A Non-Line-of-Sight mitigation localization algorithm for sensor networks using clustering analysis

Non-Line-of-Sight propagation of wireless signal has an impact on measured distances in range-based localization and will bias the final localization results. A new localization algorithm is proposed in this paper to mitigate Non-Line-of-Sight errors when there are more than enough anchor nodes deployed around the node to be located. This algorithm utilizes multi-round clustering analysis to filter the pre-located estimators which derive from all possible subsets of measured distances. In each round, the method density-based spatial clustering of applications with noise is adopted. Simulations show that the proposed algorithm can effectively improve localization accuracy not only when the measured distances with Non-Line-of-Sight error are minor but also under the condition that all of them suffer random Non-Line-of-Sight error.     

Location allocation modeling for healthcare facility planning in Malaysia

Malaysia has seen tremendous growth in the standard of living and household per capita income. The demand for a more systematic and efficient planning has become increasingly more important, one of the keys to achieving a high standard in healthcare. In this paper, a Maximal Covering Location Problem (MCLP) is used to study the healthcare facilities of one of the districts in Malaysia. We address the limited capacity of the facilities and the problem is formulated as Capacitated MCLP (CMCLP). We propose a new solution approach based on genetic algorithm to examine the percentage of coverage of the existing facilities within the allowable distance specified/targeted by Malaysian government. The algorithm was shown to generate good results when compared to results obtained using CPLEX version 12.2 on a medium size problem consisting of 179 nodes network. The algorithm was extended to solve larger network consisting of 809 nodes where CPLEX failed to produce non-trivial solutions. We show that the proposed solution approach produces significant results in determining good locations for the facility such that the population coverage is maximized.     

Effect of Multi-Wall Carbon Nanotubes on the Mechanical Properties of Natural Rubber

Multi-walled carbon nanotubes (MWNTs) were used to prepare natural rubber (NR) nanocomposites. Our first efforts to achieve nanostructures in MWNTs/NR nanocomposites were formed by incorporating carbon nanotubes in a polymer solution and subsequently evaporating the solvent. Using this technique, nanotubes can be dispersed homogeneously in the NR matrix in an attempt to increase the mechanical properties of these nanocomposites. The properties of the nanocomposites such as tensile strength, tensile modulus, elongation at break and hardness were studied. Mechanical test results show an increase in the initial modulus for up to 12 times in relation to pure NR. In addition to mechanical testing, the dispersion state of the MWNTs into NR studied by Transmission Electron Microscopy (TEM) in order to understand the morphology of the resulting system     

高层结构风振性能水准的二级模糊综合评价研究

针对风振作用下高层结构的性能状态,引入模糊综合评价理论,研究了高层结构风振性能水准的评价因子,给出了上部结构、外部环境和地基与基础三类评价因子划分的等级标准,建立了高层结构风振性能水准预测的层次评价体系,提出了高层结构风振性能水准的二级模糊综合评价模型,并基于Matlab语言编制了结构风振性能模糊概率预测的计算程序。将所提模糊综合评价模型用于广州某四个高层结构风振性能水准的预测评价中,计算结果表明模糊综合评价模型可充分考虑影响结构风振性能水准的各种不确定信息,能根据权重系数的大小对所有评价因子的影响均衡兼顾,进而实现对高层结构的风振性能状态进行很好的预测;二级模糊综合评价模型能更加合理地考虑各评价因子的权重系数,计算结果优于一级模糊综合评价。研究结果可为工程结构抗风设计和加固改造提供参考指导。     

基于LSTM的阀冷系统入水温度及冷却裕度预测

为解决换流站阀冷系统状态缺乏智能预测手段和极端工况下冷却能力是否充裕难以评估的问题,提出基于长短期记忆网络(long short-term memory,LSTM)的换流阀冷却裕度预测方法.在阀冷系统冷却裕度指标量化评估的基础上,考虑多源影响因素,通过相关性强弱选择特征量并构建数据样本集,利用长短时记忆网络建立预测模型...     

