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Mikroelektronik und Mikrosystemtechnik in Kombination mit Informations- und Kommunikations-technik erlauben es mittlerweile, Rechenleistung und Kommunikationsfähigkeit in kleinsten Formaten, mit geringsten Energien und zu günstigen Preisen nutzbringend in unser privates und berufliches Umfeld einzubringen. Beispiele sind Notebook-PC, PDA, Handy und das Navigationßystem im Auto. Aber auch eingebettete Elektronik in Komponenten, Geräten und Systemen ist nunmehr zur Selbstverständlichkeit geworden. Bekannte Beispiele aus der Haustechnik sind Mikroprozeßoren in Heizungs- und Alarmanlagen und aber auch in Komponenten wie Brand- und Bewegungsmelder. Wir nähern uns dem vor einigen Jahren noch als Vision bezeichneten Zustand der überall vorhandenen elektronischen Rechenleistung (engl. ubiquitous computing) bzw. des von Informationsverarbeitung durchdrungenen täglichen Umfelds (engl. pervasive computing). Werden die TGA-Komponenten genau wie die größeren Computerkomponenten (z.B. PCs, Server) über Datenschnittstellen zu räumlich verteilten Netzwerken verknüpft (z.B. Internet, Intranet) und mit einer systemübergreifenden und adäquaten Intelligenz (Software) programmiert, so können neuartige Funktionalitäten im jeweiligen Anwendungsumfeld (engl. ambient intelligence, kurz AmI, [1]) entstehen. Hier liegt bei Gebäuden und Räumen speziell eine große Chance, die bislang einer ganzheitlichen Systemkonzeption unter Einschluß von Architektur, Gebäudephysik, technischer Gebäudeausrüstung (TGA) und Gebäudeautomation (GA) im Wege stehende Gewerketrennung zu überwinden. Es entstehen für div. Anwendungszwecke systemisch integrierte >smart areas< (nach Prof. Becker, FH Biberach). Im vorliegenden Beitrag erläuterte Beispiele für AmI-Lösungen im Immobilienbereich sind Raumsysteme zur automatischen und sicheren Erkennung von Notfällen, z.B. in Pflegeheimen; sich automatisch an die Nutzung und den Nutzer bzgl. Klima und Beleuchtung adaptierende Raumsysteme im Büro- oder Hotelbereich und die elektronische Aßistenz des Bau- und Betriebsprozeßes von Gebäuden. Im Duisburger inHaus-Innovationszentrum für Intelligente Raum- und Gebäudesysteme der Fraunhofer-Gesellschaft wurden in den letzten Jahren erste Lösungen mit diesem neuartigen Ansatz konzipiert, entwickelt und erprobt. Der Beitrag beschreibt nach einer kurzen Skizzierung des Ambient-Intelligence-Ansatzes an Beispielen Möglichkeiten für den Transfer dieser neuen Technologie in den Raum- und Gebäudebereich. Es folgt eine abschließende Zusammenfaßung und eine Einschätzung der Zukunftspotenziale der Ambient Intelligence in Raum und Bau.
The modeling of crack propagation in plain and reinforced concrete structures is still a field for many researchers. If a macroscopic description of the cohesive cracking process of concrete is applied, generally the Fictitious Crack Model is utilized, where a force transmission over micro cracks is assumed. In the most applications of this concept the cohesive model represents the relation between the normal crack opening and the normal stress, which is mostly defined as an exponential softening function, independently from the shear stresses in tangential direction. The cohesive forces are then calculated only from the normal stresses. By Carol et al. 1997 an improved model was developed using a coupled relation between the normal and shear damage based on an elasto-plastic constitutive formulation. This model is based on a hyperbolic yield surface depending on the normal and the shear stresses and on the tensile and shear strength. This model also represents the effect of shear traction induced crack opening. Due to the elasto-plastic formulation, where the inelastic crack opening is represented by plastic strains, this model is limited for applications with monotonic loading. In order to enable the application for cases with un- and reloading the existing model is extended in this study using a combined plastic-damage formulation, which enables the modeling of crack opening and crack closure. Furthermore the corresponding algorithmic implementation using a return mapping approach is presented and the model is verified by means of several numerical examples. Finally an investigation concerning the identification of the model parameters by means of neural networks is presented. In this analysis an inverse approximation of the model parameters is performed by using a given set of points of the load displacement curves as input values and the model parameters as output terms. It will be shown, that the elasto-plastic model parameters could be identified well with this approach, but require a huge number of simulations.
Analysis of the reinforced concrete chimney geometry changes and their influence on the stresses in the chimney mantle was made. All the changes were introduced to a model chimney and compared. Relations between the stresses in the mantle of the chimney and the deformations determined by the change of the chimney's vertical axis geometry were investigated. The vertical axis of chimney was described by linear function (corresponding to the real rotation of the chimney together with the foundation), and by parabolic function (corresponding to the real dislocation of the chimney under the influence of the horizontal forces - wind). The positive stress pattern in the concrete as well as the negative stress pattern in the reinforcing steel have been presented. The two cases were compared. Analysis of the stress changes in the chimney mantle depending on the modification in the thickness of the mantle (the thickness of the chimney mantle was altered in the linear or the abrupt way) was carried out. The relation between the stresses and the chimney's diameter change from the bottom to the top of the chimney was investigated. All the analyses were conducted by means of a specially developed computer program created in Mathematica environment. The program makes it also possible to control calculations and to visualize the results of the calculations at every stage of the calculation process.
This paper presents two new methods for analysis of a technical state of large-panel residential buildings. The first method is based on elements extracted from the classical methods and on data about repairs and modernization collected from building documentations. The technical state of a building is calculated as a sum of several groups of elements defining the technical state. The deterioration in this method depends on: - time, which has passed since last repair of element or time which has passed since construction, - estimate of the state of element groups which can be determined on basis of yearly controls. This is a new unique method. it is easy to use, does not need expertise. The required data could be extracted easily from building documentations. For better accuracy the data from building inspections should be applied (in Poland inspections are made every year). The second method is based on the extracted data processing by means of the artificial neural networks. The aim is to learn the artificial neural network configurations for a set of data containing values of the technical state and information about building repairs for last years (or other information and building parameters) and next to analyse new buildings by the instructed neural network. The second profit from using artificial neural networks is the reduction of number of parameters. Instead of more then 40 parameters describing building, about 6-12 are usually sufficient for satisfactory accuracy. This method could have lower accuracy but it is less prone to data errors.
