一种并行数据库的动态多维数据分布方法

并行数据库系统的性能与数据库在多处理机之间的分布密切相关.目前已经出现一些并行数据库的数据分布方法.但是,这些方法都不能有效地支持动态数据库.文章提出了一种并行数据库的动态多维数据分布方法.该方法不仅能够有效地支持动态数据库的分布,还具有多维数据分布的诸多优点.此方法由初始数据分布机构和启发式动态数据分布调整机构组成.初始分布机构完成给定数据库文件的初始分布.动态数据分布调整机构实现动态数据库数据分布的动态调整.理论分析和实验结果表明,这种方法十分有效,并且能够有力地支持动态数据库上的各种并行数据操作算法.     

数据库网格:基于网格的多数据库系统

近年来,数据网格技术的快速发展为广域分布环境下的海量数据共享提供了强有力的支持。数据库网格是指主要由各种数据库管理系统构成的数据网格环境,其技术难点是在网格环境下研究解决分布式查询、事务、多数据源视图等传统的数据库领域的问题。该文通过讨论数据网格、数据库网格和多数据库的概念和特点,并比较上述问题在多数据库和数据库网格环境下的异同,对数据库网格的特点进行了总结,对数据库网格技术的研究和发展方向进行了探讨和展望。     

多功能数据库结构分布和功能发挥研究

多功能数据库的结构分布和功能有着显著的特征,它在结构分布上主要体现在管理信息系统性能的提高,功能的发挥则是体现在MIS中的信息管理过程。本文对多功能数据库的结构分布和功能发挥进行研究和探讨,以此来提升多功能数据库在操作上的认识度。     

多功能数据库结构分布和功能发挥研究

多功能数据库在结构分布和功能发挥上有着显著的特征,它在结构分布上主要体现在管理信息系统性能的提高,功能的发挥则是体现在MIS中的信息管理过程中发挥的功能。多功能数据库系统则是采取有效的措施来完成数据库子系统的操控,所以本文就对多功能数据库的结构分布和功能发挥进行研究和探讨。     

防汛综合数据库集成元数据库设计

根据防汛综合数据库的异构、分布特征,提出集成防汛综合数据库的元数据方法。在介绍元数据的基本内容、元数据标准的基础上,探讨了防汛综合数据库集成的元数据编码原则与总体结构,分析设计了支持防汛综合数据库多数据库集成的元数据库,并在某水库调度决策自动化系统中实现了基于元数据库的分布式多数据库系统的集成。     

ORACLE数据库中异地数据的存取技术

介绍多结点分布存储的ORACLE数据库中,对异地数据库数据进行存取的技术.     

基于CSCW下Web多数据库协同管理的研究

Web已经为用户合作提供了良好的环境。基于协作的企业多数据库的特点，分析了CSCW环境下数据库多态性、自制性和分布性，提出了CSCW环境下基于Web的多数据库协同管理的模型以及用户程序对多数据库访问的连接语言模型和实现策略。     

基于分布结构自适应筛选的数据库存储优化设计

通过对数据库的存储结构优化设计,提高数据库的吞吐量。传统方法采用存储节点校验数据适应度分区的数据库存储模型,数据库中存在重复冗余数据,不能自适应滤除,导致数据存储开销较大。提出了一种基于分布结构自适应筛选的数据库存储优化模型,首先进行数据库的存储机制和分布式数据结构分析,采用相空间重构方法进行存储空间的结构分布重组,采用分布结构自适应筛选方法对提取的数据信息流进行重复冗余数据滤波处理,改善数据在数据库存储空间中的结构分布,实现数据库存储优化。仿真结果表明,采用改进的方法进行数据库构建,能提高数据库存储吞吐量,降低数据存储开销,提高数据库的访问和调度性能,展示较好的应用价值。     

网格环境中异构数据库集成的模型

在分析网格环境中异构数据库集成问题的基础上,提出分布环境下异构数据库集成的一种模型.该模型采用基于网格计算中间件GT4的网格数据服务,结合XML技术作为异构数据库集成的载体,利用HTTP传输协议,初步实现了异构数据库的集成.     

福建省人体寄生虫数据库管理及其应用管理

为了更好地发挥我省人体寄生虫分布调查数据库的服务效能和管理工作的现代化,为政府主管部门做出科学决策及制定防治、科研、教学工作提供服务。我们将全省26个县市6万多人的调查结果建立各种数据库,并对数据库的管理、应用分析进行了研究,以促进部门工作的科学化和现代化。     

一种P2P数据库系统的资源定位机制

以结构化的DHT P2P网络作为分布式平台,探讨一种P2P数据库的数据索引和定位机制。我们主要使用数据复制和分层索引机制来保证高效的实现资源定位,并且避免了Hash对数据语义的破坏,使系统有效的保持数据语义间的联系。     

Efficient location area planning for cellular networks with hierarchical location databases

Location area planning (LAP) is an important issue in the design of high-performance PCS networks. It could have a serious impact on the total mobility management cost of mobile terminals. Most of the previous works either explored the LAP problem as a 0–1 linear programming problem or used adopted techniques, such as simulated annealing, taboo search, and genetic algorithms [IEEE Trans. Vehicular Technol. 49 (2000) 1678; Proceedings of 1999 Vehicular Technology Conference, vol. 4, 1999, pp. 2119–2123; IEEE Vehicular Technol. Conf. 3 (1996) 1835; Proceedings of IEEE INFOCOM'01, Anchorage, Alaska, April 2001; IEEE Trans. Vehicular Technol. 47 (1998) 987], to derive a solution to minimize the location update cost. In this paper, we model and resolve the LAP problem as a set-covering problem. The main advantage of this approach is that it can adapt to the changing mobility patterns of the mobile terminals. We propose the set-covering-based location area planning (SCBLP) algorithm to minimize the total number of location updates, in which the cost-benefit functions are defined based on the coupling and cohesive functions among neighboring cells. We then apply SCBLP to the location database system with a hierarchical structure to further improve the overall system performance in searching and updating the location databases. Extensive simulation experiments have been conducted, and the experimental results show that our proposed algorithms can significantly reduce the location management costs, compared to the greedy algorithm and the random algorithm.     

