## EE Student Information

#### EE Student Information, Spring Quarter 19-20: FAQs and Updated EE Course List.

Updates will be posted on this page, as well as emailed to the EE student mail list.

As always, use your best judgement and consider your own and others' well-being at all times.

# Seminar / Colloquium

## Smart Grid Seminar presents "Cyber Security Roadmap and Challenge"

Topic:
Abstract / Description:

Cyber security has become a critical priority for electric utilities, which are increasingly dependent on information technology and telecommunication infrastructure to ensure the reliability and security of the electric grid. Additionally, rapid, disruptive changes are happening in electric grids around the world. In many states and countries, initiatives are underway to integrate small, renewable generation into the distribution grid, to meet the local demand for electricity, while reducing the dependency on large, central generation facilities and long-distance transmission. This transition requires new technologies, connectivity, and intelligence, which inherently changes the attack surface of the grid and introduces new stakeholders in the delivery and use of power. This talk provides an introduction to these new cyber security issues, discusses EPRI's approach to addressing the challenges, and presents future research opportunities.

Date and Time:
Thursday, May 28, 2020 - 1:30pm
Venue:

## Smart Grid Seminar presents "Dynamic Electricity Pricing"

Topic:
Dynamic Electricity Pricing
Abstract / Description:

With the rapid growth in residential smart meters across the United States in recent years, most homes will soon be capable of moving to time varying prices for electricity. We discuss a methodology for studying the welfare impacts of different pricing strategies on an electricity market when homes deploy smart, price responsive appliances with forward-looking capabilities, and understanding its effects on social welfare and consumer surplus. We show conditions under which asymptotically, as the number of homes increases, social welfare-maximizing price schedules in equilibrium are linear in load. Real data are used to calibrate a smart thermostat model to compare dynamic pricing strategy against flat and peak pricing strategies when smart thermostats are deployed across ComEd's service territory of 3.5 million residential homes.

Date and Time:
Thursday, May 14, 2020 - 1:30pm
Venue:

## Probability Seminar presents "Speeding up Markov chains with deterministic jumps"

Topic:
Speeding up Markov chains with deterministic jumps
Abstract / Description:

A striking example of the phenomenon: Consider simple random walk on the integers mod n [X(k+1)] = X(k) + epsilon(k+1)(mod n) where epsilon takes values {0,1,-1} with probability 1/3 each. This walk takes order n2 steps to get random. Now make a slight modification: X(k+1) = 2X(k) + epsilon(k+1) (mod n). This has the same amount of randomness BUT, for almost all n, the walk gets random in order log(n) steps.

In joint work with Sourav Chatterjee we show this as quite a general phenomenon. For any doubly stochastic Markov chain on n states and any permutation f(x) on the state space, the walk that goes from x to f(x) to y, where y is one step of the chain, mixes in order log (n) states for almost all permutations f. Since it happens for most f, this raises the problem of finding specific f for real problems. Some progress will be reported.

Date and Time:
Monday, April 27, 2020 - 4:00pm

## Probability Seminar presents "Distribution of descents (and other permutation statistics) in conjugacy classes of S_n"

Topic:
Distribution of descents (and other permutation statistics) in conjugacy classes of S_n
Abstract / Description:

The distribution of descents in Sn, the symmetric group, have been previously studied. This talk starts with a bijective proof (using tableaux) of the symmetry of the descents and major indices in matchings (fixed point free involutions) and uses a generating function approach to prove a central theorem for descents in matchings. This approach will be extended to prove central limit theorems for descents in all conjugacy classes of Sn, and to other permutation statistics, such as peaks and major indices.

This is joint work with Sangchul Lee (UCLA) and should be accessible to all graduate students.

Date and Time:
Monday, April 20, 2020 - 4:00pm
Venue:
Meeting ID 98027417672

## Stanford Institute for Theoretical Physics seminar

Topic:
TBA
Abstract / Description:

Abstract TBA - speaker and event details are subject to change.

Date and Time:
Monday, May 11, 2020 - 2:00pm
Venue:
Zoom ID: 165 492 015

## Stanford Institute for Theoretical Physics presents "Continuum Quantum Field Theories for Fractons"

Topic:
Continuum Quantum Field Theories for Fractons
Abstract / Description:

Starting with a lattice system at short distances, its long-distance behavior is captured by a continuum Quantum Field Theory (QFT). This description is universal, i.e. it is independent of most of the details of the microscopic system. Surprisingly, certain recently discovered lattice systems, and in particular models of fractons, seem to violate this general dogma. Motivated by this apparent contradiction, we will present exotic continuum QFTs that describe these systems.

Date and Time:
Monday, April 27, 2020 - 2:00pm
Venue:
Zoom ID: 165 492 015

## Stanford Institute for Theoretical Physics presents "Replica wormhole and information retrieval in the SYK model coupled to Majorana chains"

Topic:
Replica wormhole and information retrieval in the SYK model coupled to Majorana chains
Abstract / Description:

Motivated by recent studies of the information paradox in (1+1)-D anti-de Sitter spacetime with a bath described by a (1+1)-D conformal field theory, we study the dynamics of second Rényi entropy of the Sachdev-Ye-Kitaev (SYK) model (χ) coupled to a Majorana chain bath (ψ). The system is prepared in the thermofield double (TFD) state and then evolved by HL+HR. For small system-bath coupling, we find that the second Rényi entropy S(2)χL,χR of the SYK model undergoes a first order transition during the evolution. In the sense of holographic duality, the long-time solution corresponds to a "replica wormhole". The transition time corresponds to the Page time of a black hole coupled to a thermal bath. We further study the information scrambling and retrieval by introducing a classical control bit, which controls whether or not we add a perturbation in the SYK system. The mutual information between the bath and the control bit shows a positive jump at the Page time, indicating that the entanglement wedge of the bath includes an island in the holographic bulk.

Date and Time:
Monday, April 20, 2020 - 2:00pm
Venue:
Zoom id: 165-492-015

## SystemX presents "Astrobee ISS Free Flyers: Overview and Enabling Technologies"

Topic:
Astrobee ISS Free Flyers: Overview and Enabling Technologies
Abstract / Description:

The Astrobee robots began operations on the International Space Station (ISS) in April of 2019. These 32-cm-wide, 9-kg, cube-shaped free flyers are capable of autonomously traversing the US Orbital Segment of ISS and performing tasks to assist astronauts in their day-to-day activities. The Astrobee Facility also provides an on-orbit testbed for guest scientists desiring to try new technologies in zero-g. This presentation will provide an overview of the Astrobee system and some of its key enabling technologies, including propulsion, navigation, and human interfaces. Additional information and publications can be found on the Astrobee website: nasa.gov/astrobee.

Date and Time:
Thursday, April 23, 2020 - 4:30pm
Venue:
Zoom

## SystemX presents "On-chip LIDAR with inverse design"

Topic:
On-chip LIDAR with inverse design
Abstract / Description:

LIDAR can provide detailed spatial maps of an environment, a capability that is essential for applica- tions such as autonomous driving, robotics, building modeling, or augmented reality. Bulky optical elements and moving parts in current LIDAR systems have unfortunately made these systems heavy, expensive, and vibration-sensitive. Solid-state optical devices for the functionalities required for a LIDAR system have therefore driven much integrated photonics research in recent years. For on-chip beam-steering, optical phased arrays (OPAs) have emerged as a promising solution; however, the size and efficiency specifications for an effective LIDAR-OPA design have remained challenging for classical photonics design methods. In this talk, I will present how photonic inverse design methods can improve OPA design. Unlike classical photonic design, inverse design allows for arbitrary device geometries through the use of advanced elec- tromagnetic optimization methods. The extra degrees of freedom these methods provide has resulted in numerous new photonic devices with improved efficiency, reduced on-chip footprint or novel functionali- ties. Leveraging these new capabilities, we demonstrate an OPA design with a larger scanning cone and a smaller operating bandwidth as compared to the classical photonic design solutions.

Date and Time:
Thursday, April 16, 2020 - 4:30pm
Venue:
Zoom

## Stanford Institute for Theoretical Physics presents "On the Entropy of an Einstein-Rosen Bridge"

Topic:
On the Entropy of an Einstein-Rosen Bridge
Abstract / Description:

We propose a new link between entropy and area: an eternal black hole with an ER bridge with cross-section A can carry quantum information, or be in a mixed state, with entropy S ≤ A/4GN . We provide evidence for our proposal in the context of AdS3 and JT gravity, by using the Island prescription and replica wormhole method for computing the Renyi entropy. We argue that a typical two sided black hole is described by a 'thermo-mixed double' state with only classical correlations between the two sides. Our reasoning suggests that an ER wormhole acts like a topological quantum memory, similar to the toric code.

Zoom id: 165-492-015 (Please note that this is a recurring id, valid till May 11.)

Date and Time:
Monday, April 13, 2020 - 2:00pm
Venue:
Zoom

## Applied Physics/Physics Colloquium presents "New roles for wormholes"

Topic:
New roles for wormholes
Abstract / Description:

A powerful idea in theoretical physics is the conjecture that (from a distance) black holes behave like ordinary quantum systems. Thought of in this way, black holes display many deep quantum phenomena in simple but often surprising ways. We will discuss recent work (involving wormholes) that gives new examples of this and also uncovers new puzzles.

Date and Time:
Tuesday, May 5, 2020 - 4:30pm
Venue:
Zoom Meeting ID: 954 8449 2474

## 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
Venue:
Hansen Physics & Astrophysics Building, 102/103

## Applied Physics/Physics Colloquium: Quantum Optical Control of Levitated Solids: a novel probe for the gravity-quantum interface

Topic:
Quantum Optical Control of Levitated Solids: a novel probe for the gravity-quantum interface
Abstract / Description:

The increasing level of control over motional quantum states of massive, solid-state mechanical devices opens the door to a hitherto unexplored parameter regime of macroscopic quantum physics. I will report on our recent progress towards controlling levitated solids in the quantum regime. I will discuss the prospects of using these systems for fundamental tests of physics, including the interface between quantum and gravitational physics.

Winter Qtr. Colloq. committee: M. Schleier-Smith (Chair), B. Cabrera, S. Dimopoulos, T. Heinz, S. Kachru & L. Tompkins
Location: Hewlett Teaching Center, Rm. 200

Date and Time:
Tuesday, March 3, 2020 - 4:30pm
Venue:
Hewlett 200

## Applied Physics/Physics Colloquium presents "Dark Matter halos from parametric resonance and their signatures"

Topic:
Dark Matter halos from parametric resonance and their signatures
Abstract / Description:

While there is undisputed evidence for Dark Matter, its nature and properties remain one of the biggest questions of our time. What is Dark Matter (DM)? How is it produced? Does it have interactions other than gravitational? In this talk, I will describe how a large class of bosonic particles can account for the DM of the Cosmos. These particles can be much lighter than those of the Standard Model with Compton wavelengths that are bigger than the size of our solar system or smaller than a millimeter. In the presence of attractive self-interactions, there is a parametric resonance effect in the early universe that can cause growth of structure at small scales, an effect so dramatic that can cause structures to collapse well before matter-radiation equality. The signatures of this effect span several experiments and orders of magnitude in parameter space. When the DM boson is heavy, the dense DM halos can alter the optimal search strategies in direct detection experiments. When the DM boson is light, these halos may leave their imprint in searches for dark matter substructure, primordial gravitational waves and alter the star formation history of the universe.

