Showing papers in "Ai Edam Artificial Intelligence for Engineering Design, Analysis and Manufacturing in 2011"

Teaching innovative design reasoning: How concept???knowledge theory can help overcome fixation effects

Abstract: How can we prepare engineering students to work collectively on innovative design issues, involving ill-defined, ???wicked??? problems? Recent works have emphasized the need for students to learn to combine divergent and convergent thinking in a collaborative, controlled manner. From this perspective, teaching must help them overcome four types of obstacles or ???fixation effects??? (FEs) that are found in the generation of alternatives, knowledge acquisition, collaborative creativity, and creativity processes. We begin by showing that teaching based on concept???knowledge (C-K) theory can help to manage FEs because it helps to clarify them and then to overcome them by providing means of action. We show that C-K theory can provide scaffolding to improve project-based learning (PBL), in what we call project-based critical learning (PBCL). PBCL helps students be critical and give due thought to the main issues in innovative design education: FEs. We illustrate the PBCL process with several cases and show precisely where the FEs appear and how students are able to overcome them. We conclude by discussing two main criteria of any teaching method, both of which are usually difficult to address in situations of innovative design teaching. First, can the method be evaluated? Second, is the chosen case ???realistic??? enough? We show that C-K-based PBCL can be rigorously evaluated by teachers, and we discuss the circumstances in which a C-K-based PBCL may or may not be realistic.

The impact of product configurators on lead times in engineering-oriented companies

Abstract: This paper presents a study of how the use of product configurators affects business processes of engineering-oriented companies. A literature study shows that only a minor part of product configuration research deals with the effects of product configuration, and that the ones that do are mostly vague when reporting the effects of configurator projects. Only six cases were identified, which provide estimates of the actual size of lead time reduction achieved from product configurators. To broaden this knowledge, this paper presents the results of a study of 14 companies concerning the impact of product configurators on business processes related to the creation of quotes and detailed product specifications. The study documents impressive results of the application of configurator technology. For example, in the data retrieved the use of configurators was estimated to have implied up to a 99.9% reduction of the quotation lead time with an average estimated reduction of 85.5%.

Spatial grammar implementation: From theory to useable software

Abstract: Currently available computer-aided design tools provide strong support for the later stages of product development processes where the structure and shape of the design have been fixed. Support for earlier stages of product development, when both the structure and shape of the design are still fluid, demands conceptual design tools that support designers' ways of thinking and working, and enhance creativity, for example, by offering design alternatives, difficult or not, possible without the use of such tools. The potential of spatial grammars as a technology to support such design tools has been demonstrated through experimental research prototypes since the 1970s. In this paper, we provide a review of recent spatial grammar implementations, which were presented in the Design Computing and Cognition 2010 workshop on which this paper is based, in the light of requirements for conceptual design tools and identify future research directions in both research and design education.

Grasping gestures: gesturing with physical artifacts

Abstract: Gestures play an important role in communication. They support the listener, who is trying to understand the speaker. However, they also support the speaker by facilitating the conceptualization and verbalization of messages and reducing cognitive load. Gestures thus play an important role in collaboration and also in problem-solving tasks. In human–computer interaction, gestures are also used to facilitate communication with digital applications, because their expressive nature can enable less constraining and more intuitive digital interactions than conventional user interfaces. Although gesture research in the social sciences typically considers empty-handed gestures, digital gesture interactions often make use of hand-held objects or touch surfaces to capture gestures that would be difficult to track in free space. In most cases, the physical objects used to make these gestures serve primarily as a means of sensing or input. In contrast, tangible interaction makes use of physical objects as embodiments of digital information. The physical objects in a tangible interface thus serve as representations as well as controls for the digital information they are associated with. Building on this concept, gesture interaction has the potential to make use of the physical properties of hand-held objects to enhance or change the functionality of the gestures made. In this paper, we look at the design opportunities that arise at the intersection of gesture and tangible interaction. We believe that gesturing while holding physical artifacts opens up a new interaction design space for collaborative digital applications that is largely unexplored. We provide a survey of gesture interaction work as it relates to tangible and touch interaction. Based on this survey, we define the design space of tangible gesture interaction as the use of physical devices for facilitating, supporting, enhancing, or tracking gestures people make for digital interaction purposes, and outline the design opportunities in this space.