Procedures of a construction of general solutions for some classes of partial differential equations (PDEs) are proposed and a symmetry operators approach to the raising the orders of the polynomial solutions to linear PDEs are develops. We touch upon an ''operator analytic function theory'' as the solution of a frequent classes of the equations of mathematical physics, when its symmetry operators forms vast enough space. The MAPLE© package programs for the building the operator variables is elaborated also.
Für die Ausführung des Oberbaus von Verkehrsflächen existiert in Abhängigkeit von projektspezifischen Voraussetzungen eine Vielzahl von verschiedenen Varianten. Aufgrund von Erfahrungen der Projektplaner werden bei ähnlichen Voraussetzungen häufig gleichartige Ausführungsvarianten gewählt. Um eine mögliche Lösungsvariante für den Straßenoberbau zu erhalten, sollten daher nicht nur die gesetzlichen Richtlinien sondern auch bereits beendete Projekte berücksichtigt werden. Im Rahmen eines Wissenschaftlichen Kollegs an der Bauhaus-Universität Weimar wurde die Anwendung des Case-Based Reasoning für die Auswahl von Ausführungsvarianten für den Straßenoberbau untersucht. In diesem Beitrag werden die grundlegenden Konzepte des Case-Based Reasoning und die Bestimmung von ähnlichen Varianten anhand einfacher Beispiele aus dem Straßenoberbau dargestellt.
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.
The quaternionic operator calculus can be applied very elegantly to solve many important boundary value problems arising in fluid dynamics and electrodynamics in an analytic way. In order to set up fully explicit solutions. In order to apply the quaternionic operator calculus to solve these types of boundary value problems fully explicitly, one has to evaluate two types of integral operators: the Teodorescu operator and the quaternionic Bergman projector. While the integral kernel of the Teodorescu transform is universal for all domains, the kernel function of the Bergman projector, called the Bergman kernel, depends on the geometry of the domain. Recently the theory of quaternionic holomorphic multiperiodic functions and automorphic forms provided new impulses to set up explicit representation formulas for large classes of hyperbolic polyhedron type domains. These include block shaped domains, wedge shaped domains (with or without additional rectangular restrictions) and circular symmetric finite and infinite cylinders as particular subcases. In this talk we want to give an overview over the recent developments in this direction.
The reduction of oscillation amplitudes of structural elements is necessary not only for maintenance of their durability and longevity but also for elimination of a harmful effect of oscillations on people and technology operations. The dampers are widely applied for this purpose. One of the most widespread models of structural friction forces having piecewise linear relation to displacement was analysed. T The author suggests the application of phase trajectories mapping in plane "acceleration – displacement". Unlike the trajectories mapping in a plane "velocity – displacement", they don't require large number of geometrical constructions for identification of the characteristics of dynamic systems. It promotes improving the accuracy. The analytical assumptions had been verified by numerical modeling. The results show good enough coincide between numerical and analytical estimation of dissipative characteristic.
We propose a new approach to the numerical solution of quasi-static elastic-plastic problems based on the Moreau-Yosida theorem. After the time discretization, the problem is expressed as an energy minimization problem for unknown displacement and plastic strain fields. The dependency of the minimization functional on the displacement is smooth whereas the dependency on the plastic strain is non-smooth. Besides, there exists an explicit formula, how to calculate the plastic strain from a given displacement field. This allows us to reformulate the original problem as a minimization problem in the displacement only. Using the Moreau-Yosida theorem from the convex analysis, the minimization functional in the displacements turns out to be Frechet-differentiable, although the hidden dependency on the plastic strain is non-differentiable. The seconds derivative exists everywhere apart from the elastic-plastic interface dividing elastic and plastic zones of the continuum. This motivates to implement a Newton-like method, which converges super-linearly as can be observed in our numerical experiments.
Die meisten Insolvenzen in Deutschland kommen aus der Bauindustrie. Die Gründe hierfür sind vielschichtig, jedoch kann mittels eines modern ausgerichteten M-I-S und Baustellen-Controllings frühzeitig erkannt werden, wie sich die Baustellenergebnisse entwickeln. Hierzu ist es notwendig, dass die Arbeitskalkulation ständig auf dem Laufenden gehalten wird. Nur wenn dies geschieht, sind monatliche Soll-/ Ist-Vergleiche und eine Betrachtung der cost-to-complete möglich und sinnvoll. Eine monatlich rollierende Prognose des Baustellenergebnisses zum Bauende ermöglicht, dass gravierende Veränderungen des Ergebnisses umgehend aufgedeckt werden. Nur in Kenntnis dieser Entwicklungen kann das Management frühzeitig (im Sinne eines Frühwarnsystems) agieren und Steuerungsmaßnahmen ergreifen. Die Ergebnisprognose zum Bauende ist allein als Steuerungsinstrument nicht ausreichend. Die Finanzsituation der Baustelle muß auch regelmäßig geprüft werden, d.h. der Leistungsstand mit der Rechnungsstellung an den Bauherren abgeglichen sowie die unbezahlten Rechnungen des Bauherren überprüft werden. Das beste Prognoseergebnis ist wertlos, wenn der Bauherr seine bezogenen Leistungen nicht vergütet. Die wirtschaftlichen Daten stehen den Verantwortlichen online im Baustellen-Informations-System (B-I-S) zur Verfügung. Ein Ampelsystem verdeutlicht die wirtschaftliche Lage der Baustelle.
This research focuses on the Case-based Reasoning paradigm in architectural design (CBD) and education. Initial point for further exploring this only seemingly comprehensive investigated field of research constitutes the finding that promising looking concepts exist but that they do not play a role in daily routine of designing architects or in university education. In search of reasons for this limited success a critical review of the CBR approach to architectural education and design was performed. The aim was to identify gaps in the CBD research and to discover potential fields of research within CBR research in architectural education and design to improve acceptance and practical suitability. Two major shortcomings could be identified. In the first place the way retrieval mechanisms of systems under investigation relate to the needs of architectural designers and students. At second: Successful CBD systems rely on the work of third-parties in sharing their experiences with others and filling the databases with relevant cases. Therefore two questions remain unanswered: The question of which projects become part of the database and how get existing projects not only described but evaluated. This is an essential task and prerequisite to meet the requirements of the underlying theory of CBR.