Winter Qtr. Colloq. committee: M. Schleier-Smith (Chair), B. Cabrera, S. Dimopoulos, T. Heinz, S. Kachru & L. Tompkins
Location: Hewlett Teaching Center, Rm. 200

Date and Time:
Tuesday, February 25, 2020 - 4:30pm
Venue:
Hewlett 200

## Applied Physics/Physics Colloquium presents "Fracton – elasticity duality"

Topic:
Fracton – elasticity duality
Abstract / Description:

I will discuss a recent discovery that elasticity theory of a two-dimensional quantum crystal is dual to a fracton tensor and to a coupled-vector gauge theories, thereby providing a concrete realization of the so-called "fracton quantum order". The disclinations and dislocations respectively map onto charges and dipoles of these gauge theories. The fractionalized mobility of fractons matches the constrained dynamics of crystal's topological defects. These dualities lead to predictions of fractonic phases, and phase transitions to their descendants, that are duals of the commensurate crystal, supersolid, smectic, and hexatic liquid crystals. Extensions of this duality to generalized elasticity theories provide a route to discovery of new fractonic models and their potential experimental realizations.

Winter Qtr. Colloq. committee: M. Schleier-Smith (Chair), B. Cabrera, S. Dimopoulos, T. Heinz, S. Kachru & L. Tompkins
Location: Hewlett Teaching Center, Rm. 200

Date and Time:
Tuesday, February 18, 2020 - 4:30pm
Venue:
Hewlett 200

## Applied Physics/Physics Colloquium presents "Quantum Science with Tweezer Arrays"

Topic:
Quantum Science with Tweezer Arrays
Abstract / Description:

Recently cold atoms in optical tweezer arrays have emerged as a versatile platform for quantum science experiments. I will review some of these developments, specifically, atom-by-atom assembly [1] as a fast and simple method to generate defect-free atomic arrays and Rydberg-based quantum simulation of spin models. While already reaching competitive results, these systems are still in their infancy and limitations in coherence, detection fidelity, and scalability remain. I will outline how we can improve on these issues and open new avenues in quantum metrology by using alkaline earth atoms, followed by an overview of recent results: 1) A record in imaging-fidelity for neutral atoms and demonstration of narrow-line cooling in tweezers [2,3]. 2) High-fidelity Rydberg excitation from a clock state, including a record in entanglement-fidelity for two neutral atoms [4]. 3) Demonstration of an optical clock with single-atom detection in tweezer arrays [5].

[1] Endres et al., Science 354, 1024 (2016)

[2] Covey et. al, Phys. Rev. Lett. 122, 173201 (2019)

[3] Cooper et al., Phys. Rev. X 8, 041055 (2018)

[4] Madjarov*, Covey*, et al., arXiv:2001.04455 (2020)

[5] Madjarov et al., Phys. Rev. X 9, 041052 (2019)

Winter Qtr. Colloq. committee: M. Schleier-Smith (Chair), B. Cabrera, S. Dimopoulos, T. Heinz, S. Kachru & L. Tompkins
Location: Hewlett Teaching Center, Rm. 200

Date and Time:
Tuesday, February 11, 2020 - 4:30pm
Venue:
Hewlett 200

## Applied Physics/Physics Colloquium presents "Quantum Physics from a computational complexity angle"

Topic:
Quantum Physics from a computational complexity angle
Abstract / Description:

Quantum computation is just around the corner, maybe; or it may take a few decades to see the true technological revolution it offers. Who knows.

In any case, the field had already reshaped the way we think of quantum physics. Computational complexity notions such as quantum NP and interactive proofs shed light on old physics questions such as relaxation times and the nature of entanglement in ground states; as well as on how we understand what a quantum measurement really is. I will provide some examples of recent lines of research in quantum computation, which demonstrate how this blending of the computational complexity language into the heart of quantum physics can lead to some interesting new insights and questions.

Winter Qtr. Colloq. committee: M. Schleier-Smith (Chair), B. Cabrera, S. Dimopoulos, T. Heinz, S. Kachru & L. Tompkins
Location: Hewlett Teaching Center, Rm. 200

Date and Time:
Tuesday, February 4, 2020 - 4:30pm
Venue:
Hewlett 200

## Applied Physics/Physics Colloquium presents "Twisty fun in 2D materials"

Topic:
Twisty fun in 2D materials
Abstract / Description:

A van der Waals bonded solid consists of sheets of two-dimensional (2D) atomic layers with strong bonding in-plane. When these crystals are grown naturally, the stacking order along the out-of-plane dimension is dictated by the van der Waals force, typically leading to all layers of the crystal being oriented in the same in-plane direction. Recently, it has become possible to synthetically create materials where the individual layers have arbitrary in-plane direction relative to each other. These materials are of great interest theoretically since they realize new crystal structures not achievable in nature, with new emergent properties predicted. One of the key experimental findings in one such material last year was the presence of superconductivity and Mott insulating behavior in twisted bilayer graphene, properties that the individual layers do not display by themselves. In this talk, I will describe STM and transport properties of three such materials: (a) twisted bilayer graphene, where we measure the electronic structure of the material that is a Mott insulator (b) twisted bilayer WSe2, where we also observe Mott insulating behavior and (c) twisted double bilayer graphene, where we have evidence from STM for excitonic insulator behavior as well as the presence of chiral topological edge states in the interior of the material.

Winter Qtr. Colloq. committee: M. Schleier-Smith (Chair), B. Cabrera, S. Dimopoulos, T. Heinz, S. Kachru & L. Tompkins
Location: Hewlett Teaching Center, Rm. 200

Date and Time:
Tuesday, January 28, 2020 - 4:30pm
Venue:
Hewlett 200

## Applied Physics/Physics Colloquium presents "Space Observatories of the Highest Energy Particles: POEMMA & EUSO-SPB"

Topic:
Space Observatories of the Highest Energy Particles: POEMMA & EUSO-SPB
Abstract / Description:

#### What are the mysterious sources of the most energetic particles ever observed? What are the sources of energetic cosmic neutrinos? How do particles interact at extreme energies?

Building on the progress achieved by the ground-based Auger Observatory in studying cosmic particles that reach 100 EeV, an international collaboration is working on space and sub-orbital missions to answer these questions. The Extreme Universe Space Observatory (EUSO) on a super pressure balloon (SPB) is designed to detect ultra-high energy cosmic rays (UHECRs) from above. EUSO-SPB1 flew in 2017 with a fluorescence telescope. EUSO-SPB2 is being built to observe both fluorescence and Cherenkov from UHECRs and neutrinos. These sub-orbital missions lead to POEMMA, the Probe Of Extreme Multi-Messenger Astrophysics, a space mission designed to discover the sources of UHECRs and to observe neutrinos above 20 PeV from energetic transient events. POEMMA will open new Multi-Messenger windows onto the most energetic events in the Universe, enabling the study of new astrophysics and particle physics at these otherwise inaccessible energies

Winter Qtr. Colloq. committee: M. Schleier-Smith (Chair), B. Cabrera, S. Dimopoulos, T. Heinz, S. Kachru & L. Tompkins
Location: Hewlett Teaching Center, Rm. 200

Date and Time:
Tuesday, January 21, 2020 - 4:30pm
Venue:
Hewlett 200

## Applied Physics/Physics Colloquium presents "Quantum oscillations in solids: past, present and future"

Topic:
Quantum oscillations in solids: past, present and future
Abstract / Description:

On a visit to Stanford to honor Ted Geballe's centennial, I think it is appropriate to talk about an aspect of condensed matter and materials physics that has spanned his entire professional lifetime. The de Haas – van Alphen effect is one of the most profound and pronounced manifestations of quantum mechanics in solids. Discovered in Leiden fully ninety years ago as a signal in the magnetic torque of bismuth, the effect is now observed in a huge range of physical properties, and often given the general name of 'quantum oscillations'. The quest from discovery to full understanding required seminal contributions from some of the most celebrated names of twentieth century physics, such as Landau, Onsager and Lifshitz. The true hero of the technique, perhaps less well known than the above friends and colleagues with whom he collaborated, was the Cambridge-based Russian experimental physicist David Shoenberg. I had the privilege of knowing David for the last ten years of his life, and of learning about quantum oscillations from him and from his protégé Gil Lonzarich. In this talk I will review the historical development of the field, and try to show how important it has been, as a driver for the development of low temperature-low noise experimental techniques, for the growth of high purity single crystals, and for the introduction of key concepts in the theory of solids. I will close by stressing that the party is far from over. New physics associated with the de Haas – van Alphen effect still at the forefront of condensed matter science to this day, and there is an ongoing search for even more exotic relatives that are predicted to exist in certain special many-body systems.

Winter Qtr. Colloq. committee: M. Schleier-Smith (Chair), B. Cabrera, S. Dimopoulos, T. Heinz, S. Kachru & L. Tompkins
Location: Hewlett Teaching Center, Rm. 200

Date and Time:
Tuesday, January 14, 2020 - 4:30pm
Venue:
Hewlett 200

## CS300 Seminar

Topic:
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
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
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 6:00pm
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 6:00pm
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 6:00pm
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 6:00pm
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 6:00pm
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 6:00pm
Venue:
200-305 Lane History Corner, Main Quad

## 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
Venue:

## 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:
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

## EE380 Computer Systems Colloquium presents "Lenia: Biology of Artificial Life"

Topic:
Lenia: Biology of Artificial Life
Abstract / Description:

In the field of Artificial Life, we use biochemistry, engineering and computer simulation to answer "what is life" and "what life could be". Starting from Conway's Game of Life, a famous discrete cell simulation, we tried to make everything smooth and continuous, and then something strange emerged. In this new system called "Lenia", we discovered lots of self-organizing, self-regulating dynamic patterns, look and behave much like microscopic life seen in biology class or plankton videos. More than just being amused, we investigated these creatures in details, performed computer experiments, classification, statistical analysis, and probed into the nature of such dynamic and complex system. We see possible links between Lenia, biological life, and artificial intelligence.

Date and Time:
Wednesday, January 15, 2020 - 4:30pm
Venue:
Shriram 104

## 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.

Date and Time:
Wednesday, May 6, 2020 - 1:00pm
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

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

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
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

## AP 483 Seminar Series presents "Non-Hermitian Photonics: Optics at an Exceptional Point"

Topic:
Non-Hermitian Photonics: Optics at an Exceptional Point
Abstract / Description:

In recent years, non-Hermitian degeneracies, also known as exceptional points (EPs), have emerged as a new paradigm for engineering the response of optical systems. At such points, an N-dimensional space can be represented by a single eigenvalue and one eigenvector. As a result, these points are associated with abrupt phase transitions in parameter space. Among many different non-conservative photonic configurations, parity-time (PT) symmetric systems are of particular interest since they provide a powerful platform to explore, and consequently utilize, the physics of exceptional points in a systematic manner. In this talk, I will review some of our recent works in the area of non-Hermitian (mainly PT-symmetric) active photonics. For example, in a series of works, we have demonstrated how the generation and judicial utilization of these points in laser systems can result in unexpected dynamics, unusual linewidth behavior, and improved modal response. On the other hand, biasing a photonic system at an exceptional point can lead to orders of magnitude enhancement in sensitivity, an effect that may enable a new generation of ultrasensitive optical sensors on-chip. Non-Hermiticity can also be used as a means to promote or single out an edge mode in photonic topological insulator lattices. Rotation sensors play a crucial role in a diverse set of applications associated with navigation, positioning, and inertial sensing. Most optical gyroscopes rely on the Sagnac effect induced phase shift that scales linearly with the rotational velocity. In ring laser gyroscopes (RLGs), this shift manifests itself as a resonance splitting in the emission spectrum that can be detected as a beat frequency. The need for evermore precise RLGs has fueled research activities towards devising new approaches aimed to boost the sensitivity beyond what is dictated by geometrical constraints. In this respect, attempts have been made in the past to use either dispersive or nonlinear effects. Here, we propose a new scheme for ultrasensitive laser gyroscopes that utilizes the physics of exceptional points. By exploiting the properties of such non- Hermitian degeneracies, we show that the rotation-induced frequency splitting becomes proportional to the square root of the gyration speed, thus enhancing the sensitivity to low angular rotations by orders of magnitudes. We will then describe a possible modification of a standard RLG to support an exceptional point and measure the resulting enhanced sensitivity in the proposed system.

