The occurrence regularity of Phyllocnistis citreua in northern Guizhou was investigated,and the relationship between summer shoot controlling of citrus and occurrence of P. citreua was studied. The results showed that...The occurrence regularity of Phyllocnistis citreua in northern Guizhou was investigated,and the relationship between summer shoot controlling of citrus and occurrence of P. citreua was studied. The results showed that P. citreua occurred from May to September every year in northern Guizhou,and the occurrence reached the peak from early May to late June and from early July to late August. The occurrence in early and mid July was the most serious. The free-sprouting time had a close relationship with occurrence quantity and damage level of P. citreua. The earlier the free-sprouting time was,the greater the occurrence quantity and damage level of P. citreua was. The integrated control techniques focused on timely erasing summer shoots and controlling shoots were suggested to use in production,in order to control the occurrence of P. citreua.展开更多
According the to the model of single tank fire control system, this paper makes use of decomposition-coordination theory of large-scale systems to discuss the shooting problem of multiple tank the control systems, and...According the to the model of single tank fire control system, this paper makes use of decomposition-coordination theory of large-scale systems to discuss the shooting problem of multiple tank the control systems, and alalyzes specifically the three-tank the control systems and models.the process was imitated in computer, and the optimal shooting element of 3TS system was got. In addition, probability of hitting the target was calculated.展开更多
The optimal control of multibody spacecraft during the stretching process of solar arrays is investigated,and a hybrid optimization strategy based on Gauss pseudospectral method（GPM） and direct shooting method（DSM...The optimal control of multibody spacecraft during the stretching process of solar arrays is investigated,and a hybrid optimization strategy based on Gauss pseudospectral method（GPM） and direct shooting method（DSM） is presented. First, the elastic deformation of flexible solar arrays was described approximately by the assumed mode method, and a dynamic model was established by the second Lagrangian equation. Then, the nonholonomic motion planning problem is transformed into a nonlinear programming problem by using GPM. By giving fewer LG points, initial values of the state variables and control variables were obtained. A serial optimization framework was adopted to obtain the approximate optimal solution from a feasible solution. Finally, the control variables were discretized at LG points, and the precise optimal control inputs were obtained by DSM. The optimal trajectory of the system can be obtained through numerical integration. Through numerical simulation, the stretching process of solar arrays is stable with no detours, and the control inputs match the various constraints of actual conditions.The results indicate that the method is effective with good robustness.展开更多
Loss of Control (LOC) is the primary factor responsible for the majority of fatal air accidents during past decade. LOC is characterized by the pilot’s inability to control the aircraft and is typically associated wi...Loss of Control (LOC) is the primary factor responsible for the majority of fatal air accidents during past decade. LOC is characterized by the pilot’s inability to control the aircraft and is typically associated with unpredictable behavior, potentially leading to loss of the aircraft and life. In this work, the minimum time dynamic optimization problem to LOC is treated using Pontryagin’s Maximum Principle (PMP). The resulting two point boundary value problem is solved using stochastic shooting point methods via a differential evolution scheme (DE). The minimum time until LOC metric is computed for corresponding spatial control limits. Simulations are performed using a linearized longitudinal aircraft model to illustrate the concept.展开更多
根据生态环境学和现代森林病理学的原理与方法,通过多学科联合攻关,深入系统地研究了樟子松(Pinussylvestris var. mongolica)枯死的难题,搞清了樟子松枯死的起因与机理.提出以营林措施为主的防治技术对策,为经营樟子松人工林、增强林...根据生态环境学和现代森林病理学的原理与方法,通过多学科联合攻关,深入系统地研究了樟子松(Pinussylvestris var. mongolica)枯死的难题,搞清了樟子松枯死的起因与机理.提出以营林措施为主的防治技术对策,为经营樟子松人工林、增强林分的生态功能提供了依据.该项研究丰富了森林病理学内容,补充了松枯梢病的研究成果,为林间生产应用提供了科学依据和技术方法.展开更多
文摘The occurrence regularity of Phyllocnistis citreua in northern Guizhou was investigated,and the relationship between summer shoot controlling of citrus and occurrence of P. citreua was studied. The results showed that P. citreua occurred from May to September every year in northern Guizhou,and the occurrence reached the peak from early May to late June and from early July to late August. The occurrence in early and mid July was the most serious. The free-sprouting time had a close relationship with occurrence quantity and damage level of P. citreua. The earlier the free-sprouting time was,the greater the occurrence quantity and damage level of P. citreua was. The integrated control techniques focused on timely erasing summer shoots and controlling shoots were suggested to use in production,in order to control the occurrence of P. citreua.
文摘According the to the model of single tank fire control system, this paper makes use of decomposition-coordination theory of large-scale systems to discuss the shooting problem of multiple tank the control systems, and alalyzes specifically the three-tank the control systems and models.the process was imitated in computer, and the optimal shooting element of 3TS system was got. In addition, probability of hitting the target was calculated.
基金supported by the National Natural Science Foundation of China (11472058)
文摘The optimal control of multibody spacecraft during the stretching process of solar arrays is investigated,and a hybrid optimization strategy based on Gauss pseudospectral method（GPM） and direct shooting method（DSM） is presented. First, the elastic deformation of flexible solar arrays was described approximately by the assumed mode method, and a dynamic model was established by the second Lagrangian equation. Then, the nonholonomic motion planning problem is transformed into a nonlinear programming problem by using GPM. By giving fewer LG points, initial values of the state variables and control variables were obtained. A serial optimization framework was adopted to obtain the approximate optimal solution from a feasible solution. Finally, the control variables were discretized at LG points, and the precise optimal control inputs were obtained by DSM. The optimal trajectory of the system can be obtained through numerical integration. Through numerical simulation, the stretching process of solar arrays is stable with no detours, and the control inputs match the various constraints of actual conditions.The results indicate that the method is effective with good robustness.
文摘Loss of Control (LOC) is the primary factor responsible for the majority of fatal air accidents during past decade. LOC is characterized by the pilot’s inability to control the aircraft and is typically associated with unpredictable behavior, potentially leading to loss of the aircraft and life. In this work, the minimum time dynamic optimization problem to LOC is treated using Pontryagin’s Maximum Principle (PMP). The resulting two point boundary value problem is solved using stochastic shooting point methods via a differential evolution scheme (DE). The minimum time until LOC metric is computed for corresponding spatial control limits. Simulations are performed using a linearized longitudinal aircraft model to illustrate the concept.
文摘根据生态环境学和现代森林病理学的原理与方法,通过多学科联合攻关,深入系统地研究了樟子松(Pinussylvestris var. mongolica)枯死的难题,搞清了樟子松枯死的起因与机理.提出以营林措施为主的防治技术对策,为经营樟子松人工林、增强林分的生态功能提供了依据.该项研究丰富了森林病理学内容,补充了松枯梢病的研究成果,为林间生产应用提供了科学依据和技术方法.
