In this paper, the existence and uniqueness of the local generalized solution of the initial boundary value problem for a nonlinear hyperbolic equation are proved by the contraction mapping principle and the sufficien...In this paper, the existence and uniqueness of the local generalized solution of the initial boundary value problem for a nonlinear hyperbolic equation are proved by the contraction mapping principle and the sufficient conditions of blow_up of the solution in finite time are given.展开更多
Ring signature and proxy signature are of vital importance to secure electronic commerce. Recently, the bilinear pairing such as Well pairing or Tate pairing on elliptic curves and hyperelliptic curves is playing an i...Ring signature and proxy signature are of vital importance to secure electronic commerce. Recently, the bilinear pairing such as Well pairing or Tate pairing on elliptic curves and hyperelliptic curves is playing an important role in security solutions. Several ID-based signature schemes have been put forward, many of which are based on bilinear pairings. In key management and moderate security demand scenarios, ID-based public key cryptosystem is more preferable than other public key infrastructure based systems. In this paper, an improved ID-based proxy ring signature scheme from bilinear pairings is proposed which combines the advantages of proxy signature and of ring signatures. Our scheme can guarantee the profits of the proxy signer via preventing the original signer form generating the proxy ring signature. Furthermore, bilinear pairings are introduced to minimize the computation overhead and to improve the related performance of our scheme. In contrast with Zhang＇s scheme, our scheme is a computational efficiency improvement for signature verification because the computational cost of bilinear pairings required is reduced from O（n） to O（ 1 ）. In addition, the proxy ring signature presented in this paper can perfectly satisfy all the security requirements of proxy ring signature, i. e. signer-ambiguity, non-forgeability, verification, non-deniability and distinguishability.展开更多
the close photogrammetric 3-D coordinate measurement is a newmeasuring technology in the fields of the coordinate measurementmachine (CMM) in recent years. In this method, we usually place sometargets on the measured ...the close photogrammetric 3-D coordinate measurement is a newmeasuring technology in the fields of the coordinate measurementmachine (CMM) in recent years. In this method, we usually place sometargets on the measured object and take image of targets to determinethe object coordinate. The subpixel location of target image plays animportant role in high accuracy 3-D coordinate measuring procedure.In this paper, some subpixel location methods are reviewed and somefactors which affect location precision are analyzed.展开更多
The paper deals with two-dimensional （2D） channel estimation of Orthogonal Frequency Division Multiplexing （OFDM） system ill slow fading wireless channel. We concentrate on two channel estimation schemes： Least S...The paper deals with two-dimensional （2D） channel estimation of Orthogonal Frequency Division Multiplexing （OFDM） system ill slow fading wireless channel. We concentrate on two channel estimation schemes： Least Square （LS）＋Weighted BiLinear （WBL） and LS＋Linear Minimum Mean-Squared Error （LMMSE） where the first method is proposed in this paper. After theory analysis and simulation in Typical Urban （TU） channel, we find that LS＋LMMSE achieves the optimal perform- anee by exploiting prior knowledge of channel whereas LS＋WBL, without requiring channel knowl- edge and with only half of the computational amount of LS＋LMMSE, approaches LS＋LMMSE in Bit Error Ratio （BER） performance when the distance of two adjoining pilot symbols along frequency direction is sufficiently small. This makes LS＋WBL very suitable for wideband wireless applications.展开更多
Bifidobacteria play an important role in maintaining human health, and suppress harmful bacteria by controlling the pH of the large intestine. About 14 strains of the Bifidobacteria have been isolated from the faeces ...Bifidobacteria play an important role in maintaining human health, and suppress harmful bacteria by controlling the pH of the large intestine. About 14 strains of the Bifidobacteria have been isolated from the faeces of infants nursed exclusively from the maternal milk （their ages less than 5 months） from commercial French yoghurt （active bifidus] and from milk （celia bifidus） on MRS medium （containing 0.05% cysteine-HC1, with nalidixic acid 2 mg rel）. A total of six strain are strict anaerobic and gram-positive Bifidobacteria, identified as, B. longum （60% of the samples） was the most frequently found species, followed by B. bifidum （21.0%）, B. breve （19%）. These strains were evaluated for potential use as probiotics based on their adhesion to intestinal epithelial cells, resistance towards acidic （resistance to low pH） and bile conditions, pH values ranging from 6.5 to 7, however, these strains are sensitive to the pH 8, Bifidobacterium are mesophiles with optimal growth at 36℃ to 41℃. All isolates studied have a fast growth in glucose.展开更多
