Topology and detail geometry optimization for beam structures using homotopy modeling

This paper describes a novel design concept and an algorithm for topology and detail geometry design of a beam structure. Topology, layout, cross-sectional shape and size of each element are treated as a design variable. Homotopy theory is used to classify a topological type of a beam structure. In the design concept, not topology itself of a structure but a detail geometry design space defined by topology is transformed. By introducing the novel concept of an algebraic topology expression and the topology metamorphosis algorithm, active topology transformation becomes possible. A numerical example of topology, layout and cross-sectional optimization of reinforcement for a beam structure is illustrated.     

Four-schema approach: An extended model for database architecture

This paper presents an integrative approach for database design. A four-schema architecture, extending the work of the ANSI/X3/SPARC Committee, is proposed as an overall design framework. The concept of the conceptual schema is analyzed, and its two rather independent components are separated. A database design project is briefly discussed as an example of the proposed four-schema approach.     

基于概念格外延信息量的属性约简算法

概念格是知识处理与分析的一个有力的工具,在知识约简和数据挖掘方面有着重要的利用。首先给出了概念格外延信息量的概念,在此基础上研究了合理刻画属性重要性的指标,并给出了概念格核心属性的判定定理,然后以这些指标作为启发式信息设计了一种新颖的概念格启发式属性约简算法,最后通过实例表明了该约简算法的可行性与有效性。     

An ideation method for generating new product ideas using TRIZ,concept mapping,and fuzzy linguistic evaluation techniques

The quality of initial ideas is considered a critical determinant for successful new product development (NPD). This study presents an ideation method for generating new product ideas. The aims of the proposed method are (1) to clarify and identify potential problems involved in the knowledge domain of the product design through the Su-field enhanced concept mapping diagram; (2) to abstract inventive problems and generate novel product ideas by means of the theory of inventive problem solving (TRIZ) methodology; and, (3) to develop an effective decision aiding method for evaluating alternative ideas and determining promising product ideas using fuzzy linguistic evaluation techniques. The applicability of the ideation method is demonstrated through a case study of an air purifier design. The theoretical and practical implications of the ideation method are also discussed.     

PDCS—a product definition and customisation system for product concept development

In recent years, owing to the rapid changing customer needs and much shorter product life cycle than ever before, employing more efficient and flexible approaches for product concept development has become an imperative for a successful product. This work aims at establishing a novel product definition and customisation system (PDCS) for organisations to meet this demand in today's competitive and globalised business climate. A prototype PDCS is proposed, from a design knowledge-handling viewpoint, in this paper. It comprises two phases, namely, product definition using the laddering technique and a novel design knowledge hierarchy (DKH), and product customisation using an integrated methodology of conjoint analysis (CA) and Kohonen association (KA) techniques. Basically, this system is a method of making design decisions via customer involvement, i.e. a strategy for transferring customer preference into a specific product concept. A case study on wood golf club design has been used to illustrate and validate the PDCS. The details of the validation are discussed.     

概念格属性约简的启发式算法

概念格是知识处理与分析的一个有力的工具,在知识约简和数据挖掘方面有着重要的应用。该文首先从概念外延的角度研究了合理刻画属性重要性的指标,并给出了概念格属性约简的判定定理,然后以这些指标作为启发式信息设计了一种新颖的概念格启发式属性约简算法,最后通过实例表明了该约简算法的可行性与有效性。     

Nonlinear 3D path following control of a fixed-wing aircraft based on acceleration control

This paper focuses on the design of a novel path following control concept for fixed-wing aircraft, which systematically incorporates the nonlinearities of the flight dynamics. By introducing an acceleration based inner loop control, feedforward acceleration demands of nonlinear 3D paths can be directly taken into account. Furthermore, the nonlinear effects of airspeed, orientation, and gravity are considered separately by implementing a cascaded design and feedback linearization. As a result, robust performance of the path following control is achieved even for wind speeds in the order of the aircraft’s airspeed and path accelerations significantly higher than the gravitational acceleration. By further including direct lift control, a high-bandwidth vertical acceleration control is developed. Results of flight experiments show that the designed control concept is particularly beneficial in terms of the tracking performance for 3D paths, the incorporation of input constraints, the robustness against wind and turbulence effects, and the ease of implementation as well as the low computational complexity.     

