A Hopfield Network Analog-to-Digital Converter with Hybrid CMOS/Memristor Circuits

Check out some new and cool work we’ve been involved in that was just published in the Frontiers in Neuroscience.

Citation: Xinjie Guo, Farnood Merrikh-Bayat, Ligang Gao, Fabien Alibart, Brian Hoskins, Luke Theogarajan, Christof Teuscher, Bernabe Linares-Barranco, Dmitri Strukov, Modeling and Experimental Demonstration of a Hopfield Network Analog-to-Digital Converter with Hybrid CMOS/Memristor Circuits, Frontiers in Neuroscience, 9(00488), 2015. DOI: http://dx.doi.org/10.3389/fnins.2015.00488

Abstract: The purpose of this work was to demonstrate the feasibility of building recurrent artificial neural networks with hybrid complementary metal oxide semiconductor (CMOS)/memristor circuits. To do so, we modeled a Hopfield network implementing an analog-to-digital converter (ADC) with up to 8 bits of precision. Major shortcomings affecting the ADC’s precision, such as the non-ideal behavior of CMOS circuitry and the specific limitations of memristors, were investigated and an effective solution was proposed, capitalizing on the in-field programmability of memristors. The theoretical work was validated experimentally by demonstrating the successful operation of a 4-bit ADC circuit implemented with discrete Pt/TiO2−x/Pt memristors and CMOS integrated circuit components.

Updated MATLAB Random Boolean Network Toolbox

Andrew Boysen at UPENN is maintaining a more recent and updated branch of our “legacy” MATLAB RBN toolbox. His code is available on GitHub: https://github.com/CSFive/MATLAB_Kauffman_NK_Random_Boolean_Network


Computational capacity and energy consumption of complex resistive switch networks

Check out our latest paper on the “Computational capacity and energy consumption of complex resistive switch networks.” Open access URL: http://dx.doi.org/10.3934/matersci.2015.4.530

The results are relevant for the design and fabrication of novel computing architectures that harness random assemblies of emerging nanodevices.


Jeff presents at 17th Annual SRC TECHCON conference

Three PSU students joined the nation’s top semiconductor scholars and industry leaders to share their research at the Semiconductor Research Corporation’s (SRC) 17th annual TECHCON conference. The conference, held Sept. 20-22 in Austin, Texas, showcased the forefront of semiconductor research and recognized professional and university participants for their contributions to the industry.

tlab student Jeff Udall  was among the 250 undergraduate and graduate students invited from top-flight universities across the country to present their research at the conference. The students from SRC’s Undergraduate Research Opportunities program provides hands-on research and mentorship to attract students to semiconductor industry careers. Their attendance was made possible through the support of Intel Foundation, GLOBALFOUNDRIES, STARnet and SRC Education Alliance.

The papers selected for presentation at TECHCON represent a summary of the best research in SRC’s portfolio across all of the organization’s research programs. To be invited, students submitted an abstract of a research project for review by an SRC-coordinated committee, which selected projects based on rigorous and competitive criteria.

TECHCON brings university students from a variety of science and engineering majors together with scholars and leaders from the semiconductor industry to explore cutting-edge silicon-based research and network with other students and professionals. Altogether, more than 455 attendees participated in the 2015 conference.



New braille, new teaching methods

Project UEB PREP is featured in the Portland State Magazine. UEB PREP is a tlab collaboration with Holly Lawson and Sam Sennott from the PSU Graduate School of Education.


Undergrad research opportunities

Interested to do paid research as an undergraduate? Interested to have a unique experience on your resume? MCECS has a great Undergraduate Research and Mentoring Program (URMP) through which you can get involved in many projects in our lab. Take a look at some sample projects.

The application deadline for the next round is Oct 11, 2015. Please contact me if you are interested.


Former tlab interns join ivy league universities

Former tlab and Saturday Academy ASE summer interns Anusha Asnodkar and Lukas Schwab join ivy league universities. Anusha is studying computer science at Caltech and Lukas at UC Berkeley. Congrats and good luck in your careers!

Lukas Anusha

Publication news (Sep 2015)

  • W. Woods, J. Burger, and C. Teuscher. Synaptic Weight States in a Locally Competitive Algorithm for Neuromorphic Memristive Hardware. IEEE Transactions on Nanotechnology, 2015. DOI: http://dx.doi.org/10.1109/TNANO.2015.2449835. In press.
  • J. Burger, A. Goudarzi, D. Stefanovic, and
    C. Teuscher. Hierarchical Composition of Memristive Networks for Real-Time Computing. Proceedings of the 2015 IEEE/ACM International Symposium on Nanoscale Architectures (NANOARCH), pp 33-38, 2015. DOI: 10.1109/NANOARCH.2015.7180583
  • W. Woods, M. M. A. Taha, D. Tran, J. Burger,
    and C. Teuscher. Memristor Panic — A Survey of Different Device Models in Crossbar Architectures. Proceedings of the 2015 IEEE/ACM International Symposium on Nanoscale Architectures (NANOARCH), pp 106-111, 2015. DOI: 10.1109/NANOARCH.2015.7180595

Immediate Opening: PhD Position in Molecular Computing

The research group of Prof. Christof Teuscher has an immediate opening for a paid PhD student in the area of molecular computing and novel computing paradigms.