Three-dimensional information exchange over the semantic web for the domain of architecture, engineering, and construction

Abstract: Three-dimensional (3-D) geometry can be described in many ways, with both a varying syntax and a varying semantics. As a result, several very diverse schemas and file formats can be deployed to describe geometry, depending on the application domain in question. In a multidisciplinary domain such as the domain of architecture, engineering, and construction, this range of specialized schemas makes file format conversions inevitable. The approach adopted by current conversion tools, however, often results in a loss of information, most often due to a "mistranslation" between different syntaxes and/or semantics, leading to errors and limitations in the design conception stage and to inefficiency due to the required remodeling efforts. An approach based on semantic web technology may reduce the loss of information significantly, leading to an improved processing of 3-D information and hence to an improved design practice in the architecture, engineering, and construction domain. This paper documents our investigation of the nature of this 3-D information conversion problem and how it may be encompassed using semantic web technology. In an exploratory double test case, we show how the specific deployment of semantic rule languages and an appropriate inference engine are to be adopted to improve this 3-D information exchange. It shows how semantic web technology allows the coexistence of diverse descriptions of the same 3-D information, interlinked through explicit conversion rules. Although only a simple example is used to document the process, and a more in-depth investigation is needed, the initial results indicate the suggested approach to be a useful alternative approach to obtain an improved 3-D information exchange.

Modeling and solving technical product configuration problems

Abstract: This paper describes and evaluates approaches to model and solve technical product configuration problems using different artificial intelligence methodologies. By means of a typical example, the benefits and limitations of different artificial intelligence methods are discussed and a flexible software architecture for integrating different solvers in a product configurator is proposed.

Adaptive attribute selection for configurator design via shapley value

Abstract: Configurators have been generally accepted as important tools to elicit customers' needs and find the matches between customers' requirements and company's offerings. With product configurators, product design is reduced to a series of selections of attribute values. However, it has been acknowledged that customers are not patient enough to configure a long list of attributes. Therefore, making every round of configuring process productive and hence reducing the number of inputs from customers are of substantial interest to academic and industry alike. In this paper, we present an efficient product configuration approach by incorporating Shapley value, which is a concept used in game theory, to estimate the usefulness of each attribute in the configurator design. This new method iteratively selects the most relevant attribute that can contribute most in terms of information content from the remaining pool of unspecified attributes. As a result from product providers' perspective, each round of configuration can best narrow down the choices with given amount of time. The selection of the next round query is based on the customer's decision on the previous rounds. The interactive process thus runs in an adaptive manner that different customers will have different query sequences. The probability ranking principle is also exploited to give product recommendation to truncate the configuration process so that customers will not be burdened with trivial selection of attributes. Analytical results and numerical examples are also used to exemplify and demonstrate the viability of the method.

A computational approach to biologically inspired design

Abstract: The natural world provides numerous cases for analogy and inspiration in engineering design. During the early stages of design, particularly during concept generation when several variants are created, biological systems can be used to inspire innovative solutions to a design problem. However, identifying and presenting the valuable knowledge from the biological domain to an engineering designer during concept generation is currently a somewhat disorganized process or requires extensive knowledge of the biological system. To circumvent the knowledge requirement problem, we developed a computational approach for discovering biological inspiration during the early stages of design that integrates with established function-based design methods. This research defines and formalizes the information identification and knowledge transfer processes that enable systematic development of biologically inspired designs. The framework that supports our computational design approach is provided along with an example of a smart flooring device to demonstrate the approach. Biologically inspired conceptual designs are presented and validated through a literature search and comparison to existing products.

