双通道激光图像数据采集与通讯系统的研制

本文概述了在激光三维成像系统中的数据采集及其计算机通讯技术，介绍了高速Ａ／Ｄ转换器ＡＤ５７９与ＣＡ３３１８的功能及其在系统中的应用，探讨了系统各部分时序控制电路以及与计算机ＤＭＡ通讯的实现．     

应用Java网络进行计算机图学的远程教学系统

计算机图形技术已应用于不同的领域：如教育、商业和科学等，为使学生在Ｉｎｔｅｒｎｅｔ上理解计算机图形学的算法，我们开发了计算机图形学（ＣＧ）教育系统。计算机网络的作用为：通过ＷｏｒｌｄＷｉｄｅ Ｗｅｂ（ＷＷＷ），散居的人们利用文字、图象和声音等进行通讯。我们在网络上开发了计算机辅助教学系统（ＣＡＩ），以帮助每个学生独立地学习计算机图形学。构造ＣＡＩ系统的概念如下；（１）易于理解的手册；（２）可多人独     

离子束辅助沉积制备多晶Al2O3薄膜

利用电子枪蒸镀Ａｌ２Ｏ３，同时辅以Ａｒ离子轰击的离子束辅助沉积方法（ＩＢＡＤ）制备Ａｌ２Ｏ３薄膜，并与单纯电子枪蒸镀方法（ＰＶＤ）制备的薄膜进行了结构和表面形貌的比较，ＩＢＡＤ法可以得到结构均匀致密的γ－Ａｌ２Ｏ３晶态薄膜，而ＰＶＤ９方法仅能得到非晶态疏松的结构，分析结果表明，薄膜沉积过程中，提高离子轰击能量和增加基片加热温度在一定程度上具有相同的效果。     

TIANDA 9188 GIANT（巨星）宽景彩扩机

ＴＩＡＮＤＡ９１８８ＧＩＡＮＴ（巨星）宽景彩扩机９４年上海天马摄影电子仪器厂在ＴＩＡＮＤＡ９１８Ｌ全电脑彩扩设各的基础上扩展功能，推出了ＴＩＡＮＤＡ９１８８ＧＩＡＮＴ（巨星）宽景彩扩机。该机极其完备的功能，必将成为用户之首选机型。其主要功能有：一、采...     

SIS扩声系统设计

ＳＩＳ扩声系统的中文意思是空间成像系统,ＳＩＳ的概念是由英国的ＤＤＡ公司首先提出的,它是英文Ｓｐａｔｉａｌ　Ｉｍａｇｅ　Ｓｙｓｔｅｍ的字头缩写。实际上,ＳＩＳ并不完全是一个新的音响技术理论,确切地说,它是ＤＤＡ的ＣＳ系列调音台上一个新功能的商标,ＳＩＳ功能被ＤＤＡ公司研制和开发出来后、就申报了专利,可以说,ＳＩＳ是一项实用新型专利技术,这项技术确实有其实用性、新颖性和创造性。 大家可能会发现,ＤＤＡ调音台的说明书上只要提到ＳＩＳ就一定要在ＳＩＳ的右上方标一个小的ＴＭ符号,ＴＭ的中文意思就是商标（…     

工业企业CAD和MIS系统的一体化设计

本文介绍了ＣＡＤ系统和ＭＩＳ系统的构成和数据特点，以及工业企业ＣＡＤ和ＭＩＳ系统的一体化设计方法。     

AV新视点

ＡＶ新视点ＤＶＤ的新动态在ＩＦＡ９７上，欧洲ＤＶＤ的伴音格式ＭＰＥＧ２已得到世界五大影视软件生产者华纳、环球、米高梅、哥伦比亚三星、宝利金娱乐的支持，并准备推出１００部具有ＭＰＥＧ２格式的软件，会上还展示了新的ＤＶＤ机型和Ａ／Ｖ接收机。其中具有ＭＰＥ...     