Bifidobacteria represent the largest group of human intestinal bacteria. They have an important place in human health and represent the dominant group microflora of the newbom breast-fed. Following the behavior of str...Bifidobacteria represent the largest group of human intestinal bacteria. They have an important place in human health and represent the dominant group microflora of the newbom breast-fed. Following the behavior of strains of Bifidobacteria isolated from the breast-fed infants and from saline rehydration solution was considered in order to develop therapeutic fermented milk. Samples from newborn infants aged 10 months, or from a saline rehydration solution （Celia/Develop ORS） containing Bifidobacteria sold was used and isolated strains belonged to breve and longum species. Those strains showed preferences to neutral pH. They are mesophilic and tolerate high temperatures （42 ℃）. Glucose was commonly carbohydrate used in selective media for Bifidobacteria. Production of titratable acidity and therefore lowering the pH varies from one strain to another.展开更多
By means of an equivalent invariant form of boundary conditions, the authors get the exis- tence and uniqueness of semi-global C1 solution to the mixed initial-boundary value problem for quasilinear hyperbolic systems...By means of an equivalent invariant form of boundary conditions, the authors get the exis- tence and uniqueness of semi-global C1 solution to the mixed initial-boundary value problem for quasilinear hyperbolic systems with general nonlinear boundary conditions.展开更多
By means of the continuous Glimm functional, a proof is given on the global existence of classical solutions to Cauchy problem for general first order quasilinear hyperbolic systems with small initial total variation.
This paper presents a low order stabilized hybrid quadrilateral finite element method for ReissnerMindlin plates based on Hellinger-Reissner variational principle,which includes variables of displacements,shear stress...This paper presents a low order stabilized hybrid quadrilateral finite element method for ReissnerMindlin plates based on Hellinger-Reissner variational principle,which includes variables of displacements,shear stresses and bending moments.The approach uses continuous piecewise isoparametric bilinear interpolations for the approximations of the transverse displacement and rotation.The stabilization achieved by adding a stabilization term of least-squares to the original hybrid scheme,allows independent approximations of the stresses and moments.The stress approximation adopts a piecewise independent 4-parameter mode satisfying an accuracy-enhanced condition.The approximation of moments employs a piecewise-independent 5-parameter mode.This method can be viewed as a stabilized version of the hybrid finite element scheme proposed in [Carstensen C,Xie X,Yu G,et al.A priori and a posteriori analysis for a locking-free low order quadrilateral hybrid finite element for Reissner-Mindlin plates.Comput Methods Appl Mech Engrg,2011,200:1161-1175],where the approximations of stresses and moments are required to satisfy an equilibrium criterion.A priori error analysis shows that the method is uniform with respect to the plate thickness t.Numerical experiments confirm the theoretical results.展开更多
This paper investigates the finite element approximation of a class of parameter estimation problems which is the form of performance as the optimal control problems governed by bilinear parabolic equations,where the ...This paper investigates the finite element approximation of a class of parameter estimation problems which is the form of performance as the optimal control problems governed by bilinear parabolic equations,where the state and co-state are discretized by piecewise linear functions and control is approximated by piecewise constant functions.The authors derive some a priori error estimates for both the control and state approximations.Finally,the numerical experiments verify the theoretical results.展开更多
This paper considers an epidemic model of a vector-borne disease which has the vectormediated transmission only. The incidence term is of the bilinear mass-action form. It is shown that the global dynamics is complete...This paper considers an epidemic model of a vector-borne disease which has the vectormediated transmission only. The incidence term is of the bilinear mass-action form. It is shown that the global dynamics is completely determined by the basic reproduction number Ro. If Ro ≤ 1, the diseasefree equilibrium is globally stable and the disease dies out. If Ro 〉 1, a unique endemic equilibrium is globally stable in the interior of the feasible region and the disease persists at the endemic equilibrium. Numerical simulations are presented to illustrate the results.展开更多
