The evolutionary dynamics first conceived by Darwin and Wallace, referring to as Darwinian dynamics in the present paper, has been found to be universally valid in biology. The statistical mechanics and thermodynamics...The evolutionary dynamics first conceived by Darwin and Wallace, referring to as Darwinian dynamics in the present paper, has been found to be universally valid in biology. The statistical mechanics and thermodynamics, while enormous successful in physics, have been in an awkward situation of wanting a consistent dynamical understanding. Here we present from a formal point of view an exploration of the connection between thermodynamics and Darwinian dynamics and a few related topics. We first show that the stochasticity in Darwinian dynamics implies the existence temperature, hence the canonical distribution of Boltzmann-Gibbs type. In term of relative entropy the Second Law of thermodynamics is dynamically demonstrated without detailed balance condition, and is valid regardless of size of the system. In particular, the dynamical component responsible for breaking detailed balance condition does not contribute to the change of the relative entropy. Two types of stochastic dynamical equalities of current interest are explicitly discussed in the present approach： One is based on Feynman-Kac formula and another is a generalization of Einstein relation. Both are directly accessible to experimental tests. Our demonstration indicates that Darwinian dynamics represents logically a simple and straightforward starting point for statistical mechanics and thermodynamics and is complementary to and consistent with conservative dynamics that dominates the physical sciences. Present exploration suggests the existence of a unified stochastic dynamical framework both near and far from equilibrium.展开更多
The peer-to-peer（P2P） file-sharing network as a vehicle of disseminating files has become very popular. The appearance of dozens of kinds of passive worms on this network has, however, made it unsecured. This proble...The peer-to-peer（P2P） file-sharing network as a vehicle of disseminating files has become very popular. The appearance of dozens of kinds of passive worms on this network has, however, made it unsecured. This problem has been paid attention and a few of models for passive worm propagation has been presented. Unfortunately, the dynamic properties of this network are ignored in these models. Given the fact, the characteristics of both this network and the passive worm are identified, and on this basis a new mathematical model of passive worm propagation on the P2P network is presented in applying epidemiology in this paper. Note that the dynamic properties of this network are considered in the presented model. The model has been validated by large scale simulation experiments, which demonstrates that the presented model may be used for analyzing the behaviors of passive worms and predicting the trend of their propagation.展开更多
The purpose of the present paper is to investigate the multimodality in college English textbooks. Because multimodality is closely associated with college English teaching and learning, it is necessary to probe into ...The purpose of the present paper is to investigate the multimodality in college English textbooks. Because multimodality is closely associated with college English teaching and learning, it is necessary to probe into the multimodality in college English books. First, the study showed that the images in college English textbooks have the following functions： to illustrate the text, to consolidate the information in the text, to aestheticize the text, as well as to collaborate with the text to establish harmony between the author and the reader, therefore to convey the author＇s intentions well. Second, the study showed that the multimodality in college English textbooks reflects power relation and solidarity relation between the author and the reader. On the one hand, multimodality in college English textbooks implies unequal power relationships which are represented by unequal power opportunities for the author to select images while the reader has little influence. On the other hand, the learning activities provide a lot of chances for the reader to make contact with the images, hence establishing a familiar and harmonious relationship between the reader and the author. The findings of the present study have useful implications for college English teaching and learning and imply the need for further studies in this field.展开更多
基金The project supported in part by USA NIH Grant under HG002894
文摘The evolutionary dynamics first conceived by Darwin and Wallace, referring to as Darwinian dynamics in the present paper, has been found to be universally valid in biology. The statistical mechanics and thermodynamics, while enormous successful in physics, have been in an awkward situation of wanting a consistent dynamical understanding. Here we present from a formal point of view an exploration of the connection between thermodynamics and Darwinian dynamics and a few related topics. We first show that the stochasticity in Darwinian dynamics implies the existence temperature, hence the canonical distribution of Boltzmann-Gibbs type. In term of relative entropy the Second Law of thermodynamics is dynamically demonstrated without detailed balance condition, and is valid regardless of size of the system. In particular, the dynamical component responsible for breaking detailed balance condition does not contribute to the change of the relative entropy. Two types of stochastic dynamical equalities of current interest are explicitly discussed in the present approach： One is based on Feynman-Kac formula and another is a generalization of Einstein relation. Both are directly accessible to experimental tests. Our demonstration indicates that Darwinian dynamics represents logically a simple and straightforward starting point for statistical mechanics and thermodynamics and is complementary to and consistent with conservative dynamics that dominates the physical sciences. Present exploration suggests the existence of a unified stochastic dynamical framework both near and far from equilibrium.
文摘The peer-to-peer（P2P） file-sharing network as a vehicle of disseminating files has become very popular. The appearance of dozens of kinds of passive worms on this network has, however, made it unsecured. This problem has been paid attention and a few of models for passive worm propagation has been presented. Unfortunately, the dynamic properties of this network are ignored in these models. Given the fact, the characteristics of both this network and the passive worm are identified, and on this basis a new mathematical model of passive worm propagation on the P2P network is presented in applying epidemiology in this paper. Note that the dynamic properties of this network are considered in the presented model. The model has been validated by large scale simulation experiments, which demonstrates that the presented model may be used for analyzing the behaviors of passive worms and predicting the trend of their propagation.
文摘The purpose of the present paper is to investigate the multimodality in college English textbooks. Because multimodality is closely associated with college English teaching and learning, it is necessary to probe into the multimodality in college English books. First, the study showed that the images in college English textbooks have the following functions： to illustrate the text, to consolidate the information in the text, to aestheticize the text, as well as to collaborate with the text to establish harmony between the author and the reader, therefore to convey the author＇s intentions well. Second, the study showed that the multimodality in college English textbooks reflects power relation and solidarity relation between the author and the reader. On the one hand, multimodality in college English textbooks implies unequal power relationships which are represented by unequal power opportunities for the author to select images while the reader has little influence. On the other hand, the learning activities provide a lot of chances for the reader to make contact with the images, hence establishing a familiar and harmonious relationship between the reader and the author. The findings of the present study have useful implications for college English teaching and learning and imply the need for further studies in this field.
