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Anhand von Ergebnissen aus dem FABEL-Projekt wird gezeigt, welche Beiträge Methoden der Künstlichen Intelligenz, insbesondere der Wissensverarbeitung beim Entwurf komplexer Gebäude leisten können. Exemplarisch werden spezialisierte wissensintensive Methoden, und allgemeine fallbasierte Methoden zum Retrieval und zur Wiederverwendung früherer Entwürfe vorgestellt. Es werden Fragen der Integration von Wissen, Fällen und Daten diskutiert. Der Prototyp des FABEL-Projekts verwendet die Metapher der virtuellen Baustelle, um die verschiedenen Methoden als Planungswerkzeuge in einem CAD-System integriert anzubieten. Ein Planungsmodell dient der zusätzlichen Orientierung des Planers. Die Ergebnisse sind interessant für den Entwurf komplexer Unikate, dürften aber auch als Zusatz zu elektronisch angebotenen Katalogen relevant sein.
This is a paper about knowledge in design and how to elicit knowledge from design processes. The paper is a preparation for an empirical study of interaction in the design process. Reasonings of three authors - Schön, Broadbent and Lundequist - on design processes is presented. They all have a pragmatic perspective in common, and regard the process as an activity without a definite form. Design is seen as an activity of creating models of forms and shapes, by addressing expert knowledge in a dialogic way to problematic situations. Due to the pragmatic approach I find the pragmatist Dewey´s understanding of knowledge and elecitation of knowledge appropiate for studying design processes. According to him it is possible to build up objectified descriptions of experiences, also of such, which are based on experiences of emotional and intuitive nature. There need not be a definite border, which separates tacit knowledge from explicit knowledge - when it comes to the question of the possibility of verbal descriptions. Tacit knowledge is possible to articulate within pragmatic thinking. The conclusion is, that it is possible to study the tacit knowledge of design processes, and get some qualitative insights useful for theory building. A study of design processes can look at three different forms of knowledge. It appears as a precognitive understanding of the design situation, as integrated in the design activity - seeing the situation as something known - and in the process of creating something new.
Die effektive Kooperation aller beteiligten Fachplaner im Bauplanungsprozess ist die Voraussetzung für wirtschaftliches und qualitativ hochwertiges Bauen. Bauprojektorganisationen bestehen in der Regel aus zahlreichen unabhängigen Planungspartnern, die örtlich verteilt spezifische Planungsaufgaben bearbeiten und die Ergebnisse in Teilproduktmodellen ablegen. Da Planungsprozesse im Bauwesen stark arbeitsteilig ablaufen, sind die Teilproduktmodelle der einzelnen Fachplanungen in hohem Maße voneinander abhängig. Ziel des hier vorgestellten Ansatzes ist die Integration der Teilproduktmodelle der Gebäudeplanung in einem netzwerkbasierten Modellverbund am Beispiel der Brandschutzplanung. Im Beitrag werden die Probleme der Verteiltheit und insbesondere der semantischen Heterogenität der involvierten Teilproduktmodelle betrachtet. Der verteilte Zugriff wird mithilfe mobiler Software-Agenten realisiert. Die Agenten können sich dabei frei im netzwerkbasierten Planungsverbund bewegen und agieren als Vertreter der Fachplaner. Das Problem der semantischen Heterogenität der Teilproduktmodelle wird auf der Basis von Ontologien gelöst. Dazu werden erstens Domänenontologien entwickelt, die Objekte der realen Welt einer abgeschlossenen Domäne, hier des Brandschutzes, abbilden. Zweitens werden Applikationsontologien entwickelt, die die einzelnen proprietären Datenhaltungen (im Sinne von Teilproduktmodellen) der jeweiligen Fachplanungen repräsentieren. Beide Ontologien werden mit einem regelbasierten Ansatz verknüpft. Im vorgestellten Anwendungsfall Brandschutz dient die Domänenontologie als einheitliche Schnittstelle für den Zugriff auf die verteilten Modelle und abstrahiert dabei von deren Datenbankspezifika und proprietären Schemata. Mithilfe von mobilen Agenten und semantischen Technologien kann so eine Plattform zur Verfügung gestellt werden, die erstens die dynamische Integration von Ressourcen in den Planungsverbund erlaubt und zweitens auf deren Basis unabhängig von der Verteiltheit und Heterogenität der eingebundenen Ressourcen ingenieurgerechte Verarbeitungsmethoden realisiert werden können.
