Hubble expansion as a curvature of space

By considering the expansion of space as an additional component of general relativity, a model is described that adds a Hubble curvature term as a new solution to the general equation. Correlation with the $\Lambda$CDM model was assessed using the extensive type~Ia supernovae (SNe~Ia) data with redshift corrected to the CMB, and recent baryonic acoustic oscillation (BAO) measures. For the SNe~Ia data, the modified GR and $\Lambda$CDM models differed by $^{+0.11}_{-0.15}~\mu_B$~mag. over $z_{cmb}=0.01-1.3$, with overall weighted RMS errors of $\pm0.136$ and $\pm0.151$ $\mu_B$~mag respectively. For the BAO measures, the weighted RMS errors were $\pm0.034$ and $\pm0.085$ Mpc with $H_0=67.6\pm0.25$ for the modified GR and $70.0\pm0.25$ for the $\Lambda$CDM models, over the range $z=0.106-2.36$. The derived GR metric accurately describes both the SNe Ia and the baryonic acoustic oscillation (BAO) observations without requiring dark matter or $w$-corrected dark energy while allowing the spatial term to remain flat, suggesting that the standard metric may accept an additional term for the curvature of space due to its Hubble expansion.Comment: 11 pages, 7 figures, submitted to Results in Physic

A comparative study of a communicative process on two wards of a mental hospital.

Thesis (M.A.)--Boston Universit

A multigrid continuation method for elliptic problems with folds

We introduce a new multigrid continuation method for computing solutions of nonlinear elliptic eigenvalue problems which contain limit points (also called turning points or folds). Our method combines the frozen tau technique of Brandt with pseudo-arc length continuation and correction of the parameter on the coarsest grid. This produces considerable storage savings over direct continuation methods,as well as better initial coarse grid approximations, and avoids complicated algorithms for determining the parameter on finer grids. We provide numerical results for second, fourth and sixth order approximations to the two-parameter, two-dimensional stationary reaction-diffusion problem: Δu+λ exp(u/(1+au)) = 0. For the higher order interpolations we use bicubic and biquintic splines. The convergence rate is observed to be independent of the occurrence of limit points

A Comprehensive Experimental Comparison of Event Driven and Multi-Threaded Sensor Node Operating Systems

The capabilities of a sensor network are strongly influenced by the operating system used on the sensor nodes. In general, two different sensor network operating system types are currently considered: event driven and multi-threaded. It is commonly assumed that event driven operating systems are more suited to sensor networks as they use less memory and processing resources. However, if factors other than resource usage are considered important, a multi-threaded system might be preferred. This paper compares the resource needs of multi-threaded and event driven sensor network operating systems. The resources considered are memory usage and power consumption. Additionally, the event handling capabilities of event driven and multi-threaded operating systems are analyzed and compared. The results presented in this paper show that for a number of application areas a thread-based sensor network operating system is feasible and preferable

Improving the Energy Efficiency of the MANTIS Kernel

Event-driven operating systems such as TinyOS are the preferred choice for wireless sensor networks. Alternative designs following a classical multi-threaded approach are also available. A popular implementation of such a multi-threaded sensor network operating system is MANTIS. The event-based TinyOS is more energy efficient than the multi-threaded MANTIS system. However, MANTIS is more capable than TinyOS of supporting time critical tasks as task preemption is supported. Thus, timeliness can be traded for energy efficiency by choosing the appropriate operating system. In this paper we present a MANTIS kernel modification that enables MANTIS to be as power efficient as TinyOS. Results from an experimental analysis demonstrate that the modified MANTIS can be used to fit both sensor network design goals of energy efficiency and timeliness

Doppler radar with multiphase modulation of transmitted and reflected signal

A microwave radar signal is generated and split by a circulator. A phase shifter introduces a series of phase shifts into a first part of the split signal which is then transmitted by antenna. A like number of phase shifts is introduced by the phase shifter into the return signal from the target. The circulator delivers the phase shifted return signal and the leakage signal from the circulator to a mixer which generates an IF signal output at the Doppler frequency. The IF signal is amplified, filtered, counted per unit of time, and the result displayed to provide indications of target sense and range rate. An oscillator controls rate of phase shift in the transmitted and received radar signals and provides a time base for the counter. The phase shift magnitude increases may be continuous and linear or discrete functions of time

digitalnewspapers.org: The Digital Newspapers Program at the University of Utah

Journal ArticleThis article describes the Utah Digital Newspapers Program at the University of Utah's Marriott Library. Background information regarding the historical importance of newspapers, the current state of commercial newspaper digitization and the problems with small newspaper digitization are reviewed, and the solution provided by the University of Utah is offered. Details are provided for the program's history, funding, goals, and future plans. Other topics covered include the trade-offs between microfilm and hard copy source materials, how titles were selected, the processes and technologies utilized, website organization, displaying PDF files with Macintosh computers, and using bi-tonal or grayscale images