The effect of signal modulating noise in bistable stochastic resonance systems was studied theoretically and experimentally. A mathematical analysis was made on the bistable stochastic resonance model with small syste...The effect of signal modulating noise in bistable stochastic resonance systems was studied theoretically and experimentally. A mathematical analysis was made on the bistable stochastic resonance model with small system parameters. An analogue circuit was designed to perform the effect. The effect of signal modulating noise was shown in the analog simulation experiment. The analog experiment was conducted for two sinusoidal signals with different frequencies. The results show that there are a sinusoidal component corresponding to the input sinusoidal signal and a noise component presented as a Wiener process corresponding to the input white noise in the system output. By properly selecting system parameters, the effect of signal modulating noise can be manifested in the system output.展开更多
This paper expounded in detail the principle of energy spectrum analysis based on discrete wavelet transformation and multiresolution analysis. In the aspect of feature extraction method study, with investigating the ...This paper expounded in detail the principle of energy spectrum analysis based on discrete wavelet transformation and multiresolution analysis. In the aspect of feature extraction method study, with investigating the feature of impact factor in vibration signals and considering the non-placidity and non-linear of vibration diagnosis signals, the authors import wavelet analysis and fractal theory as the tools of faulty signal feature description. Experimental results proved the validity of this method. To some extent, this method provides a good approach of resolving the wholesome problem of fault feature symptom description.展开更多
In this paper, we investigate the connectivity of vehicular ad hoc networks in free-flow traffic situation with channel randonmess. In order to illustrate the realistic environment, we consider that vehicles are distr...In this paper, we investigate the connectivity of vehicular ad hoc networks in free-flow traffic situation with channel randonmess. In order to illustrate the realistic environment, we consider that vehicles are distributed in free-flow highway according to a Poisson point process, and signal propagation between connected vehicles is subjected to log-normal shadowing effects. We obtain the distribution of the space headway between successive vehicles and the distribution of signal coverage, which allows us to use the equivalent M/G/z~ queue theory to model the connectivity of VANETs in the form of average broadcast percolation distance and average number of connected nodes. Then, extensive simulation studies are conducted to evaluate the obtained results. The analytical model presented here is able to describe the impact of various system parameters, including traffic parameters and signal propagation parameters on the con- nectivity. We use our analytical results, along with the common signal propagation data, to understand impact of channel randomness on the connectivity of VANETs.展开更多
It has been 25years since the formalization of the Sensory Drive hypothesis was published in the American Naturalist （1992）. Since then, there has been an explosion of research identifying its utility in contributin...It has been 25years since the formalization of the Sensory Drive hypothesis was published in the American Naturalist （1992）. Since then, there has been an explosion of research identifying its utility in contributing to our understanding of inter- and intra-specific variation in sensory systems and signaling properties. The main tenet of Sensory Drive is that environmental characteristics will influence the evolutionary trajectory of both sensory （detecting capabilities） and signaling （detectable features and behaviors） traits in predictable directions. We review the accumulating evidence in 154 studies addressing these questions and categorized their approach in terms of testing for environmental influence on sensory tuning, signal characteristics, or both. For the subset of studies that examined sensory tuning, there was greater support for Sensory Drive processes shaping visual than auditory tuning, and it was more prevalent in aquatic than terrestrial habitats. Terrestrial habitats and visual traits were the prevalent habitat and sensory modality in the 104 studies showing support for environmental influence on signaling properties. An additional 19 studies that found no supporting evidence for environmental influence on signaling traits were all based in terrestrial ecosystems and almost exclusively involved auditory signals. Only 29 studies examined the complete coevolutionary process between sensory and signaling traits and were dominated by fish visual communication. We discuss biophysical factors that may contribute to the visual and aquatic bias for Sensory Drive evidence, as well as biotic factors that may contribute to the lack of Sensory Drive processes in terrestrial acoustic signaling systems.展开更多
Many interacting biomolecular components in cells form different positive or negative feedback loops. When biological signals transduce through cascades consisting of various loops they will be affected or even distor...Many interacting biomolecular components in cells form different positive or negative feedback loops. When biological signals transduce through cascades consisting of various loops they will be affected or even distorted. Especially, how to process various signals buried in various intrinsic and extrinsic noises is an important issue. This paper analyzes how the response time influences noise filtering ability and how to enhance the ability by coupling different feedback loops. A parameter to measure the response time of the signal transduction, i.e., τ0.9, and its relationship between the response time and noise filtering will be discussed. The authors show clearly that the longer the response time is, the better the ability to filter noises will be. Therefore, to enhance the ability to filter noises, the authors can prolong the response time by coupling different positive or negative feedback loops. The results provide a possible approach to enhance the ability to filter noises in larger biomolecular networks.展开更多
基金Project (10276032) supportedjointly by the National Natural Science Foundation of China and by the Science Foundationof China Academy of Engineering Physics NSAFproject(2005038228) supported by Postdoctoral Science Foundation of China projectsupported by the Postdoctoral Science Foundation of Central South University(2005)
文摘The effect of signal modulating noise in bistable stochastic resonance systems was studied theoretically and experimentally. A mathematical analysis was made on the bistable stochastic resonance model with small system parameters. An analogue circuit was designed to perform the effect. The effect of signal modulating noise was shown in the analog simulation experiment. The analog experiment was conducted for two sinusoidal signals with different frequencies. The results show that there are a sinusoidal component corresponding to the input sinusoidal signal and a noise component presented as a Wiener process corresponding to the input white noise in the system output. By properly selecting system parameters, the effect of signal modulating noise can be manifested in the system output.
