SRI International

About: SRI International is a nonprofit organization based out in Menlo Park, California, United States. It is known for research contribution in the topics: Ionosphere & Laser. The organization has 7222 authors who have published 13102 publications receiving 660724 citations. The organization is also known as: Stanford Research Institute & SRI.

The Weak Byzantine Generals Problem

Abstract: The Byzantine Generals Problem requires processes to reach agreement upon a value even though some of them may fad. It is weakened by allowing them to agree upon an "incorrect" value if a failure occurs. The transaction eormmt problem for a distributed database Js a special case of the weaker problem. It is shown that, like the original Byzantine Generals Problem, the weak version can be solved only ff fewer than one-third of the processes may fad. Unlike the onginal problem, an approximate solution exists that can tolerate arbaranly many failures.

Two-band model of heterochromatic flicker

Abstract: We have attempted to reconcile the results of several recent chromatic flicker studies. By adjusting the relative amplitudes of red and green sine-wave stimuli that were flickering in opposite phase, we obtained conditions varying from purely chromatic (red–green) stimulation, through each “silent-cone” condition, to purely luminous (homochromatic) stimulation. We also tested the effects of adapting backgrounds in each condition. Our results can be explained in terms of a low-frequency band that represents the opponent-color response, and a high-frequency band that represents the achromatic response. These two bands respond in various proportions, depending on the red–green stimulus ratio. Chromatic adaptation generally affects the low- and high-frequency bands differently and hence changes the shape of the flicker sensitivity curve. However, if the temporally varying waveform and the adapting background are both chosen to stimulate the same cone type, then the opponent-color and achromatic bands are both attenuated by the same amount. In this case, the shapes of the silent-red and silent-green flicker curves are preserved under chromatic adaptation. We conclude that none of these flicker curves are controlled by the temporal characteristics of independent cone types.

Applications of dielectric elastomer actuators

Abstract: Dielectric elastomer actuators, based on the field-induced deformation of elastomeric polymers with compliant electrodes, can produce a large strain response, combined with a fast response time and high electromechanical efficiency. This unique performance, combined with other factors such as low cost, suggests many potential applications, a wide range of which are under investigation. Applications that effectively exploit the properties of dielectric elastomers include artificial muscle actuators for robots; low-cost, lightweight linear actuators; solid- state optical devices; diaphragm actuators for pumps and smart skins; acoustic actuators; and rotary motors. Issues that may ultimately determine the success or failure of the actuation technology for specific applications include the durability of the actuator, the performance of the actuator under load, operating voltage and power requirements, and electronic driving circuitry, to name a few.