Tomasz Arciszewski

Evolutionary Computation in Structural Design

The paper provides the results of preliminary research on the application of evolutionary computation to integrated structural design in which a complex design support tool automatically conducts both conceptual and detailed design. In the paper, a brief overview of the state of the art in evolutionary computation and its applications to structural design is provided. Next, Inventor 2000 is described, a unique research and structural design tool developed by the authors at George Mason University that combines an evolutionary computation component with a system for wind forces analysis, and a system for the analysis, design and optimisation of steel structures. The paper also presents the results of four structural design experiments conducted with Inventor 2000. The objective of experiments was to investigate various forms of evolutionary computation as applied to structure design. Finally, the paper provides the initial research conclusions and recommendations for further research.

A methodology of design knowledge acquisition for use in learning expert systems

Abstract This paper presents an approach to design conceptual knowledge acquisition. The approach was basically developed for knowledge acquisition in BRZDY1, a learning expert system for conceptual design currently under development. A formal identification of qualitative, conceptual design decisions, based on typology by coverings and the description of design problems by qualitative variables, is discussed. Also, we describe the fundamentals of the method of generating design rules from examples of decisions made by an expert. This method is based on the extended concept of rough set. A comprehensive example of the application of this method to conceptual design of steel members under bending is provided at the end of the paper.

Bio-inspiration: learning creative design principia

Reusing or modifying known design concepts cannot meet new challenges facing engineering systems. However, engineers can find inspiration outside their traditional domains in order to develop novel design concepts. The key to progress and knowledge acquisition is found in inspiration from diverse domains. This paper explores abstract knowledge acquisition for use in conceptual design. This is accomplished by considering body armor in nature and that developed in Europe in the last Millennium. The research is conducted in the context of evolution patterns of the Directed Evolution Method, which is briefly described. The focus is on conceptual inspiration. Analysis results of historic and natural body armor evolution are described and two sets of acquired creative design principia from both domains are presented. These principia can be used to stimulate human development of novel design concepts. Creative design principia, combined with human creativity, may lead to revolutionarychanges, rather than merely evolutionarysteps, in the evolution of engineering systems.

Inferential Design Theory: A Conceptual Outline

This paper presents initial ideas toward a new design theory based on the Inferential Theory of Learning, recently developed in artificial intelligence. The theory views engineering design as a process of transforming the initial design specification and design background knowledge into the desired design. This process is performed using certain knowledge operators called ‘knowledge transmutations.’ Nine basic tenets of the theory are provided, and a system of 22 design knowledge transmutations is proposed. Individual transmutations are defined and explained using examples from the area of conceptual design of wind bracings in steel skeleton structures of tall buildings. The paper also contains initial conclusions and a discussion of future research.

Morphogenic Evolutionary Design: Cellular Automata Representations in Topological Structural Design

This paper provides the initial results of a study on the applications of cellular automata representations in evolutionary design of topologies of steel structural systems in tall buildings. In the paper, a brief overview of the state of the art in cellular automata and evolutionary design representations is presented. Next, morphogenic evolutionary design is introduced and illustrated by several types of cellular automata representations. Further, Emergent Designer, a unique evolutionary design tool developed at George Mason University, is briefly described. It is an integrated research and design support tool which applies models of complex adaptive systems to represent engineering systems and analyze design processes. The paper also reports the initial results of several structural design experiments conducted with Emergent Designer. The objective of the experiments was to determine feasibility of various types of cellular automata representations in topological structural optimization. Finally, initial research conclusions and recommendations for the further research are provided.

