Investigating the Desirability of Navy Aircraft Service Life Extension Programs

Building on prior work on optimal replacement of aging aircraft, this paper presents three methodologies to evaluate prospective aviation Service Life Extension Programs (SLEPs) and applies these methodologies to US Navy F/A-18E/F data. While considerable uncertainty remains as to the values of key parameters (e.g. the cost of F/A-18E/F SLEPs), the preponderance of the evidence available at this juncture favors undertaking SLEPs on F/A-18E/Fs rather than replacing them with new Joint Strike Fighters.     

软件可靠性的过程仿真技术

以软件研制的生命周期为背景,探讨利用仿真模型对软件可靠性进行研究的方法．文章阐述了仿真模型分析方法与传统的模型分析方法的不同之处,通过对软件可靠性过程的分析,设计了一个基本的仿真器结构,由此考察引发失效行为的各种故障因素及其对软件可靠性的影响．     

Life cycle costs for decision support ‐ a study of the various life cycle costs used at different levels of defence policy and management∗

Debates on many aspects of defence economics ‐ on the scale of defence expenditure, on the allocation of that expenditure to various military capabilities, and on the selection of equipment offering the best value for money ‐ are bedevilled by misunderstandings and misconceptions about the costs of defence equipment. This paper seeks to improve understanding of defence equipment costs by defining a hierarchy of defence equipment within which the direct and indirect life cycle costs of defence equipment may be allocated at different levels. Having reviewed the direct and indirect components of the life cycle cost, this paper then shows how different costing studies for different purposes require different approaches to life cycle costing, and that there is no unique life cycle cost which can be assigned to one particular item of defence equipment. There is instead a range oflife cycle costs, each of which is appropriate for a particular study, and it is important that a quoted cost of an item of defence equipment should be used only in the pertinent circumstances. The paper is written from a UK perspective and accordingly uses British nomenclature, but its principles should be relevant to defence cost studies in other nations.     

寿命分布的参数Bootstrap拟合优度检验方法

拟合优度检验在统计和可靠性等领域具有非常重要的地位,基于参数Bootstrap重采样的思想,对未知参数的常用寿命分布进行拟合优度检验。数值仿真结果表明,相对于传统的经验分布函数检验,这种基于参数Bootstrap的拟合优度检验具有更高的功效,特别是在小样本的情况下,优势明显。     

数据拟合加速寿命试验智能优化设计

加速寿命试验方案的优劣,直接影响着试验的成本、效益和试验结果的准确性,因此有必要对试验方案进行优化设计,寻找最佳应力水平和试样分配比例,使加速寿命试验的结果最准确、代价最小.利用目标函数的连续性,提出一种基于离散数据的拟合方法,将加速寿命试验的优化设计转化为显函数的约束极值求解问题,然后将智能优化算法应用到加速寿命试验...     

Statistical analysis of exponential lifetimes under an adaptive Type‐II progressive censoring scheme

In this article, a mixture of Type‐I censoring and Type‐II progressive censoring schemes, called an adaptive Type‐II progressive censoring scheme, is introduced for life testing or reliability experiments. For this censoring scheme, the effective sample size m is fixed in advance, and the progressive censoring scheme is provided but the number of items progressively removed from the experiment upon failure may change during the experiment. If the experimental time exceeds a prefixed time T but the number of observed failures does not reach m, we terminate the experiment as soon as possible by adjusting the number of items progressively removed from the experiment upon failure. Computational formulae for the expected total test time are provided. Point and interval estimation of the failure rate for exponentially distributed failure times are discussed for this censoring scheme. The various methods are compared using Monte Carlo simulation. © 2009 Wiley Periodicals, Inc. Naval Research Logistics, 2009     

基于生命周期理论的军事环境安全策略

探讨了军事环境安全概念,并运用生命周期理论对国家军事环境安全的保障措施和宏观策略进行了初步研讨。军事活动一般可分为计划规划、具体实施和事后评价3个阶段。为了在新形势下更加经济、高效地保障国家军事环境安全,首先要加大军事活动环境影响评价力度、采用对环境破坏小的战法并在军购中推行环境准入制,即尽量从源头上控制重大环境问题出现。考虑到战争的特殊性,需要在战前预先储备必要的生态环境修复技术。     

舰船动力装置经济性的概念、模型及其应用

讨论舰船动力装置经济性的概念、度量指标及计算模型．然后,就其在动力装置的设计参数优选、机型选择和技术状态评定等方面的应用作了讨论．