As all-optical networks grow with ever increasing ultra-high speed,the communication quality suffers seriously from physical layer impairments( PLIs). The same problem still exists in software defined optical network(...As all-optical networks grow with ever increasing ultra-high speed,the communication quality suffers seriously from physical layer impairments( PLIs). The same problem still exists in software defined optical network( SDON) controlled by OpenFlow. Aimed to solve this problem,a PLIs tolerance based lightpath provision scheme is proposed for OpenFlow controlled optical networks. This proposed approach not only takes the OSNR model to represent those linear PLIs factors,but also introduces those nonlinear factors into the OSNR model. Thus,the proposed scheme is able to cover most PLIs factors of each optical link and conduct optical lightpath provison with better communication quality. Moreover,PLIs tolerance model is also set up and considered in this work with some necessary extension to OpenFlow protocols to achieve better compatibility between physical layer impairments factors and various services connections. Simulation results show that the proposed scheme is able to get better performance in terms of packet loss rate and connection setup time.展开更多
In Physics B 1, Aristotle establishes a detailed definition ofphysis. For that purpose, Aristotle distinguishes physis from rechne and his domain. He did this to offer a satisfactory account of the physical being. In ...In Physics B 1, Aristotle establishes a detailed definition ofphysis. For that purpose, Aristotle distinguishes physis from rechne and his domain. He did this to offer a satisfactory account of the physical being. In this process, phf;sis is defined as an immanent principle of movement and as matter and as form. As matter physis could be understood as ＂the primary underlying matter in each case, of things which have in themselves a source of their movements and changes＂. To consider physis as form Aristotle appeals to four arguments where priority of form over matter appears to be evident and where the identifying of eidos/morphe with to telos/to hou heneka will be crucial, especially for later developments. The reconstruction of Aristotle＇s reasoning on his definition ofphysis in Physics B 1 emphasizing the problems that such effort of definition implies is the purpose of this paper.展开更多
Our ability to arrive at knowledge by chains of judgment is constitutive of our rationality, likewise our ability to discern the self-evidence of logical and arithmetical laws. To count an activity as ＂thinking about...Our ability to arrive at knowledge by chains of judgment is constitutive of our rationality, likewise our ability to discern the self-evidence of logical and arithmetical laws. To count an activity as ＂thinking about the physical world＂ is to hold it assessable in the light of the laws of physics; whereas to count an activity as ＂thinking at all＂ is to hold it assessable in the light of the laws of logic. Thus, the kind of generality that distinguishes logic from the special sciences is a generality in the applicability of the norms it provides. Logical laws are more general than laws of the special sciences because they prescribe universally the way in which one ought to think, if one is to think all. Logicism is usually understood to be the thesis that all, or at least large parts of, mathematics can be reduced to logic. This thesis has two sides： （1） all mathematical concepts can be defined in terms of basic logical concepts; （2） all mathematical theorems can be deduced from basic logical truths. According to logicism all terms, including all mathematical terms, are to be given a definite meaning within the basic system. This paper aims at a comparative analysis of the contributions of Frege and Russell to the development of modem logic by reviewing in some detail their essential features and derivations. Without making any pretensions to proffering a definitive resolution of any puzzles, the discussion will, however, raise some fundamental questions, and offer a critical evaluation of the putative success or failure of the logicist programmes of Frege and Russell.展开更多
This paper contributes to depict the current pattern of applications of digital 3D models for professional research and practice, and for broader dissemination of cultural heritage. Passing from a general review to th...This paper contributes to depict the current pattern of applications of digital 3D models for professional research and practice, and for broader dissemination of cultural heritage. Passing from a general review to the illustration of the background project, named MUSINT, the authors underline the objectives. The present case study primarily aims to share information about valuable archaeological collections which have little visibility. To enhance the project＇s contents, which include a whole set of different artifacts, the authors have reproduced high resolution, faithful and measurable digital models on one side, and on the other, lower resolution and geometrically simplified models are yet completed and very close to reality. The former are meant to implement a scholars＇ archive for further scientific activity. The latter to provide content for virtual exhibitions on the Web or on stand-alone interfaces situated in the actual physical museum spaces. The data acquisition and post-processing methods which have been tested and chosen are here briefly described. Hence, the authors then give an account of the most recurrent problematic issues of the established work-flow and how they should be solved. Touched instances are the delicate placing of the artifacts, which must be digitized, in relation to the triangulation-based laser scanner＇s functionality, the refining operations in order to build a coherent single polygon mesh, the most effective ways to deal with unavoidable missing parts or defected textures in the generated model and so on.展开更多
