EE Student Information

Seminar / Colloquium

SystemX Seminar: Robots that Work Together, Robots that Play Together

Topic: 
Robots that Work Together, Robots that Play Together
Abstract / Description: 

For robots to effectively operate in our world, they must master the skills of dynamic interaction. Autonomous cars must safely negotiate their trajectories with other vehicles and pedestrians as they drive to their destinations. UAVs must avoid collisions with other aircraft, as well as dynamic obstacles on the ground. Disaster response robots must coordinate to explore and map new disaster sites. In this talk I will describe recent work in my lab using distributed optimization to obtain algorithms for robots to cooperate, and game theoretic methods to obtain algorithms for robots to compete. I will present an algorithm for fleets of autonomous cars to cooperatively track a large number of vehicles and pedestrians in a city, an algorithm for multiple robots to manipulate an object to a goal while avoiding collisions, and a distributed multi-robot SLAM algorithm, all derived using the same underlying distributed optimization framework. I will also discuss algorithms based on the theory of dynamic games, in which each actor has its own objective and constraints. I will describe examples in autonomous drone racing, car racing, and autonomous driving that use game theoretic principles to solve for Nash equilibrium trajectories in real-time, in a receding horizon fashion. Throughout the talk, I will show results from hardware experiments with ground robots, autonomous cars, and quadrotor UAVs collaborating and competing in the scenarios above.

Date and Time: 
Thursday, October 28, 2021 - 5:30pm
Venue: 
Huang 18

SystemX BONUS Seminar: New consumer use cases are shaping the display architectures of tomorrow’s mixed reality headsets and smart glasses

Topic: 
New consumer use cases are shaping the display architectures of tomorrow’s mixed reality headsets and smart glasses
Abstract / Description: 

For the past decade, display and sensor hardware developments for mixed reality and smart glasses were merely a shot in the dark, providing enough display immersion and visual comfort for developers to build up apps, especially for the enterprise field. On the sensor side, emphasis was put on 6DOF head tracking and spatial mapping, gesture sensing and later eye tracking. Today, as universal use cases for consumer emerge such as co-presence, digital twin and remote conferencing, new requirements are expressed in the product requirement documents (PRD) to enable such experiences, both on the display and sensing side. It is not only a race to smaller form factor and light weight devices for large field of view (FOV) and lower power, but the requirements are also on additional display and sensing features specifically tuned to implement such new universal use cases. Broad acceptance of wearable displays especially in the consumer field is contingent on enabling these new display and sensing requirements in small form factors and low power.

Date and Time: 
Tuesday, October 26, 2021 - 2:30pm
Venue: 
Packard 202

SystemX Seminar: Flexible Electronics with Two-Dimensional and Layered Chalcogenide Compounds

Topic: 
Flexible Electronics with Two-Dimensional and Layered Chalcogenide Compounds
Abstract / Description: 

 

As of today, more than 20 billion devices, almost three times the number of people on earth, are connected to the internet. More than half of that are Internet-of-Things (IoT) devices and it is expected that flexible electronics will play a big role in developing new types of IoT sensor systems. Applications include environmental monitoring, food packaging, and biomedical applications like vital sign and disease detection on skin or inside of the human body. However, there are several material, device and integration challenges to solve before flexible IoT systems can become a reality. Most flexible substrates require low process temperature (typically <250 °C), which hinders the direct growth of high-quality semiconductors making the choice of materials limited. At the same time, typical device dimensions are on the micron-scale which leads to low performance and high power consumption. Here, I will show how layered and two-dimensional (2D) chalcogenide compounds can offer attractive solutions for the components needed in flexible electronics overcoming the previously mentioned limitations. I will present our recent work on flexible devices including transistors, sensors, solar cells and memory. In future, combining these devices, we can imagine self-powered flexible IoT systems enabled by low energy consumption and integrated energy harvesters.

Date and Time: 
Thursday, October 21, 2021 - 5:30pm
Venue: 
Huang 018 + Zoom

EST Seminar: Merging spintronics and quantum thermodynamics to harvest ambient thermal energy

Topic: 
Merging spintronics and quantum thermodynamics to harvest ambient thermal energy
Abstract / Description: 

Student organizer contact: Kirstin Schauble (kschaub@stanford.edu)


I will present a novel concept that blends spintronics and quantum thermodynamics to generate electricity. This concept is invoked to explain experimental observations of electrical generation across oxide1 and molecular spintronic devices that comprise paramagnetic centers sandwiched between electrodes with full transport spin polarization. The presence of so-called quantum resources2,3, leading to a source of work of quantum origin called ergotropy, appears to be manifest in sub-kBT spectral features, as well in an apparent signature of a phase transition of the spin fluctuations on the paramagnetic centers. I will discuss our present research tracks to better understand this spintronic quantum engine. General info may also be found at www.spinengine.tech.

References:

1. Katcko, K. et al. Spin-driven electrical power generation at room temperature. Communications Physics 2, 116 (2019).

2. Bresque, L. et al. Two-Qubit Engine Fueled by Entanglement and Local Measurements. Phys. Rev. Lett. 126, 120605 (2021).

3. Klatzow, J. et al. Experimental Demonstration of Quantum Effects in the Operation of Microscopic Heat Engines. Phys. Rev. Lett. 122, 110601 (2019).

Date and Time: 
Tuesday, October 19, 2021 - 10:30am

Probability Seminar: Probabilistic Littlewood–Offord anti-concentration results via model theory

Topic: 
Probabilistic Littlewood–Offord anti-concentration results via model theory
Abstract / Description: 

The classical Erdos–Littlewood–Offord theorem says that for any n nonzero vectors in R^d, a random signed sum concentrates on any point with probability at most O(n^{1/2}). Combining tools from probability theory, additive combinatorics, and model theory, we obtain an anti-concentration probability of n^{-1/2+o(1)} for any o-minimal set S in R^d — such as a hypersurface defined by a polynomial in x1,...,xn,exp(x1),...,exp(xn), or a restricted analytic function — not containing a line segment. We do this by showing such o-minimal sets have no higher-order additive structure, complementing work by Pila on lower-order additive structures developed to count rational and algebraic points of bounded height.

This is joint work with Jacob Fox and Matthew Kwan.

 

Date and Time: 
Monday, October 25, 2021 - 4:00pm
Venue: 
Sequoia 200

Probability Seminar: Cutoff for the asymmetric riffle shuffle

Topic: 
Cutoff for the asymmetric riffle shuffle
Abstract / Description: 

In the Gilbert–Shannon–Reeds shuffle, a deck of N cards is cut into two approximately equal parts which are riffled together uniformly at random. This Markov chain famously undergoes total variation cutoff after (3/2)*log_2(N) shuffles. We prove cutoff for asymmetric riffle shuffles in which the deck is cut into differently sized parts before riffling, confirming a conjecture of Lalley from 2000.

Date and Time: 
Monday, October 18, 2021 - 4:00pm
Venue: 
Sequoia 200

ISL Colloquium presents AI for clinical trials and clinical trials for AI

Topic: 
AI for clinical trials and clinical trials for AI
Abstract / Description: 

Note: this talk will be held in person in Packard 101, and will start at 4pm. The talk will be streamed on Zoom for those who cannot attend (registration link below).  Please join us for coffee starting at 3:30pm at the Grove outside Packard.

 

 

Date and Time: 
Thursday, October 21, 2021 - 4:00pm
Venue: 
Packard 101 + Zoom

ISL Colloquium presents Two Talks

Topic: 
Experimentation and Decision-Making in Two-Sided Marketplaces: The Impact of Interference / Simple Agent, Complex Environment: Efficient Reinforcement Learning with Agent States
Abstract / Description: 

Talk 1: Marketplace platforms use experiments (also known as "A/B tests") as a method for making data-driven decisions. When platforms consider introducing a new feature, they often first run an experiment to test the feature on a subset of users and then use this data to decide whether to launch the feature platform-wide. However, it is well documented that estimates of the treatment effect arising from these experiments may be biased, due to the presence of interference. In this talk, we survey a collection of recent results and insights we have developed on experimentation and decision-making in two-sided marketplaces. In particular, we study the bias that interference creates in both the treatment effect estimates as well as standard error estimates, and show how both types of biases affect the platform's ability to make decisions. We show that for a large class of interventions ("positive interventions"), these biases cause the platform to launch too often. Through simulations calibrated to real-world data, we show that in many settings the treatment effect bias impacts decision-making more than the standard error bias. Based on joint work with Ramesh Johari, Inessa Liskovich, Gabriel Weintraub, and Geng Zhao.


Talk 2: In this work, we design a simple reinforcement learning (RL) agent that implements an optimistic version of Q-learning and establish through regret analysis that this agent can operate with some level of competence in an arbitrarily complex environment. While we leverage concepts from the literature on provably efficient RL, we consider a general agent-environment interface and provide a novel agent design and analysis. This level of generality positions our results to inform the design of future agents for operation in complex real environments. We establish that, as time progresses, our agent performs competitively relative to policies that require longer times to evaluate. The time it takes to approach asymptotic performance is polynomial in the complexity of the agent's state representation and the time required to evaluate the best policy that the agent can represent. Notably, there is no dependence on the complexity of the environment. The ultimate per-period performance loss of the agent is bounded by a constant multiple of a measure of distortion introduced by the agent's state representation. This work is the first to establish that an algorithm approaches this asymptotic condition within a tractable time frame.

Date and Time: 
Thursday, October 14, 2021 - 4:00pm
Venue: 
Packard 101

Probability Seminar: Nonlinear large deviations: Mean-field and beyond

Topic: 
Nonlinear large deviations: Mean-field and beyond
Abstract / Description: 

Large deviations of nonlinear functions of adjacency matrices of sparse random graphs have gained considerable interest over the last decade. This includes popular examples like subgraph count, or the extreme eigenvalues. For the first half of the talk, we will discuss how the upper tail large deviation problem of subgraph count in a random regular graph can be reduced to a variational problem and how to solve such optimization. Next, we consider Erdos–Renyi graph $\mathcal{G}(n,p)$ in the regime of $p$ where largest eigenvalue is governed by localized statistics, such as high degree vertices. In particular, for $r \geq 1$ fixed, we will discuss the upper and lower tail probabilities of top $r$ eigenvalues jointly.

This talk is based on joint works with Bhaswar B. Bhattacharya, Amir Dembo, and Shirshendu Ganguly.

Date and Time: 
Monday, October 11, 2021 - 4:00pm
Venue: 
Sequoia 200

AP/P Colloquium: "On Ising’s Model of Ferromagnetism"

Topic: 
On Ising’s Model of Ferromagnetism
Abstract / Description: 

The 1D Ising model is a classical model of great historical significance for both classical and quantum statistical mechanics. Developments in the understanding of the Ising model have fundamentally impacted our knowledge of thermodynamics, critical phenomena, magnetism, conformal quantum field theories, particle physics, and fractionalization in many-body systems. Despite the theoretical impact of the Ising model there have been very few good 1D realizations of it in actual real material systems. However, it has been pointed out recently, that the material CoNb2O6, has a number of features that may make it the most ideal realization we have of the Ising model in one dimension. In this talk I will discuss the surprisingly complex physics resulting in this simple model and review the history of “Ising’s model” from both a scientific and human perspective. In the modern context I will review recent experiments by my group and others on CoNb2O6. In particular I will show how low frequency light in the THz range gives unique insight into the tremendous zoo of phenomena arising in this simple model system.

Date and Time: 
Tuesday, October 12, 2021 - 4:30pm

Pages

Applied Physics / Physics Colloquium

AP/P Colloquium: "On Ising’s Model of Ferromagnetism"

Topic: 
On Ising’s Model of Ferromagnetism
Abstract / Description: 

The 1D Ising model is a classical model of great historical significance for both classical and quantum statistical mechanics. Developments in the understanding of the Ising model have fundamentally impacted our knowledge of thermodynamics, critical phenomena, magnetism, conformal quantum field theories, particle physics, and fractionalization in many-body systems. Despite the theoretical impact of the Ising model there have been very few good 1D realizations of it in actual real material systems. However, it has been pointed out recently, that the material CoNb2O6, has a number of features that may make it the most ideal realization we have of the Ising model in one dimension. In this talk I will discuss the surprisingly complex physics resulting in this simple model and review the history of “Ising’s model” from both a scientific and human perspective. In the modern context I will review recent experiments by my group and others on CoNb2O6. In particular I will show how low frequency light in the THz range gives unique insight into the tremendous zoo of phenomena arising in this simple model system.

Date and Time: 
Tuesday, October 12, 2021 - 4:30pm

Applied Physics/Physics colloquium: Weaving together theoretical physics, machine learning and neuroscience: a tale of neurons, atoms and photons in the service of computation

Topic: 
Weaving together theoretical physics, machine learning and neuroscience: a tale of neurons, atoms and photons in the service of computation
Abstract / Description: 

We are witnessing an exciting interplay between physics, computation and neurobiology that spans in multiple directions. In one direction we can use the power of complex systems analysis, developed in theoretical physics and applied mathematics, to elucidate design principles governing how neural networks, both biological and artificial, can learn and function. In another direction, we can exploit novel physics to instantiate and analyze new kinds of quantum neuromorphic computers built using atomic spins and photons. We will give several vignettes in both directions, including: (1) deriving the detailed structure of the primate retina from first principles by developing optimal neural networks for processing natural movies, (2) using dynamic mean field theory to understand and optimize the training of deep neural networks used in machine learning, (3) understanding the geometry and dynamics of high dimensional optimization in the classical limit of a dissipative many-body quantum optimizer comprised of interacting photons.

References:
Y. Bahri, J. Kadmon, J. Pennington, S. Schoenholz, J. Sohl-Dickstein, and S. Ganguli, Statistical mechanics of deep learning, Annual Reviews of Condensed Matter Physics, 2020.
M. Advani, S. Lahiri and S. Ganguli, Statistical mechanics of complex neural systems and high dimensional data, Journal of Statistical Mechanics Theory and Experiment (2013), P03014.
S. Deny, J. Lindsey, S. Ganguli, S. Ocko, The emergence of multiple retinal cell types through efficient coding of natural movies, Neural Information Processing Systems (NeurIPS) 2018.
B. Poole, S. Lahiri, M. Raghu, J. Sohl-Dickstein, and S. Ganguli, Exponential expressivity in deep neural networks through transient chaos, Neural Information Processing Systems (NIPS) 2016.
J. Pennington, S. Schloenholz, and S. Ganguli, Resurrecting the sigmoid in deep learning through dynamical isometry: theory and practice, Neural Information Processing Systems (NIPS) 2017.
Y. Yamamoto, T. Leleu, S. Ganguli and H. Mabuchi, Coherent Ising Machines: quantum optics and neural network perspectives, Applied Physics Letters 2020.
B.P. Marsh, Y, Guo, R.M. Kroeze, S. Gopalakrishnan, S. Ganguli, J. Keeling, B.L. Lev, Enhancing associative memory recall and storage capacity using confocal cavity QED, Physical Review X, 2020.

Date and Time: 
Tuesday, October 5, 2021 - 4:30pm

Applied Physics/Physics colloquium present "Seeing to the Event Horizons of Supermassive Black Holes"

Topic: 
Seeing to the Event Horizons of Supermassive Black Holes
Abstract / Description: 

Supermassive black holes in the centers of galaxies power some of the brightest objects we see in the Universe; active galactic nuclei (AGN). Much remains unknown, however, about exactly how energy is released from the material falling in through the accretion disk, and from the black hole itself, to power these extreme systems, form a luminous X-ray emitting corona, and launch jets at almost the speed of light.

