Aim To provide technical parameters for development of quartz gyro. Methods Theory of elastic beam was applied to piezoelectric beam. Based on the concept of equivalent volume force and energy conservation, the f...Aim To provide technical parameters for development of quartz gyro. Methods Theory of elastic beam was applied to piezoelectric beam. Based on the concept of equivalent volume force and energy conservation, the formula of electrode location efficiency was derived. And the electric system was compared with the dynamic one according to the principle of equivalent circuit for piezoelectric crystal, and the general formulae of the parameters for the equivalent circuit, R n L n C n , were derived. Results and Conclusion Optimum electrode location is chosen, and the derived equivalent circuit parameters are the theoretical base of the circuit design for quartz gyro.展开更多
A two-level layout optimization strategy is proposed in this paper for large-scale composite wing structures. Design requirements are adjusted at the system level according to structural deformation, while the layout ...A two-level layout optimization strategy is proposed in this paper for large-scale composite wing structures. Design requirements are adjusted at the system level according to structural deformation, while the layout is optimized at the subsystem level to satisfy the constraints from system level. The approaching degrees of various failure critical loads in wing panels are employed to gauge the structure’s carrying efficiency. By optimizing the efficiency as an objective, the continuity of the problem could be guaranteed. Stiffened wing panels are modeled by the equivalent orthotropic plates, and the global buckling load is predicted by energy method. The nonlinear effect of stringers’ support elasticity on skin local buckle resistance is investigated and approximated by neural network （NN） surrogate model. These failure predictions are based on analytical solutions, which could effectively save calculation resources. Finally, the integral optimization of a large-scale wing structure is completed as an example. The result fulfills design requirements and shows the feasibility of this method.展开更多
The concept of hybrid ships has gained significant attention in recent years,as they offer an effective means of enhancing energy utilization and reducing environmental pollution.However,the navigational environments ...The concept of hybrid ships has gained significant attention in recent years,as they offer an effective means of enhancing energy utilization and reducing environmental pollution.However,the navigational environments of ships are often subject to changes,which in turn affect their energy efficiency in a complex manner.It is therefore evident that enhancing the energy efficiency of hybrid ships is a worthwhile goal.In this study,we take a diesel-electric hybrid ship navigating in inland waterways as the research object,and propose a hierarchical optimization method for ship energy efficiency.The upper-layer control establishes a predictive model for propulsion motor speed and fuel consumption through multivariate time series predictions,and employs the model predictive control(MPC)method to optimize the propulsion motor speed.The lower-layer control utilizes an equivalent fuel consumption minimization method,which is based on improving the equivalence factor.This involves combining the variation of the supercapacitor’s state of charge(SOC)with the propulsion motor speed obtained from the MPC optimization in the upper-layer control.Furthermore,a proportional integral(PI)controller is used to adjust the equivalence factor,in order to adapt the equivalent fuel consumption minimization method to the working conditions.Our results demonstrate that the proposed hierarchical optimization method can reduce the energy efficiency operating indicator(EEOI)by approximately 11.54%and the fuel consumption by approximately 9.47%in comparison to the pre-optimization scenario.展开更多
The poor energy proportionality of server is seen as the principal source for low energy efficiency of modern data centers. We find that different resource configurations of an application lead to similar performance,...The poor energy proportionality of server is seen as the principal source for low energy efficiency of modern data centers. We find that different resource configurations of an application lead to similar performance, but have distinct energy consumption. We call this phenomenon as ＂performance-equivalent resource configurations （PERC）＂, and its performance range is called equivalent region （ER）. Based on PERC, one basic idea for improving energy efficiency is to select the most efficient configuration from PERC for each application. However, it cannot support every application to obtain optimal solution when thousands of applications are run simultaneously on resource-bounded servers. Here we propose a heuristic scheme, CPicker, based on genetic programming to improve energy efficiency of servers. To speed up convergence, CPicker initializes a high quality population by first choosing configurations from regions that have high energy variation. Experiments show that CPicker obtains above 17% energy efficiency improvement compared with the greedy approach, and less than 4% efficiency loss compared with the oracle case.展开更多
This article presents two designs,the Transaction Serial Format(TSF)and the Transaction Array Model(TAM).Together,they provide full,efficient,transaction serialization facilities for devices with limited onboard energ...This article presents two designs,the Transaction Serial Format(TSF)and the Transaction Array Model(TAM).Together,they provide full,efficient,transaction serialization facilities for devices with limited onboard energy,such as those in an Internet of Things(IoT)network.TSF provides a compact,non-parsed,format that requires minimal processing for transaction deserialization.TAM provides an internal data structure that needs minimal dynamic storage and directly uses the elements of TSF.The simple lexical units of TSF do not require parsing.The lexical units contain enough information to allocate the internal TAM data structure efficiently.TSF generality is equivalent to XML and JSON.TSF represents any XML document or JSON object without loss of information,including whitespace.The XML equivalence provides a foundation for the performance comparisons.A performance comparison of a C reference implementation of TSF and TAM to the popular Expat XML library,also written in C,shows that TSF reduces deserialization processor time by more than 80%.展开更多
文摘Aim To provide technical parameters for development of quartz gyro. Methods Theory of elastic beam was applied to piezoelectric beam. Based on the concept of equivalent volume force and energy conservation, the formula of electrode location efficiency was derived. And the electric system was compared with the dynamic one according to the principle of equivalent circuit for piezoelectric crystal, and the general formulae of the parameters for the equivalent circuit, R n L n C n , were derived. Results and Conclusion Optimum electrode location is chosen, and the derived equivalent circuit parameters are the theoretical base of the circuit design for quartz gyro.
