This paper introduces a novel automatic physical synthesis methodology for analog circuits based on the signal-flow analysis.Circuit analysis sub-system adopts the newly advanced methodology,circuit topology analysis,...This paper introduces a novel automatic physical synthesis methodology for analog circuits based on the signal-flow analysis.Circuit analysis sub-system adopts the newly advanced methodology,circuit topology analysis,and circuit sensitivity analysis to generate layout constraints and control performance degradations.Considering the heuristic information about signal-flow,complexity of the methodology is less than the pure performance-driven methodology.And then these constraints are implemented in device generation,placement,and routing sub-systems separately,which makes the different constraints be satisfied at most easily implemented stages.Excellent circuit performance obtained by the methodology is demonstrated by practical circuit examples.展开更多
Cellular Automata(CA) is widely used for the simulation of land use changes. This study applied a vector-based CA model to simulate land use change in order to minimize or eliminate the scale sensitivity in traditiona...Cellular Automata(CA) is widely used for the simulation of land use changes. This study applied a vector-based CA model to simulate land use change in order to minimize or eliminate the scale sensitivity in traditional raster-based CA model. The cells of vector-based CA model are presented according to the shapes and attributes of geographic entities, and the transition rules of vector-based CA model are improved by taking spatial variables of the study area into consideration. The vector-based CA model is applied to simulate land use changes in downtown of Qidong City, Jiangsu Province, China and its validation is confirmed by the methods of visual assessment and spatial accuracy. The simulation result of vector-based CA model reveals that nearly 75% of newly increased urban cells are located in the northwest and southwest parts of the study area from 2002 to 2007, which is in consistent with real land use map. In addition, the simulation results of the vector-based and raster-based CA models are compared to real land use data and their spatial accuracies are found to be 84.0% and 81.9%, respectively. In conclusion, results from this study indicate that the vector-based CA model is a practical and applicable method for the simulation of urbanization processes.展开更多
Recirculation is prohibited in many coal mining countries because of the fear that the re-use of return air would allow the build-up of air contaminants at the workings. The incorrect design and location of a booster ...Recirculation is prohibited in many coal mining countries because of the fear that the re-use of return air would allow the build-up of air contaminants at the workings. The incorrect design and location of a booster fan in any ventilation network can create unsafe condition due to recirculation. The current approach to investigating recirculation using simulation software requires manual effort which becomes tedious in a complex and a large network. An algorithm-based C++ program was designed to detect the recirculation in a booster fan ventilation networks. This program needed an input file prepared from output file generated by any ventilation simulator. This program created an output file for recirculation. This program demonstrated the strong capability to detect the recirculation in a sample network and a coal mine ventilation network. The outcomes of this program were documented in this paper.展开更多
A new artificial immune algorithm （AIA） simulating the biological immune network system with selfadjustment function is proposed in this paper. AIA is based on the modified immune network model in which two methods ...A new artificial immune algorithm （AIA） simulating the biological immune network system with selfadjustment function is proposed in this paper. AIA is based on the modified immune network model in which two methods of affinity measure evaluated are used, controlling the antibody diversity and the speed of convergence separately. The model proposed focuses on a systemic view of the immune system and takes into account cell-cell interactions denoted by antibody affinity. The antibody concentration defined in the immune network model is responsible directly for its activity in the immune system. The model introduces not only a term describing the network dynamics, but also proposes an independent term to simulate the dynamics of the antigen population. The antibodies＇ evolutionary processes are controlled in the algorithms by utilizing the basic properties of the immune network. Computational amount and effect is a pair of contradictions. In terms of this problem, the AIA regulating the parameters easily attains a compromise between them. At the same time, AIA can prevent premature convergence at the cost of a heavy computational amount （the iterative times）. Simulation illustrates that AIA is adapted to solve optimization problems, emphasizing muhimodal optimization.展开更多
We present a theoretical study of the reaction of the hydroxyl radical with ethene using electronic structure calculations and direct-dynamics simulations. High-accuracy electronic structure calculations at the CCSD（...We present a theoretical study of the reaction of the hydroxyl radical with ethene using electronic structure calculations and direct-dynamics simulations. High-accuracy electronic structure calculations at the CCSD（T）/aug-cc-pVTZ//MP2/aug-ce-pVDZ level have been carried out to characterize the representative regions of the potential energy surface of various reaction pathways, including OH-addition and H-abstraction. These ab initio calculations have been employed to derive an improved set of parameters for the MSINDO semiempirieal Hamiltonian specific to the OH＋C2H4 reaction. The specific-reaction-parameter Hamilto- nian captures the ab initio data accurately, and has been used to perform direct quasiclassica] trajectory simulations of the OH＋C2H4 reaction at collision energies in the range of 2-10 kcal/mol. The calculated cross sections reveal that the OH-addition reaction domi- nates at all energies over H-abstraction. In addition, the excitation function of addition is reminiscent of a barrierless capture process, while that for abstraction corresponds to an activated one, and these trends can be connected to the transition-state energies of both reactions. We note that the development of an accurate semiempirical Hamiltonian for the OH＋C2H4 reaction in this work required the inclusion of empirical dispersion corrections, which will be important in future applications for which long-range intermoleeular attraction becomes significant.展开更多
文摘This paper introduces a novel automatic physical synthesis methodology for analog circuits based on the signal-flow analysis.Circuit analysis sub-system adopts the newly advanced methodology,circuit topology analysis,and circuit sensitivity analysis to generate layout constraints and control performance degradations.Considering the heuristic information about signal-flow,complexity of the methodology is less than the pure performance-driven methodology.And then these constraints are implemented in device generation,placement,and routing sub-systems separately,which makes the different constraints be satisfied at most easily implemented stages.Excellent circuit performance obtained by the methodology is demonstrated by practical circuit examples.
