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Longtime Slashdot reader theodp writes: In Valley of Genius: The Uncensored History of Silicon Valley (As Told by the Hackers, Founders, and Freaks Who Made It Boom), Adam Fisher paints quite a different picture of life at nowworkforce behavior preachers Google and Facebook, revealing that the tech giants' formative days were filled with the kind of antics that run afoul of HR protocols. Google was not a normal place, begins an excerpt in Vanity Fair that includes some juicy quotes attributed to Google executive chef Charlie Ayers about Google's founders ("Sergey's the Google playboy. He was known for getting his fingers caught in the cookie jar with employees that worked for the company in the masseuse room. He got around.") And in Sex, Beer, and Coding, Wired runs an excerpt about Facebook's wild early days, which even extended to the artwork gracing its office ("The office was on the second floor, so as you walk in you immediately have to walk up some stairs, and on the big 10foot
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An anonymous reader writes: "Login passwords for tens of thousands of Dahua devices have been cached inside search results returned by ZoomEye, a search engine for discovering Internetconnected devices (also called an IoT search engine)," reports Bleeping Computer. A security researcher has recently discovered that instead of just indexing IoT devices, ZoomEye is also sending an exploitation package to devices and caching the results, which also include cleartext DDNS passwords that allow an attacker remote access to these devices. Searching for the devices is trivial and simple queries can unearth tens of thousands of vulnerable Dahua DVRs. According to the security researcher who spotted these devices, the trick has been used in the past year by the author of the BrickerBot IoT malware, the one who was on a crusade last year, bricking unsecured devices in an attempt to have them go offline instead of being added to IoT botnets.
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An anonymous reader shares a report: A prestigious college in Beijing that reportedly tried to bar a student because his father was on a government blacklist is causing huge controversy in China. According to state media reports, a high school student with the surname Rao in the eastern city of Wenzhou, in Zhejiang province, was accepted on the back of his score in China's fiendishly difficult and incredibly competitive national college entrance exam. But before his family could enjoy Rao's accomplishments, the college notified them he may not be able to attend because of his father's poor credit standing  the father owed 200,000 RMB (about $30,000) to a local bank, and had been put on a blacklist dubbed the "lost trust list" for individuals with bad social standing, state media reported. Blacklists are a key feature of China's controversial "social credit system"  a set of government programs that sets up both incentives and disincentives to encourage people to behave in socially
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Shoppers taking part in internet giant Amazon's Prime Day are being told that the deals on offer may not be the cheapest available. From a report: Amazon said it has never claimed that Prime Day is necessarily the cheapest time to shop on its site. It comes after consumer group Which? warned customers that apparent bargains are not always as good as they seem. It said some goods can actually be cheaper at other times of the year, and advised shoppers to do their research. The 36 hour sale  aimed at subscribers to the Prime shopping service  offers discounts on a range of goods. The deals are timelimited, with shoppers being told that some items are only available while stocks last.
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Chrome is getting a major redesign soon, and this week new changes have started to land in the Chrome's nightly "Canary" build. Google is launching a new version of Material Design across its products, called the "Google Material Theme," and after debuting in Android P and Gmail.com, it's starting to roll out across other Google's major products. On Chrome, this means major changes to the tab and address bar. I haven't tried the new redesign yet  I don't use Chrome anyway  but judging by the screenshots, I can't say I'm a fan.
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The Debian project is pleased to announce the fifth update of its stable distribution Debian 9 (codename stretch). This point release mainly adds corrections for security issues, along with a few adjustments for serious problems. Security advisories have already been published separately and are referenced where available. Please note that the point release does not constitute a new version of Debian 9 but only updates some of the packages included. There is no need to throw away old stretch media. After installation, packages can be upgraded to the current versions using an uptodate Debian mirror. I'm not a fan of publishing items for every single distribution release  other sites do that way better than I ever could  but there are a few distributions I do try to keep up with, and considering just how fundamental Debian is to many popular Linux distributions, it's always been an exception.
