Variable Cycle Engine(VCE)serves as the core system in achieving future advanced fighters with cross-generational performance and mission versatility.However,the resultant complex configuration and strong coupling of ...Variable Cycle Engine(VCE)serves as the core system in achieving future advanced fighters with cross-generational performance and mission versatility.However,the resultant complex configuration and strong coupling of control parameters present significant challenges in designing acceleration and deceleration control schedules.To thoroughly explore the performance potential of engine,a global integration design method for acceleration and deceleration control schedule based on inner and outer loop optimization is proposed.The outer loop optimization module employs Integrated Surrogate-Assisted Co-Differential Evolutionary(ISACDE)algorithm to optimize the variable geometry adjustment laws based on B-spline curve,and the inner loop optimization module adopts the fixed-state method to design the open-loop fuel–air ratio control schedules,which are aimed at minimizing the acceleration and deceleration time under multiple constraints.Simulation results demonstrate that the proposed global integration design method not only furthest shortens the acceleration and deceleration time,but also effectively safeguards the engine from overlimit.展开更多
This paper explains the goal conflict between schedule and quality in construction projects,including how schedule compression can lead to quality risks,and how quality control may cause delays.It analyzes the interna...This paper explains the goal conflict between schedule and quality in construction projects,including how schedule compression can lead to quality risks,and how quality control may cause delays.It analyzes the internal logic of collaborative management and influencing factors such as construction plans.The paper also introduces collaborative management methods,such as establishing a responsibility traceability system based on Work Breakdown Structure(WBS),and emphasizes the role of intelligent construction technologies and their future development directions.展开更多
To design the optimum acceleration control schedule for the Adaptive Cycle Engine(ACE)in the full flight envelope,this paper establishes a direct simulation model of the ACE transient state.In this model,geometric par...To design the optimum acceleration control schedule for the Adaptive Cycle Engine(ACE)in the full flight envelope,this paper establishes a direct simulation model of the ACE transient state.In this model,geometric parameters are used to replace the component state parameters.The corresponding relationship between geometric parameters and component state parameters is determined by sensitivity analysis.The geometric variables are controlled when the geometric adjustment speed exceeds the limit,and at the same time the corresponding component state parameters are iterated.The gradient optimization algorism is used to optimize the ground acceleration process of ACE,and the control schedule in terms of operating point of compression components and corrected acceleration rate is used as the full-envelope acceleration control schedule based on the similarity principle.The acceleration control schedules of the triple-bypass mode and the double-bypass mode are designed in this paper.The acceleration processes under various flight conditions are simulated using the acceleration control schedules.Compared with the acceleration process with the linear geometric adjustment schedule,the acceleration performance of ACE is improved by the acceleration control schedule,with the impulse of the acceleration process of the triple-bypass mode being increased by 8.7%-12.3% and the impulse of the double-bypass mode acceleration process being increased by 11.8%-14.1%.展开更多
California is one of the major alfalfa (Medicago sativa L) forage-producing states in the U.S, but its production area has decreased significantly in the last couple of decades. Selection of cultivars with high yield ...California is one of the major alfalfa (Medicago sativa L) forage-producing states in the U.S, but its production area has decreased significantly in the last couple of decades. Selection of cultivars with high yield and nutritive value under late-cutting schedule strategy may help identify cultivars that growers can use to maximize yield while maintaining area for sustainable alfalfa production, but there is little information on this strategy. A field study was conducted to determine cumulative dry matter (DM) and nutritive values of 20 semi- and non-fall dormant (FD) ratings (FD 7 and FD 8 - 10, respectively) cultivars under 35-day cut in California’s Central Valley in 2020-2022. Seasonal cumulative DM yields ranged from 6.8 in 2020 to 37.0 Mg·ha−1 in 2021. Four FD 8 - 9 cultivars were the highest yielding with 3-yrs avg. DM greater than the lowest yielding lines by 46%. FD 7 cultivar “715RR” produced the highest crude protein (CP: 240 g·Kg−1) while FD 8 cultivar “HVX840RR” resulted in the highest neutral detergent fiber digestibility (NDFD: 484 g·Kg−1, 7% greater than the top yielding cultivars) but with DM yield intermediate. Yields and NDFD correlated positively but weakly indicating some semi- and non-FD cultivars performing similarly. These results suggest that selecting high yielding cultivars under 35-day cutting schedule strategy can be used as a tool to help growers to maximize yield while achieving good quality forages for sustainable alfalfa production in California’s Central Valley.展开更多
