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Chinesedesigned "Dhyana" x86 processors based on AMD's Zen microarchitecture are beginning to surface from Chinese chip producer Hygon. The processors come as the fruit of AMD's x86 IP licensing agreements with its Chinabased partners and break the decadeslong stranglehold on x86 held by the triumvirate of Intel, AMD and VIA Technologies. Details are also emerging that outline how AMD has managed to stay within the boundaries of the x86 licensing agreements but still allow Chinesecontrolled interests to design and sell processors based on the Zen design. Even though I doubt this will have any meaningful impact on competition, it's always good to see new x86 manufacturers. The licensing situation around x86 always feels impenetrable and mysterious to me, almost as if it was specifically designed and set up to divide up the x86 market, a huge cash cow for several decades now. With ARM use being on the rise and the architecture even making its first inroads into laptops, serve
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From a report: It is the most exacting of surgical skills: tying a knot deep inside a patient's abdomen, pivoting long graspers through keyhole incisions with no direct view of the thread. Trainee surgeons typically require 60 to 80 hours of practice, but in a mockup operating theatre outside Cambridge, a nonmedic with just a few hours of experience is expertly wielding a hookshaped needle  in this case stitching a square of pink sponge rather than an artery or appendix. The feat is performed with the assistance of Versius, the world's smallest surgical robot, which could be used in NHS operating theatres for the first time later this year if approved for clinical use. Versius is one of a handful of advanced surgical robots that are predicted to transform the way operations are performed by allowing tens or hundreds of thousands more surgeries each year to be carried out as keyhole procedures. The Versius robot cuts down the time required to learn to tie a surgical knot from more
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We generalize Kato's adiabatic theorem to nonunitary dynamics. This enables us to unify two strong coupling limits: one driven by fast oscillations under a Hamiltonian, and the other driven by strong damping under a Lindbladian. We discuss the case where both mechanisms are present and provide nonperturbative error bounds. We also analyze the links with the quantum Zeno effect and dynamics.
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We generalize Kato's adiabatic theorem to nonunitary dynamics. This enables us to unify two strong coupling limits: one driven by fast oscillations under a Hamiltonian, and the other driven by strong damping under a Lindbladian. We discuss the case where both mechanisms are present and provide nonperturbative error bounds. We also analyze the links with the quantum Zeno effect and dynamics.
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In the 4.18 kernel, a new feature was merged to allow infrared (IR) decoding to be done using BPF. Infrared remotes use many different encodings; if a decoder were to be written for each, we would end up with hundreds of decoders in the kernel. So, currently, the kernel only supports the most widely used protocols. Alternatively, the lirc daemon can be run to decode IR. Decoding IR can usually be expressed in a few lines of code, so a more lightweight solution without many kerneltouserspace context switches would be preferable. This article will explain how IR messages are encoded, the structure of a BPF program, and how a BPF program can maintain state between invocations. It concludes with a look at the steps that are taken to end up with a button event, such as a volumeup key event.
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CNET reported this week that a musician, who plays guitar and has lots of viewers on YouTube, received an unusual email from the company alleging that he had copied a tune he wrote himself two years ago. From the report: But last month, Paul Davids says he got a rather unusual email from YouTube. The Content ID system had flagged a tune he wrote himself, two years ago, for infringing on someone's else's newer video. Someone who, it seems, stole his backing track to create a new track of his own. [...] "Someone took my track, made their own track, uploaded it to Spotify, YouTube, whatever, and I get a copyright infringement notice? Wait, what?" said Davids. The story has a happy ending  Davids used YouTube's appeals system to quickly work things out, and let the other artist keep on using his tune. (Davids tracked him down on Facebook Messenger, and the guy apparently admitted he'd downloaded 'a couple of guitar licks' on YouTube.) But it's weird to think YouTube would flag an old vid
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An anonymous reader quotes a report from Engadget: If you're familiar with the phrase "that's a terrible idea, let's do it" then you might be one of the British MPs who think that the UK should do its own version of FOSTASESTA. That's exactly what Labour MP Sarah Champion has done by leading a debate this week for the creation of laws to criminalize websites used by sex workers in the UK  under the rubric of fighting trafficking, of course. A selfappointed group of MPs (the "AllParty Parliamentary Group on Prostitution and the Global Sex Trade") fronted by Ms. Champion made a call to ban "prostitution websites" during a Wednesday House of Commons debate. Conflating sex work with trafficking just like their American counterparts, they claim websites where workers advertise and screen clients "directly and knowingly" profit from sex trafficking.
