Team ECE Receives Best Paper Award at ISLPED 2017

A paper presented by ECE graduate student Muqing Liu, and co-authored by an all-ECE team (Muqing Liu, Chen Zhou, Qianying Tang, Prof. Keshab Parhi, and Prof. Chris Kim) has been selected for the best paper award at the 2017 International Symposium on Low Power Electronics and Design (ISLPED), a key conference on low power circuits and systems.

Titled “A Data Remanence based Approach to Generate 100% Stable Keys from an SRAM Physical Unclonable Function,” the paper’s authors have been recognized with the best paper award two years in a row, which is rather unusual for this conference. The paper proposes a method that is more effective in finding the most stable cells in a large SRAM array.

SRAM is an attractive circuit for generating encryption keys because the start-up value of an SRAM cell is unique, random, and unclonable. However, the primary challenge for SRAM based key generation, however, is poor stability when the circuit is subject to random noise, temperature and voltage changes, and device aging. Earlier papers have suggested the use of temporal majority voting (TMV) and bit masking to identify and store the location of unstable or marginally stable SRAM cells. However, TMV requires a long test time and significant hardware resources. In addition, the number of repetitive power-ups required to find the most stable cells is prohibitively high.

The authors developed a one-time highly efficient data remanence based test method that can identify the most stable bits in an SRAM array for reliable key generation. The approach only requires two tests to identify all the stable ‘0’s and ‘1’s, which is more efficient than the popular temporal majority voting (TMV) technique. Experimental studies have shown that the 256-bit key generated from a 512 kbit SRAM using the proposed data remanence method is 100% stable under different temperatures, power ramp up times, and device aging.

The work was jointly funded by the National Science Foundation and the Semiconductor Research Corporation.

Alumnus Michael Roman Appointed COO of 3M

Alumnus Michael Roman has been appointed Chief Operating Officer and Executive Vice-President of Maplewood, Minnesota-based multinational corporation, 3M. A 25-year veteran of the Minnesota-based company, Roman will report directly to the Chairman, President, and CEO Inge Thulin. The appointment was effective July 1, 2017.

Roman earned his B.E.E. degree in the Department of Electrical and Computer Engineering at the University of Minnesota in 1982, and his master’s degree in 1987 from the University of Southern California. Over the years, Roman has taken on roles of successively greater technical and managerial leadership. He has held positions such as Technical Manager, Project Manager of Intelligent Transportation Systems, and Six Sigma Director of Safety, Security and Protection Services Business Center.

In more recent years, his roles have included Managing Director of 3M Korea, Vice President of Business Development – Optical Systems Division, Asia, and  Vice President and General Manager of Industrial Adhesives and Tapes Division. In his latest role before being appointed COO, Roman served as  Executive Vice President of Industrial Business Group, 3M’s largest business group.  

As Chief Operating Officer, he will oversee the company’s international operations as well as its five business groups (consumer, electronics and energy, health care, industrial, and safety and graphics).

A thorough midwesterner, Roman has continued his ties with his alma mater. He serves on the University of Minnesota Foundation’s Board of Trustees as Treasurer. The members of the board are “responsible for providing governance, advocacy, and philanthropic support to advance the mission of the Foundation.” (


Prof. Keshab Parhi Receives IEEE CAS Mac Van Valkenburg Award

The IEEE Circuits and Systems Society has awarded ECE’s Prof. Keshab Parhi the Mac Van Valkenburg Award for pioneering contributions to VLSI digital signal processing architectures, design methodologies, and their applications to wired and wireless communications, and service to IEEE Circuits and Systems Society.

The Mac Van Valkenburg Award honors individuals for outstanding technical contributions and distinguishable leadership in a field within the scope of the Circuits and Systems Society. The award is based on the quality and significance of contribution, and continuity of technical leadership.

