Publikationen

@article{Lintermann2020c,
title = {Lattice–Boltzmann simulations for complex geometries on high-performance computers},
author = {Lintermann, Andreas and Schröder, Wolfgang },
url = {http://link.springer.com/10.1007/s13272-020-00450-1},
doi = {10.1007/s13272-020-00450-1},
isbn = {1869-5582},
year = {2020},
date = {2020-05-13},
journal = {CEAS Aeronautical Journal},
abstract = {Complex geometries pose multiple challenges to the field of computational fluid dynamics. Grid generation for intricate objects is often difficult and requires accurate and scalable geometrical methods to generate meshes for large-scale computations. Such simulations, furthermore, presume optimized scalability on high-performance computers to solve high-dimensional physical problems in an adequate time. Accurate boundary treatment for complex shapes is another issue and influences parallel load-balance. In addition, large serial geometries prevent efficient computations due to their increased memory footprint, which leads to reduced memory availability for computations. In this paper, a framework is presented that is able to address the aforementioned problems. Hierarchical Cartesian boundary-refined meshes for complex geometries are obtained by a massively parallel grid generator. In this process, the geometry is parallelized for efficient computation. Simulations on large-scale meshes are performed by a high-scaling lattice–Boltzmann method using the second-order accurate interpolated bounce-back boundary conditions for no-slip walls. The method employs Hilbert decompositioning for parallel distribution and is hybrid MPI/OpenMP parallelized. The parallel geometry allows to speed up the pre-processing of the solver and massively reduces the local memory footprint. The efficiency of the computational framework, the application of which to, e.g., subsonic aerodynamic problems is straightforward, is shown by simulating clearly different flow problems such as the flow in the human airways, in gas diffusion layers of fuel cells, and around an airplane landing gear configuration},
keywords = {Airway, Computational Fluid Dynamics, High performance computing, Large-Scale Simulation Data, Lattice-Boltzmann method},
pubstate = {published},
tppubtype = {article}
}

@article{Lintermann2020a,
title = {Zonal Flow Solver (ZFS): a highly efficient multi-physics simulation framework},
author = {Lintermann, Andreas and Meinke, Matthias and Schröder, Wolfgang},
url = {https://www.tandfonline.com/doi/full/10.1080/10618562.2020.1742328},
doi = {10.1080/10618562.2020.1742328},
issn = {1061-8562},
year = {2020},
date = {2020-03-01},
journal = {International Journal of Computational Fluid Dynamics},
pages = {1-28},
abstract = {Multi-physics simulations are at the heart of today's engineering applications. The trend is towards more realistic and detailed simulations, which demand highly resolved spatial and temporal scales of various physical mechanisms to solve engineering problems in a reasonable amount of time. As a consequence, numerical codes need to run efficiently on high-performance computers. Therefore, the frame- work Zonal Flow Solver (ZFS) featuring lattice-Boltzmann, finite-volume, discontinuous Galerkin, level set, and Lagrange solvers, has been developed. The solvers can be combined to simulate, e.g., quasi-incompressible and compressible flow, aeroacoustics, moving boundaries, and particle dynamics. In this manuscript, the multi-physics implementation of the coupling mechanisms are presented. The parallelization approach, the involved solvers, and their scalability on state-of-the-art heterogeneous high-performance computers are discussed. Various multi-physics applications complement the discussion. The results show ZFS to be a highly efficient and flexible multi-purpose tool that can be used to solve varying classes of coupled problems.},
keywords = {Code coupling, Hierarchical Cartesian meshes, High-performance computing, Multi-physics simulations, Performance analysis},
pubstate = {published},
tppubtype = {article}
}

@article{AkmPrillVogt2019,
title = {Nasal valve elastography: quantitative determination of the mobility of the nasal valve},
author = {Liga Akmenkalne and Matthias Prill and Klaus Vogt},
editor = {Rhinology online},
url = {https://www.rhinologyonline.org/Rhinology_online_issues/manuscript_50.pdf},
doi = {http://doi.org/10.4193/RHINOL/18.086},
year = {2019},
date = {2019-05-25},
journal = {Rhinology online},
volume = {Vol 2},
pages = {81 - 86},
abstract = {Background: The nasal valve area is the narrowest region of the entire upper airway. Numerous procedures and spreader devices are published to widen the nasal valve or to stabilize it, but the indications are based only on the surgeon’s experience.
Methods: In 30 healthy volunteers the deflection of elastic steel elements touching the lower nasal side at its deepest point was precisely measured by means of strain gauges. The deflection was calibrated by standard calibration devices. A special 4-phase-rhinomanometer (4RHINO/ Rhinolab/Germany) with a protective face mask allowed simultaneous measurements of the airflow and differential pressure. All signals were recorded simultaneously on both sides. The measurements have been carried out as unilateral measurements according to anterior rhinomanometry.
Results: Surprisingly the lateral nasal wall is already moving during quiet breathing. The airflow and its acceleration as well as the pressure difference generating a complete closure of the nose can be determined and has expectedly a high variance between individuals.
Conclusions: The elastography confirms the loops in 4-phase-rhinomanometry as symptomatic for the nasal valve elongation and will after developing as medical product allow the systematic quantitative measurement of the influence of the nasal valve on the nasal air stream. },
keywords = {elastography, lateral nasal wall, nasal valve, rhinoplasty, surgical indication},
pubstate = {published},
tppubtype = {article}
}