The X-rays emitted from the corona illuminate the material falling into the black hole and by measuring its reflection, we obtain a unique insight into the processes occurring just outside the event horizon. Most recently, measuring the echoes of X-ray flares emitted by the corona, we have been able to obtain the most detailed map of the structure of the inner accretion disk and corona, and have been able to detect the reverberation of the X-ray flare from material that should classically be hidden behind the shadow of the black hole.

The reverberation of X-ray flares is letting us see the corona evolve in real time and witness the effects of strong gravity and general relativity as the X-rays are bent around the black hole. This gives us important insight into the small-scale processes close to the event horizon that allow black holes to power these extreme objects and play their important feedback role in the formation of structure in the Universe.

Date and Time: 
Tuesday, September 28, 2021 - 4:30pm

Applied Physics 483 Optics & Electronics Seminar:Actively Tunable and Time-Modulated Flat Optics for Beam Steering, Multiplexing, and Polarization Conversion

Topic: 
Actively Tunable and Time-Modulated Flat Optics for Beam Steering, Multiplexing, and Polarization Conversion
Abstract / Description: 

Phase gradient metasurfaces are flat optical structures with potential to manipulate amplitude, phase, and polarization of electromagnetic waves using arrays of subwavelength nanoantennas. Currently most metasurfaces are 'static' and have functions that are fixed at the time of fabrication. By making antenna arrays tunable or reconfigurable in their phase, amplitude, and polarization response through incorporation of electro-optical effects, one can achieve spatiotemporal control of the phase gradient after fabrication. Time modulation can be either be 'quasi-static', where temporal variations are sufficiently slow that they do not change the scattered light frequency, or in a regime where the modulation rate is high enough to generate new frequencies. In this way, time modulation opens a four-dimensional active metasurface design space where control over the spectral content of scattered light, in addition to its spatial features, can extend light manipulation to encompass space-time photonic transitions. New materials are also adding new functions: the excitonic birefringence of the intriguing van der Waals semiconductor black phosphorus has enabled actively tunable spectrally broadband polarization conversion over nearly half the Poincaré sphere. Both linear to circular and cross-polarization conversion with voltage are possible, demonstrating dynamic access to polarization diversity.

Date and Time: 
Monday, October 18, 2021 - 4:15pm

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CS300 Seminar

#StanfordToo: A Conversation about Sexual Harassment in Our Academic Spaces

Topic: 
#StanfordToo: A Conversation about Sexual Harassment in Our Academic Spaces
Abstract / Description: 

Individuals of all genders invited to be a part of:
#StanfordToo: A Conversation about Sexual Harassment in Our Academic Spaces, where we will feature real stories of harassment at Stanford academic STEM in a conversation with Provost Drell, Dean Minor (SoM), and Dean Graham (SE3). We will have plenty of time for audience discussion on how we can take concrete action to dismantle this culture and actively work towards a more inclusive Stanford for everyone. While our emphasis is on STEM fields, we welcome and encourage participation from students, postdocs, staff, and faculty of all academic disciplines and backgrounds.

Date and Time: 
Friday, April 19, 2019 - 3:30pm
Venue: 
STLC 111

John G. Linvill Distinguished Seminar on Electronic Systems Technology

Topic: 
Internet of Things and Internet of Energy for Connecting at Any Time and Any Place
Abstract / Description: 

In this presentation, I would like to discuss with you how to establish a sustainable and smart society through the internet of energy for connecting at any time and any place. I suspect that you have heard the phrase, "Internet of Energy" less often. The meaning of this phrase is simple. Because of a ubiquitous energy transmission system, you do not need to worry about a shortage of electric power. One of the most important items for establishing a sustainable society is [...]


"Inaugural Linvill Distinguished Seminar on Electronic Systems Technology," EE News, July 2018

 

Date and Time: 
Monday, January 14, 2019 - 4:30pm
Venue: 
Hewlett 200

Special Seminar: Formal Methods meets Machine Learning: Explorations in Cyber-Physical Systems Design

Topic: 
Formal Methods meets Machine Learning: Explorations in Cyber-Physical Systems Design
Abstract / Description: 

Cyber-physical systems (CPS) are computational systems tightly integrated with physical processes. Examples include modern automobiles, fly-by-wire aircraft, software-controlled medical devices, robots, and many more. In recent times, these systems have exploded in complexity due to the growing amount of software and networking integrated into physical environments via real-time control loops, as well as the growing use of machine learning and artificial intelligence (AI) techniques. At the same time, these systems must be designed with strong verifiable guarantees.

In this talk, I will describe our research explorations at the intersection of machine learning and formal methods that address some of the challenges in CPS design. First, I will describe how machine learning techniques can be blended with formal methods to address challenges in specification, design, and verification of industrial CPS. In particular, I will discuss the use of formal inductive synthesis --- algorithmic synthesis from examples with formal guarantees — for CPS design. Next, I will discuss how formal methods can be used to improve the level of assurance in systems that rely heavily on machine learning, such as autonomous vehicles using deep learning for perception. Both theory and industrial case studies will be discussed, with a special focus on the automotive domain. I will conclude with a brief discussion of the major remaining challenges posed by the use of machine learning and AI in CPS.

Date and Time: 
Monday, December 4, 2017 - 4:00pm to Tuesday, December 5, 2017 - 3:55pm
Venue: 
Gates 463A

SpaceX's journey on the road to mars

Topic: 
SpaceX's journey on the road to mars
Abstract / Description: 

SSI will be hosting Gwynne Shotwell — President and COO of SpaceX — to discuss SpaceX's journey on the road to mars. The event will be on Wednesday Oct 11th from 7pm - 8pm in Dinkelspiel Auditorium. After the talk, there will be a Q&A session hosted by Steve Jurvetson from DFJ Venture Capital.

Claim your tickets now on eventbright

 

Date and Time: 
Wednesday, October 11, 2017 - 7:00pm to Thursday, October 12, 2017 - 6:55pm
Venue: 
Dinkelspiel Auditorium

CS Department Lecture Series (CS300)

Topic: 
Faculty speak about their research to new PhD students
Abstract / Description: 

Offered to incoming first-year PhD students in the Autumn quarter.

The seminar gives CS faculty the opportunity to speak about their research, which allows new CS PhD students the chance to learn about the professors and their research before permanently aligning.

4:30-5:15, Subhasish Mitra

5:15-6:00, Silvio Savarese

Date and Time: 
Wednesday, December 7, 2016 - 4:30pm to Thursday, December 8, 2016 - 5:55pm
Venue: 
200-305 Lane History Corner, Main Quad

CS Department Lecture Series (CS300)

Topic: 
Faculty speak about their research to new PhD students
Abstract / Description: 

Offered to incoming first-year PhD students in the Autumn quarter.

The seminar gives CS faculty the opportunity to speak about their research, which allows new CS PhD students the chance to learn about the professors and their research before permanently aligning.

4:30-5:15, Phil Levis

5:15-6:00, Ron Fedkiw

Date and Time: 
Monday, December 5, 2016 - 4:30pm to Tuesday, December 6, 2016 - 5:55pm
Venue: 
200-305 Lane History Corner, Main Quad

CS Department Lecture Series (CS300)

Topic: 
Faculty speak about their research to new PhD students
Abstract / Description: 

Offered to incoming first-year PhD students in the Autumn quarter.

The seminar gives CS faculty the opportunity to speak about their research, which allows new CS PhD students the chance to learn about the professors and their research before permanently aligning.

4:30-5:15, Dan Boneh

5:15-6:00, Aaron Sidford

Date and Time: 
Wednesday, November 30, 2016 - 4:30pm to Thursday, December 1, 2016 - 5:55pm
Venue: 
200-305 Lane History Corner, Main Quad

CS Department Lecture Series (CS300)

Topic: 
Faculty speak about their research to new PhD students
Abstract / Description: 

Offered to incoming first-year PhD students in the Autumn quarter.

The seminar gives CS faculty the opportunity to speak about their research, which allows new CS PhD students the chance to learn about the professors and their research before permanently aligning.

4:30-5:15, John Mitchell

5:15-6:00, James Zou

Date and Time: 
Monday, November 28, 2016 - 4:30pm to Tuesday, November 29, 2016 - 5:55pm
Venue: 
200-305 Lane History Corner, Main Quad

CS Department Lecture Series (CS300)

Topic: 
Faculty speak about their research to new PhD students
Abstract / Description: 

Offered to incoming first-year PhD students in the Autumn quarter.

The seminar gives CS faculty the opportunity to speak about their research, which allows new CS PhD students the chance to learn about the professors and their research before permanently aligning.

4:30-5:15, Emma Brunskill

5:15-6:00, Doug James

Date and Time: 
Wednesday, November 16, 2016 - 4:30pm to Thursday, November 17, 2016 - 5:55pm
Venue: 
200-305 Lane History Corner, Main Quad

CS Department Lecture Series (CS300)

Topic: 
Faculty speak about their research to new PhD students
Abstract / Description: 

Offered to incoming first-year PhD students in the Autumn quarter.

The seminar gives CS faculty the opportunity to speak about their research, which allows new CS PhD students the chance to learn about the professors and their research before permanently aligning.

4:30-5:15, James Landay

5:15-6:00, Dan Jurafsky

Date and Time: 
Monday, November 14, 2016 - 4:30pm to Tuesday, November 15, 2016 - 5:55pm
Venue: 
200-305 Lane History Corner, Main Quad

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EE380 Computer Systems Colloquium

SystemX presents "Quantum Computing – Where does the Hope meet the Hype?"

Topic: 
Quantum Computing – Where does the Hope meet the Hype?
Abstract / Description: 

Quantum computers exploit the bizarre features of quantum physics -- uncertainty, entanglement, and measurement -- to perform tasks that are impossible using conventional means, such as computing over ungodly amounts of data, and communicating via teleportation. I will describe the architecture of a quantum computer based on individual atomic clock qubits, suspended and isolated with electric fields, perfectly replicable with no idle errors, and individually addressed with laser beams. This leading physical representation of a quantum computer has allowed unmatched demonstrations of small algorithms and emulations of hard quantum problems with more than 50 quantum bits. While this system can solve some esoteric tasks that cannot be accomplished in conventional devices, it remains a great engineering challenge to build a quantum computer big enough to be generally useful for society. But the good news is that this is not a scientific challenge, as we know the technology needed and it's not quantum.

Date and Time: 
Thursday, October 8, 2020 - 4:30pm
Venue: 
Zoom ID: 920 2334 9868; +passcode

EE380 Computer Systems Colloquium presents "Coming Attractions: Death or Utopia in the Next Three Decades"

Topic: 
Coming Attractions: Death or Utopia in the Next Three Decades
Abstract / Description: 

Today the data suggests that we are near the beginning of a chaotic mess of global proportions. Things are fairly simple: a global pandemic with no tools to fight the virus. a global economy in disarray, climate change and other existential risks beginning to intrude into our daily lives, and a total lack of a plan as to what to do. On the other hand, we are at the pinnacle of human capabilities and have, if we choose to do so, the capability create a Utopian egalitarian world without conflict or want.

In this two hour program a group of experts will explore the future, focusing on 2030 and 2050. Where are we now? What is trending? What if anything can be done about it?


Sponsors: The invitational Asilomar Microcomputer Workshop is one of the iconic gatherings which supported the growth of computing. This is the first mini-conference which replaces the 46th Asilomar Microcomputer Workshop which was canceled due to the COVID-19 pandemic. www.amw.org.

Date and Time: 
Thursday, June 4, 2020 - 11:00am to Friday, June 5, 2020 - 10:55am
Venue: 
REGISTER to receive access

EE380 Computer Systems Colloquium presents "Rebooting the Internet"

Topic: 
Rebooting the Internet
Abstract / Description: 

"Build one and throw it out," so the adage goes. This talk explores the argument for systems architecture revision, including processors, operating systems, and networking--both as a general principle and the ways the Internet in particular is currently in need of a reboot. Assumptions, resources, and goals change with time and experience, and so too does our understanding of architectural principles. Through the eyes of the Internet and other examples, we review what we got right (one ring to rule them all, good enough rather than perfect), what we got wrong (7 layers, name resolution as afterthought), and what we only now are beginning to appreciate (layering and forwarding as one thing). Challenge cases are presented that can help drive this redesign, including single-packet exchanges and recursive layering, and an example given of one direction this approach can lead. Finally, we explore the challenges of evolution and transition to help us prepare for giving the Internet a well-deserved reset.

REMOTE URL SU-EE380-20200311

Date and Time: 
Wednesday, March 11, 2020 - 4:30pm
Venue: 
[remote only]

EE380 Computer Systems Colloquium presents "Data Analytics at the Exascale for Free Electron Lasers Lasers Project"

Topic: 
Data Analytics at the Exascale for Free Electron Lasers Lasers Project
Abstract / Description: 

The increase in velocity, volume, and complexity of the data generated by the upcoming Linac Coherent Light Source upgrade (LCLS-II) at the SLAC National Accelerator Laboratory presents a considerable challenge for data acquisition, data processing, and data management. These systems face formidable challenges due to the extremely high data throughput, hundreds of GB/s to multi-TB/s, generated by the detectors at the experimental facilities and to the intensive computational demand for data processing and scientific interpretation. The LCLS-II Data System is a fast, powerful, and flexible architecture that includes a feature extraction layer designed to reduce the data volumes by at least one order of magnitude while preserving the science content of the data. Innovative architectures are required to implement this reduction with a configurable approach that can adapt to the multiple science areas served by LCLS. In order to increase the likelihood of experiment success and improve the quality of recorded data, a real-time analysis framework provides visualization and graphically-configurable analysis of a selectable subset of the data on the timescale of seconds. A fast feedback layer offers dedicated processing resources to the running experiment in order to provide experimenters feedback about the quality of acquired data within minutes. We will present an overview of the LCLS-II Data System architecture with an emphasis on the Data Reduction Pipeline (DRP) and online monitoring framework.

Date and Time: 
Wednesday, March 4, 2020 - 4:30pm
Venue: 
Shriram 104

EE380 Computer Systems Colloquium presents "The Soul of a New Machine: Rethinking the Computer"

Topic: 
The Soul of a New Machine: Rethinking the Computer
Abstract / Description: 

While our software systems have become increasingly elastic, the physical substrate available to run that software (that is, the computer!) has remained stuck in a bygone era of PC architecture. Hyperscale infrastructure providers have long since figured this out, building machines that are fit to purpose -- but those advances have been denied to the mass market. In this talk, we will talk about our vision for a new, rack-scale, server-side machine -- and how we anticipate advances like open firmware, RISC-V, and Rust will play a central role in realizing that vision.

