scholarly journals Performance of distributed multiscale simulations

2014 ◽  
Vol 372 (2021) ◽  
pp. 20130407 ◽  
Author(s):  
J. Borgdorff ◽  
M. Ben Belgacem ◽  
C. Bona-Casas ◽  
L. Fazendeiro ◽  
D. Groen ◽  
...  
Keyword(s):  
Load Distribution ◽  
Large Scale ◽  
Multiscale Simulations ◽  
Distributed Resources ◽  
Multiple Resources ◽  
The Third ◽  
Simulation Speed ◽  
Local Resources ◽  
Second Mode ◽  
Different Characteristics

Multiscale simulations model phenomena across natural scales using monolithic or component-based code, running on local or distributed resources. In this work, we investigate the performance of distributed multiscale computing of component-based models, guided by six multiscale applications with different characteristics and from several disciplines. Three modes of distributed multiscale computing are identified: supplementing local dependencies with large-scale resources, load distribution over multiple resources, and load balancing of small- and large-scale resources. We find that the first mode has the apparent benefit of increasing simulation speed, and the second mode can increase simulation speed if local resources are limited. Depending on resource reservation and model coupling topology, the third mode may result in a reduction of resource consumption.

Instabilities in the slit-jet flow field

1983 ◽  
Vol 132 ◽  
pp. 79-86 ◽  
Author(s):  
J. F. Foss ◽  
D. Korschelt
Keyword(s):  
Reynolds Number ◽  
Flow Field ◽  
Large Scale ◽  
Jet Flow ◽  
Instability Mode ◽  
Regular Pattern ◽  
Additional Information ◽  
The Third ◽  
Second Mode ◽  
Convection Speed

Three modes of instabilities in the slit-jet flow field are recognized. Additional evidence for the universality of the Strouhal number for the second mode ST = fw/U0 ≈ 0.43 and additional information on the wavelength (λ) between, and convection speed uc of the symmetrically placed, large-scale motions that result from this instability are presented. Specifically λ/w ≈ 1.2 and uc/U0 ≈ 0.51. The third instability mode is initiated at a Reynolds number U0w/v of approximately 1600; this instability results in a loss of the regular pattern associated with the large-scale motions.

Higher-order flow modes in turbulent Rayleigh–Bénard convection

2016 ◽  
Vol 805 ◽  
pp. 31-51 ◽  
Author(s):  
Heng-Dong Xi ◽  
Yi-Bao Zhang ◽  
Jian-Tao Hao ◽  
Ke-Qing Xia
Keyword(s):  
Large Scale ◽  
Experimental Studies ◽  
Higher Order ◽  
Working Fluid ◽  
Dynamical Process ◽  
Total Flow ◽  
Flow Energy ◽  
The Third ◽  
Higher Order Modes ◽  
Second Mode

We present experimental studies of higher-order modes of the flow in turbulent thermal convection in cells of aspect ratio ($\unicode[STIX]{x1D6E4}$) 1 and 0.5. The working fluid is water with the Prandtl number ($Pr$) kept at around 5.0. The Rayleigh number ($Ra$) ranges from $9\times 10^{8}$ to $6\times 10^{9}$ for $\unicode[STIX]{x1D6E4}=1$ and from $1.6\times 10^{10}$ to $7.2\times 10^{10}$ for $\unicode[STIX]{x1D6E4}=0.5$. We found that in $\unicode[STIX]{x1D6E4}=1$ cells, the first mode, which corresponds to the large-scale circulation (LSC), dominates the flow. The second mode (quadrupole mode), the third mode (sextupole mode) and the fourth mode (octupole mode) are very weak, on average these higher-order modes each contains less than 4 % of the total flow energy. In $\unicode[STIX]{x1D6E4}=0.5$ cells, the first mode is still the strongest but less dominant, the second mode becomes stronger which contains 13.7 % of the total flow energy and the third and the fourth modes are also stronger (containing 6.5 % and 1.1 % of the total flow energy respectively). It is found that during a reversal/cessation, the amplitude of the second mode and the remaining modes experiences a rapid increase followed by a decrease, which is opposite to the behaviour of the amplitude of the first mode – it decreases to almost zero then rebounds. In addition, it is found that during the cessation (reversal) of the LSC, the second mode dominates, containing 51.3 % (50.1 %) of the total flow energy, which reveals that the commonly called cessation event is not the cessation of the entire flow but only the cessation of the first mode (LSC). The experiment reveals that the second mode and the remaining higher-order modes play important roles in the dynamical process of the reversal/cessation of the LSC. We also show direct evidence that the first mode is more efficient for heat transfer. Furthermore, our study reveals that, during the cessation/reversal of the LSC, $Nu$ drops to its local minimum and the minimum of $Nu$ is ahead of the minimum of the amplitude of the LSC; and reversals can be distinguished from cessations in terms of global heat transport. A direct velocity measurement reveals the flow structure of the first- and higher-order modes.