@article{Age,
title = {Relationships among nasal resistance, age and anthropometric parameters of the nose during growth},
author = {Kaspars Peksis and Juliane Unger and Santa Paulauska and Aja Emsina and Martins Blumbergs and Klaus Vogt and Klaus-Dieter Wernecke},
url = {https://rhinodiagnost.eu/wp-content/uploads/2018/10/GrowingAgeRelPublication.pdf},
doi = {http://doi.org/10.4193/RHINOL/18.032},
year = {2018},
date = {2018-09-15},
journal = {Rhinology Online},
volume = {Vol 1},
pages = {112 - 121},
abstract = {Background: Children generally have a higher nasal resistance than adults. Growth changes the size and different anthropometric parameters of the nose. Logarithmic effective resistance and logarithmic vertex resistance were introduced as physically correct parameters for nasal obstruction. The previously published classification of obstruction derived from 36,500 measurements is missing data for patients aged 7 to 19 years.
Methodology: Rhinomanometry was performed before and after decongestion with 9 different anthropometric measurements in 225 children and adolescents. Correlations among age, anthropometric measurements, and logarithmic effective and vertex resistance were determined for both sexes, and regressions were calculated.
Results: The highest correlations with the resistance values were found between age, lateral nasal length, and logarithmic effective resistance. A highly significant linear regression between age and logarithmic effective resistance was also found. This was used for adaption of the classification of obstruction in adults to growing patients. The resistance of the nasal airways at the age of 7 years was about twice that in adults.
Conclusions: The linear regression equations can be used to suborder obstructions measured by four-phase rhinomanometry into classes for estimation of their severity according to age.
},
keywords = {4-phase rhinomanometry, classification, growing age, nasal obstruction},
pubstate = {published},
tppubtype = {article}
}

@article{KochFlip18,
title = {Flipped Classroom – A Flexible Way of Teaching Technology Usage for Diagnostics in the Medical Subdomain ENT},
author = {Walter Koch and Jochen Schachenreiter and Klaus Vogt and Gerda Koch},
editor = {Journal on Systemics, Cybernetics and Informatics: JSCI},
url = {http://www.iiisci.org/journal/sci/FullText.asp?var=&id=ZA061ZN18},
isbn = {1690-4524 (Online)},
year = {2018},
date = {2018-05-04},
journal = {Journal on Systemics, Cybernetics and Informatics: JSCI},
volume = {16},
number = {1},
pages = {60-64},
abstract = {A special problem area which ENT-Head/Neck (ENT: Ear-Nose-Throat) surgery specialists have to deal with is the air flow in the nasal cavities and paranasal sinuses. It is a burning problem to extend the morphological diagnostic by detailed functional analysis, i.e. the visualization of the nasal air stream and the physical analysis of its energetic. The simulation of the airflow via CFD (Computational Fluid Dynamics) is nowadays gaining importance for diagnostics, and the visualization and simulation of airflows from the nostrils to the nasal pharynx afford in first place a precise and high quality 3D reconstruction of the nasal cavities. But the successive validation and interpretation of CFD simulation results is a challenge for non CFD specialists. The introduction of these new technologies requires special education and training for students as well as for medical experts in order to learn how to use and handle different tools and methods when preparing a surgery. “Flipped classroom”, a type of blended learning, is a preferred method for supporting knowledge transfer not only to students and employees but also among all kind of different members within organizations.},
keywords = {ENT, Flipped Classroom, Functional Endoscopic Sinus Surgery, Modern Learning Environments},
pubstate = {published},
tppubtype = {article}
}

