Bodo Kraft

Visual knowledge specification for conceptual design: Definition and tool support

Current CAD tools are not able to support the conceptual design phase, and none of them provides a consistency analysis for sketches produced by architects. This phase is fundamental and crucial for the whole design and construction process of a building. To give architects a better support, we developed a CAD tool for conceptual design and a knowledge specification tool. The knowledge is specific to one class of buildings and it can be reused. Based on a dynamic and domain-specific knowledge ontology, different types of design rules formalize this knowledge in a graph-based form. An expressive visual language provides a user-friendly, human readable representation. Finally, a consistency analysis tool enables conceptual designs to be checked against this formal conceptual knowledge. In this article, we concentrate on the knowledge specification part. For that, we introduce the concepts and usage of a novel visual language and describe its semantics. To demonstrate the usability of our approach, two graph-based visual tools for knowledge specification and conceptual design are explained.

Parameterized Specification of Conceptual Design Tools in Civil Engineering

In this paper we discuss how tools for conceptual design in civil engineering can be developed using graph transformation specifications. These tools consist of three parts: (a) for elaborating specific conceptual knowledge (knowledge engineer), (b) for working out conceptual design results (architect), and (c) automatic consistency analyses which guarantee that design results are consistent with the underlying specific conceptual knowledge. For the realization of such tools we use a machinery based on graph transformations.

Semantic Tool Support for Conceptual Design

When designing a building, an experienced architect implicitly applies his aggregated knowledge to the new sketch. In this early design phase, called conceptual design, most architects do not elaborate their sketches using a CAD system. They rather work with pencil and paper. Without being directly aware of, the architect considers design rules, functional requirements, economic and legal restrictions. Constructive elements, like walls, windows or doors are used with their conceptual meaning, namely to form organizational areas or rooms, to guarantee e.g. light and ventilation, or to ensure accessibility. These conceptual elements, therefore, form a functional view of the design structure which, however, is not explicitly defined. Existing CAD systems give no support for this creative conceptual design. There is no smooth transition to constructive design. The architect manually elaborates the constructive design, now using a CAD system. He replaces the functional elements of the sketch by constructive ones, e.g. ventilation by a window, the access by a door etc. The conceptual information he had in mind gets lost. Furthermore, there are many changes within the development process. E.g., if the client is not satisfied, the architect has to go back to the conceptual design. The modified conceptual data are lost again after the next transformation step. Such iterations are risky and expensive in terms of time and money.

VISUAL KNOWLEDGE SPECIFICATION FOR CONCEPTUAL DESIGN

Current CAD tools are not able to support the fundamental conceptual design phase, and none of them provides consistency analyses of sketches produced by architects . To give architects a greater support at the conceptual design phase, we develop a CAD tool for conceptual design and a knowledge specification tool allowing the definition of conceptually rel evant knowledge. The knowledge is specific to one class of buil dings and can be reused. Based on a dynamic knowledge model, different types of design rules formalize the know ledge in a graph-based realization. An expressive visual language provides a user-friendly, human readable representation. Finally, consistency analyses enable conceptual designs to be checked against this defined knowledge. In this paper we concentrate on the knowledge specification part of our project.

Graph Transformations for Dynamic Knowledge Processing

The conceptual design phase at the beginning of the building construction process is not adequately supported by any CAD-tool. Conceptual design support needs regarding two aspects: first, the architect must be able to develop conceptual sketches that provide abstraction from constructive details. Second, conceptually relevant knowledge should be available to check these conceptual sketches. The paper deals with knowledge to formalize for conceptual design. To enable domain experts formalizing knowledge, a graph-based specification is presented that allows the development of a domain ontology and design rules specific for one class of buildings at runtime. The provided tool support illustrates the introduced concepts and demonstrates the consistency analysis between knowledge and conceptual design.

Fujaba-Based Tool Development for eHome Systems

One of the main reasons preventing a wide application of eHome systems in practice is the effort needed to combine all appliances, necessary controller and infrastructure components to benefit from derived value-added services. The properties, dependencies, locations, and installation conditions have to be properly specified for this composition and its deployment. Due to the great variance in services and eHome configurations there is a need for tool support for eHome systems. In this paper we address the software development issues of such tools. In our approach we base the software development on graph rewriting language techniques. Based on our experience, we consider this approach as a possibility to improve the productivity of the eHome system tool development. With the aid of Fujaba, we created a model capable of specifying functions, devices, environments, and value-added services. Furthermore, we used Fujaba to create the activities as graph rewriting rules for model modifications. To apply the model and to carry out the actual specification for a particular eHome and particular appliances we generated the eHomeSpecificator tool from the model and its activities. This tool can serve as a base for a wider range of tools supporting eHome systems.

Tool Support for the Integration of Light-Weight Ontologies

In many areas of computer science ontologies become more and more important. The use of ontologies for domain modeling often brings up the issue of ontology integration. The task of merging several ontologies, covering specific subdomains, into one unified ontology has to be solved. Many approaches for ontology integration aim at automating the process of ontology alignment. However, a complete automation is not feasible, and user interaction is always required. Nevertheless, most ontology integration tools offer only very limited support for the interactive part of the integration process. In this paper, we present a novel approach for the interactive integration of ontologies. The result of the ontology integration is incrementally updated after each definition of a correspondence between ontology elements. The user is guided through the ontologies to be integrated. By restricting the possible user actions, the integrity of all defined correspondences is ensured by the tool we developed. We evaluated our tool by integrating different regulations concerning building design.

Algorithm and Tool for Ontology Integration Based on Graph Rewriting

Ontologies are often used to define concepts of certain application domains. Using knowledge from several different subdomains then requires the integration of the defined ontologies. Since ontology integration is a difficult task, there is a need for adequate tool support. In the ConDes project, we developed a knowledge-based support for the conceptual design phase in building engineering. Thereby the problem of ontology integration had to be solved. In this paper, we describe these tools and demonstrate how they support the integration task.

Semantic Roomobjects for Conceptual Design Support

The conceptual design at the beginning of the building construction process is essential for the success of a building project. Even if some CAD tools allow elaborating conceptual sketches, they rather focus on the shape of the building elements and not on their functionality. We introduce semantic roomobjects and roomlinks, by way of example to the CAD tool ArchiCAD. These extensions provide a basis for specifying the organisation and functionality of a building and free architects from being forced to directly produce detailed constructive sketches. Furthermore, we introduce consistency analyses of the conceptual sketch, based on an ontology containing conceptual relevant knowledge, specific to one class of buildings.

Conceptual Design Tools for Civil Engineering

This paper gives a brief overview of the tools we have developed to support conceptual design in civil engineering. Based on the UPGRADE framework, two applications, one for the knowledge engineer and another for architects allow to store domain specific knowledge and to use this knowledge during conceptual design. Consistency analyses check the design against the defined knowledge and inform the architect if rules are violated.