基于LSH索引的快速图像检索

高维空间中点数据的索引及检索是基于内容图像检索领域的关键问题,文中将LSH(localitysensitivehashing)索引算法应用于基于内容图像检索系统中,与传统的索引方法相比,该算法具有复杂度比较低、支持非常高的维数、极低的I/O代价等特点。实验结果证明,将该索引算法应用于基于内容图像检索系统中,其性能优于传统的索引方法.     

面向桌面环境的索引实时更新方法

在桌面计算环境中,文件和目录频繁发生新建、删除、修改、重命名、移动、复制等变化,这对桌面索引更新的实时性和性能提出更高要求,而传统的桌面索引更新方法完全或部分依赖周期性全盘扫描,往往需要大规模索引重建,导致索引生成延迟大、系统资源占用高.针对这些弊端,本文提出了一种基于文件系统事件监听的桌面索引实时更新方法,并实现了相应的桌面索引实时更新系统.实验表明：本文提出的索引更新方法延迟低、系统资源占用低.     

OLAP数据的索引

用于联机分析处理数据的索引方法,并对传统的多维索引方法提出一些扩展方式,以使它们更适于索引OLAP数据。     

基于SOM和统计检验的语音特征索引技术

本文在深入介绍线性预测编码、倒谱及Gabor滤波法等三种语音特征抽取方法的基础上,提出基于SOM和统计检验的索引、分段索引以及二重索引的方法用于多媒体声音的自动检索。该方法弥补了传统索引方法的不足,适应语音特征,有效地将语音特征动态索引。仿真结果显示,该方法的查询效率要远远优于顺序查找,基本达到了特征索引的要求。     

基于聚类索引树的高维近似检索算法

提出了一个基于聚类索引树的高维近似检索方法。详细描述了其建树算法和检索算法。由于传统索引对高维空间的k-近邻检索效率的提高非常有限，我们把近似检索和聚类索引树结合起来。从而用很小的精度损失换取很高的检索效率。实验表明，与精确检索相比，本方法的误差非常小，而检索速度大大优于其他方法，因此具有广泛的应用前景。     

面向轨迹流数据的索引构建与存储方法研究

移动社交网络等基于定位服务应用的快速发展导致时空数据流规模呈爆炸式增长,要求底层数据存储系统支持高吞吐量轨迹数据的插入以及空间和时间约束下的低延迟查询,而现有HBase等数据存储方案因索引更新开销过高无法满足该需求。针对时空数据流的应用特性,提出一种数据流内存索引及存储方法。根据键值和时间范围对历史与增量数据元组进行物理分区,将其以模板B+树的形式写入内存并构建索引以增强快速写入和查询能力,同时对数据进行压缩存储提升索引效率。在此基础上,采用多级索引根据数据分区将复杂查询分解为可独立处理的子查询。实验结果表明,与传统HBase、WaterWheel等方法相比,该方法在不同数据插入和查询条件下的数据存储性能与查询效率更优。     

面向大规模图数据的分布式可达性索引与查询策略

针对构建大规模图数据可达性索引时的构建时间长、存储代价高和响应时间长等问题,提出一种分布式可达性索引与查询策略(DRIQ)。在不破坏原图中节点可达性的前提下,将大规模图划分成若干小规模子图,并对每个子图分布式并行地创建可达性索引,从而提高可达性索引创建效率。给出保持图划分后各子图内节点间以及子图间节点可达性的方法,从而保证基于DRIQ进行可达性查询的正确性。实验结果表明,与传统可达性查询方法相比,该策略具有高效性和可扩展性。     

HBase中基于时空特征的监测视频大数据关联查询研究

针对传统的时空索引构建、维护困难且实时查询效率低等问题,首先提出基于HBase的时空索引构造方法。该方法采用HBase作为监测视频大数据时空特征索引结构,通过Z填充曲线对空间特征进行降维存储,并利用时间、空间和属性特征之间的关联及依赖规则来安排rowkey索引键,可有效解决传统的时空索引构建、维护困难的缺陷。此外,针对传统的时空索引实时查询效率低的问题,进一步提出了基于Z曲线的时空关联查询算法,该算法对查询空间计算Z值范围和建立空间划分子集,利用划分后的时空特征进行列索引查询得到候选数据集并反查HBase索引表完成关联查询。实验结果表明,与传统的R树索引算法相比,提出的基于HBase的时空索引构造方法索引插入效率更高,提出的基于Z曲线的时空关联查询算法能够快速高效地处理时空关联查询。     

空间数据库索引技术的研究

空间数据库的索引是提高空间数据库存储效率、空间检索性能的关键技术。传统的索引技术不能有效地索引空间数据。在综述现有空间数据库索引技术的基础上，提出了一种面向大型空间数据库的QR-树索引方法。     

移动GIS的空间数据索引研究与实现

与传统的数据库中的数据相比,空间数据有数据量大,维数高,空间实体间关系更为复杂等特点。充分研究空间数据特性的基础,对空间数据存储方式进行了较为详细的分析,讨论了各种针对空间数据的空间索引技术,并针对移动GIS的应用实现了一种四叉树索引方法。     

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.     

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.     

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.     

The Distributed Time-Triggered Simulation Scheme: Core Principles and Supporting Execution Engine

Distributed real-time simulation is a young technology field but its practice is under increasing demands. In recent years the author and his collaborators have been establishing a new approach called the distributed time-triggered simulation (DTS) scheme which is conceptually simple and easy to use but widely applicable. The concept was initiated in the course of developing a new-generation object-oriented real-time programming scheme called the time-triggered message-triggered object (TMO) programming scheme. Some fundamental issues inherent in distributed real-time simulation that were learned during recent experimental studies are discussed along with some approaches for resolving the issues. An execution engine developed to support both the TMOs engaged in control computation and the TMOs engaged in DTS is also discussed along with its possible extensions that will enable significantly larger-scale DTSs.     

Software-Konfigurationsmanagement in großen Softwareprojekten

Zusammenfassung Mit zunehmender Größe der Softwaresysteme verschärfen sich die für die Software-Herstellung typischen Probleme: Beherrschen großer Objektmengen, Erhalten der Systemkonsistenz, Kontrolle der ständigen Änderungseinflüsse und Gewährleisten einer langen Lebensdauer. Die Disziplin Konfigurationsmanagement bildet den methodischen Ansatz, diese Probleme besser zu beherrschen. Software-Konfigurationsmanagement faßt die Herstellung von Softwaresystemen als eine Abfolge von kontrollierten Änderungen an gesicherten Zwischen- und Endergebnissen auf. Dargestellt werden die Objekte und Funktionen des Software-Konfigurationsmanagements sowie die hierfür in großen Software-Projekten benötigten Methoden, Instanzen und Hilfsmittel.     

Information for Authors

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     

Editorial:Brain-machine interface(BMI) and cyborg intelligence

正Brain-machine interfaces(BMIs)aim at building a direct communication pathway between the brain and an external device,and represent an area of research where significant progress has been made during the past decade.Based on BMIs,mind information can be read out by neural signals to control     

Information for Authors

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     

SCIENCE CHINA Information Sciences SUBJECT INDEX TO VOLUME 57(2014)

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