Graduate

IT-Forum

Topic: 
A Stronger Soft-Covering Lemma that assures Semantic Security in Wiretap Channels
Abstract / Description: 

In 1975, Wyner published two very different papers that are unexpectedly connected. One introduced the wiretap channel, showing that information-theoretic secrecy is possible without a secret key by taking advantage of channel noise. This is the foundation for much of physical-layer security. The other paper introduced a notion of common information relevant to generating random variables at different terminals. In that work he introduced a soft-covering tool for proving achievability. Coincidently, soft covering has now become the tool of choice for proving strong secrecy in wiretap channels, although Wyner didn't appear to make any connection between the two results.

We present a sharpening of the soft-covering tool by showing that the soft-covering phenomenon happens with doubly-exponential certainty with respect to a randomly generated codebook. Through the union bound, this enables security proofs in settings where many security constraints must be satisfied simultaneously. The "type II" wiretap channel is a great example of this, where the eavesdropper can actively influence his observations but security must hold in all cases. We demonstrate the effectiveness of this tool by deriving the secrecy capacity of wiretap channels of type II with a noisy main channel---previously an open problem. Additionally, this stronger soft covering allows information-theoretic security proofs to be easily upgraded to semantic security, which is the gold standard in cryptography.

Date and Time: 
Friday, November 6, 2015 - 1:00pm to 2:00pm
Venue: 
Packard 202

SystemX Seminar

Topic: 
Smart Low-Power MEMS Help Usher in the Wearable Era
Abstract / Description: 

Wearable devices are finally transitioning from hype to mainstream, aided by integration of valuable transducers, identification of application and use cases, ramp up of cloud services, and increased public awareness and interest due to Apple's watch introduction. Although still a nascent field, several themes are emerging that this talk will explore. The first is the evolution of capability from performing simple functions such as step count, to becoming contextually aware products. The second theme is the implications of targeting far more than just the wrist for the wearable device's residence. The third arises from the desire for "always on" capability, small size limit, and appeal of charging only every few days. In consequence, power is one of the most important parameters impacting the entire system design.

Date and Time: 
Thursday, November 5, 2015 - 4:30pm to 5:30pm
Venue: 
Y2E2 - 111

EE380 Computer Systems Colloquium

Topic: 
$9 Computer Architecture: The Chips That Make C.H.I.P., C.H.I.P.
Abstract / Description: 

Features: 1GHz ARM Cortex A8, 512MB RAM, 4GB NAND Flash, WiFi, Bluetooth.

Completely open source.

This talk will provide a technical overview of the hardware and software system architecture of the world's first $9 computer.

Date and Time: 
Wednesday, November 4, 2015 - 4:30pm to 5:30pm
Venue: 
Gates B03

SmartGrid Seminar

Topic: 
Modeling, Visualizing and Mitigating the Impacts of Geomagnetic Disturbances on the Electric Power Grid
Abstract / Description: 

As never before our modern society depends on a reliable supply of electricity, and for the vast majority of people that electricity comes from the large, interconnected grids that crisscross the world. The smart grid vision is to utilize modern technology to transform the grid, to provide the sustainable electric infrastructure needed to provide us with a bright future. However, there is the potential for what the North America Electric Reliability Corporation (NERC) calls High-Impact, Low-Frequency (HILF) events to plunge us into darkness. This presentation covers one such HILF risk, geomagnetic disturbances (GMDs). GMDs, which are caused by corona mass ejections (CMEs) from the sun, have the potential to affect the power grid. This is due to the CMEs impacting the earth's magnetic field, which in turn can induce quasi-dc electric fields in the earth (with frequencies usually much below 1 Hz). These electric fields then cause geomagnetically induced currents to flow in the high voltage grid that can cause half-cycle saturation in the power transformers, resulting in increased transformer reactive power losses resulting in widespread blackouts and, perhaps, transformer damage. This presentation provides an overview of the impact of GMDs on the grid, shows how this impact can be modeled and visualized, and discusses mitigation strategies.

Date and Time: 
Thursday, November 5, 2015 - 1:30pm to 2:30pm
Venue: 
Y2E2 300

Electrical Engineering Talk

Topic: 
Things I Wish I Knew as a Grad/Post-Doc/First Year Assistant Professor (about academic jobs)
Abstract / Description: 

Prof. Eric Pop of Electrical engineering will share about his journey through the late years of grad school, postdoc, and early academia, including an honest discussion of mistakes, missteps and misconceptions (many that he has personally had to overcome). Prof. Pop received his PhD in EE from Stanford (2005), BS/M.Eng in EE and BS in Physics from MIT (1999). He did a postdoc at Stanford, worked at Intel, was Assistant then Associate Professor at University of Illinois Urbana-Champaign, and joined the EE faculty at Stanford in 2013.