An interactive, visual approach to developing and applying parametric three-dimensional spatial grammars

Abstract: Spatial grammars are rule based, generative systems for the specification of formal languages. Set and shape grammar formulations of spatial grammars enable the definition of spatial design languages and the creation of alternative designs. Since the introduction of the underlying formalism, they have been successfully applied to different domains including visual arts, architecture, and engineering. Although many spatial grammars exist on paper, only a few, limited spatial grammar systems have been computationally implemented to date; this is especially true for three-dimensional (3-D) systems. Most spatial grammars are hard-coded, that is, once implemented, the vocabulary and rules cannot be changed without reprogramming. This article presents a new approach and prototype implementation for a 3-D spatial grammar interpreter that enables interactive, visual development and application of grammar rules. The method is based on a set grammar that uses a set of parameterized primitives and includes the definition of nonparametric and parametric rules, as well as their automatic application. A method for the automatic matching of the left hand side of a rule in a current working shape, including defining parametric relations, is outlined. A prototype implementation is presented and used to illustrate the approach through three examples: the "kindergarten grammar," vehicle wheel rims, and cylinder cooling fins. This approach puts the creation and use of 3-D spatial grammars on a more general level and supports designers with facilitated definition and application of their own rules in a familiar computer-aided design environment without requiring programming.

The role of gesture in designing

Abstract: ThispaperintroducesthespecialissueofAIEDAMontheroleofgestureindesigning.Itstartswiththecontextofthepapers submitted and a summary of the papers accepted. We then introduce gesture studies, one of the two main domains with whichthisSpecialIssueisconcerned.Wedonotintroducedesignresearch:wesupposethereadersofAIEDAMarefamiliar with this domain. After this general introduction to the domain of gesture studies, we provide an overview of gestures in design, that is, the research environment of the papers in this Special Issue. We then discuss some dimensions on which these papers differ, as well as some on which they are related.

Automatic feature recognition using artificial neural networks to integrate design and manufacturing: Review of automatic feature recognition systems

Abstract: Feature technology is considered an essential tool for integrating design and manufacturing. Automatic feature recognition (AFR) has provided the greatest contribution to fully automated computer-aided process planning system development. The objective of this paper is to review approaches based on application of artificial neural networks for solving major AFR problems. The analysis presented in this paper shows which approaches are suitable for different individual applications and how far away we are from the formation of a general AFR algorithm.

An empirical study of the expressiveness of the functional basis

Abstract: Function models are frequently used in engineering design to describe the technical functions that a product performs. This paper investigates the use of the functional basis, a function vocabulary developed to aid in communication and archiving of product function information, in describing consumer products that have been decomposed, analyzed, modeled functionally, and stored in a Web-based design repository. The frequency of use of function terms and phrases in 11 graphical and 110 list-based representations in the repository is examined and used to analyze the organization and expressiveness of the functional basis and function models. Within the context of reverse engineering, we determined that the modeling resolution provided by the hierarchical levels, especially the tertiary level, is inadequate for function modeling; the tertiary terms are inappropriate for capturing sufficient details desired by modelers for archiving and reuse, and there is a need for a more expressive flow terms and flow qualifiers in the vocabulary. A critical comparison is also presented of two representations in the design repository: function structures and function lists. The conclusions are used to identify new research opportunities, including the extension of the vocabulary to incorporate flow qualifiers in addition to more expressive terms.

Variations in functional decomposition for an existing product: Experimental results

Abstract: This paper describes the findings of an experiment on how different engineers understand notions of function and functional breakdown in the context of design by modification. The experiment was conducted with a homogenous group of 20 design engineers, who had all received the same education. The subjects were asked to analyze how a hydraulic pump works and summarize their understanding in a function tree. The subjects were given either the hydraulic pump itself (with part of its casing removed) or a maintenance drawing that showed a section cut of the pump. This paper shows typical outputs of the designers. It discusses the different notions of function that the subjects had and the differences in the function trees they generated. The paper focuses an eight detailed analyses to show the range of approaches the subjects took.

Hierarchical structuring of layout problems in an interactive evolutionary layout system

Abstract: This paper focuses on computer-based generative methods for layout problems in architecture and urban planning with special regard for the hierarchical structuring of layout elements. The generation of layouts takes place using evolutionary algorithms, which are used to optimize the arrangement of elements in terms of overlapping within a given boundary and the topological relations between them. In this paper, the approach is extended by a data structure that facilitates the hierarchical organization of layout elements making it possible to structure and organize larger layout problems into subsets that can be solved in parallel. An important aspect for the applicability of such a system in the design process is an appropriate means of user interaction. This depends largely on the calculation speed of the system and the variety of viable solutions. These properties are evaluated for hierarchical as well as for nonhierarchical structured layout problems.

