Showing papers in "Computer-aided Design in 2012"
TL;DR: This paper presents an approach to enable the translation of STEP schema and its instances to Ontology Web Language (OWL), which gives a model-which is called OntoSTEP-that can easily be integrated with any OWL ontologies to create a semantically rich model.
Abstract: The representation and management of product lifecycle information is critical to any manufacturing organization. Different modeling languages are used at different lifecycle stages, for example STEP's EXPRESS may be used at a detailed design stage, while UML may be used for initial design stages. It is necessary to consolidate product information created using these different languages to build a coherent knowledge base. In this paper, we present an approach to enable the translation of STEP schema and its instances to Ontology Web Language (OWL). This gives a model-which we call OntoSTEP-that can easily be integrated with any OWL ontologies to create a semantically rich model. As an example, we combine geometry information represented in STEP with non-geometry information, such as function and behavior, represented using the NIST's Core Product Model (CPM). A plug-in for Protege is developed to automate the different steps of the translation. As additional benefits, reasoning, inference procedures, and queries can be performed on enriched legacy CAD models. We describe the rules for the translation from EXPRESS to OWL, and illustrate the benefits of OWL translation with an example. We will also describe how these mapping rules can be implemented through meta-model based transformations, which can be used to map other languages to OWL.
228 citations
TL;DR: DANE illustrates how cognitive studies of design can inform the development of CAD systems for collaborative, conceptual, and creative design, help assess their use in practice, and provide new insights into human interaction with knowledge-based CAD systems.
Abstract: We envision that the next generation of knowledge-based CAD systems will be characterized by four features: they will be based on cognitive accounts of design, and they will support collaborative design, conceptual design, and creative design. In this paper, we first analyze these four dimensions of CAD. We then report on a study in the design, development and deployment of a knowledge-based CAD system for supporting biologically inspired design that illustrates these four characteristics. This system, called DANE for Design by Analogy to Nature Engine, provides access to functional models of biological systems. Initial results from in situ deployment of DANE in a senior-level interdisciplinary class on biologically inspired design indicates its usefulness in helping designers conceptualize design of complex systems, thus promising enough to motivate continued work on knowledge-based CAD for biologically inspired design. More importantly from our perspective, DANE illustrates how cognitive studies of design can inform the development of CAD systems for collaborative, conceptual, and creative design, help assess their use in practice, and provide new insights into human interaction with knowledge-based CAD systems.
204 citations
TL;DR: Compared to other parametric human modeling approaches, this method contributes to the related field by introducing a novel method for correlating body shape and body sizes and by establishing an improved parameter optimization technique for the model generation process.
Abstract: The objective of this study is the development of a novel parametric human body shape modeling framework for integration into various product design applications. Our modeling framework is comprised of three phases of database construction, statistical analysis, and model generation. During the database construction phase, a 3D whole body scan data of 250 subjects are obtained, and their data structures are processed so as to be suitable for statistical analysis. Using those preprocessed scan data, the characteristics of the human body shape variation and their correlations with several items of body sizes are investigated in the statistical analysis phase. The correlations obtained from such analysis allow us to develop an interactive modeling interface, which takes the body sizes as inputs and returns a corresponding body shape model as an output. Using this interface, we develop a parametric human body shape modeling system and generate body shape models based on the input body sizes. In our experiment, our modeler produced reasonable results having not only a high level of accuracy but also fine visual fidelity. Compared to other parametric human modeling approaches, our method contributes to the related field by introducing a novel method for correlating body shape and body sizes and by establishing an improved parameter optimization technique for the model generation process.
134 citations
TL;DR: A new variational method for mesh segmentation by fitting quadric surfaces that integrates feature-based and simplification-based techniques in the segmentation framework, which greatly improve the performance.
Abstract: We present a new variational method for mesh segmentation by fitting quadric surfaces. Each component of the resulting segmentation is represented by a general quadric surface (including plane as a special case). A novel energy function is defined to evaluate the quality of the segmentation, which combines both L^2 and L^2^,^1 metrics from a triangle to a quadric surface. The Lloyd iteration is used to minimize the energy function, which repeatedly interleaves between mesh partition and quadric surface fitting. We also integrate feature-based and simplification-based techniques in the segmentation framework, which greatly improve the performance. The advantages of our algorithm are demonstrated by comparing with the state-of-the-art methods.
115 citations
TL;DR: A product modeling framework and a CAD system for conceptual design of complex products focusing on hierarchical system decomposition and consistency management of design information across different engineering disciplines is proposed.