协同设计中基于状态图的工作流表示模型*

着重讨论了CAD协同设计工作流管理中的工作流表示模型,提出了运用状态图的形式来表示工作流的模型,并详细描述了其定义、特性、建模方法及特性分析,并将该思想应用于建筑协同设计的工作流管理中。     

Microcontroller-operated anthropomorphic manipulator with haptic feedback

This article presents the design of a cluster-distributed computing system to operate and control an anthropomorphic manipulator with haptic feedback. The system hardware consists of four major building blocks, anthropomorphic manipulator, haptic sensor glove, real-time microcontroller-based cluster distributed computing (CDC) network, and closed-loop controller. The system software architecture consists of three key operation modules, namely, the sensor glove, anthropomorphic manipulator and communication module. It is designed based on a shared file system concept which forms the foundation of the CDC protocol. The key advantages of this system are its novel structure and its comparatively low cost using microcontroller-based distributed cluster networks which allow large-scale expansion/integration.     

ActiveX控件容器在可视化编程系统中的实现

ActiveX控件容器能使可视化编程系统的扩展性得到增强.本文详细论讨了在编程系统中构建ActiveX控件容器的设计思路及其具体实现方法,该技术明显提高了"VXI总线测试软件平台"的通用性.     

Fault detection and identification—A filter investigation

This paper develops a new active fault‐tolerant control system based on the concept of analytical redundancy. The novel design presented here consists of an observation filter–based fault detection and identification system integrated with a nonlinear model predictive controller. A number of observation filters are designed, integrated with the nonlinear controller, and tested before reaching the final design, which comprises an unscented Kalman filter for fault detection and identification together with a nonlinear model predictive controller to form an active fault‐tolerant control system.     

Implications of an ethic of privacy for human-centred systems engineering

Privacy remains an intractable ethical issue for the information society, and one that is exacerbated by modern applications of artificial intelligence. Given its complicity, there is a moral obligation to redress privacy issues in systems engineering practice itself. This paper investigates the role the concept of privacy plays in contemporary systems engineering practice. Ontologically a nominalist human concept, privacy is considered from an appropriate engineering perspective: human-centred design. Two human-centred design standards are selected as exemplars of best practice, and are analysed using an existing multi-dimensional privacy model. The findings indicate that the human-centred standards are currently inadequate in dealing with privacy issues. Some implications for future practice are subsequently highlighted.     

Human-centric design personalization of 3D glasses frame in markerless augmented reality

This paper presents a virtual try-on system based on augmented reality for design personalization of facial accessory products. The system offers several novel functions that support real-time evaluation and modification of eyeglasses frame. 3D glasses model is embedded within video stream of the person who is wearing the glasses. Machine learning algorithms are developed for instantaneous tracking of facial features without use of markers. The tracking result enables continuously positioning of the glasses model on the user’s face while it is moving during the try-on process. In addition to color and texture, the user can instantly modify the glasses shape through simple semantic parameters. These functions not only facilitate evaluating products highly interactive with human users, but also engage them in the design process. This work has thus implemented the concept of human-centric design personalization.     

Alias-free voxelization of geometric objects

Introduces a new concept for alias-free voxelization of geometric objects based on a voxelization model (V-model). The V-model of an object is its representation in 3D continuous space by a trivariate density function. This function is sampled during the voxelization and the resulting values are stored in a volume buffer. This concept enables us to study general issues of sampling and rendering separately from object-specific design issues. It provides us with a possibility to design such V-models, which are correct from the point of view of both the sampling and rendering, thus leading to both alias-free volumetric representation and alias-free rendered images. We performed numerous experiments with different combinations of V-models and reconstruction techniques. We have shown that the V-model with a Gaussian surface density profile combined with tricubic interpolation and Gabor derivative reconstruction outperforms the previously published technique with a linear density profile. This enables higher fidelity of images rendered from volume data due to increased sharpness of edges and thinner surface patches     

三维服装CAD中几何约束表达及其求解技术研究

从人体及服装的特点出发,提出三维服装几何元素的概念．采用样条曲线作为基本几何元素,归纳出服装的三种约束关系,即共点、对称和自对称关系;成为约束关系形成的基础．以三种约束关系为基础,建立了面向服装的几何约束图,有效地表达了三维服装几何元素及其相互关系;实现了一种基于约束图的约束求解方法。从而完成了构造服装及对服装的交互参数化修改,文中给出了应用实例,并将参数化方法向高层次图素如样条曲线、曲面作了推广,成功地应用于以样条曲线为几何元素的参数化服装CAD系统中,运行效果良好。     

Output Feedback Regulation of Stochastic Nonlinear Systems With Stochastic iISS Inverse Dynamics

