- talks - lists.cs.princeton.edu

L Luo preFPO
by Melissa M. Lawson 06 Dec '12

06 Dec '12

Linjie Luo will present his preFPO on Thursday December 13 at 11AM in Room 402. The members of his committee are: Szymon Rusinkiewicz, advisor; Tom Funkhouser and Sylvain Paris (Adobe), readers; Adam Finkelstein and David Dobkin, nonreaders. Everyone is invited to attend his talk. His abstract follows below. --- Title: Towards High Quality Hair Capture and Modeling Abstract: Hair is one of human's most distinctive features and one important component in human digitalization. However, capturing and modeling hair remains challenging because of hair's unique properties: the specular appearance violates the Lambertian surface assumption used in most multi-view stereo reconstruction methods; The vast variations and complex topology of hair styles pose great technical difficulties for high quality hair capture and modeling. We propose an orientation-based matching metric for multi-view hair capture that is more robust to hair's view-dependent specular highlights. The metric is performed in multi-resolution to reveal increasing hair structures and details. The orientation-based metric also facilitates the structure-aware aggregation to reduce matching error and stereo noise along coherent hair structures. Our approach is able to reconstruct approximate surfaces to a variety of hair styles with detailed hair structures from ~30 input views. To alleviate the requirement for dense small-baseline capture setup, we introduce a visual hull based refinement method to enable wide-baseline full hair capture with only 8 views. The refinement is driven by the strands generated from the orientation map of each input view. The final shape is obtained by optimizing the orientation consistency of these strands against all the orientation maps as well as the regularization terms that account for the smoothness at strand, wisp and global levels. We find our method effective on various hair styles and suitable for dynamic hair capture. We achieve an average reconstruction accuracy of ~3mm on synthetic datasets. Finally, we address the challenge of robustly modeling hair strands from the captured incomplete exterior hair geometry with plausible topology for hair simulation. Our main contribution is the construction and analysis of the global connection graph to compute the plausible hair topology from the incomplete exterior hair geometry. The connection graph encodes coherent local strands and plausible inter-strand connections. The final hair strands can be generated from a wisp forest derived from the connection graph.

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Systems Lunch Talk Matt Welsh, Friday (Dec 5) at 12:30pm
by Mike Freedman 05 Dec '12

05 Dec '12

This Friday at 12:30pm (lunch starts at 12:00pm) in Room 302, Matt Welsh will be talking about his experience "making the mobile web faster" at Google. --- Making the Mobile Web Fast Matt Welsh, Google Inc. Web usage on mobile devices is exploding, and in many countries, mobile devices are the predominant means of accessing the Internet. But the mobile web is still incredibly slow; clearly the web was not designed for mobile networks. Our team at Google is working to solve this problem, by optimizing all layers of the stack: device operating systems, browsers, network protocols, servers, and web content. In this talk, I'll talk about why the mobile web is slow, provide some insight into the inner workings of 3G and 4G networks, and provide an overview of some of our efforts to make the mobile web fast. I'll also talk a bit about what it was like to make the leap from academia to industry. Matt Welsh is the head of mobile web performance at Google. Prior to joining Google, he was a professor of Computer Science at Harvard, where he worked on projects ranging from deploying wireless sensor networks on volcanoes in Ecuador to building a swarm of robotic bees. He did his PhD at UC Berkeley.

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Fwd: Zack Ives talk on Wednesday
by Ariel Rabkin 05 Dec '12

05 Dec '12

Hi all. Reminder. This talk is today at 12:30 -- food beforehand. --Ari ---------- Forwarded message ---------- From: Ariel Rabkin <asrabkin(a)cs.princeton.edu> Date: Mon, Dec 3, 2012 at 6:03 PM Subject: Zack Ives talk on Wednesday To: ens(a)lists.cs.princeton.edu Zack Ives is visiting us from UPenn. He will be giving a lunch-time (12:30) talk in rm 302 on December 5. Let me know if you want to meet with him. ASPEN: Seamless Declarative Programming across Sensors, Streams, and the Cloud Due to advances in semiconductor and communications technology, we are steadily moving towards a world filled with a plethora of embedded sensing devices as well as "virtual" sensors within devices -- with the potential to monitor the environment and to react to or even anticipate changes. The environment being monitored might be a smart hospital, an entire campus, or even an office or data center. Often the behaviors we wish to produce involve combining constantly updating (streaming) data from multiple heterogeneous sensor and Internet sources. A major challenge is how to manage the resulting complexity, and to build large-scale, rich monitoring, learning, and control applications. In the ASPEN project we have been exploring an approach that seeks to separate logical dataflow from most of the algorithmic logic -- using a declarative, SQL-like (but iterative and incremental) programming model to capture the dataflow, data transformation, and state management needed by an application, combined with small bits of procedural code to handle complex logic. Our platform provides distributed query optimization that takes runtime conditions into account, while also supporting a range of learning, prediction, and connection-finding algorithms. In this talk I will describe our basic ASPEN prototype including cluster and sensor subsystems, and provide an overview of how we address issues of query optimization, distributed query execution, and incremental recomputation. Work done jointly with Mengmeng Liu, Svilen Mihaylov, Boon Thau Loo, and Sudipto Guha Zachary Ives is an Associate Professor and the Markowitz Faculty Fellow at the University of Pennsylvania. His research interests include data integration and sharing, "big data", sensor networks, and data provenance and authoritativeness. He is a recipient of the NSF CAREER award, and an alumnus of the DARPA Computer Science Study Panel and Information Science and Technology advisory panel. He has also been awarded the Christian R. and Mary F. Lindback Foundation Award for Distinguished Teaching. He serves as the undergraduate curriculum chair for Penn's Singh Program in Market and Social Systems Engineering. He is a co-author of the textbook Principles of Data Integration.

