图像分割是计算机医疗辅助诊断中关键技术。文中为内窥镜辅助诊断系统提供较好的图像分割技术,使之应用于内窥镜图像的自动分割,进而进行病症的识别、筛选。再对无需重新初始化的CV模型(CV Model Without Re-initialization,CVWR)在医...图像分割是计算机医疗辅助诊断中关键技术。文中为内窥镜辅助诊断系统提供较好的图像分割技术,使之应用于内窥镜图像的自动分割,进而进行病症的识别、筛选。再对无需重新初始化的CV模型(CV Model Without Re-initialization,CVWR)在医学图像分割中的应用进行了研究,并进一步实现了对医学视频流的的逐帧分割,方便了医生诊断。最后总结了CVWR在实际医学图像分割中的优缺点。展开更多
With simultaneous observed sea surface temperature anomaly （SSTA）, the difference between NCEP/NCAR 925hPa reanalysis wind stress anomaly （NCEPWSA） and FSU wind stress anomaly （FSUWSA） is analyzed, and the predi...With simultaneous observed sea surface temperature anomaly （SSTA）, the difference between NCEP/NCAR 925hPa reanalysis wind stress anomaly （NCEPWSA） and FSU wind stress anomaly （FSUWSA） is analyzed, and the prediction abilities of Zebiak-Cane coupled ocean-atmosphere model （ZC coupled model） with NCEPWSA and FSUWSA serving respectively as initialization wind are compared. The results are as follows. The distribution feature of NCEPWSA matches better with that of the observed SSTA than counterpart of FSUWSA both in 1980s and in 1990s; The ZC ocean model has a better skill under the forcing of NCEPWSA than that of FSUWSA, especially in 1990s. Meanwhile, the forecast abilities of the ZC coupled model in 1990s as well as in 1980s have been improved employing NCEPWSA as initialization wind instead of FSUWSA. Particularly, it succeeded in predicting 1997/1998 E1 Nino 6 to 8 months ahead, further analysis shows that on the antecedent and onset stages of the 1997/1998 E1 Nino event, the horizontal cold and warm distribution characteristics of the simulated SSTA from ZC ocean model, with NCEPWSA forcing compared to FSUWSA forcing, match better with counterparts of the corresponding observed SSTA, whereby providing better predication initialization conditions for ZC coupled model, which, in turn, is favorable to improve the forecast ability of the coupled model.展开更多
1 INTRODUCTION The initial state of the atmosphere is one of the key factors that affect the result of NWP. With the development of increasingly finer NWP, the quality of initial atmospheric state has been drawing mor...1 INTRODUCTION The initial state of the atmosphere is one of the key factors that affect the result of NWP. With the development of increasingly finer NWP, the quality of initial atmospheric state has been drawing more and more attention . GRAPES 3D- Var （Global and Regional Assimilation and Prediction Enhanced System , a three-dimensional variational data assimilation subsystem developed by the Chinese Academy of Atmospheric Sciences, makes a solution to the issue of NWP data vacancy in China. Owing to it, quantitative application of satellite and radar data in NWP has significant breakthroughs. With the assimilation system of GRAPES 3D-Var and GRAPES regional mesoscale model, this work compares a control and assimilation experiment with regard to a cold air surge affecting south China in late December 2004 and analyzes the sensitivity of mesoscale model forecast on initial values and the effect of initialization on the improvement of forecasting capabilities.展开更多
In this paper, some corrections was made to the assumption that the forcing is quasi-static, which is the basis of the nonlinear diabatic initialization scheme adopted by a global model T106L19. Thus the tidal signal ...In this paper, some corrections was made to the assumption that the forcing is quasi-static, which is the basis of the nonlinear diabatic initialization scheme adopted by a global model T106L19. Thus the tidal signal is expressed and excluded from the initialization scheme. It shows that the new scheme captures the semi-diurnal pressure variation and is much closer to the uninitialized field. Compared with the standard initialization scheme, both the anomaly correlation coefficients and RMS of 500 hPa geopotential height simulated under the new scheme have improved significantly.展开更多
Taking the decoherence effect into account, the entanglement evolution of a two-qubit anisotropic Heisenberg XYZ chain in the presence of inhomogeneous magnetic field is investigated. The time evolution of concurrence...Taking the decoherence effect into account, the entanglement evolution of a two-qubit anisotropic Heisenberg XYZ chain in the presence of inhomogeneous magnetic field is investigated. The time evolution of concurrence is studied for the initial state cos θ｜01） ＋ sin θ｜10） at zero temperature. The influences of inhomogeneous magnetic field, anisotropic parameter and decoherence on entanglement dynamic are addressed in detail, and a concurrence formula of the steady state is found. It is shown that the entanglement sudden death （ESD） and entanglement sudden birth （ESB） appear with the decoherence effect, and the stable concurrence depends on the uniform magnetic field B, anisotropic parameter △ and environment coupling strength γ, which is independent of different initial states and nonuniform magnetic field b.展开更多
