Gust response alleviation is very important for helicopters which have strong coupling and vibration. Gust disturbance not only influences the ride quality and the precision of the weapon delivery, but also affects to...Gust response alleviation is very important for helicopters which have strong coupling and vibration. Gust disturbance not only influences the ride quality and the precision of the weapon delivery, but also affects to the structural fatigue load and the strength. The method of an optimal control law to suppress the gust disturbance for helicopters is presented. The optimization requires the minimization of the vertical overload at the pilot′s seat, the attitude variation and the control energy consumption under the gust disturbance. Based on the original control system, the new system can be easily realized by adding a vertical speed feedback passage. In order to develop the real-time operational flight control system, the optimized control law is written in C language. The hybrid simulations prove that the performance of gust response alleviation and the efficiency of digitalization are satisfactory.展开更多
An intelligent response surface methodology (IRSM) was proposed to achieve the most competitive metal forming products, in which artificial intelligence technologies are introduced into the optimization process. It is...An intelligent response surface methodology (IRSM) was proposed to achieve the most competitive metal forming products, in which artificial intelligence technologies are introduced into the optimization process. It is used as simple and inexpensive replacement for computationally expensive simulation model. In IRSM, the optimal design space can be reduced greatly without any prior information about function distribution. Also, by identifying the approximation error region, new design points can be supplemented correspondingly to improve the response surface model effectively. The procedure is iterated until the accuracy reaches the desired threshold value. Thus, the global optimization can be performed based on this substitute model. Finally, we present an optimization design example about roll forming of a "U" channel product.展开更多
Based on frequency response and convex optimization,a novel optimal control system was developed for chemical processes.The feedforward control is designed to improve the tracking performance of closed loop chemical s...Based on frequency response and convex optimization,a novel optimal control system was developed for chemical processes.The feedforward control is designed to improve the tracking performance of closed loop chemical systems.The parametric model is not required because the system directly utilizes the frequency response of the loop transfer function,which can be measured accurately.In particular,the extremal values of magnitude and phase can be solved according to constrained quadratic programming optimizer and convex optimization.Simulation examples show the effectiveness of the method.The design method is simple and easily adopted in chemical industry.展开更多
This paper proposes a novel iterative algorithm for optimal design of non-frequency-selective Finite Impulse Response(FIR) digital filters based on the windowing method.Different from the traditional optimization conc...This paper proposes a novel iterative algorithm for optimal design of non-frequency-selective Finite Impulse Response(FIR) digital filters based on the windowing method.Different from the traditional optimization concept of adjusting the window or the filter order in the windowing design of an FIR digital filter,the key idea of the algorithm is minimizing the approximation error by succes-sively modifying the design result through an iterative procedure under the condition of a fixed window length.In the iterative procedure,the known deviation of the designed frequency response in each iteration from the ideal frequency response is used as a reference for the next iteration.Because the approximation error can be specified variably,the algorithm is applicable for the design of FIR digital filters with different technical requirements in the frequency domain.A design example is employed to illustrate the efficiency of the algorithm.展开更多
Most of modern tall buildings using lighter construction materials with high strength and less stiffness are more flexible, which occurs excessive wind-induced vibration, resulting in occupant discomfort and structura...Most of modern tall buildings using lighter construction materials with high strength and less stiffness are more flexible, which occurs excessive wind-induced vibration, resulting in occupant discomfort and structural unsafety. It is necessary to predict wind-induced vibration response and find out a method to mitigate such an excessive wind-induced vibration at the preliminary design stage. Recently, many studies have been conducted in using actuator control force based on the linear quadratic optimum control algorithm. It was accepted as a common knowledge that the performance of passive tuned mass damper(TMD) could increase by incorporating a feedback active control force in the design of TMD, which is called active tuned mass damper(ATMD). However, the fact that ATMD is superior to TMD to reduce wind-induced vibration of a tall building is still a question. The effectiveness of TMD for mitigating the along-wind vibration of a tall building was investigated. Optimum parameters of tuning frequency and damping ratio for TMD under a random load which has a white noise spectra were used. Fluctuating along-wind load acting on a tall building treated as a stationary Gaussian random process was simulated numerically using the along-wind load spectra. And using this simulated along-wind load, along-wind responses of a tall building with and without TMD were calculated and the effectiveness of TMD in mitigating the along-wind response of a tall building was found out.展开更多
