@phdthesis{AlSaedy2015,
  author    = {Al-Saedy, Ammar Jaffar Muhesin},
  title     = {Normally solvable lagrangian boundary value problems},
  school      = {Universit{\"a}t Potsdam},
  pages     = {110},
  year      = {2015},
  language  = {en}
}
@unpublished{AizenbergTarkhanov1999,
  author    = {Aizenberg, Lev A. and Tarkhanov, Nikolai Nikolaevich},
  title     = {A Bohr phenomenon for elliptic equations},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-25547},
  year      = {1999},
  abstract  = {In 1914 Bohr proved that there is an r ∈ (0, 1) such that if a power series converges in the unit disk and its sum has modulus less than 1 then, for |z| < r, the sum of absolute values of its terms is again less than 1. Recently analogous results were obtained for functions of several variables. The aim of this paper is to comprehend the theorem of Bohr in the context of solutions to second order elliptic equations meeting the maximum principle.},
  language  = {en}
}
@unpublished{AizenbergTarkhanov2005,
  author    = {Aizenberg, Lev A. and Tarkhanov, Nikolai Nikolaevich},
  title     = {Stable expansions in homogeneous polynomials},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-29925},
  year      = {2005},
  abstract  = {An expansion for a class of functions is called stable if the partial sums are bounded uniformly in the class. Stable expansions are of key importance in numerical analysis where functions are given up to certain error. We show that expansions in homogeneous functions are always stable on a small ball around the origin, and evaluate the radius of the largest ball with this property.},
  language  = {en}
}
@unpublished{AizenbergTarkhanov2014,
  author    = {Aizenberg, Lev A. and Tarkhanov, Nikolai Nikolaevich},
  title     = {An integral formula for the number of lattice points in a domain},
  volume    = {3},
  number    = {3},
  publisher = {Universit{\"a}tsverlag Potsdam},
  address   = {Potsdam},
  issn      = {2193-6943},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-70453},
  pages     = {7},
  year      = {2014},
  abstract  = {Using the multidimensional logarithmic residue we show a simple formula for the difference between the number of integer points in a bounded domain of R^n and the volume of this domain. The difference proves to be the integral of an explicit differential form over the boundary of the domain.},
  language  = {en}
}
@unpublished{AirapetyanWitt1997,
  author    = {Airapetyan, Ruben and Witt, Ingo},
  title     = {Isometric properties of the Hankel Transformation in weighted sobolev spaces},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-25001},
  year      = {1997},
  abstract  = {It is shown that the Hankel transformation Hsub(v) acts in a class of weighted Sobolev spaces. Especially, the isometric mapping property of Hsub(v) which holds on L²(IRsub(+),rdr) is extended to spaces of arbitrary Sobolev order. The novelty in the approach consists in using techniques developed by B.-W. Schulze and others to treat the half-line Rsub(+) as a manifold with a conical singularity at r = 0. This is achieved by pointing out a connection between the Hankel transformation and the Mellin transformation.The procedure proposed leads at the same time to a short proof of the Hankel inversion formula. An application to the existence and higher regularity of solutions, including their asymptotics, to the 1-1-dimensional edge-degenerated wave equation is given.},
  language  = {en}
}
@article{AcevedoDeWiljesReich2017,
  author    = {Acevedo, Walter and De Wiljes, Jana and Reich, Sebastian},
  title     = {Second-order accurate ensemble transform particle filters},
  series = {SIAM journal on scientific computing},
  volume    = {39},
  journal   = {SIAM journal on scientific computing},
  number    = {5},
  publisher = {Society for Industrial and Applied Mathematics},
  address   = {Philadelphia},
  issn      = {1064-8275},
  doi       = {10.1137/16M1095184},
  pages     = {A1834 -- A1850},
  year      = {2017},
  abstract  = {Particle filters (also called sequential Monte Carlo methods) are widely used for state and parameter estimation problems in the context of nonlinear evolution equations. The recently proposed ensemble transform particle filter (ETPF) [S. Reich, SIAM T. Sci. Comput., 35, (2013), pp. A2013-A2014[ replaces the resampling step of a standard particle filter by a linear transformation which allows for a hybridization of particle filters with ensemble Kalman filters and renders the resulting hybrid filters applicable to spatially extended systems. However, the linear transformation step is computationally expensive and leads to an underestimation of the ensemble spread for small and moderate ensemble sizes. Here we address both of these shortcomings by developing second order accurate extensions of the ETPF. These extensions allow one in particular to replace the exact solution of a linear transport problem by its Sinkhorn approximation. It is also demonstrated that the nonlinear ensemble transform filter arises as a special case of our general framework. We illustrate the performance of the second-order accurate filters for the chaotic Lorenz-63 and Lorenz-96 models and a dynamic scene-viewing model. The numerical results for the Lorenz-63 and Lorenz-96 models demonstrate that significant accuracy improvements can be achieved in comparison to a standard ensemble Kalman filter and the ETPF for small to moderate ensemble sizes. The numerical results for the scene-viewing model reveal, on the other hand, that second-order corrections can lead to statistically inconsistent samples from the posterior parameter distribution.},
  language  = {en}
}
@unpublished{AbedSchulze2009,