Date and Time: 
Wednesday, February 26, 2020 - 4:30pm
Venue: 
Shriram 104

EE380 Computer Systems Colloquium presents "fastai: A Layered API for Deep Learning"

Topic: 
fastai: A Layered API for Deep Learning
Abstract / Description: 


[speaker photo] Sylvain's research at fast.ai has focused on designing and improving techniques that allow models to train fast with limited resources. He has also been a core developer of the fastai library, including implementing the warping transformations, the preprocessing pipeline, much of fastai.text, and a lot more.
Prior to fastai, Sylvain was a Mathematics and Computer Science teacher in Paris for seven years. He taught CPGE, the 2-year French program that prepares students for graduate programs at France's top engineering schools (the "grandes écoles"). After relocating to the USA in 2015, Sylvain wrote ten textbooks covering the entire CPGE curriculum. Sylvain is an alumni from École Normale Supérieure (Paris, France) and has a Master's Degree in Mathematics from University Paris XI (Orsay, France). He lives in Brooklyn with his husband and two sons.fastai is a deep learning library which provides practitioners with high-level components that can quickly and easily provide state-of-the-art results in standard deep learning domains, and provides researchers with low-level components that can be mixed and matched to build new approaches. It aims to do both things without substantial compromises in ease of use, flexibility, or performance. This is possible thanks to a carefully layered architecture, which expresses common underlying patterns of many deep learning and data processing techniques in terms of decoupled abstractions. These abstractions can be expressed concisely and clearly by leveraging the dynamism of the underlying Python language and the flexibility of the PyTorch library. fastai includes: a new type dispatch system for Python along with a semantic type hierarchy for tensors; a GPU-optimized computer vision library which can be extended in pure Python; an optimizer which refactors out the common functionality of modern optimizers into two basic pieces, allowing optimization algorithms to be implemented in 4-5 lines of code; a novel 2-way callback system that can access any part of the data, model, or optimizer and change it at any point during training; a new data block API; and much more. We have used this library to successfully create a complete deep learning course, which we were able to write more quickly than using previous approaches, and the code was more clear. The library is already in wide use in research, industry, and teaching.

Date and Time: 
Wednesday, February 19, 2020 - 4:30pm
Venue: 
Shriram 104

EE380 Computer Systems Colloquium presents "Centaur Technology's Deep learning Coprocessor"

Topic: 
Centaur Technology's Deep learning Coprocessor
Abstract / Description: 

This talk will explore Centaur's microprocessor-design technology includes both a new high-performance x86 core AND the industry's FIRST integrated AI Coprocessor for x86 systems. The x86 microprocessor cores deliver high instructions/clock (IPC) for server-class applications and support the latest x86 extensions such as AVX 512 and new instructions for fast transfer of AI data. The AI Coprocessor is a clean-sheet processor designed to deliver high performance and efficiency on deep-learning applications, freeing up the x86 cores for general-purpose computing. Both the x86 and AI Coprocessor technologies have now been proven in silicon using a new scalable SoC platform with eight x86 cores and an AI Coprocessor able to compute 20 trillion AI operations/sec with 20 terabytes/sec memory bandwidth. This SoC architecture requires less than 195mm2 in TSMC 16nm and provides an extensible platform with 44 PCIe lanes and 4 channels of PC3200 DDR4.

Date and Time: 
Wednesday, February 12, 2020 - 4:30pm
Venue: 
Shriram 104

EE380 Computer Systems Colloquium presents "KUtrace 2020"

Topic: 
KUtrace 2020
Abstract / Description: 

Observation tools for understanding occasionally-slow performance in large-scale distributed transaction systems are not keeping up with the complexity of the environment. The same applies to large database systems, to real-time control systems in cars and airplanes, and to operating system design.

Extremely low-overhead tracing can reveal the true execution and non-execution (waiting) dynamics of such software, running in situ with live traffic. KUtrace is such a tool, based on small Linux kernel patches recording and timestamping every transition between kernel- and user-mode execution across all CPUs of a datacenter or vehicle computer. The resulting displays show exactly what each transaction is doing every nanosecond, and hence shows why unpredictable ones are slow, all with tracing overhead well under 1%. Recent additions to KUtrace also show interference between programs and show profiles within long execution stretches that have no transitions.

The net result is deep insight into the dynamics of complex software, leading to often-simple changes to improve performance.

Date and Time: 
Wednesday, February 5, 2020 - 4:30pm
Venue: 
Shriram 104

EE380 Computer Systems Colloquium presents "Computer Security: The Mess We're In, How We Got Here, and What to Do About It"

Topic: 
Computer Security: The Mess We're In, How We Got Here, and What to Do About It
Abstract / Description: 

There are dozens of companies selling products to solve your Identity and Access Management (IAM) problems. Why so many? Because IAM is really hard. But why is IAM so hard? I hope to convince you in this talk the reason is that our approach to IAM is fundamentally flawed. The talk includes my personal theory of how we got into this mess and a strategy for getting out of it.

Date and Time: 
Wednesday, January 29, 2020 - 4:30pm
Venue: 
Shriram 104

EE380 Computer Systems Colloquium presents "A Fight over the Law of Software APIs, and other war stories from the Electronic Frontier Foundation""

Topic: 
A Fight over the Law of Software APIs, and other war stories from the Electronic Frontier Foundation
Abstract / Description: 

Over the past four years, a federal appeals court has upended a basic assumption about software: that while software can be covered by copyright law, software interfaces cannot. The court ruled that Google's re-implementation of Java APIs infringed Oracle's Java copyrights. Now, the Supreme Court will weigh in. The Electronic Frontier Foundation has argued at each stage of the case that copyright in APIs threatens innovation, especially by smaller players. This is part of EFF's work promoting the freedom to tinker, innovate, and research, especially outside the walls of major corporations—work that has also included challenges to overbroad computer crime and "anti-circumvention" laws.

Date and Time: 
Wednesday, January 22, 2020 - 4:30pm
Venue: 
Shriram 104

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Ginzton Lab

SPRC & SOS Seminar: Trace Gas Flux Measurements in Artic Ecosystems – Current Applications and Future Perspectives

Topic: 
Trace Gas Flux Measurements in Artic Ecosystems – Current Applications and Future Perspectives
Abstract / Description: 

The exchanges of carbon dioxide (CO2) and methane (CH4) between arctic ecosystems and the atmosphere are sizeable and may if they change may alter the further development of climate warming. These fluxes take place between the atmospheric background of these trace gases and a very large reservoir of organic carbon stored in arctic soils and sediments. The stored carbon amounts to more than twice the current global atmospheric burden of CO2. Therefore, accurate measurements of the fluxes and how they vary temporally and spatially is key to understanding possible ecosystem impacts on the atmospheric mixing ratios and hence climate.
This presentation will detail the current state of the global CO2 and CH4 budget and review methods applied in quantifying the arctic trace gas flux components. The presentation will show new developments in the attempts to use UAV's to help improve spatial coverage of measured fluxes. The challenges in applying the laser techniques needed for the precise and fast trace gas measurements under true arctic conditions will be discussed.

Date and Time: 
Tuesday, May 4, 2021 - 11:00am to Wednesday, May 5, 2021 - 10:55am

OSA/SPIE present "Observing Ocean Health With A Global Network of Chemical and Biological Sensors on Robotic Platforms: Biogeochemical-Argo"

Topic: 
Observing Ocean Health With A Global Network of Chemical and Biological Sensors on Robotic Platforms: Biogeochemical-Argo
Abstract / Description: 

The ocean is under threat from a variety of processes driven by increasing atmospheric carbon dioxide such as ocean warming, changing winds and currents, decreasing pH and oxygen, and less ice cover at high latitudes. However, vast areas of the open ocean are sampled from research ships for chemical and biological properties only once per decade or less, with sampling occurring mainly in summer. Our ability to detect changes in ocean chemical and biological processes that may be occurring are greatly hindered by this undersampling. Robotic platforms carrying chemical and biological sensors that can monitor ocean metabolism, such as rates of oxygen production, nutrient uptake, accumulation of plankton biomass, and respiration, are required. The platforms and sensors must operate for the 5 to 10 year period between research vessel visits with no direct human intervention and little or no chance for sensor recalibration. Here, I'll describe the BGC-Argo network, which is being implemented to meet this mission. The BGC-Argo array is based on profiling floats that cycle through the upper 2 kilometers of the ocean every 10 days for 4 to 6 years. These floats carry optical sensors for oxygen, nitrate, chlorophyll, and particles, as well as electrochemical sensors for pH and physical sensors for temperature, pressure and salinity. The nitrate and pH sensors used in the array were developed at MBARI. With funding from NSF, NOAA, and NASA, we have deployed 200 floats in the Southern Ocean over the past 6 years. A recent research infrastructure grant from the NSF will extend the Southern Ocean array to the globe with 500 floats additional floats.

Date and Time: 
Tuesday, January 26, 2021 - 1:30pm

OSA/SPIE, SPRC and Ginzton Lab present "Next Generation Photonics"

Topic: 
Next Generation Photonics
Abstract / Description: 

Over the past few decades, silicon photonics has revolutionized photonic integrated circuits by leveraging the semiconductor CMOS manufacturing infrastructure for low cost, high performance devices and systems. However, key fundamental challenges of the field remain unsolved: packaging the devices with optical fibers and generating light on chip.

We developed a novel approach for fiber packaging based on fusing the fiber and chip together. Connecting a silicon photonic chip across long distances requires attaching optical fibers to the chip. In practice, the packaging of optical fibers to photonic devices is time consuming, lossy, and expensive. This process is usually done by gluing the fiber and chip together using optical adhesives. By fusion splicing the chip and fiber together we have demonstrated losses as low as 1dB for single fibers and 2.5dB for an array of four fibers.

Imagine a laser as thick as an atom that is compatible with silicon photonics. Silicon based materials are passive. Since silicon is an indirect band gap material it is a poor light emitter. To generate light on a silicon photonic integrated circuit, you need to integrate active materials, which are usually not compatible with CMOS, with the device. Two-dimensional materials are excellent candidates for light sources, modulators, and detectors; and they are compatible with CMOS electronic manufacturing in the back end. We recently demonstrated the first fully on-chip 2D laser. Due to their thickness and transfer process, we envision electronic-photonic devices with many optical layers, each with their own lasers, modulators, and detectors based on 2D materials. Our recent demonstration completes the set of active devices completely based on 2D materials.


Password: 017994

Date and Time: 
Wednesday, May 6, 2020 - 1:00pm to Thursday, May 7, 2020 - 12:55pm
Venue: 
Zoom ID: 991 2584 9377

OSA/SPIE with SPRC and Ginzton Lab present "Next Generation Photonics"

Topic: 
Next Generation Photonics
Abstract / Description: 

Over the past few decades, silicon photonics has revolutionized photonic integrated circuits by leveraging the semiconductor CMOS manufacturing infrastructure for low cost, high performance devices and systems. However, key fundamental challenges of the field remain unsolved: packaging the devices with optical fibers and generating light on chip.

We developed a novel approach for fiber packaging based on fusing the fiber and chip together. Connecting a silicon photonic chip across long distances requires attaching optical fibers to the chip. In practice, the packaging of optical fibers to photonic devices is time consuming, lossy, and expensive. This process is usually done by gluing the fiber and chip together using optical adhesives. By fusion splicing the chip and fiber together we have demonstrated losses as low as 1dB for single fibers and 2.5dB for an array of four fibers.

Imagine a laser as thick as an atom that is compatible with silicon photonics. Silicon based materials are passive. Since silicon is an indirect band gap material it is a poor light emitter. To generate light on a silicon photonic integrated circuit, you need to integrate active materials, which are usually not compatible with CMOS, with the device. Two-dimensional materials are excellent candidates for light sources, modulators, and detectors; and they are compatible with CMOS electronic manufacturing in the back end. We recently demonstrated the first fully on-chip 2D laser. Due to their thickness and transfer process, we envision electronic-photonic devices with many optical layers, each with their own lasers, modulators, and detectors based on 2D materials. Our recent demonstration completes the set of active devices completely based on 2D materials.

Date and Time: 
Monday, May 4, 2020 - 12:05pm
Venue: 
Zoom ID: 991 2584 9377 (contact organizers for password)

OSA/SPIE, SPRC and Ginzton Lab present "Applications of Precision Motion Control in the Optics and Photonics Industry"

Topic: 
Applications of Precision Motion Control in the Optics and Photonics Industry
Abstract / Description: 

Precision Automation has become a rapidly growing industry as manufacturers must develop ways to achieve ever-tightening tolerances. Likewise, research must push the envelope in order to maintain the increasingly advancing pace of technology. Aerotech has been providing assistance and solutions to researchers within academia and laboratories worldwide for 50 years and continues to empower students and technicians to complete and publish their research. In this seminar, we will discuss why automation and motion control is important as well as the various methods by which Aerotech has helped expand the boundaries of research in the field of optics and photonics. The topics we will cover in this session include:

  • What Precision Motion Control is and why it is important
  • How to choose the right set of motion control
  • How Aerotech has helped further research in:
    • Optics design and manufacturing
    • Light sources and beamlines
    • Optical positioning and ultra-fast spectroscopy
    • Fiber alignment
    • Laser Processing
    • Additive Manufacturing

After the presentation, a round-table discussion will be held during which we'd like to hear from you! Please bring with you any topics and - more importantly - any tough issues that you'd like to pose pertaining to automated motion control within your specific research field.

Date and Time: 
Tuesday, March 3, 2020 - 4:15pm
Venue: 
Spilker 232

OSA/SPIE present "Applications of Precision Motion Control in the Optics and Photonics Industry"

Topic: 
Applications of Precision Motion Control in the Optics and Photonics Industry
Abstract / Description: 

Refreshments at 4:00

Precision Automation has become a rapidly growing industry as manufacturers must develop ways to achieve ever-tightening tolerances. Likewise, research must push the envelope in order to maintain the increasingly advancing pace of technology. Aerotech has been providing assistance and solutions to researchers within academia and laboratories worldwide for 50 years and continues to empower students and technicians to complete and publish their research. In this seminar, we will discuss why automation and motion control is important as well as the various methods by which Aerotech has helped expand the boundaries of research in the field of optics and photonics. The topics we will cover in this session include:

  • What Precision Motion Control is and why it is important
  • How to choose the right set of motion control
  • How Aerotech has helped further research in:
    • Optics design and manufacturing
    • Light sources and beamlines
    • Optical positioning and ultra-fast spectroscopy
    • Fiber alignment
    • Laser Processing
    • Additive Manufacturing

After the presentation, a round-table discussion will be held during which we'd like to hear from you! Please bring with you any topics and - more importantly - any tough issues that you'd like to pose pertaining to automated motion control within your specific research field.

 

Date and Time: 
Wednesday, February 26, 2020 - 4:15pm
Venue: 
Spilker 232

OSA/SPIE, SPRC and Ginzton Lab present "Innovation in the Laser Industry"

Topic: 
Innovation in the Laser Industry
Abstract / Description: 
Spectra-Physics was a startup when Prof. Byer was a summer student in 1964.  By the time Alan Petersen and Jim Kafka joined in the early 1980s, the company had matured and aspired to be all things in lasers.  We will discuss the changes in the laser industry since that time and the role of innovation within the company to drive growth and broaden the product offerings from scientific lasers to industrial laser systems.
 
PLEASE RVP TO GUARANTEE A SPOT.
Date and Time: 
Monday, March 9, 2020 - 12:30pm
Venue: 
Y2E2 299

Q-Farm Quantum Seminar Series presents "Surprises from Time Crystals"

Topic: 
Surprises from Time Crystals
Abstract / Description: 

Time crystals are new states of matter that only exist in an out-of-equilibrium setting. I will review the state of this rapidly evolving field, focusing in particular on some of the remarkable properties of this phase, and the surprises coming out of its study. I will provide a detailed overview of existing experiments, with a view towards identifying the ingredients needed for an unambiguous observation of this phase in the future.