Abstract: Conceptual design of modern products has become complex due to an increasing number of subsystems and components comprising the system and the multi-disciplinarity of the employed design knowledge. The paper proposes a product modeling framework and a CAD system for conceptual design of complex products focusing on hierarchical system decomposition and consistency management of design information across different engineering disciplines. The framework and CAD system support these tasks with concurrent development of functional and parameter-level product descriptions and comprehensive evaluation of these descriptions from functional, parameter-level, structural, and behavioral aspects. A conceptual design case at a printer manufacturer is demonstrated.
114 citations
TL;DR: The results showed that the largest variations among people were general size, especially for width and depth, and face height, forehead, back of the head, chin and jaw area were also important when describing the 3D shape.
Abstract: Perfect fit for people has always been a target for product design. Designers commonly use traditional anthropometric dimensions for 3D product design thus creating a lot of fitting problems when dealing with the complexities of human body shapes. The development of recent 3D anthropometric survey has created an opportunity for complex shape analysis on human model by collecting 3D scan data. Using 3D point cloud data from the SizeChina survey, a methodology of creating a homologous 3D head and face model was demonstrated in this study. Anatomical and virtual landmarks, and surface modeling algorithm based on point cloud data were applied in building the model. The head and face models for all scans had the same amount of vertices with consistent features. The average Chinese models showed obvious differences between male and female. The variations of head and face shapes were analyzed using Principal Component Analysis and the results showed that the largest variations among people were general size, especially for width and depth. However face height, forehead, back of the head, chin and jaw area were also important when describing the 3D shape. The results from this study may be useful in the design of head and facial products.
89 citations
TL;DR: A knowledge-based framework for the creative conceptual design of multi-disciplinary systems through reusing and synthesizing known principle solutions in various disciplines together for achieving the desired functions is proposed.
Abstract: Designers often have difficulty in fulfilling creative conceptual designs of multi-disciplinary systems due to the lack of sufficient multi-disciplinary knowledge. Therefore, this paper proposes a knowledge-based framework for the creative conceptual design of multi-disciplinary systems through reusing and synthesizing known principle solutions in various disciplines together. It comprises a formal constraints-based approach for representing the desired functions, a domain-independent approach for modeling functional knowledge of known principle solutions, and a heterogeneous-object-state-search-based approach for synthesizing known principle solutions together for achieving the desired functions. A design case illustrates that the proposed framework can successfully achieve creative conceptual design of multi-disciplinary systems. A prototype system, called the Intelligent Creative Conceptual Design Platform, is implemented based on this framework.
85 citations
TL;DR: It is demonstrated, for the first time, that a PSO based optimizer outperforms classical mathematical programming based methods, such as active set and trust region algorithms, in the optimal design of functionally graded materials.
Abstract: A new method for the optimal design of Functionally Graded Materials (FGM) is proposed in this paper. Instead of using the widely used explicit functional models, a feature tree based procedural model is proposed to represent generic material heterogeneities. A procedural model of this sort allows more than one explicit function to be incorporated to describe versatile material gradations and the material composition at a given location is no longer computed by simple evaluation of an analytic function, but obtained by execution of customizable procedures. This enables generic and diverse types of material variations to be represented, and most importantly, by a reasonably small number of design variables. The descriptive flexibility in the material heterogeneity formulation as well as the low dimensionality of the design vectors help facilitate the optimal design of functionally graded materials. Using the nature-inspired Particle Swarm Optimization (PSO) method, functionally graded materials with generic distributions can be efficiently optimized. We demonstrate, for the first time, that a PSO based optimizer outperforms classical mathematical programming based methods, such as active set and trust region algorithms, in the optimal design of functionally graded materials. The underlying reason for this performance boost is also elucidated with the help of benchmarked examples.
85 citations
TL;DR: A new assembly retrieval approach is presented, based on which, users can input flexible queries, either rough or precise, to retrieve efficiently the whole or partial assemblies they want from the product library, which collects different levels of information in assembly models.
Abstract: Nowadays, growing quantities of product models are created in industries. Usually, these models contain abundant design knowledge, either explicit or implicit, in various disciplines. As an approach to taking full advantage of the design knowledge embedded, model reuse plays an increasingly important part in complex product design and innovative design, in which enormous time and cost can be saved. While model retrieval is a natural and promising way to help designers find the right models for quick and accurate reuse, the retrieval technology for assemblies is yet to reach maturity since the previous text-based or low-level content-based assembly retrieval could not fully support the needs of users. In this paper, a new assembly retrieval approach is presented, based on which, users can input flexible queries, either rough or precise, to retrieve efficiently the whole or partial assemblies they want from the product library. First, a multilevel assembly descriptor supporting various searching requirements is elaborated, which collects different levels of information in assembly models. Then, the corresponding matching and similarity assessment methods with well-balanced efficiency and discriminability are given to evaluate the differences between assembly models. Moreover, an indexing mechanism for accelerating assembly retrieval, especially the partial retrieval, is presented to filter the unmatchable models quickly. Finally, an assembly retrieval prototype system is implemented, and the experimental results are analyzed to verify the advantages of the flexible assembly retrieval approach.
