still took over, and controlled discussions, the overall class maintained dialogic teaching principles. Despite this, the professor felt displaced for three reasons. In addition, some ideas for increasing the dialogic nature of the class are mentioned. Originality/value Synchronous virtual teaching will continue to grow, but as instructors move to that format, they can examine whether their pedagogies match the format. This paper explored one professor’s pedagogy of dialogic teaching and its compatibility with synchronous virtual teaching. This method of self-analysis could work with any pedagogy and could help instructors be successful in a new format.

Phase synthesis method in multi-aperture optical systems based on iterative image processing algorithms

Background. Modern technologies in the field of optics and photonics place high demands on the quality and output power of the radiation source. The fulfillment of these requirements can currently be achieved by creating multi-aperture laser systems with coherent beam addition. The main problem of creating such systems is the development of phase synthesis methods in a multichannel optical system. Aim. In this paper, we consider a phase synchronization method without a reference beam for a coherent addition system with active feedback, which is based on the Gerchberg–Saxton algorithm. This algorithm makes it possible to reconstruct complex field amplitudes in the aperture and focal planes from intensity distributions in these fields. The application of this algorithm for multichannel systems is analyzed and its features, such as the occurrence of stagnation and ambiguity of the solution, are revealed. Methods. Solutions are proposed to eliminate the problem of convergence of the algorithm to side solutions and getting the iterative procedure into the local extremum using global optimization algorithms, methods of reducing the dimension of the problem and the introduction of antisymmetric amplitude modulation. Results. The paper demonstrates the results of phase field reconstruction for a large number of optical sources. For a seven-aperture system, a physical simulation was performed to restore phase information, confirming the results of numerical modeling. Conclusion. The proposed approach is a reasonable alternative to currently existing methods and can be used in the problem of coherent addition in multichannel optical systems.

Telehealth of Infants at Risk During the COVID-19 Pandemic: Physical Therapists’ and Caregiver’s Perceptions and Costs

Aim We aimed to describe telehealth used to detect infants at risk of neurodevelopmental delay and assess the assessors’ and caregivers’ perceptions and costs. Methods This was an observational study in which five physical therapists applied the General Movement Assessment, the neurological exam based on the Hammersmith Infant Neurological Examination, and the Alberta Infant Motor Scale via telehealth in 65 infants at risk of neurologic delay during the COVID-19 pandemic. The perceptions of assessors and caregivers were assessed using a questionnaire. We tabulated the family’s costs (internet access) and the therapist’s expenses (internet access and professional fees). Results In general, assessors felt comfortable and reported good quality of teleassessment. They highlighted the significant effort they and caregivers required for synchronous methods, challenges in clearly guiding caregivers on infant positioning, difficulties in adjusting the camera’s position, and unstable internet connections. Most assessors expressed a willingness to continue using telehealth. Caregivers displayed high satisfaction, and the costs were minimal. Conclusion Teleassessment during the COVID-19 pandemic was feasible, although implementing this method of health service in general clinical practice still requires further scrutiny.

Modeling of Liquefied Natural Gas Cold Power Generation for Access to the Distribution Grid

Cold energy generation is an important part of liquefied natural gas (LNG) cold energy cascade utilization, and existing studies lack a specific descriptive model for LNG cold energy transmission to the AC subgrid. Therefore, this paper proposes a descriptive model for the grid-connected process of cold energy generation at LNG stations. First, the expansion kinetic energy transfer of the intermediate work mass is derived and analyzed in the LNG unipolar Rankine cycle structure, the mathematical relationship between the turbine output mechanical power and the variation in the work mass flow rate and pressure is established, and the variations in the LNG heat exchanger temperature difference, seawater flow rate, and the turbine temperature difference in the cycle system are investigated. Secondly, based on the fifth-order equation of state of the synchronous generator, the expressions of its electromagnetic power, output AC frequency, and voltage were analyzed. Finally, the average equivalent models of the machine-side and grid-side converters are established using a direct-fed grid-connected structure, thus forming a descriptive model of the overall drive process. The ORC model is built in Aspen HYSIS to obtain the time series expression of the torque output of the turbine; based on the ORC output torque, the permanent magnet synchronous generator (PMGSG) as well as the direct-fed grid-connected structure are built in MATLAB/Simulink, and the active power and current outputs of the grid-following-type voltage vector control method and the grid-forming-type power-angle synchronous control method are also verified.

