一种高连通率的传感器网络密钥预分配方法

密钥管理是无线传感器网络安全的基础,其中密钥预分配是可行性比较高的密钥管理方法,节点之间的共享密钥的概率一直是密钥预分配中比较重要的性能指标,可是现有的无线传感器网络密钥预分配方案大多存在节点间密钥共享概率低或者共享概率不稳定的问题.结合Blom对称多项式,通过改进TD方法,提出了一种改进的密钥预分配方法,该方法能够实现稳定的节点间高密钥共享概率,从而保证了无线传感器网络的安全连通,此外该方法还具有灵活易变的特性,可以改变传感器分组数目以及传感器存储的密钥个数,满足实际需求.     

异构无线传感器网络动态混合密钥管理方案研究

在需要进行安全通信的无线传感器网络应用中,复杂的公钥系统难以在资源有限的传感节点上实现,而基于随机预分配的对称密钥系统有节点连通性不强、密钥存储空间过大、密钥协商过程复杂且不灵活等问题。因此,在异构无线传感器网络基础上,提出一种联合公钥机制与私钥机制的混合密钥管理方案(DHKAS)。该方案使用一种简便可靠的方法,以较小的代价解决了密钥管理中最关键的节点认证问题。分析结果显示,所提方案有效提高了节点的连通性、减少了密钥存储空间,并增强了网络抗攻击能力。     

一种无线传感器网络组播密钥管理方案

在无线传感器网络中,为了得到所监测区域的准确信息,保护节点间进行安全通信至关重要,因此,针对现存方案的不足,提出一种基于分组的密钥管理方案,节点部署后,实现了节点间通信密钥的建立,分析结果表明,该方案适用于大规模的无线传感器网络,在保证节点间安全通信的同时,提高了网络的连通性.     

基于密钥池的簇状传感器网络动态密钥分配协议

为了解决簇状传感器网络中的密钥分配问题，在分析传感器网络的基本密钥预分配机制的基础上，提出了基于密钥池的簇状网络动态密钥分配协议．在保证网络连通率相同的情况下，该协议与基本机制最大的区别在于，网络节点能逐层从基站随机选取不同大小的密钥环．动态分配协议经过初始化、密钥建立和路径密钥建立3个阶段，使整个传感器网络形成一个由安全链路构成的连通图，而簇内同层节点以及相邻层间节点可以通过安全链路进行通信，协同完成应用任务．通过分析和实验证明，所提协议可有效节省存储空间达50%以上，并能显著提高网络抵御攻击的能力．     

基于椭圆曲线的无线多媒体传感器网络安全密钥预分配方案

随着物联网应用的兴起,将有越来越多的隐私信息通过多媒体传感器进行传输,因此,必须对多媒体传感器节点之间的通信加以保护,以达到隐私保护的目的。文中提出一种基于椭圆曲线的无线多媒体传感器网络的安全密钥预分配方案,它利用椭圆曲线上的不同基点作为种子密钥,并基于种子密钥进行倍点运算生成私钥环,该私钥环在节点部署之前被分配给每个传感器节点,通过选择合适的私钥环大小,两个相邻节点共享相同私钥的可能性高,其他不共享私钥的相邻节点亦可通过路径密钥经由中间节点实现安全通信,从而保障整个传感器网络的隐私通信安全。仿真结果表明,该方案具有较好的网络连通性和防御性。     

一种无线传感器网络密钥动态预分配策略

为了实现无线传感器网络中的安全通信，传感器结点间传递的信息就必须被加密和认证.所以密钥分配与管理就成为基本问题之一.分析了随机对密钥预分配策略的不足，将其与基于配置信息的密钥预分配策略相结合并进行改进，提出了一种新的密钥动态预分配策略.     

一种基于位置信息的WSN随机密钥预分配方法

基于随机密钥预分配方案(KPS),提出了一种基于位置信息的随机密钥预分配方案(PKPS),此方案通过使用位置信息和优先级划分的方法,提高了邻居节点拥有相同密钥的概率,从而提高了节点能够安全通信的概率.文中详细介绍了此方案的具体内容,并对它的性能做了详细的分析.分析结果表明,与随机密钥预分配方案相比,文中所提方案能大大改善无线传感器网络的各种性能,如通信负载、网络连通度、网络对于节点被俘获的抵抗性等.     

无线传感器网络安全加密成簇算法的设计及研究

在无线传感器网络中,网络节点的成簇算法是实现对传感器网络高效节能管理和应用的有效途径.为了提高网络的安全性和寿命,提出了一种基于随机并行簇头选举算法和密钥预分配方案,在假设的网络模型中,均匀地选举簇头节点,并且实现对恶意节点的识别和删除,在数据通信阶段通过加密算法实现数据通信的安全性,从而有效地实现网络寿命的延长和数据通信的安全.     

基于相邻节点协作的无线传感器网络安全协议

为了解决无线传感器网络(WSN)密钥管理与认证协议设计中节点频繁的信息交换所带来的能量消耗过大的问题,提出了一种基于相邻节点协作的改进型密钥分配方案.该方案在节点密钥建立过程中加入了相邻节点的相关信息,结合密钥预分配技术,在提高系统抗毁性的同时,进一步降低了节点密钥建立的通信成本.与LEAP、NEKAP进行比较,结果表明,密钥分配方案在安全认证、抵御重放攻击以及节能等方面更具优势.     

无线传感器网络安全加密成簇算法的设计及研究

在无线传感器网络中,网络节点的成簇算法是实现对传感器网络高效节能管理和应用的有效途径为了提高网络的安全性和寿命,提出了一种基于随机并行簇头选举算法和密钥预分配方案,在假设的网络模型中,均匀地选举簇头节点,并且实现对恶意节点的识别和删除,在数据通信阶段通过加密算法实现数据通信的安全性,从而有效地实现网络寿命的延长和数据通信的安全。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that