@inproceedings {INPROC-2003-41,
   author = {Ralf-Peter Mundani and Hans-Joachim Bungartz and Ernst Rank and Richard Romberg and Andreas Niggl},
   title = {{Efficient Algorithms for Octree-Based Geometric Modelling}},
   booktitle = {Proceedings of the Ninth International Conference on Civil and Structural Engineering Computing: CC '03; Egmond aan Zee, The Netherlands, September 2-4, 2003},
   editor = {B.H.V. Topping},
   publisher = {Civil-Comp Press},
   institution = {University of Stuttgart, Faculty of Computer Science, Electrical Engineering, and Information Technology, Germany},
   type = {Conference Paper},
   month = {September},
   year = {2003},
   keywords = {octrees; volume-oriented geometric modelling; consistency checks; hierarchical data structures; on-the-fly generation; embedded simulation},
   language = {English},
   cr-category = {I.3.5 Computational Geometry and Object Modeling,
                   I.6.0 Simulation and Modeling General,
                   I.6.3 Simulation and Modeling Applications,
                   J.2 Physical Sciences and Engineering,
                   J.6 Computer-Aided Engineering},
   contact = {Ralf-Peter Mundani Ralf.Mundani@ipvs.uni-stuttgart.de},
   department = {University of Stuttgart, Institute of Parallel and Distributed Systems, Simulation of Large Systems},
   abstract = {Dealing with surface-oriented models - e.g. B-Rep models - is very popular and
      appropriate for many applications. They can be read by most CAD programs and
      they provide all freedom of modelling. Concerning a lot of other tasks -
      consistency checks, collision detection, structural analysis, flow simulation,
      e.g. - these models become difficult to handle, and a volume-oriented model has
      to be derived from the existing surface-oriented one. Hierarchical
      volume-oriented models, represented by octrees for example, provide an easy
      access to solve the latter tasks with respect to their spatial decomposition of
      the underlying geometry. This paper deals with fast and efficient algorithms to
      generate and process octrees - even on-the-fly - from surface-oriented models
      for applications in civil engineering. Encoding these octrees as binary streams
      makes them suitable to get multiplexed with other octree-coded objects or for
      the usage in pipe-like constructs.
      
      Conventional algorithms for octree generation or processing don't exploit the
      full potential of these structures. In spite of the principal advantages of
      octrees concerning complexity, objects of a higher resolution typically still
      entail too high run-time and memory requirements. Usually, an expensive
      floating-point-based decision whether or not to refine the structure has to be
      taken in each voxel (cell) successively. In our approach, instead, the
      refinement decision is done by a simple parameter comparison of plane
      equations, avoiding all these costs.
      
      By treating each face of the surface-oriented model as a plane that divides the
      whole space into two half spaces - inside and outside -, the volume-oriented
      model can be built from intersecting all inside-attributed half spaces. The
      steps for generating an octree presentation for each corresponding plane,
      intersecting these octrees, and encoding the result as a binary stream can be
      done at once - thus, the octree generation is free of any redundant
      calculations, and the overall memory requirements are reduced to a minimum due
      to the usage of stacks. The highest gain can be achieved in run-time, e.g. an
      octree generation for an average geometry with more than 1.5 billion voxels can
      be done in best time on a standard PC. Several of these binary streams can be
      multiplexed to perform further Boolean or more sophisticated operations (e.g.
      collision detection), while one always has the choice to perform this
      operations on-the-fly or to perform consecutive operations - like with Unix
      pipes - on binary streams written to the hard disk.
      
      One target application of this method deals with consistency checks for CAD
      models in the scope of simplifying and unifying planning processes in civil
      engineering. Before a connection model for structural analysis is created out
      of an (Eurostep) IFC model, any modelling errors (geometric inconsistencies) -
      wrong intersections or gaps between parts of the model - can be detected fast
      and easily. Hence, this proceeding enables us to obtain a reliable
      volume-oriented attributed model that can serve for numerical simulations as
      well as to determine relations between parts of the model to ensure global
      consistency, which brings us one step closer to the long-term objective of
      completely embedded simulation processes.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2003-41&engl=1}
}

