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Planetary Radio Interferometry and Doppler Experiment (PRIDE) of the JUICE mission
Authors:
Leonid I. Gurvits,
Giuseppe Cimo,
Dominic Dirkx,
Vidhya Pallichadath,
Alexander Akins,
Nicolas Altobelli,
Tatiana M. Bocanegra-Bahamon,
Stephanie M. Cazaux,
Patrick Charlot,
Dmitry A. Duev,
Marie S. Fayolle,
Judit Fogasy,
Sandor Frey,
Valery Lainey,
Guifre Molera Calves,
Krisztina Perger,
Sergey V. Pogrebenko,
N. Masdiana Md Said,
Claire Vallat,
Bert L. A. Vermeersen,
Pieter N. A. M. Visser,
Kuo-Nung Wang,
Konrad Willner
Abstract:
Planetary Radio Interferometry and Doppler Experiment (PRIDE) is a multi-purpose experimental technique aimed at enhancing the science return of planetary missions. The technique exploits the science payload and spacecraft service systems without requiring a dedicated onboard instrumentation or imposing on the existing instrumentation any special for PRIDE requirements. PRIDE is based on the near-…
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Planetary Radio Interferometry and Doppler Experiment (PRIDE) is a multi-purpose experimental technique aimed at enhancing the science return of planetary missions. The technique exploits the science payload and spacecraft service systems without requiring a dedicated onboard instrumentation or imposing on the existing instrumentation any special for PRIDE requirements. PRIDE is based on the near-field phase-referencing Very Long Baseline Interferometry (VLBI) and evaluation of the Doppler shift of the radio signal transmitted by spacecraft by observing it with multiple Earth-based radio telescopes. The methodology of PRIDE has been developed initially at the Joint Institute for VLBI ERIC (JIVE) for tracking the ESA's Huygens Probe during its descent in the atmosphere of Titan in 2005. From that point on, the technique has been demonstrated for various planetary and other space science missions. The estimates of lateral position of the target spacecraft are done using the phase-referencing VLBI technique. Together with radial Doppler estimates, these observables can be used for a variety of applications, including improving the knowledge of the spacecraft state vector. The PRIDE measurements can be applied to a broad scope of research fields including studies of atmospheres through the use of radio occultations, the improvement of planetary and satellite ephemerides, as well as gravity field parameters and other geodetic properties of interest, and estimations of interplanetary plasma properties. This paper presents the implementation of PRIDE as a component of the ESA's Jupiter Icy Moons Explorer (JUICE) mission.
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Submitted 28 November, 2023; v1 submitted 7 November, 2023;
originally announced November 2023.
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Visual Analysis of Displacement Processes in Porous Media using Spatio-Temporal Flow Graphs
Authors:
Alexander Straub,
Nikolaos Karadimitriou,
Guido Reina,
Steffen Frey,
Holger Steeb,
Thomas Ertl
Abstract:
We developed a new approach comprised of different visualizations for the comparative spatio-temporal analysis of displacement processes in porous media. We aim to analyze and compare ensemble datasets from experiments to gain insight into the influence of different parameters on fluid flow. To capture the displacement of a defending fluid by an invading fluid, we first condense an input image ser…
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We developed a new approach comprised of different visualizations for the comparative spatio-temporal analysis of displacement processes in porous media. We aim to analyze and compare ensemble datasets from experiments to gain insight into the influence of different parameters on fluid flow. To capture the displacement of a defending fluid by an invading fluid, we first condense an input image series to a single time map. From this map, we generate a spatio-temporal flow graph covering the whole process. This graph is further simplified to only reflect topological changes in the movement of the invading fluid. Our interactive tools allow the visual analysis of these processes by visualizing the graph structure and the context of the experimental setup, as well as by providing charts for multiple metrics. We apply our approach to analyze and compare ensemble datasets jointly with domain experts, where we vary either fluid properties or the solid structure of the porous medium. We finally report the generated insights from the domain experts and discuss our contribution's advantages, generality, and limitations.
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Submitted 13 November, 2023; v1 submitted 27 July, 2023;
originally announced July 2023.
