Synchronous Mode Research Articles

Chimera States in Neuro-Inspired Area-Efficient Asynchronous Cellular Automata Networks

Synchronization transition in neuromorphic networks has attracted much attention recently as a fundamental property of biological neural networks, which relies on network connectivity along with different synaptic features. In this work, an area-optimized FPGA implementation of an Asynchronous Cellular Automata Neuron model that exhibits discrete-state neuron dynamics is introduced. The proposed neuron model is capable of reproducing various neuromorphic oscillations observed in biological neurons using less hardware resources than previous implementations. We investigate synchronization transitions with a focus on the emergence of chimera states in a ring-based network consisting of hardware-based neurons with electrical synaptic coupling. In particular, we study the effects on the network’s phase synchronization through changing two control parameters: the coupling range and the coupling strength. We indicate that via proper configuration of the coupling parameters, we influence the synchronization transition and reveal chimera states which have been associated with neurological disorders.

Studying the Efficiency of Parallelization in Optimal Control of Multistage Chemical Reactions

In this paper, we investigate the problem of optimal control of complex multistage chemical reactions, which is considered a nonlinear global constrained optimization problem. This class of problems is computationally expensive due to the inclusion of multiple parameters and requires parallel computing systems and algorithms to obtain a solution within a reasonable time. However, the efficiency of parallel algorithms can differ depending on the architecture of the computing system. One available approach to deal with this is the development of specialized optimization algorithms that consider not only problem-specific features but also peculiarities of a computing system in which the algorithms are launched. In this work, we developed a novel parallel population algorithm based on the mind evolutionary computation method. This algorithm is designed for desktop girds and works in synchronous and asynchronous modes. The algorithm and its software implementation were used to solve the problem of the catalytic reforming of gasoline and to study the parallelization efficiency. Results of the numerical experiments are presented in this paper.

Visual synthesis of uniaxial synchronous deployment mechanisms for solid-surface deployable antennas

A systematic method is proposed to deal with the structure design of solid-surface deployable antennas with the emphasis on mechanism synthesis and interference analysis. The geometric model of the antenna in deployed and folded states is first established, and based on it the expressions of division parameters are derived. Then the stowing scheme is formulated and its corresponding algorithm for finding the precise axis is thus proposed by employing Euler’s rotation theorem plus rigid-body registration. For more efficient synthesis of deployment mechanisms, the mechanism-synthesis model composed of topological models, synchronous modes, modified Grübler–Kutzbach formula, and screw-dependency chart is established, and on this basis several desired mechanisms are obtained. Moreover, the interference during deployment is totally formulated and thus the measures for avoiding interference are given. Finally, the CAD models of three antennas possessing the preferable mechanisms are established, and their kinematic simulations are performed. The simulated results validate the antennas deploy smoothly without interference, and can form precise parabolic reflective surfaces once fully deployed. Consequently, the approach is effective and has advantages of intuition, conciseness and efficiency.

Explosive transitions to synchronization in networks of frequency dipoles.

We reveal that an introduction of frequency-weighted inter-layer coupling term in networks of frequency dipoles can induce explosive synchronization transitions. The reason for explosive synchronization is that the oscillators with synchronization superiority are moderately suppressed. The findings show that a super-linear correlation induces explosive synchronization in networks of frequency dipoles, while a linear or sub-linear correlation excites chimera-like states. Clearly, the synchronization transition mode of networks of frequency dipoles is controlled by the power-law exponent. In addition, by means of the mean-field approximation, we obtain the critical values of the coupling strength within and between layers in two limit cases. The results of theoretical analysis are in good agreement with those of numerical simulation. Compared with the previous models, the model proposed in this paper retains the topological structure of network and the intrinsic properties of oscillators, so it is easy to realize pinning control.