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A recently discovered hole in Valve's API allowed observers to generate extremely precise and publicly accessible data for the total number of players for thousands of Steam games. While Valve has now closed this inadvertent data leak, Ars can still provide the data it revealed as a historical record of the aggregate popularity of a large portion of the Steam library. From the report: The new data derivation method, as ably explained in a Medium post from The End Is Nigh developer Tyler Glaiel, centers on the percentage of players who have accomplished developerdefined Achievements associated with many games on the service. On the Steam web site, that data appears rounded to two decimal places. In the Steam API, however, the Achievement percentages were, until recently, provided to an extremely precise 16 decimal places. This added precision means that many Achievement percentages can only be factored into specific whole numbers. (This is useful since each game's player count must be
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An anonymous reader quotes a report from the BBC: Professor Veena Sahajwalla's mine in Australia produces gold, silver and copper  and there isn't a pickaxe in sight. Her "urban mine" at the University of New South Wales (UNSW) is extracting these materials not from rock, but from electronic gadgets. The Sydneybased expert in materials science reckons her operation will become efficient enough to be making a profit within a couple of years. "Economic modeling shows the cost of around $500,000 Australian dollars for a microfactory pays off in two to three years, and can generate revenue and create jobs," she says. "That means there are environmental, social and economic benefits." In fact, research indicates that such facilities can actually be far more profitable than traditional mining. According to a study published recently in the journal Environmental Science & Technology, a typical cathoderay tube TV contains about 450g of copper and 227g of aluminum, as well as around 5
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Kenya will reportedly use Alphabet's system of internet balloons to connect its rural population to the web. The balloons, known as Project Loon, were developed by Alphabet's X, the company's innovation lab. It was recently used by U.S. telecom operators to provide connectivity to people in Puerto Rico after a hurricane last year. Reuters reports: Joe Mucheru, the information, communication and technology minister, told Reuters on Wednesday that project representatives were holding talks with local telecom operators on the deployment of the technology. "The Loon team are still working out contracts and hopefully once that is done, we can be able to see almost every part of the country covered," he said. With more than 45 million people, Kenya's major cities and towns are covered by operator networks, but vast swathes of rural Kenya are not covered. "Loon is another technology that is being introduced that the licensed operators hopefully can be able to use," Mucheru said, adding it wou
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Slashdot reader Dave Knott brings news: Steve Ditko, the legendary comics artist best known for cocreating SpiderMan and Doctor Strange, has died at age 90. No cause of death was announced. Neil Gaiman posted on Twitter, "I know I'm a different person because he was in the world." Entertainment Weekly reports: Ditko's most enduring characters were created during his tenure at Marvel Comics, where he worked alongside editorinchief Stan Lee to develop the look of SpiderMan in 1961. Jack Kirby had previously taken a swing at the webslinger, but Lee was unconvinced by that artist's interpretation of the nowiconic character. When SpiderMan  whose redandblue costume, Spidey senses, and webshooters all came directly from Ditko  first appeared within the pages of Amazing Fantasy No. 15, the friendly neighborhood superhero proved a surprisingly massive hit for Marvel Comics, paving the way for a solo comic series titled The Amazing SpiderMan. Ditko's influence on SpiderMan w
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According to The Washington Post, Twitter has suspended 70 million accounts in the past two months as part of a crackdown on malicious activity on its platform. "The rate of suspensions for May and June is reportedly twice the company's October 2017 suspension rate," reports The Verge. From the report: In a blog post last month, Twitter said it had been working to improve its safety policies, and that its "systems identified and challenged more than 9.9 million potentially spammy or automated accounts per week." The Post reports that the change in enforcement could cause a decline in users for the company's second quarter, although a Twitter executive told the publication that many of the accounts rarely tweeted, and would therefore not dramatically impact the company's active user count. A Twitter spokesperson said in a statement to The Verge that the company noted in its firstquarter shareholder letter this year that âoeongoing information quality effortsâ had negatively i
