Statistical theory of active radar systems for remote probing of natural environment

Optimal algorithms for obtaining radar images of the Earth's surface by means of active remote probing are determined on the basis of the theory of statistical solutions.Translated from Izmeritel'naya Tekhnika, No. 1, pp. 57–60, January, 1995.     

A CAD-linked virtual assembly environment

This paper presents a novel approach to integrate VR and CAD for virtual assembly, namely, CAD linked virtual assembly environment. Compared with most existing VR and CAD integration approaches, the proposed approach is a kind of external integration with a CAD system through automation interfaces. A novel hybrid virtual assembly model is developed in this paper to support this external integration. It works as a combinator that links the precisely represented design dataset in CAD models and the corresponding hierarchically structured virtual assembly dataset in the VR application. With this model, a framework has been developed to embed and apply CAD assembly constraints on the virtual assembly structure. Constraint-based manipulation is then implemented in the virtual assembly environment. Moreover, with this framework, advanced computations, such as runtime DOF determination, disassembly directionality computation, and assembly/disassembly sequence generation, which rely on assembly constraint information, can be feasibly integrated into the virtual assembly application with much less effort. The approach is also more practical in terms of implementation due to two advantages: (1) It does not require the implementation of a complicated support for solid modelling in the virtual assembly application. (2) A virtual assembly environment can be automatically created and updated from the linked CAD models.     

Multimedia textbook for virtual education environment

This paper discusses a proposed multimedia textbook to be implemented in a virtual education environment (VEE) at the Multimedia University in Cyberjaya, Malaysia. The aim of the multimedia textbook, which is targeted at engineering courses, is to bring out a student's creative abilities and to minimise basic study and learning time so that more subjects can be provided to prepare students for future interdisciplinary R&D and industrial work. The multimedia textbook is designed both for students on-campus and for those scattered locally and internationally. Shorter learning times have already been confirmed using an experimental multimedia textbook having a limited set of interfaces (see, hear, click). The remaining interfaces will be implemented next and AI software included to enable a students learning behaviour to be monitored and to customise learning materials according to the student's level of understanding     

A virtual environment for training overhead crane operators: real-time implementation

In a manufacturing enterprise, virtual environments can improve productivity by allowing employees to train without taking production equipment out of service. As a demonstration of this capability, we have developed a virtual environment to simulate overhead crane operation. This virtual environment was developed by combining 3-D factory drawings with 3-D simulation models of crane and load motion. The crane simulator allows an operator to maneuver a crane and load in three dimensions. Implemented on a PC with an update rate of 14.3 Hz, the simulator runs in real-time interaction that approximates live machinery.     

复杂环境沉井施工爆破振动远程综合监测系统

由于沉井施工埋置深度较大,施工技术要求较高,复杂环境下常需进行多次爆破作业,且施工工艺不合理时容易导致工程事故的发生,故需对沉井施工爆破振动信号进行监测与分析处理,以便预测和控制爆破振动效应。针对复杂环境下沉井施工爆破振动监测,利用虚拟仪器技术、数据库技术、无线通信技术、Web技术,建立一个集爆破振动数据采集、存储、传输、多终端查看于一体的多传感器爆破振动远程综合监测系统。系统由数据采集层、数据传输层、Web应用层、客户端四部分组成,能够实现多传感器信号的同时采集、显示与传输,并实现远程多终端实时快速查看爆破振动监测结果,便于及时对数据进行处理。     

复杂环境沉井施工爆破振动远程综合监测系统

由于沉井施工埋置深度较大,施工技术要求较高,复杂环境下常需进行多次爆破作业,且施工工艺不合理时容易导致工程事故的发生,故需对沉井施工爆破振动信号进行监测与分析处理,以便预测和控制爆破振动效应。针对复杂环境下沉井施工爆破振动监测,利用虚拟仪器技术、数据库技术、无线通信技术、Web技术,建立一个集爆破振动数据采集、存储、传输、多终端查看于一体的多传感器爆破振动远程综合监测系统。系统由数据采集层、数据传输层、Web应用层、客户端四部分组成,能够实现多传感器信号的同时采集、显示与传输,并实现远程多终端实时快速查看爆破振动监测结果,便于及时对数据进行处理。     