In civil engineering practice, values of column forces are often required before any detailed analysis of the structure has been performed. One of the reasons for this arises from the fast-tracked nature of the majority of construction projects: foundations are laid and base columns constructed whilst analysis and design are still in progress. A need for quick results when feasibility studies are performed or when evaluating the effect of design changes on supporting columns form other situations in which column forces are required, but where a detailed analysis to get these forces seems superfluous. Thus it was concluded that the development of an efficient tool for column force calculations, in which the extensive input required in a finite element analysis is to be avoided, would be highly beneficial. The automation of the process is achieved by making use of a Voronoi diagram. The Voronoi diagram is used a) for subdividing the floor into influence areas and b) as a basis for automatic load assignment. The implemented procedure is integrated into a CAD system in which the relevant geometric information of the floor, i.e. its shape and column layout, can be defined or uploaded. A brief description of the implementation is included. Some comparative results and considerations regarding the continuation of the study are given.
Hinsichtlich der Integration einzelner Bauwerkslebensphasen und der verschiedenen Beteiligten, insbesondere innerhalb von Bauplanungs- und Revitalisierungsprozessen, bestehen aktuell entscheidende Defizite. Die generelle Zielstellung der in diesem Beitrag vorgestellten Forschungsarbeiten besteht in der Unterstützung und Verbesserung der Integration durch die disziplin- und lebensphasenübergreifende Bereitstellung sämtlicher bauwerksbezogener Informationen. Dies erfordert einerseits geeignete Ansätze zur Modellierung und Integration der vielfältigen disziplinspezifischen Daten, andererseits geeignete Lösungen, die einen globalen Zugriff, Navigation und Recherche im Gesamtdatenbestand ermöglichen. Die Modellierung und Verwaltung bauwerksbezogener Daten ist seit längerem Gegenstand diverser Forschungsarbeiten. Im Rahmen des SFB 524 wurde ein eigener Ansatz basierend auf einem laufzeitdynamischen Partialmodellverbund entwickelt. Dieser wird in den wesentlichen Grundzügen anderen Ansätzen gegenübergestellt. Den Schwerpunkt dieses Beitrags bildet jedoch die Entwicklung einer geeigneten flexiblen Navigations- und Rechercheschicht zu Realisierung projektglobaler Informationsrecherche. Aus der Sicht der Modellierung und Datenverwaltung wie auch aus der Sicht der Informationsrecherche und Informationspräsentation in Planungsprozessen ergeben sich verschiedene Anforderungen an derartige Recherchewerkzeuge, wobei der wesentlichste Grundsatz maximale Flexibilität hinsichtlich verfügbarer Darstellungstechniken und deren freie Kombination mit Techniken formaler Suchanfragen ist. Das entwickelte Systemkonzept basiert auf einem Framework, welches verschiedene Grundtypen von Recherchemodulen und deren Interaktionsprinzipien vorgibt. Einzelne Recherchemodule werden als Ausprägungen dieser Modultypen realisiert und können je nach Bedarf laufzeitdynamisch in die Navigationsschicht integriert werden. Die technische Realisierung des Systems erfolgt im Umfeld vorhandener Prototypen aus vorangegangenen Forschungsaktivitäten. Dieses technische Umfeld gibt verschiedene Rahmenbedingungen vor, welche im Vorfeld prototypischer Implementierungen verschiedene Adaptionen des generellen Systemkonzepts notwendig machen. Der vorliegende Beitrag stellt den aktuellen Entwicklungsstand der Systemlösung aus konzeptioneller und technischer Sicht sowie erste prototypische Realisierungen von Recherchemodulen vor.
Prozesse im Bauingenieurwesen sind komplex und beinhalten eine große Anzahl verschiedener Aufgaben mit vielen logischen Abhängigkeiten. Basierend auf diesen projektspezifischen Abhängigkeiten wird gewöhnlich ein Bauablaufplan manuell erstellt. In der Regel existieren mehrere Varianten und somit alternative Bauabläufe um ein Projekt zu realisieren. Welche dieser Ausführungsvarianten zur praktischen Anwendung kommt, wird durch den jeweiligen Projektmanager bestimmt. Falls Ä;nderungen oder Störungen während des Bauablaufs auftreten, müssen die davon betroffenen Aufgaben und Abläufe per Hand modifiziert und alternative Aufgaben sowie Abläufe stattdessen ausgeführt werden. Diese Vorgehensweise ist oft sehr aufwändig und teuer. Aktuelle Forschungsansätze beschäftigen sich mit der automatischen Generierung von Bauabläufen. Grundlage sind dabei Aufgaben mit ihren erforderlichen Voraussetzungen und erzeugten Ergebnissen. Im Rahmen dieses Beitrags wird eine Methodik vorgestellt, um Bauabläufe mit Ausführungsvarianten in Form von Workflow-Netzen zu jeder Zeit berechnen zu können. Die vorgestellte Methode wird anhand eines Beispiels aus dem Straßenbau schematisch dargestellt.
In this paper we study the structure of the solutions to higher dimensional Dirac type equations generalizing the known λ-hyperholomorphic functions, where λ is a complex parameter. The structure of the solutions to the system of partial differential equations (D- λ) f=0 show a close connection with Bessel functions of first kind with complex argument. The more general system of partial differential equations that is considered in this paper combines Dirac and Euler operators and emphasizes the role of the Bessel functions. However, contrary to the simplest case, one gets now Bessel functions of any arbitrary complex order.
Car following models are used to describe the behavior of a number of cars on the road dependent on the distance to the car in front. We introduce a system of ordinary differential equations and perform a theoretical and numerical analysis in order to find solutions that reflect various traffic situations. We present three different variations of the model motivated by reality.
Image processing has been much inspired by the human vision, in particular with regard to early vision. The latter refers to the earliest stage of visual processing responsible for the measurement of local structures such as points, lines, edges and textures in order to facilitate subsequent interpretation of these structures in higher stages (known as high level vision) of the human visual system. This low level visual computation is carried out by cells of the primary visual cortex. The receptive field profiles of these cells can be interpreted as the impulse responses of the cells, which are then considered as filters. According to the Gaussian derivative theory, the receptive field profiles of the human visual system can be approximated quite well by derivatives of Gaussians. Two mathematical models suggested for these receptive field profiles are on the one hand the Gabor model and on the other hand the Hermite model which is based on analysis filters of the Hermite transform. The Hermite filters are derivatives of Gaussians, while Gabor filters, which are defined as harmonic modulations of Gaussians, provide a good approximation to these derivatives. It is important to note that, even if the Gabor model is more widely used than the Hermite model, the latter offers some advantages like being an orthogonal basis and having better match to experimental physiological data. In our earlier research both filter models, Gabor and Hermite, have been developed in the framework of Clifford analysis. Clifford analysis offers a direct, elegant and powerful generalization to higher dimension of the theory of holomorphic functions in the complex plane. In this paper we expose the construction of the Hermite and Gabor filters, both in the classical and in the Clifford analysis framework. We also generalize the concept of complex Gaussian derivative filters to the Clifford analysis setting. Moreover, we present further properties of the Clifford-Gabor filters, such as their relationship with other types of Gabor filters and their localization in the spatial and in the frequency domain formalized by the uncertainty principle.
