Riemannian Geometric Computing: Applications in Imaging, Activity Modeling, and Mobile Health

Many physical phenomenon — such as motion, shape, and light — when observed using traditional visual sensors, as well as novel emerging sensors such as depth cameras, orientation sensors, and smart personal devices, result in complex, high-dimensional spatiotemporal signatures that are difficult to analyze. The sources of difficulty are many: high data throughput, non-trivial transformations required for inference, physical variabilities such as temporal re-parametrization and sensor placement, and the non-Euclidean nature of feature spaces due to physical constraints on environments.

Over the past decade, many of these constraints have been found to be expressible in the language of Riemannian geometry. We will start with presenting several motivating examples from imaging, signal and sensor processing, where Riemannian computing plays an important role. Along the way we will present a brief overview of how one can extend classical multi-variate statistics, signal approximation theory, etc. to develop novel frameworks for characterizing visual (and non-visual) phenomenon. We will discuss Gauss-Markov processes as simple yet powerful models to describe the space of dynamical primitives in human movement analysis. We show how to use the Riemannian geometric properties of this primitive-space to devise effective inference algorithms, for applications in activity recognition and pattern discovery from long videos. We also consider geometrically meaningful representation of human movement as a product-space of non-Euclidean groups and function-spaces, and present algorithmic approaches for constructing statistical signal models on these spaces. We further outline the future potential of Riemannian geometric computing and the tools developed in this agenda for several impactful applications: including in physical activity based mobile-health systems.

Posted in Events | Comments Off on Riemannian Geometric Computing: Applications in Imaging, Activity Modeling, and Mobile Health

Toward Large Interposer-based Multi-core Systems

Silicon interposers are already being commercially used for the aggressive integration of multiple 3D memory stacks in high-performance systems. This provides significant amounts of memory capacity within the package with very high bandwidths and low energy-per-bit costs. In this talk, I will provide an overview of the underlying technologies, and then discuss some challenges in future interposer-based systems. I will first consider a large multi-core CPU with 3D memory, and explore how the full potential of the integrated memory may be squandered if the in-package interconnect architecture cannot keep up with the data rates provided by the multiple memory stacks. I will then discuss a potential approach to leverage the interposer to “disintegrate” the multi-core CPU into several smaller (cheaper) chips while addressing the performance challenges that arise from fragmenting the multi-core into many more pieces. I will then conclude with a discussion of the many open research topics related to this approach, which will hopefully provide fertile ground for future research efforts and projects.

Event sponsored by the ACM Distinguished Speaker Program

Posted in Events | Comments Off on Toward Large Interposer-based Multi-core Systems

Planar External Cavity Single Frequency Low Noise Lasers

Planar external cavity (PLANEX) lasers combine high performance, similar to fiber/solid state lasers, with the small size, stability and high-reliability of diode lasers. Low phase/frequency noise and RIN enable distributed acoustic sensing and other fiber optic and free space sensing and metrology requirements. We will present PLC waveguide Bragg grating technology, PLANEX laser structure, cavity hybrid integration and performance, applications examples.

Posted in Events | Comments Off on Planar External Cavity Single Frequency Low Noise Lasers

Nature Materials publishes Prof. K. Banerjee’s study on electron/spin injection into atomically-flat materials

Nature Materials logo
Realizing good electrical contacts is critical to harnessing the full potential of emerging two-dimensional materials including graphene and various transition metal dichalcogenides for electronics, optoelectronics, and spintronics applications. The study examines the nature of such contacts and illuminates pathways to optimizing the injection of both charge and spin into atomically-thin semiconductors.

Members from ECE’s Nanoelectronics Research Lab, in collaboration with researchers at the Swiss Federal Institute of Technology-Lausanne (EPFL), have recently published a comprehensive study on the nature of charge and spin injection into atomically-thin two-dimensional (2D) semiconductors in the prestigious journal Nature Materials.