Cloud computing provides a diverse and adaptable resource pool over the internet,allowing users to tap into various resources as needed.It has been seen as a robust solution to relevant challenges.A significant delay ...Cloud computing provides a diverse and adaptable resource pool over the internet,allowing users to tap into various resources as needed.It has been seen as a robust solution to relevant challenges.A significant delay can hamper the performance of IoT-enabled cloud platforms.However,efficient task scheduling can lower the cloud infrastructure’s energy consumption,thus maximizing the service provider’s revenue by decreasing user job processing times.The proposed Modified Chimp-Whale Optimization Algorithm called Modified Chimp-Whale Optimization Algorithm(MCWOA),combines elements of the Chimp Optimization Algorithm(COA)and the Whale Optimization Algorithm(WOA).To enhance MCWOA’s identification precision,the Sobol sequence is used in the population initialization phase,ensuring an even distribution of the population across the solution space.Moreover,the traditional MCWOA’s local search capabilities are augmented by incorporating the whale optimization algorithm’s bubble-net hunting and random search mechanisms into MCWOA’s position-updating process.This study demonstrates the effectiveness of the proposed approach using a two-story rigid frame and a simply supported beam model.Simulated outcomes reveal that the new method outperforms the original MCWOA,especially in multi-damage detection scenarios.MCWOA excels in avoiding false positives and enhancing computational speed,making it an optimal choice for structural damage detection.The efficiency of the proposed MCWOA is assessed against metrics such as energy usage,computational expense,task duration,and delay.The simulated data indicates that the new MCWOA outpaces other methods across all metrics.The study also references the Whale Optimization Algorithm(WOA),Chimp Algorithm(CA),Ant Lion Optimizer(ALO),Genetic Algorithm(GA)and Grey Wolf Optimizer(GWO).展开更多
The evolutionary strategy with a dynamic weighting schedule is proposed to find all the compromised solutions of the multi-objective integrated structure and control optimization problem, where the optimal system perf...The evolutionary strategy with a dynamic weighting schedule is proposed to find all the compromised solutions of the multi-objective integrated structure and control optimization problem, where the optimal system performance and control cost are defined by H2 or H∞ norms. During this optimization process, the weights are varying with the increasing generation instead of fixed values. The proposed strategy together with the linear matrix inequality （LMI） or the Riccati controller design method can find a series of uniformly distributed nondominated solutions in a single run. Therefore, this method can greatly reduce the computation intensity of the integrated optimization problem compared with the weight-based single objective genetic algorithm. Active automotive suspension is adopted as an example to illustrate the effectiveness of the proposed method.展开更多
Lean construction has been newly applied to construction industry. The best performance of a project can be achieved through the precise definition of construction product, rational work break structure, lean supply c...Lean construction has been newly applied to construction industry. The best performance of a project can be achieved through the precise definition of construction product, rational work break structure, lean supply chain, decrease of resources waste, objective control and so forth. Referring to the characteristics of schedule planning of construction projects and lean construction philosophy, we proposed optimizing methodology of real-time and dynamic schedule of construction projects based on lean construction. The basis of the methodology is process reorganization and lean supply in construction enterprises. The traditional estimating method of the activity duration is fuzzy and random;however, a newly proposed lean forecasting method employs multi-components linear-regression, back-propagation artificial neural networks and learning curve. Taking account of the limited resources and the fixed duration of a project, the optimizing method of the real-time and dynamic schedule adopts the concept of resource driving. To optimize the schedule of a construction project timely and effectively, an intellectualized schedule management system was developed. It can work out the initial schedule, optimize the real-time and dynamic schedule, and display the schedule with the Gant Chart, the net-work graph and the space-time line chart. A case study was also presented to explain the proposed method.展开更多
By thorough research on the prominent periodic and aperiodic scheduling algorithms,anon-line hard real-time scheduler is presented,which is applicable to the scheduling of packets over a link.This scheduler,based on b...By thorough research on the prominent periodic and aperiodic scheduling algorithms,anon-line hard real-time scheduler is presented,which is applicable to the scheduling of packets over a link.This scheduler,based on both Rate Monotonic,pinwheel scheduling algorithm Sr and Polling Serverscheduling algorithms,can rapidly judge the schedulability and then automatically generate a bus tablefor the scheduling algorithm to schedule the packets as the periodic packets.The implementation of thescheduler is simple and easy to use,and it is effective for the utilization of bus link.The orderly executionof the bus table can not only guarantee the performance of the hard real time but also avoid the blockageand interruption of the message transmission.So the scheduler perfectly meets the demand of hard real-time communication system on the field bus domain.展开更多
