Linear and non-linear programming software validity

The numerical software users are often perturbed by accuracy problems imputable to the rounding errors generated by computer hardware. M. La Porte and J. Vignes (4) created the permutation-perturbation method for evaluating the validity of the solutions of linear algebraic systems, detection of the matrix singularity, and optimal termination criterion of iteratives methods. These problems exist and are considerably amplified in linear and non-linear programming algorithms using near simplex methods : Reduced Gradient of P. Wolfe and Generalized Reduced Gradient of J. Abadie (1) ; effectively, these methods proceed with a long sequence of matrix inversions which increases rounding errors, and it is not unu4sual to obtain false basic solutions or singular basic matrices. Moreover, the classical termination criterions of unconstrained optimization may involve either an untimely stop of the algorithm producing a solution far from the optimum, or, on the contrary, a large number of unprofitable iterations which does not improve the current solution. I suggest, in this paper, some quick and efficient procedures for solving these problems.     

UNIX as a basis for CAD software

The suitability of the UNIX operating system as a basis for constructing and using CAD software is assessed in the light of several years experience of using it for this purpose at EdCAAD.     

Supporting parallel programming in a distributed UNIX environment

A distributed processing system based on UNIX (trademark of Bell Laboratories) is currently operational at New Mexico State University. The system which is composed of a variety of PDP-11 and LSI-11 processing elements allows users to schedule tasks to run totally or in parallel on its satellite units. A UNIX-like kernel is run on the satellite processors and this allows virtually any process to run on any processing element. The architecture of the system is a star configuration with a PDP-11/34a as the central or host node. To support experiments in parallel processing, a parallel version of the C programming language has been developed which allows users to write programs as a collection of functional units which can be automatically scheduled to run on the satellite processors. In this paper the structure of the system is described in terms of hardware and software, and our implementation of pc, a parallel C language, is discussed.     

机器人控制软件的图形化编程系统设计

提出了一种基于图形化编程的机器人软件系统的总体结构设计,包括软件结构的总体设计思路,主要处理从流程图式的图形化结构到类C语言的转换,再将这种类C语言翻译转换为下位机所能识别的目标代码,经过串口通讯下载到下位机中,完成上位机和下位机的信息交互.提出的设计方法和思路已经过严格的测试和检测,实际应用表明,该系统具有较好的灵活性,稳定性和实用性.     

Simulating the DYNIX operating system parallel programming interface on a UNIX system

This paper presents the implementation of multitasking functions of DYNIX Sequent computers on the UNIX operating system. The Sequent computers are shared memory multiprocessor computers running the DYNIX operating system. These functions support data and function partitioning. They let the user implement subprograms by the processors of a Sequent computer in parallel. The functions can synchronize, lock, and unlock data and program segments. As a result, the simulator allows the users to develop their multitasking programs on a uniprocessor computer such as a SUN workstation, and later port them to a Sequent computer. Further, the simulator adds a level of abstraction on top of UNIX for concurrent programming. The functions of the simulator allow the user to handle the communication and synchronization of the processes in a program at a higher level of abstraction, while concentrating on the design of multitasking algorithms. The simulator is applied to a parallel selection algorithm. © 1998 John Wiley & Sons, Ltd.     

The software tools project

A project is described in which the software tools of Kernighan and Plauger1 are implemented on a Burroughs B1700 computer under a non-standard operating system. A command language interpreter similar to that of the UNIX operating system has also been implemented to provide an environment in which the tools may be used. The project was completed by five first-year postgraduate students in the remarkably short time of approximately 12 man-weeks. A translation program for the tools is described, together with some of the associated software required to support them.     

On knowledge-based software tools

In this paper several ideas and examples are presented illustrating possibilities in designing certain knowledge-based software tools, i.e., the software tools with a knowledge base containing necessary and relevant knowledge and human experience, represented in a suitable way.     

UNIX系统安全策略探讨

随着互联网的飞速发展,网络安全逐渐成为一个潜在的巨大问题。网络安全性是一个涉及面很广泛的问题,但先进的技术是网络安全与保密的根本保证。本文以目前网上服务器大多采用的UNIX系统为对象,对它的安全问题进行探讨和研究。     

The impact of tools on software productivity

It is common knowledge that to stay competitive, your software organization must continuously improve product quality and customer satisfaction, as well as lower software development costs and shorten delivery time. The paper considers how software tools are an effective way to improve software development variables such as productivity and product quality. It considers software tool selection and process improvement costs     

Microprocessors and software design tools

Software development aids available to the programmer are introduced. Application programs can be broken down into almost independent software modules. Each module can be independently developed and its interface with other modules defined. Microprocessor development systems, software components and future software are discussed. It seems that changes in computer system architecture are inevitable as LSI technology spreads computing, but this will also lead to better, more reliable software development tools.     

Knowledge intensive software engineering tools

Most software engineering tools use a shallow representation of software objects and manipulate this representation using procedural methods. This approach allows one to get off to a fast start and quickly provides a tool that delivers benefits. However, a point will be reached where more knowledge-intensive approaches will be needed to achieve significantly higher levels of capability. The authors suggest that the software engineering tools of the future will have to rely on: deep representation to capture a sufficiently large part of knowledge about programming in general and particular programs; inspection methods to deal with complexity; and intelligent assistance     

UNIX操作系统安全分析

UNIX操作系统的安全性已经成为受人关注的问题。本文从逻辑安全角度出发,针对普通用户、超级用户和源代码编制者,主要就BSD4 UNIX讨论各种可能的安全违例,并揭示一些现有版本中存在的漏洞。     

Testing tools [software]

After a brief overview, separate presentations are given on tools that support the testing process in a variety of ways. Some tools simulate the final execution environment as a way of expediting test execution, others automate the development of test plans, and still others collect performance data during execution. The tools address three aspects of the testing process. They provide a controlled environment in which testing can take place as well as test-data control, and some tools actually perform the tests, capturing and organizing the resulting output. The tools covered are: RUTE (Real-Time Unix Text Environment); Xray/DX; TDC (Testing and Debugging Concurrent) Ada; T; Mothra; Specification Analyzer; and Test inc     

Logic programming and software maintenance

The main objective of this short paper is to describe the relationship between software maintenance and logic programming (both declarative and procedural), and to show how ideas and methods from logic programming (in particular, methods invented by M. Gelfond) can be used in software maintenance. The material presented in this paper partly appeared in (Luqi and Cooke, 1995). The main difference is that (Luqi and Cooke, 1995) is aimed mainly at software engineers, so it only briefly touches on the software engineering problems, while describing in great detail the basics of logic programming. In contrast, in this paper, we assume that the corresponding logic programming notions are well known, but describe the corresponding software engineering applications in greater detail. This revised version was published online in June 2006 with corrections to the Cover Date.     

UNIX系统中帐户的安全性

本文详细地探讨了UNIX系统中帐户安全性问题及其解决方法。     

Portable tools for Fortran parallel programming

This paper presents a survey of some of the tools, techniques, and constructs for the development of portable, multitasked Fortran programs. The study mainly focuses on existing software tools that implement different approaches to achieving portability of multitasked Fortran programs for local and shared memory multiprocessor computers. However, some proposed approaches are also included. It appears that while each approach enjoys some advantages and suffers some disadvantages, at present, the development and use of portable multitasking tools is in its infancy, and thus no one system is clearly superior. Indeed, we expect that, for the foreseeable future, these and perhaps other techniques will all be actively pursued.