cssi/SciSciGPT-SciSciNet huggingface dataset:
A Confidence-Based Approach for Balancing Fairness and Accuracy.

We study three classical machine learning algorithms in the context of algorithmic fairness: adaptive boosting, support vector machines, and logistic regression. Our goal is to maintain the high accuracy of these learning algorithms while reducing the degree to which they discriminate against individuals because of their membership in a protected group. Our first contribution is a method for achieving fairness by shifting the decision boundary for the protected group. The method is based on the theory of margins for boosting. Our method performs comparably to or outperforms previous algorithms in the fairness literature in terms of accuracy and low discrimination, while simultaneously allowing for a fast and transparent quantification of the trade-off between bias and error. Our second contribution addresses the shortcomings of the bias-error trade-off studied in most of the algorithmic fairness literature. We demonstrate that even hopelessly naive modifications of a biased algorithm, which cannot be reasonably said to be fair, can still achieve low bias and high accuracy. To help to distinguish between these naive algorithms and more sensible algorithms we propose a new measure of fairness, called resilience to random bias (RRB). We demonstrate that RRB distinguishes well between our naive and sensible fairness algorithms. RRB together with bias and accuracy provides a more complete picture of the fairness of an algorithm.
Computational Analysis of Inspiratory and Expiratory Flow in the Lung Airway

Inspiratory and expiratory flow in a multi-generation pig lung airway was numerically studied at a peak tracheal flow rate corresponding to a Reynolds number of 1150. The model was validated by comparing velocity distributions with previous measurements for a simple airway bifurcation. Simulation results at different cross sections of the airway tree provided detailed maps of the axial and secondary flow patterns. Flow at the main bifurcation and in many other bifurcations showed complex secondary flow structures. The flow morphology in the pig airways differed from that of simplified bifurcation airway models and that of humans, which is likely due to the large differences in the airway geometry of the different species. The inspiratory pressure drop was calculated, and simulation results suggested that the viscous pressure drop values were comparable to earlier studies in human airway geometries. The reported differences between pig and human airways need to be taken into consideration when generalizing results of animal experiments to humans.
Eliminating timing side-channel leaks using program repair

We propose a method, based on program analysis and transformation, for eliminating timing side channels in software code that implements security-critical applications. Our method takes as input the original program together with a list of secret variables (e.g., cryptographic keys, security tokens, or passwords) and returns the transformed program as output. The transformed program is guaranteed to be functionally equivalent to the original program and free of both instruction- and cache-timing side channels. Specifically, we ensure that the number of CPU cycles taken to execute any path is independent of the secret data, and the cache behavior of memory accesses, in terms of hits and misses, is independent of the secret data. We have implemented our method in LLVM and validated its effectiveness on a large set of applications, which are cryptographic libraries with 19,708 lines of C/C++ code in total. Our experiments show the method is both scalable for real applications and effective in eliminating timing side channels.
Synchronization Strings: List Decoding for Insertions and Deletions

We study codes that are list-decodable under insertions and deletions ("insdel codes"). Specifically, we consider the setting where, given a codeword x of length n over some finite alphabet Sigma of size q, delta * n codeword symbols may be adversarially deleted and gamma * n symbols may be adversarially inserted to yield a corrupted word w. A code is said to be list-decodable if there is an (efficient) algorithm that, given w, reports a small list of codewords that include the original codeword x. Given delta and gamma we study what is the rate R for which there exists a constant q and list size L such that there exist codes of rate R correcting delta-fraction insertions and gamma-fraction deletions while reporting lists of size at most L. Using the concept of synchronization strings, introduced by the first two authors [Proc. STOC 2017], we show some surprising results. We show that for every 0 0 there exist codes of rate 1 - delta - epsilon and constant alphabet (so q = O_{delta,gamma,epsilon}(1)) and sub-logarithmic list sizes. Furthermore, our codes are accompanied by efficient (polynomial time) decoding algorithms. We stress that the fraction of insertions can be arbitrarily large (more than 100%), and the rate is independent of this parameter. We also prove several tight bounds on the parameters of list-decodable insdel codes. In particular, we show that the alphabet size of insdel codes needs to be exponentially large in epsilon^{-1}, where epsilon is the gap to capacity above. Our result even applies to settings where the unique-decoding capacity equals the list-decoding capacity and when it does so, it shows that the alphabet size needs to be exponentially large in the gap to capacity. This is sharp contrast to the Hamming error model where alphabet size polynomial in epsilon^{-1} suffices for unique decoding. This lower bound also shows that the exponential dependence on the alphabet size in previous works that constructed insdel codes is actually necessary! Our result sheds light on the remarkable asymmetry between the impact of insertions and deletions from the point of view of error-correction: Whereas deletions cost in the rate of the code, insertion costs are borne by the adversary and not the code! Our results also highlight the dominance of the model of insertions and deletions over the Hamming model: A Hamming error is equal to one insertion and one deletion (at the same location). Thus the effect of delta-fraction Hamming errors can be simulated by delta-fraction of deletions and delta-fraction of insertions - but insdel codes can deal with much more insertions without loss in rate (though at the price of higher alphabet size).
Switchable polar spirals in tricolor oxide superlattices

