Center for Complexity Studies

Bucharest, Romania

Center for Complexity Studies

Bucharest, Romania
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Dan Milici L.,Stefan Cel Mare University of Suceava | Caragea A.,Stefan Cel Mare University of Suceava | Jinaru A.,Center for Complexity Studies | Niculescu G.,Constantin Brâncusi University
Proceedings of the 2016 International Conference and Exposition on Electrical and Power Engineering, EPE 2016 | Year: 2016

In this paper we give a stipulative definition of the term 'situation' (a reductionist representation of the world seen as being psychological (ψ) and physical () drivable) and we apply it for defining the concepts of visiting-situations tracking system (VSTS) and visiting-situations aware system (VSAS). We use these concepts to treat the hypothetical case of a HERMES service (Heritage Enriching through the Rooting Management of Experience Services) and we conceive a simple solution for designing a VSTS capable to generate the essential data for identifying the objects of a visited site and, at the same time, the attention behavior of a user-visitor regarding the respective objects. © 2016 IEEE.

Mayo M.,University of Missouri | Mayo M.,U.S. Army | Gheorghiu S.,Center for Complexity Studies | Pfeifer P.,University of Missouri
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2012

A renormalization approach is used to derive an analytic formula for the total current crossing the reactive surface of a Cayley tree of cylindrical tubes under a Helmholtz-type approximation to the full diffusion-reaction problem. We provide analytic conditions for the emergence of a plateau in the current-a region of maximum insensitivity of the current to variations in either the reaction rate (membrane permeability) or the diffusivity. The occurrence of such a plateau is associated with a partial screening regime wherein most of the active surface is screened to incoming diffusing particles. Large trees trade efficiency for fault tolerance, a valuable feature which may provide robustness to mammalian respiratory systems and tolerance to catalytic poisoning in chemical reactors. © 2012 American Physical Society.

Van Ommen J.R.,Technical University of Delft | Sasic S.,Chalmers University of Technology | Van der Schaaf J.,TU Eindhoven | Gheorghiu S.,Center for Complexity Studies | And 2 more authors.
International Journal of Multiphase Flow | Year: 2011

This work reviews methods for time-series analysis for characterization of the dynamics of gas-solid fluidized beds from in-bed pressure measurements for different fluidization regimes. The paper covers analysis in time domain, frequency domain, and in state space. It is a follow-up and an update of a similar review paper written a decade ago. We use the same pressure time-series as used by Johnsson et al. (2000). The paper updates the previous review and includes additional methods for time-series analysis, which have been proposed to investigate dynamics of gas-solid fluidized beds. Results and underlying assumptions of the methods are discussed. Analysis in the time domain is often the simplest approach. The standard deviation of pressure fluctuations is widely used to identify regimes in fluidized beds, but its disadvantage is that it is an indirect measure of the dynamics of the flow. The so-called average cycle time provides information about the relevant time scales of the system, making it an easy-to-calculate alternative to frequency analysis. Autoregressive methods can be used to show an analogy between a fluidized bed and a single or a set of simple mechanical systems acting in parallel. The most common frequency domain method is the power spectrum. We show that - as an alternative to the often used non-parametric methods to estimate the power spectrum - parametric methods can be useful. To capture transient effects on a longer time scale (>1. s), either the transient power spectral density or wavelet analysis can be applied. For the state space analysis, the information given by the Kolmogorov entropy is equivalent to that of the average frequency, obtained in the frequency domain. However, an advantage of certain state space methods, such as attractor comparison, is that they are more sensitive to small changes than frequency domain methods; this feature can be used for, e.g., on-line monitoring. In general, we conclude that, over the past decade, progress has been made in understanding fluidized-bed dynamics by extracting the relevant information from pressure fluctuation data, but the picture is still incomplete. © 2010 Elsevier Ltd.

