Universality of Zipf's Law

We introduce a simple and generic model that reproduces Zipf's law. By regarding the time evolution of the model as a random walk in the logarithmic scale, we explain theoretically why this model reproduces Zipf's law. The explanation shows that the behavior of the model is very robust and universal.Comment: 5 eps files included. To be published in J. Phys. Soc. Jp

The meta book and size-dependent properties of written language

Evidence is given for a systematic text-length dependence of the power-law index gamma of a single book. The estimated gamma values are consistent with a monotonic decrease from 2 to 1 with increasing length of a text. A direct connection to an extended Heap's law is explored. The infinite book limit is, as a consequence, proposed to be given by gamma = 1 instead of the value gamma=2 expected if the Zipf's law was ubiquitously applicable. In addition we explore the idea that the systematic text-length dependence can be described by a meta book concept, which is an abstract representation reflecting the word-frequency structure of a text. According to this concept the word-frequency distribution of a text, with a certain length written by a single author, has the same characteristics as a text of the same length pulled out from an imaginary complete infinite corpus written by the same author.Comment: 7 pages, 6 figures, 1 tabl

Calibration of vacuum ultraviolet monochromators by the molecular branching- ratio technique

Calibration of vacuum ultraviolet monochromators by molecular branching-ratio techniqu

Excitation of the CO fourth positive band system by electron impact on carbon monoxide and carbon dioxide

Excitation of carbon monoxide fourth positive band system by electron impact on carbon monoxide and carbon dioxid

Deactivation of N2A 3 Sigma u plus molecules in the aurora

Analysis of N2A 3 Sigma u positive molecule deactivation in auroras using atmospheric model based on mass spectrometer measurement

Differential electron flux as determined by auroral observations of the N2 positive and N2/+/ systems

Measurement of relative emission rates of auroral system

Rocket investigation of the auroral green line

Dissociative excitation and recombination reactions of atomic oxygen by auroral electrons, related to auroral green lin

Emergence of Zipf's Law in the Evolution of Communication

Zipf's law seems to be ubiquitous in human languages and appears to be a universal property of complex communicating systems. Following the early proposal made by Zipf concerning the presence of a tension between the efforts of speaker and hearer in a communication system, we introduce evolution by means of a variational approach to the problem based on Kullback's Minimum Discrimination of Information Principle. Therefore, using a formalism fully embedded in the framework of information theory, we demonstrate that Zipf's law is the only expected outcome of an evolving, communicative system under a rigorous definition of the communicative tension described by Zipf.Comment: 7 pages, 2 figure

Testing the robustness of laws of polysemy and brevity versus frequency

The pioneering research of G.K. Zipf on the relationship between word frequency and other word features led to the formulation of various linguistic laws. Here we focus on a couple of them: the meaning-frequency law, i.e. the tendency of more frequent words to be more polysemous, and the law of abbreviation, i.e. the tendency of more frequent words to be shorter. Here we evaluate the robustness of these laws in contexts where they have not been explored yet to our knowledge. The recovery of the laws again in new conditions provides support for the hypothesis that they originate from abstract mechanisms.Peer ReviewedPostprint (author's final draft

Ion composition and ion chemistry in an aurora

Auroral ion distribution and conversion of oxygen protons to nitric oxide proton