Prof. Parhi has made significant and long-lasting impacts through his seminal and pioneering research in the broad field of Very Large Scale Integrated (VLSI) design of digital signal processing, image processing and communications systems. His research is used in many integrated circuit chips for broadband communications systems that form the backbone of the internet. Examples include gigabit ethernet and 10-gigabit ethernet on copper and fiber cables, cable modems, settop boxes, chip-to-chip communication in backplanes and serializers-deserializers (a.k.a. serdes), cell phones, and storage systems. He is widely recognized for his pioneering work on pipelining and parallel processing of numerous recursive computations such as decision-feedback equalizers and Tomlinson-Harashima precoders using various look-ahead techniques. He developed the theory of folding and
unfolding transformations for data-flow graphs that describe digital signal processing programs. He also authored the text book: VLSI Digital Signal Processing Systems (John Wiley and Sons, 1999). He is the author of over 600 papers and inventor or coinventor of 29 US patents.

Prof. Parhi has served the IEEE Circuits and Systems (CAS) society in numerous capacities. He was the Editor-in-Chief of the IEEE Transactions on Circuits and Systems, Part-I during 2004 and 2005. He has served in Associate Editor capacity for various journals 14 times. He served on the Board of Governors of the CAS society during 2005-2007. He was Chair of the Technical Committee on VLSI Systems and Applications during 2003 and 2004, and a founding member of the Nano-Giga Technical Committee of the IEEE CAS society. Previously, Prof. Parhi was awarded the 2012 Charles A. Desoer Technical Achievement award and a 2000 Golden Jubilee Medal from the IEEE CAS Society. He also received the 2003 Kiyo Tomiyasu Technical Field award from the IEEE and the 2004 Frederick Emmons Terman award from the American Society of Engineering Education.

Prof. Parhi, along with his former doctoral student Yingjie Lao (now faculty at Clemson University), is also the recipient of the 2017 IEEE VLSI Best Paper Award. The paper “Obfuscating DSP Circuits via High-Level Transformations,” was published in the IEEE Transactions on Very Large Scale Integration (VLSI) Systems in the May 2015 issue.

This paper presents a novel approach to the design of obfuscated circuits for digital signal processing (DSP) applications using high-level transformations, a key-based obfuscating finite-state machine (FSM), and a reconfigurator. The goal is to design DSP circuits that are harder to reverse engineer thereby protecting the designer’s intellectual property. Typically, a hacker determines the functionality of a DSP circuit in one of two ways: either by structural analysis to isolate the original design, or by simulation-based reverse engineering to determine functionality of the design.

To protect DSP circuits against reverse engineering, the obfuscated circuits will only operate in the desired mode with a negligible probability that others would be able to find. Thus, the correct functionality is hidden to the adversary even when the adversary can access the DSP circuits. For details, read the award-winning paper here.

ECE Alumnus is 2017 CSE Commencement Speaker

Grant Erickson, ECE alumnus, is the CSE Commencement speaker for 2017. He is a principal engineer at Nest Labs where he oversees the technical development of platform software designed to support Bluetooth Low Energy, Thread, WiFi, and Weave. He played an active role in the formation of the Thread Group and Thread networking protocol, and is currently president of the Thread Group.

You can read a detailed biographical sketch on Grant here.

Grant earned his bachelor’s, and master’s degrees in 1996 and 1998 from the Department of Electrical and Computer Engineering at the University of Minnesota. He led the San Francisco Bay Area chapter of the University of Minnesota Alumni Association for 16 years. He currently resides in Sunnyvale with his wife Jessica, daughter Grace, and golden doodle Charlie. Some of Grant’s other passions include architecture and design, playing the guitar, and travel.

In fall 2015, we had featured an interview with Grant on the challenges and opportunities of living in a connected world. You can read the interview “IoT: opportunities, concerns, and challenges” here.

In the Spotlight: Prof. Bethanie Stadler

In the summer of this year, ECE’s Prof. Bethanie Stadler will be making her way to the Kingdom of Saudi Arabia as part of a collaborative research project with King Abdullah University of Science and Technology (KAUST). She is one of an international 4-person team which includes C-SPIN director and ECE faculty Prof. Jian-Ping Wang, and Profs. Jürgen Kosel and Aurelien Manchon of KAUST, who will work on developing novel memory devices that can provide high memory density combined with low power consumption per bit.