Date and Time:
Monday, January 27, 2020 - 4:15pm
Venue:
Spilker 232

## AP 483 Seminar Series presents "Where Are We Heading: A Brief History and Future of Navigation"

Topic:
Abstract / Description:

- tba -

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

Date and Time:
Monday, January 13, 2020 - 4:15pm
Venue:
Spilker 232

## ISL Colloquium presents "Federated Learning at Google and Beyond"

Topic:
Federated Learning at Google and Beyond
Abstract / Description:

Federated Learning enables mobile devices to collaboratively learn a shared prediction model or analytic while keeping all the training data on device, decoupling the ability to do machine learning from the need to store the data in the cloud. It embodies the principles of focused collection and data minimization, and can mitigate many of the systemic privacy risks and costs resulting from traditional, centralized machine learning. In this talk, I will discuss: (1) how federated learning differs from more traditional distributed machine learning paradigms, focusing on the main defining characteristics and challenges of the federated learning setting; (2) practical algorithms for federated learning that address the unique challenges of this setting; (3) extensions to federated learning, including differential privacy, secure aggregation, and compression for model updates, and (4) a range of valuable research directions that could have significant real-world impact.

Date and Time:
Friday, February 28, 2020 - 1:15pm
Venue:
Packard 202

## RL forum presents "Temporal Abstraction in Reinforcement Learning with the Successor Representation"

Topic:
Temporal Abstraction in Reinforcement Learning with the Successor Representation
Abstract / Description:

Reasoning at multiple levels of temporal abstraction is one of the key abilities for artificial intelligence. In the reinforcement learning problem, this is often instantiated with the options framework. Options allow agents to make predictions and to operate at different levels of abstraction within an environment. Nevertheless, when a reasonable set of options is not known beforehand, there are no definitive answers for characterizing which options one should consider. Recently, a new paradigm for option discovery has been introduced. This paradigm is based on the successor representation (SR), which defines state generalization in terms of how similar successor states are. In this talk I'll discuss the existing methods from this paradigm, providing a big picture look at how the SR can be used in the options framework. I'll present methods for discovering "bottleneck" options, as well as options that improve an agent's exploration capabilities. I'll also discuss the option keyboard, which uses the SR to extend a finite set of options to a combinatorially large counterpart without additional learning.

Date and Time:
Tuesday, February 25, 2020 - 2:00pm
Venue:
Packard 202

## ISL Colloquium presents "Fully Convolutional Pixelwise Context-Adaptive Denoiser"

Topic:
Abstract / Description:

Denoising is a classical problem in signal processing and information theory, and various different methods have been applied to tackle the problem for several decades. Recently, supervised-trained neural network-based methods have achieved impressive denoising performances, significantly surpassing those of the classical approaches, such as prior- or optimization-based denoisers. However, there are two drawbacks on those methods; they are not adaptive, i.e., the neural- network cannot correct itself when distributional mismatch between training and test data exists, and they require clean source data and exact noise model for training, which is not always possible in some practical scenarios. In this talk, I will introduce a framework that tries to tackle above two drawbacks jointly, based on an unbiased estimate of the loss of a particular class of pixelwise context- adaptive denoisers. Using the framework and neural networks to learn the denoisers, I show the resulting image denoiser can adapt to mismatched distributions in the data solely based on the given noisy images, and achieve the state-of-the-art performances on several benchmark datasets. Moreover, combined with the standard noise transform/estimation techniques, I will show that our denoiser can be completely blindly trained only with the noisy images (and without exact noise model) and yet be very effective for denoising more sophisticated, source-dependent real-world noise, e.g., Poisson- Gaussian noise.

This is a joint work with my students, Sungmin Cha and Jaeseok Byun at SKKU.

Date and Time:
Friday, February 21, 2020 - 1:15pm
Venue:
Packard 202

## ISL & IT-Forum present "Approaching Capacity at Short Blocklengths"

Topic:
Approaching Capacity at Short Blockengths
Abstract / Description:

This talk explores a family of recent results directed to approaching capacity at short blocklengths on the order of 50-500 channel transmissions. Convolutional codes out-perform polar codes and LDPC codes to approach the random coding union bound with low complexity when used with an optimized CRCs and list decoding. This perspective rehabilitates "catastrophic" convolutional codes, which are more properly understood for finite blocklengths as clever expurgation rather than any sort of catastrophe. This approach also provides a low-complexity approach for maximum-likelihood decoding of high-rate BCH codes. The use of variable length coding, i.e. incremental redundancy controlled with simple ACK/NACK feedback, allows capacity to be closely approached by practical codes with fewer than 500 channel uses. This talk reviews the information-theoretic results of Polyanskiy with respect to ACK/NACK feedback, presents new results extending the classic approach of Horstein for full feedback, and shows how to optimize the number and length of incremental redundancy transmissions (and feedback transmissions) for a variable-length code with feedback (i.e. a type-II hybrid ARQ). The talk also shows how to avoid entirely the overhead of a CRC in a hybrid ARQ setting by directly computing the reliability of convolutional codeword decisions. Finally, attendees will learn about a novel communications architecture that allows the use of incremental redundancy even without feedback.

Date and Time:
Friday, January 24, 2020 - 1:15pm
Venue:
Packard 202

Topic:
Abstract / Description:

Compressive imaging enables faster acquisitions by capturing coded projections of the scenes. Codification elements used in compressive imaging systems include lithographic masks, gratings and micro-polarizers, which sense spatial, spectral, and temporal data. Codification plays a key role in compressive imaging as it determines the number of projections needed for correct reconstruction. In general, random coding patterns are sufficient for accurate reconstruction. Still, more recent studies have shown that code design not only yields to improved image reconstructions, but it can also reduce the number of required projections. This talk covers different tools for codification design in compressive imaging, such as the restricted isometry property, geometric and deep learning approaches. Applications in compressive spectral video, compressive X-ray computed tomography, and seismic acquisition will be also discussed.

The Information Systems Laboratory Colloquium (ISLC) is typically held in Packard 101 every Thursday at 4:30 pm during the academic year. Coffee and refreshments are served at 4pm in the second floor kitchen of Packard Bldg.

The Colloquium is organized by graduate students Joachim Neu, Tavor Baharav and Kabir Chandrasekher. To suggest speakers, please contact any of the students.

Date and Time:
Thursday, March 5, 2020 - 4:30pm
Venue:
Packard 101

## ISL Colloquium presents "Empirical Risk Minimization in High-dimensions: Asymptotics, Optimality and Double Descent"

Topic:
Empirical Risk Minimization in High-dimensions: Asymptotics, Optimality and Double Descent
Abstract / Description:

At the heart of contemporary statistical signal processing problems, as well as modern machine-learning practices, lie high-dimensional inference tasks in which the number of unknown parameters is of the same order as (and often larger than) the number of observations.

In this talk, I describe a framework based on Gaussian-process inequalities to sharply characterize the statistical performance of convex empirical risk minimization in high dimensions. By focusing on the simple, yet highly versatile, model of binary linear classification, I will demonstrate that, albeit challenging, sharp results are advantageous over loose order-wise bounds. For instance, they lead to precise answers to the following questions: When are training data linearly separable? Is least-squares bad for binary classification? What is the best convex loss function? Is double descent observed in linear models and how do its features (such as the transition threshold and global minima) depend on the training data and on the learning procedure?

Many of the ideas and technical tools of our work originate from the study of sharp phase-transitions in compressed sensing. Throughout the talk, I will highlight how our results relate to and advance this literature.

The Information Systems Laboratory Colloquium (ISLC) is typically held in Packard 101 every Thursday at 4:30 pm during the academic year. Coffee and refreshments are served at 4pm in the second floor kitchen of Packard Bldg.

The Colloquium is organized by graduate students Joachim Neu, Tavor Baharav and Kabir Chandrasekher. To suggest speakers, please contact any of the students.

Date and Time:
Thursday, February 27, 2020 - 4:30pm
Venue:
Packard 101

## ISL Colloquium presents "Network Systems, Kuramoto Oscillators, and Synchronous Power Flow"

Topic:
Network Systems, Kuramoto Oscillators, and Synchronous Power Flow
Abstract / Description:

Network systems are mathematical models for the study of cooperation, propagation, synchronization and other dynamical phenomena that arise among interconnected agents. Network systems are widespread in science and technology as fundamental modeling tools.

This talk will review established and emerging frameworks for modeling, analysis and design of network systems. Next, I will focus on recent developments on the analysis of security and transmission capacity in power grids. I will review the Kuramoto model of coupled oscillators and present recent results on its synchronization behavior. I will also review recent results on multi-stability and multistable synchronous power flows.

The Information Systems Laboratory Colloquium (ISLC) is typically held in Packard 101 every Thursday at 4:30 pm during the academic year. Coffee and refreshments are served at 4pm in the second floor kitchen of Packard Bldg.

The Colloquium is organized by graduate students Joachim Neu, Tavor Baharav and Kabir Chandrasekher. To suggest speakers, please contact any of the students.

Date and Time:
Thursday, February 20, 2020 - 4:30pm
Venue:
Packard 101

## ISL Colloquium presents "Recurrent Switching Linear Dynamical Systems for Neural and Behavioral Analysis"

Topic:
Recurrent Switching Linear Dynamical Systems for Neural and Behavioral Analysis
Abstract / Description:

The trend in neural recording capabilities is clear: we can record orders of magnitude more neurons now than we could only a few years ago, and technological advances do not seem to be slowing. Coupled with rich behavioral measurements, genetic sequencing, and connectomics, these datasets offer unprecedented opportunities to learn how neural circuits function. But they also pose serious modeling and algorithmic challenges. We need flexible yet interpretable probabilistic models to gain insight from these heterogeneous data and algorithms to efficiently and reliably fit them. I will present some recent work on recurrent switching linear dynamical systems (rSLDS) — models that couple discrete and continuous latent states to model nonlinear processes. I will discuss some approximate Bayesian inference algorithms we've developed to fit these models and infer their latent states, and I will show how these methods can help us gain insight into complex spatiotemporal datasets like those we study in neuroscience.

The Information Systems Laboratory Colloquium (ISLC) is typically held in Packard 101 every Thursday at 4:30 pm during the academic year. Coffee and refreshments are served at 4pm in the second floor kitchen of Packard Bldg.

The Colloquium is organized by graduate students Joachim Neu, Tavor Baharav and Kabir Chandrasekher. To suggest speakers, please contact any of the students.

Date and Time:
Thursday, February 13, 2020 - 4:30pm
Venue:
Packard 101

## ISL Colloquium presents "How to trap a gradient flow"

Topic:
How to trap a gradient flow
Abstract / Description:

I will discuss a new strategy to find stationary points of non-convex functions in low-dimensional spaces. In particular we resolve an open problem from 1993 by Stephen A. Vavasis on the complexity of this problem in 2D.

