Inspired by the integrated guidance and control design for endo-atmospheric aircraft,the integrated position and attitude control of spacecraft has attracted increasing attention and gradually induced a wide variety o...Inspired by the integrated guidance and control design for endo-atmospheric aircraft,the integrated position and attitude control of spacecraft has attracted increasing attention and gradually induced a wide variety of study results in last over two decades,fully incorporating control requirements and actuator characteristics of space missions.This paper presents a novel and comprehensive survey to the coupled position and attitude motions of spacecraft from the perspective of dynamics and control.To this end,a systematic analysis is firstly conducted in details to show the position and attitude mutual couplings of spacecraft.Particularly,in terms of the time discrepancy between spacecraft position and attitude motions,space missions can be categorized into two types:space proximity operation and space orbital maneuver.Based on this classification,the studies on the coupled dynamic modeling and the integrated control design for position and attitude motions of spacecraft are sequentially summarized and analyzed.On the one hand,various coupled position and dynamic formulations of spacecraft based on various mathematical tools are reviewed and compared from five aspects,including mission applicability,modeling simplicity,physical clearance,information matching and expansibility.On the other hand,the development of the integrated position and attitude control of spacecraft is analyzed for two space missions,and especially,five distinctive development trends are captured for space operation missions.Finally,insightful prospects on future development of the integrated position and attitude control technology of spacecraft are proposed,pointing out current primary technical issues and possible feasible solutions.展开更多
[ Objective ] The paper was to explore the damage, occurrence pattern and integrated control methods of oriental fruit fly [ Bactrocera dorsalis ( Hen- del) ] in Nanning region of Guangxi Province. [ Method ] Using ...[ Objective ] The paper was to explore the damage, occurrence pattern and integrated control methods of oriental fruit fly [ Bactrocera dorsalis ( Hen- del) ] in Nanning region of Guangxi Province. [ Method ] Using fixed system survey method, with fruit fly attractants as the materials, the occurrence dynamic of oriental fruit fly adult in guava orchard was investigated. The control effects of the methods such as fruit fly attractants, fruit bagging, cleaning park to pick up fallen fruit and timely spraying pesticide against the pest were also studied. [ Result] Oriental fruit fly had two damage peak periods in Nanning region of Guangxi Prov- ince (May to June, August to September). Through the integrated control measures of trapping agent for male flies, timely spraying, fruit bagging and cleaning park to pick up fallen fruit, the population density in guava orchard dropped significantly. The fruit damage rates of guava in research base were only 6.67% -7.33% during the peak period of oriental fruit fly in June 2008, while they were 90.53% -98.00% in control area, obtaining good control effect against the pest. [ Con- dttalon ] The method used in the study preliminarily restored the yield losses of guava, which also provided basis for the preparation of overall strategy against orien- tal fruit fly in the region.展开更多
Tobacco black shank is one of the devastating diseases of tobacco. In recent years, this disease widely occurred in most tobacco-growing areas, which caused disastrous losses and has severely threatened the sustainabl...Tobacco black shank is one of the devastating diseases of tobacco. In recent years, this disease widely occurred in most tobacco-growing areas, which caused disastrous losses and has severely threatened the sustainable development of flue-cured tobacco. In order to lay a theoretical foundation for the better control of tobacco black shank, the occurrence characteristics and integrated control strategis of this disease were systematically discussed according to the aspects of agricultural control, chemical control, biological control, etc.展开更多
This paper explores and proposes a design solution of an integrated skip cycle mode (SCM) control circuit with a simple structure. The design is simulated and implemented with XD10H-1.0μm modular DIMOS 650 V proces...This paper explores and proposes a design solution of an integrated skip cycle mode (SCM) control circuit with a simple structure. The design is simulated and implemented with XD10H-1.0μm modular DIMOS 650 V process. In order to meet the requirement of a wide temperature range and high yields of products, the schematic extracted from the layout is simulated with five process corners at 27℃ and 90℃. Simulation results demonstrate that the proposed integrated circuit is immune to noise and achieves skipping cycle control when switching mode power supply (SMPS) works with low load or without load.展开更多
The integrated control system of vehicle ABS/ASR/ACC has been developed using the MC9S12DP256 single chip, which is the new Motorola 16-bit product in HSC12 family. The system including the main control module, the da...The integrated control system of vehicle ABS/ASR/ACC has been developed using the MC9S12DP256 single chip, which is the new Motorola 16-bit product in HSC12 family. The system including the main control module, the data collection module and the drive and fault diagnosis module is demonstrated and its data collection function is presented in detail. The system designed by the modularization can supervise the data, drive the valves and pump. The program can be debugged on line, which is steady and reliable validated by the large numbers of vehicle road tests.展开更多
