## 信息流

• This communications chip helped to usher in the age of broadband Internet

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• India is pressing Microsoft to offer a sharply discounted one-time deal to the more than 50 million Windows users in the country so that they can upgrade to the latest Windows 10 operating system in the wake of ransomware attacks, Reuters reported Friday. From the article: Microsoft officials in India have "in principle agreed" to the request, Gulshan Rai, India's cyber security coordinator, told Reuters over the phone on Friday. If Microsoft agreed to such a discount, it could open up the global software giant to similar requests from around the world. Rai said the government was in talks with Microsoft management in India. It is not immediately clear whether any other countries were seeking similar deals.

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• Japan plans to put a man on the moon around 2030, according to a new proposal by the government's Japan Aerospace Exploration Agency (JAXA). From a report: It is the first time JAXA has revealed an intention to send Japanese astronauts beyond the International Space Station, and it will mostly likely be part of an international mission, the agency said. The announcement from Japan is just the latest in a series of ambitious space exploration plans by Asian countries, with the increasing competition for space-related power and prestige in the region echoing that of the Cold War space race of the mid-20th century. In December 2016, China announced plans to land a rover on Mars by 2020 as well as a manned mission to the Moon at some point in the future.

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•   07-01 Hacker News 100

Mattermark Is Hiring a Data Analyst Intern

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• McClure steps back at 500Startups after internal sexual misconduct investigation

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•   07-01 THE NEW YORKER 93

Inside Donald Trump’s gilded Palm Beach palace, and the journalist Jon Ronson tries his hand at fiction, in “Okja.”

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•   07-01 Hacker News 96

NYPD is canceling its Palantir contract

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•   07-01 Ars Technica 91

Event was highly anticipated, as it signaled the deeper involvement of Mike Pence.

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•   07-01 Hacker News 97

Poverty is not a personal choice, but a reflection of society

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•   07-01 IEEE 92

Mouser and Grant Imahara team up with the creative minds at WIRED Brand Lab to take a look at the modern city

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•   07-01 Hacker News 92

Show HN: Visualizing 'Silhouettes' of Programming Languages

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•   07-01 Hacker News 94

How a 20-year-old kernel feature helped USDS improve VA’s network

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•   07-01 Ars Technica 90

Installation 01 can continue to operate as long as it stays non-commercial.

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•   07-01 IEEE 91

Hardware that can transform itself on command has proven incredibly useful

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•   07-01 IEEE 87

Another legend from the 8-bit era, this processor powered the first portable computer as well as the beloved “Trash-80”

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•   07-01 Hacker News 95

Chris Lattner on the Realm WWDC 2017 Swift Panel

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•   07-01 Ars Technica 90

Plus some Amazon Prime-exclusive deals before Prime Day even hits.

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• The U.S. tech sector pushed the government to keep ties with Russia's spy agency, despite reports that Moscow meddled in the U.S. presidential election, Reuters reported Friday. The sanctions imposed on Russia by the Obama administration last December outlawed U.S. companies from having relationships with Russia's spy agency, the Federal Security Service (FSB), which presented a dilemma to Western tech companies. Reuters says, the FSB also acts as a regulator that approves the importing of technology to Russia that contains encryption, which is used in products such as cellphones and laptops. Joel Schectman, Dustin Volz and Jack Stubbs, reporting for Reuters: Worried about the sales impact, business industry groups, including the U.S.-Russia Business Council and the American Chamber of Commerce in Russia, contacted U.S. officials at the American embassy in Moscow and the Treasury, State and Commerce departments, according to five people with direct knowledge of the lobbying effort. The

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•   07-01 Hacker News 98

Do 20 pages of a book gives you 90% of its words?

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•   07-01 Ars Technica 94

Agency head reported to desire “back-and-forth critique” of published research.

