面向对象软件自动化系统JDAUTO＼0

本文介绍了面向对象经系统ＪＤＡＵＴＯ／０的设计与实现，ＪＯＯＳＬ是一种面向对象软件形式规约语言，基于它，实现了概要设计到详细的自动工具ＰＤＡＵＴＯ和详细设计到Ｃ＋＋代码的自动转换工具ＤＤＡＵＴＯ．     

一种8031双重软件WATCHDOG设计

本文简述了在８０３１单片机应用中的一种双重ＷＡＴＣＨＤＯＧ的设计思想，着重介绍了了通过定时器Ｔ０和Ｔ１形成的两级中断源实现ＷＡＴＣＨＤＯＧ的设计方法。     

结合形式化的面向对象设计方法与支撑系统

为了有效地结合形式化和非形式化设计方法各自的优点,克服其不足之处,以尽可能保证软件设计的质量与可靠性,文章提出了一种将形式化方法与非形式化的面向对象设计方法ＨＯＯＤ（ｈｉｅｒａｒｃｈｉｃａｌｏｂｊｅｃｔ－ｏｒｉｅｎｔｅｄｄｅｓｉｇｎ）相结合的途径,并介绍了其机器支撑环境的设计与实现．该途径在对层次式面向对象设计方法ＨＯＯＤ进行必要扩充的基础上,有机地集成了Ｚ语言等形式规约技术．支持这一途径的支撑环境提供了一套方便灵活的图形构筑工具、语法制导的形式语言与文本编辑工具,以及自动检查机制等．     

信息系统需求分析的面向对象层次分析方法及应用

文章将面向对象分析（ＯＯＡ）,结构化分析（ＳＡ）和数据结构分析（ＤＳＡ）方法相结合,提出了一种信息系统需求分析的面向对象层次分析方法（ＯＯＨＡ）,给出了对象的属性和方法定义以及需求分析的形式化表示方法。使用ＯＯＨＡ方法进行需求分析,层次清晰,对象关系明确,容易实现问题空间到解空间的映射。     

基于AD HOC网络的寻径方法初探

目前，对于ＡＤ ＨＯＣ网络的研究已成为无线网络通信的重点之一，对于这种网络的寻路方法的探讨也越来越深入，但是由于ＡＤ ＨＯＣ网络本身固有的特点，使得对竽它的寻路方法的研究较为困难，本文在分析了目前最新的几种寻路方法后，指出了它们的优缺点，并提出一种新的解决方案。     

DOS5.0下对子目录隐含加密的实施策略

对子目录隐含加密的一些常规方法在ＤＯＳ５．０下失效，为此本文提出了一种全新的加密方法，它能有效地避开ＤＯＳ５．０的ＤＯＳＳＨＥＬＬ以及ＰＣＴＯＯＬＳ、ＣＰＡＶ等等诸多软件的搜索，起到较好地隐含加密效果。     

SDH系统中OSI／RM的研究与ACSE实现

本文首先介绍了ＳＤＨ的技术背景，根据ＯＳＩ／ＲＭ给出了ＳＤＨ网络管理协议栈ＳＤＨＤＣＣ，从总体上提出了实现ＯＳＩ／ＲＭ的两种方案，即过程实现和进程实现方式。综合两种实现方式给出了ＳＤＨ网络系统的软件设计方案。最后，以应用层的ＡＣＳＥ为例，具体地给出了一个模块设计和实现框架。     

扁球壳的边界元分析的一种简便方法

扁球壳的边界元分析的一种简便方法龙述尧，蒯行成，李家宝，陈军（湖南大学）ＡＣＯＮＣＩＳＥＭＥＴＨＯＤＯＦＢＯＵＮＤＡＲＹＥＬＥＭＥＮＴＡＮＡＬＹＳＩＳＦＯＲＳＨＡＬＬＯＷＳＰＨＥＲＩＣＡＬＳＨＥＬＬＳ￥ＬｏｎｇＳｈｕ－ｙａｏ；ＫｕａｉＸｉｎｇ－ｃｈｅ...     