The arguments in this paper lead to a new definition of thermodynamic equilibrium that remedies the deficiencies of the current forms. This definition relates thermodynamic equilibrium to its physical causes and accou...The arguments in this paper lead to a new definition of thermodynamic equilibrium that remedies the deficiencies of the current forms. This definition relates thermodynamic equilibrium to its physical causes and accounts for all factors that determine it for all types of equilibrium. Standard definitions of thermodynamic equilibrium are incomplete. They do not take account of all factors that determine such equilibriums, discuss the impediments which may prevent them being reached or relate the properties that define equilibriums to the physical reasons that determine them when impediments are present. The laws of thermodynamics determine the requirements for equilibrium. These laws arise from the physical behaviour of the molecules in molecular systems and are consequences of the conservation of energy, the energies of molecules, statistics, Newton＇s laws of motion, and the equi-partition of energy. The standard definition of thermodynamic equilibrium correctly defines equilibrium whenever impediments are not factors. The discussion demonstrates how impediments arise, accounts for their role in defining equilibrium and how they relate to the energies of molecules at the conditions of the system. The new definition applies to all types of equilibrium.展开更多
The law of conservation of energy is one of the most fundamental laws of nature.According to the law of the conservation of energy,the non-linear and non-conservative quasi-variational principle of flexible body dynam...The law of conservation of energy is one of the most fundamental laws of nature.According to the law of the conservation of energy,the non-linear and non-conservative quasi-variational principle of flexible body dynamics is established.The physical meaning of the quasi-stationary value conditions has been explained in non-linear and non-conservative flexible body dynamics.In the case study,the application in spacecraft dynamics is researched.展开更多
Using 1200 CPUs of the National Supercomputer TH-A1 and a parallel integral algorithm based on the 3500th-order Taylor expansion and the 4180-digit multiple precision data,we have done a reliable simulation of chaotic...Using 1200 CPUs of the National Supercomputer TH-A1 and a parallel integral algorithm based on the 3500th-order Taylor expansion and the 4180-digit multiple precision data,we have done a reliable simulation of chaotic solution of Lorenz equation in a rather long interval 0 t 10000 LTU(Lorenz time unit).Such a kind of mathematically reliable chaotic simulation has never been reported.It provides us a numerical benchmark for mathematically reliable long-term prediction of chaos.Besides,it also proposes a safe method for mathematically reliable simulations of chaos in a finite but long enough interval.In addition,our very fine simulations suggest that such a kind of mathematically reliable long-term prediction of chaotic solution might have no physical meanings,because the inherent physical micro-level uncertainty due to thermal fluctuation might quickly transfer into macroscopic uncertainty so that trajectories for a long enough time would be essentially uncertain in physics.展开更多
Symmetries play important roles in modern theories of physical laws. In this paper, we review several experimental tests of important symmetries associated with the gravitational interaction, including the universalit...Symmetries play important roles in modern theories of physical laws. In this paper, we review several experimental tests of important symmetries associated with the gravitational interaction, including the universality of free fall for self-gravitating bodies,time-shift symmetry in the gravitational constant, local position invariance and local Lorentz invariance of gravity, and spacetime translational symmetries. Recent experimental explorations for post-Newtonian gravity are discussed, of which, those from pulsar astronomy are highlighted. All of these tests, of very different aspects of gravity theories, at very different length scales, favor to very high precision the predictions of the strong equivalence principle(SEP) and, in particular, general relativity which embodies SEP completely. As the founding principles of gravity, these symmetries are motivated to be promoted to even stricter tests in future.展开更多
Up to now,the most widely used method for transition prediction is the one based on linear stability theory.When it is applied to three-dimensional boundary layers,one has to choose the direction,or path,along which t...Up to now,the most widely used method for transition prediction is the one based on linear stability theory.When it is applied to three-dimensional boundary layers,one has to choose the direction,or path,along which the growth rate of the disturbance is to be integrated.The direction given by using saddle point method in the theory of complex variable function is seen as mathematically most reasonable.However,unlike the saddle point method applied to water waves,here its physical meaning is not so obvious,as the frequency and wave number may be complex.And on some occasions,in advancing the integration of the growth rate of the disturbance,up to a certain location,one may not be able to continue the integration,because the condition for specifying the direction set by the saddle point method can no longer be satisfied on the basis of continuously varying wave number.In this paper,these two problems are discussed,and suggestions for how to do transition prediction under the latter condition are provided.展开更多
