Survivability-oriented optimal node density for randomly deployed wireless sensor networks

The survivability is usually critical for wireless sensor networks,which are often deployed in the unattended harsh environment.Lots of technical schemes to improve the survivability depend on the redundant resources of the sensor networks.The amount of resources is usually determined by the node density during the deployment phase.For the random deployment and random node failures,the quantitative relation between the survivability and the node density is studied.Based on the conditional survivability,the node density to meet the required survivability level is presented.Finally,the survivability for unpredictable failures and the optimal node density to maximize the price–performance ratio are also discussed.     

Promotion of hydrogen permeation on metal-dispersed alumina membranes and its application to a membrane reactor for methane steam reforming

A mesoporous membrane for selective separation of hydrogen was prepared usingthe sol-gel method. Some metal salts such as RuCl₃, Pd(NH₃)₄Cl₂, RhCl₃,, and H ₂PtCl₆, were added to the boehmite sol and coated on a porous alumina substrate before firing at 500°C. It was foundthat the permeability of hydrogen and the separation factor for a hydrogen-nitrogen gaseous mixture of these metaldispersed membranes exceeded the limitations of the Knudsen diffusion mechanism. Although the gas permeation through a neat alumina membrane is governed by the Knudsen diffusion, the metals dispersed in alumina membranes were effective in promoting hydrogen permeation. These metaldispersed alumina membranes were also used in a membrane reactor for methane steam reforming at low temperature. In the temperature range of 300 to 500°C, the membrane reactor attained a methane conversion twice as high as the equilibrium value of the packed bed catalytic reactor system as a result of the selective removal of hydrogen from the reaction system.     

The Utility of Information Security Training and Education on Cybersecurity Incidents: An empirical evidence

As recent cyber-attacks have been increasing exponentially, the importance of security training for employees also has become growing ever than before. In addition, it is suggested that security training and education be an effective method for discerning cyber-attacks within academia and industries. Despite the importance and the necessity of the training, prior study did not investigate the quantitative utility of security training in an organizational level. Due to the absence of referential studies, many firms are having troubles in making decisions with respect to arranging optimal security training programs with limited security budgets. The main objective of this study is to find out a relationship between cybersecurity training and the number of incidents of organizations. Thus, this study quantified the effectiveness of security training on security incidents as the first study. This research examined the relationship among three main factors; education time, education participants, and outsourcing with numbers of cybersecurity incidents. 7089 firm level data is analyzed through Poisson regression method. Based on analysis results, we found that the negative relationship between security trainings and the occurrence of cybersecurity incidents. This study sheds light on the role of security training and education by suggesting its positive association with reducing the number of incidents in organizations from the quantitative perspective. The result of this study can be used as a referential guide for information security training decision-making procedure in organizations.

     

Anti-BlUFf: towards counterfeit mitigation in IC supply chains using blockchain and PUF

International Journal of Information Security - The complexity of today’s integrated circuit (IC) supply chain, organised in several tiers and including many companies located in different...     

Bimodal plate structures induced by pulsed laser in duplex-phase Zr alloy

A duplex-phase Zr-2.5Nb alloy was treated by pulsed laser, followed by careful microstructural characterization using field emission gun scanning electron microscope and attached electron backscatter diffraction. Beneath the modification zones with common uniform α-plate structures(UPS), a layer of unreported bimodal α-plate structures(BPS) featured by coarse(submicron)plates forming multiple cores surrounded by dense fine(nanoscale) plates was found. Presence of such BPS is attributed to non-equilibrium thermodynamic conditions induced by the pulsed laser treatments. Limited diffusion of Nb due to the short pulse during laser heating allows β phases with distinctly different Nb contents to be presented: Nb-enriched prior β films and Nb-depleted β phases, transforming into the fine and the coarse plates during cooling, respectively. Orientation analyses show that both types of plates in the BPS are aroused essentially from a single β orientation, suggesting epitaxial growth of the Nb-depletedβ phases from the preexisting β films.     

基于溶剂沥青的冷再生沥青混合料性能评价

传统的沥青混合料冷再生技术有乳化沥青和泡沫沥青冷再生,本研究尝试采用所开发的溶剂沥青作为结合料对废旧沥青混合料进行冷再生,提出了试件的成型和养生方法,进行了配合比组成设计并采用热拌沥青混合料的标准对溶剂沥青冷再生混合料的性能进行评价.试验结果表明,溶剂沥青冷再生混合料的水稳定性能、高温稳定性能均满足我国热拌改性沥青混合料规范的性能要求,低温性能虽然不满足改性沥青混合料的要求,但能满足普通沥青混合料规范的性能要求.     

瞬变电磁法及高密度电法在采空区探测中的应用

采空区的存在严重威胁着人们正常的生产生活,为了防止采空区塌陷引起地面塌陷、房屋断裂等,必须在建设之前查明采空区的范围及塌陷密实程度,采用瞬变电磁法与高密度电法在测区内进行综合探测。本文介绍了瞬变电磁法和高密度电法的基本原理和数据处理流程,通过实例探讨了两种方法在采空区中的探测效果。     

改进互联通信荷电状态下垂控制及功率均衡优化

作为直流微电网中不可或缺的组成部分,分布式直流储能系统起着平抑系统能量波动、维持系统功率平衡的重要作用.为了提高储能系统工作的可靠性,该文对互联通信荷电状态(SOC)下垂控制策略进行深入研究.首先,对传统互联通信SOC下垂控制的系统性能及存在的问题进行分析,为之后控制策略的改进奠定基础;其次,提出改进互联通信SOC下垂控制策略,即在传统互联通信SOC下垂控制基础上引入变化系数;再次,通过对改进互联通信SOC下垂控制系统性能的分析,得到变化系数参数设计方法,在提高系统功率收敛速度的同时,限制功率输出最大值,从而提高系统可靠性;最后,对由两台储能模块构成的储能系统进行仿真和实验,实验结果验证了改进策略的快速性及对输出功率的限制.     

配电变压器低压隔离开关柜内母线短路监测研究

开关柜的故障会造成整个电力系统的不稳定,通过监控开关柜内的母线短路情况,可以有效降低故障的发生概率.采用红外测温的方式,对开关柜内的母线进行检测,在不影响系统稳定的前提下,提高了温度测量的准确性.采用LSTM算法结合小波变换的算法,在母线短路的判断上综合考虑了历史数据的影响,提高了判断的精准度.通过试验对算法进行验证,结果证明了方法的优越性.     

原位TiB2颗粒增强铝基复合材料形核机制及转变动力学

阐述原位合成制备TiB2颗粒增强铝基复合材料自生相的形核机制以及转变动力学，从热力学和动力学的一般角度来分析TiB2的形成机制，并讨论TiB2转变动力学。