2D materials belonging to the graphene family, various transition metal dichalcogenides including molybdenum disulphide (MoS2) and tungsten diselenide (WSe2), as well as other 2D semiconductors such as monolayer Black Phosphorus have displayed unique potential in overcoming the limitations of conventional bulk materials (such as silicon and III-V semiconductors) for a number of exciting applications in electronics and optoelectronics, as well as spintronics and valleytronics. However, ensuring low-resistance or optimal contacts to such materials is the primary hindrance to using this technology.

Professor Banerjee’s group have made seminal contributions toward advancing the understanding of contacts to 2D materials and have also spearheaded the use of these materials for overcoming power dissipation and other fundamental challenges in nanoscale transistors, interconnects and sensors.

With an impact factor of 36.5, Nature Materials is the #1 ranked research journal in materials science covering all areas of materials including their nanoscale, biological and energy aspects.

Posted in News, Press Releases | Comments Off on Nature Materials publishes Prof. K. Banerjee’s study on electron/spin injection into atomically-flat materials

ME / ECE Distinguished Lecture: Engineering classes on a Massive Scale: The Good, the Bad, the Ugly

Bridging the theory-practice gap in engineering education is a well-known, hard nut to crack. This is particularly true in the controls curriculum, where deep mathematical theory must coexist alongside practical experiments and considerations. In this talk, we will discuss how this bridge-building can be approached both in a MOOC (Massive Open Online Course) setting, in flipped classrooms, and through the use of remote-access robotics testbeds. In particular, the recent MOOC, Control of Mobile Robots, has been used to flip classrooms in robotics and controls classes at the Georgia Institute of Technology and at other institutions. The students take the MOOC and come to class prepared to program robots. In this talk, we will discuss the outcomes of these educational experiments, show that control classes are potentially ideal candidates for flipped classes, yet present real challenges for meaningful learning experiences.

Posted in Events | Comments Off on ME / ECE Distinguished Lecture: Engineering classes on a Massive Scale: The Good, the Bad, the Ugly

Another Inconvenient Truth: Snails Are More Intelligent Than Us

For decades there has been a new CMOS technology node approximately every two years. Until recently, thanks to scaling, the key feature of every new technology node has been a 100% integration capacity and 40% performance improvement… free-of-charge. The International Technology Roadmap for Semiconductors (ITRS) has been architected in such a way that this improvement became a self-fulfilling prophecy of the roadmap itself. Everything else has been bent in the attempt to make scaling happen… forever.

For eons snails have built the cells of their shell according to the Fibonacci’s numbers: 0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, etc. – where each cell has a volume that is the sum of the volume of the previous two cells. Snails understand, however, that at a certain point in time growth must stop to prevent the collapse of the shell by making it too big and therefore fragile. When this point is reached, snails do stop adding larger cells, and start improving the robustness of the shell.

Back to us: technology-wise, scaling has rapidly exhausted the resources of CMOS technology, which, by now, struggles to deliver any further improvement. Economy-wise, Dr. Gordon Moore once observed:

“what we end up doing is really selling real estate. We’ve sold area on the silicon wafer for about a billion dollars an acre, that order of magnitude, as long as I’ve been in the industry“[1]

In order to stay afloat, the semiconductor industry would need to double the number of units it sells, from one technology node to the next. Not only is this clearly impossible, but it puts the semiconductor suppliers on a collision course with their customers, who are now looking for half the silicon area from one technology node to the next. Atoms don’t scale, and markets are finite.

As decimated vanguards approach the 32-nanometer node and start planning the jump to the 22-nanometer node, a number of fundamental challenges are emerging, both technical and financial, which force a thorough rethinking of how scaling has been done, and whether scaling continues to be the most appropriate solution to provide the world with the silicon content that it needs.

Like Al Gore’s premise on energy consumption and global warming, there is an inconvenient truth to be acknowledged in our industry: scaling is like fossil fuels – the cheapest and easiest way to go. Unfortunately, also like fossil fuels, it is not sustainable indefinitely. And it becomes more costly and inefficient every day. New avenues, which are available today, are worth exploring and must be undertaken. That is, unless snails are more intelligent than us…

In this keynote, Dr. Williams will describe the problems with scaling and a number of possible solutions, including the latest alternative paths and their relative merits.