Synchronization dynamics of phase oscillator populations with generalized heterogeneous coupling

The Kuramoto model, serving as a paradigmatic tool, has been used to shed light on the collective behaviors in large ensembles of coupled dynamic agents. It is well known that the model displays a second-order(continuous) phase transition towards synchrony by increasing the homogeneous(uniform) global coupling strength. Recently, there is a great interest in investigating the effects of the heterogeneous patterns on the collective dynamics of coupled oscillator systems. Here, we consider a generalized Kuramoto model of globally coupled phase oscillators with quenched disorder in their natural frequencies and coupling strength. By correlating these two types of inhomogeneity, we systematically explore the impacts of heterogeneous structure, the correlation exponent, and the intrinsic frequency distribution on the synchronized dynamics. We develop an analytic framework for capturing the essential dynamic properties involved in synchronization transition. In particular, we demonstrate that the forward critical threshold describing the onset of synchronization is unaffected by the location of heterogeneity, which, however, does depend crucially on the correlation exponent and the form of frequency distribution. Furthermore, we reveal that the backward critical points featuring the desynchronization transition are significantly shaped by all the considered effects, thereby enhancing or weakening the ability of synchronization transition (bifurcation). Our investigation is a step forward in highlighting the importance of heterogeneous pattern presented in the complex systems, and could, thus, provide significant insights for designing the strategy of inducing and controlling synchronization.

Synchronization dynamics on power grids in Europe and the United States.

Dynamical simulation of the cascade failures on the Europe and United States (U.S.) high-voltage power grids has been done via solving the second-order Kuramoto equation. We show that synchronization transition happens by increasing the global coupling parameter K with metasatble states depending on the initial conditions so that hysteresis loops occur. We provide analytic results for the time dependence of frequency spread in the large-K approximation and by comparing it with numerics of d=2,3 lattices, we find agreement in the case of ordered initial conditions. However, different power-law (PL) tails occur, when the fluctuations are strong. After thermalizing the systems we allow a single line cut failure and follow the subsequent overloads with respect to threshold values T. The PDFs p(N_{f}) of the cascade failures exhibit PL tails near the synchronization transition point K_{c}. Near K_{c} the exponents of the PLs for the U.S. power grid vary with T as 1.4≤τ≤2.1, in agreement with the empirical blackout statistics, while on the Europe power grid we find somewhat steeper PLs characterized by 1.4≤τ≤2.4. Below K_{c}, we find signatures of T-dependent PLs, caused by frustrated synchronization, reminiscent of Griffiths effects. Here we also observe stability growth following the blackout cascades, similar to intentional islanding, but for K>K_{c} this does not happen. For T<T_{c}, bumps appear in the PDFs with large mean values, known as "dragon king" blackout events. We also analyze the delaying or stabilizing effects of instantaneous feedback or increased dissipation and show how local synchronization behaves on geographic maps.

Cooperative control of networked discrete‐event systems: Application to the handling system HANS

A method for the cooperative control of networked discrete-event systems is evaluated experimentally on a handling system. Networked discrete-event systems consist of controlled subsystems, which have to solve local and cooperative tasks. Local tasks are specified by target states of each individual subsystem, whereas cooperative tasks are modelled by synchronous state transitions for neighbouring subsystems. Network units connect the controlled subsystems via a digital network and apply situation dependent communication, if a cooperation is necessary. The experiments show that the proposed method is suitable to provide a flexibly structured handling system and that it is feasible with regard to the computational complexity.

Do zoom meetings really help? A comparative analysis of synchronous and asynchronous online learning during Covid-19 pandemic.

BackgroundOnline learning and teaching were globally popularized due to the impact of Covid‐19. The pandemic has made both synchronous and asynchronous online learning inevitable in regions privileged with the technological affordance.AimsThis study was designed to examine and compare the effectiveness of both learning modes through the Community of Inquiry framework.Materials & MethodsComparative analyses on a sample of N = 170 undergraduate students who took both synchronous and asynchronous online courses in Spring 2021.ResultsThe paired‐sample T‐tests results indicated a significant difference in social presence, cognitive presence and self‐evaluated performance.Discussion & ConclusionTeaching presence significantly influenced social presence and cognitive presence in both learning modes. However, under synchronous learning mode, social presence significantly impacted self‐evaluation, grades and school identification. While social presence only influenced school identification under asynchronous learning mode. Theoretical and practical implications were also included.