For a class of mixed initial-boundary value problem for general quasilinear hyperbolic sys-tems with zero eigenvalues, the authors establish the local exact controllability with boundary controls acting on one end or ...For a class of mixed initial-boundary value problem for general quasilinear hyperbolic sys-tems with zero eigenvalues, the authors establish the local exact controllability with boundary controls acting on one end or on two ends and internai controls acting on a part of equations in the system.展开更多
Under the internal dissipative condition, the Cauchy problem for inhomogeneous quasilinear hyperbolic systems with small initial data admits a unique global C1 solution, which exponentially decays to zero as t →＋∞,...Under the internal dissipative condition, the Cauchy problem for inhomogeneous quasilinear hyperbolic systems with small initial data admits a unique global C1 solution, which exponentially decays to zero as t →＋∞, while if the coefficient matrix 19 of boundary conditions satisfies the boundary dissipative condition, the mixed initialboundary value problem with small initial data for quasilinear hyperbolic systems with nonlinear terms of at least second order admits a unique global C1 solution, which also exponentially decays to zero as t →＋∞. In this paper, under more general conditions, the authors investigate the combined effect of the internal dissipative condition and the boundary dissipative condition, and prove the global existence and exponential decay of the C1 solution to the mixed initial-boundary value problem for quasilinear hyperbolic systems with small initial data. This stability result is applied to a kind of models, and an example is given to show the possible exponential instability if the corresponding conditions are not satisfied.展开更多
Let B R^n be the unit ball centered at the origin. The authors consider the following biharmonic equation:{?~2u = λ(1 + u)~p in B,u =?u/?ν= 0 on ?B, where p >n+4/ n-4and ν is the outward unit normal vector. It ...Let B R^n be the unit ball centered at the origin. The authors consider the following biharmonic equation:{?~2u = λ(1 + u)~p in B,u =?u/?ν= 0 on ?B, where p >n+4/ n-4and ν is the outward unit normal vector. It is well-known that there exists a λ*> 0 such that the biharmonic equation has a solution for λ∈ (0, λ*) and has a unique weak solution u*with parameter λ = λ*, called the extremal solution. It is proved that u* is singular when n ≥ 13 for p large enough and satisfies u*≤ r^(-4/ (p-1)) - 1 on the unit ball, which actually solve a part of the open problem left in [D`avila, J., Flores, I., Guerra, I., Multiplicity of solutions for a fourth order equation with power-type nonlinearity, Math. Ann., 348(1), 2009, 143–193] .展开更多
文摘In this paper, the existence and uniqueness of the local generalized solution of the initial boundary value problem for a nonlinear hyperbolic equation are proved by the contraction mapping principle and the sufficient conditions of blow_up of the solution in finite time are given.
基金Sponsored by the National Natural Science Foundation of China(Grant No.90104033).
文摘Ring signature and proxy signature are of vital importance to secure electronic commerce. Recently, the bilinear pairing such as Well pairing or Tate pairing on elliptic curves and hyperelliptic curves is playing an important role in security solutions. Several ID-based signature schemes have been put forward, many of which are based on bilinear pairings. In key management and moderate security demand scenarios, ID-based public key cryptosystem is more preferable than other public key infrastructure based systems. In this paper, an improved ID-based proxy ring signature scheme from bilinear pairings is proposed which combines the advantages of proxy signature and of ring signatures. Our scheme can guarantee the profits of the proxy signer via preventing the original signer form generating the proxy ring signature. Furthermore, bilinear pairings are introduced to minimize the computation overhead and to improve the related performance of our scheme. In contrast with Zhang＇s scheme, our scheme is a computational efficiency improvement for signature verification because the computational cost of bilinear pairings required is reduced from O（n） to O（ 1 ）. In addition, the proxy ring signature presented in this paper can perfectly satisfy all the security requirements of proxy ring signature, i. e. signer-ambiguity, non-forgeability, verification, non-deniability and distinguishability.