Posted in Events | Comments Off on Another Inconvenient Truth: Snails Are More Intelligent Than Us

Bandits and Newsvendors: Joint Online Learning and Optimization in Wireless Networks

Algorithms for online learning and decision-making under uncertainty have become popular in recent years to improve the performance of wireless networks in unknown dynamic environments. I will give a brief overview of certain classic problem formulations such as multi-armed bandits (MAB) and newsvendor problems, talk about their applications to wireless networking, and present some recent results from my group’s research in this area. These include results for decentralized MAB, combinatorial MAB, contextual MAB, multi-period newsvendors, and optimized robotic network formation in unknown environments. This talk will cover joint work with students Dr. Yi Gai, Dr. Yanting Wu, Pranav Sarkar, Parisa Mansourifard, and Shangxing Wang, and faculty collaborators Rahul Jain, Tara Javidi, and Nora Ayanian.

Posted in Events | Comments Off on Bandits and Newsvendors: Joint Online Learning and Optimization in Wireless Networks

Professor Arthur Gossard receives the nation’s highest honor in science and technology – the National Medal of Technology and Innovation

photo of art gossard
Gossard, a research professor and professor emeritus of materials and of electrical and computer engineering at UC Santa Barbara, is among eight recipients named to receive the National Medal of Technology and Innovation and nine recipients of the National Medal of Science. All will be feted at a White House ceremony early next year.

Announced at the White House on December 22nd, President Obama said, “Science and technology are fundamental to solving some of our nation’s biggest challenges. The knowledge produced by these Americans today will carry our country’s legacy of innovation forward and continue to help countless others around the world. Their work is a testament to American ingenuity.”

The National Medal of Technology and Innovation was created by statute in 1980 and is administered for the White House by the U.S. Department of Commerce’s Patent and Trademark Office. The award recognizes those who have made lasting contributions to America’s competitiveness and quality of life and helped strengthen the nation’s technological workforce. A distinguished independent committee representing the private and public sectors submits recommendations to the president.

“I am thrilled and honored to join with our colleagues in congratulating Professor Gossard on his selection for the prestigious National Medal of Technology and Innovation,” said UC Santa Barbara Chancellor Henry T. Yang. “His creative approach to solving problems, combined with his wide-ranging expertise, relentless curiosity and lifelong passion for frontier-expanding research, has led to remarkable accomplishments that have profoundly influenced the current direction of semiconductor science and technology.

“Mobile phone communications, satellite reception, quantum computation and high-efficiency multi-junction solar cells for electricity generation are just some of the exciting fields that exemplify the rich consequences of his work,” Yang continued. “We are so very proud to see Professor Gossard’s achievements and contributions, especially his pioneering development of molecular-beam epitaxy, recognized in this meaningful way.”

Noted Rod Alferness, dean of the College of Engineering at UCSB, “Professor Gossard’s work in the area of materials growth is at the foundation of ground-breaking scientific and technological advances in semiconductor molecular layered materials. He and colleagues have leveraged this work to make fundamentally new optoelectronic devices, including the lasers and high-speed electronics that make the global Internet possible. The application of his discoveries and inventions has profoundly touched the daily lives of people worldwide.”

“I am honored to join the group of other scientists, engineers and technologists who have previously received this award,” Gossard said. “I want to thank my family, teachers and colleagues for their huge contributions. And I am pleased by the recognition that the award bring to UC and especially to UCSB.”

Posted in Awards, News | Comments Off on Professor Arthur Gossard receives the nation’s highest honor in science and technology – the National Medal of Technology and Innovation

ECE Professors John Bowers and Umesh Mishra elected to the 2015 National Academy of Inventors (NAI)

photo of John Bowers and Umesh Mishra Four UC Santa Barbara engineers have been elected to the National Academy of Inventors (NAI) for 2015. Recognized for their “highly prolific spirit of invention,” ECE Professors John Bowers & Umesh Mishra and Materials and Chemistry & Biochemistry Professors Craig Hawker & Galen Stucky are among the newest fellows elected by the organization.

They join 164 other new NAI members for 2015, bringing the total of NAI fellows to 582, representing more than 190 research universities and governmental and non-profit research institutions.

