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991.
This paper presents an integrated approach that supports the topology optimization and CAD-based shape optimization. The main
contribution of the paper is using the geometric reconstruction technique that is mathematically sound and error bounded for
creating solid models of the topologically optimized structures with smooth geometric boundary. This geometric reconstruction
method extends the integration to 3-D applications. In addition, commercial Computer-Aided Design (CAD), finite element analysis
(FEA), optimization, and application software tools are incorporated to support the integrated optimization process. The integration
is carried out by first converting the geometry of the topologically optimized structure into smooth and parametric B-spline
curves and surfaces. The B-spline curves and surfaces are then imported into a parametric CAD environment to build solid models
of the structure. The control point movements of the B-spline curves or surfaces are defined as design variables for shape
optimization, in which CAD-based design velocity field computations, design sensitivity analysis (DSA), and nonlinear programming
are performed. Both 2-D plane stress and 3-D solid examples are presented to demonstrate the proposed approach.
Received January 27, 2000
Communicated by J. Sobieski 相似文献
992.
Web上多层Client/Server数据库系统的设计与实现 总被引:6,自引:0,他引:6
文章探讨了当今处于Internet技术前沿的可用的远程数据库编程技术,并分析了Web上多层Client/Server数据库系统的原理和结构.提出了一种Web上多层Client/Server数据库系统的解决方案,详述了系统实现的具体方法,以及开发过程中所要解决的关键问题,并实现了主讲教师优秀教案远程参考系统. 相似文献
993.
为了有利于多主体系统的开发,目前急需一种系统建模技术来对系统复杂性进行行之有效的管理。由于面向对象的建模技术已经趋向成熟,该文在面向对象的建模方法的基础上阐述了一种面向主体的建模方法。该方法针对基于一种特定BDI结构的主体,它包括从内部观点建构信念、目标、计划模型( 即所谓的BDI模型 )和从外部观点建构单个主体模型和交互模型。而且,该方法也能容易地进行扩展并应用于其他结构的主体建模。文章对各个模型的建造作出了详细介绍。 相似文献
994.
目前在网络环境下进行多媒体教学,网络速度是一个严重的瓶颈问题。在分析瓶颈产生的基础上,作者提出了一个新的文件传输协议──NFTP(Narrowband File Transfer Protocol窄带文件传输协议),利用广播数据包方法解决多媒体教学中的速度问题,并设计了一组协议原语,用于协议的描述。 相似文献
995.
本文提出了不用艏侧推的船舶定点控位控制方式。其特点是仿效人类航海技巧,充分利用海洋环境作用在船舶上的力来实现船舶的定点控位。仿真结果表明,在高海情下,此控制系统可以实现无艏侧推船舶定点控位,并且在设定点变化时,船舶具有较快的运动响应速度。 相似文献
996.
997.
Chi‐Woo Kim Chang‐Oh Jeong Jean‐Ho Song Hyung‐Guel Kim 《Journal of the Society for Information Display》2001,9(3):139-143
Abstract— TFT‐LCD panels for notebook‐PC applications requires a thin and light form factor, low power consumption, and good display quality, whereas the desktop monitor has different requirements such as large panel size, wide viewing angle, high resolution, brightness, etc. However, for the fifth‐generation of mass production, current panel technologies have to improve in order to cope with these requirements. In this article, various approaches to the manufacturing technologies of next‐generation TFT‐LCDs are discussed. 相似文献
998.
Chen S.-W. Lin S.C. Chang K.E. 《IEEE transactions on systems, man, and cybernetics. Part B, Cybernetics》2001,31(5):842-852
A concept map, typically depicted as a connected graph, is composed of a collection of propositions. Each proposition forming a semantic unit consists of a small set of concept nodes interconnected to one another with relation links. Concept maps possess a number of appealing features which make them a promising tool for teaching, learning, evaluation, and curriculum planning. We extend concept maps by associating their concept nodes and relation links with attribute values which indicate the relative significance of concepts and relationships in knowledge representation. The resulting maps are called attributed concept maps (ACM). Assessing students will be conducted by matching their ACMs with those prebuilt by experts. The associated techniques are referred to as map matching techniques. The building of an expert ACM has in the past been done by only one specialist. We integrate a number of maps developed by separate experts into a single map, called the master map (MM), which will serve as a prototypical map in map matching. Both map integration and map matching are conceptualized in terms of fuzzy set discipline. Experimental results have shown that the proposed ideas of ACM, MM, fuzzy map integration, and fuzzy map matching are well suited for students with high performances and difficult subject materials. 相似文献
999.
Christopher T. Rodenbeck James M. Carroll Robert A. Flynt Kai Chang 《国际射频与微波计算机辅助工程杂志》2001,11(6):396-403
This paper details a new bias‐dependant small‐signal modeling methodology for monolithic PIN diodes. The frequency‐dependent responses of intrinsic p‐i‐n structures are de‐embedded from monolithic microwave integrated circuit PIN diodes of varying size and layout configuration and fit from 6 to 45 GHz to a classical linear model at each of 15 different bias levels. This methodology results in a bias‐dependent intrinsic diode data set that shows excellent agreement with large samples of small‐signal measurements. The models are useful for comparing trade‐offs in electrical performance among PIN diodes of varying size and layout style. © 2001 John Wiley & Sons, Inc. Int J RF and Microwave CAE 11: 396–403, 2001. 相似文献
1000.
This article deals with the depth observability problem of a robot visual system with a moving camera. In the visual system, the unknown depth of a feature point is estimated from the input of the camera velocity and the output of the image of the feature point. Although it is well known that the linear velocity of the camera must satisfy some constraints for successful depth estimation, this proposes a criterion to measure the performance of the depth estimation, which is a heuristic extension from an estimation result of a linear system. This performance criterion depends on both the image position and the linear velocity of the camera. Some simulation and experiment examples demonstrate and verify the proposed performance criterion. Furthermore, this criterion is used to develop a new visual servo control scheme that has good performance in both the depth estimation and the visual control. This control scheme is also verified by a simulation example. © 2001 John Wiley & Sons, Inc. 相似文献