Author pages are created from data sourced from our academic publisher partnerships and public sources.

- Publications
- Influence

Design of spread-spectrum sequences using chaotic dynamical systems and ergodic theory

- Chi-Chung Chen, K. Yao, K. Umeno, E. Biglieri
- Mathematics
- 1 September 2001

A new design methodology for the design of optimal spread-spectrum sequences for asynchronous code-division multiple access (A-CDMA) and chip-synchronous CDMA (CS-CDMA) systems is proposed. We derive… Expand

METHOD OF CONSTRUCTING EXACTLY SOLVABLE CHAOS

- K. Umeno
- Physics, Mathematics
- 3 October 1996

We present a new systematic method of constructing rational mappings as ergordic transformations with nonuniform invariant measures on the unit interval [0,1]. As a result, we obtain a two-parameter… Expand

Chaotic Monte Carlo Computation: A Dynamical Effect of Random-Number Generations

- K. Umeno
- Physics, Mathematics
- 10 December 1998

Chaotic maps with absolutely continuous invariant probability measures are implemented as random-number generators for Monte Carlo computation. We observe that such Monte Carlo computation based on… Expand

Blind source separation of chaotic laser signals by independent component analysis.

- Masahiko Kuraya, A. Uchida, S. Yoshimori, K. Umeno
- Medicine, Physics
- Optics express
- 21 January 2008

We experimentally demonstrate blind source separation of chaos generated in Nd:YVO(4) microchip solid-state lasers by using independent component analysis. Two chaotic source signals are linearly… Expand

Corrections of the NIST Statistical Test Suite for Randomness

- Song-Ju Kim, K. Umeno, A. Hasegawa
- Physics, Computer Science
- IACR Cryptol. ePrint Arch.
- 27 January 2004

It is well known that the NIST statistical test suite was used for the evaluation of AES candidate algorithms. We have found that the test setting of Discrete Fourier Transform test and Lempel-Ziv… Expand

Spreading sequences using periodic orbits of chaos for CDMA

- K. Umeno, K. Kitayama
- Mathematics
- 1 April 1999

A new family of spreading sequences, which are generated by periodic points of a special class of chaotic dynamics, is discovered. It is shown that the chaotic sequences can have better correlation… Expand

Non-integrable character of Hamiltonian systems with global and symmetric coupling

- K. Umeno
- Mathematics
- 1 April 1995

Abstract A new sufficient condition to prove non-integrability of Hamiltonian systems with symmetric variational equations is proposed. Though the present condition is taken as an extension of Ziglin… Expand

Hippocampal place cell activity during chasing of a moving object associated with reward in rats

- S. Ho, E. Hori, T. Kobayashi, K. Umeno, H. Nishijo
- Medicine, Biology
- Neuroscience
- 11 November 2008

Hippocampal place cells encode location of animals in the environment. However, it remains unknown whether the hippocampal place cells encode a continuously moving object in the environment. To… Expand

Construction of Optimal Chaotic Spreading Sequence Using Lebesgue Spectrum Filter

- K. Umeno, A. Yamaguchi
- Mathematics
- 1 April 2002

- 14
- 1

Higher-Order Decomposition Theory of Exponential Operators and Its Applications to QMC and Nonlinear Dynamics

A general theory of higher-order decomposition of exponential operators and symplectic integrators is reviewed briefly. Some explicit formulas are given up to the tenth order. An application of these… Expand