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A stochastic SIR system with Lévy jumps and distributed delay is developed and employed to study the combined effects of Markovian switching and media coverage on stochastic epidemiological dynamics and outcomes. Stochastic Lyapunov functions are used to prove the existence of a stationary distribution to the positive solution. Sufficient conditions for persistence in mean and the extinction of an infectious disease are also shown. [ABSTRACT FROM AUTHOR]

In this paper, we investigate two stochastic SIR epidemic models with higher order perturbation. For the nonautonomous periodic case of the model, by using Has’minskii’s theory of periodic solution, we show that the system has at least one nontrivial positive T -periodic solution. For the system disturbed by both the white noise and telephone noise, we establish sufficient conditions for positive recurrence and the existence of ergodic stationary distribution of the positive solution. [ABSTRACT FROM AUTHOR]

The wide spread of mobile communication since the late 1980 s raises questions about the effects of electromagnetic fields (EMFs) on the human body. Most studies have focused on the non-thermal effects of electromagnetic radiation (EMR). Low-energy EMFs seem to cause structural and functional changes in the cell membrane of different cell types, leading to abnormal cell response. Such changes within the central nervous system (CNS) and auditory system, which directly receive EMR during mobile phone use, are of particular interest. Various studies suggest that EMR directly affects neurons by reducing the neuronal reactivity, increasing the neural membrane conductivity and prolonging their refractory period. Furthermore, although it has been suggested that EMR is related with increased incidence of specific tumors and can interact with known carcinogenic agents, no conclusive evidence exists supporting its role in carcinogenesis. Therefore, no safe conclusions can be drawn regarding the potential harmful effects of mobile phone use. Experiments are underway by our laboratory to investigate possible effects of mobile phone use on the auditory system and the CNS. These along with other studies are expected to further clarify whether mobile phone use truly presents a health hazard. [ABSTRACT FROM AUTHOR]

In this paper, a method of updating filter coefficients is proposed in which the RLS (Recursive Least Squares) algorithm is applied to a noise canceler with a filter for crosstalk removal. The RLS algorithm has an advantage over the Least Mean Square algorithm by virtue of better convergence. When the filter coefficients are updated including the filter for crosstalk removal, the error signal becomes nonlinear in terms of filter coefficients. Hence, a nonlinear RLS algorithm is derived in which such nonlinearity is taken into account. It is shown that the convergence is further improved in comparison with the conventional RLS algorithm. Finally, a method is proposed to reduce the noise contained in the transmitted voice signals of telephone by means of the present noise canceler and its effectiveness is evaluated. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 86(5): 36–44, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.10039 [ABSTRACT FROM AUTHOR]

This paper discusses the modulated-noise reference unit (MNRLD, which is used to represent quantitatively the effect of the quantization distortion due to voice coding on the voice quality. The noise generation method, which has only implicitly been discussed, is formulated; and the effect of various generation parameters on the voice quality evaluation is examined. The following results are obtained. The noise source has a uniform amplitude distribution which simplifies the digital processing compared to the generation of noise with a Gaussian distribution. The effect on the quality is small even if the noise-generation cycle is short. The simplified method proposed by Bellcore Co., U.S.A., is examined for comparison. It is shown through an international evaluation experiment that there is no significant difference in the result of quality measurement even if the simplified generation method is adopted. [ABSTRACT FROM AUTHOR]

A stochastic competition system with Allee effect and distributed delay is established, which is utilized to investigate combined dynamic effects of telephone noise and Lévy jumps on stochastic population dynamics. Stochastically ultimate boundedness of the positive solution is studied. By constructing appropriate stochastic Lyapunov functions, sufficient conditions for weak persistence of the corresponding competitive population are discussed. • A stochastic dynamical system with Allee effect and distributed delay is proposed. • Combined dynamic effects of telephone noise and Lévy jumps are investigated. • Stochastically ultimate boundedness of solution to stochastic system is discussed. • Sufficient conditions for weak persistence of competitive population are studied. [ABSTRACT FROM AUTHOR]

In this paper, a hybrid stochastic prey–predator system with double time delays and commercial exploitation is established, where combined dynamic effects of telephone noise and Lévy jumps on stochastic population dynamics are taken into accounts. Existence and uniqueness of globally positive solution to the proposed system are investigated. By constructing appropriate stochastic Lyapunov functions, existence of an ergodic and unique stationary distribution of the positive solution is discussed. Sufficient conditions for permanence in mean and extinction of corresponding population are derived. Furthermore, sufficient and necessary criteria for optimal exploitation strategy are studied. Numerical simulations are carried out to show consistency with theoretical analysis. • A hybrid delayed stochastic system with telephone noise and Lévy jumps is studied. • Existence and uniqueness of the globally positive solution are investigated. • Existence and uniqueness of an ergodic stationary distribution are investigated. • Permanence in mean and extinction of the corresponding population are discussed. • Sufficient and necessary criteria for optimal exploitation strategy are studied. [ABSTRACT FROM AUTHOR]