Using contexts to supervise a collaborative process

Abstract: This article describes an investigation into the feasibility of using contextual reasoning to monitor and supervise the collaborative work of several knowledge workers working together on a project. Managing large and complex projects is a difficult task that requires situational awareness by the project manager to be able to be proactive when possible and to react correctly in the presence of events. In complex projects, effective oversight of the project personnel and the progress of the project are essential in ensuring that project objectives are met. This is especially true of projects that require contributions from various experts, whose interaction may be limited to a Web-based collaborative tool. Such oversight is typically the job of a project manager who is tasked with avoiding cost overruns, shipment delays, and ensuring product effectiveness. We utilize context-based reasoning and contextual graphs as the tools of choice for implementing an agent that emulates the function of a competent project manager. We use rocket design and manufacture as the domain to evaluate our technique. We use a public domain rocket design software package developed by the National Aeronautics and Space Administration as a guide to the domain. The article describes the investigation, its results, and the related works in a collaborative design project.

Getting the point: The role of gesture in managing intersubjectivity in a design activity

Abstract: This paper illustrates the complexity of pointing as it is employed in a design workshop. Using the method of interaction analysis, we argue that pointing is not merely employed to index, locate, or fix reference to an object. It also constitutes a practice for reestablishing intersubjectivity and solving interactional trouble such as misunderstandings or disagreements by virtue of enlisting something as part of the participants’ shared experience. We use this analysis to discuss implications for how such practices might be supported with computer mediation, arguing for a “bricolage” approach to systems development that emphasizes the provision of resources for users to collaboratively negotiate the accomplishment of intersubjectivity rather than systems that try to support pointing as a specific gestural action.

Genetic fuzzy modeling of user perception of three-dimensional shapes

Abstract: Defining the aesthetic and emotional value of a product is an important consideration for its design. Furthermore, if several designers are faced with the task of creating an object that describes a certain emotion/perception (aggressive, soft, heavy, etc.), each is most likely to interpret the emotion/perception with different shapes composed of a set of different geometric features. The authors propose an automatic approach to formalize the relationships between geometric information of three-dimensional objects and the intended emotional content using fuzzy logic. In addition, the automatically generated fuzzy knowledge base was compared to the user's perceptions and to the manually constructed fuzzy knowledge base. The initial findings indicate that the approach is valid to formalize geometric information with perceptions and validate the author's manually developed fuzzy models.

Personalized diagnoses for inconsistent user requirements

Abstract: Knowledge-based configurators are supporting configuration tasks for complex products such as telecommunication systems, computers, or financial services. Product configurations have to fulfill the requirements articulated by the user and the constraints contained in the configuration knowledge base. If the user requirements are inconsistent with the constraints in the configuration knowledge base, users have to be supported in finding out a way from the no solution could be found dilemma. In this paper we introduce a new algorithm (PersDiag) that allows the determination of personalized diagnoses for inconsistent user requirements in knowledge-based configuration scenarios. We present the results of an empirical study that show the advantages of our approach in terms of prediction quality and efficiency.

Discovering implicit constraints in design

Abstract: Designers who are experts in a given design domain are well known to be able to Immediately focus on ???good designs,??? suggesting that they may have learned additional constraints while exploring the design space based on some functional aspects. These constraints, which are often implicit, result in a redefinition of the design space, and may be crucial for discovering chunks or interrelations among the design variables. Here we propose a machine-learning approach for discovering such constraints in supervised design tasks. We develop models for specifying design function in situations where the design has a given structure or embodiment, in terms of a set of performance metrics that evaluate a given design. The functionally feasible regions, which are those parts of the design space that demonstrate high levels of performance, can now be learned using any general purpose function approximator. We demonstrate this process using examples from the design of simple locking mechanisms, and as in human experience, we show that the quality of the constraints learned improves with greater exposure in the design space. Next, we consider changing the embodiment and suggest that similar embodiments may have similar abstractions. To explore convergence, we also investigate the variability in time and error rates where the experiential patterns are significantly different. In the process, we also consider the situation where certain functionally feasible regions may encode lower dimensional manifolds and how this may relate to cognitive chunking.