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Slashdot reader yeokm1 recently installed Linux on a 1993 PC. But in a new blog post he lists every keyboard he's owned over the last 12 years  to explain why he's now typing on a 5.3pound Model M keyboard from 1987 that's older than he is, "with its legendary bucklingspring switch." It'll probably last me the decades to the day that keyboards should become obsolete... It is sad that with all the advancements in computing, the one piece of equipment that we use the most to interact with our computers has regressed technologically in the name of costs. We don't usually expect to be using 30yearold hardware on a daily productive basis but the IBM Model M keyboard is that exception. Today, I don't really care about fancy features like great aesthetics, RGB backlights, media keys and extra USB ports. I just need something that gives me great tactile feedback, be durable, enable me to easily swap keys to fit my Programmer Dvorak layout. The Model M fits my needs perfectly. "Really c
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We study $(\sigma,\tau)$derivations of a group ring $RG$ of a finite group $G$ over an integral domain $R$ with $1$. As an application we extend a well known result on derivation of an integral group ring $\Bbb{Z}G$ to $(\sigma,\tau)$derivation on it for a finite group $G$ with some conditions on $\sigma$ and $\tau$. In the process of the extension, a generalization of an application of SkolemNoether Theorem to derivation on a finite dimensional central simple algebra has also been given for the $(\sigma,\tau)$derivation case.
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The $P$partition generating function of a (naturally labeled) poset $P$ is a quasisymmetric function enumerating orderpreserving maps from $P$ to $\mathbb{Z}^+$. Using the Hopf algebra of posets, we give necessary conditions for two posets to have the same generating function. In particular, we show that they must have the same number of antichains of each size, as well as the same shape (as defined by Greene). We also discuss which shapes guarantee uniqueness of the $P$partition generating function and give a method of constructing pairs of nonisomorphic posets with the same generating function.
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Reduced Rank Extrapolation (RRE) is a polynomial type method used to accelerate the convergence of sequences of vectors $\{\xx_m\}$. It is applied successfully in different disciplines of science and engineering in the solution of large and sparse systems of linear and nonlinear equations of very large dimension. If $\sss$ is the solution to the system of equations $\xx=\ff(\xx)$, first, a vector sequence $\{\xx_m\}$ is generated via the fixedpoint iterative scheme $\xx_{m+1}=\ff(\xx_m)$, $m=0,1,\ldots,$ and next, RRE is applied to this sequence to accelerate its convergence. RRE produces approximations $\sss_{n,k}$ to $\sss$ that are of the form $\sss_{n,k}=\sum^k_{i=0}\gamma_i\xx_{n+i}$ for some scalars $\gamma_i$ depending (nonlinearly) on $\xx_n, \xx_{n+1},\ldots,\xx_{n+k+1}$ and satisfying $\sum^k_{i=0}\gamma_i=1$. The convergence properties of RRE when applied in conjunction with linear $\ff(\xx)$ have been analyzed in different publications. In this work, we discuss the converg
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We devise and evaluate numerically a Hybrid HighOrder (HHO) method for incremental associative plasticity with small deformations. The HHO method uses as discrete unknowns piecewise polynomials of order $k\ge1$ on the mesh skeleton, together with cellbased polynomials that can be eliminated locally by static condensation. The HHO method supports polyhedral meshes with nonmatching interfaces, is free of volumetriclocking and the integration of the behavior law is performed only at cellbased quadrature nodes. Moreover, the principle of virtual work is satisfied locally with equilibrated tractions. Various two and threedimensional test cases from the literature are presented including comparison against known solutions and against results obtained with an industrial software using conforming and mixed finite elements.
