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The uniqueness and the long life cycle of buildings imply a dynamically modifiable building model. The technological foundation for the management of digital building models, a dynamic model management system (MMS), developed by our research group, allows to explicitly access and to modify the object model of the stored planning data. In this paper, the integration of constraints in digital building models will be shown. Constraints are conditions, which apply to the instances of domain model classes, and are defined by the user at runtime of the information system. For the expression of constraints, the Constraint Modelling Language (CML) has been developed and will be described in this paper. CML is a powerful, intuitively usable object-oriented language, which allows the expression of constraints at a high semantic level. A constrained-enabled MMS can verify, whether an instance fulfils the applying constraints. To ensure flexibility, the evaluation of constraints is not implicitly performed by the systems, but explicitly initiated by the user. A classification of constraint types and example usage scenarios are given.
The worldwide growth of communication networks and associated technologies provide the basic infrastructure for new ways of executing the engineering process. Collaboration amongst team members seperated in time and location is of particular importance. Two broad themes can be recognized in research pertaining to distributed collaboration. One theme focusses on the technical and technological aspects of distributed work, while the other emphasises human aspects thereof. The case of finite element structural analysis in a distributed collaboratory is examined in this paper. An approach is taken which has its roots in human aspects of the structural analysis task. Based on experience of how structural engineers currently approach and execute this task while utilising standard software designed for use on local workstations only, criteria are stated for a software architechture that could support collaborative structural analysis. Aspects of a pilot application and the results of qualitative performance measurements are discussed.
In the AEC (Architecture / Engineering / Construction) industry a number of individuals and organisations collaborate and work jointly on a construction project. The resulting consortium has large pool of expertise and experience and can be defined as a Virtual Organisation (VO) formed for the duration of the project. VOs are electronically networked organisations where IT and web based communication technology play an important role in coordinating various activities of these organisations. This paper describes the design, development and implementation of a Grid enabled application called the Product Supplier Catalogue Database (PSCD) which supports collaborative working in consortia. As part of the Grid-enabling process, specialised metadata is being developed to enable PSCD to effectively utilise Grid middleware such as Globus and Java CoG toolkits. We also describe our experience whilst designing, developing and deploying the security service of the application using the Globus Security Interface (GSI).
The conceptual structure of an application that can support the structural analysis task in a distributed collaboratory is described in (van Rooyen and Olivier 2004). The application described there has a standalone component for executing the finite element method on a local workstation in the absence of network access. This application is comparable to current, local workstation based finite element packages. However, it differs fundamentally from standard packages since the application itself, and its objects, are adapted to support distributed execution of the analysis task. Basic aspects of an object-oriented framework for the development of applications which can be used in similar distributed collaboratories are described in this paper. An important feature of this framework is its application-centred design. This means that an application can contain any number of engineering models, where the models are formed by the collection of objects according to semantic views within the application. This is achieved through very flexible classes Application and Model, which are described in detail. The advantages of the application-centred design approach is demonstrated with reference to the design of steel structures, where the finite element analysis model, member design model and connection design model interact to provide the required functionality.
Re-examination of the behaviour of structures can be necessary due to deterioration or changes in the traffic situation during their lifetime. The Finite Element Method (FEM) is widely used in order to accomplish numerical analysis. Considering the development of computer performance, more detailed FEM models can be analyzed, even on site, with mobile computers. To compensate the increasing amount of data needed for the model input, measures need to be taken to save time, by distributing the work. In order to provide consistency to the model, fedback data must be checked upon reception. A local wireless computer network of ultra-portable devices linked together with a computer can provide the coordination necessary for efficient parallel working. Based on a digital model consisting of all data gathered, structural modelling and numerical analysis are performed automatically. Thus, the user is released from the work that can be automatized and the time needed for the overall analysis of a structure is decreased.
This paper describes an ongoing research on the representation and reasoning about construction specifications, which is part of a bigger research project that aims at developing a formalism for automating the identification of deviations and defects on construction sites. We specifically describe the requirements on product and process models and an approach for representing and reasoning about construction specifications to enable automated detection and assessment of construction deviations and defects. This research builds on the previous research on modeling design specifications and extends and elaborates concept of contexts developed in that domain. The paper provides an overview of how the construction specifications are being modele d in this research and points out future steps that need to be accomplished to develop the envisioned automated deviation and defect detection system.
Although there are some good reasons to design engineering software as a stand-alone application for a single computer, there are also numerous possibilities for creating distributed engineering applications, in particular using the Internet. This paper presents some typical scenarios how engineering applications can benefit from including network capabilities. Also, some examples of Internet-based engineering applications are discussed to show how the concepts presented can be implemented.
Collaboration in AEC Design : Web-enabling Applications using Peer-to-Peer Office Communicator
(2004)
A market analysis conducted by Gartner Dataquest in August 2001 has shown the typical characteristics of the AEC design process. High volatility in membership of AEC design groups and members dispersed over several external offices is the common collaboration scenario. Membership is most times short lived, compared to the overall duration of the process. A technical solution has to take that into account by making joining and leaving a collaborative work group very easy. The modelling of roles of collaboration between group members must be based on a commonly understood principle like the publisher / subscriber model, where the individual that is responsible for the distribution of vital information is clear. Security issues and trust in the confidentiality of the system is a central concern for the acceptance of the system. Therefore, keeping the subset of data that will be published under the absolute control of the publisher is a must. This is not the case with server-based scenarios, sometimes even due to psychological reasons. A loosely bound Peer-to-Peer network offers advantages over a server-based solution, because of less administrative overhead and simple installation procedures. In a peer-to-peer environment, a publish/subscribe role model can be more easily implemented. The publish/subscribe model matches the way AEC processes are modelled in real world scenarios today, where legal proof of information exchange between external offices is of high importance. Workflow management systems for small to midsize companies of the AEC industry may adopt the peer-to-peer approach to collaboration in the future. Further investigations are being made on the research level (WINDS) by integrating the viewer and redlining application Collaborate! into a collaborative environment.
Structural engineering projects are increasingly organized in networked cooperations due to a permanently enlarged competition pressure and a high degree of complexity while performing the concurrent design activities. Software that intends to support such collaborative structural design processes implicates enormous requirements. In the course of our common research work, we analyzed the pros and cons of the application of both the peer-to-peer (University of Bonn) and multiagent architecture style (University of Bochum) within the field of collaborative structural design. In this paper, we join the benefits of both architecture styles in an integrated conceptual approach. We demonstrate the surplus value of the integrated multiagent–peer-to-peer approach by means of an example scenario in which several structural engineers are co-operatively designing the basic structural elements of an arched bridge, applying heterogeneous CAD systems.
The scientific transfer of key technology features to developing countries, together with adequate competence, localisation and adaptation, is the primary purpose of the proposed investigation. It is evident that introducing high-level CAD design and detailing will improve the planning process in developing countries. Successful utilization of applied information technology for the planning process, however, depends on the user-interface of individual software. Therefore, to open the great opportunity embedded in CAD software for clients globally, the language and character-set barrier of traditional user-interfaces must be overcome. A proposal for a research program is given here to address such issue in favour of global civil engineering.