Joint work with Dan Mikulincer.

The Information Systems Laboratory Colloquium (ISLC) is typically held in Packard 101 every Thursday at 4:30 pm during the academic year. Coffee and refreshments are served at 4pm in the second floor kitchen of Packard Bldg.

The Colloquium is organized by graduate students Joachim Neu, Tavor Baharav and Kabir Chandrasekher. To suggest speakers, please contact any of the students.

Date and Time:
Thursday, February 6, 2020 - 4:30pm
Venue:
Packard 101

## ISL Colloquium presents "From Feedforward-Designed Convolutional Neural Networks (FF-CNNs) to Successive Subspace Learning (SSL)"

Topic:
From Feedforward-Designed Convolutional Neural Networks (FF-CNNs) to Successive Subspace Learning (SSL)
Abstract / Description:

Given a convolutional neural network (CNN) architecture, its network parameters are typically determined by backpropagation (BP). The underlying mechanism remains to be a black-box after a large amount of theoretical investigation. In this talk, I will first describe a new interpretable feedforward (FF) design with the LeNet-5 as an example. The FF-designed CNN is a data-centric approach that derives network parameters based on training data statistics layer by layer in a one-pass feedforward manner. To build the convolutional layers, we develop a new signal transform, called the Saab (Subspace approximation with adjusted bias) transform. The bias in filter weights is chosen to annihilate nonlinearity of the activation function. To build the fully-connected (FC) layers, we adopt a label-guided linear least squared regression (LSR) method. To generalize the FF design idea furthermore, we present the notion of "successive subspace learning (SSL)" and present a couple of concrete methods for image and point cloud classification. Experimental results are given to demonstrate the competitive performance of the SSL-based systems. Similarities and differences between SSL and deep learning (DL) are compared.

The Information Systems Laboratory Colloquium (ISLC) is typically held in Packard 101 every Thursday at 4:30 pm during the academic year. Coffee and refreshments are served at 4pm in the second floor kitchen of Packard Bldg.

The Colloquium is organized by graduate students Joachim Neu, Tavor Baharav and Kabir Chandrasekher. To suggest speakers, please contact any of the students.

Date and Time:
Thursday, January 30, 2020 - 4:30pm
Venue:
Packard 101

## IT Forum presents "Fundamental barriers to estimation in high-dimensions"

Topic:
Fundamental barriers to estimation in high-dimensions
Abstract / Description:

Modern large-scale statistical models require to estimate thousands to millions of parameters. Understanding the tradeoff between statistical optimality and computational tractability in such models remains an outstanding challenge. Under a random design assumption, we establish lower bounds to statistical estimation with two popular classes of tractable estimators in several popular statistical models. First, in high-dimensional linear models we show that a large gap often exists between the optimal statistical error and that achieved by least squares with a convex penalty. Examples of such estimators include the Lasso, ridge regression, and MAP estimation with log-concave priors and Gaussian noise. Second, in generalized linear models and low-rank matrix estimation problems, we introduce the class of 'general first order methods,' examples of which include gradient descent, projected gradient descent, and their accelerated versions. We derive lower bounds for general first order methods which are tight up to asymptotically negligible terms. Our results demonstrate a gap to statistical optimality for general first order methods in both sparse phase retrieval and sparse PCA.

This is joint work with Andrea Montanari and Yuchen Wu.

Date and Time:
Friday, April 3, 2020 - 1:15pm
Venue:
Zoom: stanford.zoom.us/j/516499996

## IT Forum presents "What Hockey Teams and Foraging Animals Can Teach Us About Feedback Communication"

Topic:
What Hockey Teams and Foraging Animals Can Teach Us About Feedback Communication
Abstract / Description:

Suppose we wish to communicate over a memoryless channel with known statistics. How can the use of a feedback link from the receiver to the transmitter help? We introduce a novel mechanism for using feedback, called timid/bold coding, and we show that for some channels timid/bold coding yields a strict asymptotic improvement over the best non- feedback schemes. We also show that for a broad class of channels, feedback is useful if and only if timid/bold coding is applicable. The talk contains a puzzle (recently featured on the FiveThirtyEight website), a life lesson, a (potential) practical application, and some stochastic calculus.

This is joint work with Nirmal Shende and Yucel Altug.

Date and Time:
Friday, March 6, 2020 - 1:15pm
Venue:
Packard 202

## RL forum presents "Temporal Abstraction in Reinforcement Learning with the Successor Representation"

Topic:
Temporal Abstraction in Reinforcement Learning with the Successor Representation
Abstract / Description:

Reasoning at multiple levels of temporal abstraction is one of the key abilities for artificial intelligence. In the reinforcement learning problem, this is often instantiated with the options framework. Options allow agents to make predictions and to operate at different levels of abstraction within an environment. Nevertheless, when a reasonable set of options is not known beforehand, there are no definitive answers for characterizing which options one should consider. Recently, a new paradigm for option discovery has been introduced. This paradigm is based on the successor representation (SR), which defines state generalization in terms of how similar successor states are. In this talk I'll discuss the existing methods from this paradigm, providing a big picture look at how the SR can be used in the options framework. I'll present methods for discovering "bottleneck" options, as well as options that improve an agent's exploration capabilities. I'll also discuss the option keyboard, which uses the SR to extend a finite set of options to a combinatorially large counterpart without additional learning.

Date and Time:
Tuesday, February 25, 2020 - 2:00pm
Venue:
Packard 202

## IT Forum presents "Why should information theorists and probabilists care about blockchains?"

Topic:
Why should information theorists and probabilists care about blockchains?
Abstract / Description:

The invention of blockchains in 2008 opened up for the first time the possibility of large scale decentralized trust systems. In the past few years, the design and analysis of blockchains have received significant attention from cryptography, security and distributed systems communities. In this talk, I argue that there are many interesting problems for information theorists and probabilists as well. I will discuss two particular classes of problems: 1) security analysis of blockchains as convergence analysis of random tree processes; 2) the use of coding to efficiently scale blockchains. I will also briefly discuss a course I plan to teach in the Spring on the topic.

Part of this talk is on joint work with Amir Dembo and Ofer Zeitouni.

Date and Time:
Friday, January 31, 2020 - 1:00pm
Venue:
Packard 202

## 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
Venue:
Hansen Physics & Astrophysics Building, 102/103

## ISL & IT-Forum present "Approaching Capacity at Short Blocklengths"

Topic:
Approaching Capacity at Short Blockengths
Abstract / Description:

This talk explores a family of recent results directed to approaching capacity at short blocklengths on the order of 50-500 channel transmissions. Convolutional codes out-perform polar codes and LDPC codes to approach the random coding union bound with low complexity when used with an optimized CRCs and list decoding. This perspective rehabilitates "catastrophic" convolutional codes, which are more properly understood for finite blocklengths as clever expurgation rather than any sort of catastrophe. This approach also provides a low-complexity approach for maximum-likelihood decoding of high-rate BCH codes. The use of variable length coding, i.e. incremental redundancy controlled with simple ACK/NACK feedback, allows capacity to be closely approached by practical codes with fewer than 500 channel uses. This talk reviews the information-theoretic results of Polyanskiy with respect to ACK/NACK feedback, presents new results extending the classic approach of Horstein for full feedback, and shows how to optimize the number and length of incremental redundancy transmissions (and feedback transmissions) for a variable-length code with feedback (i.e. a type-II hybrid ARQ). The talk also shows how to avoid entirely the overhead of a CRC in a hybrid ARQ setting by directly computing the reliability of convolutional codeword decisions. Finally, attendees will learn about a novel communications architecture that allows the use of incremental redundancy even without feedback.

Date and Time:
Friday, January 24, 2020 - 1:15pm
Venue:
Packard 202

## ISL Colloquium presents "Self-Programming Networks: Applications to Financial Trading Systems"

Topic:
Self-Programming Networks: Applications to Financial Trading Systems
Abstract / Description:

We describe Self-Programming Networks (SPNs), an ongoing research effort at Stanford for making cloud computing networks autonomous; that is, to enable the networks to sense and monitor themselves, and program and control themselves. We describe the goals and the architecture of SPNs and present two key outcomes: (i) Huygens, for scalable and accurate clock synchronization, and (ii) Simon, for fine-grained network telemetry using observations from the network’s edge. We also describe the relevance of this work to existing financial trading systems and demonstrate how, in future, it enables financial trading systems in the Cloud.

The Information Systems Laboratory Colloquium (ISLC) is typically held in Packard 101 every Thursday at 4:30 pm during the academic year. Coffee and refreshments are served at 4pm in the second floor kitchen of Packard Bldg.

The Colloquium is organized by graduate students Joachim Neu, Tavor Baharav and Kabir Chandrasekher. To suggest speakers, please contact any of the students.

Date and Time:
Thursday, January 23, 2020 - 4:30pm
Venue:
Packard 101

## ISL & IT Forum present "Higher Criticism for discriminating frequency-tables and testing authorship"

Topic:
Higher Criticism for discriminating frequency-tables and testing authorship
Abstract / Description:

The Higher Criticism (HC) test is a useful tool for detecting the presence of a signal spread across a vast number of features, especially in the sparse setting when only few features are useful while the rest contain only noise. We adapt the HC test to the two-sample setting of detecting changes between two frequency tables. We apply this adaptation to authorship attribution challenges, where the goal is to identify the author of a document using other documents whose authorship is known. The method is simple yet performs well without handcrafting and tuning. Furthermore, as an inherent side effect, the HC calculation identifies a subset of discriminating words, which allow additional interpretation of the results. Our examples include authorship in the Federalist Papers and machine-generated texts.

We take two approaches to analyze the success of our method. First, we show that, in practice, the discriminating words identified by the test: have low variance across documents belonging to a corpus of homogeneous authorship. We conclude that in testing a new document against the corpus of an author, HC is mostly affected by words characteristic of that author and is relatively unaffected by topic structure. Finally, we analyze the power of the test in discriminating two multinomial distributions under sparse and weak perturbations model. We show that our test has maximal power in a wide range of the model parameters, even though these parameters are unknown to the user.

Date and Time:
Friday, January 10, 2020 - 1:15pm
Venue:
Packard 202

## ISL Colloquium and IT-Forum present "A Notion of Entropy for Sparse Marked Graphs and its Applications in Graphical Data Compression"

Topic:
A Notion of Entropy for Sparse Marked Graphs and its Applications in Graphical Data Compression
Abstract / Description:

Many modern data sources arising from social networks, biological data, etc. are best viewed as indexed by combinatorial structures such as graphs, rather than time series. The local weak limit theory for sparse graphs, also known as the objective method, due to Benjamini, Schramm, Aldous, Steele, Lyons and others, provides a framework which enables one to make sense of a stationary process indexed by graphs. The theory of time series is the engine driving an enormous range of applications in areas such as control theory, communications, information theory and signal processing. It is to be expected that a theory of stationary stochastic processes indexed by combinatorial structures, in particular graphs, would eventually have a similarly wide-ranging impact.

Employing the above framework, we introduce a notion of entropy for probability distributions on rooted graphs. This is a generalization of the notion of entropy introduced by Bordenave and Caputo to graphs which carry marks on their vertices and edges. Such marks can represent information on real-world data. For instance, in a social network graph where each node represents an individual and edges represent friendships, a vertex mark represents the type of an individual, while edge marks represent shared data between friends. The above notion of entropy can be considered as a natural counterpart for the Shannon entropy rate in the world of graphical data. We illustrate this by introducing a universal compression scheme for marked graphical data. Furthermore, we introduce an algorithm that can perform such a compression with low complexity.