81 citations
TL;DR: A flexible shape control technique is provided in this paper for the automatic resizing of apparel products to preserve the shape of user-defined features on the apparel products.
Abstract: We provide a flexible shape control technique in this paper for the automatic resizing of apparel products. The automatic resizing function has become an essential part of the 3D garment CAD systems to generate user customized apparel products for individuals with variant body shapes. The human bodies are usually represented by piecewise linear mesh surfaces with consistent connectivity. The shape of apparel products can then be warped from the space around a human body to the space around another body by computing the new positions of points on apparel products. However, one major limitation of this kind of automatic resizing technique is that the apparel products are always distorted along the shape of the human bodies. This is a required deformation for tight clothes but not an expected result for other types of clothes. To solve this problem, we investigate a method to preserve the shape of user-defined features on the apparel products. As the apparel products are often represented by discrete surfaces with non-manifold entities, the existing mesh processing approaches that preserve the local shape cannot be applied here. A new algorithm consisting of three steps is developed in this paper. First, the apparel product is warped from the reference human body to the space around the target human body. Second, the shape of features is optimized to match their original shape before the warping. Lastly, discrete surfaces of the apparel product are deformed again under an optimization framework to match their original shapes locally while interpolating the shape of features determined in the previous step.
77 citations
TL;DR: This paper addresses the role of multiple shape representations with varying uncertainty levels during 3D conceptual sketching, along with methods to transform between those representations, and introduces techniques that can be incorporated in future computer-aided conceptual design systems.
Abstract: This paper enables the rapid creation and modification of freeform surfaces inside an augmented reality environment, and focuses on methods for enabling increased flexibility during exploratory, conceptual industrial product design through three-dimensional (3D) sketch-based user input. Specifically, we address the role of multiple shape representations with varying uncertainty levels during 3D conceptual sketching, along with methods to transform between those representations. The main contributions of this work are: (1) the formulation of virtual shape data in multiple, concurrent representations (points and surfaces), and a regression method to transition fluidly back and forth between these representations during design, (2) methods for deforming and exploring the product shape using these multiple representations, and (3) representations of these forms such that designers can explore conceptual designs without the need for detailed surface operations such as trimming or continuity enforcement. Through incorporating these contributions, we introduce techniques that can be incorporated in future computer-aided conceptual design systems. These contributions are demonstrated for freeform surface design, with examples of computer mouse and car seat exterior surfaces.
TL;DR: This paper proposes a mathematical formulation of tolerance analysis which integrates the notion of quantifier, which provides a univocal expression of the condition corresponding to a geometrical product requirement.
Abstract: Tolerancing decisions can profoundly impact the quality and cost of the mechanism To evaluate the impact of tolerance on mechanism quality, designers need to simulate the influences of tolerances with respect to the functional requirements This paper proposes a mathematical formulation of tolerance analysis which integrates the notion of quantifier: ''For allacceptable deviations (deviations which are inside tolerances),there existsa gap configurationsuch asthe assembly requirements and the behavior constraints are verified'' & ''For allacceptable deviations (deviations which are inside tolerances), andfor alladmissible gap configurations, the assembly and functional requirements and the behavior constraints are verified'' The quantifiers provide a univocal expression of the condition corresponding to a geometrical product requirement This opens a wide area for research in tolerance analysis To solve the mechanical problem, an approach based on optimization is proposed Monte Carlo simulation is implemented for the statistical analysis The proposed approach is tested on an over-constrained mechanism
TL;DR: The inheritance mechanisms are explored to ensure the feasibility of information transferring and conversion between different design phases in the top-down assembly design process to better exhibit the recursive-execution and structure-evolvement characteristics of product design.
Abstract: To enable next generation CAD tools to effectively support top-down design of products, a top-down assembly design process is refined from the traditional product design process to better exhibit the recursive-execution and structure-evolvement characteristics of product design. Based on the top-down assembly design process, a multi-level assembly model is put forward to capture the abstract information, skeleton information and detailed information involved. The multi-level assembly model is a meta-level implementation and is easy to be extended. Moreover, the inheritance mechanisms are explored to ensure the feasibility of information transferring and conversion between different design phases in the top-down assembly design process. A top-down assembly design sample is analyzed at length to show the application effects of the multi-level assembly model and the relevant inheritance mechanisms. In addition, a practical topic about the model adaptation of existing CAD systems is also discussed for a broader application of the top-down assembly design. Finally, the conclusion of the work and the future directions for further exploration are given.
