基于Hadoop平台的数据挖掘技术研究

Hadoop集MapReduce、HDFS、HBase、Avro、Pig等子项目于一身,并行编程模型(MapReduce)、分布式文件系统(HDFS)是Hadoop的核心技术。用户可以通过结合编程模型MapReduce与Hadoop的方式对分布式程序进行进行二次开发,从海量数据中挖掘隐含的、新颖的、对决策实施工作有指导价值的关系、模型,在Hadoop平台上构建数据挖掘系统。     

基于Hadoop MapReduce模型的应用研究

MapReduce是一种简化并行计算的分布式编程模型,是Google的一项重要技术,通常被用于数据密集型的分布式并行计算.探讨了来自Apache开源的分布式计算平台Hadoop的核心设计MapReduce编程模型,并通过算法实验分析和研究了MapReduce模型的工作方式和应用方法.     

MapReduce集群环境下的数据放置策略

MapReduce是一种适用于大规模数据密集型应用的有效编程模型,具有编程简单、易于扩展、容错性好等特点,已在并行和分布式计算领域得到了广泛且成功的应用.由于MapReduce将计算扩展到大规模的机器集群上,处理数据的合理放置成为影响MapReduce集群系统性能(包括能耗、资源利用率、通信和I/O代价、响应时间、系统的可靠性和吞吐率等)的关键因素之一.首先,对MapReduce编程模型的典型实现——Hadoop缺省的数据放置策略进行分析,并进一步讨论了MapReduce框架下,设计数据放置策略时需考虑的关键问题和衡量数据放置策略的标准;其次,对目前MapReduce集群环境下的数据放置策略优化方法的研究与进展进行了综述和分析;最后,分析和归纳了MapReduce集群环境下数据放置策略的下一步研究工作.     

Hadoop云计算平台在视频转码上的应用

视频转码是一种计算密集型和数据密集型的工作，需要消耗大量的计算机资源，Hadoop MapReduce是一种软件模型，支持大规模数据集的分布式处理．．利用已有开源视频转码软件ffmpeg建立一个基于MapReduce框架的Hadoop集群转码系统，提高视频转码的速度．     

基于MapReduce模型的并行量子进化算法

利用MapReduce模型可自动编写串行程序及编程接口简单的优点,实现量子进化算法在MapReduce模型下的并行化,提出基于MapReduce模型的并行量子进化算法MRQEA,并将其部署到Hadoop云计算平台上运行。对0-1背包问题的测试结果证明,MRQEA算法在处理大型数据集时具有良好的加速比和并行效率。     

MapReduce连接查询的I/O代价研究

数据的指数级增长给数据管理和分析带来了严峻的挑战.连接查询是数据分析中一种常用运算,而MapReduce是一种用于大规模数据集并行处理的编程模型,研究基于MapReduce的连接查询代价评估和查询优化,有着学术意义和应用价值.MapReduce连接查询算法的性能主要取决于I/O代价(包括本地和网络I/O),而I/O代价与数据集以及连接运算的特征参数相关,通过对二元连接的I/O代价评估可以优化多元连接执行计划.基于此,首先提出了二元连接查询的I/O代价模型;随后,对现有二元连接算法进行形式化定义和简单扩展,归纳出6种基于MapReduce连接查询算法,并通过算法白盒分析定义它们的I/O代价函数;最后,提出一种多元连接最优执行计划的选择算法.通过实验表明I/O代价模型的正确性且能够准确地反映算法的性能优劣.     

一种Hadoop中基于作业类别和截止时间的调度算法

Hadoop是一种开源可靠的分布式计算框架,而MapReduce是处理超大规模数据集的编程模型.鉴于Ha-doop内置的调度器不能很好地处理类别不同且有截止时间的作业的调度,提出了一种基于作业类别和截止时间的作业调度算法.作业分为CPU密集型和I/O密集型,并根据截止时间设置优先级来实现作业的调度.实验结果表明,该算法在充分利用集群的CPU和磁盘I/O的同时,能满足作业的截止期需求,当同一时间段内截止时间相近时算法达到最优,当某一队列中作业截止时间均比另一种队列短时,算法效率最低.     

基于MapReduce的多路连接优化方法研究

MapReduce是Google开发的一种并行分布式计算模型,已在搜索和处理海量数据领域得到了广泛的应用。但是MapReduce框架中的"一对一分区"策略使得其在处理多数据连接任务时,需要将该任务拆分成多个链接的子任务,造成中间结果集的频繁"洗牌",带来巨大的磁盘I/O开销。文中就该问题提出了一种新的分区策略:"一对多分区"策略,为了能够在MapReduce框架中实现这一分区策略,因此需要对MapReduce框架中的分区函数接口进行修改。改进策略的优点在于只要一个MapReduce任务就能够完成多数据集连接任务,因此节省了I/O开销。最后在搭建的Hadoop平台上对改进前和改进后的两种方法进行比较。实验结果表明,改进模式的效率明显得到提高,因此这一方案是可行的。     

基于MapReduce模型单点恢复时阻塞问题的解决方法研究

MapReduce分布式编程模型为大规模数据密集型计算提供了重要的应用基础平台.其任务调度模型为单点控制模型,这种模型使得体系结构简单,任务调度易于控制,但同时也存在中心节点失效的问题.在Hadoop系统中,当中心节点失效后,为了使得整个工作集群中的作业不中断,在不同版本的Hadoop中采取了按需同步、恢复历史记录和抛...     

SparkDE:一种基于RDD云计算模型的并行差分进化算法

云计算MapReduce并行编程模型广泛应用于数据密集型应用领域,基于该模型的开源平台Hadoop在大数据领域获得了成功应用。然而,对于计算密集型任务,特别是迭代运算,频繁启动Map和Reduce过程将导致负载过大,影响计算效率。弹性分布式数据集(RDD)是一种基于内存的集群计算模型,有效地支持迭代运算,能够克服负载过大的问题。因此提出基于RDD模型的并行差分进化算法SparkDE。SparkDE首先将整个种群划分为若干个独立岛,然后将一个岛对应RDD中的一个分区,每个岛在RDD的一个分区中独立进化指定代数后,利用迁移算子在岛之间交换信息。利用标准测试问题对SparkDE、基于MapReduce模型的MRDE和基本DE进行对比实验研究。实验结果表明SparkDE求解精度高,计算速度快,加速效果明显,可以作为云计算平台的下一代优化器。     

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。