A Rapid Emergency Deployment mobile communication node

In an Emergency and/or Crisis Situations (ECS) like earthquakes, floods, tsunamis, fires, terrorist attacks etc. the adequate operation of communication services is of extreme importance. History has shown that poor communication in such cases resulted in several casualties. In ECS fixed communication infrastructure might be unserviceable due to sustained damages. Evermore, the communication demand is highly increased in such cases resulting in poor quality of service as both civilians and authorities are trying to establish communications. In this paper, a Rapid Emergency Deployment mobile Communication (REDComm) node is presented. REDComm nodes include wireless communication technologies, to provide various telecommunication services in ECS and interoperability between them. It incorporates an 802.11a mesh cognitive radio technology that operates in the television broadcasting frequency bands to provide a backbone networking with increased range and flexibility. REDComm is constructed upon a trailer chassis able to minimize setup time, which is valuable in ECS. The presented platform is powered by a hybrid power source that combines thermal, solar and wind energy and eliminates the need for external power supply

Double-Layer Systems at Zero Magnetic Field

We investigate theoretically the effects of intralayer and interlayer exchange in biased double-layer electron and hole systems, in the absence of a magnetic field. We use a variational Hartree-Fock-like approximation to analyze the effects of layer separation, layer density, tunneling, and applied gate voltages on the layer densities and on interlayer phase coherence. In agreement with earlier work, we find that for very small layer separations and low layer densities, an interlayer-correlated ground state possessing spontaneous interlayer coherence (SILC) is obtained, even in the absence of interlayer tunneling. In contrast to earlier work, we find that as a function of total density, there exist four, rather than three, distinct noncrystalline phases for balanced double-layer systems without interlayer tunneling. The newly identified phase exists for a narrow range of densities and has three components and slightly unequal layer densities, with one layer being spin polarized, and the other unpolarized. An additional two-component phase is also possible in the presence of sufficiently strong bias or tunneling. The lowest-density SILC phase is the fully spin- and pseudospin-polarized ``one-component'' phase discussed by Zheng {\it et al.} [Phys. Rev. B {\bf 55}, 4506 (1997)]. We argue that this phase will produce a finite interlayer Coulomb drag at zero temperature due to the SILC. We calculate the particle densities in each layer as a function of the gate voltage and total particle density, and find that interlayer exchange can reduce or prevent abrupt transfers of charge between the two layers. We also calculate the effect of interlayer exchange on the interlayer capacitance.Comment: 35 pages, 19 figures included. To appear in PR

Academic Entrepreneurship, Innovation Policies and Politics in Greece

This paper explores the process of the emergence in Greece of the 'Triple Helix', and the nature of the 'Helix' in the context of the concurrent changes occurring in Greek socio-political affairs. The influence of politics and innovation policies on the relationships between academia and government and industry is considered. Emphasis is given to national and regional innovation policies and their impact on the commercialization of academic research in the National Technical University of Athens, the University of Thessaly and the Foundation for Research and Technology — Hellas (FORTH) in Crete