安全语言PointerC的设计及形式证明

程序设计语言本身的安全性在高安全需求软件的设计和实现中起着基础作用.该文在用于系统级编程的安全语言的设计和性质证明方面,做了有益的尝试.作者设计了一个类C的命令式语言PointerC,其主要特点在于其类型系统中包含显式的副条件(side conditions),这些副条件本质上是约束程序语法表达式值的逻辑公式.该文证明了PointerC语言的安全性定理,即满足这些副条件的程序,在执行时不会违反语言的安全策略.为静态推理副条件中涉及指针的命题,作者已经提出了一种指针逻辑(pointer logic),文中证明了指针逻辑对操作语义是可靠的.     

Fast dynamic casting

We describe a scheme for implementing dynamic casts suitable for systems where the performance and predictability of performance is essential. A dynamic cast from a base class to a derived class in an object‐oriented language can be performed quickly by having the linker assign an integer type ID to each class. A simple integer arithmetic operation verifies whether the cast is legal at run time. The type ID scheme presented uses the modulo function to check that one class derives from another. A 64‐bit type ID is sufficient to handle class hierarchies of large size at least nine levels of derivation deep. We also discuss the pointer adjustments required for a C++ dynamic_cast. All examples will be drawn from the C++ language. Copyright © 2005 John Wiley & Sons, Ltd.     

Adding graphics to a high-level programming language

When graphics input/output capabilities are added to a programming language originally designed with a text stream input/output model, various design decisions affect the ease with which the graphics facilities are learned and used by applications programmers. In adding window system facilities to the Icon programming language, some design decisions were made very differently from the conventional wisdom, resulting in substantial benefits for programmers. In addition, some pre-existing Icon language features have proved to be useful in graphics programming.     

一种基于GPU的改进光线投射算法

针对传统光线投射算法计算量大、速度慢、在没有硬件加速情况下难以实时重建的问题,提出了一种基于GPU编程的快速计算重采样点值的光线投射算法。首先,设计一个GPU程序确定投射光线的终点与方向;其次,采用加速度步长采样方法确定重采样点的位置并利用快速复合插值方法计算重采样点的颜色值;最后,采用不透明度提前截止法进一步加速重建过程。实验结果表明,该方法计算复杂度低、执行效率高。在保证重建图像质量的同时,与现有基于CPU的光线投射算法相比,重建速度提高6倍,与基于GPU的传统光线投射算法相比,速度提高2倍。     

基于变约束规划模型的炼钢连铸动态调度

针对炼钢连铸生产过程中时常出现各种扰动, 采用人工调度存在反应慢、调度结果不优化的问题, 在分析各种调整方式基础上, 建立了在线调整非线性规划模型, 通过约束变化满足不同的调整方式要求, 并将模型转化为线性规划模型后对其进行求解. 在国内某大型钢厂应用结果表明: 采用该方法在缩短动态调度时间、减少钢水冗余等待时间、提高设备负荷率方面取得显著成效.     

An interpretation of typed OOP in a language with state

In this paper we give semantics toLoop, an expressive typed object-oriented programming language with updatable instance variables.Loop has a rich type system that allows for the typing of methods operating over an open-ended self type. We prove the type system given is sound;i.e., well-typed programs do not experience message not understood errors. The semantics ofLoop is given by a translation into a state-based language,Soop, that contains reference cells, records, and a form of F-bounded polymorphic type.Partially supported by NSF grant CCR-9109070Partially supported by AFOSR grant F49620-93-1-0169     

Towards a Programming Language for Interaction Nets

Interaction nets were introduced almost 15 years ago. Since then they have been put forward as both a graphical programming paradigm and as an intermediate language into which we can compile other languages. Whichever way we use interaction nets, a problem remains in that the language is very primitive. Drawing an analogy with functional programming, we have the λ-calculus but we are missing the functional programming language: syntactic sugar, language constructs, data-structures, etc. The purpose of this paper is to make a first step towards defining such a programming language for interaction nets.     

基于准时制的炼钢连铸组炉问题模型和算法

在满足炼钢连铸和热轧生产规程的基础上,综合考虑组炉余材和热轧工序对板坯浇铸的时间要求,将组炉问题归结为一个带时间约束的优化问题,建立了组炉问题的数学模型,采用改进遗传算法对模型求解,实例计算结果表明,基于改进遗传算法求解多约束条件下的组炉问题是有效的和可行的。     

“案例驱动”在“C语言程序设计”教学中的探索实践

本文结合应用型本科院校的特点,提出并探索了在"C语言程序设计"教学中采用"案例驱动"的教学方式。实践证明,在实际教学中应用"案例驱动"教学法,很大程度上增强了学生对"C语言程序设计"课程的兴趣,提高了学生用C语言解决实际问题的综合能力,取得了非常显著的教学成效。     