Pèlerinages barrésiens

2013 ◽  
pp. 116-123
Author(s):  
Claire Bompaire-Evesque
Keyword(s):  
Large Scale ◽  
The Self ◽  
Joan Of Arc ◽  
The Third ◽  
National Importance ◽  
The Earth ◽  
Third Stage ◽  
The Dead

This article is a inquiry about how Barrès (1862-1923) handles the religious rite of pilgrimage. Barrès stages in his writings three successive forms of pilgrimage, revealing what is sacred to him at different times. The pilgrimage to a museum or to the birthplace of an artist is typical for the egotism and the humanism of the young Barrès, expressed in the Cult of the Self (1888-1891). After his conversion to nationalism, Barrès tries to unite the sons of France and to instill in them a solemn reverence for “the earth and the dead” ; for that purpose he encourages in French Amities (1903) pilgrimages to historical places of national importance (battlefields; birthplace of Joan of Arc), building what Nora later called the Realms of Memory. The third stage of Barrès’ intellectual evolution is exemplified by The Sacred Hill (1913). In this book the writer celebrates the places where “the Spirit blows”, and proves open to a large scale of spiritual forces, reaching back to paganism and forward to integrative syncretism, which aims at unifying “the entire realm of the sacred”.

scholarly journals BiPSim: a flexible and generic stochastic simulator for polymerization processes

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Stephan Fischer ◽  
Marc Dinh ◽  
Vincent Henry ◽  
Philippe Robert ◽  
Anne Goelzer ◽  
...  
Keyword(s):  
Large Scale ◽  
Stochastic Simulation Algorithm ◽  
Specific Information ◽  
Whole Cell ◽  
Simulation Speed ◽  
Genome Wide ◽  
Cell Simulation ◽  
Stochastic Simulator ◽  
Modeling Formalisms ◽  
Stochastic Phenomena

AbstractDetailed whole-cell modeling requires an integration of heterogeneous cell processes having different modeling formalisms, for which whole-cell simulation could remain tractable. Here, we introduce BiPSim, an open-source stochastic simulator of template-based polymerization processes, such as replication, transcription and translation. BiPSim combines an efficient abstract representation of reactions and a constant-time implementation of the Gillespie’s Stochastic Simulation Algorithm (SSA) with respect to reactions, which makes it highly efficient to simulate large-scale polymerization processes stochastically. Moreover, multi-level descriptions of polymerization processes can be handled simultaneously, allowing the user to tune a trade-off between simulation speed and model granularity. We evaluated the performance of BiPSim by simulating genome-wide gene expression in bacteria for multiple levels of granularity. Finally, since no cell-type specific information is hard-coded in the simulator, models can easily be adapted to other organismal species. We expect that BiPSim should open new perspectives for the genome-wide simulation of stochastic phenomena in biology.

scholarly journals Rapid Spread of the SARS-CoV-2 Variant of Concern 202012/01 in Southern Italy (December 2020–March 2021)

2021 ◽  
Vol 18 (9) ◽  
pp. 4766
Author(s):  
Daniela Loconsole ◽  
Francesca Centrone ◽  
Caterina Morcavallo ◽  
Silvia Campanella ◽  
Anna Sallustio ◽  
...  
Keyword(s):  
Clinical Characteristics ◽  
Large Scale ◽  
Southern Italy ◽  
Whole Genome ◽  
Third Wave ◽  
Gene Target ◽  
The Third ◽  
Rapid Spread ◽  
Pharmaceutical Interventions ◽  
Over Time

