December 2021 - talks - lists.cs.princeton.edu

Asiff Hirji lecture rescheduled to Feb 1, 2022
by Emily C. Lawrence 26 Jan '22

26 Jan '22

Speaker: ASIFF HIRJI, President of Figure and Former President and COO of Coinbase Title: DeFi and How Blockchain will Transform Financial Services Day: Tuesday, February 1, 2022 Time: 4:30 pm to 5:30 pm Location: Arthur Lewis Auditorium – Robertson Hall Host: Princeton’s Bendheim Center for Finance, the Julis Rabinowitz Center for Public Policy & Finance, and the Center for Information Technology Policy Open to: Princeton University students, faculty and staff. Event and Registration Page: [ https://bcf.princeton.edu/events/defi-and-how-blockchain-will-transform-fin… | https://bcf.princeton.edu/events/defi-and-how-blockchain-will-transform-fin… ] Abstract: Asiff Hirji, President of Figure Technologies and former President & COO of Coinbase and TD Ameritrade discusses how blockchain, and the DeFi movement, will transform financial services. Through the provision of an immutable ledger, public registry and real-time bilateral transaction settlement capability, the application of blockchain technology will meaningfully reduce the risk, cost and capital requirements associated with current financial systems and infrastructure as well as eliminate the need for most financial intermediaries. The implications for the financial industry will be profound, please join us to learn more. Bio: Asiff Hirji is President of Figure Technologies, Inc. (Figure™), a leader in transforming financial services through the power of blockchain technology. He recently served as President and COO of Coinbase where he grew the company to over $1 billion in revenue; launched new businesses; built out the management team and achieved an $8 billion valuation. Prior to Coinbase, Hirji was an Operating Partner with Andreesen Horowitz focused on helping their best companies scale faster. He previously served as President and COO of TD Ameritrade, growing that business 6x into the nation’s largest online broker. Hirji has also held senior leadership roles with TPG Capital, Saxo Bank, HP, and Bain Capital and has served on a number of public and private boards including Citrix and Advent Software.

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Dale Lee will present her MSE talk, "The Effect of Early vs Late Ventilation on Survival on COVID-19 Patients" on December 21, 2021 at 2pm via Zoom.
by Nicki Mahler 17 Dec '21

17 Dec '21

Dale Lee will present her MSE talk, "The Effect of Early vs Late Ventilation on Survival on COVID-19 Patients" on December 21, 2021 at 2pm via Zoom. Zoom link: [ https://princeton.zoom.us/j/7738327530 | https://princeton.zoom.us/j/7738327530 ] Committee members: Barbara Engelhardt (Adviser), Ben Raphael (Reader) All are welcome to attend. Abstract: How can you determine when a COVID-19 patient needs to be intubated? Mechanical ventilation is a procedure taken for patients who are critically ill and are unable to maintain an adequate blood oxygen level with other supportive oxygen devices. However, there is limited evidence to guide physicians on optimal timing for this procedure. This paper takes a closer look at the trajectories of patients who are ventilated and attempts to draw insights on the ideal timing for mechanical ventilation.

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Chaitanya Aluru will present his FPO "Reconciliation-Based Methods for Identifying the Evolutionary Origins of Tandem Duplications in Repeat Domain Families" on Friday, 12/17/2021 at 1:30PM via Zoom and CS 105
by Nicki Mahler 14 Dec '21

14 Dec '21

Chaitanya Aluru will present his FPO "Reconciliation-Based Methods for Identifying the Evolutionary Origins of Tandem Duplications in Repeat Domain Families" on Friday, 12/17/2021 at 1:30PM via Zoom and in CS 105 Zoom link: https://princeton.zoom.us/j/99860934740 The members of his committee are as follows: Mona Singh (Adviser), Readers: Ben Raphael, Bernard Chazelle, Mona Singh; Examiners: Mona Singh, Olga Troyanskaya, and Barbara Engelhardt A copy of his thesis is available upon request. Please email gradinfo(a)cs.princeton.edu if you would like a copy of the thesis. Everyone is invited to attend the talk. Abstract follows below: Domains are the structural, functional, and evolutionary building blocks of protein sequences. Proteins can contain multiple domain instances, and duplications and losses of these domains are a key driver of protein evolution. Of particular interest are families of proteins with consecutive repeats of the same domain. These tandem repeat families are involved in a wide variety of functions, including transcriptional regulation, protein transport, muscle contraction, brain size regulation, and many others. Proteins with tandemly repeated domains form a significant portion of the proteome across the tree of life. Despite their prevalence and importance, the evolutionary histories and functional diversification of many of these protein families are largely unknown. Understanding when domains duplicate, whether individually or together as part of an array of domains, could yield deeper insights into the functions of these proteins. Several attempts have been made to understand the evolution of repeat domains within protein sequences. These approaches can largely be categorized into sequence-based and reconciliation-based methods. Sequence-based approaches attempt to identify the existence of tandem duplications, without placing them in an evolutionary context. Reconciliation based methods, on the other hand, use gene and domain trees to simultaneously infer both tandem duplication events and the genes they occurred in. These methods, while more powerful, have not accurately captured tandem duplication events. In this work, we bridge the gap between these two methods, developing reconciliationbased methods that can accurately identify tandem domain duplication events while also placing them correctly in the evolutionary history of their gene families. We extend existing reconciliation frameworks to include flexible cost models for duplication events. Rather than fixed costs regardless of duplication size, we represent costs as arbitrary functions of duplication length. We tackle the problem of distinguishing tandem duplications from other duplication events by incorporating sequence position information from existing domains. We provide both exact solutions and fast, accurate heuristics to these problems. Finally, we apply these approaches to the largest repeat domain family in humans, the Cys2-His2 zinc fingers. In analysis of 494 Cys2-His2 zinc finger orthogroups, we find evidence of numerous tandem domain duplications throughout the placental mammals.