  author    = {Abed, Jamil and Schulze, Bert-Wolfgang},
  title     = {Edge-degenerate families of ΨDO's on an infinite cylinder},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-30365},
  year      = {2009},
  abstract  = {We establish a parameter-dependent pseudo-differential calculus on an infinite cylinder, regarded as a manifold with conical exits to infinity. The parameters are involved in edge-degenerate form, and we formulate the operators in terms of operator-valued amplitude functions.},
  language  = {en}
}
@unpublished{AbedSchulze2008,
  author    = {Abed, Jamil and Schulze, Bert-Wolfgang},
  title     = {Operators with corner-degenerate symbols},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-30299},
  year      = {2008},
  abstract  = {We establish elements of a new approch to ellipticity and parametrices within operator algebras on a manifold with higher singularities, only based on some general axiomatic requirements on parameter-dependent operators in suitable scales of spaces. The idea is to model an iterative process with new generations of parameter-dependent operator theories, together with new scales of spaces that satisfy analogous requirements as the original ones, now on a corresponding higher level. The "full" calculus is voluminous; so we content ourselves here with some typical aspects such as symbols in terms of order reducing families, classes of relevant examples, and operators near the conical exit to infinity.},
  language  = {en}
}
@phdthesis{Abed2010,
  author    = {Abed, Jamil},
  title     = {An iterative approach to operators on manifolds with singularities},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-44757},
  school      = {Universit{\"a}t Potsdam},
  year      = {2010},
  abstract  = {We establish elements of a new approach to ellipticity and parametrices within operator algebras on manifolds with higher singularities, only based on some general axiomatic requirements on parameter-dependent operators in suitable scales of spaes. The idea is to model an iterative process with new generations of parameter-dependent operator theories, together with new scales of spaces that satisfy analogous requirements as the original ones, now on a corresponding higher level. The "full" calculus involves two separate theories, one near the tip of the corner and another one at the conical exit to infinity. However, concerning the conical exit to infinity, we establish here a new concrete calculus of edge-degenerate operators which can be iterated to higher singularities.},
  language  = {en}
}
@book{OPUS4-41720,
  title     = {Mathematik mit digitalen Medien - konkret},
  series = {Lernen, Lehren und Forschen mit digitalen Medien in der Primarstufe ; 4},
  journal   = {Lernen, Lehren und Forschen mit digitalen Medien in der Primarstufe ; 4},
  editor    = {Ladel, Silke and Kortenkamp, Ulrich and Etzold, Heiko},
  publisher = {WTM-Verlag},
  address   = {M{\"u}nster},
  isbn      = {978-3-95987-078-8},
  publisher      = {Universit{\"a}t Potsdam},
  year      = {2018},
  abstract  = {Neue Medien" war {\"u}ber viele Jahre hinweg das Codewort f{\"u}r Computer, die den Einzug in den Schulunterricht schaffen sollten - wenn es nach den Bef{\"u}rwortern ging. Die Widerst{\"a}nde, gerade in der Grundschule, waren groß und vielf{\"a}ltig. Es ist verst{\"a}ndlich, dass kurz nach der spielerischen Heranf{\"u}hrung an Bildung im Kindergarten, in einer Zeit, in der die Sch{\"u}lerinnen und Sch{\"u}ler auch das soziale Miteinander ein{\"u}ben m{\"u}ssen und auch fein- und grobmotorische F{\"a}higkeiten erwerben sollen, das vereinzelnde Sitzen vor einem Bildschirm nicht zu den obersten Priorit{\"a}ten geh{\"o}rt - und auch unserer Meinung nach nicht geh{\"o}ren sollte. In den letzten Jahren hat sich der Begriff der neuen Medien aber ver{\"a}ndert, und das, was bisher damit verbunden wurde, ist mit der „Digitalisierung" nicht nur des Schulunterrichts, sondern des ganzen Lebens, zu einem Dreh- und Angelpunkt der Bildung geworden. Statt klobigen Computern mit Bildschirmen, die das Miteinander schon {\"u}ber die Ausstattung der Computerr{\"a}ume in die falsche Bahn lenken, haben mobile Ger{\"a}te in der Hand der Sch{\"u}lerinnen und Sch{\"u}ler {\"u}bernommen. Diese k{\"o}nnen nun gemeinsam an einem Ger{\"a}t arbeiten, sie k{\"o}nnen direkt mit den Bildschirminhalten interagieren, sie k{\"o}nnen die Kameras, Mikrophone und Sensoren nutzen, um authentische Daten zu erfassen und zu verarbeiten, sie k{\"o}nnen auch außerhalb des Klassenraums oder der Schule damit arbeiten und haben inzwischen fast jederzeit das ganze Wissen des Internets mit dabei. Schwerpunkt dieses Bandes ist daher der Umgang mit Tablets und den darauf laufenden „Apps" im Mathematikunterricht. In f{\"u}nf Beitr{\"a}gen werden konkrete Unterrichtsvorschl{\"a}ge gemacht, die als Blaupausen f{\"u}r App-gest{\"u}tzten Unterricht dienen k{\"o}nnen. Erg{\"a}nzt wird dieser Band durch einen allgemeinen Leitfaden zur Beurteilung von Apps f{\"u}r den Mathematikunterricht samt Beispielen.},
  language  = {de}
}
@inproceedings{OPUS4-41526,
  title     = {Beitr{\"a}ge zum Mathematikunterricht 2017},
  editor    = {Kortenkamp, Ulrich and Kuzle, Ana},
  publisher = {WTM-Verlag},
  address   = {M{\"u}nster},
  isbn      = {978-3-95987-072-6},
  year      = {2018},
  language  = {de}
}
@book{OPUS4-43561,
  title     = {Implementation research on problem solving in school settings},
  series = {Ars inveniendi et dejudicandi ; 13},
  journal   = {Ars inveniendi et dejudicandi ; 13},
  editor    = {Kuzle, Ana and Rott, Benjamin and Gebel, Inga},
  publisher = {WTM-Verlag},
  address   = {M{\"u}nster},
  isbn      = {978-3-95987-116-7},
  pages     = {IV, 220},
  year      = {2019},
  language  = {en}
}