PLEASE RSVP

Date and Time: 
Tuesday, November 3, 2015 - 12:00pm to 1:30pm
Venue: 
Packard 202

Stanford Computer Forum and SystemX Seminar

Topic: 
Silicon Engineering at Apple
Abstract / Description: 

The last decade has seen massive improvements in mobile compute performance, along with dramatic improvements in power efficiency. At Apple, custom SoC designs drive multiple product breakthroughs. The CPU inside the Apple A9 chip in iPhone 6s runs up to 70% faster and the GPU up to 90% faster than they did in the A8, delivering both desktop-class and console-class performance that you can hold in your hand. This has all been done without decreasing battery life. In this talk some of the unique technical challenges faced by mobile SoC designers will be discussed, along with some of the complex decisions that are considered when engineering silicon at Apple.

Light refreshments will be provided following the talk. Students seeking permanent or intern positions at Apple are encouraged to bring a resume.

Date and Time: 
Tuesday, November 3, 2015 - 4:30pm to 5:30pm
Venue: 
Hewlett 200

Special Seminar

Topic: 
Conquering MPSoC Complexity with Bio-Inspired Self-Organization
Abstract / Description: 

The complexity of hardware/software systems evolved as THE grand challenge for the effective deployment of multi-/many-core processor platforms in embedded and high performance computing systems. Whether we struggle with MPSoC power, resilience, mixed-criticality guarantees, software debugging or security shortcomings, all these are consequences of the economically driven increase in function integration and growing system complexity. Nature has intriguingly powerful mechanisms to cope with the inherent complexity of living organisms. For example, the visceral nervous and immune systems control vital body functions without conscious involvement. On a higher layer, the somatic nervous system or brain allows cognition, reasoning and learning. Both layers are dominantly founded on the principle of emergent self-organization: system constituents follow few, individual and simple rules which manifest in a desirable overall system behavior (or the opposite, chaotic behavior, which usually is being eliminated in nature through evolution). These principles inspired initiatives like autonomic and organic computing, cognitive sciences and humanoid robotics.

My talk will first provide an overview on the research activities at our institute, which are focused on architectures, accelerators and design methods for application specific MPSoC. I will then show examples for the successful application of self-organization principles on homogeneous MPSoC. Thereby, workload balancing and optimization of power consumption and system resilience were the target objective functions. Evolution, i.e. the identification of efficient local rules and behaviors, is being emulated by means of generic online and hardware-based reinforcement machine learning techniques. I will close with an outlook towards applying these concepts in the contexts of MPSoC diagnosis / software debugging and SDN/NFV (software defined networking/network function virtualization) scaling.

Date and Time: 
Monday, November 2, 2015 - 4:30pm to 5:30pm
Venue: 
Gates 415

Invited Talk: GaN Electronics

Topic: 
GaN Electronics– the Challenges of Phonons, Electrons and the Sparkling Diamond
Abstract / Description: 

GaN electronic devices are presently being developed for microwave and power applications. Many challenges remain in particular how to manage heat and charge carrier trapping. Prof. Kuball will review his latest work in this field, including the benefit of using diamond for thermal heat sinking as well of carbon doping of the GaN and its implication on charge carrier trapping and electrical conduction.

Date and Time: 
Monday, October 26, 2015 - 4:00pm to 5:00pm
Venue: 
Allen 101X

SystemX Seminar

Topic: 
Cognitive Layering in Embedded Computing
Abstract / Description: 

Embedded computing is often computing with extremes – extreme low cost, extreme low energy, extreme low latency, extreme high computation rates. Increasingly, it is about extreme responsiveness, connectedness and intelligence. Systems often need to maintain the energy illusion of "always off" and the computational illusion of "always on". This talk addresses this seeming paradox with the notion of 'cognitive layering', a hierarchy of processing subsystems making widely shifting trade-offs between generality and efficiency. Along the way we touch on key emerging embedded computing functions in vision, convolutional neural networks, ultra-low-power processing and distributed software environments.

Date and Time: 
Thursday, October 29, 2015 - 4:30pm to 5:30pm
Venue: 
Y2E2 - 111

Statistics Seminar

Topic: 
Sparse Inverse Problems
Abstract / Description: 

We present an efficient algorithm and theoretical analysis for an infinite-dimensional analogue of the Lasso. 

Compressed sensing seeks to explain an observed signal as the noisy measurement of a few weighted sources. Identifying a weighted collection of parametric sources with a measure on the parameter space allows one to estimate the underlying sources using an infinitedimensional analogue of the Lasso. In many applications the mapping from parameters to observations is differentiable; we propose an algorithm and theoretical analysis that leverages structure in the measurement mapping. 

We propose an algorithm that interleaves conditional gradient steps on the infinite-dimensional Lasso with nonconvex local search over the parameter space. We outline applications of our algorithm to super-resolution imaging, low-rank matrix completion, linear system identification, and radiation treatment planning. 

We prove that in ideal settings the optimization problem recovers the true parameters. Precisely, we restrict our theoretical analysis to the setting with a one-dimensional parameter space, positive weights, and noiseless observations. We establish conditions on the measurement function such that minimizing the weighted total variation recovers the true parameters and weights, with no minimum separation condition on the source locations

Date and Time: 
Tuesday, October 27, 2015 - 4:30pm to 5:30pm
Venue: 
Sequoia Hall, Room 200

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