可靠性、可用性、维护性和维护支持术语的数学表示式

[中文适用范围]： 本国际标准为 IEC 60050-192:2015 中定义的选定可靠性、可用性、维修性和维修支持措施提供数学表达式。此外，它还介绍了 IEC 60050-192:2015 未涵盖的一些术语。它们与系统或物品类别的方面有关（见下文）。根据 IEC 60050-192:2015，可靠性（[192-01-22]）是物品按要求执行任务的能力，而物品（[192-01-01]）可以是单个部件、组件、设备、功能单元、设备、子系统或系统。为了考虑数学约束，本标准将物品分为作为整体的单个物品（例如单个组件）和由几个单个物品组成的系统。它提供了针对系统和单个物品的数学表达式的一般考虑，但单个物品（更容易建模）在修复方面进行了更详细的分析。考虑的以下物品类别是单独处理的：系统；单个物品：不可修复 [192-01-12]；可修复 [192-01-11]：i) 修复时间为零（或可忽略不计）；ii) 修复时间不为零。为了解释可能难以理解的可靠性概念，保持标准的自包含性，并使数学公式尽可能简单，本标准采用以下基本数学模型来量化可靠性指标：系统：状态转移模型；马尔可夫模型。单个物品：不可修复物品的随机变量（失效时间）；零修复时间的可修复物品的简单（普通）更新过程；非零修复时间的可修复物品的简单（普通）交替更新过程。每个可靠性指标的应用均通过简单示例进行说明。本标准主要适用于硬件可靠性，但许多术语及其定义也可应用于包含软件的物品。 [外文原描述]： IEC 61703:2016 provides mathematical expressions for selected reliability, availability, maintainability and maintenance support measures defined in IEC 60050­192:2015. In addition, it introduces some terms not covered in IEC 60050-192:2015. They are related to aspects of the system of item classes (see hereafter). According to IEC 60050-192:2015, dependability [192-01-22] is the ability of an item to perform as and when required and an item [192-01-01] can be an individual part, component, device, functional unit, equipment, subsystem, or system. To account for mathematical constraints, this standard splits the items between the individual items considered as a whole (e.g. individual components) and the systems made of several individual items. It provides general considerations for the mathematical expressions for systems as well as individual items but the individual items which are easier to model are analysed in more detail with regards to their repair aspects. This standard is mainly applicable to hardware dependability, but many terms and their definitions may be applied to items containing software. This second edition cancels and replaces the first edition published in 2001. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: - standard made as self containing as possible; - item split between individual items and systems; - generalization of the dependability concepts for systems made of several components [introduction of the conditional failure intensity (Vesely failure rate); - introduction of the state-transition and the Markovian models; - generalization of the availability to production availability]; - introduction of curves to illustrate the various concepts. Keywords: mathematical expressions for dependability