@phdthesis{8155, abstract = {In the thesis we focus on the interplay of the biophysics and evolution of gene regulation. We start by addressing how the type of prokaryotic gene regulation – activation and repression – affects spurious binding to DNA, also known as transcriptional crosstalk. We propose that regulatory interference caused by excess regulatory proteins in the dense cellular medium – global crosstalk – could be a factor in determining which type of gene regulatory network is evolutionarily preferred. Next,we use a normative approach in eukaryotic gene regulation to describe minimal non-equilibrium enhancer models that optimize so-called regulatory phenotypes. We find a class of models that differ from standard thermodynamic equilibrium models by a single parameter that notably increases the regulatory performance. Next chapter addresses the question of genotype-phenotype-fitness maps of higher dimensional phenotypes. We show that our biophysically realistic approach allows us to understand how the mechanisms of promoter function constrain genotypephenotype maps, and how they affect the evolutionary trajectories of promoters. In the last chapter we ask whether the intrinsic instability of gene duplication and amplification provides a generic alternative to canonical gene regulation. Using mathematical modeling, we show that amplifications can tune gene expression in many environments, including those where transcription factor-based schemes are hard to evolve or maintain. }, author = {Grah, Rok}, issn = {2663-337X}, pages = {310}, publisher = {Institute of Science and Technology Austria}, title = {{Gene regulation across scales – how biophysical constraints shape evolution}}, doi = {10.15479/AT:ISTA:8155}, year = {2020}, } @unpublished{7675, abstract = {In prokaryotes, thermodynamic models of gene regulation provide a highly quantitative mapping from promoter sequences to gene expression levels that is compatible with in vivo and in vitro bio-physical measurements. Such concordance has not been achieved for models of enhancer function in eukaryotes. In equilibrium models, it is difficult to reconcile the reported short transcription factor (TF) residence times on the DNA with the high specificity of regulation. In non-equilibrium models, progress is difficult due to an explosion in the number of parameters. Here, we navigate this complexity by looking for minimal non-equilibrium enhancer models that yield desired regulatory phenotypes: low TF residence time, high specificity and tunable cooperativity. We find that a single extra parameter, interpretable as the “linking rate” by which bound TFs interact with Mediator components, enables our models to escape equilibrium bounds and access optimal regulatory phenotypes, while remaining consistent with the reported phenomenology and simple enough to be inferred from upcoming experiments. We further find that high specificity in non-equilibrium models is in a tradeoff with gene expression noise, predicting bursty dynamics — an experimentally-observed hallmark of eukaryotic transcription. By drastically reducing the vast parameter space to a much smaller subspace that optimally realizes biological function prior to inference from data, our normative approach holds promise for mathematical models in systems biology.}, author = {Grah, Rok and Zoller, Benjamin and Tkačik, Gašper}, booktitle = {bioRxiv}, title = {{Normative models of enhancer function}}, doi = {10.1101/2020.04.08.029405}, year = {2020}, } @unpublished{8813, abstract = {In mammals, chromatin marks at imprinted genes are asymmetrically inherited to control parentally-biased gene expression. This control is thought predominantly to involve parent-specific differentially methylated regions (DMR) in genomic DNA. However, neither parent-of-origin-specific transcription nor DMRs have been comprehensively mapped. We here address this by integrating transcriptomic and epigenomic approaches in mouse preimplantation embryos (blastocysts). Transcriptome-analysis identified 71 genes expressed with previously unknown parent-of-origin-specific expression in blastocysts (nBiX: novel blastocyst-imprinted expression). Uniparental expression of nBiX genes disappeared soon after implantation. Micro-whole-genome bisulfite sequencing (μWGBS) of individual uniparental blastocysts detected 859 DMRs. Only 18% of nBiXs were associated with a DMR, whereas 60% were associated with parentally-biased H3K27me3. This suggests a major role for Polycomb-mediated imprinting in blastocysts. Five nBiX-clusters contained at least one known imprinted gene, and five novel clusters contained exclusively nBiX-genes. These data suggest a complex program of stage-specific imprinting involving different tiers of regulation.