Developing Systems for Real-Time Streaming Analysis

Sources of streaming data are proliferating and so are the demands to analyze and mine such data in real time. Statistical methods frequently form the core of real-time analysis, and therefore, statisticians increasingly encounter the challenges and implicit requirements of real-time systems. This work recommends a comprehensive strategy for development and implementation of streaming algorithms, beginning with exploratory data analysis in a flexible computing environment, leading to specification of a computational algorithm for the streaming setting and its initial implementation, and culminating in successive improvements to computational efficiency and throughput. This sequential development relies on a collaboration between statisticians, domain scientists, and the computer engineers developing the real-time system. This article illustrates the process in the context of a radio astronomy challenge to mitigate adverse impacts of radio frequency interference (noise) in searches for high-energy impulses from distant sources. The radio astronomy application motivates discussion of system design, code optimization, and the use of hardware accelerators such as graphics processing units, field-programmable gate arrays, and IBM Cell processors. Supplementary materials, available online, detail the computing systems typically used for streaming systems with real-time constraints and the process of optimizing code for high efficiency and throughput.     

Epitaxial film crystallography by high-energy Auger and X-ray photoelectron diffraction

We review recent work in the application of Auger and X-ray photoelectron diffraction at high electron kinetic energies to the problem of structure determination in ultrathin epitaxial overlayers. These closely-related techniques are based on the fact that outgoing Auger and photoelectrons from single-crystal specimens undergo elastic scattering and interference from near-neighbour atoms in the vicinity of the emitter. Such coherent diffraction leads to large intensity modulations as the detected emission direction is varied with respect to the crystal axes of the specimen. The measured modulations are readily interpreted by means of model quantum mechanical scattering calculation in which atomic coordinates in the epitaxial film are systematically varied. Such analyses provide several kinds of useful information, including growth modes accompanying heteroepitaxy, structural details of alloy and compound formation, and quantitative determination of tetragonal distortion at lattice-mismatched heterointerfaces. After a discussion of experimental design and theoretical modelling, we present several case studies of heteroepitaxial growth involving dissimilar materials. In addition, we review the new subfield of Auger and photoelectron holography, and discuss the current state-of-art in both data acquisition and Fourier inversion of experimental data for directly obtaining structural parameters.     

Near-Optimal Mean Value Estimates for Multidimensional Weyl Sums

We obtain sharp estimates for multidimensional generalisations of Vinogradov’s mean value theorem for arbitrary translation-dilation invariant systems, achieving constraints on the number of variables approaching those conjectured to be the best possible. Several applications of our bounds are discussed.     

Bezout and prufer f-rings

This article describes Bezout and Prüfer f-rings in terms of their localizations. All f-rings here are corrmutative, semi prime and possess an identity; they also have the bounded inversion property: a >1 implies that a is a multiplicative unit. The two main theorems are as follows: (1) A is a Bezout f-ring if and only if each localization at a maximal ideal is a (totally ordered) valuation ring; (2) Each Prufer f-ring is quasi-Bezout, and if each localization of A is a Prufer f-ring then so is A. We give a counter-example to show that the converse of the last assertion is false.     

A rapid method for analysis of non-equilibrated 90Sr/90Y in infant formula

Journal of Radioanalytical and Nuclear Chemistry - A rapid analytical method for quantifying 90Sr in infant formula prior to secular equilibrium is presented. The approach is dependent on the use...     

Dynamic Ion Speciation during the Hydrolysis of Aryltrifluoroborates**

Organotrifluoroborates serve as coupling partners during transmetalation in the Suzuki–Miyaura reaction but require hydrolysis prior to the coupling reaction. Their anionic nature allows study of their hydrolysis by electrospray ionization mass spectrometry (ESI-MS) through real-time monitoring, complemented by pH analysis. The induction period varied according to the borates employed, and a dynamic series of equilibria for numerous ions was observed during hydrolysis. We found that the induction periods and reaction rates were sensitive to the R group of the borates, the shape of the reaction vessel, and stir rate.