Abstract There are increasing evidences that ferroelectric states at the nanoscale can exhibit fascinating topological structures including polar vortices and skyrmions, akin to those observed in the ferromagnetic systems. Here we report the discovery of a new type of polar topological structure, an ordered array of nanoscale spirals, in the PbTiO3/BiFeO3/SrTiO3 tricolor ferroelectric superlattice system obtained via phase-field simulations. This polar spiral structure is composed of fine ordered semi-vortex arrays with vortex cores forming a wavy distribution. It is demonstrated that the tricolor system has an ultrahigh Curie temperature of ∼1000 K and a temperature of ∼800 K for the phase transformation from spiral structure to in-plane orthorhombic domain structure, demonstrating a great thermal stability. The periodicity phase-diagram is constructed, showing multiple phases from inplane domain, polar spiral, and polar vortex to flux-closure with increasing ferroelectric layer thickness. Moreover, the spiral structure has a net in-plane polarization that could be switched by an experimentally-feasible irrotational in-plane field. The switching process involves a metastable vortex state and is fully reversible. This discovery could open up a new routine to design novel multiferroic topological structures with enhanced stability and tunability towards potential future applications in next-generation electronics.
The category of F-modules has finite global dimension

Abstract Let R be a regular ring of characteristic p > 0 . In [4] , Hochster showed that the category of Lyubeznikʼs F R -modules has enough injectives, so that every F R -module has an injective resolution in this category. We show in this paper that under mild conditions on R, for example when R is essentially of finite type over an F-finite regular local ring, the category of F-modules has finite global dimension d + 1 where d = dim R . In [4] , Hochster also showed that when M and N are F R -finite F R -modules, Hom F R ( M , N ) is finite. We show that in general Ext F R 1 ( M , N ) is not necessarily finite.
On quantum groups associated to non-Noetherian regular algebras of dimension 2

We investigate homological and ring-theoretic properties of universal quantum linear groups that coact on Artin-Schelter regular algebras A(n) of global dimension 2, especially with central homological codeterminant (or central quantum determinant). As classified by Zhang, the algebras A(n) are connected $$\mathbb {N}$$ -graded algebras that are finitely generated by n indeterminants of degree 1, subject to one quadratic relation. In the case when the homological codeterminant of the coaction is trivial, we show that the quantum group of interest, defined independently by Manin and by Dubois-Violette and Launer, is Artin-Schelter regular of global dimension 3 and also skew Calabi-Yau (homologically smooth of dimension 3). For central homological codeterminant, we verify that the quantum groups are Noetherian and have finite Gelfand-Kirillov dimension precisely when the corresponding comodule algebra A(n) satisfies these properties, that is, if and only if $$n=2$$ . We have similar results for arbitrary homological codeterminant if we require that the quantum groups are involutory. We also establish conditions when Hopf quotients of these quantum groups, that also coact on A(n), are cocommutative.
The Deodhar decomposition of the Grassmannian and the regularity of KP solitons

Abstract Given a point A in the real Grassmannian, it is well-known that one can construct a soliton solution u A ( x , y , t ) to the KP equation. The contour plot of such a solution provides a tropical approximation to the solution when the variables x , y , and t are considered on a large scale and the time t is fixed. In this paper we use several decompositions of the Grassmannian in order to gain an understanding of the contour plots of the corresponding soliton solutions. First we use the positroid stratification of the real Grassmannian in order to characterize the unbounded line-solitons in the contour plots at y ≫ 0 and y ≪ 0 . Next we use the Deodhar decomposition of the Grassmannian–a refinement of the positroid stratification–to study contour plots at t ≪ 0 . More specifically, we index the components of the Deodhar decomposition of the Grassmannian by certain tableaux which we call Go-diagrams , and then use these Go-diagrams to characterize the contour plots of solitons solutions when t ≪ 0 . Finally we use these results to show that a soliton solution u A ( x , y , t ) is regular for all times t if and only if A comes from the totally non-negative part of the Grassmannian.
U-Phylogeny: Undirected provenance graph construction in the wild

Deriving relationships between images and tracing back their history of modifications are at the core of Multimedia Phylogeny solutions, which aim to combat misinformation through doctored visual media. Nonetheless, most recent image phylogeny solutions cannot properly address cases of forged composite images with multiple donors, an area known as multiple parenting phylogeny (MPP). This paper presents a preliminary undirected graph construction solution for MPP, without any strict assumptions. The algorithm is underpinned by robust image representative keypoints and different geometric consistency checks among matching regions in both images to provide regions of interest for direct comparison. The paper introduces a novel technique to geometrically filter the most promising matches as well as to aid in the shared region localization task. The strength of the approach is corroborated by experiments with real-world cases, with and without image distractors (unrelated cases).
Predicting the supremum: optimality of 'stop at once or not at all'