}, author = {Santini, Laura and Halbritter, Florian and Titz-Teixeira, Fabian and Suzuki, Toru and Asami, Maki and Ramesmayer, Julia and Ma, Xiaoyan and Lackner, Andreas and Warr, Nick and Pauler, Florian and Hippenmeyer, Simon and Laue, Ernest and Farlik, Matthias and Bock, Christoph and Beyer, Andreas and Perry, Anthony C. F. and Leeb, Martin}, booktitle = {bioRxiv}, title = {{Novel imprints in mouse blastocysts are predominantly DNA methylation independent}}, doi = {10.1101/2020.11.03.366948}, year = {2020}, } @unpublished{7601, abstract = {Plasmodesmata (PD) are crucial structures for intercellular communication in multicellular plants with remorins being their crucial plant-specific structural and functional constituents. The PD biogenesis is an intriguing but poorly understood process. By expressing an Arabidopsis remorin protein in mammalian cells, we have reconstituted a PD-like filamentous structure, termed remorin filament (RF), connecting neighboring cells physically and physiologically. Notably, RFs are capable of transporting macromolecules intercellularly, in a way similar to plant PD. With further super-resolution microscopic analysis and biochemical characterization, we found that RFs are also composed of actin filaments, forming the core skeleton structure, aligned with the remorin protein. This unique heterologous filamentous structure might explain the molecular mechanism for remorin function as well as PD construction. Furthermore, remorin protein exhibits a specific distribution manner in the plasma membrane in mammalian cells, representing a lipid nanodomain, depending on its lipid modification status. Our studies not only provide crucial insights into the mechanism of PD biogenesis, but also uncovers unsuspected fundamental mechanistic and evolutionary links between intercellular communication systems of plants and animals.}, author = {Wei, Zhuang and Tan, Shutang and Liu, Tao and Wu, Yuan and Lei, Ji-Gang and Chen, ZhengJun and Friml, Jiří and Xue, Hong-Wei and Liao, Kan}, booktitle = {bioRxiv}, pages = {22}, title = {{Plasmodesmata-like intercellular connections by plant remorin in animal cells}}, doi = {10.1101/791137}, year = {2020}, } @article{8539, abstract = {Cohomological and K-theoretic stable bases originated from the study of quantum cohomology and quantum K-theory. Restriction formula for cohomological stable bases played an important role in computing the quantum connection of cotangent bundle of partial flag varieties. In this paper we study the K-theoretic stable bases of cotangent bundles of flag varieties. We describe these bases in terms of the action of the affine Hecke algebra and the twisted group algebra of KostantKumar. Using this algebraic description and the method of root polynomials, we give a restriction formula of the stable bases. We apply it to obtain the restriction formula for partial flag varieties. We also build a relation between the stable basis and the Casselman basis in the principal series representations of the Langlands dual group. As an application, we give a closed formula for the transition matrix between Casselman basis and the characteristic functions.}, author = {Su, C. and Zhao, Gufang and Zhong, C.}, issn = {0012-9593}, journal = {Annales Scientifiques de l'Ecole Normale Superieure}, number = {3}, pages = {663--671}, publisher = {Societe Mathematique de France}, title = {{On the K-theory stable bases of the springer resolution}}, doi = {10.24033/asens.2431}, volume = {53}, year = {2020}, } @article{9781, abstract = {We consider the Pekar functional on a ball in ℝ3. We prove uniqueness of minimizers, and a quadratic lower bound in terms of the distance to the minimizer. The latter follows from nondegeneracy of the Hessian at the minimum.