UML与SDL结合使用的研究

在本文中我们探索如何将统一建模语言(UML)与由国际电信联盟(ITU)标准化了的规格与描述语言(SDL)结合在一起使用．在研究中，我们发现SDL用户可以从UML中获得益处，同样UML用户也可以利用SDL的优点．特别是对于实时系统的开发，我们应当用UML进行系统的需求分析，使用SDL进行系统设计．     

SDL语言动态语义模型的研究

介绍了SDL系统规范，基于通信扩展有限状态机CEFSM的SDL进程。系统最重要的属性是行为，动态语义模型用元进程描述系统可观察的行为。研究了ITUZ．100建议附件F中元进程的划分，提出一种新的元进程定义，并举例描述了SDL系统的动态语义模型。     

Applying techniques and tools for the performance engineering of SDL systems

The integration of performance evaluation techniques into the SDL method is an important task. In particular in the area of telecommunications and distributed systems where product families have to be maintained for many years, performance should be considered from the very beginning of system design. This paper demonstrates how performance engineering can be successfully applied. Firstly, an SDL specification of TCP/IP is used to derive a performance model that includes the original SDL system as well as additional constructs describing the consumption of time and resources. Different implementation variants have been evaluated in experimental scenarios. Secondly, the application of a specification-driven monitoring technique to the same SDL specification of TCP/IP is described. The case study shows how the functional and temporal behaviour of an implementation derived from an SDL specification can be analysed and improved by monitoring the running system. The two approaches, modelling and monitoring, are supplementary to each other. This paper provides arguments that the systematic application of specification-driven performance engineering will result in major savings of time and money in later development phases and for later system releases.     

The SDL pattern approach – a reuse-driven SDL design methodology

There are several SDL methodologies that offer full system life-cycle support. Only few of them consider software reuse, not to mention high-level reuse of architecture and design. However, software reuse is a proven software engineering paradigm leading to high quality and reduced development effort. Experience made it apparent that – beyond the more traditional reuse of code – especially high-level reuse of architecture and design (as in the case of design patterns or frameworks) has the potential of achieving more systematic and widespread reuse. This paper presents the SDL pattern approach, a design methodology for distributed systems which integrates SDL-based system development with the pattern paradigm. It supports reuse of design knowledge modeled as SDL patterns and concentrates on the design phase of SDL-based system development. In order to get full life-cycle support, the pattern-based design process can be integrated within existing SDL methodologies.     

基于SDL语言的通信协议系统设计方法

SDL语言是软件工程中的系统功能结构的描述语言方法。该文讨论了SDL语言的基本概念,特别是SDL对通信协议工作机制和过程的形式化分析及表示,分析了对电话语音查询系统的协议流程和工作机制的应用,为通信协议的设计和仿真、测试提供了一种有效的方法。     

基于SDL的H.264流媒体播放系统

针对目前广泛使用的H．264标准,设计了一种基于SDL和ffmpeg的流媒体播放系统．将经过RTP封装的流媒体信息解除封装处理后,利用ffmpeg良好的解码能力对数据进行解码,之后再利用SDL优异的视频性能进行实时显示,并同时将流媒体数据保存在本地以供随时调用．实验证明,该播放系统解码播放的实时性出色,画质良好,此外凭借ffmpeg和SDL的跨平台特性,系统具有良好的移植性和拓展性,适用于嵌入式设备和手机平台．     

基于SDL模式的通信协议开发

研究了设计模式和形式化描述语言SDL相结合的SDL模式技术,分析了通信协议开发中存在的两类SDL模式:结构模式和行为模式,提出了一种基于SDL模式开发通信协议软件的方法,并通过PPP协议的开发实践验证了该方法的可行性.该方法可以有效的重用已有成功的软件开发成果,减少通信协议软件开发难度,缩短系统开发周期,提高软件质量.     

