面向并行工程的多域特征映射方法学研究

讨论了特征的概念性和操作性定义及特征分类,分析了多域特性映射机理,给出了不同应用领域对产品信息需求的多域特征映射框架模型和实现过程。     

Manufacturing features recognition using backpropagation neural networks

A backpropagation neural network (BPN) is applied to the problem of feature recognition from a boundary representation (B-rep) solid model to facilitate process planning of manufactured products. It is based on the use of the face complexity code to represent the features and a neural network for the analysis of the recognition. The face complexity code is a measure of the face complexity of a feature based on the convexity or concavity of the surrounding geometry. The codes for various features are fed to the network for analysis. A backpropagation network is implemented for recognition of features and tested on published results to measure its performance. Any two or more features having significant differences in face complexity codes were used as exemplars for training the network. A new feature presented to the network is associated with one of the existing clusters, if they are similar, or the network creates a new cluster, if otherwise. Experimental results show that the network was consistent in recognizing features, hence is appropriate for application to the problem of feature recognition in automated manufacturing environment.     

肺癌早期诊断系统中形态学识别的研究与实现

讨论了通过利用细胞图象中的形态学信息对肺癌细胞进行识别和检测的方法。该方法采用基于区域边界的链码方提取形态学特征,再根据形态学识别算法,对细胞自动进行分类,从而识别出图象中的肺癌细胞。     

一种基于目标红外特征的目标分类识别方法

基于目标的红外选择性,提出了目标的９个特征量,并以它们为分量组成目标的特征向量,以此来进行目标的分类识别。由于特征量单位不统一,提出了一种近邻分类法。文中用３类飞机的红外图像进行实验。实验表明,用这种方法把提出的红外特征量用于目标的分类识别效果很好。     

建厂三十年的浦项钢铁公司及其经营特征

概述韩国浦项钢铁公司概况,包括现有设备、海外投资项目和对占领中国市场的策略,以及公司近几年生产、销售和赢利情况;探讨该公司发展取得成功的经营特征;并介绍该公司1998年的经营方针和管理目标为继续维持高生产率和大量销售传统,采取紧缩政策,建立“经济增值”先进管理技术和“全球共同文化”。     

特殊轴承保持架摩擦特性试验研究

本文论述了特殊轴承结构特点,摩擦副工作特性,对５种保持架材料进行摩擦特性对比试验。结果锌基合金ＺＡ２７,ＺＡ２７ｓ比ＺＨＭｎ５８－２－２,ＺＱＳｎ６－３－３,ＺＱＳｎ１０－１强度高,摩擦系数小,但与４５°调质钢对磨损损量较大,最后选定ＺＡＳｎ１０－１为特殊轴承保持架材料,并通过实践证明这种匹配的特殊轴承摩擦副质量可靠,完全可以替代此类进口轴承。     

A model for evaluating the quality of the fixturing of the part from a machining process planning perspective

Achieving the required tolerance of positioning between two features is not obvious when features are produced in multiple set-ups where the fixture/workpiece interface plays a critical role. From a computer-aided process planning perspective, the suitability of a fixturing feature to achieve the required tolerances has to be evaluated. A model of an indicator for a locating quality is proposed here based upon the distribution of a small displacement of the workpiece compatible with the required tolerance onto the candidate fixturing surfaces.     

基于子波变换的纹理图像分类

本文用子波变换的方法描述了纹理图像多尺度、多方向的特性,提出了适合于纹理图像分类的新的子波特征。通过对其稳定性和视觉特性的详细分析,指出此特征优于传统的能量特征。文章最后结合九类自然纹理图像,分别基于标准子波特征、子波包特征用BP神经网络进行了分类识别。实验结果表明,在无噪声情况下,对自然纹理图像可无误差分类;在有噪声情况下,正确分类识别率高,表现出强的稳定性。     

从GAR模型参数提取特征的数字调制识别新方法

本文提出了一种从观察序列的广义自回归(GAR)模型参数提取待识别信号的伪瞬时中心频率和伪瞬时3dB带宽特征,并利用神经网络分类器的数字调制识别新方法。这种方法充分利用了GAR模型良好的抗噪声能力和神经网络优异的模式分类能力,能有效地改善低SNR条件下的调制识别性能。计算机模拟结果证实了该方法具有很高的识别率和良好的稳健性。     

周口坳陷的逆冲推覆构造特征

周口坳陷位于华北盆地南部,是在华北地块、华北地块南缘构造带这两个构造单元基础上发育的大型中、新生代断拗型坳陷。该坳陷有６条主要逆冲断裂,走向均为北西西向,剖面上有叠瓦式和对冲式两种构造组合样式,逆冲方向指向北北东方向,太古界至新生界不同程度地被卷入逆冲推覆系统,逆冲推覆构造是坳陷内最重要且独具特色的构造形迹。该坳陷推覆活动具有多期性、继承性和差异性等特点,早白垩世末期的逆冲推覆活动是印支晚期至燕山早期华北板块与扬子板块之间陆陆叠覆造山运动的结果,早第三纪末期以来的逆冲推覆活动则与秦岭—大别造山带晚近时期的差异块断和走滑作用有关。图４参６（王孝陵摘