445 research outputs found

    A generalization of Margolus-Levitin bound

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    The Margolus-Levitin lower bound on minimal time required for a state to be transformed into an orthogonal state is generalized. It is shown that for some initial states new bound is stronger than the Margolus-Levitin one.Comment: 6 pages, no figures; some comments added; final version accepted for publication in Phys. Rev.

    Automatic Adaptation of SOA Systems Supported by Machine Learning

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    Part 3: Service OrientationInternational audienceRecent advances in the development of information systems have led to increased complexity and cost in terms of the required maintenance and management. On the other hand, systems built in accordance with modern architectural paradigms, such as Service Oriented Architecture (SOA), posses features enabling extensive adaptation, not present in traditional systems. Automatic adaptation mechanisms can be used to facilitate system management. The goal of this work is to show that automatic adaptation can be effectively implemented in SOA systems using machine learning algorithms. The presented concept relies on a combination of clustering and reinforcement learning algorithms. The paper discusses assumptions which are necessary to apply machine learning algorithms to automatic adaptation of SOA systems, and presents a machine learning-based management framework prototype. Possible benefits and disadvantages of the presented approach are discussed and the approach itself is validated with a representative case study

    Adapting a HEP Application for Running on the Grid

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    The goal of the EU IST int.eu.grid project is to build middleware facilities which enable the execution of real-time and interactive applications on the Grid. Within this research, relevant support for the HEP application is provided by Virtual Organization, monitoring system, and real-time dispatcher (RTD). These facilities realize the pilot jobs idea that allows to allocate grid resources in advance and to analyze events in real time. In the paper we present HEP Virtual Organization, the details of monitoring, and RTD. We present the way of running the HEP application using the above facilities to fit into the real-time application requirements

    Measurement of the invariant mass distributions for the pp -> ppeta' reaction at excess energy of Q = 16.4 MeV

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    The proton-proton and proton-eta' invariant mass distributions have been determined for the pp -> ppeta' reaction at an excess energy of Q = 16.4 MeV. The measurement was carried out using the COSY-11 detector setup and the proton beam of the cooler synchrotron COSY. The shapes of the determined invariant mass distributions are similar to those of the pp -> ppeta reaction and reveal an enhancement for large relative proton-proton momenta. This result, together with the fact that the proton-eta interaction is much stronger that the proton-eta' interaction, excludes the hypothesis that the observed enhancement is caused by the interaction between the proton and the meson

    System Response Kernel Calculation for List-mode Reconstruction in Strip PET Detector

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    Reconstruction of the image in Positron Emission Tomographs (PET) requires the knowledge of the system response kernel which describes the contribution of each pixel (voxel) to each tube of response (TOR). This is especially important in list-mode reconstruction systems, where an efficient analytical approximation of such function is required. In this contribution, we present a derivation of the system response kernel for a novel 2D strip PET.Comment: 10 pages, 2 figures; Presented at Symposium on applied nuclear physics and innovative technologies, Cracow, 03-06 June 201

    Analysis framework for the J-PET scanner

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    J-PET analysis framework is a flexible, lightweight, ROOT-based software package which provides the tools to develop reconstruction and calibration procedures for PET tomography. In this article we present the implementation of the full data-processing chain in the J-PET framework which is used for the data analysis of the J-PET tomography scanner. The Framework incorporates automated handling of PET setup parameters' database as well as high level tools for building data reconstruction procedures. Each of these components is briefly discussed.Comment: 6 pages, 1 figur

    Hit time and hit position reconstruction in the J-PET detector based on a library of averaged model signals

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    In this article we present a novel method of hit time and hit position reconstruction in long scintillator detectors. We take advantage of the fact that for this kind of detectors amplitude and shape of registered signals depends strongly on the position where particle hit the detector. The reconstruction is based on determination of the degree of similarity between measured and averaged signals stored in a library for a set of well-defined positions along the scintillator. Preliminary results of validation of the introduced method with experimental data obtained by means of the double strip prototype of the J-PET detector are presented

    Beam profile investigation of the new collimator system for the J-PET detector

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    Jagiellonian Positron Emission Tomograph (J-PET) is a multi-purpose detector which will be used for search for discrete symmetries violations in the decays of positronium atoms and for investigations with positronium atoms in life-sciences and medical diagnostics. In this article we present three methods for determination of the beam profile of collimated annihilation gamma quanta. Precise monitoring of this profile is essential for time and energy calibration of the J-PET detector and for the determination of the library of model signals used in the hit-time and hit-position reconstruction. We have we have shown that usage of two lead bricks with dimensions of 5x10x20 cm^3 enables to form a beam of annihilation quanta with Gaussian profile characterized by 1 mm FWHM. Determination of this characteristic is essential for designing and construction the collimator system for the 24-module J-PET prototype. Simulations of the beam profile for different collimator dimensions were performed. This allowed us to choose optimal collimation system in terms of the beam profile parameters, dimensions and weight of the collimator taking into account the design of the 24 module J-PET detector.Comment: 14 pages, 9 figure

    Application of Compressive Sensing Theory for the Reconstruction of Signals in Plastic Scintillators

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    Compressive Sensing theory says that it is possible to reconstruct a measured signal if an enough sparse representation of this signal exists in comparison to the number of random measurements. This theory was applied to reconstruct signals from measurements of plastic scintillators. Sparse representation of obtained signals was found using SVD transform.Comment: 7 pages, 3 figures; Presented at Symposium on applied nuclear physics and innovative technologies, Cracow, 03-06 June 201
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