To improve ground vehicle efficiency, shift schedule energy saving was proposed for the ground vehicle automatic transmission by studying the function of the torque converter and transmission in the vehicular drivetra...To improve ground vehicle efficiency, shift schedule energy saving was proposed for the ground vehicle automatic transmission by studying the function of the torque converter and transmission in the vehicular drivetrain. The shift schedule can keep the torque converter working in the high efficiency range under all the working conditions except in the low efficiency range on the left when the transmission worked at the lowest shift, and in the low efficiency range on the right when the transmission worked at the highest shift. The shift quality key factors were analysed. The automatic trans-mission's bench-test adopting this shift schedule was made on the automatic transmission's test-bed. The experimental results showed that the shift schedule was correct and that the shift quality was controllable.展开更多
Studies show that different geometries of a Variable Cycle Engine(VCE)can be adjusted during the transient stage of the engine operation to improve the engine performance.However,this improvement increases the complex...Studies show that different geometries of a Variable Cycle Engine(VCE)can be adjusted during the transient stage of the engine operation to improve the engine performance.However,this improvement increases the complexity of the acceleration and deceleration control schedule.In order to resolve this problem,the Transient-state Reverse Method(TRM)is established in the present study based on the Steady-state Reverse Method(SRM)and the Virtual Power Extraction Method(VPEM).The state factors in the component-based engine performance models are replaced by variable geometry parameters to establish the TRM for a double bypass VCE.Obtained results are compared with the conventional component-based model from different aspects,including the accuracy and the convergence rate.The TRM is then employed to optimize the control schedule of a VCE.Obtained results show that the accuracy and the convergence rate of the proposed method are consistent with that of the conventional model.On the other hand,it is found that the new-model-optimized control schedules reduce the acceleration and deceleration time by 45%and 54%,respectively.Meanwhile,the surge margin of compressors,fuel–air ratio and the turbine inlet temperature maintained are within the acceptable criteria.It is concluded that the proposed TRM is a powerful method to design the acceleration and deceleration control schedule of the VCE.展开更多
A genetic algorithm-based optimization was used for 1 370 mm tandem cold rolling schedule,in which the press rates were coded and operated.The superiority individual is reserved in every generation.Analysis and compar...A genetic algorithm-based optimization was used for 1 370 mm tandem cold rolling schedule,in which the press rates were coded and operated.The superiority individual is reserved in every generation.Analysis and comparison of optimized schedule with the existing schedule were offered.It is seen that the performance of the optimal rolling schedule is satisfactory and promising.展开更多
AIM: To establish the safety and efficacy of an indigenously developed r-hepatitis B vaccine using an accelerated schedule and to highlight the social awareness and commitment in preventing the spreading of hepatitis ...AIM: To establish the safety and efficacy of an indigenously developed r-hepatitis B vaccine using an accelerated schedule and to highlight the social awareness and commitment in preventing the spreading of hepatitis B virus infection. METHODS: The study was a multicentric, double blind, randomized (3:1) study using three doses of vaccine immunization schedule (20μg for those above 10 years old and 10 μg for those below 10 years old) on d 0, 30 and 60. One hundred and sixty-six subjects were enrolled (87 males and 76 females aged 5-35 years). The main outcome measure was assessment of immunogenicity and safety. RESULTS: A 100% seroconversion response was observed on the 30th d after the 1st injection in both the experimental groups. The sero-protection data reported a 41.2-65.6% response on the 30th d after the 1st injection and reached 100% on the 60th d. Descriptive statistical analysis showed a geometric mean titer value of 13.77 mIU/mL in the test (BEVAC) group and 10.95 mlU/mL in the commercial control (ENGERIX-B) group on the 30th d after the 1st injection. The response on the 60th d showed a geometric mean titre value (GMT) of 519.84 mlU/mL in the BEVAC group and 475.46 mlU/mL in the ENGERIX-B group. On the 90th d, the antibody titer response was observed to be 2627.58 mlU/mL in the BEVAC group and 2272.72 mlU/mL in the ENGERIX-B group. Two subjects in each group experienced pains at injection site after the first vaccination. A total of six subjects in both groups experienced a solicited adverse reaction, which included pains, swelling and redness at the injection site, three subjects in the group-B had a pain at the injection site after the third dose. No other serious adverse events occurred and no dose-related local or general symptoms were observed during the study. CONCLUSION: The vaccine is safe, efficacious and immunogenic in comparison with the well documented ENGERIX-B.展开更多
