@unpublished{BraunFeudelGuzdar1998, author = {Braun, Robert and Feudel, Fred and Guzdar, Parvez}, title = {The route to chaos for a two-dimensional externally driven flow}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-14717}, year = {1998}, abstract = {We have numerically studied the bifurcations and transition to chaos in a two-dimensional fluid for varying values of the Reynolds number. These investigations have been motivated by experiments in fluids, where an array of vortices was driven by an electromotive force. In these experiments, successive changes leading to a complex motion of the vortices, due to increased forcing, have been explored [Tabeling, Perrin, and Fauve, J. Fluid Mech. 213, 511 (1990)]. We model this experiment by means of two-dimensional Navier-Stokes equations with a special external forcing, driving a linear chain of eight counter-rotating vortices, imposing stress-free boundary conditions in the vertical direction and periodic boundary conditions in the horizontal direction. As the strength of the forcing or the Reynolds number is raised, the original stationary vortex array becomes unstable and a complex sequence of bifurcations is observed. Several steady states and periodic branches and a period doubling cascade appear on the route to chaos. For increasing values of the Reynolds number, shear flow develops, for which the spatial scale is large compared to the scale of the forcing. Furthermore, we have investigated the influence of the aspect ratio of the container as well as the effect of no-slip boundary conditions at the top and bottom, on the bifurcation scenario.}, language = {en} } @unpublished{BraunFeudel1996, author = {Braun, Robert and Feudel, Fred}, title = {Supertransient chaos in the two-dimensional complex Ginzburg-Landau equation}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-14099}, year = {1996}, abstract = {We have shown that the two-dimensional complex Ginzburg-Landau equation exhibits supertransient chaos in a certain parameter range. Using numerical methods this behavior is found near the transition line separating frozen spiral solutions from turbulence. Supertransient chaos seems to be a common phenomenon in extended spatiotemporal systems. These supertransients are characterized by an average transient lifetime which depends exponentially on the size of the system and are due to an underlying nonattracting chaotic set.}, language = {en} } @unpublished{BraunFeudelSeehafer1997, author = {Braun, Robert and Feudel, Fred and Seehafer, Norbert}, title = {Bifurcations and chaos in an array of forced vortices}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-14564}, year = {1997}, abstract = {We have studied the bifurcation structure of the incompressible two-dimensional Navier-Stokes equations with a special external forcing driving an array of 8×8 counterrotating vortices. The study has been motivated by recent experiments with thin layers of electrolytes showing, among other things, the formation of large-scale spatial patterns. As the strength of the forcing or the Reynolds number is raised the original stationary vortex array becomes unstable and a complex sequence of bifurcations is observed. The bifurcations lead to several periodic branches, torus and chaotic solutions, and other stationary solutions. Most remarkable is the appearance of solutions characterized by structures on spatial scales large compared to the scale of the forcing. We also characterize the different dynamic regimes by means of tracers injected into the fluid. Stretching rates and Hausdorff dimensions of convected line elements are calculated to quantify the mixing process. It turns out that for time-periodic velocity fields the mixing can be very effective.}, language = {en} } @article{BraunFeudelSeehafer1997, author = {Braun, Robert and Feudel, Fred and Seehafer, Norbert}, title = {Bifurcations and chaos in an array of forced vortices}, year = {1997}, language = {en} } @book{BraunFeudelSeehafer1997, author = {Braun, Robert and Feudel, Fred and Seehafer, Norbert}, title = {Bifurcations and chaos in an array of forced vortices}, series = {Preprint NLD}, volume = {37}, journal = {Preprint NLD}, publisher = {Univ. Potsdam}, address = {Potsdam}, issn = {1432-2935}, pages = {7 S. : graph. Darst.