Role of vanadium oxide on the lithium silicate glass structure and properties

The structural role of V in 28Li₂O–72SiO₂ (in mol%) lithium silicate glass doped with 0.5 mol% V₂O₅ was assessed using ²⁹Si and ⁵¹V Nuclear Magnetic Resonance (NMR), Fourier-transform infrared (FTIR), and X-ray photoelectron (XPS) spectroscopy techniques. Despite the low amount of V₂O₅ used, the structural information obtained or deduced from the statistical analysis of the NMR data could explain the evolution of glass properties after V₂O₅ addition. The XPS results indicated that all vanadium exists in 5+ oxidation state. Both the ²⁹Si NMR and FTIR data point toward an increase in the polymerization of the silicate network, caused by the V₂O₅ acting as network former, capable to form various tetrahedral units (for n = 0, 1, and 2) in the glasses. These units, which are similar to phosphate units, scavenge the Li⁺ ions and cause the silicate network to polymerize. However, in an overall balance, the entire glass network is depolymerized due to the additional nonbridging oxygens contributed by the vanadium polyhedra. The addition of vanadium causes the network to expand and increases the ionic conductivity.     

Typing artifacts in megamodeling

Model management is essential for coping with the complexity introduced by the increasing number and varied nature of artifacts involved in model-driven engineering-based projects. Global model management (GMM) addresses this issue by enabling the representation of artifacts, particularly transformation composition and execution, within a model called a megamodel. Type information about artifacts can be used for preventing type errors during execution. Built on our previous work, in this paper we present the core elements of a type system for GMM that improves its original typing approach and enables both typechecking and type inference on artifacts within a megamodel. This type system is able to deal with non-trivial situations such as the use of higher order transformations. We also present a prototypical implementation of such a type system.     

DETONATION CLASSIFICATION FROM ACOUSTIC SIGNATURE WITH THE RESTRICTED BOLTZMANN MACHINE

We compare the recently proposed Discriminative Restricted Boltzmann Machine (DRBM) to the classical Support Vector Machine (SVM) on a challenging classification task consisting in identifying weapon classes from audio signals. The three weapon classes considered in this work (mortar, rocket, and rocket‐propelled grenade), are difficult to reliably classify with standard techniques because they tend to have similar acoustic signatures. In addition, specificities of the data available in this study make it challenging to rigorously compare classifiers, and we address methodological issues arising from this situation. Experiments show good classification accuracy that could make these techniques suitable for fielding on autonomous devices. DRBMs appear to yield better accuracy than SVMs, and are less sensitive to the choice of signal preprocessing and model hyperparameters. This last property is especially appealing in such a task where the lack of data makes model validation difficult.     

Validation of SeaWiFS-derived chlorophyll for the Rio de la Plata Estuary and adjacent waters

The South Atlantic Ocean near the Río de la Plata Estuary is a highly dynamic region that encompasses four different water bodies: the Río de la Plata, the continental shelf and the Brazil and Malvinas currents. Bio-optical measurements obtained during 6–11 November 1999 provided the initial field data for validating Sea viewing Wide Field of view Sensor (SeaWiFS)-derived chlorophyll imagery for this region. The turbid waters of the Río de la Plata Estuary showed the highest variability and complexity in water optical properties, while the offshore waters of the Brazil Current had the lowest. In most cases, the estimates of chlorophyll using the SeaWiFS algorithm were higher than in situ measured values.     

Efficient disparity vector prediction schemes with modified P frame for 2D camera arrays

An efficient disparity estimation algorithm for multi-view video sequences, recorded by a two-dimensional camera array in which the cameras are spaced equidistantly, is presented. Because of the strong geometrical relationship among views, the disparity vectors of a certain view can for most blocks be derived from the disparity vectors of other views. A frame constructed using that idea is called a D frame in this work. Three new prediction schemes which contain D frames are proposed for encoding 5 × 3 multi-view video sequences. The schemes are applied to several multi-view image sequences taken from a camera-array and they are compared in terms of quality, bit-rate and complexity. The experimental results show that the proposed prediction schemes significantly decrease the complexity of the encoder at a very low cost of quality and/or bit-rate.     

