Synchronization Method Research Articles

Impact of Online Learning on Stress and Fatigue Using GSR and SOFI Measurements

The early days of university are often a period of great change and stress for freshman students. Freshman and sophomore students in the Industrial Engineering bachelor’s degree program at University X are adapting to a more flexible learning environment, running two different learning methods, namely synchronous and asynchronous learning methods. This study was conducted to analyze the classification of stress and fatigue levels of undergraduates in the Bachelor Program in Industrial Engineering at University X. Industrial Engineering bachelor’s degree program of University X when undergoing lectures. Stress levels were measured objectively using Galvanic Skin Response (GSR) with a gel electrode type. In contrast, fatigue levels were assessed subjectively through the Swedish Occupational Fatigue Inventory (SOFI) questionnaire. The analysis revealed that the stress levels of students during learning, whether through synchronous or asynchronous methods, were categorized as high, with a higher mean value observed in the synchronous learning method. Conversely, fatigue was classified as mild. Based on these findings, this study proposes implementing structured break schedules during synchronous learning sessions and optimizing asynchronous methods by integrating interactive yet less demanding activities to reduce stress and improve student well-being. Additionally, further ergonomic adjustments to the learning setup and duration are recommended to minimize fatigue.

Removal of fluoride and chloride from waste acid by Bi2O3: comparison between the synchronous and two-step methods

Removal of fluoride and chloride from waste acid by Bi2O3: comparison between the synchronous and two-step methods

Green Synchronous Spectrofluorimetric Method for Simultaneous Determination of Trifluridine and Tipiracil Used for Treatment of Colorectal Cancer in Pharmaceutical Products and Spiked Human Biological Fluids

ABSTRACTTrifluridine and tipiracil can now be determined simultaneously thanks to a novel, quick, sensitive, selective, environmentally friendly, and extremely sensitive approach. To determine the medications under study, the first derivative synchronous spectrofluorimetric technique was used. Trifluridine and tipiracil's first derivative amplitudes have been measured at their respective zero crossing points of 260 and 250 nm. The range of linearity was discovered to be of 5.0–30.0 ng mL−1 for each trifluridine and tipiracil. The limits of detection were found to be 0.834 and 0.376 ng mL−1, while the quantitation limits were 2.53 and 1.14 ng mL−1 for trifluridine and tipiracil, in respective order. The technique worked well for figuring out both medications in their lab‐made mixes in various dosage forms and in spiked human biological fluids (spiked human plasma and urine). The outcomes were contrasted with those of HPLC techniques used in comparison. We employed ethanol as a green solvent. Trifluridine and tipiracil can be ascertained with a sufficient level of precision and accuracy using the suggested procedure: AGREE and Eco‐scale. In comparison to HPLC procedures, the suggested method is inexpensive and straightforward.

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.

Analisis Beban Kerja Mental Mahasiswa Terhadap Sistem Perkuliahan Daring dengan Metode NASA-TLX

The Covid-19 pandemic has posed a challenge to the use of technology in the education sector in Indonesia. This situation has made university students independent learners through online classes. In the beginning of Covid-19 the students at Udayana University have implemented online learning. In this context, students are required to understand the course material and complete assignments as part of learning evaluation, thus creating a distinct workload, including mental workload. To determine the extent of the students' mental workload, measurements were conducted using the NASA-TLX (National Aeronautics and Space Administration Task Load Index) method with 6 indicators. The measurement indicators were based on quantitative courses. This study involved 40 respondents who were students of the Industrial Engineering Study Program at Udayana University. The results showed that the mental workload on students was quite high, as evidenced by 23 out of 40 students in the synchronous method group and quantitative courses having a high WWL (Workload Weighting Level) classification. A high WWL classification was also shown in the asynchronous method group, with 26 students or 65%.

A Soft Start Method for Doubly Fed Induction Machines Based on Synchronization with the Power System at Standstill Conditions

Due to their exceptional operational versatility, doubly fed induction machines (DFIM) are widely employed in power systems comprising variable renewable energy-based electrical generation sources, such as wind farms and pumped-storage hydropower plants. However, their starting and grid synchronization methods require numerous maneuvers or additional components, making the process challenging. In this paper, a soft start method for DFIM, inspired by the traditional synchronization method of synchronous machines, is proposed. This method involves matching the frequencies, voltages, and phase angles on both sides of the main circuit breaker, by adjusting the excitation through the controlled power converter at standstill conditions. Once synchronization is achieved, the frequency is gradually reduced to the rated operational levels. This straightforward starting method effectively suppresses large inrush currents and voltage sags. The proposed method has been validated through computer simulations and experimental tests, yielding satisfactory results.

A retrospective single-center study of transnasal ileus tube insertion accompanied with cap-assisted endoscopic advancement for malignant adhesive bowel obstruction

To investigate the effectiveness of cap-assisted endoscope synchronous advancement and tube direction adjustment for inserting transnasal ileus tubes in patients with malignant adhesive bowel obstruction (MABO). 25 patients with cap-assisted endoscopic synchronous method (Group A, Dec 2023–Apr 2024) were reviewed retrospectively. Accordingly, those with forceps-grasping method (Group B: 27, Aug 2022–Nov 2023) were included as controls. Both groups were similar in terms of age, sex, primary tumor, doctor experience distribution and technical success rate. The proportion of gynecological cancers was the highest in either group. The time required for insertion was shorter in Group A than in Group B (5 vs. 12 min; P = 0.000). Group A also had slightly longer tube insertion length than Group B (129.8 ± 14.1 vs. 121.3 ± 12.0 cm; P = 0.008), and the remission rate of intestinal obstruction symptoms in Group A was similar to that in Group B (75.0% vs. 74.1%; P = 0.940). There were no significant differences in complications between the two groups. One patient suffered MABO recurrence 14 days after withdrawal of the tube. Our findings indicate that transnasal ileus tube insertion with cap-assisted endoscopic synchronous method took shorter time and had the same rate of technical success and advantage of decompression compared with forceps-grasping method.

