基于两正交向LAG的一种新的矢量编码方法

矢量编码在工程图自动读入系统中占有很重要的地位，本文提出了一种新的矢量编码方法，这种基于两正交向行邻图（ＬＡＧ）进行边缘检测的矢量编码方法，它可以克服单一方向边缘检测的缺点，较好地保留了线段的边缘信息，并具有效高的数据压缩率。文章将论述这一方法的形成、特点及算法，最后给出经矢量编码、模式织别后输出的原图。     

Geometric matching for clip-art drawing retrieval

Currently, there are large collections of clip-art vector drawings from which users can select the desired figures to insert in their documents. However, to locate a particular drawing among thousands is not easy. Although there are some solutions for drawing retrieval, almost all of them are designed to retrieve simple and not complex drawings as for instance clip-arts. In our prior work we proposed an approach to index and retrieve complex vector drawings by content, using topological and geometric information automatically extracted from figures. In this paper, we present a new algorithm to improve the geometric matching of two drawings, which takes into account the drawing as a whole and each of the shapes in it. We developed a web search engine for clip-art drawings, where we included this new technique. Experimental evaluation reveals that this new geometric matching algorithm conducts to better retrieval results than the prior matching solution.     

Rover reaps the benefits of EDM [engineering data management]

When Rover introduced document management in early 1994, it justified the project simply on the basis of providing an engineering drawing database. The system was designed to allow the print room to scan engineering drawings so that users could access them from the desktop rather than having to request hard copy prints. One enhancement, an improved document management release process, was initiated by a request to export CAD files from Rover's engineering data management (EDM) system into the document management system to avoid scanning of CAD drawings. This presented a problem which made the process an ideal candidate for re-engineering using document management to create a new process. This process is described and the benefits gained by Rover are outlined     

线条画矢量化研究

针对图案设计中无法由图像文件直接设计艺术风格的问题,提出一种线条画图像矢量化的方法。现有的研究工作或者根据矢量线条进行图案设计,或者根据图像抽取线条画,文章的工作可以结合这两类方法完成从图像到各种风格的艺术图案的设计。实现过程包括图像二值化、图像细化、线条追踪和宽度获取几个步骤,文章最后给出了实验结果。     

Protel 在有线电视网络规划和管理中的应用

利用Protel可方便地绘制有线电视工程设计方案图纸和网络图纸，并可对网络使用的材料和空余端口进行统计，生成的图纸和报表结构清晰、兼容性强，给出了使用Protel对有线电视网络进行规划和管理的具体方法和技术要点。     

Neural-network learning and Mark Twain's cat

In current practice in the engineering community, neural networks are used as only one useful class of adaptive pattern recognizer. Neural networks, however, are far more than devices that can learn accurate input-output transformation or form good category boundaries for pattern classifiers. They are a new form of computer, good at some unfamiliar problems, but quite poor at some familiar ones. An application involving a neural network learning some elementary arithmetic is discussed. It is shown that a simple network program can be implemented by differential weighting of the input data vector. In favorable cases the programming vector can be estimated by seeing relatively few examples of the output, if the task and the structure of the data allow it. Therefore, easy programming is allowed in only a limited domain, controlled by the data representation     

Virtual meetings with desktop conferencing

Teleconferencing has come a long way since its early days as little more than three-way calling services over the telephone. Today's virtual meetings boil down to collaborative computing on desktops or laptop computers. Using the communications protocol of the Internet, today's desktop conferencing can incorporate audio, video, shared documents and engineering drawings, whiteboard for diagrams, and/or text chat for meetings held in the relative comfort of an office     

一种基于调制特征向量的空目标识别方法

空中目标旋转部件对雷达回波有调制作用。将回波时域幅度调制信息的幅度偏差系数作为调制特征,首先利用仿真数据分析了固定翼飞机目标和直升机飞机目标的差异,随后提出了一种最近邻分类器的设计方法,最后利用实测数据对目标进行分类,取得了较高的识别率。与支持向量机的算法相比,该分类器算法复杂度低,计算量小,识别率高,在工程上可以选用这种方法对两类目标进行分类识别。     

