@phdthesis{LopezZermeno, author = {L{\´o}pez Zerme{\~n}o, Jorge Alberto}, title = {Isogeometric and CAD-based methods for shape and topology optimization: Sensitivity analysis, B{\´e}zier elements and phase-field approaches}, doi = {10.25643/bauhaus-universitaet.4710}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20220831-47102}, school = {Bauhaus-Universit{\"a}t Weimar}, abstract = {The Finite Element Method (FEM) is widely used in engineering for solving Partial Differential Equations (PDEs) over complex geometries. To this end, it is required to provide the FEM software with a geometric model that is typically constructed in a Computer-Aided Design (CAD) software. However, FEM and CAD use different approaches for the mathematical description of the geometry. Thus, it is required to generate a mesh, which is suitable for FEM, based on the CAD model. Nonetheless, this procedure is not a trivial task and it can be time consuming. This issue becomes more significant for solving shape and topology optimization problems, which consist in evolving the geometry iteratively. Therefore, the computational cost associated to the mesh generation process is increased exponentially for this type of applications. The main goal of this work is to investigate the integration of CAD and CAE in shape and topology optimization. To this end, numerical tools that close the gap between design and analysis are presented. The specific objectives of this work are listed below: • Automatize the sensitivity analysis in an isogeometric framework for applications in shape optimization. Applications for linear elasticity are considered. • A methodology is developed for providing a direct link between the CAD model and the analysis mesh. In consequence, the sensitivity analysis can be performed in terms of the design variables located in the design model. • The last objective is to develop an isogeometric method for shape and topological optimization. This method should take advantage of using Non-Uniform Rational B-Splines (NURBS) with higher continuity as basis functions. Isogeometric Analysis (IGA) is a framework designed to integrate the design and analysis in engineering problems. The fundamental idea of IGA is to use the same basis functions for modeling the geometry, usually NURBS, for the approximation of the solution fields. The advantage of integrating design and analysis is two-fold. First, the analysis stage is more accurate since the system of PDEs is not solved using an approximated geometry, but the exact CAD model. Moreover, providing a direct link between the design and analysis discretizations makes possible the implementation of efficient sensitivity analysis methods. Second, the computational time is significantly reduced because the mesh generation process can be avoided. Sensitivity analysis is essential for solving optimization problems when gradient-based optimization algorithms are employed. Automatic differentiation can compute exact gradients, automatically by tracking the algebraic operations performed on the design variables. For the automation of the sensitivity analysis, an isogeometric framework is used. Here, the analysis mesh is obtained after carrying out successive refinements, while retaining the coarse geometry for the domain design. An automatic differentiation (AD) toolbox is used to perform the sensitivity analysis. The AD toolbox takes the code for computing the objective and constraint functions as input. Then, using a source code transformation approach, it outputs a code for computing the objective and constraint functions, and their sensitivities as well. The sensitivities obtained from the sensitivity propagation method are compared with analytical sensitivities, which are computed using a full isogeometric approach. The computational efficiency of AD is comparable to that of analytical sensitivities. However, the memory requirements are larger for AD. Therefore, AD is preferable if the memory requirements are satisfied. Automatic sensitivity analysis demonstrates its practicality since it simplifies the work of engineers and designers. Complex geometries with sharp edges and/or holes cannot easily be described with NURBS. One solution is the use of unstructured meshes. Simplex-elements (triangles and tetrahedra for two and three dimensions respectively) are particularly useful since they can automatically parameterize a wide variety of domains. In this regard, unstructured B{\´e}zier elements, commonly used in CAD, can be employed for the exact modelling of CAD boundary representations. In two dimensions, the domain enclosed by NURBS curves is parameterized with B{\´e}zier triangles. To describe exactly the boundary of a two-dimensional CAD model, the continuity of a NURBS boundary representation is reduced to C^0. Then, the control points are used to generate a triangulation such that the boundary of the domain is identical to the initial CAD boundary representation. Thus, a direct link between the design and analysis discretizations is provided and the sensitivities can be propagated to the design domain. In three dimensions, the initial CAD boundary representation is given as a collection of NURBS surfaces that enclose a