The relevant factors for physiological chlorosis of Cinnamomum camphora L. in Pingdingshan were studied combining with references and production sur- vey. The resuhs showed that the disease was the integrated results ...The relevant factors for physiological chlorosis of Cinnamomum camphora L. in Pingdingshan were studied combining with references and production sur- vey. The resuhs showed that the disease was the integrated results of soil environment, planting situation, microenvironment construction and maintenance manage- ment. Therefore, the countermeasures of "prevention first, restore tree vigor; integrated control, enhance tree vigor" were proposed. Chlorosis of C. camphora had been basically controlled after four years, and the control effect was obvious.展开更多
This paper describes an intelligent integrated control of an acrobot, which is an underactuated mechanical system with second-order nonholonomic constraints. The control combines a model-free fuzzy control, a fuzzy sl...This paper describes an intelligent integrated control of an acrobot, which is an underactuated mechanical system with second-order nonholonomic constraints. The control combines a model-free fuzzy control, a fuzzy sliding-mode control and a model-based fuzzy control. The model-free fuzzy controller designed for the upswing ensures that the energy of the acrobot increases with each swing. Then the fuzzy sliding-mode controller is employed to control the movement that the acrobot enters the balance area from the swing-up area. The model-based fuzzy controller, which is based on a Takagi-Sugeno fuzzy model, is used to balance the acrobot. The stability of the fuzzy control system for balance control is guaranteed by a common symmetric positive matrix, which satisfies linear matrix inequalities.展开更多
Over the few last years, cucumber (Cucumis sativus L) root rot disease became common and inflicted marked losses to yield in Fayoum. Isolation trails from infected cucumber roots revealed that Thielaviopsis basicola...Over the few last years, cucumber (Cucumis sativus L) root rot disease became common and inflicted marked losses to yield in Fayoum. Isolation trails from infected cucumber roots revealed that Thielaviopsis basicola and Fusarium moniliforme were the main cucumber root rot pathogens. The isolation trials from the rhizosphere of healthy cucumber plants revealed that two fungal isolates and four bacterial isolates had antagonistic effects against cucumber root rot fungi. All the tested biocontrol agents reduced the radial growth of all the tested root rots fungi in dual cultures. However, all culture filtrates of the tested biocontrol agent significantly reduced radial growth of all the tested pathogenic fungi, except that T. harzianum. Under field conditions, soil treatment with any of T. harzianum and B. subtilis BI and BF, significantly reduced percentages of infected plants and significantly increased percentages of survived plants and fruit yield compared with the control. Application of the commercial product Harpin protein (Messenger)~ product, as a resistance inducer at 0.3, 0.5 and l g/L significantly reduced the percentage of infected plants under greenhouse and field conditions. Field experiments indicated that the average percentage of infected plants after 90 days significantly decreased. The percentage of the survived plants as well as fruit yield increased by using integrated disease management (IDM) package, including the most effective treatments: tolerant cultivar, Trichoderma harzianum granules formula as soil treatment, Purging cassia plant extract, Harpin protein, and a half dose of Vitavax/thiram comparing with the treatment recommended by the Ministry of Agricultural or applied treatments individually.展开更多
In view of the occurrence and aggravation of diseases and pests of horticultural crops,the management process should follow the basic policy of"prevention first,comprehensive control".Starting from the ecolo...In view of the occurrence and aggravation of diseases and pests of horticultural crops,the management process should follow the basic policy of"prevention first,comprehensive control".Starting from the ecological system,agricultural,biological,physical and chemical means should be comprehensively applied to control diseases and pests below the economic injury level.展开更多
Canker is a quarantine bacterial disease that seriously harms leaves,branches and fruits of citrus,leading to a decrease in the production and affecting the commodity and sales of citrus.Citrus canker has the characte...Canker is a quarantine bacterial disease that seriously harms leaves,branches and fruits of citrus,leading to a decrease in the production and affecting the commodity and sales of citrus.Citrus canker has the characteristics of fast spreading speed and difficult radical cure.Through the identification of symptoms and a summary of occurrence regularity,the integrated prevention and control technology for citrus canker is described in this article,in order to achieve effective prevention and control and reduce prevention and control cost.展开更多