Solving the tool switching problem with memetic algorithms

Abstract: The tool switching problem (ToSP) is well known in the domain of flexible manufacturing systems. Given a reconfigurable machine, the ToSP amounts to scheduling a collection of jobs on this machine (each of them requiring a different set of tools to be completed), as well as the tools to be loaded/unloaded at each step to process these jobs, such that the total number of tool switches is minimized. Different exact and heuristic methods have been defined to deal with this problem. In this work, we focus on memetic approaches to this problem. To this end, we have considered a number of variants of three different local search techniques (hill climbing, tabu search, and simulated annealing), and embedded them in a permutational evolutionary algorithm. It is shown that the memetic algorithm endowed with steepest ascent hill climbing search yields the best results, performing synergistically better than its stand-alone constituents, and providing better results than the rest of the algorithms (including those returned by an effective ad hoc beam search heuristic defined in the literature for this problem).

Multimodal spatial data access for architecture design assistance

Abstract: We present a multimodal spatial data access framework designed to serve the informational and computational requirements of architectural design assistance systems that are intended to provide intelligent spatial decision support and analytical capabilities. The framework focuses on multiperspective semantics, qualitative and artifactual spatial abstractions, and industrial conformance and interoperability within the context of the industry foundation classes. The framework provides qualitative and cognitively adequate representational mechanisms, and the formal interpretation of the structural form of indoor spaces that are not directly provided by conventional computer-aided design based or quantitative models of space. We illustrate the manner in which these representations directly provide the spatial abstractions that are needed to enable the implementation of intelligent analytical capabilities in design assistance tools. We introduce the framework, and also provide detailed use cases that illustrate the usability of the framework and the manner of its utilization within architectural design assistance systems.

A declarative framework for work process configuration

Abstract: This article describes the technical principles and representation of a constraint-based configuration method for work processes. Methods developed for the configuration of modular systems comprising components have traditionally adopted a representation where the properties and compatibility requirements are expressed as constraints associated with individual components. However, this representation does not accurately capture constraints on paths and subprocesses and is therefore unsuitable for process configuration. This article extends established constraint-based configuration methods with a constraint language for specifying properties of execution paths in work processes. A framework for semiautomated process customization is presented. It integrates the extended constraint language with a metamodel of the work processes in an organization and allows to adapt generic work processes to fit the requirements of specific development projects. Heuristic search methods are applied to build valid process configurations by incrementally resolving constraint violations. The declarative framework facilitates the adaptation of abstract work processes as well as the validation and repair of existing processes. The approach was developed in the context of a real-world system of complex design and development processes where it was shown that significant process improvements and reduction in effort required to edit process models can be achieved.

Considering multiscale scenes to elucidate problems encumbering three-dimensional intellection and navigation

Abstract: Virtual three-dimensional (3-D) environments have become pervasive tools in a number of professional and recreational tasks. However, interacting with these environments can be challenging for users, especially as these environments increase in complexity and scale. In this paper, we argue that the design of 3-D interaction techniques is an ill-defined problem. This claim is elucidated through the context of data-rich and geometrically complex multiscale virtual 3-D environments, where unexpected factors can encumber intellection and navigation. We develop an abstract model to guide our discussion, which illustrates the cyclic relationship of understanding and navigating; a relationship that supports the iterative refinement of a consistent mental representation of the virtual environment. Finally, we highlight strategies to support the design of interactions in multiscale virtual environments, and propose general categories of research focus.