}, year = {1997}, language = {en} } @phdthesis{Braun1997, author = {Braun, Robert}, title = {Bifurkationen und Strukturbildung in hydrodynamischen Systemen}, pages = {VII, 103 S. : graph. Darst.}, year = {1997}, language = {de} } @article{MontavonBraunKruegeretal.2013, author = {Montavon, Gregoire and Braun, Mikio L. and Kr{\"u}ger, Tammo and M{\"u}ller, Klaus-Robert}, title = {Analyzing local structure in Kernel-Based learning}, series = {IEEE signal processing magazine}, volume = {30}, journal = {IEEE signal processing magazine}, number = {4}, publisher = {Inst. of Electr. and Electronics Engineers}, address = {Piscataway}, issn = {1053-5888}, doi = {10.1109/MSP.2013.2249294}, pages = {62 -- 74}, year = {2013}, language = {en} } @article{WittFeudelGebogietal.1998, author = {Witt, Annette and Feudel, Fred and Gebogi, C. and Kurths, J{\"u}rgen and Braun, Robert}, title = {Tracer dynamics in a flow of driven vortices}, series = {Preprint NLD}, volume = {51}, journal = {Preprint NLD}, publisher = {Univ.}, address = {Potsdam}, issn = {1432-2935}, pages = {8 S. : graph. Darst.}, year = {1998}, language = {en} } @book{BraunFeudelGuzdar1998, author = {Braun, Robert and Feudel, Fred and Guzdar, P.}, title = {The route to chaos for a two-dimensional externally driven flow : [to appear in Physical Review E]}, series = {Preprint NLD}, volume = {46}, journal = {Preprint NLD}, publisher = {Univ. Potsdam}, address = {Potsdam}, issn = {1432-2935}, pages = {7 S. : graph. Darst.}, year = {1998}, language = {en} } @article{BraunFeudelGuzdar1998, author = {Braun, Robert and Feudel, Fred and Guzdar, P.}, title = {The route to chaos for a two-dimensional externally driven flow}, year = {1998}, language = {en} } @book{BraunFeudel1996, author = {Braun, Robert and Feudel, Fred}, title = {Supertransient chaos in the two-dimensional complex Ginzburg-Landau equation}, series = {Preprint NLD}, volume = {29}, journal = {Preprint NLD}, publisher = {Univ.}, address = {Potsdam}, pages = {8 S.}, year = {1996}, language = {en} } @article{BraunFeudelGebogietal.1999, author = {Braun, Robert and Feudel, Fred and Gebogi, C. and Kurths, J{\"u}rgen and Witt, Annette}, title = {Tracer dynamics in a flow of driven vortices}, year = {1999}, language = {en} } @article{WirthHatterDrostetal.2015, author = {Wirth, Jonas and Hatter, Nino and Drost, Robert and Umbach, Tobias R. and Barja, Sara and Zastrow, Matthias and R{\"u}ck-Braun, Karola and Pascual, Jose Ignacio and Saalfrank, Peter and Franke, Katharina J.}, title = {Diarylethene Molecules on a Ag(111) Surface: Stability and Electron-Induced Switching}, series = {The journal of physical chemistry : C, Nanomaterials and interfaces}, volume = {119}, journal = {The journal of physical chemistry : C, Nanomaterials and interfaces}, number = {9}, publisher = {American Chemical Society}, address = {Washington}, issn = {1932-7447}, doi = {10.1021/jp5122036}, pages = {4874 -- 4883}, year = {2015}, abstract = {Diarylethene derivatives are photochromic molecular switches, undergoing a ring-opening/-closing reaction by illumination with light. The symmetry of the closed form is determined by the WoodWard Hoffinann rules according to which the reaction proceeds by corirotatory rotation -in that case. Here, we show by a cOrnbined approach of scanning tunneling microscopy (STM) and density functional theory (DFT) calculations that the Open isomer of 4,4'-(4,4'-(perfluorocydopent-1-ene-1,2-diyl)bis(5-methyl-thiophent-4,2,4-dipyridine) (PDTE) retains its open form upon adsorption on a Ag(111) surface. It caribe switched into a closed form, which we identify as the digrotatOly cydization product, by controlled manipulation 'With the STM tip, Evidence of an electric-field dependent switching-process 'is interpreted on the basis of a Simple electroStatic Model, which suggests that the reaction proceedS via an "upright" intermediate state. This pathway thus strongly differs from the switching reaction in solution.