基于自顶向下的减速器三维特征建模

针对现有三维CAD工具在自底向上产品设计建模方面存在的不足,提出了自顶向下设计的概念,给出了自顶向下的装配设计系统开发程序,构建产品的布局,提供了一个面向装配的设计环境,通过层次化的装配模型和参数化的建模技术,由产品的关键零件约束产生其它的零、部件,支持了产品从概念设计到详细设计,以Pro/ENGINEER软件为平台,减速器产品为对象进行了实际应用。     

基于UG/WAVE的柴油机连杆组自顶向下参数化设计

介绍了传统零件设计的缺陷和UG/WAVE的优点,并利用UG/WAVE技术以及参数化建模思想对某柴油机连杆组件进行了自顶向下参数化设计,减少了设计更新及等待的时间,提高了产品的市场竞争能力。     

逆作法工艺在某高层建筑上的应用

针对高层建筑日益增多的趋势,为了安全施工和环境效益,介绍了逆作法施工的原理、分类、工艺特点以及逆作法施工方案。     

Interpreting chicken-scratch: Lexical access for handwritten words.

Handwritten word recognition is a field of study that has largely been neglected in the psychological literature, despite its prevalence in society. Whereas studies of spoken word recognition almost exclusively employ natural, human voices as stimuli, studies of visual word recognition use synthetic typefaces, thus simplifying the process of word recognition. The current study examined the effects of handwriting on a series of lexical variables thought to influence bottom-up and top-down processing, including word frequency, regularity, bidirectional consistency, and imageability. The results suggest that the natural physical ambiguity of handwritten stimuli forces a greater reliance on top-down processes, because almost all effects were magnified, relative to conditions with computer print. These findings suggest that processes of word perception naturally adapt to handwriting, compensating for physical ambiguity by increasing top-down feedback. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dual-Metal Interbonding as the Chemical Facilitator for Single-Atom Dispersions

Atomically dispersed catalysts, with maximized atom utilization of expensive metal components and relatively stable ligand structures, offer high reactivity and selectivity. However, the formation of atomic-scale metals without aggregation remains a formidable challenge due to thermodynamic stabilization driving forces. Here, a top-down process is presented that starts from iron nanoparticles, using dual-metal interbonds (Rh Fe bonding) as a chemical facilitator to spontaneously convert Fe nanoparticles to single atoms at low temperatures. The presence of Rh Fe bonding between adjacent Fe and Rh single atoms contributes to the thermodynamic stability, which facilitates the stripping of a single Fe atom from the Fe nanoparticles, leading to the stabilized single atom. The dual single-atom Rh–Fe catalyst renders excellent electrocatalytic performance for the hydrogen evolution reaction in an acidic electrolyte. This discovery of dual-metal interbonding as a chemical facilitator paves a novel route for atomic dispersion of chemical metals and the design of efficient catalysts at the atomic scale.     

Graph Traversal and Top-Down Evaluation of Logic Queries

In this paper,an optimal method to handle cyclic and acyclic data relations in the linear recursive queries is proposed.High efficiency is achieved by integrating graph traversal mechanisms into a top-down evaluation.In such a way,the subsumption checks and the identification of cyclic data can be done very efficiently.First,based on the subsumption checks,the search space can be reduced drastically by avoiding any redundant expansion operation.In fact,in the case of non-cyclic data,the proposed algorithm requires only linear time for evaluating a linear recursive query.On the other hand,in the case of cyclic data,by using the technique for isolaiting strongly connected components a lot of answers can be generatded directly in terms of the intermediate results and the relevant path information instead of evaluating them by performing algebraic operations.Since the cost of generating an answer in much less than that of evaluating an answer by algebraic operations,the bime consumption for cyclic data can be reduced by an order of magnitude or more.     

自顶向下的计算机辅助工业设计几何建模研究

基于通用设计理论,研究了自顶向下的计算机辅助工业设计几何建模过程,采用面向设计演进过程的元模型和面向工业设计方面各侧面的子模型作为组织几何建模过程的抽象层次,提出了基于有向图的层次化几何信息模型,实现了对设计历史及意图的记录、不同层次几何信息间的关联以及按照元模型和子模型组织的自顶向下的计算机辅助工业设计几何建模过程。     

印刷体数学公式识别中的结构分析策略

数学公式识别是OCR技术的重要组成部分，目前相关的研究还很欠缺。文中在简要介绍数学公式识别发展状况的基础上，针对结构分析这一公式识别的关键环节，提出了一种将“自顶向下”和“自底向上”策略相结合的数学公式结构分析方法。实验表明，这种方法对公式结构具有较好的适应性。     

台北都会区逆作深开挖安全监测系统施工规划暨管理模式研究

采用搜集台北都会区逆作法开挖的案例安全监测纪录，通过文献的回顾，逆作法管理值建立，以及与顺作法管理值的差异，建立监测管理值，并与顺作法管理值比较，针对逆作法安全监测的施工管理规划模式透过案例的观测值采用安全监测系统来建立台北都会区逆作深开挖安全监测的管理值，得出了台北都会区逆作深开挖法观测值模式的结果。     

虚拟环境中的快速产品装配建模

提出虚拟环境中“堆积木”式的快速产品装配建模方法,使设计人员可以方便地进行结构设计、修改,专注于产品功能的实现;介绍了与此方法相适应的配合约束的识别方法,提出“零件偏置体”的概念以便提高识别效率;并以关系图的方式记录识别到的配合约束关系,最终形成约束驱动的产品装配模型,从而有力地支持Ｔｏｐ－ｄｏｗｎ设计过程中装配体的演化。