}, author = {Feliciangeli, Dario and Seiringer, Robert}, issn = {1095-7154}, journal = {SIAM Journal on Mathematical Analysis}, keywords = {Applied Mathematics, Computational Mathematics, Analysis}, number = {1}, pages = {605--622}, publisher = {Society for Industrial and Applied Mathematics}, title = {{Uniqueness and nondegeneracy of minimizers of the Pekar functional on a ball}}, doi = {10.1137/19m126284x}, volume = {52}, year = {2020}, } @phdthesis{8958, abstract = {The oft-quoted dictum by Arthur Schawlow: ``A diatomic molecule has one atom too many'' has been disavowed. Inspired by the possibility to experimentally manipulate and enhance chemical reactivity in helium nanodroplets, we investigate the rotation of coupled cold molecules in the presence of a many-body environment. In this thesis, we introduce new variational approaches to quantum impurities and apply them to the Fröhlich polaron - a quasiparticle formed out of an electron (or other point-like impurity) in a polar medium, and to the angulon - a quasiparticle formed out of a rotating molecule in a bosonic bath. With this theoretical toolbox, we reveal the self-localization transition for the angulon quasiparticle. We show that, unlike for polarons, self-localization of angulons occurs at finite impurity-bath coupling already at the mean-field level. The transition is accompanied by the spherical-symmetry breaking of the angulon ground state and a discontinuity in the first derivative of the ground-state energy. Moreover, the type of symmetry breaking is dictated by the symmetry of the microscopic impurity-bath interaction, which leads to a number of distinct self-localized states. For the system containing multiple impurities, by analogy with the bipolaron, we introduce the biangulon quasiparticle describing two rotating molecules that align with respect to each other due to the effective attractive interaction mediated by the excitations of the bath. We study this system from the strong-coupling regime to the weak molecule-bath interaction regime. We show that the molecules tend to have a strong alignment in the ground state, the biangulon shows shifted angulon instabilities and an additional spectral instability, where resonant angular momentum transfer between the molecules and the bath takes place. Finally, we introduce a diagonalization scheme that allows us to describe the transition from two separated angulons to a biangulon as a function of the distance between the two molecules.}, author = {Li, Xiang}, issn = {2663-337X}, pages = {125}, publisher = {Institute of Science and Technology Austria}, title = {{Rotation of coupled cold molecules in the presence of a many-body environment}}, doi = {10.15479/AT:ISTA:8958}, year = {2020}, } @inproceedings{15074, abstract = {We introduce a new graph problem, the token dropping game, and we show how to solve it efficiently in a distributed setting. We use the token dropping game as a tool to design an efficient distributed algorithm for the stable orientation problem, which is a special case of the more general locally optimal semi-matching problem. The prior work by Czygrinow et al. (DISC 2012) finds a locally optimal semi-matching in O(Δ⁵) rounds in graphs of maximum degree Δ, which directly implies an algorithm with the same runtime for stable orientations. We improve the runtime to O(Δ⁴) for stable orientations and prove a lower bound of Ω(Δ) rounds.}, author = {Brandt, Sebastian and Keller, Barbara and Rybicki, Joel and Suomela, Jukka and Uitto, Jara}, booktitle = {34th International Symposium on Distributed Computing}, location = {Virtual}, publisher = {Schloss Dagstuhl - Leibniz-Zentrum für Informatik}, title = {{Brief announcement: Efficient load-balancing through distributed token dropping}}, doi = {10.4230/LIPIcs.DISC.2020.40}, volume = {179}, year = {2020}, } @inproceedings{9415, abstract = {Optimizing convolutional neural networks for fast inference has recently become an extremely active area of research. One of the go-to solutions in this context is weight pruning, which aims to reduce computational and memory footprint by removing large subsets of the connections in a neural network. Surprisingly, much less attention has been given to exploiting sparsity in the activation maps, which tend to be naturally sparse in many settings thanks to the structure of rectified linear (ReLU) activation functions. In this paper, we present an in-depth analysis of methods for maximizing the sparsity of the activations in a trained neural network, and show that, when coupled with an efficient sparse-input convolution algorithm, we can leverage this sparsity for significant performance gains. To induce highly sparse activation maps without accuracy loss, we introduce a new regularization technique, coupled with a new threshold-based sparsification method based on a