Colloq Seminar: New Algorithms for Ranking and Dimension Reduction

Nir Ailon (Google)

Tuesday, 30.12.2008, 14:30

Room 337-8 Taub Bld.

New Algorithms for Ranking and Dimension Reduction
The study of ranking crosses many disciplines.
Social choice theoreticians have been interested for centuries
in finding a good way to rank a set of candidates. Econometricians
have been asking for decades how people choose from (and more
generally rank) alternative sets. More recently, information retrieval
theoreticians and practitioners have been interested in ranking search
query results. In verification, practitione...

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Pixel Club Seminar: Not only size matters: regularized partial matching of shapes

Michael Bronstein (Novafora, Inc.)

Tuesday, 30.12.2008, 11:30

EE Meyer Building 1061

Partial matching is probably one of the most challenging problems in shape analysis.
The problem consists of matching similar parts of shapes that are dissimilar on the whole.
Conceptually, two shapes can be considered partially matching if they have significant similar parts,
with the simplest definition of significance being the size of the parts. Thus, partial matching can be
defined as a multcriterion optimization problem trying to simultaneously maximize the similarit...

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Theory Seminar: Derandomizing Algorithms on Product Distributions and Improved Implicit Probe Search using Same-source Extractors for very

Avinatan Hassidim (M.I.T.)

Sunday, 28.12.2008, 12:00

Taub 601

An important goal in algorithms and communication protocols is getting
the deterministic time complexity, respectively communication complexity,
closer to the best known randomized complexity. In this work, we investigate
the case where instead of one input, the algorithm \ protocol is given multiple
\emph{independent} samples from an \emph{arbitrary unknown} distribution.
We show that in this case a strong derandomization result can be obtained by a
simple argument. O...

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Simulation and Control of Quantum Systems

Ilan Degani

Thursday, 25.12.2008, 14:30

Room 337-8 Taub Bld.

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Bioinformatics Forum: Discovery of Mechanisms from Mathematical Modeling of DNA Microarray Data: Computational Prediction and Experimental Verification

Orly Alter (Biomedical Engineering, University of Texas at Austin)

Thursday, 25.12.2008, 13:30

Taub 601

DNA microarrays make it possible to record the complete molecular biological signals that guide the progression of cellular processes on genomic scales. I will describe the ability of mathematical models, that were created from these data using matrix and tensor computations, to predict previously unknown biological as well as physical principles, which govern the activities of DNA and RNA.
First, I will describe the use of singular value decomposition to uncover "asymmetric He...

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Theory Seminar: Hypergraph Ramsey Numbers

Benny Sudakov (UCLA)

Wednesday, 24.12.2008, 13:30

Amado 719

Abstract: The Ramsey number $r_k(s,n)$ is the minimum $N$ such that every
red-blue coloring of the $k$-tuples of an $N$-element set contains either
a red set of size $s$ or a blue set of size $n$, where a set is called red
(blue) if all $k$-tuples from this set are red (blue). The problem of
estimating Ramsey numbers is one of the central problems in modern
Combinatorics and it has received a considerable amount of attention in
the last 80 years.
In this talk we p...

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Pixel Club Seminar: Organizing Visual Data

Shai Avidan (Adobe Systems Inc.)

Wednesday, 24.12.2008, 11:30

EE Meyer Building 1061

The growth in the number of digital photographs calls for new and improved image editing tools to help users view, navigate and manipulate them. Many of these tasks can be reduced to instances of organizing visual data to satisfy user constraints. In this talk I will present three such tools that help organize visual data at the pixel, patch and image level: Seam Carving, The Patch Transform, and Infinite Images.
Seam Carving attempts to retarget an image to fit a specific displa...

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Pixel Club Seminar: Generalized Newton Method for Energy Formulations in Image Processing

Leah Bar (University of Minnesota, USA)

Tuesday, 23.12.2008, 11:30

EE Meyer Building 1061

Many problems in image processing are addressed via the minimization of a cost functional. The most prominent optimization technique is the gradient descent, often used due to its simplicity and applicability where other techniques, e.g., those coming from discrete optimization, can not be used. Yet, gradient descent suffers from a slow convergence, and often to just local minima which highly depends on the condition number of the functional Hessian. Newton-type methods, on the ot...

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Haifux, Linux Haifa Club: Breaking the ice with SELinux (part II)

Eli Billauer

Monday, 22.12.2008, 18:30

Taub 6

We will continue from "Policy syntax" this meeting (after a quick
review of the previous one).
We will also see how to write an SELinux module to keep a certain
application under control.
SELinux is an access permission system, which is running in many recent
distributions (with or without the computer owner's awareness).
Understanding how this system works seems to become a necessity for a
smooth administration of an updated Linux machine.
...

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CGGC Seminar: Generating surfaces and animation by refinement of curves and frames

Uri Itai (Mathematics, Technion)

Sunday, 21.12.2008, 12:40

Room 337-8 Taub Bld.

Subdivision schemes became popular in recent years in applications such
as computer graphics and CAGD (computer aided geometric design). Their
implementation is rather simple, yet there is a rich mathematical theory
behind them. We will introduce two basic subdivision schemes, (corner
cutting and the 4-point) and present implementation of them in computer
graphics and in animation....

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Colloq Seminar: Building on Conflicts: Computational Studies of Codes

Tali Kaufman (M.I.T.)

Thursday, 18.12.2008, 14:30

Room 337-8 Taub Bld.

Many interesting questions in coding theory revolve around conflicts
(tradeoffs). Among them are a conflict between structure and
randomness, and a conflict between density and symmetry. In some of
the cases the conflicts are helpful in understanding solutions for
questions (e.g. using the structure and randomness conflict we
obtain improved analysis of Reed Muller codes), while in other cases
these conflicts shed light on the inherent difficulty of the
questions.
In the...

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Bioinformatics Forum: MicroRNAs: from Targets to Function

Doron Betel (Memorial Sloan-Kettering Cancer Center, N.Y.)

Wednesday, 17.12.2008, 13:30

Taub 701

Small regulatory RNAs are a class of non-coding RNAs that are primarily involved in post-transcriptional
gene silencing. The principle members of this growing class are microRNAs and small interfering
RNAs (siRNAs) which guide a silencing complex to an mRNA target by base pairing at the 3 untranslated
region (3UTR).
In recent years, microRNAs have emerged as a major class of regulatory genes central to
a wide range of cellular activities, and their importance i...

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Small-size $eps$-Nets for Geometric Range Spaces.

Esther Ezra

Tuesday, 16.12.2008, 14:30

Room 337-8 Taub Bld.

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Gradient descent and fast artificial time integration

Uri Ascher

Sunday, 14.12.2008, 14:30

Room 337-8 Taub Bld.

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Theory Seminar: Approximation and calculation of low-degree polynomials

Shachar Lovett (Weizmann Institute of Science)

Sunday, 14.12.2008, 12:00

Taub 601

We consider private data analysis in the setting in which a trusted and trustworthy curator,
having obtained a large data set containing private information, releases to the public a
"sanitization'' of the data set that simultaneously protects the privacy of the individual
contributors of data and offers utility to the data analyst. We focus on the case where the
process is non-interactive; once the sanitization has been released the original data and the
curator play no...

