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1.
XML查询语言当中,包含通配符*的查询能够方便有效地满足一些特殊查询要求,但在大数据时代下XML文件容量与结构复杂性不断增加,现有支持通配符查询的算法需消耗巨量内存来解析XML,并且在对嵌套通配符处理时需要大量的单路径匹配操作和局部结果的缓存。针对此现状,结合现有经典算法,提出一种新的、能够高效解决小枝模式当中含有通配符*的查询算法-WTwigList。该算法首先对查询模式进行通配符的层次关系处理,减少不必要的通配符匹配,以数据流形式解析XML文件并执行局部的扩展Dewey编码,经过滤操作后得到有序的叶子节点编码列表,在列表中执行匹配操作得到结果;其次在真实和合成数据集上做大量实验,结果表明WTwigList算法与现有算法相比,能够有效提高查询效率,在空间效率上具有一定优势,且能够快速准确地处理查询模式中P C关系。 相似文献
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手机短信已成为手机应用中双因子验证的常用方法,广泛用于网站登录、移动支付、银行转账等关键应用中。许多恶意软件利用手机系统漏洞来窃听短信和截取用户的验证码,从而对用户的财产安全造成了巨大的威胁。为防御这类恶意软件,许多基于对称密钥、公私钥体制等加密算法的手机短信加密软件已经被开始使用,给用户带来了较大便利。然而此类解决方案并不能保证在智能手机操作系统被攻破时短信明文数据与密钥数据的安全性。本文提出的TrustSMS系统通过利用ARM TrustZone技术,可以同时保证短信数据在传输过程中与在智能手机操作系统内的安全性。本文在三星Exynos 4412开发板上实现了TrustSMS的原型系统,实验数据表明TrustSMS系统对智能手机操作系统产生的影响极小,性能开销则低于1%。 相似文献
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针对目前停车场引导系统存在的诸多弊端,基于Wi-Fi和蓝牙技术的特点以及Android智能手机的功能,提出一种停车场智能引导系统的设计方案。系统采用Android智能手机为客户端,利用Wi Fi和蓝牙技术完成手机客户端与服务器端的数据交互,实现停车场信息统一管理和汽车身份自动验证的功能;利用Dijkstra最短路径算法,实现室内停车场的路线引导功能。系统无需车载其他设备,且停车全过程无需人工操作。 相似文献
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在室内WiFi位置指纹定位系统中,由于室内环境的复杂性及易变性,定位精度很难得到保证。通过实验测试分析人体对WiFi信号的影响以及不同位置设备接入点数目的变化情况,本文提出一种在手持设备的定位系统中增加位置指纹特征以提高定位精度的改进型定位方法。该方法将手持设备的方向角和接入点数目这2个位置特征加入位置指纹中,丰富了离线数据库的位置特征。通过对常规位置指纹库定位和改进的位置指纹库定位的测试对比,得出使用改进的位置指纹库定位可以提高系统的定位精度的结论。 相似文献
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评价对象的抽取能够让用户和商家同时受益,商家通过评价对象了解用户关心的产品特征,改进商品质量;用户通过评价对象做出购买决策。由于网络评论环境特殊,评价对象的抽取比传统的信息处理更复杂。在一些学者研究的基础上,本文提出一种词性规则和依存句法分析相结合的抽取方法。首先,该抽取方法利用词性规则制定名词短语抽取模板,得到候选评价对象,根据评价词对评价对象的修饰作用对评价对象进行第一次筛选;其次,利用8种依存句法关系对评价对象进行第二次筛选;最后,将2种筛选结果进行结合,得到最终的评价对象。实验结果表明,该方法在3类数据集上都取得了一定的效果。 相似文献
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近些年电子商务高速发展,传统零售业受到巨大冲击,转型O2O为大势所趋。零售O2O融合了线上线下交易场景,需要一个高并发高可用的系统支撑。本文针对零售O2O交易系统,分别从系统架构设计和业务逻辑实现2方面,研究并提出一系列高并发、高可用策略。从架构设计的角度,提出并介绍分层解耦、集群负载均衡、混合数据存储、静态化分离的策略;从业务实现的角度,提出并介绍订单库存分区缓存、订单事务降级、库存一致性、请求限号排队的策略。实验证明,这些策略可以有效提升系统的并发性、可用性,具有重要实践参考价值。 相似文献
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分簇路由协议使用分簇算法来提高网络的生命周期,簇头选择是分簇算法中一个关键环节。针对簇头选择这一过程,本文采用一种基于模糊逻辑的2轮簇头选择算法,模糊逻辑包括2个模糊描述:节点的剩余能量和节点到基站的距离。首轮基于模糊逻辑的簇头选择算法不考虑簇头之间的距离,选择结果可能出现簇头之间距离较近,分布不均匀的情况,因此,通过簇头的次轮选择,对于距离太近的簇头节点所在的簇,计算这些簇内的节点之间的链路消耗,将链路消耗最小的节点作为新簇头,使簇头分布均匀。仿真结果表明,在网络的存活节点数量和剩余能量方面,本算法优于LEACH协议和基于模糊逻辑的一轮簇头选择算法。 相似文献
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In order to overcome the
disadvantages of relay-contactor control, i. e. more failures, low reliability and huge maintenance,
the applications of programmable controller (PLC) for coal-preparation in coking process and coke sieve
system are introduced. The selection of the PLCs, design criteria and the anti-interference measures in
installation and test are emphasized. 相似文献
11.
European Community policy and the market 总被引:1,自引:0,他引:1
C. Lloyd 《Journal of Computer Assisted Learning》1993,9(2):86-91
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. 相似文献
12.
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。 相似文献
13.
张涛 《计算机测量与控制》2015,23(1):86-89
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. 相似文献
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15.
潘丽 《自动化与仪器仪表》2014,(7):80-82
自然界的绝大部分信号都是以模拟的形式存在,因此模拟信号的采集转换存储在数字时代十分关键。文章讨论了在雷达信号处理领域基于AD9626的AD采集存储卡的设计原理、硬件结构和程序设计与芯片配置等问题,为今后相关领域的研究提供了可参考的方案。 相似文献
16.
Jacob Palme 《Software》1979,9(9):741-747
The COM teleconferencing system was designed to be easy to use for both beginners and people with much computer experience. A number of design choices in organizing the human-computer interface were considered very carefully. These design problems are not unique for teleconferencing applications, but will appear in many other developments of human-computer interfaces for non-computer specialists. This report discusses naming conventions, menu format, user commands, help facility and the treatment of ‘type ahead’ from the users. 相似文献
17.
David Poole 《Computational Intelligence》1989,5(2):97-110
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. 相似文献
18.
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. 相似文献
19.
《控制理论与应用(英文版)》2014,(3)
正The control of civil,energy,and power systems presents significant new challenges for modeling and control theory.The purpose of this special issue is to provide a forum for researchers and practical engineers to discuss the recent advances in modeling and control technology development for civil,energy,and power systems.Prospective authors are invited to submit their original contributions with the focus on theory or applications of modeling,control 相似文献
20.
《浙江大学学报:C卷英文版》2014,(12)
正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and overseas to the world’s scientific circles,especially to stimulate and promote academic exchange between Chinese and foreign scientists everywhere. 相似文献