Transparent authentication: Utilising heart rate for user authentication

There has been exponential growth in the use of wearable technologies in the last decade with smart watches having a large share of the market. Smart watches were primarily used for health and fitness purposes but recent years have seen a rise in their deployment in other areas. Recent smart watches are fitted with sensors with enhanced functionality and capabilities. For example, some function as standalone device with the ability to create activity logs and transmit data to a secondary device. The capability has contributed to their increased usage in recent years with researchers focusing on their potential. This paper explores the ability to extract physiological data from smart watch technology to achieve user authentication. The approach is suitable not only because of the capacity for data capture but also easy connectivity with other devices - principally the Smartphone. For the purpose of this study, heart rate data is captured and extracted from 30 subjects continually over an hour. While security is the ultimate goal, usability should also be key consideration. Most bioelectrical signals like heart rate are non-stationary time-dependent signals therefore Discrete Wavelet Transform (DWT) is employed. DWT decomposes the bioelectrical signal into n level sub-bands of detail coefficients and approximation coefficients. Biorthogonal Wavelet (bior 4.4) is applied to extract features from the four levels of detail coefficents. Ten statistical features are extracted from each level of the coffecient sub-band. Classification of each sub-band levels are done using a Feedforward neural Network (FF-NN). The 1 st , 2 nd , 3 rd and 4 th levels had an Equal Error Rate (EER) of 17.20%, 18.17%, 20.93% and 21.83% respectively. To improve the EER, fusion of the four level sub-band is applied at the feature level. The proposed fusion showed an improved result over the initial result with an EER of 11.25% As a one-off authentication decision, an 11% EER is not ideal, its use on a continuous basis makes this more than feasible in practice

Vacuum Decay and Euclidean Lattice Monte Carlo

The decay rate of a metastable vacuum is usually calculated using a semiclassical approximation to the Euclidean path integral. The extension to a complete Euclidean lattice Monte Carlo computation, however, is hampered by analytic continuations that are ill-suited to numerical treatment, and the nonequilibrium nature of a metastable state. In this paper we develop a new methodology to compute vacuum decay rates from Monte Carlo simulations of Euclidean lattice theories. To test the new method, we consider simple quantum mechanical systems systems with metastable vacua. This work can be extended to Euclidean field theories, which we discuss in the Conclusions.Comment: 33 pages, 10 figure

Entanglement for a Bimodal Cavity Field Interacting with a Two-Level Atom

Negativity has been adopted to investigate the entanglement in a system composed of a two-level atom and a two-mode cavity field. Effects of Kerr-like medium and the number of photon inside the cavity on the entanglement are studied. Our results show that atomic initial state must be superposed, so that the two cavity field modes can be entangled. Moreover, we also conclude that the number of photon in the two cavity mode should be equal. The interaction between modes, namely, the Kerr effect, has a significant negative contribution. Note that the atom frequency and the cavity frequency have an indistinguishable effect, so a corresponding approximation has been made in this article. These results may be useful for quantum information in optics systems.Comment: Accepted by Commun. Theor. Phy

Helium bubble formation in ultrafine and nanocrystalline tungsten under different extreme conditions

We have investigated the effects of helium ion irradiation energy and sample temperature on the performance of grain boundaries as helium sinks in ultrafine grained and nanocrystalline tungsten. Irradiations were performed at displacement and non-displacement energies and at temperatures above and below that required for vacancy migration. Microstructural investigations were performed using Transmission Electron Microscopy (TEM) combined with either in-situ or ex-situ ion irradiation. Under helium irradiation at an energy which does not cause atomic displacements in tungsten (70 eV), regardless of temperature and thus vacancy migration conditions, bubbles were uniformly distributed with no preferential bubble formation on grain boundaries. At energies that can cause displacements, bubbles were observed to be preferentially formed on the grain boundaries only at high temperatures where vacancy migration occurs. Under these conditions, the decoration of grain boundaries with large facetted bubbles occurred on nanocrystalline grains with dimensions less than 60 nm. We discuss the importance of vacancy supply and the formation and migration of radiation-induced defects on the performance of grain boundaries as helium sinks and the resulting irradiation tolerance of ultrafine grained and nanocrystalline tungsten to bubble formatio

Dissymmetrical U-Shaped π-Stacked Supramolecular Assemblies by Using a Dinuclear CuI Clip with Organophosphorus Ligands and Monotopic Fully π-Conjugated Ligands

International audienceReactions between the U-shape binuclear CuI complex A bearing short metal-metal distances and the cyano-capped monotopic π-conjugated ligands 1-5 carrying gradually bulkier polyaromatic terminal fragments lead to the formation of π-stacked supramolecular assemblies 6-10 respectively in 50-80 % yields. These derivatives have been characterized by multinuclear NMR spectroscopy and X-ray diffraction studies. Their solid state structures show the selective formation of U-shaped supramolecular assemblies in which two monotopic π-conjugated systems present large (6,7,9) or medium (8,10) intramolecular π-overlap revealing π-π interactions. These assemblies self-organize into head-to-tail π-stacked dimers that in turn self-assemble affording infinite columnar π-stacks. The nature, the extentand the complexity of the intermolecular contacts within the head-to-tail π-stacked dimer depends on the nature of the terminal polyaromatic fragment carried by the cyano-capped monotopic ligand but it does not alter the result of the self-assembling process. These results demonstrate that the dinuclear molecular clip A bearing short metal-metal distance allows selective supramolecular assembling processes driven by the formation of intra- and intermolecular short π-π interactions in the resulting self-assembled structures demonstrating that their shape is not only dictated by the symmetry of the building blocks. This approach opens perspectives toward the formation of extented π-stacked columns based on dissymmetrical and functionnal π-conjugated systems

Isolation of networking process in a browser

Computer programs and applications are often designed such that sub-tasks of a program are executed by a separate process spawned by the main program or application. An advantage to such a design is resilience, e.g., even if one process fails, the remaining processes continue execution, even as the failed process is started anew. In the context of web browser applications, networking requests are typically not spawned as separate processes but rather handled by the main browser process itself. This can lead to problems of stability, security, and resilience. The techniques of this disclosure spawn the networking tasks of a web browser into a separate process, and can provide improved stability, security, and resilience

Modelling complex cracks with finite elements: a kinematically enriched constitutive model

A continuum constitutive framework with embedded cohesive interface model is presented to describe the failure of quasi-brittle materials. Both cohesive behaviour for cracking inside the fracture process zone and elastic bulk behaviour are treated at integration points making implementation straightforward. In this sense, the proposed approach is simpler than existing ones that focus on element enrichments, such as the extended finite element method, while share similarities with smeared crack models, and offers the capability to correctly model quasi-brittle failure in post-peak regime at constitutive level. In this work, the formulation is introduced, numerical algorithms described and static and dynamic fracture simulations with complex crack patterns are conducted to demonstrate the capability and advantage of the proposed approach.ARC DP140100945, ARC FT140100408, ARC DE 15010170