一种基于16位单片机的三相电参数测量技术及实现

论述了一种用于测量三相电功率、功率因数、相电压、相电流的测量技术,并论述了基于u'nSP16位单片机的实现方法.三相电测量采用交流采样技术,软件算法采用快速傅里叶变换FFT,全面克服了以前的三相电参数测量方法普遍存在的实现电路复杂以及在功能和精度上的不足.     

电力参数的微机交流采样技术

以80C196KB单片机为核心,介绍了一种实现电力参数交流采样技术的基本算法,并对其硬件测量电路进行了详细的阐述。采用该交流采样算法和具体硬件电路设计了高低压配电间监测系统,现场运行结果表明,系统运行情况良好,各项参数的测量精度均达到了预期的设计要求。     

三相电气参量快速和高精度的测量算法

提出了一种快速富里叶变换FFT算法来测量电力系统基波频率和其它谐波频率的实时值,进而计算出三相电压和电流的有效值与相位的实际值。由于电力系统参数随时都在变化,非正弦信号的系统基波频率不可能是一个确定的值,采用未确定的系统基波频率来采样和测量非正弦信号变化的三相电压和电流将引起很大的误差。因此,提出先准确测量非正弦信号的系统基波频率,然后,采用准确的系统基波频率来采样三相电压和电流,进而再计算三相电压和电流的有效值与相位的实际值、有功功率与电能、无功功率与电能等。这种算法不仅大大缩短计算时间,而且提高了测量的精度,测量精度可以达到0.1%或更高。实例计算的仿真结果及实际应用系统的运行数据都证明:这种算法的可靠性、准确性和快速性。     

数字传感器信号采样技术研究

为了提高数字传感器输出信号的采样精度,简化采样处理,提出了一种将脉冲宽度测量和脉冲计数测量相结合的复合采样方法,给出了该方法的基本原理,并依据信号采样理论,推导了该方法的基本计算公式,讨论了它的采样精度、性能和参数选取限制.结合实际应用情况,给出了可以节省处理量的基于整数运算的改进算法和可以使采样精度最大化的动态精度自适应算法.该方法已成功地应用到实际系统中,实测数据表明,该方法有较好的精度和适应性.     

时频参数测量中存储容量的压缩方法

介绍一种单片机测量时频参数时的数据处理方法,即线性地址变换法。在存储容量有效压缩的基础上,进一步分析采样数据,用软件实现可控时标,保证测量精度。     

自相关锁定放大器的实现方法

研究了一种基于自相关运算的数字锁定放大器算法，讨论了该该算法的测量精度和采样频率等参数。仿真试验表明本文中的算法可用于当同频率参考信号不能获得时，低信噪比条件下正弦信号的幅度的测量。     

单片机在等精度测频中的应用

单片机在等精度测频中的应用ＴｈｅＡｐｐｌｉｃａｔｉｏｎｏｆＳｉｎｇｌｅ－ＣｈｉｐＭｉｃｒｏｃｏｍｐｕｔｅｒｉｎＦｒｅｑｕｅｎｃｙＭｅａｓｕｒｅｍｅｎｔ●李名兆ＬｉＭｉｎｇｚｈａｏ频率检测是电子测量领域的最基本测量之一，它与许多电气参数的测量都有着十分...     

虚拟仪器下的电力参数测试

本文介绍了一种利用虚拟仪器进行电力参数测试的方法，以及在电力参数测试中，采用交流采样、同时采样、跟踪采样等技术以克服传统采样方法带来的测量误差，从而提高测量精度。     

交流同步采样在断路器测控装置中的应用

真空断路器遥测装置中最重要的测量参数中最重要的是三相交流电参数,当电网频率波动时,必须采用交流同步采样技术才能保证采样计算精度,同步检测和FFT算法成为其核心技术,文章提出了如何使用硬件同步和软件同步相结合,以提高三相同步交流采样的精度和可靠性。     

钻杆加厚端内轮廓参数快速提取算法

为了快速求取钻杆加厚端内轮廓参数,提出了一种新的算法.依据该视觉测量系统采样数据的特点,新的算法主要分为母线重采样、母线差分、落差法分区、线性回归等几个步骤.实验结果表明,新的算法能够快速地提取出钻杆加厚端内轮廓参数,并获得较高的精度和良好的稳定性.对于粗糙工件,直径方向的重复性精度小于0.1 mm,轴向重复性精度达到0.6 mm.     

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.