移动客户机位置管理研究

随着移动数据库和移动通信技术的发展,客户要求能在任何地点随时访问他所需要的信息。该文就是基于客户机移动的不确定性,从影响位置管理的两个方面:位置更新和位置查询出发,在分析前人的研究成果基础上,提出了一种基于虚拟服务器的位置管理方案,分析了其基本结构和工作流程。最后作了简短评价,并提出了以后的研究方向。     

面向Android应用的细粒度位置隐私保护系统

位置隐私保护是移动定位服务中的关键安全问题,粗粒度的访问控制机制通过绝对的授权策略抑制了位置信息的暴露,但是忽略了用户的服务质量。提出一种针对本地位置信息的时空模糊算法,实现了细粒度的位置隐私保护系统,在保障用户服务质量的前提下实现位置信息的模糊,从而达到隐私保护的目的。首先设计了一种针对应用程序位置服务请求的位置信息拦截技术,截获精确位置信息,并使用位置模糊算法进行模糊处理;将模糊后的安全位置信息返回给Apps,从而实现位置隐私保护。实验结果证明了该方法的有效性。     

Efficient primal-dual heuristic for a dynamic location problem

In this paper the dynamic location problem with opening, closure and reopening of facilities is formulated and an efficient primal-dual heuristic that computes both upper and lower limits to its optimal solution is described. The problem here studied considers the possibility of reconfiguring any location more than once over the planning horizon. This problem is NP-hard (the simple plant location problem is a special case of the problem studied). A primal-dual heuristic based on the work of Erlenkotter [A dual-based procedure for uncapacitated facility location. Operations Research 1978;26:992–1009] and Van Roy and Erlenkotter [A dual-based procedure for dynamic facility location. Management Science 1982;28:1091–105] was developed and tested over a set of randomly generated test problems. The results obtained are quite good, both in terms of the quality of lower and upper bounds calculated as in terms of the computational time spent by the heuristic. A branch-and-bound procedure that enables to optimize the problem is also described and tested over the same set of randomly generated problems.     

A simple and effective evolutionary algorithm for the capacitated location–routing problem

This paper proposes a hybrid genetic algorithm (GA) to solve the capacitated location–routing problem. The proposed algorithm follows the standard GA framework using local search procedures in the mutation phase. Computational evaluation was carried out on three sets of benchmark instances from the literature. Results show that, although relatively simple, the proposed algorithm is effective, providing competitive results for benchmark instances within reasonable computing time.     

Simultaneous location of a service facility and a rapid transit line

This paper presents a location problem on the plane where a single service facility and a rapid transit line have to be simultaneously located. The rapid transit line represents an alternative transportation line which can be used by clients whenever it provides a cost-saving or time-saving service, and it is given by a segment with fixed and known length. This type of problems has not previously been considered in the Location Theory literature, as we are only aware of the existence of models that consider the location of service facilities in the presence of an already located alternative transportation system or models dealing with the location of rapid transit lines to minimize the travelling time among a set of points. To solve this problem we will develop an algorithm based on some characterizations of the objective function behavior.     

基于优化Daugman算法的出租车标志定位

针对传统的Hough变换算法定位圆状目标时易受到干扰,效果不佳,导致定位出现较大偏差的问题,提出了一种基于优化的Daugman算法的定位方法来实现对于出租车标志定位.该算法引进一种优化的Daugnum算子并使用阈值经验以提高出租车标志判断与定位的精确度.实验表明,使用该算法判断与定位出租车标志准确且抗干扰性强,从而能有效地定位出租车标志.     

Simultaneous scheduling and location (ScheLoc): the planar ScheLoc makespan problem

While in classical scheduling theory the locations of machines are assumed to be fixed we will show how to tackle location and scheduling problems simultaneously. Obviously, this integrated approach enhances the modeling power of scheduling for various real-life problems. In this paper, we introduce in an exemplary way theory and three polynomial solution algorithms for the planar ScheLoc makespan problem, which includes a specific type of a scheduling and a rather general, planar location problem, respectively. Finally, a report on numerical tests as well as a generalization of this specific ScheLoc problem is presented.     

Skewed general variable neighborhood search for the location routing scheduling problem

The integrated location routing scheduling problem is a variant of the well-known location routing problem. The location routing problem consists in selecting a set of depots to open and in building a set of routes from these depots, to serve a set of customers at minimum cost. In this variant, a vehicle can perform more than a single route in the planning period. As a consequence, the routes have to be scheduled within the workdays of each vehicle. The problem arises typically when routes are constrained to have a short duration. It happens for example within the boundaries of small geographic areas or in the transportation of perishable goods. In this paper, we propose a skewed general variable neighborhood search based heuristic to solve it. The algorithm is tested extensively and we show that it is efficient and provides the proven optimal solution in a significant number of cases. Moreover, it clearly outperforms a multi-start VND based heuristic that uses the same neighborhood structures.