- talks - lists.cs.princeton.edu

Talk: Renata Teixeira, Broadband Internet Performance: A View From the Gateway, Mon Nov 12, 10am
by Nicole E. Wagenblast 12 Nov '12

12 Nov '12

Broadband Internet Performance: A View From the Gateway Renata Teixeira , University of Paris (LIP6) Monday, November 12, 2012, 10am Computer Science Room 402 Policymakers, ISPs, and users are increasingly interested in studying the performance of Internet access links. This talk will first present our findings on the the accuracy and overhead of state-of-the-art available bandwidth estimation tools to measure residential broadband throughput. Because of many confounding factors in a home network or on end hosts, however, thoroughly understanding access network performance requires deploying measurement infrastructure in users’ homes as gateway devices. This talk will then present the first study of network access link performance measured directly from home gateway devices. In conjunction with the Federal Communication Commission’s study of broadband Internet access in the United States, we study the throughput and latency of network access links using longitudinal measurements from nearly 4,000 gateway devices across 8 ISPs from a deployment of over 4,200 devices. We study the performance users achieve and how various factors ranging from the user’s choice of modem to the ISP’s traffic shaping policies can affect performance. Our study yields many important findings about the characteristics of existing access networks. Our findings also provide insights into the ways that access network performance should be measured and presented to users, which can help inform ongoing broader efforts to benchmark the performance of access networks. The work presented in this talk appeared at: -O. Goga, R. Teixeira, "Speed Measurements of Residential Internet Access", in Proc. of Passive and Active Measurement Conference, March 2012. -S. Sundaresan, W. de Donato, N. Feamster, R. Teixeira, S. Crawford, and A. Pescape, "Broadband Internet Performance: A View From the Gateway", in Proc. of ACM SIGCOMM, August 2011. Renata Teixeira received the B.Sc. degree in computer science and the M.Sc. degree in electrical engineering from Universidade Federal do Rio de Janeiro, Brazil, in 1997 and 1999, respectively, and the Ph.D. degree in computer science from the University of California, San Diego, in 2005. During her Ph.D. studies, she worked on Internet routing at the AT&T Research. She is currently a researcher with the Centre National de la Recherche Scientifique (CNRS) at LIP6, UPMC Sorbonne Universites, Paris, France. She was a visiting scholar at UC Berkeyley/ICSI. Her research interests are in measurement, analysis, and management of data networks. She has authored more than 40 papers in this area. Renata serves in the editorial board of the IEEE/ACM Transactions on Networking and of the ACM SIGCOMM Computer Communication Review. She is also a member of the steering committee of the ACM Internet Measurement Conference and has been active in the program committees of ACM SIGCOMM, ACM IMC, PAM, IEEE INFOCOM, among others.

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Colloquium speaker Molly Steenson, Wednesday Nov, 7 at 4:30pm
by Nicole E. Wagenblast 07 Nov '12

07 Nov '12

"To the first machine that can appreciate the gesture:" Nicholas Negroponte and the MIT Architecture Machine Group Molly Steenson , Assistant Professor, School of Journalism & Mass Communication, University of Wisconsin-Madison PhD Wednesday, November 7, 2012 , 4:30pm Computer Science Small Auditorium (Room 105) Nicholas Negroponte today is best known for founding the MIT Media Lab in 1985. But before the Media Lab, he founded the Architecture Machine Group at MIT in 1968 (Arch Mach for short). As an architect captivated by computers, Negroponte created the lab as a test bed for interactive computers, sensors and programs that sought to change the manner in which computers and humans interacted with each other. He envisioned a world in which everybody would live in immersive, intelligent environments, even dedicating his first book The Architecture Machine “To the first machine that can appreciate the gesture." But what is the nature of that gesture? Arch Mach's structure and funding benefited from the same relationships as MIT’s major engineering and computing labs, collaborating especially closely with the Artificial Intelligence Lab, and its projects echoed the dynamics of Department of Defense funding that occurred in AI. In this talk, I will introduce Arch Mach's projects, projections—and gestures. Molly Wright Steenson is a Ph.D. candidate in Princeton University’s School of Architecture where she researches the history of architecture and information. In January 2013, she will join the faculty of the University of Wisconsin-Madison in the School of Journalism & Mass Communication, where she will focus on digital media studies. Steenson was also a professor at the Interaction Design Institute Ivrea in Italy. As a design researcher, she examines the effect of personal technology on its users, with recent projects in India and China for Microsoft Research and Intel Research and ReD Asscoiates. Prior to her scholarly career, Molly started working with the Web in 1994, producing sites and leading design strategy for Reuters, Netscape, and Razorfish. She holds a Master’s in Environmental Design from the Yale School of Architecture and a B.A. in German from the University of Wisconsin-Madison.