parameterized activation function called Forced-Activation-Threshold Rectified Linear Unit (FATReLU). We examine the impact of our methods on popular image classification models, showing that most architectures can adapt to significantly sparser activation maps without any accuracy loss. Our second contribution is showing that these these compression gains can be translated into inference speedups: we provide a new algorithm to enable fast convolution operations over networks with sparse activations, and show that it can enable significant speedups for end-to-end inference on a range of popular models on the large-scale ImageNet image classification task on modern Intel CPUs, with little or no retraining cost. }, author = {Kurtz, Mark and Kopinsky, Justin and Gelashvili, Rati and Matveev, Alexander and Carr, John and Goin, Michael and Leiserson, William and Moore, Sage and Nell, Bill and Shavit, Nir and Alistarh, Dan-Adrian}, booktitle = {37th International Conference on Machine Learning}, issn = {2640-3498}, location = {Online}, pages = {5533--5543}, title = {{Inducing and exploiting activation sparsity for fast neural network inference}}, volume = {119}, year = {2020}, } @article{8285, abstract = {We demonstrate the utility of optical cavity generated spin-squeezed states in free space atomic fountain clocks in ensembles of 390 000 87Rb atoms. Fluorescence imaging, correlated to an initial quantum nondemolition measurement, is used for population spectroscopy after the atoms are released from a confining lattice. For a free fall time of 4 milliseconds, we resolve a single-shot phase sensitivity of 814(61) microradians, which is 5.8(0.6) decibels (dB) below the quantum projection limit. We observe that this squeezing is preserved as the cloud expands to a roughly 200  μm radius and falls roughly 300  μm in free space. Ramsey spectroscopy with 240 000 atoms at a 3.6 ms Ramsey time results in a single-shot fractional frequency stability of 8.4(0.2)×10−12, 3.8(0.2) dB below the quantum projection limit. The sensitivity and stability are limited by the technical noise in the fluorescence detection protocol and the microwave system, respectively.}, author = {Malia, Benjamin K. and Martínez-Rincón, Julián and Wu, Yunfan and Hosten, Onur and Kasevich, Mark A.}, issn = {1079-7114}, journal = {Physical Review Letters}, number = {4}, publisher = {American Physical Society}, title = {{Free space Ramsey spectroscopy in rubidium with noise below the quantum projection limit}}, doi = {10.1103/PhysRevLett.125.043202}, volume = {125}, year = {2020}, } @article{8319, abstract = {We demonstrate that releasing atoms into free space from an optical lattice does not deteriorate cavity-generated spin squeezing for metrological purposes. In this work, an ensemble of 500000 spin-squeezed atoms in a high-finesse optical cavity with near-uniform atom-cavity coupling is prepared, released into free space, recaptured in the cavity, and probed. Up to ∼10 dB of metrologically relevant squeezing is retrieved for 700μs free-fall times, and decaying levels of squeezing are realized for up to 3 ms free-fall times. The degradation of squeezing results from loss of atom-cavity coupling homogeneity between the initial squeezed state generation and final collective state readout. A theoretical model is developed to quantify this degradation and this model is experimentally validated.}, author = {Wu, Yunfan and Krishnakumar, Rajiv and Martínez-Rincón, Julián and Malia, Benjamin K. and Hosten, Onur and Kasevich, Mark A.}, issn = {2469-9934}, journal = {Physical Review A}, number = {1}, publisher = {American Physical Society}, title = {{Retrieval of cavity-generated atomic spin squeezing after free-space release}}, doi = {10.1103/PhysRevA.102.012224}, volume = {102}, year = {2020}, } @article{8127, abstract = {Mechanistic modeling in neuroscience aims to explain observed phenomena in terms of underlying causes. However, determining which model parameters agree with complex and stochastic neural data presents a significant challenge. We address this challenge with a machine learning tool which uses deep neural density estimators—trained using model simulations—to carry out Bayesian inference and retrieve the full space of parameters compatible with raw data or selected data features. Our method is scalable in parameters and data features and can rapidly analyze new data after initial training. We demonstrate the power and flexibility of our approach on receptive fields, ion channels, and Hodgkin–Huxley models. We also characterize the space of circuit configurations giving rise to rhythmic activity in the crustacean stomatogastric ganglion, and use these results to derive hypotheses for underlying compensation mechanisms. Our approach will help close the gap between data-driven and theory-driven models of neural dynamics.