The opportunity stemmed from Prof. Stadler’s global lecture tour, which included Saudi Arabia, as an IEEE Magnetics Society Distinguished Lecturer in 2015. The talk titled “Magnetic Nanowires: Revolutionizing Hard Drives, Random Access Memory (RAM), and Cancer Treatment,” delivered at KAUST resulted in a subsequent grant from the institution. The proposed project is a collaboration on several levels. Besides drawing on the labs that the individual investigators lead in their respective institutions, they will also rely on other facilities on the University campus (Minnesota Nanofabrication Center, Characterization Facility, and Minnesota Supercomputer Institute) and the expertise of researchers attached to these facilities.

The goals for the project are twofold, and combine science with outreach. Firstly, the undertaking will be a bold step towards resolving the challenges of data analysis and storage. Secondly, the project will include an educational aspect specifically targeted at women. Dr. Stadler will have the opportunity to reach out to students in Saudi women’s colleges and discuss her areas of interest with them. With the project scheduled to be completed over three years, and Dr. Stadler anticipates being at KAUST during years 1 and 3 of the project. So, she will have multiple opportunities to engage with local women scientists in training.

Prof. Stadler as Scientist and Teacher

As faculty in the Department of Electrical and Computer Engineering, Prof. Stadler has been with the University of Minnesota for almost 20 years. Her areas of expertise include magnetic nanowire arrays for high density RAM, nanowire RFID tags for cells, and integrated photonics. For the collaborative project with KAUST, she will draw on her expertise in nano-imprinting for long range order in aluminum oxide templates, and in design and synthesis of magnetic nanowires.

Prof. Stadler also has a significant trail of experience leading and conducting educational outreach activities and lectures to diverse audiences ranging from school students to graduate students and scholars in the discipline.

She has worked energetically to engage school children in science. She has led week-long summer camps for 10 years, designed for children between the ages of 8 and 15 teaching them the basics of circuits theory or electrochemistry. For example, camps included “Circuits are a Snap” and “Electric Ladies Week,” with the latter being all-girls camps. Other activities by Prof. Stadler include science demos at various venues, a nanotechnology open house attended by 450 students from across Minnesota, and helping High Tech Kids and high school robotics teams plan two statewide Kick-Offs for FIRST Technical Challenge.

Her service engagements have included serving as the faculty mentor for Society of Women Engineers (SWE) from 2005 to 2015. As a scientist, and engineer, Prof. Stadler has contributed her expertise in multiple ways to the IEEE Magnetics Society and the Materials Research Society. In 2015, she was invited to be a Distinguished Lecturer for the IEEE. In 2012 and 2013, Prof. Stadler was invited to give lectures at the IEEE Magnetics Summer Schools in Chennai, India and Assissi Italy, respectively. Impressed with the immense value of hosting such a school, she proposed and successfully won the bid to have the 2015 IEEE Magnetic Summer School hosted at the University of Minnesota in which IEEE funded 80 international students to come to Minnesota and learn about magnetics from global experts.

These diverse yet similar experiences will be resources for Prof. Stadler as she addresses the educational aspect of the proposed collaboration between the University and KAUST. While the project investigators and co-investigators will be devoting a significant part of their time to their project responsibilities, they are also looking forward to training at least five students over the span of three years. As part of their training, they will learn the latest micro and nanofabrication methods, and the use of equipment to carry out the fabrication processes. Another critical aspect of the knowledge exchange is the planned student exchange program between the University and KAUST.

The goal is to develop students into professionals in the discipline who learn from exposure to experts, other researchers, and differing work environments.

KAUST currently has a Visiting Student Research Program that the investigators hope to harness to recruit students from the University of Minnesota. Prof. Stadler also hopes to encourage students to attend training and learning opportunities such as the IEEE Magnetics Summer School, and lectures and demonstrations offered by the project’s lead scientists at both institutions.

Extending the educational and outreach aspects of this unique research opportunity, the team will also be offering short courses for female students in science and engineering while in Saudi Arabia. While these courses themselves will be hosted at KAUST, attendees will be from other Saudi institutions such as KAU Jeddah.

The collaboration with KAUST is obviously an exciting opportunity for Prof. Stadler and the Dept. of Electrical and Computer Engineering. We are hoping that this technical and educational collaboration will lead to advancements in the area of novel memory devices, and attract more students, especially women students to lead in the invention of new devices and technologies.