HFC网络工程图纸的绘制

工程图纸在HFC网络建设中具有很重要的作用,从以下几个方面阐述工程图纸的绘制技巧:如何获取用于工程图纸设计的参照图;实地调查的重要性;比例尺转换的好处;工程图纸的绘制方法及形式。     

Fuzzy logic systems for engineering: a tutorial

A fuzzy logic system (FLS) is unique in that it is able to simultaneously handle numerical data and linguistic knowledge. It is a nonlinear mapping of an input data (feature) vector into a scalar output, i.e., it maps numbers into numbers. Fuzzy set theory and fuzzy logic establish the specifics of the nonlinear mapping. This tutorial paper provides a guided tour through those aspects of fuzzy sets and fuzzy logic that are necessary to synthesize an FLS. It does this by starting with crisp set theory and dual logic and demonstrating how both can be extended to their fuzzy counterparts. Because engineering systems are, for the most part, causal, we impose causality as a constraint on the development of the FLS. After synthesizing a FLS, we demonstrate that it can be expressed mathematically as a linear combination of fuzzy basis functions, and is a nonlinear universal function approximator, a property that it shares with feedforward neural networks. The fuzzy basis function expansion is very powerful because its basis functions can be derived from either numerical data or linguistic knowledge, both of which can be cast into the forms of IF-THEN rules     

3-D pain drawings-mobile data collection using a PDA

A large number of the adult population suffers from some kind of back pain during their lifetime. Part of the process of diagnosing and treating such back pain is for a clinician to collect information as to the type and location of the pain that is being suffered. Traditional approaches to gathering and visualizing this pain data have relied on simple 2-D representations of the human body, where different types of sensation are recorded with various monochrome symbols. Although patients have been shown to prefer such drawings to traditional questionnaires, these pain drawings can be limited in their ability to accurately record pain. The work described in this paper proposes an alternative that uses a 3-D representation of the human body, which can be marked in color to visualize and record the pain data. This study has shown that the new approach is a promising development in this area of medical practice and has been positively received by patients and clinicians alike.     

3-D Pain Drawings–-Mobile Data Collection Using a PDA

A large number of the adult population suffers from some kind of back pain during their lifetime. Part of the process of diagnosing and treating such back pain is for a clinician to collect information as to the type and location of the pain that is being suffered. Traditional approaches to gathering and visualizing this pain data have relied on simple 2-D representations of the human body, where different types of sensation are recorded with various monochrome symbols. Although patients have been shown to prefer such drawings to traditional questionnaires, these pain drawings can be limited in their ability to accurately record pain. The work described in this paper proposes an alternative that uses a 3-D representation of the human body, which can be marked in color to visualize and record the pain data. This study has shown that the new approach is a promising development in this area of medical practice and has been positively received by patients and clinicians alike.     

七元非典型声强向量阵对舰船的被动定向和尺度估计

该文提出了利用七元非典型声强向量阵对舰船体积目标3亮点部位定向和定位的方法。基阵的7个阵元都可以布放在水下探测平台表面,并且阵元间的间距可以根据平台尺寸进行调整,便于工程应用。舰船体积目标中部、中后部辐射的低频声源用声强向量法定向,舰船尾部辐射的高频声源用传统的时延估计法定向,两种方法可以在同一基阵上实现。利用实测舰船辐射噪声数据进行了计算机仿真。仿真结果表明:该方法能够实现舰船目标3亮点部位的高精度定向,在信噪比10dB时,定向误差在2以内。并且在探测平台深度已知的情况下,利用定向的结果能够对舰船目标进行尺度估计,估计精度小于船长的10％。     

杂化矢量光场的研究进展（特邀）

偏振是光场的一个重要矢量属性。依据空间偏振分布的不同,可以将光场分为标量光场和矢量光场。其中,非均匀偏振分布的矢量光场在光场传播、聚焦、非线性效应等方面表现出一系列有趣的行为,对其进行深入研究具有重要的科学意义和应用价值。一种在同一波阵面上包含不同偏振态的杂化矢量光场,因其比普通矢量光场具有更丰富的偏振特性,自2010年被发现以来,在光通信、光学操控、量子通信等领域中展现诸多诱人的前景,目前已成为光学领域的一个研究热点。综述着重介绍了杂化矢量光的制备以及其在聚焦、传播和非线性光学等方面中的特性和应用。     

