@article{FischerWaldhausenHorenkoetal.2007, author = {Fischer, Alexander and Waldhausen, S. and Horenko, Illia and Meerbach, E. and Sch{\"u}tte, Christof}, title = {Identification of Biomolecular Conformations from Incomplete Torsion Angle Observations by Hidden Markov Models}, volume = {28}, journal = {J. Comp. Chem.}, number = {15}, doi = {10.1002/jcc.20692}, pages = {2453 -- 2464}, year = {2007}, language = {en} } @article{HorenkoDittmerFischeretal.2006, author = {Horenko, Illia and Dittmer, E. and Fischer, Alexander and Sch{\"u}tte, Christof}, title = {Automated Model Reduction for Complex Systems exhibiting Metastability}, volume = {5}, journal = {Mult. Mod. Sim.}, number = {3}, doi = {10.1137/050623310}, pages = {802 -- 827}, year = {2006}, language = {en} } @article{FischerCordesSchuette1998, author = {Fischer, Alexander and Cordes, Frank and Sch{\"u}tte, Christof}, title = {Hybrid Monte Carlo with adaptive temperature in mixed-canonical ensemble}, volume = {19}, journal = {J. Comp. Chem.}, number = {15}, doi = {10.1002/(SICI)1096-987X(19981130)19:15<1689::AID-JCC2>3.0.CO;2-J}, pages = {1689 -- 1697}, year = {1998}, language = {en} } @inproceedings{FischerSchuetteDeuflhardetal.2002, author = {Fischer, Alexander and Sch{\"u}tte, Christof and Deuflhard, Peter and Cordes, Frank}, title = {Hierarchical Uncoupling-Coupling of Metastable Conformations}, volume = {24}, booktitle = {Computational Methods for Macromolecules}, editor = {Schlick, T. and Gan, H.}, publisher = {Springer}, pages = {235 -- 259}, year = {2002}, language = {en} } @misc{SchuetteFischerHuisingaetal.1999, author = {Sch{\"u}tte, Christof and Fischer, Alexander and Huisinga, Wilhelm and Deuflhard, Peter}, title = {A Direct Approach to Conformational Dynamics based on Hybrid Monte Carlo}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-3889}, number = {SC-98-45}, year = {1999}, abstract = {Recently, a novel concept for the computation of essential features of the dynamics of Hamiltonian systems (such as molecular dynamics) has been proposed. The realization of this concept had been based on subdivision techniques applied to the Frobenius--Perron operator for the dynamical system. The present paper suggests an alternative but related concept that merges the conceptual advantages of the dynamical systems approach with the appropriate statistical physics framework. This approach allows to define the phrase ``conformation'' in terms of the dynamical behavior of the molecular system and to characterize the dynamical stability of conformations. In a first step, the frequency of conformational changes is characterized in statistical terms leading to the definition of some Markov operator \$T\$ that describes the corresponding transition probabilities within the canonical ensemble. In a second step, a discretization of \$T\$ via specific hybrid Monte Carlo techniques is shown to lead to a stochastic matrix \$P\$. With these theoretical preparations, an identification algorithm for conformations is applicable. It is demonstrated that the discretization of \$T\$ can be restricted to few essential degrees of freedom so that the combinatorial explosion of discretization boxes is prevented and biomolecular systems can be attacked. Numerical results for the n-pentane molecule and the triribonucleotide adenylyl\emph{(3'-5')}cytidylyl\emph{(3'-5')}cytidin are given and interpreted.}, language = {en} } @misc{FischerCordesSchuette1997, author = {Fischer, Alexander and Cordes, Frank and Sch{\"u}tte, Christof}, title = {Hybrid Monte Carlo with Adaptive Temperature in a Mixed-Canonical Ensemble: Efficient Conformational Analysis of RNA}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-3364}, number = {SC-97-67}, year = {1997}, abstract = {A hybrid Monte Carlo method with adaptive temperature choice is presented, which exactly generates the distribution of a mixed-canonical ensemble composed of two canonical ensembles at low and high temperature. The analysis of resulting Markov chains with the reweighting technique shows an efficient sampling of the canonical distribution at low temperature, whereas the high temperature component facilitates conformational transitions, which allows shorter simulation times. \\The algorithm was tested by comparing analytical and numerical results for the small n-butane molecule before simulations were performed for a triribonucleotide. Sampling the complex multi-minima energy landscape of these small RNA segments, we observed enforced crossing of energy barriers.