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Neural network decoding algorithms are recently introduced by Nachmani et al. to decode highdensity paritycheck (HDPC) codes. In contrast with iterative decoding algorithms such as sumproduct or minsum algorithms in which the weight of each edge is set to $1$, in the neural network decoding algorithms, the weight of every edge depends on its impact in the transmitted codeword. In this paper, we provide a novel \emph{feedforward neural network lattice decoding algorithm} suitable to decode lattices constructed based on Construction A, whose underlying codes have HDPC matrices. We first establish the concept of feedforward neural network for HDPC codes and improve their decoding algorithms compared to Nachmani et al. We then apply our proposed decoder for a Construction A lattice with HDPC underlying code, for which the wellknown iterative decoding algorithms show poor performances. The main advantage of our proposed algorithm is that instead of assigning and training weights for
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For source sequences of length L symbols we proposed to use a more realistic value to the usual benchmark of number of code letters by source letters. Our idea is based on a quantifier of information fluctuation of a source, F(U), which corresponds to the second central moment of the random variable that measures the information content of a source symbol. An alternative interpretation of typical sequences is additionally provided through this approach.
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A posteriori error analysis is a technique to quantify the error in particular simulations of a numerical approximation method. In this article, we use such an approach to analyze how various error components propagate in certain moving boundary problems. We study quasisteady state simulations where slowly moving boundaries remain in mechanical equilibrium with a surrounding fluid. Such problems can be numerically approximated with the Method of Regularized Stokelets(MRS), a popular method used for studying viscous fluidstructure interactions, especially in biological applications. Our approach to monitoring the regularization error of the MRS is novel, along with the derivation of linearized adjoint equations to the governing equations of the MRS with a elastic elements. Our main numerical results provide a clear illustration of how the error evolves over time in several MRS simulations.
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This paper considers solving convex quadratic programs (QPs) in a realtime setting using a regularized and smoothed FischerBurmeister method (FBRS). The FischerBurmeister function is used to map the optimality conditions of the quadratic program to a nonlinear system of equations which is solved using Newton's method. Regularization and smoothing are applied to improve the practical performance of the algorithm and a merit function is used to globalize convergence. FBRS is simple to code, easy to warmstart, robust to early termination, and has attractive theoretical properties, making it appealing for realtime and embedded applications. Numerical experiments using several predictive control examples show that the proposed method is competitive with other state of the art solvers.
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The columnandconstraint generation (CCG) method was introduced by \citet{Zeng2013} for solving twostage adaptive optimization. We found that the CCG method is quite scalable, but sometimes, and in some applications often, produces infeasible firststage solutions, even though the problem is feasible. In this research, we extend the CCG method in a way that (a) maintains scalability and (b) always produces feasible firststage decisions if they exist. We compare our method to several recently proposed methods and find that it reaches high accuracies faster and solves significantly larger problems.
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Bayesian optimization is an approach to optimizing objective functions that take a long time (minutes or hours) to evaluate. It is bestsuited for optimization over continuous domains of less than 20 dimensions, and tolerates stochastic noise in function evaluations. It builds a surrogate for the objective and quantifies the uncertainty in that surrogate using a Bayesian machine learning technique, Gaussian process regression, and then uses an acquisition function defined from this surrogate to decide where to sample. In this tutorial, we describe how Bayesian optimization works, including Gaussian process regression and three common acquisition functions: expected improvement, entropy search, and knowledge gradient. We then discuss more advanced techniques, including running multiple function evaluations in parallel, multifidelity and multiinformation source optimization, expensivetoevaluate constraints, random environmental conditions, multitask Bayesian optimization, and the in
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We give a combinatorial construction of an ordered semiring A, and show that it can be identified with a certain subquotient of the semiring of plocal Bousfield classes, containing almost all of the classes that have previously been named and studied. This is a convenient way to encapsulate most of the known results about Bousfield classes.
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In this article we define the first Dirichlet eigenvalue for the fractional $g$Laplacian and we prove diverse properties on it, including isolation, positivity of its eigenfunctions and its behaviour as $s\to 1^+$. In the second part of this manuscript we prove some modular and norm Hardy inequalities in fractional OrliczSobolev spaces, which provide for lower bounds of eigenvalues in certain configurations.
