Network calculus is an evolving new methodology for backlog and delay analysis of packet-switching networks. With network calculus we are able to compute tight bounds on delays,backlogs,and effective bandwidths in a l...Network calculus is an evolving new methodology for backlog and delay analysis of packet-switching networks. With network calculus we are able to compute tight bounds on delays,backlogs,and effective bandwidths in a lossless setting applicable to packet-switching networks and better understand some physical properties of networks. In this paper,the basic network calculus concepts of arrival curves and service curves are introduced.Then we provide the approach for modeling leaky-bucket,generic cell rate algorithm(GCRA),constant bit rate(CBR)flow, variable bit rate(VBR) flow with arrival curve.It is shown that all rate-based packet schedulers can be by a simple rate latency service curve.And by applying these fundamental rules of network calculus,bounds on delay, buffer,effective bandwidth for leaky bucket,GCRA,CBR and VBR can be derived and some practical examples are given.Finally,we compare all the results obtained and conclude this paper.展开更多
Experimental study is performed on the probabilistic models for the long fatigue crack growth rates （da/dN） of LZ50 axle steel. An equation for crack growth rate was derived to consider the trend of stress intensity...Experimental study is performed on the probabilistic models for the long fatigue crack growth rates （da/dN） of LZ50 axle steel. An equation for crack growth rate was derived to consider the trend of stress intensity factor range going down to the threshold and the average stress effect. The probabilistic models were presented on the equation. They consist of the probabilistic da/dN-△K relations, the confidence-based da/dN-△K relations, and the probabilistic- and confidence-based da/dN-△K relations. Efforts were made respectively to characterize the effects of probabilistic assessments due to the scattering regularity of test data, the number of sampling, and both of them. These relations can provide wide selections for practice. Analysis on the test data of LZ50 steel indicates that the present models are available and feasible.展开更多
A two-degree-of-freedom system contacting a single stop isconsidered. Quasi-periodic and chaotic behavior of the system in astrong resonance case is investigated by theoretical analysis andnumerical simulation.
The almost sure stability of homogeneous viscoelastic platessubjected to a random wide-band stationary in-plane load isinvestigated. The viscoelastic behavior of the plate is described interms of the Bo- ltzmann super...The almost sure stability of homogeneous viscoelastic platessubjected to a random wide-band stationary in-plane load isinvestigated. The viscoelastic behavior of the plate is described interms of the Bo- ltzmann superposition principle, the relaxationkernels of which are represented by the sums of exponents. On theassumption that the in-plane load is random wide-band stationaryprocess, sufficient conditions for al- Most sure stability ofviscoelastic plates are obtained by the applications of Lyapunov'sdirect method.展开更多
A numerical simulation of stochastic damage evolution process in the condition of low cycle fatigue loading is discussed. The relations between damage variables and micro-cracks are obtained by means of the micro-mech...A numerical simulation of stochastic damage evolution process in the condition of low cycle fatigue loading is discussed. The relations between damage variables and micro-cracks are obtained by means of the micro-mechanics model of the representative volume element proposed by Lemaitre and Dufailly([10]). The stochastic Initial damage values are introduced in consideration of the inherent micro-defects In materials. The model combined with a finite element method is applied to simulate the damage evolution process under low cycle fatigue loading. The micro-cracks on the sur face of a specimen of 19Mn6 alloy steel are measured with a replica technique. The numerical results show that the nonhomogeneity of damage and the localization of the fatigue failure are well shown by the proposed simulations, and the fatigue lives are reasonably predicted.展开更多
A study on fatigue behavior of unbonded partially prestressed concrete beams is presented. Model tests have been carried out in static loading and cyclic compressive loading on 15 beams with flexure. The ratios of the...A study on fatigue behavior of unbonded partially prestressed concrete beams is presented. Model tests have been carried out in static loading and cyclic compressive loading on 15 beams with flexure. The ratios of the lower limit to the upper limit of fatigue load are 0.5 and 0.3 respectively, and the frequencies of cyclic loading are 8 Hz and 4.5 Hz respectively. The experimental results of the strains of the concrete and steel bars, the deflection of test beams, and the crack width of normal section are analyzed. According to statistics and analysis of test results, the corresponding calculation models are developed and presented.展开更多
A new finite element analysis principle based on neural networks is proposed. It can realize the finite element analysis in real time. The neural computation of a simple structure was simulated on digital computer, th...A new finite element analysis principle based on neural networks is proposed. It can realize the finite element analysis in real time. The neural computation of a simple structure was simulated on digital computer, the effect of input parameters on convergent speed and precision was analyzed. Before solving a certain FE problem, the linking weight matrix of the neural net, i.e., the global stiffness matrix of the structure analyzed, must be defined. In this paper, a method which uses the BP net to compute the element stiffness matrix in real time is proposed.展开更多