@article{Kim2018,
title = {Assessment of changes in the nasal airway after nonsurgical miniscrew-assisted rapid maxillary expansion in young adults},
author = {Kim, Soo-Yeon and Park, Young-Chel and Lee, Kee-Joon and Lintermann, Andreas and Han, Sang-Sun and Yu, Hyung-Seog and Choi, Yoon Jeong},
editor = {The Angle Orthodontist},
url = {https://rhinodiagnost.eu/wp-content/uploads/2018/04/092917-656.1_Kim2018.pdf},
doi = {www.angle.org/doi/10.2319/092917-656.1},
issn = {0003-3219},
year = {2018},
date = {2018-03-23},
journal = {The Angle Orthodontist},
pages = {092917--656.1},
abstract = {Objectives: To evaluate changes in the volume and cross-sectional area of the nasal airway before and 1 year after nonsurgical miniscrew-assisted rapid maxillary expansion (MARME) in young adults.
Materials and Methods: Fourteen patients (mean age, 22.7 years; 10 women, four men) with a transverse discrepancy who underwent cone beam computed tomography before (T0), immediately after (T1), and 1 year after (T2) expansion were retrospectively included in this study. The volume of the nasal cavity and nasopharynx and the cross-sectional area of the anterior, middle, and posterior segments of the nasal airway were measured and compared among the three timepoints using paired t-tests.
Results: The volume of the nasal cavity showed a significant increase at T1 and T2 (P < .05), while that of the nasopharynx increased only at T2 (P < .05). The anterior and middle cross-sectional areas significantly increased at T1 and T2 (P < .05), while the posterior cross-sectional area showed no significant change throughout the observation period (P > .05).
Conclusions: The results demonstrate that the volume and cross-sectional area of the nasal cavity increased after MARME and were maintained at 1 year after expansion. Therefore, MARME may be helpful in expanding the nasal airway.
},
keywords = {Airway, MARME, Nasal cavity flows, Nasal respiration, Respiratory Flow Computation},
pubstate = {published},
tppubtype = {article}
}

@article{vogtriga18,
title = {The new agreement of the international RIGA consensus conference on nasal airway function tests},
author = {Klaus Vogt and Gregor Bachmann-Harildstad and Andreas Lintermann and Alina Nechyporenko and Franz Peters and Klaus-Dieter Wernecke
},
editor = {Rhinology International},
url = {http://rhinodiagnost.eu/wp-content/uploads/2018/01/Rhinology_manuscript_1777.pdf, The new agreement of the international RIGA consensus conference on nasal airway function tests},
doi = {https://doi.org/10.4193/Rhino17.084},
year = {2018},
date = {2018-01-23},
journal = {Rhinology},
volume = {56},
abstract = {The report reflects an agreement based on the consensus conference of the International Standardization Committee on the Objective Assessment of the Nasal Airway in Riga, 2nd Nov. 2016.
The aim of the conference was to address the existing nasal airway function tests and to take into account physical, mathematical and technical correctness as a base of international standardization as well as the requirements of the Council Directive 93/42/EEC of 14 June 1993 concerning medical devices.
Rhinomanometry, acoustic rhinometry, peak nasal inspiratory flow, Odiosoft-Rhino, optical rhinometry, 24-h measurements, computational fluid dynamics, nasometry and the mirrow test were evaluated for important diagnostic criteria, which are the precision of the equipment including calibration and the software applied; validity with sensitivity, specificity, positive and negative predictive values, reliability with intra-individual and inter-individual reproducibility and responsiveness in clinical studies.
For rhinomanometry, the logarithmic effective resistance was set as the parameter of high diagnostic relevance. In acoustic rhinometry, the area of interest for the minimal cross-sectional area will need further standardization. Peak nasal inspiratory flow is a reproducible and fast test, which showed a high range of mean values in different studies. The state of the art with computational fluid dynamics for the simulation of the airway still depends on high performance computing hardware and will, after standardization of the software and both the software and hardware for imaging protocols, certainly deliver a better understanding of the nasal airway flux.},
keywords = {diagnosis, nasal cavity, nasal mucosa, nasal septum, physiology},
pubstate = {published},
tppubtype = {article}
}

