We present the first results of an ongoing program to investigate the kinematic properties of high redshift damped Lyα systems. Because damped Lyα systems are widely believed to be the progenitors of current massive galaxies, an analysis of their kinematics allows a direct test of galaxy formation scenarios. Specifically, the kinematic history of protogalactic gas is a sensitive discriminator a...

In this paper, a formal model for antivirus update agent system is presented based on mobile agent technology and predicate/transition Petri nets. The mobile agent system contains two mobile agents called DCA and UNA. It sends out agents to update antivirus on client computers in a network. Each agent takes on a specified responsibility. First, DCA roams through the network and check the last d...

For FRF based model updating procedures, the selection of updating frequencies and the choice of a damping approach are important factors to obtain reliable updating resuns. This paper discusses the selection of the updating frequencies and shows that damping approaches like proportional, structural or modal damping are not satisfactory for model updating purposes.