文摘This paper expounded in detail the principle of energy spectrum analysis based on discrete wavelet transformation and multiresolution analysis. In the aspect of feature extraction method study, with investigating the feature of impact factor in vibration signals and considering the non-placidity and non-linear of vibration diagnosis signals, the authors import wavelet analysis and fractal theory as the tools of faulty signal feature description. Experimental results proved the validity of this method. To some extent, this method provides a good approach of resolving the wholesome problem of fault feature symptom description.
基金Supported by the National Natural Science Foundation of China (No. 60873192,61070182)
文摘In this paper, we investigate the connectivity of vehicular ad hoc networks in free-flow traffic situation with channel randonmess. In order to illustrate the realistic environment, we consider that vehicles are distributed in free-flow highway according to a Poisson point process, and signal propagation between connected vehicles is subjected to log-normal shadowing effects. We obtain the distribution of the space headway between successive vehicles and the distribution of signal coverage, which allows us to use the equivalent M/G/z~ queue theory to model the connectivity of VANETs in the form of average broadcast percolation distance and average number of connected nodes. Then, extensive simulation studies are conducted to evaluate the obtained results. The analytical model presented here is able to describe the impact of various system parameters, including traffic parameters and signal propagation parameters on the con- nectivity. We use our analytical results, along with the common signal propagation data, to understand impact of channel randomness on the connectivity of VANETs.
文摘It has been 25years since the formalization of the Sensory Drive hypothesis was published in the American Naturalist （1992）. Since then, there has been an explosion of research identifying its utility in contributing to our understanding of inter- and intra-specific variation in sensory systems and signaling properties. The main tenet of Sensory Drive is that environmental characteristics will influence the evolutionary trajectory of both sensory （detecting capabilities） and signaling （detectable features and behaviors） traits in predictable directions. We review the accumulating evidence in 154 studies addressing these questions and categorized their approach in terms of testing for environmental influence on sensory tuning, signal characteristics, or both. For the subset of studies that examined sensory tuning, there was greater support for Sensory Drive processes shaping visual than auditory tuning, and it was more prevalent in aquatic than terrestrial habitats. Terrestrial habitats and visual traits were the prevalent habitat and sensory modality in the 104 studies showing support for environmental influence on signaling properties. An additional 19 studies that found no supporting evidence for environmental influence on signaling traits were all based in terrestrial ecosystems and almost exclusively involved auditory signals. Only 29 studies examined the complete coevolutionary process between sensory and signaling traits and were dominated by fish visual communication. We discuss biophysical factors that may contribute to the visual and aquatic bias for Sensory Drive evidence, as well as biotic factors that may contribute to the lack of Sensory Drive processes in terrestrial acoustic signaling systems.
基金This research is supported by the National Natural Science Foundation of China under Grant No. 10832006, Youth Research under Grant No. 10701052, and Shanghai Pujiang Program.
文摘Many interacting biomolecular components in cells form different positive or negative feedback loops. When biological signals transduce through cascades consisting of various loops they will be affected or even distorted. Especially, how to process various signals buried in various intrinsic and extrinsic noises is an important issue. This paper analyzes how the response time influences noise filtering ability and how to enhance the ability by coupling different feedback loops. A parameter to measure the response time of the signal transduction, i.e., τ0.9, and its relationship between the response time and noise filtering will be discussed. The authors show clearly that the longer the response time is, the better the ability to filter noises will be. Therefore, to enhance the ability to filter noises, the authors can prolong the response time by coupling different positive or negative feedback loops. The results provide a possible approach to enhance the ability to filter noises in larger biomolecular networks.