开发Java Web项目中发现服务之间的调用存在超时情况,由于涉及的处理逻辑全部是异步,引入定时重试的机制,重试工具选择了JDK自带的Scheduled Thread Pool Executor。当A服务依赖B服务,B服务由于在业务高峰期处理能力降低,导致大量A服务...开发Java Web项目中发现服务之间的调用存在超时情况,由于涉及的处理逻辑全部是异步,引入定时重试的机制,重试工具选择了JDK自带的Scheduled Thread Pool Executor。当A服务依赖B服务,B服务由于在业务高峰期处理能力降低,导致大量A服务过来的请求超时,A加入了超时重试机制,间隔时间根据重试次数的多少来决定,次数越多,两次重试之间间隔的时间越多,此时的业务高峰也会给A带来大量请求,大量的超时会导致重试队列迅速堆积,直到内存溢出。该文从线程池工作机制、Scheduled Thread Pool Executor实例的创建,获取重试任务的过程以及提交任务的过程角度分析,并通过源代码的剖析和测试工具My Eclipse进行演示测试内存泄露的情况,得出避免内存泄露的解决方案。展开更多
Servicing is applied periodically in practice with the aim of restoring the system state and prolonging the lifetime. It is generally seen as an imperfect maintenance action which has a chief influence on the maintena...Servicing is applied periodically in practice with the aim of restoring the system state and prolonging the lifetime. It is generally seen as an imperfect maintenance action which has a chief influence on the maintenance strategy. In order to model the maintenance effect of servicing, this study analyzes the deterioration characteristics of system under scheduled servicing. And then the deterioration model is established from the failure mechanism by compound Poisson process. On the basis of the system damage value and failure mechanism, the failure rate refresh factor is proposed to describe the maintenance effect of servicing. A maintenance strategy is developed which combines the benefits of scheduled servicing and preventive maintenance. Then the optimization model is given to determine the optimal servicing period and preventive maintenance time, with an objective to minimize the system expected life-cycle cost per unit time and a constraint on system survival probability for the duration of mission time. Subject to mission time, it can control the ability of accomplishing the mission at any time so as to ensure the high dependability. An example of water pump rotor relating to scheduled servicing is introduced to illustrate the failure rate refresh factor and the proposed maintenance strategy. Compared with traditional methods, the numerical results show that the failure rate refresh factor can describe the maintenance effect of servicing more intuitively and objectively. It also demonstrates that this maintenance strategy can prolong the lifetime, reduce the total lifetime maintenance cost and guarantee the dependability of system.展开更多
The alternative working modes and flexible working states are the outstanding features of an adaptive cycle engine, with a proper control schedule design being the only way to exploit the performance of such an engine...The alternative working modes and flexible working states are the outstanding features of an adaptive cycle engine, with a proper control schedule design being the only way to exploit the performance of such an engine. However, unreasonable design in the control schedule causes not only performance deterioration but also serious aerodynamic stability problems. Thus, in this work,a hybrid optimization method that automatically chooses the working modes and identifies the optimal and smooth control schedules is proposed, by combining the differential evolution algorithm and the Latin hypercube sampling method. The control schedule architecture does not only optimize the engine steady-state performance under different working modes but also solves the control-schedule discontinuity problem, especially during mode transition. The optimal control schedules are continuous and almost monotonic, and hence are strongly suitable for a control system, and are designed for two different working conditions, i.e., supersonic and subsonic throttling,which proves that the proposed hybrid method applies to various working conditions. The evaluation demonstrates that the proposed control method optimizes the engine performance, the surge margin of the compression components, and the range of the thrust during throttling.展开更多
Considering the multivariable, strong-coupled, and nonlinear features of tandem cold rolling mill, a mathematical model of multi-objective optimization was built to facilitate the design of new systems aiming at equat...Considering the multivariable, strong-coupled, and nonlinear features of tandem cold rolling mill, a mathematical model of multi-objective optimization was built to facilitate the design of new systems aiming at equating the relative load, preventing slip, and obtaining best shape. BP （back propagation） neural network based on Levenberg- Marquardt algorithm was used for predicting the rolling force. The multi-objective fuzzy theory and method were introduced during the optimization. With an example of 1 370 mm tandem cold rolling mill, the rolling schedule of the common rolling, the single-objective optimization design, and the multi-objective fuzzy optimization design were compared with each other. The results generated from the case study showed that the proposed approach could significantly decreased the values of three objective functions simultaneously and the performance of the optimal rolling schedule was satisfactory and promising. Moreover, the capability and usefulness of fuzzy application in tandem cold rolling schedule were clearly demonstrated.展开更多
