燃油计量单元的地面模糊控制器设计

为了进行燃油计量单元地面试验,文中针对某型飞机燃油计量单元,设计出了一种基于高性能单片机的模糊控制器;控制器以80C58单片机为中央处理器,通过检测燃油计量单元输出口的燃油流量来实现步进电机的闭环控制,控制方式采用模糊算法,同时,设计按键模块用于步进电机工作方式的设定;仿真与实验证明,系统超调量为5%,稳态误差控制在±1%,控制速度快、精度高,满足设计要求。     

基于ZigBee的隧道通风自动控制系统

将ZigBee技术与PLC控制技术、变频技术相互融合,提出了基于ZigBee技术的隧道通风自动控制系统。该系统主要由隧道环境检测系统和隧道通风控制系统组成。环境检测系统以CC2430为核心,负责采集隧道内的环境数据,并将该数据通过无线传感网络传送给通风控制系统的控制器;通风控制系统以PLC为核心,可接收环境检测系统所采集的环境数据,并将其与预先设定值进行比较,同时输出信号来控制变频器的输出频率,从而控制风机转速,实现隧道自动通风的目的。测试结果表明:该系统整体工作稳定,操作界面友好,同时验证了无线传感网络数据传输的稳定性。     

全自动柴油十六烷值测定机研究

国内外柴油十六烷值测定机在油样测定过程中,操作人员扮演着极其重要的角色,存在测定结果的准确性受制于操作人员经验的缺陷。对此,进行了柴油十六烷值测定机的自动化研究。在试验过程中：通过控制电磁阀组实现燃油的自动切换及油路的自动清洗;通过流量检测技术及电控单体泵喷油系统的组合控制,实现自动测控燃油流量及自动测控燃油喷射正时;通过电机控制技术及爆震检测技术,实现发动机压缩比的自动调节。对不同油样进行多次测试,测定机的试验结果在重复性和再现性方面符合现行标准。     

基于PID的流量调节阀的设计

针对流量控制,设计了一种结构简单、控制方便、精度高的基于PID的流量调节阀。流量调节阀主要由手动平衡阀、流量传感器、步进电机和控制器四部分组成,控制器采用PID算法控制步进电机。检测步进电机电流的大小不仅能确定手动平衡阀是否到达了极限调节值,也可以防止过电流损坏电机。实验测试中,用PC机对输出流量值进行设定和对流量调节阀的控制效果进行分析。通过反复试验,证明了输出的流量值能准确快速的跟随设定值的变化而变化。研究表明,基于PID的流量调节阀能实现高精度的流量控制。     

飞机燃油系统地面全机模拟试验流量控制系统设计

飞机燃油系统地面全机模拟试验系统流量模拟子系统用于模拟发动机燃油流量;针对某型飞机燃油系统发动机流量范围很大,允许的压力损失却很小的特点,提出分段控制与分段测量的方法;分段控制会带来切换抖动问题,采用基于二自由度模糊自适应PID的控制方法;仿真结果表明,这种方法既可以实现系统大范围流量的跟踪,也可以减小流量切换过程中出现的抖动,有较好的控制效果。     

基于OpenFlow的虚拟机流量检测系统的设计与实现

云平台下的虚拟机在物理机内部交互流量,而不通过防火墙等安全组件。针对这类流量无法在网络边界被获取并检测的问题,分析了OpenFlow技术的原理,提出了一种基于OpenFlow技术将虚拟机流量重定向到入侵检测系统进行检测的方案。方案使用OpenFlow虚拟交换机和控制器替代传统交换机,然后基于OpenFlow技术控制流量转发过程,将其导向外部的安全组件进行处理,并构建了由虚拟交换机、控制单元、入侵检测和系统配置管理4个模块组成的流量检测系统。实验结果表明,系统能够在满足虚拟机网络正常使用的前提下,将待监管流量导向入侵检测系统进行处理,而且能够同时提供交换机级及虚拟机级两种粒度的流量重定向控制。通过对虚拟机引流的方式实现在传统场景中解决云计算环境下流量检测问题,同时能够基于OpenFlow轻松实现流量处理的扩展操作。     

基于PLC的天然气高中压站的智能监控系统研制

介绍了融现代电子技术和微机控制技术为一体的PLC系统在燃气供应系统中的应用，通过压力传感器测量管道燃气的进出口压力、流量计测得燃气流量，并通过PLC的程序转换和输出控制减压阀、增压阀和泄压阀，实现了燃气供应系统的流量控制和远程压力调节。     

基于GPRS和ZigBee的远程油阀控制系统

构建了基于GPRS网络和ZigBee无线通信技术的远程油阀控制系统。该系统的中央监控计算机根据流量调节要求,发送控制命令给ZigBee网络的终端节点。终端节点控制与油阀相连接的步进电机旋转,从而调节流量阀的流量。结果表明,此控制系统能够及时、精确地控制油阀的流量及开关等。     

阀特性影响阀控缸伺服系统跟踪性能仿真分析

在伺服阀控液压缸伺服系统跟踪性能优化控制问题的研究中,有效选择比例伺服阀非常重要,很大程度上决定着系统设计能否达到性能指标要求.对比了四种不同频响和额定流量的比例伺服阀实物,建立了比例伺服阀控液压缸的模型系统.参照实验系统,基于AMESim软件建立了仿真模型.依据所建立的比例伺服阀阀芯动态的数学模型和产品的技术样本,设置了仿真参数,对比研究了不同的阀频响和额定流量对伺服系统跟踪性能的影响.仿真结果表明,比例伺服阀只有具有适宜的固有频率和额定流量才能对控制性能有益.     