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Quantifying the selective, stochastic, and complementary drivers of the institutional evolution in online communities
Authors:
Qiankun Zhong,
Seth Frey,
Martin Hilbert
Abstract:
Institutions and cultures evolve adaptively in response to the current environmental incentives, usually. But sometimes institutional change is due to stochastic drives beyond current fitness, including drift, path dependency, blind imitation, and complementary cooperation in fluctuating environments. Disentangling the selective and stochastic components of social system change enables us to ident…
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Institutions and cultures evolve adaptively in response to the current environmental incentives, usually. But sometimes institutional change is due to stochastic drives beyond current fitness, including drift, path dependency, blind imitation, and complementary cooperation in fluctuating environments. Disentangling the selective and stochastic components of social system change enables us to identify the key features to organizational development in the long run. Evolutionary approaches provide organizational science abundant theories to demonstrate organizational evolution by tracking particular beneficial or harmful features. We measure these different drivers empirically in institutional evolution among 20,000 Minecraft communities with the help of two of the most applied evolutionary models, the Price equation and the bet-hedging model. As a result, we find strong selection pressure on administrative rules and information rules, suggesting that their positive correlation with community fitness is the main reason for their frequency change. We also find that stochastic drives decrease the average frequency of administrative rules. The result makes sense when explained in light of evolutionary bet-hedging. We show through the bet-hedging result that institutional diversity contributes to the growth and stability of rules related to information, communication, and economic behaviors.
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Submitted 21 August, 2022; v1 submitted 26 April, 2022;
originally announced April 2022.
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Visual Analysis of Two-Phase Flow Displacement Processes in Porous Media
Authors:
Steffen Frey,
Stefan Scheller,
Nikolaos Karadimitriou,
Dongwon Lee,
Guido Reina,
Holger Steeb,
Thomas Ertl
Abstract:
We present the visual analysis of our novel parameter study of porous media experiments, focusing on gaining a better understanding of drainage processes on the micro-scale. We analyze the temporal evolution of extracted characteristic values, and discuss how to directly compare experiments that exhibit processes at different temporal scales due to varying boundary and physical conditions. To enab…
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We present the visual analysis of our novel parameter study of porous media experiments, focusing on gaining a better understanding of drainage processes on the micro-scale. We analyze the temporal evolution of extracted characteristic values, and discuss how to directly compare experiments that exhibit processes at different temporal scales due to varying boundary and physical conditions. To enable spatio-temporal analysis, we introduce a new abstract visual representation showing which paths through the porous media were occupied to what extent, e.g., allowing for classification into viscous and capillary regimes. This joint work of porous media experts and visualization researchers yields new insights regarding immiscible two-phase flow on the micro-scale toward the overarching goal of characterizing flow based on boundary conditions and physical fluid properties.
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Submitted 2 April, 2021; v1 submitted 22 March, 2021;
originally announced March 2021.
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Super-teams or fair leagues? Parity policies by powerful regulators don't prevent capture
Authors:
Adam Sawyer,
Seth Frey
Abstract:
Much of modern society is founded on orchestrating institutions that produce social goods by fostering motivated teams, pitting them against each other, and distributing the fruits of the arms races that ensue. However, even when the "market maker" is willing and able to maintain parity between teams, it may fail to maintain a level playing field, as some teams acquire enough advantage within the…
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Much of modern society is founded on orchestrating institutions that produce social goods by fostering motivated teams, pitting them against each other, and distributing the fruits of the arms races that ensue. However, even when the "market maker" is willing and able to maintain parity between teams, it may fail to maintain a level playing field, as some teams acquire enough advantage within the system to gain influence over it and institutionalize their advantage. Using outcomes of over 60,000 games from four professional basketball leagues and more than 100 years' worth of seasons, we compute the evolving rate of transitivity violations (A>B, B>C, but C>A) to measure the ability of leagues to maintain parity between teams, and support the efficient generation and distribution of innovation. Comparing against a baseline of randomly permuted outcomes, we find that basketball has become less competitive over time, suggesting that teams diverge in performance, and reflecting a possible failure of market makers to tame their overpowered teams. Our results suggest that rich-get-richer dynamics are so pernicious that they can even emerge under the watch of a powerful administrator that is motivated to prevent them.
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Submitted 21 September, 2020; v1 submitted 21 September, 2020;
originally announced September 2020.