Design Fixation: A Cloak of Many Colors

The term design fixation is often used interchangeably to refer to situations where designers limit their creative output because of an overreliance on features of preexisting designs, or more generally, an overreliance on a specific body of knowledge directly associated with a problem. In this paper, we argue that interdisciplinary interest in design fixation has led to increasingly broad definitions of the phenomenon which may be undermining empirical research efforts, educational efforts to minimize fixation, and the transdisciplinary distribution of knowledge about fixation effects. To address these issues, the authors recommend that researchers consider categorizing fixation phenomena into one of three classifications: unconscious adherence to the influence of prior designs, conscious blocks to change, and intentional resistance to new ideas. Next, we distinguish between concept-based design fixation, fixation to a specific class of known design concepts, and knowledge-based design fixation, fixation to a problem-specific knowledge base. With these distinctions in place, we propose a system of orders of design fixation, recommend methods for reducing fixation in inventive design, and recommend areas that are in need of further research within the field of design science.

Morphogenesis and structural design: cellular automata representations of steel structures in tall buildings

This paper provides the initial results of a study on the application of generative cellular, automata-based representations in evolutionary structural design. First, recent developments in evolutionary design representations and an overview of cellular automata are presented. Next, a complex problem of topological design of steel structural systems in tall buildings is briefly described. Further, morphogenic evolutionary design is introduced and exemplified by cellular automata representations. The paper also reports the initial results of several structural design experiments whose objective was to determine feasibility of the proposed approach. Finally, initial research conclusions are provided.

A Tool for the Conceptual Design of Production and Operations Systems

This paper proposes a conceptual design tool, based upon inferential design theory. It has been specifically developed for the design of production and operations systems, but its use can be extended to other engineering areas, such as mechanical and structural systems. Inferential design theory and its foundation in the inferential theory of learning are briefly outlined. Both theories are based on the idea of using specialised knowledge operators in learning and design, termed knowledge transmutations and design knowledge transmutations respectively. The 24 transmutations existing in the two theories are outlined, and a further 12 design-specific transmutations are proposed. These have been developed as a result of our research. A conceptual design process is proposed, in which design knowledge transmutations are used. A software tool for design, CREDO, is also described and an example of its use in the generation of design concepts for an after-sales service facility is presented. The conclusions discuss the initial methodological experience of using CREDO to generate design concepts. They are based on the introductory use of CREDO at Technion in Israel for teaching purposes. Directions for further research are also provided.

Evolutionary multiobjective optimization of steel structural systems in tall buildings

This paper presents results of extensive computational experiments in which evolutionary multiobjective algorithms were used to find Pareto-optimal solutions to a complex structural design problem. In particular, Strength-Pareto Evolutionary Algorithm 2 (SPEA2) was combined with a mathematical programming method to find optimal designs of steel structural systems in tall buildings with respect to two objectives (both minimized): the total weight and the maximum horizontal displacement of a tall building. SPEA2 was employed to determine Pareto-optimal topologies of structural members (topology optimization) whose cross-sections were subsequently optimized by the mathematical programming method (sizing optimization). The paper also presents the shape of the Pareto front in this two-dimensional objective space and discusses its dependence on the buildings aspect ratio. The results reported provide both qualitative and quantitative knowledge regarding the relationship between the two objectives. They also show the trade-offs involved in the process of conceptual and detailed design of complex structural systems in tall buildings.

Multiobjective evolutionary design of steel structures in tall buildings

This paper presents initial results of a study on the application of evolutionary multiobjective optimization methods in the design of the steel structural systems of tall buildings. In the paper, a brief overview of the state-of-the-art in evolutionary multi-objective optimization in structural engineering is provided. Next, conceptual design of steel structural systems in tall buildings is overviewed and the representations of steel structural systems used in the paper are discussed. Furthermore, Emergent Designer, a unique evolutionary design tool developed at George Mason University, is briefly described. It is an integrated research and design support tool which applies models of complex adaptive systems to represent engineering systems and to analyze design processes and their results. The paper also presents the results of several multi-objective structural design experiments conducted with Emergent Designer in which steel structural systems in tall buildings were optimized with respect to their total weight and maximum deflection (two-objective minimization problem). The goal of these experiments was to determine feasibility of evolutionary multi-objective optimization of steel structural systems of tall buildings as well as to qualitatively and quantitatively compare the results with the previous findings obtained with single-objective evolutionary optimization methods. Finally, initial research conclusions are presented as well as promising research directions.