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61.
Inspired by the promising potential of re-configurable intelligent surface (RIS)-aided transmission in achieving the vision of 6th Generation (6G) network, we analyze the security model for a vehicular-to-infrastructure (V2I) network by considering multiple RISs (M-RIS) on buildings to act as passive relays at fixed distances from a source. In addition, multiple eavesdroppers are presented in the vicinity of the intended destination. Our aim is to enhance the secrecy capacity (SC) and to minimize secrecy outage probability (SOP) in presence of multiple eavesdroppers with the help of M-RIS in V2I communications. We propose a key-less physical layer security using beam-forming by exploiting M-RIS. The proposed approach assumes the concept of detecting eavesdroppers before the information can be transmitted via beam-forming by utilizing M-RIS. The results reveal that with consideration of M-RIS and beam-forming, the achievable SC and SOP performance is significantly improved while imposing minimum power consumption and fewer RIS reflectors.  相似文献   
62.
针对网络安全评估存在的不确定性,提出了一种新的基于区间层次分析法的网络安全评估方法.首先建立了多层次的网络安全评估指标体系,然后利用区间层次分析法确定了网络安全评估指标的区间数权重.在此基础上,结合区间数理论建立了基于区间层次分析法的网络安全评估模型.最后结合评估实例对某公司办公自动化网络进行了安全评估,验证了方法的可行性和有效性.  相似文献   
63.
With the emergence of wireless networks, cooperation for secrecy is recognized as an attractive way to establish secure communications. Departing from cryptographic techniques, secrecy can be provided by exploiting the wireless channel characteristics; that is, some error-correcting codes besides reliability have been shown to achieve information-theoretic security. In this paper, we propose a polar-coding-based technique for the primitive relay wiretap channel and show that this technique is suitable to provide information-theoretic security. Specifically, we integrate at the relay an additional functionality, which allows it to smartly decide whether it will cooperate or not based on the decoding detector result. In the case of cooperation, the relay operates in a decode-and-forward mode and assists the communication by transmitting a complementary message to the destination in order to correctly decode the initial source’s message. Otherwise, the communication is completed with direct transmission from source to the destination. Finally, we first prove that the proposed encoding scheme achieves weak secrecy, then, in order to overcome the obstacle of misaligned bits, we implement a double-chaining construction, which achieves strong secrecy.  相似文献   
64.
随着信息化的发展,信息安全得到前所未有的重视,国家主管机构的监管越来越严厉,企业在面临强制压力的合规性问题时可以选择自行部署,也可以选择服务外包.通过建立数学模型模拟了这个过程.分析结果表明:在强制压力情况下,如果用户选择外包方式,那么用户信息系统的期望值随着强制压力的提高而降低,信息安全服务供应商的利润则随着强制压力的提高而提高.  相似文献   
65.
A straightforward, cost effective and eco-friendly protocol for the Biginelli reaction relying on the use of readily available hypophosphorous acid is presented. The methodology developed displays improvements compared to existing methods, is high-yielding, robust and was applied to a panel of dihydropyrimidines and thio-derivatives with various substituents. Related urea derivatives such as guanidines, benzimidazoles and benzothiazoles also reacted efficiently to afford more complex scaffolds. Thus, this rapid and convenient catalysis allows access to a wide diversity of structures including original biologically relevant heterocycles.  相似文献   
66.
