Cost effects of mergers and deregulation in the U.S. Rail industry

We attempt to disentangle the effects of deregulation on rail costs from those directly attributable to mergers and acquisitions, employing a translog variable cost function, based on an unbalanced panel data set of annual observations for major U.S. Class I railroads from 1974 to 1986. We find that both deregulation and mergers contributed significantly to cost savings. However, of the accumulated cost savings achieved by the six major firms involved in mergers postderegulation, we estimate that by 1986 about 91% of the reduction in accumulated costs is due to deregulation, and about 9% is directly due to mergers and acquisitions (which in turn were facilitated by regulatory reforms).     

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.     

Deregulation, Mergers, and Cost Savingsin Class I U.S. Railroads, 1974-1986

In this paper we attempt to disentangle the effects of deregulation on rail costs from those directly attributable to mergers. We estimate that cost reductions obtained from mergers ranged from a high of 33% for the Burlington Northern to a low of a 3% cost increase for the CSX. However, firms not engaged in significant merger activities experienced similar cost differentials indicating that consolidation was not a prerequisite for cost savings. We conclude that although mergers did confer some benefits on the participating firms, they were not a prerequisite for railroads being able to achieve substantial cost savings.     

热电厂采暖热网加热器运行容易出现的问题及综合治理办法

论文全面分析了热网加热器在检修、运行维护、保养、选型等容易出现的问题,并提出解决方案和建议,以保证加热器的长期安全高效运行。     

Regulation and cost efficiency in the European railways industry

The objective of this article is to analyze European railways’ incentives to improve efficiency in the recent liberalization context. We build and estimate a structural model accounting for regulatory pressures faced by the firms. Our model includes demand equations, capacity constraints and a cost function, in which are specified an exogenous technical efficiency component and an endogenous cost reducing effort parameter. We find a significant positive effect of implementing the reforms on cost reducing activities, and a smaller cost of effort for firms choosing a more advanced separation of infrastructure from operation activities.     

全固态电视发射机电源和功放的故障检修

主要介绍全固态电视发射机功放模块常见故障的检修,电源常见故障的检修,建立功放维修平台的具体操作步骤,文章引进实物操作图,以增强实用性和指导性。     

基于35kV以下变电检修的研究

随着科技的不断发展,推动了我国电网事业的不断发展。为了保证电网的稳定运行,开展变电检修工作不可或缺。我国变电检修工作虽然起步较晚,但经过最近十几年的发展也取得了一定成就。近年来,大量高科技电气设备不断应用于我国的电网中,为我国的变电检修工作带了巨大挑战,如何提高变电检修,保证我国的电网的稳定运行,是现目前很多供电企业越来越关注的问题。本文首先对变电检修进行了概述,探讨我国35kV以下变电检修的日常检修工作和年度检修工作,提出一些提高变电检修的建议,以期为我国的变电检修工作提供一些参考。     

康明斯发动机操作及维护保养要点

康明斯发动机采用国际上流行的标准集成化模块式设计,结构简单紧凑,配件通用化程度高。采用增压、增压中冷以及空气对空气中冷措施,仅改变与发动机动力有直接关系的零部件。可获得不同功率,不同用途的发机系列。为了使康明斯发动机更好使用,也使维修人员尽快地掌握维修技术,现将康明斯发动机操作及维护保养要点作简要的介绍。     

沥青路面双层同时摊铺的必要性及施工工艺分析

沥青路面由多个结构层组成，传统的施工工艺易造成层间粘结力下降甚至其它病害，同时沥青路面养护及大修后，也极易产生沥青层间粘结力不足等缺限。文中就此问题进行探讨，为新建沥青路面或改建沥青路面提供借鉴。     

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.     

轮对智能立体存储库在昆明北车辆段中的应用

随着我国铁道事业的快速发展,铁道车辆的保有量持续增长,车辆的检修需求量也随之增长。轮对检修是在轨道车辆转向架检修中的一个关键环节,是决定动车安全可靠舒适运行的核心环节之一。本文介绍了智能立体存储库首次应用于昆明北车辆段,可以满足各型货车轮轴(包括RD2.RE2A/RE2/RE2B型轮轴)的智能仓储、选配[1]支出要求。     

