6,822 research outputs found
On the Fictitious Play and Channel Selection Games
Considering the interaction through mutual interference of the different
radio devices, the channel selection (CS) problem in decentralized parallel
multiple access channels can be modeled by strategic-form games. Here, we show
that the CS problem is a potential game (PG) and thus the fictitious play (FP)
converges to a Nash equilibrium (NE) either in pure or mixed strategies. Using
a 2-player 2-channel game, it is shown that convergence in mixed strategies
might lead to cycles of action profiles which lead to individual spectral
efficiencies (SE) which are worse than the SE at the worst NE in mixed and pure
strategies. Finally, exploiting the fact that the CS problem is a PG and an
aggregation game, we present a method to implement FP with local information
and minimum feedback.Comment: In proc. of the IEEE Latin-American Conference on Communications
(LATINCOM), Bogota, Colombia, September, 201
Room-Temperature Continuous-Wave Vertical-Cavity Single-Quantum-Well Microlaser Diodes
Room-temperature continuous and pulsed lasing of vertical-cavity, single-quantum-well, surface-emitting microlasers is achieved at ~983nm. The active Ga[sub][0-8]In[sub][0-2]As single quantum well is 100 [angstroms] thick. These microlasers have the smallest gain medium volumes among lasers ever built. The entire laser structure is grown by molecular beam epitaxy and the microlasers are formed by chemically assisted ion-beam etching. The microlasers are 3-50-Îźm across. The minimum threshold currents are 1.1 mA (pulsed) and 1.5 mA (CW)
Notes on the melittofauna from La Tatacoa Desert, Huila, Colombia
We present a checklist of the melittofauna from La Tatacoa Desert, Department of Huila, a remnant of highly disturbed tropical dry forest located in the upper valley of the Magdalena River. The list consists of 33 species in 20 genera of three families. The most abundant species was the emphorine bee Melitomella schwarzi (Michener, 1954), which accounted for 43% of the specimens collected. Exomalopsis (Phanomalopsis) trifasciata Brèthes, 1910 and Paratetrapedia connexa (Vachal, 1909) are newly recorded for Colombia.Facultad de Ciencias Naturales y Muse
Low-Threshold Electrically Pumps Vertical-Cavity Surface-Emitting Microlasers
Vertical-cavity electrically driven lasers with three GaInAs
quantum wells and diameters of several Îźm exhibit room-temperature pulsed current thresholds as low as 1.3mA with 958 nm output wavelength
Effects of rf Current on Spin Transfer Torque Induced Dynamics
The impact of radiofrequency (rf) currents on the direct current (dc) driven
switching dynamics in current-perpendicular-to-plane nanoscale spin valves is
demonstrated. The rf currents dramatically alter the dc driven free layer
magnetization reversal dynamics as well as the dc switching level. This occurs
when the frequency of the rf current is tuned to a frequency range around the
dc driven magnetization precession frequencies. For these frequencies,
interactions between the dc driven precession and the injected rf induce
frequency locking and frequency pulling effects that lead to a measurable
dependence of the critical switching current on the frequency of the injected
rf. Based on macrospin simulations, including dc as well as rf spin torque
currents, we explain the origin of the observed effects.Comment: 5 pages, 4 figure
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