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Pixel Club Seminar: Descriptor Based Methods in the Wild

Tal Hassner (CS, The Open University of Israel)

Tuesday, 09.12.2008, 11:30

EE Meyer Building 1061

Recent methods for learning the similarities between images have
presented impressive results on the problem of pair-matching
(same/not-same classification) of face images. In this talk we present
pair-matching results comparing the performance of image descriptor
based methods to the state of the art in same/not-same classification,
obtained on the Labeled Faces in the Wild (LFW) image set. We propose
various contributions, spanning several aspects of automatic ...

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Theory Seminar: Hardness amplification proofs require majority

Ronen Shaltiel (Haifa University)

Sunday, 07.12.2008, 12:00

Taub 601

A function $f$ is $\delta$-hard for some class of circuits if every
circuit in the class errs on a $\delta$-fraction of the inputs. For
various classes of constant depth small size circuits there are explicit
functions that are $\delta$-hard for ``small'' values of $\delta$.
For stronger circuit classes there are many ``hardness amplification
theorems'' that show how to transform any $\delta$-hard function $f$
into a ``harder'' function $g$ that is $(1/2-\epsilon)$-har...

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Parallel Repetition Theorem Reading Group: Parallel Repetition, Unique Games and Foams?

Prahladh Harsha (CS, University of Texas at Austin)

Wednesday, 03.12.2008, 12:00

Taub 201

In this reading group, we will study the parallel repetition theorem,
its connection to unique games and tiling in high dimensional spaces.
The parallel repetition theorem [Raz 1998] has been extremely useful
to compute the exact inapproximability of several optimization
problems. Two years ago, Holenstein gave a simplified proof of Raz's
theorem. Since then, there has been a flurry of activity in this area:
understanding the behavior for special type of 2-prover g...

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Portably preventing file race attacks with user-mode path resolution

Dan Tsafrir

Tuesday, 02.12.2008, 14:30

Room 337-8 Taub Bld.

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Theory Seminar: Partition Arguments in Multiparty Communication Complexity

Enav Weinreb (Computer Science, Technion)

Sunday, 30.11.2008, 12:00

Taub 601

Consider the ``plain'' multiparty communication complexity model,
where k players $P_1,\dots,P_k$ holding inputs
$x_1,\dots,x_k\in\bit^n$ (respectively) communicate in order to
compute the value $f(x_1,\dots,x_k)$. The main lower bound
technique for such communication problems is that of {\em
partition arguments}: partition the $k$-players into two disjoint
sets of players and find a lower bound for the induced two-party
communication complexity problem. In this paper, we s...

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Theory Seminar: Using classical topology in combinatorial problems

Eli Berger (Haifa University)

Wednesday, 26.11.2008, 13:30

Amado building 719

The idea of using topology in order to solve combinatorial problems has
been known for several decades, but only recently it started to become an
organized theory. In my talk I will introduce several classical
topological theorems such as Brouwer's fixed point theorem and Sperner's
Lemma and give the basic methods for using them in combinatorial settings.
I will also describe a new approach that may enable us to use the Borsuk
Ulam theorem in similar settings and hopefully o...

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The Netflix Prize: Quest for $1,000,000

Yehuda Koren

Tuesday, 25.11.2008, 14:30

Room 337-8 Taub Bld.

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Theory Seminar: Lower Bounds for Satisfiability and Related Problems

Dieter van Melkebeek (Univ. of Wisconsin)

Sunday, 23.11.2008, 12:00

Taub 601

Ever since the work of Cook and Levin, satisfiability has been
recognized as a central problem in computational complexity. It is
widely believed to be intractable, and yet till recently even a
linear-time logarithmic-space algorithm was not ruled out.
The last few years have seen considerable progress in time-space lower
bounds for satisfiability and closely related problems on various
models of computation. This talk will describe the state-of-the-art on
...

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Church's thesis proof

Yuri Gurevich

Wednesday, 19.11.2008, 14:30

Room 337-8 Taub Bld.

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Regular Specifications of Resource Requirements for Embedded Control Software

Gera Weiss

Tuesday, 11.11.2008, 14:30

Room 337-8 Taub Bld.

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Computer (and Human) Perfection at Checkers

Jonathan Schaeffer

Thursday, 06.11.2008, 14:30

Room 337-8 Taub Bld.

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Refactoring using Type Constraints (previously presented at SAS'07)

Frank Tip

Tuesday, 04.11.2008, 14:30

Room 337-8 Taub Bld.

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Pixel Club Seminar: Modeling Evolutionary Processes Using Quasispecies Theory

Emmanuel Tannenbaum (Ben Gurion University)

Tuesday, 04.11.2008, 11:30

Taub 4

This talk provides an introduction to quasispecies theory, a framework for modeling evolutionary dynamics that was originally introduced to study problems related to the origin of life. Since the original formulation of the theory by Manfred Eigen in 1971, quasispecies theory has been used to study evolutionary processes in a variety of other contexts, but with a focus on molecular and viral evolution. In recent years, we have worked to steadily develop quasispecies theory into a ...

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Cuts and Flows in Directed Graphs

Julia Chuzhoy RESCHEDULED

Tuesday, 07.10.2008, 14:30

Room 337-8 Taub Bld.

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Equilibria in Online Games

Roee Engelberg

Monday, 06.10.2008, 14:00

Taub 601

We initiate the study of scenarios that combine both online
decision making and interaction between non-cooperative agents. To
this end we introduce the notion of online games that model such
scenarios as non-cooperative games, and lay out the foundations
for studying this model. Roughly speaking, an online game captures
systems in which independent agents serve requests in a common
environment. The requests arrive in an online fashion and each is
designated to be served by a diff...

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Pixel Club Seminar: Compressed Sensing Meets Information Theory

Dror Baron

Thursday, 18.09.2008, 11:30

Room 337-8 Taub Bld.

Sensors, signal processing hardware, and algorithms are under
increasing pressure to accommodate ever larger data sets; ever faster
sampling and processing rates; ever lower power consumption; and
radically new sensing modalities. Fortunately, there have been
enormous increases in computational power. This progress has motivated
Compressed Sensing (CS), an emerging field based on the revelation
that a sparse signal can be reconstructed from a small number of
linear measurem...

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CGGC Seminar: Approximate Greatest Common Divisors and Polynomials Roots<br>
9:30-11:30, 13:00-15:00, Taub 337

Joab Winkler (CS, University of Sheffield)

Tuesday, 19.08.2008, 09:30

Room 337-8 Taub Bld.

The discussion of the structured condition number and Gauss' method for computing the roots of a
polynomial shows that a sequence of greatest common divisor (GCD) computations of two polynomials
must be performed. This is a classical problem in mathematics that is often solved by Euclid's algorithm.
This algorithm is satisfactory for symbolic computations with exact polynomials, but the computation
of the GCD of inexact polynomials is not trivial because it is ill-posed (not i...

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An Efficient Reduction of Ranking to Classification

Nir Ailon

Monday, 11.08.2008, 14:30

Room 601 Taub Bld.

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Query Understanding using Web Relevance Feedback

Andrei Broder

Sunday, 10.08.2008, 14:30

Room 337-8 Taub Bld.