Intelligent Fault Diagnosis of Inter-Turn Short Circuit Faults in PMSMs for Agricultural Machinery Based on Data Fusion and Bayesian Optimization

The permanent magnet synchronous motor (PMSM) plays an important role in the power system of agricultural machinery. Inter-turn short circuit (ITSC) faults are among the most common failures in PMSMs, and early diagnosis of these faults is crucial for enhancing the safety and reliability of motor operation. In this article, a multi-source data-fusion algorithm based on convolutional neural networks (CNNs) has been proposed for the early fault diagnosis of ITSCs. The contributions of this paper can be summarized in three main aspects. Firstly, synchronizing data from different signals extracted by different devices presents a significant challenge. To address this, a signal synchronization method based on maximum cross-correlation is proposed to construct a synchronized dataset of current and vibration signals. Secondly, applying a traditional CNN to the data fusion of different signals is challenging. To solve this problem, a multi-stream high-level feature fusion algorithm based on a channel attention mechanism is proposed. Thirdly, to tackle the issue of hyperparameter tuning in deep learning models, a hyperparameter optimization method based on Bayesian optimization is proposed. Experiments are conducted based on the derived early-stage ITSC fault-severity indicator, validating the effectiveness of the proposed fault-diagnosis algorithm.

Effective natural rubber vulcanization using electron beam irradiation and DFT driven cross-linking agents

This study explores an eco-friendly and efficient method for vulcanizing natural rubber latex using electron beam irradiation, enhanced by cross-linking agents. Unlike conventional sulfur vulcanization, electron beam vulcanization can occur at room temperature, reducing the need for chemical additives and eliminating toxic waste. Both experimental and theoretical studies were performed to evaluate vulcanization efficiency, utilizing ethylene glycol dimethacrylate (EDMA) and 1,6-hexanediol diacrylate (HDDA) as cross-linking agents. Electron beam irradiation is an effective method for generating reactive radical species via homolytic cleavage of covalent bonds in natural rubber. Quantum mechanical calculations, including density functional theory (DFT) and transition state searches using linear and quadratic synchronous transit methods, were employed to examine molecular structures, energies, and reaction pathways in the vulcanization process. The findings reveal that HDDA demonstrates superior cross-linking performance compared to EDMA, making it the preferred choice for enhancing vulcanization efficiency. These results offer valuable insights for optimizing rubber manufacturing processes, potentially improving the quality and efficiency of industrial rubber production.

Cell Cycle Dynamics in the Microalga Tisochrysis lutea: Influence of Light Duration and Drugs.

Our investigation into Tisochrysis lutea's cell cycle regulation involved natural and chemical synchronization methods to maximize their proportion at the division phase (G2/M). Hence, cultures were grown under different light/dark cycles (24:0, 12:12, and 8:16 h) to assess the impact of extended dark periods on cell division. Flow cytometry analyses of the cell cycle revealed that extending the dark phase resulted in a higher number of cells entering G2/M. However, this remained a minority within the overall culture (peaking at 19.36% ± 0.17 under an 8:16 h L/D cycle). To further enhance synchronization, chemical agents (nocodazole, hydroxyurea, and aphidicolin) were tested for their efficacy in blocking specific cell cycle stages. Only aphidicolin successfully induced significant G2/M accumulation (>90%). The commitment point for cell division was examined by exposing cultures to varying light durations (0 to 8 h) and measuring cell concentration and size distribution every 4 h. Our findings identified a critical minimum cell size ("sizer") of approximately 56.2 ± 0.6 µm3 and a required minimal light exposure ("timer") of 4 h to reliably trigger cell division. These findings highlight key conditions needed for optimal division of Tisochrysis lutea, offering more controlled and efficient cultivation strategies for future biotechnological applications.

Escalation of the Palestinian-Israeli conflict: operation “Home and Garden”

Escalation of the Palestinian-Israeli conflict: operation “Home and Garden”

EEG and brain network analysis in the early diagnosis of Alzheimer's disease

Abstract. The early diagnosis of Alzheimers Disease (AD) is critical for effective intervention and improved patient outcomes. This paper explores the role of electroencephalography (EEG) and brain network analysis in the early detection of AD, with a particular focus on neurofeedback training as a therapeutic intervention. We review the characteristic changes in EEG signals, such as decreased alpha power and increased theta power, and their implications for identifying early cognitive decline. Functional connectivity analysis using coherence and phase synchronization methods reveals disruptions in key brain networks, providing valuable biomarkers for early AD. We also discuss quantitative EEG (qEEG) techniques, including power spectral density and fractal dimension, which enhance diagnostic accuracy. Additionally, mathematical models like the Kuramoto model offer insights into network dynamics and predict disease progression. Integrating EEG with other diagnostic tools, such as MRI and PET, creates a comprehensive multimodal approach. This integrative framework enhances early diagnosis and informs personalized treatment strategies, representing a significant advancement in the field of AD research and clinical practice.

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.