90

On the automorphic sheaves for GSp_4. (arXiv:1901.04447v6 [math.RT] UPDATED)

In this paper we first review the setting for the geometric Langlands functoriality and establish a result for the `backward' functoriality functor. We illustrate this by known examples of the geometric theta-lifting. We then apply the above result to obtain new Hecke eigen-sheaves. The most important application is a construction of the automorphic sheaf for G=GSp_4 attached to a G^L-local system on a curve X such that its standard representation is an irreducible local system of rank 4 on X.




90

Local mollification of Riemannian metrics using Ricci flow, and Ricci limit spaces. (arXiv:1706.09490v2 [math.DG] UPDATED)

We use Ricci flow to obtain a local bi-Holder correspondence between Ricci limit spaces in three dimensions and smooth manifolds. This is more than a complete resolution of the three-dimensional case of the conjecture of Anderson-Cheeger-Colding-Tian, describing how Ricci limit spaces in three dimensions must be homeomorphic to manifolds, and we obtain this in the most general, locally non-collapsed case. The proofs build on results and ideas from recent papers of Hochard and the current authors.




90

Filtered expansions in general relativity II. (arXiv:2005.03390v1 [math-ph])

This is the second of two papers in which we construct formal power series solutions in external parameters to the vacuum Einstein equations, implementing one bounce for the Belinskii-Khalatnikov-Lifshitz (BKL) proposal for spatially inhomogeneous spacetimes. Here we show that spatially inhomogeneous perturbations of spatially homogeneous elements are unobstructed. A spectral sequence for a filtered complex, and a homological contraction based on gauge-fixing, are used to do this.




90

GraphBLAST: A High-Performance Linear Algebra-based Graph Framework on the GPU. (arXiv:1908.01407v3 [cs.DC] CROSS LISTED)

High-performance implementations of graph algorithms are challenging to implement on new parallel hardware such as GPUs, because of three challenges: (1) difficulty of coming up with graph building blocks, (2) load imbalance on parallel hardware, and (3) graph problems having low arithmetic intensity. To address these challenges, GraphBLAS is an innovative, on-going effort by the graph analytics community to propose building blocks based in sparse linear algebra, which will allow graph algorithms to be expressed in a performant, succinct, composable and portable manner. In this paper, we examine the performance challenges of a linear algebra-based approach to building graph frameworks and describe new design principles for overcoming these bottlenecks. Among the new design principles is exploiting input sparsity, which allows users to write graph algorithms without specifying push and pull direction. Exploiting output sparsity allows users to tell the backend which values of the output in a single vectorized computation they do not want computed. Load-balancing is an important feature for balancing work amongst parallel workers. We describe the important load-balancing features for handling graphs with different characteristics. The design principles described in this paper have been implemented in "GraphBLAST", the first open-source linear algebra-based graph framework on GPU targeting high-performance computing. The results show that on a single GPU, GraphBLAST has on average at least an order of magnitude speedup over previous GraphBLAS implementations SuiteSparse and GBTL, comparable performance to the fastest GPU hardwired primitives and shared-memory graph frameworks Ligra and Gunrock, and better performance than any other GPU graph framework, while offering a simpler and more concise programming model.




90

Watching the World Go By: Representation Learning from Unlabeled Videos. (arXiv:2003.07990v2 [cs.CV] UPDATED)

Recent single image unsupervised representation learning techniques show remarkable success on a variety of tasks. The basic principle in these works is instance discrimination: learning to differentiate between two augmented versions of the same image and a large batch of unrelated images. Networks learn to ignore the augmentation noise and extract semantically meaningful representations. Prior work uses artificial data augmentation techniques such as cropping, and color jitter which can only affect the image in superficial ways and are not aligned with how objects actually change e.g. occlusion, deformation, viewpoint change. In this paper, we argue that videos offer this natural augmentation for free. Videos can provide entirely new views of objects, show deformation, and even connect semantically similar but visually distinct concepts. We propose Video Noise Contrastive Estimation, a method for using unlabeled video to learn strong, transferable single image representations. We demonstrate improvements over recent unsupervised single image techniques, as well as over fully supervised ImageNet pretraining, across a variety of temporal and non-temporal tasks. Code and the Random Related Video Views dataset are available at https://www.github.com/danielgordon10/vince




90

Trees and Forests in Nuclear Physics. (arXiv:2002.10290v2 [nucl-th] UPDATED)

We present a simple introduction to the decision tree algorithm using some examples from nuclear physics. We show how to improve the accuracy of the classical liquid drop nuclear mass model by performing Feature Engineering with a decision tree. Finally, we apply the method to the Duflo-Zuker model showing that, despite their simplicity, decision trees are capable of improving the description of nuclear masses using a limited number of free parameters.




90

Imitation Learning for Human-robot Cooperation Using Bilateral Control. (arXiv:1909.13018v2 [cs.RO] UPDATED)

Robots are required to operate autonomously in response to changing situations. Previously, imitation learning using 4ch-bilateral control was demonstrated to be suitable for imitation of object manipulation. However, cooperative work between humans and robots has not yet been verified in these studies. In this study, the task was expanded by cooperative work between a human and a robot. 4ch-bilateral control was used to collect training data for training robot motion. We focused on serving salad as a task in the home. The task was executed with a spoon and a fork fixed to robots. Adjustment of force was indispensable in manipulating indefinitely shaped objects such as salad. Results confirmed the effectiveness of the proposed method as demonstrated by the success of the task.