Let (Xt)0≤t≤T be a one-dimensional stochastic process with independent and stationary increments, either in discrete or continuous time. This paper considers the problem of stopping the process (Xt) “as close as possible” to its eventual supremum MT := sup 0≤t≤T Xt, when the reward for stopping at time � � T is a nonincreasing convex function of MT X�. Under fairly general conditions on the process (Xt), it is shown that the optimal stopping ˜
Secure and private cloud storage systems with random linear fountain codes

An information theoretic approach to security and privacy called Secure And Private Information Retrieval (SAPIR) is introduced. SAPIR is applied to distributed data storage systems. In this approach, random combinations of all contents are stored across the network. Our coding approach is based on Random Linear Fountain (RLF) codes. To retrieve a content, a group of servers collaborate with each other to form a Reconstruction Group (RG). SAPIR achieves asymptotic perfect secrecy if at least one of the servers within an RG is not compromised. Further, a Private Information Retrieval (PIR) scheme based on random queries is proposed. The PIR approach ensures the users privately download their desired contents without the servers knowing about the requested contents indices. The proposed scheme is adaptive and can provide privacy against a significant number of colluding servers.
Gated-Attention Readers for Text Comprehension

In this paper we study the problem of answering cloze-style questions over documents. Our model, the Gated-Attention (GA) Reader, integrates a multi-hop architecture with a novel attention mechanism, which is based on multiplicative interactions between the query embedding and the intermediate states of a recurrent neural network document reader. This enables the reader to build query-specific representations of tokens in the document for accurate answer selection. The GA Reader obtains state-of-the-art results on three benchmarks for this task–the CNN & Daily Mail news stories and the Who Did What dataset. The effectiveness of multiplicative interaction is demonstrated by an ablation study, and by comparing to alternative compositional operators for implementing the gated-attention.
Transition from Static to Dynamic Macroscopic Friction in the Framework of the Frenkel- Kontorova Model

Abstract A new generation of experiments on dry macroscopic friction has revealed that the transition from static to dynamic friction is essentially a spatially and temporally non-uniform process, initiated by a rupture-like detachment front. We show the suitability of the Frenkel–Kontorova model for describing this transition. The model predicts the existence of two types of detachment fronts, explaining both the variability and abrupt change of velocity observed in experiments. The quantitative relation obtained between the velocity of the detachment front and the ratio of shear to normal stress is consistent with experiments. The model provides relations between kinematic and dynamic parameters of the transition process.
On the cohomology of the Weyl algebra, the quantum plane, and the q-Weyl algebra

Abstract Deformation theory can be used to compute the cohomology of a deformed algebra with coefficients in itself from that of the original. Using the invariance of the Euler–Poincare characteristic under deformation, it is applied here to compute the cohomology of the Weyl algebra, the algebra of the quantum plane, and the q -Weyl algebra. The behavior of the cohomology when q is a root of unity may encode some number theoretic information.
Stochastic solution of fractional Fokker–Planck equations with space–time-dependent coefficients

Abstract This paper develops solutions of fractional Fokker–Planck equations describing subdiffusion of probability densities of stochastic dynamical systems driven by non-Gaussian Levy processes, with space–time-dependent drift, diffusion and jump coefficients, thus significantly extends Magdziarz and Zorawik's result in [14] . Fractional Fokker–Planck equation describing subdiffusion is solved by our result in full generality from perspective of stochastic representation.
On semistability of CAT(0) groups

Does every one-ended $CAT(0)$ group have semistable fundamental group at infinity? As we write, this is an open question. Let $G$ be such a group acting geometrically on the proper $CAT(0)$ space $X$. In this paper we show that in order to establish a positive answer to the question it is only necessary to check that any two geodesic rays in $X$ are properly homotopic. We then show that if the answer to the question is negative, with $(G,X)$ a counter-example, then the boundary of $X$, $\del X$ with the cone topology, must have a weak cut point. This is of interest because a theorem of Papasoglu and the second-named author \cite{PS} has established that there cannot be an example of $(G,X)$ where $\del X$ has a cut point. Thus, the search for a negative answer comes down to the difference between cut points and weak cut points. We also show that the Tits ball of radius $\frac{\pi}{2}$ about that weak cut point is a "cut set" in the sense that it separates $\del X$. Finally, we observe that if a negative example $(G, X)$ exists then $G$ is rank 1.
Strongly Hermitian Einstein–Maxwell solutions on ruled surfaces