Optimum technological solutions must take into account the entire life cycle of structures including design procedures as well as quality assurance, inspection, maintenance, and repair strategies. Unfortunately, current design standards do not provide a satisfactory basis to ensure expected structural lifetimes. The latter may vary from only a few years for temporary structures to over a century for bridges, water dams or nuclear repositories. Consistent scientific concepts are urgently required to cover this wide spectrum of lifetimes in structural design and maintenance. This was a motivation for a group of scientists at the Ruhr-University Bochum (RUB) to start a special research program supported by the German Research Foundation (DFG) within the Cooperative Research Center SFB 398 since 1996. Institutes of the University Wuppertal and of the University Essen-Duisburg joined the research group. The goal of the Center is to study sources of damage and deterioration in materials and structures, to develop consistent models and simulation methods, to predict structural lifetimes and finally to integrate this predictions into new lifetime-oriented design strategies.
Research activities in our center are organised in three Project Groups as follows:
- Modelling of lifetime effects
- Methods for lifetime-oriented structural analyses
- Future lifespan-oriented design strategies.
LIFETIME-ORIENTED OPTIMIZATION OF BRIDGE TIE RODS EXPOSED TO VORTEX-INDUCED ACROSS-WIND VIBRATIONS
(2006)
In recent years, damages in welded connections plates of vertical tie rods of several arched steel bridges have been reported. These damages are due to fatigue caused by wind-induced vibrations. In the present study, such phenomena are examined, and the corresponding lifetime of a reference bridge in Münster-Hiltrup, Germany, is estimated, based on the actual shape of the connection plate. Also, the results obtained are compared to the expected lifetime of a connection plate, whose geometry has been optimized separately. The structural optimization, focussing on the shape of the cut at the hanger ends, has been carried out using evolution strategies. The oscillation amplitudes have been computed by means of the Newmark-Wilson time-step method, using an appropriate load model, which has been validated by on-site experiments on the selected reference bridge. Corresponding stress-amplitudes are evaluated by multiplying the oscillation amplitudes with a stress concentration factor. This factor has been computed on the basis of a finite element model of the system "hanger-welding-connection plate", applying solid elements, according to the notch stress approach. The damage estimation takes into account the stochastics of the exciting wind process, as well as the stochastics of the material parameters (fatigue strength) given in terms of Woehler-curves. The shape optimization results in a substantial increase of the estimated hanger lifetime. The comparison of the lifetimes of the bulk plate and of the welding revealed that, in the optimized structure, the welding, being the most sensitive part in the original structure, shows much more resistance against potential damages than the bulk material.
Die Liquiditätsplanung von Bauunternehmen XE "Liquiditätsplanung" gilt als ein wesentliches Steuerungs-, Kontroll- sowie Informationsinstrument für interne und externe Adressaten und übt eine Entscheidungsunterstützungsfunktion aus. Da die einzelnen Bauprojekte einen wesentlichen Anteil an den Gesamtkosten des Unternehmens ausmachen, besitzen diese auch einen erheblichen Einfluß auf die Liquidität und die Zahlungsfähigkeit der Bauunternehmung. Dem folgend ist es in der Baupraxis eine übliche Verfahrensweise, die Liquiditätsplanung zuerst projektbezogen zu erstellen und anschließend auf Unternehmensebene zu verdichten. Ziel der Ausführungen ist es, die Zusammenhänge von Arbeitskalkulation XE "Arbeitskalkulation" , Ergebnisrechnung XE "Ergebnisrechnung" und Finanzrechnung XE "Finanzrechnung" in Form eines deterministischen XE "Erklärungsmodells" Planungsmodells auf Projektebene darzustellen. Hierbei soll das Verständnis und die Bedeutung der Verknüpfungen zwischen dem technisch-orientierten Bauablauf und dessen Darstellung im Rechnungs- und Finanzwesen herausgestellt werden. Die Vorgänge aus der Bauabwicklung, das heißt die Abarbeitung der Bauleistungsverzeichnispositionen und deren zeitliche Darstellung in einem Bauzeitenplan sind periodisiert in Größen der Betriebsbuchhaltung (Leistung, Kosten) zu transformieren und anschließend in der Finanzrechnung (Einzahlungen., Auszahlungen) nach Kreditoren und Debitoren aufzuschlüsseln.