基金Under the auspices of National Natural Science Foundation of China(No.41101349)Surveying and Mapping Scientific Research Projects of Jiangsu Province(No.JSCHKY201304)+1 种基金Program of Natural Science Research of Jiangsu Higher Education Institutions of China(No.13KJB420003)Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘Cellular Automata(CA) is widely used for the simulation of land use changes. This study applied a vector-based CA model to simulate land use change in order to minimize or eliminate the scale sensitivity in traditional raster-based CA model. The cells of vector-based CA model are presented according to the shapes and attributes of geographic entities, and the transition rules of vector-based CA model are improved by taking spatial variables of the study area into consideration. The vector-based CA model is applied to simulate land use changes in downtown of Qidong City, Jiangsu Province, China and its validation is confirmed by the methods of visual assessment and spatial accuracy. The simulation result of vector-based CA model reveals that nearly 75% of newly increased urban cells are located in the northwest and southwest parts of the study area from 2002 to 2007, which is in consistent with real land use map. In addition, the simulation results of the vector-based and raster-based CA models are compared to real land use data and their spatial accuracies are found to be 84.0% and 81.9%, respectively. In conclusion, results from this study indicate that the vector-based CA model is a practical and applicable method for the simulation of urbanization processes.
基金the National Institute for Occupational Safety and Health of USA for providing financial support for this project
文摘Recirculation is prohibited in many coal mining countries because of the fear that the re-use of return air would allow the build-up of air contaminants at the workings. The incorrect design and location of a booster fan in any ventilation network can create unsafe condition due to recirculation. The current approach to investigating recirculation using simulation software requires manual effort which becomes tedious in a complex and a large network. An algorithm-based C++ program was designed to detect the recirculation in a booster fan ventilation networks. This program needed an input file prepared from output file generated by any ventilation simulator. This program created an output file for recirculation. This program demonstrated the strong capability to detect the recirculation in a sample network and a coal mine ventilation network. The outcomes of this program were documented in this paper.
文摘A new artificial immune algorithm （AIA） simulating the biological immune network system with selfadjustment function is proposed in this paper. AIA is based on the modified immune network model in which two methods of affinity measure evaluated are used, controlling the antibody diversity and the speed of convergence separately. The model proposed focuses on a systemic view of the immune system and takes into account cell-cell interactions denoted by antibody affinity. The antibody concentration defined in the immune network model is responsible directly for its activity in the immune system. The model introduces not only a term describing the network dynamics, but also proposes an independent term to simulate the dynamics of the antigen population. The antibodies＇ evolutionary processes are controlled in the algorithms by utilizing the basic properties of the immune network. Computational amount and effect is a pair of contradictions. In terms of this problem, the AIA regulating the parameters easily attains a compromise between them. At the same time, AIA can prevent premature convergence at the cost of a heavy computational amount （the iterative times）. Simulation illustrates that AIA is adapted to solve optimization problems, emphasizing muhimodal optimization.
文摘We present a theoretical study of the reaction of the hydroxyl radical with ethene using electronic structure calculations and direct-dynamics simulations. High-accuracy electronic structure calculations at the CCSD（T）/aug-cc-pVTZ//MP2/aug-ce-pVDZ level have been carried out to characterize the representative regions of the potential energy surface of various reaction pathways, including OH-addition and H-abstraction. These ab initio calculations have been employed to derive an improved set of parameters for the MSINDO semiempirieal Hamiltonian specific to the OH＋C2H4 reaction. The specific-reaction-parameter Hamilto- nian captures the ab initio data accurately, and has been used to perform direct quasiclassica] trajectory simulations of the OH＋C2H4 reaction at collision energies in the range of 2-10 kcal/mol. The calculated cross sections reveal that the OH-addition reaction domi- nates at all energies over H-abstraction. In addition, the excitation function of addition is reminiscent of a barrierless capture process, while that for abstraction corresponds to an activated one, and these trends can be connected to the transition-state energies of both reactions. We note that the development of an accurate semiempirical Hamiltonian for the OH＋C2H4 reaction in this work required the inclusion of empirical dispersion corrections, which will be important in future applications for which long-range intermoleeular attraction becomes significant.