综述以太网

以太网,英文名为Ｅｔｈｅｒｎｅｔ,是当今世界上应用范围最广的一种网络技术。它最早起源于夏威夷大学。６０年代末,该校的ＮｏｒｍａｎＡｂｒａｍｓｏｎ及其同事为了将校内的ＩＢＭ３６０主机与分布在其它岛上的终端相连接而开发了一个无线电系统－ＡＬＯＨＡ。ＡＬＯＨＡ系统是一个争用型网络,在它身上已经体现了以太网的设计思想,即信道共享和信道争用。１９７２年,ＢｏｂＭｅｔｃａｌｆｅ和ＤａｖｉｄＢｏｇｇｓ在Ｘｅｒｏｘ公司的ＰＡＲＣ（Ｐａｌｏ　ＡｌｔｏＲｅｓｅａｒｃｈ　Ｃｅｎｔｅｒ,Ｐａｌｏ　Ａｌｔｏ研究中心）设计…     

VHDL与电子自动化

随着电子设计自动化（ＥＤＡ）时代的到来，传统的硬件设计方法已经无法满足人们的要求了，ＶＨＤＬ语言作为一种高级硬件描述语言，由于它能以形式化的方式描述数字系统，从而大部分繁琐的工作可以由计算机来完成，而设计师能专注于整个系统的设计。ＶＨＤＬ的出现为电子设计自动化（ＥＤＡ）的发展打下了坚实的基础，也给硬件设计领域带来一场革新。本文就此介绍了ＶＨＤＬ语言的基本构成和语句，及使用ＶＨＤＬ语言设计的优点。     

HRT-HOOD: A structured design method for hard real-time systems

Most structured design methods claim to address the needs of hard real-time systems. However, few contain abstractions which directly relate to common hard real-time activities, such as periodic or sporadic processes. Furthermore, the methods do not constrain the designer to produce systems which can be analyzed for their timing properties. In this article we present a structured design method called HRT-HOOD (Hard Real-Time Hierarchical Object Oriented Design). HRT-HOOD is an extension of HOOD, and includes object types which enable common hard real-time abstractions to be represented. The method is presented in the context of a hard real-time system life cycle, which enables issues of timeliness and dependability to be addressed much earlier on in the development process. We argue that this will enable dependable real-time systems to be engineered in a more cost effective manner than the current practice, which in effect treats these topics as performance issues. To illustrate our approach we present a simple case study of a Mine Drainage Control System, and show how it can be designed using the abstractions presented in the article.HOOD is a trademark of the HOOD User Group.The work has been supported, in part, by the European Space Agency (ESTEC Contract 9198/90/NL/SF) and by the UK Defence Research Agency (Contract Number 2191/023).     

一种层次化面向对象设计方法

面向对象系统平坦式的体系设计结构,以及它本身对实时、并发行分布等特征的支持的欠缺,使它在相关领域的应用受到了一定的限制。层次化面向对象设计方法（HOOD）是针对实时嵌入式系统设计而定制的。在OOD的基础上引入了层次化的思想,并把对实时、并发和分布等特性的支持无缝地集成在一起,使之更适合实时嵌入式系统的设计。     

The Algebraic Framework for Object-Oriented Systems

Category Theory is introduced as the mathematical model for object-oriented systems which are distributed, heterogeneous, real-time, embedded, and open-ended. Each object can be represented as an algebra. A collection of algebras with morphisms form a category if they satisfy some conditions. After a brief introduction of categorical concepts which are needed to formulate the framework for object-oriented systems, they are explicated in terms of objects. Then some system design methodologies such as SADT, JSD, MASCOT 3, OOD, HOOD, MOON, ADM 3, and Petri nets are examined in the categorical framework and classified into four groups: functional, process-based, object-oriented, and net-based. Combining theoretical and practical results, the interactive system design tool OBJ-NET is briefly introduced.     

Integrating structured OO approaches with formal techniques for the development of real-time systems

The use of formal methods in the development of time-critical applications is essential if we want to achieve a high level of assurance in them. However, these methods have not yet been widely accepted in industry as compared to the more established structured and informal techniques. A reliable linkage between these two techniques will provide the developer with a powerful tool for developing a provably correct system. In this article, we explore the issue of integrating a real-time formal technique, TAM (Temporal Agent Model), with an industry-strength structured methodology known as HRT-HOOD. TAM is a systematic formal approach for the development of real-time systems based on the refinement calculus. Within TAM, a formal specification can be written (in a logic-based formalism), analysed and then refined to concrete representation through successive applications of sound refinement laws. Both abstract specification and concrete implementation are allowed to freely intermix. HRT-HOOD is an extension to the Hierarchical Object-Oriented Design (HOOD) technique for the development of Hard Real-Time systems. It is a two-phase design technique dealing with the logical and physical architecture designs of the system which can handle both functional and non-functional requirement, respectively. The integrated technique is illustrated on a version of the mine control system.     

