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—We describe a secure communication scheme that uses the random fluctuation of the natural environment of communication channels. Only the transmitter and the receiver share the communication channel characteristics. From reciprocity between a transmitter and a receiver, it is possible for them to share one-time information of their fluctuating channel.(More)
– Analog approaches are expected to offer dramatically low power consumption in smart antennas, especially for battery-operated wireless terminal devices. This paper overviews recently developed analog antenna techniques for smart beamforming. Hardware architectures, trained-and blind-control criteria, and adaptation algorithms are introduced along with(More)
Principle, control theory, and application of the ESPAR (Electrically Steerable Parasitic Array Radiator) antenna are introduced. A typical ESPAR antenna consists of monopole or dipole elements, one of which is the radiator (fed element) and the others are the parasitic radiators with variable reactance devices loaded on them. It can provide a lower-cost(More)
The effect of microgravity on skeletal muscles has so far been examined in rat and mice only after short-term (5-20 day) spaceflights. The mice drawer system (MDS) program, sponsored by Italian Space Agency, for the first time aimed to investigate the consequences of long-term (91 days) exposure to microgravity in mice within the International Space(More)
—A low-power consumption, small-size smart antenna, named electronically steerable parasitic array radiator (ESPAR), has been designed. Beamforming is achieved by tuning the load reactances at parasitic elements surrounding the active central element. A fast beamforming algorithm based on simultaneous perturbation stochastic approximation with a maximum(More)
The objective of the beamforming with the exploitation of a sensor array is to enhance the signals of the sources from desired directions, suppress the noises and the interfering signals from other directions, and/or simultaneously provide the localization of the associated sources. In this paper, we present a higher order cumulant-based beamforming(More)
Hormonal changes in humans during spaceflight have been demonstrated but the underlying mechanisms are still unknown. To clarify this point thyroid and testis/epididymis, both regulated by anterior pituitary gland, have been analyzed on long-term space-exposed male C57BL/10 mice, either wild type or pleiotrophin transgenic, overexpressing osteoblast(More)