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Search Results: 1 - 10 of 84713 matches for " W. Wi?licki "
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Polarization of Valence and Sea Quarks in the Proton
Wojciech Wilicki
Physics , 1994,
Abstract: Analysis was performed of semi-inclusive and inclusive spin asymmetries determined from the polarized deep inelastic scattering by the Spin Muon Collaboration. Combined analysis of data for polarized deuterium and hydrogen targets allows for separate determination of spin carried by valence {\it u} and {\it d} quarks and non-strange sea quarks as a function of $x_{Bj}$ in the range $0.006
Grand canonical minority game as a sign predictor
Karol Wawrzyniak,Wojciech Wilicki
Quantitative Finance , 2013,
Abstract: In this paper the extended model of Minority game (MG), incorporating variable number of agents and therefore called Grand Canonical, is used for prediction. We proved that the best MG-based predictor is constituted by a tremendously degenerated system, when only one agent is involved. The prediction is the most efficient if the agent is equipped with all strategies from the Full Strategy Space. Each of these filters is evaluated and, in each step, the best one is chosen. Despite the casual simplicity of the method its usefulness is invaluable in many cases including real problems. The significant power of the method lies in its ability to fast adaptation if \lambda-GCMG modification is used. The success rate of prediction is sensitive to the properly set memory length. We considered the feasibility of prediction for the Minority and Majority games. These two games are driven by different dynamics when self-generated time series are considered. Both dynamics tend to be the same when a feedback effect is removed and an exogenous signal is applied.
System Response Kernel Calculation for List-mode Reconstruction in Strip PET Detector
P. Bia?as,J. Kowal,A. Strzelecki,T. Bednarski,E. Czerwiński,?. Kap?on,A. Kochanowski,G. Korcyl,P. Kowalski,T. Kozik,W. Krzemień,M. Molenda,P. Moskal,Sz. Nied?wiecki,M. Pa?ka,M. Pawlik,L. Raczyński,Z. Rudy,P. Salabura,N. G. Sharma,M. Silarski,A. S?omski,J. Smyrski,W. Wilicki,M. Zieliński
Physics , 2013, DOI: 10.5506/APhysPolBSupp.6.1027
Abstract: 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.
Application of Compressive Sensing Theory for the Reconstruction of Signals in Plastic Scintillators
L. Raczyński,P. Kowalski,T. Bednarski,P. Bia?as,E. Czerwiński,?. Kap?on,A. Kochanowski,G. Korcyl,J. Kowal,T. Kozik,W. Krzemień,M. Molenda,P. Moskal,Sz. Nied?wiecki,M. Pa?ka,M. Pawlik,Z. Rudy,P. Salabura,N. G. Sharma,M. Silarski,A. S?omski,J. Smyrski,A. Strzelecki,W. Wilicki,M. Zieliński
Physics , 2013, DOI: 10.5506/APhysPolBSupp.6.1121
Abstract: 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.
Computing support for advanced medical data analysis and imaging
W. Wilicki,T. Bednarski,P. Bia?as,E. Czerwiński,?. Kap?on,A. Kochanowski,G. Korcyl,J. Kowal,P. Kowalski,T. Kozik,W. Krzemień,M. Molenda,P. Moskal,S. Nied?wiecki,M. Pa?ka,M. Pawlik,L. Raczyński,Z. Rudy,P. Salabura,N. G. Sharma,M. Silarski,A. S?omski,J. Smyrski,A. Strzelecki,A. Wieczorek,M. Zieliński,N. Zoń
Physics , 2014, DOI: 10.1515/bams-2014-0001
Abstract: We discuss computing issues for data analysis and image reconstruction of PET-TOF medical scanner or other medical scanning devices producing large volumes of data. Service architecture based on the grid and cloud concepts for distributed processing is proposed and critically discussed.
Database and data structure for the novel TOF-PET detector developed for J-PET project
E. Czerwiński,M. Zieliński,T. Bednarski,P. Bia?as,?. Kap?on,A. Kochanowski,G. Korcyl,J. Kowal,P. Kowalski,T. Kozik,W. Krzemień,E. Kubicz,M. Molenda,P. Moskal,Sz. Nied?wiecki,M. Pa?ka,M. Pawlik,L. Raczyński,Z. Rudy,P. Salabura,N. G. Sharma,M. Silarski,A. S?omski,J. Smyrski,A. Strzelecki,A. Wieczorek,W. Wilicki,N. Zoń
Physics , 2014, DOI: 10.1515/bams-2014-0003
Abstract: The complexity of the hardware and the amount of data collected during the PET imaging process require application of modern methods of efficient data organization and processing. In this article we will discuss the data structures and the flow of collected data from the novel TOF-PET medical scanner which is being developed at the Jagiellonian University. The developed data format reflects: registration process of the gamma quanta emitted from positron-electron annihilation, Front-End Electronic (FEE) structure and required input information for the image reconstruction. In addition, the system database fulfills possible demands of the evolving J-PET project.
