STEP标准数据库实现方式的研究

本文介绍ＳＴＥＰ标准的一种数据库实现方式，它基于作者自主开发的面向对象数据库管理系统－ＯＳＣＡＲ系统。文章从系统环境、数据类型、映射规则、操作、一致性、语言联编等六个方面概要阐述了ＳＴＥＰ标准数据库实现方式，并说明了它和ＳＴＥＰ中性文件、ＳＤＡＩ两种实现方式的关系。     

GHCAD：一个产品模型为基础的CAD／CAM集成系统

ＳＴＥＰ是关于产品数据表达和交换的国际标准，如何将ＳＴＥＰ的方法和规范应用于系统开发是解决计算机集成制造系统（ＣＩＭＳ）开发的关键问题之一。集成化ＣＡＤ／ＣＡＭ系统是ＣＩＭＳ的核心，实现将ＣＡＤ的工程设计功能和ＣＡＭ的制造功能的结合。本文介绍一个产品模型为基础的ＣＡＤ／ＣＡＭ集成系统－ＧＨＣＡＤ。系统采用ＳＴＥＰ的数据交换、建模思想，以产品模型为核心，通过ＳＴＥＰ的标准数据接口ＳＤＡＩ实现了系统的集成。     

STEP信息集成软件工具的设计和实现

ＳＴＥＰ是国际标准化组织ＩＳＯ正在组织开发的应用于计算机集成制造系统（ＣＩＭＳ）信息集成的产品数据表达与交换标准，ＳＴＥＰ不仅是一种规范，更是一种信息集成技术，本文以ＣＡＤ／ＣＡＰＰ／ＣＡＭ系统集成为背景，提出了ＳＴＥＰ信息集成支持工具ＥｘＴｒａ的设计和实现技术，该软件工具已成功且有效地应用于ＣＡＤ／ＣＡＰＰ／ＣＡＭ系统集成中。     

采用标准数据接口SDAI的CAD／CAM系统集成

如何将ＳＴＥＰ的方法和规范应用于系统开发是解决计算机集成制造系统（ＣＩＭＳ）开发的关键问题之一。集成化ＣＡＤ／ＣＡＭ系统是ＣＩＭＳ的核心，实现将ＣＡＤ的工程设计功能和ＣＡＭ的制造功能的结合。本文讨论通过ＳＴＥＰ的标准数据接口ＳＤＡＩ实现系统集成的集成方法，采用ＳＴＥＰ的数据交换、建模思想，实现了一个产品模型为核心的ＣＡＤ、ＣＡＭ集成系统－ＧＨＣＡＤ（高化ＣＡＤ）。     

BEE—DAE系统的设计与实现

ＢＥＥ—ＤＡＥ是一个基于数据库且支持ＳＴＥＰ／ＳＤＡＩ的数据交换软件系统。本文讨论了其设计和实现,包括设计思想、结构组织、以及数据访问接口和数据库与ＳＴＥＰ中性文件转换器等功能模型。该软件的开发为集成环境中ＣＡｘ系统的共享数据管理提供了方便和有效的工具。     

基于STEP的CAD/CAPP集成工具的研究

长期以来,ＣＡＤ／ＣＡＰＰ信息集成一直是ＣＩＭＳ系统的难点之一,且没有得到较好的解决。ＳＴＥＰ标准的发展和应用,使其成为ＣＡＤ／ＣＡＰＰ／ＣＡＭ系统信息集成的基础。随着越来越多的ＣＡＤ系统支持ＳＴＥＰ标准,开发基于ＳＴＥＰ的ＣＡＤ／ＣＡＰＰ集成工具成为当务之急。     

STEP标准与CAD／CAM数据管理

ＳＴＥＰ标准与ＣＡＤ／ＣＡＭ数据管理北京航空航天大学制造工程系张彦平香港城市大学ＪｏｈｎｎｖＰｏｏｎ一、引言ＳＴＥＰ（ＳｔａｎｄａｒｄｆｏｒｔｈｅＥｘｃｈａｎｇｅｏｆＰｒｏｄｕｃｔｍｏｄｅｌｄａｔａ）是国际标准化组织ＩＳＯＴＣ１８４／ＳＣ４正在组织开...     

