基于压力检测的汽车空调故障分析与排除

汽车空调常在复杂条件下作业,使得空调系统频繁发生故障。为了有效确保空调系统稳定运行,发挥自身的最大优势,不仅应做好正确使用、日常维护与常规保养工作,还要加大故障隐患排除和维修处理工作的力度,以此实现汽车空调系统的正常运行。文章对压力检测下的汽车空调故障分析与排除策略进行了分析。     

基于FMECA方法的无人机航电系统维修决策

本文首先介绍了无人机航电系统的功能结构,然后,分析了对无人机航电系统进行FMECA分析的方法;最后,以舵机实例分析结果为依据,研究分析了航电系统的维修工作内容制定、预防性维修间隔期确定和预防性维修工作组合等FEMCA关键技术。     

汽车空气流量传感器的检测与维护研究

文章针对汽车空气流量传感器本身结构较复杂,故障发生频率较高,检测相对复杂的特点,校企专业创新团队成员结合汽车维修工作实际,开展了检测与维护的技术研究。文章阐述了较为细化的汽车空气流量传感器的检测方法和维护方法。     

单片机在电缆设备故障检测中的应用

单片机在电缆充气设备检测系统的功能、设计原理、应用及其发展前景。通过单片机技术及时发现电缆充气设备的故障情况，减少了误差，使维修工作取得主动，保证了通信畅通，使故障检测达到信息化。     

关于机床液压系统噪声分析与振动防治

机床的液压系统机构复杂,因此导致故障产生的原因也非常多,在对机床液压系统进行维修时,通常会同时维修多个故障,这些故障可能相互关联,因此需要考虑和处理的问题也非常多,所以需要首先对当前情况进行分析,制定出维修工作的优先级,以提高维修工作的工作效率,在维修后要及时总结经验,做好记录,为以后的维修工作打下基础。     

机载综合导航系统方位信号模拟器的设计

机载综合导航系统方位信号模拟器可用于机载综合导航系统处于全向测向和定向测向两种工作方式下,方位系统工作情况的检测,是对综合导航系统测向性能测试和故障维修的必备仪器。文章在简要分析综合导航系统的功能组成和信号特性的基础上,阐述了综合导航系统方位信号模拟器的设计思路和工作原理。     

基于经济的复杂系统预防维修模型研究

文章针对存在经济性的复杂系统,从经济的角度,考虑实际复杂系统设备维修中的不完备维修,基于时间延迟和最大可用度要求,提出了一种以系统预防维修费用率最小化为目标的优化模型。并对实例运用计算机对模型的求解进行了案例分析。     

汽车检测系统预维修策略分析

随着汽车保有量的逐年增加和汽车制造业技术的进步,对汽车检测与诊断也提出了更高要求。采用预防性维修成为汽车检测系统设备管理的一种有效的方法,即采用预维修,在真实故障出现之前,综合运用各种技术和管理策略,使汽车检测系统处于正常工作状态,完成生产作业计划所规定的各项检测任务。     

论汽车电控发动机的故障及诊断

现代汽车广泛采用电子控制技术,其电气设备、系统结构日趋复杂和精密。对汽车各系统和用电设备的控制基本实现了功能组合化、控制电子化和连接标准化,使汽车的性能更加完善。同时对汽车的故障诊断与维修有了更高层次的要求。因此,在对电子控制发动机的故障诊断与维修方面,不能再延续传统的经验检查方法进行故障判断。而应在一定经验积累上,借助先进的检测设备,运用先进的检查方法,结合故障发生原因、现象和检测结果,充分利用技术维修资料,认真思考和分析,判断故障范围,有针对性的解决故障问题。为此,现试就汽车电控发动机无法起动的故障进行分析,指出了故障诊断与排除的方法。     

浅议汽车发动机怠速不稳表现方式及解决对策

汽车发动机怠速不稳故障的诊断更加复杂,但是利用先进的专业检测仪器和汽车维修人员长期的经验积累,此类故障的准确诊断和排除仍然是能够做到的.作为汽车维修人员,应该在日常工作中注意积累经验,并且总结维修知识和规律,不断提高自己的维修技能并为他人提供一些有用的借鉴.     