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Jiaqi Su will present his Pre FPO "Studio Quality Speech Enhancement" on Thursday, December 16, 2021 at 3pm via Zoom
by Nicki Mahler 13 Dec '21

13 Dec '21

Jiaqi Su will present his Pre FPO "Studio Quality Speech Enhancement" on Thursday, December 16, 2021 at 3pm via Zoom Zoom Link https://princeton.zoom.us/j/6073737365 Committee: Examiners: Adam Finkelstein (advisor), Olga Russakovsky, Karthik Narasimhan Readers: Szymon Rusinkiewicz, Zeyu Jin Abstract: Modern speech content creation tasks such as podcasts, video voice-overs, and audio books require studio-quality audio with full bandwidth and balanced equalization. However, real-world recordings captured in natural spaces with consumer-grade devices suffer from noise, reverberation, equalization distortion and bandwidth limitations. The goal of cleaning up such recordings poses a challenge for conventional speech enhancement methods, which typically focus on removing strong acoustic degradations so as to improve speech clarity and intelligibility, but fall short of studio quality. In this talk, I will present an end-to-end deep learning approach for transforming recorded speech to sound as though it had been recorded in a studio. The approach relies on a multi-domain multi-scale GAN, coupled with deep feature matching in the discriminators, to model the perception of sound quality. It also incorporates a separate pre-trained recurrent neural network to predict the acoustic features of the clean target from those of noisy input, which serves as a guide to generate the clean audio. This combined approach incorporates the effectiveness of acoustic features in modeling human perception of speech, while retaining the benefits of waveform-to-waveform conversion. I will first show the model in the context of speech enhancement at 16kHz, and then discuss how to adapt the approach to bandwidth extension for filling in missing high frequency details at 48kHz. These two components placed together form a full studio-quality speech enhancement pipeline for real-world recordings. Finally, with access to a studio quality version of the recording, we can optionally repurpose components of this pipeline to adapt the recording so that it matches the acoustic qualities of a specific target environment.

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Matthew Weaver will present his Pre FPO "Bicubical Directed Type Theory" on Friday, December 10, 2021 via zoom
by Nicki Mahler 09 Dec '21

