Synchronous Theory Research Articles

Improved Synchronous Characterization Theory for Surface and Interface Mechanical Properties of Thin-Film/Substrate Systems: A Theoretical Study on Shaft-Loaded Blister Test Technique

In this paper, the previously proposed shaft-loaded blister test technique for the synchronous characterization of the surface and interface mechanical properties of a thin-film/substrate system is further studied theoretically. The large deflection problem of the steady shaft-loaded blistering thin film is reformulated by surrendering the small-rotation-angle assumption of the membrane, which was previously adopted in the out-of-plane and in-plane equilibrium and radial geometric equations. A new and more accurate analytical solution to this large deflection problem is presented and is used to improve the previously presented synchronous characterization theory. The new analytical solution is numerically compared with the previous analytical solution to confirm the superiority of the new analytical solution over the previous analytical solution. An experiment is conducted to verify the beneficial effect of the improved synchronous characterization theory on improving the characterization accuracy.

Does the use of mobile instant messaging in the workplace increase employees’ workload?

ABSTRACT Introduction The impact of instant messaging (IM) tools on employee workload is a concern in both academic and professional contexts. Despite the widespread use of mobile instant messaging (MIM) and its challenges for organizations, research on this topic remains limited. Objective This study aims to explore the mediating roles of interactivity and job interruption, and the moderating role of communication quality, in the relationship between MIM use and perceived workload, using the job demands-resources model, distraction-conflict theory, and media synchronicity theory. Method A total of 235 employees completed self-report questionnaires measuring MIM use, interactivity, job interruption, perceived workload, and communication quality. Results The study found that MIM use has indirect effects on perceived workload. While MIM usage increases interactivity, reducing perceived workload, it also increases job interruptions, leading to a higher perceived workload. Mediation analysis showed that both job interruption and interactivity mediate the MIM use-workload relationship. Furthermore, communication quality weakens the negative impact of interactivity on perceived workload and the positive impact of job interruption on perceived workload. Conclusion These findings challenge the belief that IM is solely disruptive in the workplace, highlighting the importance of communication quality for effective management. This enhances our understanding of MIM's role in corporate and personal productivity.

Entrainment and multi-stability of the p53 oscillator in human cells

The tumor suppressor p53 responds to cellular stress and activates transcription programs critical for regulating cell fate. DNA damage triggers oscillations in p53 levels with a robust period. Guided by the theory of synchronization and entrainment, we developed a mathematical model and experimental system to test the ability of the p53 oscillator to entrain to external drug pulses of various periods and strengths. We found that the p53 oscillator can be locked and entrained to a wide range of entrainment modes. External periods far from p53's natural oscillations increased the heterogeneity between individual cells whereas stronger inputs reduced it. Single-cell measurements allowed deriving the phase response curves (PRCs) and multiple Arnold tongues of p53. In addition, multi-stability and non-linear behaviors were mathematically predicted and experimentally detected, including mode hopping, period doubling, and chaos. Our work revealed critical dynamical properties of the p53 oscillator and provided insights into understanding and controlling it. Arecord of this paper's transparent peer review process is included in the supplemental information.

Dynamics Analysis and Adaptive Synchronization of a Class of Fractional-Order Chaotic Financial Systems

It is of practical significance to realize a stable and controllable financial system by using chaotic synchronization theory. In this paper, the dynamics and synchronization are studied for a class of fractional-order chaotic financial systems. First, the stability and dynamics of the fractional-order chaotic financial system are analyzed by using the phase trajectory diagram, time series diagram, bifurcation diagram, and Lyapunov exponential diagram. Meanwhile, we obtain the range of each parameter that puts the system in a periodic state, and we also reveal the relationship of the derivative order and the chaotic behaviors. Then, the adaptive control strategy is designed to achieve synchronization of the chaotic financial system. Finally, the theoretical results and control method are verified by numerical simulations.

Control of Solar Photovoltaic Integrated Universal Active Filter Using Artificial Intelligence Technique

This paper organizes, a different technique based on adaptive filtering is proposed for the control of three phase worldwide active power filter with a solar photovoltaic array integrated at its DC bus. Two adaptive filters along with a zero crossing detection method are used to remove the magnitude of fundamental active component of distorted load currents, which is then used in estimation of reference signal for the shunt active filter. This technique enables extraction of active component of all three phases with reduced mathematical computation. The series active filter control is based on synchronous reference frame theory and it regulates load voltage and maintains it in-phase with voltage at point of common coupling under conditions of voltage sag and swell. In this paper An artificial intelligence technique fuzzy logic controller is used. The performance of the system is evaluated on an MATLAB/SIMULINK software under various dynamic conditions such as sag and swell in voltage at point of common coupling, load unbalancing and change in solar irradiation intensity.

