14,016 research outputs found

    Relaxing the symmetry assumption in participation games: A specification test for cluster heterogeneity

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    Published online: 05 April 2023. OnlinePublWe propose a novel approach to check whether individual behaviour in binary-choice participation games is consistent with the restrictions imposed by symmetric models. This approach allows in particular an assessment of how much cluster-heterogeneity a symmetric model can tolerate to remain consistent with its behavioural restrictions. We assess our approach with data from market-entry experiments which we analyse through the lens of ‘Exploration versus Exploration’ (EvE, which is equivalent to Logit-QRE) or of Impulse Balance Equilibrium (IBE). We find that when the symmetry assumption is imposed, both models are typically rejected when assuming pooled data and IBE yields more data-consistent estimates than EvE, i.e., IBE’s estimates of session and pooled data are more consistent than those of EvE. When relaxing symmetry, EvE (IBE) is rejected for 17% (42%) of the time. Although both models support cluster-heterogeneity, IBE is much less likely to yield over-parametrised specifications and insignificant estimates so it outperforms EvE in accommodating a model-consistent cluster-heterogeneity. The use of regularisation procedures in the estimations partially addresses EvE’s shortcomings but leaves our overall conclusions unchanged.Alan Kirman, François Laisney, Paul Pezanis, Christo

    Thermophoresis of electrolyte solutions and protein-ligand systems

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    Thermophoresis or thermodiffusion is the mass transport driven by a temperature gradient. This thesis focuses on the thermophoretic motion of ionic compounds in a biological context and is motivated by a practical application, in which thermodiffusion is used to monitor protein-ligand reactions. Proteins are complex molecules containing non-ionic and ionic groups. While recent studies of non-ionic compounds found a strong correlation between thermodiffusion and hydration, it is unclear how this correlation changes when molecules are charged. To separate ionic from non-ionic contributions, it is reasonable to look first into the thermophoretic motion of simple salts without large organic side groups and to study in the next step complex protein-ligand systems, which typically contain hydrophobic and hydrophilic groups. The systematic studies of aqueous solutions of simple salts should reveal differences between ionic and non-ionic systems and should give further information about ion and ion specific effects. Due to the high complexity of protein-ligand systems, complementary methods should be used to gain a better understanding of the interactions between different components that are present in the system. This will help to understand how the thermophoretic behavior of the free protein differs from that of the protein-ligand complex formed. Study of the thermophoretic behavior of ionic systems indicates that several correlations, which were found for aqueous solutions of non-ionic solutes are no longer valid for ionic solutes. For non-ionic solutes hydrogen bonds primarily influence the thermophoretic behavior. In case of ionic solutes, although both electrostatic interactions and hydrogen bonds are present, it is found that thermophoretic behavior is influenced by electrostatic interactions. Focusing on the specific ion effects for ionic systems in the context of the Hofmeister series, a change of the anion is found to influence the thermophoretic behavior more than a change of the cation. Further, a correlation between thermophoretic behavior and hydrophilicity of the ionic solutes is found, which underlines the sensitivity of thermodiffusion to changes in hydration. Based on this sensitivity, a preliminary model is developed for describing the non-monotonous variation of Soret coefficient ST with concentration for aqueous solutions of alkali iodide salts. To study the thermodiffusion of binding reactions, we also use complementary methods such as Isothermal Titration Calorimetry (ITC) and a thermophoretic microfluidic cell. As systems, we have chosen EDTA-CaCl2 and protein-ligand systems (binding of Bovine Carbonic Anhydrase I (BCA I) with two aryl sulfonamide ligands). To gain deeper insight into the complex formation reactions thermophoretic data (non-equilibrium process) are compared with thermodynamic data (equilibrium process) to establish a mathematical relation between ST and Gibb’s free energy ΔG. For EDTA-CaCl2 and protein-ligand systems, the derived relation holds valid, which enables calculation of ΔG at a particular temperature from ST

    Machine Learning Meets Mental Training -- A Proof of Concept Applied to Memory Sports

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    This work aims to combine these two fields together by presenting a practical implementation of machine learning to the particular form of mental training that is the art of memory, taken in its competitive version called "Memory Sports". Such a fusion, on the one hand, strives to raise awareness about both realms, while on the other it seeks to encourage research in this mixed field as a way to, ultimately, drive forward the development of this seemingly underestimated sport.Comment: 75 pages, 47 figures, 2 tables, 26 code excerpt

    How to promote the hierarchical diagnosis and treatment system: A tripartite evolutionary game theory perspective