On the principle of non-incremental algorithm, some basic ideas of process optimal control iterative algorithm, based on the Optimal Control Variational Principle in Mechanics, is proposed in this paper. Then the esse...On the principle of non-incremental algorithm, some basic ideas of process optimal control iterative algorithm, based on the Optimal Control Variational Principle in Mechanics, is proposed in this paper. Then the essential governing equations are presented. This work provides a new method to achieve the numerical solutions of the mechanic of finite deformation.展开更多
By virtue of the singular point theory for one-dimension diffusionprocess and the stochastic averaging approach of energy envelop, thebifurcation behavior of a homoclinic bifurcation system, which is inthe presence of...By virtue of the singular point theory for one-dimension diffusionprocess and the stochastic averaging approach of energy envelop, thebifurcation behavior of a homoclinic bifurcation system, which is inthe presence of parametric white noise and is concealed behind acodimension two bifurcation point, is investigated in this paper.展开更多
Rotary bending fatigue tests were carried out by using smoothspecimens of medium car- bon steel with two ferrite grain sizes. Inorder to clarify the physical background of the scatter in fa- tiguebehavior, the statist...Rotary bending fatigue tests were carried out by using smoothspecimens of medium car- bon steel with two ferrite grain sizes. Inorder to clarify the physical background of the scatter in fa- tiguebehavior, the statistical characteristics of the initiation andgrowth of short fatigue crack were in- vestigated. Results show thatthe short crack initiation and growth life distribution can beexpressed by two-or three-parameter Weibull distribution. The Weibulldistribution of the mixed type is well fitted to the crack lengthdistribution for both steels. The knee values of Weibull plots arerelated to the grain size.展开更多
QUANTIZED radiation fields exhibiting nonclassical properties have been of great theoretical andexperimental interest in the last two decades. It is shown that various nonclassical states suchas squeezed state and Sch...QUANTIZED radiation fields exhibiting nonclassical properties have been of great theoretical andexperimental interest in the last two decades. It is shown that various nonclassical states suchas squeezed state and Schrodinger cat state can be generated out of coherent state in thenonlinear process of the interaction of atom and field although the radiation field in a展开更多
PAVELKA in ref. [1] established a propositional logic system whose truth values domain is an enriched residuated lattice and obtained some beautiful results. In order to study more general lattice valued logic systems...PAVELKA in ref. [1] established a propositional logic system whose truth values domain is an enriched residuated lattice and obtained some beautiful results. In order to study more general lattice valued logic systems, we proposed the concept of lattice implication algebra, discussed the corresponding lattice valued propositional logic system, and established a展开更多
基金supported in part by the development Foundation of Southwest Jiaotong Universitythe National Natural Science Foundation of China under Grant No.60572143
文摘Network calculus is an evolving new methodology for backlog and delay analysis of packet-switching networks. With network calculus we are able to compute tight bounds on delays,backlogs,and effective bandwidths in a lossless setting applicable to packet-switching networks and better understand some physical properties of networks. In this paper,the basic network calculus concepts of arrival curves and service curves are introduced.Then we provide the approach for modeling leaky-bucket,generic cell rate algorithm(GCRA),constant bit rate(CBR)flow, variable bit rate(VBR) flow with arrival curve.It is shown that all rate-based packet schedulers can be by a simple rate latency service curve.And by applying these fundamental rules of network calculus,bounds on delay, buffer,effective bandwidth for leaky bucket,GCRA,CBR and VBR can be derived and some practical examples are given.Finally,we compare all the results obtained and conclude this paper.
基金国家自然科学基金，Special Foundation of National Excellent Ph.D.Thesis，Outstanding Young Teachers of Ministry of Education of China
文摘Experimental study is performed on the probabilistic models for the long fatigue crack growth rates （da/dN） of LZ50 axle steel. An equation for crack growth rate was derived to consider the trend of stress intensity factor range going down to the threshold and the average stress effect. The probabilistic models were presented on the equation. They consist of the probabilistic da/dN-△K relations, the confidence-based da/dN-△K relations, and the probabilistic- and confidence-based da/dN-△K relations. Efforts were made respectively to characterize the effects of probabilistic assessments due to the scattering regularity of test data, the number of sampling, and both of them. These relations can provide wide selections for practice. Analysis on the test data of LZ50 steel indicates that the present models are available and feasible.