90

Box Covers and Domain Orderings for Beyond Worst-Case Join Processing. (arXiv:1909.12102v2 [cs.DB] UPDATED)

Recent beyond worst-case optimal join algorithms Minesweeper and its generalization Tetris have brought the theory of indexing and join processing together by developing a geometric framework for joins. These algorithms take as input an index $mathcal{B}$, referred to as a box cover, that stores output gaps that can be inferred from traditional indexes, such as B+ trees or tries, on the input relations. The performances of these algorithms highly depend on the certificate of $mathcal{B}$, which is the smallest subset of gaps in $mathcal{B}$ whose union covers all of the gaps in the output space of a query $Q$. We study how to generate box covers that contain small size certificates to guarantee efficient runtimes for these algorithms. First, given a query $Q$ over a set of relations of size $N$ and a fixed set of domain orderings for the attributes, we give a $ ilde{O}(N)$-time algorithm called GAMB which generates a box cover for $Q$ that is guaranteed to contain the smallest size certificate across any box cover for $Q$. Second, we show that finding a domain ordering to minimize the box cover size and certificate is NP-hard through a reduction from the 2 consecutive block minimization problem on boolean matrices. Our third contribution is a $ ilde{O}(N)$-time approximation algorithm called ADORA to compute domain orderings, under which one can compute a box cover of size $ ilde{O}(K^r)$, where $K$ is the minimum box cover for $Q$ under any domain ordering and $r$ is the maximum arity of any relation. This guarantees certificates of size $ ilde{O}(K^r)$. We combine ADORA and GAMB with Tetris to form a new algorithm we call TetrisReordered, which provides several new beyond worst-case bounds. On infinite families of queries, TetrisReordered's runtimes are unboundedly better than the bounds stated in prior work.




90

Global Locality in Biomedical Relation and Event Extraction. (arXiv:1909.04822v2 [cs.CL] UPDATED)

Due to the exponential growth of biomedical literature, event and relation extraction are important tasks in biomedical text mining. Most work only focus on relation extraction, and detect a single entity pair mention on a short span of text, which is not ideal due to long sentences that appear in biomedical contexts. We propose an approach to both relation and event extraction, for simultaneously predicting relationships between all mention pairs in a text. We also perform an empirical study to discuss different network setups for this purpose. The best performing model includes a set of multi-head attentions and convolutions, an adaptation of the transformer architecture, which offers self-attention the ability to strengthen dependencies among related elements, and models the interaction between features extracted by multiple attention heads. Experiment results demonstrate that our approach outperforms the state of the art on a set of benchmark biomedical corpora including BioNLP 2009, 2011, 2013 and BioCreative 2017 shared tasks.




90

The Mapillary Traffic Sign Dataset for Detection and Classification on a Global Scale. (arXiv:1909.04422v2 [cs.CV] UPDATED)

Traffic signs are essential map features globally in the era of autonomous driving and smart cities. To develop accurate and robust algorithms for traffic sign detection and classification, a large-scale and diverse benchmark dataset is required. In this paper, we introduce a traffic sign benchmark dataset of 100K street-level images around the world that encapsulates diverse scenes, wide coverage of geographical locations, and varying weather and lighting conditions and covers more than 300 manually annotated traffic sign classes. The dataset includes 52K images that are fully annotated and 48K images that are partially annotated. This is the largest and the most diverse traffic sign dataset consisting of images from all over world with fine-grained annotations of traffic sign classes. We have run extensive experiments to establish strong baselines for both the detection and the classification tasks. In addition, we have verified that the diversity of this dataset enables effective transfer learning for existing large-scale benchmark datasets on traffic sign detection and classification. The dataset is freely available for academic research: https://www.mapillary.com/dataset/trafficsign.




90

Over-the-Air Computation Systems: Optimization, Analysis and Scaling Laws. (arXiv:1909.00329v2 [cs.IT] UPDATED)

For future Internet of Things (IoT)-based Big Data applications (e.g., smart cities/transportation), wireless data collection from ubiquitous massive smart sensors with limited spectrum bandwidth is very challenging. On the other hand, to interpret the meaning behind the collected data, it is also challenging for edge fusion centers running computing tasks over large data sets with limited computation capacity. To tackle these challenges, by exploiting the superposition property of a multiple-access channel and the functional decomposition properties, the recently proposed technique, over-the-air computation (AirComp), enables an effective joint data collection and computation from concurrent sensor transmissions. In this paper, we focus on a single-antenna AirComp system consisting of $K$ sensors and one receiver (i.e., the fusion center). We consider an optimization problem to minimize the computation mean-squared error (MSE) of the $K$ sensors' signals at the receiver by optimizing the transmitting-receiving (Tx-Rx) policy, under the peak power constraint of each sensor. Although the problem is not convex, we derive the computation-optimal policy in closed form. Also, we comprehensively investigate the ergodic performance of AirComp systems in terms of the average computation MSE and the average power consumption under Rayleigh fading channels with different Tx-Rx policies. For the computation-optimal policy, we prove that its average computation MSE has a decay rate of $O(1/sqrt{K})$, and our numerical results illustrate that the policy also has a vanishing average power consumption with the increasing $K$, which jointly show the computation effectiveness and the energy efficiency of the policy with a large number of sensors.




