Generalized Boosting Algorithms for Convex Optimization

Boosting is a popular way to derive powerful learners from simpler hypothesis classes. Following previous work (Mason et al., 1999; Friedman, 2000) on general boosting frameworks, we analyze gradient-based descent algorithms for boosting with respect to any convex objective and introduce a new measure of weak learner performance into this setting which generalizes existing work. We present the weak to strong learning guarantees for the existing gradient boosting work for strongly-smooth, strongly-convex objectives under this new measure of performance, and also demonstrate that this work fails for non-smooth objectives. To address this issue, we present new algorithms which extend this boosting approach to arbitrary convex loss functions and give corresponding weak to strong convergence results. In addition, we demonstrate experimental results that support our analysis and demonstrate the need for the new algorithms we present.Comment: Extended version of paper presented at the International Conference on Machine Learning, 2011. 9 pages + appendix with proof

Coercivity and stability results for an extended Navier-Stokes system

In this article we study a system of equations that is known to {\em extend} Navier-Stokes dynamics in a well-posed manner to velocity fields that are not necessarily divergence-free. Our aim is to contribute to an understanding of the role of divergence and pressure in developing energy estimates capable of controlling the nonlinear terms. We address questions of global existence and stability in bounded domains with no-slip boundary conditions. Even in two space dimensions, global existence is open in general, and remains so, primarily due to the lack of a self-contained $L^2$ energy estimate. However, through use of new $H^1$ coercivity estimates for the linear equations, we establish a number of global existence and stability results, including results for small divergence and a time-discrete scheme. We also prove global existence in 2D for any initial data, provided sufficient divergence damping is included.Comment: 29 pages, no figure

Smeared heat-kernel coefficients on the ball and generalized cone

We consider smeared zeta functions and heat-kernel coefficients on the bounded, generalized cone in arbitrary dimensions. The specific case of a ball is analysed in detail and used to restrict the form of the heat-kernel coefficients $A_n$ on smooth manifolds with boundary. Supplemented by conformal transformation techniques, it is used to provide an effective scheme for the calculation of the $A_n$. As an application, the complete $A_{5/2}$ coefficient is given.Comment: 23 pages, JyTe

Health informatics education for clinicians and managers - What's holding up progress?

This paper reports outcomes of a national survey of health informatics (HI) education and training carried out in the UK. A questionnaire to elicit details of HI and IT skills teaching was derived from a national consensus document (Learning to Manage Health Information, LtMHI). Forms were sent to all pre-qualification medical and nursing schools and to a stratified sample of postgraduate and post-registration programmes. Three case studies were carried out in acute hospital trusts to gain insight into opportunities for continuing professional development in health informatics and IT. Our evidence suggests that in the UK, health informatics is not yet integrated into the clinical curriculum. Nearly all the pre-qualification courses made some provision for teaching IT skills. Nonetheless, many respondents felt that students did not receive sufficient training. There was considerable variation in the amount of HI teaching provided in the different educational sectors. The case studies suggested very little HI training was provided for clinical staff and take-up of provision was not monitored. A number of factors are holding up progress, the most important being a lack of staff with the knowledge and skills to provide academic leadership. The paper outlines some steps that need to be taken to ensure health informatics is embedded in all clinical curricula. © 2003 Elsevier Ireland Ltd. All rights reserved

Realizations of Differential Operators on Conic Manifolds with Boundary

We study the closed extensions (realizations) of differential operators subject to homogeneous boundary conditions on weighted L_p-Sobolev spaces over a manifold with boundary and conical singularities. Under natural ellipticity conditions we determine the domains of the minimal and the maximal extension. We show that both are Fredholm operators and give a formula for the relative index.Comment: 41 pages, 1 figur

Attorneys, Accountants, and Bankers, Oh My! Primary Liability for Secondary Actors in the Wake of Stoneridge

Mervin Buddy Schwartz, Jr., embodied the American Dream. A Pennsylvania resident, Schwartz began working for Hershey Foods in 1961 as a maintenance mechanic.\u27 He eventually became a member of the local union\u27s executive board. A hard worker providing for his family, Schwartz had a thirteen-year perfect attendance record and often worked overtime. He even managed to attend night classes and obtained an associate\u27s degree in Bible studies. Lacking any financial training, Buddy Schwartz relied on the retirement plan and 401k5 Hershey provided for his retirement. Because he contributed the maximum allowable amount out of each paycheck to his 401k, he was able to retire in 1999 at the age of sixty with retirement assets worth approximately $284,000. He rolled these assets over to Merrill Lynch so his son, James Schwartz, a financial advisor, could manage them. Not only did he retire early, but Buddy Schwartz and his wife, Louise, also were able to purchase a retirement home in Arizona to be close to family. For Buddy Schwartz, the American Dream was coming true. This all changed, however, when James called his father in 2000 to tell him about a hot growth stock10 for a fast-growing and stable company called Enron. Relying on positive Merrill Lynch analyst opinions, James advised his father to invest in Enron, which he did by purchasing about$30,000 worth of preferred stock. Imagine Schwartz\u27s despair when the Enron scandal erupted in 2001, and he lost his initial investment and was forced to sell his retirement home in Arizona. Imagine his outrage when he discovered that his brokerage firm, Merrill Lynch, was lying and scheming with Enron to make its financial statements look more promising than they actually were through fraudulent transactions. Imagine his heartbreak when the Fifth Circuit destroyed his American dream in one stroke by failing to certify a nationwide class that would have included Schwartz and other defrauded investors. According to the court, the fraudulent actions did not give rise to primary liability under 10(b) of the Securities Exchange Act of 1934

Differentiation and Dynamics of Competitiveness Impacts from the EU ETS

We summarise the main factors that differentiate impacts of the EU ETS on profitability and market share. By examining and sampling a range of sectors, we present some simple metrics and indicators to help judge the nature of potential impacts. We also consider briefly the mitigation response to these impacts by sectors, and how they may evolve over time. The broad conclusion confirms the aggregate findings presented in the existing literature - more participating sectors are likely to profit under the current ETS structure out to 2012 at the cost of a modest loss of market share, but this may not hold for individual companies and regions. The period 2008-12 can assist technology investments and diversification, providing the continuation and basic principles of the EU ETS post-2012 is quickly defined and incentives are in place for sectors to pursue this