Accurate and energy-efficient boundary detection of continuous objects in duty-cycled wireless sensor networks

With the development and wide adoption of industrial wireless sensor networks to support various domain applications, the boundary detection of continuous objects has become an important research challenge, where improving the accuracy of boundary area while reducing the energy consumption are the first-class citizens to be considered. To address this research challenge, this article proposes a two-stage boundary face detection mechanism, where sensor nodes are duty-cycled and to be deployed in a dense fashion. When the occurrence of potential events are recognized using the initially activated sensor nodes, the boundary faces of continuous objects are constructed through adopting planarization algorithms. Thereafter, sensor nodes contained in certain boundary faces are examined, where their sensory data are estimated using spatial interpolation methods. Certain sensor nodes are selected to be woken up, only when their sensory data suggest that they should be more appropriate candidates of boundary sensor nodes. Consequently, the size of boundary faces is reduced, and this coarse-to-fine refinement procedure iterates, until all sensor nodes contained in the boundary faces have been examined. Experimental evaluation result shows that the boundary area can be refined significantly and be more precise, where the half of the initial boundary face area should be reduced in most situations.     

本科信息安全专业建设的实践与探索

本文分析了信息安全专业建设的现状和存在的问题,并根据我校该专业建设的实践提出了相关建议,对信息安全学科建设具有一定的指导作用。     

Ti/Ni多层复合材料界面扩散行为的研究

本文针对累积叠轧5道次制备的Ti/Ni多层结构复合材料试样进行热处理,采用光学显微镜和扫描电镜分析方法,对复合材料的显微组织、界面结构和扩散反应层厚度等进行观察分析,结合动力学理论研究了Ti/Ni界面的扩散行为。研究结果表明：试样经过累积叠轧5道次轧制后,Ti/Ni界面未发生扩散;在(550 ℃-750 ℃)×(0.5 h-8 h)热处理后,Ti/Ni界面发生扩散,扩散层厚度与保温时间呈幂函数关系,与加热温度呈指数关系;随着热处理温度的升高,Ti-Ni扩散层的生长方式由650 ℃以下的体扩散控制逐渐转变为晶界扩散控制。通过计算和验证得到采用累积叠轧5道次制备的Ti/Ni多层复合材料的Ti/Ni界面固相反应层生长动力学方程为：y=1.7043*104*exp(-78202/RT) *t1.2009-0.0008T。