LAN／ATM互连及仿真B—ISDN业务的研究

通过对ＩＥＥＥ８０２．３ＬＡＮ支持实时业务的探讨，提出了ＬＡＮ透明传输Ｂ－ＩＳＤＮ业务的概念，对其路由选择，仿真Ｂ－ＩＳＤＮ业务等问题进行了研究，并给出了具体实现的途径。     

SIGMA—DELTADAC板的设计技术

介绍了一种新型的ＤＡＣ板──ＳＩＧＭＡ－ＤＥＬＴＡ ＤＡＣ的设计技术,给出了ＤＡＣ板的设计原理框图,详细叙述了ＳＩＧＭＡ－ＤＥＬＴＡ ＤＡＣ的硬件设计及软件调试结果。     

SIGRAPH—DESIGN环境下的机构装配设计技术

研究了在智能ＣＡＤ系统ＳＩＧＲＡＰＨ－ＤＳＩＧＮ环境下进行机构装配设计的途径，给出了要领设计，装配设计和零件设计的一般方法，并以胶印机中凸轮一连杆机构为例，采用自顶向下的装配设计方法，     

多核集群任务分配问题的0-1整数规划求解模型

研究了典型多核集群任务分配中的节点内通讯特性。基于0-1整数非线性规划模型和线性松弛技术,给出了一种0-1整数线性规划任务分配问题求解优化模型。由于节点内的通讯量与通讯延迟较大,以最小化计算代价和节点间通讯代价为研究目标的传统求解模型具有严重的局限性,而该求解模型考虑了节点内通讯代价,并采用了线性规划松弛技术,其目标是最小化计算代价、节点间通讯代价和节点内通讯代价。计算结果验证了提出的模型的有效性。     

基于CORDIC的成像声呐加权系数实时生成方法研究

针对线列阵成像声呐加权系数的预存储式生成方法,需要在现场可编程门阵列(Field Programmable Gate Array,FPGA)中调用Block Memory IP核预存所有加权系数进行波束形成,造成随机存储器(Random Access Memory,RAM)资源占用过多的问题,提出了一种基于CORDIC实时生成加权系数的改进方法。通过预存少量的波束角度值并利用乘法器和CORDIC IP核实时生成加权系数,该方法可降低77%的RAM资源;此外,通过上位机下发声速,可以实现动态加载不同声速下的加权系数进行波束形成,并且能够保持较高的运算效率。经过ISE布局布线,该方法有效地均衡了RAM资源与逻辑资源的占用率,节省FPGA成本,具有很好的工程应用价值。     

Health monitoring of concrete structures strengthened with advanced composite materials using piezoelectric transducers

An active damage interrogation (ADI) method which uses an array of piezoelectric (PZT) transducers attached to a structure was used to detect and localize disbonds and delaminations of advanced composite reinforcement from concrete structures. The ADI system provides the ability to detect, localize, and estimate the extent of the disbond by actively exciting the structure with PZT transducers and processing the structural response as measured by the PZT transducers. The ADI system makes use of both amplitude and phase information from various actuator/sensor transfer functions, and also provides a unique method for determining when the transducer/structure bond has degraded. This paper investigates the feasibility of using the ADI method for health monitoring of concrete structures repaired with composite materials, and the advantages and limitation of this method are discussed.     

A domain decomposition implementation of the SIMPLE method with PVM

A parallel implementation of a finite volume method for the solution of the Navier-Stokes equations on a distributed computing environment through Parallel Virtual Machine (PVM) is reported. The numerical method is implicit and is based on the SIMPLE algorithm in which the system of equations is discretised using a hybrid scheme. An Alternative Direction Implicit (ADI) scheme, and the Thomas tri-diagonal solver are used to solve the algebraic equations. The parallelization of the program is implemented by a domain decomposition strategy on MIMD parallel architectures using PVM platform. The program was tested for laminar flow in a cavity. The parallelisation strategy and performance are discussed. It is concluded that the efficiency is strongly dependent on the grid size, block numbers and the number of processors. Different strategies to improve the computational efficiency are proposed.     

The application of scalable distributed memory computers to the finite element modeling of electromagnetic scattering

Large-scale parallel computation can be an enabling resource in many areas of engineering and science if the parallel simulation algorithm attains an appreciable fraction of the machine peak performance, and if undue cost in porting the code or in developing the code for the parallel machine is not incurred. The issue of code parallelization is especially significant when considering unstructured mesh simulations. The unstructured mesh models considered in this paper result from a finite element simulation of electromagnetic fields scattered from geometrically complex objects (either penetrable or impenetrable.) The unstructured mesh must be distributed among the processors, as must the resultant sparse system of linear equations. Since a distributed memory architecture does not allow direct access to the irregularly distributed unstructured mesh and sparse matrix data, partitioning algorithms not needed in the sequential software have traditionally been used to efficiently spread the data among the processors. This paper presents a new method for simulating electromagnetic fields scattered from complex objects; namely, an unstructured finite element code that does not use traditional mesh partitioning algorithms. © 1998 This paper was produced under the auspices of the U.S. Government and it is therfore not subject to copyright in the U.S.     

