We present on-line algorithms for computing approximations of rank-based statistics that give high accuracy, particularly near the tails a distribution, with very small sketches. Notably, method allows quantile $q$ to be computed an accuracy relative $\max(q, 1-q)$ rather than absolute as most other methods. This new algorithm is robust respect skewed distributions or ordered datasets and separately summaries combined no loss in accuracy. An open-source Java implementation this available...

We report recording simulations on graded media with area densities of 1Tbit∕in.2. The are composed a nucleation layer exchange coupled to hard magnetic storage layer. has an anisotropy K(z) that gradually varies in order adjust the domain wall propagation field write field. Bits were written bit length 12nm and track width 53nm total thickness 21nm maximum 1MJ∕m3. computed values for transition jitter around 0.65nm, depending intergrain exchange.

The probability Jaccard similarity was recently proposed as a natural generalization of the to measure proximity sets whose elements are associated with relative frequencies or probabilities. In combination hash algorithm that maps those weighted compact signatures which allow fast estimation pairwise similarities, it constitutes valuable method for big data applications such near-duplicate detection, nearest neighbor search, clustering. This paper introduces class one-pass...

Distributed stream processing frameworks help building scalable and reliable applications that perform transformations aggregations on continuous data streams. This paper introduces ShuffleBench, a novel benchmark to evaluate the performance of modern frameworks. In contrast other benchmarks, it focuses use cases where are mainly employed for shuffling (i.e., re-distributing) records state-local aggregations, while actual aggregation logic is considered as black-box software components....

Detailed studies of the structure magnetic nanoclusters are crucial for understanding their properties. We have investigated CoxAg1−x nanoparticles by means molecular dynamics simulations utilizing embedded atom method. Starting from a completely random distribution Co and Ag atoms, clusters were heated up to 1300K subsequently cooled down. The size resulting particles was 2.8nm (864 atoms). A clear segregation atoms on surface core obtained.

We perform multiscale finite element simulation of the write process in perpendicular media. The Landau-Lifshitz-Gilbert equation is solved simultaneously for head, data layer, and soft under layer during motion head. All magnetostatic interactions between underlayer are concurrently taken into account. This fully integrated recording model enables a detailed analysis head field as seen by media grains.

MinHash and HyperLogLog are sketching algorithms that have become indispensable for set summaries in big data applications. While allows counting different elements with very little space, is suitable the fast comparison of sets as it estimating Jaccard similarity other joint quantities. This work presents a new structure called SetSketch able to continuously fill gap between both use cases. Its commutative idempotent insert operation its mergeable state make distributed environments. Fast,...

Since its invention HyperLogLog has become the standard algorithm for approximate distinct counting. Due to space efficiency and suitability distributed systems, it is widely used also implemented in numerous databases. This work presents UltraLogLog, which shares same practical properties as HyperLogLog. It commutative, idempotent, mergeable, a fast guaranteed constant-time insert operation. At time, requires 28% less encode amount of count information, can be extracted using maximum...

Exchange spring media are proposed for magnetic-recording systems consisting of a hard/soft bilayer. By varying the fraction thickness hard and soft layer by their saturation polarizations, properties can be optimized in order to achieve high thermal stability without increase coercive field. In grains with identical size coercivity, an bilayer reaches energy barrier exceeding those single-phase more than factor two. Thus, exchange allow reduce grain diameter 1//spl radic/2. Additionally,...

We developed a micromagnetic eddy current method that allows arbitrary geometries, requires no mesh outside the ferromagnet, and uses stable integration scheme. simultaneously solve Landau–Lifshitz–Gilbert equation quasistatic Maxwell equations using hybrid finite element/boundary element (FEM/BEM). The field is directly calculated from space time behavior of magnetization rate change. boundary conditions at infinity are taken into account FEM/BEM resulting system differential algebraic...

Several software systems are built upon stream processing architectures to process large amounts of data in near real-time. Today's distributed (DSPSs) spread the among multiple machines provide scalable performance. However, high-performance and Quality Service (QoS) challenging predict, achieve, maintain. While many studies focus on evaluating or improving performance processing, getting a comprehensive view current state DSPSs their real-world deployments is challenging. In this paper, we...

Minwise hashing has become a standard tool to calculate signatures which allow direct estimation of Jaccard similarities. While very efficient algorithms already exist for the unweighted case, calculation weighted sets is still time consuming task. BagMinHash new algorithm that can be orders magnitude faster than current state art without any particular restrictions or assumptions on weights data dimensionality. Applied special case sets, it represents first producing independent signature...

This paper presents new methods to estimate the cardinalities of data sets recorded by HyperLogLog sketches. A theoretically motivated extension original estimator is presented that eliminates bias for small and large cardinalities. Based on maximum likelihood principle a second unbiased method derived together with robust efficient numerical algorithm calculate estimate. The approach can also be applied more than single sketch. In particular, it shown gives precise cardinality estimates...

This paper presents a new algorithm for calculating hash signatures of sets which can be directly used Jaccard similarity estimation. The approach is an improvement over the MinHash algorithm, because it has better runtime behavior and resulting allow more precise estimation index.

Nowadays, several software systems rely on stream processing architectures to deliver scalable performance and handle large volumes of data in near real-time. Stream frameworks facilitate computing by distributing the application's execution across multiple machines. Despite being extensively studied, measurement fault tolerance-a key feature offered frameworks-has still not been measured properly with updated comprehensive testbeds. Moreover, impact that recovery can have is mostly ignored....

In this paper, we determine the critical particle size and conductivity range that leads to pronounced eddy current effects on magnetization reversal of magnetic nanostructures. An extended finite-element micromagnetic solver which includes currents is used calculate behavior a permalloy nanocube 27 nm side under influence an applied field. It shown for high-conductivity /spl sigma/>10/sup 6/ (/spl Omega/ m)/sup -1/ in intermediate state it takes longer fully align direction

The Landau-Lifshitz-Gilbert equation and quasistatic Maxwell equations were solved simultaneously to calculate the read back signal of giant magnetoresistance heads with a hybrid finite-element/boundary element method. finite-element simulations show influence sense current on linearity reader, effect exchange bias field sensor performance, Gilbert damping constant decay time voltage. All parts system, layers sensor, hard magnets, shields, recording layer are treated micromagnetically. In...

Vortex nucleation and vortex motion are the main mechanisms of magnetization reversal in micrometer-sized magnetic elements. The critical field required to nucleate a depends on temperature. We propose method that combines standard Landau-Lifshitz-Gilbert (LLG) micromagnetics an elastic band simulate nonzero temperature hysteresis curves thin film Whereas LLG simulations gives equilibriums states before after enters element, height energy barrier between these two states. Thus...

Dynamic effects are studied in a perpendicular write head for different magnetic anisotropies by multigrid dynamic micromagnetic simulations. We show that there is an intrinsic time-scale (of order 500-750 ps) of the interacting system head/data layer/soft underlayer gating speed flux-rise media as well rate decay flux. In particular, turnoff depends strongly on anisotropy.

We present new techniques for three-dimensional topography simulation of processes which ballistic transport can be assumed at feature-scale. The combination algorithms and data structures lent from the area computer graphics allows a fast memory saving solution various deposition etching processes.