volume. Using a mesh generator (Gmsh), a tetrahedral mesh is obtained. The original surface is reconstructed by modifying the location of the control points of the tetrahedral mesh using B{\´e}zier tetrahedral elements and a point inversion algorithm. This method offers the possibility of computing the sensitivity analysis using the analysis mesh. Then, the sensitivities can be propagated into the design discretization. To reuse the mesh originally generated, a moving B{\´e}zier tetrahedral mesh approach was implemented. A gradient-based optimization algorithm is employed together with a sensitivity propagation procedure for the shape optimization cases. The proposed shape optimization approaches are used to solve some standard benchmark problems in structural mechanics. The results obtained show that the proposed approach can compute accurate gradients and evolve the geometry towards optimal solutions. In three dimensions, the moving mesh approach results in faster convergence in terms of computational time and avoids remeshing at each optimization step. For considering topological changes in a CAD-based framework, an isogeometric phase-field based shape and topology optimization is developed. In this case, the diffuse interface of a phase-field variable over a design domain implicitly describes the boundaries of the geometry. The design variables are the local values of the phase-field variable. The descent direction to minimize the objective function is found by using the sensitivities of the objective function with respect to the design variables. The evolution of the phase-field is determined by solving the time dependent Allen-Cahn equation. Especially for topology optimization problems that require C^1 continuity, such as for flexoelectric structures, the isogeometric phase field method is of great advantage. NURBS can achieve the desired continuity more efficiently than the traditional employed functions. The robustness of the method is demonstrated when applied to different geometries, boundary conditions, and material configurations. The applications illustrate that compared to piezoelectricity, the electrical performance of flexoelectric microbeams is larger under bending. In contrast, the electrical power for a structure under compression becomes larger with piezoelectricity.}, subject = {CAD}, language = {en} } @phdthesis{Schollmeyer, author = {Schollmeyer, Andre}, title = {Efficient and High-Quality Rendering of Higher-Order Geometric Data Representations}, doi = {10.25643/bauhaus-universitaet.3823}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20181120-38234}, school = {Bauhaus-Universit{\"a}t Weimar}, pages = {143}, abstract = {Computer-Aided Design (CAD) bezeichnet den Entwurf industrieller Produkte mit Hilfe von virtuellen 3D Modellen. Ein CAD-Modell besteht aus parametrischen Kurven und Fl{\"a}chen, in den meisten F{\"a}llen non-uniform rational B-Splines (NURBS). Diese mathematische Beschreibung wird ebenfalls zur Analyse, Optimierung und Pr{\"a}sentation des Modells verwendet. In jeder dieser Entwicklungsphasen wird eine unterschiedliche visuelle Darstellung ben{\"o}tigt, um den entsprechenden Nutzern ein geeignetes Feedback zu geben. Designer bevorzugen beispielsweise illustrative oder realistische Darstellungen, Ingenieure ben{\"o}tigen eine verst{\"a}ndliche Visualisierung der Simulationsergebnisse, w{\"a}hrend eine immersive 3D Darstellung bei einer Benutzbarkeitsanalyse oder der Designauswahl hilfreich sein kann. Die interaktive Darstellung von NURBS-Modellen und -Simulationsdaten ist jedoch aufgrund des hohen Rechenaufwandes und der eingeschr{\"a}nkten Hardwareunterst{\"u}tzung eine große Herausforderung. Diese Arbeit stellt vier neuartige Verfahren vor, welche sich mit der interaktiven Darstellung von NURBS-Modellen und Simulationensdaten befassen. Die vorgestellten Algorithmen nutzen neue F{\"a}higkeiten aktueller Grafikkarten aus, um den Stand der Technik bez{\"u}glich Qualit{\"a}t, Effizienz und Darstellungsgeschwindigkeit zu verbessern. Zwei dieser Verfahren befassen sich mit der direkten Darstellung der parametrischen Beschreibung ohne Approximationen oder zeitaufw{\"a}ndige Vorberechnungen. Die dabei vorgestellten Datenstrukturen und Algorithmen erm{\"o}glichen die effiziente Unterteilung, Klassifizierung, Tessellierung und Darstellung getrimmter NURBS-Fl{\"a}chen und einen interaktiven Ray-Casting-Algorithmus f{\"u}r die Isofl{\"a}chenvisualisierung von NURBSbasierten isogeometrischen Analysen. Die weiteren zwei Verfahren beschreiben zum einen das vielseitige Konzept der programmierbaren Transparenz f{\"u}r illustrative und verst{\"a}ndliche Visualisierungen tiefenkomplexer CAD-Modelle und zum anderen eine neue hybride Methode zur Reprojektion halbtransparenter und undurchsichtiger Bildinformation f{\"u}r die Beschleunigung der Erzeugung von stereoskopischen Bildpaaren. Die beiden letztgenannten Ans{\"a}tze basieren auf rasterisierter Geometrie und sind somit ebenfalls f{\"u}r normale Dreiecksmodelle anwendbar, wodurch die Arbeiten auch einen wichtigen Beitrag in den Bereichen der Computergrafik und der virtuellen Realit{\"a}t darstellen. Die Auswertung der Arbeit wurde mit großen, realen NURBS-Datens{\"a}tzen durchgef{\"u}hrt. Die Resultate zeigen, dass die direkte Darstellung auf Grundlage der parametrischen Beschreibung mit interaktiven Bildwiederholraten und in subpixelgenauer Qualit{\"a}t m{\"o}glich ist. Die Einf{\"u}hrung programmierbarer Transparenz erm{\"o}glicht zudem die Umsetzung kollaborativer 3D Interaktionstechniken f{\"u}r die Exploration der Modelle in virtuellenUmgebungen sowie illustrative und verst{\"a}ndliche Visualisierungen tiefenkomplexer CAD-Modelle. Die Erzeugung stereoskopischer Bildpaare f{\"u}r die interaktive Visualisierung auf 3D Displays konnte beschleunigt werden. Diese messbare Verbesserung wurde zudem im Rahmen einer Nutzerstudie als wahrnehmbar und vorteilhaft befunden.