University of Paderborn

About: University of Paderborn is a education organization based out in Paderborn, Nordrhein-Westfalen, Germany. It is known for research contribution in the topics: Control reconfiguration & Software. The organization has 6684 authors who have published 16929 publications receiving 323154 citations.

The SCC-DFTB method and its application to biological systems

Abstract: The Self-consistent charge density functional tight-binding (SCC-DFTB) is an approximate quantum chemical method derived from density functional theory (DFT) based on a second-order expansion of the DFT total energy expression. Here, we review in detail the application of SCC-DFTB to biological systems and several extensions of the original formalism. The biological systems discussed turn out to be a challenge for DFT due to the occurrence of weak binding forces and charge transfer problems, both of which are not properly described by recent DFT-GGA functionals. Possible solutions and alternative strategies are presented and the role of SCC-DFTB in a general quantum chemical approach to biological systems is discussed

An Approach to Modelling and Simulation of Uncertain Dynamical Systems

Abstract: Coping with uncertainty in dynamical systems has recently received some attention in artificial intelligence (AI), particularly in the fields of qualitative and model-based reasoning. In this paper, we propose an approach to modelling and simulation of uncertain dynamics which is based on the following ideas: We consider (linguistic) descriptions of uncertain functional relationships characterizing the behavior of some dynamical system. Based on a certain interpretation of such rule-based models, we derive a fuzzy function $\tilde{F}$. It will be shown that all (reasonable) fuzzy functions can be approximated to any degree of accuracy in this way. The function $\tilde{F}$ is then used as the "fuzzy" right hand side of a set of differential equations, which leads us to consider fuzzy initial value problems. We are going to propose an interpretation of such problems. Moreover, several aspects of simulation methods for characterizing the set of all system behaviors compatible with this interpretation will be...

Integrable theory of the perturbation equations

Abstract: An integrable theory is developed for the perturbation equations engendered from small disturbances of solutions. It includes various integrable properties of the perturbation equations, such as hereditary recursion operators, master symmetries, linear representations (Lax and zero curvature representations) and Hamiltonian structures, and provides us with a method of generating hereditary operators, Hamiltonian operators and symplectic operators starting from the known ones. The resulting perturbation equations give rise to a sort of integrable coupling of soliton equations. Two examples (MKdV hierarchy and KP equation) are carefully carried out.

Porous Graphene as an Atmospheric Nanofilter

Abstract: The fabrication of nanoscale membranes exhibiting high selectivity is an emerging field of research. The possibility to use bottom-up approaches to fabricate a filter with porous graphene and analyze its functionality with first principle calculations is investigated. Here, the porous network is produced by self-assembly of the hexaiodo-substituted macrocycle cyclohexa-m-phenylene (CHP). The resulting porous network exhibits an extremely high selectivity in favor of H(2) and He among other atmospheric gases, such as Ne, O(2), N(2), CO, CO(2), NH(3), and Ar. The presented membrane is superior to traditional filters using polymers or silica and could have great potential for further technological applications such as gas sensors or fuel cells.

Tight-binding approach to time-dependent density-functional response theory

Abstract: In this paper we propose an extension of the self-consistent charge-density-functional tight-binding (SCC-DFTB) method [M. Elstner et al., Phys. Rev. B 58, 7260 (1998)], which allows the calculation of the optical properties of finite systems within time-dependent density-functional response theory (TD-DFRT). For a test set of small organic molecules low-lying singlet excitation energies are computed in good agreement with first-principles and experimental results. The overall computational cost of this parameter-free method is very low and thus it allows us to examine large systems: we report successful applications to ${\mathrm{C}}_{60}$ and the polyacene series.