Home Care Nurses at the Heart of the Communication Web: Communication Synchronicity and Effects on the Psychosocial Work Environment

This qualitative study explores how communication practice affects Swedish home care nurses’ psychosocial work environment. Data consisted of interviews and field observations, analyzed from the perspective of Media Synchronicity Theory and the Job-Demand-Control-Support model. Individual home care nurses were found to manage an interorganizational communication web. The results indicated that this web could have a protective function for the nurses. Synchronous communication was found important to control the work situation. Nevertheless, asynchronous communication was enforced when communicating with other health care organizations. This reduced the level of control for the nurses. However, when possible, the nurses also arranged their communication practice to gain control. Thus, local optimization for one group could result in suboptimization for others. We conclude that communication practice should be designed holistically and promote synchronous communication to foster well-functioning interprofessional teamwork and to create a healthy psychosocial work environment for both home care nurses and their collaborators.

Counter-rotating synchronization theory and experiment of tri-rotor actuated with dual-frequency considering adaptive global sliding mode control strategy

In petroleum drilling engineering, self-synchronous vibration screen with single-frequency actuation is difficult to implement the scheduled synchronous behavior caused by its invariance and instability of dynamic characteristics, which usually leads to reduction of the production efficiency. Hence, to solve the problem mentioned above, a dual-frequency counter-rotating synchronization control method among three exciters is presented by combining adjacent cross-coupling control (ACCC) structure with global sliding mode control (GSMC) theory. Firstly, motion differential equation of the vibration system in each direction is derived according to mathematical model of the tri-rotor vibration machine. Secondly, considering exponential reaching law and adaptive control algorithm, the adjacent cross-coupling controller and the vector controller of each induction motor are investigated to achieve the stable zero phase difference synchronization between double-frequency rotors. Subsequently, Runge-Kutta method is introduced to establish the electromechanical coupling control model and prove validity of the control theory. Meanwhile, it is also discussed that the rotors cannot obtain an ideal self-synchronization state since velocity of high-frequency motor is not strictly equal to twice that of low-frequency motor. Finally, based on the experimental test scheme, an experimental prototype related to controlled multi-rotor synchronization vibration system is designed independently, which further verifies the validity of theory and computer simulation. Research shows that the desirable synchronous state of the vibration system can be accurately controlled via the designed control strategy, and the control system can implement diversity of the dynamical characteristics, due to the existence of strong robustness.

On mathematical analysis of synchronization of bidirectionally coupled Kuramoto oscillators under inertia effect

In this article, we analyze the phase synchronization and frequency synchronization for the bidirectionally coupled Kuramoto model under the effect of inertia. Unlike the classical Kuramoto model equipped with all-to-all coupled interaction, in the setting of this model, each oscillator θi only interacts directly with θi+1 and θi−1. The bidirectional interaction is a typical setting of the concatenation in power systems. Additionally, it is necessary to impose the effect of inertia in the Kuramoto model in the applications such as power systems and Josephson junction array. In this article, we first present a theory of the global convergence for frequency synchronization for the identical case. For the non-identical case, we prove that the second-order bidirectionally coupled Kuramoto model exhibits a frequency synchronization if the coupling strength is large, inertia is small, and all oscillators are initially confined to a sector. We emphasize that the arc length of this sector possesses a positive lower bound which is independent of the number of oscillators. If, in addition, all natural frequencies are identical, we further show that the phase synchronization emerges. Moreover, we demonstrate the numerical simulations to support the main results. On the other hand, we observe that the model equipped with large inertia can exhibit the synchronization. Exploring the synchronization theory for large inertia case is left as the future work.

Synchronization of heterogeneous discrete-time fractional-order quaternion-valued neural networks with time delay and parameter uncertainty using the impulsive method

This paper presents theoretical results on the impulsive synchronization of discrete-time fractional-order quaternion-valued neural networks (DFQVNNs) with time delay and parameter uncertainty. First, a useful assumption for parameter uncertainty is put out, predicated on the observation that it is typically brought about by a very tiny disruption. Next, we realize impulsive synchronization for DFQVNNs with the same structure by utilizing the nabla discrete Mittag–Leffler function. We put out a novel synchronization theory for more intricate scenarios in which the architectures of the DFQVNNs are heterogeneous. Finally, the applicability of the theoretical results is demonstrated through numerical examples.