Rice blast is the most devastating disease in rice,and it seriously threatens the safety of rice production.Improving the ability of integrated prevention and control of rice blast has always been an important part of...Rice blast is the most devastating disease in rice,and it seriously threatens the safety of rice production.Improving the ability of integrated prevention and control of rice blast has always been an important part of ensuring food production safety.In the past decade,scientists have made great progress in the prevention and control techniques of rice blast,which paves the way for the green controlling of rice diseases.In this article,the advances in the intelligentization of rice blast field monitoring techniques,the optimization of prediction and forecast modeling system,the research and development of low-toxic and high-efficiency chemical pesticides,biogenic pesticides and inducers and the regulation of multiple ecological factors including variety and cultivation are reviewed,and the new strategies for green controlling of rice blast based on these techniques are summarized.Further,the problems such as high pesticide prices and pesticide residue faced by rice blast prevention and control and the challenge of slow research and development of low-toxic and economical biogenic pesticides are discussed.Finally,the development direction of green controlling of rice blast based on molecular targets,small interfering RNA(siRNA)and CRISPR/Cas9 technologies is predicted,with a view to guaranteeing the safety of rice production.展开更多
In this paper,an integrated estimation guidance and control(IEGC)system is designed based on the command filtered backstepping approach for circular field-of-view(FOV)strapdown missiles.The threedimensional integrated...In this paper,an integrated estimation guidance and control(IEGC)system is designed based on the command filtered backstepping approach for circular field-of-view(FOV)strapdown missiles.The threedimensional integrated estimation guidance and control nonlinear model with limited actuator deflection angle is established considering the seeker's FOV constraint.The boundary time-varying integral barrier Lyapunov function(IBLF)is employed in backstepping design to constrain the body line-of-sight(BLOS)in IEGC system to fit a circular FOV.Then,the nonlinear adaptive controller is designed to estimate the changing aerodynamic parameters.The generalized extended state observer(GESO)is designed to estimate the acceleration of the maneuvering targets and the unmatched time-varying disturbances for improving tracking accuracy.Furthermore,the command filters are used to solve the"differential expansion"problem during the backstepping design.The Lyapunov theory is used to prove the stability of the overall closed-loop IEGC system.Finally,the simulation results validate the integrated system's effectiveness,achieving high accuracy strikes against maneuvering targets.展开更多
This paper investigates the damage symptoms and occurrence regularity related to coffee leaf rust,and proposes a comprehensive prevention and control strategy grounded in the principle of prioritizing prevention and i...This paper investigates the damage symptoms and occurrence regularity related to coffee leaf rust,and proposes a comprehensive prevention and control strategy grounded in the principle of prioritizing prevention and implementing integrated prevention and control.This strategy encompasses the cultivation of rust-resistant varieties,the implementation of agricultural practices,the application of chemical interventions,the utilization of hyperparasitic fungi,and the protection and utilization of natural enemies.The paper further outlines the necessary requirements for effective prevention and control,emphasizing the importance of enhancing responsibility implementation,fostering systematic prevention and control measures,enhancing guidance services,and increasing publicity and guidance.The aim is to offer technical guidance for the integrated prevention and control of coffee leaf rust in Yunnan Province.展开更多
Kiwifruit canker disease seriously affects the yield and quality of"Guichang"kiwifruit in Xiuwen County,Guizhou Province.In order to scientifically,safely,greenly and efficiently prevent and control the dise...Kiwifruit canker disease seriously affects the yield and quality of"Guichang"kiwifruit in Xiuwen County,Guizhou Province.In order to scientifically,safely,greenly and efficiently prevent and control the disease,theory was combined with prevention and control techniques to optimize existing prevention and control techniques,so as to improve the production yield and quality of kiwifruit.Specifically,biocontrol strains targeting local kiwifruit canker disease were screened,and reduced and mixed use of agrochemicals with improved efficiency was studied;and the effects and application techniques of disease resistance inducers and bioorganic fertilizers in inducing systemic disease resistance in kiwifruit trees were explored,and finally,an integrated green prevention and control scheme for kiwifruit canker disease that is suitable for kiwifruit production areas in Guizhou Province and has strong operability was proposed.This study provides technical support for green,efficient,standardized production technical services and sustainable and healthy development of kiwifruit industry.展开更多