Date and Time: 
Wednesday, January 29, 2020 - 12:00pm to Thursday, January 30, 2020 - 11:55am
Venue: 
Hansen Physics & Astrophysics Building, 102/103

AP 483 Seminar Series presents "Photovoltaic Restoration of Sight in Retinal Degeneration"

Topic: 
Photovoltaic Restoration of Sight in Retinal Degeneration
Abstract / Description: 

Retinal degenerative diseases lead to blindness due to loss of the “image capturing” photoreceptors, while neurons in the “image-processing” inner retinal layers are relatively well-preserved. Information can be reintroduced into the visual system by photovoltaic subretinal implants, which convert incident light into electric current and stimulate the secondary retinal neurons.

 

To provide sufficient light intensity for photovoltaic stimulation while avoiding visual perception by remaining photoreceptors, images captured by a camera are projected onto the retina from augmented-reality glasses using pulsed near-infrared light. This design avoids the use of bulky electronics and wiring, thereby greatly reducing the surgical complexity and enabling scaling the number of photovoltaic pixels to thousands. Many features of the natural retinal signal processing are preserved in this approach, and spatial resolution matches the pixel pitch (so far 100 μm pixels in human patients, and 50 μm in rodents). For a broad acceptance of this technology by patients who lost central vision due to Age-Related Macular Degeneration, visual acuity should exceed 20/100, which requires pixels smaller than 25 μm. I will present a 3-dimensional electro-neural interface scalable to cellular dimensions and discuss the outlook and challenges for future developments.


 AP483 Optics and Electronics Seminar Series 2019-20 (Sponsored by Ginzton Laboratory, SPRC, Applied Physics, Physics, and HEPL).

Date and Time: 
Monday, February 24, 2020 - 4:15pm
Venue: 
Spilker 232

AP 483 Seminar Series presents "Taking the Humble FBG on a Voyage of Discovery from the Lab Bench to the Hospital and Beyond"

Topic: 
Taking the Humble FBG on a Voyage of Discovery from the Lab Bench to the Hospital and Beyond
Abstract / Description: 

Fiber Bragg gratings (FBGs) emerged almost magically in 1978. Since then, they have developed from being primarily of academic interest, to being one of the most versatile photonic components for both telecommunications and sensing. 

I was lucky enough to get introduced to photonics during the early years of discovery and experimentation with FBGs and ended up making FBG components for telecommunications. Jumping forward a few decades, I had moved away from telecommunications and had started to dabble with free space optical sensing. Then, during a chance meeting over a beer in Sydney, I was asked, rather naively, if it was possible to use optical fiber to monitor what goes on in the esophagus when we swallow. This set me off on an entirely new path and, pulling together some ideas from telecoms, and some basic mechanical engineering, my team ended up developing a range of sensors for monitoring pressure in the human digestive tract. 

Being able to detect swallowing disorders quickly led to monitoring in other regions of the gut, like the colon and small bowel, and, together with colleagues from Flinders Medical Center, we provided some details of the inner workings of the human gastrointestinal tract. Thus, the fiber optic catheter was born. This device kept me busy for almost 10 years, during which time we worked closely with clinical research groups to write a whole new chapter on how the gut works.

The next ‘Eureka’ moment came when we had to develop a temperature independent version of our sensor, initially for monitoring pressure beneath bandages. The very simple design that resulted worked well for sub-bandage measurements but has also become a key technology that has moved to applications in aerospace, pipeline monitoring, and mining.

When I started working in optics, I never thought I'd end up monitoring what makes your stomach growl when hungry, how air flows across an airplane wing, or detecting pressure transients in water pipes. 

During this talk I will explain how our basic transducers work and will then describe the applications they are now being applied to, demonstrating how the humble FBG has opened up the scope and reach of fiber-optic sensing.


 

AP483 Optics and Electronics Seminar Series 2019-20 (Sponsored by Ginzton Laboratory, SPRC, Applied Physics, Physics, and HEPL).

Date and Time: 
Monday, February 10, 2020 - 4:15pm
Venue: 
Spilker 232

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Information Systems Lab (ISL) Colloquium

ISL Colloquium presents AI for clinical trials and clinical trials for AI

Topic: 
AI for clinical trials and clinical trials for AI
Abstract / Description: 

Note: this talk will be held in person in Packard 101, and will start at 4pm. The talk will be streamed on Zoom for those who cannot attend (registration link below).  Please join us for coffee starting at 3:30pm at the Grove outside Packard.

 

 

Date and Time: 
Thursday, October 21, 2021 - 4:00pm
Venue: 
Packard 101 + Zoom

ISL Colloquium presents Two Talks

Topic: 
Experimentation and Decision-Making in Two-Sided Marketplaces: The Impact of Interference / Simple Agent, Complex Environment: Efficient Reinforcement Learning with Agent States
Abstract / Description: 

Talk 1: Marketplace platforms use experiments (also known as "A/B tests") as a method for making data-driven decisions. When platforms consider introducing a new feature, they often first run an experiment to test the feature on a subset of users and then use this data to decide whether to launch the feature platform-wide. However, it is well documented that estimates of the treatment effect arising from these experiments may be biased, due to the presence of interference. In this talk, we survey a collection of recent results and insights we have developed on experimentation and decision-making in two-sided marketplaces. In particular, we study the bias that interference creates in both the treatment effect estimates as well as standard error estimates, and show how both types of biases affect the platform's ability to make decisions. We show that for a large class of interventions ("positive interventions"), these biases cause the platform to launch too often. Through simulations calibrated to real-world data, we show that in many settings the treatment effect bias impacts decision-making more than the standard error bias. Based on joint work with Ramesh Johari, Inessa Liskovich, Gabriel Weintraub, and Geng Zhao.


Talk 2: In this work, we design a simple reinforcement learning (RL) agent that implements an optimistic version of Q-learning and establish through regret analysis that this agent can operate with some level of competence in an arbitrarily complex environment. While we leverage concepts from the literature on provably efficient RL, we consider a general agent-environment interface and provide a novel agent design and analysis. This level of generality positions our results to inform the design of future agents for operation in complex real environments. We establish that, as time progresses, our agent performs competitively relative to policies that require longer times to evaluate. The time it takes to approach asymptotic performance is polynomial in the complexity of the agent's state representation and the time required to evaluate the best policy that the agent can represent. Notably, there is no dependence on the complexity of the environment. The ultimate per-period performance loss of the agent is bounded by a constant multiple of a measure of distortion introduced by the agent's state representation. This work is the first to establish that an algorithm approaches this asymptotic condition within a tractable time frame.

Date and Time: 
Thursday, October 14, 2021 - 4:00pm
Venue: 
Packard 101

ISL Colloquium: KO codes: Inventing Non-linear Encoding and Decoding for Reliable Wireless Communication via Deep-learning

Topic: 
KO codes: Inventing Non-linear Encoding and Decoding for Reliable Wireless Communication via Deep-learning
Abstract / Description: 

Landmark codes underpin reliable physical layer communication, e.g., Reed-Muller, BCH, Convolution, Turbo, LDPC and Polar codes: each is a linear code and represents a mathematical breakthrough. The impact on humanity is huge: each of these codes has been used in global wireless communication standards (satellite, WiFi, cellular). Traditionally, the design of codes has been driven by human-ingenuity and hence the progress is sporadic. Can we automate and accelerate this process of discovering codes?

In this talk, I will talk about KO codes, a new family of computationally efficient deep-learning driven codes that outperform the state-of-the-art reliability performance on the standardized AWGN channel. KO codes beat state-of-the-art Reed-Muller and Polar codes, under the low-complexity successive cancellation decoding, in the challenging short-to-medium block length regime on the AWGN channel. We show that the gains of KO codes are primarily due to the nonlinear mapping of information bits directly to transmit real symbols (bypassing modulation) and yet possess an efficient, high performance decoder. The key technical innovation that renders this possible is design of a novel family of neural architectures inspired by the computation tree of the Kronecker Operation (KO) central to Reed-Muller and Polar codes. These architectures pave way for the discovery of a much richer class of hitherto unexplored nonlinear algebraic structures. And more interestingly, despite having a lot of encoding and decoding structure, KO codes exhibit striking similarity to random Gaussian codes!


To avoid Zoom-bombing, we ask attendees to sign in via the above URL to receive the Zoom meeting details by email.

Please join us for a coffee half hour starting at 3:30pm at the Grove outside Packard.

Date and Time: 
Thursday, October 7, 2021 - 4:00pm
Venue: 
Packard 101 + Zoom (registration req'd)

ISL Colloquium: Sequential Decision Making: How Much Adaptivity Is Needed Anyways?

Topic: 
Sequential Decision Making: How Much Adaptivity Is Needed Anyways?
Abstract / Description: 

Adaptive stochastic optimization under partial observability is one of the fundamental challenges in artificial intelligence and machine learning with a wide range of applications, including active learning, optimal experimental design, interactive recommendations, viral marketing, Wikipedia link prediction, and perception in robotics, to name a few. In such problems, one needs to adaptively make a sequence of decisions while taking into account the stochastic observations collected in previous rounds. For instance, in active learning, the goal is to learn a classifier by carefully requesting as few labels as possible from a set of unlabeled data points. Similarly, in experimental design, a practitioner may conduct a series of tests in order to reach a conclusion. Even though it is possible to determine all the selections ahead of time before any observations take place (e.g., select all the data points at once or conduct all the medical tests simultaneously), so-called a priori selection, it is more efficient to consider a fully adaptive procedure that exploits the information obtained from past selections in order to make a new selection. In this talk, we introduce semi-adaptive policies, for a wide range of decision-making problems, that enjoy the power of fully sequential procedures while performing exponentially fewer adaptive rounds.

 

Note: This talk will be held in person in Packard 101, and has been pushed back to 4:45pm to accommodate the new class schedule.

The talk will be streamed on Zoom for those who cannot attend (registration required).


This talk is hosted by the ISL Colloquium. To receive talk announcements, subscribe to the mailing list isl-colloq@lists.stanford.edu.


Please join us for a coffee half hour starting at 4:15pm at the Bytes outdoor tables outside of Packard.

Date and Time: 
Thursday, September 30, 2021 - 4:45pm
Venue: 
Packard 101

ISL Colloquium: Interpolation Phase Transition in Neural Networks: Memorization and Generalization

Topic: 
Interpolation Phase Transition in Neural Networks: Memorization and Generalization
Abstract / Description: 

A mystery of modern neural networks is their surprising generalization power in overparametrized regime: they comprise so many parameters that they can interpolate the training set, even if actual labels are replaced by purely random ones; despite this, they achieve good prediction error on unseen data.

To demystify the above phenomena, we focus on two-layer neural networks in the neural tangent (NT) regime. Under a simple data model where n inputs are d-dimensional isotropic vectors and there are N hidden neurons, we show that as soon as Nd >> n, the minimum eigenvalue of the empirical NT kernel is bounded away from zero, and therefore the network can exactly interpolate arbitrary labels.

Next, we study the generalization error of NT ridge regression (including min-$ell_2$ norm interpolation). We show that in the same overparametrization regime Nd >> n, in terms of generalization errors, NT ridge regression is well approximated by kernel ridge regression (infinite-width kernel), which is in further we approximated by polynomial ridge regression. A surprising phenomenon is a "self-induced" regularization due to the high-degree components of the activation function.

Link to the ArXiv paper: https://arxiv.org/abs/2007.12826


This talk is hosted by the ISL Colloquium. To receive talk announcements, subscribe to the mailing list isl-colloq@lists.stanford.edu.

Date and Time: 
Thursday, September 23, 2021 - 4:30pm
Venue: 
Packard 101

ISL Colloquium presents "The Hidden Convex Optimization Landscape of Deep Neural Networks"

Topic: 
The Hidden Convex Optimization Landscape of Deep Neural Networks
Abstract / Description: 

The popularity of Deep Neural Networks (DNNs) continues to grow as a result of the great empirical success in a large number of machine learning tasks. However, despite their prevalence in machine learning and the dramatic surge of interest, there are major gaps in our understanding of the fundamentals of neural net models. Understanding the mechanism behind their extraordinary generalization properties remains an open problem. A significant challenge arises in the non-convexity of training DNNs. In non-convex optimization, the choice of optimization method and its internal parameters such as initialization, mini-batching and step sizes have a considerable effect on the quality of the learned model. This is in sharp contrast to convex optimization problems, where these optimization parameters have no effect, and globally optimal solutions can be obtained in a very robust, efficient, transparent and reproducible manner.

In this talk, we introduce exact convex optimization formulations of multilayer neural network training problems. We show that two and three layer neural networks with ReLU or polynomial activations can be globally trained via convex programs with the number of variables polynomial in the number of training samples and number of hidden neurons. Our results provide an equivalent characterization of neural networks as convex models where a mixture of locally linear models are fitted to the data with sparsity inducing convex regularization. Moreover, we show that certain standard two and three layer convolutional neural networks can be globally optimized in fully polynomial time. We discuss extensions to batch normalization and generative adversarial networks. Finally, we present numerical simulations verifying our claims and illustrating that standard local search heuristics such as stochastic gradient descent can be inefficient compared to the proposed convex program.

Date and Time: 
Thursday, June 3, 2021 - 4:30pm

ISL Colloquium: Multi-Scale Methods for Machine Learning

Topic: 
Multi-Scale Methods for Machine Learning
Abstract / Description: 

Many modern applications require us to very quickly find relevant results from an enormous output space of potential candidates, for example, finding the best matching product from a large catalog or suggesting related search phrases on a search engine. The size of the output space for these problems can be in the millions to billions. Moreover, observational or training data is often limited for many of the so-called "long-tail" of items in the output space. Given the inherent paucity of training data for most of the items in the output space, developing machine learning models that perform well for spaces of this size is a contemporary challenge. In this talk, I will present a multi-scale machine learning framework called Prediction for Enormous and Correlated Output Spaces (PECOS). PECOS proceeds by first building a hierarchy over the output space using unsupervised learning, and then learning a machine learning model that makes predictions at each level of the hierarchy. Finally, the multi-scale predictions are combined to obtain an overall predictive model. This leads to an inference method that scales logarithmically with the size of the output space. A key to obtaining high performance is leveraging sparsity and developing highly efficient sparse matrix routines.

Date and Time: 
Thursday, May 20, 2021 - 4:30pm

ISL Colloquium: Interior Point Methods for Nearly Linear Time Algorithms

Topic: 
Interior Point Methods for Nearly Linear Time Algorithms
Abstract / Description: 

Linear programming is a foundational continuous optimization problem and special cases, e.g. maximum cardinality bipartite matching, are among the most fundamental problems in combinatorial optimization. In this talk, I will survey recent advances in solving these problems using interior point methods. I will discuss how new interior point methods can be leveraged to efficiently reduce these problems to data structures problems which can be solved efficiently with techniques from randomized numerical linear algebra and graph theory. This talk will highlight recent joint work which showed that linear programs with d variables and n constraints can be solved with high probability to high precision in time Otilde(nd + poly(d)) and that a variety of graph problems, e.g. maximum flow and optimal transport, on n-node -m-edge graphs can be solved to with high probability to high precision in time Otilde(m + n^1.5). These results constitute the first polynomial time methods for solving these problems to high precision which run in nearly-linear time on sufficiently large and dense instances. No previous experience with interior point methods required.
This talk will touch upon joint work with Jan van den Brand, Yin Tat Lee, Yang P. Liu, Danupon Nanongkai, Richard Peng, Thatchaphol Saranurak, Zhao Song, and Di Wang including 2009.01802, 2002.02304, and 2101.05719.