Reasonably accurate cost estimation of the structural system is quite desirable at the early stages of the design process of a construction project. However, the numerous interactions among the many cost-variables make the prediction difficult. Artificial neural networks (ANN) and case-based reasoning (CBR) are reported to overcome this difficulty. This paper presents a comparison of CBR and ANN augmented by genetic algorithms (GA) conducted by using spreadsheet simulations. GA was used to determine the optimum weights for the ANN and CBR models. The cost data of twenty-nine actual cases of residential building projects were used as an example application. Two different sets of cases were randomly selected from the data set for training and testing purposes. Prediction rates of 84% in the GA/CBR study and 89% in the GA/ANN study were obtained. The advantages and disadvantages of the two approaches are discussed in the light of the experiments and the findings. It appears that GA/ANN is a more suitable model for this example of cost estimation where the prediction of numerical values is required and only a limited number of cases exist. The integration of GA into CBR and ANN in a spreadsheet format is likely to improve the prediction rates.
In this paper proposed the application of two-parameters damage model, based on non-linear finite element approach, to the analysis of masonry panels. Masonry is treated as a homogenized material, for which the material characteristics can be defined by using homogenization technique. The masonry panels subjected to shear loading are studied by using the proposed procedure within the framework of three-dimensional analyses. The nonlinear behaviour of masonry can be modelled using concepts of damage theory. In this case an adequate damage function is defined for taking into account different response of masonry under tension and compression states. Cracking can, therefore, be interpreted as a local damage effect, defined by the evolution of known material parameters and by one or several functions which control the onset and evolution of damage. The model takes into account all the important aspects which should be considered in the nonlinear analysis of masonry structures such as the effect of stiffness degradation due to mechanical effects and the problem of objectivity of the results with respect to the finite element mesh. Finally the proposed damage model is validated with a comparison with experimental results available in the literature.
The idea about a simulation program to support urban planning is explained: Four different, clearly defined developing paths can be calculated for the rebuilding of a shrinking town. Aided by self-organization principles, a complex system can be created. The dynamics based on the action patterns of single actors, whose behaviour is cyclically depends on the generated structure. Global influences, which control the development, can be divided at a spatial, socioeconomic, and organizational-juridical level. The simulation model should offer conclusions on new planning strategies, especially in the context of the creation process of rebuilding measures. An example of a transportation system is shown by means of prototypes for the visualisation of the dynamic development process.
Für eine gesicherte Planung im Bestand, sind eine Fülle verschiedenster Informationen zu berücksichtigen, welche oft erst während des Planungs- oder Bauprozesses gewonnen werden. Voraussetzung hierfür bildet immer eine Bestandserfassung. Zwar existieren Computerprogramme zur Unterstützung der Bestandserfassung, allerdings handelt es sich hierbei ausschließlich um Insellösungen. Der Export der aufgenommenen Daten in ein Planungssystem bedingt Informationsverluste. Trotz der potentiellen Möglichkeit aktueller CAAD/BIM Systeme zur Verwaltung von Bestandsdaten, sind diese vorrangig für die Neubauplanung konzipiert. Die durchgängige Bearbeitung von Sanierungsprojekten von der Erfassung des Bestandes über die Entwurfs- und Genehmigungsplanung bis zur Ausführungsplanung innerhalb eines CAAD/BIM Systems wird derzeit nicht adäquat unterstützt. An der Professur Informatik in der Architektur (InfAR) der Fakultät Architektur der Bauhaus-Universität Weimar entstanden im Rahmen des DFG Sonderforschungsbereich 524 "Werkzeuge und Konstruktionen für die Revitalisierung von Bauwerken" in den letzten Jahren Konzepte und Prototypen zur fachlich orientierten Unterstützung der Planung im Bestand. Der Fokus lag dabei in der Erfassung aller planungsrelevanter Bestandsdaten und der Abbildung dieser in einem dynamischen Bauwerksmodell. Aufbauend auf diesen Forschungsarbeiten befasst sich der Artikel mit der kontextbezogenen Weiterverwendung und gezielten Bereitstellung von Bestandsdaten im Prozess des Planens im Bestand und der Integration von Konzepten der planungsrelevanten Bestandserfassung in marktübliche CAAD/BIM Systeme.
Die Kommunale Wohnungsgesellschaft mbH Erfurt(KoWo) ist mit ihren rund 20.000 Wohnungen in der Landeshauptstadt das größte Wohnungsunternehmen in Thüringen. Der Immobilienbestand ist heterogen in seinem technischen Zustand und im Bezug auf die unterschiedlichen Lagen der Objekte. Bedingt durch Leerstände und unterschiedliche Modernisierungsmaßnahmen und -stände unterscheidet sich die Wirtschaftlichkeit verschiedener Objekte deutlich. Ohne eine einheitliche Einwertung des Immobilienbestandes im Bezug auf die Objektattraktivität, die Standortqualität und die Objektwirtschaftlichkeit fällt eine langfristige strategische Entwicklung des Immobilienportfolios schwer. Über die Schritte der technischen Bestandserfassung, die Einwertung über ein Scorintmodell, die Abbildung in einem Portfoliomodell mit zugehöriger Normstrategie bis hin zur Weiterverarbeitung der Daten in der 20-jährigen Instandsetzungsplanung wird praxisnah aufgezeigt, wie die Vorgehensweise bei der Einwertung des Immobilienportfolios ist.
Unconstrained models are very often found in the broad spectrum of different theories of traffic demand models. In these models there are none or only one-sided restrictions influencing the choice of the individual. However in the traffic demand different deciding dependencies of the traffic volume with regard to the specific conditions of the territory structure potentials exist. Kichhoff and Lohse introduced bi- and tri-linearly constrained models to show these dependencies. In principle, the dependencies are described as hard, elastic and open boundary sum criteria. In this article a model is formulated which gets away from these predefined boundary sum criteria and allows a free determination of minimal and maximal boundary sum criteria. The iterative solution algorithm is shown according to a FURNESS procedure at the same time. With the approach of freely selectable minimal and maximal boundary sum criteria the modeling transport planner gets the possibility to show the traffic event even better. Furthermore all common boundary sum criteria can be calculated with this model. Therewith the often necessary and sensible standard and special cases can also be modeled.