90

Numerical study on the effect of geometric approximation error in the numerical solution of PDEs using a high-order curvilinear mesh. (arXiv:1908.09917v2 [math.NA] UPDATED)

When time-dependent partial differential equations (PDEs) are solved numerically in a domain with curved boundary or on a curved surface, mesh error and geometric approximation error caused by the inaccurate location of vertices and other interior grid points, respectively, could be the main source of the inaccuracy and instability of the numerical solutions of PDEs. The role of these geometric errors in deteriorating the stability and particularly the conservation properties are largely unknown, which seems to necessitate very fine meshes especially to remove geometric approximation error. This paper aims to investigate the effect of geometric approximation error by using a high-order mesh with negligible geometric approximation error, even for high order polynomial of order p. To achieve this goal, the high-order mesh generator from CAD geometry called NekMesh is adapted for surface mesh generation in comparison to traditional meshes with non-negligible geometric approximation error. Two types of numerical tests are considered. Firstly, the accuracy of differential operators is compared for various p on a curved element of the sphere. Secondly, by applying the method of moving frames, four different time-dependent PDEs on the sphere are numerically solved to investigate the impact of geometric approximation error on the accuracy and conservation properties of high-order numerical schemes for PDEs on the sphere.




90

A Shift Selection Strategy for Parallel Shift-Invert Spectrum Slicing in Symmetric Self-Consistent Eigenvalue Computation. (arXiv:1908.06043v2 [math.NA] UPDATED)

The central importance of large scale eigenvalue problems in scientific computation necessitates the development of massively parallel algorithms for their solution. Recent advances in dense numerical linear algebra have enabled the routine treatment of eigenvalue problems with dimensions on the order of hundreds of thousands on the world's largest supercomputers. In cases where dense treatments are not feasible, Krylov subspace methods offer an attractive alternative due to the fact that they do not require storage of the problem matrices. However, demonstration of scalability of either of these classes of eigenvalue algorithms on computing architectures capable of expressing massive parallelism is non-trivial due to communication requirements and serial bottlenecks, respectively. In this work, we introduce the SISLICE method: a parallel shift-invert algorithm for the solution of the symmetric self-consistent field (SCF) eigenvalue problem. The SISLICE method drastically reduces the communication requirement of current parallel shift-invert eigenvalue algorithms through various shift selection and migration techniques based on density of states estimation and k-means clustering, respectively. This work demonstrates the robustness and parallel performance of the SISLICE method on a representative set of SCF eigenvalue problems and outlines research directions which will be explored in future work.




90

Single use register automata for data words. (arXiv:1907.10504v2 [cs.FL] UPDATED)

Our starting point are register automata for data words, in the style of Kaminski and Francez. We study the effects of the single-use restriction, which says that a register is emptied immediately after being used. We show that under the single-use restriction, the theory of automata for data words becomes much more robust. The main results are: (a) five different machine models are equivalent as language acceptors, including one-way and two-way single-use register automata; (b) one can recover some of the algebraic theory of languages over finite alphabets, including a version of the Krohn-Rhodes Theorem; (c) there is also a robust theory of transducers, with four equivalent models, including two-way single use transducers and a variant of streaming string transducers for data words. These results are in contrast with automata for data words without the single-use restriction, where essentially all models are pairwise non-equivalent.




90

Dynamic Face Video Segmentation via Reinforcement Learning. (arXiv:1907.01296v3 [cs.CV] UPDATED)

For real-time semantic video segmentation, most recent works utilised a dynamic framework with a key scheduler to make online key/non-key decisions. Some works used a fixed key scheduling policy, while others proposed adaptive key scheduling methods based on heuristic strategies, both of which may lead to suboptimal global performance. To overcome this limitation, we model the online key decision process in dynamic video segmentation as a deep reinforcement learning problem and learn an efficient and effective scheduling policy from expert information about decision history and from the process of maximising global return. Moreover, we study the application of dynamic video segmentation on face videos, a field that has not been investigated before. By evaluating on the 300VW dataset, we show that the performance of our reinforcement key scheduler outperforms that of various baselines in terms of both effective key selections and running speed. Further results on the Cityscapes dataset demonstrate that our proposed method can also generalise to other scenarios. To the best of our knowledge, this is the first work to use reinforcement learning for online key-frame decision in dynamic video segmentation, and also the first work on its application on face videos.




90

Space-Efficient Vertex Separators for Treewidth. (arXiv:1907.00676v3 [cs.DS] UPDATED)

For $n$-vertex graphs with treewidth $k = O(n^{1/2-epsilon})$ and an arbitrary $epsilon>0$, we present a word-RAM algorithm to compute vertex separators using only $O(n)$ bits of working memory. As an application of our algorithm, we give an $O(1)$-approximation algorithm for tree decomposition. Our algorithm computes a tree decomposition in $c^k n (log log n) log^* n$ time using $O(n)$ bits for some constant $c > 0$.

We finally use the tree decomposition obtained by our algorithm to solve Vertex Cover, Independent Set, Dominating Set, MaxCut and $3$-Coloring by using $O(n)$ bits as long as the treewidth of the graph is smaller than $c' log n$ for some problem dependent constant $0 < c' < 1$.