}, author = {Gonçalves, Pedro J. and Lueckmann, Jan-Matthis and Deistler, Michael and Nonnenmacher, Marcel and Öcal, Kaan and Bassetto, Giacomo and Chintaluri, Chaitanya and Podlaski, William F. and Haddad, Sara A. and Vogels, Tim P and Greenberg, David S. and Macke, Jakob H.}, issn = {2050-084X}, journal = {eLife}, publisher = {eLife Sciences Publications}, title = {{Training deep neural density estimators to identify mechanistic models of neural dynamics}}, doi = {10.7554/eLife.56261}, volume = {9}, year = {2020}, } @article{22166, abstract = {We introduce a graph Ramsey game called Ramsey, Paper,Scissors. This game has two players, Proposer and Decider.Starting from an empty graph on n vertices, on each turnProposer proposes a potential edge and Decider simultane-ously decides (without knowing Proposer’s choice) whether toadd it to the graph. Proposer cannot propose an edge whichwould create a triangle in the graph. The game ends whenProposer has no legal moves remaining, and Proposer wins ifthe final graph has independence number at least s. We provea threshold phenomenon exists for this game by exhibitingrandomized strategies for both players that are optimal up toconstants. Namely, there exist constants 0 < A < B such that(under optimal play) Proposer wins with high probability ifs < A√n log n, while Decider wins with high probability ifs > B√n log n. This is a factor of Θ(√log n)) larger than thelower bound coming from the off-diagonal Ramsey numberr(3, s).}, author = {Fox, Jacob and He, Xiaoyu and Wigderson, Yuval}, issn = {1098-2418}, journal = {Random Structures & Algorithms}, number = {4}, pages = {1157--1173}, publisher = {Wiley}, title = {{Ramsey, Paper, Scissors}}, doi = {10.1002/rsa.20950}, volume = {57}, year = {2020}, } @article{22182, abstract = {We present a short new proof of the canonical polynomial van der Waerden theorem, recently established by Girão.}, author = {Fox, Jacob and Wigderson, Yuval and Zhao, Yufei}, issn = {1778-3569}, journal = {Comptes Rendus Mathématique}, number = {8}, pages = {957--959}, publisher = {Académie des Sciences}, title = {{A short proof of the canonical polynomial van der Waerden theorem}}, doi = {10.5802/crmath.101}, volume = {358}, year = {2020}, } @article{22185, abstract = {A weakly optimal Ks-free (n,d,λ)-graph is ad-regular Ks-free graph on n vertices with d= Θ(n1−α) and spectral expansion λ= Θ(n1−(s−1)α), for some fixed α >0. Such a graph is called optimal if additionally α=12s−3. We prove that if s1,...,sk>3 are fixed positive integers and weakly optimal Ksi-free pseudorandom graphs exist for each 10. Such a graph is called optimal if additionally α=12s−3. We prove that if s1,…,sk≥3 are fixed positive integers and weakly optimal Ksi-free pseudorandom graphs exist for each 1≤i≤k, then the multicolor Ramsey numbers satisfy Ω(tS+1log2St)≤r(s1,…,sk,t)≤O(tS+1logSt), as t→∞, where S=∑ki=1(si−2). This generalizes previous results of Mubayi and Verstraëte, who proved the case k=1, and Alon and Rödl, who proved the case s1=⋯=sk=3. Both previous results used the existence of optimal rather than weakly optimal Ksi-free graphs.}, author = {He, Xiaoyu and Wigderson, Yuval}, issn = {1077-8926}, journal = {The Electronic Journal of Combinatorics}, number = {1}, publisher = {The Electronic Journal of Combinatorics}, title = {{Multicolor Ramsey numbers via pseudorandom graphs}}, doi = {10.37236/9071}, volume = {27}, year = {2020}, } @article{7467, abstract = {Nanomaterials produced from the bottom-up assembly of nanocrystals may incorporate ∼1020–1021 cm–3 not fully coordinated surface atoms, i.e., ∼1020–1021 cm–3 potential donor or acceptor states that can strongly affect transport properties. Therefore, to exploit the full potential of nanocrystal building blocks to produce functional nanomaterials and thin films, a proper control of their surface chemistry is required. Here, we analyze how the ligand stripping procedure influences the charge and heat transport properties of sintered PbSe nanomaterials produced from the bottom-up assembly of colloidal PbSe