基于IPC控制系统的实时高精度测频方法

针对IPC控制系统中流量计高精度的实时测频问题,分析了PCI-1712L和KPCI-714的测频原理和实际测试结果;通过PLC高速计数功能完成了对流量计的测频,实现了实时流量的高精度测量;利用平均值滤波算法修正了误差,使得精度进一步提高。该方法测到的频率精度达到0.4%,采集速度为20次/秒。     

基于DSP的高精度智能涡轮流量传感器设计

野外特种车辆的制冷管道流量不仅要求测量准确无误,且使用环境恶劣,对流量传感器的性能要求严格。设计一种基于数字信号处理器(DSP)的高精度智能流量传感器,使用涡轮式结构,采用DSP TMS320F2812作为核心处理器,利用高精度测频技术和温度补偿技术提高测量精度,并将测量结果通过控制器局域网(CAN)总线输出。在测量范围为3～9 m3/h条件下,测试智能涡轮流量传感器的测量误差估计效果,经实验测试结果表明:智能涡轮流量传感器的测量精度较高,测量精度为0. 3%,满足野外特种车辆的使用需求。     

TMS320F2812在电力系统测频装置中的应用

提出了一种基于数字信号处理器器(DSP)的测频方法,用于测量电网频率.与传统的单片机、PLC测频装置相比,其硬件电路简单而且测频精度较高,为测频装置的设计和实现带来了方便.为提高测频装置的实时性,还采取了修改DSP的事件管理器FIFO参数的方法,使测得的电网频率具有更好的实时性.     

基于DSP2812的全新数字锁相环

鉴于能量回馈控制系统要求回馈电流与电网电压严格同频同相,结合锁相环原理,提出了一种基于DSP TMS320F2812的高精度数字锁相控制方案.利用DSP内部的捕获单元、通用定时器和比较单元,方便地实现了对电网电压和回馈电流的信号捕获,从而达到调频调相的目的,达到并网条件.实验表明,此方法精度高,锁相速度快,保证了并网系...     

用6805实现宽范围高精度频率测量

采用ＭＣ６８０５系列单片机并充分利用其定时器，选择测频法或测周法，可以实现定范围、高精度频率测量。此种方法只占用１个内部定时器，节省了硬件开销。     

高精度测频方法及其在四频激光陀螺中的应用

为了减小普通电子计数法测频时的±1量化误差,采用数字滤波来滤除量化噪声,设计了一种高精度测频电路.使用现场可编程逻辑阵列(FPGA)器件和VHDL语言设计了测频系统,对信号发生器所产生的标准信号的测量结果表明快速滤波基本消除了量化误差的影响,实现了高速、高精度测频.该方法具有等间隔测量的特点,已用于四频激光陀螺的测试研究.     

涡街流量传感器信号处理方法研究

设计一种基于变增益运算放大器和DSP数字信号处理单元的新型涡街流量计信号处理电路.利用DSP上集成的模拟数字转换电路(A/D)实时检测涡街流量计传感器输出信号的幅度和频率,采用数字模拟转换电路(D/A)对变增益运放进行控制,控制传感器输出信号幅度的相对稳定.针对涡街流量计输出信号的频率特性,设计基于DSP的FIR滤波算法,实现输出信号噪声的初步抑制,削弱原始信号中强噪声干扰.滤波后信号由DSP进行频率信息的精确计算以及流量的解算.实验结果表明,变增益运算放大电路有效解决了涡街流量计传感器输出信号幅度变化范围大而造成的放大电路复杂,分段放大信号幅度不连续等问题;采用DSP进行数字滤波及频率计算,实现了信号中噪声的抑制以及高精度流量解算.     

基于TMS320F2812的数字频率计的设计

频率测量技术在现代科学与技术领域扮演着非常重要的角色,因此高精度、宽范围的数字频率计成为重要的测量仪器。本设计采用多周期测量原理,即用标准频率信号填充整数周期的被测信号,消除了对被测信号计数时产生的±1 Hz的计数误差,其测量精度仅与门控时间和标准频率有关;同时选用TMS320F2812DSP作为核心处理单元,利用其内部的定时器和捕获单元并结合外部的D触发器实现了频率的测量。     

双圈同轴式光纤涡轮流量计的智能化设计

为了克服现有电磁式涡轮流量计的量程小,易受电磁干扰的缺点,本文设计了一种双圈同轴式光纤的涡轮流量智能检测系统。该测试系统由三大模块组成,双圈同轴式的光纤传感器作为信号拾取工具,硬件电路对信号进行预处理,TMS320F2812 DSP对信号进一步软件处理。经过实验验证,该测试系统在5-300Hz的测量范围内,测量误差小于0.5%。因此,该测试系统具有较高的测量精度和可靠性,这为光纤涡轮流量计的样机制作提供了重要依据。     

基于DSP的高精度电量测量系统的设计

设计并实现了一种基于DSP芯片的高精度的电量测量系统,主要包括模数(A/D)转换电路和DSP处理器部分.本系统利用加Blackman-harris窗插值修正快速傅立叶变换(FFT)对异步顺序采样来的信号进行处理分析,弥补了直接利用FFT存在的误差,提高了计算精度.并且利用三次样条插值函数大大提高了加Blackman-harris窗插值FFT算法的计算速度,较好地解决了计算精度高与计算速度慢的矛盾.该系统通用性好,可靠性高,实时性强,可以实现快速、高精度的测量.     

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.