Stationarization and Multithermalization in spin glasses

We develop further the study of a system in contact with a multibath having different temperatures at widely separated timescales. We consider those systems that do not thermalize in finite times when in contact with an ordinary bath but may do so in contact with a multibath. Thermodynamic integration is possible, thus allowing one to recover the stationary distribution on the basis of measurements performed in a `multi-reversible' transformation. We show that following such a protocol the system is at each step described by a generalization of the Boltzmann-Gibbs distribution, that has been studied in the past. Guerra's bound interpolation scheme for spin-glasses is closely related to this: by translating it into a dynamical setting, we show how it may actually be implemented in practice. The phase diagram plane of temperature vs ``number of replicas", long studied in spin- glasses, in our approach becomes simply that of the two temperatures the system is in contact with. We suggest that this representation may be used to directly compare phenomenological and mean-field inspired models. Finally, we show how an approximate out of equilibrium probability distribution may be inferred experimentally on the basis of measurements along an almost reversible transformation.

Preventive Repression: Two Types of Moral Hazard

Authoritarian leaders maintain their grip on power primarily through preventive repression, routinely exercised by specialized security agencies with the aim of preventing any opponents from organizing and threatening their power. We develop a formal model to analyze the moral hazard problems inherent in the principal-agent relationship between rulers and their security agents in charge of preventive repression. The model distinguishes two types of moral hazard: “politics,” through which the security agents can exert political influence to increase their payoff by decreasing the ruler’s rents from power, and “corruption,” through which the agents can increase their payoff by engaging in rent-seeking activities that do not decrease the ruler’s rents from power. The surprising conclusion is that both the ruler and the security agent are better off when the only moral hazard problem available is politics rather than when the agent can choose between politics and corruption. We also show that the equilibrium probability of ruler’s survival in power is higher when politics is the only moral hazard available to the agent. These findings lead to our central conclusion that opportunities for corruption undermine authoritarian rule by distorting the incentives of the security agencies tasked with preventing potential threats to an authoritarian ruler’s grip on power.

Allocation schemes of resources with downgrading

We consider a server with large capacity delivering video files encoded in various resolutions. We assume that the system is under saturation in the sense that the total demand exceeds the server capacity C. In such a case, requests may be rejected. For the policies considered in this paper, instead of rejecting a video request, it is downgraded. When the occupancy of the server is above some value C0 < C, the server delivers the video at a minimal bit rate. The quantity C0 is the bit rate adaptation threshold. For these policies, request blocking is thus replaced with bit rate adaptation. Under the assumptions of Poisson request arrivals and exponential service times, we show that, by rescaling the system, a process associated with the occupancy of the server converges to some limiting process whose invariant distribution is computed explicitly. This allows us to derive an asymptotic expression of the key performance measure of such a policy, namely the equilibrium probability that a request is transmitted at requested bitrate. Numerical applications of these results are presented.

A statics-dynamics equivalence through the fluctuation–dissipation ratio provides a window into the spin-glass phase from nonequilibrium measurements

We have performed a very accurate computation of the nonequilibrium fluctuation–dissipation ratio for the 3D Edwards–Anderson Ising spin glass, by means of large-scale simulations on the special-purpose computers Janus and Janus II. This ratio (computed for finite times on very large, effectively infinite, systems) is compared with the equilibrium probability distribution of the spin overlap for finite sizes. Our main result is a quantitative statics-dynamics dictionary, which could allow the experimental exploration of important features of the spin-glass phase without requiring uncontrollable extrapolations to infinite times or system sizes.

Combating Smuggling: What Games We Are Playing: An Indonesian Case Study

Intuitively, a person’s behavioral tendency to corrupt seems to follow several incentives that bound with the outcomes. But changes in outcomes’ payoffs do not always directly affect to person behavior. In games with mixed equilibrium presences, probability of actions taken by other parties (in this paper, “to inspect” and “do not inspect”) will alter a person tendency whether “to comply” or “to cheat”, as shown in garment smuggling case in Indonesia. Game theoretic concepts were employed in this paper to perform framework for analysis in describing the actions of interdependent agents. When the game has mixed equilibrium, probability of one player to take one strategic action does not depend on the opponent’s payoffs (i.e. maximum penalty). What does change is the probability of the opponent’s strategic actions.

Some Characterization Results on Dynamic Cumulative Residual Tsallis Entropy

We propose a generalized cumulative residual information measure based on Tsallis entropy and its dynamic version. We study the characterizations of the proposed information measure and define new classes of life distributions based on this measure. Some applications are provided in relation to weighted and equilibrium probability models. Finally the empirical cumulative Tsallis entropy is proposed to estimate the new information measure.