Date and Time: 
Thursday, May 6, 2021 - 4:30pm

Pages

IT-Forum

ISL Colloquium: KO codes: Inventing Non-linear Encoding and Decoding for Reliable Wireless Communication via Deep-learning

Topic: 
KO codes: Inventing Non-linear Encoding and Decoding for Reliable Wireless Communication via Deep-learning
Abstract / Description: 

Landmark codes underpin reliable physical layer communication, e.g., Reed-Muller, BCH, Convolution, Turbo, LDPC and Polar codes: each is a linear code and represents a mathematical breakthrough. The impact on humanity is huge: each of these codes has been used in global wireless communication standards (satellite, WiFi, cellular). Traditionally, the design of codes has been driven by human-ingenuity and hence the progress is sporadic. Can we automate and accelerate this process of discovering codes?

In this talk, I will talk about KO codes, a new family of computationally efficient deep-learning driven codes that outperform the state-of-the-art reliability performance on the standardized AWGN channel. KO codes beat state-of-the-art Reed-Muller and Polar codes, under the low-complexity successive cancellation decoding, in the challenging short-to-medium block length regime on the AWGN channel. We show that the gains of KO codes are primarily due to the nonlinear mapping of information bits directly to transmit real symbols (bypassing modulation) and yet possess an efficient, high performance decoder. The key technical innovation that renders this possible is design of a novel family of neural architectures inspired by the computation tree of the Kronecker Operation (KO) central to Reed-Muller and Polar codes. These architectures pave way for the discovery of a much richer class of hitherto unexplored nonlinear algebraic structures. And more interestingly, despite having a lot of encoding and decoding structure, KO codes exhibit striking similarity to random Gaussian codes!


To avoid Zoom-bombing, we ask attendees to sign in via the above URL to receive the Zoom meeting details by email.

Please join us for a coffee half hour starting at 3:30pm at the Grove outside Packard.

Date and Time: 
Thursday, October 7, 2021 - 4:00pm
Venue: 
Packard 101 + Zoom (registration req'd)

ISL Colloquium: Sequential Decision Making: How Much Adaptivity Is Needed Anyways?

Topic: 
Sequential Decision Making: How Much Adaptivity Is Needed Anyways?
Abstract / Description: 

Adaptive stochastic optimization under partial observability is one of the fundamental challenges in artificial intelligence and machine learning with a wide range of applications, including active learning, optimal experimental design, interactive recommendations, viral marketing, Wikipedia link prediction, and perception in robotics, to name a few. In such problems, one needs to adaptively make a sequence of decisions while taking into account the stochastic observations collected in previous rounds. For instance, in active learning, the goal is to learn a classifier by carefully requesting as few labels as possible from a set of unlabeled data points. Similarly, in experimental design, a practitioner may conduct a series of tests in order to reach a conclusion. Even though it is possible to determine all the selections ahead of time before any observations take place (e.g., select all the data points at once or conduct all the medical tests simultaneously), so-called a priori selection, it is more efficient to consider a fully adaptive procedure that exploits the information obtained from past selections in order to make a new selection. In this talk, we introduce semi-adaptive policies, for a wide range of decision-making problems, that enjoy the power of fully sequential procedures while performing exponentially fewer adaptive rounds.

 

Note: This talk will be held in person in Packard 101, and has been pushed back to 4:45pm to accommodate the new class schedule.

The talk will be streamed on Zoom for those who cannot attend (registration required).


This talk is hosted by the ISL Colloquium. To receive talk announcements, subscribe to the mailing list isl-colloq@lists.stanford.edu.


Please join us for a coffee half hour starting at 4:15pm at the Bytes outdoor tables outside of Packard.

Date and Time: 
Thursday, September 30, 2021 - 4:45pm
Venue: 
Packard 101

IT-Forum: "Between tractable and intractable problems in reinforcement learning"

Topic: 
Between tractable and intractable problems in reinforcement learning
Abstract / Description: 

Markov decision processes (MDPs) capture some of the most important aspects of decision making under uncertainty and as such they are at the heart of many efforts to decision making under uncertainty. However, MDPs are "flat" with no structure and as such, planning and learning in MDPs with multidimensional state spaces, common in applications, is provably intractable. Yet, reinforcement learning methods have been quite successful in providing strong solutions to some of these seemingly intractable problems. In this talk I will present my view of how to think about these successes by presenting a framework where the key idea is to give algorithms hints that can create backdoors to crack otherwise intractable problems. The talk will then dive into categorizing hints based on whether they can indeed succeed at doing this for the special case when the hints are given in the form of constraints on how value functions look like in the context of planning with generative models, also known as simulation optimization. As we shall see, seemingly minor differences between hints can cause some hints to work, while others fail.

Date and Time: 
Thursday, June 10, 2021 - 4:30pm

IT-Forum: "The Gittins Policy is Nearly Optimal in the M/G/k under Extremely General Conditions"

Topic: 
The Gittins Policy is Nearly Optimal in the M/G/k under Extremely General Conditions
Abstract / Description: 

The Gittins scheduling policy minimizes the mean response in the single-server M/G/1 queue in a wide variety of settings. Most famously, Gittins is optimal when preemption is allowed and service requirements are unknown but drawn from a known distribution. Gittins is also optimal much more generally, adapting to any amount of available information and any preemption restrictions. However, scheduling to minimize mean response time in a multiserver setting, specifically the central-queue M/G/k, is a much more difficult problem.

In this work we give the first general analysis of Gittins in the M/G/k. Specifically, we show that under extremely general conditions, Gittins's mean response time in the M/G/k is at most its mean response time in the M/G/1 plus a term that grows logarithmically in the heavy-traffic limit, namely as the system load approaches capacity. A consequence of this result is that Gittins is optimal in the heavy-traffic M/G/k if the service requirement distribution has finite (2 + ε)th moment for any ε > 0. This is the most general result on minimizing mean response time in the M/G/k to date.

To prove our results, we combine properties of the Gittins policy and Palm calculus in a novel way. Notably, our technique overcomes the limitations of tagged job methods that were used in prior scheduling analyses.

Joint work with Isaac Grosof and Mor Harchol-Balter. Paper link: https://ziv.codes/publications/#the-gittins-policy-is-nearly-optimal-in-the-mgk-under-extremely-general-conditions

Date and Time: 
Friday, May 21, 2021 - 1:00pm to Saturday, May 22, 2021 - 12:55pm

Algorithms & Friends Seminar presents "Modeling the Heterogeneity in COVID-19’s Reproductive Number and Its Impact on Predictive Scenarios"

Topic: 
Modeling the Heterogeneity in COVID-19’s Reproductive Number and Its Impact on Predictive Scenarios
Abstract / Description: 

The correct evaluation of the reproductive number R for COVID-19 — which characterizes the average number of secondary cases generated by each typical primary case— is central in the quantification of the potential scope of the pandemic and the selection of an appropriate course of action. In most models, R is modelled as a universal constant for the virus across outbreak clusters and individuals— effectively averaging out the inherent variability of the transmission process due to varying individual contact rates, population densities, demographics, or temporal factors amongst many. Yet, due to the exponential nature of epidemic growth, the error due to this simplification can be rapidly amplified and lead to inaccurate predictions and/or risk evaluation. From the statistical modeling perspective, the magnitude of the impact of this averaging remains an open question: how can this intrinsic variability be percolated into epidemic models, and how can its impact on uncertainty quantification and predictive scenarios be better quantified? In this talk, we discuss a Bayesian perspective on this question, creating a bridge between the agent-based and compartmental approaches commonly used in the literature. After deriving a Bayesian model that captures at scale the heterogeneity of a population and environmental conditions, we simulate the spread of the epidemic as well as the impact of different social distancing strategies, and highlight the strong impact of this added variability on the reported results. We base our discussion on both synthetic experiments — thereby quantifying of the reliability and the magnitude of the effects — and real COVID-19 data.


 

Hosted by the Algorithms and Friends Seminar

Date and Time: 
Monday, April 5, 2021 - 12:00pm to Tuesday, April 6, 2021 - 11:55am

ISL Colloquium presents "Finding Global Minima via Kernel Approximations"

Topic: 
Finding Global Minima via Kernel Approximations
Abstract / Description: 

We consider the global minimization of smooth functions based solely on function evaluations. Algorithms that achieve the optimal number of function evaluations for a given precision level typically rely on explicitly constructing an approximation of the function which is then minimized with algorithms that have exponential running-time complexity. In this paper, we consider an approach that jointly models the function to approximate and finds a global minimum. This is done by using infinite sums of square smooth functions and has strong links with polynomial sum-of-squares hierarchies. Leveraging recent representation properties of reproducing kernel Hilbert spaces, the infinite-dimensional optimization problem can be solved by subsampling in time polynomial in the number of function evaluations, and with theoretical guarantees on the obtained minimum. (Joint work with Alessandro Rudi and Ulysse Marteau-Ferey).

Date and Time: 
Thursday, April 1, 2021 - 10:00am to Friday, April 2, 2021 - 9:55am

IT-Forum presents "Approximating cross-validation: guarantees for model assessment and selection"

Topic: 
Approximating cross-validation: guarantees for model assessment and selection
Abstract / Description: 

Cross-validation (CV) is the de facto standard for selecting accurate predictive models and assessing model performance. However, CV suffers from a need to repeatedly refit a learning procedure on a large number of training datasets. To reduce the computational burden, a number of works have introduced approximate CV procedures that simultaneously reduce runtime and provide model assessments comparable to CV when the prediction problem is sufficiently smooth. An open question however is whether these procedures are suitable for model selection. In this talk, I'll describe (i) broad conditions under which the model selection performance of approximate CV nearly matches that of CV, (ii) examples of prediction problems where approximate CV selection fails to mimic CV selection, and (iii) an extension of these results and the approximate CV framework more broadly to non-smooth prediction problems like L1-regularized empirical risk minimization.

Date and Time: 
Thursday, March 18, 2021 - 4:30pm
Venue: 
Zoom: register to receive ID

IT Forum presents "Robust Learning from Batches – The Best Things in Life are (Almost) Free"

Topic: 
Robust Learning from Batches – The Best Things in Life are (Almost) Free
Abstract / Description: 

In many applications, including natural language processing, sensor networks, collaborative filtering, and federated learning, data are collected in batches, some potentially corrupt, biased, or even adversarial. Learning algorithms for this setting have therefore garnered considerable recent attention. We develop a general framework for robust learning from batches, and determine the least number of samples required for robust density estimation and classification over both discrete and continuous domains. Perhaps surprisingly, we show that robust learning can be achieved with essentially the same number of samples as required for genuine data. For the important problems of learning discrete and piecewise-polynomial densities, and of interval-based classification, we achieve these limits with polynomial-time algorithms.

Based on joint work with Ayush Jain.

Date and Time: 
Thursday, March 11, 2021 - 4:30pm

Algorithms & Friends Seminar presents "How fast do algorithms improve?"

Topic: 
How fast do algorithms improve?
Abstract / Description: 

Algorithms are one of the fundamental building blocks of computing. But current evidence about how fast algorithms improve is anecdotal, using small numbers of case studies to extrapolate. In this work, we gather data from 57 textbooks and more than 1,137 research papers to present the first systematic view of algorithm progress ever assembled. There is enormous variation. Around half of all algorithm families experience little or no improvement. At the other extreme, 13% experience transformative improvements, radically changing how and where they can be used. Overall, we find that, for moderate-sized problems, 30% to 45% of algorithmic families had improvements comparable or greater than those that users experienced from Moore's Law and other hardware advances.

Joint work with Yash M. Sherry.

Date and Time: 
Monday, February 22, 2021 - 12:00pm to Tuesday, February 23, 2021 - 11:55am

IT Forum presents "Distribution-Free, Risk-Controlling Prediction Sets"

Topic: 
Distribution-Free, Risk-Controlling Prediction Sets
Abstract / Description: 

To communicate instance-wise uncertainty for prediction tasks, we show how to generate set-valued predictions for black-box predictors that control the expected loss on future test points at a user-specified level. Our approach provides explicit finite-sample guarantees for any dataset by using a holdout set to calibrate the size of the prediction sets. This framework enables simple, distribution-free, rigorous error control for many tasks, and we demonstrate it in five large-scale machine learning problems: (1) classification problems where some mistakes are more costly than others; (2) multi-label classification, where each observation has multiple associated labels; (3) classification problems where the labels have a hierarchical structure; (4) image segmentation, where we wish to predict a set of pixels containing an object of interest; and (5) protein structure prediction.

Date and Time: 
Friday, February 19, 2021 - 1:00pm to Saturday, February 20, 2021 - 12:55pm

Pages

Optics and Electronics Seminar

Applied Physics 483 Optics & Electronics Seminar:Actively Tunable and Time-Modulated Flat Optics for Beam Steering, Multiplexing, and Polarization Conversion

Topic: 
Actively Tunable and Time-Modulated Flat Optics for Beam Steering, Multiplexing, and Polarization Conversion
Abstract / Description: 

Phase gradient metasurfaces are flat optical structures with potential to manipulate amplitude, phase, and polarization of electromagnetic waves using arrays of subwavelength nanoantennas. Currently most metasurfaces are 'static' and have functions that are fixed at the time of fabrication. By making antenna arrays tunable or reconfigurable in their phase, amplitude, and polarization response through incorporation of electro-optical effects, one can achieve spatiotemporal control of the phase gradient after fabrication. Time modulation can be either be 'quasi-static', where temporal variations are sufficiently slow that they do not change the scattered light frequency, or in a regime where the modulation rate is high enough to generate new frequencies. In this way, time modulation opens a four-dimensional active metasurface design space where control over the spectral content of scattered light, in addition to its spatial features, can extend light manipulation to encompass space-time photonic transitions. New materials are also adding new functions: the excitonic birefringence of the intriguing van der Waals semiconductor black phosphorus has enabled actively tunable spectrally broadband polarization conversion over nearly half the Poincaré sphere. Both linear to circular and cross-polarization conversion with voltage are possible, demonstrating dynamic access to polarization diversity.

Date and Time: 
Monday, October 18, 2021 - 4:15pm

Applied Physics 483 Optics & Electronics Seminar: Meta-optics: From Flat Lenses to Structured Light and Dark

Topic: 
Meta-optics: From Flat Lenses to Structured Light and Dark
Abstract / Description: 

Subwavelength spaced arrays of nanostructures, known as metasurfaces, provide a new basis for recasting optical components into thin planar elements, easy to optically align and control aberrations, leading to a major reduction in system complexity and footprint as well as the introduction of new optical functions. The planarity of flat optics will lead to the unification of semiconductor manufacturing and lens making, where the planar technology to manufacture computer chips will be adapted to make CMOS compatible metasurface based optical components for high volume markets like cell phones. New polarization sensitive and depth cameras will be discussed. Metasurfaces also offer fresh opportunities for structuring light as well as dark. I will discuss spin to total orbital angular momentum (OAM) converters and high OAM lasing, as well as flat devices that enable light’s spin and OAM to evolve, simultaneously, from one state to another along the propagation direction. Finally, the demonstration of 2D phase and polarization singularities and the unique applications that they will open up will be discussed

Date and Time: 
Monday, October 11, 2021 - 4:15pm

Applied Physics 483 Optics & Electronics Seminar: Extreme wave phenomena enabled by broken symmetries

Topic: 
Extreme wave phenomena enabled by broken symmetries
Abstract / Description: 

In this talk, I discuss the role of symmetry breaking in nano-optics, photonics, electromagnetics and acoustics, to tailor and engineer wave phenomena. I will overview a range of low-symmetry natural and artificial materials whose interactions with light and sound are tailored and enhanced through geometrical and/or temporal symmetry breaking. Special opportunities arise when considering systems in which light and matter are strongly coupled, as in the case of polaritonics, for which extreme linear and nonlinear responses are unveiled by controlling the underlying symmetries. I will also discuss the role of symmetry breaking to induce nonreciprocal and topological wave phenomena and the various opportunities they enable for photonic technologies.

