Robust estimates in generalized partially linear models

In this paper, we introduce a family of robust estimates for the parametric and nonparametric components under a generalized partially linear model, where the data are modeled by $y_i|(\mathbf{x}_i,t_i)\sim F(\cdot,\mu_i)$ with \mu_i=H(\eta(t_i)+\mathbf{x}_i^{\mathrm{T}}\beta), for some known distribution function F and link function H. It is shown that the estimates of $\beta$ are root-n consistent and asymptotically normal. Through a Monte Carlo study, the performance of these estimators is compared with that of the classical ones.Comment: Published at http://dx.doi.org/10.1214/009053606000000858 in the Annals of Statistics (http://www.imstat.org/aos/) by the Institute of Mathematical Statistics (http://www.imstat.org

Efficiency and power of minimally nonlinear irreversible heat engines with broken time-reversal symmetry

We study the minimally nonlinear irreversible heat engines in which the time-reversal symmetry for the systems may b e broken. The expressions for the power and the efficiency are derived, in which the effects of the nonlinear terms due to dissipations are included. We show that, as within the linear responses, the minimally nonlinear irreversible heat engines enable attainment of Carnot efficiency at positive power. We also find that the Curzon-Ahlborn limit imposed on the efficiency at maximum power can be overcomed if the time-reversal symmetry is broken

Efficiency at maximum power output of an irreversible Carnot-like cycle with internally dissipative friction

We investigate the efficiency at maximum power of an irreversible Carnot engine performing finite-time cycles between two reservoirs at temperatures $T_h$ and $T_c$ $(T_c<T_h)$, taking into account of internally dissipative friction in two "adiabatic" processes. In the frictionless case, the efficiencies at maximum power output are retrieved to be situated between $\eta_{_C}/$ and $\eta_{_C}/(2-\eta_{_C})$, with $\eta_{_C}=1-T_c/{T_h}$ being the Carnot efficiency. The strong limits of the dissipations in the hot and cold isothermal processes lead to the result that the efficiency at maximum power output approaches the values of $\eta_{_C}/$ and $\eta_{_C}/(2-\eta_{_C})$, respectively. When dissipations of two isothermal and two adiabatic processes are symmetric, respectively, the efficiency at maximum power output is founded to be bounded between 0 and the Curzon-Ahlborn (CA) efficiency $1-\sqrt{1-\eta{_C}}$, and the the CA efficiency is achieved in the absence of internally dissipative friction

A case study on a [sic] implementation of marketing data analysis system

This report documents the implementation of a data warehousing initiative for the purpose of marketing data analysis. Implementation of this project was divided into two phases. The objective of phase one is to produce a concept-proof prototype. Phase two, of which I took major responsibility, is to generate an actual production system. Major tasks I performed in phase two covered many aspects of the data warehousing life cycle: revised and fine-tuned the conceptual, logical and physical data model; performed database redesign and database sizing; built and rebuilt the database to improve performance; improved data extraction, transformation and loading process; performed database and SQL performance tuning; planned and implemented information presentation with off the shell data access tools. The first part of the report reviews the data warehousing literature by examining its evolution, conceptual model, major architectural components and some critical issues involved. In the second part of the report, the implementation of a marketing data warehouse is examined in details. A system overview is provided along with the logical data model. It then describes the mainframe component, UNIX components, presentation/end user component and the interaction among them. The Appendix provides further technical details of the project

An experimental study of deep water plunging breakers

Plunging breaking waves are generated mechanically on the surface of essentially deep water in a two‐dimensional wave tank by superposition of progressive waves with slowly decreasing frequency. The time evolution of the transient wave and the flow properties are measured using several experimental techniques, including nonintrusive surface elevation measurement, particle image velocimetry, and particle tracking velocimetry. The wave generation technique is such that the wave steepness is approximately constant across the amplitude spectrum. Major results include the appearance of a discontinuity in slope at the intersection of the lower surface of the plunging jet and the forward face of the wave that generates parasitic capillary waves; transverse irregularities occur along the upper surface of the falling, plunging jet while the leeward side of the wave remains very smooth and two dimensional; the velocity field is shown to decay rapidly with depth, even in this strongly nonlinear regime, and is similar to that expected from linear theory—the fluid is undisturbed for depths greater than one‐half the wavelength; a focusing or convergence of particle velocities are shown to create the jet in the wave crest; vorticity levels determined from the measured, full‐field velocity vectors show that the waves are essentially irrotational until incipient breaking occurs; and the magnitude of the largest water particle velocity is about 30% greater than the phase speed of the (equivalent) linear wave. © 1996 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71298/2/PHFLE6-8-9-2365-1.pd