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It seems like everyone these days has had a paranoiac moment where a website advertises something to you that you recently purchased or was gifted without a digital trail. According to a new website called New Organs, which collects firsthand accounts of these moments, "the feeling of being listened to is among the most common experiences, along with seeing the same ads on different websites, and being tracked via geolocation," reports The Outline. The website was created by Tega Brain and Sam Lavigne, two Brooklynbased artists whose work explores the intersections of technology and society. From the report: "We are stuck in this 20th century idea of spying, of wiretapping and hidden microphones," said Brain. "But really there is this whole new sensory apparatus, a complicated entanglement of online trackers and algorithms that are watching over us." It is this new sensory apparatus that Brain and Lavigne metaphorically refer to as "new organs," as if the online surveillance framewo
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Facebook is trying to get Instagram users to visit its site more often by further entwining the two services. According to Instagram user Spencer Chen, the Instagram app prompted him to check out a friend's new photo on Facebook. "Chen grabbed a screenshot and posted the notification on the internet, calling it a cry for attention by the older social network," reports Bloomberg. From the report: Instagram says what Chen experienced was a product test with a small contingent of users. Still, Instagram feeds Facebook in other ways. Last year, Facebook launched its own version of an Instagram tool called Stories, which lets people post videos that disappear within 24 hours. (The feature was initially copied from Snap Inc., a competitor.) Greenfield noticed the Facebook version became more popular once it became possible for Instagram users to post their stories in both places with the click of a button. Instagram Stories' 400 million users present a significant opportunity for Facebook's
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We study the global existence of solutions to semilinear wave equations with powertype nonlinearity and general lower order terms on $n$ dimensional nontrapping asymptotically Euclidean manifolds, when $n=3, 4$. In addition, we prove almost global existence with sharp lower bound of the lifespan for the four dimensional critical problem.
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By $I$method, the interaction Morawetz estimate, long time Strichartz estimate and local smoothing effect of Schr\"odinger operator, we show global wellposedness and scattering for the defocusing Hartree equation $$\left\{ \begin{array}{ll} iu_t + \Delta u &=F(u), \quad (t,x) \in \mathbb{R} \times \mathbb{R}^4 u(0) \\ &=u_0(x)\in H^s(\mathbb{R}^4), \end{array} \right. $$ where $F(u)= (V* u^2) u$, and $V(x)=x^{\gamma}$, $3< \gamma<4$, with radial data in $H^{s}(\mathbb{R}^4)$ for $s>s_c:=\gamma/21$. It is a sharp global result except of the critical case $s=s_c$, which is a very difficult open problem.
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Quadratic programming (QP) is a wellstudied fundamental NPhard optimization problem which optimizes a quadratic objective over a set of linear constraints. In this paper, we reformulate QPs as a mixedinteger linear problem (MILP). This is done via the reformulation of QP as a linear complementary problem, and the use of binary variables and bigM constraints, to model the complementary constraints. To obtain such reformulation, we show how to impose bounds on the dual variables without eliminating all the (globally) optimal primal solutions; using some fundamental results on the solution of perturbed linear systems. Reformulating nonconvex QPs as MILPs provides an advantageous way to obtain global solutions as it allows the use of current stateoftheart MILP solvers. To illustrate this, we compare the performance of our solution approach, labeled quadprogIP, with the current benchmark global QP solver quadprogBB, as well as with BARON, one of the leading nonlinear programming (N
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We study Green functions for stationary Stokes systems satisfying the conormal derivative boundary condition. We establish existence, uniqueness, and various estimates for the Green function under the assumption that weak solutions of the Stokes system are continuous in the interior of the domain. Also, we establish the global pointwise bound for the Green function under the additional assumption that weak solutions of the conormal derivative problem for the Stokes system are locally bounded up to the boundary. We provide some examples satisfying such continuity and boundedness properties.
