边防视频监控系统建设思考

视频监控系统在当今社会中发挥着重要作用,目前已广泛应用到各领域.考虑其在边境防御和边防管控中的特殊作用,结合近年来的工作实践,对地级、县级监控中心,以及监控站视频监控系统的设计原则、功能设置进行分析,提出建设中应把握好的几个问题,供相关部门建设时借鉴参考.     

战术数据链网络的介质访问控制层优化控制及性能分析

为解决战术数据链中优先级问题,提出一种基于完全接入策略和非对称门限接入策略的区分优先级两级轮询控制策略,用于战术数据链网络的媒体接入控制中。在该轮询控制策略中,对战术数据链中的低优先级前哨站点采用非对称门限接入策略,对高优先级前哨站点采用完全接入策略;在网络控制站点由高优先级前哨站点转低优先级前哨站点时,将传输服务与转移查询并行处理来降低查询转换期间所耗费的时间,提高轮询系统的效率。运用马尔可夫链和概率母函数方法建立了系统的数学模型,精确解析出各个前哨站点内等待发送的平均信息分组数表达式。结合循环周期2阶特性量近似方法,解析出前哨站点内信息分组平均等待发送时间的近似表达式。仿真实验结果表明,实验值与理论值大致相等且高优先级前哨站点的服务质量优于其他站点,证明理论分析正确,该模型达到了区分优先级的目的。     

Energy Efficient Cluster Based Routing Protocol for WSN Using Firefly Algorithm and Ant Colony Optimization

Maximizing network lifetime is the main goal of designing a wireless sensor network. Clustering and routing can effectively balance network energy consumption and prolong network lifetime. This paper presents a novel cluster-based routing protocol called EECRAIFA. In order to select the optimal cluster heads, Self-Organizing Map neural network is used to perform preliminary clustering on the network nodes, and then the relative reasonable level of the cluster, the cluster head energy, the average distance within the cluster and other factors are introduced into the firefly algorithm (FA) to optimize the network clustering. In addition, the concept of decision domain is introduced into the FA to further disperse cluster heads and form reasonable clusters. In the inter-cluster routing stage, the inter-cluster routing is established by an improved ant colony optimization (ACO). Considering factors such as the angle, distance and energy of the node, the heuristic function is improved to make the selection of the next hop more targeted. In addition, the coefficient of variation in statistics is introduced into the process of updating pheromones, and the path is optimized by combining energy and distance. In order to further improve the network throughput, a polling control mechanism based on busy/idle nodes is introduced during the intra-cluster communication phase. The simulation experiment results prove that under different application scenarios, EECRAIFA can effectively balance the network energy consumption, extend the network lifetime, and improve network throughput.

     

基于现场可编程门阵列战术数据链中自适应轮询接入控制协议的设计与实现

在战术数据链系统中,战术单元随时都有可能被摧毁而引起网络拓扑结构动态变化,导致系统服务效率降低。为了解决这一问题,基于动态调整轮询顺序的思想,提出一种自适应轮询接入控制协议（APACP）。采用概率母函数的方法和嵌入式马尔可夫链理论对系统进行建模,得到系统平均排队队长和平均轮询周期的解析解;利用数学软件MATLAB和现场可编程门阵列仿真验证协议的正确性。仿真结果表明,APACP能够根据战术数据链网络拓扑结构的动态变化自动调整轮询顺序,明显降低系统平均排队队长和平均轮询周期,克服传统轮询接入控制协议中空轮询的问题,节约了服务时间,提高了服务效率,改善了系统性能。     

Corrosion Behavior of TiC Particle‐Reinforced 2Cr13 Stainless Steel

The corrosion behavior of TiC particle‐reinforced 2Cr13 stainless steels prepared by in situ reaction and electroslag remelting (ESR) was investigated using potentiodynamic polarisation measurements and immersion tests. The addition of TiC particles to 2Cr13 stainless steel impeded rapid pit propagation but maintained a high corrosion rate in the whole immersion time investigated. The TiC addition developed finer matrix structure, the formation of Cr‐rich carbides and high dislocation density around the TiC particles before corrosion, which results in an increasing corrosion rate and preferential pitting attack at the steel matrix/TiC interface. Although the corrosion resistance of 2Cr13 stainless steel is sharply decreased due to TiC addition, it is significantly improved after the ESR process. This is attributed to the more uniform distribution and smaller size of TiC particles, the increase of value of χ in TiCχ and the elimination of the porosity in TiC particle‐reinforced 2Cr13 stainless steel after the ESR process.     

近地表空间梯度瞬变电磁粒子群优化反演研究

空间梯度瞬变电磁测量方法利用以发射线圈为对称平面的两个同规格接收线圈信号相减,消除了一次场互感影响,使得早时段瞬变电磁响应得到精确测量,为近地表电性结构层探测提供技术支持.瞬变电磁法一维正演理论研究表明:相比于重叠回线装置,空间梯度瞬变电磁观测模式在早时段(1 ms内)记录具有优势,对近地表30 m深度范围内的介质地电...     

磷石膏基矿井充填材料制备及其性能研究

为实现磷石膏的资源化利用,制备了以原状磷石膏为主要原料、赤泥为碱性激发剂的矿井充填材料,并分析了高效减水剂掺量、水泥掺量、赤泥掺量对其性能的影响。实验结果表明,水灰质量比为0.2,聚羧酸盐减水剂掺量为0.5%（质量分数）时,浆料的初始流动度约为230 mm,满足充填材料性能要求;水泥掺量从0增加到10%时,28 d抗压强度从2.03 MPa提升至10.75 MPa,初始流动度从180 mm增加到235 mm,强度保持率从0.39提升至1,表明水泥掺量直接影响充填材料的强度、流动性及耐水性能;赤泥掺量从0增加到5%时,28 d抗压强度提升了50%,强度保持率从0.82提升至1,激发作用明显,对材料的流动性有相反的影响。     

聚氯乙烯用热稳定剂研究现状及发展态势

聚氯乙烯（PVC）具有价廉,难燃,耐腐蚀性和透明性好等优点。但其稳定性差,在外界因素如热、光、氧及力的作用下易发艇分解和交联反应,致使PVC的加工和使甩困难。因此,开发有效的热稳定剂对发展PVC工业具有重要意义。文章介绍了聚氯乙烯（PVC）热稳定剂研究现状,并对聚氯乙烯热稳定剂的应用前景进行了展望。     

变化环境下鄱阳湖洪水指标演变特征研究

本文基于鄱阳湖洪水特点,选取特定洪水特征指标,利用数理统计方法分析鄱阳湖洪水特征指标的趋势性、突变性和周期性,并分析演变特征和驱动因素,得到结论如下：1）未来高洪可能性仍然较大,未来6～10a鄱阳湖年最高水位仍处于丰水期;2）洪水在年内分配发生较大改变,变化过程从“矮胖型”向相对“尖瘦型”演变,水量在年内更加集中化;3）高洪持续天数显著增加,19.00m以上的高水位维持时间平均每10a延长2.2d;4）年最高水位及年平均水位周期性变化主要受“五河”入湖周期性变化所控制,同时会受到其他因素影响而改变原有周期性变化规律,年最高水位具有5a为第一主周期,40～49a为第二主周期的变化规律。