Jan Tobochnik

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The network of patents connected by citations is an evolving graph, which provides a representation of the innovation process. A patent citing another implies that the cited patent reflects a piece of previously existing knowledge that the citing patent builds upon. A methodology presented here (1) identifies actual clusters of patents: i.e., technological(More)
This paper reports results of a network theory approach to the study of the United States patent system. We model the patent citation network as a discrete time, discrete space stochastic dynamic system. From data on more than 2 million patents and their citations, we extract an attractiveness function, A(k, l), which determines the likelihood that a patent(More)
This Article reports an empirical study of the network composed of patent “nodes” and citation “links” between them. It builds on an earlier study in which we argued that trends in the growth of the patent citation network provide evidence that the explosive growth in patenting in the late twentieth century was due at least in part to the issuance of(More)
1 Department of Biophysics, KFKI Research Institute for Particle and Nuclear Physics of the Hungarian Academy of Sciences, Budapest, Hungary 2 Center for Complex Systems Studies, Kalamazoo College, Kalamazoo, MI, USA 3 New York University School of Law, New York, NY, USA 4 DePaul University – College of Law, Chicago, IL, USA 5 Departments of Physics and(More)
  • J Tobochnik
  • Physical review. E, Statistical physics, plasmas…
  • 1999
Inelastic collapse is found in a two-dimensional system of inelastic hard disks confined between two walls which act as an energy source. As the coefficient of restitution is lowered, there is a transition between a state containing small collapsed clusters and a state dominated by a large collapsed cluster. The transition is analogous to that of a(More)
By adopting a citation-based recursive ranking method for patents the evolution of new fields of technology can be traced. Specifically, it is demonstrated that the laser/inkjet printer technology emerged from the recombination of two existing technologies: sequential printing and static image production. The dynamics of the citations coming from the(More)
In this study we introduce and analyze the statistical structural properties of a model of growing networks which may be relevant to social networks. At each step a new node is added which selects k possible partners from the existing network and joins them with probability delta by undirected edges. The "activity" of the node ends here; it will get new(More)
W. Klein,1,2 Harvey Gould,3 J. Tobochnik,4 F. J. Alexander,5 M. Anghel,1 and Gregory Johnson3 1Department of Physics and Center for Computational Science, Boston University, Boston, Massachusetts 02215 2CNLS, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 3Department of Physics, Clark University, Worcester, Massachusetts 01610 4Department of(More)