}, subject = {Rendering}, language = {en} } @inproceedings{KoenigSchmitt, author = {K{\"o}nig, Reinhard and Schmitt, Gerhard}, title = {Backcasting and a new way of command in computational design : Proceedings}, series = {CAADence in Architecture Conference}, booktitle = {CAADence in Architecture Conference}, editor = {Szoboszlai, Mih{\´a}ly}, address = {Budapest}, doi = {10.25643/bauhaus-universitaet.2599}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20160622-25996}, pages = {15 -- 25}, abstract = {It's not uncommon that analysis and simulation methods are used mainly to evaluate finished designs and to proof their quality. Whereas the potential of such methods is to lead or control a design process from the beginning on. Therefore, we introduce a design method that move away from a "what-if" forecasting philosophy and increase the focus on backcasting approaches. We use the power of computation by combining sophisticated methods to generate design with analysis methods to close the gap between analysis and synthesis of designs. For the development of a future-oriented computational design support we need to be aware of the human designer's role. A productive combination of the excellence of human cognition with the power of modern computing technology is needed. We call this approach "cognitive design computing". The computational part aim to mimic the way a designer's brain works by combining state-of-the-art optimization and machine learning approaches with available simulation methods. The cognition part respects the complex nature of design problems by the provision of models for human-computation interaction. This means that a design problem is distributed between computer and designer. In the context of the conference slogan "back to command", we ask how we may imagine the command over a cognitive design computing system. We expect that designers will need to let go control of some parts of the design process to machines, but in exchange they will get a new powerful command on complex computing processes. This means that designers have to explore the potentials of their role as commanders of partially automated design processes. In this contribution we describe an approach for the development of a future cognitive design computing system with the focus on urban design issues. The aim of this system is to enable an urban planner to treat a planning problem as a backcasting problem by defining what performance a design solution should achieve and to automatically query or generate a set of best possible solutions. This kind of computational planning process offers proof that the designer meets the original explicitly defined design requirements. A key way in which digital tools can support designers is by generating design proposals. Evolutionary multi-criteria optimization methods allow us to explore a multi-dimensional design space and provide a basis for the designer to evaluate contradicting requirements: a task urban planners are faced with frequently. We also reflect why designers will give more and more control to machines. Therefore, we investigate first approaches learn how designers use computational design support systems in combination with manual design strategies to deal with urban design problems by employing machine learning methods. By observing how designers work, it is possible to derive more complex artificial solution strategies that can help computers make better suggestions in the future.}, subject = {CAD}, language = {en} } @inproceedings{Koenig, author = {K{\"o}nig, Reinhard}, title = {CPlan: An Open Source Library for Computational Analysis and Synthesis}, series = {33rd eCAADe Conference}, booktitle = {33rd eCAADe Conference}, editor = {Martens, Bob and Wurzer, G, Gabriel and Grasl, Tomas and Lorenz, Wolfgang and Schaffranek, Richard}, publisher = {Vienna University of Technology}, address = {Vienna}, doi = {10.25643/bauhaus-universitaet.2503}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20160118-25037}, pages = {245 -- 250}, abstract = {Some caad packages offer additional support for the optimization of spatial configurations, but the possibilities for applying optimization are usually limited either by the complexity of the data model or by the constraints of the underlying caad system. Since we missed a system that allows to experiment with optimization techniques for the synthesis of spatial configurations, we developed a collection of methods over the past years. This collection is now combined in the presented open source library for computational planning synthesis, called CPlan. The aim of the library is to provide an easy to use programming framework with a flat learning curve for people with basic programming knowledge. It offers an extensible structure that allows to add new customized parts for various purposes. In this paper the existing functionality of the CPlan library is described.