This paper develops a unifying framework for output feedback regulation of stochastic nonlinear systems with more general stochastic inverse dynamics. The contributions of this work are characterized by the following novel features: 1) Motivated by the concept of integral input-to-state stability (iISS) in deterministic systems and stochastic input-to-state stability (SISS) using Lyapunov function in stochastic systems, a concept of stochastic integral input-to-state stability (SiISS) using Lyapunov function is first introduced, two important properties of SiISS are obtained: (i) SiISS is strictly weaker than SISS using Lyapunov function; (ii) SiISS is stronger than the minimum-phase property. However, only under the minimum-phase assumption, there is no dynamic output feedback control law for global stabilization in probability. 2) Almost sure boundedness, a reasonable and stronger concept than boundedness in probability, is introduced. The purpose of introducing the concept is to prove the boundedness and convergence of some signals in the closed-loop control system. 3) Some important mathematical tools which play an essential role in the boundedness and convergence analysis of the closed-loop system are established. 4) A unifying framework is proposed to design a dynamic output feedback control law, which drives the states to the origin almost surely while maintaining all the closed-loop signals bounded almost surely.      

Polycube splines

This paper proposes a new concept of polycube splines and develops novel modeling techniques for using the polycube splines in solid modeling and shape computing. Polycube splines are essentially a novel variant of manifold splines which are built upon the polycube map, serving as its parametric domain. Our rationale for defining spline surfaces over polycubes is that polycubes have rectangular structures everywhere over their domains, except a very small number of corner points. The boundary of polycubes can be naturally decomposed into a set of regular structures, which facilitate tensor-product surface definition, GPU-centric geometric computing, and image-based geometric processing. We develop algorithms to construct polycube maps, and show that the introduced polycube map naturally induces the affine structure with a finite number of extraordinary points. Besides its intrinsic rectangular structure, the polycube map may approximate any original scanned data-set with a very low geometric distortion, so our method for building polycube splines is both natural and necessary, as its parametric domain can mimic the geometry of modeled objects in a topologically correct and geometrically meaningful manner. We design a new data structure that facilitates the intuitive and rapid construction of polycube splines in this paper. We demonstrate the polycube splines with applications in surface reconstruction and shape computing.     

Knowledge representation framework for interactive capture and management of reflection process in product concepts development

A design process can be characterized by reflection-in-action; that is, the process consists of a series of problem solving activities and each is embodied with a problem and a solution. In this process, a designer represents a hypothetical concept on each design alternative, deploys and verifies the concept from multiple viewpoints considering other alternatives, and modifies it. An advanced integrated design environment should be based on a representation framework that embodies this process of reflection in concept development, which usually remains in the realm of the designer’s tacit knowledge. This paper proposes a knowledge representation framework for an integrated design environment, named DRIFT (Design Representation Integration Framework of Three layers), which interactively captures and manages reflection processes of generating and verifying design concepts. The core of DRIFT is a three-layered design process model of actions, operations, and argumentation. This model integrates various design tools and captures performed design activities. The action level captures the sequence of design operations. The model operation level captures the transition of design states, recording a design snapshot over design tools, which are integrated through ontology-based representation of design concepts. The argumentation level captures the process of defining problems and corresponding alternative solutions. Integration of three levels with a template of design operation extracted from Design-For-X approaches enables a proposed system to interactively and efficiently capture and manage the process of design concept development through operations over design tools. A design operation template works to limit the number of links between the three levels remaining easy to manage its semantics. This paper also demonstrates a prototype implementation of DRIFT and its application to conceptual design of a small mechatronic system with a system modeling method. The paper concludes with a discussion of some future issues.     

Communication Spaces

Concepts of space are fundamental to our understanding of human action and interaction. The common sense concept of uniform, metric, physical space is inadequate for design. It fails to capture features of social norms and practices that can be critical to the success of a technology. The concept of ‘place’ addresses these limitations by taking account of the different ways a space may be understood and used. This paper argues for the importance of a third concept: communication space. Motivated by Heidegger’s discussion of ‘being-with’ this concept addresses differences in interpersonal ‘closeness’ or mutual-involvement that are a constitutive feature of human interaction. We apply the concepts of space, place and communication space to the analysis of a corpus of interactions from an online community, ‘Walford’, which has a rich communicative ecology. A novel measure of sequential integration of conversational turns is proposed as an index of mutal-involvement. We demonstrate systematic differences in mutual-involvement that cannot be accounted for in terms of space or place and conclude that a concept of communication space is needed to address the organisation of human encounters in this community.