一种基于Redis的分布式爬虫系统设计与实现

随着互联网技术的飞速发展,互联网信息和资源呈指数级爆炸式增长。如何快速有效的从海量的网页信息中获取有价值的信息,用于搜索引擎和科学研究,是一个关键且重要的基础工程。分布式网络爬虫较集中式网络爬虫具有明显的速度与规模优势,能够很好的适应数据的大规模增长,提供高效、快速、稳定的Web数据爬取。本文采用Redis设计实现了一个主从式分布式网络爬虫系统,用于快速、稳定、可拓展地爬取海量的Web资源。系统实现了分布式爬虫的核心框架,可以完成绝大多数Web内容的爬取,并且节点易于拓展,爬取内容可以定制,主从结构使得系统稳定且便于维护。     

基于WebDriver的定向网络爬虫设计与实现

随着Web 2.0的兴起,网络上的海量信息迎来了爆发性地增长。从网络上的公开数据中提取有效信息成为了数据挖掘领域的新热点。数据获取是数据分析的第一步。Web 2.0时代的网站在内容和形态方面发生了深刻的变化,对传统的以静态页面分析为基础的网络爬虫提出了新的挑战。本文利用Web Driver实现了一个定向网络爬虫,该爬虫能够自动采集指定网页数据,支持Ajax等动态技术,能够对简单验证码进行识别,并绕过爬虫检测。利用该爬虫对全国企业信用信息系统进行爬取,取得了良好效果。     

基于最优查询的多领域deep Web爬虫*

Deep Web信息通过在网页搜索接口提交查询词获得。通用搜索引擎使用超链接爬取网页,无法索引deep Web数据。为解决此问题,介绍一种基于最优查询的deep Web爬虫,通过从聚类网页中生成最优查询,自动提交查询,最后索引查询结果。实验表明系统能自动、高效地完成多领域deep Web数据爬取。     

基于WEB挖掘的网络爬虫设计与实现

从介绍Web挖掘与数据挖掘的差异入手, 分析Web挖掘中Web爬虫的必要性和现代Web挖掘技术的发展方向, 在深入了解Web爬虫的原理及其功能的基础上, 提出一个现代网站通用的挖掘模型, 并利用该模型设计一种网络爬虫. 经实例证明, 该爬虫能高效爬取更多的各种页面数据.     

基于python的互联网数据爬取与解析的研究与实践

随着信息的多元化和大数据时代的到来,人们在生活中对网络的应用越来越广泛,使得网络拥有了海量的数据。如何在庞大的网络数据中高效快速地获取对用户有用的信息是一项尤为重要的技术。笔者着重研究了网络数据爬取技术中基于Python语言第三方库的网络爬虫技术,并尝试利用该技术对部分网站数据进行爬取、解析和重新建构。     

主题Deep Web爬虫框架研究

为满足用户精确化和个性化获取信息的需要,通过分析Deep Web信息的特点,提出了一个可搜索不同主题Deep Web 信息的爬虫框架.针对爬虫框架中Deep Web数据库发现和Deep Web爬虫爬行策略两个难题,分别提出了使用通用搜索引擎以加快发现不同主题的Deep Web数据库和采用常用字最大限度下载Deep Web信息的技术.实验结果表明了该框架采用的技术是可行的.     

大数据背景下网络爬虫框架的应用研究

在当前大数据背景下,企业面临数字化的转型升级,数据成为无形的资产.在对网络爬虫的产生背景和相关原理、流程进行研究的基础上,应用Python的网络爬虫框架Scrapy对网站信息进行爬取,提高了信息获取的效率和效果.实践表明,Scrapy框架简单易用,具有非常高的可行性、有效性,使用户有良好的体验,为相关人员开展数据爬取工作提供了借鉴.     