For more on Prof. Stadler’s research and accomplishments, click here

For more on Prof. Stadler’s Taylor Award for Distinguished Service, click here.


ASPLOS 2017 Best Paper Award For Hari Cherupalli And Prof. John Sartori

Determining Application-specific Peak Power and Energy Requirements for Ultra-low-power Processors,” authored by doctoral student Hari Cherupalli and Prof. John Sartori (besides authors from University of Illinois, Urbana-Champaign) has received the Best Paper Award at ASPLOS 2017. ASPLOS (ACM International Conference on Architectural Support for Programming Languages and Operating Systems) is a premier conference addressing “multidisciplinary systems research spanning computer architecture and hardware, programming languages and compilers, operating systems and networking, as well as applications and user interfaces.”

The award winning paper addresses the challenges presented by the inability of conventional techniques to accurately bound the power and energy requirements of specific applications in IoT, wearable devices, implantable devices, and others. The paper presents a solution that uses an automated technique that performs a hardware-software co-analysis of the application and the ultra-low-power processor in an embedded system to determine its specific peak power and energy requirements.


Prof. Gopinath Awarded 2017 Microwave Application Award by IEEE MTT-S

Prof. Anand Gopinath has been awarded the 2017 Microwave Application Award of the IEEE Microwave Theory and Techniques Society (MTT-S) for his contributions to the analysis of microstrip lines and their discontinuities.

Microstrip lines are widely used in high frequency circuits and the generic form is a printed line on a dielectric substrate with a ground plane. This citation recognizes the early vectorial solutions of wave propagation in these lines and also the calculation of phase shift through different types of discontinuities.

Dr. Gopinath has also published papers on microstrip losses and resonators, and in the microwave active circuits area. He has also contributed novel components for photonic integrated circuits, and more recently to the area of RF coils in Magnetic Resonant Imaging systems.

Prof. Gopinath earned his doctoral degree in electrical engineering from the University of Sheffield (UK) in 1965. His research areas include MRI systems, RF/microwave applications, analog RF/microwave circuits, metamaterials, photonic systems and devices, integrated and nano optics, and optoelectronics. He has previously been honored as Fellow of IET (London, 1982), IEEE (1990), and OSA (2002).

The Microwave Application Award was instituted to recognize an individual for an outstanding application of microwave theory and techniques such as the creation of a new device, component or technique, or novel use of a device or component.

The award will be conferred at the annual Society Awards Banquet scheduled for June 2017 at the International Microwave Symposium to be held in Honolulu, Hawaii.



Prof. Beth Stadler Receives 2017 Taylor Award for Distinguished Service

Prof. Bethanie Stadler is a recipient of the 2017 Taylor Award for Distinguished Service. The award is in recognition of her services to the magnetics and materials research communities, and her service to the department, the University, and the surrounding community.

The George W. Taylor Awards are endowed within the College of Science and Engineering in memory of George W. Taylor, a 1934 graduate of the department of Mechanical Engineering. The Service award is for a faculty member who has performed exemplary service within the University as well as in a professional capacity to outside public or governmental organizations.

Stadler’s record of service has included leadership roles within ECE, professional societies such as IEEE Magnetics Society and Materials Research Society, science outreach to the surrounding community through science summer camps, and service contributions to the University in roles such as member of the Senate Research Committee, and the CSE Consultative Committee.

At the departmental level, Prof. Stadler has chaired or co-led several key committees including the Graduate Committee, the ECE Summer REU and RET Programs, the ECE Consultative Committee, and the ECE Faculty Recruiting Committee. She also served as the faculty mentor for Society of Women Engineers (SWE) from 2005 to 2015. Reaching beyond the department, she has worked energetically to engage school children in science. She has led week-long summer camps for 10 years, designed for children between the ages of 8 and 15 teaching them the basics of circuits theory. The camps are called Circuits are a Snap and Electric Ladies Week, with the latter being an all-girls camp. Other activities by Prof. Stadler include science demos at various venues, a nanotechnology open house attended by 450 students from across Minnesota, and the statewide Kick-Off for FIRST Technical Challenge.