Reversible watermarking schemes for relational database are usually classified into two groups: robust schemes and fragile schemes. The main limitation of existing reversible fragile methods is that they cannot differ...Reversible watermarking schemes for relational database are usually classified into two groups: robust schemes and fragile schemes. The main limitation of existing reversible fragile methods is that they cannot differentiate between legal and malicious modifications. In this paper, we introduce a novel lossless semi-fragile scheme based on prediction-error expansion for content protection of relational database. In the proposed method, all attributes in a database relation are first classified according to their sensitivity to legitimate updates. Then, the watermark is embedded by expanding the prediction error of the two least significant digits of securely selected attributes. At watermark extraction, the proposed method has the ability to fully restore the original data while detecting and localizing tampering. The applicability of our method is demonstrated theoretically and experimentally.展开更多
A winding system is a time-varying system that considers complex nonlinear characteristics,and how to control the stability of the winding tension during the winding process is the primary problem that has hindered de...A winding system is a time-varying system that considers complex nonlinear characteristics,and how to control the stability of the winding tension during the winding process is the primary problem that has hindered development in this field in recent years.Many nonlinear factors affect the tension in the winding process,such as friction,structured uncertainties,unstructured uncertainties,and external interference.These terms severely restrict the tension tracking performance.Existing tension control strategies are mainly based on the composite control of the tension and speed loops,and previous studies involve complex decoupling operations.Owing to the large number of calculations required for this method,it is inconvenient for practical engineering applications.To simplify the tension generation mechanism and the influence of the nonlinear characteristics of the winding system,a simpler nonlinear dynamic model of the winding tension was established.An adaptive method was applied to update the feedback gain of the continuous robust integral of the sign of the error(RISE).Furthermore,an extended state observer was used to estimate modeling errors and external disturbances.The model disturbance term can be compensated for in the designed RISE controller.The asymptotic stability of the system was proven according to the Lyapunov stability theory.Finally,a comparative analysis of the proposed nonlinear controller and several other controllers was performed.The results indicated that the control of the winding tension was significantly enhanced.展开更多
This paper presents a scheme of integrated guidance and autopilot design for homing missiles against ground fixed targets. An integrated guidance and control model in the pitch plane is formulated and further changed ...This paper presents a scheme of integrated guidance and autopilot design for homing missiles against ground fixed targets. An integrated guidance and control model in the pitch plane is formulated and further changed into a normal form by nonlinear coordinate transformation. By adopting the sliding mode control approach, an adaptive nonlinear control law of the system is designed so that the missile can hit the target accurately with a desired impact attitude angle. The stability analysis of the closed-loop system is also conducted. The numerical simulation has confirmed the usefulness of the proposed design scheme.展开更多
The real-time capability of integrated flight/propulsion optimal control (IFPOC) is studied. An appli- cation is proposed for IFPOC by combining the onboard hybrid aero-engine model with sequential quadratic pro- gr...The real-time capability of integrated flight/propulsion optimal control (IFPOC) is studied. An appli- cation is proposed for IFPOC by combining the onboard hybrid aero-engine model with sequential quadratic pro- gramming (SQP). Firstly, a steady-state hybrid aero-engine model is designed in the whole flight envelope with a dramatic enhancement of real-time capability. Secondly, the aero-engine performance seeking control including the maximum thrust mode and the minimum fuel-consumption mode is performed by SQP. Finally, digital simu- lations for cruise and accelerating flight are carried out. Results show that the proposed method improves real- time capability considerably with satisfactory effectiveness of optimization.展开更多
Di erential braking and active steering have already been integrated to overcome their shortcomings. However, existing research mainly focuses on two-axle vehicles and controllers are mostly designed to use one contro...Di erential braking and active steering have already been integrated to overcome their shortcomings. However, existing research mainly focuses on two-axle vehicles and controllers are mostly designed to use one control method to improve the other. Moreover, many experiments are needed to improve the robustness; therefore, these control methods are underutilized. This paper proposes an integrated control system specially designed for multi-axle vehicles, in which the desired lateral force and yaw moment of vehicles are determined by the sliding mode control algorithm. The output of the sliding mode control is distributed to the suitable wheels based on the abilities and potentials of the two control methods. Moreover, in this method, fewer experiments are needed, and the robustness and simultaneity are both guaranteed. To simplify the optimization system and to improve the computation speed, seven simple optimization subsystems are designed for the determination of control outputs on each wheel. The simulation results show that the proposed controller obviously enhances the stability of multi-axle trucks. The system improves 68% of the safe velocity, and its performance is much better than both di erential braking and active steering. This research proposes an integrated control system that can simultaneously invoke di erential braking and active steering of multi-axle vehicles to fully utilize the abilities and potentials of the two control methods.展开更多
