TY - JOUR A1 - Wedrowski, M. A1 - Bruyndonckx, P. A1 - Tavernier, S. A1 - Zhi, L. A1 - Dang, J. A1 - Mendes, P. R. A1 - Perez, J. M. A1 - Ziemons, Karl T1 - Robustness of neural networks algorithm for gamma detection in monolithic block detector, positron emission tomography JF - 2009 IEEE Nuclear Science Symposium Conference Record (NSS/MIC) N2 - The monolithic scintillator block approach for gamma detection in the Positron Emission Tomography (PET) avoids estimating Depth of Interaction (DOI), reduces dead zones in detector and diminishes costs of detector production. Neural Networks (NN) are very efficient to determine the entrance point of a gamma incident on a scintillator block. This paper presents results on the robustness of the spatial resolution as a function of the random fraction in the data, temperature and HV fluctuations. This is important when implementing the method in a real scanner. Measurements were done with two Hamamatsu S8550 APD arrays, glued on a 20 × 20 × 10 mm3 monolithic LSO crystal block. Y1 - 2009 SN - 1082-3654 SP - 2625 EP - 2628 ER - TY - JOUR A1 - Streun, M. A1 - Larue, H. A1 - Parl, C. A1 - Ziemons, Karl T1 - A compact PET detector readout using charge-to-time conversion JF - 2009 IEEE Nuclear Science Symposium Conference Record (NSS/MIC) N2 - The readout of gamma detectors is considerably simplified when the event intensity is encoded as a pulse width (Pulse Width Modulation, PWM). Time-to-Digital-Converters (TDC) replace the conventional ADCs and multiple TDCs can be realized easily in one PLD chip (Programmable Logic Device). The output of a PWM stage is only one digital signal per channel which is well suited for transport so that further processing can be performed apart from the detector. This is particularly interesting for large systems with high channel density (e.g. high resolution scanners). In this work we present a circuit with a linear transfer function that requires a minimum of components by performing the PWM already in the preamp stage. This allows a very compact and also cost-efficient implementation of the front-end electronics. Y1 - 2009 SN - 1082-3654 SP - 1868 EP - 1870 PB - IEEE CY - New York ER - TY - JOUR A1 - Kotliar, Konstantin A1 - Kharoubi, A. A1 - Schmidt-Trucksäß, A. A1 - Halle, M. A1 - Lanzl, I. T1 - Does internal longitudinal microstructure of retinal veins change with age in medically healthy persons? JF - Acta Ophthalmologica Y1 - 2009 SN - 1600-0420 (E-Journal); 1755-3768 (E-Journal); 0001-639X (Print); 1395-3907 (Print); 1755-375X (Print) VL - Vol. 87 IS - Suppl. S244 SP - 0 PB - Wiley CY - Weinheim ER - TY - JOUR A1 - Arampatzis, Adamantios A1 - Karamanidis, Kiros A1 - Mademli, Lida A1 - Albracht, Kirsten T1 - Plasticity of the human tendon to short and long-term mechanical loading JF - Exercise and Sport Sciences Reviews Y1 - 2009 U6 - http://dx.doi.org/10.1097/JES.0b013e31819c2e1d SN - 1538-3008 VL - 37 IS - 2 SP - 66 EP - 72 ER - TY - JOUR A1 - Lehnertz, Klaus A1 - Bialonski, Stephan A1 - Horstmann, Marie-Therese A1 - Krug, Dieter A1 - Rothkegel, Alexander A1 - Staniek, Matthäus A1 - Wagner, Tobias T1 - Synchronization phenomena in human epileptic brain networks JF - Journal of neuroscience methods Y1 - 2009 U6 - http://dx.doi.org/10.1016/j.jneumeth.2009.05.015 SN - 0165-0270 VL - 183 IS - 1 SP - 42 EP - 48 ER - TY - JOUR A1 - Gasparyan, F. V. A1 - Poghossian, Arshak A1 - Vitusevich, S. A. A1 - Petrychuk, M. V. A1 - Sydoruk, V. A. A1 - Surmalyan, A. V. A1 - Siqueira, J. R. A1 - Oliveira, O. N. A1 - Offenhäusser, A. A1 - Schöning, Michael Josef T1 - Low Frequency Noise In Electrolyte-Gate Field-Effect Devices Functionalized With Dendrimer/Carbon-Nanotube Multilayers JF - Noise and fluctuations : 20th International Conference on Noise and Fluctuations, ICNF 2009, Pisa, Italy, 14 - 19 June 2009 / ed. Massimo Macucci; Giovanni Basso Y1 - 2009 SN - 9780735406650 N1 - AIP conference proceedings ; 1129 ; International Conference on Noise and Fluctuations ; (20, 2009, Pisa) SP - 133 EP - 136 PB - American Inst. of Physics CY - Melville, NY ER - TY - JOUR A1 - Reißel, Martin A1 - Hirschfeld, J. A. A1 - Lustfeld, H. A1 - Steffen, B. T1 - Magnetotomography and Electric Currents in a Fuel Cell / Lustfeld, H. ; Reißel, M. ; Steffen, B. JF - Fuel Cells. 9 (2009), H. 4 Y1 - 2009 SN - 1615-6854 SP - 474 EP - 481 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Grajewski, Matthias A1 - Köster, Michael A1 - Turek, Stefan T1 - Mathematical and Numerical Analysis of a Robust and Efficient Grid Deformation Method in the Finite Element Context JF - SIAM Journal on Scientific Computing Y1 - 2009 U6 - http://dx.doi.org/10.1137/050639387 VL - 31 IS - 2 SP - 1539 EP - 1557 PB - Society for Industrial and Applied Mathematics CY - Philadelphia, Pa. ER - TY - CHAP A1 - Staat, Manfred A1 - Tran, Thanh Ngoc A1 - Pham, Phu Tinh T1 - Limit and shakedown reliability analysis by nonlinear programming N2 - 7th International Conference on Reliability of Materials and Structures (RELMAS 2008). June 17 - 20, 2008 ; Saint Petersburg, Russia. pp 354-358. Reprint with corrections in red Introduction Analysis of advanced structures working under extreme heavy loading such as nuclear power plants and piping system should take into account the randomness of loading, geometrical and material parameters. The existing reliability are restricted mostly to the elastic working regime, e.g. allowable local stresses. Development of the limit and shakedown reliability-based analysis and design methods, exploiting potential of the shakedown working regime, is highly needed. In this paper the application of a new algorithm of probabilistic limit and shakedown analysis for shell structures is presented, in which the loading and strength of the material as well as the thickness of the shell are considered as random variables. The reliability analysis problems may be efficiently solved by using a system combining the available FE codes, a deterministic limit and shakedown analysis, and the First and Second Order Reliability Methods (FORM/SORM). Non-linear sensitivity analyses are obtained directly from the solution of the deterministic problem without extra computational costs. KW - Finite-Elemente-Methode KW - Limit analysis KW - Shakedown analysis Y1 - 2008 ER - TY - CHAP A1 - Tran, Thanh Ngoc A1 - Pham, Phu Tinh A1 - Staat, Manfred T1 - Reliability analysis of shells based on direct plasticity methods N2 - Abstracts der CD-Rom Proceedings of the 8th World Congress on Computational Mechanics (WCCM8) and 5th Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS 2008) 30.06. - 04.07.2008 Venedig, Italien. 2 Seiten Zusammenfassung der Autoren mit graph. Darst. und Literaturverzeichnis N2 - Abstracts of the Proceedings of the 8th World Congress on Computational Mechanics (WCCM8) and 5th Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS 2008) June 30th - July, 4th 2008, Venice, Italy. 2 pages with abstracts of the authors, Ill. and references. KW - Finite-Elemente-Methode KW - Limit analysis KW - Shakedown analysis KW - First-order reliability method KW - second-order reliability method KW - Sensitivity Y1 - 2008 ER -