Mobile touchscreen user interfaces: bridging the gap between motor-impaired and able-bodied users

Touchscreen mobile devices are highly customizable, allowing designers to create inclusive user interfaces that are accessible to a broader audience. However, the knowledge to provide this new generation of user interfaces is yet to be uncovered. The goal was to thoroughly study mobile touchscreen interfaces and provide guidelines for informed design. The paper presents an evaluation performed with 15 tetraplegic and 18 able-bodied users that allowed to identify their main similarities and differences within a set of interaction techniques (Tapping, Crossing, and Directional Gesturing) and parameterizations. Results show that Tapping and Crossing are the most similar and easy to use techniques for both motor-impaired and able-bodied users. Regarding Tapping, error rates start to converge at 12 mm, showing to be a good compromise for target size. As for Crossing, it offered a similar level of accuracy; however, larger targets (17 mm) are significantly easier to cross for motor-impaired users. Directional Gesturing was the least inclusive technique. Regarding position, edges showed to be troublesome. For instance, they have shown to increase Tapping precision for disabled users, while decreasing able-bodied users’ accuracy when targets are too small (7 mm). It is argued that despite the expected error rate disparity, there are clear resemblances between user groups, thus enabling the development of inclusive touch interfaces. Tapping, a traditional interaction technique, was among the most effective for both target populations, along with Crossing. The main difference concerns Directional Gesturing that in spite of its unconstrained nature shows to be inaccurate for motor-impaired users.     

Alterations in gap junction connexin43/connexin45 ratio mediate a transition from quiescence to excitation in a mathematical model of the myometrium

The smooth muscle cells of the uterus contract in unison during delivery. These cells achieve coordinated activity via electrical connections called gap junctions which consist of aggregated connexin proteins such as connexin43 and connexin45. The density of gap junctions governs the excitability of the myometrium (among other factors). An increase in gap junction density occurs immediately prior to parturition. We extend a mathematical model of the myometrium by incorporating the voltage-dependence of gap junctions that has been demonstrated in the experimental literature. Two functional subtypes exist, corresponding to systems with predominantly connexin43 and predominantly connexin45, respectively. Our simulation results indicate that the gap junction protein connexin45 acts as a negative modulator of uterine excitability, and hence, activity. A network with a higher proportion of connexin45 relative to connexin43 is unable to excite every cell. Connexin45 has much more rapid gating kinetics than connexin43 which we show limits the maximum duration of a local burst of activity. We propose that this effect regulates the degree of synchronous excitation attained during a contraction. Our results support the hypothesis that as labour approaches, connexin45 is downregulated to allow action potentials to spread more readily through the myometrium.     

Check Your Biosignals Here: A new dataset for off-the-person ECG biometrics

The Check Your Biosignals Here initiative (CYBHi) was developed as a way of creating a dataset and consistently repeatable acquisition framework, to further extend research in electrocardiographic (ECG) biometrics. In particular, our work targets the novel trend towards off-the-person data acquisition, which opens a broad new set of challenges and opportunities both for research and industry. While datasets with ECG signals collected using medical grade equipment at the chest can be easily found, for off-the-person ECG data the solution is generally for each team to collect their own corpus at considerable expense of resources. In this paper we describe the context, experimental considerations, methods, and preliminary findings of two public datasets created by our team, one for short-term and another for long-term assessment, with ECG data collected at the hand palms and fingers.     

A review of the statistical turbulence theory required extending the population balance closure models to the entire spectrum of turbulence

The models for fluid particle breakage and coalescence due to turbulence are generally limited to the inertial subrange of isotropic turbulence and infinite Reynolds numbers. A rigorous procedure for extending the fluid particle breakage and coalescence closures to the entire spectrum of isotropic turbulence and for a wider range of Reynolds numbers can be established based on statistical turbulence theory. The modeling procedure consists of a three‐dimensional (3‐D) literature model energy spectrum for the dissipation, inertial, and energy containing subranges of isotropic turbulence, and an exact literature integral relation for determining the second‐order longitudinal structure function from the 3‐D energy spectrum. A review of the requisite statistical turbulence theory and the use of the model energy spectrum is provided, because the necessary details are not easily accessible in the chemical engineering literature and misconceptions are found in the publications of the previous modeling attempts. © 2016 American Institute of Chemical Engineers AIChE J, 62: 1795–1820, 2016