@article{MortazaviRabczuk, author = {Mortazavi, Bohayra and Rabczuk, Timon}, title = {Multiscale modeling of heat conduction in graphene laminates}, series = {Carbon}, journal = {Carbon}, pages = {1 -- 7}, abstract = {Multiscale modeling of heat conduction in graphene laminates}, subject = {Angewandte Mathematik}, language = {en} } @article{IlyaniAkmarKramerRabczuk, author = {Ilyani Akmar, A.B. and Kramer, O. and Rabczuk, Timon}, title = {Multi-objective evolutionary optimization of sandwich structures: An evaluation by elitist non-dominated sorting evolution strategy}, series = {American Journal of Engineering and Applied Sciences}, journal = {American Journal of Engineering and Applied Sciences}, doi = {10.3844/ajeassp.2015.185.201}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20170418-31402}, pages = {185 -- 201}, abstract = {In this study, an application of evolutionary multi-objective optimization algorithms on the optimization of sandwich structures is presented. The solution strategy is known as Elitist Non-Dominated Sorting Evolution Strategy (ENSES) wherein Evolution Strategies (ES) as Evolutionary Algorithm (EA) in the elitist Non-dominated Sorting Genetic algorithm (NSGA-II) procedure. Evolutionary algorithm seems a compatible approach to resolve multi-objective optimization problems because it is inspired by natural evolution, which closely linked to Artificial Intelligence (AI) techniques and elitism has shown an important factor for improving evolutionary multi-objective search. In order to evaluate the notion of performance by ENSES, the well-known study case of sandwich structures are reconsidered. For Case 1, the goals of the multi-objective optimization are minimization of the deflection and the weight of the sandwich structures. The length, the core and skin thicknesses are the design variables of Case 1. For Case 2, the objective functions are the fabrication cost, the beam weight and the end deflection of the sandwich structures. There are four design variables i.e., the weld height, the weld length, the beam depth and the beam width in Case 2. Numerical results are presented in terms of Paretooptimal solutions for both evaluated cases.}, subject = {Optimierung}, language = {en} } @article{MortazaviPereiraJiangetal., author = {Mortazavi, Bohayra and Pereira, Luiz Felipe C. and Jiang, Jin-Wu and Rabczuk, Timon}, title = {Modelling heat conduction in polycrystalline hexagonal boron-nitride films}, series = {Scientific Reports}, journal = {Scientific Reports}, doi = {10.1038/srep13228}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20170425-31534}, abstract = {We conducted extensive molecular dynamics simulations to investigate the thermal conductivity of polycrystalline hexagonal boron-nitride (h-BN) films. To this aim, we constructed large atomistic models of polycrystalline h-BN sheets with random and uniform grain configuration. By performing equilibrium molecular dynamics (EMD) simulations, we investigated the influence of the average grain size on the thermal conductivity of polycrystalline h-BN films at various temperatures. Using the EMD results, we constructed finite element models of polycrystalline h-BN sheets to probe the thermal conductivity of samples with larger grain sizes. Our multiscale investigations not only provide a general viewpoint regarding the heat conduction in h-BN films but also propose that polycrystalline h-BN sheets present high thermal conductivity comparable to monocrystalline sheets.}, subject = {W{\"a}rmeleitf{\"a}higkeit}, language = {en} } @article{KumarSinghMishraetal., author = {Kumar, S. and Singh, I. and Mishra, B.K. and Rabczuk, Timon}, title = {Modeling and Simulation of Kinked Cracks by Virtual Node XFEM}, series = {Computer Methods in Applied Mechanics and Engineering}, journal = {Computer Methods in Applied Mechanics and Engineering}, pages = {1425 -- 1466}, abstract = {Modeling and Simulation of Kinked Cracks by Virtual Node XFEM}, subject = {Angewandte Mathematik}, language = {en} } @phdthesis{Jia, author = {Jia, Yue}, title = {Methods based on B-splines for model representation, numerical analysis and image registration}, doi = {10.25643/bauhaus-universitaet.2484}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20151210-24849}, school = {Bauhaus-Universit{\"a}t Weimar}, pages = {200}, abstract = {The thesis consists of inter-connected parts for modeling and analysis using newly developed isogeometric methods. The main parts are reproducing kernel triangular B-splines, extended isogeometric analysis for solving weakly discontinuous problems, collocation methods using superconvergent points, and B-spline basis in image registration applications. Each topic is oriented towards application of isogeometric analysis basis functions to ease the process of integrating the modeling and analysis phases of simulation. First, we develop reproducing a kernel triangular B-spline-based FEM for solving PDEs. We review the triangular B-splines and their properties. By definition, the triangular basis function is very flexible in modeling complicated domains. However, instability results when it is applied for analysis. We modify the triangular B-spline by a reproducing kernel technique, calculating a correction term for the triangular kernel function from the chosen surrounding basis. The improved triangular basis is capable to obtain the results with higher accuracy and almost optimal convergence rates. Second, we propose an extended isogeometric analysis for dealing with weakly discontinuous problems such as material interfaces. The original IGA is combined with XFEM-like enrichments which are continuous functions themselves but with discontinuous derivatives. Consequently, the resulting solution space can approximate solutions with weak discontinuities. The method is also applied to curved material interfaces, where the inverse mapping and the curved triangular elements are considered. Third, we develop an IGA collocation method using superconvergent points. The collocation methods are efficient because no numerical integration is needed. In particular when higher polynomial basis applied, the method has a lower computational cost than Galerkin methods. However, the positions of the collocation points are crucial for the accuracy of the method, as they affect the convergent rate significantly. The proposed IGA collocation method uses superconvergent points instead