Practical examples show that the improvement in cost flow and total amount of money spend in construction and further use may be cut significantly. The calculation is based on spreadsheets calculation, very easy to develop on most PC´s now a days. Construction works, are a field where the evaluation of Cash Flow can be and should be applied. Decisions about cash flow in construction are decisions with long-term impact and long-term memory. Mistakes from the distant past have a massive impact on situations in the present and into the far economic future of economic activities. Two approaches exist. The Just-in-Time (JIT) approach and life cycle costs (LCC) approach. The calculation example shows the dynamic results for the production speed in opposition to stable flow of production in duration of activities. More sophisticated rescheduling in optimal solution might bring in return extra profit. In the technologies and organizational processes for industrial buildings, railways and road reconstruction, public utilities and housing developments there are assembly procedures that are very appropriate for the given purpose, complicated research-, development-, innovation-projects are all very good aspects of these kinds of applications. The investors of large investments and all public invested money may be spent more efficiently if an optimisation speed-strategy can be calculated.
The design of challenging space structures frequently relies on the theory of folded plates. The models are composed of plane facets of which the bending and membrane stiffness are coupled along the folds. In conventional finite element analysis of faceted structures the continuity of the displacement field is enforced exclusively at the nodes. Since approximate solutions for transverse and for in-plane displacements are not members of the same function space, separation occurs in between the common nodes of adjacent elements. It is shown that the kinematic assumptions of Bernoulli are accounted for this incompatibility along the edges in facet models. A general answer to this problem involves substantial modification of plate and membrane theory, but a straight forward formulation can be derived for simply folded plates, structures, whose folds do not intersect. A broad class of faceted structures, including models of various curved shells, belong to this category and can be calculated consistently. The additional requirements to assure continuity concern the mapping of displacement derivatives on the edges. An appropriate finite facet element provides node and edge-oriented degrees of freedom, whose transformation to system degrees of freedom, depends on the geometric configuration at each node. The concept is implemented using conform triangular elements. To evaluate the new approach, the energy norm of representative structures for refined meshes is calculated. The focus is placed on the mathematical convergence towards reliable solutions obtained from finite volume models.
The present paper is part of a comprehensive approach of grid-based modelling. This approach includes geometrical modelling by pixel or voxel models, advanced multiphase B-spline finite elements of variable order and fast iterative solver methods based on the multigrid method. So far, we have only presented these grid-based methods in connection with linear elastic analysis of heterogeneous materials. Damage simulation demands further considerations. The direct stress solution of standard bilinear finite elements is severly defective, especially along material interfaces. Besides achieving objective constitutive modelling, various nonlocal formulations are applied to improve the stress solution. Such a corrective data processing can either refer to input data in terms of Young's modulus or to the attained finite element stress solution, as well as to a combination of both. A damage-controlled sequentially linear analysis is applied in connection with an isotropic damage law. Essentially by a high resolution of the heterogeneous solid, local isotropic damage on the material subscale allows to simulate complex damage topologies such as cracks. Therefore anisotropic degradation of a material sample can be simulated. Based on an effectively secantial global stiffness the analysis is numerically stable. The iteration step size is controlled for an adequate simulation of the damage path. This requires many steps, but in the iterative solution process each new step starts with the solution of the prior step. Therefore this method is quite effective. The present paper provides an introduction of the proposed concept for a stable simulation of damage in heterogeneous solids.
DECENTRALIZED APPROACHES TO ADAPTIVE TRAFFIC CONTROL AND AN EXTENDED LEVEL OF SERVICE CONCEPT
(2006)
Traffic systems are highly complex multi-component systems suffering from instabilities and non-linear dynamics, including chaos. This is caused by the non-linearity of interactions, delays, and fluctuations, which can trigger phenomena such as stop-and-go waves, noise-induced breakdowns, or slower-is-faster effects. The recently upcoming information and communication technologies (ICT) promise new solutions leading from the classical, centralized control to decentralized approaches in the sense of collective (swarm) intelligence and ad hoc networks. An interesting application field is adaptive, self-organized traffic control in urban road networks. We present control principles that allow one to reach a self-organized synchronization of traffic lights. Furthermore, vehicles will become automatic traffic state detection, data management, and communication centers when forming ad hoc networks through inter-vehicle communication (IVC). We discuss the mechanisms and the efficiency of message propagation on freeways by short-range communication. Our main focus is on future adaptive cruise control systems (ACC), which will not only increase the comfort and safety of car passengers, but also enhance the stability of traffic flows and the capacity of the road (“traffic assistance”). We present an automated driving strategy that adapts the operation mode of an ACC system to the autonomously detected, local traffic situation. The impact on the traffic dynamics is investigated by means of a multi-lane microscopic traffic simulation. The simulation scenarios illustrate the efficiency of the proposed driving strategy. Already an ACC equipment level of 10% improves the traffic flow quality and reduces the travel times for the drivers drastically due to delaying or preventing a breakdown of the traffic flow. For the evaluation of the resulting traffic quality, we have recently developed an extended level of service concept (ELOS). We demonstrate our concept on the basis of travel times as the most important variable for a user-oriented quality of service.
DIGITAL SUPPORT OF MATERIAL- AND PRODUCT SELECTION IN THE ARCHITECTURAL DESIGN- AND PLANNING PROCESS
(2006)
Architecture is predominantly perceived over the surfaces limiting the space. The used surface materials thereby should support the design intention and have to fulfil various technical and economical requirements. If the architect wants to select the "right" or the "best" material he has to play with very different and sometimes contradicting criteria and must weight these individually for the special purpose. This selection process is supported only insufficiently by today's digital systems. If it would be possible to illustrate all the various parameters by numerical values, the method of multidimensional scaling will offer a solution for architects to find the material which is best fitting on basis of his individual weighting of criteria. By displaying the result of the architect's multidimensional query in a spatial arrangement multidimensional scaling can support an interactive selection process with additional feedback over the applied search strategy.
