无线传感器网络中基于哈希函数的上下文隐私保护

在事件驱动的传感器网络中,为了阻止攻击者利用网络上下文的相关性推断出关键资产的位置隐私信息,该文基于哈希函数的节点匿名方法提出了1种迷宫环机制(MCA)。与洋葱路由(Tor)、心跳包路由和幻影路由相比,MCA是1种可以实现节点的身份匿名和保护位置隐私的安全路由协议。与幻影路由相比,MCA可降低延时和能耗达25%。     

基于幻影路由的增强型源位置隐私保护协议

针对目标监测型无线传感网中源节点位置隐私保护问题,提出一种基于幻影路由的增强型源位置隐私保护协议(enhanced protocol of source-location privacy preservation based on phantom routing,ESLBPR).该协议通过一种扇形区域划分方案以及扇形域中改进型幻影路由机制,较好地保护了源节点的位置隐私.该协议具有以下优势:面对较强攻击者,不会发生方向信息泄露;相邻时序产生的幻影节点间的距离及路由至相同幻影节点的可能性得到控制;产生数量众多,分布多样化的幻影节点;幻影节点与源节点的距离进一步增大.理论与仿真实验表明,与已有的源位置隐私保护协议相比,ESLBPR协议在能耗不显著增加的情况下,使得源位置隐私保护的安全性能大幅度提升.     

基于角度和概率的WSN源位置隐私保护路由研究

在无线传感器网络源位置隐私保护问题中,针对具有局部流量分析行为的逐跳反向攻击者,提出了基于随机角度和概率转发的源位置隐私保护路由协议RAPFPR。该协议主要分为两个阶段:真实源节点根据随机角度和距离的有向路由阶段,幻影节点到基站的概率转发路由阶段。协议产生的幻影节点能够很好地均匀分布在真实源节点周围,且采取概率转发路由大大减少了重合路径的产生,增加了逐跳反向攻击的难度。仿真结果表明,与现有的隐私保护方案相比,该路由协议能够在不显著增加通信开销的前提下,有效延长网络的平均安全时间,具有很好的隐私保护性能。     

无线传感器网络中源位置隐私保护方法

随着物联网的迅猛发展,位置隐私被认为是传感器网络中一个重要的安全问题。传统的加密方法不能有效地防止攻击者通过逆向追踪的方式来找到监测物体的位置。针对这些问题并考虑到攻击者具有较强的可视能力,本文提出了一种基于区域和兄弟节点选择的位置隐私保护策略(PRABNS,phantom routing based on area and brother neighbor selecting)。该策略能够使幻影节点均匀分布在源节点周围,并通过对部分区域的选择来使相邻数据包间隔一定的角度,选择兄弟节点来增加源节点到基站路径的多样性。仿真结果表明,该策略能提供更好地隐私保护性,在不增加太多能耗的前提下延长了安全时间。     

WSN中基于伪正态分布的幻影路由隐私保护方案

为提高无线传感器网络中的源节点隐私保护安全性能,提出一种基于伪正态分布的幻影路由隐私保护（source-location privacy protection strategy through pseudo normal distribution-based phantom routing,PNDBPR）方案。该方案的实施过程为利用随机数机制计算幻影节点的随机有向游走跳数,通过该机制可以增加幻影节点的位置分布多样性与动态性,经概率转发路由机制将数据包从幻影节点转发至汇聚节点,目的是降低重合路径产生的可能性。从隐私保护性能和通信开销两方面对 PNDBPR 方案和基于源节点有限洪泛的源节点隐私保护（source location pri-vacy preservation protocol in wireless sensor network using source-based restricted flooding,PUSBRF）方案进行了理论对比分析,并在 MATLAB 仿真平台上对 PNDBPR 方案与 PUSBRF 方案做了仿真分析。理论和仿真分析表明,PNDBPR方案产生的幻影节点位置分布更广泛,传输路径更复杂,增加了安全时间,能明显提高源节点位置隐私保护的安全程度。     

基于Hash链的移动自组织网匿名路由激励协议

为激励移动自组织网络中的自私节点参与数据转发,以改善路由机制性能,在基于地理位置的路由机制中,提出了一种基于Hash链的匿名路由激励协议。该协议将基于Hash链的微支付机制,引入位置辅助隐私保护路由;通过对匿名数据转发节点进行实时激励,改善了不可信环境下隐私保护路由机制的性能。安全性分析表明:该协议能保证参与路由节点的匿名性,同时有效抵御针对基于地理位置路由的伪装攻击和重放攻击。效率分析表明:该协议能实时激励匿名节点参与数据转发。     

位置隐私泄露的一种度量方法

现有的文献大都是对位置隐私保护算法的研究,对于位置隐私保护算法的隐私性度量的研究相对缺乏。为此,针对贪心法的位置K-匿名算法(Greedy-based Location K-anonymous Algorithm,GLKA)提出位置隐私泄露的度量方法。该方法以KL散度(Kullback-Leibler divergence)为基础,将攻击者的背景知识融入其中,用以度量匿名区域中用户位置隐私的泄露。仿真实验表明,该度量方法可以有效地度量攻击者在具有背景知识的情况下,用户位置隐私泄露的水平,从而为位置隐私保护算法的设计与实现提供一定的参考。     