90

Establishing the Quantum Supremacy Frontier with a 281 Pflop/s Simulation. (arXiv:1905.00444v2 [quant-ph] UPDATED)

Noisy Intermediate-Scale Quantum (NISQ) computers are entering an era in which they can perform computational tasks beyond the capabilities of the most powerful classical computers, thereby achieving "Quantum Supremacy", a major milestone in quantum computing. NISQ Supremacy requires comparison with a state-of-the-art classical simulator. We report HPC simulations of hard random quantum circuits (RQC), which have been recently used as a benchmark for the first experimental demonstration of Quantum Supremacy, sustaining an average performance of 281 Pflop/s (true single precision) on Summit, currently the fastest supercomputer in the World. These simulations were carried out using qFlex, a tensor-network-based classical high-performance simulator of RQCs. Our results show an advantage of many orders of magnitude in energy consumption of NISQ devices over classical supercomputers. In addition, we propose a standard benchmark for NISQ computers based on qFlex.




90

Parameterised Counting in Logspace. (arXiv:1904.12156v3 [cs.LO] UPDATED)

Stockhusen and Tantau (IPEC 2013) defined the operators paraW and paraBeta for parameterised space complexity classes by allowing bounded nondeterminism with multiple read and read-once access, respectively. Using these operators, they obtained characterisations for the complexity of many parameterisations of natural problems on graphs.

In this article, we study the counting versions of such operators and introduce variants based on tail-nondeterminism, paraW[1] and paraBetaTail, in the setting of parameterised logarithmic space. We examine closure properties of the new classes under the central reductions and arithmetic operations. We also identify a wide range of natural complete problems for our classes in the areas of walk counting in digraphs, first-order model-checking and graph-homomorphisms. In doing so, we also see that the closure of #paraBetaTail-L under parameterised logspace parsimonious reductions coincides with #paraBeta-L. We show that the complexity of a parameterised variant of the determinant function is #paraBetaTail-L-hard and can be written as the difference of two functions in #paraBetaTail-L for (0,1)-matrices. Finally, we characterise the new complexity classes in terms of branching programs.




90

On analog quantum algorithms for the mixing of Markov chains. (arXiv:1904.11895v2 [quant-ph] UPDATED)

The problem of sampling from the stationary distribution of a Markov chain finds widespread applications in a variety of fields. The time required for a Markov chain to converge to its stationary distribution is known as the classical mixing time. In this article, we deal with analog quantum algorithms for mixing. First, we provide an analog quantum algorithm that given a Markov chain, allows us to sample from its stationary distribution in a time that scales as the sum of the square root of the classical mixing time and the square root of the classical hitting time. Our algorithm makes use of the framework of interpolated quantum walks and relies on Hamiltonian evolution in conjunction with von Neumann measurements.

There also exists a different notion for quantum mixing: the problem of sampling from the limiting distribution of quantum walks, defined in a time-averaged sense. In this scenario, the quantum mixing time is defined as the time required to sample from a distribution that is close to this limiting distribution. Recently we provided an upper bound on the quantum mixing time for Erd"os-Renyi random graphs [Phys. Rev. Lett. 124, 050501 (2020)]. Here, we also extend and expand upon our findings therein. Namely, we provide an intuitive understanding of the state-of-the-art random matrix theory tools used to derive our results. In particular, for our analysis we require information about macroscopic, mesoscopic and microscopic statistics of eigenvalues of random matrices which we highlight here. Furthermore, we provide numerical simulations that corroborate our analytical findings and extend this notion of mixing from simple graphs to any ergodic, reversible, Markov chain.




90

A Fast and Accurate Algorithm for Spherical Harmonic Analysis on HEALPix Grids with Applications to the Cosmic Microwave Background Radiation. (arXiv:1904.10514v4 [math.NA] UPDATED)

The Hierarchical Equal Area isoLatitude Pixelation (HEALPix) scheme is used extensively in astrophysics for data collection and analysis on the sphere. The scheme was originally designed for studying the Cosmic Microwave Background (CMB) radiation, which represents the first light to travel during the early stages of the universe's development and gives the strongest evidence for the Big Bang theory to date. Refined analysis of the CMB angular power spectrum can lead to revolutionary developments in understanding the nature of dark matter and dark energy. In this paper, we present a new method for performing spherical harmonic analysis for HEALPix data, which is a central component to computing and analyzing the angular power spectrum of the massive CMB data sets. The method uses a novel combination of a non-uniform fast Fourier transform, the double Fourier sphere method, and Slevinsky's fast spherical harmonic transform (Slevinsky, 2019). For a HEALPix grid with $N$ pixels (points), the computational complexity of the method is $mathcal{O}(Nlog^2 N)$, with an initial set-up cost of $mathcal{O}(N^{3/2}log N)$. This compares favorably with $mathcal{O}(N^{3/2})$ runtime complexity of the current methods available in the HEALPix software when multiple maps need to be analyzed at the same time. Using numerical experiments, we demonstrate that the new method also appears to provide better accuracy over the entire angular power spectrum of synthetic data when compared to the current methods, with a convergence rate at least two times higher.




