- talks - lists.cs.princeton.edu

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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R Manokaran FPO
by Melissa M. Lawson 10 Oct '12

10 Oct '12

Rajsekar Manokaran will present his FPO on Wednesday October 17 at 10 AM in Room 402. The members of his committee are: Sanjeev Arora, advisor; Moses Charikar and Zeev Dvir, readers; Mark Braverman and Rob Schapire, nonreaders. A copy of his thesis, "Approximability and Mathematical Relaxations", is on display in Room 410. Everyone is invited to attend his talk.

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V Kim preFPO
by Melissa M. Lawson 10 Oct '12

10 Oct '12

Vladimir (Vova) Kim will present his preFPO on Wednesday October 17 at 4PM in room 402. The members of his committee are: Tom Funkhouser, advisor; Szymon Rusinkiewicz and Wilmot Li (Adobe), readers; Adam Finkelstein and David Dobkin, nonreaders. Everyone is invited to attend his talk. His abstract follows below. ---------------- TITLE: Establishing Correspondences in Collections of Diverse 3D Shapes ABSTRACT: Large repositories of 3D models have become available in recent years. These repositories include scans of everyday objects and outdoor environments, CAD models created by engineers, and computer graphics models created by artists and casual users. Establishing corresponding points allows reasoning about functional and semantic similarities between models in a collection, and opens space for many applications like transferring properties, classifying and segmenting new data and exploring 3D collections. Scale of these collections necessitates development of automatic algorithms for computing such correspondences. Much of the previous work concentrates on matching pairs of shapes with limited geometric diversity. Our work addresses several challenges related to finding and representing correspondences in large collections where models exhibit substantial geometric variations including non-uniform deformations, or have different multiplicities, complexities and styles of parts. We develop algorithms that (i) handle such variations robustly, (ii) represent semantic ambiguity due to diversity of the data, and (iii) efficiently process large collections. First, to address the challenge of matching models with non-uniform deformations, we propose a fully automatic pipeline for finding an intrinsic map between two non-isometric, genus zero surfaces. Our approach is based on the observation that efficient methods exist to search for nearly isometric maps, but no single solution found with these methods provides low-distortion everywhere for pairs of surfaces differing by large deformations. To address this problem, we suggest using a weighted combination of these maps to produce a “blended map.” This approach enables algorithms that leverage efficient search procedures, yet can provide the flexibility to handle large deformations. During experiments with these methods, we find that our algorithm produces blended maps that align semantic features better than alternative approaches over a variety of data sets. Second, we propose an automatic analysis method for computing similarity relationships between points on 3D shapes across a relatively homogeneous and small collection (order of hundreds of models). Our method is robust to general geometric variations, including non-uniform deformations, and partial similarity (e.g. due to different part multiplicities or styles). We encode the inherent ambiguity in similarity relationships using fuzzy point correspondences and propose a robust and efficient computational framework that estimates fuzzy correspondences using only a sparse set of pairwise model alignments. We evaluate our analysis method on a range of correspondence benchmarks and report substantial improvements in both speed and accuracy over existing alternatives. Finally, we address the challenge of establishing correspondences in large and diverse collections (order of tens of thousands of models) efficiently and robustly. We concentrate on models that can be represented as part-wise assemblies, and our goal is to compute consistent segmentation of models along with aligning transformations between all parts, (i.e. providing a representation that can directly define point-to-point or fuzzy correspondences). We propose a method that relies on fitting a deformable template that explicitly models class-specific geometric variations. The key contribution of our approach is in iterative learning of these variations from large collections with unreliable and noisy labels, (as they appear in public repositories, such as Google Warehouse). Resulting deformable template and consistent segmentations can be used in several applications including exploring collections of shapes, synthesizing new shapes by part-wise assembly and interpreting (classifying, segmenting and reconstructing) noisy 3D scans.