TL;DR: A novel computer aided design (CAD) solution for virtual try-on, fitting evaluation and style editing is proposed to speed up the clothing design process and the standard rules regulating pattern editing in the fashion industry can be incorporated in the system.
Abstract: The traditional apparel product development process is a typical iterative 'optimization' process that involves trial-and-error. In order to confirm the design and achieve a satisfactory fit, a number of repeated cycles of sample preparation, trial fitting and pattern alteration must be conducted. The process itself is time-consuming, costly, and dependent on the designer's skills and experience. In this paper, a novel computer aided design (CAD) solution for virtual try-on, fitting evaluation and style editing is proposed to speed up the clothing design process. A series of new techniques from cross parameterization, geometrical and physical integrated deformation, to novel editing methods are proposed. First, a cross parameterization technique is employed to map clothing pattern pieces on a model surface. The pattern can be precisely positioned to form the initial shape with low distortion. Next, a new deformation method called hybrid pop-up is proposed to approximate the virtual try-on shape. This method is an integration of geometrical reconstruction and physical based simulation. In addition, user interactive operations are introduced for style editing and pattern alteration in both 2D and 3D manners. The standard rules regulating pattern editing in the fashion industry can be incorporated in the system, so that the resulting clothing patterns are suitable for everyday production.
TL;DR: Experiments and algorithms that use the BCI to distinguish between primitive shapes that are imagined by a user are described, showing that theBCI holds promise in creating geometric shapes in CAD systems and could be used as a novel means of user interaction.
Abstract: Brain-computer interfaces (BCIs) are recent developments in alternative technologies of user interaction. The purpose of this paper is to explore the potential of BCIs as user interfaces for CAD systems. The paper describes experiments and algorithms that use the BCI to distinguish between primitive shapes that are imagined by a user. Users wear an electroencephalogram (EEG) headset and imagine the shape of a cube, sphere, cylinder, pyramid or a cone. The EEG headset collects brain activity from 14 locations on the scalp. The data is analyzed with independent component analysis (ICA) and the Hilbert-Huang Transform (HHT). The features of interest are the marginal spectra of different frequency bands (theta, alpha, beta and gamma bands) calculated from the Hilbert spectrum of each independent component. The Mann-Whitney U-test is then applied to rank the EEG electrode channels by relevance in five pair-wise classifications. The features from the highest ranking independent components form the final feature vector which is then used to train a linear discriminant classifier. Results show that this classifier can discriminate between the five basic primitive objects with an average accuracy of about 44.6% (compared to naive classification rate of 20%) over ten subjects (accuracy range of 36%-54%). The accuracy classification changes to 39.9% when both visual and verbal cues are used. The repeatability of the feature extraction and classification was checked by conducting the experiment on 10 different days with the same participants. This shows that the BCI holds promise in creating geometric shapes in CAD systems and could be used as a novel means of user interaction.
TL;DR: This paper integrates ontology technology into a CBR system by constructing domain ontology as case-base with a new method, in which two means of acquisition are combined and the proposed approach outperforms existing CBR systems.
Abstract: Case-based reasoning (CBR) often shows significant promise for improving the effectiveness of design support in mould design, which is a domain strong in practice but poor in theory. However, existing CBR systems lack semantic understanding, which is important for intelligent knowledge retrieval in design support system. This hinders the application of CBR in injection mould design. In order to develop an intelligent CBR system and meet the need of design support for injection mould design, this paper integrates ontology technology into a CBR system by constructing domain ontology as case-base with a new method, in which two means of acquisition are combined, one is acquiring ontology from existing ontologies, the other from established engineering knowledge resources, and proposing a new semantic retrieval method as the first grade case retrieval. Numerical measurement is also employed as the second grade case retrieval, which adopts various methods to calculate different types of attribute values. A case is executed to illustrate the use of proposed CBR system, then a lot of experiments are organized to evaluate its performance and the result shows that the proposed approach outperforms existing CBR systems.
TL;DR: The parametric design concept is applied onto the stent design and integrated with the developed FEA/CFD models to evaluate several key clinically-relevant functional attributes recommended by the FDA, which have yet to be systematically investigated.