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•   07-01 Hacker News 102

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•   07-01 Slashdot 94

Analyst Ben Thompson on the European Commission's $2.7 billion fine levied on Google for anti-competitive behavior: The United States and European Union have, at least since the Reagan Administration, differed on this point: the U.S. is primarily concerned with consumer welfare, and the primary proxy is price. In other words, as long as prices do not increase -- or even better, decrease -- there is, by definition, no illegal behavior. The European Commission, on the other hand, is explicitly focused on competition: monopolistic behavior is presumed to be illegal if it restricts competitors which, in the theoretical long run, hurts consumers by restricting innovation. 收起 • Facebook has completed a second test of a solar-powered drone -- called Aquila -- designed to bring internet access to remote parts of the world. From a report: Facebook plans to develop a fleet of drones powered by sunlight that will fly for months at a time, communicating with each other through lasers and extending internet connectivity to the ground below. The company called the first test, in June 2016, a success after it flew above the Arizona desert for 1 hour and 36 minutes, three times longer than planned. It later said the drone had also crashed moments before landing and had suffered a damaged wing. 收起 • 07-01 THE NEW YORKER 106 Carrie Battan reviews the new Jay-Z album, “4:44,” and considers how it reflects his views on fatherhood and middle age. 收起 • Reader Mark Wilson writes: There have been lots of complaints about invasion of privacy since the release of Windows 10. Microsoft's telemetry lead to several lawsuits, including one from France's National Data Protection Commission which said Windows 10 was collecting 'excessive personal data' about users. But now the Commission Nationale de l'Informatique et des Libert's has decided to drop its case against Microsoft. The commission is happy that sufficient steps have been taken to reduce the amount of data that is collected and users are now informed about data collection. 收起 • 07-01 Ars Technica 98 German legislators want hate speech removed within 24 hours. 收起 • 07-01 Hacker News 105 Silicon Valley Women, in Cultural Shift, Frankly Describe Sexual Harassment 收起 • 07-01 Hacker News 83 What is a file? (2011) 收起 • 07-01 Hacker News 67 Apple and LaTeX 收起 • Given a compact Riemann surface$X$and a complex reductive Lie group$G$equipped with real structures, we define antiholomorphic involutions on the moduli space of$G$-Higgs bundles over$X$. We investigate how the various components of the fixed point locus match up, as one passes from$G$to its Langlands dual$^LG$. Special attention is given to the case$G=SL(2,\C)$and$^LG=PGL(2,\C)$. 收起 • In this paper, we extend the geometric concept of linearity to betweenness structures, suitable combinatorial abstractions of finite metric spaces. As our main result, we prove that every linear betweenness structure is induced by either a path (of length$n$) or a cycle of length 4. 收起 • We study chirally cosmetic surgeries, that is, a pair of Dehn surgeries on a knot producing homeomorphic 3-manifolds with opposite orientations. Several constraints on knots and surgery slopes to admit such surgeries are given. Our main ingredients are the original and the$SL(2,\mathbb{C})$version of Casson invariants. As applications, we discuss non-existence for chirally cosmetic surgeries on almost positive knots, and we give a complete classification of chirally cosmetic surgeries on two bridge knots of genus one. 收起 • We show that, on a complete and possibly non-compact Riemannian manifold of dimension at least 2 without close conjugate points at infinity, the existence of a closed geodesic with local homology in maximal degree and maximal index growth under iteration forces the existence of infinitely many closed geodesics. For closed manifolds, this was a theorem due to Hingston. 收起 • The rise of machine-to-machine communications has rekindled the interest in random access protocols as a support for a massive number of uncoordinatedly transmitting devices. The legacy ALOHA approach is developed under a collision model, where slots containing collided packets are considered as waste. However, if the common receiver (e.g., base station) is capable to store the collision slots and use them in a transmission recovery process based on successive interference cancellation, the design space for access protocols is radically expanded. We present the paradigm of coded random access, in which the structure of the access protocol can be mapped to a structure of an erasure-correcting code defined on graph. This opens the possibility to use coding theory and tools for designing efficient random access protocols, offering markedly better performance than ALOHA. Several instances of coded random access protocols are described, as well as a case study on how to upgrade a legacy ALO 收起 • Every partial colouring of a Hamming graph is uniquely related to a partial Latin hyper-rectangle. In this paper we introduce the$\Theta$-stabilized$(a,b)$-colouring game for Hamming graphs, a variant of the$(a,b)$-colouring game so that each move must respect a given autotopism$\Theta$of the resulting partial Latin hyper-rectangle. We examine the complexity of this variant by means of its chromatic number. We focus in particular on the bi-dimensional case, for which the game is played on the Cartesian product of two complete graphs, and also on the hypercube case. 