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J Nelson general exam
by Melissa M. Lawson 09 Oct '12

09 Oct '12

Jude Nelson will re-present the oral exam portion of his research seminar/general exam on Tuesday October 16 at 9AM in Room 402. The members of his committee are: Larry Peterson (advisor), Michael Freedman, and Vivek Pai. Any additional faculty members wishing to attend are welcome to do so. His abstract and reading list follow below. ------------------ Abstract: It is well understood that network caches offer three potential advantages to cloud storage providers: they reduce read latency, they scale read bandwidth, and they reduce the amount of data that must be transferred directly from the datacenter (which incur some cost). Network caches "extend" cloud storage into the readers' edge networks--read requests are serviced by nearby network caches instead of upstream cloud storage. However, the same cannot be said for writers--a writer must upload data synchronously to upstream storage. Additionally, network caches may serve readers stale or even corrupt data in the presence of writes. To remedy this, we propose Syndicate--a distributed wide-area storage service that extends cloud storage to the edge of the network for both readers and writers. Syndicate provides readers the performance benefits and download transfer savings enabled by underlying CDNs and caching proxies, while at the same time guaranteeing that readers see the effects of all completed writes. It also provides writers the performance benefits of network-local storage by reducing the amount of data that must be synchronously uploaded to cloud storage on each write. Finally, by organizing data into a hierarchical namespace, and by allowing concurrent reads and writes on records while enforcing a sequential history of record creation and deletion, Syndicate provides applications with filesystem-like storage semantics similar to many existing cloud storage services. Syndicate makes two contributions over existing wide-area storage systems. First, it simultaneously leverages CDNs and other edge caches while also supporting a well-defined consistency model in the face of writes. Second, it uses a ``built from parts'' design strategy, whereby Syndicate is effectively layered on top of a disparate set of commodity components. Syndicate manages naming and consistency, existing cloud storage services enhance data persistence, and unmodified CDNs offer the performance and cost advantages outlined above. Reading list: Peterson, Larry L., and Davie, Bruce S. "Computer Networks, a Systems Approach. 4th Ed." Cerf, V., and Kahn, R. "A Protocol for Packet Network Intercommunication." Lamport, L. "Time, clocks, and the ordering of events in a distributed system." Schneider, F. "Implementing Fault-Tolerant Services Using the State Machine Approach: A Tutorial" Park, K. and Pai, V. "Scale and Performance in the CoBlitz Large-File Distribution Service." L. Wang, V. Pai, and Peterson, L. "The Effectiveness of Request Redirection on CDN Robustness." Annapureddy, S., Freedman, M., and Mazieres, D. "Shark : Scaling File Servers via Cooperative Caching." Burrows, M. "The Chubby lock service for loosely-coupled distributed systems." Peterson, L., Bavier, A., Fiuczynski, M., Muir, S. "Experineces Building PlanetLab." Belaramani, N., Dahlin, M., Gao, L., et. al. "PRACTI Replication." Stribling, J., Sovran, Y., Zhang, I., et. al. "Flexible , Wide-Area Storage for Distributed Systems with WheelFS." Freedman, M., Freudenthal, E., Mazieres, D. "Democratizing content publication with Coral." Vahdat, A., Eastham, P., Yoshikawa, C., et. al. "WebOS: Operating System Services for Wide Area Applications."

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S Ghosh general exam
by Melissa M. Lawson 08 Oct '12

