The Behavior of Synchronized Frequency in Weakly Coupled Nonidentical Periodic Oscillators

2017 ◽  
Vol 27 (01) ◽  
pp. 1750008
Author(s):  
Priyom Adhyapok ◽  
Mahashweta Patra ◽  
Soumitro Banerjee

Interaction between dynamical systems has been a subject of intensive study for the past couple of decades. These studies have mainly focused on synchronization of chaotic systems, conditions of different kinds of synchronized behavior, amplitude death, etc. Synchronization of periodic oscillators and the frequency of the resulting synchronized behavior have remained relatively unexplored. In this paper we consider synchronization of nonidentical periodic oscillators for different coupling schemes, and study the nature of the synchronized frequency. Based on numerical and experimental observations we show that for directly coupled oscillators, the synchronized frequency lies between the individual frequencies and its value does not depend on the coupling constant, while for indirectly coupled oscillators the synchronized frequency lies out of the range and depends on the strength of coupling. We explain the different frequency behaviors of directly and indirectly coupled systems by analytically deriving the expressions of synchronized frequency under certain simplifying assumptions.

2021 ◽  
Vol 4 (1) ◽  
pp. 17-26
Author(s):  
Albrecht Classen

This study reexamines the meaning of education in global terms as the foundation of all open and democratic societies both in the past and the present. Literary studies create useful mirrors taking the learner into the past where parallel cases of human problems and conflicts existed. The learning experience then allows the individual to carry the new insights back to the own presence and to apply them to current situations. This process can and must be applied particularly to the principle of tolerance, one of the highest ideals in all of education. In order to illustrate this concept, this study examines Boccaccio’s Decameron and Gotthold Ephraim Lessing’s Nathan the Wise as model cases for global education leading to a more peaceful and mutually respectful world. With all due respect for religion, hating and murdering other people for religious reasons betrays the very principles of that religion whatever denomination or creed it might be. Ignorance and lack of education make it possible for fanatics or zelots to whip the masses into violent actions against those who adhere to another faith. One of the major tasks by educators is to introduce rationality, mutual respect, honor, and dignity, which is all possible through an intensive study of well-chosen literary texts for class discussions addressing world religions.


Complexity ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
J. L. Echenausía-Monroy ◽  
C. A. Rodríguez-Martíne ◽  
L. J. Ontañón-García ◽  
J. Alvarez ◽  
J. Pena Ramirez

This study presents the effectiveness of dynamic coupling as a synchronization strategy for fractional chaotic systems. Using an auxiliary system as a link between the oscillators, we investigate the onset of synchronization in the coupled systems and we analytically determine the regions where both systems achieve complete synchronization. In the analysis, the integration order is considered as a key parameter affecting the onset of full synchronization, considering the stability conditions for fractional systems. The local stability of the synchronous solution is studied using the linearized error dynamics. Moreover, some statistical metrics such as the average synchronization error and Pearson’s correlation are used to numerically identify the synchronous behavior. Two particular examples are considered, namely, the fractional-order Rössler and Chua systems. By using bifurcation diagrams, it is also shown that the integration order has a strong influence not only on the onset of full synchronization but also on the individual dynamic behavior of the uncoupled systems.


Author(s):  
Zaihua Wang ◽  
Haiyan Hu

This paper presents an energy analysis of the amplitude death, a phenomenon that the individual oscillators cease to oscillate when coupled and go to an equilibrium motion instead, of a pair of coupled oscillators with time delay that are slightly perturbed from two undamped oscillators and with delayed coupling. The energy analysis reveals that amplitude death, as well as the stability of the phase-locked periodic solutions, can be justified by the sign of the averaged total powers along a special function with harmonic entries, rather than along arbitrary solution of the coupled oscillators as in the application of the method of Lyapunov’s function for stability analysis. An illustrative example is given to show the effectiveness of the present method.


Author(s):  
Mikhail Konstantinov

The aim of the article is to concretize the concept of political ideology in the aspect of its matrix structure and in the context of the cognitive-evolutionary approach. Based on Michael Frieden's morphological approach to the analysis of ideological consciousness, the concept of cognitive-ideological matrices is introduced, which allows us to describe the process of transition from proto-ideological to ideological concepts proper, especially at the level of individual consciousness. The identification of the ideological concept as the main “gene” of conceptual variability and inheritance made it possible to describe the main parameters of the evolution of political ideologies and associate it with changes taking place at the individual consciousness level. The described concept was tested in a series of sociological studies of youth consciousness conducted in 2015-2016 and 2018-2020. As a result of the study, it was possible to first identify the “zero level” of ideology, at which the minds of young respondents are potentially open to the influence of diverse and often mutually exclusive ideological orientations, and second, to pinpoint the changes that have occurred in the cognitive ideological matrices of Rostov-on-Don students over the past five years. This study was conducted by scientists from the southern Federal University.


2019 ◽  
Vol 26 (24) ◽  
pp. 4506-4536 ◽  
Author(s):  
Iris E. Allijn ◽  
René P. Brinkhuis ◽  
Gert Storm ◽  
Raymond M. Schiffelers

Traditionally, natural medicines have been administered as plant extracts, which are composed of a mixture of molecules. The individual molecular species in this mixture may or may not contribute to the overall medicinal effects and some may even oppose the beneficial activity of others. To better control therapeutic effects, studies that characterized specific molecules and describe their individual activity that have been performed over the past decades. These studies appear to underline that natural products are particularly effective as antioxidants and anti-inflammatory agents. In this systematic review we aimed to identify potent anti-inflammatory natural products and relate their efficacy to their chemical structure and physicochemical properties. To identify these compounds, we performed a comprehensive literature search to find those studies, in which a dose-response description and a positive control reference compound was used to benchmark the observed activity. Of the analyzed papers, 7% of initially selected studies met these requirements and were subjected to further analysis. This analysis revealed that most selected natural products indeed appeared to possess anti-inflammatory activities, in particular anti-oxidative properties. In addition, 14% of the natural products outperformed the remaining natural products in all tested assays and are attractive candidates as new anti-inflammatory agents.


