kappa-nearest neighbors query in dynamic spatial network databases

随着无线通讯应用的持续增长和定位技术的发展, 如何有效率的应答大量移动对象的查询请求以及基于位置的服务(location-based services LBS)变得越来越重要, kappa-NN查询是其中的重要服务功能.本文提出了一种解决动态网络中静态对象kappa-NN查询算法, 该算法先将网络以目标对象为中心进行网络划分, 通过定位原始对象在网络上的位置来计算位置相关查询.同时还分析了算法的复杂性, 给出了实验比较国家自然科学基金; 教育部留学回国人员科研启动基金One of the most important kinds of queries in Spatial Network Databases to support Location-Based Services is the kappa-Nearest Neighbors (kappa-NN) query. In this paper,we propose a novel approach to efficiently and accurately evaluate k-NN queries in spatial network databases using network space diagram. This approach is based on partitioning a large network to small regions, and then precomputing distances both within and across the regions. Our empirical experiments with several random data sets show that our proposed solution outperforms approaches that are based on on-line distance computation by up to one order of magnitud

The Design and Implementation of An Oil Distribution System of SINOPEC

该文在对信息系统的基本原则及石化销售业务进行分析研究的基础上,建立了分布式信息系统的模型,实现了中石化成品油销售业务信息数据库系统.该系统分析包括销售公司总部、大区公司、省市公司、地市公司、县市公司五层分系统,分别满足相应层次的业务需求.系统中的每一层分系统均以数据库的方式出现,并辅以一组相应的应用软件.五层系统之间建立有机的联系,能密切配合.该文从软件工程学的角度出发,详细描述了中石化成品油销售业务管理信息系统从分析、设计到具体实现的过程及其中解决的关键问题.中石化成品油销售业务管理信息系统采用基于消息中间件的三层分布计算结构,并利用组件技术实现.三层分布计算结构是以消息通信为中心,与以数据库为中心的二层结构相比,一个关键的特征是业务逻辑（或功能）是分布的,并且业务数据是封装在消息中,以消息排队为中介进行信息交换.With the development of the technology of software and hardware, especially the Intranet and Internet, Computers play more and more important role in enterprise management. Based on the analysis of oil distribution modes of SINOPEC, we built an information model, realized the Oil Distribution system of SINOPEC. This system is composed of five subsystems, including headquarters, region company, province company, city company and county company, to satisfy the requirements of different application layer. The subsystem of each layer has a database and a group of applications. All the subsystem can work together well by using EAI technology. This thesis presents the analysis, design, implementation and some key techniques used in Oil Distributuion system of SINOPEC in detail from the view of software engineering method. The distribution system uses a three-tier distributed architecture based on message queuing middleware. The operation data are encapsulated in messages and exchanged by message middleware. The application is implemented by a component software tool DapBuilder. It also has a general congregate module which can be instantiated to many kinds of congregate algorithm with a few key parameters. It can alleviate the pressing of writing a lot of congregate codes in the development of information, system The thesis also presents a study about EAI modes and technology in distributed information system implementation

动态网络空间中的k-NN查询

随着无线通讯应用的持续增长和定位技术的发展,如何有效率的应答大量移动对象的查询请求以及基于位置的服务(location-based services LBS)变得越来越重要,k-NN查询是其中的重要服务功能.本文提出了一种解决动态网络中静态对象k-NN查询算法,该算法先将网络以目标对象为中心进行网络划分,通过定位原始对象在网络上的位置来计算位置相关查询.同时还分析了算法的复杂性,给出了实验比较.One of the most important kinds of queries in Spatial Network Databases to support Location-Based Services is the k-Nearest Neighbors (k-NN) query. In this paper, we propose a novel approach to efficiently and accurately evaluate k-NN queries in spatial network databases using network space diagram. This approach is based on partitioning a large network to small regions, and then precomputing distances both within and across the regions. Our empirical experiments with several random data sets show that our proposed solution outperforms approaches that are based on on-line distance computation by up to one order of magnitude

moving object query k nearest neighbors in spatial network databases

中国计算机学

空间网络数据库中移动对象的最短路线算法

在空间网络数据库中，基于位置的服务(10cation—based services，LBS)变得越来越重要，最短路线查询是最广泛的服务请求之一．假设在网络上有一个原始对象(例如：在道路上行驶的汽车)、有一个目标对象(例如：旅店、加油站、救护车等等)，那么最短路线查询就是要找到原始对象到目标对象的最短路线．最短路线算法的研究主要分为两个方面，实时计算和预计算．在预计算方面，当前的研究对网络空间中的最短路线查询提出了多种解决方式，但是这些方法中都假设目标对象是静止的．文中在原始对象和目标对象都处于移动状态时，给出了一种最短路线查询的 算法．该算法创建了一组索引结构，将计算两个动态点之间最短路线的问题转换为计算静态边之间最短路线的问题．主要关注交通网络．但是该算法不会使用任何领域相关的信息，所以能够被应用到其他的网络环境中．从计算复杂性而言，传统的Dijkstra算法时间复杂性估计是0((i+志)2)，而该算法的相应估计是0(klbi)

移动对象在空间网络数据库上的kNN查询

在空间网络数据库中,基于位置的服务是一项重要功能,而k-NN查询是实现该服务的重要查询.在网络上有一个原始对象(例如在道路上行驶的汽车),有一组目标对象(例如旅店、加油站、救护车等等),k-NN查询返回距离原始对象最近的k个目标对象.在这种对象移动受到网络限制的情况下,网络距离将替代Euclidean距离作为k-NN查询的指标.提出了一种解决移动对象k-NN查询的算法,该算法使用了一组索引结构来解决移动对象的位置问题.实验分析表明这种方法比传统方法的执行效率更高.中国计算机学