08 Oct '12

Soumyadeep Ghosh will re-present his research seminar/general exam on Monday October 15 at 8AM in Room 402. The members of his committee are: David August (advisor), Andrew Appel, and Margaret Martonosi. Everyone is invited to attend his talk, and those faculty wishing to remain for the oral exam following are welcome to do so. His abstract and reading list follow below. ------- A Low-Overhead Framework for Partial Memory Safety Attacks that violate memory safety to corrupt program state form a large class of security threats. In a type-unsafe language such as C, such attacks can be used to cause program crash, leak privileged information, and inject malicious code. These vulnerabilities often stem from exploitation of program behavior that is undefined in the C standard. Write Integrity Testing (WIT) is a technique that provides partial memory safety, by inserting low-cost runtime checks to enforce only those program behaviors that are defined by the C standard. In this work, we present modifications that extend WIT’s coverage to protect both integrity and confidentiality of memory accesses, at minimal performance costs. We evaluate the performance of the modified framework and also demonstrate the effectiveness of our system in detecting a number of real-world attacks. Reading List: Textbooks: [1] A. W. Appel. Modern Compiler Implementation in C. Cambridge University Press, 1998. [2] J. L. Hennessy and D. A. Patterson. Computer Architecture, Fourth Edition: A Quantitative Approach. Morgan Kaufmann Publishers Inc., 2006. Papers: [1] P. Akritidis, C. Cadar, C. Raiciu, M. Costa, and M. Castro. Preventing memory error exploits with WIT. In Proceedings of the 2008 IEEE Symposium on Security and Privacy, 2008. [2] D. Avots, M. Dalton, V. B. Livshits, and M. S. Lam. Improving software security with a C pointer analysis. In ICSE, 2005. [3] S. Chen, J. Xu, E. C. Sezer, P. Gauriar, and R. K. Iyer. Non-control-data attacks are realistic threats. In Proceedings of the 14th conference on USENIX Security Symposium - Volume 14, 2005. [4] D. Dhurjati, S. Kowshik, V. Adve, and C. Lattner. Memory safety without runtime checks or garbage collection. In LCTES, 2003. [5] M. Hind. Pointer analysis: Haven’t we solved this problem yet? In 2001 ACM SIGPLAN-SIGSOFT Workshop on Program Analysis for Software Tools and Engineering (PASTE’01), 2001. [6] T. Jim, J. G. Morrisett, D. Grossman, M. W. Hicks, J. Cheney, and Y. Wang. Cyclone: A safe dialect of C. In USENIX Annual Technical Conference, 2002. [7] S. Nagarakatte, J. Zhao, M. M. Martin, and S. Zdancewic. Softbound: highly compatible and complete spatial memory safety for C. In Proceedings of PLDI, 2009. [8] G. C. Necula, S. McPeak, and W. Weimer. Ccured: type-safe retrofitting of legacy code. In Proceedings of POPL, 2002. [9] E. Suh, J. W. Lee, and S. Devadas. Secure program execution via dynamic information flow tracking. In Proceedings of ASPLOS, 2004. [10] E. Witchel, J. Cates, and K. Asanovic. Mondrian memory protection. In Proceedings of ASPLOS, 2002.

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J Terrace FPO
by Melissa M. Lawson 08 Oct '12

08 Oct '12

Jeff Terrace will present his FPO on Friday October 12 at 1PM in Room 302 (note room!). The members of his committee are: Michael Freedman, advisor; Adam Finkelstein and Phil Levis (Stanford), readers; Vivek Pai and Szymon Rusinkiewicz, nonreaders. A copy of his thesis, "Content Conditioning and Distribution for Dynamic Virtual Worlds", is on display in Room 310. Everyone is invited to attend his talk.

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A Badam FPO
by Melissa M. Lawson 01 Oct '12

01 Oct '12

Anirudh Badam will present his FPO on Thursday October 4 at 2PM in Room 301 (note room!!). The members of his committee are: Vivek Pai, advisor; Michael Freedman and Jen Rexford, readers; David Walker and Andrea LaPaugh, nonreaders. A copy of his thesis, "Bridging the Memory- Storage Gap" is on display in Room 310. Everyone is invited to attend his talk.

