Host: Dana Moshkovitz
The speaker will talk about applying theory to practice, with a focus on two IBM case studies. In the first case study, the practitioner initiated the interaction. This interaction led to the following problem. Assume that there is a set of “voters” and a set of “candidates”, where each voter assigns a numerical score to each candidate. There is a scoring function (such as the mean or the median), and a consensus ranking is obtained by applying the scoring function to each candidate’s scores. The problem is to find the top k candidates, while minimizing the number of database accesses. I will present an algorithm that is optimal in an extremely strong sense: not just in the worst case or the average case, but in every case! Even though the algorithm is only 10 lines long (!), the paper containing the algorithm won the 2014 Gödel Prize, the top prize for a paper in theoretical computer science.
The interaction in the second case study was initiated by theoreticians, who wanted to lay the foundations for “data exchange”, in which data is converted from one format to another. Although this problem may sound mundane, the issues that arise are fascinating, and this work made data exchange a new subfield, with special sessions in every major database conference.
This talk will be completely self-contained, and the speaker will derive morals from the case studies. The talk is aimed at both theoreticians and practitioners, to show them the mutual benefits of working together.
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UC San Diego
Galaxies grow through accretion of gas and mergers in their complex cosmological environ- ment. However, this growth needs to be regulated. Without additional "feedback" processes modeled galaxies end up too massive when compared to observed galaxies. I will present new cosmological simulations in FIRE project in which we have implemented physical feedback model from massive stars in the form of radiation pressure, stellar winds, supernovae and photo-ionization on local scales within the resolved interstellar medium.
Non-linear interaction of these mechanisms regulates the structure of the inter-stellar medium and galactic star formation and drives large scale galactic outflows. With the energy and momentum input from the standard population synthesis models our simulations produce galaxies with realistic stellar masses and star formation histories. During their evolution galaxies undergo episodic star formation and blow powerful galactic winds that remove galactic gas, interact with the circum-galactic medium and change properties of dark matter halos. I will discuss recent results from FIRE simulations, advantages of our physical feed- back back model with respect to previous sub-grid implementations and current limitations and future improvements in models of galaxy formation."
Sponsor: Kavli Institute for Astrophysics and Space Research
Dr. Eric Davis
Sponsored by: Center for International Studies
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Center for Mathematical Sciences
University of Cambridge
While much attention has been paid recently to the construction of optimal algorithms that adaptively estimate low-dimensional parameters (described by sparsity, low-rank, or smoothness) in high-dimensional models, the theory of statistical inference and uncertainty quantification (in particular hypothesis tests & confidence sets) is much less well-developed. We will discuss some perhaps surprising impossibility results in the basic high-dimensional compressed sensing model, and some of the recently remerging positive results in the area.
Richard Nickl is a mathematician working in the Statistical Laboratory within the Department of Pure Mathematics and Mathematical Statistics, at University of Cambridge. He is also a Fellow in Mathematics at Queens’ College. He works in the area of mathematical statistics, and his specific field is the mathematical theory of statistical inference in high- and infinite-dimensional models. His research reaches into and relies upon several other branches of mathematics, particularly probability theory and functional analysis. Richard Nickl is also an Associate Editor of the Bernoulli Journal and at the ESAIM Probability & Statistics.
Sponsor: Security Studies Program
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Christian Hansel, PhD
Professor, University of Chicago
Department of Neurobiology
Autism Spectrum Disorder (ASD) is defined by two characteristic symptoms, social interaction deficits and repetitive behaviors. An additional common feature is the impairment of motor control and learning, pointing towards a possible involvement of the cerebellum. To assess cerebellar abnormalities in ASD, we study motor behaviors and cerebellar synaptic plasticity in a mouse model for the human 15q11-13 duplication (patDp/+ mice), which is the most frequent genetic aberration in autism. These mice show ASD-resembling social behavior deficits. In my seminar, I will present our findings on alterations in synaptic connectivity, transmission and plasticity as well as motor learning in these mice, and will argue that the cerebellum—although not a usual suspect in autism—may hold some answers in autism research that might well guide research efforts in other brain areas.
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A panel discussion
This symposium will explore areas of mutual cooperation between MIT and Africans countries in areas of science, technology and innovation. The event will allow MIT to learn more about emerging trends in Africa and for Africa to familiarize itself with activities and MIT.
Moderator: Calestous Juma, Dr. Martin Luther King, Jr. Visiting Professor, Department of Urban Studies and Planning, MIT
Cosponsored by the Center for International Studies and the Department of Urban Studies and Planning; in cooperation with the MIT-Africa Program
The event is convened by MIT in partnership with the African Union's NEPAD Agency
Sponsored by: Department of Urban Studies and Planning, Center for International Studies, MIT-Africa Program
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Prof. Jan Rabaey