The prints of the Palomar Sky Survey, luminosity classification and radial velocities were used to assign all northern Shapley-Ames galaxies to either (1) field, (2) group, or (3) cluster environments. This information for 930 galaxies shows no evidence for a dependence of bar frequency on galaxy environment. This suggests that the formation of a bar in a disk galaxy is mainly determined by the...

A symbol is a pattern (of physical marks, electromagnetic energy, etc.) which denotes, designates, or otherwise has meaning. The notion that intelligence requires the use and manipulation of symbols, and that humans are therefore symbol systems, has been extremely in uential in arti cial intelligence. keywords: symbol, reasoning, intelligence, representation, logic This article has two parts. W...

By implementing agents and environments using a domain-independent, extensible simulation substrate, described in this paper, agents will have clean interfaces to their environments. These makes it easier for agents to be plugged into other environments that have been similarly defined. If agents can interact with multiple environments, their behaviors and the associated experimental results wi...

Virtual geographic environments (VGE) are environments pertaining to the relationship between post-humans and 3-D virtual worlds. Post-humans are defined as a combination of humans in the real world with 3-D avatars in 3-D virtual worlds. VGE can be a platform for the public participation in spatial data analyses, in model computation and simulation, and in environmental planning and decision m...