Synchronous flying-around control for uncontrolled tumbling spacecraft

The problem of synchronous flying-around control for uncontrolled tumbling target spacecraft is investigated in the paper. Firstly, the relative motion equations of the chaser and the target is established based on the line of sight (LOS) coordinate system, and the scenario of the chaser flying-around uncontrolled tumbling target is analyzed. Secondly, the attitude motion model of the uncontrolled tumbling target is established, and the attitude of the target is described by the Modified Rodriguez Parameters (MRPs). The synchronous flying-around problem is transformed into a two-dimensional control problem in the instantaneous rotation plane of LOS (IRPL). The sliding mode controller is designed to control the LOS direction and vertical LOS direction of the chaser in the IRPL, and the stability of the controller is analyzed. In order to verify the effectiveness of the synchronous flying-around control method, three simulation scenarios are designed. The simulation results verify the effectiveness of the proposed method.

Voice‐over anatomy lectures created by AI‐voice cloning technology: A descriptive article

AbstractThe COVID‐19 pandemic revealed the pivotal role of digital learning and online lecture videos, leading a shift toward blended and flipped classrooms in the post‐pandemic era. This shift calls for development and (or) refreshment of novel online educational resources, such as Voice‐Over PowerPoint (VOPPT) presentations, specifically designed for asynchronous or synchronous learning methods. However, resource limitations often impede the timely delivery of high‐quality instructional materials. In this descriptive article, the use of AI‐voice cloning technology to automate the creation of VOPPT presentation has been explored. Descripts' Overdub tool, an AI‐voice cloning program, was trained on the 15‐min voice sample of an anatomy professor, and the synthesized voice was used to narrate presentations on inguinal canal and extrahepatic biliary anatomy. The educational use of this novel approach was evaluated based on the second‐year undergraduate medical students' qualitative feedback. Voice similarity analysis using Resemblyzer, an open‐source Python tool, showed a high similarity score of 0.92 between the cloned and original voices. Despite this, students raised concerns about the robotic voice, quick pace, punctuation problems, pronunciation difficulties, and expressed reservations about AI‐generated lecture narration. While the cloned voice closely matched the original, the AI‐generated narration fell short of capturing the nuanced details needed for an effective anatomy instruction. This uncovers AI's current limitations in the educational contexts but establishes a foundation for future progress in AI‐voice cloning technologies aimed at enhancing online educational resources for anatomy and medical education.

Data Modeling and Synchronization Method to Align Power Trading Rules for Integrated Energy Management Systems

Integrated energy systems (IESs) couple multiple energy sources to promote clean energy and reduce emissions. IESs need to participate in business activities, such as power trading, aided by automated data-driven systems to achieve optimal and economical operation. However, challenges arise due to the lack of unified data model standards and the semantic ambiguity of rules, on top of the difficulty of synchronizing data across heterogeneous subsystems of integrated energy management systems (IEMSs). Previous research on power trading data models was limited to certain application scenarios and heterogeneities. This study pivots from proposing model standards to a standard neutral way to align power trading rules across IEMS subsystems. The method features a framework for power trading rules and a software platform called the power trading rule synchronizer. The proposed approach can minimize semantic ambiguity and ensure the automated rule synchronization across subsystems of IEMSs. A case study demonstrated the application of the proposed method, saving an estimated 672 man-days in implementing the rules in 16 subsystems of the IEMS, contributing directly and indirectly to reducing emissions. This study provides a foundation for aligning other rules in IEMSs, such as carbon and gas trading rules.