90

Constrained Restless Bandits for Dynamic Scheduling in Cyber-Physical Systems. (arXiv:1904.08962v3 [cs.SY] UPDATED)

Restless multi-armed bandits are a class of discrete-time stochastic control problems which involve sequential decision making with a finite set of actions (set of arms). This paper studies a class of constrained restless multi-armed bandits (CRMAB). The constraints are in the form of time varying set of actions (set of available arms). This variation can be either stochastic or semi-deterministic. Given a set of arms, a fixed number of them can be chosen to be played in each decision interval. The play of each arm yields a state dependent reward. The current states of arms are partially observable through binary feedback signals from arms that are played. The current availability of arms is fully observable. The objective is to maximize long term cumulative reward. The uncertainty about future availability of arms along with partial state information makes this objective challenging. Applications for CRMAB abound in the domain of cyber-physical systems. This optimization problem is analyzed using Whittle's index policy. To this end, a constrained restless single-armed bandit is studied. It is shown to admit a threshold-type optimal policy, and is also indexable. An algorithm to compute Whittle's index is presented. Further, upper bounds on the value function are derived in order to estimate the degree of sub-optimality of various solutions. The simulation study compares the performance of Whittle's index, modified Whittle's index and myopic policies.




90

Fast Cross-validation in Harmonic Approximation. (arXiv:1903.10206v3 [math.NA] UPDATED)

Finding a good regularization parameter for Tikhonov regularization problems is a though yet often asked question. One approach is to use leave-one-out cross-validation scores to indicate the goodness of fit. This utilizes only the noisy function values but, on the downside, comes with a high computational cost. In this paper we present a general approach to shift the main computations from the function in question to the node distribution and, making use of FFT and FFT-like algorithms, even reduce this cost tremendously to the cost of the Tikhonov regularization problem itself. We apply this technique in different settings on the torus, the unit interval, and the two-dimensional sphere. Given that the sampling points satisfy a quadrature rule our algorithm computes the cross-validations scores in floating-point precision. In the cases of arbitrarily scattered nodes we propose an approximating algorithm with the same complexity. Numerical experiments indicate the applicability of our algorithms.




90

Ranked List Loss for Deep Metric Learning. (arXiv:1903.03238v6 [cs.CV] UPDATED)

The objective of deep metric learning (DML) is to learn embeddings that can capture semantic similarity and dissimilarity information among data points. Existing pairwise or tripletwise loss functions used in DML are known to suffer from slow convergence due to a large proportion of trivial pairs or triplets as the model improves. To improve this, ranking-motivated structured losses are proposed recently to incorporate multiple examples and exploit the structured information among them. They converge faster and achieve state-of-the-art performance. In this work, we unveil two limitations of existing ranking-motivated structured losses and propose a novel ranked list loss to solve both of them. First, given a query, only a fraction of data points is incorporated to build the similarity structure. To address this, we propose to build a set-based similarity structure by exploiting all instances in the gallery. The learning setting can be interpreted as few-shot retrieval: given a mini-batch, every example is iteratively used as a query, and the rest ones compose the galley to search, i.e., the support set in few-shot setting. The rest examples are split into a positive set and a negative set. For every mini-batch, the learning objective of ranked list loss is to make the query closer to the positive set than to the negative set by a margin. Second, previous methods aim to pull positive pairs as close as possible in the embedding space. As a result, the intraclass data distribution tends to be extremely compressed. In contrast, we propose to learn a hypersphere for each class in order to preserve useful similarity structure inside it, which functions as regularisation. Extensive experiments demonstrate the superiority of our proposal by comparing with the state-of-the-art methods on the fine-grained image retrieval task.




90

Keeping out the Masses: Understanding the Popularity and Implications of Internet Paywalls. (arXiv:1903.01406v4 [cs.CY] UPDATED)

Funding the production of quality online content is a pressing problem for content producers. The most common funding method, online advertising, is rife with well-known performance and privacy harms, and an intractable subject-agent conflict: many users do not want to see advertisements, depriving the site of needed funding.

Because of these negative aspects of advertisement-based funding, paywalls are an increasingly popular alternative for websites. This shift to a "pay-for-access" web is one that has potentially huge implications for the web and society. Instead of a system where information (nominally) flows freely, paywalls create a web where high quality information is available to fewer and fewer people, leaving the rest of the web users with less information, that might be also less accurate and of lower quality. Despite the potential significance of a move from an "advertising-but-open" web to a "paywalled" web, we find this issue understudied.

This work addresses this gap in our understanding by measuring how widely paywalls have been adopted, what kinds of sites use paywalls, and the distribution of policies enforced by paywalls. A partial list of our findings include that (i) paywall use is accelerating (2x more paywalls every 6 months), (ii) paywall adoption differs by country (e.g. 18.75% in US, 12.69% in Australia), (iii) paywalls change how users interact with sites (e.g. higher bounce rates, less incoming links), (iv) the median cost of an annual paywall access is $108 per site, and (v) paywalls are in general trivial to circumvent.

Finally, we present the design of a novel, automated system for detecting whether a site uses a paywall, through the combination of runtime browser instrumentation and repeated programmatic interactions with the site. We intend this classifier to augment future, longitudinal measurements of paywall use and behavior.




90

Deterministic Sparse Fourier Transform with an ell_infty Guarantee. (arXiv:1903.00995v3 [cs.DS] UPDATED)

In this paper we revisit the deterministic version of the Sparse Fourier Transform problem, which asks to read only a few entries of $x in mathbb{C}^n$ and design a recovery algorithm such that the output of the algorithm approximates $hat x$, the Discrete Fourier Transform (DFT) of $x$. The randomized case has been well-understood, while the main work in the deterministic case is that of Merhi et al.@ (J Fourier Anal Appl 2018), which obtains $O(k^2 log^{-1}k cdot log^{5.5}n)$ samples and a similar runtime with the $ell_2/ell_1$ guarantee. We focus on the stronger $ell_{infty}/ell_1$ guarantee and the closely related problem of incoherent matrices. We list our contributions as follows.