This paper produces explicit strongly Hermitian Einstein–Maxwell solutions on the smooth compact 4-manifolds that are $$S^2$$ -bundles over compact Riemann surfaces of any genus. This generalizes the existence results by LeBrun (J Geom Phys 91:163–171, 2015, The Einstein–Maxwell equations and conformally Kaehler geometry. arXiv:1504.06669 , 2016). Moreover, by calculating the (normalized) Einstein–Hilbert functional of our examples, we generalize Theorem E of LeBrun (The Einstein–Maxwell equations and conformally Kaehler geometry. arXiv:1504.06669 , 2016), which speaks to the abundance of Hermitian Einstein–Maxwell solutions on such manifolds. As a bonus, we exhibit certain pairs of strongly Hermitian Einstein–Maxwell solutions, first found in LeBrun (The Einstein–Maxwell equations and conformally Kaehler geometry. arXiv:1504.06669 , 2016), on the first Hirzebruch surface in a form which clearly shows that they are conformal to a common Kahler metric. In particular, this yields a non-trivial example of non-uniqueness of positive constant scalar curvature metrics in a given conformal class.
HECKE-TYPE CONGRUENCES FOR TWO SMALLEST PARTS FUNCTIONS

We prove infinitely many congruences modulo 3, 5, and powers of 2 for the overpartition function and two smallest parts functions: for overpartitions and M2spt(n) for partitions without repeated odd parts. These resemble the Hecke-type congruences found by Atkin for the partition function p(n) in 1966 and Garvan for the smallest parts function spt(n) in 2010. The proofs depend on congruences between the generating functions for , , and M2spt(n) and eigenforms for the half-integral weight Hecke operator T(l2).
Pipeline implementations of Neumann–Neumann and Dirichlet–Neumann waveform relaxation methods

This paper is concerned with the reformulation of Neumann–Neumann waveform relaxation (NNWR) methods and Dirichlet–Neumann waveform relaxation (DNWR) methods, a family of parallel space-time approaches to solving time-dependent PDEs. By changing the order of the operations, pipeline-parallel computation of the waveform iterates are possible, without changing the solution of each waveform iterate. The parallel efficiency of the pipeline implementation is analyzed, as well as the change in the communication pattern. Numerical studies are presented to show the effectiveness of the pipeline NNWR and DNWR algorithms.
On a Perturbation Determinant for Accumulative Operators

For a purely imaginary sign-definite perturbation of a self-adjoint operator, we obtain exponential representations for the perturbation determinant in both upper and lower half-planes and derive respective trace formulas.
Octopus: A Framework for Cost-Quality-Time Optimization in Crowdsourcing

We present Octopus, an AI agent to jointly balance three conflicting task objectives on a micro-crowdsourcing marketplace – the quality of work, total cost incurred, and time to completion. Previous control agents have mostly focused on cost-quality, or cost-time tradeoffs, but not on directly controlling all three in concert. A naive formulation of three-objective optimization is intractable; Octopus takes a hierarchical POMDP approach, with three different components responsible for setting the pay per task, selecting the next task, and controlling task-level quality. We demonstrate that Octopus significantly outperforms existing state-of-the-art approaches on real experiments. We also deploy Octopus on Amazon Mechanical Turk, showing its ability to manage tasks in a real-world, dynamic setting.
On the Hodge–Newton filtration for p -divisible groups of Hodge type

A p-divisible group, or more generally an F-crystal, is said to be Hodge–Newton reducible if its Newton polygon and Hodge polygon have a nontrivial contact point. Katz proved that Hodge–Newton reducible F-crystals admit a canonical filtration called the Hodge–Newton filtration. The notion of Hodge–Newton reducibility plays an important role in the deformation theory of p-divisible groups; the key property is that the Hodge–Newton filtration of a p-divisible group over a field of characteristic p can be uniquely lifted to a filtration of its deformation. We generalize Katz’s result to F-crystals that arise from an unramified local Shimura datum of Hodge type. As an application, we give a generalization of Serre–Tate deformation theory for local Shimura data of Hodge type.
Citation Statistics From More Than a Century of Physical Review

We study the statistics of citations from all Physical Review journals for the 110-year period 1893 until 2003. We discuss basic properties of the citation distribution and find that the growth of citations is consistent with linear preferential attachment. We also investigate how citations evolve with time. There is a positive correlation between the number of citations to a paper and the average age of citations. Citations from a publication have an exponentially decaying age distribution; that is, old papers tend to not get cited. In contrast, the citations to a publication are consistent with a power-law age distribution, with an exponent close to −1 over a time range of 2 – 20 years. We also identify one exceptionally strong burst of citations, as well as other dramatic features in the time history of citations to individual publications.
Notions of robust information coding

We introduce and study several notions of computability-theoretic reducibility between subsets of ω that are “robust” in the sense that if only partial information is available about the oracle, then partial information can be recovered about the output. These are motivated by reductions between Π2 principles in the context of reverse mathematics (where some of our results have already been applied, in the work of Hirschfeldt and Jockusch [3]), and also encompasses generic and coarse reducibilities (previously studied by Jockusch
SELF-SUPERVISED ANOMALY DETECTION FOR NARROWBAND SETI

