Stamping process,which is widely used in automobile,aerospace,machine-building industries,and etc.,is a creative process needing time and experiences.The lead time is mainly spent on stamping die design and manufactur...Stamping process,which is widely used in automobile,aerospace,machine-building industries,and etc.,is a creative process needing time and experiences.The lead time is mainly spent on stamping die design and manufacturing.As the ba- sis of die design,process design is a non-linearity and creative process,which can be solved by using the fuzzy synthetic evaluation. In this paper,the potential o f fuzzy synthetic evaluation for dealing with stamping process design was explored.The influencing factor set,factor weight set,evaluation set,single factor fuzzy evaluation matrix,and fuzzy synthetic evaluation scheme were studied.Finally,the washer part,considering forming equipment,part dimensions and other factors,was selected to testify the evaluation process.展开更多
This paper uses a Modified Soil-Plant-Atmosphere Scheme (MSPAS) to study the interaction between land surface and atmospheric boundary layer processes. The scheme is composed of two main parts: atmospheric boundary la...This paper uses a Modified Soil-Plant-Atmosphere Scheme (MSPAS) to study the interaction between land surface and atmospheric boundary layer processes. The scheme is composed of two main parts: atmospheric boundary layer processes and land surface processes. Compared with SiB and BATS, which are famous for their detailed parameterizations of physical variables, this simplified model is more convenient and saves much more computation time. Though simple, the feasibility of the model is well proved in this paper. The numerical simulation results from MSPAS show good agreement with reality. The scheme is used to obtain reasonable simulations for diurnal variations of heat balance, potential temperature of boundary layer, and wind field, and spatial distributions of temperature, specific humidity, vertical velocity, turbulence kinetic energy, and turbulence exchange coefficient over desert and oasis. In addition, MSPAS is used to simulate the interaction between desert and oasis at night, and again it obtains reasonable results. This indicates that MSPAS can be used to study the interaction between land surface processes and the atmospheric boundary layer over various underlying surfaces and can be extended for regional climate and numerical weather prediction study.展开更多
In this paper, we propose numerical schemes for stochastic differential equations driven by G-Lévy process under the G-expectation framework. By using G-Itôformula and G-expectation property, we propose ...In this paper, we propose numerical schemes for stochastic differential equations driven by G-Lévy process under the G-expectation framework. By using G-Itôformula and G-expectation property, we propose Euler scheme and Milstein scheme which have order-1.0 convergence rate. And two numerical experiments including Ornstein-Uhlenbeck and Black-Scholes cases are given.展开更多
With the increasing trend of heavy crudes supply with deteriorated quality and demand for clean fuels, deep processing of residuum, in particular the processing of low-grade resid, has become the main source for enhan...With the increasing trend of heavy crudes supply with deteriorated quality and demand for clean fuels, deep processing of residuum, in particular the processing of low-grade resid, has become the main source for enhancing economic benefits of oil refiners. This article has discussed the technol- ogy for processing of different resids and the advantages and disadvantages of the combination pro- cesses for resid processing, while pinpointing the directions for development and application of tech- nologies for resid processing in China.展开更多
Wavelet transform is an ideal way for edge detection because of its multi-scale property, localization both in time and frequency domain, sensitivity to the abrupt change of signals, and so on. An improved algorithm f...Wavelet transform is an ideal way for edge detection because of its multi-scale property, localization both in time and frequency domain, sensitivity to the abrupt change of signals, and so on. An improved algorithm for image edge detection based on Lifting Scheme is proposed in this paper. The simulation results show that our improved method can better reflect edge information of images.展开更多
In flexible job-shop batch scheduling problem, the optimal lot-size of different process is not always the same because of different processing time and set-up time. Even for the same process of the same workpiece, th...In flexible job-shop batch scheduling problem, the optimal lot-size of different process is not always the same because of different processing time and set-up time. Even for the same process of the same workpiece, the choice of machine also affects the optimal lot-size. In addition, different choices of lot-size between the constrained processes will impact the manufacture efficiency. Considering that each process has its own appropriate lot-size, we put forward the concept of scheduling with lot-splitting based on process and set up the scheduling model of lot-splitting to critical path process as the core. The model could update the set of batch process and machine selection strategy dynamically to determine processing route and arrange proper lot-size for different processes, to achieve the purpose of optimizing the makespan and reducing the processing batches effectively. The experiment results show that, comparing with lot-splitting scheduling scheme based on workpiece, this model optimizes the makespan and improves the utilization efficiency of the machine. It also greatly decreases the machined batches （42%） and reduces the complexity of shop scheduling production management.展开更多
In this paper we propose a numerical method to estimate the fractal dimension of stationary Gaussian stochastic processes using the random Euler numerical scheme and based on an analytical formulation of the fractal d...In this paper we propose a numerical method to estimate the fractal dimension of stationary Gaussian stochastic processes using the random Euler numerical scheme and based on an analytical formulation of the fractal dimension for filtered stochastic signals. The discretization of continuous time processes through this random scheme allows us to find, numerically, the expected value, variance and correlation functions at any point of time. This alternative method for estimating the fractal dimension is easy to implement and requires no sophisticated routines. We use simulated data sets for stationary processes of the type Random Ornstein Uhlenbeck to graphically illustrate the results and compare them with those obtained whit the box counting theorem.展开更多
文摘Stamping process,which is widely used in automobile,aerospace,machine-building industries,and etc.,is a creative process needing time and experiences.The lead time is mainly spent on stamping die design and manufacturing.As the ba- sis of die design,process design is a non-linearity and creative process,which can be solved by using the fuzzy synthetic evaluation. In this paper,the potential o f fuzzy synthetic evaluation for dealing with stamping process design was explored.The influencing factor set,factor weight set,evaluation set,single factor fuzzy evaluation matrix,and fuzzy synthetic evaluation scheme were studied.Finally,the washer part,considering forming equipment,part dimensions and other factors,was selected to testify the evaluation process.