Rolling schedule not only determines the rolling process to be going smoothly, but also affects the shape accuracy and structure properties of finished strip. In order to gain good strip crown and flatness, the calcul...Rolling schedule not only determines the rolling process to be going smoothly, but also affects the shape accuracy and structure properties of finished strip. In order to gain good strip crown and flatness, the calculation formulas of the most suitable rolling force and bending force are deduced. By taking relatively equal load of rolling power and good shape as objective functions, the optimization mathematical models of finish rolling schedule are established. By contrast, the rolling schedules after optimization can improve the rolling mill working status and ensure the strip crown and flatness to be good. At the same time, the setting value of bending force is improved and this leaves more space for on-line shape control.展开更多
基金supported by the Basic Research on Dynamic Real-time Modeling and Onboard Adaptive Modeling of Aero Engine,China(No.QZPY202308)。
文摘Variable Cycle Engine(VCE)serves as the core system in achieving future advanced fighters with cross-generational performance and mission versatility.However,the resultant complex configuration and strong coupling of control parameters present significant challenges in designing acceleration and deceleration control schedules.To thoroughly explore the performance potential of engine,a global integration design method for acceleration and deceleration control schedule based on inner and outer loop optimization is proposed.The outer loop optimization module employs Integrated Surrogate-Assisted Co-Differential Evolutionary(ISACDE)algorithm to optimize the variable geometry adjustment laws based on B-spline curve,and the inner loop optimization module adopts the fixed-state method to design the open-loop fuel–air ratio control schedules,which are aimed at minimizing the acceleration and deceleration time under multiple constraints.Simulation results demonstrate that the proposed global integration design method not only furthest shortens the acceleration and deceleration time,but also effectively safeguards the engine from overlimit.
文摘This paper explains the goal conflict between schedule and quality in construction projects,including how schedule compression can lead to quality risks,and how quality control may cause delays.It analyzes the internal logic of collaborative management and influencing factors such as construction plans.The paper also introduces collaborative management methods,such as establishing a responsibility traceability system based on Work Breakdown Structure(WBS),and emphasizes the role of intelligent construction technologies and their future development directions.
基金co-supported by the National Science and Technology Major Project,China(No.J2019-I-0015-0014)the National Natural Science Foundation of China(No.52372397).
文摘To design the optimum acceleration control schedule for the Adaptive Cycle Engine(ACE)in the full flight envelope,this paper establishes a direct simulation model of the ACE transient state.In this model,geometric parameters are used to replace the component state parameters.The corresponding relationship between geometric parameters and component state parameters is determined by sensitivity analysis.The geometric variables are controlled when the geometric adjustment speed exceeds the limit,and at the same time the corresponding component state parameters are iterated.The gradient optimization algorism is used to optimize the ground acceleration process of ACE,and the control schedule in terms of operating point of compression components and corrected acceleration rate is used as the full-envelope acceleration control schedule based on the similarity principle.The acceleration control schedules of the triple-bypass mode and the double-bypass mode are designed in this paper.The acceleration processes under various flight conditions are simulated using the acceleration control schedules.Compared with the acceleration process with the linear geometric adjustment schedule,the acceleration performance of ACE is improved by the acceleration control schedule,with the impulse of the acceleration process of the triple-bypass mode being increased by 8.7%-12.3% and the impulse of the double-bypass mode acceleration process being increased by 11.8%-14.1%.
文摘California is one of the major alfalfa (Medicago sativa L) forage-producing states in the U.S, but its production area has decreased significantly in the last couple of decades. Selection of cultivars with high yield and nutritive value under late-cutting schedule strategy may help identify cultivars that growers can use to maximize yield while maintaining area for sustainable alfalfa production, but there is little information on this strategy. A field study was conducted to determine cumulative dry matter (DM) and nutritive values of 20 semi- and non-fall dormant (FD) ratings (FD 7 and FD 8 - 10, respectively) cultivars under 35-day cut in California’s Central Valley in 2020-2022. Seasonal cumulative DM yields ranged from 6.8 in 2020 to 37.0 Mg·ha−1 in 2021. Four FD 8 - 9 cultivars were the highest yielding with 3-yrs avg. DM greater than the lowest yielding lines by 46%. FD 7 cultivar “715RR” produced the highest crude protein (CP: 240 g·Kg−1) while FD 8 cultivar “HVX840RR” resulted in the highest neutral detergent fiber digestibility (NDFD: 484 g·Kg−1, 7% greater than the top yielding cultivars) but with DM yield intermediate. Yields and NDFD correlated positively but weakly indicating some semi- and non-FD cultivars performing similarly. These results suggest that selecting high yielding cultivars under 35-day cutting schedule strategy can be used as a tool to help growers to maximize yield while achieving good quality forages for sustainable alfalfa production in California’s Central Valley.