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W Lloyd preFPO
by Melissa M. Lawson 04 Dec '12

04 Dec '12

Wyatt Lloyd will present his preFPO on Tuesday December 11 at 9AM in Room 402. The members of his committee are; Michael Freedman, advisor; Vivek Pai and David Andersen (CMU), readers; Jennifer Rexford and Margaret Martonosi, nonreaders. Everyone is invited to attend his talk. His abstract follows below. ------------------------------ Title: Stronger Consistency and Semantics for Low-Latency Geo-Replicated Storage Abstract: Distributed data stores that support complex online applications, such as social networks, are built with a two-level architecture. Data is replicated across a small number of datacenters and within each datacenter is stored in clusters of thousands or more machines. These two levels bring different challenges for creating a scalable, responsive, and consistent data store. Our COPS system is the first distributed data store to guarantee the ALPS properties—availability, low latency, partition tolerance, and scalability—and achieve consistency stronger than eventual. Eventual consistency specifies only that writes in one datacenter eventually show up in the others. Causal consistency, which is what COPS provides, maintains the partial order over operations establish by potential causality. Under causal consistency, all of a user’s operations appear in the order they are issued and interactions between users, e.g., conversations in comments, appear in their correct order as well. This improvement in consistency gives users a better experience and makes the data store easier for programmers to reason about. The key technical contribution of the COPS work is its fully distributed and scalable architecture that uses explicit metadata and off-path dependency checks to enforce ordering instead of relying on any single point of coordination. Our Eiger system pushes on the semantics an ALPS data store can provide. Eiger provides high-performance, guaranteed low-latency read-only and write-only transactions across all the machines in a cluster. Read-only transactions allow a client to observe a consistent snapshot of an entire cluster. Write-only transactions allow clients to atomically write many values spread across many servers at a single point in time. One important use case for write-only transaction is maintaing symmetrical relationships, e.g., Alice “isAFriendOf” Bob and Bob “isAFriendOf” Alice should both appear or disappear at the same time. Eiger also improves the semantics of ALPS data stores by providing the Column-Family data model—which is used in BigTable and Cassandra, and can be used to built real applications like Facebook—instead of the key-value data model provided by COPS—which is useful mainly as an opaque cache.

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Colloquium Speaker Juan Bello Friday Nov 30, 3:30pm
by Nicole E. Wagenblast 29 Nov '12

29 Nov '12

Information Extraction from Music Audio Juan Bello , New York University Friday, November 30, 3:30pm Computer Science 105 This talk discusses a mix of concepts, problems and techniques at the crossroads of signal processing, machine learning and music. I will start by motivating the use of content-based methods for the analysis and retrieval of music. Then, I will introduce work in three projects being investigated in my lab: automatic chord recognition using hidden Markov models, music structure analysis using probabilistic latent component analysis, and feature learning using convolutional neural networks. In the process of doing so, I hope to illustrate some of the challenges and opportunities in the field of music informatics. Juan Pablo Bello is an Associate Professor of Music Technology at New York University. In 1998 he received his BEng in Electronics from the Universidad Simón Bolívar in Caracas, Venezuela, and in 2003 he earned a doctorate in Electronic Engineering at Queen Mary, University of London. Juan teaches and researches on the computer-based analysis of musical signals and its applications to music information retrieval, digital audio effects and interactive music systems. He is the principal investigator of the music informatics group of the Music and Audio Research Lab (MARL) at NYU. For more information please visit: https://files.nyu.edu/jb2843/public/ http://marl.smusic.nyu.edu/

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Distinguished Colloquium Speaker Dan Spielman Thurs Nov 29 4:30pm
by Nicole E. Wagenblast 29 Nov '12