光伏储能站能量调度管理策略

以低负荷时刻优先充电、高负荷时刻优先放电为原则,以削峰填谷为目的,实现极大化光伏发电利用率,建立了光伏储能站能量管理的数学模型。模型包括常规调度控制策略和紧急调度控制策略,常规调度可以实现无故障情况下的储能电池的充放电功率控制,紧急控制可以在电网故障情况下短时间内实现常规用户的用电需求。研究结果表明,光储一体调度管理策略可推迟设备容量升级提高系统调峰能力,提高电网经济效益。     

β-FeSi_2(n)/c-Si(p)HIT型太阳能电池的模拟与优化

运用afors-het软件对β-FeSi2(n)/a-Si(i)/c-Si(p)结构的太阳能电池进行模拟,依次讨论了本征层、发射层、界面态对电池性能的影响。结果表明:添加本征层电池性能提高,但随着本征层厚度的增加载流子收集率下降、串联电阻增大,造成电池光电转化效率下降;发射层厚度的增加使得载流子的收集率下降造成光电转化效率下降,同时发射层掺杂浓度增大虽然使得内建电场强度增大,但载流子的复合也会加大,最终使得电池性能保持稳定;界面态使得电池性能下降,为使电池获得较好性能,界面态密度应尽可能小于1011 cm–2·e V–1。通过优化,最终使得该结构的太阳能电池光电转化效率达到17.00%。     

紫外线辐照棉织物接枝壳聚糖改性及其性能分析

以柠檬酸（CA）为交联剂,以磷酸二氢钠为催化剂,对紫外线辐照棉织物接枝壳聚糖（CS）。研究了柠檬酸的质量浓度和水浴处理时间对壳聚糖接枝率的影响。得出最佳处理条件：15 g/L CS,100 g/L CA,20g/L磷酸二氢钠,70℃水浴下煮60 min,然后130℃干燥5 min,室温真空干燥24 h,壳聚糖接枝率为2.69%。对比了改性前后棉织物的染色性能、透湿透气性、折皱弹性和柔软性。结果表明：改性后棉织物的染料上染率为93.5%,较未处理的棉织物提高了20%,染色深度K/S值也提高了24%,而染色牢度没有改善;改性棉织物的透湿性能提高14%,但透气性能下降15%;改性棉织物的折皱弹性均有提高,其中急弹性回复角提高26.3%,缓弹性回复角提高14.7%;改性棉织物的柔软性略有下降。总体来说,接枝壳聚糖改性棉织物的整体性能有所提高。     

再生蚕丝丝素蛋白纳米颗粒的制备及抗茵性

采用一种高效简便新工艺,用特定的溶剂将家蚕丝素蛋白溶解,透析浓缩后用α-糜蛋白酶酶解,制备了蚕丝丝素蛋白纳米级颗粒,进行了4种不同溶剂溶解的筛选性实验.结果表明:采用LiBr/CH3OH/H2O溶剂溶解,透析浓缩后用α-糜蛋白酶酶解的整体工艺效果最优.对生成的纳米粒子尺寸用扫描电镜、场发射扫描电镜进行表征,观察到4种混合溶剂溶解得到的丝素蛋白肽颗粒大小在20～50 μm之间;再用α-糜蛋白酶酶解后,丝素蛋白肽颗粒的大小降解为80～300 nm.测定了丝蛋白肽粉末的抗菌性,其纳米级颗粒比微米级颗粒具有更优异的抗菌效果.     

金属材料长周期海水腐蚀规律研究

常用金属材料在我国的青岛、舟山、厦门和榆林4个海域的飞溅、潮差、全浸3个海洋区带中暴露1、4、8和16年的长周期腐蚀试验工作进行了研究，得到了长周期的海水腐蚀数据及其腐蚀规律．提出了一种海水腐蚀性的评价方法和一种综合评价材料耐蚀性的方法．