基金National Natural Science Foundation of China （10872091）
文摘A two-level layout optimization strategy is proposed in this paper for large-scale composite wing structures. Design requirements are adjusted at the system level according to structural deformation, while the layout is optimized at the subsystem level to satisfy the constraints from system level. The approaching degrees of various failure critical loads in wing panels are employed to gauge the structure’s carrying efficiency. By optimizing the efficiency as an objective, the continuity of the problem could be guaranteed. Stiffened wing panels are modeled by the equivalent orthotropic plates, and the global buckling load is predicted by energy method. The nonlinear effect of stringers’ support elasticity on skin local buckle resistance is investigated and approximated by neural network （NN） surrogate model. These failure predictions are based on analytical solutions, which could effectively save calculation resources. Finally, the integral optimization of a large-scale wing structure is completed as an example. The result fulfills design requirements and shows the feasibility of this method.
基金supported by the National Natural Science Foundation of China(No.52571367)and the Commissions Project of China(No.CBG4N21).
文摘The concept of hybrid ships has gained significant attention in recent years,as they offer an effective means of enhancing energy utilization and reducing environmental pollution.However,the navigational environments of ships are often subject to changes,which in turn affect their energy efficiency in a complex manner.It is therefore evident that enhancing the energy efficiency of hybrid ships is a worthwhile goal.In this study,we take a diesel-electric hybrid ship navigating in inland waterways as the research object,and propose a hierarchical optimization method for ship energy efficiency.The upper-layer control establishes a predictive model for propulsion motor speed and fuel consumption through multivariate time series predictions,and employs the model predictive control(MPC)method to optimize the propulsion motor speed.The lower-layer control utilizes an equivalent fuel consumption minimization method,which is based on improving the equivalence factor.This involves combining the variation of the supercapacitor’s state of charge(SOC)with the propulsion motor speed obtained from the MPC optimization in the upper-layer control.Furthermore,a proportional integral(PI)controller is used to adjust the equivalence factor,in order to adapt the equivalent fuel consumption minimization method to the working conditions.Our results demonstrate that the proposed hierarchical optimization method can reduce the energy efficiency operating indicator(EEOI)by approximately 11.54%and the fuel consumption by approximately 9.47%in comparison to the pre-optimization scenario.
基金This work is supported by the National Natural Science Foundation of China under Grant Nos. 61572470, 61532017, 61522406, 61432017, 61376043, 61504153, and 61521092, and in part by Youth Innovation Promotion Association, Chinese Academy of Sciences （CAS）, under Grant No. Y404441000.
文摘The poor energy proportionality of server is seen as the principal source for low energy efficiency of modern data centers. We find that different resource configurations of an application lead to similar performance, but have distinct energy consumption. We call this phenomenon as ＂performance-equivalent resource configurations （PERC）＂, and its performance range is called equivalent region （ER）. Based on PERC, one basic idea for improving energy efficiency is to select the most efficient configuration from PERC for each application. However, it cannot support every application to obtain optimal solution when thousands of applications are run simultaneously on resource-bounded servers. Here we propose a heuristic scheme, CPicker, based on genetic programming to improve energy efficiency of servers. To speed up convergence, CPicker initializes a high quality population by first choosing configurations from regions that have high energy variation. Experiments show that CPicker obtains above 17% energy efficiency improvement compared with the greedy approach, and less than 4% efficiency loss compared with the oracle case.
文摘This article presents two designs,the Transaction Serial Format(TSF)and the Transaction Array Model(TAM).Together,they provide full,efficient,transaction serialization facilities for devices with limited onboard energy,such as those in an Internet of Things(IoT)network.TSF provides a compact,non-parsed,format that requires minimal processing for transaction deserialization.TAM provides an internal data structure that needs minimal dynamic storage and directly uses the elements of TSF.The simple lexical units of TSF do not require parsing.The lexical units contain enough information to allocate the internal TAM data structure efficiently.TSF generality is equivalent to XML and JSON.TSF represents any XML document or JSON object without loss of information,including whitespace.The XML equivalence provides a foundation for the performance comparisons.A performance comparison of a C reference implementation of TSF and TAM to the popular Expat XML library,also written in C,shows that TSF reduces deserialization processor time by more than 80%.
