Linguistic style checking with program checking tools

Written text is an important component in the process of knowledge acquisition and communication. Poorly written text fails to deliver clear ideas to the reader no matter how revolutionary and ground-breaking these ideas are. Providing text with good writing style is essential to transfer ideas smoothly. While we have sophisticated tools to check for stylistic problems in program code, we do not apply the same techniques for written text. In this paper we present TextLint, a rule-based tool to check for common style errors in natural language. TextLint provides a structural model of written text and an extensible rule-based checking mechanism.     

The elliptic curve cryptosystem: A synopsis

There are three types of public key cryptographic systems that are currently considered both secure and efficient. These cryptographic systems, classified according to the mathematical problems upon which they are based, are: the Integer Factorization Systems (of which the RSA algorithm is the most well known example), the Discrete Logarithm Systems (such as the US Government's Digital Signature Algorithm), and the Elliptic Curve Cryptosystem (ECC).¹ Although much has been written about the RSA algorithm and the Digital Signature Algorithm (DSA), little about the ECC appears in the literature written for information systems security practitioners. This is perhaps because the ECC, since its introduction in 1985, has been a subject of interest to more mathematicians than security professionals.     

Software model checking is a rich research field

This introductory paper has been written for readers who know nothing about model checking but do know about software. Its aim is to present, almost without mathematical terms, the fundamental general approaches on which the papers in this Special Section build, and give an idea of what kind of contribution each paper makes. The main issues discussed are motivation for model checking, state spaces, and bounded model checking with sat solvers. Individual papers lead to discuss the following ideas: exploiting a distributed computing environment for model checking, constructing those states first that look most promising for eventually finding errors, only constructing a representative subset of states, the representation of contents of variables in an abstract way with approximation from below, and the use of more general solvers than sat solvers in bounded model checking.     

高速网络安全监控系统的设计与实现

随着计算机网络的发展,对高速网络的安全进行监控变得越来越重詈。结合实际需求,本文提出了一些重要的设计思想,实现与测试了一个基于高速网络关键点捕获,对网络攻击进行实时检测、预警和响应的高速网络安全监控系统原型,有效地解决了目前高速网络安全监控系统存在的一些难题。目前,该系统原型已经在实际中得到成功应用。     

Programming aids for the teaching of programming

This paper describes a system of library segments which have been written to help in the teaching of programming to undergraduates at Nottingham. Each segment contains input for a number of problems in a very specific area of programming, together with checks that the student has solved the problems satisfactorily. The system is implemented in Algol 68-R.     

The new programming discipline

Recently there has been substantial interest in promoting ‘Structured Programming’ as a means of writing more nearly error free programs. However since the chief advocates of structured programming use ALGOL or PASCAL, and disdain FORTRAN, there is a difficulty in communication. Since it is my perception that structured programming and the lessons to be learned from proofs of correctness can be applied in any language, including FORTRAN, I feel that these ideas should be promulgated to applied scientific programmers. Hence this paper will commence with a summary of the whole complex of ideas and practices that are subsumed under the term ‘Structured Programming’. Then some simple examples of top down design and programming will be given. Finally I will return to a discussion of some of the problems which are likely to be encountered in the use and promulgation of structured programming.     

Web Services安全性及其应用的研究

Web Service现在越来越受到IT业和企业的关注。它是一种分布式体系结构，被设计和指定用来促进跨平台的程序对程序通信。这不仅从理念上改变了企业，而且拓宽了企业的营销渠道，为企业的发展带了新的模式。然而同时，由于Web Service的开放性带来了诸多安全性问题。文中将针对Web服务的特点提出相关的安全保障机制并给出相应的技术解决方案。     

An approach to object identification, selection and specification in object-oriented analysis