基金the National Natural Science Foundation of China(19672052)
文摘A two-degree-of-freedom system contacting a single stop isconsidered. Quasi-periodic and chaotic behavior of the system in astrong resonance case is investigated by theoretical analysis andnumerical simulation.
基金the National Natural Science Foundation of China (No.59635140)the National Postdoctoral Foundation.
文摘The almost sure stability of homogeneous viscoelastic platessubjected to a random wide-band stationary in-plane load isinvestigated. The viscoelastic behavior of the plate is described interms of the Bo- ltzmann superposition principle, the relaxationkernels of which are represented by the sums of exponents. On theassumption that the in-plane load is random wide-band stationaryprocess, sufficient conditions for al- Most sure stability ofviscoelastic plates are obtained by the applications of Lyapunov'sdirect method.
文摘A numerical simulation of stochastic damage evolution process in the condition of low cycle fatigue loading is discussed. The relations between damage variables and micro-cracks are obtained by means of the micro-mechanics model of the representative volume element proposed by Lemaitre and Dufailly([10]). The stochastic Initial damage values are introduced in consideration of the inherent micro-defects In materials. The model combined with a finite element method is applied to simulate the damage evolution process under low cycle fatigue loading. The micro-cracks on the sur face of a specimen of 19Mn6 alloy steel are measured with a replica technique. The numerical results show that the nonhomogeneity of damage and the localization of the fatigue failure are well shown by the proposed simulations, and the fatigue lives are reasonably predicted.
文摘A study on fatigue behavior of unbonded partially prestressed concrete beams is presented. Model tests have been carried out in static loading and cyclic compressive loading on 15 beams with flexure. The ratios of the lower limit to the upper limit of fatigue load are 0.5 and 0.3 respectively, and the frequencies of cyclic loading are 8 Hz and 4.5 Hz respectively. The experimental results of the strains of the concrete and steel bars, the deflection of test beams, and the crack width of normal section are analyzed. According to statistics and analysis of test results, the corresponding calculation models are developed and presented.
文摘A new finite element analysis principle based on neural networks is proposed. It can realize the finite element analysis in real time. The neural computation of a simple structure was simulated on digital computer, the effect of input parameters on convergent speed and precision was analyzed. Before solving a certain FE problem, the linking weight matrix of the neural net, i.e., the global stiffness matrix of the structure analyzed, must be defined. In this paper, a method which uses the BP net to compute the element stiffness matrix in real time is proposed.
基金the National Natural Science Foundation of China(Grant No.594305050).
文摘On the principle of non-incremental algorithm, some basic ideas of process optimal control iterative algorithm, based on the Optimal Control Variational Principle in Mechanics, is proposed in this paper. Then the essential governing equations are presented. This work provides a new method to achieve the numerical solutions of the mechanic of finite deformation.
基金Supported by the National Science Foundation of China under Grant No.19602016
文摘By virtue of the singular point theory for one-dimension diffusionprocess and the stochastic averaging approach of energy envelop, thebifurcation behavior of a homoclinic bifurcation system, which is inthe presence of parametric white noise and is concealed behind acodimension two bifurcation point, is investigated in this paper.
文摘Rotary bending fatigue tests were carried out by using smoothspecimens of medium car- bon steel with two ferrite grain sizes. Inorder to clarify the physical background of the scatter in fa- tiguebehavior, the statistical characteristics of the initiation andgrowth of short fatigue crack were in- vestigated. Results show thatthe short crack initiation and growth life distribution can beexpressed by two-or three-parameter Weibull distribution. The Weibulldistribution of the mixed type is well fitted to the crack lengthdistribution for both steels. The knee values of Weibull plots arerelated to the grain size.
文摘QUANTIZED radiation fields exhibiting nonclassical properties have been of great theoretical andexperimental interest in the last two decades. It is shown that various nonclassical states suchas squeezed state and Schrodinger cat state can be generated out of coherent state in thenonlinear process of the interaction of atom and field although the radiation field in a
文摘PAVELKA in ref. [1] established a propositional logic system whose truth values domain is an enriched residuated lattice and obtained some beautiful results. In order to study more general lattice valued logic systems, we proposed the concept of lattice implication algebra, discussed the corresponding lattice valued propositional logic system, and established a
