Patent data as a tool to monitor S & T portfolio's.

This article deals with the use of patent data to monitor science and technology (S&T) portfolios. S&T portfolios have become central tools to examine and to monitor the vitality of both institutions and regions in the innovation game that underpins their economic growth and development. Those portfolios have to be monitored not only at the intra-organizational level, but also at the inter-organizational level and at the levels of specific systems of innovation. Therefore, the development of appropriate, easy-to-use and transparent, benchmark indicators to assess the strengths and weaknesses of organizational S&T portfolios is tantamount. In this paper, we report the construction of such a benchmark indicator and we assess its usefulness by applying it to the European Patent Database.Data; Science; Regions; Systems;

Linking science to technology: using bibliographic references in patents to build linkage schemes.

In this paper, we develop and discuss a method to design a linkage scheme that links the systems of science and technology through the use of patent citation data. After conceptually embedding the linkage scheme in the current literature on science-technology interactions and associations, the methodology and algorithms used to decelop the linkage scheme are discussed in detail. The method is subsequently tested on and applied to subsets of USPTO patents. The results point to highly skewed citation distributions, enabling us to discern between those fields of technology that are highly science-interactive and those fields where technology develoment is highly independent from the scientific literature base.Science; Patents; Systems; Data; Algorithms; Distribution;

On the effectiveness of mixing in violent relaxation

Relaxation processes in collisionless dynamics lead to peculiar behavior in systems with long-range interactions such as self-gravitating systems, non-neutral plasmas and wave-particle systems. These systems, adequately described by the Vlasov equation, present quasi-stationary states (QSS), i.e. long lasting intermediate stages of the dynamics that occur after a short significant evolution called "violent relaxation". The nature of the relaxation, in the absence of collisions, is not yet fully understood. We demonstrate in this article the occurrence of stretching and folding behavior in numerical simulations of the Vlasov equation, providing a plausible relaxation mechanism that brings the system from its initial condition into the QSS regime. Area-preserving discrete-time maps with a mean-field coupling term are found to display a similar behaviour in phase space as the Vlasov system.Comment: 10 pages, 11 figure

Trends in the inter-regional and international research collaboration of the PRC’s regions: 2000-2015

Merit, Expertise and Measuremen

Quasi-equilibria in one-dimensional self-gravitating many body systems

The microscopic dynamics of one-dimensional self-gravitating many-body systems is studied. We examine two courses of the evolution which has the isothermal and stationary water-bag distribution as initial conditions. We investigate the evolution of the systems toward thermal equilibrium. It is found that when the number of degrees of freedom of the system is increased, the water-bag distribution becomes a quasi-equilibrium, and also the stochasticity of the system reduces. This results suggest that the phase space of the system is effectively not ergodic and the system with large degreees of freedom approaches to the near-integrable one.Comment: 21pages + 7 figures (available upon request), revtex, submitted to Physical Review

Relaxation processes in one-dimensional self-gravitating many-body systems

Though one dimensional self-gravitating $N$-body systems have been studied for three decade, the nature of relaxation was still unclear. There were inconsistent results about relaxation time; some initial state relaxed in the time scale $T\sim N\,t_c$, but another state did not relax even after $T\sim N^2\,t_c$, where $t_c$ is the crossing time. The water-bag distribution was believed not to relax after $T\sim N^2\,t_c$. In our previous paper, however, we found there are two different relaxation times in the water-bag distribution;in the faster relaxation ( microscopic relaxation ) the equipartition of energy distribution is attains but the macroscopic distribution turns into the isothermal distribution in the later relaxation (macroscopic relaxation). In this paper, we investigated the properties of the two relaxation. We found that the microscopic relaxation time is $T\sim N\,t_c$, and the macroscopic relaxation time is proportional to $N\,t_c$, thus the water-bag does relax. We can see the inconsistency about the relaxation times is resolved as that we see the two different aspect of relaxations. Further, the physical mechanisms of the relaxations are presented.Comment: 11 pages, uuencoded, compressed Postscript, no figure, figures available at ftp://ferio.mtk.nao.ac.jp/pub/tsuchiya/Tsuchiya95.tar.g

Collisionless Relaxation in Galactic Dynamics and the Evolution of Long Range Order

This talk provides a critical assessment of collisionless galactic dynamics, focusing on the interpretation and limitations of the collisionless Boltzmann equation and the physical mechanisms associated with collisionless relaxation. Numerical and theoretical arguments are presented to motivate the idea that the evolution of a system far from equilibrium should be interpreted as involving nonlinear gravitational Landau damping, which implies a greater overall coherence and remembrance of initial conditions than is implicit in the conventional theory of violent relaxation.Comment: 20 pages, plain latex, no macros required, no figures a talk presented at the 1997 Florida Workshop on Nonlinear Astronomy and Physics, to appear in Annals of the New York Academy of Science

The approach to equilibrium in N-body gravitational systems

The evolution of closed gravitational systems is studied by means of $N$-body simulations. This, as well as being interesting in its own right, provides insight into the dynamical and statistical mechanical properties of gravitational systems: the possibility of the existence of stable equilibrium states and the associated relaxation time would provide an ideal situation where relaxation theory can be tested. Indeed, these states are found to exist for single mass $N$-body systems, and the condition condition for this is simply that obtained from elementary thermodynamical considerations applied to self-gravitating ideal gas spheres. However, even when this condition is satisfied, some initial states may not end as isothermal spheres. It is therefore only a necessary condition. Simple considerations also predict that, for fixed total mass, energy and radius, stable isothermal spheres are unique. Therefore, statistically irreversible perturbations to the density profile caused by the accumulation of massive particles near the centre of multimass systems, destroy these equilibria if the aforementioned quantities are kept fixed. The time-scale for this to happen was found to be remarkably short (a few dynamical times when $N= 2500$) in systems undergoing violent relaxation. The time taken to achieve thermal equilibrium depended on the initial conditions and could be comparable to a dynamical time (even when the conditions for violent relaxation were not satisfied) or the two body relaxation time. The relaxation time for velocity anisotropies was intermediate between these two time-scales, being long compared to the dynamical time but much (about four times) shorter than the time-scale of energy relaxation.Comment: To appear in Physical Review