When using current object-oriented methods in the development of computer-based information systems, problems frequently arise in the identification and specification of 'objects'. In this paper, these problems are discussed and an approach that draws upon interpretivist systems thinking is presented that, it is argued, may alleviate some of the problems. It is proposed that a method that has been developed specifically to aid the user and analyst to appreciate a perceived problem situation might provide a useful aid in the process of identifying objects from the situation which are meaningful to the user. [An attempt has been made to use terminology that is consistent with that used in object-oriented analysis. However, at times this terminology may be at variance with some of the interpretivist ideas put forward (e.g. the term 'user' is adopted, although the authors argue that the notion of 'client' is more appropriate to emphasize the increased involvement and responsibility of the 'user' in the approach advocated)]. The ability to achieve this is expected to facilitate the appropriate mapping of these meaningful objects into a technical specification through object-oriented methods and to encourage user acceptance of the resulting computer-based information system.     

A notation for deterministic cooperating processes

This paper proposes extensions of sequential programming languages for parallel programming that have the following features: 1) Dynamic Structures: The process structure is dynamic. Processes and variables can be created and deleted. 2) Paradigm Integration: The programming notation supports shared memory and message passing models. 3) Determinism: Demonstrating that a program is deterministic-all executions with the same input produce the same output-is straightforward, Programs can be written so that compilers can verify that the programs are deterministic. Nondeterministic constructs can be introduced in a sequence of refinement steps to obtain greater efficiency if required. The ideas have been incorporated in an extension of Fortran, but the underlying sequential imperative language is not central to the ideas described here. A compiler for the Fortran extension, called Fortran M, is available by anonymous ftp From Argonne National Laboratory. Fortran M has been used for a variety of parallel applications     

Applying Structured Programming to Command, Control, and Communication Software Development

Much has been written describing structured programming (SP) technologies, but little has been written concerning measurable results from using those technologies to deliver programs within cost, time, and performance constraints. SP technologies have been applied to large-scale real-time program development, analyzed, and further developed at Hughes since 1971. As new software projects are started, the respective managers must state which of the technologies will and will not be used. The use of the applied techniques is then monitored to determine benefits and problems and to define useful modifications to the technologies.     

Parameterized Polyhedra and Their Vertices

Algorithms specified for parametrically sized problems are more general purpose and more reusable than algorithms for fixed sized problems. For this reason, there is a need for representing and symbolically analyzing linearly parameterized algorithms. An important class of parallel algorithms can be described as systems of parameterized affine recurrence equations (PARE). In this representation, linearly parameterized polyhedra are used to describe the domains of variables. This paper describes an algorithm which computes the set of parameterized vertices of a polyhedron, given its representation as a system of parameterized inequalities. This provides an important tool for the symbolic analysis of the parameterized domains used to define variables and computation domains in PAREs. A library of operations on parameterized polyhedra based on the Polyhedral Library has been written in C and is freely distributed.     

An operating system for interactive terminals

Conventional operating systems have for many-years used the ideas of standard stream interfaces to peripherals. Multi-tasking has been used in order to give an efficient response while maintaining simplicity and flexibility for the user. This paper describes an extension to an operating system which makes similar facilities available for the control of interactive workstations, and also provides a command dispatcher which enables the straightforward implementation of arbitrary user-defined command languages. The current system has been written in BCPL to run on a PDP 11/45 handling a Vector General display, but the design is suitable for use with a variety of terminals, computers and languages.     

Applying human and system reliability analysis to the design and analysis of written procedures in high-risk industries

The importance and prevalence of written work procedures in industries, especially high-risk industries, has resulted in a renewed interest in the design of these procedures. Most of the concern has focused on the formatting, organization, and readability of the procedures. Although these are important issues, it is also important that advantage be taken of the richness in detail and knowledge contained in many of these procedures. Without an understanding of the relationship between the work context, which is largely reflected in written procedures, and behavioral tendencies, a fundamental problem related to the design of written procedures remains unresolved. Specifically, this problem concerns how written procedures can contribute to human error, procedural violations, and ultimately adverse system outcomes. In this article, a contextual modeling perspective to human and system reliability analysis is presented. The application of this approach directly to the process of designing and analyzing written procedures is discussed. In particular, this article discusses how applying this perspective can benefit designers and writers of procedures by increasing their ability to anticipate how written procedures could contribute to human error and adverse outcomes. Examples illustrating these ideas are presented throughout. © 1998 John Wiley & Sons, Inc.     