@article{Lintermann2017FTaC,
title = {A Hierarchical Numerical Journey through the Nasal Cavity: From Nose-Like Models to Real Anatomies},
author = {Lintermann, Andreas and Schröder, Wolfgang},
editor = {Springer Netherlands},
url = {http://rhinodiagnost.eu/wp-content/uploads/2017/12/paper_FTAC_SI_health_Lintermann.pdf, A Hierarchical Numerical Journey through the Nasal Cavity: From Nose-Like Models to Real Anatomies},
doi = {10.1007/s10494-017-9876-0},
issn = {1386-6184},
year = {2017},
date = {2017-12-20},
issuetitle = {special issue "CFD in Health"},
journal = {Flow, Turbulence and Combustion},
abstract = {The immense increase of computational power in the past decades led to an evolution of numerical simulations in all kind of engineering applications. New developments in medical technologies in rhinology employ computational fluid dynamics methods to explore pathologies from a fluid-mechanics point of view. Such methods have grown mature and are about to enter daily clinical use to support doctors in decision making. In light of the importance of effective respiration on patient comfort and health care costs, individualized simulations ultimately have the potential to revolutionize medical diagnosis, drug delivery, and surgery planning. The present article reviews experiments, simulations, and algorithmic approaches developed at RWTH Aachen University that have evolved from fundamental physical analyses using nose-like models to patient-individual analyses based on realistic anatomies and high resolution computations in hierarchical manner.},
keywords = {Digital particle image velocimetry, Finite volume method, High performance computing, Lattice-Boltzmann method, Nasal cavity flows},
pubstate = {published},
tppubtype = {article}
}

@article{Göbbert2017exa,
title = {Flow predictions for your nose},
author = {Göbbert, Jens Henrik},
editor = {Forschungszentrum Jülich GmbH},
url = {http://exascale-news.de/en/2017/index/#!/Flow-Predictions-for-Your-Nose, Flow predictions for your nose (Englische Version online)

http://rhinodiagnost.eu/wp-content/uploads/2017/11/exascale_nl_03_2017.pdf, Strömungsvorhersage für die Nase (Deutsche Version)
},
year = {2017},
date = {2017-11-09},
urldate = {2017-11-09},
journal = {Exascale-Newsletter},
volume = {3},
pages = {3},
institution = {Forschungszentrum Jülich GmbH},
keywords = {Computational Fluid Dynamics, High performance computing, Höchstleistungsrechner, Medizin, Nasal respiration, Strömungssimulation},
pubstate = {published},
tppubtype = {article}
}

@article{Lintermann2017,
title = {Strömende Bits und Bytes - Zusammenspiel von Höchstleistungsrechnern und Medizin},
author = {Lintermann, Andreas},
editor = {RWTH Aachen University},
url = {http://rhinodiagnost.eu/wp-content/uploads/2017/10/RWTH_Themenheft_Lintermann-1.pdf, Strömende Bits und Bytes - Zusammenspiel von Höchstleistungsrechnern und Medizin},
year = {2017},
date = {2017-09-01},
journal = {RWTH Themenheft},
address = {RWTH Aachen University, Aachen, Germany},
school = {RWTH Aachen University},
abstract = {Respiration is an essential physiological functionality of the human organism and is responsible for supplying the body with oxygen. The nasal cavity takes care of olfaction and degustation, filters fine dust from the air as well as moisturizes and tempers the air. Therefore, it is indispensable in respiration, and a degradation of only one or a few functionalities leads to discomfort or further pathologies. In the profile area Computational Science {&} Engineering (CompSE), human respiration is analyzed by means of highly-resolved numerical simulations that, due to the large problem sizes, can only be executed on supercomputers. Complaints in nasal respiration, the development of chronic airway diseases, a reduction of olfaction and degustation, particle deposition behavior and filtering mechanisms of the nasal cavity, air conditioning capability, and a fundamental understanding of the physics of human respiration are at the core of the research. The following article gives an overview of the methodologies employed by the group, current results, and the challenges engineers, computer scientists, and medical specialists have to face in the future to reach the goal of personalized medical treatment.},
keywords = {Höchstleistungsrechner, Medizin, Strömungssimulation},
pubstate = {published},
tppubtype = {article}
}

@article{RhinoAll,
title = {Rhinodiagnost - Morphological and functional precision diagnostics of nasal cavities},
author = {Lintermann, Andreas and Göbbert, Jens Henrik and Vogt, Klaus and Koch, Walter and Hetzel, Alexander},
editor = {Gauss Center for Supercomputing (GCS), High-Perfomance Computing Center Stuttart (HLRS)},
url = {http://rhinodiagnost.eu/wp-content/uploads/2017/11/InSiDE-Innovatives-Supercomputing-in-Deutschland-2017-Rhinodiagnost-Morphological-and-functional-precision-diagnostics-of-nasal-c.pdf, Rhinodiagnost - Morphological and functional precision diagnostics of nasal cavities},
year = {2017},
date = {2017-08-31},
journal = {InSiDE, Innovatives Supercomputing in Deutschland},
volume = {15},
number = {2},
pages = {106-109},
keywords = {Computational Fluid Dynamics, Diagnostics, In-situ computational steering, Nasal respiration, Rhinology, Rhinomanometry},
pubstate = {published},
tppubtype = {article}
}