文摘the close photogrammetric 3-D coordinate measurement is a newmeasuring technology in the fields of the coordinate measurementmachine (CMM) in recent years. In this method, we usually place sometargets on the measured object and take image of targets to determinethe object coordinate. The subpixel location of target image plays animportant role in high accuracy 3-D coordinate measuring procedure.In this paper, some subpixel location methods are reviewed and somefactors which affect location precision are analyzed.
基金Supported by the National Natural Science Foundation of China (No: 60496311).
文摘The paper deals with two-dimensional （2D） channel estimation of Orthogonal Frequency Division Multiplexing （OFDM） system ill slow fading wireless channel. We concentrate on two channel estimation schemes： Least Square （LS）＋Weighted BiLinear （WBL） and LS＋Linear Minimum Mean-Squared Error （LMMSE） where the first method is proposed in this paper. After theory analysis and simulation in Typical Urban （TU） channel, we find that LS＋LMMSE achieves the optimal perform- anee by exploiting prior knowledge of channel whereas LS＋WBL, without requiring channel knowl- edge and with only half of the computational amount of LS＋LMMSE, approaches LS＋LMMSE in Bit Error Ratio （BER） performance when the distance of two adjoining pilot symbols along frequency direction is sufficiently small. This makes LS＋WBL very suitable for wideband wireless applications.
文摘Bifidobacteria play an important role in maintaining human health, and suppress harmful bacteria by controlling the pH of the large intestine. About 14 strains of the Bifidobacteria have been isolated from the faeces of infants nursed exclusively from the maternal milk （their ages less than 5 months） from commercial French yoghurt （active bifidus] and from milk （celia bifidus） on MRS medium （containing 0.05% cysteine-HC1, with nalidixic acid 2 mg rel）. A total of six strain are strict anaerobic and gram-positive Bifidobacteria, identified as, B. longum （60% of the samples） was the most frequently found species, followed by B. bifidum （21.0%）, B. breve （19%）. These strains were evaluated for potential use as probiotics based on their adhesion to intestinal epithelial cells, resistance towards acidic （resistance to low pH） and bile conditions, pH values ranging from 6.5 to 7, however, these strains are sensitive to the pH 8, Bifidobacterium are mesophiles with optimal growth at 36℃ to 41℃. All isolates studied have a fast growth in glucose.
文摘Bifidobacteria represent the largest group of human intestinal bacteria. They have an important place in human health and represent the dominant group microflora of the newbom breast-fed. Following the behavior of strains of Bifidobacteria isolated from the breast-fed infants and from saline rehydration solution was considered in order to develop therapeutic fermented milk. Samples from newborn infants aged 10 months, or from a saline rehydration solution （Celia/Develop ORS） containing Bifidobacteria sold was used and isolated strains belonged to breve and longum species. Those strains showed preferences to neutral pH. They are mesophilic and tolerate high temperatures （42 ℃）. Glucose was commonly carbohydrate used in selective media for Bifidobacteria. Production of titratable acidity and therefore lowering the pH varies from one strain to another.
基金the Special Funds for Major State Basic Research Projects of China.
文摘By means of an equivalent invariant form of boundary conditions, the authors get the exis- tence and uniqueness of semi-global C1 solution to the mixed initial-boundary value problem for quasilinear hyperbolic systems with general nonlinear boundary conditions.
文摘By means of the continuous Glimm functional, a proof is given on the global existence of classical solutions to Cauchy problem for general first order quasilinear hyperbolic systems with small initial total variation.
基金supported by National Natural Science Foundation of China (Grant Nos. 11171239 and 11226333)Scientific Research Foundation for the Returned Overseas Chinese Scholars and Foundation for Excellent Young Scholars of Sichuan University (Grant No. 2011SCU04B28)
文摘This paper presents a low order stabilized hybrid quadrilateral finite element method for ReissnerMindlin plates based on Hellinger-Reissner variational principle,which includes variables of displacements,shear stresses and bending moments.The approach uses continuous piecewise isoparametric bilinear interpolations for the approximations of the transverse displacement and rotation.The stabilization achieved by adding a stabilization term of least-squares to the original hybrid scheme,allows independent approximations of the stresses and moments.The stress approximation adopts a piecewise independent 4-parameter mode satisfying an accuracy-enhanced condition.The approximation of moments employs a piecewise-independent 5-parameter mode.This method can be viewed as a stabilized version of the hybrid finite element scheme proposed in [Carstensen C,Xie X,Yu G,et al.A priori and a posteriori analysis for a locking-free low order quadrilateral hybrid finite element for Reissner-Mindlin plates.Comput Methods Appl Mech Engrg,2011,200:1161-1175],where the approximations of stresses and moments are required to satisfy an equilibrium criterion.A priori error analysis shows that the method is uniform with respect to the plate thickness t.Numerical experiments confirm the theoretical results.
