Technical Reports: 2005-08

Technical Reports: 2004

Technical Reports: 2003

Technical Reports: 2002

Technical Reports: 2001

Technical Reports: 2000

Technical Reports: 1995-99

Technical Reports: 1990-94

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Technical Reports: 2005-08

Technical Reports: 2004

Technical Reports: 2003

Technical Reports: 2002

Technical Reports: 2001

Technical Reports: 2000

Technical Reports: 1995-99

Technical Reports: 1990-94

Technical Reports: 1988-89

CCSR Home Page

CCSR Technical Reports,
with Abstracts: 2000-04




    Technical Reports, with Abstracts: 2004

  1. D. Farrell, A. Hübler, J. Brewer, I. Hübler, Acceleration Beyond the Wave Speed in Dissipative Wave-Particle Systems , Technical Report CCSR-04-1

    Abtract: The limiting speed of isotropic particles accelerated by waves is the wave speed. We study the acceleration of anisotropic objects in classical wave-particle systems. We find that anisotropic objects can be trapped by the waves and reach a limiting speed that is larger than the wave speed. We investigate the impact of anisotropies in the dissipation mechanism and in the mass distribution. We discuss particle accelerator applications. Preprint




    2. Technical Reports, with Abstracts: 2003

  2. J. Xu, A. Hübler, Enhanced Diffraction Pattern from a Fibonacci Chain , Technical Report CCSR-03-1

    Abtract: We study the diffraction patterns of a one-dimensional Fibonnaci chain from quasiperiodic pulse trains. We find a single prominent peak when the dynamics of the incident wave matches the arrangement of the scatterers, that is, when the pulse train and the scatterers are in resonance. The maximum diffraction angle and the resonant pulse train determine the position of the scatterers. These results may provide a methodology for the quality control of Fibonnaci multilayers, and may have further impact when extended to higher dimensions. Reprint

  3. G. Foster, A. Hübler, Robust and Efficient Interaction with Complex Systems , Technical Report CCSR-03-2

    Abtract: Low-dimensional chaotic map dynamics has been successfully used to predict the dynamics of high-dimensional systems far from equilibrium. For control, low-dimensional models can be used only if the the control force is very small, otherwise hidden degrees of freedom may become excited. We study the control of chaotic map dynamics with extremely small forcing functions.. We find that the smallest forcing function, which is called a resonant forcing function, echoes the natural dynamics of the system. This means, when the natural dynamics of the system is irregular, the optimal forcing function is irregular too. If the natural dynamics contains a certain periodicity, the optimal forcing function contains that periodicity too. We show that such controls are effective even if the system has hidden degrees of freedom and if the probes of the control system have a low resolution. Further we show that resonant forcing functions of chaotic systems decrease exponentially, where the rate equals the Liapunov exponent of the unperturbed system. We apply resonant forcing functions for efficient control of chaotic systems and for system identification. Preprint

  4. D. Smyth, A. Hübler, A Conductivity-Dependent Phase Transition from Closed-Loop to Open-Loop Dendritic Networks , Technical Report CCSR-03-3

    Abtract: Motivated by a principle of minimum dissipation per channel length, we introduce a model for branching, hierarchical networks in an open, dissipative system. Global properties of the resulting structures are observed to scale with a ratio of conductivity in the dendrite material to conductivity in the lattice material. Beyond a critical conductivity ratio, the resulting structures are naturally self-avoiding and possess scale-independent branching ratios. Our findings suggest that the conductivity ratio determines the geometric properties of naturally-arising dendritic structures. We discuss empirical verification in the context of a system of self-organizing agglomerates of metal particles on castor oil. Preprint

  5. P. Melby, N. Weber, A. Hübler, Dynamics of Self-Adjusting System with Noise , Technical Report CCSR-03-4

    Abtract: We perform studies of several self-adjusting systems with noise. In our analytical and numerical studies, we find that the dynamics of the self-adjusting parameter can be accurately described with a rescaled diffusion equation. We find that adaptation to the edge of chaos, a feature previously ascribed to self-adjusting systems, is only a long-lived transient when noise is present in the system. In addition, using analytical, numerical, and experimental studies, we find that noise can cause chaotic outbreaks where the parameter reenters the chaotic regime and the system dynamics become chaotic. We find that these chaotic outbreaks have a power law distribution in length. Preprint

  6. A. Barr, A. Hübler, Adaptation to the Edge of Chaos in a Non-Isothermal Autocatalator , Technical Report CCSR-03-5

    Abtract: Numerical simulations of a low-pass filtered feedback from a dynamical variable to the system parameter of a non-isothermal autocatalator are examined. Parameter values for which the limiting dynamics is chaotic are found to evolve to nearby values yielding periodic dynamics while parameter values yielding periodic dynamics are uneffected. The system thus exhibits adaptation to the edge of chaos. This suggests that low-pass filters, believed to be quite common in chemical reactions, may be one reason few chaotic reactions have been observed experimentally. Preprint




    7. Technical Reports, with Abstracts: 2002

  7. P. Melby, N. Weber, A. Hübler, Robustness of Adaptation in Controlled Self-Adjusting Chaotic Systems , Technical Report CCSR-02-1

    Abtract: It was recently shown that self-adjusting systems adapt to the edge of chaos. We study the robustness of that adaptation with respect to a controlling force. We first use numerical simulations on a modified logistic map. With those, we find that, if the controlling force has a target value of the parameter that leads to periodic dynamics, the control is successful, even for very small controlling forces. We also find, however, that if the target value for the parameter leads to chaotic dynamics, the parameter resists the control and adaptation to the edge of chaos is still observed. When the controlling force is very strong, adaptation to the edge of chaos is weaker, but still present in the system. We also perform experiments with a self-adjusting Chua circuit and find the same behavior. We quantify these results with a measurement of the controlling force. The control used can be expressed either as a parametric control or as an additive, closed-loop control. Reprint




    8. Technical Reports, with Abstracts: 2001

  8. L. Durak, A. Hübler, Scaling of Knowledge in Random Conceptual Networks , Technical Report CCSR-01-1

    Abtract: We use a weighted count of number of nodes and relations in a conceptual network as a measure for knowledge. We study how a limited knowledge of the prerequisite concepts affects the knowledge of a discipline. We find that the practical knowledge and expert knowledge scale with the knowledge of prerequisite concepts, and increase hyperexponentially with the knowledge of the discipline specific concepts. We investigate the maximum achievable level of abstraction as a function of the material covered in a text. We discuss possible applications for student assessment. Reprint




    9. Technical Reports, with Abstracts: 2000

  9. P. Melby, J. Kaidel, N. Weber, A. Hübler, Adaptation to the Edge of Chaos in the Self-Adjusting Logistic Map , Technical Report CCSR-00-1

    Abtract: Self-adjusting, or adaptive, systems have gathered much recent interest. We present a model for self-adjusting systems which treats the control parameters of the system as slowly varying, rather than constant. The dynamics of these parameters is governed by a low-pass filtered feedback from the dynamical variables of the system. We apply this model to the logistic map and examine the behavior of the control parameter. We find that the parameter leaves the chaotic regime. We observe a high probability of finding the parameter at the boundary between periodicity and chaos. We therefore find that this system exhibits adaptation to the edge of chaos. Reprint