Epidemiological and virological studies have revealed that SARS-CoV-2 variants of concern (VOCs) are emerging globally, including in Europe. The aim of this study was to evaluate the spread of B.1.1.7-lineage SARS-CoV-2 in southern Italy from December 2020–March 2021 through the detection of the S gene target failure (SGTF), which could be considered a robust proxy of VOC B.1.1.7. SGTF was assessed on 3075 samples from week 52/2020 to week 10/2021. A subset of positive samples identified in the Apulia region during the study period was subjected to whole-genome sequencing (WGS). A descriptive and statistical analysis of the demographic and clinical characteristics of cases according to SGTF status was performed. Overall, 20.2% of samples showed SGTF; 155 strains were confirmed as VOC 202012/01 by WGS. The proportion of SGTF-positive samples rapidly increased over time, reaching 69.2% in week 10/2021. SGTF-positive cases were more likely to be symptomatic and to result in hospitalization (p < 0.0001). Despite the implementation of large-scale non-pharmaceutical interventions (NPIs), such as the closure of schools and local lockdowns, a rapid spread of VOC 202012/01 was observed in southern Italy. Strengthened NPIs and rapid vaccine deployment, first among priority groups and then among the general population, are crucial both to contain the spread of VOC 202012/01 and to flatten the curve of the third wave.

scholarly journals Control method for the stable operation of distributed inverters following the introduction of large-scale renewable energy to a remote island grid

Clean Energy ◽  
2021 ◽  
Vol 5 (2) ◽  
pp. 196-207
Author(s):  
Shoichi Sato ◽  
Yasuhiro Noro
Keyword(s):  
Renewable Energy ◽  
Large Scale ◽  
Control Method ◽  
Synchronous Generator ◽  
Stable Operation ◽  
Battery Energy Storage Systems ◽  
Simulation Results ◽  
Battery Energy ◽  
Systems Simulation ◽  
Different Characteristics

Abstract The introduction of large-scale renewable energy requires a control system that can operate multiple distributed inverters in a stable way. This study proposes an inverter control method that uses information corresponding to the inertia of the synchronous generator to coordinate the operation of battery energy storage systems. Simulation results for a system with multiple inverters applying the control method are presented. Various faults such as line-to-line short circuits and three-phase line-to-ground faults were simulated. Two fault points with different characteristics were compared. The voltage, frequency and active power quickly returned to their steady-state values after the fault was eliminated. From the obtained simulation results, it was verified that our control method can be operated stably against various faults.

scholarly journals I višap armeni. Appunti per una storia della ricezione

2020 ◽  
Author(s):  
Alessandra Gilibert
Keyword(s):  
Middle Ages ◽  
Large Scale ◽  
South Caucasus ◽  
Political Messages ◽  
Complex Sequence ◽  
The Third ◽  
Third Millennium ◽  
Third Millennium Bce ◽  
History Of ◽  
Unknown Point

Vishaps are large-scale prehistoric stelae decorated with animal reliefs, erected at secluded mountain locations of the South Caucasus. This paper focuses on the vishaps of modern Armenia and traces their history of re-use and manipulations, from the end of the third millennium BCE to the Middle Ages. Since their creation at an unknown point in time before 2100 BCE, vishaps functioned as symbolic anchors for the creation and transmission of religious and political messages: they were torn down, buried, re-worked, re-erected, transformed and used as a surface for graffiti. This complex sequence of re-contextualisations underscores the primacy of mountains as political arenas for the negotiation of religious and ritual meaning.

scholarly journals The spatial allocation of population: a review of large-scale gridded population data products and their fitness for use

2019 ◽  
Vol 11 (3) ◽  
pp. 1385-1409 ◽  
Author(s):  
Stefan Leyk ◽  
Andrea E. Gaughan ◽  
Susana B. Adamo ◽  
Alex de Sherbinin ◽  
Deborah Balk ◽  
...  
Keyword(s):  
Large Scale ◽  
Population Data ◽  
Disaster Risk ◽  
Spatial Allocation ◽  
Quality Aspects ◽  
Data Products ◽  
Methodological Approaches ◽  
Different Characteristics ◽  
Population Counts ◽  
Relative Quality