@article {ART-2003-08,
   author = {Hans-Joachim Bungartz},
   title = {{Sparse Grids - Tackling the Curse of Dimension}},
   journal = {gacm Report},
   publisher = {gacm},
   volume = {2003},
   number = {2},
   pages = {16--21},
   type = {Article in Journal},
   month = {January},
   year = {2003},
   language = {English},
   cr-category = {G.1 Numerical Analysis},
   contact = {Hans-Joachim Bungartz bungartz@ipvs.uni-stuttgart.de},
   department = {University of Stuttgart, Institute of Parallel and Distributed Systems, Simulation of Large Systems},
   abstract = {no abstract available},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=ART-2003-08&engl=1}
}

@article {ART-2003-07,
   author = {Hans-Joachim Bungartz},
   title = {{Computational Science and Engineering: a new master's program at the Technische Universit{\"a}t M{\"u}nchen}},
   journal = {Future Generation Computer Systems},
   address = {Amsterdam},
   publisher = {Elsevier B.V.},
   volume = {19},
   number = {8},
   pages = {1267--1274},
   type = {Article in Journal},
   month = {November},
   year = {2003},
   language = {English},
   cr-category = {K.3 Computers and Education},
   contact = {Hans-Joachim Bungartz bungartz@ipvs.uni-stuttgart.de},
   department = {University of Stuttgart, Institute of Parallel and Distributed Systems, Simulation of Large Systems},
   abstract = {In the winter semester of 2001/2002, the Technische Universit{\"a}t M{\"u}nchen (TUM)
      started its new master's program computational science and engineering (CSE) as
      a joint initiative of seven faculties. It is the objective of this contribution
      to outline the underlying ideas and concepts and their curricular
      implementation as well as to emphasize some features that are probably
      non-standard in other comparable programs.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=ART-2003-07&engl=1}
}

@article {ART-2003-06,
   author = {Hans-Joachim Bungartz and Stefan Dirnstorfer},
   title = {{Multivariate quadrature on adaptive sparse grids}},
   journal = {Computing},
   address = {New York},
   publisher = {Springer},
   volume = {71},
   number = {1},
   pages = {89--114},
   type = {Article in Journal},
   month = {September},
   year = {2003},
   isbn = {0010-485X},
   language = {English},
   cr-category = {G.1 Numerical Analysis,
                   I.1 Symbolic and Algebraic Manipulation},
   department = {University of Stuttgart, Institute of Parallel and Distributed Systems, Simulation of Large Systems},
   abstract = {In this paper, we study the potential of adaptive sparse grids for multivariate
      numerical quadrature in the moderate or high dimensional case, i.e. for a
      number of dimensions beyond three and up to several hundreds. There,
      conventional methods typically suffer from the curse of dimension or are
      unsatisfactory with respect to accuracy. Our sparse grid approach, based upon a
      direct higher order discretization on the sparse grid, overcomes this dilemma
      to some extent, and introduces additional flexibility with respect to both the
      order of the 1 D quadrature rule applied (in the sense of Smolyak's tensor
      product decomposition) and the placement of grid points. The presented
      algorithm is applied to some test problems and compared with other existing
      methods.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=ART-2003-06&engl=1}
}

@inbook {INBOOK-2003-17,
   author = {Hans-Joachim Bungartz and Miriam Mehl},
   title = {{Biofilms in Wastewater Treatment: An Interdisciplinary Approach}},
   series = {Beyond models: Requirements and chances of computational biofilms},
   publisher = {IWA Publishing},
   pages = {60--87},
   type = {Article in Book},
   month = {January},
   year = {2003},
   language = {English},
   cr-category = {I.6 Simulation and Modeling},
   department = {University of Stuttgart, Institute of Parallel and Distributed Systems, Simulation of Large Systems},
   abstract = {The central theme of the book is the flow of information from experimental
      approaches in biofilm research to simulation and modeling of complex wastewater
      systems. Probably the greatest challenge in wastewater research lies in using
      the methods and the results obtained in one scientific discipline to design
      intelligent experiments in other disciplines, and eventually to improve the
      knowledge base the practitioner needs to run wastewater treatment plants. The
      purpose of Biofilms in Wastewater Treatment is to provide engineers with the
      knowledge needed to apply the new insights gained by researchers. The authors
      provide an authoritative insight into the function of biofilms on a technical
      and on a lab-scale, cover some of the exciting new basic microbiological and
      wastewater engineering research involving molecular biology techniques and
      microscopy, and discuss recent attempts to predict the development of biofilms.
      This book is divided into 3 sections: Modeling and Simulation; Architecture,
      Population Structure and Function; and From Fundamentals to Practical
      Application, which all start with a scientific question. Individual chapters
      attempt to answer the question and present different angles of looking at
      problems. In addition there is an extensive glossary to familiarize the
      non-expert with unfamiliar terminology used by microbiologists and
      computational scientists.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INBOOK-2003-17&engl=1}
}