文摘Cloud computing provides a diverse and adaptable resource pool over the internet,allowing users to tap into various resources as needed.It has been seen as a robust solution to relevant challenges.A significant delay can hamper the performance of IoT-enabled cloud platforms.However,efficient task scheduling can lower the cloud infrastructure’s energy consumption,thus maximizing the service provider’s revenue by decreasing user job processing times.The proposed Modified Chimp-Whale Optimization Algorithm called Modified Chimp-Whale Optimization Algorithm(MCWOA),combines elements of the Chimp Optimization Algorithm(COA)and the Whale Optimization Algorithm(WOA).To enhance MCWOA’s identification precision,the Sobol sequence is used in the population initialization phase,ensuring an even distribution of the population across the solution space.Moreover,the traditional MCWOA’s local search capabilities are augmented by incorporating the whale optimization algorithm’s bubble-net hunting and random search mechanisms into MCWOA’s position-updating process.This study demonstrates the effectiveness of the proposed approach using a two-story rigid frame and a simply supported beam model.Simulated outcomes reveal that the new method outperforms the original MCWOA,especially in multi-damage detection scenarios.MCWOA excels in avoiding false positives and enhancing computational speed,making it an optimal choice for structural damage detection.The efficiency of the proposed MCWOA is assessed against metrics such as energy usage,computational expense,task duration,and delay.The simulated data indicates that the new MCWOA outpaces other methods across all metrics.The study also references the Whale Optimization Algorithm(WOA),Chimp Algorithm(CA),Ant Lion Optimizer(ALO),Genetic Algorithm(GA)and Grey Wolf Optimizer(GWO).
文摘The evolutionary strategy with a dynamic weighting schedule is proposed to find all the compromised solutions of the multi-objective integrated structure and control optimization problem, where the optimal system performance and control cost are defined by H2 or H∞ norms. During this optimization process, the weights are varying with the increasing generation instead of fixed values. The proposed strategy together with the linear matrix inequality （LMI） or the Riccati controller design method can find a series of uniformly distributed nondominated solutions in a single run. Therefore, this method can greatly reduce the computation intensity of the integrated optimization problem compared with the weight-based single objective genetic algorithm. Active automotive suspension is adopted as an example to illustrate the effectiveness of the proposed method.
文摘Lean construction has been newly applied to construction industry. The best performance of a project can be achieved through the precise definition of construction product, rational work break structure, lean supply chain, decrease of resources waste, objective control and so forth. Referring to the characteristics of schedule planning of construction projects and lean construction philosophy, we proposed optimizing methodology of real-time and dynamic schedule of construction projects based on lean construction. The basis of the methodology is process reorganization and lean supply in construction enterprises. The traditional estimating method of the activity duration is fuzzy and random;however, a newly proposed lean forecasting method employs multi-components linear-regression, back-propagation artificial neural networks and learning curve. Taking account of the limited resources and the fixed duration of a project, the optimizing method of the real-time and dynamic schedule adopts the concept of resource driving. To optimize the schedule of a construction project timely and effectively, an intellectualized schedule management system was developed. It can work out the initial schedule, optimize the real-time and dynamic schedule, and display the schedule with the Gant Chart, the net-work graph and the space-time line chart. A case study was also presented to explain the proposed method.
基金Supported by the Emphases Science and Technology Project Foundation of Sichuan Province(NO.02GG006-037)
文摘By thorough research on the prominent periodic and aperiodic scheduling algorithms,anon-line hard real-time scheduler is presented,which is applicable to the scheduling of packets over a link.This scheduler,based on both Rate Monotonic,pinwheel scheduling algorithm Sr and Polling Serverscheduling algorithms,can rapidly judge the schedulability and then automatically generate a bus tablefor the scheduling algorithm to schedule the packets as the periodic packets.The implementation of thescheduler is simple and easy to use,and it is effective for the utilization of bus link.The orderly executionof the bus table can not only guarantee the performance of the hard real time but also avoid the blockageand interruption of the message transmission.So the scheduler perfectly meets the demand of hard real-time communication system on the field bus domain.
