Marjory J. Johnson

Learn More
[1] The Panoramic Camera (Pancam) investigation is part of the Athena science payload launched to Mars in 2003 on NASA's twin Mars Exploration Rover (MER) missions. The scientific goals of the Pancam investigation are to assess the high-resolution morphology, topography, and geologic context of each MER landing site, to obtain color images to constrain the(More)
Communication technology now makes it possible to support high data transmission rates at relatively low cost. In particular, optical fiber can be used as the medium in local area networks with data rates in the range of 100 megabits per second. Unfortunately, local area network topologies and communication protocols that work well with lower speed media(More)
Currently there is no control for real-time traffic sources in IP networks. This is a serious problem because real-time traffic can not only congest the network but can also cause unfairness and starvation of TCP traffic. In this paper, a new rate control scheme, RCS, is introduced for real-time traffic in networks with high bandwidth-delay products and(More)
Panoramic Camera images at Gusev crater reveal a rock-strewn surface interspersed with high- to moderate-albedo fine-grained deposits occurring in part as drifts or in small circular swales or hollows. Optically thick coatings of fine-grained ferric iron-rich dust dominate most bright soil and rock surfaces. Spectra of some darker rock surfaces and rock(More)
[1] The Mars Exploration Rover Panoramic Camera (MER/Pancam) instruments have acquired more than 60,000 high-resolution, multispectral, stereoscopic images of soil, rocks, and sky at the Gusev crater and Meridiani Planum landing sites since January 2004. These images, combined with other MER data sets, have enabled new discoveries about the composition,(More)
This paper describes an experiment to prototype a new way of conducting science by applying networking and distributed computing technologies to an Earth Science application. A combination of satellite, wireless, and terrestrial networking provided geologists at a remote field site with interactive access to supercomputer facilities at two NASA centers,(More)
Development of the Next Generation Internet requires the development of revolutionary applications as well as advances in networking technologies. This paper presents experiences in using the NREN testbed to prototype a col-laborative medical-imaging application. Technological requirements for this application include high-bandwidth reliable multicast and(More)