Some new simple Lie algebras in characteristic 2

We describe an algorithm for computing automorphism groups and testing isomorphisms of finite dimensional Lie algebras over finite fields. The algorithm is particularly effective for simple or almost simple Lie algebras. We show how it can be used in a computer search for new low dimensional simple Lie algebras over the field with two elements.     

A review of “DESTINY AND CONTROL IN HUMAN SYSTEMS”, Studies in the Interactive Connectedness of Time (Chronotopology) by Charles Muses. Kluwer-Nijhoff Publishing,Boston-Dordrecht-Lancaster, 1985, 216 pages, $42.00.

Many complex self-organizing systems may not be easily modeled with the help of differential equations. Modern studies in complexity generated new kinds of modeling paradigms such as Cellular Automata (CA), Boolean Networks, and Multiagent Systems. Such models are built from large numbers of interacting units with simple behavior defined in terms of production rules. These models are capable of reproducing unexpected complex organization patterns where the character of the organization could not be derived from the character of the rules defining the behavior of units. Organization that is not evident from the dynamic rules is called emergent . The existence of emergent organization demonstrates the inadequacy of the traditionally accepted association of systems organization with the dynamic equation of the system. The main objective of the paper is to describe new General Systems Theory (GST) framework that gives appropriate account of new dimensions of organization and accommodates new approaches to modeling of complex adaptive systems (CAS). To describe system states and state sequences we use concept model from formal semantics. Dynamics of a system are described with the help of patterns or production rules. The isomorphism of systems is naturally represented as model isomorphism. The organization of a system is a set of formulae with free variables, which have interpretation on the models that represent the system. The framework introduced here is developed as a part of our eco-modeling project. We also discuss the architecture of ecological simulator, LEM (Logic for Eco-Modeling), and its implementation in Visual Prolog that serves as an example of practical application of the framework.     

事件空间与软件设计

1.软件设计中的动态技术提到软件设计中的动态技术,也许每一个软件设计人员都知道一些,也有不少的软件声称其界面是全动态、全开放的。但是,就我们所知,目前还没有一个软件在其所涉及的领域内在界面和其响应的事件上做到完全的开放性和动态性。当前,人们普遍认为的界面的开放性,从严格的意义上讲,只是界面花样的开放性和其响应的事件上的一种预定义动态性。我们可以称这种预定义动态设计为准动态技术,以区别于完全开放的动态技术。准动态技术的一种典型设计方式是下面的动态菜单和动态按钮的设计方式。     

What is a Sorting Function?

What is a sorting function—not a sorting function for a given ordering relation, but a sorting function with nothing given?Formulating four basic properties of sorting algorithms as defining requirements, we arrive at intrinsic notions of sorting and stable sorting: A function is a sorting function if and only it is an intrinsically parametric permutation function. It is a stable sorting function if and only if it is an intrinsically stable permutation function.We show that ordering relations can be represented isomorphically as inequality tests, comparators and stable sorting functions, each with their own intrinsic characterizations, which in turn provide a basis for run-time monitoring of their expected I/O behaviors. The isomorphisms are parametrically polymorphically definable, which shows that it is sufficient to provide any one of the representations since the others are derivable without compromising data abstraction.Finally we point out that stable sorting functions as default representations of ordering relations have the advantage of permitting linear-time sorting algorithms; inequality tests forfeit this possibility.     

Approximate topological matching of quad meshes

In this paper, we study the problem of approximate topological matching for quadrilateral meshes, that is, the problem of finding as large a set as possible of matching portions of two quadrilateral meshes. This study is motivated by applications in graphics that involve the modeling of different shapes that have results needing to be merged in order to produce a final unified representation of an object. We show that the problem of producing a maximum approximate topological match of two quad meshes is NP-hard and that its decision version is NP-complete. Given these results, which make an exact solution extremely unlikely, we show that the natural greedy algorithm derived from polynomial-time graph isomorphism can produce poor results, even when it is possible to find matches with only a few nonmatching quads. Nevertheless, we provide a “lazy-greedy” algorithm that is guaranteed to find good matches when mismatching portions of mesh are localized. Finally, we provide empirical evidence that this approach produces good matches between similar quad meshes.

Symmetries of 2-D Images: Cases without Periodic Translations

The different ways in which images, defined as scalar functions of the Euclidean plane, can be symmetrical is considered. The symmetries analyzed are relative to the class of image isometries, each of which is a combined spatial and intensity isometry. All symmetry types, apart from those with discrete periodic translations, are derived. Fifteen such types are found, including one that has not previously been reported. The novel type occurs when an image has a continuous line of centres of symmetry each like the one found in the Taiji (Yin-Yang) symbol.

徽质空间再创造之思考——以马鞍山洪滨丝画园方案设计为例

徽派建筑文化创新是一个深刻的理论与实践课题,该文以洪滨丝画园为依托,由项目本身的要求与可能性出发,衍生出总体理念,提出关于如何对徽质空间进行再创造的几点思考,以使构思逻辑逐步展开在具体设计中。文章着重从群体布局、单体空间、形式语汇的现代转译等几方面,在同地域传统关系上提出了布局上同构、空间上同质、以及结合主题对传统语汇进行隐性转译等策略。     

Energy production from biogas in the Italian countryside: Policies and organizational models

In recent years, Italy has witnessed a proliferation of agricultural biogas plants. This article argues that institutional factors have played an important role in their diffusion. It describes the state and evolution of agricultural biogas in Italy, and then investigates the extent to which institutional pressures have been influential in shaping organizational models of biogas production. It finds that the dominance of one particular organizational model is the result of an isomorphic process in which a monopolistic market, legal structures, and subsidies play a role. The prevalence of this organizational model, however, does not lead to the effective use of biogas production, and furthermore it results in low environmental efficiency. For a more sustainable development of bioenergy, Italian policy-makers should reform the existing institutional framework by reorganizing subsidies, liberalizing the management of gas grids, and involving farmers in local projects.     

Alternative characterizations for the representation of families of sets by fuzzy sets

We investigate the representation of a given family of sets by a fuzzy set in such a way that the level sets of the fuzzy set are precisely the given sets. This concept of representation is widely used in the literature for the classification and study of fuzzy structures on the same underlying set. Negoita and Ralescu obtained two theorems, both giving necessary and sufficient conditions, one called the representation theorem and the second called the generalized representation theorem. Our aim in this paper is to take a closer look at both theorems, hence establishing some equivalent forms and several constructive remarks, including some directions for future investigations.     

On fuzzy isomorphism theorems of hypermodules

We introduce the concept of normal fuzzy subhypermodules of hypermodules and establish three isomorphism theorems of hypermodules by using normal fuzzy subhypermodules.