基于多级库存的电网运维物资安全库存优化配置研究

针对电力公司运维物资多级库存体系与安全库存配置现状,结合安全库存聚集效应,文章提出了周转库安全库存差异聚集策略。在综合考虑库存持有成本与普通、紧急配送成本的基础上,构建了安全库存优化配置模型。通过两类电网运维物资实际数据的分析,验证了差异聚集策略下成本低于全部聚集以及全部分散策略,可以为电力公司物资集约化、差异化、精益化管理以及仓库定额配置提供依据。     

基于功能区间的价值工程理论在工程中的应用

工程是一个相对复杂的系统,要对其功能进行精准的定位比较难,因为每个工程成本所对应的是一个功能区间,而非功能点。本文结合概率学的相关知识,提出了基于功能区间的价值工程理论模型,并认为工程建设的立足点应该是在可靠性上,而非追求"最低成本"或"最大价值"。     

考虑役龄阈值的最佳缓冲区库存维修策略研究

预防性维护PM对于生产系统有重要的作用。由于设备维护时会造成生产停滞,影响企业的经济效益,所以在生产线上下游设备之间建立库存缓冲区,保证生产的持续进行。考虑引入设备役龄阈值,构建费用模型和维护策略模型。以设备役龄阈值和缓冲区库存量为自变量,以最小化周期内总费用为目标,获得最佳的设备役龄阈值和缓冲区库存量。最后运用Matlab仿真软件进行了算例分析,验证了模型的有效性。     

Collaborative conceptualisation: towards a conceptual foundation of interoperable electronic product catalogue system design

The maintenance of semantic consistency between numerous heterogeneous electronic product catalogues (EPC) that are distributed, autonomous, interdependent and emergent on the Internet is an unsolved issue for the existing heterogeneous EPC integration approaches. This article attempts to solve this issue by conceptually designing an interoperable EPC (IEPC) system through a proposed novel collaborative conceptualisation approach. This approach introduces collaboration into the heterogeneous EPC integration. It implies much potential for future e-marketplace research. It theoretically answers why real-world EPCs are so complex, how these complex EPCs can be explained and articulated in a product map theory for heterogeneous EPC integration, how a semantic consistency maintenance model can be created to satisfy the three heterogeneous EPC integration conditions and implemented by adopting a collaborative integration strategy on a collaborative concept exchange model, and how this collaborative integration strategy can be realised on a collaboration mechanism. This approach has been validated through a theoretical justification and its applicability has been demonstrated in two prototypical e-business applications.     

浅析软件维护

软件维护是软件生命周期的最后一个阶段,并且软件维护的成本大约占总开发成本70%以上,软件维护的巨大成本使得软件工程研究人员不得不对它更加重视。本文以软件工程原理为基础,分析了软件维护的类型和影响因素,提出了一些软件维护策略和未来的努力目标。     

A particle swarm model for estimating reliability and scheduling system maintenance

Modifying data and information system components may introduce new errors and deteriorate the reliability of the system. Reliability can be efficiently regained with reliability centred maintenance, which requires reliability estimation for maintenance scheduling. A variant of the particle swarm model is used to estimate reliability of systems implemented according to the model view controller paradigm. Simulations based on data collected from an online system of a large financial institute are used to compare three component-level maintenance policies. Results show that appropriately scheduled component-level maintenance greatly reduces the cost of upholding an acceptable level of reliability by reducing the need in system-wide maintenance.     

