Defense Event

The Logic of Random Pulses: Stochastic Computing

Armin Alaghi

Friday, July 24, 2015
2:00pm - 4:00pm
3725 Beyster Bldg.

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About the Event

Recent developments in the field of electronics has brought about nano-scale devices, whose operation can only be described in probabilistic terms. In contrast with the conventional “deterministic” computing that has dominated the digital world for decades, we investigate a fundamentally different technique that is probabilistic by nature, namely, stochastic computing (SC). In SC, numbers are represented by bit-streams of 0’s and 1’s, in which the probability of seeing a 1 denotes the value of the number. The main benefit of SC is that complex arithmetic computation can be performed by simple logic circuits. For example, a single (logic) AND gate performs multiplication. In this dissertation we begin with a comprehensive survey of SC and its applications. We highlight its main challenges, which include long computation time and low accuracy, as well as the lack of a general design method. We then address all the important challenges. We introduce a new SC circuit design method, called STRAUSS, that generates efficient SC circuits for arbitrary target functions. We then address the problems arising from correlation among stochastic numbers (SNs). In particular, we show that correlation, contrary to general belief, can sometimes serve as a resource in SC circuit design. We also show that unlike conventional circuits, SC circuits can tolerate high error rates and are hence useful in many new applications that involve non-deterministic behavior of the underlying circuitry. Finally, we show how SC’s properties can be exploited in the design of efficient image-processing circuits that are useful in retinal implants.

Additional Information

Sponsor(s): CSE

Faculty Sponsor: John P. Hayes

Open to: Public