Abstract: Atherosclerosis, a condition related to cholesterol build-up and thickening of the inner wall of the artery, narrows or occludes the artery lumen. A stent is a miniature medical device deployed in a stenotic artery to restore the blood flow. In this paper, we propose to apply the parametric design concept onto the stent design and integrate it with the developed FEA/CFD models to evaluate several key clinically-relevant functional attributes recommended by the FDA. These key clinical attributes include stresses/strains, fatigue resistance, radial strength, expansion recoil, and wall shear stresses, which have yet to be systematically investigated. Finite element models were developed to predict the mechanical integrity of a balloon-expandable stent at various stages such as crimping onto a balloon catheter, stent expansion, radial strength to resist blood vessels from collapsing, and service life in the human body when subjected to pulsatile blood pressure. Computational fluid dynamics models were developed to predict the wall shear stress distribution in stented arteries. A stent parametric analysis was conducted using the integrated computational schemes to systematically evaluate the effects of varying stent design parameters on key clinically-relevant functional attributes. Each stent design parameter was varied in its dimension from -30% to +30% (compared to the standard case) for sensitivity studies in attempts to find the most dominant design parameter for each key clinical attribute. The developed design/analytical schemes allow us to gain deeper insight into the fundamental stent issues and evaluate the mechanical/hemodynamic behavior of various stent designs.
TL;DR: Two methods to accelerate the iterative geometric interpolation algorithm, as well as a method to impose geometric constraints, such as reflectional symmetry, on the iteration process, and a novel fairing method for non-uniform complex data points are introduced.
Abstract: Recently, the use of B-spline curves/surfaces to fit point clouds by iteratively repositioning the B-spline's control points on the basis of geometrical rules has gained in popularity because of its simplicity, scalability, and generality. We distinguish between two types of fitting, interpolation and approximation. Interpolation generates a B-spline surface that passes through the data points, whereas approximation generates a B-spline surface that passes near the data points, minimizing the deviation of the surface from the data points. For surface interpolation, the data points are assumed to be in grids, whereas for surface approximation the data points are assumed to be randomly distributed. In this paper, an iterative geometric interpolation method, as well as an approximation method, which is based on the framework of the iterative geometric interpolation algorithm, is discussed. These two iterative methods are compared with standard fitting methods using some complex examples, and the advantages and shortcomings of our algorithms are discussed. Furthermore, we introduce two methods to accelerate the iterative geometric interpolation algorithm, as well as a method to impose geometric constraints, such as reflectional symmetry, on the iterative geometric interpolation process, and a novel fairing method for non-uniform complex data points. Complex examples are provided to demonstrate the effectiveness of the proposed algorithms.
TL;DR: This work proposes a NURBS interpolator that is able to satisfy all the manufacturing technology requirements and was able to respect, thanks to its bounded computational complexity, the position control real-time constraints.
Abstract: Advances in manufacturing technologies and in machine tools allow for unprecedented quality and efficiency in production lines, but also ask for new and increasing requirements on the motion planning and control systems. The increase of CPU processing power has permitted, in traditional CNC systems, the introduction of NURBS interpolation capabilities, thus determining a further increase in machining quality and efficiency. This has posed new and still unsolved issues, such as the need to satisfy multiple opposite constraints like limiting chord error, acceleration and jerk and offering real-time guarantees. In addition, the ability of privileging the production throughput by relaxing one or more of the previous constraints in a simple way, has emerged as another requirement of modern manufacturing plants. Nevertheless, none of the existing NURBS interpolators have these characteristics. In this work, we propose a NURBS interpolator that is able to satisfy all the manufacturing technology requirements and is able to respect, thanks to its bounded computational complexity, the position control real-time constraints. Such an interpolator is easily reconfigurable, i.e., it can relax some of the constraints while maintaining performances better than previously proposed solutions, and can be adapted in order to include constraints that were not originally considered. Performances of the proposed algorithm have been evaluated both by simulations and by real milling experiments.
TL;DR: This paper obtains the parametric representation for a surface pencil whose members have the same curve as a given asymptotic curve using the Frenet frame of the given asynchotic curve.
Abstract: In this paper, we study the problem of finding a surface pencil from a given spatial asymptotic curve. We obtain the parametric representation for a surface pencil whose members have the same curve as a given asymptotic curve. Using the Frenet frame of the given asymptotic curve, we present the surface as a linear combination of this frame and analyse the necessary and sufficient condition for that curve to be asymptotic. We illustrate this method by presenting some examples.
TL;DR: A novel method that combines text mining, natural language processing, creation of knowledge-transfer metrics, and application of machine learning approaches is presented and implemented for classifying patents according to level of invention (LOI).
