A tracker alignment framework for augmented reality

To achieve accurate registration, the transformations which locate the tracking system components with respect to the environment must be known. These transformations relate the base of the tracking system to the virtual world and the tracking system's sensor to the graphics display. In this paper we present a unified, general calibration method for calculating these transformations. A user is asked to align the display with objects in the real world. Using this method, the sensor to display and tracker base to world transformations can be determined with as few as three measurements

Zeroing in on more photons and gluons

We discuss radiation zeros that are found in gauge tree amplitudes for processes involving multi-photon emission. Previous results are clarified by examples and by further elaboration. The conditions under which such amplitude zeros occur are identical in form to those for the single-photon zeros, and all radiated photons must travel parallel to each other. Any other neutral particle likewise must be massless (e.g. gluon) and travel in that common direction. The relevance to questions like gluon jet identification and computational checks is considered. We use examples to show how certain multi-photon amplitudes evade the zeros, and to demonstrate the connection to a more general result, the decoupling of an external electromagnetic plane wave in the ``null zone". Brief comments are made about zeros associated with other gauge-boson emission.Comment: 26 page

Imaging Sources with Fast and Slow Emission Components

We investigate two-proton correlation functions for reactions in which fast dynamical and slow evaporative proton emission are both present. In such cases, the width of the correlation peak provides the most reliable information about the source size of the fast dynamical component. The maximum of the correlation function is sensitive to the relative yields from the slow and fast emission components. Numerically inverting the correlation function allows one to accurately disentangle fast dynamical from slow evaporative emission and extract details of the shape of the two-proton source.Comment: 13 pages, 4 figure

The Energy-Related Inventions Program: Evaluation challenges and solutions

This paper describes results of evaluation of the Energy-Related Inventions Program (ERIP), focusing on the methodological challenges faced by the evaluators and solutions implemented. Operated jointly by US DOE and NIST, ERIP is one of the longest running commercialization assistance programs in US. The evaluation suggest that ERIP is a cost-effective federal investment. By the end of 1994, 24% of ERIP technologies had entered the market, producing total cumulative sales of $961 million (1994 dollars). With$124 million in program appropriations 1975-94, ERIP has an 8:1 return. At least 757 job-years were directly supported by ERIP technologies in 1994, and 6, 646 job-years of employment have been created over the past decade. The sales and employment supported by ERIP technologies are associated with $4.4 million in 1994 federal tax returns. Many issues must be addressed to fairly appraise public investments in technology commercialization programs, such as the need to track the program participants for extended periods, complexities in accounting for spinoff technologies, determining the validity of program evaluations, and dealing with performance data that are dominated by a small number of highly successful technologies

Energy-efficient buildings: Does the marketplace work?

For a variety of reasons, U.S. households, businesses, manufacturers, and government agencies all fail to take full advantage of cost-effective, energy-efficiency opportunities. Despite a growing environmental ethic among Americans and a concern for energy independence, consumers in this country are underinvesting in technologies, products, and practices that would cut their energy bills. The result is a large untapped potential for improving energy productivity, economic competitiveness, environmental quality, and energy security. The thesis of this paper is that the marketplace for energy efficiency, in general, is not operating perfectly, and the marketplace for energy-efficient buildings, in particular, is flawed. The reasons for underinvestments in cost-effective, energy efficiency are numerous and complicated. They also vary from sector to sector: the principal causes of energy inefficiencies in agriculture, manufacturing, and transportation are not the same as the causes of inefficiencies in homes and office buildings, although there are some similarities. One of the reasons for these differences is that the structure of marketplace for delivering new technologies and products in each sector differs. Energy-efficiency improvements in the buildings sector is critical to reducing greenhouse gas emissions, since most of the energy consumed in buildings comes from the burning of fossil fuels. This paper therefore begins by describing energy use and energy trends in the U.S. buildings sector. Characteristics of the marketplace for delivering energy efficiency technologies and products are then described in detail, arguing that this marketplace structure significantly inhibits rapid efficiency improvements

Sodium dependent inositol transport in HL60 cells is not related to Na+/K+, ATPase activity

AbstractIn HL60 cells, inositol transport is sodium-dependent but functionally independent of Na+/K+ ATPase activity. This observation has implications for the currently proposed theory for the development of diabetic complications

Spatial Degrees of Freedom in Everett Quantum Mechanics

Stapp claims that, when spatial degrees of freedom are taken into account, Everett quantum mechanics is ambiguous due to a "core basis problem." To examine an aspect of this claim I generalize the ideal measurement model to include translational degrees of freedom for both the measured system and the measuring apparatus. Analysis of this generalized model using the Everett interpretation in the Heisenberg picture shows that it makes unambiguous predictions for the possible results of measurements and their respective probabilities. The presence of translational degrees of freedom for the measuring apparatus affects the probabilities of measurement outcomes in the same way that a mixed state for the measured system would. Examination of a measurement scenario involving several observers illustrates the consistency of the model with perceived spatial localization of the measuring apparatus.Comment: 34 pp., no figs. Introduction, discussion revised. Material tangential to main point remove

Influence of regional tectonics and pre-existing structures on the formation of elliptical calderas in the Kenyan Rift

Calderas are formed by the collapse of large magma reservoirs and are commonly elliptical in map view. The orientation of elliptical calderas is often used as an indicator of the local stress regime; but, in some rift settings, pre-existing structural trends may also influence the orientation. We investigated whether either of these two mechanisms controls the orientation of calderas in the Kenyan Rift. Satellite-based mapping was used to identify the rift border faults, intra-rift faults and orientation of the calderas to measure the stress orientations and pre-existing structural trends and to determine the extensional regime at each volcano. We found that extension in northern Kenya is orthogonal, whereas that in southern Kenya is oblique. Elliptical calderas in northern Kenya are orientated NW–SE, aligned with pre-existing structures and perpendicular to recent rift faults. In southern Kenya, the calderas are aligned NE–SW and lie oblique to recent rift faults, but are aligned with pre-existing structures. We conclude that, in oblique continental rifts, pre-existing structures control the development of elongated magma reservoirs. Our results highlight the structural control of magmatism at different crustal levels, where pre-existing structures control the storage and orientation of deeper magma reservoirs and the local stress regime controls intra-rift faulting and shallow magmatism. Supplementary material: Details of the Standard Deviation Ellipse function and statistical methods are available at http://www.geolsoc.org.uk/SUP18849