基于脉动阵的自适应波束形成算法仿真

为了满足自适应波束形成技术对实时性的要求,将脉动阵应用于波束形成算法中,以实现自适应权向量的实时获取.通过对QR分解采样矩阵求逆算法、混合型QR分解采样矩阵求逆算法和逆QR分解采样矩阵求逆算法的理论分析,利用脉动阵,对输入数据矩阵进行QR分解,得到旋转因子,实现自适应权向量的实时更新.针对三种算法各自的脉动阵进行仿真,结果表明,基于脉动阵的自适应波束形成算法实现了权向量的高速获取,并为后续的工程实践提供了理论依据.     

归一化自适应预测矢量量化算法压缩SAR原始数据

该文提出归一化自适应预测矢量量化(NAPVQ)算法压缩SAR原始数据。NAPVQ算法先采用矢量线性预测器对输入矢量进行预测,再对原矢量与预测矢量之间的残差矢量进行矢量量化。该算法可视为差分脉冲调制在矢量量化中的拓展,其性能优于块自适应量化(BAVQ)算法以及归一化预测自适应量化(NPAQ)算法。对算法复杂度的进一步分析表明,NAPVQ算法能获得复杂度和性能之间比较合理的折衷,具有实用价值。     

单矢量水听器线谱多目标分辨研究

该文提出了一种通过单个矢量水听器低频线谱检测来分辨多目标的新方法,得出了矢量水听器线谱多目标分辨能力仅与线谱信噪比有关的结论。利用矢量水听器的低频测向能力,通过方位邻近准则实现了多线谱与多目标之间的关联,并采用滤波实现了多目标的分辨与航迹自动跟踪。实测舰船数据的仿真结果表明,该方法采用单个矢量水听器可以分辨互相间隔10的3个目标。方法简单有效,具有工程应用前景。     

Vector quantization in speech coding

Quantization, the process of approximating continuous-amplitude signals by digital (discrete-amplitude) signals, is an important aspect of data compression or coding, the field concerned with the reduction of the number of bits necessary to transmit or store analog data, subject to a distortion or fidelity criterion. The independent quantization of each signal value or parameter is termed scalar quantization, while the joint quantization of a block of parameters is termed block or vector quantization. This tutorial review presents the basic concepts employed in vector quantization and gives a realistic assessment of its benefits and costs when compared to scalar quantization. Vector quantization is presented as a process of redundancy removal that makes effective use of four interrelated properties of vector parameters: linear dependency (correlation), nonlinear dependency, shape of the probability density function (pdf), and vector dimensionality itself. In contrast, scalar quantization can utilize effectively only linear dependency and pdf shape. The basic concepts are illustrated by means of simple examples and the theoretical limits of vector quantizer performance are reviewed, based on results from rate-distortion theory. Practical issues relating to quantizer design, implementation, and performance in actual applications are explored. While many of the methods presented are quite general and can be used for the coding of arbitrary signals, this paper focuses primarily on the coding of speech signals and parameters.     

Synchronization properties in multimedia systems

Multimedia is defined as the integrated generation, representation, processing, storage, and dissemination of independent machine-processable information expressed in multiple time-dependent and time-independent media such as data, graphics, drawings, voice, audio, and video. The characteristics of synchronization mechanisms desirable for central and distributed multimedia systems are addressed. The concept of multimedia objects as components of an object-based model for a multimedia system is introduced. The essential new synchronization requirement is restricted blocking together with synchronization features covering real-time aspects. Existing synchronization mechanisms can be altered or new ones defined to meet these requirements     

虚线跟踪的丢失点判断和修复

在工程图纸的矢量化中,由于虚线点易与背景网格线或其他曲线粘连,不易分割,从而造成跟踪时出现虚线点丢失的现象,影响虚线的自动识别。针对这个问题,提出一种基于距离判据与比值判据的丢失点判断和修复算法。通过对虚线点进行初步分割,然后基于距离判据和比值判据对初分结果进行判断,从而确定是否有丢失点及其所在的位置并修复丢失点。实验证明,通过本算法恢复丢失点,取得了较好的虚线跟踪效果。