Questioning the relationship between the χ\chi4 susceptibility and the dynamical correlation length in a glass former

Clusters of fast and slow correlated particles, identified as dynamical heterogeneities (DHs), con-stitute a central aspect of glassy dynamics. A key ingredient of the glass transition scenario is asignificant increase of the cluster size $\xi$4 as the transition is approached. In need of easy-to-computetools to measure $\xi$4 , the dynamical susceptibility $\chi$4 was introduced recently, and used in various ex-perimental works to probe DHs. Here, we investigate DHs in dense microgel suspensions using imagecorrelation analysis, and compute both $\chi$4 and the four-point correlation function G4 . The spatialdecrease of G4 provides a direct access to $\xi$4 , which is found to grow significantly with increasingvolume fraction. However, this increase is not captured by $\chi$4 . We show that the assumptions thatvalidate the connection between $\chi$4 and $\xi$4 are not fulfilled in our experiments.Comment: The present version was accepted for publication in Soft Matter (http://pubs.rsc.org/en/journals/journalissues/sm

Spatially heterogeneous dynamics in a thermosensitive soft suspension before and after the glass transition

The microscopic dynamics and aging of a soft thermosensitive suspension was investigated by looking at the thermal fluctuations of tracers in the suspension. Below and above the glass transition, the dense microgel particles suspension was found to develop an heterogeneous dynamics, featured by a non Gaussian Probability Distribution Function (PDF) of the probes' displacements, with an exponential tail. We show that non Gaussian shapes are a characteristic of the ensemble-averaged PDF, while local PDF remain Gaussian. This shows that the scenario behind the non Gaussian van Hove functions is a spatially heterogeneous dynamics, characterized by a spatial distribution of locally homogeneous dynamical environments through the sample, on the considered time scales. We characterize these statistical distributions of dynamical environments, in the liquid, supercooled, and glass states, and show that it can explain the observed exponential tail of the van Hove functions observed in the concentrated states. The intensity of spatial heterogeneities was found to amplify with increasing volume fraction. In the aging regime, it tends to increase as the glass gets more arrested.Comment: 19 pages, 10 figures, Soft Matter accepte

A Fuzzy-Logic Approach to Dynamic Bayesian Severity Level Classification of Driver Distraction Using Image Recognition

open access articleDetecting and classifying driver distractions is crucial in the prevention of road accidents. These distractions impact both driver behavior and vehicle dynamics. Knowing the degree of driver distraction can aid in accident prevention techniques, including transitioning of control to a level 4 semi- autonomous vehicle, when a high distraction severity level is reached. Thus, enhancement of Advanced Driving Assistance Systems (ADAS) is a critical component in the safety of vehicle drivers and other road users. In this paper, a new methodology is introduced, using an expert knowledge rule system to predict the severity of distraction in a contiguous set of video frames using the Naturalistic Driving American University of Cairo (AUC) Distraction Dataset. A multi-class distraction system comprises the face orientation, drivers’ activities, hands and previous driver distraction, a severity classification model is developed as a discrete dynamic Bayesian (DDB). Furthermore, a Mamdani-based fuzzy system was implemented to detect multi- class of distractions into a severity level of safe, careless or dangerous driving. Thus, if a high level of severity is reached the semi-autonomous vehicle will take control. The result further shows that some instances of driver’s distraction may quickly transition from a careless to dangerous driving in a multi-class distraction context

Helical Packings and Phase Transformations of Soft Spheres in Cylinders

The phase behavior of helical packings of thermoresponsive microspheres inside glass capillaries is studied as a function of volume fraction. Stable packings with long-range orientational order appear to evolve abruptly to disordered states as particle volume fraction is reduced, consistent with recent hard sphere simulations. We quantify this transition using correlations and susceptibilities of the orientational order parameter psi_6. The emergence of coexisting metastable packings, as well as coexisting ordered and disordered states, is also observed. These findings support the notion of phase transition-like behavior in quasi-1D systems.Comment: 5 pages, with additional 4 pages of supplemental material, accepted to Physical Review E: Rapid Communication

Management of XML data by means of schema matching

Alsayed Alshahat Alsayed Algergaw

Direct entropy determination and application to artificial spin ice

From thermodynamic origins, the concept of entropy has expanded to a range of statistical measures of uncertainty, which may still be thermodynamically significant. However, laboratory measurements of entropy continue to rely on direct measurements of heat. New technologies that can map out myriads of microscopic degrees of freedom suggest direct determination of configurational entropy by counting in systems where it is thermodynamically inaccessible, such as granular and colloidal materials, proteins and lithographically fabricated nanometre-scale arrays. Here, we demonstrate a conditional-probability technique to calculate entropy densities of translation-invariant states on lattices using limited configuration data on small clusters, and apply it to arrays of interacting nanometre-scale magnetic islands (artificial spin ice). Models for statistically disordered systems can be assessed by applying the method to relative entropy densities. For artificial spin ice, this analysis shows that nearest-neighbour correlations drive longer-range ones.Comment: 10 page