}, language = {en} } @misc{Fischer2000, author = {Fischer, Alexander}, title = {An Uncoupling-Coupling Technique for Markov Chain Monte Carlo Methods}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-5720}, number = {00-04}, year = {2000}, abstract = {Uncoupling-coupling Monte Carlo (UCMC) combines uncoupling techniques for finite Markov chains with Markov chain Monte Carlo methodology. By determining almost invariant sets of the associated Markov operator, the Monte Carlo sampling splits by a hierarchical annealing process into the essential regions of the state space; therefore UCMC aims at avoiding the typical metastable behavior of Monte Carlo techniques. From the viewpoint of Monte Carlo, a slowly converging long-time Markov chain is replaced by a limited number of rapidly mixing short-time ones. The correct weighting factors for the various Markov chains are obtained via a coupling matrix, that connects the samplings from the different almost invariant sets. The underlying mathematical structure of this approach is given by a general examination of the uncoupling-coupling procedure. Furthermore, the overall algorithmic scheme of UCMC is applied to the \$n\$-pentane molecule, a well-known example from molecular dynamics.}, language = {en} } @misc{DeuflhardHuisingaFischeretal.1998, author = {Deuflhard, Peter and Huisinga, Wilhelm and Fischer, Alexander and Sch{\"u}tte, Christof}, title = {Identification of Almost Invariant Aggregates in Reversible Nearly Uncoupled Markov Chains}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-3469}, number = {SC-98-03}, year = {1998}, abstract = {The topic of the present paper bas been motivated by a recent computational approach to identify chemical conformations and conformational changes within molecular systems. After proper discretization, the conformations show up as almost invariant aggregates in reversible nearly uncoupled Markov chains. Most of the former work on this subject treated the direct problem: given the aggregates, analyze the loose coupling in connection with the computation of the stationary distribution (aggregation/disaggregation techniques). In contrast to that the present paper focuses on the inverse problem: given the system as a whole, identify the almost invariant aggregates together with the associated transition probabilites. A rather simple and robust algorithm is suggested and illustrated by its application to the n-pentane molecule.}, language = {en} } @misc{SchuetteFischerHuisingaetal.1998, author = {Sch{\"u}tte, Christof and Fischer, Alexander and Huisinga, Wilhelm and Deuflhard, Peter}, title = {A Hybrid Monte Carlo Method for Essential Molecular Dynamics}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-3474}, number = {SC-98-04}, year = {1998}, abstract = {Recently, a novel concept for the computation of essential features of Hamiltonian systems (such as those arising in molecular dynamics) has been proposed. The realization of that concept was based on subdivision techniques applied to the Frobenius--Perron operator for the dynamical system. The present paper suggests an alternative but related concept based on statistical mechanics, which allows to attack realistic molecular systems. In a first step, the frequency of conformational changes is characterized in statistical terms leading to the definition of some Markov operator \$T\$ that describes the corresponding transition probabilities within the canonical ensemble. In a second step, a discretization of \$T\$ via hybrid Monte Carlo techniques (based on short term subtrajectories only) is shown to lead to a stochastic matrix \$P\$. With these theoretical preparations, an identification algorithm for conformations is applicable (to be presented elsewhere). Numerical results for the n-pentane molecule are given and interpreted.}, language = {en} } @article{DeuflhardHuisingaFischeretal.2000, author = {Deuflhard, Peter and Huisinga, Wilhelm and Fischer, Alexander and Sch{\"u}tte, Christof}, title = {Identification of Almost Invariant Aggregates in Reversible Nearly Uncoupled Markov Chains}, volume = {315}, journal = {Lin. Alg. Appl.}, pages = {39 -- 59}, year = {2000}, language = {en} } @article{KoschekDurmazKrylovaetal.2015, author = {Koschek, and Durmaz, Vedat and Krylova, and Wieczorek, and Gupta, Pooja and Richter, and Bujotzek, Alexander and Fischer, and Haag, Rainer and Freund, and Weber, Marcus and Rademann,}, title = {Peptide polymer ligands for a tandem WW-domain, a soft multivalent protein-protein interaction: lessons on the thermodynamic fitness of flexible ligands}, volume = {11}, journal = {Beilstein J. Org. Chem.