Decomposition tables for experiments. II. Two--one randomizations

We investigate structure for pairs of randomizations that do not follow each other in a chain. These are unrandomized-inclusive, independent, coincident or double randomizations. This involves taking several structures that satisfy particular relations and combining them to form the appropriate orthogonal decomposition of the data space for the experiment. We show how to establish the decomposition table giving the sources of variation, their relationships and their degrees of freedom, so that competing designs can be evaluated. This leads to recommendations for when the different types of multiple randomization should be used.Comment: Published in at http://dx.doi.org/10.1214/09-AOS785 the Annals of Statistics (http://www.imstat.org/aos/) by the Institute of Mathematical Statistics (http://www.imstat.org

Apparatus and method for protecting a photographic device Patent

Camera protecting device for use in photographing rocket engine nozzles or other engine component

Decomposition tables for experiments I. A chain of randomizations

One aspect of evaluating the design for an experiment is the discovery of the relationships between subspaces of the data space. Initially we establish the notation and methods for evaluating an experiment with a single randomization. Starting with two structures, or orthogonal decompositions of the data space, we describe how to combine them to form the overall decomposition for a single-randomization experiment that is ``structure balanced.'' The relationships between the two structures are characterized using efficiency factors. The decomposition is encapsulated in a decomposition table. Then, for experiments that involve multiple randomizations forming a chain, we take several structures that pairwise are structure balanced and combine them to establish the form of the orthogonal decomposition for the experiment. In particular, it is proven that the properties of the design for such an experiment are derived in a straightforward manner from those of the individual designs. We show how to formulate an extended decomposition table giving the sources of variation, their relationships and their degrees of freedom, so that competing designs can be evaluated.Comment: Published in at http://dx.doi.org/10.1214/09-AOS717 the Annals of Statistics (http://www.imstat.org/aos/) by the Institute of Mathematical Statistics (http://www.imstat.org

Adaptive control system for line-commutated inverters

A control system for a permanent magnet motor driven by a multiphase line commutated inverter is provided with integration for integrating the back EMF of each phase of the motor. This is used in generating system control signals for an inverter gate logic using a sync and firing angle (alpha) control generator connected to the outputs of the integrators. A precision full wave rectifier provides a speed control feedback signal to a phase delay rectifier via a gain and loop compensation circuit and to the integrators for adaptive control of the attenuation of low frequencies by the integrators as a function of motor speed. As the motor speed increases, the attenuation of low frequency components by the integrators is increased to offset the gain of the integrators to spurious low frequencies

Investigating the appropriateness and relevance of mobile web accessibility guidelines

The Web Accessibility Initiative (WAI) of the World Wide Web Consortium (W3C) develop and maintain guidelines for making the web more accessible to people with disabilities. WCAG 2.0 and the MWBP 1.0 are internationally regarded as the industry standard guidelines for web accessibility. Mobile testing sessions conducted by AbilityNet document issues raised by users in a report format, relating issues to guidelines wherever possible. This paper presents the results of a preliminary investigation that examines how effectively and easily these issues can be related by experts to the guidelines provided by WCAG 2.0 and MWBP 1.0. Copyright 2014 ACM

High temperature static strain sensor development program

Electrical resistance strain gages useful for static strain measurements on nickel or cobalt superalloy parts inside a gas turbine engine on a test stand are being developed. Measurements of this type are of great importance in meeting the goals of the HOST program because, without reliable knowledge of the stresses and strains which exist in specific components, it will be difficult to fully appreciate where improvements in design and materials can be implemented. The first part of the effort consisted of a strain gage alloy development program which will be followed by an investigation of complete strain gage systems which will use the best of the alloys developed together with other system improvements

Design and application of polycarbonate capacitors in aerospace ac power systems

Design and testing of ac polycarbonate capacitors for aerospace power system

Electronic compensation for reflector surface distortion to improve radiation pattern characteristics of antennas

A simple procedure is described for determining the excitation coefficients of an array feed which compensates for the surface distortion of a reflector antenna to improve the radiation pattern in such a way as to approximate the performance of the undistorted antenna. A computer simulation for a practical feed array is presented as an example of compensation for the distortion of an actual antenna