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1.
针对传统的基于分簇的无线传感器网络(WSNs)信任评价模型中,簇头节点因负担大量的计算工作而降低网络生存时间的问题,提出一种通过人工免疫评估WSNs中节点信任值的方法。该方法运用阴性选择算法产生检测器,由基站根据检测器进行节点的信任检测,不需要簇头节点聚合成员节点的信任值,只要求簇头节点将成员节点的信任属性发送给基站,降低了簇头节点的负担,延长了WSNs的生存时间。仿真实验结果表明,该方法在延长网络生存时间的同时,与已有方法相比具有较高的检测率,在非信任节点数不超过40%时,检测率高于90%。  相似文献   

2.
针对传统的基于分簇的无线传感器网络(WSNs)信任评价模型中,簇头节点因负担大量的计算工作而降低网络生存时间的问题,提出一种通过人工免疫评估WSNs中节点信任值的方法。该方法运用阴性选择算法产生检测器,由基站根据检测器进行节点的信任检测,不需要簇头节点聚合成员节点的信任值,只要求簇头节点将成员节点的信任属性发送给基站,降低了簇头节点的负担,延长了WSNs的生存时间。仿真实验结果表明,该方法在延长网络生存时间的同时,与已有方法相比具有较高的检测率,在非信任节点数不超过40%时,检测率高于90%。  相似文献   

3.
限于高度开放、节点众多且资源严重不足等因素,无线传感网(wireless sensor network,WSN)的安全管理面临着巨大挑战。提出了一种基于骨干节点安全角色层级化的WSN安全模型,通过遴选安全管理节点,划分子网的方式实现能量优化以及节点信任管理,从能效和安全角度提升网络性能。仿真测试结果表明,该方案在强化WSN安全性的同时,仍可节省约25.9%的网络能量消耗,且随着网络规模的扩大其优势将更加明显,为提升WSN的安全管理效率提供了可行的新思路。  相似文献   

4.
针对现有的特征选择算法和分类算法在无线传感器网络(WSN)入侵检测系统中检测性能表现不佳、检测实时性差、模型复杂度高等问题,提出一种基于随机森林和深度森林算法的分布式WSN入侵检测模型.该模型首先对传感器节点流量数据进行预处理;然后将轻量级随机森林分类器部署到传感器节点和簇头节点,传感器节点和簇头节点合作对流量数据进行处理,并在基站上采用深度森林算法从大量流量数据中发现攻击行为;最后对WSN中的入侵行为进行实时分类入侵检测.使用无线传感器数据集WSN-DS和NSL-KDD数据集来评估所提出的模型性能.实验结果表明,该模型与现有的入侵检测模型相比,具有良好的检测性能,实时性较高,可避免模型过度拟合.  相似文献   

5.
针对点对点网络节点信任关系以及交易可能性较小的特点,阐述基于核心节点的点对点信任网络模型.该网络模型中的网络节点以公有度和私有信任度进行聚类,依靠节点可靠度针对核心节点和普通节点分情况讨论,并给予相关解决方案.仿真实验结果表明:该信任模型不但具有抗恶意节点攻击的鲁棒性,同时在网络资源搜索时具有较低的评估计算量和通信开销.  相似文献   

6.
平衡理论的P2P网络分布式信任模型   总被引:1,自引:1,他引:0  
当前P2P网络中存在着大量的恶意节点攻击和共谋团体欺骗等问题,已存在的信任模型一定程度上完善了P2P网络环境,但模型的侧重点不同,无法全面解决大规模的恶意攻击和欺骗。为此,提出了基于平衡理论的P2P信任模型。该模型由信任结构的构建、恶意节点检测和信任推测等3部分完成。模型根据平衡理论构建信任网络;针对恶意节点的攻击,利用平衡理论定义节点的平衡因子,通过计算恶意行为对网络平衡性的影响来检测恶意节点;利用信任推测算法来推测信任节点,防止网络加入不信任的节点,降低网络的安全性。实验结果表明该模型可靠完善,算法有效和健壮。  相似文献   

7.
当前P2P网络中存在着大量的恶意节点攻击和共谋团体欺骗等问题,已存在的信任模型在一定程度上完善了P2P网络环境;但模型的侧重点不同,无法全面解决大规模的恶意攻击和欺骗。为此,提出了基于平衡理论的P2P信任模型。该模型由信任结构的构建、恶意节点检测和信任推测等三部分完成。模型首先根据平衡理论构建信任网络;针对恶意节点的攻击,利用平衡理论定义节点的平衡因子,通过计算恶意行为对网络平衡性的影响来检测恶意节点;最后利用信任推测算法来推测信任节点,防止网络加入不信任的节点,降低网络的安全性。实验结果表明该模型可靠完善,算法有效和健壮。  相似文献   

8.
通过区间型联系数建立决策模型是解决多属性决策问题,具有方法简单、计算量小的特点,非常契合无线传感器网络资源受限的特点。针对无线传感器网络中路由能量消耗不平衡,提出一种基于区间型联系数的无线传感器网络(wireless sensor network,WSN)路由选择方法,对节点剩余能量、可靠性、方向、邻居节点个数等多属性进行综合评价,利用相对贴近度进行排序选择转发节点,并在属性决策中利用熵权法对多评价目标因子赋权,以避免属性权重选取时的主观性,最终形成路由路径。仿真结果验证了该算法在平衡网络能耗、延长网络生存时间等方面表现出良好的性能  相似文献   

9.
由于无线传感器网络(Wireless Sensor Network,WSN)需要进行大量的信息采集传输工作,如何确保网络的安全一直是WSN面临的主要问题.将最新的自防御网络(Self-Defending Network,SDN)技术与入侵检测技术相融合,提出一种更有效的入侵检测方案.该方案充分利用了SDN架构的特点和网络所特有的自相似特点,能够及时判断WSN中是否有节点遭到入侵,极大程度上解决了普通节点能量和计算能力不足等缺陷.不仅如此,该检测方案能够根据WSN的环境进行灵活的部署,保障了检测方案的多样性,以及针对WSN遭受到的入侵主动做出响应,提高了安全性.  相似文献   

10.
基于量子遗传算法的无线传感网络路由优化   总被引:1,自引:0,他引:1  
考虑到无线传感网络(WSN)传感器节点的能量有限性,分析了WSN的网络模型和能量模型,提出一种基于改进量子遗传算法的路由优化算法.利用复杂连续函数测试,验证了算法的性能和可行性.经仿真分析,证明该算法应用于WSN路由优化问题时,能更快速和更稳定地求解最小能量代价的数据传输路径,从而减少WSN传感器节点的能量消耗,延长整个WSN网络的使用寿命.  相似文献   

11.
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.  相似文献   

12.
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.  相似文献   

13.
王慧 《科技信息》2008,(10):240-240
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.  相似文献   

14.
何延凌 《科技信息》2008,(4):258-258
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.  相似文献   

15.
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.  相似文献   

16.
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.  相似文献   

17.
以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.  相似文献   

18.
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。  相似文献   

19.
Quality traits in wheat (Triticum aestirum L.) were studied by quantitative trait locus (QTL) analysis in a recombinant inbred line (RIL) population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross (ChSh). Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.  相似文献   

20.
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.  相似文献   

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