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H Kim preFPO
by Melissa M. Lawson 06 Nov '12

06 Nov '12

Hanjun Kim will present his preFPO on Tuesday November 13 at 8:30 AM in Room 402. The members of his committee are: David August, advisor; David Wentzlaff and Kai Li, readers; JP Singh and Sharad Malik, nonreaders. Everyone is invited to attend his talk. His abstract follows below. ---------------------- ASAP: Automatic Speculative Acyclic Parallelization Speculative Decoupled Software Pipelining (Spec-DSWP) is a promising automatic parallelization technique that speculatively partitions a loop into multiple threads that communicate in a pipelined manner. Speculation can complement conservative static analysis, making automatic parallelization more robust and applicable. Pipelining allows Spec-DSWP to speculate only rarely occurring dependences while respecting the other dependences through communication among threads. Acyclic communication patterns in pipelining make the parallelized programs tolerant of communication latency. However, since Spec-DSWP partitions a loop iteration (a transaction) into multiple sub-transactions across multiple threads according to the pipeline stages, a special runtime system is required that supports multi-threaded transactions (MTX). This dissertation proposes Automatic Speculative Acyclic Parallelization (ASAP) that supports Spec-DSWP on real hardware without any hardware modiﬁcation. ASAP consists of a speculative acyclic parallelizing compiler and an MTX runtime system. The ASAP compiler automatically parallelizes loops using the Spec-DSWP transformation, and the ASAP runtime system correctly executes the speculatively transformed programs. With synergistic combination of speculation, acyclic communication, and runtime system support, ASAP achieves scalable performance for a wide range of applications on various parallel platforms such as multicore machines and clusters without any hardware modiﬁcation.

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Colloquium speaker Michael Walfish Friday, Oct 26
by Nicole E. Wagenblast 26 Oct '12

26 Oct '12

Making proof-based verified computation almost practical Michael Walfish , The University of Texas at Austin Computer Science Small Auditorium, Room 105 Friday, October 26, 2012, 3:30pm How can a machine specify a computation to another one and then, without executing the computation, check that the other machine carried it out correctly? And how can this be done without assumptions about the performer (replication, trusted hardware, etc.) or restrictions on the computation? This is the problem of _verified computation_, and it is motivated by the cloud and other third-party computing models. It has long been known that (1) this problem can be solved in theory using probabilistically checkable proofs (PCPs) coupled with cryptographic tools, and (2) the performance of these solutions is wildly impractical (trillions of CPU-years or more to verify simple computations). I will describe a project at UT Austin that challenges the second piece of this folklore. We have developed an interactive protocol that begins with an efficient argument [IKO CCC '07] and incorporates new theoretical work to improve performance by 20+ orders of magnitude. In addition, we have broadened the computational model from Boolean circuits to a general-purpose model. We have fully implemented the system, accelerated it with GPUs, and developed a compiler that transforms computations expressed in a high-level language to executables that implement the protocol entities. The resulting system, while not quite ready for the big leagues, is close enough to practicality to suggest that in the near future, PCPs could be a real tool for building actual systems. Talk will be based on these papers and ongoing work: * http://www.cs.utexas.edu/~mwalfish/papers/ginger-usec12.pdf * http://www.cs.utexas.edu/~mwalfish/papers/pepper-ndss12.pd Michael Walfish is an assistant professor in the Computer Science Department at The University of Texas at Austin. His research interests are in systems, security, and networking. His honors include an Air Force Young Investigator Award, an NSF CAREER Award, a Sloan Research Fellowship, a Teaching Excellence Award from the UT College of Natural Sciences, the Intel Early Career Faculty Honor Program, and the UT Society for Teaching Excellence. He received his B.A. from Harvard and his Ph.D. from MIT, both in Computer Science.

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Talk- Theodore Johnson of ATT Labs Wed. Oct 24
by Nicole E. Wagenblast 19 Oct '12

19 Oct '12

Hi all, Theodore Johnson will be visiting the department from ATT Labs on Wednesday, October 24. He'll be giving a talk about Data Stream Warehousing. The talk will be 12 noon to 1:30 pm, in Room 302. Abstract: Data stream processing is a well-studied area that has led to many commercial offerings. Stream processing systems typically store only a small history of a stream, and provide services such as real-time alerting and visualization, and data reduction for downstream processing. However many applications also require that long term (e.g. 2 year) histories as well as real-time data be provided to analysts. A stream warehouse combines aspects of data stream processing (continual data ingest) with data warehousing (long-term storage and materialized views). I will discuss special issues and opportunities that arise in stream warehousing, and stream warehouse applications within AT&T Labs - Research. Bio: Theodore Johnson received a PhD in Computer Science from New York University in 1990. From 1990 through 1996, he was an Associate Professor at the CISE department of the University of Florida. In 1996, Ted moved to the Database Research group of AT&T Labs - Research and has been there since. Ted has specialized in data steam management systems, being one of the principal authors of the GS Tool (previously, Gigascope) and of the DataDepot stream warehouse. Ted has written two books, Distributed Operating Systems and Algorithms (with Randy Chow) and Exploratory Data Mining and Data Cleaning (with Tamraparni Dasu). -- Ari Rabkin asrabkin(a)gmail.com Princeton Computer Science Department