This study was conducted to investigate the effects of cellulase dosage, enzymolysis time, pH and enzymolysis temperature on procyanidin extraction rate by single factor experiment, with tartary buckwheat shell as an ...This study was conducted to investigate the effects of cellulase dosage, enzymolysis time, pH and enzymolysis temperature on procyanidin extraction rate by single factor experiment, with tartary buckwheat shell as an experimental material.Main process parameters were optimized to obtain a regression model by response surface methodology. The results of variance analysis indicated that the regression model reflected the relationship between buckwheat shell procyanidin extraction rate with enzyme dosage, enzymolysis time, pH and enzymolysis temperature; and the optimal process parameters were enzyme dosage of 6.5 mg/g, enzymolysis time of 1.5 h, pH at 4.7 and enzymolysis temperature at 46 ℃. Three parallel experiments were conducted under these process parameters. In practice, the highest procyanidin extraction rate was 6.78 g/100 g. The relative error between the predicted value of regression model and the actual value was 1.3%. The regression equation fitted the real situation better.展开更多
A weakly coupled data assimilation system was established for a coupled physical–biological model for the northeastern South China Sea（NSCS）. The physical model used was the Regional Ocean Modeling System; the biol...A weakly coupled data assimilation system was established for a coupled physical–biological model for the northeastern South China Sea（NSCS）. The physical model used was the Regional Ocean Modeling System; the biological component was a seven-compartment nitrogen–phytoplankton–zooplankton–detritus ecosystem model; and the data assimilation method was Ensemble Optical Interpolation. To test the performance of the weakly coupled data assimilation system, two numerical experiments（i.e. control and assimilation runs） based on a process-oriented idealized case were conducted, and climatological SST was assimilated in the assimilation run. Only physical variables were adjusted in the weakly coupled data assimilation. The results showed that both the assimilated SST and other unassimilated physical variables had reasonable process responses. Due to the warmer SST observation, the water temperature（salinity） in the assimilation run increased（decreased） in coastal upwelling regions. Both the alongshore and bottom cross-shore currents were reduced, jointly demonstrating the weakening of the upwelling system. Meanwhile, ecosystem variables were also affected to some extent by the SST assimilation through the coupled model. For example, larger phytoplankton（chlorophyll） productivity was found in the upwelling region within the shallow layer due to the warmer waters in the assimilation run. Hence, the application of this data assimilation system could reasonably modify both physical and biological variables for the NSCS by SST assimilation.展开更多
Response surface methodology (RSM) is used to optimize the medium of Tetraselmis sp.-1 which is cell fused microalgae capable of growing under mixotrophic condition. Empirical models are developed to describe the rela...Response surface methodology (RSM) is used to optimize the medium of Tetraselmis sp.-1 which is cell fused microalgae capable of growing under mixotrophic condition. Empirical models are developed to describe the relationships between the operating variables (glucose, urea, sodium dehydrogenate phosphate, sodium chloride) and responses (cell density). Statistical analysis indicates that glucose and urea have significant effects on the microalgae cell density, but other two factors (sodium dehydrogenate phosphate, sodium chloride) have no obvious effect. The path of steepest ascent is used to approach the optimal region of medium composition. Optimal cell density (2.638 g dry weight/L) was reached when the operating conditions were glucose concentration (30.75 %), urea concentration (0.440 g/L), sodium dehydrogenate phosphate (15 mg/L) and sodium chloride (28 g/L).展开更多
This paper presents a prey-predator model considering the predator interacting with non-refuges prey by class of functional responses. Here we also consider harvesting for only non-refuges prey. We discuss the equilib...This paper presents a prey-predator model considering the predator interacting with non-refuges prey by class of functional responses. Here we also consider harvesting for only non-refuges prey. We discuss the equilibria of the model, and their stability for hiding prey either in constant form or proportional to the densities of prey population. We also investigate various possibilities of bionomic equilibrium and optimal harvesting policy. Finally we present numerical examples with pictorial presentation of the various effects of the prey predator system parameter.展开更多
文摘Gust response alleviation is very important for helicopters which have strong coupling and vibration. Gust disturbance not only influences the ride quality and the precision of the weapon delivery, but also affects to the structural fatigue load and the strength. The method of an optimal control law to suppress the gust disturbance for helicopters is presented. The optimization requires the minimization of the vertical overload at the pilot′s seat, the attitude variation and the control energy consumption under the gust disturbance. Based on the original control system, the new system can be easily realized by adding a vertical speed feedback passage. In order to develop the real-time operational flight control system, the optimized control law is written in C language. The hybrid simulations prove that the performance of gust response alleviation and the efficiency of digitalization are satisfactory.