@inbook {INBOOK-2003-16,
   author = {Hans-Joachim Bungartz and M. Kuehn and Miriam Mehl and S. Wuertz},
   title = {{Polymer and Cell Dynamics - Multiscale Modelling and Numerical Simulations}},
   series = {Space- and time-resolved simulations of processes in biofilm systems on a microscale},
   address = {Basel},
   publisher = {Birkh{\"a}user},
   pages = {175--188},
   type = {Article in Book},
   month = {October},
   year = {2003},
   isbn = {376-436-924-8},
   language = {German},
   cr-category = {I.6 Simulation and Modeling},
   department = {University of Stuttgart, Institute of Parallel and Distributed Systems, Simulation of Large Systems},
   abstract = {leer},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INBOOK-2003-16&engl=1}
}

@inbook {INBOOK-2003-08,
   author = {H.-J. Bungartz and M. Mehl},
   title = {{Beyond models: Requirements and chances of computational biofilms}},
   series = {Biofilms in Wastewater Treatment: An Interdisciplinary Approach},
   publisher = {IWA Publishing},
   pages = {60--87},
   type = {Article in Book},
   month = {January},
   year = {2003},
   language = {English},
   cr-category = {J.3 Life and Medical Sciences},
   contact = {Hans-Joachim Bungartz bungartz@ipvs.uni-stuttgart.de},
   department = {University of Stuttgart, Institute of Parallel and Distributed Systems, Simulation of Large Systems},
   abstract = {no abstract available},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INBOOK-2003-08&engl=1}
}

@inbook {INBOOK-2003-07,
   author = {Hans-Joachim Bungartz and M. Kuehn and M. Mehl and S. Wuertz},
   title = {{Space- and time-resolved simulations of processes in biofilm systems on a microscale}},
   series = {Polymer and Cell Dynamics - Multiscale Modelling and Numerical Simulations},
   address = {Basel},
   publisher = {Birkh{\"a}user},
   pages = {175--188},
   type = {Article in Book},
   month = {October},
   year = {2003},
   isbn = {3764369248},
   language = {English},
   cr-category = {J.3 Life and Medical Sciences,
                   I.6 Simulation and Modeling},
   contact = {Hans-Joachim Bungartz bungartz@ipvs.uni-stuttgart.de},
   department = {University of Stuttgart, Institute of Parallel and Distributed Systems, Simulation of Large Systems},
   abstract = {New experimental and analytical techniques like confocal laser scanning
      microscopy (CSLM) or the use of RNA-targeted probes have provided insight into
      the morphology, architecture, and function of biofilm cultures. The different
      observations made there suggest that more attention has to be paid to a
      detailed study of the microscale processes like flow and transport phenomena as
      well as to the development of the bofilm's primary components, i.e. microbial
      cells and extracellular polymeric substances (EPS). For that, numerical
      simulations are a promising approach. However, due to the large variety of
      different effects and influence factors, strong multiscale characteristics with
      respect to both time and space, and due to the need for an explicit high
      spatial resolution in order to capture the occurring changes of the underlying
      geometry because of biomass growth, for example, 3D simulations have hardly
      been tackled so far. Actually, most existing simulation tools for biofilm
      systems are based on strongly simplified model assumptions that turned out to
      be not valid in general.
      
      In this work, we report on first steps towards microscale simulations of flow,
      transport, reactive, and growth processes in 3D biofilm geometries obtained
      from CLSM images of a small and defined monoculture biofilm setup. The basic
      framework is the finite volume CFD solver Nast++, to which transport equations
      (convection-diffusion in the fluid phase, diffusion-reaction in the biofilm)
      and the cellular automaton CAsim for capturing biomass growth are coupled. Some
      numerical results of realized simulations as well as strategies for an
      increased numerical efficiency are presented.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INBOOK-2003-07&engl=1}
}