}, language = {en} } @book{BeinBraunDaaseetal.2020, author = {Bein, Leon and Braun, Tom and Daase, Bj{\"o}rn and Emsbach, Elina and Matthes, Leon and Stiede, Maximilian and Taeumel, Marcel and Mattis, Toni and Ramson, Stefan and Rein, Patrick and Hirschfeld, Robert and M{\"o}nig, Jens}, title = {SandBlocks}, number = {132}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, isbn = {978-3-86956-482-1}, issn = {1613-5652}, doi = {10.25932/publishup-43926}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-439263}, publisher = {Universit{\"a}t Potsdam}, pages = {viii, 212}, year = {2020}, abstract = {Visuelle Programmiersprachen werden heutzutage zugunsten textueller Programmiersprachen nahezu nicht verwendet, obwohl visuelle Programmiersprachen einige Vorteile bieten. Diese reichen von der Vermeidung von Syntaxfehlern, {\"u}ber die Nutzung konkreter dom{\"a}nenspezifischer Notation bis hin zu besserer Lesbarkeit und Wartbarkeit des Programms. Trotzdem greifen professionelle Softwareentwickler nahezu ausschließlich auf textuelle Programmiersprachen zur{\"u}ck. Damit Entwickler diese Vorteile visueller Programmiersprachen nutzen k{\"o}nnen, aber trotzdem nicht auf die ihnen bekannten textuellen Programmiersprachen verzichten m{\"u}ssen, gibt es die Idee, textuelle und visuelle Programmelemente gemeinsam in einer Programmiersprache nutzbar zu machen. Damit ist dem Entwickler {\"u}berlassen wann und wie er visuelle Elemente in seinem Programmcode verwendet. Diese Arbeit stellt das SandBlocks-Framework vor, das diese gemeinsame Nutzung visueller und textueller Programmelemente erm{\"o}glicht. Neben einer Auswertung visueller Programmiersprachen, zeigt es die technische Integration visueller Programmelemente in das Squeak/Smalltalk-System auf, gibt Einblicke in die Umsetzung und Verwendung in Live-Programmiersystemen und diskutiert ihre Verwendung in unterschiedlichen Dom{\"a}nen.}, language = {de} } @article{AbeysekaraArcherBenbowetal.2018, author = {Abeysekara, A. U. and Archer, A. and Benbow, Wystan and Bird, Ralph and Brose, Robert and Buchovecky, M. and Buckley, J. H. and Bugaev, V. and Chromey, A. J. and Connolly, M. P. and Cui, Wei and Daniel, M. K. and Falcone, A. and Feng, Qi and Finley, John P. and Fortson, L. and Furniss, Amy and Huetten, M. and Hanna, David and Hervet, O. and Holder, J. and Hughes, G. and Humensky, T. B. and Johnson, Caitlin A. and Kaaret, Philip and Kar, P. and Kertzman, M. and Kieda, David and Krause, M. and Krennrich, F. and Kumar, S. and Lang, M. J. and Lin, T. T. Y. and McArthur, S. and Moriarty, P. and Mukherjee, Reshmi and Ong, R. A. and Otte, Adam Nepomuk and Park, Nahee and Petrashyk, A. and Pohl, Martin and Pueschel, Elisa and Quinn, J. and Ragan, K. and Reynolds, P. T. and Richards, Gregory T. and Roache, E. and Rulten, C. and Sadeh, I. and Santander, Marcos and Sembroski, G. H. and Shahinyan, Karlen and Sushch, I. and Tyler, J. and Wakely, S. P. and Weinstein, A. and Wells, R. M. and Wilcox, P. and Wilhelm, Alina and Williams, D. A. and Williamson, T. J. and Zitzer, B. and Abdollahi, S. and Ajello, Marco and Baldini, Luca and Barbiellini, G. and Bastieri, Denis and Bellazzini, Ronaldo and Berenji, B. and Bissaldi, Elisabetta and Blandford, R. D. and Bonino, R. and Bottacini, E. and Brandt, Terri J. and Bruel, P. and Buehler, R. and Cameron, R. A. and Caputo, R. and Caraveo, P. A. and Castro, D. and Cavazzuti, E. and Charles, Eric and Chiaro, G. and Ciprini, S. and Cohen-Tanugi, Johann and Costantin, D. and Cutini, S. and de Palma, F. and Di Lalla, N. and Di Mauro, M. and Di Venere, L. and Dominguez, A. and Favuzzi, C. and Fegan, S. J. and Franckowiak, Anna and Fukazawa, Yasushi and Funk, Stefan and Fusco, Piergiorgio and Gargano, Fabio and Gasparrini, Dario and Giglietto, Nicola and Giordano, F. and Giroletti, Marcello and Green, D. and Grenier, I. A. and Guillemot, L. and Guiriec, Sylvain and Hays, Elizabeth and Hewitt, John W. and Horan, D. and Johannesson, G. and Kensei, S. and Kuss, M. and Larsson, Stefan and Latronico, L. and Lemoine-Goumard, Marianne and Li, J. and Longo, Francesco and Loparco, Francesco and Lovellette, M. N. and Lubrano, Pasquale and Magill, Jeffrey D. and Maldera, Simone and Mazziotta, Mario Nicola and McEnery, J. E. and Michelson, P. F. and Mitthumsiri, W. and Mizuno, Tsunefumi and Monzani, Maria Elena and Morselli, Aldo and Moskalenko, Igor V. and Negro, M. and Nuss, E. and Ojha, R. and Omodei, Nicola and Orienti, M. and Orlando, E. and Palatiello, M. and Paliya, Vaidehi S. and Paneque, D. and Perkins, Jeremy S. and Persic, M. and Pesce-Rollins, Melissa and Petrosian, Vahe' and Piron, F. and Porter, Troy A. and Principe, G. and Raino, S. and Rando, Riccardo