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Pixel Club Seminar: SIPL Annual Projects Presentation

SIPL, Technion

Thursday, 07.08.2008, 13:30

EE Meyer Building 1003

See program and invitation
להלן הזמנה ותוכנית הכנס...

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CGGC Seminar: An Interface for Drawing and Searching Mathematical Figures

Yong-Jun Kim (Computer Science, Seoul National University)

Sunday, 03.08.2008, 12:40

Room 337-8 Taub Bld.

In this talk, I would like to present a user interface for drawing
mathematical figures which can be quite complex. The system is based on a
sketch interface especially designed for drawing mathematical figures. I
would also like to present a search interface that finds figures similar to
the one drawn by the user. Given a sketch by the user, the system searches
a database of pre-drawn figures, automatically finds similar figures, and
shows them in a certain sorted order...

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Theory Seminar: Pseudorandom graphs - what if distinguishers where first order

Asaf Nussbaum (Weizmann Institute of Science)

Sunday, 03.08.2008, 11:00

Room 337-8 Taub Bld.

We study the limits of efficient computation in the context of
constructing random-looking graph distributions that can be used to
emulate huge random graphs over N=2^n vertices. We suggest and analyze a
new criterion of faithful emulation, inspired by the famous 0/1-law of
random graphs. This 0/1-law states that any graph property T holds with
probability converging either to 0 or to 1, whenever T is expressible by
a single formula on graphs.
We consider preservi...

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Pixel Club Seminar: CT Denoising by K-SVD on the Cell processor

Dominik Bartuschat (CS, Erlangen University, Germany)

Wednesday, 30.07.2008, 00:00

Taub 601

The K-SVD algorithm is a powerful tool for image denoising but
computationally quite intensive. In order to accelerate it we
implement the most time consuming parts like sparse coding and
assembling the final denoised image vectorized and in parallel on the
Cell processor. The Cell processor is a heterogeneous multicore system
consisting of a general purpose Power-PC processor unit (PPU) and
several fast co-processors, the synergistic processor elements (SPEs).
We present r...

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Bioinformatics Forum: Whole Population, Genomewide Mapping of Hidden Relatedness

Sasha Gusev (Columbia University)

Thursday, 24.07.2008, 13:30

Taub 601

Identifying and quantifying the sharing of genetic material between individuals within a population is
an important step in accurately using genealogical relationships for disease analysis as well as improving
our understanding of demography. However, exhaustive pairwise analysis which has been successful in
small cohorts cannot keep up with the current torrent of genotype data. We present GERMLINE, a robust
algorithm for identifying pairwise segmental shar...

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Math-Club Seminar: Probabilistic Reasoning

Professor Noga Alon (Tel Aviv University, 2008 Israel Prize recipient)

Wednesday, 23.07.2008, 16:30

Computer Science Taub 1

Abstract: The discovery that deterministic statements can be proved by
probabilistic reasoning, led already more than fifty years ago to several
striking results in various mathematical disciplines. It soon became clear
that the method, which is now called the probabilistic method, is a very
powerful tool for proving results in Discrete Mathematics.
After some light examples that illustrate the fact that probabilistic
arguments may be counter-intuitive, I will sketch...

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An optimal coin toss protocol

Professor Moni Naor

Monday, 21.07.2008, 14:30

Room 337-8 Taub Bld.

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Real Time Java

Sun Microsystems lecture

Sunday, 20.07.2008, 14:30

Room 337-8 Taub Bld.

The lecture topics are:
1) Real Time programming in a nutshell.
2) Programming languages comparison (Real Time related).
3) Java vs. C/C++ with relevant benchmarks.
4) Why Java, Why Java for Real Time?
5) What is the Real Time Java Standard?
6) Sun Real Time Java technology
7) Customers and case studies
6) Real Time Java competitive landscape
For more information please contact David: David.Roitman at Sun.com
...

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Theory Seminar: Two Query PCP with Sub-Constant Error

Dana Moshkovitz, Weizmann

Sunday, 20.07.2008, 11:00

Taub 337

We show that the NP-Complete language 3Sat has a PCP
verifier that makes two queries to a proof of almost-linear size
and achieves sub-constant probability of error o(1). The
verifier performs only projection tests, meaning that the answer
to the first query determines at most one accepting answer to the
second query.
Previously, by the parallel repetition theorem, there were PCP
Theorems with two-query projection tests, but only (arbitrarily
small) constant erro...

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An Efficient Reduction of Ranking to Classification

Nir Ailon (POSTPONED FROM 3/7/08)

Thursday, 17.07.2008, 14:30

Room 337-8 Taub Bld.

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The finite harmonic oscillator with applications to radar and communication

Ronny Hadani

Tuesday, 15.07.2008, 14:30

Room 337-8 Taub Bld.

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Theory Seminar: The Constant-Depth Complexity of k-Clique

Benjamin Rossman (M.I.T.)

Sunday, 13.07.2008, 11:00

Room 337-8 Taub Bld.

will discuss a recent lower bound of Omega(n^(k/4)) on the size of depth-d
circuits for the k-clique problem on n-node graphs. This improves previous
lower bounds (e.g. Omega(n^(k/89d2)) [P. Beame '90]) by removing dependence
on d from the exponent of n. This result has an interesting corollary in
logic: it implies that the "bounded variable logics" FO1, FO2, ..., FO^k,
... (where FO^k consists of first-order sentences in which no subformula has
no more than k free variab...

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Bioinformatics Forum: Systems Macro-Biology: Less is More in Disease Biomarkers

Prof. Simon Kasif (Boston University and Children's Hospital, Boston)

Thursday, 10.07.2008, 13:30

Taub 601

We describe several new methodologies for developing and evaluating novel diagnostics for diabetes and cancer. In the first part of the talk we describe the Gene Network Enrichment Analysis (GNEA) methodology for identifying molecular markers for diabetes. This approach suggests that network based techniques might be more sensitive and accurate at identifying disease progression than single genes. At the same time we should pay significant attention to both the biological inter...

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Pixel Club Seminar: Active learning in dynamical systems – from robotics to computational biology

Prof. Hod Lipson (Mechanical & Aerospace Engineering, Computing & Information Science,
Cornell University)

Thursday, 10.07.2008, 11:30

Room 337-8 Taub Bld.

This talk will describe new active learning processes for automated modeling of dynamical systems across a number of disciplines. One of the long-standing challenges in robotics is achieving robust and adaptive performance under uncertainty. One approach to adaptive behavior is based on self-modeling, where a system continuously evolves multiple simulators of itself in order to make useful predictions. The robot is rewarded for actions that cause disagreement among predictions of ...

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CGGC Seminar: Smooth Surface Fitting (Tutorial)

Stefanie Hahmann (INPG, Grenoble)

Monday, 07.07.2008, 10:00

Room 337-8 Taub Bld.

The recent ability to measure quickly and inexpensively dense
sets of points on physical objects has deeply influenced the
way engineers represent shapes in CAD systems, animation
software or in the game industry. Many researchers advocated
to completely bypass smooth surface representations, and to
stick to a dense mesh model throughout the design process. Yet
smooth analytic representations are still required in standard
CAD systems and animation software, for reas...