}, subject = {Architektur}, language = {en} } @article{Koenig2011, author = {K{\"o}nig, Reinhard}, title = {Generierung von Grundriss-Layouts mittels hybrider Evolutions-Strategie}, doi = {10.25643/bauhaus-universitaet.806}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20110414-15425}, year = {2011}, abstract = {Der vorliegende Text beschreibt ein computerbasiertes Verfahren zur L{\"o}sung von Layout-problemen in Architektur und St{\"a}dtebau, welches mit m{\"o}glichst wenig Problemwissen auskommt und schnell brauchbare Ergebnisse liefert, die durch schrittweises Hinzuf{\"u}gen von Problemwissen interaktiv weiter ausgearbeitet werden k{\"o}nnen. F{\"u}r das generative Verfahren wurde eine Evolutions-Strategie verwendet, die mit Mechanismen zur Kollisionserkennung und virtuellen Federn zu einem hybriden Algorithmus kombiniert wurde. Dieser dient erstens der L{\"o}sung des Problems der Dichten Packung von Rechtecken sowie zweitens der Herstellung bestimmter topologischer Beziehungen zwischen diesen Rechtecken. Die Bearbeitung beider Probleme wird durch schrittweise Erweiterung grundlegender Verfahren untersucht, wobei die einzelnen Schritte anhand von Performancetests miteinander verglichen werden. Am Ende wird ein iterativer Algorithmus vorgestellt, der einerseits optimale L{\"o}sungen garantiert und andererseits diese L{\"o}sungen in einer f{\"u}r eine akzeptable Nutzerinteraktion ausreichenden Geschwindigkeit generiert.}, subject = {CAD}, language = {de} } @article{SchneiderBraunesThurowetal.2011, author = {Schneider, Sven and Braunes, J{\"o}rg and Thurow, Torsten and K{\"o}nig, Reinhard and Tonn, Christian}, title = {Entwerfen Versionieren: Probleme und L{\"o}sungsans{\"a}tze f{\"u}r die Organisation verteilter Entwurfsprozesse}, doi = {10.25643/bauhaus-universitaet.807}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20110414-15439}, year = {2011}, abstract = {Entwerfen ist ein komplexer Vorgang. Soll dieser Vorgang nicht allein, sondern r{\"a}umlich verteilt mit mehreren Beteiligten gemeinsam stattfinden, so sind digitale Werkzeuge zur Unterst{\"u}tzung dieses Prozesses unumg{\"a}nglich. Die Verwendung von Werkzeugen f{\"u}r Ent-wurfsprozesse bedeutet jedoch immer auch eine Manipulation des zu unterst{\"u}tzenden Prozesses selbst. Im Falle von Werkzeugen zur Unterst{\"u}tzung der Kollaboration mehrerer Beteiligter stellen die implementierten Koordinationsmechanismen solche prozessbeeinflussenden Faktoren dar. Damit diese Mechanismen, entsprechend der Charakteristika kreativer Prozesse, so flexibel wie m{\"o}glich gestaltet werden k{\"o}nnen, liegt die Anforderung auf technischer Ebene darin, ein geeignetes Konzept f{\"u}r eine nachvollziehbare Speicherung (Versionierung) der stattfindenden Entwurfshandlungen zu schaffen. Der vorliegende Artikel besch{\"a}ftigt sich mit dem Thema der Entwurfsversionierung in computergest{\"u}tzten kollaborativen Arbeitsumgebungen. Vor dem Hintergrund, dass die Versionierung den kreativen Entwurfsprozess m{\"o}glichst wenig manipulieren soll, werden technische sowie konzeptionelle Probleme der diskutiert und L{\"o}sungsans{\"a}tze f{\"u}r diese vorgestellt.}, subject = {CAD}, language = {de} } @article{Koenig2011, author = {K{\"o}nig, Reinhard}, title = {Generating urban structures: A method for urban planning supported by multi-agent systems and cellular automata}, doi = {10.25643/bauhaus-universitaet.1448}, url = {http://nbn-resolving.de/urn:nbn:de:101:1-201105183228}, year = {2011}, abstract = {This work is based on the concept that the structure of a city can be defined by six basic urban patterns. To enable more complex urban planning as a long-term objective I have developed a simulation method for generating these basic patterns and for combining them to form various structures. The generative process starts with the two-dimensional organisation of streets followed by the parceling of the remaining areas. An agent-based diffusion-contact model is the basis of these first two steps. Then, with the help of cellular automata, the sites for building on are defined and a three-dimensional building structure is derived. I illustrate the proposed method by showing how it can be applied to generate possible structures for an urban area in the city of Munich.}, subject = {CAD}, language = {en} } @article{Koenig2010, author = {K{\"o}nig, Reinhard}, title = {Generative Planungsmethoden aus strukturalistischer Perspektive}, doi = {10.25643/bauhaus-universitaet.811}, url = {http://nbn-resolving.de/urn:nbn:de:101:1-201105114205}, year = {2010}, abstract = {N{\"a}hert man sich der Frage nach den Zusammenh{\"a}ngen zwischen Strukturalismus und generativen algorithmischen Planungsmethoden, so ist zun{\"a}chst zu kl{\"a}ren, was man unter Strukturalismus in der Architektur versteht. Allerdings gibt es letztlich keinen verbindlichen terminologischen Rahmen, innerhalb dessen sich eine solche Kl{\"a}rung vollziehen k{\"o}nnte. Strukturalismus in der Architektur wird oftmals auf ein formales Ph{\"a}nomen und damit auf eine Stilfrage reduziert. Der vorliegende Text will sich nicht mit Stilen und Ph{\"a}nomenen strukturalistischer Architektur auseinandersetzen, sondern konzentriert sich auf die Betrachtung strukturalistischer Entwurfsmethoden und stellt Bez{\"u}ge her zu algorithmischen Verfahren, wobei das Zusammenspiel zwischen regelgeleitetem und intuitivem Vorgehen beim Entwerfen herausgearbeitet wird.