Hybrid implementation of the fastICA algorithm for high-density EEG using the capabilities of the Intel architecture and CUDA programming

High-density electroencephalographic (EEG) systems are utilized in the study of the human brain and its underlying behaviors. However, working with EEG data requires a well-cleaned signal, which is often achieved through the use of independent component analysis (ICA) methods. The calculation time for these types of algorithms is the longer the more data we have. This article presents a hybrid implementation of the fastICA algorithm that uses parallel programming techniques (libraries and extensions of the Intel processors and CUDA programming), which results in a significant acceleration of execution time on selected architectures

New Results on Fair Multi-threaded Paging

The Multi-threaded Paging problem (MTP) was introduced as a generalization of Paging for the case where there are many threads of requests. This models situations in which the requests come from more than one independent source. At each step it is necessary to decide which request to serve among several possibilities, and also (as in normal Paging) which page of fast memory to remove on a page fault. In the fair version of the problem any algorithm must guarantee that the next request of each thread will be served within a predetermined finite time.In this paper we reduce the existing gaps between the known lower and upper bounds for the competitiveness of on-line algorithms for the fair version of MTP. We treat some particular situations, with finite and infinite input sequences. We prove higher lower bounds and present a new on-line algorithm. We close the gap for the case in which the cache can hold only one page; surprisingly, we obtain different bounds for even and odd number of sequences; we prove that any lazy algorithm achieves the on-line lower bound when the number of sequences is odd.Research supported in part by EC project DYNDATA under program KIT, and by UBACyT projects ``Algoritmos Eficientes para Problemas On-line con Aplicaciones'' and ``Modelos y Técnicas de Optimización Combinatoria".Sociedad Argentina de Informática e Investigación Operativ

Assessment of the Versatility of Virtual Orchestra Technology as a Rehearsal Tool

This is an assessment of the versatility of Sinfonia virtual orchestra technology for use in a technological rehearsal environment in music education

Validation and clinical implementation of an accurate Monte Carlo code for pencil beam scanning proton therapy.

Monte Carlo (MC)-based dose calculations are generally superior to analytical dose calculations (ADC) in modeling the dose distribution for proton pencil beam scanning (PBS) treatments. The purpose of this paper is to present a methodology for commissioning and validating an accurate MC code for PBS utilizing a parameterized source model, including an implementation of a range shifter, that can independently check the ADC in commercial treatment planning system (TPS) and fast Monte Carlo dose calculation in opensource platform (MCsquare). The source model parameters (including beam size, angular divergence and energy spread) and protons per MU were extracted and tuned at the nozzle exit by comparing Tool for Particle Simulation (TOPAS) simulations with a series of commissioning measurements using scintillation screen/CCD camera detector and ionization chambers. The range shifter was simulated as an independent object with geometric and material information. The MC calculation platform was validated through comprehensive measurements of single spots, field size factors (FSF) and three-dimensional dose distributions of spread-out Bragg peaks (SOBPs), both without and with the range shifter. Differences in field size factors and absolute output at various depths of SOBPs between measurement and simulation were within 2.2%, with and without a range shifter, indicating an accurate source model. TOPAS was also validated against anthropomorphic lung phantom measurements. Comparison of dose distributions and DVHs for representative liver and lung cases between independent MC and analytical dose calculations from a commercial TPS further highlights the limitations of the ADC in situations of highly heterogeneous geometries. The fast MC platform has been implemented within our clinical practice to provide additional independent dose validation/QA of the commercial ADC for patient plans. Using the independent MC, we can more efficiently commission ADC by reducing the amount of measured data required for low dose "halo" modeling, especially when a range shifter is employed

ARTICLE NO. PC971367 A Library-Based Approach to Task Parallelism in a Data-Parallel Language

Pure data-parallel languages such as High Performance Fortran version 1 (HPF) do not allow efficient expression of mixed task/data-parallel computations or the coupling of separately compiled data-parallel modules. In this paper, we show how these common parallel program structures can be represented, with only minor extensions to the HPF model, by using a coordination library based on the Message Passing Interface (MPI). This library allows data-parallel tasks to exchange distributed data structures using calls to simple communication functions. We present microbenchmark results that characterize the performance of this library and that quantify the impact of optimizations that allow reuse of communication schedules in common situations. In addition, results from two-dimensional FFT, convolution, and multiblock programs demonstrate that the HPF/ MPI library can provide performance superior to that of pure HPF. We conclude that this synergistic combination of two parallel programming standards represents a useful approach to task parallelism in a data-parallel framework, increasing the range of problems addressable in HPF without requiring complex compile

Vyacheslav V. Ivanov (1929–2017) and his Studies in Prosody and Poetics

Vyacheslav V. Ivanov was an outstanding scholar who excelled in almost all disciplines related to linguistic and literary studies. This article analyses his accomplishments in the fields of prosody and poetics

The Erd\H{o}s--Moser equation 1k+2k+...+(m−1)k=mk1^k+2^k+...+(m-1)^k=m^k revisited using continued fractions

If the equation of the title has an integer solution with $k\ge2$, then $m>10^{9.3\cdot10^6}$. This was the current best result and proved using a method due to L. Moser (1953). This approach cannot be improved to reach the benchmark $m>10^{10^7}$. Here we achieve $m>10^{10^9}$ by showing that $2k/(2m-3)$ is a convergent of $\log2$ and making an extensive continued fraction digits calculation of $(\log2)/N$, with $N$ an appropriate integer. This method is very different from that of Moser. Indeed, our result seems to give one of very few instances where a large scale computation of a numerical constant has an application.Comment: 17 page