Efficient and privacy-preserving skyline computation framework across domains

Skyline computation, which returns a set of interesting points from a potentially huge data space, has attracted considerable interest in big data era. However, the flourish of skyline computation still faces many challenges including information security and privacy-preserving concerns. In this paper, we propose a new efficient and privacy-preserving skyline computation framework across multiple domains, called EPSC. Within EPSC framework, a skyline result from multiple service providers will be securely computed to provide better services for the client. Meanwhile, minimum privacy disclosure will be elicited from one service provider to another during skyline computation. Specifically, to leverage the service provider’s privacy disclosure and achieve almost real-time skyline processing and transmission, we introduce an efficient secure vector comparison protocol (ESVC) to construct EPSC, which is exclusively based on two novel techniques: fast secure permutation protocol (FSPP) and fast secure integer comparison protocol (FSIC). Both protocols allow multiple service providers to calculate skyline result interactively in a privacy-preserving way. Detailed security analysis shows that the proposed EPSC framework can achieve multi-domain skyline computation without leaking sensitive information to each other. In addition, performance evaluations via extensive simulations also demonstrate the EPSC’s efficiency in terms of providing skyline computation and transmission while minimizing the privacy disclosure across different domains.     

基于Skyline的最短路径分析算法设计与实现

最短路径是网络分析的主要问题之一。本文结合Dijkstra算法思想，提出了Skyline三维场景中最短路径分析的设计与实现方案，并通过实例说明方案的可行性，为用户提供了一个更加真实沉浸的可视化环境。     

基于网格和队列触发的多维空间Skyline查询算法

在流数据环境下,多维空间的Skyline计算会随着维度的增高影响滑动窗口上Skyline点集的计算效率.针对以上问题,提出SQTS算法,采用网格索引结构,对元组进行标记,排除部分非Skyline点集;引入SD队列触发Skyline维护,避免过期数据点的频繁排查,提高多维空间下的Skyline计算效率.仿真实验结果表明,SQTS算法在多维流数据环境下,提高了Skyline点集的计算效率,验证了算法有效性.     

多维数据流下的top-k支配查询算法研究

Top-k支配查询算法返回前k个支配得分最高的数据对象,在多维数据查询中有效地限定了结果集的大小,但是无法直接应用于数据流查询中.文中使用网格索引结构在多维数据流下构建的top-k支配算法,采取动态创建网格,反向遍历一次求支配区点数,剪枝无效单元格等策略,提高了查询的效率.实验结果证明了该方法在多维数据流查询中的有效性.     

武汉市的新地标--武汉国际证券大厦

建筑设计是经历了从立意，设计，施工，竣工，使用，变化直至消亡的全过程的一种行为，设计的过程也是蜕变成长的过程。武汉国际证券大厦的设计经历了数年的时间，在桩基已施工的情况下由48层变为66层，其中克服了一个又一个的难题。它的实现意味着武汉市超高层建筑设计逐渐走向成熟。     

Terrasuit 在数字城市中的应用研究

以某地区为例,对Skyline Terrasuit中的TerraExplorer Pro在数字城市用地规划建设中的应用进行了研究,重点讨论了用地规划中的建筑模型设计问题,最后通过对Terrasuit软件进行扩展,实现三维数字城市的模拟建设。     

基于位置的路网Skyline查询处理研究

基于位置的路网Skyline查询可根据用户的需求及用户所处的位置,从大量数据中快速返回给用户期望的数据,但已有的道路网络技术需要计算大量的路网距离及数据点间支配关系的运算,导致查询效率较低。提出一种基于路网数据点的倒排索引查询算法DSR。通过计算少量数据点的路网距离求得最终结果,减小路网距离计算的代价,从而加快数据点间支配关系的判定,提升查询效率。在此基础上,在数据点更新情况下给出算法的动态维护,仅通过维护少量数据,DSR即可以快速地计算出Skyline集合。实验结果表明,与SSI、BSS等算法相比,该算法具有较高的查询效率,且时间性能明显提升。     

欣赏和保护城市轮廓线——旧金山城市设计调查

本文通过作者对旧金山市的实地调查,介绍了其城市轮廓线的层次与建筑布局特点,同时指出,良好的城市规划与设计是保证城市的特色的基础。     

Flexible integration of multimedia sub-queries with qualitative preferences

Complex multimedia queries, aiming to retrieve from large databases those objects that best match the query specification, are usually processed by splitting them into a set of m simpler sub-queries, each dealing with only some of the query features. To determine which are the overall best-matching objects, a rule is then needed to integrate the results of such sub-queries, i.e., how to globally rank the m-dimensional vectors of matching degrees, or partial scores, that objects obtain on the m sub-queries. It is a fact that state-of-the-art approaches all adopt as integration rule a scoring function, such as weighted average, that aggregates the m partial scores into an overall (numerical) similarity score, so that objects can be linearly ordered and only the highest scored ones returned to the user. This choice however forces the system to compromise between the different sub-queries and can easily lead to miss relevant results. In this paper we explore the potentialities of a more general approach, based on the use of qualitative preferences, able to define arbitrary partial (rather than only linear) orders on database objects, so that a larger flexibility is gained in shaping what the user is looking for. For the purpose of efficient evaluation, we propose two integration algorithms able to work with any (monotone) partial order (thus also with scoring functions): MPO, which delivers objects one layer of the partial order at a time, and iMPO, which can incrementally return one object at a time, thus also suitable for processing top k queries. Our analysis demonstrates that using qualitative preferences pays off. In particular, using Skyline and Region-prioritized Skyline preferences for queries on a real image database, we show that the results we get have a precision comparable to that obtainable using scoring functions, yet they are obtained much faster, saving up to about 70% database accesses.     

鄂北地区水资源配置工程三维可视化系统开发

本文主要介绍鄂北地区水资源配置工程三维可视化系统的开发。研究了AutoCAD Civil 3D、ArcGIS Desktop等软件对DEM和DOM的处理,AutoCAD Civil 3D与3DS MAX在建模中的协作,Skyline系列软件的相互协作及对它的二次开发,且系统经过对特定的动态事件进行数学建模,最终获得了较实用的三维可视化系统。