Date and Time: 
Monday, October 4, 2021 - 12:00pm

SPRC & SOS Seminar: Trace Gas Flux Measurements in Artic Ecosystems – Current Applications and Future Perspectives

Topic: 
Trace Gas Flux Measurements in Artic Ecosystems – Current Applications and Future Perspectives
Abstract / Description: 

The exchanges of carbon dioxide (CO2) and methane (CH4) between arctic ecosystems and the atmosphere are sizeable and may if they change may alter the further development of climate warming. These fluxes take place between the atmospheric background of these trace gases and a very large reservoir of organic carbon stored in arctic soils and sediments. The stored carbon amounts to more than twice the current global atmospheric burden of CO2. Therefore, accurate measurements of the fluxes and how they vary temporally and spatially is key to understanding possible ecosystem impacts on the atmospheric mixing ratios and hence climate.
This presentation will detail the current state of the global CO2 and CH4 budget and review methods applied in quantifying the arctic trace gas flux components. The presentation will show new developments in the attempts to use UAV's to help improve spatial coverage of measured fluxes. The challenges in applying the laser techniques needed for the precise and fast trace gas measurements under true arctic conditions will be discussed.

Date and Time: 
Tuesday, May 4, 2021 - 11:00am to Wednesday, May 5, 2021 - 10:55am

Optics & Electronics seminar: Inverse Designed Integrated Photonics

Topic: 
[AP483] Inverse Designed Integrated Photonics
Abstract / Description: 

Photonics with superior properties can be implemented in a variety of old (silicon, silicon nitride) and new (silicon carbide, diamond) photonic materials by combining state-of-the- art photonics optimization techniques (photonics inverse design) with new fabrication approaches. In addition to making photonics more robust (e.g., to errors in fabrication and variation in temperature), more compact, and more efficient, this approach can also enable new functionalities. While in our early work we focused on inverse design and demonstration of individual photonic devices, our more recent work focused on scaling it to photonic integrated circuits fabricated in a commercial semiconductor foundry. We illustrate this with several examples, including optical interconnects based on a combination of mode and wavelength division multiplexing, and photonic chips for optical beam steering.


 

Spring 2021 speakers organized by Prof. David A.B. Miller

Date and Time: 
Monday, May 24, 2021 - 4:15pm

Optics & Electronics seminar: Energy Efficient, Multi-Terabit Photonic Connectivity for Disaggregated Computing

Topic: 
[AP483] Energy Efficient, Multi-Terabit Photonic Connectivity for Disaggregated Computing
Abstract / Description: 

High performance data centers are increasingly bottlenecked by the energy and communications costs of interconnection networks. Integrated silicon photonics with dense wavelength-division multiplexing offer the opportunity of optical connectivity that directly delivers high off-chip communication bandwidth densities with low power consumption. We introduce the concept of embedded photonics for deeply disaggregated architectures. Beyond alleviating the bandwidth/energy bottlenecks, the new architectural approach enables flexible connectivity tailored for specific applications.


 

Spring 2021 speakers organized by Prof. David A.B. Miller

Date and Time: 
Monday, May 3, 2021 - 4:15pm

Optics & Electronics seminar: End to End Optimization of Optics and Algorithms

Topic: 
[AP483] End to End Optimization of Optics and Algorithms
Abstract / Description: 

Neural networks and other advanced image processing algorithms excel in a wide variety of computer vision and imaging applications, but their high performance also comes at a high computational cost, and their success is sometimes limited. In this talk, we explore hybrid optical-digital strategies to computational imaging that outsource parts of the algorithm into the optical domain. Using such a co-design of optics and image processing, we can design application-domain-specific cameras or compute parts of a convolutional neural network in optics. Optical computing happens at the speed of light and without any memory or power requirements, thereby opening new directions for intelligent imaging systems.


 

Spring 2021 speakers organized by Prof. David A.B. Miller

Date and Time: 
Monday, April 26, 2021 - 4:15pm

Optics & Electronics seminar: Playing Hide-and-Seek at the Nanoscale – Tailored Field Landscapes for Precise Particle Tracking and More

Topic: 
[AP483] Playing Hide-and-Seek at the Nanoscale – Tailored Field Landscapes for Precise Particle Tracking and More
Abstract / Description: 

Intensity, phase, and polarization of electromagnetic fields can be tailored to form bespoke distributions. This spatial structure of light is an intriguing playground. It finds a wide range of applications in optical communications, sensing, imaging, and beyond. However, the real beauty of structured fields comes to light when considering strongly confined electromagnetic fields, which naturally feature complex three-dimensional distributions. These engineered light fields can be utilized, for example, to selectively excite individual nanosystems, extending the range of possible applications even further by enabling advanced single-particle spectroscopy, nanoscale traffic control, nano-metrology, and more.

In this talk, we introduce a novel scheme for ultra-precise particle localization and tracking, which is based on the interaction of structured light and individual nanoparticles. We show that by utilizing the strongly position-dependent scattering pattern as a ruler, we can retrieve the exact particle position from the far-field scattering signal. Besides the fundamental ingredients and recipe of this technique, we also highlight selected next steps and future plans. For instance, we also discuss the fundamental idea behind next generation camera technology to boost the capabilities of our nanometrology schemes. These novel pixels and cameras based on light-processing circuitry are jointly developed, together with other European and international experts, as part of the 'SuperPixels' project (https://www.superpixels.org/). They will allow for a simultaneous measurement of polarization and phase distributions in addition to light's intensity.

[This project has received partial funding from the European Commission Horizon 2020 research and innovation program under the Future and Emerging Technologies Open Grant Agreement Super-Pixels No. 829116]


 

Spring 2021 speakers organized by Prof. David A.B. Miller

Date and Time: 
Monday, April 19, 2021 - 12:00pm to Tuesday, April 20, 2021 - 11:55am

Optics & Electronics seminar: Semiconductor Nanocrystal Optoelectronics: A Journey from Colloidal Quantum Dots to Wells

Topic: 
[AP483] Semiconductor Nanocrystal Optoelectronics: A Journey from Colloidal Quantum Dots to Wells
Abstract / Description: 

Semiconductor nanocrystals have attracted great interest for color conversion and enrichment in quality lighting and displays. Optical properties of these solution‑processed nanostructures are conveniently controlled by tailoring their size, shape, and composition in an effort to realize high‑performance light generation and lasing. These colloids span different types and heterostructures of semiconductors in the forms of quantum dots and rods to the latest sub‑family of nanocrystals, the colloidal quantum wells (CQWs). In this talk, we will introduce the emerging field of semiconductor nanocrystal optoelectronics, with most recent examples of their photonic structures and optoelectronic devices employing such atomically‑flat, tightly‑confined, quasi‑two‑dimensional CQWs, also popularly nick-named 'nanoplatelets'. Among their various extraordinary features, we will show that these CQWs enable record high optical gain coefficients [1] and can achieve gain thresholds at the level of sub‑single exciton population per CQW on average [2], empowered by carefully engineering their heterostructure [3]. Next, we will present a new, powerful, large-area self‑assembly tool for orientation controlling of these nanoplatelets [4], which provides us with the ability to tune and master their excitonic properties in their ensemble, as well as the level of achievable energy transfer among them and with other nearby species. Using three‑dimensional constructs of face‑down self‑assembled slabs of CQWs with monolayer precision, we will demonstrate ultrathin optical gain media and lasers of these oriented CQW assemblies [5]. Finally, we will show record high‑efficiency colloidal LEDs using CQWs employed as the electrically‑driven active emitter layer [6] and record low-threshold solution lasers using the same CQWs employed as the optically‑pumped fluidic gain medium [7]. Given their current accelerating progress, these solution‑processed quantum well materials hold great promise to challenge their epitaxial thin‑film counterparts in semiconductor optoelectronics in the near future.

[1] B. Guzelturk et al., HVD, Nano Letters 19, 277 (2019)
[2] N. Taghipour et al., HVD, Nature Comm 11, 3305 (2020)
[3] Y. Altıntas et al., HVD, ACS Nano 13, 10662 (2019)
[4] O. Erdem et al., HVD, Nano Letters 19, 4297 (2019)
[5] O. Erdem et al., HVD, Nano Letters 20, 6459 (2020)
[6] B. Liu et al., HVD, Advanced Materials 32, 1905824 (2020)
[7] J. Maskoun et al., HVD, Advanced Materials (2021), in print, DOI:(10.1002/adma.202007131)


Spring 2021 speakers organized by Prof. David A.B. Miller

Date and Time: 
Monday, April 12, 2021 - 12:00pm to Tuesday, April 13, 2021 - 11:55am

Pages

SCIEN Talk

SCIEN presents "Neural Methods for Reconstruction and Rendering of Real World Scenes"

Topic: 
Neural Methods for Reconstruction and Rendering of Real World Scenes
Abstract / Description: 

In this presentation, I will talk about some of the recent work we did on new methods for reconstructing computer graphics models of real world scenes from sparse or even monocular video data. These methods are based of bringing together neural network-based and explicit model-based approaches. I will also talk about new neural rendering approaches that combine explicit model-based and neural network based concepts for image formation in new ways. They enable new means to synthesize highly realistic imagery and videos of real work scenes under user control.

Date and Time: 
Wednesday, November 17, 2021 - 10:00am

SCIEN presents "Differentiable Simulation of Light"

Topic: 
Differentiable Simulation of Light
Abstract / Description: 

Inverse problems involving light abound throughout many scientific disciplines. Typically, a set of images captured by an instrument must be mathematically processed to reveal some property of our physical reality. This talk will provide an introduction and overview of the emerging field of differentiable physically based rendering, which has the potential of substantially improving the accuracy of such calculations.
Methods in this area propagate derivative information through physical light simulations to solve optimization problems. While still very much a work in progress, advances in the last years have led to increasingly efficient and numerically robust methods that can begin to tackle interesting real-world problems. I will give an overview of recent progress and open problems.

Date and Time: 
Wednesday, November 10, 2021 - 10:00am

SCIEN presents "Freeform Optics for Imaging and Metaform Optics in Near-Eye Displays"

Topic: 
Freeform Optics for Imaging and Metaform Optics in Near-Eye Displays
Abstract / Description: 

Freeform optics has set a new path for optical system design across a wide range of applications spanning from microscopy to space optics, including the billion $ consumer market of near-eye displays for augmented reality that set us on this technology path in the first place. Today, freeform optics have been demonstrated to yield compact, achromatic, and high-performance imaging systems that are poised to enable the science of tomorrow. This talk will introduce freeform optics and highlight emerging design methods. We will then present success stories in digital-viewfinder, imager, and spectrometer designs, which we anticipate will ignite discussion and stimulate cooperation in enabling knowledge in freeform optics. Building on this foundation, we will introduce the concept of a metaform to address a need in near-eye displays.

Date and Time: 
Wednesday, November 3, 2021 - 4:30pm

SCIEN presents "Design Tools for Material Appearance"

Topic: 
Design Tools for Material Appearance
Abstract / Description: 

The design of material appearance for both virtual and physical design remains a challenging problem. There aren’t straightforward intuitive techniques as there are in  geometric design where shapes can be sketched or assembled from geometric primitives. In this talk I will present a series of contributions to developing intuitive appearance design tools. This includes studies of material appearance perception which form the basis of the development of perceptual axes for reflectance distribution design. I will also present novel interfaces for design including hybrid slider/image navigation and augmented reality interfaces. I will discuss the unique problems involved in designing appearance for objects to be physically manufactured rather than simply displayed in virtual environments.  Finally, I will show how exemplars of spatially varying materials can be inverted to produce procedural models.

Date and Time: 
Wednesday, October 27, 2021 - 4:30pm

SCIEN welcomes Prof Michelle Digman

Topic: 
Metabolic imaging using the phasor approach to FLIM and tracking phenotypic change in mitochondria in cancer cells with Mitometer
Abstract / Description: 

In this talk I will discuss the phasor approach technique in fluorescence lifetime imaging microscopy (FLIM) as a novel method to measure metabolic alteration as a function of extracellular matrix (ECM) mechanics. To measure mitochondria contribution to metabolic switching, we developed a new algorithm called "mitometer" that is unbiased and allows for automated segmentation and tracking of mitochondria in live cell 2D and 3D time-lapse images. I will show how Mitometer measures mitochondria of triple-negative breast cancer cells. Results show they are faster, more directional, and more elongated than those in their receptor-positive counterparts. Furthermore, Mitometer shows that mitochondrial motility and morphology in breast cancer, but not in normal breast epithelia, correlate with fractions of the reduced form of NADH. Together, the automated segmentation and tracking algorithms and the innate user interface make Mitometer a broadly accessible tool.

Date and Time: 
Wednesday, October 20, 2021 - 4:30pm

SCIEN presents "Polarized Computational Imaging and Beyond"

Topic: 
Polarized Computational Imaging and Beyond
Abstract / Description: 

Is computational imaging the next frontier in computer vision? As materials, lighting, and geometry become more complex an ordinary camera starts to be the limiting step in the vision pipeline. A case in point are transparent objects which cannot be seen by an ordinary camera (which mimics the human eye). However, a plenoptic camera that captures polarization spawns a unique texture to previously invisible objects. The polarized texture results from complex light-matter interactions in shape and refractive index. Such texture can be subsequently modeled and “baked” into neural pipelines to enable inference on transparent objects, a decades-open task in traditional computer vision. WIth polarization simply scratching the surface of what computational imaging can do, we end with a discussion of how broader forms of plenoptic data can be leveraged in future neural pipelines.

Date and Time: 
Wednesday, October 13, 2021 - 4:30pm

SCIEN Colloquium and EE 292E presents "Human vision at a glance"

Topic: 
Human vision at a glance
Abstract / Description: 

Recent advances in human vision research have pointed toward a theory that unifies many aspects of vision that are relevant to applications. According to this theory, loss of information in peripheral vision determines performance on many visual tasks. This theory subsumes old concepts such as visual saliency, selective attention, and change blindness. It predicts the rich details we have access to at a glance. Furthermore, it provides insight into tasks not commonly studied in human vision, such as the ability to comprehend connections in a graph, or to compare information across space.

Date and Time: 
Wednesday, October 6, 2021 - 4:30pm

SCIEN and EE292E presents "Entrepreneurship, AI, and Agriculture: How ML is Changing Industries"

Topic: 
Entrepreneurship, AI, and Agriculture: How ML is Changing Industries
Abstract / Description: 

In this talk, Lee will go through 3 parts:

  1. His entrepreneurship journey and the formation of Blue River Technology from a class at Stanford to an idea worth working on, to a company operating on 10% of the lettuce in the US.
  2. The computer vision technology and journey behind the see and spray system up until acquisition
  3. Advances in control systems
Date and Time: 
Wednesday, September 29, 2021 - 4:30pm

Stanford Medical Mixed Reality (SMMR) Panel Discussion Series

Topic: 
Haptics for Medical XR
Abstract / Description: 

Stanford Medical Mixed Reality (SMMR) invites you to their next virtual panel discussion series about groundbreaking mixed reality technology and innovation in medicine and how it impacts patients, clinicians, and the healthcare industry.