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A dynamic over games drives selfish agents to win-win outcomes
Authors:
Seth Frey,
Curtis Atkisson
Abstract:
Understanding the evolution of human social systems requires flexible formalisms for the emergence of institutions. Although game theory is normally used to model interactions individually, larger spaces of games can be helpful for modeling how interactions change. We introduce a framework for modeling "institutional evolution," how individuals change the games they are placed in. We contrast this…
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Understanding the evolution of human social systems requires flexible formalisms for the emergence of institutions. Although game theory is normally used to model interactions individually, larger spaces of games can be helpful for modeling how interactions change. We introduce a framework for modeling "institutional evolution," how individuals change the games they are placed in. We contrast this with the more familiar within-game "behavioral evolution". Starting from an initial game, agents trace trajectories through game space by repeatedly navigating to more preferable games until they converge on attractor games that are preferred to all others. Agents choose between games on the basis of their "institutional preferences," which define between-game comparisons in terms of game-level features such as stability, fairness, and efficiency. Computing institutional change trajectories over the two-player space, we find that the attractors of self-interested economic agents over-represent fairness by 100% relative to baseline, even though those agents are indifferent to fairness. This seems to occur because fairness, as a game feature, co-occurs with the self-serving features these agents do prefer. We thus present institutional evolution as a mechanism for encouraging the spontaneous emergence of cooperation among inherently selfish agents. We then extend these findings beyond two players, and to two other types of evolutionary agent: the relative fitness maximizing agent of evolutionary game theory (who maximizes inequality), and the relative group fitness maximizing agent of multi-level/group selection theory (who minimizes inequality). This work provides a flexible, testable formalism for modeling the interdependencies of behavioral and institutional evolutionary processes.
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Submitted 15 July, 2019;
originally announced July 2019.
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Cognitive mechanisms for human flocking dynamics
Authors:
Seth Frey,
Robert L. Goldstone
Abstract:
Low-level "adaptive" and higher-level "sophisticated" human reasoning processes have been proposed to play opposing roles in the emergence of unpredictable collective behaviors like crowd panics, traffic jams, and market bubbles. While adaptive processes are ubiquitous in mechanistic theories of emergent social complexity, complementary theories understand incentives, education, and other induceme…
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Low-level "adaptive" and higher-level "sophisticated" human reasoning processes have been proposed to play opposing roles in the emergence of unpredictable collective behaviors like crowd panics, traffic jams, and market bubbles. While adaptive processes are ubiquitous in mechanistic theories of emergent social complexity, complementary theories understand incentives, education, and other inducements to rationality as able to suppress such outcomes.
We show in a series of laboratory experiments that, rather than suppressing complex social dynamics, sophisticated reasoning processes can support them. Our experiments elicit flocking behavior in groups and show that it is driven by the human ability to recursively anticipate the reasoning of others. We identify this sophisticated flocking in three different games---the Beauty Pageant, Mod Game, and Runway Game---across which game theory predicts no formal similarity. The persistence of sophisticated flocking across unrelated game types not only speaks to the phenomenon's robustness, it also suggests that people are treating three supposedly different decision settings as conceptually similar, implicating a second sophisticated cognitive ability: human concept formation. We also find in participants' underlying reasoning that the number of recursions they perform is limited not by any individual's cognitive abilities, but by a social norm that emerges during flocking.
By implicating both recursive reasoning and concept formation in complex dynamics, we support interdisciplinary perspectives that emergent complexity is typical of even the most intelligent populations and carefully designed social systems.
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Submitted 7 June, 2017; v1 submitted 15 June, 2015;
originally announced June 2015.
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Cyclic game dynamics driven by iterated reasoning
Authors:
Seth Frey,
Robert L. Goldstone
Abstract:
Recent theories from complexity science argue that complex dynamics are ubiquitous in social and economic systems. These claims emerge from the analysis of individually simple agents whose collective behavior is surprisingly complicated. However, economists have argued that iterated reasoning--what you think I think you think--will suppress complex dynamics by stabilizing or accelerating convergen…
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Recent theories from complexity science argue that complex dynamics are ubiquitous in social and economic systems. These claims emerge from the analysis of individually simple agents whose collective behavior is surprisingly complicated. However, economists have argued that iterated reasoning--what you think I think you think--will suppress complex dynamics by stabilizing or accelerating convergence to Nash equilibrium. We report stable and efficient periodic behavior in human groups playing the Mod Game, a multi-player game similar to Rock-Paper-Scissors. The game rewards subjects for thinking exactly one step ahead of others in their group. Groups that play this game exhibit cycles that are inconsistent with any fixed-point solution concept. These cycles are driven by a "hopping" behavior that is consistent with other accounts of iterated reasoning: agents are constrained to about two steps of iterated reasoning and learn an additional one-half step with each session. If higher-order reasoning can be complicit in complex emergent dynamics, then cyclic and chaotic patterns may be endogenous features of real-world social and economic systems.
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Submitted 16 January, 2013; v1 submitted 26 June, 2012;
originally announced June 2012.