Frequency hopping spread spectrum and direct sequence spread spectrum are two main spread coding technologies. Frequency hopping sequences are needed in FH-CDMA systems. In this paper, a construction of optimal sets of frequency hopping sequences is presented via cyclotomy. The construction is based on the set-theoretic characterization of an optimal set of FH sequences. As a consequence, new o...

We study the interplay of Anderson localization and interaction in a two chain Hubbard ladder allowing for arbitrary ratio of disorder strength to interchain coupling. We obtain three different types of spin gapped localized phases depending on the strength of disorder: a pinned 4kF Charge Density Wave (CDW) for weak disorder, a pinned 2kF CDW π for intermediate disorder and two independently p...

We investigated the phenomenon of limb-specific locomotor adaptation in order to adjudicate between sensory-cue-conflict theory and motor-adaptation theory. The results were consistent with cue-conflict theory in demonstrating that two different leg-specific hopping aftereffects are modulated by the presence of conflicting estimates of self-motion from visual and nonvisual sources. Experiment 1...

The control of the hopping height in a one-legged machine is studied. The general aim is to decrease sensitivity of the hopping height to drifts in the machine’s parameters. The proposed approach combines a near-inverse controller which uses height feedback, with a recursive least-squares parameter estimator which continually tunes the controller. The paper presents the mechanical design of the...

Numerical calculations of anisotropic hopping transport based on the resistor network model are presented. Conductivity is shown to follow the stretched exponential dependence on temperature with exponents increasing from 14 to 1 as the wave functions become anisotropic and their localization length in the direction of charge transport decreases. For sufficiently strong anisotropy, this results...

This paper demonstrates the execution and performance of frequency hopping spread spectrum system employing noncoherent frequency shift keyed (NCFSK) modulation. Fast frequency hopping is exploited as a diversity technique over flat Rayleigh fading channel with partial band noise jamming and additive white noise Gaussian (AWGN). The potentiality of the aforementioned system has then, ascertaine...

The number of radio systems operating in the 2.4 GHz band is rising as a result of increased usage of wireless technologies. Since such devices interfere with one another, satisfactory co-existence becomes important. Several techniques serve to reduce the interference. Included among these are frequency hopping (FH) and power control. From the simulation results it can be seen that frequency ho...

In a recent paper, we presented a road map for how Tully's fewest switches surface hopping (FSSH) algorithm can be derived, under certain circumstances, from the mixed quantum-classical Liouville equation. In this communication, we now demonstrate how this new interpretation of surface hopping can yield significantly enhanced results for electronic properties in nonadiabatic calculations. Speci...

We investigate the effects of inelastic cotunneling on the electronic transport properties of gold nanoparticle multilayers and thick films at low applied bias, inside the Coulomb-blockade regime. We find that the zero-bias conductance, g(0)(T), in all systems exhibits Efros-Shklovskii-type variable range hopping transport. The resulting typical hopping distance, corresponding to the number of ...

Results of Monte Carlo simulations for the spinless Falicov–Kimball model with the next-nearest-neighbor hopping are presented. We find the critical value of the next-nearest-neighbor hopping integral, below which the low temperature configuration of the localized particles is the same as in the presence of only the nearest-neighbor hopping. Beyond this critical value the localized particles fo...