of the traditional Greville abscissae points. The numerical results show the proposed method can have better accuracy and optimal convergence rates, while the traditional IGA collocation has optimal convergence only for even polynomial degrees. Lastly, we propose a novel dynamic multilevel technique for handling image registration. It is application of the B-spline functions in image processing. The procedure considered aims to align a target image from a reference image by a spatial transformation. The method starts with an energy function which is the same as a FEM-based image registration. However, we simplify the solving procedure, working on the energy function directly. We dynamically solve for control points which are coefficients of B-spline basis functions. The new approach is more simple and fast. Moreover, it is also enhanced by a multilevel technique in order to prevent instabilities. The numerical testing consists of two artificial images, four real bio-medical MRI brain and CT heart images, and they show our registration method is accurate, fast and efficient, especially for large deformation problems.}, subject = {Finite-Elemente-Methode}, language = {en} } @article{MortazaviCunibertiRabczuk, author = {Mortazavi, Bohayra and Cuniberti, G. and Rabczuk, Timon}, title = {Mechanical properties and thermal conductivity of graphitic carbon nitride: A molecular dynamics study}, series = {Computational Materials Science}, journal = {Computational Materials Science}, pages = {285 -- 289}, abstract = {Mechanical properties and thermal conductivity of graphitic carbon nitride: A molecular dynamics study}, subject = {Angewandte Mathematik}, language = {en} } @inproceedings{TreyerKleinKoenigetal., author = {Treyer, Lukas and Klein, Bernhard and K{\"o}nig, Reinhard and Meixner, Christine}, title = {Lightweight urban computation interchange (LUCI) system}, series = {Proceedings}, booktitle = {Proceedings}, publisher = {FOSS4G}, address = {Seoul, South Korea}, doi = {10.25643/bauhaus-universitaet.2598}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20160622-25982}, pages = {12}, abstract = {In this paper we introduce LUCI, a Lightweight Urban Calculation Interchange system, designed to bring the advantages of a calculation and content co-ordination system to small planning and design groups by the means of an open source middle-ware. The middle-ware focuses on problems typical to urban planning and therefore features a geo-data repository as well as a job runtime administration, to coordinate simulation models and its multiple views. The described system architecture is accompanied by two exemplary use cases that have been used to test and further develop our concepts and implementations.}, language = {en} } @inproceedings{TreyerKleinKoenigetal., author = {Treyer, Lukas and Klein, Bernhard and K{\"o}nig, Reinhard and Meixner, Christine}, title = {Lightweight urban computation interchange (LUCI) system}, series = {FOSS4G 2015 Conference}, booktitle = {FOSS4G 2015 Conference}, publisher = {FOSS4G}, address = {Seoul, South Korea}, doi = {10.25643/bauhaus-universitaet.2504}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20160118-25042}, pages = {12}, abstract = {In this paper we introduce LUCI, a Lightweight Urban Calculation Interchange system, designed to bring the advantages of a calculation and content co-ordination system to small planning and design groups by the means of an open source middle-ware. The middle-ware focuses on problems typical to urban planning and therefore features a geo-data repository as well as a job runtime administration, to coordinate simulation models and its multiple views. The described system architecture is accompanied by two exemplary use cases that have been used to test and further develop our concepts and implementations.}, subject = {Architektur}, language = {en} } @phdthesis{RodriguezSchaeffer, author = {Rodr{\´i}guez Schaeffer, Alan Paul}, title = {Lighting in urban heritage: case study of Chiapa de Corzo, Chiapas, Mexico}, doi = {10.25643/bauhaus-universitaet.2421}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20150630-24217}, school = {Bauhaus-Universit{\"a}t Weimar}, pages = {327}, abstract = {As human thought was developing, likewise, the technology used for illumination was growing. But a haul through history, reviewing its pages and analyzing it, inherently brings up old and new question, like: Is it possible to alter negatively the image of historic buildings and monuments through inadequate lighting to the degree of distorting the perception that people have of the work? and if so, what are the causes that generate it? Do the light designers take into consideration criteria to protect not only historic buildings and monuments, but also the environment? What are the consequences that may generate the inadequate lighting of urban heritage to the environment? What are the factors to consider for a proper illumination of urban heritage? The answers to these questions will help lay the foundation for proper illumination of the urban heritage, avoiding at the maximum the light pollution and the effects that it generates, seeking a balance and harmonious reconciliation between the technology, urban heritage and environment, taking as a framework and the case study the urban heritage of a city from the colonial era in southern Mexico, with pre-Hispanic roots and where today you can still see through its streets and buildings an atmosphere of mysticism reflection of their folklore and traditions, this city is known as Chiapa de Corzo, Chiapas.}, subject = {Konservierung}, language = {en} } @inproceedings{Neri, author = {Neri, Maria Luisa}, title = {Landscape and City during Fascism: Enrico del Debbio's Foro Mussolini}, series = {Urban design and dictatorship in the 20th century: Italy, Portugal, the Soviet Union, Spain and Germany. History and Historiography}, booktitle = {Urban design and dictatorship in the 20th century: Italy, Portugal, the Soviet Union, Spain and Germany. History and Historiography}, doi = {10.25643/bauhaus-universitaet.2387}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20150504-23877}, pages = {1 -- 16}, abstract = {Beitr{\"a}ge zum Symposium „Urban design and dictatorship in the 20th century: Italy, Portugal, the Soviet Union, Spain and Germany. History and Historiography". Weimar, 21.-22. November 2013}, subject = {St{\"a}dtebau}, language = {en} }