29 Nov '12

Algorithms, Graph Theory, and the Solution of Laplacian Linear Equations Dan Spielman , Yale University Thursday, November 29, 4:30pm Computer Science 105 We survey several fascinating concepts and algorithms in graph theory that arise in the design of fast algorithms for solving linear equations in the Laplacian matrices of graphs. We will begin by explaining why linear equations in these matrices are so interesting. The problem of solving linear equations in these matrices motivates a new notion of what it means for one graph to approximate another. This leads to the problem of approximating graphs by sparse graphs. Our algorithms for solving Laplacian linear equations will exploit surprisingly strong approximations of graphs by sparse graphs, and even by trees. We will survey the roles that spectral graph theory, random matrix theory, graph sparsification, low-stretch spanning trees and local clustering algorithms play in the design of fast algorithms for solving Laplacian linear equations. Daniel Alan Spielman received his B.A. in Mathematics and Computer Science from Yale in 1992, and his Ph.D in Applied Mathematics from M.I.T. in 1995. He spent a year as a NSF Mathematical Sciences Postdoc in the Computer Science Department at U.C. Berkeley, and then taught in the Applied Mathematics Department at M.I.T. until 2005. Since 2006, he has been a Professor at Yale University. He is presently the Henry Ford II Professor of Computer Science, Mathematics, and Applied Mathematics. He has received many awards, including the 1995 ACM Doctoral Dissertation Award, the 2002 IEEE Information Theory Paper Award, the 2008 Godel Prize, the 2009 Fulkerson Prize, the 2010 Nevanlinna Prize, an inaugural Simons Invesigator Award, and a MacArthur Fellowship. He is a Fellow of the Association for Computing Machinery and a member of the Connecticut Academy of Science and Engineering. His main research interests include the design and analysis of algorithms, graph theory, machine learning, error-correcting codes and combinatorial scientific computing.

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Zach Ives visiting
by Ariel Rabkin 26 Nov '12

26 Nov '12

Hi All. Professor Zachary Ives is visiting us from the University of Pennsylvania. He will be giving a talk about his work in room 302 at 12:30 on December 5. The talk will be about ASPEN: Seamless Declarative Programming across Sensors, Streams, and the Cloud. Abstract: Due to advances in semiconductor and communications technology, we are steadily moving towards a world filled with a plethora of embedded sensing devices as well as "virtual" sensors within devices -- with the potential to monitor the environment and to react to or even anticipate changes. The environment being monitored might be a smart hospital, an entire campus, or even an office or data center. Often the behaviors we wish to produce involve combining constantly updating (streaming) data from multiple heterogeneous sensor and Internet sources. A major challenge is how to manage the resulting complexity, and to build large-scale, rich monitoring, learning, and control applications. In the ASPEN project we have been exploring an approach that seeks to separate logical dataflow from most of the algorithmic logic -- using a declarative, SQL-like (but iterative and incremental) programming model to capture the dataflow, data transformation, and state management needed by an application, combined with small bits of procedural code to handle complex logic. Our platform provides distributed query optimization that takes runtime conditions into account, while also supporting a range of learning, prediction, and connection-finding algorithms. In this talk I will describe our basic ASPEN prototype including cluster and sensor subsystems, and provide an overview of how we address issues of query optimization, distributed query execution, and incremental recomputation. Work done jointly with Mengmeng Liu, Svilen Mihaylov, Boon Thau Loo, and Sudipto Guha Speaker bio: Zachary Ives is an Associate Professor and the Markowitz Faculty Fellow at the University of Pennsylvania. His research interests include data integration and sharing, "big data", sensor networks, and data provenance and authoritativeness. He is a recipient of the NSF CAREER award, and an alumnus of the DARPA Computer Science Study Panel and Information Science and Technology advisory panel. He has also been awarded the Christian R. and Mary F. Lindback Foundation Award for Distinguished Teaching. He serves as the undergraduate curriculum chair for Penn's Singh Program in Market and Social Systems Engineering. He is a co-author of the textbook Principles of Data Integration.

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4:30pm Mon Nov 26 talk on "Software-based services for cloud networks" in CS 402
by Jennifer Rexford 21 Nov '12

21 Nov '12

Software-based Services for Cloud Networks Anees Shaikh, IBM Research Monday, November 26, 2012, 4:30 PM - 5:30 PM Computer Science 402 Software-defined networking (SDN) aims to provide a well-defined programming and automation interface to network devices. In moving network control and functionality to software running on standard server platforms, SDNs depart from the traditional, vertically integrated model of network hardware and software. We view SDNs as a new opportunity for supporting more seamless integration of networks with IT processes, and for providing higher-value network services. In this talk, after describing the SDN model and our approach for building SDNs, we will focus on the problem of providing networking services for cloud computing platforms. As more enterprises look to leverage the cost and flexibility advantages of cloud computing, the lack of rich networking support remains a challenge. We will discuss the requirements of enterprise line-of-business applications for additional network functions in the cloud, and describe our research efforts to develop networking services for multi-tenant enterprise clouds using software-defined networking techniques. Anees Shaikh is a Research Staff Member and Manager with the IBM TJ Watson Research Center in New York. He currently leads the Systems Networking Research group at Watson, focusing on problems related to data center and cloud networks. www: http://researcher.ibm.com/researcher/view.php?person=us-aashaikh