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Colloquium Speaker Hyesoon Kim Oct 3
by Nicole E. Wagenblast 01 Oct '12

01 Oct '12

When GPUs meet CPUs: opportunities, challenges and solutions in heterogeneous architectures Hyesoon Kim , Georgia Institute of Technology Wednesday, October 3, 2012- 4:30pm Computer Science Small Auditorium, 105 The last decade has seen a paradigm shift in the architecture of computing platforms: Uni-processors have given way to multi-core (many-core) processors, and now the industry is moving toward heterogeneous architectures that combine CPUs and GPUs on the same chip, as we can see from Intel, AMD, NVIDIA, etc. Heterogeneous architectures are especially attractive as they can provide high performance and energy-efficiency for both general-purpose applications as well as high throughput applications. However, these architectures introduce several new challenges: including programming, determining power and performance trade-offs and developing hardware solutions that exploit the underlying heterogeneity. In this talk I will present some of our recent work that reduces the software effort required in programming such architectures, and provides hints to estimate the performance and power behavior of CPUs , GPUs or CPUs+GPUs. I will also discuss architecture solutions that improve overall system performance by taking into account the difference in characteristics of CPU and GPU applications, and optimizing the cache partitioning, prefetching, and DRAM scheduling to best suit the workload needs. Hyesoon Kim is an Assistant professor in the School of Computer Science at Georgia Institute of Technology. Her research interests include high-performance energy-efficient heterogeneous architectures, programmer-compiler-microarchitecture interaction and developing tools to help parallel programming. She received a BA in mechanical engineering from Korea Advanced Institute of Science and Technology (KAIST), an MS in mechanical engineering from Seoul National University, and an MS and a Ph.D in computer engineering at The University of Texas at Austin. She is a recipient of the NSF career award in 2011.

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Canturk Isci seminar. Today at 12:30pm in CS302.
by Margaret Martonosi 25 Sep '12

25 Sep '12

Reminder: Dr. Canturk Isci from IBM Research will be speaking here today (Tuesday Sept 25) at 12:30pm in CS 302. Virtualization Management and Data Center Monitoring for Energy-efficient Clouds Canturk Isci IBM Research Abstract: Energy and thermal management in the cloud has become a primary concern as the global footprint of large-scale compute systems reaches significant levels, and continues to increase with impressive pace, following the ever-increasing compute demand and data explosion. Various new control knobs across systems, middleware, virtualization and facilities levels promote many interesting optimization opportunities for improving energy efficiency. However, these are coupled with significant management and monitoring challenges for effectively exploiting the present opportunities. In this talk we first look at some of the potential opportunities and emerging challenges for improving the energy-efficiency in clouds, and highlight our research at virtualization, distributed systems and data center levels targeting these opportunities and challenges. We describe an effective distributed resource management approach based on a novel, black-box virtual machine (VM) demand estimation technique, which serves as a key enabler for improving the energy efficiency of virtualized systems via consolidation-driven, dynamic VM placement. We demonstrate that this demand estimation technique is highly-general across virtualization technologies and can very accurately track actual VM demands even under extreme consolidation and resource constraints. With multiple real-system prototypes, we present the dramatic improvements in the performance and agility of energy-aware virtualization management when guided by demand estimation. Next, we briefly look at the increasing cost and complexity of monitoring in the cloud and describe a new approach based on mobile, autonomous robots for reliable, fast and cost-effective monitoring and management in data centers. We demonstrate the operation principles of actual robot prototypes that are deployed in various live data centers, and discuss their applications to predictive and diagnostic analytics for energy, thermal and asset management. Bio: Canturk Isci is a Research Staff Member in IBM TJ Watson Research Center. His research interests include virtualization, data center energy and thermal management, microarchitectural and system-level techniques for energy-efficient and adaptive computing. Prior to joining IBM Research, Canturk was a Senior Member of Technical Staff at VMware, where we he worked on distributed resource and power management, performance and scalability of virtualized systems. He is the recipient of a best paper award in ICAC 2011, best research poster in VMworld 2008 and academic fellowships from British Council, Princeton and Bilkent University. He serves as the industry chair in IEEE Computer Society, Special Technical Community on Sustainable Computing. Canturk has a B.S. in Electrical Engineering from Bilkent University, an M.Sc. with Distinction in VLSI System Design from University of Westminster, and a Ph.D. in Electrical Engineering from Princeton University. Margaret Martonosi Professor, Dept. of Computer Science Princeton University http://www.princeton.edu/~mrm mrm(a)princeton.edu

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