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Statistical sufficiency formalizes the notion of data reduction. In the decision theoretic interpretation, once a model is chosen all inferences should be based on a sufficient statistic. However, suppose we start with a set of procedures rather than a specific model. Is it possible to reduce the data and yet still be able to compute all of the procedures? In other words, what functions of the data contain all of the information sufficient for computing these procedures? This article presents some progress towards a theory of "computational sufficiency" and shows that strong reductions can be made for large classes of penalized $M$estimators by exploiting hidden symmetries in the underlying optimization problems. These reductions can (1) reveal hidden connections between seemingly disparate methods, (2) enable efficient computation, (3) give a different perspective on understanding procedures in a modelfree setting. As a main example, the theory provides a surprising answer to the fo
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In this article, we consider the Parabolic Anderson Model with constant initial condition, driven by a spacetime homogeneous Gaussian noise, with general covariance function in time and spatial spectral measure satisfying Dalang's condition. First, we prove that the solution (in the Skorohod sense) exists and is continuous in $L^p(\Omega)$. Then, we show that the solution has a modification whose sample paths are H\"older continuous in space and time, with optimal exponents, and under the minimal condition on the spatial spectral measure of the noise (which is the same as the condition encountered in the case of the white noise in time). This improves similar results which were obtained in Hu, Huang, Nualart and Tindel (2015), and Song (2017) under more restrictive conditions, and with suboptimal exponents for H\"older continuity.
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In this paper, we first give a direct proof for two recurrence relations of the heat kernels for hyperbolic spaces in \cite{DM}. Then, by similar computation, we give two similar recurrence relations of the heat kernels for spheres. Finally, as an application, we compute the diagonal of heat kernels for odd dimensional hyperbolic spaces and the heat trace asymptotic expansions for odd dimensional spheres.
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We solve the superhedging problem for European options in a market with finite liquidity where trading has transient impact on prices, and possibly a permanent one in addition. Impact is multiplicative to ensure positive asset prices. Hedges and option prices depend on the physical and cash delivery specifications of the option settlement. For noncovered options, where impact at the inception and maturity dates matters, we characterize the superhedging price as a viscosity solution of a degenerate semilinear pde that can have gradient constraints. The nonlinearity of the pde is governed by the transient nature of impact through a resilience function. For covered options, the pricing pde involves gamma constraints but is not affected by transience of impact. We use stochastic target techniques and geometric dynamic programming in reduced coordinates.
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Sliceregular functions of a quaternionic variable have been studied extensively in the last 12 years, resulting, in many ways, quite close to classical holomorphic functions of a complex variable; indeed, there is a correspondence between sliceregular functions and a certain family of holomorphic maps from the complex plane to $\mathbb{C}^4$, as noted by Ghiloni and Perotti. However, such a construction does not seem to offer any insight on the behaviour of sliceregular functions, due to the lack of a connection between the values of the holomorphic map and the values of the associated sliceregular function. The aim of this work is to show that there is indeed a (complex) geometric way to relate the values of this two functions, thus relating more deeply the world of holomorphic functions with that of sliceregular functions.
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We consider the assembly map for principal bundles with fiber a countable discrete group. We obtain an indextheoretic interpretation of this homomorphism by providing a tensorproduct presentation for the module of sections associated to the Mi\v{s}\v{c}enko line bundle. In addition, we give a proof of Atiyah's $L^2$index theorem in the general context of principal bundles over compact Hausdorff spaces. We thereby also reestablish that the surjectivity of the BaumConnes assembly map implies the KadisonKaplansky idempotent conjecture in the torsionfree case. Our approach does not rely on geometric $K$homology but rather on an explicit construction of AlexanderSpanier cohomology classes coming from a Chern character for tracial function algebras.
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Let $A$ be a free hyperplane arrangement. In 1989, Ziegler showed that the restriction $A''$ of $A$ to any hyperplane endowed with the natural multiplicity is then a free multiarrangement. We initiate a study of the stronger freeness property of inductive freeness for these canonical free multiarrangements and investigate them for the underlying class of reflection arrangements. More precisely, let $A = A(W)$ be the reflection arrangement of a complex reflection group $W$. By work of Terao, each such reflection arrangement is free. Thus so is Ziegler's canonical multiplicity on the restriction $A''$ of $A$ to a hyperplane. We show that the latter is inductively free as a multiarrangement if and only if $A''$ itself is inductively free.