and Rani, B. and Razzano, Massimilano and Razzaque, Soebur and Reimer, A. and Reimer, Olaf and Reposeur, T. and Sgro, C. and Siskind, E. J. and Spandre, Gloria and Spinelli, P. and Suson, D. J. and Tajima, Hiroyasu and Thayer, J. B. and Thompson, David J. and Torres, Diego F. and Tosti, Gino and Troja, Eleonora and Valverde, J. and Vianello, Giacomo and Vogel, M. and Wood, K. and Yassine, M. and Alfaro, R. and Alvarez, C. and Alvarez, J. D. and Arceo, R. and Arteaga-Velazquez, J. C. and Rojas, D. Avila and Ayala Solares, H. A. and Becerril, A. and Belmont-Moreno, E. and BenZvi, S. Y. and Bernal, A. and Braun, J. and Brisbois, C. and Caballero-Mora, K. S. and Capistran, T. and Carraminana, A. and Casanova, Sabrina and Castillo, M. and Cotti, U. and Cotzomi, J. and Coutino de Leon, S. and De Leon, C. and De la Fuente, E. and Dichiara, S. and Dingus, B. L. and DuVernois, M. A. and Diaz-Velez, J. C. and Engel, K. and Enriquez-Rivera, O. and Fiorino, D. W. and Fleischhack, H. and Fraija, N. and Garcia-Gonzalez, J. A. and Garfias, F. and Gonzalez Munoz, A. and Gonzalez, M. M. and Goodman, J. A. and Hampel-Arias, Z. and Harding, J. P. and Hernandez, S. and Hernandez-Almada, A. and Hona, B. and Hueyotl-Zahuantitla, F. and Hui, C. M. and Huntemeyer, P. and Iriarte, A. and Jardin-Blicq, A. and Joshi, V. and Kaufmann, S. and Lara, A. and Lauer, R. J. and Lee, W. H. and Lennarz, D. and Leon Vargas, H. and Linnemann, J. T. and Longinotti, A. L. and Luis-Raya, G. and Luna-Garcia, R. and Lopez-Coto, R. and Malone, K. and Marinelli, S. S. and Martinez, O. and Martinez-Castellanos, I. and Martinez-Castro, J. and Martinez-Huerta, H. and Matthews, J. A. and Miranda-Romagnoli, P. and Moreno, E. and Mostafa, M. and Nayerhoda, A. and Nellen, L. and Newbold, M. and Nisa, M. U. and Noriega-Papaqui, R. and Pelayo, R. and Pretz, J. and Perez-Perez, E. G. and Ren, Z. and Rho, C. D. and Riviere, C. and Rosa-Gonzalez, D. and Rosenberg, M. and Ruiz-Velasco, E. and Salazar, H. and Greus, F. Salesa and Sandoval, A. and Schneider, M. and Arroyo, M. Seglar and Sinnis, G. and Smith, A. J. and Springer, R. W. and Surajbali, P. and Taboada, Ignacio and Tibolla, O. and Tollefson, K. and Torres, I. and Ukwatta, Tilan N. and Villasenor, L. and Weisgarber, T. and Westerhoff, Stefan and Wisher, I. G. and Wood, J. and Yapici, Tolga and Yodh, G. and Zepeda, A. and Zhou, H.}, title = {VERITAS and Fermi-LAT Observations of TeV Gamma-Ray Sources Discovered by HAWC in the 2HWC Catalog}, series = {The astrophysical journal : an international review of spectroscopy and astronomical physics}, volume = {866}, journal = {The astrophysical journal : an international review of spectroscopy and astronomical physics}, number = {1}, publisher = {IOP Publ. Ltd.}, address = {Bristol}, organization = {VERITAS Collaboration Fermi-LAT Collaboration HAWC Collaboration}, issn = {0004-637X}, doi = {10.3847/1538-4357/aade4e}, pages = {18}, year = {2018}, abstract = {The High Altitude Water Cherenkov (HAWC) collaboration recently published their 2HWC catalog, listing 39 very high energy (VHE; >100 GeV) gamma-ray sources based on 507 days of observation. Among these, 19 sources are not associated with previously known teraelectronvolt (TeV) gamma-ray sources. We have studied 14 of these sources without known counterparts with VERITAS and Fermi-LAT. VERITAS detected weak gamma-ray emission in the 1 TeV-30 TeV band in the region of DA 495, a pulsar wind nebula coinciding with 2HWC J1953+294, confirming the discovery of the source by HAWC. We did not find any counterpart for the selected 14 new HAWC sources from our analysis of Fermi-LAT data for energies higher than 10 GeV. During the search, we detected gigaelectronvolt (GeV) gamma-ray emission coincident with a known TeV pulsar wind nebula, SNR G54.1+0.3 (VER J1930+188), and a 2HWC source, 2HWC J1930+188. The fluxes for isolated, steady sources in the 2HWC catalog are generally in good agreement with those measured by imaging atmospheric Cherenkov telescopes. However, the VERITAS fluxes for SNR G54.1+0.3, DA 495, and TeV J2032+4130 are lower than those measured by HAWC, and several new HAWC sources are not detected by VERITAS. This is likely due to a change in spectral shape, source extension, or the influence of diffuse emission in the source region.}, language = {en} }