基金supported by the National Science Foundation of China(61703437,52232014,61690210,61690212)。
文摘Inspired by the integrated guidance and control design for endo-atmospheric aircraft,the integrated position and attitude control of spacecraft has attracted increasing attention and gradually induced a wide variety of study results in last over two decades,fully incorporating control requirements and actuator characteristics of space missions.This paper presents a novel and comprehensive survey to the coupled position and attitude motions of spacecraft from the perspective of dynamics and control.To this end,a systematic analysis is firstly conducted in details to show the position and attitude mutual couplings of spacecraft.Particularly,in terms of the time discrepancy between spacecraft position and attitude motions,space missions can be categorized into two types:space proximity operation and space orbital maneuver.Based on this classification,the studies on the coupled dynamic modeling and the integrated control design for position and attitude motions of spacecraft are sequentially summarized and analyzed.On the one hand,various coupled position and dynamic formulations of spacecraft based on various mathematical tools are reviewed and compared from five aspects,including mission applicability,modeling simplicity,physical clearance,information matching and expansibility.On the other hand,the development of the integrated position and attitude control of spacecraft is analyzed for two space missions,and especially,five distinctive development trends are captured for space operation missions.Finally,insightful prospects on future development of the integrated position and attitude control technology of spacecraft are proposed,pointing out current primary technical issues and possible feasible solutions.
基金Supported by Educational Commission of Guangxi Province of China (GJR(2007)No.70)~~
文摘[ Objective ] The paper was to explore the damage, occurrence pattern and integrated control methods of oriental fruit fly [ Bactrocera dorsalis ( Hen- del) ] in Nanning region of Guangxi Province. [ Method ] Using fixed system survey method, with fruit fly attractants as the materials, the occurrence dynamic of oriental fruit fly adult in guava orchard was investigated. The control effects of the methods such as fruit fly attractants, fruit bagging, cleaning park to pick up fallen fruit and timely spraying pesticide against the pest were also studied. [ Result] Oriental fruit fly had two damage peak periods in Nanning region of Guangxi Prov- ince (May to June, August to September). Through the integrated control measures of trapping agent for male flies, timely spraying, fruit bagging and cleaning park to pick up fallen fruit, the population density in guava orchard dropped significantly. The fruit damage rates of guava in research base were only 6.67% -7.33% during the peak period of oriental fruit fly in June 2008, while they were 90.53% -98.00% in control area, obtaining good control effect against the pest. [ Con- dttalon ] The method used in the study preliminarily restored the yield losses of guava, which also provided basis for the preparation of overall strategy against orien- tal fruit fly in the region.
基金Supported by Project of Yunnan Tobacco Company of Science and Technology(2014YN20)
文摘Tobacco black shank is one of the devastating diseases of tobacco. In recent years, this disease widely occurred in most tobacco-growing areas, which caused disastrous losses and has severely threatened the sustainable development of flue-cured tobacco. In order to lay a theoretical foundation for the better control of tobacco black shank, the occurrence characteristics and integrated control strategis of this disease were systematically discussed according to the aspects of agricultural control, chemical control, biological control, etc.
文摘This paper explores and proposes a design solution of an integrated skip cycle mode (SCM) control circuit with a simple structure. The design is simulated and implemented with XD10H-1.0μm modular DIMOS 650 V process. In order to meet the requirement of a wide temperature range and high yields of products, the schematic extracted from the layout is simulated with five process corners at 27℃ and 90℃. Simulation results demonstrate that the proposed integrated circuit is immune to noise and achieves skipping cycle control when switching mode power supply (SMPS) works with low load or without load.
基金Ford-China Research and Development Fund Project(50122148)
文摘The integrated control system of vehicle ABS/ASR/ACC has been developed using the MC9S12DP256 single chip, which is the new Motorola 16-bit product in HSC12 family. The system including the main control module, the data collection module and the drive and fault diagnosis module is demonstrated and its data collection function is presented in detail. The system designed by the modularization can supervise the data, drive the valves and pump. The program can be debugged on line, which is steady and reliable validated by the large numbers of vehicle road tests.