The Search for Extra-terrestrial Intelligence (SETI) aims to find technological signals of extra-solar origin. Radio frequency SETI is characterized by large unlabeled datasets and complex interference environment. The infinite possibilities of potential signal types require generalizable signal processing techniques with little human supervision. We present a generative model of self-supervised deep learning that can be used for anomaly detection and spatial filtering. We develop and evaluate our approach on spectrograms containing narrowband signals collected by Breakthrough Listen at the Green Bank telescope. The proposed approach is not meant to replace current narrowband searches but to demonstrate the potential to generalize to other signal types.
A characterization of the prime graphs of solvable groups

Abstract Let π ( G ) denote the set of prime divisors of the order of a finite group G. The prime graph of G, denoted Γ G , is the graph with vertex set π ( G ) with edges { p , q } ∈ E ( Γ G ) if and only if there exists an element of order pq in G. In this paper, we prove that a graph is isomorphic to the prime graph of a solvable group if and only if its complement is 3-colorable and triangle-free. We then introduce the idea of a minimal prime graph. We prove that there exists an infinite class of solvable groups whose prime graphs are minimal. We prove the 3k-conjecture on prime divisors in element orders for solvable groups with minimal prime graphs, and we show that solvable groups whose prime graphs are minimal have Fitting length 3 or 4.
Learning Joint Semantic Parsers from Disjoint Data

We present a new approach to learning a semantic parser from multiple datasets, even when the target semantic formalisms are drastically different and the underlying corpora do not overlap. We handle such “disjoint” data by treating annotations for unobserved formalisms as latent structured variables. Building on state-of-the-art baselines, we show improvements both in frame-semantic parsing and semantic dependency parsing by modeling them jointly.
Computational Limits for Matrix Completion

Matrix Completion is the problem of recovering an unknown real-valued low-rank matrix from a subsample of its entries. Important recent results show that the problem can be solved efficiently under the assumption that the unknown matrix is incoherent and the subsample is drawn uniformly at random. Are these assumptions necessary? It is well known that Matrix Completion in its full generality is NP-hard. However, little is known if we make additional assumptions such as incoherence and permit the algorithm to output a matrix of slightly higher rank. In this paper we prove that Matrix Completion remains computationally intractable even if the unknown matrix has rank 4 but we are allowed to output any constant rank matrix, and even if additionally we assume that the unknown matrix is incoherent and are shown 90% of the entries. This result relies on the conjectured hardness of the 4-Coloring problem. We also consider the positive semidefinite Matrix Completion problem. Here we show a similar hardness result under the standard assumption that P 6= NP. Our results greatly narrow the gap between existing feasibility results and computational lower bounds. In particular, we believe that our results give the first complexity-theoretic justification for why distributional assumptions are needed beyond the incoherence assumption in order to obtain positive results. On the technical side, we contribute several new ideas on how to encode hard combinatorial problems in low-rank optimization problems. We hope that these techniques will be helpful in further understanding the computational limits of Matrix Completion and related problems.
Current eigenmodes and dephasing in nanoscopic quantum networks

© 2012 by American Physical Society , Physical Review B. The original version is available through American Physical Society at DOI: 10.1103/PhysRevB.85.195459
Linear Block Coding for Efficient Beam Discovery in Millimeter Wave Communication Networks

The surge in mobile broadband data demands is expected to surpass the available spectrum capacity below 6 GHz. This expectation has prompted the exploration of millimeter wave (mm-wave) frequency bands as a candidate technology for next generation wireless networks. However, numerous challenges to deploying mm-wave communication systems, including channel estimation, need to be met before practical deployments are possible. This work addresses the mm-wave channel estimation problem and treats it as a beam discovery problem in which locating beams with strong path reflectors is analogous to locating errors in linear block codes. We show that a significantly small number of measurements (compared to the original dimensions of the channel matrix) is sufficient to reliably estimate the channel. We also show that this can be achieved using a simple and energy-efficient transceiver architecture.
A Constrained Optimization Problem for the Fourier Transform: Quantitative Analysis

Among functions f majorized by indicator functions $$1_E$$ , which functions have maximal ratio $$\Vert {\widehat{f}}\Vert _q/|E|^{1/p}$$ ? We establish a quantitative answer to this question for exponents q sufficiently close to even integers, building on previous work proving the existence of such maximizers.
Berge duals and universally tight contact structures

Abstract Dehn surgery on a knot determines a dual knot in the surgered manifold, the core of the filling torus. We consider duals of knots in S 3 that have a lens space surgery. Each dual supports a contact structure. We show that if a universally tight contact structure is supported, then the dual is in the same homology class as the dual of a torus knot.
A Grammar for Reproducible and Painless Extract-Transform-Load Operations on Medium Data

