Resonant cyclotron acceleration of particles by a time periodic singular flux tube

We study the dynamics of a classical nonrelativistic charged particle moving on a punctured plane under the influence of a homogeneous magnetic field and driven by a periodically time-dependent singular flux tube through the hole. We observe an effect of resonance of the flux and cyclotron frequencies. The particle is accelerated to arbitrarily high energies even by a flux of small field strength which is not necessarily encircled by the cyclotron orbit; the cyclotron orbits blow up and the particle oscillates between the hole and infinity. We support this observation by an analytic study of an approximation for small amplitudes of the flux which is obtained with the aid of averaging methods. This way we derive asymptotic formulas that are afterwards shown to represent a good description of the accelerated motion even for fluxes which are not necessarily small. More precisely, we argue that the leading asymptotic terms may be regarded as approximate solutions of the original system in the asymptotic domain as the time tends to infinity

GraphMineSuite: Enabling High-Performance and Programmable Graph Mining Algorithms with Set Algebra

We propose GraphMineSuite (GMS): the first benchmarking suite for graph mining that facilitates evaluating and constructing high-performance graph mining algorithms. First, GMS comes with a benchmark specification based on extensive literature review, prescribing representative problems, algorithms, and datasets. Second, GMS offers a carefully designed software platform for seamless testing of different fine-grained elements of graph mining algorithms, such as graph representations or algorithm subroutines. The platform includes parallel implementations of more than 40 considered baselines, and it facilitates developing complex and fast mining algorithms. High modularity is possible by harnessing set algebra operations such as set intersection and difference, which enables breaking complex graph mining algorithms into simple building blocks that can be separately experimented with. GMS is supported with a broad concurrency analysis for portability in performance insights, and a novel performance metric to assess the throughput of graph mining algorithms, enabling more insightful evaluation. As use cases, we harness GMS to rapidly redesign and accelerate state-of-the-art baselines of core graph mining problems: degeneracy reordering (by up to >2x), maximal clique listing (by up to >9x), k-clique listing (by 1.1x), and subgraph isomorphism (by up to 2.5x), also obtaining better theoretical performance bounds

Implementace a evaluace protokolu CBOR

CBOR (RFC 7049) is a recent binary schema-less data serialization protocol similar to JSON and BSON. It introduces several novel concepts, such as explicit streaming support and extensible semantics. A robust, generic, standard-compliant implementation for C is developed and presented, along with its binding for the Ruby language. Both the implementation and the protocol itself are critically evaluated by both experimental and theoretical inquiries. The measurements show that the implementation achieves performance superior to relevant alternatives while still providing a rich set of features. CBOR offers functionality and efficiency on par with or superior to the alternatives. Both high- volume applications and constrained node systems might benefit from CBOR. Some of its features, however, were shown to be needlessly complex or impractical. Suggestions addressing these deficiencies are presented. Several other approaches to implementing CBOR are proposed and discussed. Powered by TCPDF (www.tcpdf.org

Fiber Optic Sensor of Ammonia Gas Using Plasmonic Extraordinary Optical Transmission

While standard surface plasmon resonance (bio) sensing, relaying on propagating surface plasmon polariton sensitivity on homogeneous metal/dielectric boundaries, represents nowadays a routine sensing technique, other alternatives, such as inverse designs with nanostructured plasmonic periodic hole arrays, have been far less studied, especially in the context of gas sensing applications. Here, we present a specific application of such a plasmonic nanostructured array for ammonia gas sensing, based on a combination of fiber optics, extraordinary optical transmission (EOT) effect, and chemo-optical transducer selectively sensitive to ammonia gas. The nanostructured array of holes is drilled in a thin plasmonic gold layer by means of focused ion beam technique. The structure is covered by chemo-optical transducer layer showing selective spectral sensitivity towards gaseous ammonia. Metallic complex of 5-(4′-dialkylamino-phenylimino)-quinoline-8-one dye soaked in polydimethylsiloxane (PDMS) matrix is used in place of the transducer. Spectral transmission of the resulting structure and its changes under exposition to ammonia gas of various concentrations is then interrogated by fiber optics tools. The observed VIS-NIR EOT spectra are juxtaposed to the predictions performed by the rigorous Fourier modal method (FMM), providing useful theoretical feedback to the experimental data, and ammonia gas sensing mechanism of the whole EOT system and its parameters are discussed