Seminar

NPI Zoom Seminar-Xiaoqi (Danny) Chen

Network measurement is a vital tool for network operators to diagnose outages, optimize performance, and detect attacks. Recently, the development of programmable switches has enabled us to run measurement algorithms in the network switch directly, and analyze packets up to Tbps in throughput. However, the programming model of programmable switches is extremely constrained, which restricts the types of algorithms we can run in them.
 
To achieve much-needed measurement goals of network operators, we design tailored algorithms to adapt to the programming constraints imposed by practical programmable switches. We first present PRECISON, which attempts to answer the Heavy-Hitter Flow Detection problem (find out  which flows sent the largest number of packets). PRECISION can accurately identify the heavy-hitter
flows using a small amount of memory, by recirculating a small number of packets probabilistically. Then, we present Snappy, which tries to solve the Heavy Flow in the Queue problem (which flows occupied a large fraction of queuing buffer). Snappy can pinpoint the bursty flows causing ephemeral long queues and potential packet loss, by maintaining multiple traffic snapshots of short time intervals. Our measurement algorithms enable network operators to perform immediate actions against these specific network flows, inhibiting congestion in real-time, while potentially improving service quality for other network flows.
 
Bio:
Xiaoqi is a second year PhD student at Department of Computer Science, Princeton University,  advised by Prof. Jennifer Rexford. Before joining Princeton, he received his Bachelor's degree from  Institute for Interdisciplinary Information Sciences (Yao class), Tsinghua University. His research is  running network measurements in programmable switches. Interests also include data center  networking, sketches, and network science. 
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Abstract:
We illustrate through two examples some new challenges that network, information, and control theories are facing in a world of widespread sensing, ubiquitous connectivity, and availability of massive data. In the first part of the talk, we argue that in this new context the focus of network science should shift from studying the structural properties of the network to modeling the process dynamics occurring over the network, including the human dynamics. To elaborate on this point of view, we consider a Shelling-type model of agent dynamics leading to community formation in large networks that is related to the Ising model of statistical physics. We show how the model can be solved rigorously, after 50 years from its introduction, and what lessons can be learned from this new analysis. In the second part of the talk, we shift the focus from the analysis of dynamical systems to their control. We argue that in cyber-physical systems control must be performed over communication channels, and observations corrupted by noise are subject to delay and erasures. In this new framework, one of the central results is the data-rate theorem, describing the trade-off between the system dynamics and the data-rate available over the feedback loop. After reviewing this classic result, we show that the new paradigm of event-triggering control provides a completely new perspective, leading to new insights on the information-theoretic value of timing in communication.
 
Bio:
Massimo Franceschetti received the Laurea degree (with  honors) in computer engineering from the University of Naples, Naples, Italy, in 1997, the M.S. and Ph.D. degrees in ele trical engineering from the California Institute of Technology, Pasadena, CA, in 1999, and 2003, respectively. He is Professor of Electrical and Computer Engineering at the University of California at San Diego (UCSD). Before joining UCSD, he was a postdoctoral scholar at the University of California at Berkeley for two years.  He is co-author of the book “Random Networks for Communication” and author of the book “Wave theory of information,” both published by Cambridge University Press. Dr. Franceschetti served as Associate Editor for Communication Networks of the IEEE Transactions on Information Theory (2009 – 2012), as associate editor of the IEEE Transactions on Control of Network Systems (2013- 2016), as Associate Editor of the IEEE Transactions on Network Science and Engineering (2014-2017) and as Guest Associate Editor of the IEEE Journal on Selected Areas in Communications (2008, 2009).  He is an IEEE Fellow and was awarded the C. H. Wilts Prize in 2003 for best doctoral thesis in electrical engineering at Caltech; the S.A. Schelkunoff Award in 2005 for best paper in the IEEE Transactions on Antennas and Propagation, a National Science Foundation (NSF) CAREER award in 2006, an Office of Naval Research (ONR) Young Investigator Award in 2007, the IEEE Communications Society Best Tutorial Paper Award in 2010, and the IEEE Control theory society Ruberti young researcher award in 2012.

EE Departmental Seminars

Abstract:
Structural proteins are Nature’s building blocks, conferring stiffness, structure, and function to ordinarily soft biological materials. Such proteins are polymorphic which allows controlling the end material format through their self-assembly. These biomaterials provide a unique opportunity by being simultaneously “technological” (e.g. mechanically robust, micro- and nanostructured, high-performing) and “biological” (e.g. living, adaptable, bio-functional) making them ideally suited for applications at the interface between these two domains. 
 
