Fast Ridge Regression with Randomized Principal Component Analysis and Gradient Descent

We propose a new two stage algorithm LING for large scale regression problems. LING has the same risk as the well known Ridge Regression under the fixed design setting and can be computed much faster. Our experiments have shown that LING performs well in terms of both prediction accuracy and computational efficiency compared with other large scale regression algorithms like Gradient Descent, Stochastic Gradient Descent and Principal Component Regression on both simulated and real datasets

Universality of collapsing two-dimensional self-avoiding trails

Results of a numerically exact transfer matrix calculation for the model of Interacting Self-Avoiding Trails are presented. The results lead to the conclusion that, at the collapse transition, Self-Avoiding Trails are in the same universality class as the O(n=0) model of Blote and Nienhuis (or vertex-interacting self-avoiding walk), which has thermal exponent $\nu=12/23$, contrary to previous conjectures.Comment: Final version, accepted for publication in Journal of Physics A; 9 pages; 3 figure

Expert perspectives on the future of the organic food market: results of a Pan-European Delphi study

A Delphi Inquiry was carried out to assess the prospect and conditions affecting the overall growth in the European Market for organic products in the coming decade, and to provide support for research. Countries were classified as established, growing and emerging, according to the state of development of their organic market. The survey confirmed the importance of factors influencing the development of the organic food market: the supply base, the role of supermarkets as sales channels and of government support. Organic Producer Initiatives were seen as important in securing a fair deal for organic producers but managerial capacity and professionalism are key challenges for such organizations

The drag of a body moving transversely in a confined stratified fluid

The slow motion of a body through a stratified fluid bounded laterally by insulating walls is studied for both large and small Peclet number. The Taylor column and its associated boundary and shear layers are very different from the analogous problem in a rotating fluid. In particular, the large Peclet number problem is non-linear and exhibits mixing of statically unstable fluid layers, and hence the drag is order one; whereas the small Peclet number flow is everywhere stable, and the drag is of the order of the Peclet number