基于空谱初始化的非负矩阵光谱混合像元盲分解

混合像元分解是提高遥感监测能力的有效方法之一,因此一直以来是遥感领域的重要研究内容。非负矩阵盲分解(Non-negative Matrix Factorization,NMF)方法无需监督选择端元,无需假定纯像元存在,且能同步获取优化的端元光谱与端元丰度,从而为先验知识不足、高度混合场景下的混合像元分解提供了不错的选择,因此成为高光谱混合像元分解方法的重要分支之一。但NMF易陷入局部最优,若直接应用于混合像元解混难以获取稳定的最优解,从而影响了NMF在光谱混合分解的推广应用。针对这一问题,提出一种利用空谱预处理(SSPP)改进NMF的混合像元分解方法(SSPP-NMF)。首先利用SSPP算法结合空间和光谱信息筛选出合理有效的数据子集;然后用NMF算法对筛选出的数据子集进行混合像元分解,获取具有空间均匀性和光谱纯净性的端元光谱;最后基于上一步获取端元光谱利用非负最小二乘法(NNLS)获取整个研究区的最终端元丰度。为检验该方法的有效性和适用性,分别采用模拟仿真数据和真实遥感影像分析了SSPP对NMF的改善效果,并与ATGP-NMF、MVC-NMF两种基于初始化改进NMF的方法进行了比较分析,结果表明:相比ATGP-NMF、MVC-NMF而言,SSPP算法更能有效抑制噪声的影响,明显地提高NMF分解效果,并且具有较高的时间效率。     

基于Hessian图正则稀疏NMF的高光谱解混

基于非负矩阵分解(Nonnegative Matrix Factorization, NMF)的高光谱解混(Hyperspectral Unmixing,HU)方法引起了大家的关注,因为可以将一个非负高光谱图像(Hyperspectral Imagery, HSI)数据矩阵分解为两个非负矩阵的乘积,分别对应于端元矩阵和丰度系数矩阵。目前,图约束的NMF算法已经被证明对高光谱解混是有效的,因为它们可以捕获HSI的几何特性。为了挖掘数据在混合过程中的几何结构和稀疏性,提出了一种稀疏的Hessian图正则化NMF(SHGNMF)算法。SHGNMF算法是将丰度矩阵的L1/2正则化器和Hessian图正则化项都添加到每个NMF模型中,同时采用乘法更新规则。最后用模拟数据和真实数据进行实验,验证了所提出的SHGNMF算法相对于其他NMF算法的优越性。     

基于图正则化和稀疏约束的增量型非负矩阵分解

非负矩阵分解(Nonnegative Matrix Factorization,NMF)不仅可以很好地描述数据而且分解后的矩阵具有直观的物理意义。为了提高算法的有效性和识别率,提出了一种更为合理的算法——基于图正则化和稀疏约束的增量型非负矩阵分解(Graph Regularized and Incremental Nonnegative Matrix Factorization with Sparseness Constraints,GINMFSC)。该算法既保持了数据的几何结构,又充分利用上一步的分解结果进行增量学习,而且对系数矩阵施加了稀疏性约束,最后将它们整合于单个目标函数中,构造了一个有效的更新算法。在多个数据库上的仿真结果表明,相对于NMF,GNMF,INMF,IGNMF等算法,GINMFSC算法在降低运算时间的同时,还具有更好的聚类精度和稀疏性。     

基于樽海鞘群体优化非负矩阵分解的高光谱图像解混算法

针对鲁棒非负矩阵分解应用于高光谱图像处理时,存在对初始值的敏感性,求解目标函数时易陷入局部最优的缺点,提出基于樽海鞘群体优化鲁棒非负矩阵分解的高光谱图像解混算法.该算法基于鲁棒线性混合模型,在RNMF框架下,采用樽海鞘群体算法取代乘法迭代策略,以增强算法全局搜索能力,在约束空间内随机搜索满足目标函数的全局最优解,可有效地完成非线性高光谱图像解混.仿真数据与真实遥感数据实验结果表明,本文算法在处理高光谱图像时,能够有效地避免RNMF算法易陷入局部最优解的局限性,具有更好的解混性能.     