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Theory Seminar: Combinatorial Construction of Locally Testable Codes

Or Meir, (Weizmann Institute of Science)

Sunday, 06.07.2008, 11:00

Room 337-8 Taub Bld.

An error correcting code is said to be locally testable if there is a
test that
can check whether a given string is a codeword of the code, or rather
far from
the code, by reading only a constant number of symbols of the string.
Locally
Testable Codes (LTCs) were first explicitly studied by Goldreich and
Sudan (J. ACM 53(4)) and
since then several constructions of LTCs were suggested.
While the best known construction of LTCs achieves very efficient
parameter...

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On the Hardness of Being Truthful

Michael Schapira

Thursday, 03.07.2008, 14:30

Room 337-8 Taub Bld.

The central problem in computational mechanism design is the tension
between incentive compatibility and computational efficiency. We address
this question in the context of a novel mechanism design problem which we
call the combinatorial public project problem. We show that, even though
this problem is easily solvable from a computational viewpoint, and from
an economic perspective, no algorithm which is simultaneously truthful
and runs in polynomial-time can obtain any...

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Pixel Club Seminar: "Cognitive" Memory and its Applications

Prof. Bernard Widrow (EE, Stanford University)

Wednesday, 02.07.2008, 11:30

Room 337-8 Taub Bld.

Regarding the workings of the human mind, memory and pattern recognition seem to be intertwined.
You generally do not have one without the other. Taking inspiration from life experience, a new
form of computer memory has been devised. Certain conjectures about human memory are keys to the central idea.
The design of a practical and useful "cognitive" memory system is contemplated, a memory system that
may also serve as a model for many aspects of human memory. The new memory...

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Property Testing and Combinatorial Approximation

Arie Matsliah

Wednesday, 25.06.2008, 16:00

Taub 601

With the recent advances in technology, we are faced with the need to process increasingly larger amounts of data
increasingly faster.
Originally, a problem was considered computable if there was an algorithm that could decide it in finite time given any
input instance. Later came the notion of polynomial time computation, and then the possibility of making computations
faster through use of parallel machines. However, the algorithms involved still face the obvious obstacle of...

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List error-correction: New constructions, algorithms, and applications

Venkatesan Guruswami

Tuesday, 24.06.2008, 14:30

Room 337-8 Taub Bld.

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Pixel Club Seminar: Fenchel Duality with Applications to Inference

Amnon Shashua (School of Engineering and Computer Science, Hebrew University of Jerusalem)

Tuesday, 24.06.2008, 14:00

Room 337-8 Taub Bld.

Quite a number of problems involving inference from data, whether visual data or otherwise, fall into the category of optimization. I will describe a general scheme for sequential and parallel (message passing) update rules based on the framework of Fenchel duality. The presentation will be done in the context of two applications (i) distributed
(parallel) Support-Vector-Machines (SVM) for handling large scale problems (to be presented at CVPR'08), (ii) Graphical Model inference...

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Pixel Club Seminar: Theoretical Results on Robot Localization, Mapping and Goal-Directed Navigation in Unknown Terrain

Sven Koenig (University of Southern California)

Tuesday, 24.06.2008, 11:30

Room 337-8 Taub Bld.

Path planning for robots in unknown terrain has been studied in both theoretical robotics and theoretical computer science. However, empirical robotics researchers have often developed their own planning methods. These planning methods have been demonstrated on mobile robots that solve complex real-world tasks and perform well in practice. I will discuss some of these planning methods (namely, Planning with the Freespace Assumption, Greedy Mapping and Greedy Localization) and show...

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Pixel Club Seminar: Simple, Fast Simulation and Artistic Control of Cloth and Thin Shells

Eitan Grinspun (Computer Science, Columbia University)

Sunday, 22.06.2008, 14:00

EE Meyer Building 1061

What does it take to build fast simulators for cloth and thin
shells—in particular to do so with code that is simple to implement,
debug, and maintain? Our group's belief is that simple geometric
observations help to address all these goals. I will survey my
students' recent work on the discrete differential geometry of thin,
flexible surfaces, and focus on a couple simple geometric observations
that lead to efficient and simple models for bending, stretching, and
artisti...

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Theory Seminar: Quantum Multi Prover Interactive Proofs with Communicating Provers

Avinatan Hassidim, (Hebrew University of Jerusalem)

Sunday, 22.06.2008, 11:00

Room 337-8 Taub Bld.

We introduce a variant of Quantum Multi Prover Interactive Proofs (QMIP),
where the provers do not share entanglement, the communication
between the verifier and the provers is quantum, but the provers
are unlimited in the classical communication between them.
At first, this model may seem very weak, as provers who exchange
information seem to be equivalent in power to a simple prover.
This in fact is not the case - we show that any language in NEXP
can be recognized in thi...

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Beyond Bandlimited Sampling: Nonideal Sampling, Smoothness and Sparsity

Yonina Eldar

Tuesday, 17.06.2008, 14:30

Room 337-8 Taub Bld.

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Pixel Club Seminar: Sampling Sampling

Alan Oppenheim (Massachusetts Institute of Technology)

Sunday, 15.06.2008, 16:00

EE Meyer Building 1003

Digital processing of analog signals naturally requires a
representation of continuous time signals as a discrete-time
sequence. The most common representation of this type is based on
the Shannon-Nyquist sampling theorem which provides an exact
representation for band limited signals sampled at a sufficiently
high rate but leads to aliasing error when the signal is under
sampled. In this talk a number of other approaches are discussed
to obtai...

[ Full version ]

[ Full version ]

Bioinformatics Forum: Alternative Splicing Events of Arbitrary Dimension in Splicing Graphs

Micha Sammeth (Genomic Regulation, Barcelona, Spain)

Sunday, 15.06.2008, 13:30

Taub 701

Eukaryotic splicing structures are known to involve a high degree of alternative forms derived from a premature transcript by alternative splicing (AS). With the advent of new sequencing technologies, evidence for new splice forms becomes more and more easily availablebit by bit revealing that the true splicing diversity of "AS events often comprises more than two alternatives and therefore cannot be sufficiently described by pairwise comparisons as conducted in analyzes hitherto....

[ Full version ]

[ Full version ]

Theory Seminar: Expander codes, Euclidean Sections, and Compressed Sensing

Venkatesan Guruswami, (Washington University)

Sunday, 15.06.2008, 13:30

Room 337-8 Taub Bld.

Classical results in high-dimensional geometry from the 1970's state that a random subspace of R^N of dimension N/2 has "distortion" O(1) w.h.p where the distortion is measured by sqrt{N} times the largest ratio of the L_2 to L_1 norms of a vector in the subspace. (So each vector in the subspace has its mass spread nearly evenly over a constant fraction of the coordinates.) This result is a particular example of the use of the probabilistic method, a technique which is ubiquitous ...

[ Full version ]

[ Full version ]

CGGC Seminar: Formulae and Growth Rates of High-Dimensional Polycubes

Gill Barequet (CS, Technion)

Sunday, 15.06.2008, 13:00

Room 337-8 Taub Bld.

...

[ Full version ]

[ Full version ]

An Algebraic Approach to Rule-Based Information Extraction

Frederick R. Reiss

Thursday, 12.06.2008, 14:30

Room 337-8 Taub Bld.