Carbon whiskers reinforced porous glassy carbon composites by synchronous growth

A crystalline and non-crystalline composite of pure carbon was proposed, which is a carbon whiskers reinforced porous glassy carbon composite, where crystalline carbon whiskers support the microscopic pores of non-crystalline glassy carbon matrix. Two allotropes of carbon were produced simultaneously and compounded together in a single high temperature treatment of thermosetting phenolic resin, with aluminum oxide (Al2O3) as a catalyst. A synchronous growth theory was proposed to explain the growth mechanism. In the pyrolysis process of phenolic resin to generate porous glassy carbon, hydrocarbon gas was produced and trapped in the generated pores. By the same time, the hydrocarbon gas in pores was decomposed and grew carbon whiskers by catalysis of Al2O3. With linear thermal expansion coefficient from 2.0∙10−6 to 3.8∙10−6 K−1, thermal conductivity from 1.763 to 2.518 W∙m−1 K−1, specific heat capacity from 0.396 to 0.752 J∙g−1 K−1, thermal diffusivity from 6.115 to 4.598 mm2 s−1, between room temperature (RT) and 500 °C, the Vickers hardness is at 65 MPa, and the fracture toughness is at 0.329 Mpa∙m1/2 in RT. The carbon whiskers reinforced porous glassy carbon composite keeps a balance between thermophysical and mechanical properties, showing its application value in thermal insulation materials and high temperature structure materials.

Bridge damage identification based on synchronous statistical moment theory of vehicle–bridge interaction

AbstractConsidering the weak noise resistance and low identification efficiency of traditional bridge damage identification methods, a data‐driven approach based on synchronous statistical moment theory and vehicle–bridge interaction vibration theory is proposed. This method involves two main steps. First, a two‐axle test vehicle is used to collect acceleration response signals synchronously from adjacent designated measurement points while stationary. This operation is repeated to calculate the second‐order statistical moment curvature (SOSMC) difference of entire bridge points corresponding signals in different states. By comparing with the reference value, the preliminary damage location of the bridge can be obtained. Second, the first‐order modal shape curve is constructed using the second‐order statistical moment (SOSM). The refined identification of bridge damage is then based on an improved direct stiffness back calculation of the bridge's stiffness. This article proposes the synchronization theory for the first time and combines it with the statistical moment clustering method, forming an innovative approach to obtaining structural vibration modes. The effectiveness of this method has been well validated through numerical simulations with different parameters and on‐site bridge tests. The research results indicate that SOSMC indicators have better noise resistance and higher recognition efficiency in identifying damage locations, compared to modal curvature and flexibility curvature indicators. Additionally, compared to transfer rate and random subspace methods, the SOSM method results in smaller error and higher identification efficiency.

Dynamical states associated with the shift in whistling frequency in aeroacoustic system

Self-sustained aeroacoustic oscillations arising from the interactions between the hydrodynamic and acoustic fields are perceived as a whistle. Such whistling can lead to large amplitude acoustic oscillations that have disastrous consequences for engineering systems such as large segmented solid rocket motors and large gas pipelines. The whistling corresponds to the state of limit cycle oscillations (LCO) in dynamical systems theory. An aeroacoustic system exhibits different dynamical states when the bulk flow velocity is varied as a control parameter. Understanding the dynamical states and the transitions between them, as the control parameter is varied, is crucial in designing control strategies for such aeroacoustic oscillations. Previous studies have shown that as the control parameter varies, in an aeroacoustic system that has a flow through orifices, the whistling frequency shifts. We show that such a change in frequency occurs via three different scenarios— (1) direct transition between the two LCOs as an abrupt transition, (2) via a state of intermittency, and (3) via a state of aperiodicity. In the current aeroacoustic system, the abrupt transition between the LCOs is manifested as a bursting behaviour where the amplitude of the acoustic pressure fluctuations abruptly switches between the high and low-amplitude LCOs. Further, we show that the dynamical state and the transition between them during the frequency shift have a correlation with the magnitude of the frequency shift. Using recurrence theory we show that there is a change in the dynamical state of the system during the frequency shift. Further, we use synchronisation theory to investigate the coupled behaviour of the velocity (u′) and the acoustic pressure (p′) fluctuations during the different dynamical states. Our findings imply that u′ and p′ exhibit phase synchronisation (PS) during the state of LCO, corresponding to whistling. In contrast, u′ and p′ are desynchronised during the state of aperiodicity, corresponding to stable operation. Furthermore, the bursts of periodic oscillations during intermittency correspond to the phase-synchronised epochs of periodic u′ and p′, and the aperiodic epochs correspond to the desynchronised aperiodic u′ and p′.