基金Supported by the National High Technology Research and Development Programme of China(No.2012AA050804)
文摘As all-optical networks grow with ever increasing ultra-high speed,the communication quality suffers seriously from physical layer impairments( PLIs). The same problem still exists in software defined optical network( SDON) controlled by OpenFlow. Aimed to solve this problem,a PLIs tolerance based lightpath provision scheme is proposed for OpenFlow controlled optical networks. This proposed approach not only takes the OSNR model to represent those linear PLIs factors,but also introduces those nonlinear factors into the OSNR model. Thus,the proposed scheme is able to cover most PLIs factors of each optical link and conduct optical lightpath provison with better communication quality. Moreover,PLIs tolerance model is also set up and considered in this work with some necessary extension to OpenFlow protocols to achieve better compatibility between physical layer impairments factors and various services connections. Simulation results show that the proposed scheme is able to get better performance in terms of packet loss rate and connection setup time.
文摘In Physics B 1, Aristotle establishes a detailed definition ofphysis. For that purpose, Aristotle distinguishes physis from rechne and his domain. He did this to offer a satisfactory account of the physical being. In this process, phf;sis is defined as an immanent principle of movement and as matter and as form. As matter physis could be understood as ＂the primary underlying matter in each case, of things which have in themselves a source of their movements and changes＂. To consider physis as form Aristotle appeals to four arguments where priority of form over matter appears to be evident and where the identifying of eidos/morphe with to telos/to hou heneka will be crucial, especially for later developments. The reconstruction of Aristotle＇s reasoning on his definition ofphysis in Physics B 1 emphasizing the problems that such effort of definition implies is the purpose of this paper.
文摘Our ability to arrive at knowledge by chains of judgment is constitutive of our rationality, likewise our ability to discern the self-evidence of logical and arithmetical laws. To count an activity as ＂thinking about the physical world＂ is to hold it assessable in the light of the laws of physics; whereas to count an activity as ＂thinking at all＂ is to hold it assessable in the light of the laws of logic. Thus, the kind of generality that distinguishes logic from the special sciences is a generality in the applicability of the norms it provides. Logical laws are more general than laws of the special sciences because they prescribe universally the way in which one ought to think, if one is to think all. Logicism is usually understood to be the thesis that all, or at least large parts of, mathematics can be reduced to logic. This thesis has two sides： （1） all mathematical concepts can be defined in terms of basic logical concepts; （2） all mathematical theorems can be deduced from basic logical truths. According to logicism all terms, including all mathematical terms, are to be given a definite meaning within the basic system. This paper aims at a comparative analysis of the contributions of Frege and Russell to the development of modem logic by reviewing in some detail their essential features and derivations. Without making any pretensions to proffering a definitive resolution of any puzzles, the discussion will, however, raise some fundamental questions, and offer a critical evaluation of the putative success or failure of the logicist programmes of Frege and Russell.
文摘This paper contributes to depict the current pattern of applications of digital 3D models for professional research and practice, and for broader dissemination of cultural heritage. Passing from a general review to the illustration of the background project, named MUSINT, the authors underline the objectives. The present case study primarily aims to share information about valuable archaeological collections which have little visibility. To enhance the project＇s contents, which include a whole set of different artifacts, the authors have reproduced high resolution, faithful and measurable digital models on one side, and on the other, lower resolution and geometrically simplified models are yet completed and very close to reality. The former are meant to implement a scholars＇ archive for further scientific activity. The latter to provide content for virtual exhibitions on the Web or on stand-alone interfaces situated in the actual physical museum spaces. The data acquisition and post-processing methods which have been tested and chosen are here briefly described. Hence, the authors then give an account of the most recurrent problematic issues of the established work-flow and how they should be solved. Touched instances are the delicate placing of the artifacts, which must be digitized, in relation to the triangulation-based laser scanner＇s functionality, the refining operations in order to build a coherent single polygon mesh, the most effective ways to deal with unavoidable missing parts or defected textures in the generated model and so on.