As a scientist, engineer, and teacher, Prof. Stadler has contributed her expertise in multiple ways to the IEEE Magnetics Society and the Materials Research Society. She was invited to be a Distinguished Lecturer for the IEEE in 2015, an honor and a significant commitment of time as Distinguished Lecturers are required to give between 20 to 40 lectures over the course of a year. She accepted the role and gave 59 lectures in 15 countries including Romania, Russia, Turkey, and Saudi Arabia. Stemming from her lecture in Saudi Arabia, Prof. Stadler has received a grant from King Abdullah University of Science and Technology. As part of the grant project, she will be travelling to the country for research, and outreach to women students of science in colleges across Saudi Arabia.

Prof. Stadler’s invited lectures at the IEEE Magnetics Summer School in Chennai, India and Assissi in Italy were extremely well received. Impressed with the immense value of hosting such a school, she proposed and successfully won the bid to have the 2015 IEEE Magnetic Summer School hosted at the University of Minnesota. The feedback on the school was overwhelmingly positive. But Prof. Stadler extended her engagement with the summer school further by writing the first IEEE Magnetic Summer School handbook drawing on not only her own experience leading one, but also on the experiences of chairs of previous such schools. The handbook was used by the 2016 host, Tohoku University in Japan, and is being used by the 2017 host, Universidad Internacional Menéndez Pelayo in Spain.

As an engaged volunteer of the Materials Research Society, Prof. Stadler established and directed the Undergraduate Materials Research Initiative in the late 1990s. A successful program, it was designed to encourage undergraduates to submit proposals to receive funding for research and travel to MRS meetings. 40 grants were awarded every year by the MRS while the program was in effect. She has also served the MRS in a variety of leadership roles and as secretary of the society in 2008, she took on the task to update the volunteer manual. She currently serves on the Program Development Subcommittee (PDSC), and will serve as Chair of the PDSC starting 2018.

Stadler is also the recipient of the Outstanding Mentor Award for the President’s Distinguished Faculty Mentor Program for Underrepresented Students (2011, and 2013), and a University of Minnesota McKnight Presidential Fellow (2006 – 2009) among several other awards.

The George W. Taylor Award was established in 1982. Besides Stadler, other ECE professors who have received this award include Stephen Campbell, James Leger, Douglas Ernie, Larry Kinney, and K.S.P. Kumar.

Prof. Mehmet Akçakaya Wins NSF CAREER Award for “Geometric Techniques for Big Data Medical Imaging”

Prof. Mehmet Akçakaya has been awarded the CAREER award by the National Science Foundation’s Faculty Early Career Development (CAREER) Program. This is one of the most prestigious awards instituted by the NSF to recognize and support faculty early in their careers who show the potential to “serve as academic role models in research and education and to lead advances in the mission of their department or organization.” The CAREER award ranges from $400,000 to $500,000 (depending on the research area) and is disbursed over a 5-year period.

The field of medical imaging has benefited from advances in signal and image processing, such as better data acquisition, superior reconstruction, and improved analysis of massive amounts of imaging data. However, with improving resolution and the push for comprehensive diagnosis, medical imaging faces new challenges such as larger data sizes, longer scan durations, and susceptibility to artifacts.

Mehmet’s CAREER award winning project seeks to address these challenges. It develops a multi-disciplinary framework to provide theoretical, algorithmic and application developments based on geometric methods to characterize the limits, and to improve the state of medical imaging reconstruction and analysis. His research uses geometric packing and covering techniques to theoretically characterize the performance of learning algorithms, phase retrieval for low-dimensional models, and optimization strategies for a class of parameter estimation problems in imaging. Algorithmic developments for each of these problems will complement the theoretical work, and will be applied to tackle existing medical imaging problems. These applications bear significant potential for translational impact within the US healthcare system, including improved diagnosis and throughput.

Prof. Akçakaya plans to integrate his research into the graduate and undergraduate curriculum, and expand the research process and outcomes to include the local community through outreach to K-12 students.

Mehmet earned his doctoral degree in 2010 from Harvard University (School of Engineering and Applied Sciences). He was a postdoctoral fellow at Beth Israel Deaconess Medical Center (BIDMC) from 2010 to 2012, and was an instructor with Harvard Medical School (BIDMC) from 2012 to 2015. He joined the University of Minnesota in 2015  as a faculty member with the Department of Electrical and Computer Engineering. He is also affiliated with the University’s Center for Magnetic Resonance Research. His research interests include biomedical image processing, big data signal processing, and magnetic resonance imaging. He has over 35 journal papers, and 11 approved/pending patents. He also holds an R00 award from the National Institutes of Health.

