Search results for "Systems Theory"

Flexibility of TTF. a theoretical study

1999

Abstract The folding of tetrathiafulvalene along the S···S axes has been investigated using highly-accurate quantum-chemical calculations. A very flat, two-fold potential is found for neutral TTF where minima correspond to boat conformations (θ ≈ 15–20 °). The flatness of the folding potential indicates that TTF is conformationally more flexible than usually thought.

Diffusive energy growth in classical and quantum driven oscillators

1991

We study the long-time stability of oscillators driven by time-dependent forces originating from dynamical systems with varying degrees of randomness. The asymptotic energy growth is related to ergodic properties of the dynamical system: when the autocorrelation of the force decays sufficiently fast one typically obtains linear diffusive growth of the energy. For a system with good mixing properties we obtain a stronger result in the form of a central limit theorem. If the autocorrelation decays slowly or does not decay, the behavior can depend on subtle properties of the particular model. We study this dependence in detail for a family of quasiperiodic forces. The solution involves the ana…

Perspectives on aerosol deposition to natural surfaces: interactions between aerosol residence times, removal processes, the biosphere and global env…

1990

Abstract This paper summarizes the state-of-the-art and the research needs in the areas of aerosol residence-time assessments, deposition modelling, and understanding of aerosols in biogeochemistry. Research needs are emphasized from a systems perspective of global environmental change. Although fundamental quantitative knowledge is lacking, some qualitative linkages between source strengths, residence times, removal processes and the biosphere can be identified. It turns out that not only are the respective areas as such challenged by new problems, superimposed on the fairly well established conventional ones, but these areas also face mutually operating sets of feedbacks between residence…

FOUNDATIONS OF FRACTIONAL DYNAMICS

1995

Time flow in dynamical systems is reconsidered in the ultralong time limit. The ultralong time limit is a limit in which a discretized time flow is iterated infinitely often and the discretization time step is infinite. The new limit is used to study induced flows in ergodic theory, in particular for subsets of measure zero. Induced flows on subsets of measure zero require an infinite renormalization of time in the ultralong time limit. It is found that induced flows are given generically by stable convolution semigroups and not by the conventional translation groups. This could give new insight into the origin of macroscopic irreversibility. Moreover, the induced semigroups are generated …

Structural and dynamic complexities of risk and catastrophe systems : an approach by system dynamics modelling

2006

Cette publication figure en ligne à l'adresse suivante : http://www-lih.univ-lehavre.fr/~bertelle/cossombook/complex22.pdf; International audience; Risk and catastrophe are complex systems. Within thescope of this paper, we focus our attention on structuraland dynamic complexities of catastrophes and on thepossibility of modelling and simulating its doublecomplexity with a formal and methodological framework:the General Systems Theory and System Dynamicsmodelling. We then briefly propose a model of urbancatastrophe related to a flood. We then propose some waysof research allowing exceeding the limits related to themodelling.

SYSTEMS DECOMPOSITION AND COUPLING

1993

In order to handle efficiently complex models of real systems, it is a convenient practice to decompose them into subsystems that are validated independently. The next step would be joining the subsystems into a global system and performing a new global validation. A formalization of this process is performed as a consequence of practical experience with a model generator expert system based on general systems theory.

Towards the theory of M-approximate systems: Fundamentals and examples

2010

The concept of an M-approximate system is introduced. Basic properties of the category of M-approximate systems and in a natural way defined morphisms between them are studied. It is shown that categories related to fuzzy topology as well as categories related to rough sets can be described as special subcategories of the category of M-approximate systems.

Conceptual History as Political Theory

2000

From causal thinking to wisdom and spirituality: some perspectives on a growing research field in adult (cognitive) development

2015

This article concentrates on the latest international trends in the research on psychological development of adults, and especially on the development of cognition. The field of research has been very fragmented, and researchers have kept creating new models one after another to describe their own lines of thought and also seeking for empirical evidence for their models. This has created a rather equivocal picture of the phenomenon itself. The present article attempts to identify the historical roots of the field, and introduces descriptive factors that could conceptually determine the gist of the phenomenon. In this context we will discuss, mainly, research going back to Piaget and Perry, …

Iterated function systems and well-posedness

2009

Abstract Fractals and multivalued fractals play an important role in biology, quantum mechanics, computer graphics, dynamical systems, astronomy and astrophysics, geophysics, etc. Especially, there are important consequences of the iterated function (or multifunction) systems in several topics of applied sciences [see for example: El Naschie MS. Iterated function systems and the two-slit experiment of quantum mechanics. Chaos, Solitons & Fractals 1994;4:1965–8; Iovane G. Cantorian spacetime and Hilbert space: Part I-Foundations. Chaos, Solitons & Fractals 2006;28:857–78; Iovane G. Cantorian space-time and Hilbert space: Part II-Relevant consequences. Chaos, Solitons & Fractals 2006;29:1–22;…