Molecular computing is a promising computational paradigm, in which computational functions are evaluated at the nanoscale, with potential applications in smart molecular diagnostics
and therapeutics. However, despite recent advances in the field, prospects for direct application of these techniques to solve real-world problems are limited by the lack of robust interfaces between molecular computers and biological and chemical systems. This project will address these limitations by targeting two application domains, wide-spectrum chemical sensing and
cell surface analysis using molecular logic cascades. Drawing on a combination of experimental, theoretical, and computational tools, molecular computing systems will be developed for use in these application domains. Molecular circuit architectures that process sensor inputs from chemical sensors and cell-surface analysis reactions will be designed, modeled, and implemented in the laboratory, and computational modeling will be used to predict and optimize interactions between DNA circuit components and their binding targets. Furthermore, advanced molecular circuit architectures capable of adaptive, bio-inspired behavior, such as dynamic learning and adaptation, will be designed, with a view to future experimental implementations of these features.

 The position is funded by a new 5-year NSF award. The project is a collaboration with teams from the University of New Mexico and Columbia University.


  • The ideal candidate has experience in DNA and molecular computation, unconventional computation, computational intelligence, machine learning, neural networks, complex systems, and optimization techniques.
  • The candidate must have excellent programming skills, ideally in Java.
  • Other desired qualifications:
    • Masters degree in CS, ECE, or physics.
    • Eligible for PhD program in ECE.
    • Interested in far-reaching, cutting-edge, and interdisciplinary research.
    • Team player.
    • Experience in research environments.
    • Outstanding academic records.
    • Excellent written and verbal communication skills in English.
    • Highly motivated, responsible, independent, with outstanding work ethics. – Visionary, creative, outside-the-box thinker.

How to apply

Please complete the following application form.

The position remains open until filled. Portland State University is an Equal Opportunity/Affirmative Action Employer. Applications from women and minorities are strongly encouraged. Hiring is contingent upon eligibility to work in the US and upon acceptance into the ECE PhD program.


Immediate Opening: Web and mobile developer

WANTED: Web and mobile developer to help build accessibility solution serving individuals who are blind and visually impaired.

The Universal Design Lab and research group of Dr. Holly Lawson, Dr. Samuel Sennott (Education) and Dr. Christof Teuscher (MCECS), have an opening for a graduate research assistant position starting fall 2015. We are looking to connect with passionate students interested in Adaptive Learning, Educational Gaming and Accessibility.

The project is funded by the Rehabilitation Services Administration, Department of Education. Project Unified English Braille through a Powerful and Responsive eLearning Platform (UEB PREP) will design and develop an evidence-based Unified English Braille (UEB) eLearning platform to serve a target population of adult braille users, parents of children who are visually impaired, and professionals (trained and pre-service) who work with individuals who are blind and visually impaired.


  • Excellence in computer programming, particularly Ruby on Rails
  • Team player
  • Self starter
  • Highly motivated, responsible, independent, with outstanding work ethics
  • Excellent academic records
  • Graduate students currently enrolled at PSU

What you will do

  • Help build and design an accessible platform to teach people Braille
  • Integrate educational gaming and social networking
  • Develop web and mobile tools
  • Serve people with disabilities

What you get
A place to invent, design, create, investigate, support and advice, an unconventional lab environment, free coffee, a foosball table, a unique team, opportunities to collaborate with researchers from other fields, opportunity to learn about accessibility through serving individuals with disabilities. For more information, see http://www.universaldesignlab.com.

What we do
The Universal Design Lab (uLab) serves individuals with disabilities through combining good teaching with technology. Past work includes building a top iOS app serving individuals with speech disabilities that was featured on the front page of the NY Times, on 60 Minutes, and in the Wall Street Journal.

The mission of teuscher.:Lab is to study, rethink, model, and design the implementation of computations in living and non-living systems. An understanding of the phenomena provides a basis for better, smarter, and more robust computing paradigms, architectures, devices, algorithms, languages, and systems for applications such as embedded systems and biomolecular engineering. We are interested in bold, visionary, and transformational solutions to complex and critical problems needed for the medium- and long-term sustainability of the technological future of the computing disciplines. For more information, see http://www.teuscher-lab.com

Follow the application instructions below and e-mail your documents to teuscher@pdx.edu. The position remains open until filled.

  • Your complete CV (or resume).
  • A letter of motivation describing why you are interested in this position and how you think you will contribute to the project.
  • Transcripts of all undergraduate and graduate course work. Unofficial transcripts are acceptable.
  • Two (or more) references that can provide recent and applicable feedback on your work capability.

Please do not hesitate to send an inquiry in case of questions.


Next Generation Computing Models and Architectures