基于拉格朗日的高光谱解混算法研究*

针对混合像元分解误差问题,提出一种基于拉格朗日算法的高光谱解混算法。通过变分增广拉格朗日算法提取出部分端元,由于端元组中存在相似端元影响解混精度,利用基于梯度的光谱信息散度算法进行光谱区分,除去相似端元。通过对得到的端元进行排序,依次增加端元进行光谱解混,将满足条件的端元增加进端元组,最终得到优选端元。该方法不仅有效去除了相似端元的干扰,而且不需要不断搜索端元的组合,根据每个端元对于混合像元的重要性做出相应次数的非限制性最小二乘法计算,得到更精确高光谱端元的子集,该方法对高光谱混合像元解混的效率以及可靠性均有所提高。     

基于稀疏约束的半监督非负矩阵分解算法

矩阵分解因可以实现大规模数据处理而具有十分广泛的应用。非负矩阵分解(Nonnegative Matrix Factorization,NMF)是一种在约束矩阵元素为非负的条件下进行的分解方法。利用少量已知样本的标注信息和大量未标注样本,并施加稀疏性约束,构造了一种新的算法——基于稀疏约束的半监督非负矩阵分解算法。推导了其有效的更新算法,并证明了该算法的收敛性。在常见的人脸数据库上进行了验证,实验结果表明CNMFS算法相对于NMF和CNMF等算法具有较好的稀疏性和聚类精度。     

利用稳健非负矩阵分解实现无监督高光谱解混

目的 基于非负矩阵分解的高光谱图像无监督解混算法普遍存在着目标函数对噪声敏感、在低信噪比条件下端元提取和丰度估计性能不佳的缺点。因此,提出一种基于稳健非负矩阵分解的高光谱图像混合像元分解算法。方法 首先在传统基于非负矩阵分解的解混算法基础上,对目标函数加以改进,用更加稳健的L₁范数作为重建误差项,提高算法对噪声的适应能力,得到新的无监督解混目标函数。针对新目标函数的非凸特性,利用梯度下降法对端元矩阵和丰度矩阵交替迭代求解,进而完成优化求解,得到端元和丰度估计值。结果 分别利用模拟和真实高光谱数据,对算法性能进行定性和定量分析。在模拟数据集中,将本文算法与具有代表性的5种无监督解混算法进行比较,相比于对比算法中最优者,本文算法在典型信噪比20 dB下,光谱角距离（spectral angle distance,SAD）增大了10.5%,信号重构误差（signal to reconstruction error,SRE）减小了9.3%;在真实数据集中,利用光谱库中的地物光谱特征验证本文算法端元提取质量,并利用真实地物分布定性分析丰度估计结果。结论 提出的基于稳健非负矩阵分解的高光谱无监督解混算法,在低信噪比条件下,能够获得较好的端元提取和丰度估计精度,解混效果更好。     

基于稀疏和正交约束非负矩阵分解的高光谱解混

针对基于非负矩阵分解（NMF）的高光谱解混存在的容易陷入局部极小值和受初始值影响较大的问题，提出一种稀疏和正交约束相结合的NMF的线性解混算法SONMF。首先，从传统的基于NMF的高光谱线性解混方法出发，分析高光谱数据本身的理化特性；然后，结合丰度的稀疏性和端元的独立性两个方面，将稀疏非负矩阵分解（SNMF）和正交非负矩阵分解（ONMF）两种方法结合应用到高光谱解混当中。模拟数据和真实数据实验表明，相比顶点成分分析法（VCA）、SNMF和ONMF这三种参考解混算法，所提算法提高了线性解混的性能；其中，评价指标光谱角距离（SAD）降低了0.012~0.145。SONMF能够结合两种约束条件的优势，弥补传统基于NMF线性解混方法对高光谱数据表达的不足，取得较好的效果。     

基于非负矩阵分解的图像水印算法

提出一种基于非负矩阵分解NMF(Non-negative Matrix Factorization)的数字水印算法.先通过NMF构造载体图像基于部分表示的系数矩阵,将灰度水印图像嵌入其中;再利用NMF基矩阵作为密钥提取水印.为了说明有效性,该算法与主流的DCT水印算法进行相关比较实验,结果表明该算法同DCT算法一样有效,且在抗剪切和抗滤波性能上优于DCT算法.     

