scholarly journals Report of the IAU WGAS Sub-group on Issues on Time

1995 ◽  
Vol 10 ◽  
pp. 193-196
Author(s):  
P.K. Seidelmann
Keyword(s):  
Time Scales ◽  
Working Group ◽  
Reference Systems ◽  
Coordinate Time ◽  
Dynamical Time ◽  
Different Time Scales

Included in the nine adopted recommendations of the IAU Working Group on Reference Systems (Hughes, et. al., in 1991), were recommendations for the introduction of Geocentric Coordinate Time (TCG) and Barycentric CoordinateTime (TCB), the renaming of the Terrestrial Dynamical Time (TDT) as Terrestrial Time (TT), and the approval to continue the use of Barycentric Dynamical Time (TDB) when that is desirable. The relationships between these different time scales and the reason for their introduction was given by Seidelmann and Fukushima (1992). Since it was recognized that there were some unresolved issues as a result of these recommendations, a subcommittee of the Working Group on Astronomical Standards was established for Issues on Time.

scholarly journals Presentation of WGRS Recommendations I to V

1992 ◽  
Vol 9 ◽  
pp. 116-119
Author(s):  
B. Guinot
Keyword(s):  
Time Scales ◽  
Space Time ◽  
Point Of View ◽  
Reference Systems ◽  
Global Approach ◽  
Dynamical Time ◽  
Time Standards ◽  
Primary Mission ◽  
Relativistic Framework ◽  
Atomic Time

I start by general remarks on the background of the recommendations on space-time references which are submitted to you.The need to consider time scales in a relativistic framework appeared more than 20 years age following the progress of atomic time standards. After long discussions, this led the IAU to define, In 1976, time scales which were designated, In 1979, as Terrestrial Dynamical Time (TDT) and Barycentric Dynamical Time (TDB). But soon afterwards difficulties in the interpretation of the definitions of TDT and TDB arose. It appeared that the source of these difficulties was the lack of a global approach to space-time reference systems. This point of view, first voiced by J. Lieske, gained acceptance. At the very beginning of the work of the WGRS Sub-Groups on Frames and Origins (SGFO) and on Time (SGT), It became clear the the primary mission of the SGFO and SGT was to jointly prepare general recommendations on space-time references on which they could base their specific recommendations.

Agent-Based Computational Model

2017 ◽  
Author(s):  
Joshua M. Epstein
Keyword(s):  
Computational Model ◽  
Bounded Rationality ◽  
Time Scales ◽  
Spatially Explicit ◽  
Agent Based ◽  
Affective Component ◽  
Elementary Type ◽  
Social Component ◽  
Different Time Scales

This part describes the agent-based and computational model for Agent_Zero and demonstrates its capacity for generative minimalism. It first explains the replicability of the model before offering an interpretation of the model by imagining a guerilla war like Vietnam, Afghanistan, or Iraq, where events transpire on a 2-D population of contiguous yellow patches. Each patch is occupied by a single stationary indigenous agent, which has two possible states: inactive and active. The discussion then turns to Agent_Zero's affective component and an elementary type of bounded rationality, as well as its social component, with particular emphasis on disposition, action, and pseudocode. Computational parables are then presented, including a parable relating to the slaughter of innocents through dispositional contagion. This part also shows how the model can capture three spatially explicit examples in which affect and probability change on different time scales.

Green markets integration in different time scales: A regional analysis

2021 ◽  
Vol 98 ◽  
pp. 105254 ◽  
Author(s):  
Christian Urom ◽  
Hela Mzoughi ◽  
Ilyes Abid ◽  
Mariem Brahim
Keyword(s):  
Time Scales ◽  
Regional Analysis ◽  
Different Time Scales

scholarly journals Measuring chromosome dynamics on different time scales using resolvases with varying half-lives

2005 ◽  
Vol 56 (4) ◽  
pp. 1049-1061 ◽  
Author(s):  
Richard A. Stein ◽  
Shuang Deng ◽  
N. Patrick Higgins
Keyword(s):  
Time Scales ◽  
Chromosome Dynamics ◽  
Different Time Scales

scholarly journals Reservoir ecological operation considering outflow variations across different time scales

2021 ◽  
Vol 125 ◽  
pp. 107582 ◽  
Author(s):  
Yibo Wang ◽  
Pan Liu ◽  
Ming Dou ◽  
He Li ◽  
Bo Ming ◽  
...  
Keyword(s):  
Time Scales ◽  
Different Time Scales

scholarly journals Dynamical time scales of friction dynamics in active microrheology of a model glass

Soft Matter ◽  
2021 ◽  
Author(s):  
Ata Madanchi ◽  
Ji Woong Yu ◽  
Mohamad Reza Rahimi Tabar ◽  
Won Bo Lee ◽  
S. E. E. Rahbari
Keyword(s):  
Time Scales ◽  
Supercooled Liquids ◽  
Model Glass ◽  
Heterogeneous Structures ◽  
Dynamical Time ◽  
Friction Dynamics

Owing to the local/heterogeneous structures in supercooled liquids, after several decades of research, it is now clear that supercooled liquids are structurally different from their conventional liquid counterparts. Accordingly, an...

scholarly journals Stellar noise and planet detection. I. Oscillations, granulation and sun-like spots

2010 ◽  
Vol 6 (S276) ◽  
pp. 527-529
Author(s):  
Xavier Dumusque ◽  
Nuno C. Santos ◽  
Stéphane Udry ◽  
Cristophe Lovis ◽  
Xavier Bonfils
Keyword(s):  
Radial Velocity ◽  
Time Scales ◽  
High Precision ◽  
Habitable Zone ◽  
Planet Detection ◽  
Solar Type ◽  
Physical Phenomena ◽  
Instrumental Precision ◽  
Observational Strategy ◽  
Different Time Scales

AbstractSpectrographs like HARPS can now reach a sub-ms−1 precision in radial-velocity (RV) (Pepe & Lovis 2008). At this level of accuracy, we start to be confronted with stellar noise produced by 3 different physical phenomena: oscillations, granulation phenomena (granulation, meso- and super-granulation) and activity. On solar type stars, these 3 types of perturbation can induce ms−1 RV variation, but on different time scales: 3 to 15 minutes for oscillations, 15 minutes to 1.5 days for granulation phenomena and 10 to 50 days for activity. The high precision observational strategy used on HARPS, 1 measure per night of 15 minutes, on 10 consecutive days each month, is optimized, due to a long exposure time, to average out the noise coming from oscillations (Dumusque et al. 2011a) but not to reduce the noise coming from granulation and activity (Dumusque et al. 2011a and Dumusque et al. 2011b). The smallest planets found with this strategy (Mayor et al. 2009) seems to be at the limit of the actual observational strategy and not at the limit of the instrumental precision. To be able to find Earth mass planets in the habitable zone of solar-type stars (200 days for a K0 dwarf), new observational strategies, averaging out simultaneously all type of stellar noise, are required.

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