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CS Colloquia on making PCP practical: Friday 10/26 @ 3:30pm
by Mike Freedman 19 Oct '12

19 Oct '12

[Mike is a systems researcher who, along with students, has been working on this problem with Andrew Blumberg. Andrew is a mathematician who spent 2007-2008 at IAS. So, this talk might be interesting to some folks on varying backgrounds.] --- Making proof-based verified computation almost practical Michael Walfish, The University of Texas at Austin Friday, October 26, 2012, 3:30 PM - 4:30 PM CS Small Auditorium (Room 105) --- How can a machine specify a computation to another one and then, without executing the computation, check that the other machine carried it out correctly? And how can this be done without assumptions about the performer (replication, trusted hardware, etc.) or restrictions on the computation? This is the problem of _verified computation_, and it is motivated by the cloud and other third-party computing models. It has long been known that (1) this problem can be solved in theory using probabilistically checkable proofs (PCPs) coupled with cryptographic tools, and (2) the performance of these solutions is wildly impractical (trillions of CPU-years or more to verify simple computations). I will describe a project at UT Austin that challenges the second piece of this folklore. We have developed an interactive protocol that begins with an efficient argument [IKO CCC '07] and incorporates new theoretical work to improve performance by 20+ orders of magnitude. In addition, we have broadened the computational model from Boolean circuits to a general-purpose model. We have fully implemented the system, accelerated it with GPUs, and developed a compiler that transforms computations expressed in a high-level language to executables that implement the protocol entities. The resulting system, while not quite ready for the big leagues, is close enough to practicality to suggest that in the near future, PCPs could be a real tool for building actual systems. Talk will be based on these papers and ongoing work: http://www.cs.utexas.edu/~mwalfish/papers/ginger-usec12.pdf http://www.cs.utexas.edu/~mwalfish/papers/pepper-ndss12.pd --- Michael Walfish is an assistant professor in the Computer Science Department at The University of Texas at Austin. His research interests are in systems, security, and networking. His honors include an Air Force Young Investigator Award, an NSF CAREER Award, a Sloan Research Fellowship, a Teaching Excellence Award from the UT College of Natural Sciences, the Intel Early Career Faculty Honor Program, and the UT Society for Teaching Excellence. He received his B.A. from Harvard and his Ph.D. from MIT, both in Computer Science.

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M Wawrzoniak preFPO
by Melissa M. Lawson 17 Oct '12

17 Oct '12

Michael Wawrzoniak will present his preFPO on Wednesday October 24 at 10AM in Room 402. The members of his committee are: Larry Peterson, advisor; David Blei, Andrea LaPaugh, Vivek Pai, and Rob Schapire. Everyone is invited to attend his talk. His abstract follows below. ---- The role played by data analysis and machine learning continues to gain significance in many fields, and society as a whole. In particular, statistical learning in the framework of graphical models has become a very successful and popular machine learning method used in many fields. However developing these models requires substantial expertise and applying them to very large distributed and streaming data sets can still be a very challenging problem. In this talk I will propose an architecture which will make a substantial subset of these techniques accessible to users with less expert machine learning knowledge. A framework for high-level description of models in conjugate-exponential family, automatically transforming them to distributed streaming stochastic variational inference procedure, and an evaluation platform will be outlined. The vision of this software stack is to show a possible future path for a shift from data analysis being in the hands the expert elites towards empowering the wider public. ----

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S Sevinc preFPO
by Melissa M. Lawson 15 Oct '12

15 Oct '12

Soner Sevinc will present his preFPO on Monday October 22 at 8:30 AM in Room 402. The members of his committee are: Larry Peterson (advisor), Jennifer Rexford and Andy Bavier, readers; Michael Freedman and David Walker, nonreaders. Everyone is invited to attend his talk. His abstract follows below. -------------------- "Federation Framework Discovering and authorizing resources dispersed across autonomous organizations is a challenge for federations as they scale in number of participant organizations. We first give an analysis of some of today's federations in terms of trust models and argue that complex trust models, that entail indirect trust relations, can be one way to scale federations in the future. We introduce our federation framework, which can be used to realize access control and resource discovery in federations with arbitrary complex trust models. This framework synthesizes three area of previous work; trust management systems, policy languages and resource discovery systems. CERTDIST trust management system performs access control using digital certificates for proof construction. Different from its counterparts such as ABAC or SD3, it can construct proofs for more complex trust relations, by utilizing a DHT to perform key based certificate lookup. In addition, CERTDIST's programmable credentials allow dynamic policies be expressed as digital certificates. Federation Policy Language, FPL, is used to express security and resource allocation policies in federation. FPL primitives interface to underlying CERTDIST functionality, which are used by security architects and resource providers to write policies easily. Our contract based discovery and allocation system, CODAL, performs policy-driven peer discovery and collaborative resource discovery/allocation to address two problems: (1) participants in a federation can be unknown, and (2) their resource information and policies can be private. We evaluate our design in PlanetLab, emulating a realistic federation based on PlanetLab usage logs. Results show that our system is capable of discovering and allocating resources in a large scale federation, fulfilling a request from tens of organizations. We also show allocation policies are successfully enforced by our language, and explore run-time characteristics of the FPL proof construction process, and investigate certificate retrieval in terms of time and incurred system load."