汽车发动机冷却系统的故障诊断与维修

要使发动机工作可靠、耐久,冷却系统应使发动机在最适宜的温度范围内工作。保证发动机工作在适宜温度范围内,则要做好很好的故障检测。根据发动机冷却系统出现过热运转和过冷运转可能出现的问题进行分析诊断,同时就出现的故障如何进行维修与保养进行了论述。     

化工仪表常见故障与检修方法研究

化工仪表是化工设备运行的有效监视者,化工仪表显示的各种信息对于保证仪器设备的正常运行以及设备维修具有重要的作用,随着化工设备自动化的发展,化工仪表的自动化程度也在不断增强,但是化工仪表复杂程度也日益加深,其也就存在一定的故障。本文通过对常见化工仪表的种类进行阐述,分析化工仪表常见的几种故障,最后提出检修这些故障的具体方法。     

关于固原东饮工程建设及运行管理若干问题的探讨

文中就固原东饮水工程由于地方配套资金落实不到位,工程迟迟不能完建和竣工验收,以及工程年运行管理及维修费用高,水费收缴难度大等问题,分别进行论述和分析,并针对性提出对策建议,以期推动公益性水利工程健康稳定发展。     

Profit, productivity and distribution: Differences across organizational forms - The case of Spanish banks

We examine variations in financial and economic performance as a function of organizational form, and, over time. The forms we consider include Spanish commercial banks, savings banks, and financial cooperatives. We decompose multilateral variation in operating profit, our measure of financial performance, into price and quantity effects. We then decompose the latter into a margin effect and productivity change. Our measure of economic performance, productivity variation, is subsequently disaggregated into technical, cost efficiency, and scale. We find that deregulation and liberalization have acted to narrow performance gaps among organizational forms; this, despite less-than compelling evidence that increased competition has contributed to this convergence. For the Spanish banking system as a whole, the margin effect appears to deliver twice as much financial benefit as do improvements in productivity. Importantly, this finding does not vary across organizational form. Such regularity has an important implication: Incentives for growth are apparently provided by a positive margin rather than by the more elusive benefits of economies of scale and improved cost efficiency.     

Capital maintenance and depreciation over the business cycle

This paper develops and estimates a stochastic general equilibrium model with capital maintenance, which affects endogenously the depreciation rate of capital. The estimate of maintenance series is found to track survey-based measures for Canada quite closely and to generate the procyclical pattern of maintenance observed in the data. We use our model estimates to infer the time profile of equipment capital depreciation in Canadian and US manufacturing. The depreciation rate is estimated to be volatile and highly procyclical in both countries.     

Risk premia and seasonality in commodity futures

We develop and estimate a multifactor affine model of commodity futures that allows for stochastic seasonality. We document the existence of stochastic seasonal fluctuations in commodity futures and that properly accounting for the cost‐of‐carry curve requires at least three factors. We estimate the model using data on heating oil futures and analyze the contribution of the factors to risk premia. Correctly specifying seasonality as stochastic is important to avoid erroneously assigning those fluctuations to other risk factors. We also estimate a nonlinear version of the model that imposes the zero lower bound on interest rates and find similar results.     

Optimale revisietijd

Optimum period of overhaul, a case-study
A general formula is given, when to proceed to an overhaul in such a way that the costs of wear and those of overhaul together will be a minimum (par. 2). In par. 3 the practical solution for cells in electrolysis is discussed. First a nonstochastic model is considered, then the more realistic stochastic model. It is proved that an overhaul is not indicated after a certain space of time or after a certain increase in the costs, but when a certain absolute level of the costs (corresponding with a certain electrical tension) is reached irrespective of what went before. A formula (14) to this end is given. Attention is also paid to the problem of the numerical evaluation.     

The duration of homelessness: evidence from a national survey

This paper provides evidence on the determinants of the duration of homelessness. We use newly available data from a large-scale, comprehensive microeconomic survey to estimate a parametric survival model of the length of a spell of homelessness. We find that homeless spells are longer for persons with certain demographic characteristics (such as older men) and behavioral histories (for example, previous incarceration and a history of drug and alcohol abuse). Our results suggest that current eligibility criteria for receiving housing assistance, which give preference to drug-free, single women with young children, are unlikely to reduce homelessness substantially and in a cost-effective manner.     

离心泵检修之我见

作者对自己在离心泵的检修和维护方面的经验进行了归纳,特别是在离心泵常见故障方面,重点对排除故障的方法进行了论述。目的是能使同行在离心泵的检修方面有些参考及借鉴作用。