To resolve the issues of object group ' s life cycle management and fault tolerance properties management , an object factory model is designed to load the objects dynamically , two kinds of member creation patterns are introduced , a set of fault tolerance properties are defined according to the common characteristics of the fault - tolerant system , and moreover a hierarchy model is proposed to enable the dynamic and flexible configuration ( 1 )针对复制管理必须解决的对象组生命周期管理和容错属性配置管理，本文设计了一个能够动态部署和创建对象的对象工厂模型；引入了对用户透明程度不同的两种成员创建模式? ?基础设施控制和用户控制；并围绕容错系统的共有特征定义了一组容错属性，设计了层次化的属性配置模型，允许应用动态灵活地配置容错属性。
Conditional access system is the key to realize the increment of the dvb system and provides effective system management and subscriber control . it covers many advanced techniques such as system - scheduling management , network , digital coding & decoding , scrambling & descrambling , encrypting & decrypting , multiplexing , modulating & demodulating , set - top box , smart card and some practical database techniques , for example program management , subscriber management and charging management 条件接收系统( cas )是dvb系统实现增值的核心，能够提供有效的系统管理和用户控制，它集多种先进技术于一身，诸如：系统调度管理、网络技术、数字压缩编码、加解扰算法、加解密算法、复用器技术、调制解调技术、机顶盒技术、智能卡技术等，同时也涉及到用户管理、节目管理、收费管理等数据库应用技术。
The embedded running environment is platform software running in win ce embedded operating system , which executes system resource configuration , interprets and executes the control strategy and monitoring strategy files created by the integrated configuration software platform . the running environment is developed by evc + + , and divided into 嵌入式运行支撑环境是运行在wince上的一个平台软件,完成系统的资源配置,解释并执行集成组态开发环境生成的用户控制策略和监控策略文件等功能。
Being master control part , user controller stores , manages , display and query user information ; as slave control part , sub - user controller calculates and temporarily stores power sent from measuring module ; measuring module measures electric energy by using power meter ' s special circuit which simplifies circuit design and connects or breaks up power supply circuit by relay ; in order to transmitting data fast and exactly , rs - 485 communication standard is adopts between user controller and sub - user controller 主控部分用户控制模块可存储、管理、显示和查询用户电能信息；从控部分子用户控制模块计算并暂存电能测量模块输出功率数据；电能计量模块采用电度表专用厚膜电路hdb6进行电能计量，简化了电路设计，同时还利用继电器控制连接或断开用户的供电回路；在主从部分间采用rs - 485通信标准实现数据快速、准确的传输。