基金supported by the National Natural Science Foundation of China (Grant No.40275004)the State Key Laboratory of Atmosphere Physics and Chemistry,and the City University of Hong Kong(Grant No.8780046)the City University of Hong Kong Strategic Research(Grant No.7001038)
文摘This paper uses a Modified Soil-Plant-Atmosphere Scheme (MSPAS) to study the interaction between land surface and atmospheric boundary layer processes. The scheme is composed of two main parts: atmospheric boundary layer processes and land surface processes. Compared with SiB and BATS, which are famous for their detailed parameterizations of physical variables, this simplified model is more convenient and saves much more computation time. Though simple, the feasibility of the model is well proved in this paper. The numerical simulation results from MSPAS show good agreement with reality. The scheme is used to obtain reasonable simulations for diurnal variations of heat balance, potential temperature of boundary layer, and wind field, and spatial distributions of temperature, specific humidity, vertical velocity, turbulence kinetic energy, and turbulence exchange coefficient over desert and oasis. In addition, MSPAS is used to simulate the interaction between desert and oasis at night, and again it obtains reasonable results. This indicates that MSPAS can be used to study the interaction between land surface processes and the atmospheric boundary layer over various underlying surfaces and can be extended for regional climate and numerical weather prediction study.
文摘In this paper, we propose numerical schemes for stochastic differential equations driven by G-Lévy process under the G-expectation framework. By using G-Itôformula and G-expectation property, we propose Euler scheme and Milstein scheme which have order-1.0 convergence rate. And two numerical experiments including Ornstein-Uhlenbeck and Black-Scholes cases are given.
文摘With the increasing trend of heavy crudes supply with deteriorated quality and demand for clean fuels, deep processing of residuum, in particular the processing of low-grade resid, has become the main source for enhancing economic benefits of oil refiners. This article has discussed the technol- ogy for processing of different resids and the advantages and disadvantages of the combination pro- cesses for resid processing, while pinpointing the directions for development and application of tech- nologies for resid processing in China.
文摘Wavelet transform is an ideal way for edge detection because of its multi-scale property, localization both in time and frequency domain, sensitivity to the abrupt change of signals, and so on. An improved algorithm for image edge detection based on Lifting Scheme is proposed in this paper. The simulation results show that our improved method can better reflect edge information of images.
基金Supported by National Key Technology R&D Program(No.2013BAJ06B)
文摘In flexible job-shop batch scheduling problem, the optimal lot-size of different process is not always the same because of different processing time and set-up time. Even for the same process of the same workpiece, the choice of machine also affects the optimal lot-size. In addition, different choices of lot-size between the constrained processes will impact the manufacture efficiency. Considering that each process has its own appropriate lot-size, we put forward the concept of scheduling with lot-splitting based on process and set up the scheduling model of lot-splitting to critical path process as the core. The model could update the set of batch process and machine selection strategy dynamically to determine processing route and arrange proper lot-size for different processes, to achieve the purpose of optimizing the makespan and reducing the processing batches effectively. The experiment results show that, comparing with lot-splitting scheduling scheme based on workpiece, this model optimizes the makespan and improves the utilization efficiency of the machine. It also greatly decreases the machined batches （42%） and reduces the complexity of shop scheduling production management.
文摘In this paper we propose a numerical method to estimate the fractal dimension of stationary Gaussian stochastic processes using the random Euler numerical scheme and based on an analytical formulation of the fractal dimension for filtered stochastic signals. The discretization of continuous time processes through this random scheme allows us to find, numerically, the expected value, variance and correlation functions at any point of time. This alternative method for estimating the fractal dimension is easy to implement and requires no sophisticated routines. We use simulated data sets for stationary processes of the type Random Ornstein Uhlenbeck to graphically illustrate the results and compare them with those obtained whit the box counting theorem.
