BS EN 61703:2016提供了选定可靠性的数学表达式， 中定义的可用性、可维护性和维护支持措施 IEC 60050192:2015。此外，还介绍了IEC 60050中未涉及的一些术语- 192:2015. 它们与项目类别系统的各个方面有关（见下文）。根据IEC 60050-192:2015，可信性[192-01-22]是一个项目 按要求执行，项目[192-01-01]可以是单个零件、组件， 装置、功能单元、设备、子系统或系统。为了考虑数学约束，本标准将各个项目分开 作为一个整体考虑的项目（例如单个组件）和由多个组件组成的系统 个别项目。它提供了有关 系统以及单个项目，但更容易建模的单个项目是 对其维修方面进行了更详细的分析。 分别考虑以下项目类别:系统；单项:不可修复[192-01-12]；可修复[192-01-11]:恢复时间为零（或可忽略不计）；恢复时间非零。为了解释难以理解的可信性概念，请保持 标准自足式和尽可能简单的数学公式，如下 本标准使用基本数学模型来量化可信性度量:系统:状态转换模型；马尔可夫模型。单个项目:不可修复项目的随机变量（故障时间）；修复时间为零的可修复项目的简单（普通）更新过程；非零维修时间可修件的简单（普通）交替更新过程 恢复通过简单的例子说明了每个可信性度量的应用。本标准主要适用于硬件可靠性，但有许多术语及其应用 定义可能适用于包含软件的项目。交叉引用:IEC 60050-192:2015ISO 3534-1:2006IEC 61508EN 61508IEC 61511EN 61511IEC 61025EN 61078EN 61078IEC 61165EN 61165IEC 60605取代BS EN 61703:2002，该标准保持当前状态。购买本文件时，所有当前可用的修订均包含在本文件中。

BS EN 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.The following item classes are considered separately:Systems;Individual items:non-repairable [192-01-12];repairable [192-01-11]:with zero (or negligible) time to restoration;with non-zero time to restoration.In order to explain the dependability concepts which can be difficult to understand, keep the standard self-contained and the mathematical formulae as simple as possible, the following basic mathematical models are used in this standard to quantify dependability measures:Systems:state-transition models;Markovian models.Individual items:random variable (time to failure) for non-repairable items;simple (ordinary) renewal process for repairable items with zero time to restoration;simple (ordinary) alternating renewal process for repairable items with non-zero time to restoration.The application of each dependability measure is illustrated by means of simple examples.This standard is mainly applicable to hardware dependability, but many terms and their definitions may be applied to items containing software.Cross References:IEC 60050-192:2015ISO 3534-1:2006IEC 61508EN 61508IEC 61511EN 61511IEC 61025EN 61025IEC 61078EN 61078IEC 61165EN 61165IEC 60605Replaces BS EN 61703:2002 which remains currentAll current amendments available at time of purchase are included with the purchase of this document.