基于匿名通信的在线匿名秘密交易协议

为了保护在线交易中购买方的隐私,提出了一种基于匿名通信的在线匿名秘密交易协议.供货方在公告板发布自己的商品信息,购买方利用基于随机转发的匿名通信模型发送订购信息给供货方.购买方利用混合加密算法将订购消息加密后,发送给网络中的随机选出的一个中转节点,该节点收到之后以概率P转发给随机选出的下一个中转节点,或者以概率1-P直接将消息发送给供货方.重复以上转发过程,直到消息最终到达供货方.供货方、中转节点和攻击者都不可能获取购买方的身份信息和位置信息.中转节点和攻击者都不能获取订购信息.该协议不依赖于特定的网络节点,因而能够有效地平衡网络负载,提高系统的稳定性和可靠性.试验结果表明该协议能够支持网络中多个购买方—供货方之间实现安全的、高效的在线匿名密码交易,而且具有较好的健壮性.     

一种基于隐私偏好的二次匿名位置隐私保护方法

针对基于位置的服务带来的用户位置隐私暴露问题,提出了一种基于隐私偏好的二次匿名位置隐私保护方法,融合k-匿名技术和差分隐私技术确保用户位置隐私,设计隐私等级划分策略,支持用户个性化设置隐私保护级别。根据隐私级别确定k匿名集大小,通过基于位置熵的k匿名算法求解k-1个匿名点,使k匿名集的点具有最大概率相似性;在此基础上进一步求解获取位置服务的匿名位置,提出了基于差分隐私的匿名位置生成算法,在保护用户位置隐私的同时确保获取精确的位置服务。实验结果表明在用户隐私等级设置范围内,所提方法能有效兼顾位置隐私保护和LBS服务质量。     

基于门限路由的源节点位置隐私保护协议

近年来,随着无线传感器网络在军事和医疗等领域的应用越来越多,无线传感器网络的隐私保护研究受到了人们的广泛关注.本文提出了一种门限路由的源节点位置隐私保护协议(Threshold Routing for Source-Location Privacy Protection,TR),与已存在的源位置隐私保护协议不同,该协议可以提供更高效的隐私保护能力和有效地降低能量的消耗.应用NS2进行模拟仿真实验,结果表明与其他的隐私保护协议相比,门限路由协议在能耗和隐私保护方面具有更好的性能.     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

Perspherical Approaches for Electrons in Atoms and Charged Excitons in Quantum Wells

Instead of following Fock’s expansion,we solve the Schrodinger equation for some quantum mechanical manybody systems such as electrons in atoms and charged excitons in quantum wells in a similar way in hyperspherical coordinates by expanding the wave functions into orthonormal complete basis sets of the hyperspherical hannonics(HHs)of hyperangles and generalized Laguerre polynomials(GLPs)of the hyperradius.This leads the equation to     

Advances in broadband wireless communications under high-mobility scenarios

Future mobile communication systems aim at providing very high data transmission rates, even in high-mobility scenarios such as high-speed wheel-track trains, maglev trains, highway vehicles, airplanes, guided missiles or spacecraft. A particularly important commercial application is the strong and increasing worldwide demand for high- speed broadband wireless communications （up to 574.8 km/ h test speeds or 380 km/h commercial speeds） in railways, providing data, voice and video services for applications such as onboard entertainment services to passengers, train control, train dispatch, train sensor status handling and sur- veillance. In such high-mobility scenarios, there are a number of communication challenges, including fast hand- over, location updating, high-speed channel modeling, estimation and equalization, anti-Doppler spreading tech- niques, fast power control, and dedicated network architec- ture. Because signal transmission in very high-speed scenarios will inevitably experience serious deterioration, it is imperative to develop key broadband mobile communi- cation techniques for such high-speed vehicles.     

Wuhan University Journal of Natural Sciences TOTAL CONTENTS

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海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。     

Scale-based spatial data model for GIS

Being the primary media of geographical information and the elementary objects manipulated, almost all of maps adopt the layer-based model to represent geographic information in the existent GIS. However, it is difficult to extend the map represented in layer-based model. Furthermore, in Web-Based GIS, It is slow to transmit the spatial data for map viewing. In this paper, for solving the questions above, we have proposed a new method for representing the spatial data. That is scale-based model. In this model we represent maps in three levels: scale-view, block, and spatial object, and organize the maps in a set of map layers, named Scale-View, which associates some given scales.Lastly, a prototype Web-Based GIS using the proposed spatial data representation is described briefly.     

Exciton Seebeck in Molecular Systems

Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with     

Achieving Unusual States of Matter Under High Pressure

The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to