Towards the automated operations of large distributed satellite systems. Part 2: Classifications and tools

Recent developments have seen a trend towards larger constellations of spacecraft, with some proposals featuring constellations of more than 10.000 satellites. While similar concepts for large constellations already existed in the past, traditional satellite deployments hardly ever feature groups of more than 100 satellites. This trend towards considerably larger satellite numbers originates from non-traditional design and operations of spacecraft by non-traditional space companies. The evolution in the space sector, precipitated by new players, is often referred to as “Space 4.0” or “New Space”. It necessitates a rethinking of the way satellites and satellite constellations are planned, designed, and operated. New operational paradigms are needed to enable automatic, optimal task definition, and scheduling in a holistic approach.This is the second of two companion papers that investigate the operations of distributed satellite systems. This second article investigates the classification of distributed satellite systems and evaluates commercial tools for automated spacecraft operations, whereas the first article performed a survey of conventional and “new space”operations of spacecraft constellations.Classification metrics for constellations are derived and evaluated with respect to their informative value concerning the operation, the automation, and the scalability of the constellation. The proposed classification system is applied to the Dove and RapidEye constellation and allows for a comparison between the presented automation approaches. Commercial tools for automated spacecraft operations are evaluated for several mission task elements, such as orbit control, orbit maintenance, and collision avoidance. Subsequently, the trends, benefits, and standardization needs for operational automation are identified.     

Ada软件测试结果分析与可视化（TRAV）

论述了Ａｄａ软件测试结果分析系统的功能，它的方案设计以及界面风格，此系统是集成化的Ａｄａ软件测试与分析系统中的主要工具之一，它不仅能够帮助用户分析与测试软件系统，还能对软件系统的理解和维护提供有力的支持。     

Research and Development of Ceramic Cutting Tools in China

The research and development of various classes of ceramic cutting tools in China are described,because manufacturing efficiency is fundamental to the growth of China's economy.     

数控车削加工的参考点及对刀分析

本文深刻分析了数控车床的对刀原理和对刀涉及的基本概念,从工件坐标系建立与对刀关系的角度展开论述,说明吩刀的实质,以及常用刀具的对刀方法与步骤。     

对象Petri网模型的并发软件仿真技术的研究

并发软件的性能评价是提高软件开发质量的重要手段之一．本文重点讨论了将面向对象与Ｐｅｔｒｉ网相结合的思想用于并发软件开发中的系统建模,以及基于对象Ｐｅｔｒｉ网（ＯＰＮ）的并发软件系统的仿真技术,同时,也探讨了实现一个基于ＯＰＮ的动态仿真工具所面临的关键技术和解决方法．实践结果表明,文中讨论的实现机制与处理方法是有效和可行的．     

面向对象程序可视化类图的逆向自动生成

研究了逆向构造程序类模型的基本规则, 并且提出了一种可以自动绘制的、基于继承关系的层次型类图结构(inheritance-layered class diagram).在这种层次型类图上,可以清晰地展示程序中的对象类及其相互之间的继承关系、组成关系和关联关系等,并可以直观方便地对程序中定义的对象类进行各种相关性或依赖性分析.文中还介绍了一个根据上述规则和方案实现的实用工具SafePro/Re-OM.     

UML软件开发过程和支持环境研究

从当前对软件工程过程的需求出发,结合软件工程领域的最新成果统一建模语言UML(Unified Modeling Language),重点讨论了适应需求变化的迭代式软件开发过程,提出了柔性软件开发模型.在此研究的基础上,设计了集成化UML软件开发环境的框架,指出其组成应包括UML可视化建模系统、UML模拟系统、UML代码生成系统和UML逆向变换系统4个部分,并提出了需要解决的问题.     

基于Petri网的CASE全集成机制的研究

为实现全集成的环境订成机制，提出了基于Ｐｅｔｉｒ网的超文本形式模型和面向对象Ｐｅｔｒｉ网，Ｐｅｔｉｒ网的引入不仅可以统一ＣＡＷＥ环境的数据集成，控制集成和表示集成，而且可利用已有Ｐｅｔｉｒ网理论对集成环境进行性能评价。     

家族企业战略管理及其启示——基于国外学者的论点

家族企业战略管理是家族企业可持续成长的一个重要因素。基于国外学者的论点,从家族企业资源、家族企业战略决策、家族企业战略类型和家族企业战略工具这四个方面做出评述。在此基础上,紧密结合家族企业治理特性和治理维度,初步建立了家族企业战略管理理论模型,并提出对我国家族企业战略管理实践的启示。     

LVDT刀具在线检测仪在超精密车削加工中的应用

介绍了一种LVDT刀具在线检测仪,用于超精密车削中刀具的精密对刀及刀尖圆弧半径测量。重点介绍了该装置的工作原理、组成部分及在超精密车削中的具体应用。