Research Info

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Brief Summary of Dissertation Research

For my dissertation, I used probabilistic transfer matrices (PTMs) to compute circuit and system reliabilities (potential yields may be a more accurate description) implemented with electrostatic and magnetic quantum-dot cellular automata (QCA) devices. My goal was to identify the component error rates required to develop reliable circuits. With this knowledge, we can then determine if components with manufacturing defects may be feasible if device level redundancy is used (i.e. thicker electrostatic QCA wires). To do this, I built a new electrostatic QCA simulator and determined the reliability of various electrostatic QCA straight wires given various levels of device redundancy.

Current Projects:

My current research involves two major topics. The first is investigating the use of fat trees as a potential memory organization; within this project I am investigating the routing and traffic loads of these trees. The second project is extending my previous studies on the use of device level redundancy in electrostatic QCA wires. The two main goals of this project are to validate the use of the PTM modeling and to demonstrate the reliability advantages of using thick wires

A project I started working on (but the fat tree work took precedence), was investigating the energy required to access an element of memory in current/future microprocessors. This project was directed towards the results of the DARPA ExaScale Study (study available here).

QCA Background and Links

For reference, a basic introduction to electrostatic QCA can be found on the QCADesigner website here. Magnetic QCA is similar in nature to electrostatic QCA if you consider a single magnet to be roughly equivalent to half of an electrostatic cell (differences occur in the majority gates and vertical wire structures). Since QCA is a misnomer for the magnetic implementation, the term nanomagnetic logic (NML) is being utilized instead. A large number of papers (and references to many more) can be found here or here.

Note: I would highly encourage anyone with questions on QCA and/or QCADesigner to join the Yahoo group qca_design and post their question to that list. Links to the group page and joining the mailing list can be found at the QCADesigner website (link here).

Publications:

QCADesigner Contributions:

Note: The above contributions have not been introduced into the release versions of QCADesigner at the discretion of its caretakers. The XML file format components are included here and I may still have a version of QCADesigner with a digital logic simulation method, but I'm not certain. At the very least, I have a stand alone version of the digital logic simulation engine.