}, pages = {837 -- 847}, year = {2015}, language = {en} } @article{HeinzeDipankarHenkenetal.2017, author = {Heinze, Rieke and Dipankar, Anurag and Henken, Cintia Carbajal and Moseley, Christopher and Sourdeval, Odran and Tr{\"o}mel, Silke and Xie, Xinxin and Adamidis, Panos and Ament, Felix and Baars, Holger and Barthlott, Christian and Behrendt, Andreas and Blahak, Ulrich and Bley, Sebastian and Brdar, Slavko and Brueck, Matthias and Crewell, Susanne and Deneke, Hartwig and Di Girolamo, Paolo and Evaristo, Raquel and Fischer, J{\"u}rgen and Frank, Christopher and Friederichs, Petra and G{\"o}cke, Tobias and Gorges, Ksenia and Hande, Luke and Hanke, Moritz and Hansen, Akio and Hege, Hans-Christian and Hose, Corinna and Jahns, Thomas and Kalthoff, Norbert and Klocke, Daniel and Kneifel, Stefan and Knippertz, Peter and Kuhn, Alexander and van Laar, Thriza and Macke, Andreas and Maurer, Vera and Mayer, Bernhard and Meyer, Catrin I. and Muppa, Shravan K. and Neggers, Roeland A. J. and Orlandi, Emiliano and Pantillon, Florian and Pospichal, Bernhard and R{\"o}ber, Niklas and Scheck, Leonhard and Seifert, Axel and Seifert, Patric and Senf, Fabian and Siligam, Pavan and Simmer, Clemens and Steinke, Sandra and Stevens, Bjorn and Wapler, Kathrin and Weniger, Michael and Wulfmeyer, Volker and Z{\"a}ngl, G{\"u}nther and Zhang, Dan and Quaas, Johannes}, title = {Large-eddy simulations over Germany using ICON: a comprehensive evaluation}, volume = {143}, journal = {Quarterly Journal of the Royal Meteorological Society}, number = {702}, doi = {10.1002/qj.2947}, pages = {69 -- 100}, year = {2017}, abstract = {Large-eddy simulations (LES) with the new ICOsahedral Non-hydrostatic atmosphere model (ICON) covering Germany are evaluated for four days in spring 2013 using observational data from various sources. Reference simulations with the established Consortium for Small-scale Modelling (COSMO) numerical weather prediction model and further standard LES codes are performed and used as a reference. This comprehensive evaluation approach covers multiple parameters and scales, focusing on boundary-layer variables, clouds and precipitation. The evaluation points to the need to work on parametrizations influencing the surface energy balance, and possibly on ice cloud microphysics. The central purpose for the development and application of ICON in the LES configuration is the use of simulation results to improve the understanding of moist processes, as well as their parametrization in climate models. The evaluation thus aims at building confidence in the model's ability to simulate small- to mesoscale variability in turbulence, clouds and precipitation. The results are encouraging: the high-resolution model matches the observed variability much better at small- to mesoscales than the coarser resolved reference model. In its highest grid resolution, the simulated turbulence profiles are realistic and column water vapour matches the observed temporal variability at short time-scales. Despite being somewhat too large and too frequent, small cumulus clouds are well represented in comparison with satellite data, as is the shape of the cloud size spectrum. Variability of cloud water matches the satellite observations much better in ICON than in the reference model. In this sense, it is concluded that the model is fit for the purpose of using its output for parametrization development, despite the potential to improve further some important aspects of processes that are also parametrized in the high-resolution model.}, language = {en} } @misc{FischerSchuetteDeuflhardetal.2001, author = {Fischer, Alexander and Sch{\"u}tte, Christof and Deuflhard, Peter and Cordes, Frank}, title = {Hierarchical Uncoupling-Coupling of Metastable Conformations}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-6296}, number = {01-03}, year = {2001}, abstract = {Uncoupling-coupling Monte Carlo (UCMC) combines uncoupling techniques for finite Markov chains with Markov chain Monte Carlo methodology. UCMC aims at avoiding the typical metastable or trapping behavior of Monte Carlo techniques. From the viewpoint of Monte Carlo, a slowly converging long-time Markov chain is replaced by a limited number of rapidly mixing short-time ones. Therefore, the state space of the chain has to be hierarchically decomposed into its metastable conformations. This is done by means of combining the technique of conformation analysis as recently introduced by the authors, and appropriate annealing strategies. We present a detailed examination of the uncoupling-coupling procedure which uncovers its theoretical background, and illustrates the hierarchical algorithmic approach. Furthermore, application of the UCMC algorithm to the \$n\$-pentane molecule allows us to discuss the effect of its crucial steps in a typical molecular scenario.}, language = {en} }