Postponement strategy for international transfer of products in a global supply chain: A system dynamics examination

This paper contributes to research on “postponement” strategy in the context of a global production–distribution system of an automobile manufacturer. It proposes a model that integrates multiple considerations germane to global supply chains. Postponement is important in this context because it is necessary to consider international transfers and tariffs, and it is important to appropriately account for the impact of postponement on total costs. Consideration of several key variables such as shipping point, customs tariff, and cost differences between countries is essential to derive full benefits from postponement strategy in global supply chains. International transfer of goods among countries in global automobile industry is complex and dynamic because of the multitude of factors that must be considered. The paper develops insights regarding postponement strategy in global supply chains via a system dynamics simulation model. The model draws on the experiences of a Korean automobile manufacturer with operations in developing and developed countries.     

Optimal maintenance center inventories for fault-tolerant repairable systems

In many military and commercial contexts, complex equipment which is expected to perform very reliably is often designed to be fault-tolerant, that is, able to function although some of the parts have failed. A popular fault-tolerant design is the m-out-of-n system, where there are n identical parts, at least m of which must be functional for machine operation. Complex equipment of this type often undergoes scheduled maintenance overhauls at regular intervals during which all failed components are replaced. Failure to have replacements on hand for failed parts requires emergency measures at premium cost. When repairable parts are highly reliable and expensive, both holding and shortage costs are high. A reasonable objective is to choose initial spares inventory to minimize the sum of holding costs and expected shortage costs.We first develop a model to determine the optimal repairable parts inventory for a maintenance center servicing machines containing a single m-out-of-n system. The model is then extended to handle a related problem, finding optimal maintenance center inventories for machines containing several m-out-of-n systems of different parts, minimizing total expected costs subject to a constraint on total inventory investment.We assume that there is a fleet of machines, which experience identical workloads. There is a cycle time of T days between overhauls for an individual machine. A machine arrives at the maintenance center for overhaul each day. At the overhaul, all failed parts are removed and sent to a repair shop, from which they eventually return to the maintenance center to be used again as spares. The total number of spares undergoing repair and on hand is a constant. There are no backorders; if the number on-hand spares is insufficient to meet demand at an overhaul, a shortage penalty is assessed which depends on the number and type of spares required.While computing holding costs is straightforward, computing expected shortage costs is more complex. Expected shortage costs are dependent upon several factors, including component failure rates, the values of m and n, part repair rates, and the initial number of spares on hand. We assume that the system of interest is well specified, so that the parameters of the model are known except for the number of initial spares of each type, which are the decision variables. We model the on-hand inventory of each type of part as a Markov chain with the number of spares on hand at the end of each day as the states, under the assumptions that failure rates are constant and repair times follow independent exponential distributions. We then calculate the steady-state probabilities of stockout of various numbers of spares, as a function of the initial spares inventory. The expected shortage costs for a given type of spare may then be calculated by finding the product of the penalty cost for lacking p spares and the probability of lacking p spares and summing over all possible p values.Solutions to the problem of finding optimal initial inventory level for a machine containing a single m-out-of-n system may be found easily by enumeration. Solutions to the constrained problem where the machine contains several independent m-out-of-n systems, may be found by dynamic programming. Sensitivity analysis of costs to changes in the inventory investment constraint is clear, and computational effort is reasonable. A simple example is included to illustrate the solution method for both problems.     

武器系统全寿命周期费用的控制和管理的研究

现代武器装备技术复杂、研制周期长、风险大、费用昂贵,采办具有很强的不确定性和不可预见性。为提高武器装备的效费比和国防资源的利用效率,保证论证、研制、生产、使用、维护等环节衔接顺畅,最可行的方法是实行武器装备的全系统全寿命管理。文章针对武器系统全寿命周期费用的控制和管理工作进行了研究。     

公路养护工程财务管理问题的探讨

公路施工规模大、周期性长以及施工复杂,施工后期的养护工作是保障其质量的重要手段。近几年,我国针对公路养护工作推出了养护会计制度及燃税改革制度,财务管理工作在公路养护过程中的作用越来越明显,良好的财务管理不仅能提高施工质量,还能在很大程度上节约建设资金。在实际管理过程中,公路养护财务管理仍面临诸多问题,公路施工单位发展的当务之急是如何解决这些问题。