Colloquia and Seminars

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Computer Science events calendar in HTTP ICS format for of Google calendars, and for Outlook.

Academic Calendar at Technion site.

Upcoming Colloquia & Seminars

  • Coding Theory: Cyclic Subspace Codes from Sidon Sets

    Speaker:
    Netanel Raviv (CS, Technion)
    Date:
    Sunday, 4.12.2016, 14:30
    Place:
    Taub 601

    The interest in subspace codes has increased recently due to their application in error correction for random network coding. In order to study their properties and find good constructions, the notion of cyclic subspace codes was introduced by using the extension field structure of the ambient space. However, to this date there exists no general construction with a known relation between k, the dimension of the codewords, and n, the dimension of the entire space.

    In this talk we present a construction of a full orbit cyclic subspace code in which n is quadratic in k. This construction is based on Sidon sets, which are sets of integers in which all pairwise sums are distinct. We prove the existence of a full orbit code where n is linear in k, and show that any such code induces a Sidon set. Finally, we show a surprising application of our techniques for devising a private-key cryptosystem, and lay the grounds for a public-key one.

  • Market Driven Queuing

    Speaker:
    Boris Pismenny, M.Sc. Thesis Seminar
    Date:
    Monday, 5.12.2016, 15:30
    Place:
    Taub 301
    Advisor:
    Prof. Assaf Schuster and Dr. Orna Agmon Ben-Yehuda

    Network providers must dynamically allocate scarce physical resources among their clients to maximize benefit. Network pricing is one way for providers to maximize client benefit by allowing them to share available bandwidth according to their willingness to pay for it. The resulting allocation grants additional bandwidth to those who need it the most, while decreasing the bandwidth of those who need it the least. Existing queueing algorithms use the results of pricing schemes as weights for sharing bandwidth, which can change only in response to a change in client willingness to pay. However, network congestion, jitter and failures affecting a flow create excess bandwidth that could be used by another flow. Queueing algorithms that can share the excess bandwidth are called work-conserving. Network pricing schemes traditionally ignore work conservation, by assuming that all clients are constantly backlogged. In this paper, we design and evaluate the Market Driven Queueing (MDQ) algorithm. By combining a queueing algorithm with a bandwidth pricing mechanism, MDQ provides the benefits of both. As a work-conserving algorithm, MDQ maximizes client benefit while improving utilization. Moreover, it requires only O(log(n)) processing time per packet, where n is the number of active flows. We analyse the properties of MDQ and evaluate it using simulation. Our simulation results show that MDQ improves clients’ aggregated benefit by up to 4x compared to state-of-the-art combinations of pricing and queueing algorithms. MDQ is also applicable to other scheduling problems such as distributed queues or I/O queue scheduling.

  • Pixel Club: Signal Modeling: From Convolutional Sparse Coding to Convolutional Neural Networks

    Speaker:
    Vardan Papyan​ (CS, Technion)
    Date:
    Tuesday, 6.12.2016, 11:30
    Place:
    Room 337 Taub Bld.

    Within the wide field of sparse approximation, convolutional sparse coding (CSC) has gained increasing attention in recent years. This model assumes a structured-dictionary built as a union of banded Circulant matrices. Most attention has been devoted to the practical side of CSC, proposing efficient algorithms for the pursuit problem, and identifying applications that benefit from this model. Interestingly, a systematic theoretical understanding of CSC seems to have been left aside, with the assumption that the existing classical results are sufficient.

    In this talk we start by presenting a novel analysis of the CSC model and its associated pursuit. Our study is based on the observation that while being global, this model can be characterized and analyzed locally. We show that uniqueness of the representation, its stability with respect to noise, and successful greedy or convex recovery are all guaranteed assuming that the underlying representation is locally sparse. These new results are much stronger and informative, compared to those obtained by deploying the classical sparse theory.

    Armed with these new insights, we proceed by proposing a multi-layer extension of this model, ML-CSC, in which signals are assumed to emerge from a cascade of CSC layers. This, in turn, is shown to be tightly connected to Convolutional Neural Networks (CNN), so much so that the forward-pass of the CNN is in fact the Thresholding pursuit serving the ML-CSC model. This connection brings a fresh view to CNN, as we are able to attribute to this architecture theoretical claims such as uniqueness of the representations throughout the network, and their stable estimation, all guaranteed under simple local sparsity conditions. Lastly, identifying the weaknesses in the above scheme, we propose an alternative to the forward-pass algorithm, which is both tightly connected to deconvolutional and recurrent neural networks, and has better theoretical guarantees.

    ​​Short bio:
    Vardan Papyan received the B.Sc. degree from the Department of Computer Science, Technion– Israel Institute of Technology, in 2013, where he is currently pursuing his Ph.D. degree. His research interests include signal and image processing, deep learning and its relation to sparsity-based modeling of signals.

  • Finding Security Vulnerabilities in Network Protocols Using Methods of Formal Verification

    Speaker:
    Adi Sosnovich, Ph.D. Thesis Seminar
    Date:
    Wednesday, 7.12.2016, 15:30
    Place:
    Taub 601
    Advisor:
    Prof. Orna Grumberg

    The Internet infrastructure relies almost entirely on network protocols that are based on open standards. However, the majority of network devices on the Internet, e.g. routers and switches, are proprietary and closed source. Hence, there is no straightforward way to analyze them. Specifically, one cannot easily and systematically identify deviations of a network device's protocol implementation from the protocol's standard. Such deviations may degrade the security or resiliency of the network. In this talk I will present our work on a formal analysis of black boxes in the network. We develop a formal black-box method to unearth non-standard protocol deviations in closed-source network devices. The method relies only on the ability to test the targeted protocol implementation and observe its output. We use a model-based testing approach, which relies on a formal model of the protocol in question. We develop optimizations that are tailored to the analysis of network protocols, to allow reducing the number of generated tests without loss of functionality cover of the model. We evaluate our method against the OSPF protocol. We search for deviations in the OSPF implementation of Cisco - the largest networking vendor in the world. Our evaluation identified numerous significant deviations. Some of them can be abused to compromise the security of a network. The deviations were acknowledged by Cisco to exist in the versions we tested. I will briefly describe other topics in my thesis.