nanocrystals. First, we show that the removal of the native organic ligands by thermal decomposition in an inert atmosphere leaves relatively large amounts of carbon at the crystal interfaces. This carbon blocks crystal growth during consolidation and at the same time hampers charge and heat transport through the final nanomaterial. Second, we demonstrate that, by stripping ligands from the nanocrystal surface before consolidation, nanomaterials with larger crystal domains, lower porosity, and higher charge carrier concentrations are obtained, thus resulting in nanomaterials with higher electrical and thermal conductivities. In addition, the ligand displacement leaves the nanocrystal surface unprotected, facilitating oxidation and chalcogen evaporation. The influence of the ligand displacement on the nanomaterial charge transport properties is rationalized here using a two-band model based on the standard Boltzmann transport equation with the relaxation time approximation. Finally, we present an application of the produced functional nanomaterials by modeling, fabricating, and testing a simple PbSe-based thermoelectric device with a ring geometry.}, author = {Cadavid, Doris and Ortega, Silvia and Illera, Sergio and Liu, Yu and Ibáñez, Maria and Shavel, Alexey and Zhang, Yu and Li, Mengyao and López, Antonio M. and Noriega, Germán and Durá, Oscar Juan and López De La Torre, M. A. and Prades, Joan Daniel and Cabot, Andreu}, issn = {2574-0962}, journal = {ACS Applied Energy Materials}, number = {3}, pages = {2120--2129}, publisher = {American Chemical Society}, title = {{Influence of the ligand stripping on the transport properties of nanoparticle-based PbSe nanomaterials}}, doi = {10.1021/acsaem.9b02137}, volume = {3}, year = {2020}, } @phdthesis{8589, abstract = {The plant hormone auxin plays indispensable roles in plant growth and development. An essential level of regulation in auxin action is the directional auxin transport within cells. The establishment of auxin gradient in plant tissue has been attributed to local auxin biosynthesis and directional intercellular auxin transport, which both are controlled by various environmental and developmental signals. It is well established that asymmetric auxin distribution in cells is achieved by polarly localized PIN-FORMED (PIN) auxin efflux transporters. Despite the initial insights into cellular mechanisms of PIN polarization obtained from the last decades, the molecular mechanism and specific regulators mediating PIN polarization remains elusive. In this thesis, we aim to find novel players in PIN subcellular polarity regulation during Arabidopsis development. We first characterize the physiological effect of piperonylic acid (PA) on Arabidopsis hypocotyl gravitropic bending and PIN polarization. Secondly, we reveal the importance of SCFTIR1/AFB auxin signaling pathway in shoot gravitropism bending termination. In addition, we also explore the role of myosin XI complex, and actin cytoskeleton in auxin feedback regulation on PIN polarity. In Chapter 1, we give an overview of the current knowledge about PIN-mediated auxin fluxes in various plant tropic responses. In Chapter 2, we study the physiological effect of PA on shoot gravitropic bending. Our results show that PA treatment inhibits auxin-mediated PIN3 repolarization by interfering with PINOID and PIN3 phosphorylation status, ultimately leading to hyperbending hypocotyls. In Chapter 3, we provide evidence to show that the SCFTIR1/AFB nuclear auxin signaling pathway is crucial and required for auxin-mediated PIN3 repolarization and shoot gravitropic bending termination. In Chapter 4, we perform a phosphoproteomics approach and identify the motor protein Myosin XI and its binding protein, the MadB2 family, as an essential regulator of PIN polarity for auxin-canalization related developmental processes. In Chapter 5, we demonstrate the vital role of actin cytoskeleton in auxin feedback on PIN polarity by regulating PIN subcellular trafficking. Overall, the data presented in this PhD thesis brings novel insights into the PIN polar localization regulation that resulted in the (re)establishment of the polar auxin flow and gradient in response to environmental stimuli during plant development.