Exploring the Role of DingTalk for Teaching and Learning English Listening Skills in Blended Learning Environments

This study explores how digital platforms such as DingTalk can be used to teach and learn English listening skills as one of the tools for blended learning instructions. These platforms offer synchronous and asynchronous learning methods and provide students with a flexible and interactive platform that promotes real-time communication, peer feedback, and self-paced learning. Although this platform has shown potential benefits for improving listening comprehension using constructivist and social learning theories, drawbacks include technological limitations, insufficient platform features for listening instruction, effective instructional design, and students' need for digital literacy. This article highlights the importance of Dingtalk as one of the tools for blended teaching and learning and the issues to be addressed so this platform can be used to help students' English listening skills. The changes in the dominance of technology in education, like AI and AR, need to be considered for blended learning. The findings suggest that to help students' learning outcomes using this digital platform, educational institutions and teachers need to adapt to the needs of their students continuously.

The research of a linear transmission vibrating system of three motors with a circular distribution by the composite synchronization method

The research of a linear transmission vibrating system of three motors with a circular distribution by the composite synchronization method

Exploring the application of synchronous analysis of physiological signals and facial expressions in emotion recognition

In today's increasingly frequent human-computer interaction, the accurate recognition and response of intelligent systems to human emotions has become the key to improving the user experience. This paper aims to explore the application of physiological signals and facial expression synchronization analysis in emotion recognition. This paper adopts the method of literature review, and summarizes the acquisition techniques of physiological signals and facial expressions, synchronous analysis methods, and their application cases in emotion recognition. At the same time, the limitations and challenges of the existing technology are discussed. The review shows that the synchronous analysis of physiological signals and facial expressions has important application value in the field of emotion recognition, especially in mental health monitoring, educational feedback, and customer service automation. However, the practical application of the technology still faces many challenges, including the real-time nature of data collection, the adaptability of individual differences, and other identification problems. Therefore, future research needs to further optimize data acquisition technology and develop more accurate and personalized analysis algorithms.

A voltage sensorless technique for a shunt active power filter adopting band pass filter under abnormal supply conditions

Shunt active power filters (SAPFs) are effective in addressing power quality issues such as harmonics and voltage unbalance. During abnormal grid conditions, there will be a substantial variation in both the actual and reactive power of the system. Various SAPF control approaches were employed to address these issues. This paper presents an improved bandpass filter technique that serves multiple purposes: extracting the reference current harmonic for SAPF, providing reactive current for power factor correction, and functioning as a backup synchronization method in the event of a loss of bus voltage measurement. Furthermore, it should be minimally affected by the unbalance in supply voltage. The case study model and the proposed reference technique have been executed and validated using the MATLAB software environment.

RBFNN-PSO Intelligent Synchronisation Method for Sprott B Chaotic Systems with External Noise and Its Application in an Image Encryption System.

In the past two decades, research in the field of chaotic synchronization has attracted extensive attention from scholars, and at the same time, more synchronization methods, such as chaotic master-slave synchronization, projection synchronization, sliding film synchronization, fractional-order synchronization and so on, have been proposed and applied to chaotic secure communication. In this paper, based on radial basis function neural network theory and the particle swarm optimisation algorithm, the RBFNN-PSO synchronisation method is proposed for the Sprott B chaotic system with external noise. The RBFNN controller is constructed, and its parameters are used as the particle swarm particle optimisation parameters, and the optimal values of the controller parameters are obtained by the PSO training method, which overcomes the influence of external noise and achieves the synchronisation of the master-slave system. Then, it is shown by numerical simulation and analysis that the scheme has a good performance against external noise. Because the Sprott B system has multiple chaotic attractors with richer dynamics, the synchronization system based on Sprott B chaos is applied to the image encryption system. In particular, the Zigzag disambiguation method for top corner rotation and RGB channel selection is proposed, and the master-slave chaotic system synchronisation sequences are diffused to the disambiguated data streams, respectively. Therefore, the encryption and decryption of image transmission are implemented and the numerical simulation results are given, the random distribution characteristics of encrypted images are analysed using histogram and Shannon entropy methods, and the final results achieve the expected results.