Scale-effects on mean and standard deviation of the mechanical properties of condensed matter: an energy-based unified approach

The size effects on the mean values of the mechanical properties of condensed matter and on the related variances are analysed by means of a unified approach based on the multiscale character of energy dissipation. In particular, the scaling law for fragmentation energy density is obtained taking into account the self-similarity of fragments. It is based on a generalization of the three classical comminution laws that has been performed to evaluate the energy dissipation, computing volume and surface area of the particles for one- two- and three-dimensional fragmented objects. The result is general and can be applied to different fractal energy dissipation mechanisms, e.g., plasticity. Based on this approach, the scaling laws for mean and standard deviation values of the main mechanical properties of materials can be derived, like Young's and shear elastic moduli, ultimate normal and shear stresses and strains, fracture energy and toughness.     

Genetic programming of conventional features to detect seizure precursors

This paper presents an application of genetic programming (GP) to optimally select and fuse conventional features (C-features) for the detection of epileptic waveforms within intracranial electroencephalogram (IEEG) recordings that precede seizures, known as seizure precursors. Evidence suggests that seizure precursors may localize regions important to seizure generation on the IEEG and epilepsy treatment. However, current methods to detect epileptic precursors lack a sound approach to automatically select and combine C-features that best distinguish epileptic events from background, relying on visual review predominantly. This work suggests GP as an optimal alternative to create a single feature after evaluating the performance of a binary detector that uses: (1) genetically programmed features; (2) features selected via GP; (3) forward sequentially selected features; and (4) visually selected features. Results demonstrate that a detector with a genetically programmed feature outperforms the other three approaches, achieving over 78.5% positive predictive value, 83.5% sensitivity, and 93% specificity at the 95% level of confidence.     

A comparison of MNT curves and supersingular curves

We compare both the security and performance issues related to the choice of MNT curves against supersingular curves in characteristic three, for pairing based systems. We pay particular attention to equating the relevant security levels and comparing not only computational performance and bandwidth performance. The paper focuses on the BLS signature scheme and the Boneh–Franklin encryption scheme, but a similar analysis can be applied to many other pairing based schemes.     

Semi-supervised model adaptation for statistical machine translation

Statistical machine translation systems are usually trained on large amounts of bilingual text (used to learn a translation model), and also large amounts of monolingual text in the target language (used to train a language model). In this article we explore the use of semi-supervised model adaptation methods for the effective use of monolingual data from the source language in order to improve translation quality. We propose several algorithms with this aim, and present the strengths and weaknesses of each one. We present detailed experimental evaluations on the French–English EuroParl data set and on data from the NIST Chinese–English large-data track. We show a significant improvement in translation quality on both tasks.     

A theoretical study of light emission from nanoscale silicon

In comparing our calculated exciton energies with those obtained from pseudopotential calculations (Ref. 27) and from a previous tight binding calculation (Ref. 30), we stated that the differences between the three semi-empirical calculations arise because of different treatment of the nanocrystal surfaces. This appears not to be correct. Subsequent calculations with variable Si-H parameters have shown that the band gap is actually rather insensitive to the actual value of these. Instead, the important feature appears to be the overall quality of the bulk band structure parameterization. References 27 and 30 use more extensive and higher quality empirical parameterizations for bulk Si than the sp³s∗ model used by us. Repeating our time dependent calculations with an improved sp³d⁵ parameterization results in similar values to those of Refs. 27 and 30 for the exciton energies.¹ The agreement of the sp³s∗ values with experimental photoluminescence energies (Fig. 7) cannot, therefore, be regarded as well understood at this time.^1,2