动画剧本描述语言SDL／A的设计与实现

本文介绍了基于时序逻辑的动画描述模型和基于此模型设计的动画剧本描述语言ＳＤＬ／Ａ．这种语言具有便于动画设计各个层次的描述、能够描述设计的逐步求精过程、能描述动画中的各种抽象对象以及角色间动作的同步等特点，并易于将这种基本的通用的剧本描述语言集成到一个功能强大的ＣＡＳＥ环境－ＸＹＺ系统之中．本文主要介绍了ＳＤＬ／Ａ语言的设计思想和实现技术.     

Leveraging a personalized system to improve self-directed learning in online educational environments

Many students who participate in online courses experience frustration and failure because they are not prepared for the demanding and isolated learning experience. A traditional learning theory known as self-directed learning (SDL) is a foundation that can help establish features of a personalized system that helps students improve their abilities to manage their overall learning activities and monitor their own performance. Additionally, the system enables collaboration, interaction, feedback, and the much-needed support from the instructor and students' peers. A Web 2.0 social-technology application, MediaWiki, was adopted as the platform from which incremental features were developed to utilize the fundamental concepts of SDL. Students were able to customize content by setting specific learning goals, reflecting on their learning experiences, self-monitoring activities and performances, and collaborating with others in the class. SDL skills exist to some degree in all learners, this study finds that students' SDL abilities can improve when a course adopts a personalized and collaborative learning system that enables the students to be more proactive in planning, organizing, and monitoring their course activities.     

Embedded system design with ada as the system design language

Recent research in software engineering has produced a number of techniques for structuring an understanding of systems. Many of these techniques are applicable to the design of embedded computer systems and produce designs whose structures are easily expressible in the ada language. This language is itself structured so that the design of a system can be expressed independently of its implementation. Thus ada can be a useful system design language (SDL) with these techniques. This paper describes the software design problem in the development of embedded computer systems. It shows how ada can be used as an SDL, as well as a system implementation language. The essential point is that as an SDL ada encourages designers to use recent theory to develop better structures for their systems, and its subsequent use to implement the systems preserves those structures in the product.     

基于SDL语言的VxWorks嵌入式操作系统的具体实现

随着嵌入式系统通信协议的复杂性急剧提高,迫使工程师们去寻找一种效率更高的设计工具来完成工作,而SDL作为一种图形化的设计满足了这种需要,因此RTOS-SDL相结合的思路应运而生。主要说明了把SDL应用在VxWorks中的步骤和具体实现中遇到的问题,以及编程中的一些技巧。而且经试验表明,采用这种方法不但可以完成原先的需求,而且还可以在有限的时间内完成程序的编写,提高工作效率,对于SDL和嵌入式系统的结合具有很好的参考价值。     

SDL支撑系统

ＳＤＬ是一种主要用于对电信系统性能制定确切的功能规格和描述的国际标准语言．本文描述了以ＣＣＩＴＴＳＤＬ’８８为标准，基于图形核心系统（ＧＫＳ）设计实现的ＳＤＬ支撑系统（３Ｓ），包括ＳＤＬ的图形方式（ＳＤＬ／ＧＲ）的文档录入和编辑工作、对录入的ＳＤＬ／ＧＲ文档进行正确性检查和将ＳＤＬ／ＧＲ文本翻译到文字短语方式表达的ＳＤＬ／ＰＲ文本等几部分．此工作的完成对于使用图形方式描述计算机系统，然后翻译到高级语言提供了可能．     

Structural design language for coupled knowledge-based systems

A Structal Design Language (SDL) has been developed in INTERLISP environment for building coupled knowledge-based expert systems for integrated design of a class of structures. The integrated design includes the preliminary design, structural analysis, design of members, design of connections, and computer-aided drafting of the final design. The complex body of knowledge needed for detailed design of a structure is fractionated into smaller and more manageable knowledge sources which are organized into a hierarchy of cooperating conceptual specialists. SDL provides a multiwindow graphics interface capable of displaying both the orthographic and isometric views of the frame structure and beam-column connections. A three-dimensional face frame representation sentation is used for the graphic display of the beam-column connections. SDL has been used to develop a prototype knowledge-based system for integrated design of steel building structures consisting of moment-resisting frames.