On the Mechanisms of Formation of Density Cavities under Instability of Intense Langmuir Oscillations in a Plasma

The paper considers the instability of intense Langmuir oscillations in nonisothermal (Zakharov's model) and cold (Silin's model) 1D plasma. The main attention is paid to the formation of plasma density caverns in the hydrodynamic and hybrid (electrons are described hydrodynamically, ions are described by model particles) representations. In the hydrodynamic representation, with a small number of spectrum modes, large-scale plasma density caverns are observed, which rapidly deepen. This process is supported by the appearance of small-scale perturbations, and phase synchronization of the Langmuir waves of the instability spectrum is observed. This phase synchronization of the spectrum modes is quite capable of fulfilling the role that was previously proposed to be given exclusively to the effect of extrusion of particles from the cavity by the field. In hybrid models, in the region of consideration, ions are described by model particles, the number of which in the one-dimensional case 104-5*105 (which in the three-dimensional case corresponds to the number of particles 1012-1014). The initial spectrum of perturbations is very wide and rather intense, which leads to an explosive growth of perturbations in the Zakharov model and a rapid development of instability in the Silin model. In this case, in the developed instability regime, the formation of many small-scale plasma density caverns is observed. It is the presence of this small-scale modulation due to the Fermi effect that quickly forms the normal distribution of ions over velocities. In this case, the effect of particle heating due to Landau damping loses its primacy. It is shown that the caverns practically do not change their position; phase changes for the spectral components of the plasma density were not observed. Only individual small-scale caverns demonstrate dynamics similar to the development of caverns in the hydrodynamic representation.

Vortex rope interaction with radially protruded solid bodies in an axial turbine: a numerical study

Radially protruded solid rods and their interaction with the rotating vortex rope at part load condition are investigated numerically on an axial model turbine.The commercially available software ANSYS CFX was used to perform the simulation, and the test case was the Porjus U9 Kaplan turbine model operating at a fixed runner blade angle at part load condition. Four rods, with a rod diameter equal to 15% of the runner diameter were evenly distributed in a horizontal plane in the draft tube cone and protruded to a length set to intercept the RVR in its unperturbed trajectory. It is shown that the RVR plunging (synchronous) mode is completely mitigated upstream and downstream of the protruded rods. The RVR rotating (asynchronous) mode is reduced by 47% and 63% at the two monitor positions located upstream of the protruding rods, while only a minor reduction occurs to the first RVR harmonic at the monitor positions located downstream of the protruded rods. The perturbed RVR experiences an increased angular velocity due to the flow area decrease caused by the protruding rods, thus increasing the RVR frequency by approximately 53% compared to the unperturbed value. Investigation of the swirling flow indicates a locally increased swirl in the center of the draft tube downstream of the protruded rods which could explain the reduction of the RVR pressure amplitude. The overall turbine efficiency with solid rods protruded causes a marginally efficiency reduction of 0.85%. However, as the RVR pressure pulsations are reduced significantly, a more comprehensive investigation of the rods impact on the turbine performance and life time should be performed to elucidate the suitability of using solid rod protrusion for RVR mitigation.

Study of the Synchronous Mode of Hysteresis Electromechanical Energy Converters of Conical Configuration

Study of the Synchronous Mode of Hysteresis Electromechanical Energy Converters of Conical Configuration

Multimodal Course Design and Implementation using LEML and LMS for Instructional Alignment

Traditionally, teaching has been centered around classroom delivery. However, the onslaught of the COVID-19 pandemic has cultivated usage of technology, teaching, and learning methodologies for course delivery. We investigate and describe different modes of course delivery that maintain the integrity of teaching and learning. This paper answers to the research questions: 1) What course delivery method our academic institutions use and why? 2) How can instructors validate the guidelines of the institutions? 3) How courses should be taught to provide student learning outcomes? Using the Learning Environment Modeling Language (LEML), we investigate the design and implementation of courses for delivery in the following environments: face-to-face, online synchronous, asynchronous, hybrid, and hyflex. A good course design and implementation are key components of instructional alignment. Furthermore, we demonstrate how to design, implement, and deliver courses in synchronous, asynchronous, and hybrid modes and describe our proposed enhancements to LEML.

THE ROLE OF CLASSROOM INTERACTION IN ONLINE LEARNING: VOICES FROM THE STUDENTS

The importance of classroom interaction in learning has been widely researched. Through the lens of sociocultural theory, classroom interaction could be seen as mediation for learning where learners develop their knowledge and understandings through collaborative activities and dialogic processes which take place during the learning process in class. This paper qualitatively explores the types of classroom interaction that take place in an online learning environment to analyze factors that impacted and shaped classroom interactions. Further, how students perceive each type of interaction and how it might contribute to learning and learners’ satisfaction were also discussed. The study highlights the importance of balancing the use of both synchronous and asynchronous interaction modes to allow maximum classroom interaction. While technology might be a potential tool in encouraging learners to interact more actively and engage in interaction within a less threatening condition, instructors should think carefully about the design of learning activities to create positive classroom interaction with learners, among learners, and between learners and the course materials.