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Colloquium Speaker Phil Levis- Fri Oct 12, 3:30pm
by Nicole E. Wagenblast 11 Oct '12

11 Oct '12

Full Duplex Wireless Phil Levis , Stanford University Friday, October 12- 3:30pm Computer Science 105 Wireless networking traditionally assumes that radios are half-duplex. On a given frequency, a half-duplex radio can either transmit or receive, but not both at the same time. I present recent results demonstrating that a full-duplex radio -- a radio that can receive and transmit simultaneously on the same frequency -- can be built using commodity, off-the-shelf components. I discuss some of the possible implications of full duplex, including solving some long-standing problems in wireless, such as the hidden terminal problem, signal boosters, and access point fairness. I examine the design space for full duplex radios, describing the corresponding tradeoffs. Full duplex has the potential to revolutionize a large number of wireless systems: I'll conclude with current strengths and limitations of the technology to try to shed some light on where I think it might be most and least successful. The talk is intended for a CS audience; it does not assume any RF theory background, just a high school level understanding of the physics and mathematics of sine waves. Philip Levis is an Associate Professor of Computer Science and Electrical Engineering at Stanford University. He received his Sc.B. from Brown University in 1999, his M.S. from the University of Colorado at Boulder in 2001, and his Ph.D. from UC Berkeley in 2005. In 2008 he received an NSF CAREER award and a Microsoft Research New Faculty Fellowship. He researches the design and implementation of networked systems that interact with the world, including operating systems and protocols for embedded wireless devices, wireless mesh protocols, network infrastructure for virtual worlds, and energy efficient computing. The results of his research, including the TinyOS operating system, nesC language, Trickle algorithm, and the collection tree protocol (CTP), have been adopted by tens of thousands of users and researchers worldwide. He's authored a few Internet standards based on his work. He really likes excellent engineering and has a self-destructive aversion to low-hanging fruit.

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Colloquium Speaker Scott Klemmer- Thurs Oct 11, 4:30pm
by Nicole E. Wagenblast 11 Oct '12

11 Oct '12

The Power of Examples Scott Klemmer , Stanford University Thursday Oct 11, 4:30pm Computer Science 105 Designers in many fields rely on examples for inspiration, and examples play an important role in art and design curricula. In this talk, I'll describe several ways that examples help the creative process by illustrating concepts and alternatives. Online media offer a corpus of examples at a scale and diversity never before seen. This wealth of examples opens up new possibilities, but also poses several challenges. How can we leverage these resources? My group's research tools harvest and synthesize examples to empower more people to design interactive systems, learners to acquire new skills, experts to be more creative, and programmers to engage in more design thinking. This research shapes my project-based design teaching, which emphasizes creating diverse alternatives, self-assessment, and using examples to provide design insights and teach abstract principles. This spring, we collaborated with Coursera to launch the first massive-scale class with self and peer assessment. This enabled online students to engage in open-ended design projects, and it worked surprisingly well. Scott is an Associate Professor of Computer Science at Stanford University. He co-directs the Human-Computer Interaction Group and holds the Bredt Faculty Scholar development chair. Organizations around the world use his lab's open-source design tools and curricula; several books and popular press articles have covered his research and teaching. He has been awarded the Katayanagi Emerging Leadership Prize, Sloan Fellowship, NSF CAREER award, Microsoft Research New Faculty Fellowship. He has authored and co-authored more than 40 peer-reviewed articles; six have been awarded best paper or honorable mention at the premier HCI conferences (CHI and UIST). His former graduate students are leading professors, researchers, founders, social entrepeneurs, and engineers. He has a dual BA in Art-Semiotics and Computer Science from Brown University, Graphic Design work at RISD, and an MS and PhD in Computer Science from UC Berkeley. He serves on the editorial board of TOCHI and HCI, was the program co-chair of UIST 2011, and co-chaired the systems area of CHI 2010. He helped introduce peer assessment to open online education, and taught the first peer-assessed online course.

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