The event will start with a one-hour panel discussion featuring Prof. Allison Okamura, director of Stanford's Collaborative Haptics and Robotics in Medicine (CHARM) Lab; Dr. Danny Goel of PrecisionOS, a Vancouver-based company developing a VR surgical training platform; Craig Douglass of Contact CI, a Cincinnati-based company developing a haptic glove for immersive technologies; and Govinda Payyavula ofIntuitive Surgical, a Bay Area-based company and leader in robotic surgery systems. This panel will be moderated by Dr. Joel Sadler, an XR founder and technologist, and Dr. Christoph Leuze of the Stanford Medical Mixed Reality (SMMR) program. Immediately following the panel discussion, you are also invited to a 30-minute interactive session with the panelists where questions and ideas can be explored in real time.

Date and Time: 
Thursday, September 30, 2021 - 9:00am

SCIEN and EE292E presents "Recent developments in GatedVision Imaging -- seeing the unseen""

Topic: 
Recent developments in GatedVision Imaging -- seeing the unseen
Abstract / Description: 

Imaging is the basic building block for automotive autonomous driving. Any computer vision system will require a good image as an input at all driving conditions. GatedVision provides an extra layer on top of the regular RGB/RCCB sensor to augment it at night time and harsh weather conditions. GatedVision images in darkness and different weather conditions will be shared. Imagine that you could detect a small target laying on the road having the same reflectivity as the back ground meaning no contrast, GatedVision can manipulate the way an image is captured so that contrast can be extracted. Additional imaging capabilities of GatedVision will be presented.

Date and Time: 
Wednesday, September 22, 2021 - 10:00am

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SmartGrid

TomKat Center Spring 2021 Innovation Showcase

Topic: 
TomKat Center Spring 2021 Innovation Showcase
Abstract / Description: 

Join us for a one-hour webinar featuring three of our Innovation Transfer teams. They will talk about the sustainable energy problems they are tackling, the technologies underpinning their solutions, and new developments for their products.
April 21, 2021 @ 4pm Pacific

Presentations from:

  • Jayce Hafner and Sami Tellatin, @FarmRaise - The one-stop-shop for farm grants and loans, informed by and built for farmers.
  • Rito Sur, @Indrio Technologies - Laser based sensors for rapid monitoring of chemical concentrations and harmful emissions.
  • Armelle Coutant, @KitSwitch - Adaptive reuse of underutilized commercial buildings into affordable housing.

 


Details and more information on TomKat Center site

 

Date and Time: 
Wednesday, April 21, 2021 - 4:00pm to Thursday, April 22, 2021 - 3:55pm
Venue: 
REGISTRATION REQUIRED

Bits & Watts' Smart Grid Seminar: Electric Grid Security

Topic: 
Electric Grid Security
Abstract / Description: 

Bits & Watts’ Smart Grid Seminar provides experts from academia, startups, research institutes, and large corporations to familiarize seminar participants with current challenges and advances in grid data analytics, economics, market design, battery storage, electrified transportation, power electronics, renewable energy. The seminar is open to Stanford students, as a 1 unit seminar course (CEE 272T/EE292T), and to the broader community.

Date and Time: 
Thursday, May 13, 2021 - 2:30pm

Bits & Watts' Smart Grid Seminar: ERCOT Frequency Regulation Ancillary Services

Topic: 
ERCOT Frequency Regulation Ancillary Services
Abstract / Description: 

Bits & Watts’ Smart Grid Seminar provides experts from academia, startups, research institutes, and large corporations to familiarize seminar participants with current challenges and advances in grid data analytics, economics, market design, battery storage, electrified transportation, power electronics, renewable energy. The seminar is open to Stanford students, as a 1 unit seminar course (CEE 272T/EE292T), and to the broader community.

Date and Time: 
Thursday, April 22, 2021 - 2:30pm

Bits & Watts' Smart Grid Seminar: Large-scale Grid Testbed

Topic: 
Large-scale Grid Testbed
Abstract / Description: 

Bits & Watts' Smart Grid Seminar provides experts from academia, startups, research institutes, and large corporations to familiarize seminar participants with current challenges and advances in grid data analytics, economics, market design, battery storage, electrified transportation, power electronics, renewable energy. The seminar is open to Stanford students, as a 1 unit seminar course (CEE 272T/EE292T), and to the broader community.

Date and Time: 
Thursday, April 15, 2021 - 2:30pm

Smart Grid Seminar: Dynamic Operation and Lifetime Valuation for Batteries in Markets

Topic: 
Dynamic Operation and Lifetime Valuation for Batteries in Markets
Abstract / Description: 

This talk introduces a generalized framework for valuating batteries based on their degradation mechanism and market signals. The proposed framework follows a dynamic programming approach, and novel solution algorithms are designed to accurately model years of battery degradation accumulation, while simulating high granularity optimal control for batteries over time resolutions of minutes or even seconds, including the capability to model stochastic operations. Results from this research will provide pricing and operation references for new and used batteries in grid-interactive applications, and demonstrate how batteries of different degradation mechanisms should be priced differently.

Date and Time: 
Thursday, November 19, 2020 - 1:30pm
Venue: 
Zoom

Smart Grid Seminar: IoT, Smart Microgrid

Topic: 
IoT, Smart Microgrid
Abstract / Description: 

Transforming the grid to a Smart Grid requires real time sensing, of energy producers, consumers, stored capacity in batteries, weather conditions, and more, essential to develop usage models, and anticipate need. Along with the ability to take 'action' such as bringing online cleaner sources of power and curbing demand we can help smooth load peaks. In this talk we introduce the open source project EdgeX Foundry and its viability to deliver a secure, extensible, endpoint to collect real time data, develop models, and control devices. Data processing at the edge while reducing network bandwidth needs, reduces response latency, and helps preserve data privacy. We illustrate this in the context of VMware's on-campus electric vehicle charging facility. We conclude by sharing our longer term goals of developing and controlling hierarchical composite device models and introduce open source project Kinney.

Seminars are open to all Stanford students, faculty, staff and community. Register via the RSVP link

Date and Time: 
Thursday, October 15, 2020 - 1:30pm
Venue: 
Zoom

Smart Grid Seminar: Increasing Electricity Market Efficiency with Flexible Mechanism

Topic: 
Increasing Electricity Market Efficiency with Flexible Mechanism
Abstract / Description: 

Current wholesale electricity market designs of day-ahead and real-time markets have inherent inefficiencies that are amplified with greater shares from intermittent renewable sources. Building in flexibility through time and geographically substitutable bids and stochastic unit commitments can yield significant gains. This talk will discuss how to model and assess these advantages and their implications for renewable generation.

Date and Time: 
Thursday, October 1, 2020 - 1:30pm
Venue: 
Zoom

SmartGrid Seminar presents "Cyber Security Research: A Data Scientist’s Perspective"

Topic: 
Cyber Security Research: A Data Scientist’s Perspective
Abstract / Description: 

Situational awareness of computer networks presents many challenges including but not limited to the volume of the data and the dynamic and evolving nature of the problem space. For example, at the perimeter of a corporate enterprise computer network, it is common to see terabytes of network traffic each day, containing millions of unique IP addresses and connection records that number in the hundreds of millions. Celeste will provide an overview and discuss recent trends facing computer security researchers and practitioners. She will describe recent work at Lawrence Livermore National Laboratory to enable analysis of computer networks and encourage an interactive discussion to foster new ideas to address these challenges.

Date and Time: 
Thursday, May 7, 2020 - 1:30pm
Venue: 
Register at tinyurl.com/Spring-SGS

Smart Grid Seminar presents "California Microgrids: Lessons Learned"

Topic: 
California Microgrids: Lessons Learned
Abstract / Description: 

There has been substantial discussion of the use of microgrids as a result of the recent wildfires and Public Safety Power Shutoffs. The ability of microgrids to be considered for these applications now, is in part a result of over a decade of research funded through the California Energy Commission's R&D programs. To date the CEC has issued over $100M in grants that have funded over 30 microgrids. These microgrids support a variety of applications, with a diversity of ownership models. This presentation will provide an overview of the microgrid research being funded by the CEC and future research areas of interest.

Date and Time: 
Thursday, April 23, 2020 - 1:30pm
Venue: 
Zoom: register to receive ID

Smart Grid Seminar presents "Grid Resilience"

Topic: 
Grid Resilience
Abstract / Description: 

The term "resilience" refers to the ability to prepare for and adapt to changing conditions and withstand and recover rapidly from disruptions. The value of resilience to the electricity system is in enabling the function of other interdependent infrastructure systems and maintaining critical energy-based services. Many resilience approaches are being considered. This webinar will outline some of these perspectives and provide an overview of some of the related ongoing activities within the Department of Energy.

Date and Time: 
Thursday, May 21, 2020 - 1:30pm
Venue: 
Zoom: register to receive ID

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Stanford's NetSeminar

#StanfordToo: A Conversation about Sexual Harassment in Our Academic Spaces

Topic: 
#StanfordToo: A Conversation about Sexual Harassment in Our Academic Spaces
Abstract / Description: 

Individuals of all genders invited to be a part of:
#StanfordToo: A Conversation about Sexual Harassment in Our Academic Spaces, where we will feature real stories of harassment at Stanford academic STEM in a conversation with Provost Drell, Dean Minor (SoM), and Dean Graham (SE3). We will have plenty of time for audience discussion on how we can take concrete action to dismantle this culture and actively work towards a more inclusive Stanford for everyone. While our emphasis is on STEM fields, we welcome and encourage participation from students, postdocs, staff, and faculty of all academic disciplines and backgrounds.

Date and Time: 
Friday, April 19, 2019 - 3:30pm
Venue: 
STLC 111

John G. Linvill Distinguished Seminar on Electronic Systems Technology

Topic: 
Internet of Things and Internet of Energy for Connecting at Any Time and Any Place
Abstract / Description: 

In this presentation, I would like to discuss with you how to establish a sustainable and smart society through the internet of energy for connecting at any time and any place. I suspect that you have heard the phrase, "Internet of Energy" less often. The meaning of this phrase is simple. Because of a ubiquitous energy transmission system, you do not need to worry about a shortage of electric power. One of the most important items for establishing a sustainable society is [...]


"Inaugural Linvill Distinguished Seminar on Electronic Systems Technology," EE News, July 2018

 

Date and Time: 
Monday, January 14, 2019 - 4:30pm
Venue: 
Hewlett 200

Claude E. Shannon's 100th Birthday

Topic: 
Centennial year of the 'Father of the Information Age'
Abstract / Description: 

From UCLA Shannon Centennial Celebration website:

Claude Shannon was an American mathematician, electrical engineer, and cryptographer known as "the father of information theory". Shannon founded information theory and is perhaps equally well known for founding both digital computer and digital circuit design theory. Shannon also laid the foundations of cryptography and did basic work on code breaking and secure telecommunications.

 

Events taking place around the world are listed at IEEE Information Theory Society.

Date and Time: 
Saturday, April 30, 2016 - 12:00pm to Sunday, May 1, 2016 - 11:55am
Venue: 
N/A

NetSeminar

Topic: 
BlindBox: Deep Packet Inspection over Encrypted Traffic
Abstract / Description: 

SIGCOMM 2015, Joint work with: Justine Sherry, Chang Lan, and Sylvia Ratnasamy

Many network middleboxes perform deep packet inspection (DPI), a set of useful tasks which examine packet payloads. These tasks include intrusion detection (IDS), exfiltration detection, and parental filtering. However, a long-standing issue is that once packets are sent over HTTPS, middleboxes can no longer accomplish their tasks because the payloads are encrypted. Hence, one is faced with the choice of only one of two desirable properties: the functionality of middleboxes and the privacy of encryption.

We propose BlindBox, the first system that simultaneously provides both of these properties. The approach of BlindBox is to perform the deep-packet inspection directly on the encrypted traffic. BlindBox realizes this approach through a new protocol and new encryption schemes. We demonstrate that BlindBox enables applications such as IDS, exfiltration detection and parental filtering, and supports real rulesets from both open-source and industrial DPI systems. We implemented BlindBox and showed that it is practical for settings with long-lived HTTPS connections. Moreover, its core encryption scheme is 3-6 orders of magnitude faster than existing relevant cryptographic schemes.

Date and Time: 
Wednesday, November 11, 2015 - 12:15pm to 1:30pm
Venue: 
Packard 202

NetSeminar

Topic: 
Precise localization and high throughput backscatter using WiFi signals
Abstract / Description: 

Indoor localization holds great promise to enable applications like location-based advertising, indoor navigation, inventory monitoring and management. SpotFi is an accurate indoor localization system that can be deployed on commodity WiFi infrastructure. SpotFi only uses information that is already exposed by WiFi chips and does not require any hardware or firmware changes, yet achieves the same accuracy as state-of-the-art localization systems.

We then talk about BackFi, a novel communication system that enables high throughput, long range communication between very low power backscatter IoT sensors and WiFi APs using ambient WiFi transmissions as the excitation signal. We show via prototypes and experiments that it is possible to achieve communication rates of up to 5 Mbps at a range of 1 m and 1 Mbps at a range of 5 meters. Such performance is an order to three orders of magnitude better than the best known prior WiFi backscatter system.

Date and Time: 
Thursday, October 15, 2015 - 12:15pm to 1:30pm
Venue: 
Gates 104

NetSeminar

Topic: 
BlindBox: Deep Packet Inspection over Encrypted Traffic
Abstract / Description: 

SIGCOMM 2015, Joint work with: Justine Sherry, Chang Lan, and Sylvia Ratnasamy

Many network middleboxes perform deep packet inspection (DPI), a set of useful tasks which examine packet payloads. These tasks include intrusion detection (IDS), exfiltration detection, and parental filtering. However, a long-standing issue is that once packets are sent over HTTPS, middleboxes can no longer accomplish their tasks because the payloads are encrypted. Hence, one is faced with the choice of only one of two desirable properties: the functionality of middleboxes and the privacy of encryption.

We propose BlindBox, the first system that simultaneously provides both of these properties. The approach of BlindBox is to perform the deep-packet inspection directly on the encrypted traffic. BlindBox realizes this approach through a new protocol and new encryption schemes. We demonstrate that BlindBox enables applications such as IDS, exfiltration detection and parental filtering, and supports real rulesets from both open-source and industrial DPI systems. We implemented BlindBox and showed that it is practical for settings with long-lived HTTPS connections. Moreover, its core encryption scheme is 3-6 orders of magnitude faster than existing relevant cryptographic schemes.

Date and Time: 
Wednesday, October 7, 2015 - 12:15pm to 1:30pm
Venue: 
AllenX Auditorium

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Statistics and Probability Seminars

Probability Seminar: Probabilistic Littlewood–Offord anti-concentration results via model theory

Topic: 
Probabilistic Littlewood–Offord anti-concentration results via model theory
Abstract / Description: 

The classical Erdos–Littlewood–Offord theorem says that for any n nonzero vectors in R^d, a random signed sum concentrates on any point with probability at most O(n^{1/2}). Combining tools from probability theory, additive combinatorics, and model theory, we obtain an anti-concentration probability of n^{-1/2+o(1)} for any o-minimal set S in R^d — such as a hypersurface defined by a polynomial in x1,...,xn,exp(x1),...,exp(xn), or a restricted analytic function — not containing a line segment. We do this by showing such o-minimal sets have no higher-order additive structure, complementing work by Pila on lower-order additive structures developed to count rational and algebraic points of bounded height.