文摘The relevant factors for physiological chlorosis of Cinnamomum camphora L. in Pingdingshan were studied combining with references and production sur- vey. The resuhs showed that the disease was the integrated results of soil environment, planting situation, microenvironment construction and maintenance manage- ment. Therefore, the countermeasures of "prevention first, restore tree vigor; integrated control, enhance tree vigor" were proposed. Chlorosis of C. camphora had been basically controlled after four years, and the control effect was obvious.
文摘This paper describes an intelligent integrated control of an acrobot, which is an underactuated mechanical system with second-order nonholonomic constraints. The control combines a model-free fuzzy control, a fuzzy sliding-mode control and a model-based fuzzy control. The model-free fuzzy controller designed for the upswing ensures that the energy of the acrobot increases with each swing. Then the fuzzy sliding-mode controller is employed to control the movement that the acrobot enters the balance area from the swing-up area. The model-based fuzzy controller, which is based on a Takagi-Sugeno fuzzy model, is used to balance the acrobot. The stability of the fuzzy control system for balance control is guaranteed by a common symmetric positive matrix, which satisfies linear matrix inequalities.
文摘Over the few last years, cucumber (Cucumis sativus L) root rot disease became common and inflicted marked losses to yield in Fayoum. Isolation trails from infected cucumber roots revealed that Thielaviopsis basicola and Fusarium moniliforme were the main cucumber root rot pathogens. The isolation trials from the rhizosphere of healthy cucumber plants revealed that two fungal isolates and four bacterial isolates had antagonistic effects against cucumber root rot fungi. All the tested biocontrol agents reduced the radial growth of all the tested root rots fungi in dual cultures. However, all culture filtrates of the tested biocontrol agent significantly reduced radial growth of all the tested pathogenic fungi, except that T. harzianum. Under field conditions, soil treatment with any of T. harzianum and B. subtilis BI and BF, significantly reduced percentages of infected plants and significantly increased percentages of survived plants and fruit yield compared with the control. Application of the commercial product Harpin protein (Messenger)~ product, as a resistance inducer at 0.3, 0.5 and l g/L significantly reduced the percentage of infected plants under greenhouse and field conditions. Field experiments indicated that the average percentage of infected plants after 90 days significantly decreased. The percentage of the survived plants as well as fruit yield increased by using integrated disease management (IDM) package, including the most effective treatments: tolerant cultivar, Trichoderma harzianum granules formula as soil treatment, Purging cassia plant extract, Harpin protein, and a half dose of Vitavax/thiram comparing with the treatment recommended by the Ministry of Agricultural or applied treatments individually.
文摘In view of the occurrence and aggravation of diseases and pests of horticultural crops,the management process should follow the basic policy of"prevention first,comprehensive control".Starting from the ecological system,agricultural,biological,physical and chemical means should be comprehensively applied to control diseases and pests below the economic injury level.
基金National Key R&D Program of China(2017YFD0202000)Project of Hubei Agricultural Science and Technology Innovation Center(2016-620-000-001-030).
文摘Canker is a quarantine bacterial disease that seriously harms leaves,branches and fruits of citrus,leading to a decrease in the production and affecting the commodity and sales of citrus.Citrus canker has the characteristics of fast spreading speed and difficult radical cure.Through the identification of symptoms and a summary of occurrence regularity,the integrated prevention and control technology for citrus canker is described in this article,in order to achieve effective prevention and control and reduce prevention and control cost.
基金Key R&D Project of Guangdong(2019B020217003)Science and Technology Plan Project of Guangzhou(202002030001)+2 种基金Fund for Modern Agro-Industry Technology Research System(CARS-01-32,2020KJ105)Natural Science Foundation of Guangdong(2020A1515011213)New Discipline Team Building Project of Guangdong Academy of Agricultural Sciences(202116TD).
