基于“前照法”的LAMOST光纤位置提取

LAMOST（大天区面积多目标光纤光谱天文望远镜）的整个系统对光纤定位单元的定位精度要求较高，为了使LAMOST可以精确对准天体目标，需要有一套光纤定位单元的位置检测装置可以高精度、高效地在大尺度范围内同时对数千个光纤位置目标进行精确检测。主要研究“前端照明图像处理方法”的光纤位置检测，通过对图像的预处理，采用基于半径的霍夫空间转换和最小二乘法拟合圆心的图像处理算法获取光纤的像素坐标，相比于传统的前端照明的图像算法提取像素位置，显著提高光纤位置像素坐标的检测精度和准确性，减少干扰光斑的影响，并通过实际拍摄验证前照法的稳定性，可以满足LAMOST的使用要求。     

基于CAM的LAMOST光纤单元结构误差仿真分析

LAMOST天文望远镜要求直径1.75 m球冠状焦面板上的4000个光纤定位单元能够快速准确地对准4000个星体目标进行观察,其定位精度要求高.但单元偏心轴处齿轮啮合传动、轴与轴承存在的间隙等,都会导致光纤定位发生偏离,影响光纤的精确定位.本文利用Solidworks和ADAMS对单元偏心轴处齿轮传动仿真,对轴与轴承间隙的不同大小用正交试验方法设计9组对比仿真试验.研究结果表明:偏心轴处齿轮最大窜动量在许可范围,且对单元定位精度影响不大;单元轴间隙整体误差范围在-0.06deg/sec～0.2deg/sec,可使光纤定位单元的定位精度变差甚至不能满足观测要求.以上分析研究为将来新一代高精度定位单元的设计提供一定的理论依据.     

光纤定位单元的无刷直流电机控制系统设计

大天区面积多目标光纤光谱天文望远镜(LAMOST)的改进项目计划使用一种直径为10mm的光纤定位单元替换原来的30mm光纤定位单元,以增加焦面上布置的光纤数量并达到增加光谱获取率的目的。新的10mm双回转光纤定位单元使用了两个4mm无刷直流电机和串联在单元尾部的控制板进行光纤的定位,一种紧凑的无刷直流电机位置控制系统被设计用于新的10mm单元的控制。该控制系统可同时实现两个电机的控制,并解决电机的细分、位置校正、堵转检测等问题。从硬件设计和软件设计介绍了该控制系统的搭建和定位实现。     

LAMOST小焦面系统模拟星像观测仿真与单元测试

本文主要介绍LAMOST光纤定位控制程序中的模拟星像观测仿真的实现算法,包括模拟星像产生、角度参数计算、星像分配和干涉处理等,对模拟星像进行观测仿真测试,在系统运行之前有必要验证控制程序中各种算法的可行性和合理性.单元定位是LAMOST主要关键技术之一,其定位精度是焦面系统的核心.由于各种误差的存在,某些单元的精度达不到要求,利用小焦面系统对4 000个单元进行逐批跑合测试,通过星像仿真实验完成了4 000个单元的精度跑合测试.因此,星像观测仿真对测试程序算法和测试单元精度都具有重要意义.     

光学显微定位系统定位精度分析

为了提高光学显微定位系统对细胞微生物识别定位的精度：一方面，必须改进手眼标定方法；另一方面，需要提高全局图像识别的准确性，因此，提出一种两步法对系统进行手眼标定。首先，通过标定固定靶标来确定系统原点，并得到视觉模块相对于系统原点的转换关系；然后，根据每次拍照的起始点位置、拍照的数量和移动的步长求解出全局图像相对于系统原点的转换关系；最后，为了进一步提高全局转换关系的准确度，提出一种基于傅里叶变换的误差矫正方法，利用傅里叶变换求解出视觉模块在移动过程中的误差，并加入系统进行补偿。实验结果表明，误差补偿之后，系统X轴方向的误差均值从10.23 μm降为-0.002 μm，Y轴方向的误差均值从6.9 μm降为-0.50 μm，显微定位系统的平均定位精度达到了99%以上。结果表明，所提方法可很好地用于光学显微定位系统对细胞微生物进行高精度的自动化抓取。     