文摘The arguments in this paper lead to a new definition of thermodynamic equilibrium that remedies the deficiencies of the current forms. This definition relates thermodynamic equilibrium to its physical causes and accounts for all factors that determine it for all types of equilibrium. Standard definitions of thermodynamic equilibrium are incomplete. They do not take account of all factors that determine such equilibriums, discuss the impediments which may prevent them being reached or relate the properties that define equilibriums to the physical reasons that determine them when impediments are present. The laws of thermodynamics determine the requirements for equilibrium. These laws arise from the physical behaviour of the molecules in molecular systems and are consequences of the conservation of energy, the energies of molecules, statistics, Newton＇s laws of motion, and the equi-partition of energy. The standard definition of thermodynamic equilibrium correctly defines equilibrium whenever impediments are not factors. The discussion demonstrates how impediments arise, accounts for their role in defining equilibrium and how they relate to the energies of molecules at the conditions of the system. The new definition applies to all types of equilibrium.
基金supported by the National Natural Science Foundation of China(Grant No.10272034)the Fundamental Research Funds for the Central Universities of China(Grant No.HEUCF130205)
文摘The law of conservation of energy is one of the most fundamental laws of nature.According to the law of the conservation of energy,the non-linear and non-conservative quasi-variational principle of flexible body dynamics is established.The physical meaning of the quasi-stationary value conditions has been explained in non-linear and non-conservative flexible body dynamics.In the case study,the application in spacecraft dynamics is researched.
基金partly supported by National Natural Science Foundation of China (Grant No. 11272209)National Basic Research Program of China (Grant No. 2011CB309704)State Key Laboratory of Ocean Engineering of China (Grant No. GKZD010056).
文摘Using 1200 CPUs of the National Supercomputer TH-A1 and a parallel integral algorithm based on the 3500th-order Taylor expansion and the 4180-digit multiple precision data,we have done a reliable simulation of chaotic solution of Lorenz equation in a rather long interval 0 t 10000 LTU(Lorenz time unit).Such a kind of mathematically reliable chaotic simulation has never been reported.It provides us a numerical benchmark for mathematically reliable long-term prediction of chaos.Besides,it also proposes a safe method for mathematically reliable simulations of chaos in a finite but long enough interval.In addition,our very fine simulations suggest that such a kind of mathematically reliable long-term prediction of chaotic solution might have no physical meanings,because the inherent physical micro-level uncertainty due to thermal fluctuation might quickly transfer into macroscopic uncertainty so that trajectories for a long enough time would be essentially uncertain in physics.
文摘Symmetries play important roles in modern theories of physical laws. In this paper, we review several experimental tests of important symmetries associated with the gravitational interaction, including the universality of free fall for self-gravitating bodies,time-shift symmetry in the gravitational constant, local position invariance and local Lorentz invariance of gravity, and spacetime translational symmetries. Recent experimental explorations for post-Newtonian gravity are discussed, of which, those from pulsar astronomy are highlighted. All of these tests, of very different aspects of gravity theories, at very different length scales, favor to very high precision the predictions of the strong equivalence principle(SEP) and, in particular, general relativity which embodies SEP completely. As the founding principles of gravity, these symmetries are motivated to be promoted to even stricter tests in future.
基金supported by the National Natural Science Foundation of China (Grant Nos. 11002098 and 11332007)
文摘Up to now,the most widely used method for transition prediction is the one based on linear stability theory.When it is applied to three-dimensional boundary layers,one has to choose the direction,or path,along which the growth rate of the disturbance is to be integrated.The direction given by using saddle point method in the theory of complex variable function is seen as mathematically most reasonable.However,unlike the saddle point method applied to water waves,here its physical meaning is not so obvious,as the frequency and wave number may be complex.And on some occasions,in advancing the integration of the growth rate of the disturbance,up to a certain location,one may not be able to continue the integration,because the condition for specifying the direction set by the saddle point method can no longer be satisfied on the basis of continuously varying wave number.In this paper,these two problems are discussed,and suggestions for how to do transition prediction under the latter condition are provided.