深层网络爬虫研究综述

随着Internet的迅速发展,网络资源越来越丰富,人们如何从网络上抽取信息也变得至关重要,尤其是占网络资源80%的Deep Web信息检索更是人们应该倍加关注的难点问题。为了更好的研究Deep Web爬虫技术,本文对有关Deep Web爬虫的内容进行了全面、详细地介绍。首先对Deep Web爬虫的定义及研究目标进行了阐述,接着介绍了近年来国内外关于Deep Web爬虫的研究进展,并对其加以分析。在此基础上展望了Deep Web爬虫的研究趋势,为下一步的研究奠定了基础。     

基于网页标题的主题相关度算法的研究

首先,给出了主题爬虫的概念;然后介绍了主题相关度计算的两种模型;布尔模型和空间向量模型;通过对两种模型进行分析,提出了一种基于网页标题的空间向量模型主题相关度计算方法Relative.经过试验分析,该算法具有很好的实用性,基于该算法的主题爬虫系统能够在Web上爬取高度主题相关的网页,极大的提高了网络爬虫的效率.     

一种Deep Web爬虫的设计与实现

随着World Wide Web的快速发展,Deep Web中蕴含了越来越多的可供访问的信息.这些信息可以通过网页上的表单来获取,它们是由Deep Web后台数据库动态产生的.传统的Web爬虫仅能通过跟踪超链接检索普通的Surface Web页面,由于没有直接指向Deep Web页面的静态链接,所以当前大多数搜索引擎不能发现和索引这些页面.然而,与Surface Web相比,Deep Web中所包含的信息的质量更高,对我们更有价值.本文提出了一种利用HtmlUnit框架设计Deep Web爬虫的方法.它能够集成多个领域站点,通过分析查询表单从后台数据库中检索相关信息.实验结果表明此方法是有效的.     

Call for Papers The 6^th International Conference on Grid and Cooperative Computing

Recent years have seen rapid advances in various grid-related technologies, middleware, and applications. The GCC conference has become one of the largest scientific events worldwide in grid and cooperative computing. The 6th international conference on grid and cooperative computing (GCC2007) Sponsored by China Computer Federation (CCF),Institute of Computing Technology, Chinese Academy of Sciences (ICT) and Xinjiang University ,and in Cooperation with IEEE Computer Soceity ,is to be held from August 16 to 18, 2007 in Urumchi, Xinjiang, China.     

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.     

法律信息库系统

本文分析了法律数据库的结构和特点，介绍了采用面向对象设计方法和超文本数据库技术开发和实现法律信息库系统将作为重要网络资源之一为不同用户进行法律咨询服务。     

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.     

International Journal of Automation and Computing Table of Contents

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Information for authors

正SCIENCE CHINA Information Sciences(Sci China Inf Sci),cosponsored by the Chinese Academy of Sciences and the National Natural Science Foundation of China,and published by Science China Press,is committed to publishing highquality,original results of both basic and applied research in all areas of information sciences,including computer science and technology;systems science,control science and engineering(published in Issues with odd numbers);information and communication engineering;electronic science and technology(published in Issues with even numbers).Sci China Inf Sci is published monthly in both print and electronic forms.It is indexed by Academic OneFile,Astrophysics Data System(ADS),CSA,Cabells,Current Contents/Engineering,Computing and Technology,DBLP,Digital Mathematics Registry,Earthquake Engineering Abstracts,Engineering Index,Engineered Materials Abstracts,Gale,Google,INSPEC,Journal Citation Reports/Science Edition,Mathematical Reviews,OCLC,ProQuest,SCOPUS,Science Citation Index Expanded,Summon by Serial Solutions,VINITI,Zentralblatt MATH.     

Erratum to: Fast global kernel fuzzy c-means clustering algorithm for consonant/vowel segmentation of speech signal

正Erratum to:J Zhejiang Univ-Sci C(ComputElectron)2014 15(7):551-563doi:10.1631/jzus.C1300320The original version of this article unfortunately contained mistakes.Algorithm 6 should be as follows:Algorithm 6 FGKFCM-F clustering Input:(1)X={x_1,x_2,…,x_N},,x_iR~d,i=1,2,…,N,the dataset;(2)C,1C≤N,the number of clusters;(3)ε0,the stopping criterion;     

Journal of Zhejiang University-SCIENCE C (Computers & Electronics) Total contents

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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.