09 Dec '21

Matthew Weaver will present his Pre FPO "Bicubical Directed Type Theory" on Friday, December 10, 2021 via zoom. Zoom Link: https://princeton.zoom.us/j/93770491933?pwd=S0g5TW9OR0xEenFOOHBGeHdkK29rdz09 Meeting ID: 937 7049 1933 Passcode: 110745 Committee: Andrew Appel (Advisor) Daniel Licata (Reader) Zachary Kincaid (Reader) David Walker (Examiner) Aarti Gupta (Examiner) Title: Bicubical Directed Type Theory Abstract: In homotopy type theory, each type is equipped with an abstract notion of path, corresponding to the morphisms of a higher groupoid. Voevodsky's univalence axiom states that the type of paths between types is equivalent (a generalization of isomorphism) to the type of equivalences between types, and can be seen as extending type theory with a generic program for lifting equivalences between types along any type family. Defining this lifting for all dependent types is quite subtle, but univalence has recently been given a computational interpretation in various cubical type theories. A natural question is whether there are any directed analogues of homotopy type theory, where types are equipped with a notion of directed morphism and correspond to higher categories, generalizing groupoids. In such a setting, one possible directed analogue of univalence would circumscribe a class of type constructors that represent covariant functors, and provide a means to automatically lift a function or directed morphism along such a type constructor. Directed type theory with directed univalence has some potential applications to computer science that are not possible in ordinary homotopy type theory, such as providing a convenient language for coding the functorial specification of abstract syntax. One approach to directed type theory, developed by Riehl and Shulman, is based on equipping each type with both a notion of path and a separate notion of directed morphism. While ordinary homotopy type theory has models in simplicial sets (a model of homotopy types) the Riehl-Shulman type theory is based on a model in bisimplicial sets, capturing these two notions of path and directed morphism. While this suffices for formalizing mathematics, for applications to computer science we would like a computational interpretation of the type theory, and it is not yet known whether there are constructive models of standard homotopy type theory in simplicial sets. Thus, in this thesis, we instead consider a cubical setting, and give a constructive model of a directed type theory with directed univalence in bicubical sets. We formalize much of this model using Agda as the internal language of a 1-topos, following Orton and Pitts. First, building on the cubical techniques used to give computational models of homotopy type theory, we show that there is a universe of covariant discrete fibrations (covariant functors valued in types that themselves have trivial morphism structure), with a partial directed univalence principle asserting that functions are a retract of morphisms in this universe. To complete this retraction into an equivalence, we refine the model using some recent work on constructive sheaf models by Coquand, Ruch, and Sattler, which builds on Shulman's characterization of fibrations in injective model structures as algebras for the cobar construction. Concretely, this means equipping each fibrant type with an additional operation (an equivalence with the cobar construction on it), from which the final part of the directed univalence equivalence can be defined. In the presence of directed univalence, one would additionally hope for a theory containing directed higher inductive types (DHITs). These types allow for one to inductively define types containing directed structure, and in conjunction with directed univalence allow for novel proof techniques in verification; in particular, the combination allows one to directly formalize functorial semantics using the internal categorical structure of types. We introduce a schema for DHITs based off of the schema for higher inductive types in cubical type theory by Cavallo and Harper. As a part of this work, we additionally define schemas for regular inductive types and higher inductive types. Lastly, we demonstrate how DHITs can be used with directed univalence to encode functorial semantics for formal verification.

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Austin Hounsel will present his Pre FPO “Measuring the Feasibility of DNS Privacy and Security” on Tuesday, December 7th, 2021 at 12pm via Zoom
by Nicki Mahler 03 Dec '21

03 Dec '21

Austin Hounsel will present his Pre FPO “Measuring the Feasibility of DNS Privacy and Security” on Tuesday, December 7th, 2021 at 12pm via Zoom. Zoom link: https://princeton.zoom.us/j/93647966696 <https://princeton.zoom.us/j/93647966696> - Nick Feamster (advisor): non-reader - Jennifer Rexford: non-reader - Ravi Netravali: non-reader - Prateek Mittal: reader - Kyle Jamieson: reader Abstract: "Virtually every device on the Internet relies on the Domain Name System (DNS) to translate human-readable names to IP addresses. Originally, the DNS was designed without security and privacy concerns in mind. This has left users’ DNS traffic subject to eavesdropping, tampering, and censorship. In response, encrypted DNS protocols and DNS Security Extensions (DNSSEC) have seen increased deployment. Although these technologies are designed to improve users’ security and privacy, two key questions remain unanswered. First, it is unclear whether encrypted DNS protocols yield acceptable performance for popular applications, such as web browsers. Second, it is unclear whether users can reliably retrieve the DNS records that are necessary for client-side DNSSEC validation. Without answers to these questions, popular application developers are unable to determine the feasibility and value of deploying these technologies. This thesis studies the feasibility and value of deploying DNS security and privacy technologies through various Internet measurements. We first present performance measurements of encrypted DNS protocols from data centers and home networks. We not only measure query response times, but also web page load times to understand how these protocols might impact popular applications that issue numerous queries. We find that although encrypted DNS protocols generally result in longer query response times than traditional, unencrypted DNS, these protocols can result in faster page load times. Our work suggests that users don’t need to trade DNS performance for privacy. On the other hand, we also find that the security value of implementing client-side DNSSEC validation is questionable. We present a collaboration with a major browser vendor to measure how often browser users can successfully retrieve DNS records that are necessary for client-side DNSSEC validation. To do so, we deploy a measurement add-on to a global distribution of 5% of the browser’s beta users. The add-on issues queries for various DNS records under a domain name that we control using the browser's locally configured recursive resolver. We find that users were unable to retrieve the correct DNS records they needed to perform client-side DNSSEC validation across approximately 1/3rd of the measurements. Thus, applications may not obtain additional security from DNSSEC beyond querying a recursive resolver that supports it."

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