文摘To improve ground vehicle efficiency, shift schedule energy saving was proposed for the ground vehicle automatic transmission by studying the function of the torque converter and transmission in the vehicular drivetrain. The shift schedule can keep the torque converter working in the high efficiency range under all the working conditions except in the low efficiency range on the left when the transmission worked at the lowest shift, and in the low efficiency range on the right when the transmission worked at the highest shift. The shift quality key factors were analysed. The automatic trans-mission's bench-test adopting this shift schedule was made on the automatic transmission's test-bed. The experimental results showed that the shift schedule was correct and that the shift quality was controllable.
基金supported by the Aviation Power Foundation of China(6141B09050382)。
文摘Studies show that different geometries of a Variable Cycle Engine(VCE)can be adjusted during the transient stage of the engine operation to improve the engine performance.However,this improvement increases the complexity of the acceleration and deceleration control schedule.In order to resolve this problem,the Transient-state Reverse Method(TRM)is established in the present study based on the Steady-state Reverse Method(SRM)and the Virtual Power Extraction Method(VPEM).The state factors in the component-based engine performance models are replaced by variable geometry parameters to establish the TRM for a double bypass VCE.Obtained results are compared with the conventional component-based model from different aspects,including the accuracy and the convergence rate.The TRM is then employed to optimize the control schedule of a VCE.Obtained results show that the accuracy and the convergence rate of the proposed method are consistent with that of the conventional model.On the other hand,it is found that the new-model-optimized control schedules reduce the acceleration and deceleration time by 45%and 54%,respectively.Meanwhile,the surge margin of compressors,fuel–air ratio and the turbine inlet temperature maintained are within the acceptable criteria.It is concluded that the proposed TRM is a powerful method to design the acceleration and deceleration control schedule of the VCE.
文摘A genetic algorithm-based optimization was used for 1 370 mm tandem cold rolling schedule,in which the press rates were coded and operated.The superiority individual is reserved in every generation.Analysis and comparison of optimized schedule with the existing schedule were offered.It is seen that the performance of the optimal rolling schedule is satisfactory and promising.
基金Supported by the Biological E Limited, Hyderabad, India
文摘AIM: To establish the safety and efficacy of an indigenously developed r-hepatitis B vaccine using an accelerated schedule and to highlight the social awareness and commitment in preventing the spreading of hepatitis B virus infection. METHODS: The study was a multicentric, double blind, randomized (3:1) study using three doses of vaccine immunization schedule (20μg for those above 10 years old and 10 μg for those below 10 years old) on d 0, 30 and 60. One hundred and sixty-six subjects were enrolled (87 males and 76 females aged 5-35 years). The main outcome measure was assessment of immunogenicity and safety. RESULTS: A 100% seroconversion response was observed on the 30th d after the 1st injection in both the experimental groups. The sero-protection data reported a 41.2-65.6% response on the 30th d after the 1st injection and reached 100% on the 60th d. Descriptive statistical analysis showed a geometric mean titer value of 13.77 mIU/mL in the test (BEVAC) group and 10.95 mlU/mL in the commercial control (ENGERIX-B) group on the 30th d after the 1st injection. The response on the 60th d showed a geometric mean titre value (GMT) of 519.84 mlU/mL in the BEVAC group and 475.46 mlU/mL in the ENGERIX-B group. On the 90th d, the antibody titer response was observed to be 2627.58 mlU/mL in the BEVAC group and 2272.72 mlU/mL in the ENGERIX-B group. Two subjects in each group experienced pains at injection site after the first vaccination. A total of six subjects in both groups experienced a solicited adverse reaction, which included pains, swelling and redness at the injection site, three subjects in the group-B had a pain at the injection site after the third dose. No other serious adverse events occurred and no dose-related local or general symptoms were observed during the study. CONCLUSION: The vaccine is safe, efficacious and immunogenic in comparison with the well documented ENGERIX-B.