This talk is based on joint work with Venkat Anantharam.

Date and Time:
Friday, December 6, 2019 - 1:15pm
Venue:
Packard 202

## ISL & IT Forum present "An information-theoretic solution to random access communication"

Topic:
An information-theoretic solution to random access communication
Abstract / Description:

The emergence of networks of many devices in the context of cyber-physical systems underscores the need for novel solutions for communication over random access channels. Most protocols currently in place rely on collision avoidance and are woefully ill-suited to handling high variation in the number and variety of communicators. We ask the question of whether it is possible, in a scenario where no one knows how many transmitters are active, for the receiver to almost always recover the messages sent by all active transmitters. Surprisingly, we find that not only is reliable decoding possible in this regime, but it is possible to attain both the capacity and the dispersion of the multiple access channel in operation. Our strategy relies on ''semi-rateless'' codes: decoding attempts are made at a sparse set of pre-determined decoding times, and the decoder is tasked with recovering from the channel output the messages of the active transmitters. Once the decoder determines that reliable decoding can be made, a positive acknowledgement (ACK) is sent to the encoders, indicating the end of that communication epoch and the start of a new one. The feedback ensures that the collection of active transmitters remains fixed during each epoch. These semi-rateless codes work for both channel and source coding; for source coding, our semi-rateless scheme achieves the optimal performance up to the first three order terms in the Gaussian approximation of the optimal rate. The analysis includes a refinement of the random coding argument ensuring the existence of a deterministic code that meets multiple constraints simultaneously, a random-coding union achievability bound for multiple access, and a sharp converse bound for multiple access source coding via a connection to composite hypothesis testing.

Based on joint works (ArXiv:1801.09018, ArXiv:1902.03366) with M. Effros, R. C. Yavas, S. Chen.

Date and Time:
Friday, November 22, 2019 - 1:15pm
Venue:
Packard 202

## OSA/SPIE, SPRC and Ginzton Lab present "Workshop on Inverse Design using SPINS"

Topic:
Workshop on Inverse Design using SPINS
Abstract / Description:

The goal of this workshop is to provide attendees with a practitioner's perspective of the basic ingredients and tools of inverse design using SPINS [1], a photonic optimization framework developed at Jelena Vuckovic's Nanoscale and Quantum Photonics Lab over the past decade.
SPINS is a flexible inverse-design platform that is compatible with a variety of device parametrizations, electromagnetic solvers, and objective functions. This has enabled SPINS to be used to design and experimentally demonstrate functional devices in a wide variety of different application areas including grating couplers [2-4], optical routing for LiDAR [5], and electron accelerators [6].
In this workshop, we will work through examples of using SPINS to design simple devices, including grating couplers and silicon photonics devices. We will emphasize how attendees can adapt these examples for their own applications and discuss some practical considerations for using inverse-design to produce functional devices. All example code will be available online after the workshop.

[1] Su, L. et al. Nanophotonic inverse design with SPINS: software architecture and practical considerations. Appl. Phys. Rev. https://doi.org/10.1063/1.5131263 (2020).
[2] Su, L. et al. Fully-automated optimization of grating couplers. Optics Express, 26(4): 4023–4034, 2018.
[3] Sapra, N. V. et al. Inverse design and demonstration of broadband grating couplers. IEEE J. Sel. Top. Quantum Electron. 25, 1–7 (2019).
[4] Dory, etl al. Inverse-designed diamond photonics. Nature Communications, 10(1):3309, 2019.
[5] Yang, K. Skarda, J. et al., Inverse-designed non-reciprocal pulse router for chip-based LiDAR, Nature Photonics DOI: 10.1038/s41566-020-0606-0 (2020)
[6] Sapra, N. V. et al., On-chip integrated laser-driven particle accelerator. Science 367, 79-83 (2020).

Date and Time:
Thursday, June 4, 2020 - 1:30pm
Venue:
Zoom ID: 945 5728 7546 (password required)

## 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.

Date and Time:
Wednesday, May 6, 2020 - 1:00pm
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)

## Stanford Photonics Research Center (SPRC) SPECIAL SEMINAR on Global Environmental Measurement and Monitoring Technologies

Topic:
The Source and Fate of Fossil Fuel CO2 Emissions
Abstract / Description:

Fossil fuel burning is the primary driver of increasing atmospheric carbon dioxide (CO2), which recently passed the landmark 400 parts per million mark. Most nations have committed to reducing their emissions under the Paris Agreement and many sub-national entities have made similar commitments. To ensure that the promised emission reductions are achieved, an understanding of emission rates from fossil fuel point sources, cities, regions and countries, and of uptake of carbon into the land and oceans, is critical.

Traditionally, "bottom-up" economic information has been used to determine fossil fuel emission rates, and biomass estimates are used to evaluate the land carbon sink. In this presentation, I will discuss the use of a "top-down" approach that uses atmospheric measurements and modelling that complements the bottom-up method. In particular, I will focus on the use of radiocarbon (14C) in CO2 as a tracer for the fossil fuel component of atmospheric CO2. I will showcase how the method can be used to quantify fossil fuel CO2 emissions and land carbon uptake, giving examples from USA and New Zealand.

Date and Time:
Thursday, March 12, 2020 - 3:30pm
Venue:
Spilker 232

## 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

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

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

## OSA/SPIE present "A revolution in high-performance computing driven by CMOS-integrated photonics"

Topic:
A revolution in high-performance computing driven by CMOS-integrated photonics
Abstract / Description:

Recent years have seen an explosive growth in bandwidth requirements at all levels of computing, from consumer-grade GPUs to datacenters and supercomputers. Consensus is growing that traditional interconnect development is reaching its limits. Electrical I/O is limited to line data rates of around 112 Gbps, given physical limits of copper and dielectrics losses, and noise. Proposed approaches to surpass this limit increasingly offer higher rates without providing any real benefit; bandwidth comes with degradation of power consumption, complexity, and cost. Furthermore, the 112 Gbps limit is achievable only over very short distances, constraining the architecture of computer systems.

Photonic I/O is the only viable, near-term path to increasing data rates, and to solving the problems of power consumption, bandwidth, and latency faced by electrical I/O. Its low latency and low propagation loss can enable new "disaggregated" computer architectures, with separate chips of memory and logic linked over larger distances for more efficient utilization.

Ayar labs is pursuing a photonic interconnect solution that involves an external multi-wavelength laser source, an integrated transceiver chip with photonics densely integrated along with CMOS circuits, along with advanced chip packaging and optical-fiber connectivity. The transceiver chip integrates electro-optic modulators and detectors with analog drivers, control logic, and SERDES, taking advantage of dense integration to reduce parasitics, power consumption, latency, and packaging costs. Micro-rings provide wavelength-division multiplexing of many channels needed to achieve high capacity per chip edge at low power consumption. This development comes at an exciting time: the emergence of a large-scale process for CMOS-compatible photonics along with and advanced packaging ecosystem is converging with an acute market need for bandwidth density.

Date and Time:
Tuesday, February 11, 2020 - 4:15pm
Venue:
Allen 101X

## Special MSE Colloquium presents "Spatiotemporal Metaphotonics"

Topic:
Spatiotemporal Metaphotonics
Abstract / Description:

Materials are often used to manipulate waves. Metamaterials have provided far-reaching possibilities in achieving "extremes" in such wave-matter interaction. Various exciting functionalities have been achieved in exploiting metamaterials and metasurfaces in nanophotonics and nano-optics. We have been exploring how spatiotemporal metamaterials can give us new platforms in metaphotonics for exploiting waves to do certain useful functions for us. Several scenarios are being investigated in my group. As one scenario, we have been developing metastructure platforms that can perform analog computation such as solving integral and differential equations and inverting matrices with waves as waves interact with them. Such "metamaterial machines" can function as wave-based analog computing machines, suitable for micro- and nanoscale integration. Another scenario deals with 4-dimensional metamaterials, in which temporal variation of material parameters is added to the tools of spatial inhomogeneities for manipulating light-matter interaction with spatiotemporal platforms. The third category for metaphotonics is the concept of near-zero-index materials, structures and associated photonic doping that exhibit unique features in light-matter interaction, opening doors to exciting new wave-based and quantum optical features. In this talk, I will present some of our ongoing work on extreme and spatiotemporal material platforms for metaphotonics, and will forecast possible future research directions in these paradigms.

Date and Time:
Tuesday, February 4, 2020 - 3:00pm
Venue:
Durand 450

## 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
Venue:
Hansen Physics & Astrophysics Building, 102/103

## SCIEN Talk

Topic:
Abstract / Description:

Compressive imaging enables faster acquisitions by capturing coded projections of the scenes. Codification elements used in compressive imaging systems include lithographic masks, gratings and micro-polarizers, which sense spatial, spectral, and temporal data. Codification plays a key role in compressive imaging as it determines the number of projections needed for correct reconstruction. In general, random coding patterns are sufficient for accurate reconstruction. Still, more recent studies have shown that code design not only yields to improved image reconstructions, but it can also reduce the number of required projections. This talk covers different tools for codification design in compressive imaging, such as the restricted isometry property, geometric and deep learning approaches. Applications in compressive spectral video, compressive X-ray computed tomography, and seismic acquisition will be also discussed.

Date and Time:
Wednesday, June 3, 2020 - 4:30pm
Venue:
Zoom (join SCIEN mail list to receive meeting ID)

## SCIEN presents "Mojo Lens, the First True Smart Contact Lens"

Topic:
Mojo Lens, the First True Smart Contact Lens
Abstract / Description:

After working in stealth for over 4 years, Mojo Vision recently unveiled the first working prototype of Mojo Lens, a smart contact lens designed to deliver augmented reality content wherever you look. This talk will provide an overview of the company, its vision of "Invisible Computing", the science behind the world's first contact lens display, and a first-hand account of what it's like to actually wear Mojo Lens.

Date and Time:
Wednesday, May 27, 2020 - 4:30pm
Venue:
Zoom (join SCIEN mail list to receive meeting ID)

## SCIEN presents "Learned Image Synthesis for Computational Displays"

Topic:
Learned Image Synthesis for Computational Displays
Abstract / Description:

Addressing vergence-accommodation conflict in head-mounted displays (HMDs) requires resolving two interrelated problems. First, the hardware must support viewing sharp imagery over the full accommodation range of the user. Second, HMDs should accurately reproduce retinal defocus blur to correctly drive accommodation. A multitude of accommodation-supporting HMDs have been proposed, with three architectures receiving particular attention: varifocal, multifocal, and light field displays. These designs all extend depth of focus, but rely on computationally expensive rendering and optimization algorithms to reproduce accurate defocus blur (often limiting content complexity and interactive applications). To date, no unified framework has been proposed to support driving these emerging HMDs using commodity content. In this talk, we will present DeepFocus, a generic, end-to-end convolutional neural network designed to efficiently solve the full range of computational tasks for accommodation-supporting HMDs. This network is demonstrated to accurately synthesize defocus blur, focal stacks, multilayer decompositions, and multiview imagery using only commonly available RGB-D images, enabling real-time, near-correct depictions of retinal blur with a broad set of accommodation-supporting HMDs.

Date and Time:
Wednesday, May 20, 2020 - 4:30pm
Venue:
Zoom (join SCIEN mail list to receive meeting ID)

## SCIEN presents Practical 2D to 3D Image Conversion

Topic:
Practical 2D to 3D Image Conversion
Abstract / Description:

We will discuss techniques for converting 2D images to 3D meshes on mobile devices. This includes methods to efficiently compute both dense and sparse depth maps, converting depth maps into 3D meshes, mesh inpainting, and post-processing. We focus on different CNN designs to solve each step in the processing pipeline and examine common failure modes. Finally, we will look at practical deployment of image processing algorithms and CNNs on mobile apps, and how Lucid uses cloud processing to balance processing power with latency.

