Design of delayed reconfigurable manufacturing system based on part family grouping and machine selection

To improve the convertibility of reconfigurable manufacturing system (RMS), the concept of delayed reconfigurable manufacturing system (D-RMS) was proposed. RMS and D-RMS are both constructed around part family. However, D-RMS may suffer from ultra-long system problem with unacceptable idle machines using generic RMS part families. Besides, considering the complex basic system structure of D-RMS, machine selection of D-RMS should be addressed, including dedicated machine, flexible machine, and reconfigurable machine. Therefore, a system design method for D-RMS based on part family grouping and machine selection is proposed. Firstly, a part family grouping method is proposed for D-RMS that groups the parts with more former common operations into the same part family. The concept of longest relative position common operation subsequence (LPCS) is proposed. The similarity coefficient among the parts is calculated based on LPCS. The reciprocal value of the operation position of LPCS is adopted as the characteristic value. The average linkage clustering (ALC) algorithm is used to cluster the parts. Secondly, a machine selection method is proposed to complete the system design of D-RMS, including machine selection rules and the dividing point decision model. Finally, a case study is given to implement and verify the proposed system design method for D-RMS. The results show that the proposed system design method is effective, which can group parts with more former common operations into the same part family and select appropriate machine types.     

Color Grouping in Space and Time: Evidence From Negative Color-Based Carryover Effects in Preview Search.

Five experiments addressed the role of color grouping in preview search (D. G. Watson & G. W. Humphreys, 1997). Experiment 1 used opposite color ratios of distractors in preview and second search displays, creating equal numbers of distractors in each color group in the final display. There was selective slowing for new targets carrying the majority color of the old items. This effect held when there was no bias in the preview and only the second search set had an uneven color ratio (Experiment 2). In Experiment 3, participants had foreknowledge of the target color, and effects were shown over and above those due to color biases. Experiment 4 demonstrated negative color carryover even when previews changed color. Experiment 5 showed reduced color carryover effects when previews were presented more briefly. Collectively, the results provide evidence for inhibitory carryover effects in preview search based on feature grouping. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perceptual primitives from an extended 4D Hough transform

Directional features extracted from Gabor wavelets responses were used to train a structure of self-organising maps, thus classifying each pixel in the image within a neuron-map. Resulting directional primitives were grouped into perceptual primitives introducing an extended 4D Hough transform to group pixels with similar directional features. These can then be used as perceptual primitives to detect salient structures. The proposed method has independently fixed parameters that do not need to be tuned for different kind or quality of images. We present results in application to noisy FLIR images and show that line primitives for complex structures, such as bridges, or simple structures, such as runways, can be found by this approach. We compare and demonstrate the quality of our results with those obtained through a parameter-dependent traditional Canny edge detector and Hough line finding process.     

一种新的知觉分割模型*

根据知觉的最新理论研究和实验结果,提出一种新的知觉模型,并用于考查计算机视觉中的分割问题.分割问题实质上是知觉表达问题,现在分割的困难性可能是知觉上局部到整体的还原论假设造成的;分割可能不是一次完成的,而是经过整体到局部的过程才最终完成.新的知觉模型将对建立更好的分割模型提供理论基础.     

红细胞瞬间磁化试剂的制备与应用

目的研制用于ABO、RHD血型检测试剂的红细胞瞬间磁化试剂。方法采用共沉淀法制备磁性粒子,并检测其主要成分及粒径大小,用此磁性粒子制备红细胞瞬间磁化试剂,并分别进行各项检测。结果磁性粒子的主要成分为四氧化三铁,粒径100nm左右。该试剂的外观及特异性均合格,磁响应时间不超过30s,重复性较好,敏感性为98.20%,与试管法检测结果比较,差异无显著意义。结论红细胞瞬间磁化试剂可用于红细胞系统的血型检测。     

基于WIFI+GPRS的无线传感器网络监控系统

传感器网络是一个将传感器技术、嵌入式系统、通信网络技术相结合的网络,实现数据采集、无线定位、远程监控、设备管理等功能,结合ZigBee、WIFI、GPRS等无线网络的优点,构建一个异构无线传感器网络,实现无线网络和移动通讯刚络的远程数据采集、定位与控制、异常事件报警,系统通过无线传感器终端节点进行数据采集,利用具有接收、转发数据助能的无线网络接收,实现异构网络终端设备间的数据交互与共享,达到无线定位,短信报警、上位机软件监控的目的．     

融合多种策略的改进粒子群算法

为有效解决粒子群优化算法(Particle Swarm Optimization, PSO)容易陷入局部极值及进化后期收敛速度慢、精度低等缺点, 提出了一种融合多种策略的改进粒子群算法(Improved Particle Swarm Optimization, IPSO). 该算法包括以下4点改进:(1)采取分组控制策略, 按适应度值将种群分为优解组和劣解组, 优解组进行遗传交叉操作, 劣解组进行变异操作; (2)精英策略用来更新种群, 根据适应度值从经过交叉和变异操作后的种群及初始种群中选出前一半粒子作为新种群; (3)改进粒子学习模式, 充分利用种群信息, 以优良种群的均值代替个体最优位置;(4)引入概率控制来控制算法进入交叉和变异操作的概率. 测试函数的仿真结果表明, 与标准PSO及其改进算法相比, IPSO算法能有效兼顾全局探索和局部挖掘能力, 具有收敛速度快、求解精度高、避开局部最优解的优点.     

考虑用户偏好和平台收益的共享泊位分配模型

与机动车数量激增类似,泊位短缺也是导致城市交通拥堵主要问题之一,在不增加车位的情况下提高泊车位利用率也是解决交通拥堵的一种方法。针对城市“泊车难”和部分泊车场利用率较低的问题,考虑了用户的偏好特征,研究了一种具有用户偏好的泊车位共享策略。考虑存在三种不同的泊车方式,在中央商务区（CBD）等待泊车、共享私人泊位、共享公共泊位,运用累积前景理论分析用户的泊车成本,发现用户在不同情形下的选择存在差异。平台通过对关键路径法修改,采用了偏好分组法进行分配。算例对偏好分组的结果与采用关键路径法的分配结果进行了比较,结果表明,基于偏好分组法的分配满足了更多的用户需求,平台收益更高,为管理者提供决策参考。     

基于分组策略的补货配送问题优化模型

针对已存在的供应链环境下较少考虑补货配送问题中的分组配送策略,结合大量零售商对单一产品需求量不同等特点,引入分组的决策变量.根据配送中心补货周期与配送次数的函数关系,以最小化三级供应链系统的平均总成本为目标,构建了带有配送中心能力约束的补货配送优化模型.根据优化模型的特点,利用改进的遗传算法求解模型,并进行了数据仿真试验.结果表明,该优化模型能为配送中心提供一种有效的分组配送方案,选择的优化算法更稳定快捷,能为企业提供有益的管理启迪.     

一种改进的人工蜂群算法

从经典人工蜂群算法机制出发,针对原始算法在初始种群构造、子种群分组、步长更新和种群淘汰方面的不足进行了改进.新算法运用均匀设计理论构造初始种群,提出了一种种群交叉的Z型分组方法,设计了一种对数函数自适应步长代替原来的随机步长,引入了小生境技术及时淘汰陷入局部最优的个体.实验结果表明,改进后的算法有效地解决了人工蜂群算法早熟收敛、搜索速度较慢等问题,并提高了解的精度.