In order to contribute to the valorisation of wild fungi whose nutritional potential, although considerable, is not sufficiently known in some countries such as Togo, a study has been carried out on Russula species. The diversity of Russula species from Alédjo Wildlife Reserve has been assessed using a focused inventory in woodlands dominated by Isoberlinia doka Craib & Stapf, Isoberlinia tomentosa (Harms) Craib & Stapf, Monotes kerstingii Gilg, Uapaca togoensis Pax and gallery forests dominated by Berlinia grandiflora (Vahl) Hutch & Dalz and Uapaca guineensis Müll. Ethnomycological surveys have been carried out among Tém and Kabyè, two riparian ethnic groups that are mainly represented. Biochemical analyses have been carried out using the AOAC method. Fifteen (15) taxa of edible Russula species are commonly used by Tém and Kabyè people living along the Alédjo Wildlife Reserve among which thirteen (13) taxa have been identified up to species level. R. oleifera is eaten by all interviewed people in both sociolinguistic groups (Fr = 100%) followed by R. compressa (Fr = 92.31%), R. ochrocephala (Fr = 87.18%) among Tém people and R. ochrocephala (Fr = 91.67%), R. compressa (Fr = 83.33%) among Kabyè people. Five (05) new species of edible Russula have been identified for the first time in Togo. The Russula species analysed have been rich in macronutrients with contents ranging from 2.88 g/100 g of dw for fat to 65.83 g/100 g of dw for total carbohydrates. In addition, these Russula species have shown a relatively high mineral content with contents ranging from 405.70 mg/100 g of dw for Ca to 2784 mg/100 g of dw for K. Furthermore, the results have revealed that Russula species analysed are a source of energy with 309.50 Kcal/100 g of dw. The edible Russula species analysed can thus contribute to food security in Togo.  相似文献   
67.
该文对苯二氮类和吩噻嗪类镇静安眠药样品的红外光谱数据进行采集,构建了不同数据分类模型并对比了不同波段光谱数据集对其分析准确率的影响。结果表明,借助贝叶斯判别分析的基于全波段数据集的二阶导数模型分类效果优于其他单一模型,对于苯二氮类和吩噻嗪类两个不同类型精神药物的总体分类准确率达92.7%。借助贝叶斯判别分析的基于全波段和指纹区融合数据集的二阶导数融合模型分类效果最佳,对苯二氮类和吩噻嗪类两个不同类型精神药物的总体分类准确率达到100%;对苯二氮类和吩噻嗪类中不同种类精神药物的总体分类准确率则分别达到96.7%和100%。该研究实现了不同类型及同一类型不同种类镇静安眠药的快速准确定性分析,为此类管制类药物走私案件的准确定性提供了一定的技术支持。  相似文献   
68.
Electrocatalytic oxidation of 5-hydroxymethylfurfural (HMF) offers a renewable approach to produce the value-added platform chemical 2,5-furandicarboxylic acid (FDCA). The key for the economic viability of this approach is to develop active and selective electrocatalysts. Nevertheless, a reliable catalyst evaluation protocol is still missing, leading to elusive conclusions on criteria for a high-performing catalyst. Herein, we demonstrate that besides the catalyst identity, secondary parameters such as materials of conductive substrates for the working electrode, concentration of the supporting electrolyte, and electrolyzer configurations have profound impact on the catalyst performance and thus need to be optimized before assessing the true activity of a catalyst. Moreover, we highlight the importance of those secondary parameters in suppressing side reactions, which has long been overlooked. The protocol is validated by evaluating the performance of free-standing Cu-foam, and CuCoO modified with NaPO2H2 and Ni, which were immobilized on boron-doped diamond (BDD) electrodes. Recommended practices and figure of merits in carefully evaluating the catalyst performance are proposed.  相似文献   
69.
70.
For the first time, an efficient, simple, synthetic green protocol for the one-pot synthesis of functionalized 2-oxo-benzo[1,4]oxazines 2429 in water under ultrasound irradiation is presented. As compared to conventional methods, the present protocol avoids traditional chromatography and purification steps and furnished the target molecules in excellent yields (upto 98%) with no side products. The methodology was also demonstrated on gram scale synthesis. Moreover, functionalized 2-oxo-quinoxaline analogues 3133, another class of bio-active heterocyclic scaffolds, were also prepared using this method. For the first time, this protocol was successfully applied in the synthesis of the anticancer indole alkaloid, Cephalandole A 35.  相似文献   
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