ABSTRACTMany interesting datasets available on the Internet are of a medium size—too big to fit into a personal computer’s memory, but not so large that they would not fit comfortably on its hard disk. In the coming years, datasets of this magnitude will inform vital research in a wide array of application domains. However, due to a variety of constraints they are cumbersome to ingest, wrangle, analyze, and share in a reproducible fashion. These obstructions hamper thorough peer-review and thus disrupt the forward progress of science. We propose a predictable and pipeable framework for R (the state-of-the-art statistical computing environment) that leverages SQL (the venerable database architecture and query language) to make reproducible research on medium data a painless reality. Supplementary material for this article is available online.
Rotated eigenstructure analysis for source localization without energy-decay models

Herein, the problem of simultaneous localization of two sources given a modest number of samples is examined. In particular, the strategy does not require knowledge of the target signatures of the sources a priori, nor does it exploit classical methods based on a particular decay rate of the energy emitted from the sources as a function of range. General structural properties of the signatures such as unimodality are exploited. The algorithm localizes targets based on the rotated eigenstructure of a reconstructed observation matrix. In particular, the optimal rotation can be found by maximizing the ratio of the dominant singular value of the observation matrix over the nuclear norm of the optimally rotated observation matrix. It is shown that this ratio has a unique local maximum leading to computationally efficient search algorithms. Moreover, analytical results are developed to show that the squared localization error decreases at a rate n−3 for a Gaussian field with a single source, where n(log n)2 scales proportionally to the number of samples M.
Global smooth and topological rigidity of hyperbolic lattice actions

In this article we prove global rigidity results for hyperbolic actions of higher-rank lattices. Suppose $\Gamma$ is a lattice in semisimple Lie group, all of whose factors have rank $2$ or higher. Let $\alpha$ be a smooth $\Gamma$-action on a compact nilmanifold $M$ that lifts to an action on the universal cover. If the linear data $\rho$ of $\alpha$ contains a hyperbolic element, then there is a continuous semiconjugacy intertwining the actions of $\alpha$ and $\rho$, on a finite-index subgroup of $\Gamma$. If $\alpha$ is a $C^\infty$ action and contains an Anosov element, then the semiconjugacy is a $C^\infty$ conjugacy. As a corollary, we obtain $C^\infty$ global rigidity for Anosov actions by cocompact lattices in semisimple Lie group with all factors rank $2$ or higher. We also obtain global rigidity of Anosov actions of $\mathrm{SL}(n,\mathbb Z)$ on $\mathbb T^n$ for $ n\geq 5$ and probability-preserving Anosov actions of arbitrary higher-rank lattices on nilmanifolds.
Computing complex and real tropical curves using monodromy

Abstract Tropical varieties capture combinatorial information about how coordinates of points in a classical variety approach zero or infinity. We present algorithms for computing the rays of a complex and real tropical curve defined by polynomials with constant coefficients. These algorithms rely on homotopy continuation, monodromy loops, and Cauchy integrals. Several examples are presented which are computed using an implementation that builds on the numerical algebraic geometry software Bertini .
Wave functions of the Q · Q interaction in terms of unitary 9- j coefficients

We obtain wave functions for two protons and two neutrons in the ${g}_{9/2}$ shell expressed as column vectors with amplitudes $D({J}_{p},{J}_{n})$. When we use a quadrupole-quadrupole interaction $(Q\ifmmode\cdot\else\textperiodcentered\fi{}Q)$ we get, in many cases, a very strong overlap with wave functions given by a single set of unitary 9-$j$ coefficients---$\mathrm{U}9j=\ensuremath{\langle}{(jj)}^{2j}{(j{j}^{{J}_{B}}|{(jj)}^{{J}_{p}}{(jj)}^{{J}_{n}})}^{I}\ensuremath{\rangle}$. Here ${J}_{B}=9$ for even $IT=0$ states. For both even and odd $T=1$ states we take ${J}_{B}$ equal to 8 whilst for odd $I,T=0$ we take ${J}_{B}$ to be 7. We compare the $Q\ifmmode\cdot\else\textperiodcentered\fi{}Q$ results with those of a more realistic interaction.
A 0–1 law for the massive Gaussian free field

We investigate the phase transition in a non-planar correlated percolation model with long-range dependence, obtained by considering level sets of a Gaussian free field with mass above a given height h. The dependence present in the model is a notorious impediment when trying to analyze the behavior near criticality. Alongside the critical threshold $$h_*$$ for percolation, a second parameter $$h_{**} \ge h_*$$ characterizes a strongly subcritical regime. We prove that the relevant crossing probabilities converge to 1 polynomially fast below $$h_{**}$$ , which (firmly) suggests that the phase transition is sharp. A key tool is the derivation of a suitable differential inequality for the free field that enables the use of a (conditional) influence theorem.
Reduced Space and Faster Convergence in Imperfect-Information Games via Regret-Based Pruning.