Date and Time:
Wednesday, May 13, 2020 - 4:30pm
Venue:
Zoom (join SCIEN mail list to receive meeting ID)

## SCIEN Seminar presents "Bio-inspired depth sensing using computational optics"

Topic:
Bio-inspired depth sensing using computational optics
Abstract / Description:

Jumping spiders rely on accurate depth perception for predation and navigation. They accomplish depth perception, despite their tiny brains, by using specialized optics. Each principal eye includes a multitiered retina that simultaneously receives multiple images with different amounts of defocus, and distance is decoded from these images with seemingly little computation. In this talk, I will introduce two depth sensors that are inspired by jumping spiders. They use computational optics and build upon previous depth-from-defocus algorithms in computer vision. Both sensors operate without active illumination, and they are both monocular and computationally efficient.
The first sensor synchronizes an oscillating deformable lens with a photosensor. It produces depth and confidence maps at more than 100 frames per second and has the advantage of being able to extend its working range through optical accommodation. The second sensor uses a custom-designed metalens, which is an ultra-thin device with 2D nano-structures that modulate traversing light. The metalens splits incoming light and simultaneously forms two differently-defocused images on a planar photosensor, allowing the efficient computation of depth and confidence from a single snapshot in time.

Date and Time:
Wednesday, May 6, 2020 - 4:30pm
Venue:
Zoom (join SCIEN mail list to receive meeting ID)

## SCIEN Seminar presents "Insight into the inner workings of Intel’s Stereo and Lidar Depth Cameras"

Topic:
Insight into the inner workings of Intel’s Stereo and Lidar Depth Cameras
Abstract / Description:

This talk will provide an overview of the technology and capabilities of Intel's RealSense Stereo and Lidar Depth Cameras, and will then progress to describe new features, such as high-speed capture, multi-camera enhancements, optical filtering, and near-range high-resolution depth imaging. Finally, we will introduce a new fast on-chip calibration method that can be used to improve the performance of a stereo camera and help mitigate some common stereo artifacts.

Date and Time:
Wednesday, April 29, 2020 - 4:30pm
Venue:
Zoom (join SCIEN mail list to receive meeting ID)

## SCIEN Seminar presents "The Extreme Science of Building High-Performing Compact Cameras for Space Applications"

Topic:
The Extreme Science of Building High-Performing Compact Cameras for Space Applications
Abstract / Description:

A thickening flock of earth-observing satellites blankets the planet. Over 700 were launched during the past 10 years, and more than 2,200 additional ones are scheduled to go up within the next 10 years. To add to that, year on year, satellite platforms and instruments are being miniaturized to improve cost-efficiency with the same expectations of high spatial and spectral resolutions. But what does it take to build imaging systems that are high-performing in the harsh environment of space but cost-efficient and compact at the same time? This talk will touch upon the technical issues associated with the design, fabrication, and characterisation of such extremely high-performing but still compact and cost-efficient space cameras taking the example of the imager that Pixxel has built as part of its earth-imaging satellite constellations plans.

Date and Time:
Wednesday, April 22, 2020 - 4:30pm
Venue:
Zoom (join SCIEN mail list to receive meeting ID)

## SCIEN Seminar presents "The Role of Fundamental Limits in 3D Imaging Systems: From Looking around Corners to Fast 3D Cameras"

Topic:
The Role of Fundamental Limits in 3D Imaging Systems: From Looking around Corners to Fast 3D Cameras
Abstract / Description:

The knowledge about limits is a precious commodity in computational imaging: By knowing that our imaging device already operates at the physical limit (e.g. of resolution), we can avoid unnecessary investments in better hardware, such as faster detectors, better optics or cameras with higher pixel resolution. Moreover, limits often appear as uncertainty products, making it possible to bargain with nature for a better measurement by sacrificing less important information.

In this talk, the role of physical and information limits in computational imaging will be discussed using examples from two of my recent projects: 'Synthetic Wavelength Holography' and the 'Single-Shot 3D Movie Camera'.

Synthetic Wavelength Holography is a novel method to image hidden objects around corners and through scattering media. While other approaches rely on time-of-flight detectors, which suffer from technical limitations in spatial and temporal resolution, Synthetic Wavelength Holography works at the physical limit of the space-bandwidth product. Full field measurements of hidden objects around corners or through scatterers reaching sub-mm resolution will be presented.

The single-shot 3D movie camera is a highly precise 3D sensor for the measurement of fast macroscopic live scenes. From each 1 Mpix camera frame, the sensor delivers 300,000 independent 3D points with high resolution. The single-shot ability allows for a continuous 3D measurement of fast moving or deforming objects, resulting in a continuous 3D movie. Like a hologram, each movie-frame encompasses the full 3D information about the object surface, and the observation perspective can be varied while watching the 3D movie.

Date and Time:
Wednesday, April 15, 2020 - 4:30pm
Venue:
Zoom (join SCIEN mail list to receive meeting ID)

## SCIEN Seminar presents "Image recovery with untrained convolutional neural networks"

Topic:
Image recovery with untrained convolutional neural networks
Abstract / Description:

Convolutional Neural Networks are highly successful tools for image recovery and restoration. A major contributing factor to this success is that convolutional networks impose strong prior assumptions about natural images—so strong that they enable image recovery without any training data. A surprising observation that highlights those prior assumptions is that one can remove noise from a corrupted natural image by simply fitting (via gradient descent) a randomly initialized, over-parameterized convolutional generator to the noisy image.
In this talk, we discuss a simple un-trained convolutional network, called the deep decoder, that provably enables image denoising and regularization of inverse problems such as compressive sensing with excellent performance. We formally characterize the dynamics of fitting this convolutional network to a noisy signal and to an under-sampled signal, and show that in both cases early-stopped gradient descent provably recovers the clean signal. Finally, we discuss our own numerical results and numerical results from another group demonstrating that un-trained convolutional networks enable magnetic resonance imaging from highly under-sampled measurements.

Date and Time:
Wednesday, April 8, 2020 - 4:30pm
Venue:
Zoom (join SCIEN mail list to receive meeting ID)

## SCIEN and EE292E present "An Integrated 6DoF Video Camera and System Design"

Topic:
An Integrated 6DoF Video Camera and System Design
Abstract / Description:

Designing a fully integrated 360◦ video camera supporting 6DoF head motion parallax requires overcoming many technical hurdles, including camera placement, optical design, sensor resolution, system calibration, real-time video capture, depth reconstruction, and real-time novel view synthesis. While there is a large body of work describing various system components, such as multi-view depth estimation, our paper is the first to describe a complete, reproducible system that considers the challenges arising when designing, building, and deploying a full end-to-end 6DoF video camera and playback environment. Our system includes a computational imaging software pipeline supporting online markerless calibration, high-quality reconstruction, and real-time streaming and rendering. Most of our exposition is based on a professional 16-camera configuration, which will be commercially available to film producers. However, our software pipeline is generic and can handle a variety of camera geometries and configurations. The entire calibration and reconstruction software pipeline along with example datasets is open sourced to encourage follow-up research in high-quality 6DoF video reconstruction and rendering.