}, subject = {Strukturalismus}, language = {de} } @article{KoenigThurowBraunesetal.2010, author = {K{\"o}nig, Reinhard and Thurow, Torsten and Braunes, J{\"o}rg and Donath, Dirk and Schneider, Sven}, title = {Technische Einf{\"u}hrung in FREAC: A Framework for Enhancing Research in Architectural Design and Communication}, doi = {10.25643/bauhaus-universitaet.1449}, url = {http://nbn-resolving.de/urn:nbn:de:101:1-201105183216}, year = {2010}, abstract = {Im vorliegenden Beitrag wird ein Framework f{\"u}r ein verteiltes dynamisches Produktmodell (FREAC) vorgestellt, welches der experimentellen Softwareentwicklung dient. Bei der Entwicklung von FREAC wurde versucht, folgende Eigenschaften umzusetzen, die bei herk{\"o}mmlichen Systemen weitgehend fehlen: Erstens eine hohe Flexibilit{\"a}t, also eine m{\"o}glichst hohe Anpassbarkeit f{\"u}r unterschiedliche Fachdisziplinen; Zweitens die M{\"o}glichkeit, verschiedene Tools nahtlos miteinander zu verkn{\"u}pfen; Drittens die verteilte Modellbearbeitung in Echtzeit; Viertens das Abspeichern des gesamten Modell-Bearbeitungsprozesses; F{\"u}nftens eine dynamische Erweiterbarkeit sowohl f{\"u}r Softwareentwickler, als auch f{\"u}r die Nutzer der Tools. Die Bezeichnung FREAC umfasst sowohl das Framework zur Entwicklung und Pflege eines Produktmodells (FREAC-Development) als auch die entwickelten Tools selbst (FREAC-Tools).}, subject = {CAD}, language = {de} } @phdthesis{Spiekermann2008, author = {Spiekermann, Christoph}, title = {Unterst{\"u}tzung der Material- und Produktauswahl in der Architektur durch Plausibilit{\"a}t der Entscheidung}, doi = {10.25643/bauhaus-universitaet.1350}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20080925-14253}, school = {Bauhaus-Universit{\"a}t Weimar}, year = {2008}, abstract = {Architektur wird vorwiegend {\"u}ber die den Raum begrenzenden Oberfl{\"a}chen wahrgenommen. Das Oberfl{\"a}chenmaterial kann daher mit seinen sinnlichen Eigenschaften die Entwurfsintention unterst{\"u}tzen, zugleich muss es aber auch zahlreiche technische, {\"o}konomische und {\"o}kologische Anforderungen erf{\"u}llen. Materialwahl in der Architektur bedeutet somit das Abw{\"a}gen einer Vielzahl von Parametern, die sich sowohl inhaltlich als auch hinsichtlich ihrer Relevanz stark unterscheiden. Die Entscheidung f{\"u}r ein Material kann dabei durch verschiedene analoge und digitale Ans{\"a}tze unterst{\"u}tzt werden. Die vorhandenen Systeme sind jedoch allesamt begrenzt: in den von ihnen ber{\"u}cksichtigten Aspekten, den m{\"o}glichen Suchwegen oder ihren Inhalten. Keines der in dieser Arbeit untersuchten Systeme ber{\"u}cksichtigt zudem die unterschiedliche Wichtigkeit oder gegenseitige Abh{\"a}ngigkeiten und Unsch{\"a}rfen der in die Materialwahl einfließenden Kriterien. Die vorliegende Arbeit formuliert daher eine Gesamtstrategie zur besseren Unterst{\"u}tzung der Entscheidung f{\"u}r ein Oberfl{\"a}chenmaterial. Im Wesentlichen wird dabei eine Methode vorgestellt, wie die inhaltlich h{\"o}chst unterschiedlichen Kriterien, welche Einfluss auf die Materialwahl aus{\"u}ben, mit ihrer jeweiligen Relevanz gegeneinander in Ansatz gebracht werden k{\"o}nnen, um eine umfassende Bewertung der Materialalternativen zu erm{\"o}glichen. In einem zweiten Schritt wird mit Multidimensional Scaling eine Technik der Informationsvisualisierung benutzt, die eine zus{\"a}tzliche Unterst{\"u}tzung durch weitere Analysem{\"o}glichkeiten und andere Suchwege er{\"o}ffnet. Das vorgeschlagene Verfahren ist in einem Software-Prototyp umgesetzt. Die Arbeit leistet damit einen Beitrag, die Auswahl eines geeigneten Materials in der Architektur zu erleichtern, diese Entscheidung plausibel begr{\"u}nden zu k{\"o}nnen und den Weg der Entscheidungsfindung nachvollziehbar werden zu lassen.}, subject = {Entscheidungsbegr{\"u}ndung}, language = {de} } @article{Koenig, author = {K{\"o}nig, Reinhard}, title = {Computers in the design phase - Ten thesis on their uselessness}, series = {Der Generalist}, journal = {Der Generalist}, doi = {10.25643/bauhaus-universitaet.2607}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20160622-26075}, abstract = {At the end of the 1960s, architects at various universities world- wide began to explore the potential of computer technology for their profession. With the decline in prices for PCs in the 1990s and the development of various computer-aided architectural design systems (CAAD), the use of such systems in architectural and planning offices grew continuously. Because today no ar- chitectural office manages without a costly CAAD system and because intensive soſtware training has become an integral part of a university education, the