基于卡尔曼滤波预测的无偏量测转换方法

针对在目标跟踪系统中通常使用量测转换方法将球面坐标系下的量测量转换到笛卡尔坐标系下,传统量测转换方法在互距离测量误差增大时跟踪性能有所下降的问题,提出一种基于卡尔曼滤波预测的无偏量测转换方法。采用无偏量测转换方法变换量测量,基于卡尔曼滤波预测值,结合无迹变换算法估计转换量测方差。仿真结果表明,所提出的转换量测卡尔曼滤波算法较现有方法具有更高的跟踪精度和可信度。     

加权融合法处理无序量测问题

针对集中式多传感器目标跟踪系统中存在的无序量测问题,基于协方差加权融合的思想,在融合估计误差协方差矩阵迹最小意义下,建立了基于最优融合的多步延迟无序量测更新算法。该算法先将无序量测配准到最新状态估计的时刻,将其与之进行协方差加权融合。为进行无序量测与各传感器量测噪声相关性的计算,引入了等效量测。通过理论分析和仿真实验说明该算法能有效处理无序量测多延迟问题,其性能接近最优且随延迟步数增加性能下降非常小,而且有与最优的数据缓存法相同的滤波精度,以及较小的额外存储量。     

在目标航迹断续下雷达和ESM数据关联的新方法

雷达和ESM是获取敌方目标电子信息最重要的传感器,通过航迹关联、估计处理,可以提高对空域的态势感知能力.当雷达和ESM的探测目标航迹处于断续情况下,角度直接关联的不确定性很容易造成错误关联或漏关联,从而不断起始新的融合航迹.论文将测量的角度转换为证据,再利用DS理论进行频谱、属性等证据综合推理,能较好地提高关联正确率,维持融合航迹的连续性.     

毫米波/红外复合制导信息融合技术研究

研究红外复合制导问题,对于复合制导中的集中式融合,与共同的噪声环境等因素使得各传感器的量测误差之间存相关性,且相关程度未知,对得到的融合估计不是最优的.红外导引头测量存在不完全可观性,一般的分布式融合也难以实现.针对以上问题,提出了一种基于协方差交叉法的信息融合算法,在估计相关性未知时利用信息空间上的均值和协方差凸组合,通过寻找行列式的最小方差阵,融合各传感器的局部估计,可以得到不低于单个传感器估计的融合估计精度.进行量测相关数据,并通过UKF滤波仿真验证,证明算法的有效性.     

基于着陆雷达的飞机下滑航迹融合算法设计与实现

针对目前飞机进近着陆阶段部分型号着陆雷达实时提供三维位置数据时信息不完整的问题,提出了一种基于雷达坐标系的航迹融合算法,将不同源的航迹数据转换到雷达坐标系下进行航迹关联,再进行最小二乘加权卡尔曼滤波,并通过仿真验证与工程实践,证明该算法可以有效实现飞机着陆阶段的航迹融合。     

联合ADS-B的最小二乘雷达系统误差估计方法

为了解决两坐标雷达系统误差估计问题,提出一种联合ADS-B的最小二乘雷达系统误差估计方法.提出方法首先将ADS-B量测从地理坐标系转换到雷达局部直角坐标系,建立统一的配准空间;其次以雷达航迹的采样时间为基准,对ADS-B航迹进行插值,构造新的ADS-B航迹;然后采用直线拟合算法分别计算雷达航迹和ADS-B航迹的直线方程,并计算两条直线的夹角,再利用该夹角补偿雷达航迹的航向角数据;最后采用最小二乘算法估计雷达系统误差.实测数据实验结果表明,与传统直线拟合方法和最小二乘方法相比,提出方法能够更有效地估计雷达系统误差;经过提出方法配准处理后,雷达航迹数据的平均斜距离误差和方位角误差分别降低71.7%和52.7%.     

基于概率假设密度滤波的多目标雷达空间误差配准算法

针对数据关联关系不确定的多目标场景下的雷达空间误差配准问题,提出一种基于概率假设密度(PHD)滤波的雷达空间误差估计方法.该方法在地心地固(ECEF)坐标系下建立雷达空间误差及其观测的随机有限集合(RFS)描述形式,结合PHD滤波算法避免多个雷达观测的数据关联问题,利用高斯混合概率假设密度(GM-PHD)滤波器实现多目标场景下的雷达系统误差递推融合估计.Monte Carlo仿真实验结果表明,所提出的基于PHD滤波的雷达空间误差配准算法能够有效地实现数据关联关系不确定情况下的多目标雷达空间误差融合估计,且估计精度及稳定性优于结合数据关联算法的空间误差配准方法.     

空间非合作目标在轨主/被动融合跟踪方法

针对空间远距离非合作目标的点目标跟踪问题,研究基于非地面测控数据支持的远距离空间目标的在轨主/被动融合跟踪方法。包括运用基于被动传感器以及雷达间歇辅助测距跟踪的Unscented卡尔曼滤波(UKF)方法,得到非合作目标的运动状态信息,即利用光学跟踪摄像机的二维角度量测值及雷达间歇提供的距离量测值,估计目标的惯性位置与速度方法,为后续自主空间操作建立初始轨道状态数据。仿真结果表明,当状态误差和量测噪声改变时,UKF均能持续跟踪远距离非合作目标,使得雷达间歇提供的距离信息可以得到更好的跟踪精度。     

多传感器信息融合的目标跟踪研究

为了提高红外与毫米波雷达双模制导系统的目标跟踪精度,提出了将UKF用于红外和毫米波雷达的数据处理,采用分布式融合结构,通过对两传感器的滤波协方差矩阵的相关估计,将滤波协方差矩阵和状态估计进行融合。该方法应用于红外与毫米波雷达双模制导系统的目标跟踪仿真,仿真结果表明：与单传感器系统相比,该方法提高了制导系统的目标跟踪精度。     

基于近邻量测认知信息的多传感器融合估计

在构建传感器模糊量测认知偏差的基础上,提出一种新的多传感器融合估计方法。运用相邻量测样本均值和协方差度量传感器可靠性,确保融合权重分配的客观性和灵敏性。实验结果表明,与基于均值融合算法和支持度融合算法相比,使用该方法得到的融合权值分配方式更加合理,可进一步提高估计精度。     

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。     

基于QTE的蒙古文显示机制研究与实现

蒙古语言是中国蒙古族使用的通用语言,由于蒙古文区别于其他文字的书写方式和其自身变形机制等特点,在很多通用的文字处理引擎中都不被支持。在嵌入式产品开发与应用领域中Linux加QTE已经成为流行方式。该文给出了一种在QTE环境上实现基于标准Unicode的蒙古文点阵显示和变形算法, 并自定义了支持蒙古文的QTE组件,扩展了QTE功能,为在Linux加QTE方式的嵌入式体系结构中处理蒙古文提供了一种解决方法。