基于随机服务的机器维修应用研究

为了合理安排机械设备的维修人员数量和避免因设备维修时间过长而带来的经济损失,将随机服务模型应用到机器维修上。介绍了随机服务模型的3个组成部分,在此基础上讨论M/M/1模型中如何选择维修速度以及M/M/S模型中如何确定维修工数目,最后给出一个维修实例。结果为管理者提供了准确合理的维修建议,对进一步的决策具有很大的指导作用。     

K18系列煤炭漏斗车故障及检修

概括K18DG、K18DF和K18AT等煤炭漏斗车的易发故障,分析故障原因,指出设计制造方面的不足,并提出了在检修中的改进措施及注意事项、车辆采购及管理措施。     

Product-cost modelling approach for the development of a decision support system for optimal roofing material selection

Selection of optimal roofing materials is very important but it is a complex and onerous task as varieties of materials are available for housing roof construction. In order to select suitable materials, an extensive range of criteria would need to be considered. This paper presents the framework and the development of a knowledge-based decision support system for material selection implemented in roofing material selection domain, called ‘Knowledge-based Decision Support system for roofing Material Selection and cost estimating’ (KDSMS). It was developed to facilitate the selection of optimal materials for different roof sub elements. The system consists of a database and knowledge base that is equipped with an inference engine. The former is used to store different types of roofing materials with assigned attribute values. The later is used to hold qualitative and quantitative knowledge which were collected from domain experts and other technical literatures such as building regulations, price guide book and product catalogues. The proposed system employs the TOPSIS (Technique of ranking Preferences by Similarity to the Ideal Solution) multiple criteria decision making method to solve materials selection and optimisation problem. This study utilised the available roofing materials in the UK housing market in developing the system reported. The main contribution of the developed system is that it provides a tool for the architects, quantity surveyors or self house builder to select optimal materials from a wide array of possibilities for different roof sub elements and also to estimate the conceptual cost for the roof element in the early stage of building design.     

SJ型虹吸式雨量计的日常维护及常见故障排除

文章阐述了SJ型虹吸式雨量计的结构和工作原理;介绍了日常使用中的维护和保养方法;对仪器的常见故障现象进行了详细地分析,并给出了相应的处理方法。     

航空地面液压设备PLC控制器抗干扰技术研究

针对航空地面液压设备PLC控制器极易受到恶劣电磁环境干扰的问题,提出了PLC控制器硬件抗干扰的技术措施,设计了PLC控制器软件抗干扰的运行程序。     

Satisfaction with health status among cyber patients: testing a mediation model of electronic coping support

There has been a growing interest among researchers about the Internet-based social support. However, not much is known about whether electronic support is associated with subjectively reported patient health outcomes. This study examines variation in satisfaction with physical health status among users of self-help groups for patients with cancer (N = 350). The analytical approach of the study differs from previous work in that satisfaction with physical health is modelled not as a predictor, but as an outcome variable. The study tested the hypothesis that perceived ability to cope with cancer mediates the association between electronic support and health satisfaction. Path analyses using ordinary least squares multiple regressions showed that there is an indirect association between electronic support and health satisfaction via perceived ability to cope with cancer. Electronic support increased perception of control over cancer, which in turn led to higher levels of satisfaction with health status. External health locus of control was associated with greater benefits derived from electronic support. This article concludes that the evaluation of physical health status includes not only clinical indicators but also subjective assessment of coping ability. Thus, the cyber social context in which health perceptions are developed has important medical implications for patient outcomes.     

A classification of tactical assembly line feeding problems

Trends like mass-customisation and the increasing number of models produced and parts used on a single assembly line promote interest in the field of assembly line feeding. The assembly line feeding problem (ALFP) deals with the assignment of parts to line feeding policies such as line stocking, boxed-supply, sequencing and kitting (stationary and travelling), and emerged as a research field two and a half decades ago. In order to structure the increasing effort in this field, we provide an extensive review of the literature and organise it from various perspectives. Furthermore, we propose a classification for the ALFP and classify existing literature. The goal of this classification is threefold. Firstly, it should help the reader to get an overview of the problem and most of its related aspects. Secondly, the classification reveals blind spots in academic research. Finally, it enables practitioners to match real-world problems with existing research results. In order to encourage researchers to close the existing gaps, we finalise this paper by pointing out the most important open research fields.     

基坑支护工程三轴搅拌桩施工方案

郑州市某高层商业办公楼基坑采用1 000 mm厚"两墙合一"地下连续墙,墙内外侧各做一排Ф850@600三轴搅拌桩作为槽壁加固。施工中严格按流程实施并采取多项技术措施,保证了基坑支护的质量。     

基于最优特征选择与支持向量机的钱塘江涌潮检测算法

以设计一种全新的背景模型算法为目标,依据图像像素特征之间的差异,使用高斯核函数获取像素特征的概率密度,统计不同区间的密度估计值,从特征池中选择适合的像素特征组成特征模板图,以输入视频流中对应位置的像素特征值作为输入量,使用支持向量机训练固定数目的像素特征值,对比分离出前景和背景。该方法应用于钱塘江涌潮检测的结果表明,F-measure值均在65%以上,鲁棒性较强;支持向量机方法选择径向核函数的识别率超过90%,运算速度较高。该方法能减少水面波动的干扰,具有较高的精度,可为河流动力特征描述提供重要工具。     

河道生态基流计算方法回顾与评估框架研究

回顾了国内外河道生态基流计算方法的发展历程并对比分析其异同,同时提出了国内河道生态基流的研究不足。开展了国内外河道生态基流计算方法的分类对比研究,讨论了不同类型计算方法的优缺点与适用条件,为不同计算方法的应用提供了依据。最后,构建了河道生态基流评估框架,分析了生态基流评估计算时的影响因素,提出了评估框架构建原则。通过构建生态基流决策支持系统提出了河道生态基流评估框架的分析流程。研究成果可为不同区域生态基流的确定提供技术支撑。