A novel method for calibration and monitoring of time synchronization of TOF-PET scanners by means of cosmic rays
M. Silarski,E. Czerwiński,T. Bednarski,P. Moskal,P. Bia?as,?. Kap?on,A. Kochanowski,G. Korcyl,J. Kowal,P. Kowalski,T. Kozik,W. Krzemień,M. Molenda,Sz. Nied?wiecki,M. Pa?ka,M. Pawlik,L. Raczyński,Z. Rudy,P. Salabura,N. G. Sharma,A. S?omski,J. Smyrski,A. Strzelecki,W. Wilicki,M. Zieliński,N. Zoń
Physics , 2013, DOI: 10.1515/bams-2013-0105
Abstract: All of the present methods for calibration and monitoring of TOF-PET scanner detectors utilize radioactive isotopes such as e.g. $^{22}$Na or $^{68}$Ge, which are placed or rotate inside the scanner. In this article we describe a novel method based on the cosmic rays application to the PET calibration and monitoring methods. The concept allows to overcome many of the drawbacks of the present methods and it is well suited for newly developed TOF-PET scanners with a large longitudinal field of view. The method enables also monitoring of the quality of the scintillator materials and in general allows for the continuous quality assurance of the PET detector performance.
A novel method based solely on FPGA units enabling measurement of time and charge of analog signals in Positron Emission Tomography
M. Pa?ka,T. Bednarski,P. Bia?as,E. Czerwiński,?. Kap?on,A. Kochanowski,G. Korcyl,J. Kowal,P. Kowalski,T. Kozik,W. Krzemień,M. Molenda,P. Moskal,Sz. Nied?wiecki,M. Pawlik,L. Raczyński,Z. Rudy,P. Salabura,N. G. Sharma,M. Silarski,A. S?omski,J. Smyrski,A. Strzelecki,W. Wilicki,M. Zieliński,N. Zoń
Physics , 2013, DOI: 10.1515/bams-2013-0104
Abstract: This article presents a novel technique for precise measurement of time and charge based solely on FPGA (Field Programmable Gate Array) device and few satellite discrete electronic components used in Positron Emission Tomography (PET). Described approach simplifies electronic circuits, reduces the power consumption, lowers costs, merges front-end electronics with digital electronics and also makes more compact final design. Furthermore, it allows to measure time when analog signals cross a reference voltage at different threshold levels with a very high precision of $\sim$ 10ps (rms) and thus enables sampling of signals in a voltage domain.
Application of WLS strips for position determination in Strip PET tomograph based on plastic scintillators
J. Smyrski,P. Moskal,T. Bednarski,P. Bia?as,E. Czerwiński,?. Kap?on,A. Kochanowski,G. Korcyl,J. Kowal,P. Kowalski,T. Kozik,W. Krzemień,M. Molenda,Sz. Nied?wiecki,M. Pa?ka,M. Pawlik,L. Raczyński,Z. Rudy,P. Salabura,N. G. Sharma,M. Silarski,A. S?omski,A. Strzelecki,W. Wilicki,M. Zieliński,N. Zoń
Physics , 2013, DOI: 10.1515/bams-2013-0103
Abstract: A method of determination of a gamma quantum absorption point in a plastic scintillator block using a matrix of wavelength-shifting (WLS) strips is proposed. Application of this method for improvement of position resolution in newly proposed PET detectors based on plastic scintillators is presented. The method enables to reduce parallax errors in reconstruction of images which occurs in the presently used Positron Emission Tomography scanners.
J-PET analysis framework for the prototype TOF-PET detector
W. Krzemień,M. Silarski,K. Stola,D. Trybek,T. Bednarski,P. Bia?as,E. Czerwiński,?. Kap?on,A. Kochanowski,G. Korcyl,J. Kowal,P. Kowalski,T. Kozik,M. Molenda,P. Moskal,Sz. Nied?wiecki,M. Pa?ka,M. Pawlik,L. Raczyński,Z. Rudy,P. Salabura,N. G. Sharma,A. S?omski,J. Smyrski,A. Strzelecki,W. Wilicki,M. Zieliński,N. Zoń
Physics , 2013, DOI: 10.1515/bams-2013-0109
Abstract: Novel TOF-PET scanner solutions demand, apart from the state of the art detectors, software for fast processing of the gathered data, monitoring of the whole scanner and reconstruction of the PET image. In this article we present an analysis framework for the novel STRIP-PET scanner developed by the J-PET collaboration in the Institute of Physics of the Jagiellonian University. This software is based on the ROOT package used in many particle physics experiments.
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