}, author = {Han, Huibin}, issn = {2663-337X}, pages = {164}, publisher = {Institute of Science and Technology Austria}, title = {{Novel insights into PIN polarity regulation during Arabidopsis development}}, doi = {10.15479/AT:ISTA:8589}, year = {2020}, } @inproceedings{8322, abstract = {Reverse firewalls were introduced at Eurocrypt 2015 by Miro-nov and Stephens-Davidowitz, as a method for protecting cryptographic protocols against attacks on the devices of the honest parties. In a nutshell: a reverse firewall is placed outside of a device and its goal is to “sanitize” the messages sent by it, in such a way that a malicious device cannot leak its secrets to the outside world. It is typically assumed that the cryptographic devices are attacked in a “functionality-preserving way” (i.e. informally speaking, the functionality of the protocol remains unchanged under this attacks). In their paper, Mironov and Stephens-Davidowitz construct a protocol for passively-secure two-party computations with firewalls, leaving extension of this result to stronger models as an open question. In this paper, we address this problem by constructing a protocol for secure computation with firewalls that has two main advantages over the original protocol from Eurocrypt 2015. Firstly, it is a multiparty computation protocol (i.e. it works for an arbitrary number n of the parties, and not just for 2). Secondly, it is secure in much stronger corruption settings, namely in the active corruption model. More precisely: we consider an adversary that can fully corrupt up to 𝑛−1 parties, while the remaining parties are corrupt in a functionality-preserving way. Our core techniques are: malleable commitments and malleable non-interactive zero-knowledge, which in particular allow us to create a novel protocol for multiparty augmented coin-tossing into the well with reverse firewalls (that is based on a protocol of Lindell from Crypto 2001).}, author = {Chakraborty, Suvradip and Dziembowski, Stefan and Nielsen, Jesper Buus}, booktitle = {Advances in Cryptology – CRYPTO 2020}, isbn = {9783030568795}, issn = {1611-3349}, location = {Santa Barbara, CA, United States}, pages = {732--762}, publisher = {Springer Nature}, title = {{Reverse firewalls for actively secure MPCs}}, doi = {10.1007/978-3-030-56880-1_26}, volume = {12171}, year = {2020}, } @inproceedings{7636, abstract = {Balanced search trees typically use key comparisons to guide their operations, and achieve logarithmic running time. By relying on numerical properties of the keys, interpolation search achieves lower search complexity and better performance. Although interpolation-based data structures were investigated in the past, their non-blocking concurrent variants have received very little attention so far. In this paper, we propose the first non-blocking implementation of the classic interpolation search tree (IST) data structure. For arbitrary key distributions, the data structure ensures worst-case O(log n + p) amortized time for search, insertion and deletion traversals. When the input key distributions are smooth, lookups run in expected O(log log n + p) time, and insertion and deletion run in expected amortized O(log log n + p) time, where p is a bound on the number of threads. To improve the scalability of concurrent insertion and deletion, we propose a novel parallel rebuilding technique, which should be of independent interest. We evaluate whether the theoretical improvements translate to practice by implementing the concurrent interpolation search tree, and benchmarking it on uniform and nonuniform key distributions, for dataset sizes in the millions to billions of keys. Relative to the state-of-the-art concurrent data structures, the concurrent interpolation search tree achieves performance improvements of up to 15% under high update rates, and of up to 50% under moderate update rates. Further, ISTs exhibit up to 2X less cache-misses, and consume 1.2 -- 2.6X less memory compared to the next best alternative on typical dataset sizes. We find that the results are surprisingly robust to distributional skew, which suggests that our data structure can be a promising alternative to classic concurrent search structures.}, author = {Brown, Trevor A and Prokopec, Aleksandar and Alistarh, Dan-Adrian}, booktitle = {Proceedings of the ACM SIGPLAN Symposium on Principles and Practice of Parallel Programming}, isbn = {9781450368186}, location = {San Diego, CA, United States}, pages = {276--291}, publisher = {Association for Computing Machinery}, title = {{Non-blocking interpolation search trees with doubly-logarithmic running time}}, doi = {10.1145/3332466.3374542}, year = {2020}, }