基于PIC单片机的粮库监控系统的设计

针对粮库粮食的温湿度采集和控制的问题,设计了一种基于PIC单片机的粮库监控系统。该系统能够实现对每个粮仓粮食温湿度数据的采集;实现对粮仓内通风阀开闭情况的监测并响应主控中心发出的通风阀控制指令;将所采集的数据通过基于网络的通信方式发送给主控中心。粮库监控系统在实际中的应用情况表明,该系统信息采集数据准确,数据传输实时误码率低,整体系统可靠性高。     

Only connect: teaching, technology and telesis

Abstract This paper describes an approach to the design of interactive multimedia materials being developed in a European Community project. The developmental process is seen as a dialogue between technologists and teachers. This dialogue is often problematic because of the differences in training, experience and culture between them. Conditions needed for fruitful dialogue are described and the generic model for learning design used in the project is explained.     

European Community policy and the market

Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.     

一种自适应子融合集成多分类器方法

融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。     

Avoiding semantic and temporal gaps in developing software intensive systems

Development of software intensive systems (systems) in practice involves a series of self-contained phases for the lifecycle of a system. Semantic and temporal gaps, which occur among phases and among developer disciplines within and across phases, hinder the ongoing development of a system because of the interdependencies among phases and among disciplines. Such gaps are magnified among systems that are developed at different times by different development teams, which may limit reuse of artifacts of systems development and interoperability among the systems. This article discusses such gaps and a systems development process for avoiding them.     

Designing economic np control charts: A programmed simulation approach

This paper presents control charts models and the necessary simulation software for the location of economic values of the control parameters. The simulation program is written in FORTRAN, requires only 10K of main storage, and can run on most mini and micro computers. Two models are presented - one describes the process when it is operating at full capacity and the other when the process is operating under capacity. The models allow the product quality to deteriorate to a further level before an existing out-of-control state is detected, and they can also be used in situations where no prior knowledge exists of the out-of-control causes and the resulting proportion defectives.     

The development of robot art

Going through a few examples of robot artists who are recognized worldwide, we try to analyze the deepest meaning of what is called “robot art” and the related art field definition. We also try to highlight its well-marked borders, such as kinetic sculptures, kinetic art, cyber art, and cyberpunk. A brief excursion into the importance of the context, the message, and its semiotics is also provided, case by case, together with a few hints on the history of this discipline in the light of an artistic perspective. Therefore, the aim of this article is to try to summarize the main characteristics that might classify robot art as a unique and innovative discipline, and to track down some of the principles by which a robotic artifact can or cannot be considered an art piece in terms of social, cultural, and strictly artistic interest. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

Explanation and prediction: an architecture for default and abductive reasoning

Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given.     

Three Process Perspectives: Organizations, Teams, and People

This paper provides the author's personal views and perspectives on software process improvement. Starting with his first work on technology assessment in IBM over 20 years ago, Watts Humphrey describes the process improvement work he has been directly involved in. This includes the development of the early process assessment methods, the original design of the CMM, and the introduction of the Personal Software Process (PSP)^SM and Team Software Process (TSP){^SM}. In addition to describing the original motivation for this work, the author also reviews many of the problems he and his associates encountered and why they solved them the way they did. He also comments on the outstanding issues and likely directions for future work. Finally, this work has built on the experiences and contributions of many people. Mr. Humphrey only describes work that he was personally involved in and he names many of the key contributors. However, so many people have been involved in this work that a full list of the important participants would be impractical.     

基于复小波噪声方差显著修正的SAR图像去噪

提出了一种基于复小波域统计建模与噪声方差估计显著性修正相结合的合成孔径雷达(Synthetic Aperture Radar,SAR)图像斑点噪声滤波方法。该方法首先通过对数变换将乘性噪声模型转化为加性噪声模型,然后对变换后的图像进行双树复小波变换(Dualtree Complex Wavelet Transform,DCWT),并对复数小波系数的统计分布进行建模。在此先验分布的基础上,通过运用贝叶斯估计方法从含噪系数中恢复原始系数,达到滤除噪声的目的。实验结果表明该方法在去除噪声的同时保留了图像的细节信息,取得了很好的降噪效果。     

How do children do mathematics with LOGO?

Abstract  This paper considers some results of a study designed to investigate the kinds of mathematical activity undertaken by children (aged between 8 and 11) as they learned to program in LOGO. A model of learning modes is proposed, which attempts to describe the ways in which children used and acquired understanding of the programming/mathematical concepts involved. The remainder of the paper is concerned with discussing the validity and limitations of the model, and its implications for further research and curriculum development.