This is joint work with Jacob Fox and Matthew Kwan.

 

Date and Time: 
Monday, October 25, 2021 - 4:00pm
Venue: 
Sequoia 200

Probability Seminar: Cutoff for the asymmetric riffle shuffle

Topic: 
Cutoff for the asymmetric riffle shuffle
Abstract / Description: 

In the Gilbert–Shannon–Reeds shuffle, a deck of N cards is cut into two approximately equal parts which are riffled together uniformly at random. This Markov chain famously undergoes total variation cutoff after (3/2)*log_2(N) shuffles. We prove cutoff for asymmetric riffle shuffles in which the deck is cut into differently sized parts before riffling, confirming a conjecture of Lalley from 2000.

Date and Time: 
Monday, October 18, 2021 - 4:00pm
Venue: 
Sequoia 200

Probability Seminar: Nonlinear large deviations: Mean-field and beyond

Topic: 
Nonlinear large deviations: Mean-field and beyond
Abstract / Description: 

Large deviations of nonlinear functions of adjacency matrices of sparse random graphs have gained considerable interest over the last decade. This includes popular examples like subgraph count, or the extreme eigenvalues. For the first half of the talk, we will discuss how the upper tail large deviation problem of subgraph count in a random regular graph can be reduced to a variational problem and how to solve such optimization. Next, we consider Erdos–Renyi graph $\mathcal{G}(n,p)$ in the regime of $p$ where largest eigenvalue is governed by localized statistics, such as high degree vertices. In particular, for $r \geq 1$ fixed, we will discuss the upper and lower tail probabilities of top $r$ eigenvalues jointly.

This talk is based on joint works with Bhaswar B. Bhattacharya, Amir Dembo, and Shirshendu Ganguly.

Date and Time: 
Monday, October 11, 2021 - 4:00pm
Venue: 
Sequoia 200

Probability Seminar: Hit and run algorithms and Mallows permutation models with L1 and L2 distances

Topic: 
Hit and run algorithms and Mallows permutation models with L1 and L2 distances
Abstract / Description: 

Introduced by Mallows in statistical ranking theory, Mallows permutation model is a class of non-uniform probability measures on the symmetric group that are biased towards the identity. The general model depends on a distance metric that can be chosen from a host of metrics on permutations. In this talk, I will focus on Mallows permutation models with L1 and L2 distances — respectively known as Spearman's footrule and Spearman's rank correlation in the statistics literature. The models have been widely applied in statistics and physics, but have mostly resisted analysis because the normalizing constants are "uncomputable". In the first part of the talk, I will explain how we can sample from both the L1 and L2 models using hit and run algorithms, which are a unifying class of Markov chain Monte Carlo algorithms that include the celebrated Swendsen–Wang algorithm. A natural question from probabilistic combinatorics is: pick a random permutation from either of the models, what does it "look like"? This may involve various features of the permutation, such as the band structure and the length of the longest increasing subsequence. In the second part of the talk, I will explain how multi-scale analysis and hit and run algorithms can be used to prove theorems regarding such questions.

Date and Time: 
Monday, September 27, 2021 - 4:00pm
Venue: 
Sequoia 200

Workshop in Biostatistics welcomes Moisés Expósito Alonso

Topic: 
"The genomics of climate adaptation and extinction"
Abstract / Description: 

The ongoing climate change has put a spotlight on rapid evolutionary processes that could aid species adapt to new environments. But what is the architecture of fitness across environments? Is this predictable? Can we understand genetic constraints across multiple adaptive traits? How is genetic variation loss during extinction? To address these questions we combine statistical genomics with experimental ecology and genetic engineering approaches using the plant species Arabidopsis thaliana as our experimental climate change genetics model and scaling up insights with publicly available genomes of diverse plant species.

 

Suggested Reading:
● Quantifying the scale of genetic diversity extinction in the Anthropocene
● Natural selection on the Arabidopsis thaliana genome in present and future
climates

Date and Time: 
Thursday, October 21, 2021 - 1:30pm

Workshop in Biostatistics: Big data from tiny microbes across Earth’s ecosystems

Topic: 
Big data from tiny microbes across Earth’s ecosystems
Abstract / Description: 

Genome-resolved metagenomics has enabled unprecedented insights into the ecology and evolution of environmental and host-associated microbiomes. This powerful approach is scalable and was applied to over 10,000 metagenomes collected from diverse habitats to generate an extensive catalog of microbial diversity. In collaboration with a large research consortium, we highlight how this genomic catalog can support discovery of new biosynthetic gene clusters and associating environmental viruses to their microbial hosts.

Date and Time: 
Thursday, September 30, 2021 - 1:30pm

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SystemX

SystemX Seminar: Robots that Work Together, Robots that Play Together

Topic: 
Robots that Work Together, Robots that Play Together
Abstract / Description: 

For robots to effectively operate in our world, they must master the skills of dynamic interaction. Autonomous cars must safely negotiate their trajectories with other vehicles and pedestrians as they drive to their destinations. UAVs must avoid collisions with other aircraft, as well as dynamic obstacles on the ground. Disaster response robots must coordinate to explore and map new disaster sites. In this talk I will describe recent work in my lab using distributed optimization to obtain algorithms for robots to cooperate, and game theoretic methods to obtain algorithms for robots to compete. I will present an algorithm for fleets of autonomous cars to cooperatively track a large number of vehicles and pedestrians in a city, an algorithm for multiple robots to manipulate an object to a goal while avoiding collisions, and a distributed multi-robot SLAM algorithm, all derived using the same underlying distributed optimization framework. I will also discuss algorithms based on the theory of dynamic games, in which each actor has its own objective and constraints. I will describe examples in autonomous drone racing, car racing, and autonomous driving that use game theoretic principles to solve for Nash equilibrium trajectories in real-time, in a receding horizon fashion. Throughout the talk, I will show results from hardware experiments with ground robots, autonomous cars, and quadrotor UAVs collaborating and competing in the scenarios above.

Date and Time: 
Thursday, October 28, 2021 - 5:30pm
Venue: 
Huang 18

SystemX BONUS Seminar: New consumer use cases are shaping the display architectures of tomorrow’s mixed reality headsets and smart glasses

Topic: 
New consumer use cases are shaping the display architectures of tomorrow’s mixed reality headsets and smart glasses
Abstract / Description: 

For the past decade, display and sensor hardware developments for mixed reality and smart glasses were merely a shot in the dark, providing enough display immersion and visual comfort for developers to build up apps, especially for the enterprise field. On the sensor side, emphasis was put on 6DOF head tracking and spatial mapping, gesture sensing and later eye tracking. Today, as universal use cases for consumer emerge such as co-presence, digital twin and remote conferencing, new requirements are expressed in the product requirement documents (PRD) to enable such experiences, both on the display and sensing side. It is not only a race to smaller form factor and light weight devices for large field of view (FOV) and lower power, but the requirements are also on additional display and sensing features specifically tuned to implement such new universal use cases. Broad acceptance of wearable displays especially in the consumer field is contingent on enabling these new display and sensing requirements in small form factors and low power.

Date and Time: 
Tuesday, October 26, 2021 - 2:30pm
Venue: 
Packard 202

SystemX Seminar: Flexible Electronics with Two-Dimensional and Layered Chalcogenide Compounds

Topic: 
Flexible Electronics with Two-Dimensional and Layered Chalcogenide Compounds
Abstract / Description: 

 

As of today, more than 20 billion devices, almost three times the number of people on earth, are connected to the internet. More than half of that are Internet-of-Things (IoT) devices and it is expected that flexible electronics will play a big role in developing new types of IoT sensor systems. Applications include environmental monitoring, food packaging, and biomedical applications like vital sign and disease detection on skin or inside of the human body. However, there are several material, device and integration challenges to solve before flexible IoT systems can become a reality. Most flexible substrates require low process temperature (typically <250 °C), which hinders the direct growth of high-quality semiconductors making the choice of materials limited. At the same time, typical device dimensions are on the micron-scale which leads to low performance and high power consumption. Here, I will show how layered and two-dimensional (2D) chalcogenide compounds can offer attractive solutions for the components needed in flexible electronics overcoming the previously mentioned limitations. I will present our recent work on flexible devices including transistors, sensors, solar cells and memory. In future, combining these devices, we can imagine self-powered flexible IoT systems enabled by low energy consumption and integrated energy harvesters.

Date and Time: 
Thursday, October 21, 2021 - 5:30pm
Venue: 
Huang 018 + Zoom

SystemX presents "High Volume Manufacturing of Silicon Spin Qubits"

Topic: 
High Volume Manufacturing of Silicon Spin Qubits
Abstract / Description: 

High-volume manufacturing of semiconductors has enabled the integrations of billions of transistors on a single chip. Intel leverages this expertise to address engineering challenges in the scale-up of quantum computers. In this talk, we discuss how silicon spin qubits are fabricated in a state-of-the-art CMOS 300 mm fabrication line. The qubits are comparable in size to a transistor, and are highly coherent. Further on, advancements in the measurement infrastructure, such as a 300 mm wafer probing tool operating at 1.6 Kelvin, are shown. Lastly, we will discuss how control electronics operating at cryogenic temperatures can address the interconnect challenge all solid state quantum technologies face.

 

Date and Time: 
Thursday, October 14, 2021 - 5:30pm
Venue: 
Huang 018 + Zoom

SystemX Alliance presents "Scaling photonic quantum computers"

Topic: 
Scaling photonic quantum computers
Abstract / Description: 

Photonics is emerging as one of the leading contenders for building useful quantum computers. I will discuss our recent efforts in building and cloud-deploying photonic quantum computing devices, and our roadmap for scaling up and achieving fault tolerance.

Date and Time: 
Thursday, October 7, 2021 - 5:30pm
Venue: 
Huang 018 + Zoom

SystemX Alliance presents "Aluminum Scandium Nitride Microdevices for Next Generation Nonvolatile Memory and Microelectromechanical Systems"

Topic: 
Aluminum Scandium Nitride Microdevices for Next Generation Nonvolatile Memory and Microelectromechanical Systems
Abstract / Description: 

Aluminum Nitride (AlN) is a well-established thin film piezoelectric material. AlN bulk acoustic wave (BAW) radio frequency (RF) filters were one of the key innovations that enabled the 3G and 4G smart phone revolution. Recently, the substitutional doping of scandium (Sc) for aluminum (Al) to form aluminum scandium nitride (AlScN) has been studied to significantly enhance the piezoelectric properties and to introduce ferroelectric properties into AlN based material systems. The properties achieved have profound implications for the performance of future 5G and 6G RF filters, piezoelectric sensors, piezoelectric energy harvesters, and for scaling the bit density of ferroelectric nonvolatile memories. This talk will present on the synthesis of highly Sc doped AlScN materials of the thickness and quality needed for applications in memory and microelectromechanical systems (MEMS). The material properties achieved will be reported and placed in the context of device specific figures-of-merit and competing material systems. Ferroelectric and electromechanical devices that utilize the unique properties of AlScN to achieve state-of-the-art (SOA) performance will be shown.

Date and Time: 
Tuesday, October 5, 2021 - 2:30pm
Venue: 
Packard 202 + Zoom

SystemX Alliance presents "Digital Wireless in an Analog World"

Topic: 
Digital Wireless in an Analog World
Abstract / Description: 

With plenty of work left to do to realize the vision of 5G, global research community is already working on 6G. Visions of how this system will move us beyond the aggressive objectives of 5G are also accompanied by a list of significant technical challenges. And as 5G and 6G will drive mobile communications deeper into our societal fabric, the technology required spans not only all disciplines within electrical and computer engineering, but also disciplines like social psychology, cognitive and sensory function, and even political science. Coming from the perspective of what it takes to make tools to design and measure such systems, this talk will explore the breadth of opportunity for innovation and contribution.

Date and Time: 
Thursday, September 30, 2021 - 5:30pm
Venue: 
Huang 018 + Zoom

SystemX Alliance presents "Integrated Multi-wavelength Control of Ion Qubits"

Topic: 
Integrated Multi-wavelength Control of Ion Qubits
Abstract / Description: 

Integrating quantum and classical technologies with systems like trapped ions is critical to enable the Moore's law like scaling of qubits necessary to develop practical quantum computers. Recently, we demonstrated operation of an ion-trap chip where integrated photonics delivered all of the required wavelengths, from violet to infrared, necessary for control and read-out of Sr+ qubits[1]. Laser light was coupled onto the chip via an optical-fiber array, creating an inherently stable optical path that we use to demonstrate qubit coherence resilient to platform vibrations. We also explore using multiple zones of interaction to perform parallel qubit operations on multiple ions using parallel integrated beam paths.

[1] Niffenegger, R. J., et al. "Integrated multi-wavelength control of an ion qubit." Nature 586.7830 (2020): 538-542.

Date and Time: 
Thursday, September 23, 2021 - 5:30pm
Venue: 
Huang 018 + Zoom

CANCELLED - SystemX Alliance presents "Autonomous Navigation of Miniature Distributed Space Systems"

Topic: 
Autonomous Navigation of Miniature Distributed Space Systems
Abstract / Description: 

Two key trends are revolutionizing the way humans conduct spaceflight, namely, the miniaturization of satellites (e.g., micro- and nano-satellites) and the distribution of payload tasks among multiple coordinated units (e.g., formation-flying, on-orbit servicing, fractionation, swarms). The combination of these approaches promises breakthroughs in space science (e.g., imaging of earth-like planets, characterization of gravitational waves), remote sensing (e.g., synthetic aperture radar interferometry, aeronomy, gravimetry), and space exploration (e.g., lifetime extension, assembly of structures, space debris removal). Irrespective of the specific application, future miniature distributed space missions require a high level of autonomy to maintain and reconfigure the relative motion of the participating vehicles within the prescribed accuracy and range of operations. Especially on small spacecraft, these requirements are hard to meet due to the limited resources, and the chief goal of current research and development is to pave the way for the autonomous Guidance, Navigation, & Control (GN&C) of "self-driving nanosatellites."

Leveraging the presenter's experience and contributions to recent satellite formation-flying and rendezvous missions in low earth orbit (TanDEM-X, Prisma, Biros), this presentation addresses the navigation algorithms under developments to enable a new class of miniature distributed space instruments (Starling, Visors, Swarm-Ex). The focus will be on autonomous vision-based and radio-frequency spaceborne absolute and relative navigation systems, including their training and validation using high-fidelity hardware-in-the-loop simulations and robotic testbeds at the Stanford's Space Rendezvous Laboratory.

Date and Time: 
Thursday, June 3, 2021 - 4:30pm

SystemX alliance presents "Mixed-Signal Circuits for tinyML Systems"

Topic: 
Mixed-Signal Circuits for tinyML Systems
Abstract / Description: 

Over the past decade, machine learning algorithms have been deployed in many cloud-centric applications. However, as the application space continues to grow, various algorithms are now embedded "closer to the sensor" and in wearable devices, eliminating the latency, privacy and energy penalties associated with cloud access. In this talk, I will review mixed-signal circuit techniques that can improve the energy efficiency of moderate-complexity, low-power machine learning inference algorithms. Specific examples include analog feature extraction for image and audio processing, as well as mixed-signal compute circuits for convolutional neural networks.

Date and Time: 
Thursday, May 27, 2021 - 4:30pm

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