...

[ Full version ]

[ Full version ]

Math-Club Seminar: On the Security of GSM Cellular Phones

Eli Biham (Computer Science, Technion)

Wednesday, 11.06.2008, 16:30

Taub 1

Abstarct:In this talk we describe the ciphers and protocols used for
the GSM cellular phone network, and discuss the (in)security of the
system. We describe several techniques to attack the ciphers A5/2 and
A5/1, and how they can be applied as a ciphertext-only attack. We also
show that active attacks on the protocols can recover keys of ciphers that
are not used during that transmission. As a result, it is possible to
listen in to GSM phone conversations, steal calls during...

[ Full version ]

[ Full version ]

Approximate median selection

Micha Hofri (NEW DATE instead 5/6)

Wednesday, 11.06.2008, 11:30

Room 337-8 Taub Bld.

...

[ Full version ]

[ Full version ]

Pixel Club Seminar: 3D Objects Description and Classification by Implicit Polynomials

Hilla Ben-Yaacov (EE, Technion)

Tuesday, 10.06.2008, 11:30

EE Meyer Building 1061

3D Objects Description and Classification by Implicit Polynomials
...

[ Full version ]

[ Full version ]

Theory Seminar: The finite field Kakeya conjecture

Zeev Dvir (Weizmann Institute)

Sunday, 08.06.2008, 11:30

Room 337-8 Taub Bld.

A Kakeya set in F^n, where F is a finite field, is a set containing a line in every direction. The finite field Kakeya conjecture states that the size of such sets is bounded from below by C_n*|F|^n, where C_n depends only on the dimension n. I will talk about the recent proof of this conjecture and its connection to problems in theoretical computer science....

[ Full version ]

[ Full version ]

Approximate median selection

Micha Hofri

Thursday, 05.06.2008, 14:30

Room 337-8 Taub Bld.

...

[ Full version ]

[ Full version ]

Maximum Degree-Bounded Connected Subgraph: Hardness and Approximation

Ignasi sau

Wednesday, 04.06.2008, 15:30

Room 337-8 Taub Bld.

...

[ Full version ]

[ Full version ]

On the Nature of Progress

Nir Shavit

Tuesday, 03.06.2008, 14:30

Room 337-8 Taub Bld.

...

[ Full version ]

[ Full version ]

Agnostically Learning Decision Trees

Adam Kalai

Sunday, 01.06.2008, 14:30

Room 337-8 Taub Bld.

...

[ Full version ]

[ Full version ]

TBA

Oded Goldreich - in memory of Shimon Even

Wednesday, 28.05.2008, 16:30

Room 337-8 Taub Bld.

...

[ Full version ]

[ Full version ]

Lower Bounds in the Noisy Networks using Sampling Algorithms

Jaikumar Radhakrishnan

Tuesday, 27.05.2008, 14:30

Room 337-8 Taub Bld.

...

[ Full version ]

[ Full version ]

John Smolin (IBM Watson at Yorktown Hights, NY)

Tuesday, 20.05.2008, 14:30

Taub 6

The black hole information loss paradox has plagued scientists since
Hawking's discovery that black holes evaporate thermally in contradiction to
the unitarity expected by quantum mechanics. I will explain just what the
problem is, and show that one of the central presumptions of the debate is
incorrect.
It had been thought that (obviously) either all the information must remain in
the black hole until it has completely evaportate OR it must leak out earlier.
Howeve...

[ Full version ]

[ Full version ]

Logic in Access Control

Yuri Gurevich

Sunday, 18.05.2008, 14:30

Room 337-8 Taub Bld.

...

[ Full version ]

[ Full version ]

Formulae and growth rates of high-dimensional polycubes

CGGC Seminar: Gill Barequet (Computer Science, Technion)

Sunday, 18.05.2008, 14:00

Room 337-8 Taub Bld.

A $d$-dimensional polycube is a connected set of $d$-dimensional cubes on an
orthogonal lattice, where connectivity is through $(d-1)$-dimensional faces.
A polycube is said to be proper in $d$ dimensions if it spans all the $d$
dimensions, that is, the convex hull of the centers of all its cubes is
$d$-dimensional.
We prove a few new formulae for the numbers of (proper and total) polycubes,
and show that (2d-3)e + O(1/d) is the asymptotic growth rate of the number
o...

[ Full version ]

[ Full version ]

Abstraction-Refinement and Modularity in mu-Calculus Model Checking

Sharon Shoham Buchbinder

Wednesday, 14.05.2008, 16:00

Taub 601

Model checking is an automated technique for checking
whether or not a given system model fulfills a desired property,
described as a temporal logic formula. Yet, as real models tend to
be very big, model checking encounters the state-explosion problem,
which refers to its high space requirements. Two of the most
successful approaches to fighting the state-explosion problem in
model checking are abstraction and compositional model checking.
Abstractions hide certain detai...

[ Full version ]

[ Full version ]

Natural history and evolutionary principles of gene duplication in fungi

Nir Friedman

Tuesday, 13.05.2008, 14:30

Room 337-8 Taub Bld.

...

[ Full version ]

[ Full version ]

CGGC Seminar: Interactive Rendering of Dynamic Geometry

Kai Hormann (Clausthal Institute of Technology)

Tuesday, 13.05.2008, 11:00

Taub 601

Fluid simulations typically produce complex three-dimensional
iso-surfaces whose geometry and topology change over time.
The standard way of representing such dynamic geometry is by a
set of iso-surfaces that are extracted individually at certain
time steps. An alternative strategy is to represent the whole
sequence as a four-dimensional tetrahedral mesh. The iso-surface
at a specific time step can then be computed by intersecting the
tetrahedral mesh with a three-dimens...

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[ Full version ]

Counting polycubes without the dimensionality curse

CGGC Seminar: Gadi Aleksandrowicz (Computer Science, Technion)

Sunday, 11.05.2008, 13:00

Room 337-8 Taub Bld.

$d$-dimensional polycubes are the generalization of planar polyominoes
to higher dimensions. That is, a $d$-D polycube of size $n$ is a connected
set of $n$ cells (hypercubes) of an orthogonal $d$-dimensional lattice,
where connectivity is through $(d-1)$-dimensional faces of the cells.
Computing $A_d(n)$, the number of distinct $d$-dimensional polycubes of
size $n$, is a long-standing elusive problem in discrete geometry.
In a previous work we described the generalization ...

[ Full version ]

[ Full version ]

Pixel Club Seminar: Fast acquisition and reconstruction in imaging enabled by sampling theory

Yoram Bresler (University of Illinois at Urbana-Champaign)

Tuesday, 06.05.2008, 11:30

Taub 701

We survey applications of classical and of time-sequential sampling
theory and some of its recent extensions, respectively, in two
complementary areas. First to reduce the computation for tomographic
reconstruction from $O(N^3)$
to $O(N^2\log N)$ for an $N \times N$ image, with similar acceleration
for 3D images. And second, to reduce acquisition requirements for
dynamic imaging below those predicted by classical theory.
In both areas, the savings demonstrated in practic...

[ Full version ]

[ Full version ]

Theory Seminar: Developments in the Area of Communication Complexity

Adi Shraibman (Math & CS, Weizmann Inst.)

