This paper presents a landmark-oriented visual navigation system for unmanned vehicles (UMVs). An extensible knowledge-based parser is implemented through a syntactic approach for the recognition of T-junctions and crossroads of corridors. In addition, both geometrical perspective and flat-earth models are adopted to estimate the distances from objects to the front of a UMV. With our steering c...

Observational tests during the next decade may determine if the evolution of the Universe can be understood from fundamental physical principles, or if special initial conditions, coincidences, and new, untestable physical laws must be invoked. The inflationary model of the Universe is an important example of a predictive cosmological theory based on physical principles. In this talk, we discus...

As they say, all good things must come to an end. After years of record profits and soaring subscriber numbers, the U.S. wireless market is now becoming saturated, with over 90% of adults in the U.S. owning a cell phone, according to Pew Research Center. The heady growth cannot continue without another swell of innovation spurring new sales, which does not appear immediately forthcoming. Pundit...

14 Spring 2010/ Vol. 16, No. 3 www.acm.org/crossroads Crossroads Besides public data repositories, scientific collaborations maintain community-wide data resources. For example, in gravitational-wave physics, the Laser Interferometer Gravitational-Wave Observatory [3] maintains geographically distributed repositories holding time-series data collected by the instruments and their associated met...