  • CGGC Seminar: OpenMP - In Practice

    Speaker:
    Boaz Sternfeld (CS, Technion)
    Date:
    Sunday, 11.12.2016, 13:30
    Place:
    Room 337-8 Taub Bld.

    OpenMP is an API for writing multithreaded, shared memory parallelism, it consists of a set of compiler directives none intrusive to the original serial code. In addition I shall present parfor concept in MATLAB which is useful where you need many loop iterations of a simple calculation.

  • Pixel Club: Arranging & Improving Photos

    Speaker:
    Ohad Fried (Princeton)
    Date:
    Sunday, 11.12.2016, 14:30
    Place:
    EE Meyer Building 1061

    There are *many* photos in the world. An average user might have thousands of photos in their personal photo collection. We have reached a point where photo acquisition is trivial, and the next challenge lies in arranging and easily editing such large photo collections. I will start the talk by briefly surveying a few of our works that aim to arrange large collections, and to provide fast (yet sophisticated) image manipulation techniques. Next, I will describe a new type of photo elements: “distractors” and explain how those are related yet different from saliency, and how we can automatically detect them. Lastly, I will present our latest work that can fix perspective distortions in portrait photos.​​

    Bio:
    Ohad Fried is a PhD student in the Computer Science Department at Princeton University. His work lies in the intersection of computer graphics, computer vision, and HCI. Previously, he received an M.Sc. in Computer Science and a B.Sc. in Computational Biology from The Hebrew University. Ohad’s research focuses on tools, algorithms, and new paradigms for photo editing. He published research papers in premier venues, including SIGGRAPH, CVPR, Eurographics, and NIME. Ohad is the recipient of several awards, including a Siebel Scholarship, a Google PhD Fellowship and a Princeton Gordon Y.S. Wu Fellowship in Engineering. If you own a cable modem, there’s a non-negligible chance that Ohad’s code runs within it, so feel free to blame him for your slow internet connection. www.ohadf.com

  • Linear and Generalized Linear Mixed Models for Genetic Case Control Studies

    Speaker:
    Omer Weissbrod, Ph.D. Thesis Seminar
    Date:
    Wednesday, 14.12.2016, 13:00
    Place:
    Taub 601
    Advisor:
    Prof. Dan Geiger and Prof. Saharon Rosset

    In recent years, genetic studies have revolutionized our understanding of common diseases like diabetes and cancer. However, the analysis of genetic studies of disease poses substantial statistical and computational challenges, owing to the data collection scheme and to the extremely large data dimensionality. We propose a unified modeling framework that addresses these challenges in order to solve the three main problems associated with genetic disease studies: Searching for disease causing mutations, predicting risk of being affected with a disease, and inferring the overall genetic architecture of diseases. Our proposed solutions are based on generalized linear mixed models, and employ techniques from diverse fields, such as multiple kernel learning from machine learning and the method of moments from statistics. The proposed methodologies lead to state of the art results in the three main problems of genetic studies of disease, and have been published in top scientific journals. The talk is aimed towards a general audience, and does not require statistical or biological background.

  • Cloud resource provisioning for social notifications at mass scale

    Speaker:
    Roman Vitenberg - COLLOQUIUM LECTURE
    Date:
    Thursday, 15.12.2016, 14:30
    Place:
    Room 337 Taub Bld.
    Link:
    http://www.cs.technion.ac.il/~colloq/20161215_14_30_Vitenberg.html
  • A Workshop in Honor of Prof. Johann Makowsky’s Retirement

    A Workshop in Honor of Prof. Johann Makowsky’s Retirement

    Date:
    Sunday, 25.12.2016, 13:30
    Place:
    Room 337-8 Taub Bld.

    CS will hold a symposium honoring Prof. Johann Makowsky’s retirement on: Logic in Computer Science and Combinatorics

    On the agenda greetings by CS Dean Prof. Irad Yavneh and talks by:
    Moshe Vardi
    Eldar Fischer
    Tomer Kotek
    Nadia Labai
    Elena Ravve
    Johann Makowsky

    More details and full program.

    The event will take place on Sunday, December 25 2016, between 13:00-17:00 at CS Taub 337, Technion.

    You are all invited!

  • Requirements for Tools for Hairy Requirements or Software Engineering Tasks

    Speaker:
    Daniel M. Berry - COLLOQUIUM LECTURE
    Date:
    Tuesday, 27.12.2016, 14:30
    Place:
    Room 337-8 Taub Bld.
    Link:
    http://www.cs.technion.ac.il/~colloq/20161227_14_30_Berry.html
  • On Artificial Olfaction, and How to Test For It

    Speaker:
    David Harel - COLLOQUIUM LECTURE
    Date:
    Tuesday, 3.1.2017, 14:30
    Place:
    Room 337-8 Taub Bld.
    Link:
    http://www.cs.technion.ac.il/~colloq/20170103_14_30_Harel.html
  • Antibiotic resistance: machine learning to the rescue

    Speaker:
    Roy Kishony - COLLOQUIUM LECTURE
    Date:
    Tuesday, 17.1.2017, 14:30
    Place:
    Room 337-8 Taub Bld.
    Link:
    http://www.cs.technion.ac.il/~colloq/20170117_14_30_Kishony.html