“Each of these prestigious members of our faculty have made discoveries and then translated them into applications that change the world, from energy efficiency in electronics, to innovative polymers, to life-saving biomedical technology,” commented Rod Alferness, dean of the UCSB College of Engineering. “Society is benefiting from their intellectual contributions right now, and their work propels us into a bright future. We are tremendously proud of the recognition by NAI.”

ECE Professor John Bowers
An expert in photonics and optoelectronics, electrical and computer engineering professor John Bowers’s research focuses on the use of light to transmit data. By integrating electronic and photonic elements on the same silicon-based chip, the next generations of computers and telecommunications devices will be able to receive and transmit data at much faster speeds and with a fraction of the energy that is being used today.

Bowers is the founding director of the UCSB Institute for Energy Efficiency and a cofounder of the campus’s Technology Management Program, as well as the West Coast lead for the federally funded American Institute for Manufacturing of Photonics. A veteran of industry who worked at Bell Laboratories and Honeywell before joining UCSB in 1987, Bowers has published 466 journal papers, received 54 patents and consults with numerous photonics manufacturing companies.

“It is very gratifying when new products or new companies come out of good research,” Bowers said of the “creative research” required to bring forth advanced technologies and bring them to the market.

Bowers is a member of the National Academy of Engineering, a fellow of the Institute of Electrical and Electronics Engineers, Optical Society of America (OSA) and the American Physical Society, and a recipient of the OSA Holonyak Prize.

ECE Professor Umesh Mishra
A whopping $40 billion in unused energy is wasted in the United States annually, and it’s not coming from the more obvious places in our energy infrastructure. Rather, the energy dissipation happens at the point of conversion, with the adaptors in our various devices changing the voltage that arrives through power outlets to be compatible with the smaller requirements of our machines, and losing the rest as heat.

Electrical and computer engineering professor Umesh Mishra has made it his mission to put an end to that waste of energy and money, and in doing so, help to update the country’s outdated and inefficient energy infrastructure. His research expertise is in gallium nitride (GaN) electronics, utilizing the fine control offered by the wide-bandgap semiconductor material over the flow of electrons, enabling more efficient power distribution in various industrial and commercial systems, as well as opening the way to better integration of renewable energy sources.

“The impact of gallium nitride-based electronics is to radically improve the efficiency for radio-frequency power generation used in wireless base stations and also all forms of power conversion including data servers, solar inverters and electric and hybrid car motor drives,” said Mishra, who is “honored” to be inducted into NAI. “This is an important step in the journey toward ultra-low wasted energy in these functions, which reduces cost, mitigates environmental impact and takes the shackles off system design while creating jobs.”

Mishra, who joined UCSB in 1990, is a member of the campus’s Solid State Lighting & Energy Electronics Center and holds the Donald W. Whittier Chair in Electrical Engineering. He is also leading research efforts as part of PowerAmerica, a federally funded national research and manufacturing consortium established to accelerate research and development of GaN and other wide-bandgap semiconductor technologies.

Posted in Awards, News | Comments Off on ECE Professors John Bowers and Umesh Mishra elected to the 2015 National Academy of Inventors (NAI)

SCL Lab alumni Han, Saxena & Melkote awarded the 2015 IEEE SPS Young Author Best Paper Award

photos of the awardees Signal Compression Lab (SCL) alumni Jingning Han, Ankur Saxena, and Vinay Melkote, awarded the 2015 IEEE Signal Processing Society Young Author Best Paper Award

They were awarded for their journal paper “Jointly Optimized Spatial Prediction and Block Transform for Video and Image Coding”. The paper was co-authored with their Signal Compression Lab (SCL) advisor Professor Ken Rose.

The award will be given during the 2016 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP) in Shanghai, China.

  • Han graduated with a Ph.D. in 2012 and currently works at Google
  • Saxena graduated with Ph.D. in 2008 and currently works at Samsung
  • Melkote graduated with a Ph.D. in 2010 and currently works at Xerox
Posted in News, Student News | Comments Off on SCL Lab alumni Han, Saxena & Melkote awarded the 2015 IEEE SPS Young Author Best Paper Award