Jung’s Conceptualization of Synchronicity Theory and the Role of Astrology Inside

Abstract Jung’s conceptualization of synchronicity has a relation to his engagement in astrology began in roughly 1906. Jung’s conceptualization of varieties of synchronistic experiences can be divided into non-divinatory and divinatory experiences. Among the divinatory sources, he overlooked the differences between I-Ching divination and astrology. His neglect caused a logical discrepancy in his early synchronicity theory. Forty-six years after his first engagement in astrology, his essay on synchronicity (1952) possesses a long section for his astrological experiment. In his astrological experiment, his problematic understanding of metaphysical and methodological issues behind the experiment led to the failure of his statistical part of the experiment. The case study part of it turns to support his meaningful chance version of synchronicity theory and leads to the acknowledgement of the standard version of synchronicity theory: meaningful chances.

Phase-resolved measurement and control of ultrafast dynamics in terahertz electronic oscillators

As a key component for next-generation wireless communications (6 G and beyond), terahertz (THz) electronic oscillators are being actively developed. Precise and dynamic phase control of ultrafast THz waveforms is essential for high-speed beam steering and high-capacity data transmission. However, measurement and control of such ultrafast dynamic process is beyond the scope of electronics due to the limited bandwidth of the electronic equipment. Here we surpass this limit by applying photonic technology. Using a femtosecond laser, we generate offset-free THz pulses to phase-lock the electronic oscillators based on resonant tunneling diode. This enables us to perform phase-resolved measurement of the emitted THz electric field waveform in time-domain with sub-cycle time resolution. Ultrafast dynamic response such as anti-phase locking behaviour is observed, which is distinct from in-phase stimulated emission observed in laser oscillators. We also show that the dynamics follows the universal synchronization theory for limit cycle oscillators. This provides a basic guideline for dynamic phase control of THz electronic oscillators, enabling many key performance indicators to be achieved in the new era of 6 G and beyond.

A Development Model of the Impact of Social Media on the Emerging Era of Interactive Learning in Sichuan Province, China

This study explores the determinants of teachers’ work performance using social media, drawing on media synchronicity theory (MST), social capital theory (SCT), and integrated marketing communications (IMC) Theory. A comprehensive survey was administered to 622 faculty members across ten prominent universities in Sichuan Province, China, using a 7-point Likert scale for response measurement. Data were collected via structured questionnaires and analyzed using structural equation modeling (SEM). The findings indicate that online communication, information transfer, resource exchange, and social capital positively influence work performance, with social capital and technology stress serving significant mediating roles. This study contributes to the literature by elucidating complex determinants of work performance in the context of higher education and underscores the direct effects of digital communication and resource sharing, as well as the critical mediating roles of social capital and technology stress. However, this study is limited by its focus on a single region and reliance on self-reported data. Future research should include a more diverse sample and incorporate qualitative methods to more deeply understand educators' subjective experiences with social media in educational settings.

The use of virtual nominal groups in healthcare research: An extended scoping review.

The Nominal Group Technique (NGT) is a consensus group method used to synthesize expert opinions. Given the global shift to virtual meetings, the extent to which researchers leveraged virtual platforms is unclear. This scoping review explores the use of the vNGT in healthcare research during the COVID-19 pandemic. Following the Arksey and O'Malley's framework, eight cross-disciplinary databases were searched (January 2020-July 2022). Research articles that reported all four vNGT stages (idea generation, round robin sharing, clarification, voting) were included. Media Synchronicity Theory informed analysis. Corresponding authors were surveyed for additional information. Of 2,589 citations, 32 references were included. Articles covered healthcare (27/32) and healthcare education (4/32). Platforms used most were Zoom, MS Teams and GoTo but was not reported in 44% of studies. Only 22% commented on the benefits/challenges of moving the NGT virtually. Among authors who responded to our survey (16/32), 80% felt that the vNGT was comparable or superior. The vNGT provides several advantages such as the inclusion of geographically dispersed participants, scheduling flexibility and cost savings. It is a promising alternative to the traditional in-person meeting, but researchers should carefully describe modifications, potential limitations, and impact on results.

Soliton synchronization in microresonators with a modulated pump.