1. We find a deterministic collection of $O(k^2 log n)$ samples for the $ell_infty/ell_1$ recovery in time $O(nk log^2 n)$, and a deterministic collection of $O(k^2 log^2 n)$ samples for the $ell_infty/ell_1$ sparse recovery in time $O(k^2 log^3n)$.

2. We give new deterministic constructions of incoherent matrices that are row-sampled submatrices of the DFT matrix, via a derandomization of Bernstein's inequality and bounds on exponential sums considered in analytic number theory. Our first construction matches a previous randomized construction of Nelson, Nguyen and Woodruff (RANDOM'12), where there was no constraint on the form of the incoherent matrix.

Our algorithms are nearly sample-optimal, since a lower bound of $Omega(k^2 + k log n)$ is known, even for the case where the sensing matrix can be arbitrarily designed. A similar lower bound of $Omega(k^2 log n/ log k)$ is known for incoherent matrices.




90

Asymptotic expansions of eigenvalues by both the Crouzeix-Raviart and enriched Crouzeix-Raviart elements. (arXiv:1902.09524v2 [math.NA] UPDATED)

Asymptotic expansions are derived for eigenvalues produced by both the Crouzeix-Raviart element and the enriched Crouzeix--Raviart element. The expansions are optimal in the sense that extrapolation eigenvalues based on them admit a fourth order convergence provided that exact eigenfunctions are smooth enough. The major challenge in establishing the expansions comes from the fact that the canonical interpolation of both nonconforming elements lacks a crucial superclose property, and the nonconformity of both elements. The main idea is to employ the relation between the lowest-order mixed Raviart--Thomas element and the two nonconforming elements, and consequently make use of the superclose property of the canonical interpolation of the lowest-order mixed Raviart--Thomas element. To overcome the difficulty caused by the nonconformity, the commuting property of the canonical interpolation operators of both nonconforming elements is further used, which turns the consistency error problem into an interpolation error problem. Then, a series of new results are obtained to show the final expansions.




90

Machine learning topological phases in real space. (arXiv:1901.01963v4 [cond-mat.mes-hall] UPDATED)

We develop a supervised machine learning algorithm that is able to learn topological phases for finite condensed matter systems from bulk data in real lattice space. The algorithm employs diagonalization in real space together with any supervised learning algorithm to learn topological phases through an eigenvector ensembling procedure. We combine our algorithm with decision trees and random forests to successfully recover topological phase diagrams of Su-Schrieffer-Heeger (SSH) models from bulk lattice data in real space and show how the Shannon information entropy of ensembles of lattice eigenvectors can be used to retrieve a signal detailing how topological information is distributed in the bulk. The discovery of Shannon information entropy signals associated with topological phase transitions from the analysis of data from several thousand SSH systems illustrates how model explainability in machine learning can advance the research of exotic quantum materials with properties that may power future technological applications such as qubit engineering for quantum computing.




90

VM placement over WDM-TDM AWGR PON Based Data Centre Architecture. (arXiv:2005.03590v1 [cs.NI])

Passive optical networks (PON) can play a vital role in data centres and access fog solutions by providing scalable, cost and energy efficient architectures. This paper proposes a Mixed Integer Linear Programming (MILP) model to optimize the placement of virtual machines (VMs) over an energy efficient WDM-TDM AWGR PON based data centre architecture. In this optimization, the use of VMs and their requirements affect the optimum number of servers utilized in the data centre when minimizing the power consumption and enabling more efficient utilization of servers is considered. Two power consumption minimization objectives were examined for up to 20 VMs with different computing and networking requirements. The results indicate that considering the minimization of the processing and networking power consumption in the allocation of VMs in the WDM-TDM AWGR PON can reduce the networking power consumption by up to 70% compared to the minimization of the processing power consumption.




90

A Dynamical Perspective on Point Cloud Registration. (arXiv:2005.03190v1 [cs.CV])

We provide a dynamical perspective on the classical problem of 3D point cloud registration with correspondences. A point cloud is considered as a rigid body consisting of particles. The problem of registering two point clouds is formulated as a dynamical system, where the dynamic model point cloud translates and rotates in a viscous environment towards the static scene point cloud, under forces and torques induced by virtual springs placed between each pair of corresponding points. We first show that the potential energy of the system recovers the objective function of the maximum likelihood estimation. We then adopt Lyapunov analysis, particularly the invariant set theorem, to analyze the rigid body dynamics and show that the system globally asymptotically tends towards the set of equilibrium points, where the globally optimal registration solution lies in. We conjecture that, besides the globally optimal equilibrium point, the system has either three or infinite "spurious" equilibrium points, and these spurious equilibria are all locally unstable. The case of three spurious equilibria corresponds to generic shape of the point cloud, while the case of infinite spurious equilibria happens when the point cloud exhibits symmetry. Therefore, simulating the dynamics with random perturbations guarantees to obtain the globally optimal registration solution. Numerical experiments support our analysis and conjecture.