The key technologies of precision blasting were put forward based on the characteristics of urban via- duct blasting demolition in complicated surroundings. Initial bending instability mechanics model of reinforcing s...The key technologies of precision blasting were put forward based on the characteristics of urban via- duct blasting demolition in complicated surroundings. Initial bending instability mechanics model of reinforcing steel bar frame of blasting fragmented pier and sequenced collapsed dynamic model were established for quanti- tative blasting design. Technologies of water pressure blasting were applied in multi-cell box girder fragmenta- tion. The detonating network of non-electric duplication crossover was adopted for the safety and reliability of ultra-long delay. The rationality of blasting scheme and parameters were validated by physical model test. Harm- ful effects were forecasted and controlled by integrated protective technologies. Specialization, cooperation, pre- cision, execution （SCPE） project management method was put forward for precision management. The key tech- nologies of precision demolition blasting can provide reference for similar proiects.展开更多
Adjoint-free calculation method is proposed to compute conditional nonlinear optimal perturbations(CNOP) combined with initial perturbations and model parameter perturbations. The new approach avoids the use of adjoin...Adjoint-free calculation method is proposed to compute conditional nonlinear optimal perturbations(CNOP) combined with initial perturbations and model parameter perturbations. The new approach avoids the use of adjoint technique in the optimization process. CNOPs respectively generated by ensemble-based and adjoint-based methods are compared based on a simple theoretical model.展开更多
In this paper,we study two different nonlinear interpolating paths in adiabatic evolution algorithms for solving a particular class of quantum search problems where both the initial and final Hamiltonian are one-dimen...In this paper,we study two different nonlinear interpolating paths in adiabatic evolution algorithms for solving a particular class of quantum search problems where both the initial and final Hamiltonian are one-dimensional projector Hamiltonians on the corresponding ground state.If the overlap between the initial state and final state of the quantum system is not equal to zero,both of these models can provide a constant time speedup over the usual adiabatic algorithms by increasing some another corresponding "complexity".But when the initial state has a zero overlap with the solution state in the problem,the second model leads to an infinite time complexity of the algorithm for whatever interpolating functions being applied while the first one can still provide a constant running time.However,inspired by a related reference,a variant of the first model can be constructed which also fails for the problem when the overlap is exactly equal to zero if we want to make up the "intrinsic" fault of the second model - an increase in energy.Two concrete theorems are given to serve as explanations why neither of these two models can improve the usual adiabatic evolution algorithms for the phenomenon above.These just tell us what should be noted when using certain nonlinear evolution paths in adiabatic quantum algorithms for some special kind of problems.展开更多
文摘图像分割是计算机医疗辅助诊断中关键技术。文中为内窥镜辅助诊断系统提供较好的图像分割技术,使之应用于内窥镜图像的自动分割,进而进行病症的识别、筛选。再对无需重新初始化的CV模型(CV Model Without Re-initialization,CVWR)在医学图像分割中的应用进行了研究,并进一步实现了对医学视频流的的逐帧分割,方便了医生诊断。最后总结了CVWR在实际医学图像分割中的优缺点。
基金Natural Science Foundation of China (40275016)Science and Technology DevelopmentProject for the Shanghai Meteorological Bureau (0301)
文摘With simultaneous observed sea surface temperature anomaly （SSTA）, the difference between NCEP/NCAR 925hPa reanalysis wind stress anomaly （NCEPWSA） and FSU wind stress anomaly （FSUWSA） is analyzed, and the prediction abilities of Zebiak-Cane coupled ocean-atmosphere model （ZC coupled model） with NCEPWSA and FSUWSA serving respectively as initialization wind are compared. The results are as follows. The distribution feature of NCEPWSA matches better with that of the observed SSTA than counterpart of FSUWSA both in 1980s and in 1990s; The ZC ocean model has a better skill under the forcing of NCEPWSA than that of FSUWSA, especially in 1990s. Meanwhile, the forecast abilities of the ZC coupled model in 1990s as well as in 1980s have been improved employing NCEPWSA as initialization wind instead of FSUWSA. Particularly, it succeeded in predicting 1997/1998 E1 Nino 6 to 8 months ahead, further analysis shows that on the antecedent and onset stages of the 1997/1998 E1 Nino event, the horizontal cold and warm distribution characteristics of the simulated SSTA from ZC ocean model, with NCEPWSA forcing compared to FSUWSA forcing, match better with counterparts of the corresponding observed SSTA, whereby providing better predication initialization conditions for ZC coupled model, which, in turn, is favorable to improve the forecast ability of the coupled model.