Tuesday, 06.05.2008, 10:30

Taub 401

We will describe the results from a series of papers, starting from papers of Forster, Ben-David and others to more recent works of Sherstov
and Chattopadhyay. The topics of these papers are learning, communication and computational complexity. Examples of some contributions of these papers are
1. The first lower bound on unbounded error probabilistic communication complexity.
2. Definition and study of learning theoretic quantities such as margin complexity...

[ Full version ]

[ Full version ]

Designing Competitive Online Algorithms via a Primal-Dual Approach

Niv Buchbinder

Wednesday, 16.04.2008, 16:30

Taub 601

In this work we study a wide range of online covering and
packing problems with various objectives. We provide a unified approach,
based on a clean primal-dual method, for the design and analysis of online
algorithms for this large class of problems. In particular, our
analysis uses weak duality rather than a tailor made (i.e., problem
specific) potential function. We show how to apply the primal-dual
approach to many interesting problems. Examples consist of the ski
rental prob...

[ Full version ]

[ Full version ]

Pixel Club Seminar: The Importance of Being Earnest...about Optimality

Alfred M.Bruckstein (Computer Science, Technion)

Sunday, 13.04.2008, 14:30

EE Meyer Building 1061

I shall discuss the many ways one can do optimal image or
signal denoising, and the difficulties in selecting between
the various optimal solutions.
...

[ Full version ]

[ Full version ]

A Geometric Approach to Detecting Global Properties over Distributed Data

Izchak Tzachi Sharfman

Wednesday, 09.04.2008, 16:30

Taub 601

A basic construct in many distributed systems is the detection of global properties over distributed data. Examples include a wireless sensor network, where we would like to receive an alert every time the average of the temperature readings taken by the sensors exceeds a given threshold, or a distributed search engine, where we would like to determine the set of search terms whose frequency of use exceeds a given threshold.
Until recently, research has focus on detecting gl...

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[ Full version ]

Recent advances in online convex optimization

Elad Hazan

Tuesday, 08.04.2008, 14:30

Room 337-8 Taub Bld.

...

[ Full version ]

[ Full version ]

Pixel Club Seminar: Fast Block Motion Estimation Using Gray‐Code Kernels

Yair Moshe (Computer Science, Haifa Univ.)

Tuesday, 08.04.2008, 11:30

2008-04-01 14:30:00

Motion estimation plays an important role in modern video coders. In such coders, motion is estimated using a block matching algorithm that estimates the amount of motion on a block‐by‐block basis. A full search technique for finding the best matching blocks delivers good accuracy but is usually not practical because of its high computational complexity. In this talk, a novel fast block‐based motion estimation algorithm is presented. This algorithm uses an efficient projecti...

[ Full version ]

[ Full version ]

Painting Rectilinear Pictures Without Picasso

Howard Karloff

Sunday, 06.04.2008, 14:30

Room 337-8 Taub Bld.

...

[ Full version ]

[ Full version ]

Theory Seminar: A combinatorial construction of almost-Ramanujan graphs using the
zig-zag product

Avraham Ben-Aroya (Tel-Aviv Univ.)

Sunday, 06.04.2008, 11:00

Room 337-8 Taub Bld.

Reingold, Vadhan and Wigderson [FOCS'00] introduced the graph zig-zag
product. This product combines a large graph and a small graph into one
graph, such that the resulting graph inherits its size from the large graph,
its degree from the small graph and its spectral gap from both. Using this
product they gave the first fully-explicit combinatorial construction of
expander graphs. They showed how to construct $D$-regular graphs having
spectral gap $1-O(D^{-\frac{1}{3}})$. In...

[ Full version ]

[ Full version ]

Windows Core Architecture: compare and contrast

Dave Probert

Thursday, 03.04.2008, 14:30

Taub 2

...

[ Full version ]

[ Full version ]

On the complexity of graph polynomials

Markus Blaeser

Tuesday, 01.04.2008, 14:30

Room 337-8 Taub Bld.

...

[ Full version ]

[ Full version ]

Geometric deformations

Yaron Lipman (Computer Science, Tel Aviv Univ.)

Sunday, 30.03.2008, 13:00

Room 337-8 Taub Bld.

CGGC Seminar: Deforming objects in a "shape preserving" manner is a challenging problem
with various applications in geometric modeling and computer graphics. In
this talk I will examine two geometric-driven approaches to the problem.
First, reformulating the problem using the notion of Cartan's moving frames
reveals an intriguing relationship between harmonic maps into the group of
rotations and shape preserving deformations. The moving frames are known in
di...

[ Full version ]

[ Full version ]

Theory Seminar: Secure Internet Path Quality Monitoring: Tradeoffs in Security and Efficiency

David Xiao (Princeton)

Sunday, 30.03.2008, 11:00

Room 337-8 Taub Bld.

The basic foundations of the Internet are surprisingly vulnerable to simple attacks that could be mounted
by rogue hackers or result from simple misconfiguration. One area that remains particularly exposed to
attacks is routing: packets usually traverse many intermediate routers on their way from a source to their
destination. Since these routers may belong to other (possibly malicious) organizations, how do we
guarantee that our packets arrive as intended at their desti...

[ Full version ]

[ Full version ]

Towards Universal Semantic Communication

Madhu Sudan

Tuesday, 25.03.2008, 14:30

Room 337-8 Taub Bld.

...

[ Full version ]

[ Full version ]

Computational Awareness

Lance Fortnow

Thursday, 20.03.2008, 14:30

Room 337-8 Taub Bld.

...

[ Full version ]

[ Full version ]

Pixel Club Seminar: Aspects of invariant shape processing

Alexander Brook (Computer Science, Technion)

Monday, 17.03.2008, 10:30

Taub 601

The lecture deals with invariance in image processing, with emphasis on
invariance of shapes and curves. There are two main topics. First, we
consider scale invariance, review existing scale invariant measures and
discuss the different ways in which an algorithm can be scale invariant.
We then point out some dangers inherent in fully scale invariant
algorithms. Second, we present an equi-affine invariant shape matching
mathod, which is also invariant to resampling, robust to...

[ Full version ]

[ Full version ]

Datacenter of the future

Tilak Agerwala

Thursday, 13.03.2008, 11:00

Room 337-8 Taub Bld.

...

[ Full version ]

[ Full version ]

The Cloning Method for Combinatorial Optimization, Countingand Rare Events Using Gibbs Sampler

Reuven Rubinstein and Andrey Dolgin

Tuesday, 11.03.2008, 14:30

Room 337-8 Taub Bld.

...

[ Full version ]

[ Full version ]

Object and Reference Immutability using Java Generics

Yoav Zibin

Tuesday, 04.03.2008, 14:30

Room 337-8 Taub Bld.

...

[ Full version ]

[ Full version ]

Theory Seminar: Lower Bounds for Edit Distance Estimation

Robert Krauthgamer (Weizmann Institute and IBM Almaden)

Sunday, 02.03.2008, 16:30

Room 337-8 Taub Bld.

