From a hopping rate equation for disordered materials we derive a macroscopic drift{di usion equation. For this purposes two space{time scales are simultaneously considered. The microscopic dynamics is characterized by the distribution of localized states and the hopping rate. On the macroscopic space scale both the hopping rate and the disordered material are allowed to be inhomogeneous.

Spread-spectrum (SS) communications technology was first described on paper by an actress and a musician! In 1941, Hollywood actress Hedy Lamarr and pianist George Antheil described a secure radio link to control torpedos and received U.S. patent #2.292.387. It was not taken seriously at that time by the U.S. Army and was forgotten until the 1980s, when the came alive, and has become increasing...

The phenomenon of protein synthesis has been modeled in terms of totally asymmetric simple exclusion processes (TASEP) since 1968. In this article, we provide a tutorial of the biological and mathematical aspects of this approach. We also summarize several new results, concerned with limited resources in the cell and simple estimates for the current (protein production rate) of a TASEP with inh...

Our previous results [J.Phys.: Condens. Matter 14 (2002) 13777] dealing with the analytical solution of the two-dimensional (2-D) Anderson localization problem due to disorder is generalized for anisotropic systems (two different hopping matrix elements in transverse directions). We discuss the mathematical nature of the metalinsulator phase transition which occurs in the 2-D case, in contrast ...

A new formulation of total unsharpness in radiography based on line spread and edge spread function analysis is established and investigated. The unsharpness contributions due to (1) screen conversion, (2) object motion and (3) geometric effects are incorporated into a general integral formulation. Comparisons with experiments are undertaken and the ambiguity, as well as limitation, of a widely...

In this paper a new kind of hopping robot has been designed which uses inverse pendulum dynamics to induce bipedal hopping gaits. Its mechanical structure consists of a rigid inverted T-shape mounted on four compliant feet. An upright “T” structure is connected to this by a rotary joint. The horizontal beam of the upright “T” is connected to the vertical beam by a second rotary joint. Using thi...

The nature of packet loss of wireless links at 2.4G band was analyzed and a wireless link quality prediction algorithm for wireless sensor networks was proposed. In the proposal, RSSI (Received Signal Strength Indicator) and LQI (Link Quality Indicator) were utilized to produce a couple of metrics of wireless link quality, named Sm and delta respectively, and their distributions were studied. B...

Wind velocity and slope are two critical variables that affect wildland fire rate of spread. The effects of these variables on rate of spread are often combined in rate-of-spread models using vector addition. The various methods used to combine wind and slope effects have seldom been validated or compared due to differences in the models or to lack of data. In this study, rate-of-spread predict...