Generic criterion for explosive synchronization in heterogeneous phase oscillator populations

Ordered and disordered behavior in large ensembles of coupled oscillators map to different functional states in a wide range of applications, e.g., active and resting states in the brain and stable and unstable power grid configurations. For this reason, explosive synchronization transitions, which facilitate fast, abrupt changes between these functional states, has recently seen significant interest from researchers. While previous work has identified properties of complex systems that support explosive synchronization, these investigations have been conducted largely on an ad-hoc basis. Here we provide an exact criterion for explosive synchronization in coupled phase oscillator ensembles by investigating the necessary relationship between dynamical and structural disorder. This result provides a critical step towards untangling the intertwined properties of complex systems responsible for abrupt phase transitions and bistability in biological and engineered systems.

EXPERIENCE IN THE ORGANIZATION OF THE EDUCATIONAL PROCESS IN THE MEDICAL UNIVERSITY DURING THE WAR IN UKRAINE

The article summarizes the students' learning experience, which was developed by the efforts of the entire staff of the medical university during the war. The high-quality educational activity involves the organization of a continuous educational process under the condition of complete safety of all participants of this process, which can be ensured by using synchronous and asynchronous educational modes. A necessary component of professional training is the acquisition of practical skills and communication skills of students, which was carried out in the project "Summer school for consolidation of practical skills". As part of the cooperation between universities in the implementation of the principle of academic mobility of students, students from other higher education institutions participated in the project.

Application of green first derivative synchronous spectrofluorometric method for quantitative analysis of fexofenadine hydrochloride and pseudoephedrine hydrochloride in pharmaceutical preparation and spiked human plasma

Fexofenadine hydrochloride and pseudoephedrine hydrochloride are prescribed in a combined dosage form for the treatment of allergic rhinitis. In the present work, a sensitive synchronous fluorescence spectroscopic method was applied in conjunction with first derivative for quantitative estimation of fexofenadine hydrochloride and pseudoephedrine hydrochloride in pure form, pharmaceutical tablets and spiked human plasma. Fexofenadine hydrochloride showed its conventional emission spectrum at 294 nm when excited at 267 nm. On the other hand, pseudoephedrine hydrochloride showed its conventional emission spectra at 286 nm when excited at 261 nm. The fluorescence intensities were greatly enhanced by the use of sodium dodecyl sulphate as a micellar surfactant. Application of the synchronous mode to measure the fluorescence spectra of the above drugs provided sharp narrowing bands, but the overlap was not completely resolved. Derivatization of the synchronous spectra to the first order completely resolved the overlap of the fluorescence spectra and allowed simultaneous quantitative determination of the drugs under study. Fexofenadine hydrochloride and pseudoephedrine hydrochloride could be determined from their first-order synchronous spectra at 286 and 294 nm, respectively, without interfering with each other. The method showed linearity with an excellent correlation coefficient in the concentration range of 100–1500 ng/mL for Fexofenadine hydrochloride and 50–1000 ng/mL for pseudoephedrine hydrochloride. The method was successfully applied for the simultaneous determination of the studied drugs in pharmaceutical formulation, with mean percent recoveries for Fexofenadine hydrochloride and pseudoephedrine hydrochloride of 99.49 ± 0.931 and 98.67 ± 0.634, respectively, and in spiked human plasma, with mean percent recoveries for Fexofenadine hydrochloride and pseudoephedrine hydrochloride of 95.21 ± 1.938 and 94.89 ± 1.763, respectively. Furthermore, the greenness of the described method was assessed using four different tools namely, the national environmental method index, the analytical eco-scale, the green analytical procedure index and the AGREE evaluation method. The proposed method seemed to be superior to the reported HPLC method with respect to the metrics of the greenness characters.

