Field reliability modeling based on two-dimensional warranty data with censoring times

ABSTRACT

Warranty data can be used for estimating product reliability, identifying causes of failure and designing warranty policy. Based on two-dimensional warranty data, we utilize an accelerated failure time model to investigate the effect of usage rate on product degradation. The stochastic expectation-maximization algorithm is proposed to estimate parameters of the reliability model considering both censored data and field data. Extensive simulation studies are used to validate the proposed method and to compare it with the maximum likelihood method. The utilities of the results have been demonstrated through real warranty data collected from an automobile manufacturer in China.     

Visible light communications heterogeneous network (VLC-HetNet): new model and protocols for mobile scenario

Wireless Networks - In order to resolve the crowded radio spectrum of wireless communication systems, visible light communications (VLC), which uses a vast unregulated and free light spectrum, has...     

A study of degradation phenomenon of Ni–Pt/CeO2 catalyst towards hydrogen generation from hydrous hydrazine

Catalytic decomposition of hydrous hydrazine (N₂H₄·H₂O) has received considerable attention as a promising chemical hydrogen storage system. But the currently available N₂H₄·H₂O decomposition catalysts always showed poor durability. In the present paper, we report an experimental study of the performance degradation of Ni–Pt/CeO₂ catalyst using TPD-MS, FTIR, HRTEM techniques. Our study on the post-used Ni–Pt/CeO₂ catalyst found that a predominant N₂ species and various reaction intermediates over-strongly bound on the catalyst surface. Furthermore, the amount of the bound N₂ species at Ni sites is approximately linearly correlated with the activity decay degree. These results provide a straightforward explanation of the performance degradation phenomenon and highlight the critical role of adsorbate/catalyst interaction in determination of the catalytic performance.     

Joint optimisation of tracking capability and price in a supply chain with endogenous pricing

Tracking systems have been widely used to resolve the issues of product recall and food safety. Thus far, few researches have been done on designing the tracking capability from the perspective of supply chain. In this paper, using the traceable unit size at the manufacturer level to measure the tracking capability, we propose a non-convex non-linear programming to jointly optimise the tracking capability and price considering the tracking cost and recall cost in a supply chain with endogenous pricing. Results show that, in both centralised and decentralised supply chains, there is a unique tracking capability and retailing/wholesale price with closed-form solutions to optimise the supply chain profit. When the cost ratio (unit tracking cost/unit recall cost) is sufficiently large and small, the optimal tracking strategy is barcode tracking and unit tracking, respectively, and otherwise, the optimal tracking strategy is batch tracking with an economic traceable unit size which depends on the cost ratio, quality inspection threshold, supply defection rate and the supplier’s tracking capability. Furthermore, in the context of large and small cost ratio, we find that improving tracking capability will enlarge and mitigate the effect of double marginalisation, respectively. In particular, we find that the strict tracking regulation policy is more robust than the subsidy policy to improve the supply chain tracking capability.     

基于C++的NXOpen和Journamation二次开发技术的研究和应用

以NX软件为平台,详细阐述了NXOpen开放式架构的特点和NXOpen客户化开发功能,归纳总结了基于C++的NXOpen和Journamation二次开发技术的流程和工作原理。以NX软件建模模块为例进行Journamation开发,实现了客户化功能的快速开发。     

福建某全覆式离子型稀土矿床注收液系统工程优化的研究

离子型稀土矿床根据矿层底板基岩出露方式分为两大类,分别是裸脚式和全覆式。为提高全覆式矿床的综合回收率,需从注收液工程布置两大方面进行施工优化设计,注液工程优化主要从减少矿体的注液盲区及注液方案考虑。收液巷道工程优化主要从巷道走向、巷道组合形式、巷道工程间距、收液巷道坡度角控制、巷道铺底等方面进行,本文结合全覆式稀土矿床的地质条件,进行注收液工程的优化.通过生产实践,母液回收率达到了86.65%,综合回收率达到了79.15%。对全覆式离子型稀土矿床的开采提供了一定的借鉴意义。     

现代控制理论在过程工业中的应用和发展

介绍了现代控制理论的发展、特点和分类。分析了现在较为流行的预测控制系统及在过程控制领域中的应用和发展趋势。介绍了智能控制研究的几个理论分支,从工业过程控制方面分析了当前智能控制的应用领域,指出了其中的研究重点和未来的研究方向。     

基于复杂网络理论的电力系统脆弱性分析

针对大区域电网发展及其安全稳定问题,基于复杂网络理论研究了电力系统大面积停电事故与电网连锁故障的内在机理。从电网拓扑模型和脆弱性评估指标的角度出发,分析、类比了各评估方法,指出当前应用复杂网络理论研究电力系统脆弱性方法尚存不足,电网与其他复杂网络的本质区别是研究的瓶颈问题。通过改进评估模型反映电网本质特性及其运行状态,指出了提高评估精度是下一步研究的重点。     

集成电路测试系统通用测试软件的研究与设计

介绍了一种集成电路测试系统通用测试软件的设计方法和软件组成。利用多层次、模块化的软件结构设计方法,令描述被测器件的参数和测试程序互相分离,并以图形化的方式利用测试模块构建测试序列文件,使得该集成电路测试软件具备良好的通用性,可维护性和可扩充性。     

关于高校教学档案计算机管理的思考

作为高校档案之一的教学档案工作,在整个教学管理和实践中发挥着重要的作用.随着高校科技教育网的兴起和普及,必将带动档案的全面信息化.