声探测网络延时概率多假设跟踪算法

针对利用同步固定声探测网络中的纯方位角延时量测数据对低空机动目标进行探测与跟踪的问题,为提高跟踪精度,根据期望最大化算法提出一种延时概率多假设目标跟踪算法,对网络中多个时刻各个传感器数据间的组合进行延时概率多假设建模,形成多假设联合量测,利用内嵌合适的贝叶斯平滑器对目标状态进行递归优化,最终得到目标状态的极大后验估计值.仿真结果表明算法能够有效解决声探测网络延时数据难以利用的问题,对低空机动目标的状态进行有效跟踪,满足估计精度要求,收敛速度快,鲁棒性强的特点.     

不完全量测下的水下纯方位系统目标跟踪算法

针对观测器探测概率小于1的不完全量测情况下的水下纯方位系统的目标跟踪问题,提出了不完全量测下的基于扩展卡尔曼滤波的目标跟踪算法。首先,建立不完全量测情况下的水下纯方位目标跟踪数学模型;其次,在数据出现不完全量测时,采用前一次的更新值对缺失数据进行弥补并完成滤波;最后,采用最优理论性能下界(CRLB)和均方根误差(RMSE)这两种评价准则对此算法进行评估。仿真实验结果表明:在不完全量测下的水下纯方位系统的目标跟踪问题中,所提出的基于扩展卡尔曼滤波的目标跟踪算法在保证预期跟踪精度的前提下,具有较高的实时性。     

量测不确定下多传感器自适应粒子滤波算法

针对量测不确定条件下多传感器量测数据的有效利用问题,提出一种多传感器自适应粒子滤波算法.利用随机采样策略和量测模型转移概率实现当前时刻多传感器量测集合的采样,通过粒子滤波中重采样步骤完成估计状态和量测集合的更新,进而依据重采样后单个传感器量测数目在传感器量测集合中的比重实现当前时刻传感器量测的确认.该算法通过有效量测的合理选择,改善了扰动对滤波精度和计算量的不利影响.理论分析和仿真实验均验证了所提出算法的有效性.     

基于GLMB滤波和Gibbs采样的多扩展目标有限混合建模与跟踪算法

本文针对杂波条件下多扩展目标的状态估计, 目标个数估计, 扩展目标形状估计问题, 提出了一种基于标签随机有限集(Labelled random finite sets, L-RFS)框架下多扩展目标跟踪学习算法, 该学习算法主要包括两方面:多扩展目标动态建模和多扩展目标的跟踪估计.首先, 结合广义标签多伯努利滤波器(Generalized labelled multi-Bernoulli, GLMB)建立了扩展目标的量测有限混合模型(Finite mixture models, FMM), 利用Gibbs采样和贝叶斯信息准则(Bayesian information criterion, BIC)准则推导出有限混合模型的参数来对多扩展目标形状进行学习, 然后采用等效量测方法来替代扩展目标产生的量测, 对扩展目标形状采用椭圆逼近建模, 实现扩展目标形状与状态的估计.仿真实验表明本文所给的方法能够有效跟踪多扩展目标, 并且在目标个数估计方面优于CBMeMBer算法.此外, 与标签多伯努利滤波(LMB)计算比较表明: GLMB和LMB算法滤波估计精度接近, 二者精度高于CBMeMBer算法.     

基于IMM多传感器顺序粒子滤波跟踪机动目标算法

针对交互式多模型粒子滤波在跟踪机动目标时精度受限问题,提出一种基于交互式多模型(IMM)的多传感器顺序粒子滤波算法。采用IMM机制实现目标运动模式的确认;在合理利用单传感器量测和多传感器量测中冗余和互补信息的基础上,引入顺序重抽样方法改善粒子分布,并将改善后的粒子应用于IMM粒子滤波算法框架。仿真实验结果表明:新算法能够估计出强机动目标状态,且精度明显优于标准IMM粒子滤波算法。     