question arises about what influence the various computer systems have had on the design process forming the core of architectural practice. The text at hand devel- ops ten theses about why there has been no success to this day in introducing computers such that new qualitative possibilities for design result. RESTRICTEDNESS}, subject = {CAD}, language = {en} } @article{Koenig, author = {K{\"o}nig, Reinhard}, title = {Die Stadt der Agenten und Automaten}, series = {FORUM - Architektur \& Bauforum}, journal = {FORUM - Architektur \& Bauforum}, doi = {10.25643/bauhaus-universitaet.2608}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20160622-26083}, abstract = {PLANUNGSUNTERST{\"U}TZUNG DURCH DIE ANALYSE R{\"A}UMLICHER PROZESSE MITTELS COMPUTERSIMULATIONEN. Erst wenn man - zumindest im Prinzip - versteht, wie eine Stadt mit ihren komplexen, verwobenen Vorg{\"a}ngen im Wesentlichen funktioniert, ist eine sinnvolle Stadtplanung m{\"o}glich. Denn jede Planung bedeutet einen Eingriff in den komplexen Organismus einer Stadt. Findet dieser Eingriff ohne Wissen {\"u}ber die Funktionsweise des Organismus statt, k{\"o}nnen auch die Auswirkungen nicht abgesch{\"a}tzt werden. Dieser Beitrag stellt dar, wie urbane Prozesse mittels Computersimulationen unter Zuhilfenahme so genannter Multi-Agenten-Systeme und Zellul{\"a}rer Automaten verstanden werden k{\"o}nnen. von}, subject = {CAD}, language = {de} } @inproceedings{BaitschHartmann, author = {Baitsch, Matthias and Hartmann, Dietrich}, title = {A FRAMEWORK FOR THE INTERACTIVE VISUALIZATION OF ENGINEERING MODELS}, editor = {G{\"u}rlebeck, Klaus and K{\"o}nke, Carsten}, organization = {Bauhaus-Universit{\"a}t Weimar}, doi = {10.25643/bauhaus-universitaet.2919}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20170327-29194}, pages = {9}, abstract = {Interactive visualization based on 3D computer graphics nowadays is an indispensable part of any simulation software used in engineering. Nevertheless, the implementation of such visualization software components is often avoided in research projects because it is a challenging and potentially time consuming task. In this contribution, a novel Java framework for the interactive visualization of engineering models is introduced. It supports the task of implementing engineering visualization software by providing adequate program logic as well as high level classes for the visual representation of entities typical for engineering models. The presented framework is built on top of the open source visualization toolkit VTK. In VTK, a visualization model is established by connecting several filter objects in a so called visualization pipeline. Although designing and implementing a good pipeline layout is demanding, VTK does not support the reuse of pipeline layouts directly. Our framework tailors VTK to engineering applications on two levels. On the first level it adds new - engineering model specific - filter classes to VTK. On the second level, ready made pipeline layouts for certain aspects of engineering models are provided. For instance there is a pipeline class for one-dimensional elements like trusses and beams that is capable of showing the elements along with deformations and member forces. In order to facilitate the implementation of a graphical user interface (GUI) for each pipeline class, there exists a reusable Java Swing GUI component that allows the user to configure the appearance of the visualization model. Because of the flexible structure, the framework can be easily adapted and extended to new problem domains. Currently it is used in (i) an object-oriented p-version finite element code for design optimization, (ii) an agent based monitoring system for dam structures and (iii) the simulation of destruction processes by controlled explosives based on multibody dynamics. Application examples from all three domains illustrates that the approach presented is powerful as well as versatile.}, subject = {Architektur }, language = {en} } @inproceedings{Eickelkamp, author = {Eickelkamp, Jens Peter}, title = {LIQUIDIT{\"A}TSPLANUNG VON BAUPROJEKTEN}, editor = {G{\"u}rlebeck, Klaus and K{\"o}nke, Carsten}, organization = {Bauhaus-Universit{\"a}t Weimar}, doi = {10.25643/bauhaus-universitaet.2948}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20170327-29483}, pages = {12}, abstract = {Die Liquidit{\"a}tsplanung von Bauunternehmen XE "Liquidit{\"a}tsplanung" gilt als ein wesentliches Steuerungs-, Kontroll- sowie Informationsinstrument f{\"u}r interne und externe Adressaten und {\"u}bt eine Entscheidungsunterst{\"u}tzungsfunktion aus. Da die einzelnen Bauprojekte einen wesentlichen Anteil an den Gesamtkosten des Unternehmens ausmachen, besitzen diese auch einen erheblichen Einfluß auf die Liquidit{\"a}t und die Zahlungsf{\"a}higkeit der Bauunternehmung. Dem folgend ist es in der Baupraxis eine {\"u}bliche Verfahrensweise, die Liquidit{\"a}tsplanung zuerst projektbezogen zu erstellen und anschließend auf Unternehmensebene zu verdichten. Ziel der Ausf{\"u}hrungen ist es, die Zusammenh{\"a}nge von Arbeitskalkulation XE "Arbeitskalkulation" , Ergebnisrechnung XE "Ergebnisrechnung" und Finanzrechnung XE "Finanzrechnung" in Form eines deterministischen XE "Erkl{\"a}rungsmodells" Planungsmodells auf Projektebene darzustellen. Hierbei soll das Verst{\"a}ndnis und die Bedeutung der Verkn{\"u}pfungen zwischen dem technisch-orientierten Bauablauf und dessen Darstellung im Rechnungs- und Finanzwesen herausgestellt werden. Die Vorg{\"a}nge aus der Bauabwicklung, das heißt die Abarbeitung der Bauleistungsverzeichnispositionen und deren zeitliche Darstellung in einem Bauzeitenplan sind periodisiert in Gr{\"o}ßen der Betriebsbuchhaltung (Leistung, Kosten) zu transformieren und anschließend in der Finanzrechnung (Einzahlungen., Auszahlungen) nach Kreditoren und Debitoren aufzuschl{\"u}sseln.