收起 • Given two distinct newforms with real Fourier coefficients, we show that the set of primes where the Hecke eigenvalues of one of them dominate the Hecke eigenvalues of the other has density at least 1/16. Furthermore, if the two newforms do not have complex multiplication, and neither is a quadratic twist of the other, we also prove a similar result for the squares of their Hecke eigenvalues. 收起 • The introduction of a fractional differential operator defined in terms of the Riemann-Liouville derivative makes it possible to generalize the kinetic equations used to model relaxation in dielectrics. In this context such fractional equations are called fractional kinetic relaxation equations and their solutions, called fractional kinetic relaxation functions, are given in terms of Mittag-Leffler functions. These fractional kinetic relaxation functions generalize the kinetic relaxation functions associated with the Debye, Cole-Cole, Cole-Davidson and Havriliak-Negami models, as the latter functions become particular cases of the fractional solutions, obtained for specific values of the parameter specifying the order of the derivative. The aim of this work is to analyse the behavior of these fractional functions in the time variable. As theoretical tools we use the theorem by Bernstein on the complete monotonicity of functions together with Titchmarsh's inversion formula. The last par 收起 • We construct the first non-trivial examples of complete families of non-degenerate smooth space curves, and show that the base of such a family cannot be a rational curve. Both results rely on the study of the strong semistability of certain vector bundles. 收起 • In this work, we derive upper bounds on the cardinality of tandem and palindromic duplication correcting codes by deriving the generalized sphere packing bound for these error types. We first prove that an upper bound for tandem or palindromic deletions is also an upper bound for inserting the respective type of duplications. Therefore, we derive the bounds based on these special deletions as this results in tighter bounds. We determine the spheres for tandem and palindromic duplications/deletions and the number of words with a specific sphere size. Our upper bounds on the cardinality directly imply lower bounds on the redundancy which we compare with the redundancy of the best known construction correcting arbitrary burst errors. Our results indicate that the correction of palindromic duplications requires more redundancy than the correction of tandem duplications. Further, there is a significant gap between the minimum redundancy of duplication correcting codes and burst insertion co 收起 • This paper generalizes the bordered-algebraic knot invariant introduced in an earlier paper, giving an invariant now with more algebraic structure. It also introduces signs to define these invariants with integral coefficients. We describe effective computations of the resulting invariant. 收起 • Solving the Rubik's Cube Optimally Is NP-Complete 收起 • 07-01 Hacker News 68 Way Cooler tiling window manager 收起 • Let p be a prime. For any finite p-group G, the deep transfers T(H,G'):H/H' --> G'/G'' from the maximal subgroups H of index (G:H)=p in G to the derived subgroup G' are introduced as an innovative tool for identifying G uniquely by means of the family of kernels kappa_d(G)=(ker(T(H,G')))_{(G:H)=p}. For all finite 3-groups G of coclass cc(G)=1, the family kappa_d(G) is determined explicitly. The results are applied to the Galois groups G=Gal(F_3^\infty/F) of the Hilbert 3-class towers of all real quadratic fields F=Q(d^1/2) with fundamental discriminants d>1, 3-class group Cl_3(F)~C_3*C_3, and total 3-principalization in each of their four unramified cyclic cubic extensions E/F. A systematic statistical evaluation is given for the complete range 1<d<5*10^6, and a few exceptional cases are pointed out for 1<d<64*10^6. 收起 • 07-01 Hacker News 67 Does Transparency Lead to Pay Compression? (2016) [pdf] 收起 • Pay-with-a-Selfie, a human-centred digital payment system 收起 • 07-01 Hacker News 76 Why Is It So Hard to Study Marijuana? 