Organizing the description of a relational data base

The design and implementation of the data structures used within a software system such as a compiler, an operating system or a data base management system are fundamental to the development of that system. Unfortunately, there are very few standard techniques for designing such data structures and for structuring the software used to support them. This paper proposes that it is possible to use data base techniques to design and implement such data structures. For this reason, it describes a methodology which is used to design large relational data bases, and then demonstrates how the methodology was modified and used to design the internal data structures of a relational data base management system. This paper concludes that this approach produces data structures which are better understood and easier to modify than those resulting from an ad-hoc approach.     

Knowledge-based approach and system for assembly-oriented design,Part II: the system implementation

Assembly is one of the most important stages for product development. Assembly-oriented design (AOD) is a new approach to designing assemblies, which uses a number of design and analysis tools to help the designer plan out and analyze candidate assembly schemes prior to having detailed knowledge of the geometry of the parts. Using this approach, many assembly schemes can be inexpensively evaluated for their ability to deliver the important characteristics of the final product. This research proposes a knowledge-based approach and develops an expert design system to support top-down design for assembled products. The presentation of research report is divided into two parts: the knowledge-based approach (Part I) and the knowledge-based expert design system (Part II). This paper is the second part of the report (Part II). It will focus on the development of knowledge-based expert design system for assembly oriented design. The knowledge-based assembly oriented design system, i.e., the assembly oriented design expert system (AODES) is constructed to integrate assembly modeling and design, assembly planning, assemblability analysis and evaluation within a concurrent engineering environment. This intelligent system is implemented by integrating object-oriented representation, constraint-based modeling, rule-based reasoning, truth maintenance, and interfacing to database management system and CAD module, in which fuzzy logic based knowledge representation and inference technique are also applied to deal with uncertain data and knowledge in the design process. The developed system differs from the existing systems adopting part-first bottom-up modeling technique, in which a comprehensive intelligent framework is used for assembly modeling and design in a top-down manner from the conceptual level to the detailed level. It is able to help obtain better design ideas, provide users with suggestions so as to create and improve a design, and therefore give users the possibility to assess and reduce the total production cost at an early stage during the design process. Through the use of the system, the concurrent engineering knowledge can be effectively incorporated into the assembly design process in an integrated manner. A case assembly design shows that the intelligent modeling and design system is feasible.     

Modularity the key to system growth potential

General Electric's Apollo Systems has developed several information systems over the last eight years in support of the Apollo project. The expertise gained in these development efforts has shown the efficiency of a modularized approach to retrieval system design Systems analysts and programmers who design and build these systems should follow the normal systems engineering approach of requirements definition, system design, system implementation, test and verification and operational installation. Short-cutting any one of these phases leads to greater effort in one of the later phases, usually with a longer over-all schedule or greater developmental cost Project management, too, is a major factor in the success of such systems. The tracking of critical milestones in the schedule, consistent and up-to-date documentation, and comprehensive test and verification plans are necessary to a controlled approach to systems implementation Finally, the benefits of such an approach are reduced cost and implementation time, along with simplification of system maintenance, standardized software, adaptability to new environments, and a potential for continued growth to meet users' ever-expanding needs.     

Virtual engineering at work: the challenges for designing mechatronic products

The product race has become an innovation race, reconciling challenges of branding, performance, time to market and competitive pricing while complying with ecological, safety and legislation constraints. The answer lies in “smart” products of high complexity, relying on heterogeneous technologies and involving active components. To keep pace with this evolution and further accelerate the design cycle, the design engineering process must be rethought. The paper presents a mechatronic simulation approach to achieve this goal. The starting point is the current virtual prototyping paradigm that is widely adopted and that continues to improve in terms of model complexity, accuracy, robustness and automated optimization. Two evolutions are discussed. A first one is the extension to multi-physics simulation answering the design needs of the inherent multi-disciplinarity of “intelligent” products. Integration of thermal, hydraulic, mechanical, haptic and electrical functions requires simulation to extend beyond the traditional CAD-FEM approach, supporting the use of system, functional and perception models. The second evolution is the integration of control functions in the products. Where current industrial practice treats mechanical system design and control design as different design loops, this paper discusses their integration in a model-based design process at all design stages, turning concepts such as software-in-the-loop and hardware-in-the-loop into basic elements of an industrial design approach. These concepts are illustrated by a number of automotive design engineering cases, which demonstrate that the combined use of perception, geometric and system models allows to develop innovative solutions for the active safety, low-emission and high-comfort performance of next-generation vehicles. This process in turn poses new challenges to the design in terms of the specification and validation of such innovative products, including their failure modes and fault-tolerant behaviour. This will imply adopting a model-based system engineering approach that is currently already common practice in software engineering.