Microresonator frequency comb generation from Kerr solitons has become a cutting edge technology, but challenges remain in creating, maintaining, and controlling the solitons. Pump modulation and dual pumping are promising techniques for meeting these challenges. Here we derive the equationof motion of solitons interacting with a modulated pump in the framework of synchronization theory. It implies that the soliton repetition rate locks to the modulation frequency whenever the latter is within a locking range of frequencies around an integer multiple of the free spectral range of the microresonator. We calculate explicitly, numerically, and in perturbation theory the width of the locking range as a function of the amplitude and frequency of the pump and the modulation phase. We show that a highly red-detuned, strong pump that is amplitude-modulated provides the best conditions for entrainment, and that the width of the locking range is proportional to the square of the modulation frequency, limiting the effectiveness of RF modulation as an entrainment method.

Recurrent neural networks-guided vector-valued synchronized key exchange for secure and privacy-preserving communication in Industrial Internet of Things

This paper presents an innovative approach to the problem of key exchange in the Industrial Internet of Things (IIoT) implementation. Recurrent Neural Networks (RNNs) and vector-valued neural synchronization are the key components of the proposed secure transmission method. Drive-response methods are integrated to improve speed in important applications, meeting the continuous need for effective cryptographic key exchange between IIoT devices. Conventional algorithms face drawn-out assessment procedures that jeopardize neural synchronization concealment. This work examines how random input vector generation and synchronization issues in RNNs with drive-response are affected by proportional and non-proportional delays. Furthermore, it delves into an unexplored domain, investigating the synchronization of response-based RNN systems without delays and drive-response-based RNN systems with various proportional delays. It also suggests a simplified analysis of Artificial Neural Networks (ANNs) synchronization, organizing ANNs for session key switch-over using an RNN system. To achieve polynomial and non-polynomial synchronization in the proposed driver response systems, this method offers several benefits: it introduces a polynomial synchronization theory for RNNs to generate synchronized input vectors for ANN synchronization; it uses inequality assessment techniques and Lyapunov formulas to derive relevant control inputs and time-dependent conditions; it establishes the relationship between polynomial and non-polynomial synchronization; and it provides numerical examples demonstrating its effectiveness. It also builds a neural network for generating session keys throughout the IIoT network by aligning vector-valued ANNs in a reciprocal manner. This strategy outperforms previous approaches in the literature, validated through simulations, balances resilience against attacks with minimal computational load, resulting in more effective and resilient industrial applications.

Drivers of industrial sales performance in the agent-buyer chat channel: The role of social and functional content, message valence, and synchronicity

With retailers increasingly taking an omnichannel approach to customer engagement, the online chat has become a strategic communication platform for salesperson-organizational buyer interactions. In this research, we explore chat messages between sales agents and organizational buyers to identify which attributes are more likely to increase sales outcomes (B2B segment). Drawing from social response theory and media synchronicity theory, we develop hypotheses to understand how message content (social versus functional), message valence (positive versus negative), and message progression (synchronicity, or time between responses, and response proportion, or ratio of words typed for salesperson-buyer interactions) influence sales revenue, sales frequency, and sales conversion rates. We test this phenomenon within an auto-manufacturing firm over 714 days, where 19,817 chat conversations yielded 3433 sales. The results show that social content increased sales revenue and sales conversion rates while functional content influenced frequency. Positive message valence influenced all three outcomes while negative valence increased conversion rates. Finally, shorter response times and replies were shown to positively influence organizational buyer purchase behavior. These findings offer implications for sales organizations utilizing live sales agents in their chat platforms and present avenues for future research in this domain.

A New Design of UPQC-Based Hybrid Multi-Carrier Modulation for Transformer Less Grid Connected PV-Based Active Power Filter

In recent times, there has been a growing concern over the augmented power consumption, leading to a pressing need for compensating devices to maintain power quality in grid-connected systems. One extensively employed solution is the Unified Power Quality Conditioner (UPQC), which incorporates both shunt and series active power filters (APFs) connected through a DC-link capacitor. However, traditional systems using compensating devices can be costly and cumbersome, often relying on transformers to interface with the grid. To address these drawbacks, this report proposes a transformer-less networking approach using a multi-level inverter (MLI) that reduces the number of switches in the shunt and series APF. To enable the efficient operation of the MLI in UPQC, the report utilizes Synchronous Reference Frame Theory and Hybrid Multi-Carrier Pulse Width Modulation (H-MCPWM) techniques for reference signal generation and gate control, respectively. MATLAB/Simulink simulation version 2019a is employed to validate the performance of the proposed system, along with a hardware prototype featuring a motor load. A key aspect of the investigation involves conducting harmonic analysis for various modulation indices with a non-linear load. The resulting data is then compared to the outcomes of the conventional model. By exploring this approach, the report aims to showcase the viability of the transformer-less networking of MLI in UPQC, thereby paving the way for more cost-effective and efficient grid-connected systems with improved power quality.