收起 • In mobile cellular networks, it is estimated that more than 60% of voice and data services occur indoors. Therefore, cellular network operators have shown an unprecedented interest in research on femtocell systems from various aspects to extend the indoor wireless coverage for providing high-quality and high data-rate wireless multimedia services contents. In an effort for reducing the bit-error probabilities (BEPs) and also increasing bit/symbol capacity of bandwidth limited error-prone wireless channels in femtocell propagation areas, this paper presents the performance of a promising candidate technology designed based on the state-of-the-art techniques. The performance of powerful space-time turbo codes (STTCs) based on serial concatenation of quadratic interleaved codes (SC-QICs) with the optimal and also suboptimal decoding algorithms, in conjunction with orthogonal space-time block codes (OSTBCs) have been presented in this contribution for wireless multiple-input single-output 收起 • This document briefly describes the Black-Box Multi-Objective Optimization Benchmarking (BMOBench) platform. It presents the test problems, evaluation procedure, and experimental setup. To this end, the BMOBench is demonstrated by comparing recent multi-objective solvers from the literature, namely SMS-EMOA, DMS, and MO-SOO. 收起 • In this article, we propose new Bayesian methods for selecting and estimating a sparse coefficient vector for skewed heteroscedastic response. Our novel Bayesian procedures effectively estimate the median and other quantile functions, accommodate non-local prior for regression effects without compromising ease of implementation via sampling based tools, and asymptotically select the true set of predictors even when the number of covariates increases in the same order of the sample size. We also extend our method to deal with some observations with very large errors. Via simulation studies and a re-analysis of a medical cost study with large number of potential predictors, we illustrate the ease of implementation and other practical advantages of our approach compared to existing methods for such studies. 收起 • A method is proposed for solving equality constrained nonlinear optimization problems involving twice continuously differentiable functions. The method employs a trust funnel approach consisting of two phases: a first phase to locate an$\epsilon$-feasible point and a second phase to seek optimality while maintaining at least$\epsilon$-feasibility. A two-phase approach of this kind based on a cubic regularization methodology was recently proposed along with a supporting worst-case iteration complexity analysis. Unfortunately, however, in that approach, the objective function is completely ignored in the first phase when$\epsilon$-feasibility is sought. The main contribution of the method proposed in this paper is that the same worst-case iteration complexity is achieved, but with a first phase that also accounts for improvements in the objective function. As such, the method typically requires fewer iterations in the second phase, as the results of numerical experiments demonstrate. 收起 • In the paper we study the models of time-changed Poisson and Skellam-type processes, where the role of time is played by compound Poisson-Gamma subordinators and their inverse (or first passage time) processes. We obtain explicitly the probability distributions of considered time-changed processes and discuss their properties. 收起 • We consider the remote vector source coding problem in which a vector Gaussian source is to be estimated from noisy linear measurements. For this problem, we derive the performance of the compress-and-estimate (CE) coding scheme and compare it to the optimal performance. In the CE coding scheme, the remote encoder compresses the noisy source observations so as to minimize the local distortion measure, independent from the joint distribution between the source and the observations. In reconstruction, the decoder estimates the original source realization from the lossy-compressed noisy observations. For the CE coding in the Gaussian vector case, we show that, if the code rate is less than a threshold, then the CE coding scheme attains the same performance as the optimal coding scheme. We also introduce lower and upper bounds for the performance gap above this threshold. In addition, an example with two observations and two sources is studied to illustrate the behavior of the performance 收起 • In this paper, we continue our understanding of the stable process from the perspective of the theory of self-similar Markov processes in the spirit of the recent papers of Kyprianou (2016) and Kyprianou et al. (2017). In particular, we turn our attention to the case of$d$-dimensional isotropic stable process, for$d\geq 2$. Using a completely new approach we consider the distribution of the point of closest reach. This leads us to a number of other substantial new results for this class of stable processes. We engage with a new radial excursion theory, never before used, from which we develop the classical Blumenthal--Getoor--Ray identities for first entry/exit into a ball, cf. Blumenthal et al. (1961), to the setting of$n$-tuple laws. We identify explicitly the stationary distribution of the stable process when reflected in its running radial supremum. Moreover, we provide a representation of the Wiener--Hopf factorisation of the MAP that underlies the stable process through the La 收起 • If$V$is an irreducible algebraic variety over a number field$K$, and$L$is a field containing$K$, we say that$V$is diophantine-stable for$L/K$if$V(L) = V(K)$. We prove that if$V$is either a simple abelian variety, or a curve of genus at least one, then under mild hypotheses there is a set$S$of rational primes with positive density such that for every$\ell \in S$and every$n \ge 1$, there are infinitely many cyclic extensions$L/K$of degree$\ell^n$for which$V$is diophantine-stable. We use this result to study the collection of finite extensions of$K$generated by points in$V(\bar{K})$. 