A distributed virtual factory in agile manufacturing environment

There is a growing recognition that current manufacturing enterprises must be agile, that is, capable of operating profitably in a competitive environment of continuously changing customer demands. The use of a virtual enterprise (VE) is becoming increasingly prevalent, and that has been made possible, in part, due to the significant advances in communication and information technology in recent years. A manufacturing system is one of the competitive factors that forms an effective VE. Therefore, for manufacturers wishing to obtain a contract in VE, it is crucial to present attractive and competitive offers to other coalition members. There are several criteria to these offers, such as cycle time, fulfilment of due date or quick shipping date, cost, and quality assurance for the ordered products. Manufacturing system simulation could endorse the basic estimates of the criteria for the strategic offer. The distributed simulation model concept provides practical solutions to facilitate such a large-scaled precise simulation model in the VE environment, because it is constructed as the integration of several manufacturing simulation models of each production module in the factory. As a solution to realize this integration, we propose a Distributed Virtual Factory (DVF) concept that consists of distributed precise simulation models connected by several synchronization mechanisms named Time Bucket algorithms. A DVF enables precise evaluations of the whole manufacturing system, especially in terms of the material flows. In this study, we introduce an Activity Based Costing (ABC) method into the DVF architecture to estimate the detailed cost analysis of the products. The methodology facilitates strategic enterprise management to prepare the request for the bids in the VE environment. The effectiveness of the proposed concept in agile manufacturing is discussed with simulation experiments.     

虚拟仪器远程控制的研究

本文研究了由计算机控制的虚拟仪器的远程控制问题.总结了虚拟仪器的特点以及对远程控制的要求,并以HS801虚拟电子仪器为例,分析其动态连接库,并对其远程控制进行了初步的实践.     

虚拟仪器远程控制的研究

本文研究了由计算机控制的虚拟仪器的远程控制问题.总结了虚拟仪器的特点以及对远程控制的要求,并以HS801虚拟电子仪器为例,分析其动态连接库,并对其远程控制进行了初步的实践.     

Incorporating contact sensing in virtual environment for roboticapplications

Many robotic tasks involve dynamic interaction between the work piece and handling device, in which sensory information constitutes an indispensable part of the task. It is therefore of practical interest to incorporate sensor modules in the simulation stage to provide a more realistic preview of the operation and predict the behavior of the components prior to the implementation on a real work cell. Most of the current virtual reality (VR) systems use geometric models and sensorless robots for simulation, which cannot provide the insight into the real behavior of the work cell components. In this paper, we report our work in studying the issues related to simulated sensors for dynamic interaction in virtual environment (VE) using physics based models. Based on previous development, a simplified force sensor is modeled and simulated. The current implementation was carried out on a PC based VR platform, with the low-level programs developed using C via the systems development interface (SDK)     

A light pulser system for testing photomultiplier-based counter systems

A light pulser system is described which is intended for the testing of large particle detection systems which use photomultipliers. Scintillation and Cherenkov counter light pulses can be simulated, through adjustment of pulse amplitude and time constants. Individual light pulses can be turned on or off, thus allowing the detailed simulation of complex configuration to allow the testing of not only the detectors but also of any logic system using their outputs. Relative time stabilities of 170 ps (standard deviation) were achieved in a large system, while observed times using real particles were within ± 2 ns (1 ns standard deviation) of those predicted using the LED system.     