Counterfactual Regret Minimization (CFR) is the most popular iterative algorithm for solving zero-sum imperfect-information games. Regret-Based Pruning (RBP) is an improvement that allows poorly-performing actions to be temporarily pruned, thus speeding up CFR. We introduce Total RBP, a new form of RBP that reduces the space requirements of CFR as actions are pruned. We prove that in zero-sum games it asymptotically prunes any action that is not part of a best response to some Nash equilibrium. This leads to provably faster convergence and lower space requirements. Experiments show that Total RBP results in an order of magnitude reduction in space, and the reduction factor increases with game size.
Community Detection and Classification in Hierarchical Stochastic Blockmodels

In disciplines as diverse as social network analysis and neuroscience, many large graphs are believed to be composed of loosely connected smaller graph primitives, whose structure is more amenable to analysis We propose a robust, scalable, integrated methodology for community detection and community comparison in graphs. In our procedure, we first embed a graph into an appropriate Euclidean space to obtain a low-dimensional representation, and then cluster the vertices into communities. We next employ nonparametric graph inference techniques to identify structural similarity among these communities. These two steps are then applied recursively on the communities, allowing us to detect more fine-grained structure. We describe a hierarchical stochastic blockmodel —namely, a stochastic blockmodel with a natural hierarchical structure—and establish conditions under which our algorithm yields consistent estimates of model parameters and motifs , which we define to be stochastically similar groups of subgraphs. Finally, we demonstrate the effectiveness of our algorithm in both simulated and real data. Specifically, we address the problem of locating similar sub-communities in a partially reconstructed Drosophila connectome and in the social network Friendster.
Radiometric Scene Decomposition: Scene Reflectance, Illumination, and Geometry from RGB-D Images

Recovering the radiometric properties of a scene (i.e., the reflectance, illumination, and geometry) is a long-sought ability of computer vision that can provide invaluable information for a wide range of applications. Deciphering the radiometric ingredients from the appearance of a real-world scene, as opposed to a single isolated object, is particularly challenging as it generally consists of various objects with different material compositions exhibiting complex reflectance and light interactions that are also part of the illumination. We introduce the first method for radiometric decomposition of real-world scenes that handles those intricacies. We use RGB-D images to bootstrap geometry recovery and simultaneously recover the complex reflectance and natural illumination while refining the noisy initial geometry and segmenting the scene into different material regions. Most important, we handle real-world scenes consisting of multiple objects of unknown materials, which necessitates the modeling of spatially-varying complex reflectance, natural illumination, texture, interreflection and shadows. We systematically evaluate the effectiveness of our method on synthetic scenes and demonstrate its application to real-world scenes. The results show that rich radiometric information can be recovered from RGB-D images and demonstrate a new role RGB-D sensors can play for general scene understanding tasks.
Formal Analysis of Linear Control Systems Using Theorem Proving.

Control systems are an integral part of almost every engineering and physical system and thus their accurate analysis is of utmost importance. Traditionally, control systems are analyzed using paper-and-pencil proof and computer simulation methods, however, both of these methods cannot provide accurate analysis due to their inherent limitations. Model checking has been widely used to analyze control systems but the continuous nature of their environment and physical components cannot be truly captured by a state-transition system in this technique. To overcome these limitations, we propose to use higher-order-logic theorem proving for analyzing linear control systems based on a formalized theory of the Laplace transform method. For this purpose, we have formalized the foundations of linear control system analysis in higher-order logic so that a linear control system can be readily modeled and analyzed. The paper presents a new formalization of the Laplace transform and the formal verification of its properties that are frequently used in the transfer function based analysis to judge the frequency response, gain margin and phase margin, and stability of a linear control system. We also formalize the active realizations of various controllers, like Proportional-Integral-Derivative (PID), Proportional-Integral (PI), Proportional-Derivative (PD), and various active and passive compensators, like lead, lag and lag-lead. For illustration, we present a formal analysis of an unmanned free-swimming submersible vehicle using the HOL Light theorem prover.
A Generalized Gaussian Process Model for Computer Experiments With Binary Time Series

Non-Gaussian observations such as binary responses are common in some computer experiments. Motivated by the analysis of a class of cell adhesion experiments, we introduce a generalized Gaussian pr...
Mindful Active Learning.

We propose a novel active learning framework for activity recognition using wearable sensors. Our work is unique in that it takes physical and cognitive limitations of the oracle into account when selecting sensor data to be annotated by the oracle. Our approach is inspired by human-beings' limited capacity to respond to external stimulus such as responding to a prompt on their mobile devices. This capacity constraint is manifested not only in the number of queries that a person can respond to in a given time-frame but also in the lag between the time that a query is made and when it is responded to. We introduce the notion of mindful active learning and propose a computational framework, called EMMA, to maximize the active learning performance taking informativeness of sensor data, query budget, and human memory into account. We formulate this optimization problem, propose an approach to model memory retention, discuss complexity of the problem, and propose a greedy heuristic to solve the problem. We demonstrate the effectiveness of our approach on three publicly available datasets and by simulating oracles with various memory strengths. We show that the activity recognition accuracy ranges from 21% to 97% depending on memory strength, query budget, and difficulty of the machine learning task. Our results also indicate that EMMA achieves an accuracy level that is, on average, 13.5% higher than the case when only informativeness of the sensor data is considered for active learning. Additionally, we show that the performance of our approach is at most 20% less than experimental upper-bound and up to 80% higher than experimental lower-bound. We observe that mindful active learning is most beneficial when query budget is small and/or oracle's memory is weak, thus emphasizing contributions of our work in human-centered mobile health settings and for elderly with cognitive impairments.
The Effects of Ambiguity on Loss Contingency Evaluation by Auditors and Investors