收起 • We study the behavior of the spectrum of the Dirac operator together with a symmetric$W^{1, \infty}$-potential on spin manifolds under a collapse of codimension one with bounded sectional curvature and diameter. If there is an induced spin structure on the limit space$N$then there are convergent eigenvalues which converge to the spectrum of a first order differential operator$D$on$N$together with a symmetric$W^{1,\infty}$-potential. If the dimension of the limit space is even then$D$is the Dirac operator$D^N$on$N$and if the dimension of the limit space is odd, then$D = D^N \oplus -D^N$. 收起 • A mixed mimetic spectral element method is applied to solve the rotating shallow water equations. The mixed method uses the recently developed spectral element edge functions, which exactly satisfy the fundamental theorem of calculus with respect to the standard Lagrange basis functions in one dimension, in order to construct tensor product solution spaces which satisfy the generalized Stokes theorem, as well as the annihilation of the gradient operator by the curl. This allows for the exact conservation of first order moments (mass, vorticity), as well as quadratic moments (energy, potential enstrophy), subject to the truncation error of the time stepping scheme. The continuity equation is solved in the strong form, such that mass conservation holds point wise, while the momentum equation is solved in the weak form such that vorticity is globally conserved. While mass, vorticity and energy conservation hold for any quadrature rule, potential enstrophy conservation is dependent on exac 收起 • In this paper, distributed convex optimization problem over non-directed dynamical networks is studied. Here, networked agents with single-integrator dynamics are supposed to rendezvous at a point that is the solution of a global convex optimization problem with some local inequality constraints. To this end, all agents shall cooperate with their neighbors to seek the optimum point of the networks global objective function. A distributed optimization algorithm based on the interior-point method is proposed, which combines an optimization algorithm with a nonlinear consensus protocol to find the optimum value of the global objective function. We tackle this problem by addressing its sub-problems, namely a consensus problem and a convex optimization problem. Firstly, we propose a saturation protocol for the consensus sub-problem. Then to solve the distributed optimization part, we implement a centralized control law, which yields the optimum value of the global objective function, in a d 收起 • A Riemannian symmetric space is a Riemannian manifold in which it is possible to reflect all geodesics through a point by an isometry of the space. On such spaces, we introduce the notion of a distributional lattice, generalizing the notion of lattice. Distributional lattices exist in any Riemannian symmetric space: specifically the Voronoi tessellation of an stationary Poisson point process is an example. We show that for an appropriate notion of amenability, the amenability of a distributional lattice is equivalent to the amenability of the ambient space. Using this equivalence, we show that the simple random walk on any distributional lattice has positive embedded speed. For nonpositively curved, simply connected spaces, we show that the simple random walk on a Poisson--Voronoi tessellation has positive graph speed by developing some additional structure for Poisson--Voronoi tessellations. 收起 • A double Ore extension was introduced by James Zhang and Jun Zhang \cite{ZhZh} to study Artin-Schelter regular algebras. Here we give a definition of double Poisson extension which may be considered as a Poisson analogue of double Ore extension and show that algebras in a class of double Ore extensions are deformations of double Poisson extensions. We also investigate the relationship between double Poisson extensions and iterated Poisson polynomial extensions. Results are illustrated by examples. 收起 • Our aim is to establish relations between Drazin inverses of the pesudo-block matrix$(P,Q,R,S)$and the block matrix composed of$P,R,S,Q$, where$R^2=S^2=0$. Based on the relations, we give representations for Drazin inverses of the sum$P+Q+R+S$under weaker restrictions. As its applications, several expressions for Drazin inverses of a$2\times 2$block matrix are presented under some assumptions. Our results generalize several results in the literature. 收起 • In dynamic imaging, a key challenge is to reconstruct image sequences with high temporal resolution from strong undersampling projections due to a relatively slow data acquisition speed. In this paper, we propose a variational model using the infimal convolution of Bregman distance with respect to total variation to model edge dependence of sequential frames. The proposed model is solved via an alternating iterative scheme, for which each subproblem is convex and can be solved by existing algorithms. The proposed model is formulated under both Gaussian and Poisson noise assumption and the simulation on two sets of dynamic images shows the advantage of the proposed method compared to previous methods. 