Adaptive Spatial Partitioning for Multidimensional Data Streams

We propose a space-efficient scheme for summarizing multidimensional data streams. Our sketch can be used to solve spatial versions of several classical data stream queries efficiently. For instance, we can track ε-hot spots, which are congruent boxes containing at least an ε fraction of the stream, and maintain hierarchical heavy hitters in d dimensions. Our sketch can also be viewed as a multidimensional generalization of the ε-approximate quantile summary. The space complexity of our scheme is O((1/ε) log R) if the points lie in the domain [0, R]^d, where d is assumed to be a constant. The scheme extends to the sliding window model with a log (ε n) factor increase in space, where n is the size of the sliding window. Our sketch can also be used to answer ε-approximate rectangular range queries over a stream of d-dimensional points.     

A confocal microscopic evaluation of the effects of insulin imprinting on the binding of Concanavalin A by Tetrahymena Pyriformis

With confocal microscopy it is possible to study the Concanavalin A (Con A) binding characteristics of the surface and interior of a single cell by viewing optical sections. It was observed in Tetrahymena pyriformis that Con A bound both to the plasma membrane and to intracellular structures. Incubation of cells with a competing sugar a-methylmannopyranoside, decreased binding. Hormonal imprinting with insulin resulted in an increase in binding of Con A to the cell surface and a decrease in intracellular binding. It is possible that the intracellular binding sites may migrate to the plasma membrane.     

Solid state reactions in the Fe2O3-CaCO3-In2O3 system

The kinetics of solid-state reactions of powdered reactants were investigated by X-ray and by differential thermogravimetry in a magnetic field. Measurements revealed mutual diffusion of the Fe³⁺ and In³⁺ ions in the Fe₂O₃-In₂O₃ system heat treated for 3 h at 700 to 1400° C. Diffusion of indium into the Fe₂O₃ lattice caused a shift of the Curie temperature of the antiferromagnetic iron oxide towards lower temperatures. Only Caln₂O₄ was found between CaCO₃ and In₂O₃ up to 1400° C. Also, in the Fe₂O₃-CaCO₃-In₂O₃in system, the reaction started with the mutual diffusion of iron and indium and the forming of CaFe₂O₄. End-products were the magnetic -Ca₄Fe₁₄O₂₅ and CaFe₄O₇, and the non-magnetic CaFe₅O₇, depending on the In³⁺ concentration. Indium stabilized the magnetic calcium-iron oxide structures, shifting their Curie temperatures towards lower values.     

Exploiting hardware capabilities in interior point methods

The increase of computer performance continues to support the practice of large-scale optimization. Computers with multiple computing cores and vector processing capabilities are now widely available. We investigate how the recently introduced Advanced Vector Instruction (AVX) set on Intel-compatible architectures can be exploited in interior point methods for linear and nonlinear optimization. We focus on data structures and implementation techniques that utilize the new vector instructions. Our numerical experiments demonstrate that the AVX instruction set provides a significant performance boost in our implementation on large-scale problem that have significant fill-in in the sparse Cholesky factorization, achieving up to 100 gigaflops performance on a standard desktop computer on linear optimization problems for which the required Cholesky factorization is relatively dense.     

Measurement and analysis of low-acceleration and long-duration longitudinal events using delivery van

This study investigates longitudinal acceleration events during freight transportation characterized as low-acceleration and long-duration using delivery van type vehicles. In the past several decades, there has been an increase in shipments requiring only single or small pallet load quantities and mixed palletized unit loads comprised of different goods. These loads are often transported in delivery vans without load securing devices, increasing the risk of product loss and damage due to load failures resulting from unit loads shifting. A field data acquisition system was used to observe and record the random acceleration events from five vehicles for 5 days, explicitly targeting the vehicles' braking and acceleration manoeuvres. The study aimed to understand the physical phenomenon and provide new information that can be used during preshipment tests to prevent damage to goods and ensure unit load integrity is maintained throughout the supply chain. The events were statistically analysed to understand their probability of occurrence, severity level, and quantify critical parameters such as event rise and hold times. For the braking manoeuvre, the statistical mean of average deceleration was 0.25 g with a corresponding rise and hold duration of 0.83 and 1.27 s, respectively. During the vehicle's acceleration manoeuvre, the statistical mean of average acceleration was 0.29 g with a rise and hold time of 1.29 and 1.39 s, respectively. Utilizing the field data, composite profiles were developed, and these profiles were compared to the currently available test procedures and previous results of other studies.     

Parametric estimation of affine deformations of planar shapes

We consider the estimation of affine transformations aligning a known 2D shape and its distorted observation. The classical way to solve this registration problem is to find correspondences between the shapes and then compute the transformation parameters from these landmarks. Here we propose a novel approach where the exact transformation is obtained as the solution of a polynomial system of equations. The method has been tested on synthetic as well as on real images and its robustness in the presence of segmentation errors and additive geometric noise has also been demonstrated. We have successfully applied the method for the registration of hip prosthesis X-ray images. The advantage of the proposed solution is that it is fast, easy to implement, has linear time complexity, works without established correspondences and provides an exact solution regardless of the magnitude of transformation.     

Multiplicity results for some elliptic problems with nonlinear boundary conditions involving variable exponents

In this paper we analyze an elliptic partial differential equation involving variable exponent growth conditions coupled with a nonlinear boundary condition. We show the existence of infinitely many bounded weak solutions provided there is a suitable oscillatory behavior of the nonlinearity either at infinity or at zero. Our proofs rely on a method due to Saint Raymond.