t1/3t^{1/3} Superdiffusivity of Finite-Range Asymmetric Exclusion Processes on Z\mathbb Z

We consider finite-range asymmetric exclusion processes on $\mathbb Z$ with non-zero drift. The diffusivity $D(t)$ is expected to be of ${\mathcal O}(t^{1/3})$. We prove that $D(t)\ge Ct^{1/3}$ in the weak (Tauberian) sense that $\int_0^\infty e^{-\lambda t}tD(t)dt \ge C\lambda^{-7/3}$ as $\lambda\to 0$. The proof employs the resolvent method to make a direct comparison with the totally asymmetric simple exclusion process, for which the result is a consequence of the scaling limit for the two-point function recently obtained by Ferrari and Spohn. In the nearest neighbor case, we show further that $tD(t)$ is monotone, and hence we can conclude that $D(t)\ge Ct^{1/3}(\log t)^{-7/3}$ in the usual sense.Comment: Version 3. Statement of Theorem 3 is correcte

Equilibrium fluctuations for the totally asymmetric zero-range process

We consider the one-dimensional Totally Asymmetric Zero-Range process evolving on $\mathbb{Z}$ and starting from the Geometric product measure $\mu_\rho$. On the hyperbolic time scale the temporal evolution of the density fluctuation field is deterministic, in the sense that the limit field at time $t$ is a translation of the initial one. We consider the system in a reference frame moving at this velocity and we show that the limit density fluctuation field does not evolve in time until $N^{4/3}$, which implies the current across a characteristic to vanish on this longer time scale.The author wants to express her gratitude to "Fundacao para a Ciencia e Tecnologia" for the grant /SFRH/BPD/39991/2007, to CMAT from University of Minho for support and to "Fundacao Calouste Gulbenkian" for the Prize: "Estimulo a investigacao" of the research project "Hydrodynamic limit of particle systems"

From Physical to Cyber: Escalating Protection for Personalized Auto Insurance

Nowadays, auto insurance companies set personalized insurance rate based on data gathered directly from their customers' cars. In this paper, we show such a personalized insurance mechanism -- wildly adopted by many auto insurance companies -- is vulnerable to exploit. In particular, we demonstrate that an adversary can leverage off-the-shelf hardware to manipulate the data to the device that collects drivers' habits for insurance rate customization and obtain a fraudulent insurance discount. In response to this type of attack, we also propose a defense mechanism that escalates the protection for insurers' data collection. The main idea of this mechanism is to augment the insurer's data collection device with the ability to gather unforgeable data acquired from the physical world, and then leverage these data to identify manipulated data points. Our defense mechanism leveraged a statistical model built on unmanipulated data and is robust to manipulation methods that are not foreseen previously. We have implemented this defense mechanism as a proof-of-concept prototype and tested its effectiveness in the real world. Our evaluation shows that our defense mechanism exhibits a false positive rate of 0.032 and a false negative rate of 0.013.Comment: Appeared in Sensys 201

Equilibrium fluctuations of additive functionals of zero-range models

For mean-zero and asymmetric zero-range processes on $\Z^d$, the fluctuations of additive functionals starting from an invariant measure are considered. Under certain assumptions, we establish when the fluctuations are diffusive and satisfy functional central limit theorems. These results complement those for symmetric zero-range systems and also those for simple exclusion models already in the literature.FC

Superdiffusivity of Asymmetric Energy Model in Dimension One and Two

We discuss an asymmetric energy model (AEM) introduced by Giardina et al. in \cite{7}. This model is expected to belong to the KPZ class. We obtain lower bounds for the diffusion coefficient. In particular, the diffusion coefficient is diverging in dimension one and two as it is expected in the KPZ picture

Occupation times of long-range exclusion and connections to KPZ class exponents

With respect to a class of long-range exclusion processes on \ZZ^d, with single particle transition rates of order $|\cdot|^{-(d+\alpha)}$, starting under Bernoulli invariant measure $\nu_\rho$ with density $\rho$, we consider the fluctuation behavior of occupation times at a vertex and more general additive functionals. Part of our motivation is to investigate the dependence on $\alpha$, $d$ and $\rho$ with respect to the variance of these functionals and associated scaling limits. In the case the rates are symmetric, among other results, we find the scaling limits exhaust a range of fractional Brownian motions with Hurst parameter $H\in [1/2,3/4]$. However, in the asymmetric case, we study the asymptotics of the variances, which when $d=1$ and $\rho=1/2$ points to a curious dichotomy between long-range strength parameters $03/2$. In the former case, the order of the occupation time variance is the same as under the process with symmetrized transition rates, which are calculated exactly. In the latter situation, we provide consistent lower and upper bounds and other motivations that this variance order is the same as under the asymmetric short-range model, which is connected to KPZ class scalings of the space-time bulk mass density fluctuations.The research of CB was supported in part by the French Ministry of Education through the grant ANR JCJC EDNHS. PG thanks FCT (Portugal) for support through the research project PTDC/MAT/109844/2009 and CNPq (Brazil) for support through the research project 480431/2013-2. PG thanks CMAT for support by "FEDER" through the "Programa Operacional Factores de Competitividade COMPETE" and by FCT through the project PEst-C/MAT/UI0013/2011. SS was supported in part by ARO grant W911NF-14-1-0179

Estimation of state of charge of lead-acid battery used in solar photovoltaic system

7-19An accurate estimation of State of charge (SOC) of the lead-acid battery is of paramount importance for the efficient and reliable operation of solar photovoltaic (SPV) sytem. There are mainly four methods used for estimating SOC of the battery, viz. chemical, voltage, current integration and kalman filtering. In this present study, the SOC as indicated by the solar power conditioning unit (SPCU) was taken as reference and at every 5% SOC reduction, the other parameters such as- i) specific gravity of electrolyte, ii) battery terminal voltage, iii) (Ampere Hour) Ah and iv) energy deliverd to the resistive load were recorded. Based on this recorded values the SOC was predicted. The standard deviation (S.D.) of the difference of predicted SOC to the reference SOC was calculated based on specific gravity, Voltage, Ah and energy. The SD obtained was 6.17, 5.67, 0.33, 0.75 respectively. The specific gravity value for the battery electrolyte decreases with the decrease in the battery SOC%, the maximum value of SG at 100% SOC was 1.23 and the minimum at 20% SOC was 1.14. The terminal voltage was also got reduced with the reduction in SOC, from 24.85V at 100% SOC to 22.4V at 20% SOC. The energy stored by the battery during charging was 3.65 units and the energy delivered from the battery to the load was 3.245 units.  The efficiency of solar panel, lead-acid battery and the combined SPV system was 12.79%, 88.9% and 9.68% respectively. It was found that the SOC of the lead-acid battery would be more accurate when it is estimated based on current integration i.e., Ah, the SOC estimation based on energy is also acceptable since the SD for both is less than 1. Hence, through this investigation we can say that SOC prediction based on Ah or kWh measurement is more appropriate than specific gravity and voltage methods