ABSTRACT The objective of this study is to provide additional evidence regarding the effect of ambiguity on auditors' and investors' judgments when they evaluate managers' disclosures about loss co...
Robotic Detection of Marine Litter Using Deep Visual Detection Models

Trash deposits in aquatic environments have a destructive effect on marine ecosystems and pose a long-term economic and environmental threat. Autonomous underwater vehicles (AUVs) could very well contribute to the solution of this problem by finding and eventually removing trash. This paper evaluates a number of deep-learning algorithms performing the task of visually detecting trash in realistic underwater environments, with the eventual goal of exploration, mapping, and extraction of such debris by using AUVs. A large and publicly-available dataset of actual debris in open-water locations is annotated for training a number of convolutional neural network architectures for object detection. The trained networks are then evaluated on a set of images from other portions of that dataset, providing insight into approaches for developing the detection capabilities of an AUV for underwater trash removal. In addition, the evaluation is performed on three different platforms of varying processing power, which serves to assess these algorithms’ fitness for real-time applications.
Reference governors and maximal output admissible sets for linear periodic systems

ABSTRACTIn this paper, we consider the problem of constraint management in Linear Periodic (LP) systems using Reference Governors (RG). First, we introduce the periodic-invariant maximal output adm...
Regulation of Cyclin E by transcription factors of the naïve pluripotency network in mouse embryonic stem cells.

Continuous, non-cell cycle-dependent expression of cyclin E is a characteristic feature of mouse embryonic stem cells (mESCs). We studied the 5' regulatory region of Cyclin E, also known as Ccne1, and identified binding sites for transcription factors of the naive pluripotency network, including Esrrb, Klf4, and Tfcp2l1 within 1 kilobase upstream of the transcription start site. Luciferase assay and chromatin immunoprecipitation-quantitative polymerase chain reaction (ChiP-qPCR) study highlighted one binding site for Esrrb that is essential to transcriptional activity of the promoter region, and three binding sites for Klf4 and Tfcp2l1. Knockdown of Esrrb, Klf4, and Tfcp2l1 reduced Cyclin E expression whereas overexpression of Esrrb and Klf4 increased it, indicating a strong correlation between the expression level of these factors and that of cyclin E. We observed that cyclin E overexpression delays differentiation induced by Esrrb depletion, suggesting that cyclin E is an important target of Esrrb for differentiation blockade. We observed that mESCs express a low level of miR-15a and that transfection of a miR-15a mimic decreases Cyclin E mRNA level. These results lead to the conclusion that the high expression level of Cyclin E in mESCs can be attributed to transcriptional activation by Esrrb as well as to the absence of its negative regulator, miR-15a.
My reference point, not yours

Abstract Reference points formed by initial endowments influence individual decisions. This experiment tests whether an individual can predict the behavior of other people who have different reference points. Despite financial incentives for being correct, players fail to imagine themselves in another person’s shoes. A low endowment player generally cannot predict the behavior of those who were assigned high endowments, and vice versa, when asked about group behavior. Instead of considering the perspectives of others, a low endowment player predicts that all others will act as if they all had low endowments. This controlled experiment helps explain why it is difficult to understand the perspectives of other people, while also demonstrating that it is possible when a player is specifically prompted to consider an individual in a different circumstance.
Cities of Workers, Children, or Seniors? Age Structure and Economic Growth in a Global Cross-Section of Cities

A large literature documents the positive influence of a city's skill structure on its rate of economic growth. By contrast, the effect of a city's age structure on its economic growth has been a hitherto largely neglected area of research. This paper hypothesizes that cities with more working-age adults are likely to grow faster than cities with more children or seniors. The paper sets out the potential channels through which such differential growth may occur. Using data from a variety of historical and contemporary sources, it shows that there exists marked variation in the age structure of the world's largest cities, across cities and over time. It then studies how age structure affects economic growth for a global cross-section of mega-cities. Using various identification strategies, the analysis finds that mega-cities with higher dependency ratios, that is, with more children and/or seniors per working-age adult, grow significantly slower. Such effects are particularly pronounced for cities with high shares of children. This result appears to be driven mainly by the direct, negative effects of a higher dependency ratio on the size of the working-age population and the indirect effects on work hours and productivity for working-age adults within a city.