基于Mean Shift迭代的新生未知多扩展目标跟踪

针对当前基于随机集的多扩展目标跟踪算法存在计算量大、量测划分不准确和跟踪误差大的问题,在PHD滤波基础上提出一种基于均值漂移(Mean Shift)迭代的新生未知多扩展目标跟踪算法.首先,对聚类后量测数据进行关联,得到新生目标状态,解决目标新生问题;然后,通过Mean Shift迭代获得目标量测集质心,将扩展目标的多量测问题转化为点量测处理;最后,给出其粒子实现方式.仿真实验表明,所提出的算法可以降低跟踪复杂度,提高跟踪效率,在交叉时刻具有稳定的跟踪性能。     

具有形状信息的多传感器群目标跟踪算法

针对多传感器环境下具有形状信息的扩展/群目标跟踪问题,提出了两种融合算法,即高斯逆韦氏并行PHD滤波算法和高斯逆韦氏序贯PHD滤波算法。新算法分别结合并行滤波和序贯滤波算法思想,能够对扩展/群目标的质心状态进行跟踪,对形状进行有效估计。高斯逆韦氏并行PHD滤波算法将各个传感器产生的量测集合并到一个量测集中,统一对量测集进行划分。在滤波更新阶段,对划分后的量测集进行扩维,从而在形式上将多传感器环境下的跟踪问题转化为单传感器环境下的跟踪问题。高斯逆韦氏序贯PHD滤波算法则先对各个传感器产生的量测集依次进行划分,再依次对每一个划分后的量测集进行滤波,从而达到融合多个传感器量测的目的。仿真结果表明该算法的可行性和有效性。     

基于交互式CPHD的多传感器多机动目标跟踪

针对多传感器高速多机动目标的跟踪问题,提出一种多传感器交互式贪婪势概率假设密度(MS-IMMGreedy-CPHD)滤波器.该滤波器在预测阶段,通过交互式多模(IMM)算法对势概率假设密度(CPHD)滤波中目标的状态、势分布和运动模型同时进行预测;在滤波的更新阶段,利用贪婪(greedy)量测划分机制选取多传感器量测子集和拟分区,并通过拟分区量测子集对不同模型下CPHD预测的目标状态和势分布以及模型进行交互式更新.仿真结果表明,所提出MS-IMM-Greedy-CPHD滤波能够对高机动多目标进行稳定有效的跟踪,相较于多传感器势概率假设密度(MS-CPHD)滤波,跟踪结果的OSPA误差更小且势估计更加准确.     

稀疏高斯厄米特PHD机动多目标跟踪算法

针对基于概率假设密度（probability hypothesis density，PHD）的非线性机动多目标跟踪精度低、滤波发散、目标数目估计不准确等问题，提出一种基于交互式多模型的稀疏高斯厄米特PHD算法.该算法在PHD滤波器下，采用稀疏高斯厄米特方法对目标进行状态预测和量测更新，构造一种稀疏高斯厄米特PHD滤波器；然后将交互式多模型算法融入稀疏高斯厄米特PHD滤波框架中，解决了目标机动过程中运动模式不确定的问题.仿真结果表明该算法能对机动多目标进行有效的跟踪，相比交互式多模型不敏卡尔曼PHD等滤波方法具有更高的状态估计精度，且目标数目估计更准确.     

基于IMM-PF的分布式估计融合算法

针对基于扩展卡尔曼滤波的估计融合算法存在线性化误差,且受高斯噪声假设限制的问题,提出一种基于交互式多模型粒子滤波(IMM-PF)的分布式多传感器估计融合算法.各传感器节点采用IMM-PF算法,以便在非线性、非高斯条件下稳健地跟踪机动目标;融合中心则采用基于粒子滤波(PF)的分布式融合方法进行全局估计融合.该算法适用于非线性、非高斯条件下的多传感器状态估计.仿真结果表明,该算法能够提高多传感器系统状态估计的精度.     

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.