文摘开发Java Web项目中发现服务之间的调用存在超时情况,由于涉及的处理逻辑全部是异步,引入定时重试的机制,重试工具选择了JDK自带的Scheduled Thread Pool Executor。当A服务依赖B服务,B服务由于在业务高峰期处理能力降低,导致大量A服务过来的请求超时,A加入了超时重试机制,间隔时间根据重试次数的多少来决定,次数越多,两次重试之间间隔的时间越多,此时的业务高峰也会给A带来大量请求,大量的超时会导致重试队列迅速堆积,直到内存溢出。该文从线程池工作机制、Scheduled Thread Pool Executor实例的创建,获取重试任务的过程以及提交任务的过程角度分析,并通过源代码的剖析和测试工具My Eclipse进行演示测试内存泄露的情况,得出避免内存泄露的解决方案。
基金supported by the National Defence Preresearch Foundation of China(Nos.51327020105,51304010206)
文摘Servicing is applied periodically in practice with the aim of restoring the system state and prolonging the lifetime. It is generally seen as an imperfect maintenance action which has a chief influence on the maintenance strategy. In order to model the maintenance effect of servicing, this study analyzes the deterioration characteristics of system under scheduled servicing. And then the deterioration model is established from the failure mechanism by compound Poisson process. On the basis of the system damage value and failure mechanism, the failure rate refresh factor is proposed to describe the maintenance effect of servicing. A maintenance strategy is developed which combines the benefits of scheduled servicing and preventive maintenance. Then the optimization model is given to determine the optimal servicing period and preventive maintenance time, with an objective to minimize the system expected life-cycle cost per unit time and a constraint on system survival probability for the duration of mission time. Subject to mission time, it can control the ability of accomplishing the mission at any time so as to ensure the high dependability. An example of water pump rotor relating to scheduled servicing is introduced to illustrate the failure rate refresh factor and the proposed maintenance strategy. Compared with traditional methods, the numerical results show that the failure rate refresh factor can describe the maintenance effect of servicing more intuitively and objectively. It also demonstrates that this maintenance strategy can prolong the lifetime, reduce the total lifetime maintenance cost and guarantee the dependability of system.
基金funded by National Nature Science Foundation of China(Nos.51776010 and 91860205)supported by the Academic Excellence Foundation of BUAA for PhD Students,China。
文摘The alternative working modes and flexible working states are the outstanding features of an adaptive cycle engine, with a proper control schedule design being the only way to exploit the performance of such an engine. However, unreasonable design in the control schedule causes not only performance deterioration but also serious aerodynamic stability problems. Thus, in this work,a hybrid optimization method that automatically chooses the working modes and identifies the optimal and smooth control schedules is proposed, by combining the differential evolution algorithm and the Latin hypercube sampling method. The control schedule architecture does not only optimize the engine steady-state performance under different working modes but also solves the control-schedule discontinuity problem, especially during mode transition. The optimal control schedules are continuous and almost monotonic, and hence are strongly suitable for a control system, and are designed for two different working conditions, i.e., supersonic and subsonic throttling,which proves that the proposed hybrid method applies to various working conditions. The evaluation demonstrates that the proposed control method optimizes the engine performance, the surge margin of the compression components, and the range of the thrust during throttling.
基金Item Sponsored by National Key Technology Research and Development Programin 11th Five-Year Plan of China(2007BAF02B12)
文摘Considering the multivariable, strong-coupled, and nonlinear features of tandem cold rolling mill, a mathematical model of multi-objective optimization was built to facilitate the design of new systems aiming at equating the relative load, preventing slip, and obtaining best shape. BP （back propagation） neural network based on Levenberg- Marquardt algorithm was used for predicting the rolling force. The multi-objective fuzzy theory and method were introduced during the optimization. With an example of 1 370 mm tandem cold rolling mill, the rolling schedule of the common rolling, the single-objective optimization design, and the multi-objective fuzzy optimization design were compared with each other. The results generated from the case study showed that the proposed approach could significantly decreased the values of three objective functions simultaneously and the performance of the optimal rolling schedule was satisfactory and promising. Moreover, the capability and usefulness of fuzzy application in tandem cold rolling schedule were clearly demonstrated.
基金Item Sponsored by National Natural Science Foundation of China(51075353)Hebei Natural Science Foundation of China(E2010001208)
文摘Rolling schedule not only determines the rolling process to be going smoothly, but also affects the shape accuracy and structure properties of finished strip. In order to gain good strip crown and flatness, the calculation formulas of the most suitable rolling force and bending force are deduced. By taking relatively equal load of rolling power and good shape as objective functions, the optimization mathematical models of finish rolling schedule are established. By contrast, the rolling schedules after optimization can improve the rolling mill working status and ensure the strip crown and flatness to be good. At the same time, the setting value of bending force is improved and this leaves more space for on-line shape control.