The edit distance between two strings is defined as the number of
insertions/deletions/substitutions needed to transform one string into
the other. This distance plays a key role in several fields like
computational biology and text processing.
Edit distance appears to be notoriously difficult to deal with
algorithmically (both theoretically and in practice). However, no
nontrivial computational lower bounds for it are known, and the only
negative evidence known i...

[ Full version ]

[ Full version ]

Moadon Matemati: The longest proof

Prof. David Chillag (Mathematics, Technion)

Wednesday, 27.02.2008, 16:30

Taub 1

The mathematical theorem having the longest
proof is the classification of the finite simple
groups. In this talk we will try to understand the
statement of the theorem and its importance.
The lecture will be in Hebrew.
ההרצאה תינתן בעברית....

[ Full version ]

[ Full version ]

Pixel Club Seminar: Multi-sensor human action analysis

Cristian Canton-Ferrer (Image and Video Processing Group
UPC, Barcelona Spain)

Tuesday, 26.02.2008, 11:00

EE Meyer Building 815

Multi-camera environments allow exploiting spatial redundancy that might be
used by analysis algorithms to produce more robust results. These algorithms
may be applied for a variety of tasks ranging from human 3D scene volume
reconstruction, human motion capture, gesture analysis or focus of attention
tracking. Combining this multi-camera information with audio information
would allow defining multimodal data analysis systems. This talk will
present two research lines within...

[ Full version ]

[ Full version ]

Theory Seminar: Hardness-Randomness Tradeoffs for Bounded Depth Arithmetic Circuits

Zeev Dvir (Weizmann Institute of Science)

Sunday, 24.02.2008, 11:00

Room 337-8 Taub Bld.

We show that lower bounds for bounded depth arithmetic circuits imply
derandomization of polynomial identity testing for bounded depth
arithmetic circuits. More formally, if there exists an explicit
polynomial f(x_1,...,x_m) that cannot be computed by a depth d
arithmetic circuit of small size then there exists an efficient
deterministic algorithm to test whether a given depth d-8 circuit is
identically zero or not (assuming the individual degrees of the tested
circuit are ...

[ Full version ]

[ Full version ]

Static Specification Mining Using Automata-Based Abstractions

Eran Yahav

Tuesday, 19.02.2008, 14:30

Room 337-8 Taub Bld.

...

[ Full version ]

[ Full version ]

Pixel Club Seminar: On Isometry, Self-Symmetry, and Biometry

Ron Kimmel

Sunday, 17.02.2008, 14:30

EE Meyer Building 1061

Our world is filled with nonrigid objects that can deform and
bend. Nonrigid shapes appear at all scales - from our body, its
organs and tissues, to tiny bacteria and microscopic protein
molecules. When trying to analyze nonrigid shapes the richness of
the possible deformations poses a challenge due to the large
number of degrees of freedom. Thus, generally speaking, explicit
analysis of nonrigid objects has so far been avoided. Today, there
is a co...

[ Full version ]

[ Full version ]

Pixel Club Seminar: On texture and image interpolation using Markov models

Shira Nemirovsky, EE, Technion

Tuesday, 12.02.2008, 11:30

EE Meyer Building 1061

Random field models characterize the correlation among neighboring pixels in an image. Specifically, a wide-sense Markov model is obtained by assuming a separable correlation function for a 2D auto-regressive (AR) model. This model is applicable to image restoration, image compression, and texture classification and segmentation. In this work we explore the effect of sampling on statistical features of an image such as histogram and the autocorrelation function. We show that the M...

[ Full version ]

[ Full version ]

CGGC Seminar: SolidWorks as geometry engine for engineers

Udi Bahat (Systematics Ltd.)

Sunday, 10.02.2008, 13:00

Room 337-8 Taub Bld.

"The Challenge", Definitions, GUI, basic and smart geometry in 2D and 3D,
basic model, "styled" model, shape manipulations, hybrid design, develop
challenge.
...

[ Full version ]

[ Full version ]

Theory Seminar: Local testing of direct products

Irit Dinur (Weizmann Institute of Science)

Sunday, 10.02.2008, 11:00

Room 337-8 Taub Bld.

Given a function f:[n]-->{0,1}, its k-wise direct product encoding
is the function F:[n]^k --> {0,1}^k defined by
F(x_1,..x_k) = (f(x_1),...,f(x_k))
This simple "encoding" is useful in PCP-like settings, when we want to
simulate reading k arbitrary values of f by accessing only a constant
number of inputs of the encoding F.
The main challenge is to test that a given F is indeed a "correct"
encoding of some f by reading only few (ultimately 2) random values in
F. This is ca...

[ Full version ]

[ Full version ]

On the complexity of infinite computations

Damian Niwinski

Thursday, 07.02.2008, 14:30

Room 337-8 Taub Bld.

...

[ Full version ]

[ Full version ]

Using coupling between residues based on evolutionary data for protein structure analysis

Eran Eyal (CB, School of Medicine, University of Pittsburgh)

Thursday, 07.02.2008, 13:30

Taub 601

Multiple sequence alignments possess important information, not only about functionally and structurally important conserved regions, but also about coupling between residues. Recently we have developed a unique method to detect such coupling based on substitution matrices of residue pairs. I will describe the method and show how it performs at structural analysis tasks as contact prediction and discrimination of decoy sets. I will then show recent results that demonstrate how cor...

[ Full version ]

[ Full version ]

Theory Seminar: The Power of VCG: On Algorithms that are Maximal In Range

Shahar Dobzinski (CS @ Engineering, Huji)

Sunday, 03.02.2008, 11:00

Room 337-8 Taub Bld.

Consider the following simple type of approximation algorithms: limit the set of possible outcomes, and completely optimize over the restricted subrange. In this talk we will study the power of this type of algorithms in two settings: multi-unit auctions, and combinatorial auctions with subadditive bidders.
From a game-theoretic point of view, our results provide a characterization of the power of the main positive result of mechanism design the VCG mechanism. Another ...

[ Full version ]

[ Full version ]

CGGC Seminar: Coupling surface and tetrahedral mesh generation with the restricted Delaunay triangulation

Pierre Alliez (CS, INRIA Sophia Antipolis)

Wednesday, 30.01.2008, 15:00

Room 337-8 Taub Bld.

A Delaunay triangulation restricted to a surface is obtained by
filtering a 3D Delaunay triangulation. Filtering herein consists of
selecting a subset of the 3D Delaunay facets whose dual edges intersect
the surface. In this talk I will explain how the restricted Delaunay
triangulation paradigm can be used to simultaneously mesh a surface
together with its interior. I will then describe two mesh generation
algorithms along these lines and show a demo made with components fro...

[ Full version ]

[ Full version ]

Generating Programs from Specifications (with some observations on the modularity of object oriented systems)

David Feitelson

Tuesday, 29.01.2008, 14:30

Room 337-8 Taub Bld.

...

[ Full version ]

[ Full version ]

Pixel Club Seminar: Image Processing using Diffusion with Schrödinger's Potential

Ori Honigman (EE, Technion)

Tuesday, 29.01.2008, 11:30

EE Meyer Building 1061

The complex diffusion process, recently introduced in image processing and computer vision by combining the linear diffusion equation and the 'free-particle' Schrödinger equation, is further generalized by incorporating the Schrödinger potential. We incorporate the potential into the complex diffusion equation, introducing some kind of 'dynamic boundary conditions' that serve as a filtering or even enhancing mechanism for textures. The Schrödinger potential is self-adopting to ...