Flipping a magnetic memory cell with a light pulse

Scientists at the University of Minnesota have created a magnetic tunnel junction (MTJ) that can be switched by a pulse of light lasting one trillionth of a second, setting a speed record. The magnetic tunnel junction is a device critical to information technology with the termination of Moore’s law, a principle that has ruled the microelectronics industry for five decades.

This advancement holds promise for the development of new, optically controlled, ultrafast magnetic devices collectively called spintronics (electronics that combine optical and magnetic nanotechnologies). These devices could lead to innovations in the storage, processing, and communication of information in the coming decade. An example of such innovation would be the development of a system that like the human brain, can both store and analyze a large amount of data simultaneously.

The details of the device and the tests conducted on it are reported in the paper “All-Optical Switching of Magnetic Tunnel Junctions with Single Subpicosecond Laser Pulses,” published in Physical Review Applied (volume 7, issue 3).

For Prof. Mo Li, one of the lead scientists and associate professor in ECE, the outcome holds exciting prospects. “Our result establishes a new means of communication between fiber optics and magnetic devices. While fiber optics afford ultra-high data rate, magnetic devices can store data in a non-volatile way with high density.”

Typically, the MTJ has a sandwich-like structure comprising two layers of magnetic materials with an insulating layer, called barrier, in the middle. Information is written on the magnetic material by reversing the magnetization of one of the layers. This reversing process often involves spiral motion in the spinning electrons, called spin processing. However, there is a limitation on how fast the spin processing can be; the brakes are applied at roughly 1.6GHz, a current speed record that is much slower than silicon transistors. To enable faster writing speeds, the limitations on speed have to be overcome.

With the invention of a new MTJ by scientists at the University’s Department of Electrical and Computer Engineering, there is now a way to speed up things. Inspired by the 2007 discovery by Dutch and Japanese scientists that the magnetization of an alloy of gadolinium (Gd), a rare earth element, iron (Fe), and cobalt (Co) could be switched using light pulses, our scientists used the alloy to replace the upper magnetic layer of a conventional MTJ. Another modification they made to the device was to use a transparent electrical material called indium tin oxide for the electrode to allow light to pass through it. These layers are stacked into a pillar with a diameter of 10µm, which is only one tenth the diameter of a typical human hair.

To test, scientists sent laser pulses to the modified device using a low-cost laser based on optical fibers that emits ultrashort pulses of infrared light. The pulses are sent one in every microsecond (a microsecond is one millionth of a second), but each pulse is shorter than one trillionth of a second. Every time a pulse hit the MTJ pillar, the scientists observed a jump in the voltage on the device. The change in voltage confirms that the resistance of the MTJ sandwich changes each time the magnetization of the GdFeCo layer is switched. Because each laser pulse lasts less than 1 picosecond (a millionth of a microsecond), the device is capable of receiving data at a rate of 1 terabit per second!

According to C-SPIN director and ECE faculty, Prof. Jian-Ping Wang, also a lead scientist on the project, “The results offer a path towards a new category of optical spintronic devices that have the potential to address bandwidth limit and scaling challenges for future intelligent systems. These systems could use spin devices as neurons and synapses to perform computing and storage functions just like the brain, while using light to communicate the information.”

The ultimate goal for this research team is to shrink the size of the MTJ to less than 100 nanometers and reduce the required optical energy. To this end, the team is continuing its research, and is currently engaged in optimizing the material and structure of the device, and working on integrating it with nanophotonics.

In addition to Prof. Mo Li, and Prof. Jian-Ping Wang, postdoctoral associate Dr. Junyang Chen, and graduate student Li He, (both of whom made equal contributions to the work), are the leading authors of the paper.

This work was supported by C-SPIN, one of six centers of STARnet, a Semiconductor Research Corporation program, sponsored by MARCO and DARPA.

*Photo credit: Junyang Chen (an author of the paper)