基于双线性型的非负矩阵集分解

非负矩阵分解(Non-negative Matrix Factorization,NMF)是一种常用的非负多元数据描述方法.处理数据矩阵集时,NMF描述力不强、推广性差.为解决这两个问题,并保留NMF的好特性,该文提出了非负矩阵集分解(Non-negative Matrix Set Factorization,NMSF)的概念,并在NMSF的框架下系统研究了基于双线性型的非负矩阵集分解(Bilinear Form-Based Non-negative Matrix Set Faetorization,BFBNMSF),构造了单调下降的BFBNMSF算法.理论分析和实验结果均表明:处理数据矩阵集时,BFBNMSF比NMF描述力强、推广性好.由此可认为,此时BFBNMSF比NMF更善于抓住数据的本质特征.     

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。     

煤矿井下安全监控分站的设计及其仿真实现

为了设计一种具有低成本、低功耗、易操作、功能强且可靠性高的煤矿井下安全分站,针对煤矿安全生产实际,文章提出了采用MCS-51系列单片机为核心、具有CAN总线通信接口的煤矿井下安全监控分站的设计方案;首先给出煤矿井下安全监控分站的整体构架设计,然后着重阐述模拟量输入信号处理系统的设计过程,最后说明单片机最小系统及其键盘、显示、报警、通信等各个组成部分的设计;为验证设计方案的可行性与有效性,使用Proteus软件对设计内容进行仿真验证,设计的煤矿井下安全监控分站具有瓦斯、温度等模拟量参数超标报警功能和电机开停、风门开闭等开关量指示功能;仿真结果表明:设计的煤矿井下安全监控分站具有一定的实际应用价值.     

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.     

View-based model-driven architecture for enhancing maintainability of data access services

In modern service-oriented architectures, database access is done by a special type of services, the so-called data access services (DAS). Though, particularly in data-intensive applications, using and developing DAS are very common today, the link between the DAS and their implementation, e.g. a layer of data access objects (DAOs) encapsulating the database queries, still is not sufficiently elaborated, yet. As a result, as the number of DAS grows, finding the desired DAS for reuse and/or associated documentation can become an impossible task. In this paper we focus on bridging this gap between the DAS and their implementation by presenting a view-based, model-driven data access architecture (VMDA) managing models of the DAS, DAOs and database queries in a queryable manner. Our models support tailored views of different stakeholders and are scalable with all types of DAS implementations. In this paper we show that our view-based and model driven architecture approach can enhance software development productivity and maintainability by improving DAS documentation. Moreover, our VMDA opens a wide range of applications such as evaluating DAS usage for DAS performance optimization. Furthermore, we provide tool support and illustrate the applicability of our VMDA in a large-scale case study. Finally, we quantitatively prove that our approach performs with acceptable response times.     

A pragmatic multi-method investigation of discrepant technological events: Coping,attributions, and ‘accidental’ learning

Discrepant technological events or situations that entail a problem, a misunderstanding or a difficulty with the Information Technology (IT) being employed, are common in the workplace, and can lead to frustration and avoidance behaviors. Little is known, however, about how individuals cope with these events. This paper examines these events by using a multi-method pragmatic approach informed by coping theory. The results of two studies – a critical incident study and an experiment – serve to build and test, respectively, a theoretical model that posits that individuals use a variety of strategies when dealing with these events: they experience negative emotions, make external attributions, and adopt engagement coping strategies directed at solving the event, eventually switching to a disengagement coping strategy when they feel they have no control over the situation. Furthermore, users’ efforts may result in ‘accidental’ learning as they try to overcome the discrepant IT events through engagement coping. The paper ends with a discussion of the results in light of existing literature, future opportunities for research, and implications for practice.