Abstract: Patents provide a wealth of information about design concepts, their physical realization, and their relationship to prior designs in the form of citations. Patents can provide useful input for several goals of next-generation computer-aided design (CAD) systems, yet more efficient tools are needed to facilitate patent search and ranking. In this paper, a novel framework is presented and implemented for classifying patents according to level of invention (LOI) as defined in the theory of inventive problem solving (TRIZ). Level of invention characterizes the creativity of a design concept based on the resolution of a design conflict and the disciplines used in resolving the conflict. The assessment of LOI for a series of patents provides a useful input for screening and ranking patents in databases to identify high-impact patents. However, the manual effort required for assigning LOI to each patent is laborious and time-consuming. In this paper, a novel method that combines text mining, natural language processing, creation of knowledge-transfer metrics, and application of machine learning approaches is presented and implemented for classifying patents according to LOI. Two case studies are presented in which LOI data is compiled for patents: dynamic magnetic information storage or retrieval using Giant Magnetoresistive (GMR) or Colossal Magnetoresistive (CMR) sensors formed of multiple thin films (USPC 360/324) and arbitration for access to a channel (USPC 370/462). The peak performance in 5-fold stratified cross-validation was found to be 73.38% in the first case study and 77.12% for the second.
TL;DR: A general, robust approach for mesh denoising by using a combination of bilateral filtering, feature recognition, anisotropic neighborhood searching, and surface fitting and projection techniques is proposed.
Abstract: Mesh denoising is crucial for improving noisy meshes acquired from scanning devices and digitization processes. This paper proposes a general, robust approach for mesh denoising by using a combination of bilateral filtering, feature recognition, anisotropic neighborhood searching, and surface fitting and projection techniques. Motivated by the bilateral filtering from image processing applications, we develop a new bilateral filter operating on the normal vector fields of the mesh. Then, we detect mesh features and classify mesh vertices into non-feature vertices and feature vertices. The corresponding anisotropic neighborhoods for each vertex are searched by constructing a weighted dual graph, over which biquadratic Bezier surface patches are fitted and projected. The projection points are averaged to update each vertex of the mesh. The steps above are repeated iteratively until convergence, i.e., the Hausdorff distance between two sequential denoised meshes is less than a pre-defined threshold. A number of examples presented in the paper demonstrate that our method generally yields visually and numerically better denoising results, compared with the state-of-the-art methods.
TL;DR: In this paper, an original model and a dialogue-based software application have been developed by integrating the logic of ARIZ (Algorithm for the Inventive Problem Solving) with some OTSM-TRIZ (General Theory of Powerful Thinking) models in order to guide a user also with no TRIZ education to the analysis of inventive problems.
Abstract: The paper presents the research activity developed by the authors in the field of computer-aided inventive problem solving: an original model and a dialogue-based software application have been developed by integrating the logic of ARIZ (Algorithm for the Inventive Problem Solving) with some OTSM-TRIZ (General Theory of Powerful Thinking) models in order to guide a user also with no TRIZ education to the analysis of inventive problems. The paper demonstrates that through a dialogue-based interaction it is possible to guide the user towards a proper formulation of the problem statement, which is an essential step of any conceptual design activity. The proposed software system, although still at a prototype stage, has been tested with students at Politecnico di Milano and at the University of Florence. The paper details the structure of the algorithm and the results of the first validation activity; then, it discusses about the possibility to integrate the proposed approach into a new generation of CAD systems.
TL;DR: A new approach to shape representation called a composite adaptively sampled distance field (composite ADF) is described and its application to NC milling simulation and an implementation of 3 and 5-axis milling Simulation is described.
Abstract: We describe a new approach to shape representation called a composite adaptively sampled distance field (composite ADF) and describe its application to NC milling simulation. In a composite ADF each shape is represented by an analytic or procedural signed Euclidean distance field and the milled workpiece is given as the Boolean difference between distance fields representing the original workpiece volume and distance fields representing the volumes of the milling tool swept along the prescribed milling path. The computation of distance field of the swept volume of a milling tool is handled by an inverted trajectory approach where the problem is solved in tool coordinate frame instead of a world coordinate frame. An octree bounding volume hierarchy is used to sample the distance functions and provides spatial localization of geometric operations thereby dramatically increasing the speed of the system. The new method enables very fast simulation, especially of free-form surfaces, with accuracy better than 1 micron, and low memory requirements. We describe an implementation of 3 and 5-axis milling simulation.
TL;DR: This paper focuses on algorithm design to discover DR from design documents according to the ISAL modeling, and improves the manifold-ranking algorithm to extract issue-bearing sentences and solution-reason bearing sentences for the solution layer.
Abstract: Collecting design rationale (DR) and making it available in a well-organized manner will better support product design, innovation and decision-making. Many DR systems have been developed to capture DR since the 1970s. However, the DR capture process is heavily human involved. In addition, with the increasing amount of DR available in archived design documents, it has become an acute problem to research a new computational approach that is able to capture DR from free textual contents effectively. In our previous study, we have proposed an ISAL (issue, solution and artifact layer) model for DR representation. In this paper, we focus on algorithm design to discover DR from design documents according to the ISAL modeling. For the issue layer of the ISAL model, we define a semantic sentence graph to model sentence relationships through language patterns. Based on this graph, we improve the manifold-ranking algorithm to extract issue-bearing sentences. To discover solution-reason bearing sentences for the solution layer, we propose building up two sentence graphs based on candidate solution-bearing sentences and reason-bearing sentences respectively, and propagating information between them. For artifact information extraction, we propose two term relations, i.e. positional term relation and mutual term relation. Using these relations, we extend our document profile model to score the candidate terms. The performance and scalability of the algorithms proposed are tested using patents as research data joined with an example of prior art search to illustrate its application prospects.