}, subject = {Architektur }, language = {de} } @inproceedings{StoimenovaLinsDatchevaetal., author = {Stoimenova, Eugenia and Lins, Yvonne and Datcheva, Maria and Schanz, Tom}, title = {INVERSE MODELLING OF SOIL HYDRAULIC CHARACTERISTIC FUNCTIONS}, editor = {G{\"u}rlebeck, Klaus and K{\"o}nke, Carsten}, organization = {Bauhaus-Universit{\"a}t Weimar}, doi = {10.25643/bauhaus-universitaet.2985}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20170327-29858}, pages = {12}, abstract = {In this paper we evaluate 2D models for soil-water characteristic curve (SWCC), that incorporate the hysteretic nature of the relationship between volumetric water content θ and suction ψ. The models are based on nonlinear least squares estimation of the experimental data for sand. To estimate the dependent variable θ the proposed models include two independent variables, suction and sensors reading position (depth d in the column test). The variable d represents not only the position where suction and water content are measured but also the initial suction distribution before each of the hydraulic loading test phases. Due to this the proposed 2D regression models acquire the advantage that they: (a) can be applied for prediction of θ for any position along the column and (b) give the functional form for the scanning curves.}, subject = {Architektur }, language = {en} } @inproceedings{SchapkeSchererKatranuschkov, author = {Schapke, Sven-Eric and Scherer, Raimar J. and Katranuschkov, Peter}, title = {SEMANTIC SERVICE ENVIRONMENTS FOR INTEGRATING TEXT WITH MODEL-BASED INFORMATION IN AEC/FM}, editor = {G{\"u}rlebeck, Klaus and K{\"o}nke, Carsten}, organization = {Bauhaus-Universit{\"a}t Weimar}, doi = {10.25643/bauhaus-universitaet.3012}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20170327-30125}, pages = {10}, abstract = {In distributed project organisations and collaboration there is a need for integrating unstructured self-contained text information with structured project data. We consider this a process of text integration in which various text technologies can be used to externalise text content and consolidate it into structured information or flexibly interlink it with corresponding information bases. However, the effectiveness of text technologies and the potentials of text integration greatly vary with the type of documents, the project setup and the available background knowledge. The goal of our research is to establish text technologies within collaboration environments to allow for (a) flexibly combining appropriate text and data management technologies, (b) utilising available context information and (c) the sharing of text information in accordance to the most critical integration tasks. A particular focus is on Semantic Service Environments that leverage on Web service and Semantic Web technologies and adequately support the required systems integration and parallel processing of semi-structured and structured information. The paper presents an architecture for text integration that extends Semantic Service Environments with two types of integration services. Backbone to the Information Resource Sharing and Integration Service is a shared environment ontology that consolidates information on the project context and the available model, text and general linguistic resources. It also allows for the configuration of Semantic Text Analysis and Annotation Services to analyse the text documents as well as for capturing the discovered text information and sharing it through semantic notification and retrieval engines. A particular focus of the paper is the definition of the overall integration process configuring a complementary set of analyses and information sharing components.}, subject = {Architektur }, language = {en} } @inproceedings{TrummerDenzlerSuesse, author = {Trummer, Michael and Denzler, J. and S{\"u}ße, Herbert}, title = {PRECISE 3D MEASUREMENT WITH STANDARD MEANS AND MINIMIAL USER INTERACTION - EXTENDED SINGLE-VIEW RECONSTRUCTION}, editor = {G{\"u}rlebeck, Klaus and K{\"o}nke, Carsten}, organization = {Bauhaus-Universit{\"a}t Weimar}, doi = {10.25643/bauhaus-universitaet.3028}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20170327-30282}, pages = {8}, abstract = {The paper proposes a new method for general 3D measurement and 3D point reconstruction. Looking at its features, the method explicitly aims at practical applications. These features especially cover low technical expenses and minimal user interaction, a clear problem separation into steps that are solved by simple mathematical methods (direct, stable and