The extended finite element method (XFEM) offers an elegant tool to model material discontinuities and cracks within a regular mesh, so that the element edges do not necessarily coincide with the discontinuities. This allows the modeling of propagating cracks without the requirement to adapt the mesh incrementally. Using a regular mesh offers the advantage, that simple refinement strategies based on the quadtree data structure can be used to refine the mesh in regions, that require a high mesh density. An additional benefit of the XFEM is, that the transmission of cohesive forces through a crack can be modeled in a straightforward way without introducing additional interface elements. Finally different criteria for the determination of the crack propagation angle are investigated and applied to numerical tests of cracked concrete specimens, which are compared with experimental results.
The aim of this paper is to present so-called discrete-continual boundary element method (DCBEM) of structural analysis. Its field of application comprises buildings constructions, structures and also parts and components for the residential, commercial and un-inhabitant structures with invariability of physical and geometrical parameters in some dimensions. We should mention here in particular such objects as beams, thin-walled bars, strip foundations, plates, shells, deep beams, high-rise buildings, extensional buildings, pipelines, rails, dams and others. DCBEM comes under group of semianalytical methods. Semianalytical formulations are contemporary mathematical models which currently becoming available for realization due to substantial speed-up of computer productivity. DCBEM is based on the theory of the pseudodifferential boundary equations. Corresponding pseudodifferential operators are discretely approximated using Fourier analysis or wavelet analysis. The main DCBEM advantages against the other methods of the numerical analysis is a double reduction in dimension of the problem (discrete numerical division applied not to the full region of the interest but only to the boundary of the region cross section, as a matter of fact one is solving an one-dimensional problem with the finite step on the boundary area of the region), one has opportunities to carrying out very detailed analysis of the specific chosen zones, simplified initial data preparation, simplistic and adaptive algorithms. There are two methods to define and conduct DCBEM analysis developed – indirect (IDCBEM) and direct (DDCBEM), thus indirect like in boundary element method (BEM) applied and used little bit more than direct.
Designing a structure follows a pattern of creating a structural design concept, executing a finite element analysis and developing a design model. A project was undertaken to create computer support for executing these tasks within a collaborative environment. This study focuses on developing a software architecture that integrates the various structural design aspects into a seamless functional collaboratory that satisfies engineering practice requirements. The collaboratory is to support both homogeneous collaboration i.e. between users operating on the same model and heterogeneous collaboration i.e. between users operating on different model types. Collaboration can take place synchronously or asynchronously, and the information exchange is done either at the granularity of objects or at the granularity of models. The objective is to determine from practicing engineers which configurations they regard as best and what features are essential for working in a collaborative environment. Based on the suggestions of these engineers a specification of a collaboration configuration that satisfies engineering practice requirements will be developed.
The use of process models in the analysis, optimization and simulation of processes has proven to be extremely beneficial in the instances where they could be applied appropriately. However, the Architecture/Engineering/Construction (AEC) industries present unique challenges that complicate the modeling of their processes. A simple Engineering process model, based on the specification of Tasks, Datasets, Persons and Tools, and certain relations between them, have been developed, and its advantages over conventional techniques have been illustrated. Graph theory is used as the mathematical foundation mapping Tasks, Datasets, Persons and Tools to vertices and the relations between them to edges forming a directed graph. The acceptance of process modeling in AEC industries not only depends on the results it can provide, but the ease at which these results can be attained. Specifying a complex AEC process model is a dynamic exercise that is characterized by many modifications over the process model's lifespan. This article looks at reducing specification complexity, reducing the probability for erroneous input and allowing consistent model modification. Furthermore, the problem of resource leveling is discussed. Engineering projects are often executed with limited resources and determining the impact of such restrictions on the sequence of Tasks is important. Resource Leveling concerns itself with these restrictions caused by limited resources. This article looks at using Task shifting strategies to find a near-optimal sequence of Tasks that guarantees consistent Dataset evolution while resolving resource restrictions.
This is an implementation of the Fillmore–Springer–Cnops construction (FSCc) based on the Clifford algebra capacities of the GiNaC computer algebra system. FSCc linearises the linear-fraction action of the Mobius group. This turns to be very useful in several theoretical and applied fields including engineering. The core of this realisation of FSCc is done for an arbitrary dimension, while a subclass for two dimensional cycles add some 2D-specific routines including a visualisation to PostScript files through the MetaPost or Asymptote software. This library is a backbone of many result published in, which serve as illustrations of its usage. It can be ported (with various level of required changes) to other CAS with Clifford algebras capabilities.
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.
Objects for civil engineering applications can be identified with their reference in memory, their alpha-numeric name or their geometric location. Particularly in graphic user interfaces, it is common to identify objects geometrically by selection with the mouse. As the number of geometric objects in a graphic user interface grows, it becomes increasingly more important to treat the basic operations add, search and remove for geometric objects with great efficiency. Guttmann has proposed the Region-Tree (R-tree) for geometric identification in an environment which uses pages on disc as data structure. Minimal bounding rectangles are used to structure the data in such a way that neighborhood relations can be described effectively. The literature shows that the parameters which influence the efficiency of the R-trees have been studied extensively, but without conclusive results. The goal of the research which is reported in this paper is to determine reliably the parameters which significantly influence the efficiency of R-trees for geometric identification in technical drawings. In order to make this investigation conclusive, it must be performed with the best available software technology. Therefore an object-oriented software for the method is developed. This implementation is tested with technical drawings containing many thousands of geometric objects. These drawings are created automatically by a stochastic generator which is incorporated into a test bed consisting of an editor and a visualisor. This test bed is used to obtain statistics for the main factors which affect the efficiency of R-trees. The investigation shows that the following main factors which affect the efficiency can be identified reliably : number of geometric objects on the drawing the minimum und maximum number of children of a node of the tree the maximum width and height of the minimal bounding rectangles of the geometric objects relative to the size of the drawing.
The one-dimensional continuous wavelet transform is a successful tool for signal and image analysis, with applications in physics and engineering. Clifford analysis offers an appropriate framework for taking wavelets to higher dimension. In the usual orthogonal case Clifford analysis focusses on monogenic functions, i.e. null solutions of the rotation invariant vector valued Dirac operator ∂, defined in terms of an orthogonal basis for the quadratic space Rm underlying the construction of the Clifford algebra R0,m. An intrinsic feature of this function theory is that it encompasses all dimensions at once, as opposed to a tensorial approach with products of one-dimensional phenomena. This has allowed for a very specific construction of higher dimensional wavelets and the development of the corresponding theory, based on generalizations of classical orthogonal polynomials on the real line, such as the radial Clifford-Hermite polynomials introduced by Sommen. In this paper, we pass to the Hermitian Clifford setting, i.e. we let the same set of generators produce the complex Clifford algebra C2n (with even dimension), which we equip with a Hermitian conjugation and a Hermitian inner product. Hermitian Clifford analysis then focusses on the null solutions of two mutually conjugate Hermitian Dirac operators which are invariant under the action of the unitary group. In this setting we construct new Clifford-Hermite polynomials, starting in a natural way from a Rodrigues formula which now involves both Dirac operators mentioned. Due to the specific features of the Hermitian setting, four different types of polynomials are obtained, two types of even degree and two types of odd degree. These polynomials are used to introduce a new continuous wavelet transform, after thorough investigation of all necessary properties of the involved polynomials, the mother wavelet and the associated family of wavelet kernels.