90

A Multifactorial Optimization Paradigm for Linkage Tree Genetic Algorithm. (arXiv:2005.03090v1 [cs.NE])

Linkage Tree Genetic Algorithm (LTGA) is an effective Evolutionary Algorithm (EA) to solve complex problems using the linkage information between problem variables. LTGA performs well in various kinds of single-task optimization and yields promising results in comparison with the canonical genetic algorithm. However, LTGA is an unsuitable method for dealing with multi-task optimization problems. On the other hand, Multifactorial Optimization (MFO) can simultaneously solve independent optimization problems, which are encoded in a unified representation to take advantage of the process of knowledge transfer. In this paper, we introduce Multifactorial Linkage Tree Genetic Algorithm (MF-LTGA) by combining the main features of both LTGA and MFO. MF-LTGA is able to tackle multiple optimization tasks at the same time, each task learns the dependency between problem variables from the shared representation. This knowledge serves to determine the high-quality partial solutions for supporting other tasks in exploring the search space. Moreover, MF-LTGA speeds up convergence because of knowledge transfer of relevant problems. We demonstrate the effectiveness of the proposed algorithm on two benchmark problems: Clustered Shortest-Path Tree Problem and Deceptive Trap Function. In comparison to LTGA and existing methods, MF-LTGA outperforms in quality of the solution or in computation time.




90

Compounds that inhibit Hsp90 protein-protein interactions with IAP proteins

Disclosed herein are compounds that inhibit Hsp90 interactions with IAP proteins, such as Survivin, XIAP, cIAP1, or cIAP2, and methods for identifying and using such compounds.




90

Method for processing explosives containing 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazatetracyclo[5.5.0.05,903,11]-dodecane (CL-20) with naphthenic and paraffinic oils

A method for processing explosives containing a high loading of CL-20 may advantageously include a binder system having naphthenic oil and/or paraffinic oil. Solid energetic ingredients are added into the binder system and mixed to form a free-flowing suspension in which the solid energetic ingredients are homogeneously mixed and coated with the binder system. The binder system is then cured and cast to form a cross-linked explosive.




90

King's Somborne dog show in 1990

OWNERS put almost as much effort into the performances as their pets for the Dog Ability Challenge staged at King's Somborne horse trials on April 23, 1990.




90

90: Shea Serrano

Shea Serrano is a Houston-based writer and illustrator whose funny, insightful work on rap, sports, and even action movies has appeared almost everywhere – you undoubtedly saw his brilliant holiday piece Three Wise Migos. In addition, he wrote Bun B’s Rapper Coloring and Activity Book and created the viral Tumblr sensations Drake-ing Bad and Sex Questions From Seventh Graders.

We spoke to Serrano about his life and career, why ‘94 will always be r&b’s peak year, and why he’s okay with you loving J. Cole, even if you’re wrong.

See http://theciphershow.com/episode/90/ for full show notes and comments.




90

190: Paradise Gray

Paradise Gray began his career in hip-hop under the tutelage of masters like Pete DJ Jones and Disco King Mario. However, he really hit his stride when he began booking hip-hop acts and hosting in 1986 at a nightclub in the heart of Times Square called the Latin Quarter. While at the club, he would have a front row seat to the introduction of a new generation of hip-hop artists—the key acts in what would come to be called the genre’s Golden Age.

After the club closed in 1988, Paradise would form the group X-Clan with some friends, and deliver some of the most powerful, conscious rap records of all time.

Paradise has a new book about his time at the LQ called No Half Steppin’: An Oral and Pictorial History of New York City Club the Latin Quarter and the Birth of Hip-Hop’s Golden Era.

See http://theciphershow.com/episode/190/ for full show notes and comments.




90

248: Jonah Hill and the 'Mid90s' Cast

Mid90s, which opened this past Friday, October 19th, is a film Hill wrote and directed about a group of skateboarding friends in—you guessed it—the mid-1990s. The incredibly authentic period piece features plenty of nods to the skateboarding scene and the music of the time period, including songs from the Pharcyde and the Gravediggaz, and a memorable cameo appearance by Del the Funkee Homosapien.

This is Jonah’s first film as a writer/director. He has, of course, starred in tons of films, from Superbad to Moneyball to The Wolf of Wall Street. For this interview, Hill was joined by Sunny Suljic, who plays Stevie; Na-kel Smith, who plays Ray; Olan Prenatt, who plays Fuckshit; Gio Galicia, who plays Ruben; Ryder McLaughlin, who plays Fourth Grade; and Alexa Demie, who plays Estee. To rap fans, Na-Kel Smith’s name and voice may sound familiar—he has a music career of his own, and has appeared on songs with Tyler, the Creator and Earl Sweatshirt.

See http://theciphershow.com/episode/248/ for full show notes and comments.




90

06/19/2013 - The Church Of What's Happening Now #90

Omar, the editor of Joey's book calls in to talk about the thought behind the book and to give a status update.


This podcast is brought to you by Onnit.com Use Promo code CHURCH for a discount at checkout.


This podcast is also brought to you by Hulu Plus. Go to huluplus.com/joey for an extended free trial.

Streamed live on 06/19/2013




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#190 - Joey Diaz, Dom Irrera and Lee Syatt

Joey Diaz and Lee Syatt are joined by Comedian Dom Irrera in studio.

This podcast is brought to you by:

Onnit.com. Use Promo code CHURCH for a discount at checkout.

Nature Box. Visit Naturebox.com and use promo code Joey for 50% off your first order.