Date and Time:
Wednesday, March 4, 2020 - 4:30pm
Venue:
Packard 101

## 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 ## Smart Grid Seminar presents "Cyber Security Roadmap and Challenge" Topic: Cyber Security Roadmap and Challenge Abstract / Description: Cyber security has become a critical priority for electric utilities, which are increasingly dependent on information technology and telecommunication infrastructure to ensure the reliability and security of the electric grid. Additionally, rapid, disruptive changes are happening in electric grids around the world. In many states and countries, initiatives are underway to integrate small, renewable generation into the distribution grid, to meet the local demand for electricity, while reducing the dependency on large, central generation facilities and long-distance transmission. This transition requires new technologies, connectivity, and intelligence, which inherently changes the attack surface of the grid and introduces new stakeholders in the delivery and use of power. This talk provides an introduction to these new cyber security issues, discusses EPRI's approach to addressing the challenges, and presents future research opportunities. Date and Time: Thursday, May 28, 2020 - 1:30pm Venue: Zoom: register to receive ID ## Smart Grid Seminar presents "Dynamic Electricity Pricing" Topic: Dynamic Electricity Pricing Abstract / Description: With the rapid growth in residential smart meters across the United States in recent years, most homes will soon be capable of moving to time varying prices for electricity. We discuss a methodology for studying the welfare impacts of different pricing strategies on an electricity market when homes deploy smart, price responsive appliances with forward-looking capabilities, and understanding its effects on social welfare and consumer surplus. We show conditions under which asymptotically, as the number of homes increases, social welfare-maximizing price schedules in equilibrium are linear in load. Real data are used to calibrate a smart thermostat model to compare dynamic pricing strategy against flat and peak pricing strategies when smart thermostats are deployed across ComEd's service territory of 3.5 million residential homes. Date and Time: Thursday, May 14, 2020 - 1:30pm Venue: Zoom: register to receive ID ## Opportunities in Solar Research and Entrepreneurship Topic: Opportunities in Solar Research and Entrepreneurship Abstract / Description: Renewable energy generation, storage and energy efficiency are being rapidly integrated into our digitized buildings, transportation system and electric grid. Exponentially expanding opportunities for entrepreneurs to commercialize new products are blossoming. This talk will highlight examples of the wide-ranging resources available to help start-up initiatives accelerate cycles of learning and bring innovations to market. Some specific resources to be reviewed include: • Stanford's TomKat Center for Sustainable Energy Innovation Transfer • The NSF I-Corps Program adapted from Steve Blank's Stanford Lean LaunchPad class • The Elemental Accelerator in East Palo Alto • Emily Kirsch's PowerHouse Incubator and PowerHouse Ventures in Oakland • Cyclotron Road at Lawrence Berkeley National Laboratory • The National Renewable Energy Laboratory Industry Growth Forum and Innovation Incubator • The Department of Energy Solar Prize • Dorothy Jones-Davis' Nation of Makers • The American-Made Partner Network Date and Time: Thursday, April 23, 2020 - 2:30pm Venue: Zoom ## Bits and Watts presents "Battery Electric Vehicles, Energy Management, and the Smart Grid: An OEM Perspective" Topic: Battery Electric Vehicles, Energy Management, and the Smart Grid: An OEM Perspective Abstract / Description: Ford is pursuing an aggressive electrification of their product portfolio that includes the launch of the all-electric 2021 Mustang Mach-E, all-electric F-150, and all-electric global commercial van. With 100 kWh of electrical capacity, and potentially more, on board, Ford customers will have enough energy to meet their daily driving needs. However, what if there is more than enough energy? Ford is looking closely at how battery electric vehicles can unlock additional value for customers in a world of a dynamic and intelligent electrical energy system. This talk will briefly cover Ford's electrification strategy and the mission of Greenfield Labs, Ford's Silicon Valley outpost. It will review projects on connected charging infrastructure and hands-free charging and describe the ways that Ford researchers are envisioning smart vehicles in a smart world. Date and Time: Thursday, February 27, 2020 - 1:30pm Venue: Shriram 104 ## Bits and Watts presents "Towards Transactive Energy: A Common Experimentation with EDF, SMUD, OMEGA Grid and ENEDIS" Topic: Towards Transactive Energy: A Common Experimentation with EDF, SMUD, OMEGA Grid and ENEDIS Abstract / Description: EDF (Électricité de France), Sacramento Municipal Utility district (SMUD) and Omega Grid are partnering to test Transactive Energy. We are creating a blockchain-based local electricity market, based on OG's software, to coordinate electric vehicle (EV) charging with solar generation. This local energy market project will demonstrate the use of blockchain technology to coordinate EV charging with local solar generation and wholesale prices in a blockchain-based incentive program. The program will show how distribution utilities can use a blockchain-based local energy market to add millions of new solar panels, EVs, and batteries to their grids without expensive infrastructure upgrades. The local energy market demonstration will take place near Sacramento, California, and receive support from the EDF Innovation Laboratory team based in Silicon Valley. The project is backed in part by an APPA grant. Date and Time: Thursday, February 13, 2020 - 1:30pm Venue: Shriram 104 ## SmartGrid Seminar presents "Intelligent Protection Schemes for Renewable Energy Integration" Topic: Intelligent Protection Schemes for Renewable Energy Integration Abstract / Description: By 2050, the costs of an average PV and wind plant are expected to fall by 71% and 58%, respectively. Meanwhile, batteries will further depress market prices, which in turn enable the deeper penetration of renewable energies like PV, wind, and electric vehicles (EVs). However, the transition on primary energy resources can be a double-edged sword. Problems such as protective relay is landing and fault detection, protective relay coordination under environmental uncertainty, topology recovery of secondary distribution networks, and EV charging station planning are critical to the security and resilience of the electric systems. This presentation describes several timely solutions to enable more secure and efficient grid operations by analyzing voluminous power system operation data. The aforementioned solutions include the multifunction intelligent relays, an environment-driven adaptive protection scheme, a transformer connectivity inferencing tool, and an EV charging station planning method. Several types of machine learning algorithms are developed in power systems to support renewable energy integration for sustainability. Date and Time: Thursday, November 21, 2019 - 1:30pm Venue: Y2E2 111 ## EE 292X (CEE 292X) Battery Systems for Transportation and Grid Services - Poster Session Topic: Student Poster Session, EE 292X (CEE 292X) Abstract / Description: ### Project poster session spanning a very broad range of topics from battery technology and modeling to applications to transportation and the grid. You are welcome to come and meet our students and learn about their amazing work. List of EE/CEE 292X projects: 1. Voltage sensing separator for battery fast charging 2. Equivalent circuit models for lithium ion batteries under EV drive cycles 3. Machine learning based models for lithium ion batteries 4. Characterizing error in linear battery dynamics model 5. Homogenized thermal runaway model in Li-ion cells 6. Battery pack design for thermal runaway prevention 7. Smart lithium ion battery pack for small-scale UAV applications 8. Battery-aware intelligence for autonomous robot navigation 9. Battery modeling to optimize range and cycle life for electric aircraft 10. Mileage prediction based on driving profiles 11. Data-driven system modeling of Stanford EV buses 12. Empirical trends in energy consumption of electric buses 13. Quantifying load impact from autonomous electric TNC fleets 14. Data-driven placement of charging station locations 15. Charging station locations via agent based simulation 16. Battery design for resilient decentralized wastewater treatment 17. Low cost, temperature robust batteries for farm applications 18. Battery charge controller for small scale off-grid wind 19. Techno-economic feasibility of a hybrid storage system for a university campus 20. Distributed vs grid scale storage systems for future EV charging stations 21. Ancillary services with vehicle to grid charging 22. Quantifying 2nd life EV battery value for grid applications Date and Time: Thursday, December 5, 2019 - 3:30pm Venue: Packard Atrium ## Pages ## 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 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: TBA Abstract / Description: TBA Date and Time: Thursday, December 3, 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 ## Pages ## Statistics and Probability Seminars ## Statistics Department Seminar presents "A Bayesian approach to contamination removal in molecular microbial studies" Topic: A Bayesian approach to contamination removal in molecular microbial studies Abstract / Description: High-throughput sequencing (HTS) allows the quantification of non-culturable microbial organisms in human health and disease states, including infectious diseases. However, contaminating nucleic acids (DNA) from external sources may lead to misidentification of a taxon's provenance. Sequencing controls can help to identify most of these contaminants through the use of statistical mixture models. We propose a Bayesian reference analysis based on a hierarchical model for the observed data, that infers the true intensities of a specimen's microbial DNA in the presence of microbial DNA contamination. By using the partial information about contamination intensities available in negative controls, we define a marginal likelihood and reference prior for the true intensities. Then, we obtain a marginal posterior distribution for the true intensities. In this talk, I will present the performance of the contamination removal method in the dilution series of the standard ZymoBIOMICS microbial community. I will also demonstrate our approach on two different low-biomass plasma specimens datasets. Our method is available as an open-source R package on Github. In addition, to identify contaminant sources, we provide a topic modeling approach to infer contaminant topics. Date and Time: Tuesday, June 2, 2020 - 4:30pm Venue: Zoom ID 935 0733 5349 (locks at 4:40pm PST) ## Probability Seminar welcomes Julia Palacios Topic: TBA Abstract / Description: Details TBA. Date and Time: Monday, June 15, 2020 - 4:00pm Venue: Zoom ## Probability Seminar welcomes Yuriy Nemish Topic: TBA Abstract / Description: details TBA Date and Time: Monday, June 8, 2020 - 4:00pm Venue: Zoom ## Probability Seminar presents "Optimal delocalization for generalized Wigner matrices" Topic: Optimal delocalization for generalized Wigner matrices Abstract / Description: We consider eigenvector statistics of large random matrices. When the matrix entries are sampled from independent Gaussian random variables, eigenvectors are uniformly distributed on the sphere and numerous properties can be computed exactly. In particular, it can be shown that extremal coordinates are no larger than$C\sqrt{\log N/N}$with high probability. There has been an extensive amount of work on generalizing such a result, known as delocalization, to a more general entry distribution. After giving a brief overview of the previous results going in this direction, we present an optimal delocalization result for matrices with sub-exponential entries for all eigenvectors. The proof is based on the dynamical method introduced by Erdös–Yau, the analysis of high moments as well as new level repulsion estimates which will be presented during the talk. This is based on a joint work with P. Lopatto. Date and Time: Monday, June 1, 2020 - 4:00pm Venue: Zoom ID 959 3090 9831 (locks at 4:10pm PST) ## Statistics Department Seminar presents "Data denoising and transfer learning in single cell transcriptomics" Topic: Data denoising and transfer learning in single cell transcriptomics Abstract / Description: Cells are the basic biological units of multicellular organisms. The development of single-cell RNA sequencing (scRNA-seq) technologies have enabled us to study the diversity of cell types in tissue and to elucidate the roles of individual cell types in disease. Yet, scRNA-seq data are noisy and sparse, with only a small proportion of the transcripts that are present in each cell represented in the final data matrix. We propose a transfer learning framework based on deep neural nets to borrow information across related single cell data sets for denoising and expression recovery. Our goal is to leverage the expanding resources of publicly available scRNA-seq data, for example, the Human Cell Atlas which aims to be a comprehensive map of cell types in the human body. Our method is based on a Bayesian hierarchical model coupled to a deep autoencoder, the latter trained to extract transferable gene expression features across studies coming from different labs, generated by different technologies, and/or obtained from different species. Through this framework, we explore the limits of data sharing: How much can be learned across cell types, tissues, and species? How useful are data from other technologies and labs in improving the estimates from your own study? If time allows, I will also discuss the implications of such data denoising to downstream statistical inference. Date and Time: Tuesday, May 26, 2020 - 4:30pm Venue: Zoom Meeting ID 910 4626 3951 ## Probability Seminar presents "Induced subgraphs with prescribed degrees mod q" Topic: Induced subgraphs with prescribed degrees mod q Abstract / Description: A classical result of Galai asserts that the vertex-set of every graph can be partitioned into two sets such that each induces a graph with all degrees even. Scott studied the (harder) problem of determining for which graphs can we find a partition into arbitrary many parts, each of which induces a graph with all odd degrees. In this talk we discuss various extensions of this problem to arbitrary residues mod$q\geq 3$. Among other results, we show that for every$q$, a typical graph$G(n,1/2)$can be equi-partitioned (up to divisibility conditions) into$q+1\$ sets, each of which spans a graph with a prescribed degree sequence.

A completely unrelated problem: Based on the same approach we obtained a non-trivial bound (but weaker than known results) on the singularity probability of a random symmetric Bernoulli matrix. The new argument avoids both decoupling and distance from random hyperplanes and it turns this problem into a simple and elegant exercise.

This is mostly based on a joint work with Liam Hardiman (UCI) and Michael Krivelevich (Tel Aviv University).

Date and Time:
Monday, May 18, 2020 - 4:00pm
Venue:
Zoom ID: 917 2019 2125 (meeting locked 10 min. after start)

## Statistics Department Seminar presents "Advancing medical research with 3D shape analysis of bioimaging data"

Topic:
Advancing medical research with 3D shape analysis of bioimaging data
Abstract / Description:

Advances in bioimaging techniques have enabled us to access the 3D shapes of a variety of structures: organs, cells, proteins. Since biological shapes are related to physiological functions, medical research is poised to incorporate more shape statistics. This leads to the question: how can we build quantified descriptions of shape variability from biomedical images

We first consider two biomedical analyses that require shape learning on small imaging datasets: (1) surgical planning for orthopedic surgery, and (2) research on pre-symptomatic biomarkers of Alzheimer's disease. We introduce elements of shape statistics to assess the accuracy of these studies. Then, we address a shape reconstruction challenge in pharmacological research: protein shape reconstruction using cryo-electron microscopy.

This talk shows how shape descriptors at different scales contribute to the development of precision medicine. The elements of geometric statistics required for this work are implemented in the open-source Python library Geomstats.

Date and Time:
Tuesday, May 19, 2020 - 4:30pm
Venue:
Zoom ID: 998 6129 8033 (meeting locked 10 min. after start)

## Statistics Department Seminar presents "Performative prediction"

Topic:
Performative prediction
Abstract / Description:

When predictions support decisions they may influence the outcome they aim to predict. We call such predictions performative the prediction influences the target. Performativity is a well-studied phenomenon in policy-making that has so far been neglected in supervised learning. When ignored, performativity surfaces as undesirable distribution shift, routinely addressed with retraining. We develop a risk minimization framework for performative prediction bringing together concepts from statistics, game theory, and causality. A conceptual novelty is an equilibrium notion we call performative stability. Performative stability implies that the predictions are calibrated not against past outcomes, but against the future outcomes that manifest from acting on the prediction. Our main results are necessary and sufficient conditions for the convergence of retraining to a performatively stable point of nearly minimal loss. In full generality, performative prediction strictly subsumes the setting known as strategic classification. We thus also give the first sufficient conditions for retraining to overcome strategic feedback effects.

This is joint work with Juan C. Perdomo, Tijana Zrnic, and Celestine Mendler-Dünner, and is available from Arxiv.

Date and Time:
Tuesday, May 12, 2020 - 4:30pm
Venue:
Zoom

## Statistics Department Seminar presents "Optimal procedures in private estimation"

Topic:
Optimal procedures in private estimation
Abstract / Description:

In this talk, I will review private procedures (typically called mechanisms) for releasing functions of a sample, focusing on differential privacy and related strong definitions of privacy. I will describe mechanisms that enjoy instance-optimal — meaning that in a strong sense, they achieve the best possible behavior for the given problem instance — guarantees. On the methodological side, I will highlight a few examples, including median estimation and statistical risk minimization. On the more theoretical side, I will describe techniques for giving such instance-optimal bounds, highlighting the desiderata I believe one must satisfy for an optimality result to truly mean optimal.