Hou C.,Yeshiva University | Gheorghiu S.,Center for Complexity Studies | Huxley V.H.,University of Missouri | Pfeifer P.,University of Missouri
PLoS Computational Biology | Year: 2010

The space-filling fractal network in the human lung creates a remarkable distribution system for gas exchange. Landmark studies have illuminated how the fractal network guarantees minimum energy dissipation, slows air down with minimum hardware, maximizes the gas- exchange surface area, and creates respiratory flexibility between rest and exercise. In this paper, we investigate how the fractal architecture affects oxygen transport and exchange under varying physiological conditions, with respect to performance metrics not previously studied. We present a renormalization treatment of the diffusion-reaction equation which describes how oxygen concentrations drop in the airways as oxygen crosses the alveolar membrane system. The treatment predicts oxygen currents across the lung at different levels of exercise which agree with measured values within a few percent. The results exhibit wide-ranging adaptation to changing process parameters, including maximum oxygen uptake rate at minimum alveolar membrane permeability, the ability to rapidly switch from a low oxygen uptake rate at rest to high rates at exercise, and the ability to maintain a constant oxygen uptake rate in the event of a change in permeability or surface area. We show that alternative, less than space-filling architectures perform sub-optimally and that optimal performance of the space-filling architecture results from a competition between underexploration and overexploration of the surface by oxygen molecules. © 2010 Hou et al.

Andreescu C.,Center for Complexity Studies
European Journal of Science and Theology | Year: 2013

The starting concepts of the paper are complexity, irreducibility and representation of information integration by closure spaces. It is marked out that closure spaces are the generalization of the concept of limits of sequences. This very old idea is extremely rich in deep significances and by comparison to the definition of real numbers starting from the rational ones, one sees that the limit is in fact the sequence itself. Accepting a number to be equivalent to a class of infinite sets of other numbers means jumping from one level of abstraction to a higher one, it means gaining a supplementary dimension of abstraction. This means a way to obtain a multitude of levels of abstraction. Although this situation is quite different of the levels of reality, this situation is compared to the concept of levels of reality of Basarab Nicolescu and to the Goedelian structure generated by the concept 'included tertium' of Stephane Lupasco. Beyond this construction of discursive logic lies the idea of 'hidden tertium', the hidden significance that cannot be comprised by words, theories or any logical system. A personal interpretation of those concepts is made in occurrence to the digression about hierarchical functional systems and the intrinsic significance. This is about the significance 'attached' to each object on any level of reality, no matter how deep or high this level would be and which is inseparable of the object itself. The interpretation leads to comparisons to concepts of other two Romanian philosophers Mihai Draganescu and Paul Constantinescu.

Andreescu C.,Center for Complexity Studies | Andreescu L.,Center for Complexity Studies
European Journal of Science and Theology | Year: 2014

Digital Technologies are more and more present at any level in society and thus influencing our lives and our attitudes towards everything we are involved in. Although we might say that the capabilities of modern computational systems could 'weaken' our spirit because of the implied comfort, this is not true, as a great deal of results of some computational capabilities can represent a challenge to the human spirit. As an example, data mining and pattern recognition software could lead to a complete remodelling of the conceptual framework for physical systems, measurements and physical quantities and set new bases to the way relations between them are interpreted. In this way, emergent phenomena occurring at global levels which cannot yet be estimated will become explorable. The paper will show some of the perspectives of this new 'look into' physical systems. But the spiritual approach is seen to be needed in education. The overwhelming emergence of digital gadgets and apps are changing the relation between the educating and educated person, as children and teenagers are eager and much more capable to assimilate the novelties of the digital era. They begin to 'feel their superiority' over their educators and what they really feel (unfortunately only at an unconscious level) is the urge for radical changes in the present life of mankind. As one can easily see that traditional education is a continuation of the standard attitudes of primitive societies, with unquestioned authority of the parents over the children, the urge for radical changes comes from the need of another spiritual attitude towards the partnership educator/educated. The paper marks out the importance of real communication, based on face-to-face transmission of non verbal messages in both directions. On the other hand the social impact of the internet has not to be lost out of view while looking for communication in an educational partnership. Educators have to understand how to use social networks to improve essential messages exchange with the educated.

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