文摘Rice blast is the most devastating disease in rice,and it seriously threatens the safety of rice production.Improving the ability of integrated prevention and control of rice blast has always been an important part of ensuring food production safety.In the past decade,scientists have made great progress in the prevention and control techniques of rice blast,which paves the way for the green controlling of rice diseases.In this article,the advances in the intelligentization of rice blast field monitoring techniques,the optimization of prediction and forecast modeling system,the research and development of low-toxic and high-efficiency chemical pesticides,biogenic pesticides and inducers and the regulation of multiple ecological factors including variety and cultivation are reviewed,and the new strategies for green controlling of rice blast based on these techniques are summarized.Further,the problems such as high pesticide prices and pesticide residue faced by rice blast prevention and control and the challenge of slow research and development of low-toxic and economical biogenic pesticides are discussed.Finally,the development direction of green controlling of rice blast based on molecular targets,small interfering RNA(siRNA)and CRISPR/Cas9 technologies is predicted,with a view to guaranteeing the safety of rice production.
文摘In this paper,an integrated estimation guidance and control(IEGC)system is designed based on the command filtered backstepping approach for circular field-of-view(FOV)strapdown missiles.The threedimensional integrated estimation guidance and control nonlinear model with limited actuator deflection angle is established considering the seeker's FOV constraint.The boundary time-varying integral barrier Lyapunov function(IBLF)is employed in backstepping design to constrain the body line-of-sight(BLOS)in IEGC system to fit a circular FOV.Then,the nonlinear adaptive controller is designed to estimate the changing aerodynamic parameters.The generalized extended state observer(GESO)is designed to estimate the acceleration of the maneuvering targets and the unmatched time-varying disturbances for improving tracking accuracy.Furthermore,the command filters are used to solve the"differential expansion"problem during the backstepping design.The Lyapunov theory is used to prove the stability of the overall closed-loop IEGC system.Finally,the simulation results validate the integrated system's effectiveness,achieving high accuracy strikes against maneuvering targets.
基金Supported by Innovation Guidance and Technology-based Enterprise Cultivation Program of Yunnan Science and Technology Project(202304BP090027).
文摘This paper investigates the damage symptoms and occurrence regularity related to coffee leaf rust,and proposes a comprehensive prevention and control strategy grounded in the principle of prioritizing prevention and implementing integrated prevention and control.This strategy encompasses the cultivation of rust-resistant varieties,the implementation of agricultural practices,the application of chemical interventions,the utilization of hyperparasitic fungi,and the protection and utilization of natural enemies.The paper further outlines the necessary requirements for effective prevention and control,emphasizing the importance of enhancing responsibility implementation,fostering systematic prevention and control measures,enhancing guidance services,and increasing publicity and guidance.The aim is to offer technical guidance for the integrated prevention and control of coffee leaf rust in Yunnan Province.
基金Supported by Science and Technology Support Program of Guizhou Province(QKHZC[2020]1Y135)General Higher Education Science and Technology Top-notch Talents Project of Guizhou Province(QJH KY Z[2021]037)+5 种基金Science and Technology Program of Guizhou Province(QKHJZ-ZK[2022]ZD 025)High-level Talent Scientific Research Startup Project of Guizhou Institute of Technology(XJGC20190632)Earth Thesis Project of Guizhou Institute of Technology(KJZX20-005)High-Level Talent Initial Funding of Guizhou Industry Polytechnic College(2023-RC-01)Enterprise Commissioned Project of Guizhou Industrial Polytechnic College(2023-HX-01)Enterprise Commissioned Project of Guizhou Industrial Polytechnic College(2023-HX-02).
文摘Kiwifruit canker disease seriously affects the yield and quality of"Guichang"kiwifruit in Xiuwen County,Guizhou Province.In order to scientifically,safely,greenly and efficiently prevent and control the disease,theory was combined with prevention and control techniques to optimize existing prevention and control techniques,so as to improve the production yield and quality of kiwifruit.Specifically,biocontrol strains targeting local kiwifruit canker disease were screened,and reduced and mixed use of agrochemicals with improved efficiency was studied;and the effects and application techniques of disease resistance inducers and bioorganic fertilizers in inducing systemic disease resistance in kiwifruit trees were explored,and finally,an integrated green prevention and control scheme for kiwifruit canker disease that is suitable for kiwifruit production areas in Guizhou Province and has strong operability was proposed.This study provides technical support for green,efficient,standardized production technical services and sustainable and healthy development of kiwifruit industry.