Bio:
Fiorenzo G. Omenetto is the Frank C. Doble Professor of Engineering, and a Professor of Biomedical Engineering at Tufts University.  He also holds appointments in the Department of Physics and the Department of Electrical Engineering. His research interests are at the interface of technology, biologically inspired materials and the natural sciences with an emphasis on new transformative approaches for sustainable materials for high-technology applications.  He also serves as Dean for Research for the School of Engineering. He has proposed and pioneered the use of silk as a material platform for advanced technology with uses in photonics, optoelectronics and nanotechnology applications, is co-inventor on several disclosures (~100) on the subject, and is actively investigating applications of this technology base both for technical and design applications.  He is a co-founder of three startups and has active roles in their governance.
Prof. Omenetto was formerly a J. Robert Oppenheimer Fellow at Los Alamos National Laboratories, a Guggenheim Fellow, and is a Fellow of the Optical Society of America and of the American Physical Society and a Senior Member of SPIE and is a Tallberg Foundation Global Leadership Fellow.  He was named one of the 50 top people in tech by Fortune magazine in a class including (among others) Steve Jobs, Jeff Bezos, Larry Page, Shigeru Miyamoto.  His research has been featured extensively in the press with coverage in the most important media outlets worldwide.

EE Departmental Seminars

Abstract:
Recent advances in condensed matter, optical, and atomic physics led to the emergence of highly controllable synthetic quantum matter, such as superconducting circuits, implanted solid-state defects, trapped atoms or ions, and strongly interacting photons. In addition to allowing us to gain fundamental insights into peculiar and diverse behavior of many-body -- that is, large and interacting -- quantum systems, synthetic quantum matter paves the way for building revolutionary quantum technologies such as extraordinarily powerful computers, unbreakably secure communication devices, and exceptionally accurate sensors. In this talk, we will explore two facets of synthetic quantum matter. First, we will argue that sampling complexity, that is the question of how hard it is to produce a sample from a given probability distribution, lies at the heart of understanding and harnessing synthetic quantum matter. Second, we will show how to engineer interactions between individual photons and use these interactions for building quantum technologies and accessing exotic few-body and many-body physics. Finally, we will put this work in the context of a broader quest to design, understand, control, and harness synthetic quantum matter. 

Bio:
Alexey Gorshkov received his A.B. and Ph.D. degrees from Harvard in 2004 and 2010, respectively. In 2013, after three years as a Lee A. DuBridge Postdoctoral Scholar at Caltech, he became a staff physicist at NIST. At the same time, he started his own research group at the University of Maryland, where he is a fellow of the Joint Quantum Institute and of the Joint Center for Quantum Information and Computer Science. His theoretical research is at the interface of quantum optics, atomic physics, condensed matter physics, and quantum information science. Applications of his research include quantum computing, quantum communication, and quantum sensing.

Many academic fields, including engineering and computer science, have persistent gender gaps despite attempts to encourage women’s participation. While this is often characterized as a problem faced by STEM fields, some humanities disciplines such as philosophy face precisely the same challenges, while some STEM disciplines such as molecular biology are far more gender-balanced. Are there any isolable factors that predict the occurrence of gender gaps across the entire academic spectrum? This talk presents data suggesting that one such factor may be academics' beliefs about what is required for success in their discipline. In some fields, success is viewed primarily as a matter of hard work and dedication -- but in others, success is seen as requiring a special, unteachable spark of brilliance. Cultural stereotypes strongly associate this sort of raw genius with men rather than women -- where are the female Sherlock Holmes, Dr. Houses, or Will Huntings? -- meaning that women may be discouraged from pursuing careers in such fields. These findings point to new strategies for increasing women’s participation in STEM, and indicate concrete measures that might be implemented in SEAS classrooms to better include and encourage women students.

Abstract: The throughput of existing wireless networks is often limited by interference. One fundamental reason is that the current designs are constrained by a "one-transmission-at-a-time" model at the link layer and a fixed-width spectrum allocation at the physical layer. We present a new wireless design that exploits traffic burstiness and node heterogeneity, thereby improving concurrency and spectrum usage. The main challenge is the unmanaged nature of many wireless networks such as 802.11 and mesh, which makes centralized resource allocation impractical. We show through analysis and implementation that simple randomized allocation policies can overcome this challenge, and improve throughput by 2x or more.