Length-weight relationships and relative condition factor of Parapenaeopsis sculptilis (Heller, 1862) from the coastal waters of Perak, Peninsular Malaysia

Length-weight relationship (LWR) parameters and relative condition factor (K n) of marine shrimp, Parapenaeopsis sculptilis (Heller, 1862) were estimated using length-weight data collected between February 2012 and January 2013 from the coastal waters of Terong, Perak, Peninsular Malaysia. The estimated length-weight relationship of P. sculptilis for both sexes was W = 0.00027TL2.80. Meanwhile, the estimated relative growth coefficient (b) was 2.80 for both sexes, indicating a negative allometric growth pattern of P. sculptilis in the investigated area. Relative condition factor (Kn) values ranged from 0.99 to 1.064 (1.013±0.005, mean ±SD). Kn value changes in various months: the highest peak was in March-April, indicating the spawning period and the trough and small peaks indicating the cycle gonadal development

Flexural performance of FRP reinforced concrete beams

yesA numerical method for estimating the curvature, deflection and moment capacity of FRP reinforced concrete beams is developed. Force equilibrium and strain compatibility equations for a beam section divided into a number of segments are numerically solved due to the non-linear behaviour of concrete. The deflection is then obtained from the flexural rigidity at mid-span section using the deflection formula for various load cases. A proposed modification to the mid-span flexural rigidity is also introduced to account for the experimentally observed wide cracks over the intermediate support of continuous FRP reinforced concrete beams. Comparisons with experimental results show that the proposed numerical technique can accurately predict moment capacity, curvature and deflection of FRP reinforced concrete beams. The ACI-440.1R-06 equations reasonably predicted the moment capacity of FRP reinforced concrete beams but progressively underestimated the deflection of continuous ones. On the other hand, the proposed modified formula including a correction factor for the beam flexural rigidity reasonably predicted deflections of continuous FRP reinforced concrete beams. It was also shown that a large increase in FRP reinforcement slightly increases the moment capacity of FRP over-reinforced concrete beams but greatly reduces the defection after first cracking

Population dynamics of sergestid shrimps Acetes japonicus in the estuary of Tanjung Dawai, Kedah, Malaysia

Population parameters of male and female A. japonicus were studied using the monthly length frequency data to evaluate the mortality rates and its exploitation level. The sex ratio (male: Female) was found at 1: 0.94. Asymptotic length (L∞) was 25.20 mm and 28.88 mm for male and female, respectively. Growth co-efficient (K) for males and females was estimated at 1.80 and 1.30 year-1, respectively. Total mortality (Z) was calculated at 5.98 and 4.44 year-1 for male and female of A. japonicus respectively. Natural mortality (M) was 2.82 and 2.19 year-1 for the male and female shrimps. The fishing mortality (F) was 3.16 year-1 for male and 2.25 year-1 for female. Exploitation level (E) for male and female of A. japonicus was calculated at 0.53 and 0.51. The exploitation level was slightly over (E>0.50) the optimum level of exploitation (p = 0.50). The stock of A. japonicus was found to be slightly over exploited in Tanjung Dawai estuarine waters

Essays in statistical arbitrage

This three-paper thesis explores the important relationship between arbitrage and price efficiency. Chapter 3 investigates the risk-bearing capacity of arbitrageurs under varying degrees and types of risk. A novel stochastic process is introduced to the literature that is capable of jointly capturing fundamental risk factors which are absent from extant specifications. Using stochastic optimal control theory, the degree to which arbitrageurs' investment behaviour is affected by aversion to these risks is analytically characterized, as well as conditions under which arbitrageurs cut losses, effectively exacerbating pricing disequilibria. Chapter 4 explores the role of arbitrage in enforcing price parity between cross-listed securities. This work employs an overlooked mechanism by which arbitrage can maintain parity, namely pairs-trading, which is cheaper to implement than the mechanism most commonly employed in the literature on cross-listed securities. This work shows that arbitrage is successful at enforcing parity between cross-listed securities, and also documents the main limits to arbitrage in this market setting. Chapter 5 examines the extent to which arbitrage contributes to the flow of information across markets. It is shown that microscopic lead/lag relationships of the order of a few hundred milliseconds exist across three major international index futures. Importantly, these delays last long enough, and induce pricing anomalies large enough, to compensate arbitrageurs for appropriating pricing disequilibria. These results accord with the view that temporary disequilibria incentivise arbitrageurs to correct pricing anomalies