optimal with respect to least error squares), and scalability. The method expects the internal and radial distortion parameters of the used camera(s) as inputs, and a plane quadrangle with known geometry within the scene. At first, for each single picture the 3D position of the reference quadrangle (with respect to each camera coordinate frame) is calculated. These 3D reconstructions of the reference quadrangle are then used to yield the relative external parameters of each camera regarding the first one. With known external parameters, triangulation is finally possible. The differences from other known procedures are outlined, paying attention to the stable mathematical methods (no usage of nonlinear optimization) and the low user interaction with good results at the same time.}, subject = {Architektur }, language = {en} } @inproceedings{MisyuraVolkova, author = {Misyura, E. and Volkova, Viktorija}, title = {APPLICATION OF THE MATHEMATICAL METHODS TO INVESTIGATION OF DYNAMICAL PROPERTIES OF A CABLE}, editor = {G{\"u}rlebeck, Klaus and K{\"o}nke, Carsten}, organization = {Bauhaus-Universit{\"a}t Weimar}, doi = {10.25643/bauhaus-universitaet.3031}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20170327-30313}, pages = {7}, abstract = {The paper is devoted to the investigation of dynamical behavior of a cable under influence of various types of excitations. Such element has a low rigidity and is sensitive to dynamic effect. The structural scheme is a cable which ends are located at different level. The analysis of dynamical behavior of the cable under effect of kinematical excitation which is represented by the oscillations of the upper part of tower is given. The scheme of cable is accepted such, that lower end of an inclined cable is motionless. The motion of the upper end is assumed only in horizontal direction. The fourth-order Runge-Kutta method was realized in software. The fast Fourier transform was used for spectral analysis. Standard graphical software was adopted for presenting results of investigations. The mathematical model of oscillations of a cable was developed by the account of the viscous damping. The analysis of dynamical characteristics of a cable for various parameters of damping and kinematical excitation was carried out. The time series, spectral characteristics and amplitude-frequencies characteristics was obtained. The resonance amplitude for different oscillating regimes was estimated. It is noted that increasing of the coefficient of the viscous damping and decreasing of the amplitude of tower's oscillations reduces the value of the critical frequency and the resonant amplitudes.}, subject = {Architektur }, language = {en} } @inproceedings{KimuraMakinoMaegaitoetal., author = {Kimura, Atsushi and Makino, Y. and Maegaito, Kentaro and Suzuki, Osamu}, title = {ITERATION DYNAMICAL SYSTEMS OF DISCRETE LAPLACIANS ON THE PLANE LATTICE (II) (THE VISUAL IMPRESSIONS GIVEN BY DESIGN-PATTERNS)}, editor = {G{\"u}rlebeck, Klaus and K{\"o}nke, Carsten}, organization = {Bauhaus-Universit{\"a}t Weimar}, doi = {10.25643/bauhaus-universitaet.2973}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20170327-29731}, pages = {4}, abstract = {The present study was designed to investigate the underlying factors determining the visual impressions of design-patterns that have complex textures. Design-patterns produced by "the dynamical system defined by iterations of discrete Laplacians on the plane lattice" were adopted as stimuli because they were not only complex, but also defined mathematically. In the experiment, 21 graduate and undergraduate students sorted 102 design-patterns into several groups by visual impressions. Those 102 patterns were classified into 12 categories by the cluster analysis. The results showed that the regularity of pattern was a most efficient factor for determining visual impressions of design-pattern, and there were some correspondence between visual impressions and mathematical variables of design-pattern. Especially, the visual impressions were influenced greatly by the neighborhood, and less influenced by steps of iterations.}, subject = {Architektur }, language = {en} } @inproceedings{Faustino, author = {Faustino, Nelson}, title = {FISCHER DECOMPOSITION FOR DIFFERENCE DIRAC OPERATORS}, editor = {G{\"u}rlebeck, Klaus and K{\"o}nke, Carsten}, organization = {Bauhaus-Universit{\"a}t Weimar}, doi = {10.25643/bauhaus-universitaet.2955}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20170327-29551}, pages = {10}, abstract = {We establish the basis of a discrete function theory starting with a Fischer decomposition for difference Dirac operators. Discrete versions of homogeneous polynomials, Euler and Gamma operators are obtained. As a consequence we obtain a Fischer decomposition for the discrete Laplacian. For the sake of simplicity we consider in the first part only Dirac operators which contain only forward or backward finite differences. Of course, these Dirac operators do not factorize the classic discrete Laplacian. Therefore, we will consider a different definition of a difference Dirac operator in the quaternionic case which do factorizes the discrete Laplacian.}, subject = {Architektur }, language = {en} }