TL;DR: The result of the prototype test demonstrates that the proposed model can enable designers from different disciplines participating in an AEC project to better understand the dynamic process of design and achieve a high level of shared understanding.
Abstract: Fostering collaboration in the AEC (Architecture/Engineering/Construction) field is difficult, due to the differing educational and disciplinary backgrounds of the participants. Current approaches to managing such collaboration in the AEC industry often fail to overcome the disciplinary differences among the participants, resulting in cost overruns, missed schedules, and diminished satisfaction of the clients or society. Their failure is due to the lack of understanding of the nature of multi-disciplinary design and the lack of tools that can support them. The primary objective of this research is to establish a suitable model for machine-mediated collaboration. In contrast to the monolithic model, which is insensitive to changes, we propose to develop a distributed and flexible model, where each domain of expertise retains its own data in the form most appropriate for its needs, and where ontology-based, intelligent filters translate neutral design data into domain-specific ones. The filtered data appear semantically-rich to the participant, even when it was generated by another participant. To verify the feasibility of the proposed filter-based communication model, we developed and tested a prototype. The result of the prototype test demonstrates that the proposed model can enable designers from different disciplines participating in an AEC project to better understand the dynamic process of design and achieve a high level of shared understanding.
TL;DR: This paper proposes a scheme that detects and locates malicious attacks with high accuracy while ensuring exact recovery of the original content and discusses selecting appropriate embedding parameters to achieve good performance in terms of the tamper localization ability, invisibility, authentication power and security.
Abstract: A 2-D vector map is very important data in the surveying and mapping fields. It is considered to be content for which verification of integrity and authenticity are urgently required. Several reversible fragile watermarking schemes based on lossless compression presented in the literature guarantee neither exact recovery of the original content nor good tamper localization performance. Using a novel marking technique and a reversible data-hiding method, we propose a scheme that detects and locates malicious attacks with high accuracy while ensuring exact recovery of the original content. In particular, we propose calculating watermarks for each spatial feature group, embedding the watermark in a reversible manner and marking the original location of each feature using interpolated vertices. While the mark of each feature ensures superior accuracy of tamper localization, the reversible data-hiding method provides exact recovery of the original content. Moreover, this paper discusses selecting appropriate embedding parameters to achieve good performance in terms of the tamper localization ability, invisibility, authentication power and security. Experimental results show that the proposed scheme could detect and locate malicious attacks such as vertex/feature modification, vertex addition/deletion, and feature addition/deletion.
TL;DR: A software architecture that operates on port information and controls the status of subsystem interfaces during collaboration is described and a piece of software is implemented based on the proposed architecture and its functionality is demonstrated by two examples.
Abstract: Interfaces between subsystems in collaborative product development projects are presently defined by interface control documents. This paper presents a computer aided methodology for defining and controlling subsystem interfaces. Interfaces are considered as interconnections between subsystem ports. Ports are specified by using an ontology that ensures consistency of interface definitions among different design teams. Every port that is based on the ontology is eventually defined by a set of attributes that are derived from its form and function. Interfaces between ports are formed when ports are mated. The essence of port mating is described by logical information that is expressed in two forms. First, a set of requirements are defined for an individual port to ensure that it functions properly. Second, connectivity rules are expressed between ports to guarantee that they integrate correctly. A software architecture that operates on port information and controls the status of subsystem interfaces during collaboration is described. A piece of software is implemented based on the proposed architecture and its functionality is demonstrated by two examples. The examples show how the software can be used to replace interface control documents and support collaboration. The software allows designers to load subsystem descriptions from a shared repository and connect them together by defining connectivity rules. The software reports errors to designers when port requirements or connectivity rules are violated.
TL;DR: This special issue aims to explore new ideas, theories, methodologies, concepts, functionalities, forms of interaction, technologies and implementations that offer themselves to more efficient systems and applications that will be used by designers and engineers around and after 2020.
