不平衡数据的无监督特征选择方法

传统特征选择方法大部分是以分布均衡的数据为研究对象,以优化总体分类精度为基本目标,所以很少有方法在不平衡数据集上得到理想的学习效果.依据数据的分布特点,提出一种新的面向不平衡数据集的特征选择方法.该方法在无监督环境下,依据聚类簇大小的变化以通过在不同簇的相同特征上对其特征重要性度量函数分配不同的权重来调整数据分布的不均衡性.在多个UCI不平衡数据集上的实验结果表明,相比于其它几种经典的特征选择方法,所提出的方法在不降低总体分类精度的情况下,不仅可以有效选择更少的特征数目,而且还可以提高少数类在不同分类器上的分类精度、召回率及F-Measure值.     

基于邻域混合抽样和动态集成的不平衡数据分类方法

不平衡数据严重影响了传统分类算法的性能,导致少数类的识别率降低。提出一种基于邻域特征的混合抽样技术,该技术根据样本邻域中的类别分布特征来确定采样权重,进而采用混合抽样的方法来获得平衡的数据集;然后采用一种基于局部置信度的动态集成方法,通过分类学习生成基分类器,对于每个检验的样本,根据局部分类精度动态地选择最优的基分类器进行组合。通过UCI标准数据集上的实验表明,该方法能够同时提高不平衡数据中少数类和多数类的分类精度。     

针对不平衡数据集的Bagging改进算法

传统的Bagging分类方法对不平衡数据集进行分类时,虽然能够达到很高的分类精度,但是对其中少数类的分类准确率不高。为提高其对少数类数据的分类精度,利用SMOTE算法对样例集中的少数类样例进行加工,在Bagging算法中根据类值对各个样例的权重进行调整。混淆矩阵和ROC曲线表明改进算法达到了既能保证整体的分类准确率,又能提高少数类分类精度的目的。     

一种鲁棒非平衡极速学习机算法

极速学习机（ELM）算法只对平衡数据集分类较好,对于非平衡数据集,它通常偏向多数样本类,对于少数样本类性能较低。针对这一问题,提出了一种处理不平衡数据集分类的ELM模型（ELM-CIL）,该模型按照代价敏感学习的原则为少数类样本赋予较大的惩罚系数,并引入模糊隶属度值减小了外围噪声点的影响。实验表明,提出的方法不仅对提高不平衡数据集中少数类的分类精度效果较明显,而且提高了对噪声的鲁棒性。     

融合特征边界信息的不平衡数据过采样方法

针对实际应用中存在的数据集分布不平衡的问题，提出一种融合特征边界数据信息的过采样方法。去除数据集中的噪声点，基于少数类样本点的多类近邻集合，融合特征边界的几何分布信息获得有利于定义最优非线性分类边界的少数类样本点，通过其与所属类簇的结合生成新样本。对不平衡数据集采用多种过采样技术处理后，利用支持向量机进行分类，对比实验表明所提方法有效改善了不平衡数据的分类精度，验证了算法的有效性。     

一种改进的降噪自编码神经网络不平衡数据分类算法

针对少数类样本合成过采样技术(Synthetic Minority Over-Sampling Technique, SMOTE)在合成少数类新样本时会带来噪音问题,提出了一种改进降噪自编码神经网络不平衡数据分类算法(SMOTE-SDAE)。该算法首先通过SMOTE方法合成少数类新样本以均衡原始数据集,考虑到合成样本过程中会产生噪音的影响,利用降噪自编码神经网络算法的逐层无监督降噪学习和有监督微调过程,有效实现对过采样数据集的降噪处理与数据分类。在UCI不平衡数据集上实验结果表明,相比传统SVM算法,该算法显著提高了不平衡数据集中少数类的分类精度。     

一种适合不平衡数据集的新型提升算法

提出了一种新的适用于不平衡数据集的Adaboost算法（ILAdaboost）,该算法利用每一轮学习到的基分类器对原始数据集进行测试评估,并根据评估结果将原始数据集分成四个子集,然后在四个子集中重新采样形成平衡的数据集供下一轮基分类器学习,由于抽样过程中更加倾向于少数类和分错的多数类,故合成分类器的分界面会偏离少数类。该算法在UCI的10个典型不平衡数据集上进行实验,在保证多数类分类精度的同时提高了少数类的分类精度以及GMA。     

一种基于聚类融合欠抽样的不平衡数据分类方法

在面对现实中广泛存在的不平衡数据分类问题时,大多数 传统分类算法假定数据集类分布是平衡的,分类结果偏向多数类,效果不理想。为此,提出了一种基于聚类融合欠抽样的改进AdaBoost分类算法。该算法首先进行聚类融合,根据样本权值从每个簇中抽取一定比例的多数类和全部的少数类组成平衡数据集。使用AdaBoost算法框架,对多数类和少数类的错分类给予不同的权重调整,选择性地集成分类效果较好的几个基分类器。实验结果表明,该算法在处理不平衡数据分类上具有一定的优势。     

基于不平衡类数据集分类的空间插值方法

对于不平衡类数据集的分类问题,训练分类器后,分类结果产生了向多数类偏斜的问题,少数类识别率较低.为了提高少数类的分类精度,提出了一种改进的SMOTE方法—空间插值方法,利用少数类及其k近邻构造超几何体,在超几何体内随机产生虚拟少数类样本,当其k近邻中存在多数类时,缩小构造虚拟样本的空间,加强对易错分样本的训练,降低数据集类不平衡程度,并进行有效性验证.在实际数据集上,基于多个分类器进行仿真,结果表明,空间插值法在少数类和数据集整体分类性能优化效果较好.     

基于DPC聚类重采样结合ELM的不平衡数据分类算法

采样技术与ELM分类算法进行结合可提高少数类样本的分类精度,但现有的大多数结合ELM的采样方法并未考虑到样本的不平衡程度及样本内部的分布情况,采样技术过于单一,导致分类模型的效率低下,少数类样本的识别率不高。针对此问题,提出了一种基于DPC聚类的重采样技术结合ELM的不平衡数据分类算法,首先根据数据集的不平衡程度分2种情况构建一个混合采样模型来平衡数据集;然后在此模型上运用DPC聚类算法分别对多数类样本和少数类样本进行分析处理,解决数据中存在的类内不平衡和噪声问题,使得2类样本相对均衡;最后使用ELM分类算法对得到的数据集进行分类。实验结果表明,与同类型分类算法进行比较,所提算法的2个分类性能指标在实验数据集上都有明显提升。     

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.