Growth Phenomena — Algebraic and Geometric Descriptions

An enormous variety of nonlinear dynamical systems can be — by suitable introduction of new coordinates — represented in the form of polynomial systems and then can be reduced to Volterra systems, where the nonlinearities are at most quadratic. In this paper, we discuss a link between systems of differential equations with homogeneous quadratic polynomial vector fields and non-associative algebras on the one hand and the question of representation of such systems as geodesics in some Finsler spaces on the other hand.     

The Computer Virus — From There to Here.: An Historical Perspective.

I was sitting at my desk in the Computer Centre of University College, Dublin, checking my E-mail. Suddenly, from the corner of my right eye, I detected an arm swooping down towards my keyboard, like an axe about to fell a tree. This was an arm with a mission. It removed my hand, which was just about to press ‘receive’ on an interesting looking E-mail involving a Christmas tree greeting. Of course, my better-informed colleague knew that this was the Christma Exec virus, and that I would not be doing myself, or anyone else, any favours by accepting and executing it. It was December 1987, and my very first introduction to the computer virus. My love affair with the subject has continued over the past thirteen years (although I do not claim to have a copy of The Little Black Book of Computer Viruses sitting on my bookshelf!), and like myself, the computer virus has evolved into a more complex and sophisticated entity.     

Quest—Two curriculum projects: Perspectives,practice and evidence

Two school-based research projects, in the domain of information handling, have recently been inaugurated within the Chiltern Region of the Microelectronics Education Programme. The broad aim of the Projects is to investigate the application of computer-based information handling in both discrete syllabuses and cross-curriculum activities in Primary schools and within the Humanities in Secondary schools. Particular reference is made to skills-based approaches and inquiry learning within these syllabuses.The Projects intend to describe and illustrate the range and types of activities in which information technology can play an integral part and to identify the skills, techniques and the nature of learning that takes place through computer-based information handling. Teacher development in incorporating computer-based approaches, strategies for in-service education of teachers and the influence of computer-based information handling upon curriculum development are also under investigation. The QUEST family of programs and associated utilities are a central feature of the software employed in the Projects.It is proposed that a “common core” of information skills exists independently of the subject discipline but which relates both subject-specific collection to subject-specific methodology. The adoption of such approaches, however, influences both the environment within which children's learning takes place and the design of curricula to facilitate such learning. Equally, data handling facilities might be seen to influence the respective roles of child and teacher, the balance between discrete and continuous activities within a curriculum and the requirements for INSET in responding to such facilities.     

Differential–Algebraic Equations and Dynamic Systems on Manifolds

The authors consider current problems of the modern theory of dynamic systems on manifolds, which are actively developing. A brief review of such trends in the theory of dynamic systems is given. The results of the algebra of dual numbers, quaternionic algebras, biquaternions (dual quaternions), and their application to the analysis of infinitesimal neighborhoods and infinitesimal deformations of manifolds (schemes) are presented. The theory of differential–algebraic equations over the field of real numbers and their dynamics, as well as elements of trajectory optimization of respective dynamic systems, are outlined. On the basis of connection in bundles, the theory of differential–algebraic equations is extended to algebraic manifolds and schemes over arbitrary fields and schemes, respectively.     

Computer Master——硬件榜样——硬件酷潮

在选购电脑配件时,你是不是有种找不到北的感觉？对五花八门的产品,我们如何选择呢?《DIY选购之十八般精通》将传授你一些基本的选购常识和技巧,要买配件的朋友最好看看哟。这了配合这篇文章,我们还准备了一篇识别假货的文章——《真假一抓准,买卖两不误》,虽然短小但却精干。现在DVD已经相当成熟了,正在迅速向市场普及,你有没有动心呢?