@misc{MoualeuNgangueRoeblitzEhrigetal.2013, author = {Moualeu-Ngangue, Dany Pascal and R{\"o}blitz, Susanna and Ehrig, Rainald and Deuflhard, Peter}, title = {Parameter Identification for a Tuberculosis Model in Cameroon}, issn = {1438-0064}, doi = {10.1371/journal.pone.0120607}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-43087}, year = {2013}, abstract = {A deterministic model of tuberculosis in sub-Saharan Africa in general and Cameroon in particular including lack of access to the treatment and weak diagnose capacity is designed and analyzed with respect to its transmission dynamics. The model includes both frequency- and density-dependent transmissions. It is shown that the model is mathematically well-posed and epidemiologically reasonable. Solutions are non-negative and bounded whenever the initial values are non-negative. A sensitivity analysis of model parameters is performed and most sensitive parameters of the model are identified using a state-of-the-art Gauss-Newton Method. In particular, parameters representing the proportion of individuals having access to medical facilities have a large impact on the dynamics of the disease. It has been shown that an increase of these parameter values over the time can significantly reduce the disease burden in the population within the next 15 years.}, language = {en} } @misc{MoualeuNgangueWeiserEhrigetal.2013, author = {Moualeu-Ngangue, Dany Pascal and Weiser, Martin and Ehrig, Rainald and Deuflhard, Peter}, title = {Optimal control for a tuberculosis model with undetected cases in Cameroon}, issn = {1438-0064}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-43142}, year = {2013}, abstract = {This paper considers the optimal control of tuberculosis through education, diagnosis campaign and chemoprophylaxis of latently infected. A mathematical model which includes important components such as undiagnosed infectious, diagnosed infectious, latently infected and lost-sight infectious is formulated. The model combines a frequency dependent and a density dependent force of infection for TB transmission. Through optimal control theory and numerical simulations, a cost-effective balance of two different intervention methods is obtained. Seeking to minimize the amount of money the government spends when tuberculosis remain endemic in the Cameroonian population, Pontryagin's maximum principle is used to characterize the optimal control. The optimality system is derived and solved numerically using the forward-backward sweep method (FBSM). Results provide a framework for designing cost-effective strategies for diseases with multiple intervention methods. It comes out that combining chemoprophylaxis and education, the burden of TB can be reduced by 80 \% in 10 years}, language = {en} } @incollection{EhrigNowakOeverdiecketal.1999, author = {Ehrig, Rainald and Nowak, Ulrich and Oeverdieck, Lars and Deuflhard, Peter}, title = {Advanced Extrapolation Methods for Large Scale Differential Algebraic Problems}, volume = {8}, booktitle = {High Performance Scientific and Engineering Computing}, editor = {H.-J. Bungartz, F.}, publisher = {Springer Verlag}, pages = {233 -- 244}, year = {1999}, language = {en} } @article{EhrigOfenlochSchaberetal.2002, author = {Ehrig, Rainald and Ofenloch, O. and Schaber, Karlheinz and Deuflhard, Peter}, title = {Modelling and Simulation of Aerosol Formation by Heterogeneous Nucleation in Gas-Liquid Contact Devices}, volume = {57}, journal = {Chem.Eng.Sci.}, number = {7}, pages = {1151 -- 1163}, year = {2002}, language = {en} } @inproceedings{EhrigNowakDeuflhard1998, author = {Ehrig, Rainald and Nowak, Ulrich and Deuflhard, Peter}, title = {Massively Parallel Simulation in Chemical Engineering by Extrapolation Algorithms}, booktitle = {Procs. 16th International Workshop on Distributed Data Processing, Novosibirsk, Russia}, editor = {Khoroshevsky, V.}, pages = {1 -- 6}, year = {1998}, language = {en} } @article{KoerberSchaberEhrigetal.1998, author = {Koerber, Jens and Schaber, Karlheinz and Ehrig, Rainald and Deuflhard, Peter}, title = {Modelling and simulation of aerosol formation in absorption processes}, volume = {29}, journal = {J. Aerosol Sci}, pages = {579 -- 580}, year = {1998}, language = {en} } @article{SchaberKoerberOfenlochetal.2002, author = {Schaber, Karlheinz and Koerber, Jens and Ofenloch, O. and Ehrig, Rainald and Deuflhard, Peter}, title = {Aerosol Formation in Gas-Liquid Contact Devices- Nucleation, Growth and Particle Dynamics}, volume = {57}, journal = {Chem.Eng.Sci.}, pages = {4345 -- 4356}, year = {2002}, language = {en} } @article{SchaberOfenlochEhrigetal.2004, author = {Schaber, Karlheinz and Ofenloch, Oliver and Ehrig, Rainald and Deuflhard, Peter}, title = {Aerosolbildung in Gas/Fl{\"u}ssigkeits-Kontaktapparaten - Modellierungsstrategien und Simulation}, volume = {76}, journal = {Chemie Ingenieur Technik}, number = {9}, pages = {1358 -- 1359}, year = {2004}, language = {en} } @article{WixSchaberOfenlochetal.2007, author = {Wix, A. and Schaber, Karlheinz and Ofenloch, O. and Ehrig, Rainald and Deuflhard, Peter}, title = {Simulation of Aerosol Formation in Gas-Liquid Contact Devices}, volume = {194}, journal = {Chem. Eng. Comm.}, pages = {565 -- 577}, year = {2007}, language = {en} } @misc{EhrigNowakDeuflhard1997, author = {Ehrig, Rainald and Nowak, Ulrich and Deuflhard, Peter}, title = {Massively Parallel Linearly-Implicit Extrapolation Algorithms as a Powerful Tool in Process Simulation.}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-3127}, number = {SC-97-43}, year = {1997}, abstract = {We study the parallelization of linearly--implicit extrapolation codes for the solution of large scale PDE systems and differential algebraic equations on distributed memory machines. The main advantage of these algorithms is that they enable adapativity both in time and space. Additive Krylov--Schwarz methods yield high parallel perfomance for such extrapolation methods. Our approach combines a slightly overlapping domain decomposition together with a polynomial block Neumann preconditioner and a reduced system technique. Furthermore we get important advantages through the explicit computation of the matrix--products of the preconditioner and the matrix of the linear system. The parallel algorithms exhibit scalability up to 64 processors already for medium--sized test problems. We show that the codes are really efficient in large application systems for chemical engineering problems.}, language = {en} }