In our increasingly mobile world the ability to access information on demand at any time and place can satisfy people's information needs as well as confer on them a competitive advantage. The emergence of battery-operated, low-cost and portable computers such as palmtops and PDAs, coupled with the availability and exploitation of wireless networks, have made possible the potential for ubiquitous computing. Through the wireless networks, portable equipments will become an integrated part of existing distributed computing environments, and mobile users can have access to data stored at...

Nanostructures are among the most actively studied systems in present day - search. Theoretical and experimental studies of these small systems have unc- ered remarkable phenomena due to fundamental interactions and the reduction in dimensionality. Such nanostructures can be made out of well known ma- rials such as metals or semiconductors by lithographic procedures. In addition, novel material systems, e.g. semiconducting heterostructures, or even molecul- like materials, e.g. carbon nanotubes, can represent nanostructures in which electron electron interactions are of importance. The...