A CONFIGURATION SYSTEM FOR FASTENER DESIGN（AN APPROACH TOWARDS COMPUTER AIDED CONCEPTUAL DESIGN）

ＡＣＯＮＦＩＧＵＲＡＴＩＯＮＳＹＳＴＥＭＦＯＲＦＡＳＴＥＮＥＲＤＥＳＩＧＮ（ＡＮＡＰＰＲＯＡＣＨＴＯＷＡＲＤＳＣＯＭＰＵＴＥＲＡＩＤＥＤＣＯＮＣＥＰＴＵＡＬＤＥＳＩＧＮ）ＧｕａｎｇＺｈｏｎｇ；ＭｉｋｅＤｏｏｎｅｒＡＣＯＮＦＩＧＵＲＡＴＩＯＮＳＹＳＴＥ...     

应用嵌套排序的并行CHOLESKY分解算法

应用嵌套排序的并行ＣＨＯＬＥＳＫＹ分解算法迟学斌（中国科学院计算中心）ＰＡＲＡＬＬＥＬＣＨＯＬＥＳＫＹＤＥＣＯＭＰＯＳＩＴＩＯＮＵＳＩＮＧＮＥＳＴＥＤＤＩＳＳＥＣＴＩＯＮＴＥＣＨＮＯＬＯＧＹ￥ＣｈｉＸｕｅｂｉｎ（ＣｏｍｐｕｔｉｎｇＣｅｎｔｅｒ，Ａｃａ...     

ADAPTIVE STRATEGIES FORNC MACHINING COMPOUND FREE-FORM SURFACES

ＡＤＡＰＴＩＶＥＳＴＲＡＴＥＧＩＥＳＦＯＲＮＣＭＡＣＨＩＮＩＮＧＣＯＭＰＯＵＮＤＦＲＥＥ－ＦＯＲＭＳＵＲＦＡＣＥＳＧａｏＳａｎｄｅ；ＺｈｏｕＹｕｎｆｅｉ；ＺｈａｎｇＸｉｎｆａｎｇ；ＺｈｏｕＪｉＡＤＡＰＴＩＶＥＳＴＲＡＴＥＧＩＥＳＦＯＲＮＣＭＡＣＨＩＮ...     

C++ in safety critical systems

The safety and reliability of software is influenced by the choice of implementation language and the choice of programming idioms. C++ is gaining popularity as the implementation language of choice for large software projects because of its promise to reduce the complexity and cost of their construction. But is C++ an appropriate choice for such projects? An assessment of how well C++ fits into recent software guidelines for safety critical systems is presented along with a collection of techniques and idioms for the construction of safer C++ code.     

DSM-CC编解码的C++实现

利用面向对象的方法，提出了在数字电视发送和接收系统中实现DSM-CC中数据下载协议的一种规律化的伪C代码到C 语言的映射规则，这一规则利用C 面向对象的语言特点，结合DSM-CC协议栈语义定义有很大相似性的特点，充分利用了多态和继承等面向对象的思想。利用这一规则，给出了一种自顶向下的DSM-CC的C 语言实现。这一实现具有对数据转盘（DC）和对象转盘（OC）兼容，可扩展性强，发送端（编码端）与接收端（解码端）通用的特点。     

C＋＋语言程序设计中学生工程能力的培养

本文通过C＋＋语言程序设计的实习,提出了目前存在的问题。通过分析其理论实践意义、具体解决方案和具体实施过程,论述了如何将学生工程能力的培养贯穿于C＋＋语言程序设计的教学中。     

The design and implementation of AspectC++

Aspect-Oriented Programming (AOP) is a programming paradigm that supports the modular implementation of crosscutting concerns. Thereby, AOP improves the maintainability, reusability, and configurability of software in general. Although already popular in the Java domain, AOP is still not commonly used in conjunction with C/C++. For a broad adoption of AOP by the software industry, it is crucial to provide solid language and tool support. However, research and tool development for C++ is known to be an extremely hard and tedious task, as the language is overwhelmed with interacting features and hard to analyze. Getting AOP into the C++ domain is not just technical challenge. It is also the question of integrating AOP concepts with the philosophy of the C++ language, which is very different from Java. This paper describes the design and development of the AspectC++ language and weaver, which brings fully-fledged AOP support into the C++ domain.     

