ECE- Monographs, Research and Papers
http://hdl.handle.net/1813/10159
2016-07-27T06:08:09ZA Reconfigurable Analog Substrate for Highly Efficient Maximum Flow Computation
http://hdl.handle.net/1813/41513
A Reconfigurable Analog Substrate for Highly Efficient Maximum Flow Computation
Liu, Gai; Zhang, Zhiru
We present the design and analysis of a novel analog reconfigurable substrate that enables fast and efficient computation of maximum flow on directed graphs. The substrate is composed of memristors and standard analog circuit components, where the on/off states of the crossbar switches encode the graph topology. We show that upon convergence, the steady-state voltages in the circuit capture the solution to the maximum flow problem. We also propose techniques to minimize the impacts of variability and non-ideal circuit components on the solution quality, enabling practical implementation of the proposed substrate. Our performance evaluation indicates two to three orders of magnitude improvements in speed and energy efficiency compared to a standard CPU implementation. In the last part of this report, we also discuss the major limitations of the current design, and suggest promising research directions.
2015-12-01T00:00:00ZTwo-Hop Interference Channels Impact of Linear Time-Varying Schemes
http://hdl.handle.net/1813/31515
Two-Hop Interference Channels Impact of Linear Time-Varying Schemes
Issa, Ibrahim; Fong, Silas L.; Avestimehr, Salman
We consider the two-hop interference channel (IC) with constant channel coefficients, which consists of two source-destination pairs, separated by two relays. We analyze the achievable degrees of freedom (DoF) of such network when relays are restricted to perform scalar amplify-forward (AF) operations, with possibly time-varying coefficients. We show that, somewhat surprisingly, by providing the flexibility of choosing time-varying AF coefficients at the relays, it is possible to achieve 4/3 sum-DoF. We also develop a novel outerbound that matches our achievability, hence characterizing the sum-DoF of two-hop interference channels with time-varying AF relaying strategies.
2013-02-26T00:00:00Z