Stylometric features in librarian’s responses to user queries: implications for user interaction in digital information services

PurposeThe purpose of this study is to explore linguistic stylometric patterns encompassing lexical, syntactic, structural, sentiment and politeness features that are found in librarians’ responses to user queries.Design/methodology/approachA total of 462 online texts/transcripts comprising answers of librarians to users’ questions drawn from the Internet Public Library were examined. A Principal Component Analysis, which is a data reduction technique, was conducted on the texts and transcripts. Data analysis illustrates the three principal components that predominantly occur in librarians’ answers: stylometric richness, stylometric brevity and interpersonal support.FindingsThe results of the study have important implications in digital information services because stylometric features such as lexical richness, structural clarity and interpersonal support may interplay with the degree of complexity of user queries, the (a)synchronous communication mode, application of information service guideline and manuals and overall characteristics and quality of a given digital information service. Such interplay may bring forth a direct impact on user perceptions and satisfaction regarding interaction with librarians and the information service received through the computer-mediated communication channel.Originality/valueTo the best of the authors’ knowledge, the stylometric features encompassing lexical, syntactic, structural, sentiment and politeness using Principal Component Analysis have not been explored in digital information/reference services. Thus, there is an emergent need to explore more fully how linguistic stylometric features interplay with the types of user queries, the asynchronous online communication mode, application of information service guidelines and the quality of a particular digital information service.

Composite error-based intelligent smooth sliding mode control of a dual parallel robot for automobile electro-coating conveying

Different coating technological requirements of automobile electro-coating control system have different desired trajectories. For a dual parallel robot used for automobile electro-coating conveying (DPRAEC), an intelligent tracking smooth sliding mode synchronization control method (ITSSMSC) is proposed to achieve better tracking control performance with high synchronization and flexibility for the system under different desired trajectories. According to the dual parallel and symmetrical structure of the robot, the sliding surface is designed based on a composite error. A deep neural network with multi-hidden layer is trained by deep learning algorithms. Then, any given trajectories caused by different coating technological requirements could be tracked without tuning additional parameters and the synchronous performance could be guaranteed. The convergence of the network training process and the stability of the ITSSMSC are proved theoretically. Compared with the synchronization proportion-derivative control, the sliding mode control based on constant velocity reaching law without synchronization control and the smooth sliding mode synchronization control without training, simulation and experimental results demonstrate the effectiveness of the proposed approach. Compared with synchronization proportion-derivative control, the maximum tracking errors of constant velocity reaching law without synchronization control among each active joint are, respectively, reduced 92.2%, 94.7%, 98.8%. The maximum tracking errors of smooth sliding mode synchronization control and ITSSMSC in [Formula: see text] direction are, respectively, 9.06×10−5m and 1.01×10−9m. The maximum tracking errors of smooth sliding mode synchronization control and ITSSMSC in [Formula: see text] angle are, respectively, 4.50×10−3rad and 1.45×10−4rad. Therefore, the proposed control method could improve the tracking control performance and synchronization performance simultaneously under different desired trajectories.

EVALUATION OF IMPLEMENTATION OF VIRTUAL SYNCHRONOUS LEARNING MODA IN TEACHER TRAINING

Virtually based training is an alternative way for academics and training to equip students with the skills necessary for any career. The synchronous learning mode as a training mode is considered effective in improving the skills of digital educators, especially in the digital era of the 21st century. The use of this mode is increasing, but its effect on learning retention in teacher training has not scientifically proven. This study aims to implement a HOTS-based training program using synchronous learning media at an educational technology-based company. The research method used is descriptive-quantitative to obtain an overview of the implementation of the training from the aspects of reactions, cognitive understanding, and learning outcomes that are applied after. The results showed that the participants' reaction to the training followed by using synchronous learning mode were very good, there was a change in understanding related to HOTS learning between before training and before training it could be applied in the day-to-day teaching process.

통역 스터디에서 ICT 툴 활용의 가능성 - 사운드클라우드(SoundCloud)와 오다시티(Audacity)를 중심으로 -

Unlike the interpreting education community in Korea, which provided synchronous mode of online learning using video conferencing platforms during the spread of COVID-19, interpreting education institutions abroad such as EMCI Universities provided both synchronous and asynchronous education using various ICT tools. Noting this fact, this study aims to introduce a music sharing platform, “SoundCloud” and a recording and editing program, “Audacity” and propose these tools can be effectively used in self learning sessions of interpreting. In addition, this paper identifies pros and cons of each tool, based on users’ experience and suggests potential areas of application. In a group interview, interviewees noted that the two platforms offer many benefits when they are used for a wide range of applications including interpreting practice and number conversion without time and space constraints, while they reduce psychological stress during practice sessions, leading to higher motivation.