This is based on joint work with Hilal Asi and Feng Ruan.

Date and Time:
Tuesday, May 5, 2020 - 4:30pm
Venue:
Zoom

## Probability Seminar presents "Speeding up Markov chains with deterministic jumps"

Topic:
Speeding up Markov chains with deterministic jumps
Abstract / Description:

A striking example of the phenomenon: Consider simple random walk on the integers mod n [X(k+1)] = X(k) + epsilon(k+1)(mod n) where epsilon takes values {0,1,-1} with probability 1/3 each. This walk takes order n2 steps to get random. Now make a slight modification: X(k+1) = 2X(k) + epsilon(k+1) (mod n). This has the same amount of randomness BUT, for almost all n, the walk gets random in order log(n) steps.

In joint work with Sourav Chatterjee we show this as quite a general phenomenon. For any doubly stochastic Markov chain on n states and any permutation f(x) on the state space, the walk that goes from x to f(x) to y, where y is one step of the chain, mixes in order log (n) states for almost all permutations f. Since it happens for most f, this raises the problem of finding specific f for real problems. Some progress will be reported.

Date and Time:
Monday, April 27, 2020 - 4:00pm

## SystemX presents "Memory-Driven Computing - A perspective of this journey"

Topic:
Memory-Driven Computing - A perspective of this journey
Abstract / Description:

This talk will cover the use of memory technology within computing platforms, from building large memory systems, to use in neuromorphic computing. What use cases can benefit from novel use of Memory-Driven Computing techniques. How do the latest industry moves creating open memory fabrics (including Gen-Z and Compute Express Link) impact system design? The use of high bandwidth memories and non-volatile memories - where do these technologies play relative to each other? How can they impact the way we build systems to deal with the challenge of processing and gaining knowledge/insights from all the data we are collecting at exponentially growing rates.

Date and Time:
Thursday, May 28, 2020 - 4:30pm
Venue:
Zoom

## SystemX BONUS LECTURE: Edge TPU program and architecture overview

Topic:
Edge TPU program and architecture overview
Abstract / Description:

This talk will give an overview of how publicly announced products that have the Edge TPU make use of the product. The talk will then focus on what the Edge TPU architecture philosophy is the approach it takes to building custom silicon for ML workloads.

Join mailing list: Additional questions: Jon Candelaria, SystemX Seminar Instructor (jjcandel@stanford.edu)

Date and Time:
Tuesday, May 26, 2020 - 4:30pm
Venue:
Zoom

## SystemX presents "Simulating Realistic Human Motion for Robotics "

Topic:
Simulating Realistic Human Motion for Robotics
Abstract / Description:

Creating realistic virtual humans has traditionally been considered a research problem in Computer Animation primarily for entertainment applications. With the recent breakthrough in collaborative robots and deep reinforcement learning, accurately modeling human movements and behaviors has become a common challenge also faced by researchers in robotics and artificial intelligence. In this talk, I will first discuss our recent work on developing efficient computational tools for simulating and controlling human movements. By learning a differentiable kinematic constraints from the real world human motion data, we enable existing multi-body physics engines to simulate more humanlike motion. In a similar vein, we learn task-agnostic boundary conditions and energy functions from anatomically realistic neuromuscular models, effectively defining a new action space better reflecting the physiological constraints of the human body. The second part of the talk will focus on two different yet highly relevant problems: how to teach robots to move like humans and how to teach robots to interact with humans. While Computer Animation research has shown that it is possible to teach a virtual human to mimic real athletes' movements, the current techniques still struggle to reliably transfer a basic locomotion control policy to robot hardware in the real world. We developed a series of sim-to-real transfer methods to address the intertwined issue of system identification and policy learning for challenging locomotion tasks. Finally, I will showcase our effort on teaching robot to physically interact with humans in the scenarios of robot-assisted dressing and walking assistance.

Date and Time:
Thursday, May 21, 2020 - 4:30pm
Venue:
Zoom id: 865 305 030

## SystemX presents "Design and demonstration of on-chip integrated laser-driven particle accelerators"

Topic:
Design and demonstration of on-chip integrated laser-driven particle accelerators
Abstract / Description:

Particle accelerators represent an indispensable tool in science, healthcare, and industry. However, the size and cost of conventional radio-frequency accelerators limits the utility and reach of this technology. Dielectric laser accelerators (DLAs) provide a compact and cost-effective solution to this problem by driving accelerator nanostructures with visible or near-infrared (NIR) pulsed lasers, resulting in a factor of 10,000x reduction in scale. Current implementations of DLAs rely on free-space lasers directly incident on the accelerating structures, limiting the scalability of this technology due to the need of bulky optics and precise mechanical alignment. Therefore, integration with an inherently scalable architecture, such as photonic integrated circuits, is paramount to the development of an MeV-scale DLA for applications.

In this talk, I will present the demonstration of a waveguide-integrated DLA, designed using a photonic inverse design approach. I will first review the operation of DLAs and describe how one can formulate a figure-of-merit for the optimization of these structures. I will then briefly introduce the inverse design framework that allows for efficient free-form optimization of these structures, enabling search of a design-space that goes far beyond that of the tuning of a few geometric parameters. I will discuss the approaches we take to couple light to these devices before presenting the results of our single-stage on-chip integrated accelerator. I will conclude with the directions we are taking to reach higher on-chip acceleration gradients and energy-gain, including utilizing foundry fabrication for multi-stage accelerators.

Date and Time:
Thursday, May 14, 2020 - 4:30pm
Venue:
Zoom Meeting ID: 865 305 030

## SystemX BONUS LECTURE: Next Generation Neural Interfaces: From flexible neural probes to virtual optical waveguides

Topic:
Next Generation Neural Interfaces: From flexible neural probes to virtual optical waveguides
Abstract / Description:

Understanding the neural basis of brain function and dysfunction requires developing multimodal methods to record and stimulate neural activity in the brain with high spatiotemporal resolution. We have been designing high-density opto-electrical devices to enable bi-directional (read/write) interfacing with the brain for long-term chronic studies.

One of the challenges of optical techniques for structural and functional recording and imaging is the scattering and absorption of light, limiting light-based methods to superficial layers of tissue. To overcome this challenge, implantable photonic waveguides such as optical fibers or graded-index (GRIN) lenses have been used. The prohibitive size and rigidity of these optical implants cause damage to the brain tissue and vasculature. In this talk, I will discuss our research on developing next generation optical neural interfaces that are microfabricated on flexible materials to minimize damage to the tissue.

First, I will discuss a compact flexible photonic platform based on biocompatible polymers, Parylene C and PDMS, for high-resolution light delivery into the tissue in a minimally-invasive way. This photonic platform can be monolithically integrated with implantable electrical neural interfaces.

I will also discuss our recent work on developing a novel complementary method for confining and steering light in the tissue using ultrasound. I will show that ultrasound waves can sculpt virtual optical waveguides in the tissue to define and steer the trajectory of light, thus obviating the need for implanting invasive physical devices in the brain.

These novel neurophotonic techniques will enable a whole gamut of applications from fundamental science studies to designing next generation neural prostheses.

Date and Time:
Monday, May 11, 2020 - 4:30pm
Venue:
Zoom Meeting ID: 392 095 709

## SystemX presents "Consciousness"

Topic:
Consciousness
Abstract / Description:

No question in cognitive science is more challenging, or more fascinating, than the nature of consciousness. Until recently, the study of consciousness was usually considered a matter for philosophy rather than science, but there has been an explosion in the past decade of theories and experiments concerning how consciousness works. This talk will examine the nature of human consciousness from the interdisciplinary perspective of cognitive science. It will cover topics from the philosophy of mind, cognitive linguistics, neuroscience, psychology, and whether it may ever be possible for computers to be conscious, a topic studied in artificial intelligence.

Date and Time:
Thursday, May 7, 2020 - 4:30pm
Venue:
Zoom: stanford.zoom.us/j/865305030

## SystemX presents "Versal-ACAP Architecture, Programming, Machine Learning and 5G"

Topic:
Versal-ACAP Architecture, Programming, Machine Learning and 5G
Abstract / Description:

This presentation will provide an overview of one of the new generation of 7nm devices from Xilinx, the Versal ACAP multi-core vector processor. The overall device architecture together with a detailed description of the Vector processor datapath will be presented. The programming model for the device will be described along with some application use cases for machine learning inference and 4G/5G wireless radio will be covered.

Date and Time:
Thursday, April 30, 2020 - 4:30pm
Venue:
Zoom

## SystemX presents "Astrobee ISS Free Flyers: Overview and Enabling Technologies"

Topic:
Astrobee ISS Free Flyers: Overview and Enabling Technologies
Abstract / Description:

The Astrobee robots began operations on the International Space Station (ISS) in April of 2019. These 32-cm-wide, 9-kg, cube-shaped free flyers are capable of autonomously traversing the US Orbital Segment of ISS and performing tasks to assist astronauts in their day-to-day activities. The Astrobee Facility also provides an on-orbit testbed for guest scientists desiring to try new technologies in zero-g. This presentation will provide an overview of the Astrobee system and some of its key enabling technologies, including propulsion, navigation, and human interfaces. Additional information and publications can be found on the Astrobee website: nasa.gov/astrobee.

Date and Time:
Thursday, April 23, 2020 - 4:30pm
Venue:
Zoom

## SystemX presents "On-chip LIDAR with inverse design"

Topic:
On-chip LIDAR with inverse design
Abstract / Description:

LIDAR can provide detailed spatial maps of an environment, a capability that is essential for applica- tions such as autonomous driving, robotics, building modeling, or augmented reality. Bulky optical elements and moving parts in current LIDAR systems have unfortunately made these systems heavy, expensive, and vibration-sensitive. Solid-state optical devices for the functionalities required for a LIDAR system have therefore driven much integrated photonics research in recent years. For on-chip beam-steering, optical phased arrays (OPAs) have emerged as a promising solution; however, the size and efficiency specifications for an effective LIDAR-OPA design have remained challenging for classical photonics design methods. In this talk, I will present how photonic inverse design methods can improve OPA design. Unlike classical photonic design, inverse design allows for arbitrary device geometries through the use of advanced elec- tromagnetic optimization methods. The extra degrees of freedom these methods provide has resulted in numerous new photonic devices with improved efficiency, reduced on-chip footprint or novel functionali- ties. Leveraging these new capabilities, we demonstrate an OPA design with a larger scanning cone and a smaller operating bandwidth as compared to the classical photonic design solutions.

Date and Time:
Thursday, April 16, 2020 - 4:30pm
Venue:
Zoom

## SystemX presents "Quantum computers from Superconducting qubits"

Topic:
Quantum computers from superconducting qubits
Abstract / Description:

Quantum computers powered by hundreds of gate based, superconducting qubits are just over the horizon. Several groups have already announced activities on quantum processors (QP) of 50 qubits or more. The systems containing these processors will be of fundamental importance in quantum algorithm development, on our path toward quantum advantage in the noisy intermediate scale quantum (NISQ) era. Quantum advantage is the point at which quantum computers can solve a problem faster, cheaper, or more accurately than their classical counterparts, which is likely to be accomplished before fully fault tolerant machines are available. This talk will address the trade-offs in the design of hybrid quantum-classical computing systems based on gate based superconducting processors approaching 100 qubits.

Date and Time:
Thursday, April 9, 2020 - 4:30pm
Venue:
Zoom