收起 • Recently, deep learning approaches have achieved significant performance improvement in various imaging problems. However, it is still unclear why these deep learning architectures work. Moreover, the link between the deep learning and the classical signal processing approaches such as wavelet, non-local processing, compressed sensing, etc, is still not well understood, which often makes signal processors in deep troubles. To address these issues, here we show that the long-searched-for missing link is the convolutional framelets for representing a signal by convolving local and non-local bases. The convolutional framelets was originally developed to generalize the recent theory of low-rank Hankel matrix approaches, and this paper significantly extends the idea to derive a deep neural network using multi-layer convolutional framelets with perfect reconstruction (PR) under rectified linear unit (ReLU). Our analysis also shows that the popular deep network components such as residual blo 收起 • We introduce three new cut tree structures of graphs$G$in which the vertex set of the tree is a partition of$V(G)$and contractions of tree vertices satisfy sparsification requirements that preserve various types of cuts. Recently, Kawarabayashi and Thorup \cite{Kawarabayashi2015a} presented the first deterministic near-linear edge-connectivity recognition algorithm. A crucial step in this algorithm uses the existence of vertex subsets of a simple graph$G$whose contractions leave a graph with$\tilde{O}(n/\delta)$vertices and$\tilde{O}(n)$edges ($n := |V(G)|$) such that all non-trivial min-cuts of$G$are preserved. We improve this result by eliminating the poly-logarithmic factors, that is, we show a contraction-based sparsification that leaves$O(n/\delta)$vertices and$O(n)$edges and preserves all non-trivial min-cuts. We complement this result by giving a sparsification that leaves$O(n/\delta)$vertices and$O(n)$edges such that all (possibly not minimum) cuts of size l 收起 • Massive MTC support is an important future market segment, but not yet efficiently supported in cellular systems. In this paper we follow-up on recent concepts combining advanced MAC protocols with Compressed Sensing (CS) based multiuser detection. Specifically, we introduce a concept for sparse joint activity, channel and data detection in the context of the Coded ALOHA (FDMA) protocol. We will argue that a simple sparse activity and data detection is not sufficient (as many papers do) because control resources are in the order of the data. In addition, we will improve on the performance of such protocols in terms of the reduction of resources required for the user activity, channel estimation and data detection. We will mathematically analyze the system accordingly and provide expressions for the capture probabilities of the underlying sparse multiuser detector. Finally, we will provide structured CS algorithms for the joint estimation scheme and evaluate its performance. 收起 • The computation of the tropical prevariety is the first step in the application of polyhedral methods to compute positive dimensional solution sets of polynomial systems. In particular, pretropisms are candidate leading exponents for the power series developments of the solutions. The computation of the power series may start as soon as one pretropism is available, so our parallel computation of the tropical prevariety has an application in a pipelined solver. We present a parallel implementation of dynamic enumeration. Our first distributed memory implementation with forked processes achieved good speedups, but quite often resulted in large variations in the execution times of the processes. The shared memory multithreaded version applies work stealing to reduce the variability of the run time. Our implementation applies the thread safe Parma Polyhedral Library (PPL), in exact arithmetic with the GNU Multiprecision Arithmetic Library (GMP), aided by the fast memory allocations of TCMa 收起 • We study the sets that are computable from both halves of some (Martin-L\"of) random sequence, which we call \emph{$1/2$-bases}. We show that the collection of such sets forms an ideal in the Turing degrees that is generated by its c.e.\ elements. It is a proper subideal of the$K$-trivial sets. We characterise$1/2$-bases as the sets computable from both halves of Chaitin's$\Omega$, and as the sets that obey the cost function$\mathbf c(x,s) = \sqrt{\Omega_s - \Omega_x}$. Generalising these results yields a dense hierarchy of subideals in the$K$-trivial degrees: For$k< n$, let$B_{k/n}$be the collection of sets that are below any$k$out of$n$columns of some random sequence. As before, this is an ideal generated by its c.e.\ elements and the random sequence in the definition can always be taken to be$\Omega$. Furthermore, the corresponding cost function characterisation reveals that$B_{k/n}$is independent of the particular representation of the rational$k/n$, and that$B_