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In 2006 Carbery raised a question about an improvement on the na\"ive norm inequality $\f+g\_p^p \leq 2^{p1}(\f\_p^p + \g\_p^p)$ for two functions in $L^p$ of any measure space. When $f=g$ this is an equality, but when the supports of $f$ and $g$ are disjoint the factor $2^{p1}$ is not needed. Carbery's question concerns a proposed interpolation between the two situations for $p>2$. The interpolation parameter measuring the overlap is $\fg\_{p/2}$. We prove an inequality of this type that is stronger than the one Carbery proposed. Moreover, our stronger inequalities are valid for all $p$.
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In this work we present new scalable, information theorybased variational methods for the efficient model reduction of highdimensional reaction networks. The proposed methodology combines, (a) information theoretic tools for sensitivity analysis that allow us to identify the proper coarse variables of the reaction network, with (b) variational approximate inference methods for training a bestfit reduced model. The overall approach takes advantage of both physicochemical modeling and databased approaches and allows to construct optimal parameterized reduced dynamics in the number of species, reactions and parameters, while controlling the information loss due to the reduction. We demonstrate the effectiveness of our model reduction method on several complex, highdimensional biochemical reaction networks from the recent literature.
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We provide an algorithm to estimate the divergence degree of the Lorentzian EPRLFK spin foam amplitudes for arbitrary 2complexes. We focus on the "selfenergy" and "vertex renormalization" diagrams and find an upper bound estimate. We argue that our upper bound must be close to the actual value, and explain what numerical improvements are needed to verify this numerically. For the selfenergy, this turns out to be significantly more divergent than the lower bound estimate present in the literature. We support the validity of our algorithm using 3stranded versions of the amplitudes (corresponding to a toy 3d model) for which our estimates are confirmed numerically. We also apply our methods to the simplified EPRLs model, finding a completely convergent behavior, and to BF theory, independently recovering the divergent estimates present in the literature.
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Lattice polytopes which possess the integer decomposition property (IDP for short) turn up in many fields of mathematics. It is known that if the Cayley sum of lattice polytopes possesses IDP, then so does their Minkowski sum. In this paper, the Cayley sum of the order polytope of a finite poset and the stable set polytope of a finite simple graph is studied. We show that the Cayley sum of an order polytope and the stable set polytope of a perfect graph possesses a regular unimodular triangulation and IDP, and hence so does their Minkowski sum. Moreover it turns out that, for an order polytope and the stable set polytope of a graph, the following conditions are equivalent: (i) the Cayley sum is Gorenstein; (ii) the Minkowski sum is Gorenstein; (iii) the graph is perfect.
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This paper explores the coexistence of a macro cell and a small cell for heterogeneous cellular networks, where a macro base station (MBS) and small base station (SBS) transmit to respective macro user (MU) and small user (SU) through their shared spectrum in the face of a common eavesdropper. We consider two spectrum sharing mechanisms, namely the overlay spectrum sharing (OSS) and underlay spectrum sharing (USS). In the OSS, MBS and SBS take turns to access their shared spectrum. By contrast, the USS allows MBS and SBS to simultaneously transmit over the shared spectrum with the aid of power control for limiting their mutual interference, thus called interferencelimited USS (ILUSS). In order to take advantage of mutual interference in confusing the eavesdropper without causing adverse effect on the MU, we propose an interferencecanceled USS (ICUSS) scheme. Closedform expressions of overall outage probability and intercept probability are derived for OSS, ILUSS and ICUSS schem
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In the paper, we consider the Inviscid, incompressible and semiclassical limits limits of the barotropic quantum NavierStokes equations of compressible flows in a periodic domain. We show that the limit solutions satisfy the incompressible Euler system based on the relative entropy inequality and on the detailed analysis for general initial data. The rate of convergence is estimated in terms of the Mach number.
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Classical toric varieties are constructed from rational fans in real vector spaces. Motivated by applications of algebraic geometry, given an arbitrary fan in R^n we construct an (R_>)^nequivariant cell complex, which we call an irrational toric variety. When the fan is rational, the irrational toric variety is the nonnegative part of the corresponding classical toric variety. When the fan is the normal fan of a polytope, the irrational toric variety is projective (may be embedded in a simplex) and it is homeomorphic to that polytope. We use these irrational toric varieties to identify the space of degenerations of a projective irrational toric variety with the secondary polytope of a point configuration.