Improved form of the conjugate gradient method

The conjugate gradient method, which is used for solving systems of linear algebraic equations, is studied. A notation for the method has been found, which proved to be the simplest and the most resistant to rounding errors. A criterion is constructed for the end of iterations based on the prevalence of rounding errors. Numerical calculations are made illustrating the specifics of the method convergence for well- and ill-posed problems. The generalization of this form is written for problems with preconditioning.     

Time Complexity of Evolutionary Algorithms for Combinatorial Optimization： A Decade of Results

Computational time complexity analyzes of evolutionary algorithms (EAs) have been performed since the mid-nineties. The first results were related to very simple algorithms,such as the (1 1)-EA,on toy problems.These efforts produced a deeper understanding of how EAs perform on different kinds of fitness landscapes and general mathematical tools that may be extended to the analysis of more complicated EAs on more realistic problems.In fact,in recent years,it has been possible to analyze the (1 1)-EA on combinatorial optimization problems with practical applications and more realistic population-baeed EAs on structured toy problems. This paper presents a survey of the results obtained in the last decade along these two research lines.The most common mathematical techniques are introduced,the basic ideas behind them are discussed and their elective applications are highlighted.Solved problems that were still open are enumerated as are those still awaiting for a solution.New questions and problems arisen in the meantime are also considered.     

General programmes for least pth and near minimax approximation

User-oriented computer programmes in FORTRAN IV for discrete least pth approximation with a single specified function, and more generalized discrete least pth approximation with various specifications, which may also be used for non-linear programming, are presented. Values of p up to 10" can be used successfully in conjunction with efficient gradient minimization algorithms such as the Fletcher-Powell method and a method due to Fletcher. It has been demonstrated how efficiently extremely near minimax results can be achieved on a discrete sot of sample points using this approach and the programmes written verify this. The programmes may be applied to a wide variety of design problems with a wide range of specifications. They are suitable for electrical network and system design and such problems as filter design.     

Comparing CONCEPT and FLOWTRAN using a process simulator evaluator

A test flowsheets has been written to the specifications evolced by a group of engineers with academic and industrial backgrounds. Incorporated into it are features which are known to give problems in simulations. The test flowsheet was evaluated by carrying out a comparison of CONCEPT and FLOWTRAN. It was demonstrated that the test could be used to identify strengths and weaknesses, major and minor. The study revealed a serious weakness in both systems.     

An automated method for the preparation of orthogonal arrays for use in Taguchi designed experiments

In the last several years, the use of designed experiments in manufacturing and engineering design environments has become increasingly popular through the introduction of the ideas of Dr. G. Taguchi. The Taguchi Method, a systematic technique for experimental design and analysis, employs team oriented solutions to analyze design and production problems and their causes. The Taguchi Method as provided a simplified approach to the design of statistically significant experiments. This has greatly increased the number of experimental design practitioners.

This paper presents a computer program that addresses the need for an automated system able to design the experimental matrices for the orthogonal arrays that are required by Taguchi's Method. The program was written tode sign simple arrays as well as complex multi-level arrays with two-way interactions.     

A new algorithm for the on-line multi-level control of large interconnected systems with fast dynamics

A now two-level algorithm is developed for the on-line optimal control of largo interconnected systems with fast dynamics. On the first level, independent optimization problems are solved for given ’ desired ’ output trajectories which are supplied by the second level. On the second level these ’ desired ’ output trajectories are iteratively improved. For ‘ Linear Quadratic ’ problems, the algorithm has a particularly simple form and for such systems a general purpose computer programme has been written for its implementation. A simple simulation study illustrates the approach.