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• In this paper we focus on the finite-dimensional approximation of quasi-static evolutions of critical points of the phase-field model of brittle fracture. In a space discretized setting, we first discuss an alternating minimization scheme which, together with the usual time-discretization procedure, allows us to construct such finite-dimensional evolutions. Then, passing to the limit as the space discretization becomes finer and finer, we prove that any limit of a sequence of finite-dimensional evolutions is itself a quasi-static evolution of the phase-field model of fracture. In particular, our proof shows for the first time the consistency of numerical schemes related to the study of fracture mechanics and image processing.

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• The exact recovery property of Basis pursuit (BP) and Orthogonal Matching Pursuit (OMP) has a relation with the coherence of the underlying frame. A frame with low coherence provides better guarantees for exact recovery. In particular, Incoherent Unit Norm Tight Frames (IUNTFs) play a significant role in sparse representations. IUNTFs with special structure, in particular those given by a union of several orthonormal bases, are known to satisfy better theoretical guarantees for recovering sparse signals. In the present work, we propose to construct structured IUNTFs consisting of large number of orthonormal bases. For a given $r, k, m$ with $k$ being less than or equal to the smallest prime power factor of $m$ and $r<k,$ we construct a CS matrix of size $mk \times (mk\times m^{r})$ with coherence at most $\frac{r}{k},$ which consists of $m^{r}$ number of orthonormal bases and with density $\frac{1}{m}$. We also present numerical results of recovery performance of union of orthonorma

