Three stage trade credit policy in a three-layer supply chain–a production-inventory model

The main purpose of this paper is to investigate the optimal replenishment lot size of supplier and optimal production rate of manufacturer under three levels of trade credit policy for supplier–manufacturer–retailer supply chain. The supplier provides a fixed credit period to settle the accounts to the manufacturer, while the manufacturer gives a fixed credit period to settle the account to the retailer and the retailer, in turn, also offers a credit period to each of its customers to settle the accounts. We assume that the supplier supplies the raw material to the manufacturer and sends back the defective raw materials to the outside supplier after completion of inspection at one lot with a sales price. The system always produces good items in the model. Also, we consider the idle times of supplier and manufacturer. Finally, numerical examples are provided to illustrate the behaviour and application of the model with graphical simulation.     

校园网网络计费相关的网络管理问题研究

网络流量计费是一种常见的网络管理手段。网络计费中经常遇到对流量统计结果的质疑、IP地址抢夺和账号被盗等三类问题。针对上述三类问题,通过网络管理的手段给出了分别的解决方案。     

Damage and deterioration mechanism and curing technique of concrete structure in main coal cleaning plants

Concrete structures in main coal cleaning plants have been rebuilt and reinforced in the coal mines of the Shanghai Da-tun Energy Sources Co. Ltd., the first colliery of the Pingdingshan Coal Co. Ltd. and the Sanhejian mine of the Xuzhou Mining Group Co. Ltd. In these projects, the operating environment and reliability of concrete structures in the main plants of the three companies were investigated and the safety of the structures inspected. Qualitative and quantitative analyses were made on the spe-cial natural, technological and mechanical environments around the structures. On the basis of these analyses, we discuss the long-term, combined actions of the harsh natural (corrosive gases, liquids and solids) and mechanical environments on concrete structures and further investigated the damage and deteriorating mechanisms and curing techniques of concrete structures in the main coal cleaning plants. Our study can provide a theoretical basis for ensuring the reliability of concrete structures in main coal cleaning plants.     

朴素贝叶斯与全贝叶斯在DFI的应用比较研究

P2P应用软件检测技术主要是深度包检测法和深度流量检测法.深度包检测法不能检测出加密的和未知的对等网络流应用,深度流量检测方法可以克服深度包检测法这个缺点.将模糊识别领域里比较成熟的贝叶斯分类技术应用到对等网络深度流检测中.结合实际项目,对贝叶斯的两个分类器-朴素贝叶斯和全贝叶斯的算法、训练结果、运行结果进行研究,实验研究表明朴素贝叶斯和全贝叶斯分类器能够快速准确地找到P2P流应用,朴素贝叶斯分类器准确度占据优势,全贝叶斯运行时间占据优势.     

基于X射线的钢丝绳芯无损探伤系统研究

设计了一种基于X射线的钢丝绳芯无损探伤系统。该系统利用X射线的良好穿透性检测钢丝绳芯输送带中的钢丝绳缺陷,采用光纤将现场采集的图像信息传输到远程上位机中进行分析处理,实现了钢丝绳芯缺陷图像的在线智能识别和分析等功能。原理样机测试结果表明,该系统能够检测出切断、凿穿、接头抽动、撕裂等钢丝绳缺陷,在保证X射线安全工作的前提下,提高了检测效率和准确性。     

机械电器产品检验抽样方法探讨

根据机电产品生产特点,对稳定生产状态下的生产条件进行细分,提出不同生产条件下的生产质量验收抽样方法。     

基于自编码和知识蒸馏的表面缺陷检测方法

针对传统的表面缺陷检测方法只能对具有高对比度或低噪声的明显缺陷轮廓进行检测的问题,提出了一种基于自编码和知识蒸馏的表面缺陷检测方法来准确定位和分类从实际工业环境捕获的输入图像中出现的缺陷。首先,设计了一种级联自动编码器（CAE）架构用于分割和定位缺陷,其目的是将输入的原始图像转换为基于CAE的预测蒙版;其次,利用阈值模块对预测结果进行二值化以获得准确的缺陷轮廓;然后,把缺陷区域检测器提取并裁剪出来的缺陷区域视为下一个模块的输入;最后,将CAE分割结果的缺陷区域通过知识蒸馏进行类别分类。实验结果表明,与其他几种表面缺陷检测方法相比,所提出的方法综合性能最好,其缺陷检测平均准确率为97.00%。该方法能够有效地对较小的、边缘不清晰的缺陷进行分割,满足对物品表面缺陷实时分割检测的工程要求。     

Autoencoder-based anomaly detection for surface defect inspection

In this paper, the unsupervised autoencoder learning for automated defect detection in manufacturing is evaluated, where only the defect-free samples are required for the model training. The loss function of a Convolutional Autoencoder (CAE) model only aims at minimizing the reconstruction errors, and makes the representative features widely spread. The proposed CAE in this study incorporates a regularization that improves the feature distribution of defect-free samples within a tight range. It makes the representative feature vectors of all training samples as close as possible to the mean feature vector so that a defect sample in the evaluation stage can generate a distinct distance from the trained center of defect-free samples. The proposed CAE model with regularizations has been tested on a variety of material surfaces, including textural and patterned surfaces in images. The experimental results reveal that the proposed CAE with regularizations significantly outperforms the conventional CAE for defect detection applications in the industry.     

面向动用计划的车辆装备备件预测研究

针对动用计划下的车辆装备备件的消耗特点,研究了车辆装备维修备件消耗量和库存控制两个预测优化问题。考虑动用计划期内车辆装备的预防性维修和修复性维修,实现定时定程维修和自然随机故障维修下装备维修备件的消耗量的预测。在此基础上,根据备件库存检查方式的特点,建立基于定期检查策略的联合补货库存控制模型,根据模型的结构特点确定决策变量界限,并利用多类种群位置更新方式改进了果蝇优化算法。仿真结果表明,改进的果蝇优化算法具有良好的求解效率,本文所提出的优化方法可为车辆维修保障资源优化提供决策依据。     

基于BIM的钢筋骨架语义设计点云自动生成算法

当前预制构配件钢筋骨架质量检查主要依靠人工,存在效率低、容易出错的问题。建筑信息模 型(BIM)、三维重建等技术为改进预制构配件钢筋骨架质量检查方法提供可能。运用这些技术时,有必要由钢 筋骨架 BIM 模型生成可区分每根钢筋的点云。为此,提出了语义设计点云的概念,并构建了基于 BIM 的钢筋 骨架语义设计点云自动生成算法。该算法首先从钢筋骨架 BIM 模型中提取每根钢筋并分别存储于不同的文件, 然后对每根钢筋所在文件进行格式转换,接着生成每根钢筋的语义设计点云,最后基于每根钢筋的语义设计点 云生成钢筋骨架语义设计点云。分别用简单钢筋骨架和复杂钢筋骨架对基于 BIM 的钢筋骨架语义设计点云自 动生成算法进行实验验证,结果表明,该算法能够自动并快速地生成准确的钢筋骨架语义设计点云。