基金supported by the National Natural Science Foundation of China under Grant Nos.11101025,11071080,11171113the National Natural Science Foundation of China under Grant No.11126279+1 种基金the Fundamental Research Funds for the Central Universitiesthe Youth Foundation of Tianyuan Mathematics
文摘This paper investigates the finite element approximation of a class of parameter estimation problems which is the form of performance as the optimal control problems governed by bilinear parabolic equations,where the state and co-state are discretized by piecewise linear functions and control is approximated by piecewise constant functions.The authors derive some a priori error estimates for both the control and state approximations.Finally,the numerical experiments verify the theoretical results.
基金supported by the Natural Science Foundation of China under Grant Nos.10371105 and 10671166the Natural Science Foundation of Henan Province under Grant No.0312002000
文摘This paper considers an epidemic model of a vector-borne disease which has the vectormediated transmission only. The incidence term is of the bilinear mass-action form. It is shown that the global dynamics is completely determined by the basic reproduction number Ro. If Ro ≤ 1, the diseasefree equilibrium is globally stable and the disease dies out. If Ro 〉 1, a unique endemic equilibrium is globally stable in the interior of the feasible region and the disease persists at the endemic equilibrium. Numerical simulations are presented to illustrate the results.
基金the Special Funds for Major State Basic Research Projects of China.
文摘For a class of mixed initial-boundary value problem for general quasilinear hyperbolic sys-tems with zero eigenvalues, the authors establish the local exact controllability with boundary controls acting on one end or on two ends and internai controls acting on a part of equations in the system.
基金supported by the National Natural Science Foundation of China(Nos.11326159,11401421)the China Postdoctoral Science Foundation(No.2014M560287)the Shanxi Scholarship Council of China(No.2013-045)
文摘Under the internal dissipative condition, the Cauchy problem for inhomogeneous quasilinear hyperbolic systems with small initial data admits a unique global C1 solution, which exponentially decays to zero as t →＋∞, while if the coefficient matrix 19 of boundary conditions satisfies the boundary dissipative condition, the mixed initialboundary value problem with small initial data for quasilinear hyperbolic systems with nonlinear terms of at least second order admits a unique global C1 solution, which also exponentially decays to zero as t →＋∞. In this paper, under more general conditions, the authors investigate the combined effect of the internal dissipative condition and the boundary dissipative condition, and prove the global existence and exponential decay of the C1 solution to the mixed initial-boundary value problem for quasilinear hyperbolic systems with small initial data. This stability result is applied to a kind of models, and an example is given to show the possible exponential instability if the corresponding conditions are not satisfied.
基金supported by the National Natural Science Foundation of China(Nos.11201119,11471099)the International Cultivation of Henan Advanced Talents and the Research Foundation of Henan University(No.yqpy20140043)
文摘Let B R^n be the unit ball centered at the origin. The authors consider the following biharmonic equation:{?~2u = λ(1 + u)~p in B,u =?u/?ν= 0 on ?B, where p >n+4/ n-4and ν is the outward unit normal vector. It is well-known that there exists a λ*> 0 such that the biharmonic equation has a solution for λ∈ (0, λ*) and has a unique weak solution u*with parameter λ = λ*, called the extremal solution. It is proved that u* is singular when n ≥ 13 for p large enough and satisfies u*≤ r^(-4/ (p-1)) - 1 on the unit ball, which actually solve a part of the open problem left in [D`avila, J., Flores, I., Guerra, I., Multiplicity of solutions for a fourth order equation with power-type nonlinearity, Math. Ann., 348(1), 2009, 143–193] .