[ Full version ]

[ Full version ]

Jeremy-Yrmeyahu Kaminski, Dept. of Mathematics, Holon Inst. of Technology

Monday, 28.01.2008, 10:30

Taub 401

1. Basic concepts in algebraic geometry (affine and projective varieties, morphisms, dimension, degree)
2. Computational tools: Groebner basis, resultants
3. Basic applications including solving polynomial systems
4. Some more involved constructions like Grassmannians and Chow forms.
...

[ Full version ]

[ Full version ]

CGGC Seminar: A decade of CGAL arrangements and applications

Dan Halperin, Dept. of Computer Science, Tel Aviv University

Sunday, 27.01.2008, 13:00

Taub 337

The Computational Geometry Algorithms Library, CGAL,
is the largest software collection of algorithms and data
structures in Computational Geometry available today.
It started a little over a decade ago as a European research
project with a small number of partners and has grown
over the years to be a huge open source project. The
arrangement package of CGAL, developed at Tel Aviv
University, constructs, maintains, traverses, and answers
queries on two-dimensional arrangem...

[ Full version ]

[ Full version ]

Theory Seminar: Trapdoors for Hard Lattices, and New Lattice-based Cryptography

Vinod Vaikuntanathan, MIT

Sunday, 27.01.2008, 11:00

Room 337-8 Taub Bld.

We show that disjointness requires randomized communication
Omega(n^{1/2k} / (k-1)2^{k-1}2^{2^{k-1}}) in the general k-party
number-on-the-forehead model of complexity. The previous
best lower bound was Omega (\log n / k-1). By results of Beame, Pitassi, and
Segerlind, this implies 2^{n^{Omega(1)}} lower bounds on the size of tree-like Lovasz-Schrijver proof
systems needed to refute certain unsatisfiable CNFs, and super-polynomial lower bounds on the
size of any tree-lik...

[ Full version ]

[ Full version ]

Theory Seminar: Disjointness is hard in the multi-party number-on-the-forehead model

Adi Shraibman, Weizmann Institute of Science

Sunday, 20.01.2008, 11:00

Room 337-8 Taub Bld.

We show that disjointness requires randomized communication
Omega(n^{1/2k}/{(k-1)2^{k-1}2^{2^{k-1}})
in the general k-party number-on-the-forehead model of complexity. The
previous
best lower bound was Omega((log n)/k-1). By results of Beame, Pitassi, and
Segerlind, this implies 2^{n^{Omega(1)} lower bounds on the size of
tree-like Lovasz-Schrijver proof
systems needed to refute certain unsatisfiable CNFs, and
super-polynomial lower bounds on the
size of any tree-like p...

[ Full version ]

[ Full version ]

Learning From Related Sources

Koby Crammer

Tuesday, 15.01.2008, 14:30

Room 337-8 Taub Bld.

...

[ Full version ]

[ Full version ]

Recovering detailed 3D models of human shape and pose from images

Michael Black

Monday, 14.01.2008, 11:00

Taub 337

Algorithms for video-based human motion capture typically assume the body shape is known a priori and is represented coarsely (e.g. using cylinders to model body parts). These body models stand in sharp contrast to the richly detailed 3D body models used by by animators. In this talk we describe a method for recovering detailed body shape models directly from images. Specifically, we represent the body using a recently proposed triangulated mesh model called SCAPE which employs a ...

[ Full version ]

[ Full version ]

Multilinear Formulas, Maximal-Partition Discrepancy and Mixed-Sources Extra

Amir Yehudayoff

Sunday, 13.01.2008, 11:00

Room 337-8 Taub Bld.

In this paper we study multilinear formulas, monotone arithmetic circuits, maximal partition
discrepancy, best partition communication complexity and mixed two source extractors.
We will first define maximal partition discrepancy, and construct a function f that has
exponentially small maximal partition discrepancy. We will then review several application
of this construction:
1. The best partition communication complexity of f is \Theta(n).
...

[ Full version ]

[ Full version ]

Making large problems seem small: Convex duality in learning and inference

Amir Globerson

Thursday, 10.01.2008, 14:30

Room 337-8 Taub Bld.

...

[ Full version ]

[ Full version ]

Variational Image Restoration

Leah Bar

Thursday, 10.01.2008, 11:00

EE Meyer Building 1061

This research concerns the image deblurring and noise removal problem in a variational framework.
Energy functionals in this study consist of a fidelity term and a regularizer that is based on
Mumford-Shah segmentation, such that the recovered image and its discontinuities set are simultaneously
extracted in the course of the deblurring process. We first consider the image deblurring problem in
the presence of Gaussian/impulsive noise and present a convergence result for t...

[ Full version ]

[ Full version ]

Worst-case complexity vs. average-case complexity

Dan Gutfreund

Tuesday, 08.01.2008, 14:30

Room 337-8 Taub Bld.

...

[ Full version ]

[ Full version ]

The Role of Exemplars Comparison in Category Learning: The Emergence of Expertise

Rubi Hammer

Tuesday, 08.01.2008, 11:30

EE Meyer Building 1061

Recent studies stressed the importance of objects comparison for category learning. Recently we compared adults' capacity to learn new categorization principle in a condition in which few exemplars were identified as belong to the same category, versus a condition in which exemplars were identified as belong to different categories. We found that almost all participants learned the categorization rule quite efficiently in the Same-Class Exemplars condition. In contrast, when not p...

[ Full version ]

[ Full version ]

Integrative Biology and System-wide analyses in Tumor Formation

Sol Efroni

Sunday, 06.01.2008, 14:30

Room 337-8 Taub Bld.

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[ Full version ]

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3D Virtual Colonoscopy with Computer-Aided Polyp Detection

Arie Kaufman

Sunday, 06.01.2008, 11:30

EE Meyer Building 1061

This talk describes 3D virtual colonoscopy (VC), a combination of computed tomography (CT) scanning and volume visualization technology, and is poised to become the procedure of choice in lieu of the conventional optical colonoscopy for mass screening for colon cancer. The talk further discusses a novel pipeline of computer-aided detection (CAD) of colonic polyps – the precursor of colorectal cancer – complementing VC.
In VC, the patient abdomen is imaged by a helical CT scan...

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Cellular Developmental Decisions: From Single Cell Dynamics to Population Strategies

Iftach Nachman

Wednesday, 02.01.2008, 14:30

Room 337-8 Taub Bld.

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Sufficient conditions for local-to-global computations

Tali Kaufman

Tuesday, 01.01.2008, 14:30

Room 337-8 Taub Bld.

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Michael Bronstein

Tuesday, 01.01.2008, 11:30

EE Meyer Building 1061

Non-rigid shape similarity is an important problem in computer vision and pattern recognition. Broadly speaking, non-rigid shape similarity criteria are divided into intrinsic and extrinsic, the first referring to the metric structure of the objects and the latter to the geometry of the shapes in the Euclidean space. Both criteria have their advantages and disadvantages; extrinsic similarity is sensitive to non-rigid deformations of the shapes, while intrinsic similarity is sensit...

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[ Full version ]