Naileditlife.com - Get 20% off a vapor pen by mentioning the Church.

Recorded live on 06/23/2014.




90

#290 - Billy Corben

Billy Corben, director of the new documentary "Dawg Fight," calls in to Joey Diaz and Lee Syatt.
This podcast is brought to you by:
 
Onnit.com. Use Promo code CHURCH for a discount at checkout.
 

NatureBox. Visit Naturebox.com/joey for a free trial box.
 
Meundies.com Go to meundies.com/joey for 20% off.
 
Iron Dragon TV. A New Roku channel with all the best martial arts films. Use Code word joey for two free rentals.
 
Recorded live on 06/11/2015.

 
Music:

Mean Streets - Van Halen
Today Was A Good Day - Ice Cube
 




90

#390 - Nic Gregoriades

Nicolas Gregoriades, a South African jiu jitsu black belt under Roger Gracie and creator of jiujitsubrotherhood.com, joins Joey Diaz and Lee Syatt live in studio.

This podcast is brought to you by:
 
Blue Apron: Go to blueapron.com/JOEY to get your first three meals free and free shipping!
 
Datsusara: Go to DSgear.com and check out all of their great products, like gi's and rash guards, that are made with high quality hemp textiles. Use code Joey to get 5% off of your order.
  
Onnit.com. Use Promo code CHURCH for a discount at checkout.
 
Recorded live on 06/19/2016




90

#490 - Bill Herenda

Bill Herenda, an NBA and College Basketball analyst as well as the morning sports anchor for KFBK in Sacramento, joins Joey Diaz and Lee Syatt LIVE in studio.

This podcast is brought to you by: 

Meundies.com Go to meundies.com/JOEY for 20% off of your first order.

Hellotushy.com - Go to Hellotushy.com/church for 10% off of your order of portable devices that spray your butt with water.

 
Onnit.com. Use Promo code CHURCH for a discount at checkout.
 
Recorded live on 06/14/2017.





90

#590 - Joey Diaz and Lee Syatt: Hours before Joey shoots his Netflix special

Joey Diaz talks with Lee Syatt about what it's like for him to be so close to shooting his special for Netflix. They talk about his comedy career, how his preparation has changed over the years, and why he is ready for this day.

This podcast is brought to you by:

ZipRecruiter - post your job to 200+ job sites with a single click for free at www.ziprecruiter.com/church
 
Onnit.com - Use Promo code CHURCH for a 10% discount at checkout.
 
 




90

#690 - Pablo Francisco

Pablo Francisco, a stand up comedian with many specials and appearances on MADtv and The Tonight Show, joins Joey Diaz and Lee Syatt LIVE in studio.

This podcast is brought to you by:
 
23andme.com - 23andMe is a DNA testing service that can offer you insights on to how your DNA can influence your weight, sleep quality and much more. Order your 23andMe health and ancestry kit at 23andMe.com/church. For a limited time only, get $50 off of your kit for Father's Day Day. Deal expires on June 17, 2019.
 
Hellotushy.com - Go to Hellotushy.com/church for 10% off of your portable bidet.
 




90

Save 90% on Ugritone’s Assault Drums & Koji virtual instruments

Ugritone has launched a weekend sale on two of its virtual instruments. Assault Drums is a virtual drum instrument with the sound of 80s/90s Heavy Metal/Rock. Multiple routing options and advanced humanizing scripts give each and every drum a natural feel so you can dial tones from Assault Drums as if you were processing real […]

The post Save 90% on Ugritone’s Assault Drums & Koji virtual instruments appeared first on rekkerd.org.




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Save 90% on Exponential Audio’s PhoenixVerb Stereo, on sale for $9.99 USD!

Plugin Boutique has launched an exclusive sale on PhoenixVerb Stereo, the reverb effect plugin by Exponential Audio that brings clear, lifelike dimension to your mixes. Create natural, authentic depth for your music by crafting spaces from scratch or using one of over 900 presets included in PhoenixVerb, including room, plate, hall, chamber, and more. The […]

The post Save 90% on Exponential Audio’s PhoenixVerb Stereo, on sale for $9.99 USD! appeared first on rekkerd.org.




90

Coronavirus : Apple reopens 90 per cent of retail stores in China

Apple reopened 38 Apple stores which were temporarily closed after the epidemic, state-run China Daily reported. Only four stores remain closed.




90

Northern Michigan photographer dupes fudgies in early 1900s

Edward Beebe was a popular photographer in northern Michigan in the early 1900s. He created postcards with his photos but often deceived people regarding the location of the shots. “I think a lot of these cards were intended to take advantage of tourists and visitors,” says local author Jack Hobey.




90

More Than 90% of Self-Isolating Families Have at Least One OTT Service

New survey data from Hub Entertainment Research reveals the impact of COVID-19 on OTT services and pay TV




90

Rose McGowan accuses Bill Maher of whispering crude comment to her about his body in the 1990s

Actress and #MeToo leader Rose McGowan has accused comedian Bill Maher of whispering a crude comment about his body when she appeared on his show "Politically Incorrect" in the late 1990s.




90

cover of Freedom '90 by George Michael by nayantara

I've been working on a musical collaboration with a fellow musician friend of mine during these crazy coronavirus times, in hopes of generating something fun and creative while we have all this spare time not working or gigging. Here's the second song from that collaboration.