Copyright, Culture, and Community in Virtual Worlds

Communities that interact on-line through computer games and other virtual worlds are mediated by the audiovisual content of the game interface. Much of this content is subject to copyright law, which confers on the copyright owner the legal right to prevent certain unauthorized uses of the content. Such exclusive rights impose a limiting factor on the development of communities that are situated around the interface content, because the rights, privileges, and\ud exceptions associated with copyright generally tend to disregard the cultural significance of copyrighted content. This limiting effect of copyright is well illustrated by examination of the copied content appropriated by virtual diaspora communities from the game Uru: Ages of Myst. Reconsideration of current copyright law would be required in order to accommodate the cohesion of on-line\ud communities and related cultural uses of copyrighted content

Transport models for numerical forecast

The explosive growth of computing power, coupled with scientific and technological emphasis on a national scale, has led to significant major advances in operational numerical weather prediction (NWP) during the last two decades. There are about half a dozen major centers around the world running global NWP models operationally. Many more countries have operational hemispheric or limited-area models which provide weather forecasts. The global models typically have several hundred kilometer resolution, while the limited-area models usually have horizontal spacing of 50 to 100 km. Given the pace of burgeoning growth in this area, it seems warranted to occasionally take an overview of aspects of the field common to all modelers. Here, a brief look is taken at the nature of subgrid scale turbulence transport parameterization, and some of the difficulties pertaining thereto, with particular emphasis on operational NWP models

Exploratory wind-tunnel investigation of deployable flexible ventral fins for use as an emergency spin-recovery device

Spin tunnel tests to determine effectiveness of deployable, flexible ventral fins for spin recovery device on fighter aircraf

An interactive graphics system to facilitate finite element structural analysis

The characteristics of an interactive graphics systems to facilitate the finite element method of structural analysis are described. The finite element model analysis consists of three phases: (1) preprocessing (model generation), (2) problem solution, and (3) postprocessing (interpretation of results). The advantages of interactive graphics to finite element structural analysis are defined

Received optical power calculations for optical communications link performance analysis

The factors affecting optical communication link performance differ substantially from those at microwave frequencies, due to the drastically differing technologies, modulation formats, and effects of quantum noise in optical communications. In addition detailed design control table calculations for optical systems are less well developed than corresponding microwave system techniques, reflecting the relatively less mature state of development of optical communications. Described below are detailed calculations of received optical signal and background power in optical communication systems, with emphasis on analytic models for accurately predicting transmitter and receiver system losses

Enhancement of the CAVE computer code

The computer code CAVE (Conduction Analysis via Eigenvalues) is a convenient and efficient computer code for predicting two dimensional temperature histories within thermal protection systems for hypersonic vehicles. The capabilities of CAVE were enhanced by incorporation of the following features into the code: real gas effects in the aerodynamic heating predictions, geometry and aerodynamic heating package for analyses of cone shaped bodies, input option to change from laminar to turbulent heating predictions on leading edges, modification to account for reduction in adiabatic wall temperature with increase in leading sweep, geometry package for two dimensional scramjet engine sidewall, with an option for heat transfer to external and internal surfaces, print out modification to provide tables of select temperatures for plotting and storage, and modifications to the radiation calculation procedure to eliminate temperature oscillations induced by high heating rates. These new features are described

An automatic system for determining solar absorptance and thermal emittance of surfaces from spectral normal reflectance measurements

Spectrophotometers, digitizer, and computer system to determine solar absorptance and thermal emittance of surfaces from spectral reflectance measurement

Low-speed dynamic model investigation of Apollo command module configurations in the Langley spin tunnel

Dynamic stability of Apollo command module with and without drogue parachutes at low subsonic speeds in spin tunne

Magnetic ordering of nitrogen-vacancy centers in diamond via resonator-mediated coupling

Nitrogen-vacancy centers in diamond, being a promising candidate for quantum information processing, may also be an ideal platform for simulating many-body physics. However, it is difficult to realize interactions between nitrogen-vacancy centers strong enough to form a macroscopically ordered phase under realistic temperatures. Here we propose a scheme to realize long-range ferromagnetic Ising interactions between distant nitrogen-vacancy centers by using a mechanical resonator as a medium. Since the critical temperature in the long-range Ising model is proportional to the number of spins, a ferromagnetic order can be formed at a temperature of tens of millikelvin for a sample with $\sim10^4$ nitrogen-vacancy centers. This method may provide a new platform for studying many-body physics using qubit systems.Comment: 5 pages, 4 figure