Mit diesen Ausführungen wird ein Beitrag zum weiteren Erhalt der historischen Bausubstanz in Mecklenburg aus der Sicht der Tragwerksanalyse geleistet. Dabei bestätigt es sich immer mehr, dass mit dem Modell der Geometrie, der Belastung und des Materials gleichberechtigte Modelle für eine wirklichkeitsnahe Einschätzung des Tragverhaltens eines Tragwerks vorliegen müssen. Es zeigt sich, dass dabei die besten Berechnungsprogramme nur die Ergebnisse liefern können, die mit den Eingabedaten zu erzielen sind. So hat sich der Forschungsschwerpunkt im Lehrgebiet Tragwerkslehre des FB Architektur an der Hochschule Wismar in den letzten Jahren auf die realistische Abbildung der Wechselwirkung zwischen der Bauaufnahme und der geometrischen Modellierung konzentriert. In diesem Bereich zeigen sich als Schwerpunkte die Wechselwirkung zwischen Schäden und Tragwerksanalyse und die Wechselwirkung zwischen der aufgenommenen Geometrie und dem geometrischen Modell für die Tragwerksanalyse. Die Fülle der aufgenommenen Daten sind dabei in der Regel mehr hinderlich als ein Segen für die Tragwerksanalyse. Hier wurde gezeigt, welche und wie viele geometrische Daten für das geometrische Modell für die Tragwerksanalyse sinnvoll sind. Da die eigene Datenaufnahme relativ viel Zeit beansprucht, wurde eine "geistige" Bauaufnahme durchgeführt. Dazu wird der historische Planungsprozess in den einzelnen Formfindungsschritten nachvollzogen und in die virtuelle Realität überführt. Mit dieser Methode ergeben sich unterschiedliche Bauzustände und es lassen sich auch mögliche Bauphasen abbilden. Die Tragwerksanalyse dieser virtuellen Realität zeigt dann mögliche Schwächen der Tragwerke und/oder die Notwendigkeit konstruktiver Veränderungen. Ein Vergleich der Ergebnisse der Tragwerksanalyse mit der Realität anhand des vorliegenden Datenbestands liefert die Grundlage für den aktuellen Handlungsbedarf. Da der Bauzustand eines Bauwerkes unter einer zeitlichen Veränderung steht, werden Methoden überprüft, die es ermöglichen, einen einmal vorgelegten Datenbestand aufzubereiten und weiter zu verwalten.
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.
Solid behavior as well as liquid behavior characterizes the flow of granular material in silos. The presented model is based on an appropriate interaction of a displacement field and a velocity field. The constitutive equations and the applied algorithm are developed from the exact solution for a standard case. The standard case evolves from a very tall vertical plane strain silo containing material that flows at a constant speed. No horizontal displacements and velocities take place. No changes regarding the field values arise in the vertical direction and in time. Tension is not allowed at any point. Coulomb friction represents the effects of the vertical walls. The interaction between the flowing material and the walls is covered by a forced boundary condition resulting in an additional matrix for the solid component as well as for the liquid component. The resulting integral equations are designed to be solved directly. Three coefficients describe the properties of the granular material. They govern elastic solid behavior in combination with viscous liquid behavior.
HYPERMONOGENIC POLYNOMIALS
(2006)
It is well know that the power function is not monogenic. There are basically two ways to include the power function into the set of solutions: The hypermonogenic functions or holomorphic Cliffordian functions. L. Pernas has found out the dimension of the space of homogenous holomorphic Cliffordian polynomials of degree m, but his approach did not include a basis. It is known that the hypermonogenic functions are included in the space of holomorphic Cliffordian functions. As our main result we show that we can construct a basis for the right module of homogeneous holomorphic Cliffordian polynomials of degree m using hypermonogenic polynomials and their derivatives. To that end we first recall the function spaces of monogenic, hypermonogenic and holomorphic Cliffordian functions and give the results needed in the proof of our main theorem. We list some basic polynomials and their properties for the various function spaces. In particular, we consider recursive formulas, rules of differentiation and properties of linear independency for the polynomials.
Water resources development and management is a complex problem. It includes the design and operation of single system components, often as part of larger interrelated systems and usually on the basis of river basins. While several decades ago the dominant objective was the maximization of economic benefit, other objectives have evolved as part of the sustainable development envisaged. Today, planning and operation of larger water resources systems is practically impossible without adequate computer tools, normally being one or several models, increasingly combined with data bank management systems and multi criteria assessment procedures in decision support systems. The use of models in civil engineering already has a long history when structural engineering is considered. These design support models, however, must rather be seen as expert systems made to support the engineer with his daily work. They often have no direct link to stakeholders and the decision makers community. The scale of investigation is often much larger in water resources engineering than in structural engineering which is related to different stakeholders and decision making procedures. Still, several similarities are obvious which can be summarized as the search for a compromise solution on a complex, i.e. multiobjective and interdisciplinary decision problem. While in structural engineering e.g. aestetics, stability and energy consumption might be important evaluation criteria in addition to construction and maintenance cost other or additional criteria have to be considered in water resources planning such as political, environmental and social criteria. In this respect civil engineers tend to overemphasize technical criteria. For the future the existing expert systems should be embedded into an improved decision support shell, keeping in mind that decision makers are hardly interested in numerical modelling results. The paper will introduce into the problem and demonstrate the state of the art by means of an example.
