Towards a Hamilton-Jacobi Theory for Nonholonomic Mechanical Systems

In this paper we obtain a Hamilton-Jacobi theory for nonholonomic mechanical systems. The results are applied to a large class of nonholonomic mechanical systems, the so-called \v{C}aplygin systems.Comment: 13 pages, added references, fixed typos, comparison with previous approaches and some explanations added. To appear in J. Phys.

Hybrid Simulation of Solar-Wind-Like Turbulence

We present 2.5D hybrid simulations of the spectral and thermodynamic evolution of an initial state of magnetic field and plasma variables that in many ways represents solar wind fluctuations. In accordance with Helios near-Sun high-speed stream observations, we start with Alfvnic fluctuations along a mean magnetic field in which the fluctuations in the magnitude of the magnetic field are minimized. Since fluctuations in the radial flow speed are the dominant free energy in the observed fluctuations, we include a field-aligned v(k) with an k(exp 1) spectrum of velocity fluctuations to drive the turbulent evolution. The flow rapidly distorts the Alfvnic fluctuations, yielding spectra (determined by spacecraft-like cuts) transverse to the field that become comparable to the k fluctuations, as in spacecraft observations. The initial near constancy of the magnetic field is lost during the evolution; we show this also takes place observationally. We find some evolution in the anisotropy of the thermal fluctuations, consistent with expectations based on Helios data. We present 2D spectra of the fluctuations, showing the evolution of the power spectrum and cross-helicity. Despite simplifying assumptions, many aspects of simulations and observations agree. The greatly faster evolution in the simulations is at least in part due to the small scales being simulated, but also to the non-equilibrium initial conditions and the relatively low overall Alfvnicity of the initial fluctuations

THE NEXUS BETWEEN KNOWLEDGE MANAGEMENT AND INNOVATION. A LITERATURE REVIEW

Knowledge management is the new managerial discipline whose aim is to support the processes of knowledge exploitation, memorization, re-use and learning. Therefore, it can be said that knowledge management has, implicitly or explicitly, a strong relationship with innovation management. Despite this fact, knowledge management and innovation management have developed into two separate fields and two distinct contexts of research. Starting from these assumptions, the purpose of this paper is to examine how the connection between knowledge management (KM) and innovation management has been developed in the last 10 years. In order to achieve our goal, an etic approach is employed which encompasses an external view of meaning associations and real-world events. The research combines the qualitative with the quantitative perspective and the whole multi-stage process is dominated by an inductive approach. The analysis focuses on 894 articles that were published in knowledge management and innovation journals, mostly indexed in Scopus and Thomson Reuters databases, during 2006 - 2016. The main results prove that there is a strong connection between KM and innovation management although the number of KM journals that approach topics related to innovation is higher than the number of innovation journals that focus on knowledge-related issues. The concept of "innovation" is by far the most used in the analyzed KM papers, while the term of "knowledge" is frequently used as a generic keyword in the Innovation papers; only a few papers are about a specific topic such as product development, project management, and process improvement - in the case of KM journals - or organizational learning, social capital, and human capital - in the case of Innovation journals. The research findings have both theoretical and practical implications. On the one hand, it synthesizes how the link between knowledge management and innovation management evolved in the last 10 years. On the other hand, it may serve as a handbook of managerial guidelines; it brings forward the knowledge management approaches and tools which can be used for product or process innovations

Time-Evolution of the Power Spectrum of the Black Hole X-ray Nova XTE J1550-564

We have studied the time evolution of the power spectrum of XTE J1550-564, using X-ray luminosity time series data obtained by the Rossi X-Ray Timing Explorer satellite. A number of important practical fundamental issues arise in the analysis of these data, including dealing with time-tagged event data, removal of noise from a highly non-stationary signal, and comparison of different time-frequency distributions. We present two new methods to understand the time frequency variations, and compare them to the dynamic power spectrum of Homan et al. All of the approaches provide evidence that the QPO frequency varies in a systematic way during the time evolution of the signal.Comment: 4 pages, 3 figures; 2001 IEEE - EURASIP Workshop on Nonlinear Signal and Image Processing (June 3-6, 2001), and to appear in the proceeding

Discrete variational integrators and optimal control theory

A geometric derivation of numerical integrators for optimal control problems is proposed. It is based in the classical technique of generating functions adapted to the special features of optimal control problems.Comment: 17 page