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    Due to the disorderly access to medical care and inefficient use of health resources, the advancement of the hierarchical diagnosis and treatment is more valued in promoting health system reform. Hence, this article integrates prospect theory into an evolutionary game model of the local government health departments, the medical institutions, and the patients in the system promotion of the hierarchical diagnosis and treatment. The simulation shows the specific influencing mechanism of the psychological perceived value of game subjects. Then by introducing the stochastic evolutionary game model, the system promotion under different medical cultures is also discussed in detail. The results indicate that for local government health departments, the amount and duration of financial subsidies are the key factors influencing the game system’s evolution. For medical institutions, participating in the hierarchical diagnosis and treatment system is relatively beneficial. For patients, the recovery rate in primary hospitals matters more than the cost of treatment. Changes in the risk sensitivity coefficient will cause the equilibrium of the game system to change. However, changes in the loss avoidance factor do not change the equilibrium and only have an impact on the speed of convergence. With the health departments’ intervention, patients in rural medical culture are more inclined to support the hierarchical diagnosis and treatment system than those in urban or town medical culture. Therefore, in order to promote the hierarchical diagnosis and treatment system, this article recommends that more attention should be paid to the regulatory role of health departments and the participation improvement of medical institutions and patients

    Game theoretic analysis of Citizens Broadband Radio Service

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    The Citizens Broadband Radio Service (CBRS) is a spectrum sharing framework on the 3.5 GHz tier with three priority tiers: the incumbents, priority commercial users (PAL), and general commercial users (GAA). Thus, commercial users compete for resources within the second and third priority tiers. The interaction between commercial providers and customers is complicated by the presence of the incumbents, who impact the availability of spectrum but bypass the market entirely. In particular, PAL customers are themselves subject to preemption even with the priority purchase. In this paper, we propose a game-theoretic framework to shed light into the equilibrium outcomes and the impact of the incumbents into these. We determine that there exist several possible equilibrium regions, including one with a unique mixed equilibrium which is stable in the evolutionary stable strategy sense, and others featuring unstable mixed equilibria and stable pure equilibria. We show that for fixed parameters, the maximum possible revenue a provider can obtain is associated with a stable equilibrium and is thus guaranteed. However, changes in incumbent behavior can result in phase changes which have a sizable impact on the maximum potential revenue.CNS-1908087 - National Science FoundationAccepted manuscrip

    Latin America in Times of Turbulence: Presidentialism under Stress

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    This book accounts for and analyses the latest developments in Latin American presidential democracies, with a special focus on political institutions. The stellar line-up of renowned scholars of Latin American politics and institutions from Latin America, Europe, and the United States offer new insights into how democratic institutions have operated within the critical context that marked the political and social life of the region in the last few years: the eruption of popular protest and discontent, the widespread distrust of political institutions, and, of course, the COVID-19 pandemic. Combining different methodological approaches, including cross-national studies, small-N studies, case studies, and quantitative and qualitative data, the contributions cluster around three themes: the problem with fixed terms and other features of presidentialism, inter-institutional relations and executive accountability, and old and new threats to democracy in these times of turmoil. The volume concludes with an assessment of the political consequences of the COVID-19 pandemic in Latin America. Beyond current scholars and students of comparative political scientists, Latin America in Times of Turbulence will be of great interest to a wide spectrum of readers interested in comparative systems of government, democracy studies, and Latin American politics more generally

    Modeling Travel Behavior in Mobility Systems with an Atomic Routing Game and Prospect Theory

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    In this paper, we present a game-theoretic modeling framework for studying the travel behavior in mobility systems, by incorporating prospect theory. As part of our motivation, we conducted an experiment in a scaled smart city to investigate the frequency of errors in actual and perceived probabilities of a highway route under free flow conditions. Based on these findings, we provide a game that captures how travelers distribute their traffic flows in a transportation network with splittable traffic, utilizing the Bureau of Public Roads function to establish the relationship between traffic flow and travel time cost. Given the inherent non-linearities, we propose a smooth approximation function that helps us estimate the prospect-theoretic cost functions. As part of our analysis, we characterize the best-fit parameters and derive an upper bound for the error. We then show a Nash Equilibrium existence. Finally, we present a numerical example and simulations to verify the theoretical results and demonstrate the effectiveness of our approximation.Comment: arXiv admin note: text overlap with arXiv:2202.0769

    Commitment Against Front Running Attacks

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    We provide a game-theoretic analysis of the problem of front-running attacks. We use it to distinguish attacks from legitimate competition among honest users for having their transactions included earlier in the block. We also use it to introduce an intuitive notion of the severity of front-running attacks. We then study a simple commit-reveal protocol and discuss its properties. This protocol has costs because it requires two messages and imposes a delay. However, we show that it prevents the most severe front-running attacks while preserving legitimate competition between users, guaranteeing that the earliest transaction in a block belongs to the honest user who values it the most. Furthermore, it reduces competition among attackers, which also benefits honest users

    Nash Equilibrium Existence without Convexity

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    In this paper, I prove the existence of a pure-strategy Nash equilibrium for a large class of games with nonconvex strategy spaces. Specifically, if each player's strategies form a compact, connected Euclidean neighborhood retract and if all best-response correspondences are null-homotopic, then the game has a pure-strategy Nash equilibrium. As an application, I show how this result can prove the fundamental theorem of algebra.Comment: 9 page
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