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• In this paper, convergence of a characteristics-based hybrid method recently introduced in Daripa & Dutta (J. Comput. Phys., 335:249-282, 2017) has been proved. This method which combines a discontinuous finite element method and a modified method of characteristics (MMOC) has been successfully applied to solve a coupled, nonlinear system of elliptic and transport equations that arise in multicomponent two-phase porous media flows. The novelty in this paper is the convergence analysis of the MMOC procedure for a nonlinear system of transport equations. For this purpose, an analogous single-component system of transport equations has been considered and possible extension to multicomponent systems has been discussed. Error estimates have been obtained and these estimates have also been validated by realistic numerical simulations of flows arising in enhanced oil recovery processes.

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• That a monotone, stable, and consistent scheme converges to the viscosity solution of a fully nonlinear second order local equation satisfying a comparison principle is a seminal result in the viscosity theory. We extend these ideas in a very general manner to weakly nonlocal equations and apply our results to obtain convergent schemes for finite and infinite-horizon equations arising from impulse control, including a new "stochastic semi-Lagrangian" scheme that is fully explicit, unconditionally stable, trivially monotone in higher dimensions, and embarrassingly parallel.

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• Convolutional dictionary learning (CDL or sparsifying CDL) has many applications in image processing and computer vision. There has been growing interest in developing efficient algorithms for CDL, mostly relying on the augmented Lagrangian (AL) method or the variant alternating direction method of multipliers (ADMM). When their parameters are properly tuned, AL methods have shown fast convergence in CDL. However, the parameter tuning process is not trivial due to its data dependence and, in practice, the convergence of AL methods depends on the AL parameters for nonconvex CDL problems. To moderate these problems, this paper proposes a new practically feasible and convergent Block Proximal Gradient method using a Majorizer (BPG-M) for CDL. The BPG-M-based CDL is investigated with different block updating schemes and majorization matrix designs, and further accelerated by incorporating some momentum coefficient formulas and restarting techniques. All of the methods investigated incorpor

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• In this paper we determine the projective unitary representations of finite dimensional Lie supergroups whose underlying Lie superalgebra is $\frak{g} = A \otimes \frak{k}$, where $\frak{k}$ is a compact simple Lie superalgebra and $A$ is a supercommutative associative (super)algebra; the crucial case is when $A = \Lambda_s(\mathbb{R})$ is a Gra\ss{}mann algebra. Since we are interested in projective representations, the first step consists of determining the cocycles defining the corresponding central extensions. Our second main result asserts that, if $\frak{k}$ is a simple compact Lie superalgebra with $\frak{k}_1\neq \{0\}$, then each (projective) unitary representation of $\Lambda_s(\mathbb{R})\otimes \frak{k}$ factors through a (projective) unitary representation of $\frak{k}$ itself, and these are known by Jakobsen's classification. If $\frak{k}_1 = \{0\}$, then we likewise reduce the classification problem to semidirect products of compact Lie groups $K$ with a Clifford--Lie su

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• The correlations of multiple renewable power plants (RPPs) should be fully considered in the power system with very high penetration renewable power integration. This paper models the uncertainties, spatial correlation of multiple RPPs based on Copula theory and actual probability historical histograms by one-dimension distributions for economic dispatch (ED) problem. An efficient dynamic renewable power scenario generation method based on Gibbs sampling is proposed to generate renewable power scenarios considering the uncertainties, spatial correlation and variability (temporal correlation) of multiple RPPs, in which the sampling space complexity do not increase with the number of RPPs. Distribution-based and scenario-based methods are proposed and compared to solve the real-time ED problem with multiple RPPs. Results show that the proposed dynamic scenario generation method is much more consist with the actual renewable power. The proposed ED methods show better understanding for the

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• This week’s most thought-provoking papers from the Physics arXiv.

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•   07-01 Hacker News 79

Solving the Mystery of Whose Laughter Is On the Golden Record

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•   07-01 Hacker News 80

The Accumulibrary (2014)

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•   07-01 Hacker News 83

The case of the 500-mile email (2002)

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•   07-01 Slashdot 79

As trust and familiarity with sharing economy services continues to grow, so too will the number of users, estimates marketing research firm eMarketer. From the article: Over a quarter (26.0%) of US adult internet users -- or 56.5 million people -- will use a sharing economy service at least once in 2017. This is a higher figure than previously projected due to stronger-than-expected uptake of both ride- and home-sharing services. This year, 16.9% of US adult internet users are expected to use their Airbnb account at least once, equating to 36.8 million people.

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•   07-01 Hacker News 78

Walmart threatens to cut ties with truckers that also haul for Amazon

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•   07-01 Hacker News 80

What is ‘skip locked’ for in PostgreSQL 9.5? (2016)

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