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We develop a general, functional calculus approach to approximation of $C_0$semigroups on Banach spaces by bounded completely monotone functions of their generators. The approach comprises most of wellknown approximation formulas, yields optimal convergence rates, and sometimes even leads to sharp constants. In an important particular case when semigroups are holomorphic, we are able to significantly improve our results for general semigroups. Moreover, we present several second order approximation formulas with rates, which in such a general form appear in the literature for the first time.
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We study stochastic Amaritype neural field equations, which are meanfield models for neural activity in the cortex. We prove that under certain assumptions on the coupling kernel, the neural field model can be viewed as a gradient flow in a nonlocal Hilbert space. This makes all gradientflow methods available for the analysis, which could previously not be used, as it was not known, whether a rigorous gradient flow formulation exists. We show that the equation is wellposed in the nonlocal Hilbert space in the sense that solutions starting in this space also remain in it for all times and spacetime regularity results hold for the case of spatially correlated noise. Uniqueness of invariant measures and ergodic properties for the associated Feller semigroups are also discussed.
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A highorder finite difference numerical scheme is developed for the ideal magnetohydrodynamic equations based on an alternative flux formulation of the weighted essentially nonoscillatory (WENO) scheme. It computes a highorder numerical flux by a Taylor expansion in space, with the lowestorder term solved from a Riemann solver and the higherorder terms constructed from physical fluxes by limited central differences. The scheme coupled with several Riemann solvers, including a LaxFriedrichs solver and HLLtype solvers, is developed on general curvilinear meshes in two dimensions and verified on a number of benchmark problems. In particular, a HLLD solver on Cartesian meshes is extended to curvilinear meshes with proper modifications. A numerical boundary condition for the perfect electrical conductor (PEC) boundary is derived for general geometry and verified through a bow shock flow. Numerical results also confirm the advantages of using low dissipative Riemann solvers in the cur
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We consider the following distributed service model: jobs with unit mean, general distribution, and independent processing times arrive as a renewal process of rate $\lambda n$, with $0<\lambda<1$, and are immediately dispatched to one of several queues associated with $n$ identical servers with unit processing rate. We assume that the dispatching decisions are made by a central dispatcher endowed with a finite memory, and with the ability to exchange messages with the servers. We study the fundamental resource requirements (memory bits and message exchange rate), in order to drive the expected queueing delay in steadystate of a typical job to zero, as $n$ increases. We develop a novel approach to show that, within a certain broad class of "symmetric" policies, every dispatching policy with a message rate of the order of $n$, and with a memory of the order of $\log n$ bits, results in an expected queueing delay which is bounded away from zero, uniformly as $n\to\infty$.
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Gunningham [G] constructed an extended topological quantum field theory (TQFT) to obtain a closed formula for all spin Hurwitz numbers. In this note, we use the gluing theorem in [LP2] to reprove the Gunningham's formula. We also describe a TQFT formalism naturally induced from the gluing theorem.
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The purpose of this note is to record a consequence, for general metric spaces, of a recent result of David Bate. We prove the following fact: Let $X$ be a compact metric space of topological dimension $n$. Suppose that the $n$dimensional Hausdorff measure of $X$, $\mathcal H^n(X)$, is finite. Suppose further that the lower ndensity of the measure $\mathcal H^n$ is positive, $\mathcal H^n$almost everywhere in $X$. Then $X$ contains an $n$rectifiable subset of positive $\mathcal H^n$measure. Moreover, the assumption on the lower density is unnecessary if one uses recently announced results of Cs\"ornyeiJones.
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A perturbational vector duality approach for objective functions $f\colon X\to \bar{L}^0$ is developed, where $X$ is a Banach space and $\bar{L}^0$ is the space of extended real valued functions on a measure space, which extends the perturbational approach from the scalar case. The corresponding strong duality statement is proved under a closedness type regularity condition. Optimality conditions and a MoreauRockafellar type formula are provided. The results are specialized for constrained and unconstrained problems. Examples of integral operators and risk measures are discussed.
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