This work is joint with Rabin Patra, Hari Balakrishnan and Eric Brewer.

Bio: Ramakrishna Gummadi is a post-doc at the MIT Computer Science and Artificial Intelligence Laboratoray (CSAIL). He obtained his B.Tech. from IIT-Madras, M.S. from UC Berkeley and Ph.D. from USC, all in Computer Science. His dissertation was about reliable and efficient programming languages for sensor networks. He is interested in building scalable and reliable systems and networks based on sound principles. His awards include a UC Regents Graduate Fellowship, a best paper awarded out of all 2001 Journal of Computer Networks papers, a best poster/demo award at SenSys 2004, and an award at the ACM Student Research Competition (SRC) held at PLDI 2007.

The Barrelfish OS is a new open-source operating system for heterogeneous multicore systems being developed at ETH Zurich, in conjunction with Microsoft Research in Cambridge.

This talk will say why we think we can write a new OS, and why we think we should. Hand-in-hand with increasing hardware parallelism is increasing hardware diversity, even within a single machine. Furthermore, the drive towards multicore programmability is beginning to result in interesting language and runtime features whose I/O and scheduling requirements may not be well served by existing OS structure.

Barrelfish seeks to meet these challenges by viewing a multicore machine more as a networked system than as a single, monolithic computer, and applying results from distributed computing to scaling a single OS instance across many heterogeneous cores. We also apply knowledge representation techniques to allow the OS and applications to reason about the richness of the hardware at runtime, in the interests of continuous performance optimization. I'll talk about how these approaches lead to a novel way of structuring an OS, and the current status and future directions of the system. ork).ABSTRACT: The Barrelfish OS is a new open-source operating system for heterogeneous multicore systems being developed at ETH Zurich, in conjunction with Microsoft Research in Cambridge. This talk will say why we think we can write a new OS, and why we think we should. Hand-in-hand with increasing hardware parallelism is increasing hardware diversity, even within a single machine. Furthermore, the drive towards multicore programmability is beginning to result in interesting language and runtime features whose I/O and scheduling requirements may not be well served by existing OS structure. Barrelfish seeks to meet these challenges by viewing a multicore machine more as a networked system than as a single, monolithic computer, and applying results from distributed computing to scaling a single OS instance across many heterogeneous cores. We also apply knowledge representation techniques to allow the OS and applications to reason about the richness of the hardware at runtime, in the interests of continuous performance optimization. I'll talk about how these approaches lead to a novel way of structuring an OS, and the current status and future directions of the system.

Computing the Future of Biomedicine

Computers have changed the way we live, work, and even recreate.

Now, they are transforming how we think about and treat human disease.

Advanced techniques in biomedical computing, imaging, and visualization are already changing the face of biology and medicine in both research and clinical practice. These techniques have the potential to provide comprehensive models and views of the human body in unprecedented depth and detail. As a result, biomedical computing and visualization will help produce exciting new biomedical scientific discoveries and clinical treatments. In this talk, I will discuss the state of the art in biomedical computing, medical imaging, and visualization research and present examples of their vital roles in cardiology, neuroscience, neurosurgery, and radiology.

Grid computing seeks to harness idle computing power on the Internet to create a huge supercomputer available to the public. Many obstacles exist to making this vision a reality; a primary obstacle is the understandable reluctance of computer owners to execute code from sources they do not trust. This obstacle limits participation in the grid to the small number who can afford to cultivate pre-arranged trust relationships for their applications.

The ConCert project seeks to make the grid universally usable by eliminating the need for trust when disseminating applications. This is achieved using certified code to ensure that grid applications comply with a safety policy. However, certified code can raise other obstacles to universal usability. In particular, if a safety policy is overly specific, it may unnecessarily limit the number of applications that can comply, and therefore limit the number that can use the grid.

This talk discusses our work to resolve this issue through foundational certified code, wherein the safety policy is as general as possible. Foundational certified code has been infamously difficult to work with, as its certificates must include complete (and typically complicated) safety arguments to the level of the concrete architecture that tend. We discuss our system, called TALT, which employs a unique methodology based in metalogic and operational semantics that ameliorates these difficulties.

(This is joint work with Susmit Sarkar.)