Abstract: Since the 1960’s, computers have been playing more and more important roles in engineering practices. The evolution of Computer-Aided Design and Engineering (CAD/E) systems has been driven by both the needs for efficient design processes and high quality representation of products, and the advancement of computing technologies andmethodologies related to design practices. The computing (software) technologies that have greatly impacted on CAD/E systems include geometric modeling, finite element analysis, manufacturing process planning, human factor assessment and optimization algorithms, data base technologies, artificial intelligence, web search technologies, as well as networking and communication technologies. The paradigm behind current CAD/E systems can be characterized by the following features: (i) artifact geometry, structure and process modeling, (ii) displaysbased graphical visualization, (iii) numeric data-based behavioral analysis and simulation, (iv) network-hosted remote collaboration, (v) data base-level functional integration, and (vi) product/process life cycle data management. The market of commercial CAD/E systems is dominated by a number of large software developers who intend to offer complete solutions for the industry. Though academic research is still very active in the field of CAD/E systems, there are indications that the conventional system development resources will sooner and later become exhausted. A new paradigmmight be necessary to provide additional support for the industry, to cope with the complexity of products, processes, and data/knowledge, and to open up new opportunities for researchers, innovators, systemdevelopers, system integrators, and end users. Many recent technological developments, for instance, smart and ubiquitous technologies, cloud computing, semantic web, cyber-physical systems, molecular computing, social networking and brain interfacing, are stimulating the discussions and the research towards a new paradigm. This is the first of a series of special issues targeting the functionality, implementation, integration and application issues, approaches and solutions of next generation of CAD/E systems that will be used by designers and engineers around and after 2020. Special issues on Ubiquitous Computing-Based Design Tools and Systems and Application of Brain–Computer Interfaces in CAD/E Systems are already in development by other guest editors and authors. The objective is to explore new ideas, theories, methodologies, concepts, functionalities, forms of interaction, technologies and implementations that offer themselves to more efficient systems and applications. It is expected that novel information and knowledge mining technologies, mobile communication and ad hoc networking, semantic network technologies, air borne visualization technologies, smart reasoning and agent based computing, ubiquitous sensing and computing technologies, knowledge ontologies, natural interaction techniques will have a say in the formation of the paradigm of next generation CAD/E systems and environments. The objective of this special issue is to provide an overview and to investigate the fundamental theories and techniques that may underlie the new paradigm. One major criterion that we applied at selecting the published papers was if they addressed one or more fundamental issues that might have a significant impact on future CAD/E systems. Based on the recommendation and review comments of the invited peer reviewers, out of twenty-one submissions, ten papers have been selected for publication in this special issue. Most of the submitted papers have gone through three rounds of review. They address issues such as understanding, analysis, synthesis, representation, search and communication in computer aided design and engineering. The papers selected for this special issue can roughly be divided into three categories. The first category includes papers that concentrate on the understanding of design problems and design knowledge (including meaning based information search). The papers belonging to the second category deal with various different aspects of creative design synthesis, while those belonging to the third category address design expression and representation. They indicate a shift from product orientation to designer and environment orientation. Obviously, the contributed papers could cover only a part of this very complex and challenging problem, and raise many more fundamental questions than they could answer. In the first paper, entitled ‘‘Cognitive, collaborative, conceptual and creative — Four characteristics of the next generation of knowledge-based CAD systems: A study in biologically inspired design’’, Goel et al. proposed four characteristics (referred to as four C’s) for the next generation knowledge-based CAD systems. These systems are conceived to be supported by CAD technologies other than computational geometry and computer graphics. They argued that the next generation knowledge-based CAD systems will be (i) cognitive, (ii) collaborative, (iii) conceptual, and (iv) creative. The first C refers to a specific methodology for developing CAD systems, namely, grounding the design, development and deployment of CAD systems in cognitive studies; whereas the other three C’s define the characteristics of design that CAD systems may support. The second C indicates that design is collaborative in at least four dimensions: (i) time; (ii) space; (iii) discipline; and (iv) culture. Communication between systems, between system and human, and between humans is the core for the collaborative process. The third C refers to conceptual design, which mainly focuses on the understanding of the design problem and the synthesizing of design information into solution concepts. The fourth C represents creativity, and indicates that the next generation of CAD systems will support design creativity and creative designs. Based on this framework and by using the SBF (Structure–Behavior–Function) model, the authors introduced in
TL;DR: The model and algorithm for simultaneous optimization of the tool path and shape for five-axis flank milling, representing the swept envelope of a generic rotary cutter as a sphere-swept surface, is developed.
Abstract: By representing the swept envelope of a generic rotary cutter as a sphere-swept surface, our previous work on distance function based tool path optimization is extended to develop the model and algorithm for simultaneous optimization of the tool path and shape for five-axis flank milling. If the tool path is fixed, a novel tool shape optimization method is obtained. If the tool shape is fixed, a tool path optimization method applicable to any rotary cutter is obtained. The approach applies to non-ruled surfaces, and also finds applications in cutter dimension optimization and flank millable surface design. Numerical examples are given to confirm its validity.