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Given a quasilattice ordered group $(G,P)$ and a compactly aligned product system $X$ of essential C$^*$correspondences over the monoid $P$, we show that there is a bijection between the gaugeinvariant KMS$_\beta$states on the NicaToeplitz algebra $\mathcal{NT}(X)$ of $X$ with respect to a gaugetype dynamics, on one side, and the tracial states on the coefficient algebra $A$ satisfying a system (in general infinite) of inequalities, on the other. This strengthens and generalizes a number of results in the literature in several directions: we do not make any extra assumptions on $P$ and $X$, and our result can, in principle, be used to study KMSstates at any finite inverse temperature $\beta$. Under fairly general additional assumptions we show that there is a critical inverse temperature $\beta_c$ such that for $\beta>\beta_c$ all KMS$_\beta$states are of Gibbs type, hence gaugeinvariant, in which case we have a complete classification of KMS$_\beta$states in terms of trac
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We present a null model for single and multilayered complex systems constructed using homogeneous and isotropic random Gaussian maps. By means of a KacRice formalism, we show that the mean number of fixed points can be calculated as the expectation of the absolute value of the characteristic polynomial for a product of independent Gaussian (Ginibre) matrices. Furthermore, using techniques from Random Matrix Theory, we show that the highdimensional limit of our system has a thirdorder phase transition between a phase with a single fixed point and a phase with exponentially many fixed points. This is result is universal in the sense that it does not depend on finer details of the correlations for the random maps.
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Let (Y, Z) denote the solution to a forwardbackward SDE. If one constructs a random walk B n from the underlying Brownian motion B by Skorohod embedding, one can show L 2 convergence of the corresponding solutions (Y n , Z n) to (Y, Z). We estimate the rate of convergence in dependence of smoothness properties, especially for a terminal condition function in C 2,$\alpha$. The proof relies on an approximative representation of Z n and uses the concept of discretized Malliavin calculus. Moreover, we use growth and smoothness properties of the PDE associated to the FBSDE as well as of the finite difference equations associated to the approximating stochastic equations. We derive these properties by stochastic methods.
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Narrowband IoT (NBIoT) is the latest IoT connectivity solution presented by the 3GPP. NBIoT introduces coverage classes and introduces a significant link budget improvement by allowing repeated transmissions by nodes that experience high path loss. However, those repetitions necessarily increase the energy consumption and the latency in the whole NBIoT system. The extent to which the whole system is affected depends on the scheduling of the uplink and downlink channels. We address this question, not treated previously, by developing a tractable model of NBIoT access protocol operation, comprising message exchanges in randomaccess, control, and data channels, both in the uplink and downlink. The model is then used to analyze the impact of channel scheduling as well as the interaction of coexisting coverage classes, through derivation of the expected latency and battery lifetime for each coverage class. These results are subsequently employed in investigation of latencyenergy trade
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In this paper, motivated by finding sharp LiYau type gradient estimate for positive solution of heat equations on complete Riemannian manifolds with negative Ricci curvature lower bound, we first introduce the notion of LiYau multiplier set and show that it can be computed by heat kernel of the manifold. Then, an optimal LiYau type gradient estimate is obtained on hyperbolic spaces by using recurrence relations of heat kernels on hyperbolic spaces. Finally, as an application, we obtain sharp Harnack inequalities on hyperbolic spaces.
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We construct an infinite dimensional Lie rackoid Y which hosts an integration of the standard Courant algebroid. As a set, Y = C $\infty$ ([0, 1], T * M) for a compact manifold M. The rackoid product is by automorphisms of the Dorfman bracket. The first part of the article is a study of the Lie rackoid Y and its tangent Leibniz algebroid a quotient of which is the standard Courant algebroid. In a second part, we study the equivalence relation related to the quotient on the rackoid level and restrict then to an integrable Dirac structure. We show how our integrating object contains the corresponding integrating Weinstein Lie groupoid in the case where the Dirac structure is given by a Poisson structure.
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