Author(s):  
Abbie J. Shipp

Temporal focus is the individual tendency to characteristically think more or less about the past, present, and future. Although originally rooted in early work from psychology, research on temporal focus has been steadily growing in a number of research areas, particularly since Zimbardo and Boyd’s (1999) influential article on the topic. This chapter will review temporal focus research from the past to the present, including how temporal focus has been conceptualized and measured, and which correlates and outcomes have been tested in terms of well-being and behavior. Based on this review, an agenda for research is created to direct temporal focus research in the future.


2021 ◽  
Vol 37 (1) ◽  
Author(s):  
Gerhard Johan Klopper ◽  
Oladele Vincent Adeniyi ◽  
Kate Stephenson

Abstract Background The larynx has multiple composite functions which include phonation, airway protection, and sensory control of respiration. Stenosis of the larynx and trachea were first recorded by O’Dwyer in 1885 and by Colles in 1886, respectively. Initially, the aetiology of laryngotracheal stenosis was predominantly infective. Currently, the leading cause is iatrogenic injury to the laryngotracheal complex secondary to prolonged ventilation in an intensive care unit. Main body Laryngotracheal stenosis is a complex and diverse disease. It poses a major challenge to the surgeon and can present as an airway emergency. Management typically demands the combined involvement of various disciplines including otorhinolaryngology, cardiothoracic surgery, anaesthesiology, interventional pulmonology, and radiology. Both the disease and its management can impact upon respiration, voice, and swallowing. The incidence of iatrogenic laryngotracheal stenosis has reflected the evolution of airway and intensive care whilst airway surgery has advanced concurrently over the past century. Correction of laryngotracheal stenosis requires expansion of the airway lumen; this is achieved by either endoscopic or open surgery. We review the relevant basic science, aetiopathogenesis, diagnosis, management, and treatment outcomes of LTS. Conclusion The choice of surgical procedure in the management of laryngotracheal stenosis is often dictated by the individual anatomy and function of the larynx and trachea, together with patient factors and available facilities. Regardless of how the surgeon chooses to approach these lesions, prevention of iatrogenic laryngotracheal damage remains of primary importance.


Author(s):  
Kwo-Tsao Chiang ◽  
Min-Yu Tu ◽  
Chao-Chien Cheng ◽  
Hsin-Hui Chen ◽  
Wun-Wei Huang ◽  
...  

Hypoxia remains a flight-safety issue in terms of aviation medicine. Hypoxia-awareness training has been used to help aircrew members recognize personal hypoxia symptoms. There is still no study, as yet, to establish the association of within-subject data between inflight hypoxia events and the altitude chamber. The main purpose of our study was to use paired subjects’ data on inflight hypoxia symptoms compared with those experienced during training. A questionnaire was developed to obtain information on military aircrew members in 2018. Among 341 subjects, 46 (13.49%) suffered from inflight hypoxia. The majority of the subjects detected ongoing inflight hypoxia on the basis of their previous experience with personal hypoxia symptoms or sensations in previous chamber flights. Of the top five hypoxia symptoms, the data revealed that hot flashes, poor concentration, and impaired cognitive function appeared both during the inflight events and during the hypoxia-awareness training. The occurrence rate of hypoxia symptoms was found to not be significantly different between the in-flight events and the past chamber flights through an analysis of within-subject data. Because the individual memory had faded away over time, fresher hypoxia awareness training is still mandatory and valuable to recall personal hypoxia experience for military aircrew members.


Author(s):  
Hans-Jakob Steiger

AbstractConsiderable progress has been made over the past years to better understand the genetic nature and pathophysiology of brain AVM. For the actual review, a PubMed search was carried out regarding the embryology, inflammation, advanced imaging, and fluid dynamical modeling of brain AVM. Whole-genome sequencing clarified the genetic origin of sporadic and familial AVM to a large degree, although some open questions remain. Advanced MRI and DSA techniques allow for better segmentation of feeding arteries, nidus, and draining veins, as well as the deduction of hemodynamic parameters such as flow and pressure in the individual AVM compartments. Nonetheless, complete modeling of the intranidal flow structure by computed fluid dynamics (CFD) is not possible so far. Substantial progress has been made towards understanding the embryology of brain AVM. In contrast to arterial aneurysms, complete modeling of the intranidal flow and a thorough understanding of the mechanical properties of the AVM nidus are still lacking at the present time.


2021 ◽  
Vol 54 (3) ◽  
pp. 1-33
Author(s):  
Blesson Varghese ◽  
Nan Wang ◽  
David Bermbach ◽  
Cheol-Ho Hong ◽  
Eyal De Lara ◽  
...  

Edge computing is the next Internet frontier that will leverage computing resources located near users, sensors, and data stores to provide more responsive services. Therefore, it is envisioned that a large-scale, geographically dispersed, and resource-rich distributed system will emerge and play a key role in the future Internet. However, given the loosely coupled nature of such complex systems, their operational conditions are expected to change significantly over time. In this context, the performance characteristics of such systems will need to be captured rapidly, which is referred to as performance benchmarking, for application deployment, resource orchestration, and adaptive decision-making. Edge performance benchmarking is a nascent research avenue that has started gaining momentum over the past five years. This article first reviews articles published over the past three decades to trace the history of performance benchmarking from tightly coupled to loosely coupled systems. It then systematically classifies previous research to identify the system under test, techniques analyzed, and benchmark runtime in edge performance benchmarking.


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