Using speech to identify gesture pen strokes in collaborative, multimodal device descriptions

Abstract: One challenge in building collaborative design tools that use speech and sketch input is distinguishing gesture pen strokes from those representing device structure, that is, object strokes. In previous work, we developed a gesture/object classifier that uses features computed from the pen strokes and the speech aligned with them. Experiments indicated that the speech features were the most important for distinguishing gestures, thus indicating the critical importance of the speech–sketch alignment. Consequently, we have developed a new alignment technique that employs a two-step process: the speech is first explicitly segmented (primarily into clauses), then the segments are aligned with the pen strokes. Our speech segmentation step is unique in that it uses sketch features for locating segment boundaries in multimodal dialog. In addition, it uses a single classifier to directly combine word-based, prosodic (pause), and sketch-based features. In the second step, segments are initially aligned with strokes based on temporal correlation, and then classifiers are used to detect and correct two common alignment errors. Our two-step technique has proven to be substantially more accurate at alignment than the existing technique that lacked explicit segmentation. It is more important that, for nearly all cases, our new technique results in greater gesture classification accuracy than the existing technique, and performed nearly as well as the benchmark manual speech–sketch alignment.

Reasoning about conditional constraint specification problems and feature models

Abstract: Product configuration is a major industrial application domain for constraint satisfaction techniques. Conditional constraint satisfaction problems (CCSPs) and feature models (FMs) have been developed to represent configuration problems in a natural way. CCSPs are like constraint satisfaction problems (CSPs), but they also include potential variables, which might or might not exist in any given solution, as well as classical variables, which are required to take a value in every solution. CCSPs model, for example, options on a car, for which the style of sunroof (a variable) only makes sense if the car has a sunroof at all. FMs are directed acyclic graphs of features with constraints on edges. FMs model, for example, cell phone features, where utility functions are required, but the particular utility function "games" is optional, but requires Java support. We show that existing techniques from formal methods and answer set programming can be used to naturally model CCSPs and FMs. We demonstrate configurators in both approaches. An advantage of these approaches is that the model builder does not have to reformulate the CCSP or FM into a classic CSP, converting potential variables into classical variables by adding a "does not exist" value and modifying the problem constraints. Our configurators automatically reason about the model itself, enumerating all solutions and discovering several kinds of model flaws.

Product configuration as decision support: The declarative paradigm in practice

Abstract: Product configuration is a key technology, which enables businesses to deliver and deploy individualized products. In many cases, finding the optimal configuration solution for the user is a creative process that requires them to decide trade-offs between conflicting goals (multicriteria optimization problem). These problems are best supported by an interactive dialog that is managed by a dedicated software program (the configurator) that provides decision support. We illustrate this using a real example (configuration of a business software system). This productively used application makes the user aware of which choices are available in a given situation, provides assistance in resolving inconsistent choices and defaults, and generates explanations if desired. One of the key configurator components used to manage this is a truth maintenance system. We describe how this component is used and two novel extensions to it: methods for declarative handling of defaults (of varying strength) and the declarative handling of incompleteness. Finally, we summarize our experiences made during the implementation of this application and the pros and cons of declarative versus procedural approaches.

Design computing and cognition (dcc'10)

Abstract: † Assessing the Impact of Complexity Science in Design † Design Communication † Understanding Functions † Computational Design Synthesis: Knowledge Representation † Conceptual Computational Design Tools: Bridging the Gap Between Abstract Requirements and Concrete Implementation Strategies † Design Creativity † Shape Grammar Implementation: From Theory to Useable Software † Research Methods for Design Cognition

Evaluating an evolutionary method of design style imitation

Abstract: We propose a computational method for producing novel constructs that fall within an existing design or artistic style. The method is based on evolutionary algorithms, and we discuss related knowledge representation issues. We then present an implementation of this method that we used in order to imitate the style of the Dutch painter Mondrian. Finally, we explain and give the results of a cognitive experiment designed to determine the effectiveness of the method, and provide a discussion of these results.