Type-safe relaxing of schema consistency rules for flexible modelling in OODBMS

Object-oriented databases enforce behavioral schema consistency rules to guarantee type safety, i.e., that no run-time type error can occur. When the schema must evolve, some schema updates may violate these rules. In order to maintain behavioral schema consistency, traditional solutions require significant changes to the types, the type hierarchy and the code of existing methods. Such operations are very expensive in a database context. To ease schema evolution, we propose to support exceptions to the behavioral consistency rules without sacrificing type safety. The basic idea is to detect unsafe statements in a method code at compile-time and check them at run-time. The run-time check is performed by a specific clause that is automatically inserted around unsafe statements. This check clause warns the programmer of the safety problem and lets him provide exception-handling code. Schema updates can therefore be performed with only minor changes to the code of methods. Edited by Matthias Jarke, Jorge Bocca, Carlo Zaniolo. Received September 15, 1994 / Accepted September 1, 1995     

Extending type systems in a library: Type-safe XML processing in C++

Type systems built directly into the compiler or interpreter of a programming language cannot be easily extended to keep track of run-time invariants of new abstractions. Yet, programming with domain-specific abstractions could benefit from additional static checking. This paper presents library techniques for extending the type system of C++ to support domain-specific abstractions. The main contribution is a programmable “subtype” relation. As a demonstration of the techniques, we implement a type system for defining type qualifiers in C++, as well as a type system for the XML processing language, capable of, e.g., statically guaranteeing that a program only produces valid XML documents according to a given XML schema.     

基于Linux系统分析计算机C语言编程技巧

C语言程序设计是高效计算机专业学生必修的一门基础课程,同时也是后续课程的入门课程,对于掌握基本计算机技术有着重要意义。尤其在Linux系统下,该系统在所有操作系统中占着重要地位,如何掌握计算机C语言编程技巧是当务之急。为此,本文重点探讨基于Linux系统分析计算机C语言编程技巧。     

Notes toward a standard object-oriented DDL and DML

Software developers seek a standard object-oriented database management system as a substrate on which to build object-oriented products. Convinced of the real value of object-oriented benefits, independent software vendors seek a platform to minimize development risk. A minimalist position is compared to the object-oriented database programming language position and the latter is shown to to be the cleanest but pragmatic considerations may intervene.     

Illustrating Client and Implementation Readability Tradeoffs in Ada and C++

The relative merits of Ada and C++ have fostered numerous discussions among software developers. With the release of Ada 95 and its object-oriented features, we expect these discussions to intensify, particularly given the increasing number of features for which there are implementations in both languages. In this paper, we compare Ada and C++ based on the readability of class and client implementations. We examine this issue using a case study. Our case study illustrates a partial tradeoff that exists between the readability of a class and the readability of its clients. This tradeoff depends on the degree to which overloading is used; extensive use of overloading adds to class complexity, although it increases client readability.     

Issues in the design of a parallel object-oriented language

This paper discusses the considerations that have played a role in the design of the language POOL2. This language integrates the structuring techniques of object-oriented programming with mechanisms for expressing parallelism. We introduce the basic principles of object-oriented programming and its significance for program development methodologies. Several approaches for integrating objects and parallelism are compared and arguments for the choices made in POOL2 are presented. We also explain why inheritance is not yet included in POOL2. A brief overview of the research in formal aspects of POOL is given. Finally we indicate some directions for future developments.     

用户化虚拟设计中的产品族描述语言PFL

介绍一种面向大规模定制的基于Web的用户化虚拟设计环境的基本框架，针对其中造型服务器中描述产品族结构的需要，提出用产品族描述语言建立产品族结构的方法，设计了相应的语法和语义结构，并构建了相应的解释器执行该语言并最终生成产品的虚拟模型．     

Design of an arabic programming language (ARABLAN)

It was observed that school children in Arab countries find difficulty in learning programming in a language other than their native language. There are only few Arabic programming languages in the literature; most of which are never or partially implemented. In this paper, we present the design of a new Arabic programming language (ARABLAN) which is planned to be implemented for use in teaching programming for school children in Arab countries.     

量子程序设计语言NDQJava

量子程序设计语言自1996年出现以来,颇受业界重视.在简述几种有代表性的量子程序设计语言之后,着重阐述自行设计之量子程序设计语言NDQJava之概貌,其中包括设计准则、语言风范、硬件平台、基本成分以及示例等.此外,还提及相关工作.     

C语言中循环结构程序课的教学设计与探讨

循环结构的程序设计是面向过程的程序设计课程的核心部分,掌握好循环结构的程序设计技术对学好此类课程至关重要。本文重点介绍了"C语言程序设计"中循环结构程序课的一种行之有效的教学方法和教学手段。     

C语言程序设计语法知识体系结构总结

本文就C语言程序设计知识体系结构进行深入的分析与归纳,提出C语言程序设计的语法方面的知识体系结构。首先,讨论知识体系结构中各概念的定义;其次,分别给出C语言的语法知识体系和程序设计的语法知识体系。为设计C语言程序设计题库提供理论基础。