Thermodynamic Bounds on Efficiency for Systems with Broken Time-reversal Symmetry

We show that for systems with broken time-reversal symmetry the maximum efficiency and the efficiency at maximum power are both determined by two parameters: a "figure of merit" and an asymmetry parameter. In contrast to the time-symmetric case, the figure of merit is bounded from above; nevertheless the Carnot efficiency can be reached at lower and lower values of the figure of merit and far from the so-called strong coupling condition as the asymmetry parameter increases. Moreover, the Curzon-Ahlborn limit for efficiency at maximum power can be overcome within linear response. Finally, always within linear response, it is allowed to have simultaneously Carnot efficiency and non-zero power.Comment: Final version, 4 pages, 3 figure

The Thermodynamic Efficiency in Static and Dynamic Black Holes

We note that, in extended phase space the cosmological constant is a thermodynamic variable. In this paper, this cosmological constant lead us to consider a black hole as a heat engine. So, here we take advantage from holographic heat engine and study two kind of different black holes. We first investigate a static black hole (Dyonic BH) and consider the necessary condition to have high efficiency. Also we continue our investigation for dynamic black hole (rotating charged black hole) and study the effect of rotating parameter on the thermodynamic efficiency of holographic heat engine. We show that the rotating parameter has a more effective role than electric charge in thermodynamic efficiency

The Sharp Lower Bound of Asymptotic Efficiency of Estimators in the Zone of Moderate Deviation Probabilities

For the zone of moderate deviation probabilities the local asymptotic minimax lower bound of asymptotic efficiency of estimators is established. The estimation parameter is multidimensional. The lower bound admits the interpretation as the lower bound of asymptotic efficiency in confidence estimation

Efficient preconditioners for saddle point systems with trace constraints coupling 2D and 1D domains

We study preconditioners for a model problem describing the coupling of two elliptic subproblems posed over domains with different topological dimension by a parameter dependent constraint. A pair of parameter robust and efficient preconditioners is proposed and analyzed. Robustness and efficiency of the preconditioners is demonstrated by numerical experiments

Ancillarity-Sufficiency Interweaving Strategy (ASIS) for Boosting MCMC Estimation of Stochastic Volatility Models

Bayesian inference for stochastic volatility models using MCMC methods highly depends on actual parameter values in terms of sampling efficiency. While draws from the posterior utilizing the standard centered parameterization break down when the volatility of volatility parameter in the latent state equation is small, non-centered versions of the model show deficiencies for highly persistent latent variable series. The novel approach of ancillarity-sufficiency interweaving has recently been shown to aid in overcoming these issues for a broad class of multilevel models. In this paper, we demonstrate how such an interweaving strategy can be applied to stochastic volatility models in order to greatly improve sampling efficiency for all parameters and throughout the entire parameter range. Moreover, this method of "combining best of different worlds" allows for inference for parameter constellations that have previously been infeasible to estimate without the need to select a particular parameterization beforehand.Series: Research Report Series / Department of Statistics and Mathematic

Integrating static and dynamic information for routing traffic

The efficiency of traffic routing on complex networks can be reflected by two key measurements i.e. the system capacity and the average data packets travel time. In this paper, we propose a mixing routing strategy by integrating local static and dynamic information for enhancing the efficiency of traffic on scale-free networks. The strategy is governed by a single parameter. Simulation results show that there exists a optimal parameter value by considering both maximizing the network capacity and reducing the packet travel time. Comparing with the strategy by adopting exclusive local static information, the new strategy shows its advantages in improving the efficiency of the system. The detailed analysis of the mixing strategy is provided. This work suggests that how to effectively utilize the larger degree nodes plays the key role in the scale-free traffic systems.Comment: 5 pages, 5 figure

Competition and Efficiency in Markets with Quality Uncertainty

This paper addresses the following question: Does competition enhance efficiency in markets with quality uncertainty? Using the mechanism design methodology, we characterize the maximal achievable level of efficiency in such markets, and then use this characterization to analyze how maximal efficiency varies with the degree of market competition. We show that the relationship between them is in general a non-trivial function of the main market parameters. In particular we show: (i) for some set of parameter values maximal efficiency is strictly increasing in the degree of market competition (although it never attains the first-best), but only until competition is sufficiently intense; thereafter, maximal efficiency is strictly decreasing in the degree of competition; (ii) for some set of parameter values maximal efficiency is strictly decreasing in the degree of market competition, attaining the first-best when there is no competition; and (iii) for some set of parameter values maximal efficiency is strictly increasing in the degree of market competition, attains the first-best once competition is sufficiently intense, and then remains at the first-best thereafter.