文摘An intelligent response surface methodology (IRSM) was proposed to achieve the most competitive metal forming products, in which artificial intelligence technologies are introduced into the optimization process. It is used as simple and inexpensive replacement for computationally expensive simulation model. In IRSM, the optimal design space can be reduced greatly without any prior information about function distribution. Also, by identifying the approximation error region, new design points can be supplemented correspondingly to improve the response surface model effectively. The procedure is iterated until the accuracy reaches the desired threshold value. Thus, the global optimization can be performed based on this substitute model. Finally, we present an optimization design example about roll forming of a "U" channel product.
基金Supported by the National Natural Science Foundation of China（51205133） Natural Science Foundation of Shanghai（11ZR1409000） Ph.D.Programs Foundation of Ministry of Education of China（20110074120007）
文摘Based on frequency response and convex optimization,a novel optimal control system was developed for chemical processes.The feedforward control is designed to improve the tracking performance of closed loop chemical systems.The parametric model is not required because the system directly utilizes the frequency response of the loop transfer function,which can be measured accurately.In particular,the extremal values of magnitude and phase can be solved according to constrained quadratic programming optimizer and convex optimization.Simulation examples show the effectiveness of the method.The design method is simple and easily adopted in chemical industry.
基金the National Grand Fundamental Research 973 Program of China (No.2004CB318109)the National High-Technology Research and Development Plan of China (No.2006AA01Z452)
文摘This paper proposes a novel iterative algorithm for optimal design of non-frequency-selective Finite Impulse Response(FIR) digital filters based on the windowing method.Different from the traditional optimization concept of adjusting the window or the filter order in the windowing design of an FIR digital filter,the key idea of the algorithm is minimizing the approximation error by succes-sively modifying the design result through an iterative procedure under the condition of a fixed window length.In the iterative procedure,the known deviation of the designed frequency response in each iteration from the ideal frequency response is used as a reference for the next iteration.Because the approximation error can be specified variably,the algorithm is applicable for the design of FIR digital filters with different technical requirements in the frequency domain.A design example is employed to illustrate the efficiency of the algorithm.
基金Project(2011-0028567)supported by the National Research Foundation of Korea
文摘Most of modern tall buildings using lighter construction materials with high strength and less stiffness are more flexible, which occurs excessive wind-induced vibration, resulting in occupant discomfort and structural unsafety. It is necessary to predict wind-induced vibration response and find out a method to mitigate such an excessive wind-induced vibration at the preliminary design stage. Recently, many studies have been conducted in using actuator control force based on the linear quadratic optimum control algorithm. It was accepted as a common knowledge that the performance of passive tuned mass damper(TMD) could increase by incorporating a feedback active control force in the design of TMD, which is called active tuned mass damper(ATMD). However, the fact that ATMD is superior to TMD to reduce wind-induced vibration of a tall building is still a question. The effectiveness of TMD for mitigating the along-wind vibration of a tall building was investigated. Optimum parameters of tuning frequency and damping ratio for TMD under a random load which has a white noise spectra were used. Fluctuating along-wind load acting on a tall building treated as a stationary Gaussian random process was simulated numerically using the along-wind load spectra. And using this simulated along-wind load, along-wind responses of a tall building with and without TMD were calculated and the effectiveness of TMD in mitigating the along-wind response of a tall building was found out.