C++反射机制的一种简单实现

讨论了C++反射机制的实现问题，介绍了反射机制的概念和分类，比较了向C++添加反射机制的可能性和方式，提出并分析了一种基于宏定义、模板和泛型机制的C++反射机制实现手段——“简单C++反射机制（Simple C++ Reflection SCR）”。     

Signatures: A language extension for improving type abstraction and subtype polymorphism in C++

C++ uses inheritance as a substitute for subtype polymorphism. We give examples where this makes the type system too inflexible. We then describe a conservative language extension that allows a programmer to define an abstract type hierarchy independent of any implementation hierarchies, to retroactively abstract over an implementation, and to decouple subtyping from inheritance. This extension gives the user more of the flexibility of dynamic typing while retaining the efficiency and security of static typing. With default implementations and views flexible mechanisms are provided for implementing an abstract type by different concrete class types. We first show how the language extension can be implemented in a preprocessor to a C++ compiler, and then detail and analyse the efficiency of an implementation we directly incorporated in the GNU C++ compiler.     

Making C++ objects persistent: The hidden pointers

C++ objects of types that have virtual functions or virtual base classes contain volatile (‘memory’) pointers. We call such pointers ‘hidden pointers’ because they were not specified by the user. If such C++ objects are made persistent, then these pointers become invalid across program invocations. We encountered this problem in our implementation of O++, which is a database language based on C++. O++ extends C++ with the ability to create and access persistent objects. In this paper, we describe the hidden pointers problem in detail and present several solutions to it. Our solutions are elegant in that they do not require modifying the C++ compiler or the semantics of C++. We also discuss another problem that arises because C++ allows base class pointers to point to derived class objects. C++ has emerged as the de facto standard language for software development, and database systems based on C++ have attracted much attention. We hope that the details and techniques presented will be useful to database researchers and to implementors of object-oriented database systems based on C++.     

基于LOTOS形式规范的目标实现

LOTOS形式规范的目标实现是协议设计中必不可少的阶段之一。该文对基于LOTOS的形式描述规范的实现方法进行了研究,包括目标实现环境的特点、实现中的空白因素、抽象模型到实现模型的转换、规范的最终目标实现,并对如何将LOTOS规范转换为C、C 语言实现进行了探讨。     

Arachne: a portable threads system supporting migrant threads onheterogeneous network farms

We present the design and implementation of Arachne, a threads system that can be interfaced with a communications library for multithreaded distributed computations. In particular, Arachne supports thread migration between heterogeneous platforms, dynamic stack size management, and recursive thread functions. Arachne is efficient, flexible, and portable-it is based entirely on C and C++. To facilitate heterogeneous thread operations, we have added three keywords to the C++ language. The Arachne preprocessor takes as input code written in that language and outputs C++ code suitable for compilation with a conventional C++ compiler. The Arachne runtime system manages all threads during program execution. We present some performance measurements on the costs of basic thread operations and thread migration in Arachne and compare these to costs in other threads systems     

An implementation of the SANE Virtual Processor using POSIX threads

The SANE Virtual Processor (SVP) is an abstract concurrent programming model that is both deadlock free and supports efficient implementation. It is captured by the μTC programming language. The work presented in this paper covers a portable implementation of this model as a C++ library on top of POSIX threads. Programs in μTC can be translated to the standard C++ syntax and linked with this library to run on conventional systems. The motivation for this work was to provide an early implementation on conventional processors as well as supporting work from programming FPGA chips to Grids.