This paper presents results of applying Fuzzy Inference System for estimation of the number of potential Park and Ride users. Usually it is difficult to evaluate the number of users because it depends on human factor and data in the considered system are uncertain. In such situation the traditional mathematical approaches can not take into consideration rough data. Therefore a fuzzy approach can be applied in this case. A fuzzy methodology is treated as a proper way to describe choice of mode of transport, and especially that uncertainty accompanied of choosing process has rather fuzzy character. The proposed approach is based on the Mamdani Fuzzy Inference System and for calculation there is used Matlab software with Fuzzy Logic Toolbox. Mamdani model requires, as an input data, knowledge of the shape of membership function. These functions can be calibrated taking into consideration results of questionnaires conducted among users of Park and Ride system. Due to lack of representative sample of users, one has decided to use results of experts' questionnaires as a input data for calibration the shape of membership functions. Describing factor will be generalized cost of the trip for different modes of transport. Proposed approach consists of two main stages: modeling of share of public/private transport trips and Multimodal model estimating number of Park and Ride users. Verification of presented methodology is treated as an indirect proof. Proposed approach can be applied for estimation of bi-modal split. Then the results are compared with traditional approaches based on logit functions. Comparable results of proposed fuzzy approach with traditional logit models can be treated as a confirmation of chosen methodology.
At the 16th IKM Bock, Falcão and Gürlebeck presented examples of the application of some specially developed Maple-Software in hypercomplex analysis. Other papers of those authors continued this work and showed the efficiency of such tools for concrete numerical calculations as well as for numerical experiments, supporting the detection of new relationships and even theorems in a highly technical theoretical work. The mentioned software has been developed mainly for the use on mapping problems in the Euclidean spaces of dimension 3 and 4 by means of Bergman kernel methods (BKM), which are related to monogenic functions as solutions of generalized Cauchy-Riemann equations with respect to the Euclidean metric (Riesz system). The developed procedures concerning generalized powers of totally regular variables and the corresponding homogeneous polynomials basically rely on results and conventions introduced in the paper "Power series representation for monogenic functions in Rm+1 based on a permutational product", Complex Variables, 15, No.3, 181-191 (1990) by H. Malonek. Since 1992 H. Leutwiler, S. L. Eriksson and others developed in a number of papers a modified Clifford analysis and, particularly, a modified quaternionic analysis. The modification mainly consists in considering generalized Cauchy-Riemann equations with respect to a hyperbolic metric in a half space. The aim of this contribution is to show how through a change of the basic combinatorial relations used in the modified quaternionic analysis the aforementioned Maple-software (that has been recently published on CD-Rom as integrated part of the text book "Funktionentheorie in der Ebene und im Raum" by K. Gürlebeck, K. Habetha, and W. Sprössig, in the series "Grundstudium Mathematik" of Birkhäuser Verlag, 2006) can directly be used for numerical calculations in the modified theory.
The paper contains a description of dynamic effects in the silo wall during the outflow of a stored material. The work allows for determining the danger of construction damage due to resonant vibrations and is of practical importance by determining the influence of cyclic pressures and vibro–creeping during prolonged use of a silo. The paper was devised as a result of tests on silo walls in semi-technical scale. The model is generally applicable and allows for identification of parameters in real- size silos as well.
The paper is a proposal of calculation of internal forces and dislocations in the reinforced concrete beams before and after cracking. For the ideally elastic bars transfer matrix proposed by Rakowski was applied. The effects associated with cracking were introduced by means of the Borcz's theory in the spectrally way. Numerical example was shown. The presented attitude also enables to calculate dynamic problems and those connected with the stability of the compressed and bending cracked beams and columns.