Special Issue: Configuration

Abstract: Configuration can be defined as the composition of a complex product from instances of a set of component types, taking into account restrictions on the compatibility of those component types. For supporting product configuration, different artificial intelligence (AI) approaches are well established as central technologies in industrial configuration systems. However, the wide industrial use of configuration technologies and the increasing size and complexity of configuration problems make the field more challenging than ever. Today the mass customization paradigm has been extended from traditional physical products to the fields of software and service configuration. Configuration systems have evolved into interactive Web-based applications that need to support highly sophisticated knowledge representation and reasoning methods. A wide range of AI techniques are applied in this context: just to mention a few, constraint satisfaction, intelligent user interfaces, preference handling, and explanations. As a successful AI application area, configuration has attracted lasting industrial interest and renewed research, as demonstrated by a series of workshops on configuration that have been arranged in conjunction with leading AI conferences such as IJCAI, ECAI, and AAAI. The goal of this Special Issue on configuration is to demonstrate novel and innovative configuration research as well as new industrial applications of configuration technologies. The contributions of this Special Issue on configuration are a continuation of high-quality papers in previous special issues on configuration published in such journals as IEEE Intelligent Systems (1998), AI EDAM (1998 and 2003), and International Journal of Mass Customization (2010). The seven papers (five fulllength papers and two short papers) were selected from 17 submissions, which corresponds to a full-length paper acceptance rate of 29%. Each paper underwent two to four double-blind reviews by experts in the configuration domain. Papers with a positive reviewer feedback after the first review round were reviewed again to assure that all of the reviewer comments of the first round had been taken into account. The reviews of papers that included acoeditoras an author were managed in a screened manner by uninvolved coeditors or members of the Special Issue program committee. The major topics of the current Special Issue include personalization techniques and algorithms in knowledge-based configuration, different issues of configuration knowledge representation, industrial configuration environments and new application domains, and business-oriented aspects of the application of configuration technologies. “Modeling and Solving Technical Product Configuration Problems” by Andreas Falkner, Alois Haselboeck, Gottfried Schenner, and Herwig Schreiner contains an introduction to the “partner units” problem and provides a discussion of possible alternative knowledge representation approaches (e.g., Unified Modeling Language/Object Constraint Language and Alloy). In addition, the paper contains a discussion of possible approaches to solve the “partner units” problem (from basic backtracking to local search approaches such as “simulated annealing”). The paper is concluded with an in-depth analysis of the applied search algorithms. In their short paper on “Product Configuration as Decision Support: The Declarative Paradigm in Practice” Albert Haag and Steffen Riemann discuss knowledge representation issues in the SAP configuration environment. As an application domain for configuration technologies they introduce the customization of SAP systems. Besides the discussion of the advantages and trade-offs of procedural and declarative knowledge representations, the authors provide an in-depth discussion of the application of assumption-based truth maintenance approaches in their configuration environment. “A Declarative Framework for Work Process Configuration,” written by Wolfgang Mayer, Markus Stumptner, Peter Killisperger, and Georg Grossmann, extends established constraint-based configuration approaches with a constraint representation language for representing specific properties of execution paths in work processes. In this context, a framework for semiautomated process customization is introduced. It integrates the extended constraint approach with a metamodel of work processes. Valid process configurations are then semiautomatically built on the basis of heuristic search. In their short paper on “Reasoning about Conditional Constraint Specification Problems and Feature Models” Raphael Reprint requests to: Alexander Felfernig, Institute for Software Technology, Graz University of Technology, Inffeldgasse 16b, Graz A-8010, Austria. E-mail: alexander.felfernig@ist.tugraz.at Artificial Intelligence for Engineering Design, Analysis and Manufacturing (2011), 25, 113–114. # Cambridge University Press 2011 0890-0604/11 $25.00 doi:10.1017/S0890060410000569

A coupled configurational description of boundary shape based on distance and directionality

Abstract: A configurational method for describing shape is proposed based on two measures that gauge human experiences of moving through space: distance and changes in direction of travel. Boundary shapes from the built environment and nature are studied in a morphospace composed of two axes: one corresponding to each measure, to yield a typological classification of form. It is shown that the covariance between distance and directionality is mediated by the topological structure of embedded main circulation. Three kinds of circulation-elementary, ring, and linear-thus affect three fundamentally different balancing conditions between distance and directionality in boundary shapes. The analysis of large samples of shapes thus far demonstrates a "unique shape" status, where no two different shapes have the same pair of relative distance and directional fragmentation values.