文摘Reversible watermarking schemes for relational database are usually classified into two groups: robust schemes and fragile schemes. The main limitation of existing reversible fragile methods is that they cannot differentiate between legal and malicious modifications. In this paper, we introduce a novel lossless semi-fragile scheme based on prediction-error expansion for content protection of relational database. In the proposed method, all attributes in a database relation are first classified according to their sensitivity to legitimate updates. Then, the watermark is embedded by expanding the prediction error of the two least significant digits of securely selected attributes. At watermark extraction, the proposed method has the ability to fully restore the original data while detecting and localizing tampering. The applicability of our method is demonstrated theoretically and experimentally.
基金Supported by National Key R&D Program of China (Grant No.2018YFB2000702)National Natural Science Foundation of China (Grant No.52075262)Fok Ying-Tong Education Foundation of China (Grant No.171044)。
文摘A winding system is a time-varying system that considers complex nonlinear characteristics,and how to control the stability of the winding tension during the winding process is the primary problem that has hindered development in this field in recent years.Many nonlinear factors affect the tension in the winding process,such as friction,structured uncertainties,unstructured uncertainties,and external interference.These terms severely restrict the tension tracking performance.Existing tension control strategies are mainly based on the composite control of the tension and speed loops,and previous studies involve complex decoupling operations.Owing to the large number of calculations required for this method,it is inconvenient for practical engineering applications.To simplify the tension generation mechanism and the influence of the nonlinear characteristics of the winding system,a simpler nonlinear dynamic model of the winding tension was established.An adaptive method was applied to update the feedback gain of the continuous robust integral of the sign of the error(RISE).Furthermore,an extended state observer was used to estimate modeling errors and external disturbances.The model disturbance term can be compensated for in the designed RISE controller.The asymptotic stability of the system was proven according to the Lyapunov stability theory.Finally,a comparative analysis of the proposed nonlinear controller and several other controllers was performed.The results indicated that the control of the winding tension was significantly enhanced.
基金Major Program of National Natural Science Founda-tion of China (60710002)Program for Changjiang Scholars and Innovative Research Team in University
文摘This paper presents a scheme of integrated guidance and autopilot design for homing missiles against ground fixed targets. An integrated guidance and control model in the pitch plane is formulated and further changed into a normal form by nonlinear coordinate transformation. By adopting the sliding mode control approach, an adaptive nonlinear control law of the system is designed so that the missile can hit the target accurately with a desired impact attitude angle. The stability analysis of the closed-loop system is also conducted. The numerical simulation has confirmed the usefulness of the proposed design scheme.
基金Supported by the Aeronautical Science Foundation of China(2010ZB52011)the Funding of Jiangsu Innovation Program for Graduate Education(CXLX11-0213)the Nanjing University of Aeronautics and Astronautics Research Funding(NS2010055)~~
文摘The real-time capability of integrated flight/propulsion optimal control (IFPOC) is studied. An appli- cation is proposed for IFPOC by combining the onboard hybrid aero-engine model with sequential quadratic pro- gramming (SQP). Firstly, a steady-state hybrid aero-engine model is designed in the whole flight envelope with a dramatic enhancement of real-time capability. Secondly, the aero-engine performance seeking control including the maximum thrust mode and the minimum fuel-consumption mode is performed by SQP. Finally, digital simu- lations for cruise and accelerating flight are carried out. Results show that the proposed method improves real- time capability considerably with satisfactory effectiveness of optimization.
基金National Natural Science Foundation of China(Grant No.51505178)China Postdoctoral Science Foundation(Grant No.2014M561289)
文摘Di erential braking and active steering have already been integrated to overcome their shortcomings. However, existing research mainly focuses on two-axle vehicles and controllers are mostly designed to use one control method to improve the other. Moreover, many experiments are needed to improve the robustness; therefore, these control methods are underutilized. This paper proposes an integrated control system specially designed for multi-axle vehicles, in which the desired lateral force and yaw moment of vehicles are determined by the sliding mode control algorithm. The output of the sliding mode control is distributed to the suitable wheels based on the abilities and potentials of the two control methods. Moreover, in this method, fewer experiments are needed, and the robustness and simultaneity are both guaranteed. To simplify the optimization system and to improve the computation speed, seven simple optimization subsystems are designed for the determination of control outputs on each wheel. The simulation results show that the proposed controller obviously enhances the stability of multi-axle trucks. The system improves 68% of the safe velocity, and its performance is much better than both di erential braking and active steering. This research proposes an integrated control system that can simultaneously invoke di erential braking and active steering of multi-axle vehicles to fully utilize the abilities and potentials of the two control methods.