基于TOA算法的UWB室内定位的定标方法

为了解决到达时间(Time of Arrival, TOA)算法中基站与待定位标签时钟不同步导致定位精度低的问题,基于差分GPS定位技术,提出了一种用于超宽带-到达时间(Ultra Wide Band-TOA,UWB-TOA)室内定位系统的时钟定标方法。在TOA定位算法的基础上,增加一个位置已知、与待定位标签时钟差固定的定标标签,通过定标测试计算待定位标签与定标标签之间固定的时钟差。将该固定时钟差补偿到TOA定位测距中,实现对待定位标签的时钟修正,不仅能提高定位效率还能提高定位精度。在MATLAB中对矩形、叉形、椭圆等轨迹的运动标签在固定时钟差、线性时钟差、非线性时钟差等多种误差下进行定位仿真实验,结果表明所提的时钟定标方法通过补偿提高TOA算法定位精度85%以上,验证了定标方法的正确性和有效性。     

基于协同再入飞行器的舰船目标定位方法研究

研究再入飞行器的舰船目标优化定位问题,由于目标是由多基站雷达协同定位,在没有景象和地形匹配条件下,飞行器存在位置误差和姿态误差,造成目标定位精度差。为最大程度发挥再入飞行器的作战效能和战斗力,提出通过对多再入飞行器的相对位置误差和姿态角度误差进行校正,来提高融合定位精度。采用扩展卡尔曼滤波方法,依托惯性导航、卫星导航及飞行器间通信测距条件下的目标融合定位方法进行仿真。仿真结果表明,在卫星导航或再入飞行大机动的通信测距条件下,可以有效提高目标定位精度,为再入飞行器优化定位提供了科学依据。     

机器人抓取视觉传感目标精确定位方法

机器人抓取目标时,准确完成任务的前提是可以精准检测到目标位置,当距离目标较远时,以信号传感为基础的定位精度和稳定性会受到影响。为解决上述问题,提出基于视觉传感器的机器人抓取目标精确定位方法。利用视觉传感器获取目标图像,并标定目标位姿。采取直线段检测方法提取目标位姿特征,将提取的特征输入到改进粒子群算法的支持向量机回归模型中,输出定位结果。利用回归误差补偿模型对定位结果补偿,完成机器人抓取目标精确定位。实验结果显示,利用视觉传感器后,机器人抓取目标的定位时间为35s、与实际位置的接近程度高于81%、置信度高于92%,由此可知机器人抓取视觉传感目标定位效果较好。     

NLOS环境下多传感器融合的室内定位方法

为提高超宽带(ultra-wideband, UWB)技术在非视距(non line of sight, NLOS)环境下的定位精度,提出一种基于粒子滤波融合视觉与UWB数据的定位方法。视觉模块通过识别与检测标签推算出绝对位姿;UWB模块鉴别由NLOS条件干扰的测距值,筛选最优测距值进行自适应权重的定位算法,提升覆盖区域的整体定位精度;基于粒子滤波将两者的实时定位信息进行数据融合。实验结果表明,融合定位方法具有实时性和鲁棒性,有效抑制了NLOS环境引起的误差,在NLOS环境下定位精度能够达到0.26 m。     

基于地图信息和位置自适应修正的粒子滤波室内定位方法

现有以航位推算为基础的室内定位算法存在累积误差大、定位精度较低等缺点,为此提出一种基于地图信息和位置自适应修正的粒子滤波室内定位方法。该方法利用已知的室内地图信息在定位过程中控制粒子的生灭,在重采样过程中根据粒子的退化情况对补偿粒子的位置进行自适应调整,从而修正目标位置。实验结果表明,该定位方法克服了航位推算算法的累积误差问题,有效提高了定位精度。     

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.