A DISTRIBUTED FINITE ELEMENT METHOD FOR SOLVING THE INCOMPRESSIBLE NAVIER–STOKES EQUATIONS

The potential for using a network of workstations for solving the incompressible Navier–Stokes equations using a finite element formulation is investigated. A programming paradigm suitable for a heterogeneous distributed workstation environment is developed and compared to the traditional paradigm employed for distributed memory parallel computers. In particular, the issues of load balancing and fault recovery are explored. Numerical results are presented for two computer configurations: (1) a homogeneous network of workstations and (2) a heterogeneous network of workstations. The superiority of the developed paradigm over the traditional paradigm employed for distributed memory parallel computers is shown in cases where a heterogeneous network of workstations is employed or when one of the workstations of the cluster is loaded by other users.     

Anarchic manufacturing

This paper introduces anarchic manufacturing, an extremely distributed planning and control philosophy, as the methodology for planning and controlling future smart factories. Anarchic manufacturing delegates decision-making authority and autonomy to the lowest level of entities in system elements with no centralised control or oversight. It is often postulated that traditional hierarchical structures may not be well suited to manage the state-of-the-art hyper-connected smart factories due to their reliance on communication between management layers. Distributed systems, on the other hand, are commonly perceived to be inherently more flexible, robust and adaptable than hierarchical systems due to their structure. This paper characterises distributed systems by evaluating the relative flexibility of a representative hierarchical system against an anarchic system in a job shop scenario. Multi-agent-based simulation is used to model both hierarchical and anarchic systems, which are tested for flexibility following the Taguchi method and compared against Taillard's benchmark job shop problems for overall performance. The results show that the anarchic system performs as well as the hierarchical system when subjected to unforeseen disruption, refuting the argument that hierarchical systems are too rigid and distributed systems are inherently more flexible. However, anarchic manufacturing systems, which show adaptability and self-optimising traits, provide a platform to potentially enable the emerging digital manufacturing paradigm through the free market structure especially when bandwidth for communications is limited.     

基于矢量DSP的并行化卷积算法

为了提场卷积算法在矢量!字信号处理器(DSP)上的执行效率,提出了一种高效的并行化卷积算法——基2并行短卷积(PSC R2)算法。该算法采用了基2短卷积运算结构,摆脱了传统并行化卷积算法的直接结构,从而有效降低了算法的循环次!。基于该算法结构,还提出了矢量DSP专用指令以匹配卷积的运算结构,保障算法执行效率。通过实际评估,证明了该算法在时间复杂度上仅为传统的内循环矢量化(VIL)算法的43%,为外循环矢量化(VOL)算法的55%,并且在存储空间开销上能够与传统算法基本持平。利用该算法,可以大幅降低移动通信和数字信号处理中的卷积、相关、滤波运算的时间复杂度。     

Vademecum‐based GFEM (V‐GFEM): optimal enrichment for transient problems

This paper proposes a generalized finite element method based on the use of parametric solutions as enrichment functions. These parametric solutions are precomputed off‐line and stored in memory in the form of a computational vademecum so that they can be used on‐line with negligible cost. This renders a more efficient computational method than traditional finite element methods at performing simulations of processes. One key issue of the proposed method is the efficient computation of the parametric enrichments. These are computed and efficiently stored in memory by employing proper generalized decompositions. Although the presented method can be broadly applied, it is particularly well suited in manufacturing processes involving localized physics that depend on many parameters, such as welding. After introducing the vademecum‐generalized finite element method formulation, we present some numerical examples related to the simulation of thermal models encountered in welding processes. Copyright © 2016 John Wiley & Sons, Ltd.     

Analysis of the Effectiveness of the Method of Qualification Tests for Satellite Communications Earth Stations

Measurement Techniques - We analyze the effectiveness of the qualification test method for communications satellite earth stations, implemented using a multi-user distributed measurement control...