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Distinguished Colloquium Speaker Eva Tardos Monday Nov 19 4:30pm
by Nicole E. Wagenblast 19 Nov '12

19 Nov '12

How to Design Simple Efficient Mechanisms that are also Composable Eva Tardos , Cornell University Monday, November 19, 2012 , 4:30 PM - 5:30 P M Computer Science 105 E-commerce applications require simple, and well-designed systems, and systems that work well even if users participate in multiple mechanisms (and the value of each player overall is a complex function of their outcomes). Traditional mechanism design has considered such mechanisms only in isolation, and the mechanisms it proposes tend to be complex and impractical. In contrast, players typically participate in various mechanisms, mechanisms that are run by different principals (e.g. different sellers on eBay or different ad-exchange platforms) and coordinating them to run a single combined mechanism is infeasible or impractical. Even the simple and elegant Vickrey auction loses some of its appeal when not in isolation: when the overall value of each player is a complex function of their outcomes, the global mechanism is no longer truthful. In this talk we initiate the study of efficient mechanism design with guaranteed good properties even when players participate in multiple different mechanisms either simultaneously or sequentially. Over the last decade, computer scientists and game theorists have developed good understanding of the impact of strategic user behavior on system performance in environments that include selfish traffic routing, service location, and bandwidth sharing. We will consider simple mechanisms from this perspective. We define smooth mechanisms (that can be thought of as mechanisms that generate approximately market clearing prices), and show that smooth mechanisms are approximately efficient, and the efficiency guarantees for smooth mechanisms (when studied in isolation) carry over to the same or approximately the same guarantees for a market composed of such mechanisms. Joint work with Vasilis Syrgkanis. Eva Tardos is a Jacob Gould Schurman Professor of Computer Science at Cornell University, is Senior Associate Dean of Computing and Information Science, and was department chair 2006-2010. She received her PhD from Eotvos University in Budapest. She has been elected to the National Academy of Engineering and the American Academy of Arts and Sciences, and is the recipient of some fellowships and awards, including the Packard Fellowship, the Fulkerson Prize and the Dantzig prize. She was editor in chief of SIAM Journal of Computing 2003-09, and is editor of several other journals, including the Journal of the ACM, and Combinatorica. Her research interest is algorithms and algorithmic game theory, the subarea theory of designing systems and algorithms for selfish users.

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Colloquium Speaker Ken Birman, Tues Nov. 13, 4:30pm
by Nicole E. Wagenblast 13 Nov '12

13 Nov '12

What are the Right Roles for Formal Methods in High Assurance Cloud Computing? Ken Birman , Cornell University Tuesday, November 13, 2012- 4:30pm Computer Science 105 The developer of a high assurance system must justify the fitness of the system for the intended use. In "small" scenarios, this problem is well understood: it entails rigorously specifying properties the system must achieve, designing protocols and correctness proofs, and then implementing and testing the needed code. In scaled-out settings, complex architectures are often unavoidable and this methodology can no longer be used. This talk focuses on how the resulting problems play out in the context of Isis2 (isis2.codeplex.com), a new system I've been building that supports a wide range of high-assurance properties for applications that will be hosted on cloud computing datacenters, and hence might need to run at very ambitious scale. We'll see that while it is possible to create systems of these kinds, existing formal methods are ill-suited to reasoning about the resulting solutions, suggesting that additional work will be needed to bridge between the mathematical and scientific foundations of high assurance of the kinds we teach in academic settings and the real-world instances of such problems that we may face in the near future. Ken Birman is the N. Rama Rao Professor of Computer Science at Cornell University, where he has headed a research effort in the area of high assurance distributed computing for thirty years. Ken is best known for inventing the virtual synchrony computing model and building the Isis Toolkit, which was ultimately used to build the system that operated the New York Stock Exchange for more than a decade, and the systems that continue to operate the French Air Traffic Control system and the US Navy AEGIS today. He also pioneered in the use of gossip protocols for system monitoring, management and control; several of his solutions are used today in the platforms that operate today's largest cloud computing infrastructures, notably at Amazon, IBM and Microsoft. A Fellow of the ACM since 1999, Ken won the 2009 IEEE Kanai Award for his research in distributed systems. He is currently developing online instructional materials for a short course on building high assurance cloud computing systems using his Isis2 platform.

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