A computational control implementation environment for automated manufacturing systems

This paper presents a computational environment as a tool for supporting the implementation of control coding of an automated manufacturing system. The proposed environment considers a cyclic three-stage control development – modelling, synthesis and implementation – until the real system accomplishes the required specification, resulting in the automated and integrated manufacturing system. The research details the three stages and describes the steps executed for each one. The mathematical formalism used in this work is also presented, as a basis for control implementation. The implementation environment is proposed in order to validate the control structure of this formalism and to allow a progressive integration of control hardware and software. To submit to a test and validate the proposal environment, two experiments are performed, in two different manufacturing systems. Thus, it is demanded that the control system can be reconfigurable in a fast and reliable way.     

基于FPGA的高速并行光通信误码率测试系统

利用高性能、低成本的现场可编程门阵列(FPGA)芯片、个人电脑和应用软件研制出了可应用于高速并行光通信系统误码率测试的虚拟测试系统。此系统可对不同速率与通信格式的多通道并行光通信系统进行误码率测试,支持对速率为10Gb/s的VSR4-1.0协议的甚短距离光传输(VSR)系统的误码测试。该系统最多可支持12条测试信道,单信道最高测试速率为1.25Gb/s,为研制高速并行光通信系统提供了一个方便、快捷、灵活的初级误码率测试手段。该系统可降低并行通信系统的研发成本,缩短测试周期,提高工作效率。     

面向远程布局的分布式虚拟车间研究

提出了面向透视关系一致性的图像插值策略和基于敏感视野的渲染精度分配策略,采用基于图像的柱面纹理映射方法实现了基于Web的分布式虚拟车间系统,解决了面向宜人化水平的车间异地布局评价存在的主要难点问题。     

基于Web Service构建分布式虚拟地理环境系统

在研究了分布式虚拟地理环境系统的特征和基于Web Service、GI Web Service实现分布式虚拟地理环境系统的优势的基础上,建立了基于Web Service的分布式虚拟地理环境系统的体系结构,最后开展了原型系统试验.结果证明,系统实现了在异构环境下的资源共享和协同工作,基本解决了以往C/S、B/S结构的系统中共享资源只能集中存储在服务器端等难点问题.     

上行虚拟MIMO系统的双比例公平用户配对算法

在分析上行虚拟多输入多输出(V-MIMO)系统的传统正交用户配对算法的基础上,提出了一种先按比例公平准则选取第一个用户,然后基于一种改进的比例公平准则选取其配对用户的新的双比例公平(D-PF)用户配对算法,并基于不同的接收机结构分析评估了该算法的吞吐量性能以及用户之间的公平度.仿真结果表明,与传统的正交用户配对算法相比,所提D-PF算法能够取得更好的吞吐量和用户公平度性能.     

A behavior-driven reliability modeling method for complex smart systems

With recent advancements in Internet technologies and wireless communications, wireless sensor network (WSN)-based smart systems are gaining an enormous increase in use in various applications (eg, healthcare, smart home, smart manufacturing, smart power grids, and smart transportation). Due to the mission-critical or safety-critical nature of smart system applications, it is imperative that a smart system be reliable during its mission time. However, reliability analysis and design of smart systems are still open challenging research problems due to complicated dependencies existing in the WSN domain or the physical domain monitored by the WSN, and due to dependencies crossing the two domains. This paper proposes a new behavior-driven reliability modeling methodology for accurate and efficient reliability analysis of complex WSN-based smart systems, contributing toward their robust designs and operations. The suggested method can address effects of dependent behaviors affecting different domains of the smart system in a combinatorial manner. It also enables the use of efficient single-domain reliability methods to retain their efficiency. A case study of a smart home system is performed to demonstrate the application of the proposed method as well as its advantages in handling nonexponential time-to-failure distributions and in analyzing smart systems with complicated intradomain and cross-domain dependencies.     

虚拟仪器在计量测试中的应用

由于微电子技术、计算机技术、软件技术和网络技术的高度发展与不断融合,虚拟仪器技术业已成为当前测试技术领域的-个热点.文章简单地介绍了虚拟仪器技术及其发展状况;列出了新技术给计量测试带来的各种问题;一最后结合工程实践提出了相应的解决方案和注意事项,这对于其它类虚拟仪器的计量具有普遍的参考意义.