为了研究适用于制造车间的基于RSSI(Received Signal Strength Indication)测距的高精度定位算法,考虑到制造车间的复杂环境,本算法引入高斯滤波和均值滤波器减少定位误差,提高定位稳定性;提出了传输模型分区概念,对于处在不同的锚节点和同一锚节点的不同方位区间的节点,采用不同的无线信号传输模型计算盲节点与锚节点之间的距离;在所有的盲节点与锚节点之间的距离中选择最小的三个,采用几何三边测量法求取盲节点的坐标值。实验及数据分析可知,基于RSSI滤波、分区处理和距离优化后的定位算法,其实验样本的平均定位误差为0.8899m,较改进前提高了22%,同时定位精度较高且稳定性很好,经假设检验证明,本算法较原始的RSSI定位算法在定位效果上有了显著的提升。
提出了一种基于动态邻居表的分簇协议(clustering routing protocol based on dynamic neighbor table,CRBONT).它以满足特定条件的节点为中心,根据约定的广播半径,动态的建立广播半径内,所有节点的剩余能量组成的邻居表,并以此为依据选取簇头.仿真结果表明,CRBONT算法的簇头分布非常均衡,各个节点的能量消耗差距细微,第一个节点死亡时间明显延迟,能较好地延长网络的生存周期.
A cost-based selective maintenance decision-making method was presented.The purpose of this method was to find an optimal choice of maintenance actions to be performed on a selected group of machines for manufacturing systems.The arithmetic reduction of intensity model was introduced to describe the influence on machine failure intensity by different maintenance actions (preventive maintenance,minimal repair and overhaul).In the meantime,a resolution algorithm combining the greedy heuristic rules with genetic algorithm was provided.Finally,a case study of the maintenance decision-making problem of automobile workshop was given.Furthermore,the case study demonstrates the practicability of this method.