基金Key Scientific Research Project of Guangdong (2004B32601002)Promotion Project forLatest Meteorological Technology (CMATG2005M17)+1 种基金National Project No.973 (2004CB18307)"Research onAssimilation Techniques for Tropics based on Modern Observation Technologies"
文摘1 INTRODUCTION The initial state of the atmosphere is one of the key factors that affect the result of NWP. With the development of increasingly finer NWP, the quality of initial atmospheric state has been drawing more and more attention . GRAPES 3D- Var （Global and Regional Assimilation and Prediction Enhanced System , a three-dimensional variational data assimilation subsystem developed by the Chinese Academy of Atmospheric Sciences, makes a solution to the issue of NWP data vacancy in China. Owing to it, quantitative application of satellite and radar data in NWP has significant breakthroughs. With the assimilation system of GRAPES 3D-Var and GRAPES regional mesoscale model, this work compares a control and assimilation experiment with regard to a cold air surge affecting south China in late December 2004 and analyzes the sensitivity of mesoscale model forecast on initial values and the effect of initialization on the improvement of forecasting capabilities.
基金Scientific research project for the 10th five-year economic development period(2001BA607B02) a project from the Chinese Academy of Meteorological Sciences (7046/2001-9Y-2)
文摘In this paper, some corrections was made to the assumption that the forcing is quasi-static, which is the basis of the nonlinear diabatic initialization scheme adopted by a global model T106L19. Thus the tidal signal is expressed and excluded from the initialization scheme. It shows that the new scheme captures the semi-diurnal pressure variation and is much closer to the uninitialized field. Compared with the standard initialization scheme, both the anomaly correlation coefficients and RMS of 500 hPa geopotential height simulated under the new scheme have improved significantly.
基金Supported by National Natural Science Foundation of China under Grant No.10904033Natural Science Foundation of Hubei Province under Grant No.2009CDA145+1 种基金Educational Commission of Hubei Province under Grant No.D20092204Natural Science Foundation of Hubei Normal University under Grant No.2007D21
文摘Taking the decoherence effect into account, the entanglement evolution of a two-qubit anisotropic Heisenberg XYZ chain in the presence of inhomogeneous magnetic field is investigated. The time evolution of concurrence is studied for the initial state cos θ｜01） ＋ sin θ｜10） at zero temperature. The influences of inhomogeneous magnetic field, anisotropic parameter and decoherence on entanglement dynamic are addressed in detail, and a concurrence formula of the steady state is found. It is shown that the entanglement sudden death （ESD） and entanglement sudden birth （ESB） appear with the decoherence effect, and the stable concurrence depends on the uniform magnetic field B, anisotropic parameter △ and environment coupling strength γ, which is independent of different initial states and nonuniform magnetic field b.
文摘The key technologies of precision blasting were put forward based on the characteristics of urban via- duct blasting demolition in complicated surroundings. Initial bending instability mechanics model of reinforcing steel bar frame of blasting fragmented pier and sequenced collapsed dynamic model were established for quanti- tative blasting design. Technologies of water pressure blasting were applied in multi-cell box girder fragmenta- tion. The detonating network of non-electric duplication crossover was adopted for the safety and reliability of ultra-long delay. The rationality of blasting scheme and parameters were validated by physical model test. Harm- ful effects were forecasted and controlled by integrated protective technologies. Specialization, cooperation, pre- cision, execution （SCPE） project management method was put forward for precision management. The key tech- nologies of precision demolition blasting can provide reference for similar proiects.
基金supported by National Natural Science Foundation of China(Grant No.11201265)Shandong Natural Science Foundation(Grant No.ZR2012AM003)China Postdoctoral Science Foundation(Grant No.20110490564)
文摘Adjoint-free calculation method is proposed to compute conditional nonlinear optimal perturbations(CNOP) combined with initial perturbations and model parameter perturbations. The new approach avoids the use of adjoint technique in the optimization process. CNOPs respectively generated by ensemble-based and adjoint-based methods are compared based on a simple theoretical model.
基金Supported by the National Natural Science Foundation of China under Grant No. 61173050
文摘In this paper,we study two different nonlinear interpolating paths in adiabatic evolution algorithms for solving a particular class of quantum search problems where both the initial and final Hamiltonian are one-dimensional projector Hamiltonians on the corresponding ground state.If the overlap between the initial state and final state of the quantum system is not equal to zero,both of these models can provide a constant time speedup over the usual adiabatic algorithms by increasing some another corresponding "complexity".But when the initial state has a zero overlap with the solution state in the problem,the second model leads to an infinite time complexity of the algorithm for whatever interpolating functions being applied while the first one can still provide a constant running time.However,inspired by a related reference,a variant of the first model can be constructed which also fails for the problem when the overlap is exactly equal to zero if we want to make up the "intrinsic" fault of the second model - an increase in energy.Two concrete theorems are given to serve as explanations why neither of these two models can improve the usual adiabatic evolution algorithms for the phenomenon above.These just tell us what should be noted when using certain nonlinear evolution paths in adiabatic quantum algorithms for some special kind of problems.