A concept for integrated modeling of urban and rural hydrology is introduced. The concept allows for simulations on the catchment scale as well as on the local scale. It is based on a 2-layer-approach which facilitates the parallel coupling of a catchment hydrology model with an urban hydrology model, considering the interactions between the two systems. The concept has been implemented in a computer model combining a grid based distributed hydrological catchment model and a hydrological urban stormwater model based on elementary units. The combined model provides a flexible solution for time and spatial scale integration and offers to calculate separate water balances for urban and rural hydrology. Furthermore, it is GIS-based which allows for easy and accurate geo-referencing of urban overflow structures, which are considered as points of interactions between the two hydrologic systems. Due to the two-layer-approach, programs of measures can be incorporated in each system separately. The capabilities of the combined model have been tested on a hypothetical test case and a real world application. It could be shown that the model is capable of accurately quantifying the effects of urbanization in a catchment. The affects of urbanization can be analyzed at the catchment outlet, but can also be traced back to its origins, due to the geo-referencing of urban overflow structures. This is a mayor advantage over conventional hydrological catchment models for the analysis of land use changes.
Räume und Gebäude sind heute wegen der enormen Funktionalität der technischen Gebäudeausrüstung (TGA) in Kombination mit der sonstigen Ausstattung und den diversen Anwendungsprozessen und Nutzergruppen ohne innovative Konzepte der integrierten Bedienung kaum noch beherrschbar bzw. optimal nutzbar. Dies gilt sowohl für Wohn- als auch für Zweckimmobilien. Die Gebäudeleittechnik (GLT) und die Gebäudeautomation (GA) können hier unter sinnvoller Integration der Möglichkeiten der Mikroelektronik, Multimedia-, Kommunikations- und Informationstechnik erheblich zu nutzbringenden Innovationen beitragen. Die Automobilindustrie hat in den letzten Jahren gezeigt, wie durch einen integralen Systemansatz und durch Einsatz von Elektronik, Kommunikations- und Informationstechnik eine sinnvolle technische Assistenz der Anwender machbar ist. Genannt sei hier das Konzept des Cockpits mit integrierter Funktionsbündelung und der Informationskonzentration am Armaturenbrett. Im Gegensatz zum Automobil ist der Bereich der technischen Gebäudeausstattung in Wohn- und Nutzimmobilien gekennzeichnet durch eine starke Fragmentierung in unterschiedlichste Gewerke unter Beteiligung vieler oft schlecht koordinierter Akteure. Durch das Duisburger inHaus-Innovationszentrum für Intelligente Raum- und Gebäudesysteme der Fraunhofer-Gesellschaft wurden in den letzten Jahren neuartige Konzepte der Systemintegration heterogener Technik auf der Basis von Middleware-Plattformen und Multimedia-Technologien und -Geräten entwickelt, getestet und in die Anwendung getragen. Einer der ersten Systemanwendungen dieses offenen Infrastrukturkonzepts ist die integrierte Systembedienung mit zum Teil völlig neuen Bedienkonzepten und einer starken Bedienungsvereinfachung auch komplexester Technikausrüstungen in Immobilien. Der Beitrag beschreibt nach einer Analyse der Ausgangslage die technologischen Grundzüge der integrierten Systembedienung. Es folgen einige Anwendungsbeispiele und eine zusammenfassende Bewertung mit einem Ausblick auf weiterführende Aktivitäten.
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.
The design and application of high performance materials demands extensive knowledge of the materials damage behavior, which significantly depends on the meso- and microstructural complexity. Numerical simulations of crack growth on multiple length scales are promising tools to understand the damage phenomena in complex materials. In polycrystalline materials it has been observed that the grain boundary decohesion is one important mechanism that leads to micro crack initiation. Following this observation the paper presents a polycrystal mesoscale model consisting of grains with orthotropic material behavior and cohesive interfaces along grain boundaries, which is able to reproduce the crack initiation and propagation along grain boundaries in polycrystalline materials. With respect to the importance of modeling the geometry of the grain structure an advanced Voronoi algorithm is proposed to generate realistic polycrystalline material structures based on measured grain size distribution. The polycrystal model is applied to investigate the crack initiation and propagation in statically loaded representative volume elements of aluminum on the mesoscale without the necessity of initial damage definition. Future research work is planned to include the mesoscale model into a multiscale model for the damage analysis in polycrystalline materials.
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.
In this study we introduce a concept of discrete Laplacian on the plane lattice and consider its iteration dynamical system. At first we discuss some basic properties on the dynamical system to be proved. Next making their computer simulations, we show that we can realize the following phenomena quite well:(1) The crystal of waters (2) The designs of carpets, embroideries (3) The time change of the numbers of families of extinct animals, and (4) The echo systems of life things. Hence we may expect that we can understand the evolutions and self organizations by use of the dynamical systems. Here we want to make a stress on the following fact: Although several well known chaotic dynamical systems can describe chaotic phenomena, they have difficulties in the descriptions of the evolutions and self organizations.
Für eine beherrschbare Koordination und Durchführung von Planungsaufgaben in Bauprojekten wird der Planungsprozess zunehmend in formalisierten Modellen – Prozessmodellen – beschrieben. Die Produktmodellforschung ihrerseits widmet sich der Speicherung von Planungsdaten in Form von objektorientierten Modellen im Rechner. Hauptaugenmerk sind dabei die Wahrung der Konsistenz und die Modellierung von Abhängigkeiten innerhalb dieses Planungsmaterials. Der Bezug zu den Akteuren der Planung wird nicht direkt hergestellt. Ein formal beschriebener Planungsprozesses kann in der Praxis noch nicht derart realisiert werden, dass ein Zugriff auf Einzelobjekte des Planungsprozesses gewährleistet ist. Bestehende Planungsunterstützungs- und Workflowmanagement-Systeme abstrahieren und ordnen das Planungsmaterial nach wie vor auf Dateiebene. Der vorliegende Artikel beschreibt eine Methode für die geeignete Verbindung von formalisierten Prozessmodellen in der Bauplanung mit den Einzelobjekten, die in den modellorientierten Objektmengen kodiert sind. Dabei wird die Zugehörigkeit bestimmter Objekte zu Plänen und Dokumenten (zum Zwecke des Datenaustauschs) nicht länger durch die physische Zuordnung zu Dateien festgelegt. Es wird ein formales Beschreibungsmittel vorgestellt, welches die entsprechende Teilmengenbildung aus der Gesamtheit der Planungsobjekte ermöglicht. Für die bisherigen Formen des Datenaustausches werden aus den Objektmodellen der Planung Teilmengen herausgelöst und physikalisch zwischen den Planern transportiert. Das neue Beschreibungsmittel hingegen erlaubt es, die Bildungsvorschrift für Objektteilmengen statt der Mengen selbst zwischen den Planern auszutauschen. Der Zugriff auf die konkreten Objekte findet dann direkt modellbasiert statt.