时态拟序数据结构研究及应用

时态数据索引是实现时态数据有效管理的关键技术之一.讨论了一种时态数据结构及其在时态数据索引上的应用.常规的时态数据管理技术多基于代数框架.提出了一种基于拟序关系的时态数据结构,该结构能够像常规关系数据那样实现“一次一集合”的数据操作,并可通过多线程提高查询效率.在此基础上,研究了一种时态数据索引TQOindex.首先,提出时间期间集合上拟序关系和线序划分概念,讨论了线序划分的最优(最小)性质和构建算法,并在最小线序划分框架内研究时态拟序结构基于增量式更新的插入和删除算法.其次,研究了时态拟序结构应用——引入基于拟序扩展集的时态数据索引 TQOindex.该索引适用于磁盘(外存)数据管理,可在常规数据库平台上有效使用.其增量式更新机制可应用于“大数据”的动态索引技术.另外,对TQOindex进行了基本仿真,实验结果表明了该工作的可行性和有效性.提出的时态拟序数据结构着眼于新型数据,如语义数据、XML数据和移动对象数据中时态处理与整合机制,相应的工作具有较为广泛的应用扩展性.     

一种基于线序划分的时态数据索引技术

讨论一种基于线序划分的时态数据索引技术。首先,讨论了时间期间集合上线序划分概念及其构建算法;其次,提出了基于常规磁盘方式进行数据管理的时态数据库索引技术TQOindex;另外,对TQOindex进行的基本实验仿真表明了其可行性和有效性。TQOindex的基本特征是基于"序关系"数学框架,能够实现"一次一集合"的数据操作。     

基于时态编码和线序划分的时态XML 索引

研究了一种基于时态编码和线序划分的时态XML索引机制.首先,提出一种基于扩展先序编码的时态编码方案,通过该编码可确定结点间的结构关系;其次,在深入分析时间区间关系的基础上引入线序划分的概念,并讨论了获取线序划分的算法;然后,建立了整合路径结构信息和时态约束信息的时态结构摘要,并在此基础上建立了时态XML索引结构—TempSumIndex,同时研究了基于TempSumlndex的时态XML查询和增量式更新算法;最后,对TempSumlndex和现有时态XML索引技术的基本性能进行了详细的实验评估.实验结果表明,TempSumlndex具有更为优越的性能.     

一种基于时态中间件的高效双时态索引模型

当前的时态数据库中间件不支持包含事务时间和有效时间的双时态数据索引,通过使用适当的数据变换和查询变换,可将双时态数据转化为R树可索引的数据.基于4R技术,提出了作为时态中间件TimeDB组件的双时态索引模型B4Rindex.实验证明,利用该模型对双时态数据进行索引是高效的.     

语义协同时态XML索引研究与实现

该文研究一种以语义为基本要素并实现"语义"、"时间"和"结构"处理协同联动的时态XML索引技术SCTindex.首先,以时态结点为数据处理逻辑单元,在时态结点集合上建立基于线序划分的时态数据结构,这种结构具有相应的"拟序关系"数学基础,便于推广,能够实现"一次一集合"的查询方式,具有较高的时间查询效率;其次,以结点语义标签为数据处理技术单元,建立语义标签归并集合,在语义层面配置基于线序划分的时间索引机制,体现了XML本体要素——"语义"与时态数据基本内涵——"时间"约束间的整合联动;另外,引入带有足够结构信息和能够实现"更新友好"的结点编码方案GDFC,建立了相应时态数据的结构连接算法,实现了"结构"与"语义"协同处理.论文主要贡献是基于计算机协同处理理念,较精细地分析时态XML数据的"语义"、"结构"和"时间"等查询要素的本体特征和内在关联,提出了具有较高查询效率的线序划分结构,同时将其配置在语义层面,实现了不同于常规的以"结构摘要"为主轴部署查询的索引模式.论文进行基本实验仿真,通过与现有相关工作进行比较评估,表明SCTindex的可行性、有效性和优越性.     

偏序时态XML索引TempPartialIndex

时态数据管理是常规数据管理的深化和扩展,具有理论研究的意义与实践应用的价值.时态数据索引是时态数据管理的重要技术支撑,是其中的一个研究热点.首先,提出了一种时态数据结构,通过数据节点间的偏序关系,可将常规的二维时间区间的处理转化为基于偏序的时态等价类上的一维的处理,该数据结构可以快速有效地处理时态操作;其次,在该新型时态数据结构基础上研究了时态XML索引TempPartialIndex,其基本特征是将时态数据结构整合到非时态的XML索引中,即,将其整合到语义层之中,通过时态过滤和语义过滤掉大量节点之后,再进行结构连接;另外,着重讨论了基于TempPartialIndex“一次一集合”及其时态变量查询和增量式的动态更新机制.同时,仿真结果表明：TempPartialIndex能够有效地支持时态XML的各类查询及更新操作,技术上具有可行性和有效性.     

时态拟序数据索引TQD-tree

讨论一种新的时态数据库索引技术TQD-tree.不同于常规的“代数”方式,TQD-tree基于“序关系”数学框架,但与“代数”方式一样能够实现“一次一集合”的数据操作.提出给定时间期间集合上线序划分概念并建立构建算法,在线序划分框架内,提出时态数据索TQD-tree,并研究了相应查询和更新算法.设计了仿真实验,对TQD-tree的性能进行了基本评估.     

一种可行的时态数据库索引技术*

提出了一种基于历史关系数据库的时态索引技术,结合时空要求和时态数据库的特征对该索引技术进行了改进和优化,并将其与数据库传统技术一起应用以适应各种时态数据操作的需要。     

基于MapRed uce的增量式数据集的相似性连接

相似性连接,即利用相似函数度量数据之间的相似程度,满足条件后进行连接操作。MapReduce框架下已存在很多相似性连接算法,但仍然存在一些不足,如大量的索引加大时间、空间的开销;现有算法不能有效地完成增量式数据集的相似性连接等。针对海量增量式数据集进行了研究,采用抽样技术得到有效中枢,形成更为合理的分区,建立分区索引和分配原则,完成新增数据的相似性连接操作。实验证明,该算法能够有效地解决海量增量式数据集的相似性连接问题,验证了分区索引的建立,可以提高新增数据的相似性连接操作的效率。     

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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