基金Supported by Shanxi Soft Science Research Program(2014041020-2)
文摘This study was conducted to investigate the effects of cellulase dosage, enzymolysis time, pH and enzymolysis temperature on procyanidin extraction rate by single factor experiment, with tartary buckwheat shell as an experimental material.Main process parameters were optimized to obtain a regression model by response surface methodology. The results of variance analysis indicated that the regression model reflected the relationship between buckwheat shell procyanidin extraction rate with enzyme dosage, enzymolysis time, pH and enzymolysis temperature; and the optimal process parameters were enzyme dosage of 6.5 mg/g, enzymolysis time of 1.5 h, pH at 4.7 and enzymolysis temperature at 46 ℃. Three parallel experiments were conducted under these process parameters. In practice, the highest procyanidin extraction rate was 6.78 g/100 g. The relative error between the predicted value of regression model and the actual value was 1.3%. The regression equation fitted the real situation better.
文摘A weakly coupled data assimilation system was established for a coupled physical–biological model for the northeastern South China Sea（NSCS）. The physical model used was the Regional Ocean Modeling System; the biological component was a seven-compartment nitrogen–phytoplankton–zooplankton–detritus ecosystem model; and the data assimilation method was Ensemble Optical Interpolation. To test the performance of the weakly coupled data assimilation system, two numerical experiments（i.e. control and assimilation runs） based on a process-oriented idealized case were conducted, and climatological SST was assimilated in the assimilation run. Only physical variables were adjusted in the weakly coupled data assimilation. The results showed that both the assimilated SST and other unassimilated physical variables had reasonable process responses. Due to the warmer SST observation, the water temperature（salinity） in the assimilation run increased（decreased） in coastal upwelling regions. Both the alongshore and bottom cross-shore currents were reduced, jointly demonstrating the weakening of the upwelling system. Meanwhile, ecosystem variables were also affected to some extent by the SST assimilation through the coupled model. For example, larger phytoplankton（chlorophyll） productivity was found in the upwelling region within the shallow layer due to the warmer waters in the assimilation run. Hence, the application of this data assimilation system could reasonably modify both physical and biological variables for the NSCS by SST assimilation.
文摘Response surface methodology (RSM) is used to optimize the medium of Tetraselmis sp.-1 which is cell fused microalgae capable of growing under mixotrophic condition. Empirical models are developed to describe the relationships between the operating variables (glucose, urea, sodium dehydrogenate phosphate, sodium chloride) and responses (cell density). Statistical analysis indicates that glucose and urea have significant effects on the microalgae cell density, but other two factors (sodium dehydrogenate phosphate, sodium chloride) have no obvious effect. The path of steepest ascent is used to approach the optimal region of medium composition. Optimal cell density (2.638 g dry weight/L) was reached when the operating conditions were glucose concentration (30.75 %), urea concentration (0.440 g/L), sodium dehydrogenate phosphate (15 mg/L) and sodium chloride (28 g/L).
文摘This paper presents a prey-predator model considering the predator interacting with non-refuges prey by class of functional responses. Here we also consider harvesting for only non-refuges prey. We discuss the equilibria of the model, and their stability for hiding prey either in constant form or proportional to the densities of prey population. We also investigate various possibilities of bionomic equilibrium and optimal harvesting policy. Finally we present numerical examples with pictorial presentation of the various effects of the prey predator system parameter.
