scholarly journals The Impact of Global Communication Latency at Extreme Scales on Krylov Methods

2012 ◽  
pp. 428-442 ◽  
Author(s):  
Thomas J. Ashby ◽  
Pieter Ghysels ◽  
Wim Heirman ◽  
Wim Vanroose
Keyword(s):  
Global Communication ◽  
Krylov Methods ◽  
Communication Latency ◽  
The Impact

A Newton-Krylov Based Solver for Modeling Finite Rate Chemistry

2002 ◽  
Author(s):  
David H. Wang ◽  
Michael J. Bockelie ◽  
Marc A. Cremer ◽  
J.-Y. Chen
Keyword(s):  
Linear Equations ◽  
Reacting Flows ◽  
Full Scale ◽  
Picard Iteration ◽  
Reacting Flow ◽  
Krylov Methods ◽  
Finite Rate ◽  
Utility Boiler ◽  
Chemically Reacting ◽  
The Impact

To date, computational fluid dynamics (CFD) codes aimed at solving practical engineering problems involving chemically reacting flow have incorporated relatively simple descriptions of the chemical mechanisms involved. Techniques are now available to create reduced mechanisms that faithfully represent detailed chemical descriptions over an appropriate range of conditions using many fewer species. However, including reduced mechanisms into a CFD analysis typically leads to numerical difficulties. In a recent project, a new modeling tool was created that utilizes a combination of state-of-the-art techniques used by Reaction Engineering International (REI) for modeling finite rate chemistry in chemically reacting flows using reduced mechanisms with emerging Newton-Krylov methods for solving systems of non-linear equations. For tests problems ranging from geometrically simple combustion problems to full-scale utility boiler simulations, the Newton-Krylov solver has reduced the CPU time to achieve a solution by up to 60% compared to our traditional Picard iteration method. This paper discusses the implementation of the Newton-Krylov solver into the REI combustion code, the impact of parameters on the performance of the Newton-Krylov solver for solving problems using reduced mechanisms, and demonstration of the Newton-Krylov solver on full-scale utility boiler NOx simulations.

The Internet and the End of the National Communication System: Uncertain Predictions of an Uncertain Future

1998 ◽  
Vol 75 (1) ◽  
pp. 28-34 ◽  
Author(s):  
James W. Carey
Keyword(s):  
Nineteenth Century ◽  
Technical Change ◽  
Communication System ◽  
The Internet ◽  
Global Communication ◽  
National System ◽  
Uncertain Future ◽  
The Impact ◽  
Network Era

The Internet should be understood as the first instance of a global communication system. That system, in turn, is displacing a national system of communications which came into existence at the end of the nineteenth century as a result of the railroad and telegraph, and was “perfected” in subsequent innovations through television in the network era. Such transformations involve not only technical change but the complex alteration of physical, symbolic, and media ecologies which together will determine the impact of the medium.

scholarly journals Demonstrating the Impact of LTE Communication Latency for Industrial Applications

2019 ◽  
Author(s):  
Fedor Polunin ◽  
Dick Carrillo Melgarejo ◽  
Tuomo Lindh ◽  
Antti Pinomaa ◽  
Pedro H. J. Nardelli ◽  
...  
Keyword(s):  
Industrial Applications ◽  
Communication Latency ◽  
The Impact

scholarly journals Coordinated Control in VSC-HVDC Multi-Terminal Systems to Improve Transient Stability: The Impact of Communication Latency

Energies ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3638 ◽  
Author(s):  
Javier Renedo ◽  
Aurelio García-Cerrada ◽  
Luis Rouco ◽  
Lukas Sigrist
Keyword(s):  
Transient Stability ◽  
Reactive Power ◽  
Control Strategies ◽  
Weighted Average ◽  
Frequency Measurement ◽  
Average Frequency ◽  
Voltage Source ◽  
Communication Delays ◽  
Communication Latency ◽  
The Impact

Power transmission is the main purpose of high voltage direct current systems based on voltage source converters (VSC-HVDC). Nevertheless, this type of system can also help to improve transient stability by implementing suitable supplementary controllers. Previous work proposed active- (P) and reactive-power (Q) control strategies in VSC-HVDC multi-terminal systems (VSC-MTDC, for short) to improve transient stability, producing significant improvements. In those strategies, each VSC station of the MTDC system compares its frequency measurement with the average of the frequencies measured by all converter stations of the MTDC system (weighted-average frequency, WAF) in order to modulate its own P and Q injections. Hence, a communication system is required. This paper presents a detailed analysis of the impact of communication latency on the performance of those control strategies. The communication delays have been modelled using a Padé’s approximation and their impact on the performance of the control strategies have been assessed by means of time-domain simulation in PSS/E. The effect of the control strategies on transient stability has been quantified with the critical clearing time (CCT) of a set of faults. Results show that the control strategies analysed present good results for realistic values of communication delays.

scholarly journals Rethinking the Dialogue of Cultures in the Conditions of Global Communication and Information Revolution

2021 ◽  
Vol 4 (2) ◽  
pp. 259-269
Author(s):  
Inna Kostyria ◽  
Maryna Shevchenko
Keyword(s):  
International Relations ◽  
Intercultural Dialogue ◽  
Information Revolution ◽  
Universal Method ◽  
Global Communication ◽  
Modern Culture ◽  
Intercultural Interaction ◽  
Analysis And Synthesis ◽  
Effective Development ◽  
The Impact

The purpose of the research is to identify the features of intercultural dialogue in the context of global communication and information revolution, to reveal changes in the principle of intercultural dialogue in the new environment and to show the impact of culture on modern international relations. Research methodology. Analytical research methods based on methods of analysis and synthesis were used by the authors to reveal the essence of dialogue and its disclosure as a universal method of research not only personality but also culture when the cultural basis turns dialogue into the need of everyday life. Scientific novelty. Peculiarities of dialogue as a basis of intercultural interaction in modern conditions are revealed. The concepts of dialogue and discussion, as well as intrapersonal dialogue within each social subject, in the consciousness of each person, where there are two different positions of consciousness, are revealed and analyzed. Conclusions. The study analyzes new approaches to the principle of intercultural dialogue for intercultural interaction. It is shown that modern culture enters into dialogue only as a whole, characterized by the unity of meanings, their perfection and certainty. The circumstances under which culture in times of crisis seeks its paradigm in a new way are analyzed. It is emphasized that each culture enters into a dialogue in its own unique manner. It is proved that culture cannot exist without the eternal search for the Other, comparison and collation with it. The need for intercultural communication for the effective development of modern international relations based on mutual respect and tolerance is studied.

Technological Advances in the Maritime Sector: Some Implications for Trade, Modernization and the Process of Globalization in the Nineteenth Century

2010 ◽  
Author(s):  
David M. Williams ◽  
John Armstrong
Keyword(s):  
Communication Systems ◽  
World Economy ◽  
New World ◽  
Maritime Transport ◽  
Global Communication ◽  
The Third ◽  
Technological Advances ◽  
Global Age ◽  
The Impact ◽  
The Relationship

This essay examines the impact of three tremendous developments in maritime transport technology - the steamship, the telegraph, and the railway - on global industrialisation and the advent of the ‘Second Global Age’. It is divided into three parts: the first surveys the development of steam navigation and locomotion by country and continent; the second explores the relationship between maritime trade and the ‘new world economy’ - particularly the impact of shortened distances and the increase in availability of information; and the third examines the challenges for maritime merchants that developed alongside the improved global communication systems. It concludes that both transport and communication were essential to the development of a world economy, and that British maritime activity was a crucial contributory element.

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