TY - JOUR A1 - Taylor, J. G. A1 - Schmitz, N. A1 - Ziemons, Karl A1 - Grosse-Ruyken, M.-L. A1 - Gruber, O. A1 - Müller-Gärtner, H.-W. A1 - Shah, N. J. T1 - The network of brain areas involved in the motion aftereffect JF - Neuroimage N2 - A network of brain areas is expected to be involved in supporting the motion aftereffect. The most active components of this network were determined by means of an fMRI study of nine subjects exposed to a visual stimulus of moving bars producing the effect. Across the subjects, common areas were identified during various stages of the effect, as well as networks of areas specific to a single stage. In addition to the well-known motion-sensitive area MT the prefrontal brain areas BA44 and 47 and the cingulate gyrus, as well as posterior sites such as BA37 and BA40, were important components during the period of the motion aftereffect experience. They appear to be involved in control circuitry for selecting which of a number of processing styles is appropriate. The experimental fMRI results of the activation levels and their time courses for the various areas are explored. Correlation analysis shows that there are effectively two separate and weakly coupled networks involved in the total process. Implications of the results for awareness of the effect itself are briefly considered in the final discussion. Y1 - 2000 SN - 1053-8119 VL - 11 IS - 4 SP - 257 EP - 270 ER - TY - JOUR A1 - Fink, G. R. A1 - Marshall, J. C. A1 - Shah, N. J. A1 - Weiss, P.H. A1 - Halligan, P. W. A1 - Grosse-Ruyken, M. A1 - Ziemons, Karl A1 - Zilles, K. A1 - Freund, H. J. T1 - Line bisection judgments implicate right parietal cortex and cerebellum as assessed by fMRI JF - Neurology Y1 - 2000 SN - 1526-632X VL - 54 IS - 6 SP - 1324 EP - 1331 ER - TY - JOUR A1 - Streun, M. A1 - Brandenburg, G. A1 - Larue, H. A1 - Zimmermann, E. A1 - Ziemons, Karl A1 - Halling, H. T1 - Pulse recording by free-running sampling JF - 2000 IEEE Nuclear Science Symposium Conference Record, Vol. 2 N2 - Pulses from a position-sensitive photomultiplier (PS-PMT) are recorded by free running ADCs at a sampling rate of 40 MHz. A four-channel acquisition-board has been developed which is equipped with four 12 bit-ADCs connected to one FPGA (field programmable gate array). The FPGA manages data acquisition and the transfer to the host computer. It can also work as a digital trigger, so a separate hardware-trigger can be omitted. The method of free running sampling provides a maximum of information, besides the pulse charge and amplitude also pulse shape and starting time are contained in the sampled data. These informations are crucial for many tasks such as distinguishing between different scintillator materials, determination of radiation type, pile-up recovery, coincidence detection or time-of-flight applications. The absence of an analog integrator allows coping with very high count rates. Since this method is going to be employed in positron emission tomography (PET), the position of an event is another important information. The simultaneous readout of four channels allows localization by means of center-of-gravity weighting. First results from a test setup with LSO-scintillators coupled to the PS-PMT are presented Y1 - 2000 SN - 1082-3654 SP - 9/179 EP - 9/181 ER - TY - JOUR A1 - Pieper, Martin A1 - Klein, Peter T1 - A simple and accurate numerical network flow model for bionic micro heat exchangers JF - Heat mass transfer Y1 - 2011 SN - 0947-7411 VL - 47 IS - 5 SP - 491 EP - 503 PB - Springer CY - Berlin ER - TY - JOUR A1 - Pieper, Martin A1 - Klein, Peter T1 - Application of simple, periodic homogenization techniques to non-linear heat conduction problems in non-periodic, porous media JF - Heat mass transfer N2 - Often, detailed simulations of heat conduction in complicated, porous media have large runtimes. Then homogenization is a powerful tool to speed up the calculations by preserving accurate solutions at the same time. Unfortunately real structures are generally non-periodic, which requires unpractical, complicated homogenization techniques. We demonstrate in this paper, that the application of simple, periodic techniques to realistic media, that are just close to periodic, gives accurate, approximative solutions. In order to obtain effective parameters for the homogenized heat equation, we have to solve a so called “cell problem”. In contrast to periodic structures it is not trivial to determine a suitable unit cell, which represents a non-periodic media. To overcome this problem, we give a rule of thumb on how to choose a good cell. Finally we demonstrate the efficiency of our method for virtually generated foams as well as real foams and compare these results to periodic structures. Y1 - 2012 U6 - https://doi.org/10.1007/s00231-011-0879-4 SN - 0947-7411 VL - 48 IS - 2 SP - 291 EP - 300 PB - Springer CY - Berlin ER - TY - JOUR A1 - Pieper, Martin A1 - Klein, Peter T1 - Numerical solution of the heat equation with non-linear, time derivative-dependent source term JF - International Journal for Numerical Methods in Engineering N2 - The mathematical modeling of heat conduction with adsorption effects in coated metal structures yields the heat equation with piecewise smooth coefficients and a new kind of source term. This term is special, because it is non-linear and furthermore depends on a time derivative. In our approach we reformulated this as a new problem for the usual heat equation, without source term but with a new non-linear coefficient. We gave an existence and uniqueness proof for the weak solution of the reformulated problem. To obtain a numerical solution, we developed a semi-implicit and a fully implicit finite volume method. We compared these two methods theoretically as well as numerically. Finally, as practical application, we simulated the heat conduction in coated aluminum fibers with adsorption in the zeolite coating. Copyright © 2010 John Wiley & Sons, Ltd. Y1 - 2010 U6 - https://doi.org/10.1002/nme.2937 SN - 0029-5981 VL - 84 IS - 10 SP - 1205 EP - 1221 PB - Wiley CY - Chichester ER - TY - JOUR A1 - Pieper, Martin T1 - Nonlinear integral equations for an inverse electromagnetic scattering problem JF - Journal of Physics Conference Series. 124 (2008) Y1 - 2008 SN - 1742-6596 ER - TY - JOUR A1 - Pieper, Martin A1 - Ivanyshyn, Olha T1 - Nonlinear integral equations for a 3D inverse acoustic scattering problem : abstract / O. Ivanyshyn and M. Pieper Y1 - 2008 N1 - World Congress on Computational Mechanics <8, 2008, Venedig> ; European Congress on Computational Methods in Applied Sciences and Engineering <5, 2008, Venedig> ER - TY - JOUR A1 - Ewe, Hendrik A1 - Klein, Peter A1 - Pieper, Martin A1 - Füldner, G. T1 - Heat conductivity in sintered aluminium fibers JF - Cellular metals for structural and functional applications : CELLMET 2008 ; proceedings of the International Symposium on Cellular Metals for Structural and Functional Applications held October 8 - 10, 2008 in Dresden, Germany / ed. by Günter Stephani Y1 - 2009 SP - 187 EP - 193 PB - Fraunhofer IFAM CY - Dresden ER - TY - JOUR A1 - Pieper, Martin T1 - Multiobjective optimization with expensive objectives applied to a thermodynamic material design problem JF - Proceedings in applied mathematics and mechanics : PAMM. 11 (2011), H. 1 Y1 - 2011 SN - 1617-7061 SP - 733 EP - 734 PB - Wiley CY - Weinheim ER -