Abstract. Population data represent an essential component in studies focusing on human–nature interrelationships, disaster risk assessment and environmental health. Several recent efforts have produced global- and continental-extent gridded population data which are becoming increasingly popular among various research communities. However, these data products, which are of very different characteristics and based on different modeling assumptions, have never been systematically reviewed and compared, which may impede their appropriate use. This article fills this gap and presents, compares and discusses a set of large-scale (global and continental) gridded datasets representing population counts or densities. It focuses on data properties, methodological approaches and relative quality aspects that are important to fully understand the characteristics of the data with regard to the intended uses. Written by the data producers and members of the user community, through the lens of the “fitness for use” concept, the aim of this paper is to provide potential data users with the knowledge base needed to make informed decisions about the appropriateness of the data products available in relation to the target application and for critical analysis.

scholarly journals Natural Leaders: Some interlocutors elicit greater convergence across conversations and across characteristics

2020 ◽  
Author(s):  
Uriel Cohen Priva ◽  
Chelsea Sanker
Keyword(s):  
Individual Differences ◽  
Large Scale ◽  
Social Aspects ◽  
Large Collection ◽  
Human Communication ◽  
Large Scale Study ◽  
Different Characteristics

Are there natural followers in human communication, speakers who consistently converge more than others? Similarly, are there natural leaders, speakers with whom others converge more? Are such tendencies consistent across different linguistic characteristics? We use the Switchboard Corpus, a large collection of telephone conversations, to perform a large-scale study of convergence of speakers in multiple conversations with different interlocutors, across six linguistic characteristics. Having data from each speaker in several conversations makes it possible to investigate whether there are individual differences in likelihood to converge, among speakers (more or less likely to converge), and among interlocutors (more or less likely to elicit convergence). We only find evidence for individual differences by interlocutor, not by speaker; this shows that there are natural leaders, who elicit greater degrees of convergence than others, across different characteristics and different conversations. The absence of a similar finding for natural followers, speakers who converge more than others, suggests that the role of social aspects in mediating convergence is stronger than that of putative individual differences in propensity to converge, or that such propensities are characteristic-specific.

Failure tests on full-scale models of grout laminated wood decks

2004 ◽  
Vol 31 (1) ◽  
pp. 133-145 ◽  
Author(s):  
Aftab A Mufti ◽  
Baidar Bakht ◽  
Dagmar Svecova ◽  
Vidyadhar Limaye
Keyword(s):  
Load Distribution ◽  
Full Scale ◽  
Bottom Surface ◽  
Distribution Characteristics ◽  
Flat Bottom ◽  
The Third ◽  
Scale Models ◽  
Lower Load ◽  
Load Tests ◽  
The University

Grout laminated wood decks (GLWDs), representing the third generation of stressed wood decks, comprise either laminates or logs trimmed to obtain two parallel faces. The logs or laminates, running along the span, are held together by means of transverse internal grout cylinders that may be in either compression or tension. Two full-scale models of GLWD were constructed at Dalhousie University, Halifax, one with grout cylinders in compression and the other with the cylinders in tension. Service load tests conducted in Halifax showed that the former deck had better load distribution characteristics. Two years after the tests in Halifax, the models were shipped to The University of Manitoba in Winnipeg, where they were tested to failure under a central patch load. Because of miscommunication with the supplier, the logs of the GLWD with grout cylinders in compression were also trimmed to the third face that was kept at the bottom of the deck. The failure tests showed that despite its superior load distribution characteristics, the deck with grout cylinders in compression failed at a significantly lower load than the GLWD with cylinders in tension. It is argued that a planar surface in the logs at the flexural tension face not only reduces their flexural stiffness but also brings the defects of wood to the surface with maximum stress. The deck with the flat bottom surface underwent tension failure of the most heavily loaded logs, whereas the deck with the intact round surface of the logs at both top and bottom failed by horizontal splitting of all the logs.Key words: articulated plate, bridge deck, grout laminated deck, orthotropic plate, timber.

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